Talaromyces oaxaquensis sp. nov. section Talaromyces (Trichocomaceae, Eurotiales) isolated from pseudostems of banana plants in Mexico

Rhynchosporium alismatis is a fungal pathogen that promises to be a suitable biological control agent to manage the rice weed, starfruit (Damasonium minus). Light and scanning electron microscopy were used to study the infection process. Conidial germination, appressorium formation, and penetration by R. alismatis were compared at 25 and 30°C on starfruit leaves, and in separate experiments, conidial germination and appressorium formation were compared at both temperatures on cellophane paper. Appressorium formation was significantly (P < 0.005) higher at 25 than 30°C after 8 h on leaves and after 10 h on cellophane paper. Sessile appressoria were frequently observed on leaves, while no such structures were observed on cellophane paper. Penetration through stomata appeared to be a random event. Subepidermal hyphae were frequent after 24 h, and conidial formation was observed 48 h after inoculation of leaves at 25°C. Deformation of the leaf surface around the appressoria indicated signs of physical pressure. Fast conidial germination, penetration, and infection is an advantage, since the fungus is not exposed for long periods of time to adverse environmental conditions. The formation of conidia on the leaves can lead to further disease spread.

The opportunistic pathogenic fungus, Trichosporon asahii easily causes rare skin and disseminated infections in the skin and internal organs in immunocompromised patients, particularly, those with AIDS or cancer or those who have received organ transplant are also susceptible to T. asahii infection. In this study, we monitored theeffects of three oxidants exposure to hydrogen peroxide, diamide and menadione on growth and development of a clinical isolate and an environmental isolate of T. asahii in vitro, obtained commercially. Growth of cultures was monitored in potato-dextrose agar (PDA) medium or yeast extract-peptone-dextrose (YPD) liquid medium containing increasing concentrations of the above oxidants. Cell and colony morphologies of these cultures were recorded by light microscopy and scanning electron microscopy (SEM), respectively. A concentration-dependent decrease in growth and colony diameter was seen in the presence of with oxidants concentration increase. The three oxidants all had the effect of inhibition and destruction of T. asahii. Under the same concentrations, the killing effect of three oxidants to T. asahii was different; menadione was strongest, followed by diamide and hydrogen peroxide was the weakest (compared with clinical isolate, the environmental isolate was more sensitive to the oxidants. All the three oxidants made the changes to T. asahii’s morphosis and structure, which resulted in its hypoplasia, aplasia and morphological conversion; menadione had stronger damaging effect. The average cell and colony diameter of the environmental isolate was smaller than that of the clinical isolate under the control conditions and it was comparatively more sensitive to the oxidants. In cultures of both isolates, exposure to oxidants resulted in concentration-dependent development delays, reduction in the number hyphae and of germ tubes, conversion of wrinkled surface to smooth surface, spore hypoplasia, and occasionally cytoplasm shrinkage seen in larger spores. Among the three oxidants tested, menadione had a comparatively higher damaging effect. Key words: Trichosporon asahii, oxidant, morphology.

Immunity is an important biological trait that influences the survival of individuals and the fitness of a species. Immune defenses are costly and likely compete for energy with other life-history traits, such as reproduction and growth, affecting the overall fitness of a species. Competition among these traits in scleractinian corals could influence the dynamics and structural integrity of coral reef communities. Due to variability in biological traits within populations and across species, it is likely that coral colonies within population/species adjust their immune system to the available resources. In corals, the innate immune system is composed of various pathways. The immune system components can be assessed in the absence (constitutive levels) and/or presence of stressors/pathogens (immune response). Comparisons of the constitutive levels of three immune pathways (melanin synthesis, antioxidant and antimicrobial) of closely related species of Scleractinian corals allowed to determine the link between immunity and reproduction and colony growth. First, we explored differences in constitutive immunity among closely related coral species of the genus Meandrina with different reproductive patterns (gonochoric vs. hermaphrodite). We then compared fast-growing branching vs. slow-growing massive Porites to test co-variation between constitutive immunity and growth rates and morphology in corals. Results indicate that there seems to be a relationship between constitutive immunity and sexual pattern with gonochoric species showing significantly higher levels of immunity than hermaphrodites. Therefore, gonochoric species maybe better suited to resist infections and overcome stressors. Constitutive immunity varied in relation with growth rates and colony morphology, but each species showed contrasting trends within the studied immune pathways. Fast-growing branching species appear to invest more in relatively low cost pathways of the immune system than slow-growing massive species. In corals, energetic investments in life-history traits such as reproduction and growth rate (higher energy investment) seem to have a significant impact on their capacity to respond to stressors, including infectious diseases and coral bleaching. These differences in energy investment are critical in the light of the recent environmental challenges linked to global climate change affecting these organisms. Understanding physiological trade-offs, especially those involving the immune system, will improve our understanding as to how corals could/will respond and survive in future adverse environmental conditions associated with climate change.

