Chlamydospore Formation Research Articles

Isolation and Identification Of Candida Albicans In Smokers With Epithelial Dysplasia And Squamous Cell Carcinoma: A Histopathological Correlation

Background:Greater adaptability of Candida to the host niche makes it the most common opportunistic pathogen. Its role as a commensal or pathogen in development of premalignancies and its progression to malignancies is of considerable debate. Present study was undertaken to determine the role of Candida albicans(CA)in progressionof oral cancer by isolation and identification by mycological methods in smokers without oral lesions and histopathologically diagnosed cases of epithelial dysplasia (ED) and oral squamous cell carcinoma (OSCC). Methodology:The study comprised of 120 cases that included study group of 40 smokers with oral lesions, 40 smokers without oral lesions and 40 non-smokers as control group. Clinical examination was followed by oral rinse sample collection and biopsy for histopathological confirmation. Sedimented oral rinse was inoculated on Sabouraud’s dextrose agar (SDA). Isolated Candida colony after identification with Gram stain was subjected to germ tube and chlamydospore formation test for confirmation of CA. The data was statistically analysed using chi square test. Results:Colonisation of CA was 52.5% in the study group and 5% in the control group, was found to be statistically significant (p<0.001).Association of CA in smokers with varying histopathologic grades of oral lesions showed no evidence of a correlation. However, positive correlation was found in OSCC (n=19, 95%) and showed statistical significance (p<0.001). Conclusion:The present study showed an increase in colonization of CA in malignant lesions suggesting that CA in conjunction with tobacco usage may play a role in oral carcinogenesis.

A Brg1-Rme1 circuit in Candida albicans hyphal gene regulation.

Major Candida albicans virulence traits include its ability to make hyphae, to produce a biofilm, and to damage host cells. These traits depend upon expression of hypha-associated genes. A gene expression comparison among clinical isolates suggested that transcription factor Rme1, established by previous studies to be a positive regulator of chlamydospore formation, may also be a negative regulator of hypha-associated genes. Engineered RME1 overexpression supported this hypothesis, but no relevant rme1Δ/Δ mutant phenotype was detected. We reasoned that Rme1 may function within a specific regulatory pathway. This idea was supported by our finding that an rme1Δ/Δ mutation relieves the need for biofilm regulator Brg1 in biofilm formation. The impact of the rme1Δ/Δ mutation is most prominent under static or "biofilm-like" growth conditions. RNA sequencing (RNA-seq) of cells grown under biofilm-like conditions indicates that Brg1 activates hypha-associated genes indirectly via repression of RME1: hypha-associated gene expression levels are substantially reduced in a brg1Δ/Δ mutant and partially restored in a brg1Δ/Δ rme1Δ/Δ double mutant. An rme1Δ/Δ mutation does not simply bypass Brg1, because iron homeostasis genes depend upon Brg1 regardless of Rme1. Rme1 thus connects Brg1 to the targets relevant to hypha and biofilm formation under biofilm growth conditions.IMPORTANCECandida albicans is a major fungal pathogen of humans, and its ability to grow as a surface-associated biofilm on implanted devices is a common cause of infection. Here, we describe a new regulator of biofilm formation, RME1, whose activity is most prominent under biofilm-like growth conditions.

Morphological and Molecular Characterization of the Pathogen Associated with Infected Leaf and Fruits of Tomato

This investigation describes the morpho-molecular characterization of the pathogen associated with infected leaf and fruits of tomato (Solanum lycopersicum L.). The fungal pathogen was identified based on their cultural morphology, microscopic features and analysis of Internal Transcribed Spacer (ITS) region sequences of nuclear ribosomal DNA (nrDNA). Cultural morphology including colour of the young and mature colony, growth pattern, concentric rings etc. and microscopic features including shape and size of microconidia, macroconidia, phialide, shape of apical and basal cells of macroconidia, septation in conidia, inter-septal distance and formation of chlamydospores corroborated the identity with the pathogenic fungi Fusarium oxysporum. The phylogenetic analysis based ITS regions sequences of nrDNA of the fungal isolate showed 100% identity with Fusarium oxysporum. Thus the ITS of nrDNA sequences validated the morphological data. Pathogenicity test also reconfirmed the identity of the test isolate of Fusarium oxysporum. The Chittagong Univ. J. B. Sci.,Vol. 10(1 &2):31-40, 2020.

