Colony Morphology

Almond anthracnose is a serious and emerging disease in several countries. All isolates causing almond anthracnose have been assigned to the Colletotrichum acutatum species complex, of which only C. fioriniae and C. godetiae have been associated with the disease to date. Here, we characterized Colletotrichum isolates from almond fruit affected by anthracnose in the Andalusia region. Two Colletotrichum isolates causing olive anthracnose were included for comparison. Morphological characteristics were useful for separating the isolates into groups based on colony morphology. Pathogenicity tests in almond, olive, and apple fruit showed differences in virulence and some degree of pathogenic specialization among isolates. Molecular characterization allowed clear identification of the Colletotrichum isolates tested. The olive isolates were identified as C. godetiae and C. nymphaeae, both previously identified in Andalusian olive orchards. Two phylogenetic species were identified among the almond isolates: C. godetiae, with gray colonies, which is well known in other countries, and C. acutatum, with pink-orange colonies. This species identification differs from those of pink-colony subpopulations described in other countries, which are C. fioriniae. Therefore, this study is also the first report of a new species of Colletotrichum causing almond anthracnose within the C. acutatum species complex.

Clusterbean is an important legume cultivated mostly on marginal and sub marginal lands of arid and semi-arid regions. Overall, India produces around 80% of global cluster bean production. The diseased samples were collected from Northern Madhya Pradesh for determining variability among collected twenty five isolates of Alternaria cucumerina var. cyamopsidis causal agent of Alternaria blight in Clusterbean based on conidial morphology and cultural variability on Potato dextrose agar medium. Out of twenty five isolates, five isolates viz: isolate A showed white with light olive black centre, isolate B was dark olive grey colour with white centre, isolate C and E were dark black and brown in colour respectively whereas the isolate D showed dark olive black colony with brown fluffy edge. On the basis of mycelial growth the isolate were found different in each other. The maximum conidial length was occurred in the isolate B (114.72 µm) and the conidial width was in the isolate B (7.0 µm...

Genus Trichoderma contains many species that are of great economic importance because of their ability to suppress pathogens and enhance their biocontrol capabilities against soil borne pathogens. In order to utilize the full potential of Trichoderma species in specific applications, precise identification and characterization are vital. The use of molecular markers has given a boost to the analysis of the accurate variation among various isolates of bio-agents. The present study was carried out to estimate the morphological diversity among commercial products of Trichoderma. Trichoderma based commercial products produced by different firms and made available for sales were collected from Akola and Nagpur markets. A total of eight isolates were isolated from talc powder carrier based samples on TSM. The Trichoderma isolates were differentiated by colony characters and morphological features. All isolates showed different growth patterns, colony colour, colony type, pigmentation and morphological characters like phialides, conidial size and shape.

The maintenance of the pluripotent state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1 -1.1 mm 2 ) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm 2 ) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A < 0.2 mm 2 ). The gaps between the cells, which are present in small and medium sized colonies with A ≤ 0.6 mm 2 , disappear in large colonies (A > 0.6 mm 2 ) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database.

Biofilm is commonly defined as accumulation of microbes, embedded in a self-secreted extra-cellular matrix, on solid surfaces or liquid interfaces. In this study, we analyze several aspects of Bacillus subtilis biofilm formation using tools from the field of image processing. Specifically, we characterize the growth kinetics and morphological features of B. subtilis colony type biofilm formation and compare these in colonies grown on two different types of solid media. Additionally, we propose a model for assessing B. subtilis biofilm complexity across different growth conditions. GFP-labeled B. subtilis cells were cultured on agar surfaces over a 4-day period during which microscopic images of developing colonies were taken at equal time intervals. The images were used to perform a computerized analysis of few aspects of biofilm development, based on features that characterize the different phenotypes of B. subtilis colonies. Specifically, the analysis focused on the segmented stru...

The maintenance of the pluripotent state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1 -1.1 mm 2 ) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm 2 ) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A < 0.2 mm 2 ). The gaps between the cells, which are present in small and medium sized colonies with A ≤ 0.6 mm 2 , disappear in large colonies (A > 0.6 mm 2 ) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database.

Eighty-five Colletotrichum isolates were obtained from soybean croplands in 34 municipalities of Mato Grosso state. Our objectives were characterize the isolates through mycelial growth, cultural and morphological analyses, as well as assessing pathogenicity. To evaluate cultural characteristics, the mycelial growth was daily measured, and the color of colonies was characterized after ten days incubation. The morphology, length, and width of 50 conidia per isolate were assessed. The pathogenicity of twenty-one isolates was evaluated on seed germination rate, incidence, and detection of extracellular enzymes. The cultural and morphology characteristics of Colletotrichum isolates were greatly variable. All isolates studied were able to reduce seed germination, produce sign and proteinase activity. These results suggest there are more than one Colletotrichum species associated with soybean anthracnose in Mato Grosso State.

Colony morphology may be an indicator of phenotypic variation, this being an important adaptive process adopted by bacteria to overcome environmental stressors. Furthermore, alterations in colony traits may reflect increased virulence and antimicrobial resistance. Despite the potential relevance of using colony morphological traits, the influence of experimental conditions on colony morphogenesis has been scarcely studied in detail. This study aims to clearly and systematically demonstrate the impact of some variables, such as colony growth time, plate colony density, culture medium, planktonic or biofilm mode of growth and strain genetic background, on bacterial colony morphology features using two Pseudomonas aeruginosa strains. Results, based on 5-replicate experiments, demonstrated that all variables influenced colony morphogenesis and 18 different morphotypes were identified, showing different sizes, forms, colours, textures and margins. Colony growth time and composition of the medium were the variables that caused the highest impact on colony differentiation both derived from planktonic and biofilm cultures. Colony morphology characterization before 45 h of incubation was considered inadequate and TSA, a non-selective medium, provided more colony diversity in contrast to P. aeruginosa selective media. In conclusion, data obtained emphasized the need to perform comparisons between colony morphologies in equivalent experimental conditions to avoid misinterpretation of microbial diagnostics and biomedical studies. Since colony morphotyping showed to be a reliable method to evaluate phenotypic switching and also to infer about bacterial diversity in biofilms, these unambiguous comparisons between morphotypes may offer a quite valuable input to clinical diagnosis, aiding the decision-making towards the selection of the most suitable antibiotic and supportive treatments.

