Yeast Colonies Research Articles

Vulvovaginal candidiasis in pregnant women attending a tertiary care centre in North-Eastern India

BackgroundCandida colonisation in vagina was found to be 20 %, rising to 30 % during pregnancy. According to studies, the prevalence of VVC during pregnancy is higher than healthy women. During pregnancy, candidal colonisation increases, both symptomatic and asymptomatic. However, the difference between strains causing symptomatic infection and those that cause asymptomatic infection is unknown. ObjectiveThis study aimed to compare the virulence factors of Candida VVC isolates from symptomatic and asymptomatic pregnant women. MethodsThe study included 120 pregnant women- 60 symptomatic and 60 asymptomatic, who presented to the Obstetrics and Gynaecology Outpatient Department with vaginitis symptoms. High vaginal swabs from the patient and used for gram stain, direct wet mount, pH detection and fungal culture in SDA with and without antibiotics. Germ tube tests, growth in CMA, and HiCrome Candida Differential Agar were used to identify yeast colonies grown in culture. The isolates were then examined for virulence factors like biofilm formation, phospholipase, coagulase, and hemolysin. Antifungal susceptibility was determined using E-test. ResultsThe current study reveals a high prevalence of Vulvovaginal Candidiasis in pregnant women(35 %). Asymptomatic patients had lower proportion of VVC than symptomatic patients. Non albicans Candida(NAC) outnumbered Candida albicans. Although Candida albicans growth was predominant in asymptomatic patients. Virulence studies revealed that Candida spp. isolated from symptomatic patients expressed a higher proportion of virulence factors. Besides NAC has higher proportion of expressing virulence factors than Candida albicans and has higher propensity to cause infection especially in symptomatic pregnant women. Antifungal susceptibility testing shows Itraconazole to be most sensitive for VVC treatment but Candida albicans was most susceptible to fluconazole while NAC had the least. ConclusionsThe study emphasizes the importance of routine screening of symptomatic pregnant women for VVC, as syndromic treatment will increase antifungal resistance, particularly in NAC.

High-efficiency expression of alginate lyase in Pichia pastoris facilitated by Vitreoscilla hemoglobin

Vitreoscilla hemoglobin (VHb) can enhance the ability of recombinant strains to express heterologous proteins under low-oxygen conditions. However, its mechanism of action in the Pichia pastoris expression system remains unclear. In this study, three VHb construction strategies were designed to elucidate the mechanisms by which VHb promotes heterologous protein expression in P. pastoris. Notably, the co-expression pattern involving the sequential expression of the 102C300C gene followed by the Vgb gene significantly improved enzyme activity in the recombinant strain X33-102C300C-Vgb. The enzyme activity was 203.4 ± 0.57 U/mL at 180 h of fermentation in the 5-L system, which was 20.7 % higher than that of the starting strain X33-102C300C. Fluorescent labeling experiments revealed for the first time that a dual-transcription unit approach achieved superior VHb expression, indicating its potential for further development. Furthermore, transcriptomic and metabolomic analyses demonstrated that VHb enhances the growth of recombinant yeast colonies by improving respiration-related metabolism under low-oxygen conditions. This, in turn, alleviated the repression of the expression alcohol oxidase (AOX) at high methanol concentrations, resulting in increased alginate lyase activity. This study provides a theoretical foundation for improving the target protein expression in recombinant P. pastoris during high-density fermentation.

Analysis of Phenolic Content in Green Tea Kombucha and Rosella (Hibiscus sabdariffa) Kombucha Using Spectrophotometer Uv-Vis

Phenolic compounds are compounds that have hydroxyl groups and are most abundant in plants. Green tea and rosella flowers are types of plants that contain phenolic compounds and can be used as ingredients to make kombucha tea drinks. Kombucha is a fermented drink made from tea and sugar which is fermented by a colony of bacteria and yeast. The aim of this research was to determine the levels of phenolic compounds in green tea kombucha and rosella flowers through experimental tests using spectrophotometry uv-vis. The results showed that the phenolic content of green tea kombucha was 162.35 mg/L GAE, while rosella kombucha had a level of 101.30 mg/L GAE. Thus, the phenolic content of green tea kombucha is higher compared to rosella kombucha.