Enhanced Labor Management: Implementing WHO Recommendations in Oyo State Nursing Practice

Introduction: An increase in the incidence of Urinary tract infections due to Candida species has been observed. The higher rate of Candiduria due to Non albicans Candida is now being reported than due to Candida albicans.The emergence of drug resistance in Candida species has complicated the patient management. Aim: to observe the prevalence of Candida species in UTIs and their antifungal susceptibility pattern in a tertiary care hospital. Materials and Methods: An observational study was conducted fora period of three months in NIMS, Jaipur. Symptomatic patients belonging to all age groups were included in the study. Catheterized or clean catch midstream urine were centrifuged and the sediment was plated on Sabouraud’s Dextrose Agar slants with and without Chloramphenicol. A wet mount preparation was also made and looked for the presence of pus cells, yeast cells, pseudohyphae, etc. Yeast were identified by using germ tube, Chromogenic agar, chlamydospore formation and carbohydrate assimilation tests. Antifungalsusceptibility testing was performed on Muller Hinton Methylene Blue Agar. Result: The Candida species were isolated in only 24 (4.8%) samples. Only 8 cases yielded Candida albicans(33.33%). The highest cases were found to be of Candida tropicalis (n=14) while remaining two cases has growth of Candida krusai (n=1) and Candida glabrata (n=1). Keywords: WHO guidelines, labor management, and patient care & outcomes.

Again and Again-Survival of Candida albicans in Urine Containing Antifungals.

Relapse of Candida albicans urinary tract infection (UTI) is frequent despite appropriate treatment, as commonly used antifungals such fluconazole and flucytosine are only fungistatics. To improve treatment of Candida UTI and decrease relapses, understanding the long-term metabolic activity and survival of C. albicans in urine containing antifungals at minimal inhibitory concentration (MIC) is needed. we monitored the survival, metabolic activity and consumption of glucose and proteins by C. albicans using conventional methods and isothermal microcalorimetry (IMC). We also investigated the influence of dead Candida cells on the growth of their living counterparts. For 33 days, weak activity was observed in samples containing antifungals in which C. albicans growth rate was reduced by 48%, 60% and 88%, and the lag increased to 172 h, 168 h and 6 h for amphotericin, flucytosine and fluconazole, respectively. The metabolic activity peaks corresponded to the plate counts but were delayed compared to the exhaustion of resources. The presence of dead cells promoted growth in artificial urine, increasing growth rate and reducing lag in similar proportions. Even with antifungal treatment, C. albicans relapses are possible. The low metabolic activity of surviving cells leading to regrowth and chlamydospore formation possibly supported by autophagy are likely important factors in relapses.

Prediction Model for Pregnancy Success in IVF Program in the Poor Prognosis Group

Introduction: An increase in the incidence of Urinary tract infections due to Candida species has been observed. The higher rate of Candiduria due to Non albicans Candida is now being reported than due to Candida albicans.The emergence of drug resistance in Candida species has complicated the patient management. Aim: to observe the prevalence of Candida species in UTIs and their antifungal susceptibility pattern in a tertiary care hospital. Materials and Methods: An observational study was conducted fora period of three months in NIMS, Jaipur. Symptomatic patients belonging to all age groups were included in the study. Catheterized or clean catch midstream urine were centrifuged and the sediment was plated on Sabouraud’s Dextrose Agar slants with and without Chloramphenicol. A wet mount preparation was also made and looked for the presence of pus cells, yeast cells, pseudohyphae, etc. Yeast were identified by using germ tube, Chromogenic agar, chlamydospore formation and carbohydrate assimilation tests. Antifungalsusceptibility testing was performed on Muller Hinton Methylene Blue Agar. Result: The Candida species were isolated in only 24 (4.8%) samples. Only 8 cases yielded Candida albicans(33.33%). The highest cases were found to be of Candida tropicalis (n=14) while remaining two cases has growth of Candida krusai (n=1) and Candida glabrata (n=1). Keywords: Infertility, prediction model, In Vitro Fertilization, Logistic Regression, Endometrial Thickness, Poor Prognosis, Clinical Pregnancy