Bacteria in nature are "plagued" by various unpredictable environmental stresses, being population diversity one of the strategies adopted to survive. Phenotypic switching is one of the evolution processes that causes commutation between phenotypic states. This phenomenon shows up as variation in colony morphology. Alterations in colony morphotype traits may reveal altered cellular basis phenotype which can confer ensured virulence, antimicrobial resistance and persistence. However, the specific correlation between those traits and the biological impact is unknown. Phenotypic switching also occurs during biofilm formation, in that, bacteria have to adapt to this mode of growth expressing different phenotype traits often distinct from those expressed during planktonic growth. Often, after severe stresses, it is observed the survival of a small non-growing population, the persisters cells. The persister-state is fully reversible under growth stimulating conditions and therefore does not depend on genetic alterations. Bacterial persistence has been pointed out as switching between growing and dormant cells. Nevertheless, not only the responsive switching to environmental changes is important for survival of bacteria. Inherent heterogeneity may also be of major importance in environmental adaptation and persistence. Control of stress-response gene expression determines whether bacteria can survive to changing conditions and compete for the resources it needs to proliferate. Reversible phenotypic switching offers considerable advantages over conventional irreversible mutations. This chapter discusses the impact of generating population-level diversity on important clinical issues as resistance, virulence and persistence. It highlights that even though the growing interest and relevance of this phenomenon and its impact on bacterial ecology, the evolutionary origins and adaptive significance remain poorly understood.

Colony morphology may be an indicator of phenotypic variation, this being an important adaptive process adopted by bacteria to overcome environmental stressors. Furthermore, alterations in colony traits may reflect increased virulence and antimicrobial resistance. Despite the potential relevance of using colony morphological traits, the influence of experimental conditions on colony morphogenesis has been scarcely studied in detail. This study aims to clearly and systematically demonstrate the impact of some variables, such as colony growth time, plate colony density, culture medium, planktonic or biofilm mode of growth and strain genetic background, on bacterial colony morphology features using two Pseudomonas aeruginosa strains. Results, based on 5-replicate experiments, demonstrated that all variables influenced colony morphogenesis and 18 different morphotypes were identified, showing different sizes, forms, colours, textures and margins. Colony growth time and composition of the medium were the variables that caused the highest impact on colony differentiation both derived from planktonic and biofilm cultures. Colony morphology characterization before 45 h of incubation was considered inadequate and TSA, a non-selective medium, provided more colony diversity in contrast to P. aeruginosa selective media. In conclusion, data obtained emphasized the need to perform comparisons between colony morphologies in equivalent experimental conditions to avoid misinterpretation of microbial diagnostics and biomedical studies. Since colony morphotyping showed to be a reliable method to evaluate phenotypic switching and also to infer about bacterial diversity in biofilms, these unambiguous comparisons between morphotypes may offer a quite valuable input to clinical diagnosis, aiding the decision-making towards the selection of the most suitable antibiotic and supportive treatments.

Bacteria in nature are "plagued" by various unpredictable environmental stresses, being population diversity one of the strategies adopted to survive. Phenotypic switching is one of the evolution processes that causes commutation between phenotypic states. This phenomenon shows up as variation in colony morphology. Alterations in colony morphotype traits may reveal altered cellular basis phenotype which can confer ensured virulence, antimicrobial resistance and persistence. However, the specific correlation between those traits and the biological impact is unknown. Phenotypic switching also occurs during biofilm formation, in that, bacteria have to adapt to this mode of growth expressing different phenotype traits often distinct from those expressed during planktonic growth. Often, after severe stresses, it is observed the survival of a small non-growing population, the persisters cells. The persister-state is fully reversible under growth stimulating conditions and therefore does not depend on genetic alterations. Bacterial persistence has been pointed out as switching between growing and dormant cells. Nevertheless, not only the responsive switching to environmental changes is important for survival of bacteria. Inherent heterogeneity may also be of major importance in environmental adaptation and persistence. Control of stress-response gene expression determines whether bacteria can survive to changing conditions and compete for the resources it needs to proliferate. Reversible phenotypic switching offers considerable advantages over conventional irreversible mutations. This chapter discusses the impact of generating population-level diversity on important clinical issues as resistance, virulence and persistence. It highlights that even though the growing interest and relevance of this phenomenon and its impact on bacterial ecology, the evolutionary origins and adaptive significance remain poorly understood.

In natural habitats, microorganisms are challenged all the time due to stress conditions imposed by the surrounding environment. To adapt to these environmental changes, bacteria alter their physiological and genetic traits. This adaptive behavior may be achieved by phenotype switching. This process consists in a reversible switch of phenotypes, as a mechanism ON/OFF, which occurs at high frequencies than spontaneous mutations. Colony morphology variation is the macroscopic feature of the phenotypic switching. Colony variation may have serious impact on bacterial virulence and antimicrobial resistance potentiating its ability to cause disease. Some colony variants are strongly associated to antibiotic resistance due to their presence in chronic infections despite antibiotic therapy. In cystic fibrosis, the switch of P. aeruginosa from non-mucoid to mucoid morphotype, which overproduce alginate, is a crucial stage to the establishment of this recalcitrant disease. Small colony variants (SCV) are other well-known resistant morphotype. These variants exhibited small size because its slow growth rate, pigmentation, haemolysis, reduced range of carbohydrate utilization and higher resistance to aminoglycosides antibiotics and cell-wall inhibitors.