Live-cell analysis of IMPDH protein levels during yeast colony growth provides insights into the regulation of GTP synthesis.

This study used live-cell microscopy to track changes in the level of a key enzyme in GTP nucleotide biosynthesis, inosine monophosphate dehydrogenase (IMPDH), during growth of a brewers yeast colony over 2 days in a microfluidic device. The results show that feedback regulation via transcription attenuation allows cells to adapt to nutrient limitation in the crowded environs of a yeast colony. They also identify a novel mode of regulation of IMPDH level that is not driven by guanine nucleotide availability.

Design of a Multiparametric Biosensing Platform and Its Validation in a Study on Spontaneous Cell Detachment from Temperature Gradients.

This article reports on a bioanalytical sensor device that hosts three different transducer principles: impedance spectroscopy, quartz-crystal microbalance with dissipation monitoring, and the thermal-current-based heat-transfer method. These principles utilize a single chip, allowing one to perform either microbalance and heat transfer measurements in parallel or heat transfer and impedance measurements. When taking specific precautions, the three measurement modalities can even be used truly simultaneously. The probed parameters are distinctly different, so that one may speak about multiparametric or "orthogonal" sensing without crosstalk between the sensing circuits. Hence, this sensor allows one to identify which of these label-free sensing principles performs best for a given bioanalytical application in terms of a high signal amplitude and signal-to-noise ratio. As a proof-of-concept, the three-parameter sensor was validated by studying the spontaneous, collective detachment of eukaryotic cells in the presence of a temperature gradient between the QCM chip and the supernatant liquid. In addition to heat transfer, detachment can also be monitored by the impedance- and QCM-related signals. These features allow for the distinguishing between different yeast strains that differ in their flocculation genes, and the sensor device enables proliferation monitoring of yeast colonies over time.

КОМБИНИРОВАННЫЕ ТВОРОЖНО-ОВОЩНЫЕ ЗАПЕКАНКИ ИЗ МЕСТНОГО СЫРЬЯ ДЛЯ РАЦИОНАЛЬНОГО ПИТАНИЯ

The aim of the study is to develop a recipe for combined curd-vegetable casseroles from local raw materials with improved organoleptic and physicochemical properties. A comprehensive study was conducted that allowed theoretically and experimentally substantiating the feasibility of using turnips as a functional ingredient in the preparation of curd-vegetable casserole. The following quality indicators were studied in the experimental samples of culinary products: mass fraction of fat, protein, total sugars, ascorbic acid content; sanitary and microbiological indicators: the number of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), the number of yeast and mold fungi, and coliform bacteria (BGCP). The applied research methods are the mass fraction of fats according to GOST 31902-2012, the mass fraction of protein by the Kjeldahl method according to GOST 10846-91, the mass fraction of ascorbic acid was determined by titration with a solution of sodium 2,6-dichlorophenolindophenolate according to GOST 24556-89, the mass fraction of sugars – by the iodometric method, by diluting the sanitary and microbiolo¬gical indicators of QMAFAnM according to GOST 10444.15-94, counting the colonies of mold fungi and yeast according to GOST 10444.12-2013 and coliform bacteria according to GOST 31747-2012. The study was carried out at the Department of Public Catering Technology and Processing of Plant Raw Materials of the Federal State Budgetary Educational Institution of Higher Education "BashSAU", Republic of Bashkortostan. In the recipe for making cottage cheese and vegetable casserole, carrots were replaced with turnips in a ratio of 25 to 100 %. It was found that 100 % replacement of carrots with turnips in a culinary product improves organoleptic properties (taste, color) and physicochemical indicators (increase in vitamin C by 5.5 times). Sanitary and microbiological indicators (QMAFAnM, coliform bacteria, yeast and mold) corresponded to the required SanPiN 2.3.2.1078-01 standards.