الكشف عن بعض عوامل الضراوة بين المبيضات المعزولة من المرضى وانتشار جين candidalysin ECE1

المبيضات البيضاء هي مسبب شائع لعدوى الجهاز التنفسي وداء المبيضات الفموي لدى الناس ، ومسببات أمراض الخميرة الانتهازية والأسباب الرئيسية للمرض والوفيات لدى الأشخاص الذين يعانون من نقص المناعة وتسبب التهابات سطحية على الأسطح المخاطية التي تصيب ملايين الأشخاص في جميع أنحاء العالم. كان الهدف الرئيسي من هذه الدراسة هو التحقق من انتشار بعض عوامل الضراوة التي لها القدرة على تكوين الأغشية الحيوية (Biofilm)، والبروتينيز (Proteinase)، وإنتاج الهيمولايسين( Hymolysine) بين عزلات C. albicans التي تشمل انتشار جين Candidalysin (ECE1). تم جمع العينات خلال الفترة من ايار 2022 الى اب 2022 من 280 عينة (مسحة) لمرضى عراقيين من مختلف الاعمار والاجناس غير مكررين كانوا يعانون من داء المبيضات الفموي وامراض الجهاز التنفسي في مستشفيات بغداد (مستشفى مدينه الطب و مستشفى اليرموك التعليمي ومستشفى مدينه الامامين الطبية التعليمية). تم زراعة العينات التي تم جمعها على وسط اكار السابرويد دكستروز (SDA) مضاف اليه كلورامفينيكول كمضاد للبكتيريا بتركيز 10 ميكجم / مل ، وتم حضن الاطباق الملقحة على وسط SDA عند 37 درجة مئوية لمدة تتراوح بين 24-48 ساعة.أظهرت نتائج الاستنبات أن 102 عينة كانت موجبه، منها58 (56.86%) من تجويف الفم و 44 (43.14%) من الجهاز التنفسي، بينما 178 منها كانت سالبة , تم الكشف عن عزلات المبيضات باستخدام الطرق التقليدية والتي تشمل (النمو على وسط HiCrome Candida ، إنتاج الأنبوب الجرثومي Germ tube ، تكوين الابواغ الكلاميديه Clamydospore وتم تأكيد نتئج التعريف باستخدام نضام VITEK-2 بينت النتائج ان من بين 102 عزلة C. albicans هي الاكثر شيوعا بين الانواع بنسبة 68.63 % ثم تلتها C. tropicalis بنسبة %10.78 ثم C. kruzei %5.88 وC. kefyr %5.88 C. parapsilosis % 4.9 بينما كانت C. glabrata % 3.9 وتمثل النسبة الاقل بين الانواع . تم فحص حساسية عزلات المبيضات للأدوية المضادة للفطريات بطريقة انتشار القرص ، والتي أجريت على النحو الموصى به بواسطة(CLSI) M44-A -وثيقة . أظهرت العزلات درجة عالية من الحساسية للأمفوتريسين-ب 93.14% وكلوتريمازول 90.20% ونسياتين 85.92% ،تم التحقق من انتشار جينCandidalysin (ECE1) بين 70 عزلة من C. albicans باستخدام تقنية تفاعل البلمرة المتسلسل PCR ، وأظهرت النتائج أن 41 58.57% تحتوي على جين Ece1 في تجويف الفم والجهاز التنفسي. و 34 عزلة 48.57% من C. albicans كانت منتجة قوية للغشاء الحيوي, بينما 30 عزلة 42.86% عزلة انتجت بروتيناز و 20 عزلة 28.57% عزلة لديها القدرة على تحلل الدم.