Overuse of antibiotics is contributing to an emerging antimicrobial resistance crisis. To better understand how bacteria adapt tolerance and resist antibiotic treatment, Pseudomonas aeruginosa isolates obtained from infection sites sampled from companion animals were collected and evaluated for phenotypic differences. Selected pairs of clonal isolates were obtained from individual infection samples and were assessed for antibiotic susceptibility, cyclic di-GMP levels, biofilm production, motility and genetic-relatedness. A total of 18 samples from equine, feline and canine origin were characterized. A sample from canine otitis media produced a phenotypically heterogeneous pair of P. aeruginosa isolates, 42121A and 42121B, which during growth on culture medium respectively exhibited hyper dye-binding small colony morphology and wild-type phenotypes. Antibiotic susceptibility to gentamicin and ciprofloxacin also differed between this pair of clonal isolates. Sequence analysis of gyrA,...

Cystic fibrosis (CF) is the most common hereditary lung disease in the Caucasian population, characterized by viscous bronchial secretion, consecutive defective mucociliary clearance, and unavoidable colonization with microorganisms. Besides Pseudomonas aeruginosa, Staphylococcus aureus is the most common bacterial species colonizing the CF respiratory tract. Under antibiotic pressure S. aureus is able to switch to small colony variants (SCV). These small colony variants can invade epithelial cells, overcome antibiotic therapy inside the cells and can be the starting point for extracellular recolonization. The aim of the present study was the isolation and characterization of S. aureus small colony variants from Austrian cystic fibrosis patients. Samples collected from 147 patients were screened for the presence of S. aureus wild-type and small colony variants. Antibiotic susceptibility testing and determination of the small colony variants causing auxotrophism were performed. Wild-type isolates were assigned to corresponding small colony variants with spa typing. In total, 17 different small colony variant isolates and 12 corresponding wild-type isolates were obtained. 13 isolates were determined thymidine auxotroph, 2 isolates were auxotroph for hemin, and none of the tested isolates was auxotroph for both, respectively. The presence of SCVs is directly related to a poor clinical outcome, therefore a monitoring of SCV prevalence is recommended. This study revealed rather low SCV ratios in CF patients compared to other countries.

Seven isolates of Macrophomina phaseolina incitant of charcoal rot of maize, obtained from different agro-ecological zones of India, varied in their cultural characteristics and pathogenic behaviour. On the basis of colony colour, isolates were divided in to four groups i.e. grayish white, blackish gray, dark black in centre periphery cremish and cottony white colour. Hyderabad isolate produced highest number of sclerotia (180.3 sclerotia/9 mm disc and 52.0/ microscopic 10X field) of bigger size (95.7µm), whereas Coimbatore isolate produced minimum number of slcerotia (169 sclerotia) that too with smaller size (66.9 µm). On the basis of sclerotial morphology, two groups of isolates could be formed, the one with oblong shape having irregular edges and the other being round with regular edges. On the basis of disease expression the Hyderabad isolate was observed to be most virulent by giving maximum disease (8.8) while Coimbatore isolate was found to be least virulent as it exhibited a highest rating of 5.2 in the susceptible inbred CM 120 on a scale of 1-9. The noteworthy observation of the study was that sclerotial size and number had positive correlation with virulence.

Bacterial homeostasis depends on an array of physical and chemical stimulants. Current investigation assessed the impact of one of such factors, the speed of aeration, on cell viability and culturability of Escherichia coli, Pseudomonas spp. and Bacillus spp. Each of the bacterial strain was incubated at 37°C with a shaking speed of 0, 100 or 200 rotation per minute (rpm) separately up to 72 hours, with a simultaneous monitoring of morphological changes and cell culturability. All bacterial species were found to optimally grow at 100 rpm whereas at 0 rpm growths of E. coli and Pseudomonas spp. were bit slower compared to that of Bacillus spp. The capacity to form colony forming units (CFUs) of E. coli and Pseudomonas spp. on Luria Burtani (LB) agar plates were observed to be inhibited after 36 hours of growth at 200 rpm; i.e., approximately 3-log reduced CFUs than those formed by Bacillus spp. Besides, morphologically impaired cells were observed for the former two bacteria cultivated at 200 rpm. Taken together, it is assumed that the high speed shaking might evolve the oxidative stress endogenously which possibly rendered the cells lose their culturability.

The maintenance of the undifferentiated state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1-1.1 mm 2 ) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm 2 ) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A < 0.2 mm 2 ). The gaps between the cells, which are present in small and medium sized colonies with A ≤ 0.6 mm 2 , disappear in large colonies (A > 0.6 mm 2 ) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database. Human embryonic stem cells (hESCs) are pluripotent cells, derived from the blastocyst-stage embryos, which have the capacity to differentiate and give rise to all tissues of the body. More than 20 years ago, a method to derive stem cells from human embryos was discovered and allowed the use of these cells for further research in vitro 1 . They provide an opportunity to study early human development and the processes by which the undifferentiated state is lost and differentiation into different tissues occurs 2 . The specific signalling factors promoting stem cells to remain unspecialised in culture without differentiation have been highly optimised during the last two decades 3 . Also, protocols have been developed to differentiate hESCs towards all three germ layers for disease modelling, cell-based therapies and drug screening 4 . After the derivation of human induced pluripotent stem cells (hiPSCs) 5 , which made creating patient-matched embryonic stem cell lines feasible, hESCs and hiPSCs have become an emerging model for developmental studies and personalised medicine . Although the genetic and signalling pathways that control pluripotency in hESCs have been described in the last decade 9-14 , much less is known about the factors that control the arrangement of the cells into a pluripotent colony and how this affects pluripotency. Human ESCs grow as a multicellular colony. At the single cell level the transcription factors (TFs) associated with the maintenance of pluripotency fluctuate stochastically . These different expression states are maintained by different signalling, transcriptional, and epigenetic regulatory networks. However, pluripotency, considered as an emergent property of stem cell populations and their niches (rather than a property of single cells), is controlled by niche-mediated regulation in response to mechanical, chemical and physical stimuli . Thus, understanding how pluripotency is affected by cell segregation within the bulk of a colony is of practical importance in generating and selecting the optimum clones, and automating this for industrial-scale production.