Impact of using yeast derivatives on the development of atypical aging in wines

Yeast derivatives (YDs) are commercial products obtained from yeast colonies grown in bioreactors then inactivated and dried. They are employed in winemaking to supply nitrogen (N), enhance yeast growth and remove unwanted compounds. Since glucose is the primary carbon and energy source for yeast growth, agricultural byproducts are commonly used in their production. Atypical aging (ATA) is a wine aroma defect arising from the oxidation of indole-3-acetic acid (IAA) to 2-aminoacetophenone (AAP). It entails the appearance of unpleasant odours as well as the rapid loss of varietal aromas. As IAA is one of the main plant hormones and YDs are often manufactured using material of plant origin, it can be assumed that AAP precursors are contained in those commercial formulations. If this is the case, the use of YDs could potentially increase the risk of obtaining ATA-tainted wines. To explore this hypothesis, 28 YDs were screened for the presence of AAP-related compounds, as well as their amino acidic content. Since several ATA precursors were detected, fermentation experiments were carried out in which different amounts of YD were added to different grape musts. Interestingly, depending on the nature of the commercial formulation, AAP development was observed to be either enhanced or diminished. More specifically, as well as concentration of AAP and precursors, the presence of cell walls within the YDs seemed to have an influence on the development of this defect. Furthermore, as diammonium phosphate (DAP) is also used to provide grape must with N, the effect of supplementing must with DAP was investigated. The addition of increasing doses of DAP did not significantly affect the accumulation of AAP. These results are very promising for both winemakers and YD producers, and they highlight the need for further research on the use of YDs in oenology.

Investigating the Influence of Temperature and Supplementation Timing on Antifungal Efficacy in Storage Medium for Corneal Transplantation.

Although antifungal supplementation reduces the fungal load in the corneal storage medium, consensus is lacking on the influence of dosing and temperature. The study aims to evaluate the impact of eye bank warming protocol and timing of antifungal supplements on efficacy in Optisol-GS and tissue. Corneoscleral rims contaminated with Candida albicans (C.albicans) were incubated in Optisol-GS, either without antifungal agents or with the addition of amphotericinB or voriconazole at various concentrations (2 ×, 5 ×, 10 ×, and 20 × MIC), at different time points, and under various preservation temperatures (2-8°C versus 2h-room temperature exposure). Antifungal efficacy was evaluated by counting viable yeast colonies cultured from Optisol-GS samples. Tissue sterility was determined through direct tissue culture and histological examination of the contaminated rims after a 14-day incubation period. Room temperature exposure did not increase colony growth at the same multiple MIC of antifungal agents. Although antifungal addition reduced C.albicans growth in a concentration-dependent manner, yeast growth was still observed in all Optisol-GS samples with a single supplementation after a 14-day incubation. Only groups with additional antifungal supplementation on either day2 or day6 showed a 99% or greater reduction of C.albicans growth in Optisol-GS samples and yielded negative results in direct tissue culture. The eye bank warming protocol did not compromise antifungal efficacy. To sustain the required concentration and effectively reduce C.albicans growth in Optisol-GS and contaminated tissue, additional antifungal supplementation on either day2 or day6 was necessary during a 2-week preservation period.

GpEF1A: a novel lysine methyltransferase gene from Gypsophila perfoliata L. involved in boron homeostasis.