Occurrence and antimicrobial resistance patterns of bacterial and fungal pathogens from patients with urinary tract infections in Ojo, Lagos Nigeria

Urinary tract infections (UTIs) is a common bacterial and fungal infection affecting millions of people globally. The aim of this study was to investigate the distribution and antimicrobial susceptibility patterns of bacteria and fungi from patients with UTI. Urine samples were collected aseptically from patients with symptoms of UTI in sterile universal containers from five hospitals in a period of three months. A total of 200 urine samples from 75 males and 125 females were analyzed and subjected to culture, biochemical identification and antimicrobial susceptibility testing using the Kirby-Bauer technique. Fungal isolates were identified based on cultural characteristics, lactophenol cotton blue stain, chlamydospore formation, and colony colour on CHROM agar Candida medium. Most samples were positive for one microorganism each and a few had two isolates, thus giving a frequency of 210 microbial isolates. The most commonly isolated bacteria were Escherichia coli, 71(34%), followed by Staphylococcus aureus, 63(30%), Enterobacter spp., 32(15.2%), Klebsiella spp., 17(8.1%), Proteus mirabillis, 15(7.1%) and Candida albicans 12(5.7%), being the only fungus isolated. Antimicrobial susceptibility testing showed that Escherichia coli showed 57.7% susceptibility to streptomycin. Klebsiella spp. were 70.5% susceptible to septrin, but with susceptibility as low as 47.1% to chloramphenicol. Enterobacter spp. showed 71.9% susceptibility to septrin, 68.8% to gentamycin, 59.4% to streptomycin and chloramphenicol, 53.1%. Proteus spp showed 53.5%, and 66.7% to pefloxacin, septrin and streptomycin respectively. Staphylococcus aureus showed susceptibility of 56(88.9%), 55(87.3%), and 47 (74.6%) to gentamicin, ciprofloxacin. and pefloxacin respectively. Candida albicans was highly susceptible to nystatin, fluconazole and miconazole by 7(58.3%) but was highly resistant to ketoconazole, 41.7%. The findings of this study provide valuable information on the distribution of bacterial and fungal agents that are common etiology of UTIs, and likely antimicrobial drugs for the treatment of UTIs.

Conformation Techniques for False Smut Pathogen (U. virens) on Rice through Cultural and Molecular Tools in Telangana

The study was conducted during period of January to April, 2022 at the Department of Plant Pathology and Institute of Biotechnology, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad, Telangana state, India. The main objective of this study was to investigate cultural and morphological characteristics of U. virens isolates on potato sucrose medium (PSA) and their molecular confirmation collected from rice growing regions of Telangana during the kharif (rainy season), 2021. The isolates showed varying colony diameters and growth rates, with Uv3 reaching a maximum diameter of 77 mm and a growth rate of 2.85 mm, while Uv11 exhibited a minimum diameter of 40 mm with a growth rate of 1.48 mm. Notably, twenty two isolates showed diverse characteristics, including colony color, elevation, zonation, sectoring, and chlamydospore formation. Cluster analysis revealed the formation of five major groups, each group containing isolates with distinct features and PCR amplification with universal and species-specific primers yielded products of 700 bp and 380 bp, respectively. Phylogenetic tree analysis, indicated, Uv3 and Uv15 belonged to clade X and clade VII, respectively, both comprising Indian isolates. In contrast, Uv4 was grouped under clade II, which included both Chinese and Indian isolates. The proposed technique coupled with information of U. virens will immensely contribute to further studies on this fungus and false smut disease in India.

Enhanced control efficacy of Bacillus subtilis NM4 via integration of chlorothalonil on potato early blight caused by Alternaria solani

Early blight caused by Alternaria solani is a common foliar disease of potato around the world, and serious infections result in reduced yields and marketability due to infected tubers. The major aim of this study is to figure out the synergistic effect between microorganism and fungicides and to evaluate the effectiveness of Bacillus subtilis NM4 in the control of early blight in potato. Based on its colonial morphology and a 16S rRNA analysis, a bacterial antagonist isolated from kimchi was identified as B. subtilis NM4 and it has strong antifungal and anti-oomycete activity against several phytopathogenic fungi and oomycetes. The culture filtrate of strain NM4 with the fungicide effectively suppressed the mycelial growth of A. solani, with the highest growth inhibition rate of 83.48%. Although exposure to culture filtrate prompted hyphal alterations in A. solani, including bulging, combining it with the fungicide caused more severe hyphal damage with continuous bulging. Surfactins and fengycins, two lipopeptide groups, were isolated and identified as the main compounds in two fractions using LC-ESI-MS. Although the surfactin-containing fraction failed to inhibit growth, the fengycin-containing fraction, alone and in combination with chlorothalonil, restricted mycelial development, producing severe hyphal deformations with formation of chlamydospores. A pot experiment combining strain NM4, applied as a broth culture, with fungicide, at half the recommended concentration, resulted in a significant reduction in potato early blight severity. Our results indicate the feasibility of an integrated approach for the management of early blight in potato that can reduce fungicide application rates, promoting a healthy ecosystem in agriculture.