The maintenance of the undifferentiated state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1-1.1 mm 2 ) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm 2 ) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A < 0.2 mm 2 ). The gaps between the cells, which are present in small and medium sized colonies with A ≤ 0.6 mm 2 , disappear in large colonies (A > 0.6 mm 2 ) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database. Human embryonic stem cells (hESCs) are pluripotent cells, derived from the blastocyst-stage embryos, which have the capacity to differentiate and give rise to all tissues of the body. More than 20 years ago, a method to derive stem cells from human embryos was discovered and allowed the use of these cells for further research in vitro 1 . They provide an opportunity to study early human development and the processes by which the undifferentiated state is lost and differentiation into different tissues occurs 2 . The specific signalling factors promoting stem cells to remain unspecialised in culture without differentiation have been highly optimised during the last two decades 3 . Also, protocols have been developed to differentiate hESCs towards all three germ layers for disease modelling, cell-based therapies and drug screening 4 . After the derivation of human induced pluripotent stem cells (hiPSCs) 5 , which made creating patient-matched embryonic stem cell lines feasible, hESCs and hiPSCs have become an emerging model for developmental studies and personalised medicine . Although the genetic and signalling pathways that control pluripotency in hESCs have been described in the last decade 9-14 , much less is known about the factors that control the arrangement of the cells into a pluripotent colony and how this affects pluripotency. Human ESCs grow as a multicellular colony. At the single cell level the transcription factors (TFs) associated with the maintenance of pluripotency fluctuate stochastically . These different expression states are maintained by different signalling, transcriptional, and epigenetic regulatory networks. However, pluripotency, considered as an emergent property of stem cell populations and their niches (rather than a property of single cells), is controlled by niche-mediated regulation in response to mechanical, chemical and physical stimuli . Thus, understanding how pluripotency is affected by cell segregation within the bulk of a colony is of practical importance in generating and selecting the optimum clones, and automating this for industrial-scale production.

The maintenance of the undifferentiated state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1-1.1 mm 2 ) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm 2 ) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A < 0.2 mm 2 ). The gaps between the cells, which are present in small and medium sized colonies with A ≤ 0.6 mm 2 , disappear in large colonies (A > 0.6 mm 2 ) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database. Human embryonic stem cells (hESCs) are pluripotent cells, derived from the blastocyst-stage embryos, which have the capacity to differentiate and give rise to all tissues of the body. More than 20 years ago, a method to derive stem cells from human embryos was discovered and allowed the use of these cells for further research in vitro 1 . They provide an opportunity to study early human development and the processes by which the undifferentiated state is lost and differentiation into different tissues occurs 2 . The specific signalling factors promoting stem cells to remain unspecialised in culture without differentiation have been highly optimised during the last two decades 3 . Also, protocols have been developed to differentiate hESCs towards all three germ layers for disease modelling, cell-based therapies and drug screening 4 . After the derivation of human induced pluripotent stem cells (hiPSCs) 5 , which made creating patient-matched embryonic stem cell lines feasible, hESCs and hiPSCs have become an emerging model for developmental studies and personalised medicine . Although the genetic and signalling pathways that control pluripotency in hESCs have been described in the last decade 9-14 , much less is known about the factors that control the arrangement of the cells into a pluripotent colony and how this affects pluripotency. Human ESCs grow as a multicellular colony. At the single cell level the transcription factors (TFs) associated with the maintenance of pluripotency fluctuate stochastically . These different expression states are maintained by different signalling, transcriptional, and epigenetic regulatory networks. However, pluripotency, considered as an emergent property of stem cell populations and their niches (rather than a property of single cells), is controlled by niche-mediated regulation in response to mechanical, chemical and physical stimuli . Thus, understanding how pluripotency is affected by cell segregation within the bulk of a colony is of practical importance in generating and selecting the optimum clones, and automating this for industrial-scale production.

Salmonella is one of the most common causes of foodborne outbreaks worldwide and can survive on various surfaces by virtue of its biofilm-producing capacity. Fimbriae play an essential role in attachment to the surface and the construction of cell aggregates; therefore, they are critical for the initialization of biofilm formation. In this study, Salmonella Typhimurium ATCC 14028 wild-type strain and its fimbrial mutant strains , , and biofilm-producing capacity on polystyrene and stainless-steel surfaces were compared at 24, 48, and 72 hours. In addition, the biofilm morphotypes and pellicle structures of strains were investigated. The findings revealed that biofilm formation was significantly reduced in the mutant strains compared to the wild strain on both surfaces. The biofilm-producing ability of the stjC mutant strain decreased by 75% on the polystyrene, and biofilm formation of the sthE mutant strain decreased by 72% on the stainless steel compared to wild-defined for wild-type, fimH, and sthE stjC mutant strain. Additionally, it was found that the mutant strains produced less cellulose than the wild-type. The pellicle formation observed in the mutant strains remarkably differed from that of the wild-type strain. This differentiation is more apparent in the stjC mutant strain, which produces less cellulose and has a tinier pellicle ring. These results highlight the importance of fimbriae in biofilm formation on different surfaces, suggesting that these structures can be notable targets for research aimed at eradicating Salmonella biofilms.

A new strain capable of forming distinctive patterns during colony development was identified by using a combination of phenotypic characterization, fatty acid analysis and analysis of the 16s rRNA gene sequence. The strain formed either a branched, tip-splitting colony morphology (referred to as the T morphotype) or a chiral pattern exhibiting thinner branches with distinctive curling patterns (referred to as the C morphotype). Isolates of the T morphotype exhibited sequence identities greater than 97 O/ o to Paenibacillus thiaminolyticus JCM 7540. Phylogenetic analysis placed the T morphotype within the Paenibacillus cluster on a phylogenetic tree. On the basis of unique colony morphology and distinctive phenotypic characteristics, it is proposed that the pattern-forming isolates should be placed within a new species of Paenibacillus, Paenibacillus dendritiformis sp. nov., the type strain of which is T168l(= 30A13.