Rapid accumulation of boron (B) leads to toxicity in plant tissues, and the narrow gap between deficiency and toxicity makes it difficult to adjust essential B levels in soil for plant productivity. Therefore, understanding different aspects of B tolerance is necessary to provide new and valid solutions to B toxicity. Gypsophila perfoliata stands out as a remarkable example of a B-tolerant plant, with a natural propensity to thrive in environments such as B mines and soils enriched with high levels of B. In this study, a yeast functional screening experiment was conducted using cDNA libraries from G. perfoliata leaf and root cells for B tolerance. Ten colonies from the leaf library grew in 80 mm boric acid, while none emerged from the root library. Analysis of isolated cDNAs showed identical sequences and a unique motif related to B tolerance. The gene GpEF1A was identified in the tolerant yeast colonies, with predicted structural features suggesting its role, and RT-qPCR indicating increased expression under B stress. A regulatory role for EF1A lysine methylation was proposed in mammalian cells and fungi because of its dynamic and inducible nature under environmental constraints. This could also be relevant for plant cells, as the high similarity of the GpEF1A gene in some salt-tolerant plants might indicate the upregulation of EF1A as a conserved way to cope with abiotic stress conditions. This report represents the first instance of involvement of GpEF1A in B tolerance, and further detailed studies are necessary to understand other components of this tolerance mechanism.

The homeodomain of the <i>Raphanus sativus</i> WOX4 binds to the promoter of the <i>LOG3</i> cytokinin biosynthesis gene

BACKGROUND: The WOX4 transcription factor plays a crucial role in maintaining the organisation of cambium meristem during secondary growth, but its direct targets are unknown. AIM: The aim of our work were to study the effect of WOX4 overexpression on the root development and gene expression in radish (Raphanus sativus L.), a root crop related to Arabidopsis thaliana, and to search for direct targets of the WOX4 in radish. MATERIALS AND METHODS: Radish line 19 of the St. Petersburg State University radish genetic collection was used. Plants were grown on Murashige–Skoog medium and then in soil at 23оС and 16 h of daylight. Total DNA was extracted from radish seedlings using the CTAB method. The PCR-amplified full-length RsWOX4-2 gene, gene fragments or homeobox sequence were cloned into the vectors for overexpression (pB7WG2D), RNA interference (pH7GWIWG2) and yeast one-hybrid assay (pDEST22), respectively, using the Gateway system. The vectors for overexpression and RNA interference of RsWOX4-2 were transformed into Escherichia coli DH10B and then into Agrobacteium rhizogenes Arqua chemically competent cells. Radish seedlings were transformed with A. rhizogenes containing vectors for overexpression and RNA interference of RsWOX4-2, and GUS-overexpressing A. rhizogenes was used as a control. Total RNA from transgenic radish roots was extracted with Trizol reagent. RNA reverse transcription was performed using dT-18 primers and RevertAid reverse transcriptase. qPCR was performed using the Eva Green reagent kit on a CFX96 thermocycler with fluorescence detection system. Results were processed using the 2–ΔΔCT method. Yeast transformation was performed using the competent Saccharomyces cerevisiae cells of Y2H Gold strain. For the yeast one-hybrid assay, the obtained yeast colonies transformed with plasmids containing TF homeodomain sequence and promoter regions of genes were grown on DDO and TDO selective media with different concentrations of 3-amino-1,2,4-triazole. Statistical processing based on Student’s t-test and graphing were performed using the ggplot2 package for the R programming language (v.4.0.2). RESULTS: Overexpression of the RsWOX4-2 gene affects the structure of the radish root stele and alters the number of vessels and cambium cells. Overexpression and RNA interference of the RsWOX4-2 causes changes in the expression levels of putative target genes with the WOX family transcription factor conserved binding sites in their promoters. Using the yeast one-hybrid assay, we have shown that the DNA-binding homeodomain of RsWOX4-2 interacts with the TAATCC site in the promoter of the RsLOG3 gene, which encodes the enzyme for cytokinin biosynthesis. CONCLUSIONS: We have demonstrated the effect of RsWOX4-2 overexpression on radish root stele and gene expression and identified the RsLOG3 as the putative direct target of the WOX4 transcription factor in radish.