Variations in Morpho-Cultural Characteristics and Pathogenicity of Fusarium moniliforme of Bakanae Disease of Rice and Evaluation of In Vitro Growth Suppression Potential of Some Bioagents

Bakanae is one of the important diseases of rice in Bangladesh that causes substantial yield loss every year. We collected thirty isolates of Fusarium spp. from bakanae-infected rice plants from different agroecological zones of Bangladesh and investigated the variations in cultural and morphological characteristics and pathogenicity. Diversity was found in cultural characteristics, viz., colony features, phialide, chlamydospore formation, shape, and size of macro- and microconidia. Three variants of Fusarium species such as F. moniliforme, F. fujikuroi, and F. proliferatum were identified on PDA media based on their cultural and morphological characteristics. Isolate FM10 (F. moniliforme) exhibited the highest disease aggressiveness in developing elongated plants (26.50 cm), the highest number of chlorotic leaves (5.75), and a lower germination percentage. We evaluated different bioagents against the virulent isolate of F. moniliforme to develop a rice bakanae disease management approach. Four bioagents, viz., Trichoderma spp., Bacillus subtilis, Pseudomonas fluorescens, and Achromobacter spp., were evaluated for growth suppression of F. moniliforme. Among the bioagents, Achromobacter spp. and B. subtilis (BS21) showed 73.54% and 71.61% growth suppression, respectively. The investigation revealed that the application of Achromobacter spp. and B. subtilis (BS21) would be a potential candidate for effective and eco-friendly management of the bakanae disease of rice.

Prevalence and drug susceptibility of clinical Candida species in nasopharyngeal cancer patients in Vietnam

In the nature, Candida species are normal inhabitants and can be observed in a wide variety of vertebrates. In humans, especially for cancer patients who fall prey to opportunistic pathogens, this group of susceptible multi-drug resistant and biofilm-forming yeasts, are among the commonest ones. In this study, Candida species in 76 oral lesion samples from Vietnamese nasopharyngeal-cancer patients were isolated, morphologically identified using CHROMagar™, germ tube formation, and chlamydospore formation tests, and molecularly confirmed by PCR-RFLP. The drug susceptibility of these isolates was then tested, and the gene ERG11 was DNA sequenced to investigate the mechanism of resistance.The results showed that Candida albicans remained the most prevalent species (63.16% of the cases), followed by Candida glabrata, Candida tropicalis, and Candida krusei. The rates of resistance of non-albicans Candida for tested drugs were 85.71%, 53.57%, and 57.14% to fluconazole, clotrimazole, and miconazole, respectively. Although the drug-resistance rate of Candida albicans was lower than that of non-albicans Candida, it was higher than expected, suggesting an emerging drug-resistance phenomenon. Furthermore, ERG11 DNA sequencing revealed different mutations (especially K128T), implying the presence of multiple resistance mechanisms. Altogether, the results indicate an alarming drug-resistance situation in Candida species in Vietnamese cancer patients and emphasize the importance of species identification and their drug susceptibility prior to treatment.