When grown on agar surfaces, microbes can produce distinct multicellular spatial structures called colonies, which contain characteristic sizes, shapes, edges, textures, and degrees of opacity and color. For over one hundred years, researchers have used these morphology cues to classify bacteria and guide more targeted treatment of pathogens. Advances in genome sequencing technology have revolutionized our ability to classify bacterial isolates and while genomic methods are in the ascendancy, morphological characterization of bacterial species has made a resurgence due to increased computing capacities and widespread application of machine learning tools. In this paper, we revisit the topic of colony morphotype on the within-species scale and apply concepts from image processing, computer vision, and deep learning to a dataset of 69 environmental and clinical Pseudomonas aeruginosa strains. We find that colony morphology and complexity under common laboratory conditions is a robust,...

Almond anthracnose was reported for the first time in Australia in 1998 and has since been observed in all of the major almond-growing regions. The organism causing anthracnose was confirmed as Colletotrichum acutatum using taxon-specific polymerase chain reaction (PCR). Three main morphotypes of C. acutatum from almond in Australia were identified (namely, pink, orange, and cream colony color) and the optimum temperature for mycelial growth of representative isolates was 25°C. Australian isolates of C. acutatum were more similar morphologically to the pink subpopulation of C. acutatum from California than to the gray Californian subpopulation and the isolates of Colletotrichum from Israel. Inter-simple-sequence-repeat (ISSR) PCR analysis revealed that the majority of Australian isolates shared an identical banding pattern whereas Australian isolates of C. acutatum from almond were distinct from isolates of the pink and gray subpopulations of C. acutatum from almond in California an...

The research was conducted to study the morphological difference based on macroscopic and microscopic appearance of several Fusarium spp. Fusarium spp. isolates were propagated onto Potato Dextrose Agar (PDA) by using single-spore method. All isolates were observed macroscopically and microscopically to determine colony appearance, colony growth diameter and formation of macroconidia, microconidia and conidiophores. The results showed that colony appearance of all isolates was similar. Therefore they could not clearly be differentiated by one to another. On the other hand, microscopic observation showed that there was different conidiophore morphology of F. oxysporum and other Fusarium spp. Microscopic morphology among F. oxysporum isolates were difficult to differentiate. Microconidia were produced in false-head which was the characteristic feature of most F. oxysporum. In conclusion, microscopic morphology observation could only be able to differentiate Fusarium spp. isolates at s...

Purpose: To assess colony morphology of Staphylococcus aureus isolates for target shape (T1) and its utility in the identification of methicillin-resistant S. aureus (MRSA). Methods: Staphylococcus species isolated from blood cultures were studied for colony morphology characteristics. A polymerase chain reaction (PCR) test was performed on positive blood culture bottles for the detection of S. aureus and methicillin resistance. Colony morphology was read at 24 and 48 hours and defined as follows: target shaped (T1)-an elevated colony center encircled by a pale zone, which is surrounded by a single ring of peripheral enhancement giving a 'target' appearance; dome-shaped (T2) with an elevated center lacking the 'target' appearance. Results: At 48 hours, 73.7% of MRSA and 59.5% of coagulase-negative staphylococci (CoNS) showed T1 morphology. T1 morphology has a sensitivity of 73.68% and specificity of 93.55% amongst S. aureus for identification of methicillin resistance and a high positive predictive value (95.45%) at 48 hours. Conclusion: T1 morphology has a modest sensitivity with specificity and positive predictive value amongst S. aureus for identification of methicillin resistance at 48 hours. It can be potentially used for the identification of MRSA, especially in resource-limited settings and wherein a molecular test is not repeated if PCR testing has already identified methicillin-sensitive S. aureus (MSSA) on a recent specimen on the same patient.

Purpose: To assess colony morphology of Staphylococcus aureus isolates for target shape (T1) and its utility in the identification of methicillin-resistant S. aureus (MRSA). Methods: Staphylococcus species isolated from blood cultures were studied for colony morphology characteristics. A polymerase chain reaction (PCR) test was performed on positive blood culture bottles for the detection of S. aureus and methicillin resistance. Colony morphology was read at 24 and 48 hours and defined as follows: target shaped (T1)-an elevated colony center encircled by a pale zone, which is surrounded by a single ring of peripheral enhancement giving a 'target' appearance; dome-shaped (T2) with an elevated center lacking the 'target' appearance. Results: At 48 hours, 73.7% of MRSA and 59.5% of coagulase-negative staphylococci (CoNS) showed T1 morphology. T1 morphology has a sensitivity of 73.68% and specificity of 93.55% amongst S. aureus for identification of methicillin resistance and a high positive predictive value (95.45%) at 48 hours. Conclusion: T1 morphology has a modest sensitivity with specificity and positive predictive value amongst S. aureus for identification of methicillin resistance at 48 hours. It can be potentially used for the identification of MRSA, especially in resource-limited settings and wherein a molecular test is not repeated if PCR testing has already identified methicillin-sensitive S. aureus (MSSA) on a recent specimen on the same patient.

Research has shown that some pathogens, including Salmonella and other spore-formers, survive and remain viable in low-moisture foods (LMF). This review highlighted trends in publication and outlook of the research field, using articles published in Scopus between 2001 to 2020. Systematic article retrieval, data analysis, and trend visualization were conducted using Scopus analytical tools, Excel software, and VOSviewer, respectively. A total of 267 articles were published on the microbial safety of LMF, with a rapid rise in the number of publications per year. The U.S. has the highest research output (143 publications), followed by China (35 publications). Washington State University Pullman, USA, has the highest number of publications from a single institution, while Professor Juming Tang is the author with the highest number of publications. Evaluation of trends in LMF research highlighted an initial focus on the detection of possible microbial contaminants in the foods and exploring the relationship between water activity and microbial survival. Salmonella was identified as the leading cause of foodborne diseases associated with the consumption of LMF. Newer research is focusing on the molecular characterization of microbial contaminants of LMF and approaches to eliminate these pathogens and spoilage agents from LMF. In recent years, the trend has shifted towards the use of novel technologies for microbial and toxin inactivation to mitigate and minimize the risks due to the presence of these microbial agents and their metabolites in LMF.