Comparison of time-to-detection of Mindray TDR and BacT/ALERT®3D blood culture systems using simulated blood cultures

ABSTRACT Purpose Blood culture (BC) is the standard for diagnosing bloodstream infections. Available blood culture (BC) systems have been developed to shorten the time to detection (TTD) of positive BCs. This study aimed to evaluate the performance of the Mindray TDR automatic BC system by comparing it with the BacT/ALERT®3D system. Methods Sixteen reference strains and 14 clinical isolates were used. Serial dilutions were prepared from all bacterial and yeast colonies with a final concentration of 100 CFU/ml and 10 CFU/ml. The prepared solutions were simultaneously inoculated into the bottles of both systems and placed in blood culture devices. Results Three hundred and fifty-two (176 BacT/ALERT®3D and 176 Mindray TDR-X060) blood culture bottles were evaluated, 336 aerobic and 16 anaerobic. At both 10 CFU/ml and 100 CFU/ml dilution, there was no significant difference between the two systems in terms of mean detection times for all isolates (p = 0.965, p = 0.245). When evaluated according to the type of organism, the detection time of gram-positive bacteria at 10 CFU/ml dilution was significantly shorter in the BacT/ALERT system (p = 0.019), whereas detection time for yeasts was significantly shorter with the Mindray system (p = 0.047). The number of anaerobic bacteria was too small to draw statistical conclusions, but we observed a trend of shorter detection times in the Mindray TDR-X060 system. Conclusion Two systems with similar operating principles showed different concentrations-dependent performances in terms of positivity detection times depending on the type of microorganism. Mindray TDR-X060 system has been found to be safe to use at high concentrations with this at lower concentrations further comparative studies are needed on the newly introduced Mindray system.

Integrative analysis of yeast colony growth

Yeast colonies are routinely grown on agar plates in everyday experimental settings to understand basic molecular processes, produce novel drugs, improve health, and so on. Standardized conditions ensure these colonies grow in a reproducible fashion, while in nature microbes are under a constantly changing environment. Here we combine the power of computational simulations and laboratory experiments to investigate the impact of non-standard environmental factors on colony growth. We present the developement and parameterization of a quantitative agent-based model for yeast colony growth to reproduce measurements on colony size and cell number in a colony at non-standard environmental conditions. Specifically, we establish experimental conditions that mimic the effects of humidity changes and nutrient gradients. Our results show how colony growth is affected by moisture changes, nutrient availability, and initial colony inoculation conditions. We show that initial colony spread, not initial cell number have higher impact on the final size and cell number of colonies. Parameters of the model were identified by fitting these experiments and the fitted model gives guidance to establish conditions which enable unlimited growth of yeast colonies.

Differential stability of Gcn4p controls its cell-specific activity in differentiated yeast colonies.

Gcn4p belongs to conserved AP-1 transcription factors involved in many cellular processes, including cell proliferation, stress response, and nutrient availability in yeast and mammals. AP-1 activities are regulated at different levels, such as translational activation or protein degradation, which increases the variability of regulation under different conditions. Gcn4p activity in unstructured yeast liquid cultures increases upon amino acid deficiency and is rapidly eliminated upon amino acid excess. Gcn2p kinase is the major described regulator of Gcn4p that enables GCN4 mRNA translation via the uORFs mechanism. Here, we show that Gcn4p is specifically active in U cells in the upper regions and inactive in L cells in the lower regions of differentiated colonies. Using in situ microscopy in combination with analysis of mutants and strains with GFP at different positions in the translational regulatory region of Gcn4p, we show that cell-specific Gcn4p activity is independent of Gcn2p or other translational or transcriptional regulation. Genetically, biochemically, and microscopically, we identified cell-specific proteasomal degradation as a key mechanism that diversifies Gcn4p function between U and L cells. The identified regulation leading to active Gcn4p in U cells with amino acids and efficient degradation in starved L cells differs from known regulations of Gcn4p in yeast but shows similarities to the activity of AP-1 ATF4 in mammals during insulin signaling. These findings may open new avenues for understanding the parallel activities of Gcn4p/ATF4 and reveal a novel biological role for cell type-specific regulation of proteasome-dependent degradation.IMPORTANCEIn nature, microbes usually live in spatially structured communities and differentiate into precisely localized, functionally specialized cells. The coordinated interplay of cells and their response to environmental changes, such as starvation, followed by metabolic adaptation, is critical for the survival of the entire community. Transcription factor Gcn4p is responsible for yeast adaptation under amino acid starvation in liquid cultures, and its activity is regulated mainly at the level of translation involving Gcn2p kinase. Whether Gcn4p functions in structured communities was unknown. We show that translational regulation of Gcn4p plays no role in the development of colony subpopulations; the main regulation occurs at the level of stabilization of the Gcn4p molecule in the cells of one subpopulation and its proteasomal degradation in the other. This regulation ensures specific spatiotemporal activity of Gcn4p in the colony. Our work highlights differences in regulatory networks in unorganized populations and organized structures of yeast, which in many respects resemble multicellular organisms.