Isolation, identification, and antifungal resistance of Candida species from various samples

This study in Aden, Yemen, collected 67 samples from patients attending hospitals and laboratories. Samples were taken from different body areas, covering various age groups and genders. Fungal infections, particularly Candida species, are a significant cause of death worldwide. The emergence of azole-resistant Candida has raised concerns and highlighted the need for better antifungal agents.In the study, 68.66% of the collected samples contained pathogenic Candida fungi. Some samples also showed bacterial growth or both bacteria and fungi. Suspected Candida growth on corn meal agar exhibited chlamydospore formation and germ tubes on human serum. Carbohydrate fermentation tests were positive for Glucose, Maltose, Galactose, and Xylose, while Sucrose and Lactose were negative. All Candida isolates (100%) were accurately identified to the species level using CHROM agar Candida. Candida's pathogenicity was linked to various virulence factors, including hydrolytic enzyme secretion. Nystatin was the most effective antifungal agent (100% sensitivity), while Fluconazole (73.92%) and Amphotericin B (52.17%) showed varying levels of sensitivity. However, Voriconazole, ketoconazole, and Miconazole displayed high resistance rates (89.13%, 84.78%, and 80.44%, respectively) against the isolated Candida.This study concluded that Candida spp., particularly Candida albicans, were frequently found in the samples from patients, with vaginal swaps being a common site of infection. The identification of Candida isolates to the species level using CHROM agar Candida was accurate. Nystatin, Fluconazole, and Amphotericin B were the most effective antifungal agents against Candida spp.

Biochemical typing and evaluation of pathogenicity in vulvovaginal isolates of Candida albicans complex

Candida albicans, C. dubliniensis, and C. africana form the Candida albicans complex. To identify the phenotypic and pathogenic characteristics of isolates of the C. albicans complex preserved in a collection. Three hundred presumptive strains of the C. albicans complex were evaluated using CHROMagarTM Candida. Germ tube production was determined by three methods, chlamydospores formation was assessed and colonies were characterized in artisanal agars (Rosmarinus officinalis and Nicotiana tabacum). MALDI-TOF was used as the gold standard identification test. To detect pathogenicity factors, we evaluated the hemolytic activity of each isolate and cocultured with Staphylococcus aureus, coagulase enzyme production, and biofilm formation. Out of the 300 isolates, 43.7% produced germ tube in the heart-brain infusion broth and 47% of the isolates produced chlamydospores. In the artisan media, 6% of the isolates produced brown colonies on rosemary agar and 5% did so on tobacco agar. None of the strains hemolyzed the blood agar alone or cocultured with S. aureus. However, 50% of the isolates hemolyzed the potato dextrose agar supplemented with blood. All strains were coagulase producers, and biofilm production was variable. For germ tube production, the human serum method showed the same positivity as the milk broth method. All isolates were identified as C. albicans by MALDI-TOF. The use of proteomics, molecular tests or a combination of methods is required for species identification.

Detection of pulmonary candidiasis in immunocopromasied Iraq patients by conventional polymerase chain reaction technique

Candida species was possible to cause pulmonary candidiasis, this infection commonly occurred in" immunocompromised patients. This study aimed to isolate and diagnose of pulmonary candidiasis by using molecular method (Conventional PCR). This study was included a total of hundred and fifty (n=150) samples of bronchoalveolar lavage were collected from 100 immunocompromised patients with underlying diverse diseases and control group included 50 bronchoalveolar lavage from immunocompetent individuals were composed from in-and out patients who attended of Al-Imammian Al-Kadhmain Medical City, Baghdad teaching Hospital, Baghdad, during the period from May 2014 to March 2015. Samples were cultured on CHROMagar and after that detected by using API 20 Candida stripe for initial identification of Candida isolates. Germ tube test, chlamydospore formation were also performed to reinforce identification them DNA isolates was extracted for conventional polymerase chain reaction (PCR) method. Results showed that all apparently healthy individuals samples were negative by conventional PCR. Concerning immunocompromised patients with underlying different diseases, 60 out of 100 samples revealed negative results by each of conventional and molecular methods Only 38 (38%) immunocompromised patients had positive results by molecular and conventional methods and two samples (2%) positive result by molecular methods also "show that CHROMagar was a good tool for initial identification of Candida isolates. This study concludes that candidasis may be as opportunistic infection among immunocompromised patients and PCR method confirmed more suitable diagnosed other than culture on CHROMagar medium and other phenotypic technique".

AfLaeA, a Global Regulator of Mycelial Growth, Chlamydospore Production, Pathogenicity, Secondary Metabolism, and Energy Metabolism in the Nematode-Trapping Fungus Arthrobotrys flagrans.