Of thirty-three isolates of members of the form genera Acremonium and Cephalosporium screened for exopolysaccharide production, thirty proved positive in a medium with a high C: N ratio. Chemical studies suggest that the materials from strains giving the highest yields are homopolymers of glucose, l3-glucans. Production of these glucans is affected by both the quality and quantity of carbon and nitrogen sources in the medium, and in particular, yields in an A. persicinum isolate could be increased substantially by such culture manipulation to levels above 10 g 1-1. Polysaccharide synthesis in this fungus was inhibited by ammonium ions at low concentration.

Almond anthracnose was reported for the first time in Australia in 1998 and has since been observed in all of the major almond-growing regions. The organism causing anthracnose was confirmed as Colletotrichum acutatum using taxon-specific polymerase chain reaction (PCR). Three main morphotypes of C. acutatum from almond in Australia were identified (namely, pink, orange, and cream colony color) and the optimum temperature for mycelial growth of representative isolates was 25°C. Australian isolates of C. acutatum were more similar morphologically to the pink subpopulation of C. acutatum from California than to the gray Californian subpopulation and the isolates of Colletotrichum from Israel. Inter-simple-sequence-repeat (ISSR) PCR analysis revealed that the majority of Australian isolates shared an identical banding pattern whereas Australian isolates of C. acutatum from almond were distinct from isolates of the pink and gray subpopulations of C. acutatum from almond in California an...

Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta , and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in a heterogeneous environment.

Artikel Asli ISOLAT Streptococcus agalactiae ASAL SAP1 PENDERITA MASTITIS SUBKLINIS : I. Ekspresi fenotip isolat in vitro Streptococcus agalactiae isolates FROM SUBCLINICAL MASTITIS CATTLE : I. In vitto phenotypic expression of isolates Iwan H. ~t a m a ' , Ninuk S. ~e j e k i~ , I Made Sukada ' , dan I Wayan T. Wibawan ABSTRAK Sebanyak 36 isolat lapang Streptococcus agalactiae asal sapi penderita mastitis subklinis di daerah Bogor diamati ekspresi fenotipnya yang meliputi tipe hemolisis yang dihasilkan, kekeruhan pada supernatan media cair dan bentuk koloni pada media semi padat (Soft agar). Sebanyak sembilan, 15 dan 12 isolat memperlihatkan hemolisis tipe a, P, clan y. Ekspresi fenotip pada supernatan medium cair memperlihatkan 14 isolat dengan supernatan media keruh, 18 isolat dengan supernatan media sedikit kemh dan sisanya dengan supernatan media jernih. Sedangkan pada media semi padat memperlihatkan 15 isolat dengan bentuk koloni kebanyakan dlfus tebal, difus tipis dan kompak, 17 isolat dengan koloni kebanyakan difus tipis, difus tebal dan kompak, sisanya dengan koloni kompak tanpa adanya koloni difus. Terlihat adanya hubungan antara poia pertumbuhan pada media cair dan bentuk koloni pada media semi padat, keragaman koloni pada agar semi padat menunjukkan adanya variasi fase.

Aspergillus nidulans possesses three pmt genes encoding protein O-D-mannosyltransferases (Pmt). Previously, we reported that PmtA, a member of the PMT2 subfamily, is involved in the proper maintenance of fungal morphology and formation of conidia (T. Oka, T. Hamaguchi, Y. Sameshima, M. Goto, and K. Furukawa, Microbiology 150:1973-1982, 2004). In the present paper, we describe the characterization of the pmtA paralogues pmtB and pmtC. PmtB and PmtC were classified as members of the PMT1 and PMT4 subfamilies, respectively. A pmtB disruptant showed wild-type (wt) colony formation at 30°C but slightly repressed growth at 42°C. Conidiation of the pmtB disruptant was reduced to approximately 50% of that of the wt strain; in addition, hyperbranching of hyphae indicated that PmtB is involved in polarity maintenance. A pmtA and pmtB double disruptant was viable but very slow growing, with morphological characteristics that were cumulative with respect to either single disruptant. Of the three single pmt mutants, the pmtC disruptant showed the highest growth repression; the hyphae were swollen and frequently branched, and the ability to form conidia under normal growth conditions was lost. Recovery from the aberrant hyphal structures occurred in the presence of osmotic stabilizer, implying that PmtC is responsible for the maintenance of cell wall integrity. Osmotic stabilization at 42°C further enabled the pmtC disruptant to form conidiophores and conidia, but they were abnormal and much fewer than those of the wt strain. Apart from the different, abnormal phenotypes, the three pmt disruptants exhibited differences in their sensitivities to antifungal reagents, mannosylation activities, and glycoprotein profiles, indicating that PmtA, PmtB, and PmtC perform unique functions during cell growth.

Aspergillus nidulans possesses three pmt genes encoding protein O - d -mannosyltransferases (Pmt). Previously, we reported that PmtA, a member of the PMT2 subfamily, is involved in the proper maintenance of fungal morphology and formation of conidia (T. Oka, T. Hamaguchi, Y. Sameshima, M. Goto, and K. Furukawa, Microbiology 150: 1973-1982, 2004). In the present paper, we describe the characterization of the pmtA paralogues pmtB and pmtC . PmtB and PmtC were classified as members of the PMT1 and PMT4 subfamilies, respectively. A pmtB disruptant showed wild-type (wt) colony formation at 30°C but slightly repressed growth at 42°C. Conidiation of the pmtB disruptant was reduced to approximately 50% of that of the wt strain; in addition, hyperbranching of hyphae indicated that PmtB is involved in polarity maintenance. A pmtA and pmtB double disruptant was viable but very slow growing, with morphological characteristics that were cumulative with respect to either single disruptant. Of the...