Влияние геотермальной воды в составе твердых сред культивирования на морфологические свойства дрожжей рода Saccharomyces

The influence of geothermal waters located on the territory of the city of Makhachkala (Republic of Dagestan), in the composition of solid cultivation media, on the cultural and morphological features of genus Saccharomyces yeast was studied. Changes in cell properties and the formation of specific parameters of giant yeast colonies S. cerevisiae Y-503, S. cerevisiae DAW-3a, S. oviformis M-12x have been established. For YPD and PD media, as a result of a series of experiments, optimal options were selected containing geothermal and distilled water in a ratio of 1:1 (well No. 36) and 2:1 (well No. 26). It was shown that the YPD medium was optimal for yeast growth, while in the population of the tetraploid Y-503 strain, the average cell size was slightly larger than cell strain M-12x and significantly exceeded the DAW-3a values. Installed that the use of diluted water from well No. 36 in the cultivation medium is most effective and leads to accelerated growth of yeast colonies. In the variant geothermal / distilled water, this indicator exceeded the control by 1.3 (Y-503, M-12x) times; in the variant with geothermal water without dilution - by 1.6 (Y-503) and 1.4 (M-12x) times. The cells of the S. cerevisiae Y-503 strain, regardless of the medium used, are characterized by the presence of various forms, including elongated ones; DAW-3a - exceptionally rounded; S. oviformis M-12x - rounded and oval shapes. A comparative analysis of the parameters of the colonies showed that all variants are characterized by a rounded shape, a radially striated surface; flat, with a convex center profile; light beige color and pasty, spreadable texture. As a result of our research, a modified nutrient medium PD has been developed - an agar for growing yeast, containing geothermal water from well No. 36 of the Makhachkala field as an additional source of mineral and organic compounds. The proposed composition of the medium is of interest for its further use in microbiological studies.

Yeast Diversity in Honey and Pollen Samples from Stingless Bees in the State of Bahia, Brazil: Use of the MALDI-TOF MS/Genbank Proteomic Technique.

(1) Background: The identification of microorganisms includes traditional biochemical methods, molecular biology methods evaluating the conserved regions of rRNA, and the molecular biology of proteins (proteomics), such as MALDI-TOF MS mass spectrometry. This work aimed to identify the biodiversity of yeasts associated with stingless bee species' honey and pollen, Melipona scutellaris, Nannotrigona testaceicornes, and Tetragonisca angustula, from the region of São Gonçalo dos Campos-Bahia (BA) state, Brazil. (2) Methods: Cellular proteins were extracted from 2837 microbial isolates (pollen and honey) and identified via MALDI-TOF MS. The identified yeast species were also compared to the mass spectra of taxonomically well-characterized reference strains, available from the National Center of Biotechnology Information (NCBI) database. (3) Results: Nine yeast species were identified: Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Brettanomyces bruxellensis, Kazachstania exigua, and Starmerella lactis-condensi. Nannotrigona testaceicornes pollen had the highest number of yeast colonies. The yeasts Brettanomyces bruxellensis and Kazachstania telluris showed high populations in the samples of Nannotrigona testaceicornes and Melipona scutellaris, respectively. This work shows that there is some sharing of the same species of yeast between honey and pollen from the same beehive. (4) Conclusions: A total of 71.84% of the identified species present a high level of confidence at the species level. Eight yeast species (Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Kazachstania exigua, and Starmerella lactis-condensi) were found for the first time in the samples that the authors inspected. This contributes to the construction of new knowledge about the diversity of yeasts associated with stingless bee products, as well as to the possibility of the biotechnological application of some yeast species.