Arthrobotrys flagrans (Duddingtonia flagrans) is a typical nematode-trapping fungus which has been used for nematode biocontrol. The global regulator LaeA is widely distributed in filamentous fungi and plays a crucial role in secondary metabolism and development in addition to pathogenicity in fungal pathogens. In this study, the chromosome-level genome of A. flagrans CBS 565.50 was sequenced and homologous sequences of LaeA were identified in A. flagrans. A. flagrans LaeA (AfLaeA) knockout resulted in slower hyphal growth and a smoother hyphal surface. Importantly, deletion of AfLaeA resulted in the absence of chlamydospores and attenuated glycogen and lipid accumulation in hyphae. Similarly, disruption of the AfLaeA gene led to fewer traps and electron-dense bodies, lower protease activity, and a delay in capturing nematodes. The AfLaeA gene had a large effect on the secondary metabolism of A. flagrans, and both the deletion and overexpression of AfLaeA could yield new compounds, whereas some compounds were lost due to the absence of the AfLaeA. Protein-protein interactions between AfLaeA and another eight proteins were detected. Furthermore, transcriptome data analysis showed that 17.77% and 35.51% of the genes were influenced by the AfLaeA gene on days 3 and 7, respectively. AfLaeA gene deletion resulted in the higher expression level of the artA gene cluster, and multiple differentially expressed genes involved in glycogen and lipid synthesis and metabolism showed opposite expression patterns in wild-type and ΔAfLaeA strains. In summary, our results provide novel insights into the functions of AfLaeA in mycelial growth, chlamydospore production, pathogenicity, secondary metabolism, and energy metabolism in A. flagrans. IMPORTANCE The regulation of biological functions, such as the secondary metabolism, development, and pathogenicity of LaeA, has been reported in multiple fungi. But to date, no study on LaeA in nematode-trapping fungi has been reported. Moreover, it has not been investigated whether or not LaeA is involved in energy metabolism and chlamydospore formation has not been investigated. Especially in the formation mechanism of chlamydospores, several transcription factors and signaling pathways are involved in the production of chlamydospores, but the mechanism of chlamydospore formation from an epigenetic perspective has not been revealed. Concurrently, an understanding of protein-protein interactions will provide a broader perspective on the regulatory mechanism of AfLaeA in A. flagrans. This finding is critical for understanding the regulatory role of AfLaeA in the biocontrol fungus A. flagrans and establishes a foundation for developing high-efficiency nematode biocontrol agents.

The secretory Candida effector Sce1 licenses fungal virulence by masking the immunogenic β-1,3-glucan and promoting apoptosis of the host cells.

Candida albicans deploys a variety of mechanisms such as morphological switch and elicitor release to promote virulence. However, the intricate interactions between the fungus and the host remain poorly understood, and a comprehensive inventory of fungal virulence factors has yet to be established. In this study, we identified a C. albicans secretory effector protein Sce1, whose induction and secretion are associated with vagina-simulative conditions and chlamydospore formation. Sequence alignment showed that Sce1 belongs to a Pir family in C. albicans, which is conserved across several fungi and primarily characterized as a β-glucan binding protein in the Saccharomycescerevisiae. Mechanically, Sce1 is primarily localized to the cell wall in a cleaved form as an alkali-labile β-1,3-glucan binding protein and plays a role in masking β-glucan in acidic environments and chlamydospores, a feature that might underline C. albicans' ability to evade host immunity. Further, a cleaved short form of Sce1 protein could be released into extracellular compartments and presented in bone marrow-derived macrophages infected with chlamydospores. This cleaved short form of Sce1 also demonstrated a unique ability to trigger the caspases-8/9-dependent apoptosis in various host cells. Correspondingly, genetic deletion of SCE1 led to dampened vaginal colonization of C. albicans and diminished fungal virulence during systemic infection. The discovery of Sce1 as a versatile virulence effector that executes at various compartments sheds light on the fungus-host interactions and C. albicans pathogenesis.