Background Phenotypic switching generates fungal colonies with altered morphology and allows pathogens to adapt to changing environments. Objective This study investigated the structure of switched colonies in Candida tropicalis. Methods The switched variant strains (crepe and rough) were analyzed for colony morphology at the ultrastructural level-SEM. The distribution and composition of the extracellular matrix (ECM) were evaluated. The percentage of hyphae was determined by direct counting using light microscopy. The gene expression for these responses was measured by RT-qPCR. Results The macromorphology of the switched variants exhibited high complexity, showing depressions, irregular edges, and a greater amount of ECM than the original strain. In addition, rough variant colonies showed higher amounts of total carbohydrates and proteins in ECM (p&lt;0.05). We also observed a positive correlation between BCR1 (Biofilm cell regulator) gene expression and carbohydrate content in the...

Pleurotus ostreatus fungus forms an edible mushroom that possesses important nutritional and medicinal properties. Selenium (Se) is essential to human diets and it is in low concentration in the soil, and consequently in food. P. ostreatus was grown in coffee husks enriched with various concentrations of sodium selenite. The biological efficiency of P. ostreatus was affected by the addition of high concentrations of Se. The highest level of Se absorption was obtained by adding 51 mg kg 1 of sodium selenite. The mushrooms from first flush contained more Se than the further flushes. These results demonstrate the great potential of coffee husks in the production of Se-enriched mushrooms and show the ability of this fungus to absorb and biomagnify Se.

Serratia liquefaciens is a gram-negative bacterium characterized by its motility due to peritrichous flagella and distinctive colony morphology, presenting as cream, pink, or red with smooth margins and an iridescent sheen. Optimal growth occurs between 10-36°C with pH tolerance from 5-9 and salt tolerance up to 4% NaCl. Isolation and identification are achieved using selective and differential media such as EMB and MAC agars, where it shows non-lactose-fermenting properties. Clinically, S. liquefaciens is pathogenic, causing transfusion-related infections and hospital-acquired infections due to its virulence factors like DNases and proteases. It also affects food quality by causing rot diseases in fruits. However, its virulence factors have shown potential for agricultural and pharmaceutical applications, including antibacterial and chitinolytic properties and remediation of heavy metal contamination in soils. Recent research highlights its ability to reduce arsenic accumulation in rice, demonstrating significant potential for agricultural biotechnology advancements.

A long-standing interest in marine science is in the degree to which environmental conditions of flow and irradiance, combined with optical, thermal and morphological characteristics of individual coral colonies, affects their sensitivity of thermal microenvironments and susceptibility to stress-induced bleaching within and/or among colonies. The physiological processes in Scleractinian corals tend to scale allometrically as a result of physical and geometric constraints on body size and shape. There is a direct relationship between scaling to thermal stress, thus, the relationship between allometric scaling and rates of heating and cooling in coral microenvironments is a subject of great interest. The primary aim of this study was to develop an approximation that predicts coral thermal microenvironments as a function of colony morphology (shape and size), light or irradiance, and flow velocity or regime. To do so, we provided intuitive interpretation of their energy budgets for both massive and branching colonies, and then quantified the heat-size exponent (b*) and allometric constant (m) using logarithmic linear regression. The data demonstrated a positive relationship between thermal rates and changes in irradiance, A/V ratio, and flow, with an interaction where turbulent regime had less influence on overall stress which may serve to ameliorate the effects of temperature rise compared to the laminar regime. These findings indicated that smaller corals have disproportionately higher stress, however they can reach thermal equilibrium quicker. Moreover, excellent agreements between the predicted and simulated microscale temperature values with no significant bias were observed for both the massive and branching colonies, indicating that the numerical approximation should be within the accuracy with which they could be measured. This study may assist in estimating the coral microscale temperature under known conditions of water flow and irradiance, in particular when examining the intra-and inter-colony variability found during periods of bleaching conditions.

Bacteria in nature are widely exposed to differential fluid shears which are often a trigger for phenotypic switches. The latter mediates transcriptional and translation remodeling of cellular metabolism impacting among others virulence, antimicrobial resistance and stress resistance. In this study, we evaluated the role of fluid shear on phenotypic switch in an acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus M0904 strain under both in vitro and in vivo conditions. The results showed that V. parahaemolyticus M0904 grown at lower shaking speed (110 rpm constant agitation, M0904/110), causing low fluid shear, develop cellular aggregates or floccules. These cells increased levan production (as verified by concanavalin binding) and developed differentially stained colonies on Congo Red agar plates and resistance to antibiotics. In addition, the phenotypic switch causes a major shift in the protein secretome. At 120 rpm (M0904/120), PirA/B toxins are mainly produced, while at 110 rpm PirA/B toxin production is stopped and an alkaline phosphatase PhoX becomes the dominant protein in the protein secretome. These observations are matched with a very strong reduction in virulence of M0904/110 towards two crustacean larvae, namely Artemia and Macrobrachium. Taken together, our study provides substantial evidence for the existence of two phenotypic forms in AHPND Vibrio parahaemolyticus strain displaying differential phenotypes. Moreover, as aerators and pumping devices are frequently used in shrimp aquaculture facilities, they can inflict fluid shear to the standing microbial agents. Hence, our study could provide a basis to understand the behaviour of AHPND-causing Vibrio parahaemolyticus in aquaculture settings and open the possibility to monitor and control AHPND by steering phenotypes.

The microbial colony growth is driven by the activity of the cells located on the edges of the colony. However, this process is not visible unless specific staining or cross-sectioning of the colony is done. Speckle imaging technology is a non-invasive method that allows visualization of the zones of increased microbial activity within the colony. In this study, the laser speckle imaging technique was used to record the growth of the microbial colonies. This method was tested on three different microorganisms: Vibrio natriegens, Escherichia coli, and Staphylococcus aureus. The results showed that the speckle analysis system is not only able to record the growth of the microbial colony but also to visualize the microbial growth activity in different parts of the colony. The developed speckle imaging technique visualizes the zone of “the highest microbial activity” migrating from the center to the periphery of the colony. The results confirm the accuracy of the previous models of colo...