Morphology, Development, and Pigment Production of Talaromyces marneffei are Diversely Modulated Under Physiologically Relevant Growth Conditions.

Talaromyces marneffei is an opportunistic pathogenic fungus that mainly affects HIV-positive individuals endemic to Southeast Asia and China. Increasing efforts have been made in the pathogenic mechanism and host interactions understanding of this pathogen in the last two decades; however, there are still no conclusions on how T. marneffei was transmitted from the donor bamboo rats to humans. A perception that the failure of fungus isolation from soil was attributed to the low salt tolerance of T. marneffei. Therefore, the effect of environmental fluctuations in fungal growth and development is fundamental for the characterization of its origin and fungal biology understanding. Herein, we characterized high osmolarity, pH, metal ions, nutrients, and oxidative stress have versatile effects on T. marneffei hyphal or yeast growth, conidia generation, and pigment production. Among these, high pH, low glucose amounts, and the inorganic nitrogen ammonium tartrate stimulated the red pigment production, whereas high osmolarity, high pH, and the inorganic nitrogen sodium nitrate could significantly accelerate the conidia generation. Specifically, zinc starvation repressed conidia generation and prevented the wrinkled yeast colony formation, indicating the function of zinc regulators in pathogenicity regulation. Since conidia are recognized as the infectious propagules, the effects characterization of different environmental factors in T. marneffei morphology in this work will not only expand the growth and pathogenic biology understanding of the fungus but also provide more clues for the T. marneffei infection transmission origin investigation.

Comparison of The Effect of Candida Score and Candida Colonization Index on Decrease in Candidemia Incidence in Our Intensive Care Unit

Aim: Since candidemia is an important cause of mortality and morbidity in hospitals, especially in intensive care units (ICU), those hospitalized in the ICU; In patients with risk factors such as invasive device use and undergoing abdominal surgery, early empirical antifungal therapy is recommended to reduce mortality according to the results of candida score (CS) and candida colonization index (CCI). In this study, the data of the patients who were followed up in the ICU, who were started on empirical treatment according to KS and CCI, were evaluated and their effects on the incidence of candidemia were analyzed. Method: Cultures taken from 100 patients hospitalized in the intensive care unit where adult patients were followed between 01.06.2018 and 01.08.2021 were examined. While investigating the colonization index of each patient, swab samples were taken once during the hospitalization from five main sites: mouth, nose, skin, perineum, and catheter. Samples taken with sterile swabs were inoculated on Sabouraud dextrose agar (SDA) plates and the plates were incubated at 35°C for 48 hours. The yeast colonies formed were defined according to their microscopic appearance and biochemical properties. CCI and CS of the patients were evaluated and fluconazole prophylaxis was started in patients with KS ≥3 or CCI ≥0.5. Results: A total of 500 culture samples from 100 non-neutropenic adult patients were analyzed (Mean of 5 cultures/patient). No growth was detected in any of the samples in 32 (32 %) of 100 patients, and growth was detected in at least one of the samples taken from 68 patients (68 %). Reproduction was detected from a total of 118 samples. Of the yeasts, 104 were identified as Candida albicans, 10 as Candida glabrata and 4 as Candida inconspicua. CS≥ 3 and CCI ≥0.5 in 11 (11%) patients, and CS≥3, CCI

Analysis of candidemia cases in a city hospital during the COVID-19 pandemic.