A transcription factor and a phosphatase regulate temperature-dependent morphogenesis in the fungal plant pathogen Zymoseptoria tritici

Naturally fluctuating temperatures provide a constant environmental stress that requires adaptation. Some fungal pathogens respond to heat stress by producing new morphotypes that maximize their overall fitness. The fungal wheat pathogen Zymoseptoria tritici responds to heat stress by switching from its yeast-like blastospore form to hyphae or chlamydospores. The regulatory mechanisms underlying this switch are unknown. Here, we demonstrate that a differential heat stress response is ubiquitous in Z. tritici populations around the world. We used QTL mapping to identify a single locus associated with the temperature-dependent morphogenesis and we found two genes, the transcription factor ZtMsr1 and the protein phosphatase ZtYvh1, regulating this mechanism. We find that ZtMsr1 regulates repression of hyphal growth and induces chlamydospore formation whereas ZtYvh1 is required for hyphal growth. We next showed that chlamydospore formation is a response to the intracellular osmotic stress generated by the heat stress. This intracellular stress stimulates the cell wall integrity (CWI) and high-osmolarity glycerol (HOG) MAPK pathways resulting in hyphal growth. If cell wall integrity is compromised, however, ZtMsr1 represses the hyphal development program and may induce the chlamydospore-inducing genes as a stress-response survival strategy. Taken together, these results suggest a novel mechanism through which morphological transitions are orchestrated in Z. tritici – a mechanism that may also be present in other pleomorphic fungi.

Incidence, Characterization and Pathogenic Variability of Fusarium oxysporum in the Punjab Province of Pakistan

The present studies were conducted to determine the incidence of wilt caused by Fusarium oxysporum in the major chili-growing districts of Punjab, characterization of Fusarium isolates, and assessment of their pathogenic variability. The overall incidence of Fusarium wilt in the five major surveyed districts of the Punjab province was 9.2% in the year 2015-16 and 9.3% in the year 2016-17. The maximum disease incidence of 10.04% was recorded in district Multan in the year 2015-16 while it was the minimum (7.06%) in district Sahiwal. A similar trend was observed in the disease incidences during the year 2016-17. The disease incidences varied among different localities of the five districts. In total, 92 isolates were recovered from the chili crop in Punjab. All the recovered purified isolates were morphologically characterized using different parameters like colony color, growth habit, pigmentation, days to fill 9-cm-dish, concentric rings, size and shape of macroconidia and microconidia, phialide, septation in macroconidia, diameter, and formation of chlamydospores and interseptal distance. All the isolates were confirmed as Fusarium oxysporum. Based on the pathogenicity test, plants showing more than 75% wilting were rated as highly pathogenic, plants showing 50.1-75% wilting were pathogenic, plants showing 25.1-50% wilting were categorized as moderately pathogenic, and plants showing 0.1-25% wilting were graded as weakly pathogenic. The highly pathogenic and pathogenic isolates were subjected to molecular studies and all the isolates made a band of 550-600 on the gel. All the isolates showed 99-100% similarity with already reported Fusarium species. The phylogenetic tree showed a close relationship between all the isolates

Grf10 regulates the response to copper, iron, and phosphate in Candida albicans.

The pathogenic yeast, Candida albicans, and other microbes must be able to handle drastic changes in nutrient availability within the human host. Copper, iron, and phosphate are essential micronutrients for microbes that are sequestered by the human host as nutritional immunity; yet high copper levels are employed by macrophages to induce toxic oxidative stress. Grf10 is a transcription factor important for regulating genes involved in morphogenesis (filamentation, chlamydospore formation) and metabolism (adenylate biosynthesis, 1-carbon metabolism). The grf10Δ mutant exhibited resistance to excess copper in a gene dosage-dependent manner but grew the same as the wild type in response to other metals (calcium, cobalt, iron, manganese, and zinc). Point mutations in the conserved residues D302 and E305, within a protein interaction region, conferred resistance to high copper and induced hyphal formation similar to strains with the null allele. The grf10Δ mutant misregulated genes involved with copper, iron, and phosphate uptake in YPD medium and mounted a normal transcriptional response to high copper. The mutant accumulated lower levels of magnesium and phosphorus, suggesting that copper resistance is linked to phosphate metabolism. Our results highlight new roles for Grf10 in copper and phosphate homeostasis in C. albicans and underscore the fundamental role of Grf10 in connecting these with cell survival.