In this study, the microbial contamination of smartphones from Italian University students was analyzed. A total of 100 smartphones classified as low, medium, and high emission were examined. Bacteria were isolated on elective and selective media and identified by biochemical tests. The mean values of cfu/cm 2 were 0.79 ± 0.01; in particular, a mean of 1.21 ± 0.12, 0.77 ± 0.1 and 0.40 ± 0.10 cfu/cm 2 was present on smartphones at low, medium, and high emission, respectively. The vast majority of identified microorganisms came from human skin, mainly Staphylococci, together with Gram-negative and positive bacilli and yeasts. Moreover, the main isolated species and their mixture were exposed for 3 h to turned on and off smartphones to evaluate the effect of the electromagnetic wave emission on the bacterial cultivability, viability, morphology, and genotypic profile in respect to the unexposed broth cultures. A reduction rate of bacterial growth of 79 and 46% was observed in Staphylococcus aureus and Staphylococcus epidermidis broth cultures, respectively, in the presence of turned on smartphone. No differences in viability were observed in all detected conditions. Small colony variants and some differences in DNA fingerprinting were detected on bacteria when the smartphones were turned on in respect to the other conditions. The colonization of smartphones was limited to human skin microorganisms that can acquire phenotype and genotypic modifications when exposed to microwave emissions.

Burkholderia pseudomallei (Bp), the agent of melioidosis, causes disease ranging from acute and rapidly fatal to protracted and chronic. Bp is highly infectious by aerosol, can cause severe disease with nonspecific symptoms, and is naturally resistant to multiple antibiotics. However, no vaccine exists. Unlike many Bp strains, which exhibit random variability in traits such as colony morphology, Bp strain MSHR5848 exhibited two distinct and relatively stable colony morphologies on sheep blood agar plates: a smooth, glossy, pale yellow colony and a flat, rough, white colony. Passage of the two variants, designated "Smooth" and "Rough", under standard laboratory conditions produced cultures composed of > 99.9% of the single corresponding type; however, both could switch to the other type at different frequencies when incubated in certain nutritionally stringent or stressful growth conditions. These MSHR5848 derivatives were extensively characterized to identify variant-associated differences. Microscopic and colony morphology differences on six differential media were observed and only the Rough variant metabolized sugars in selective agar. Antimicrobial susceptibilities and lipopolysaccharide (LPS) features were characterized and phenotype microarray profiles revealed distinct metabolic and susceptibility disparities between the variants. Results using the phenotype microarray system narrowed the 1,920 substrates to a subset which differentiated the two variants. Smooth grew more rapidly in vitro than Rough, yet the latter exhibited a nearly 10-fold lower lethal dose for mice than Smooth. Finally, the Smooth variant was phagocytosed and replicated to a greater extent and was more cytotoxic than Rough in macrophages. In contrast, multiple locus sequence type (MLST) analysis, ribotyping, and whole genome sequence analysis demonstrated the variants' genetic

The ability to emit and receive signals over long distances is one of the characteristic attributes of multicellular organisms. Such communication can be mediated in different manners (by chemical compounds, light waves, acoustic waves etc.) and usually is reflected in the behaviour of the communicating organisms. Recently, we reported that individual yeast colonies, organised multicellular structures, can also communicate at long distance by means of volatile ammonia, which is produced by colonies in pulses separated by acidification of the medium. Here, we demonstrate that the colony that first reached the stage of intense ammonia production induces ammonia production response in surrounding colonies regardless of their age, causing the synchronisation of their NH3 pulses and, consequently, the mutual affection of their growth. Also an artificial source of ammonia (but neither NH4+ nor NaOH gradients) can immediately induce the ammonia production even in the colony starting its ac...

Eighty-five Colletotrichum isolates were obtained from soybean croplands in 34 municipalities of Mato Grosso state. Our objectives were characterize the isolates through mycelial growth, cultural and morphological analyses, as well as assessing pathogenicity. To evaluate cultural characteristics, the mycelial growth was daily measured, and the color of colonies was characterized after ten days incubation. The morphology, length, and width of 50 conidia per isolate were assessed. The pathogenicity of twenty-one isolates was evaluated on seed germination rate, incidence, and detection of extracellular enzymes. The cultural and morphology characteristics of Colletotrichum isolates were greatly variable. All isolates studied were able to reduce seed germination, produce sign and proteinase activity. These results suggest there are more than one Colletotrichum species associated with soybean anthracnose in Mato Grosso State.

An investigation was carried out on the occurrence of thermotolerant and thermophilic fungi in 11 soil samples collected from cultivated and natural regions in Kermanshah province (Mahidasht, Harsin, Kerend, Eslamabad-e Gharb, Qasr-e Shirin, Sarpol-e Zahab, Javanrood, Gilan-e Gharb), municipal waste compost and mushroom compost, 2017-19. Fungal isolates were recovered using the soil dilution plate method on potato dextrose agar at 45 and 50 °C. Totally, 24 isolates were obtained that were primarily identified using morphological characters and referring to valid taxonomic keys. DNA extraction was carried out using a Genomic DNA Purification kit. The ITS region (ITS1-5.8S-ITS2) of the ribosomal DNA was amplified using ITS1 and ITS4 primers. Fragments about 500-700 bp were amplified after sequencing deposited in GenBank. Based on morphological characters and sequence data of the ITS rDNA, these fungi were identified as: Aspergillus fumigatus, A. nidulans, A. niger, A. terrus, Melanocarpus albomyces*, Malbranchea cinnamomea*, Thermomyces dupontii*, Th. lanuginosus*, and Thielavia arenaria*. Asterisks indicate species that are new records for the mycobiota of Iran. The abundance of thermophilic fungi in municipal waste compost was higher than soil, and Aspergillus species were the most abundant fungi identified in this study.