The frequency and mortality of candidemia remain important. Non-albicans Candida species such as C. auris are increasing. A retrospective review of adult patients diagnosed with bloodstream infection due to Candida species in the 17 months between July 1, 2020, and December 1, 2021, was performed. Yeast colonies grown in culture were identified by matrix-assisted laser desorption/ionization time-of-flight. Antifungal susceptibility tests of Candida strains were performed with Sensititre YeastOne (TREK Diagnostic Systems Inc., Westlake, Ohio) kits, and minimum inhibitory concentration values were evaluated according to the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints. In total, 217 patients (mean age 64.9±15.7 years) were included. C. albicans was the most common fungus (detected in 82 patients; 37.8%), followed by C. parapsilosis (17.1%), C. glabrata (15.2%), C. tropicalis (15.2%), and C. auris (9%). Candidemia developed in 175 (81.4%) of the cases during their intensive care unit stay. Fluconazole (41.0%) and caspofungin (36.4%) were the two most frequently used antifungal agents in antifungal therapy. There were 114 (52.3%) deaths in the study group. Mortality rates were found to be lower in patients infected with C. parapsilosis or C. auris. Age and previous COVID-19 infection were other important risk factors. When the 217 Candida spp. were examined, resistance and intermediate susceptibility results were higher when EUCAST criteria were used. While the two methods were found to be fully compatible only for fluconazole, a partial agreement was also observed for voriconazole. As our study observed, the COVID-19 pandemic brought increasing numbers of immunosuppressed patients, widespread use of antibacterials, and central venous catheters, increasing the frequency and mortality of candidemia cases. All health institutions should be prepared for the diagnosis and treatment of candidemia. In addition, C. auris, the frequency of which has increased in recent years, is a new factor that should be considered in candidemia cases.

An Integrated Undergraduate Laboratory Exercise to Demonstrate Microbial Evolution

Understanding that evolution progresses through generation of DNA variants followed by selection is a key learning outcome for biology students. We designed an integrated and innovative undergraduate laboratory exercise using Saccharomyces cerevisiae to demonstrate these principles. Students perform in vitro experimental evolution by repeatedly propagating large or small yeast colonies on a weekly basis. Small-colony variants known as petites arise by mutations that disrupt aerobic respiration. To demonstrate the effects of increased mutation rates, half of the selection lines are exposed to ultraviolet irradiation. To understand how the petite phenotype arises, polymerase chain reaction (PCR) is performed to examine mitochondrial DNA, while biochemical assays are used to assess the ability of petites to undergo aerobic respiration. This exercise demonstrates evolution by artificial selection over a suitably short timeframe and links the results to a critical biochemical process: the role of mitochondria in aerobic respiration and ATP production. By implementing these experiments, we successfully demonstrated that the frequencies of petite mutants in evolved populations varied according to the selection pressure we applied, and that petite mutants carried deletions in mitochondrial DNA as anticipated. Through an integrated learning context, this practical exercise promotes fundamental understanding of evolutionary processes and fosters critical thinking skills.

Instant Candida albicans Detection Using Ultra-Stable Aptamer Conjugated Gold Nanoparticles.

Fungal pathogens such as Candida albicans have significant impacts on women's health and the economy worldwide. Current detection methods often require access to laboratory facilities that are costly, inconvenient, and slow to access. This often leads to self-diagnosis, self-treatment and eventual antifungal resistance. We have created a rapid (within five minutes), cost-effective, and user-friendly method for the early detection of Candida albicans. Our platform utilises aptamer-tagged-gold-core-shell nanoparticles for Candida albicans detection based on the presence of 1,3-β-d glucan molecules. Nanoparticle aggregation occurs in the presence of Candida albicans fungal cells, causing a redshift in the UV-visible absorbance, turning from pink/purple to blue. This colour change is perceptible by the naked eye and provides a "yes"/"no" result. Our platform was also capable of detecting Candida albicans from individual yeast colonies without prior sample processing, dilution or purification. Candida albicans yeast cells were detected with our platform at concentrations as low as 5 × 105 cells within a 50 μL sample volume. We believe that this technology has the potential to revolutionise women's health, enabling women to test for Candida albicans accurately and reliably from home. This approach would be advantageous within remote or developing areas.