Species from within the Phytophthora cryptogea complex and related species, P. erythroseptica and P. sansomeana, readily hybridize

Sugarcane stem borer, Chilo venosatus Walker (Lepidoptera: Pyralidae) is a significant sugarcane pest in South China. Conidia or mycelia collected from the surface of sugarcane stem borer cadavers were cultured. The colony morphology, mycelia and conidial yield were observed with three-agar culture media: potato dextrose agar medium (PDA), potato dextrose with 1% (w/v) peptone agar medium (PPDA), and oatmeal agar medium (OMA). 16 different isolates were identified as Metarhizium anisopliae (Metschnikoff) based on macromorphological, micromorphological, and molecular characteristics, and PPDA was the better culture medium for vegetative growth and conidial yield (10 9 conidia/ml) than PDA (10 8 conidia/ml) and OMA (10 8 conidia/ml). To confirm whether these isolates were pathogenic to C. venosatus, their virulence to the sugarcane stem borer was tested in the laboratory. Both HS (10 isolates) and LY (6 isolates) strains were pathogenic to C. venosatus. Several highly virulent strains were screened in vitro (the mortalities of the eight isolates HS1, HS6, HS7, LY2, LY3, LY6, HS3 and HS9 were from 96 to 100%), and tests for controlling the sugarcane stem borer were preliminarily performed in vivo. The results show that significant (p=0.01) reductions in adult population were caused by the strains. So, M. anisopliae isolated from the cadavers of C. venosatus Walker is a potential biocontrol agent against this pest in South China.

Magnaporthe oryzae, the causal agent of the rice blast disease, poses a worldwide threat to stable rice production. The large-scale functional characterization of genes controlling the pathogenicity of M. oryzae is currently under way, but little is known about heat shock protein 40 (Hsp40) function in the rice blast fungus or any other filamentous plant pathogen. We identified 25 genes encoding putative Hsp40s in the genome of M. oryzae using a bioinformatic approach, which we designated M. oryzae heat shock protein forty (MHF 1-25). To elucidate the roles of these genes, we characterized the functions of MHF16 and MHF21, which encode type ill and type n Hsp40 proteins, respectively. MHF16 and MHF21 expression was not significantly induced by heat shock, but it was down-regulated by cold shock. Knockout mutants of these genes mhf16 and mhf21) were viable, but conidiation was severely reduced. Moreover, sectoring was observed in the mutant when it was grown on oatmeal agar medium. Conidial germination, appressorium formation, and pathogenicity in rice were not significantly affected in the mutants. The defects in conidiation and colony morphology were fully complemented by reintroduction of wild type MHF16 and MHF21 alleles, respectively. These data indicate that MHF16 and MHF21 play important roles in conidiation in the rice blast fungus.

Seventy seven oral swab samples (n=77) were collected in period between august 2007 to may 2008 from hospitalized immunocompromised and HIV patients suspected for Oropharyngeal Candidiasis and admitted in different hospitals in Ed-wiuem state and Khartoum state, Sudan. All samples were inoculated on Sabouraud dextrose agar and identified by colonial morphology, Germ tube test and Vitek2 compact system for biochemical identification and antifungal susceptibility test. Out of 77 oral swab samples collected from immunocompromised and HIV patients, 41 (53.3%) samples showed positive growth of Candida, and 36 (46.7%) samples showed negative growth. The identification showed that out of forty one positive cultures, 32 isolates found as Candida albicans (78%), while nine samples (n=9) appeared as non-Candida albicans (22%) and found as Candida lusitaniae according to GTT and Vitek2 Compact identification. Then DNA was extracted from all non-Candida albicans isolates and DNA sequencing was carried and D1/D2 region were determined using NL1 primer. DNA based identification showed that all nine (n=9) GTT negative isolates were Candida lusitaniae (Anamorh Clavispora lusitaniae). This study documented that there are new emergent species of Candida should be considered when dealing with specimen collected from patients suspected for yeast infections. Our results provide useful information that C. lusitaniae can be isolated as well as other Candida species from immunocompromised patients in Sudan.

Objectives: Invasive mold infections associated with Aspergillus species are a significant cause of mortality in immunocompromised patients. The most frequently occurring aetiological pathogens are members of the Aspergillus section Fumigati followed by members of the section Terrei. The frequency of Aspergillus terreus and related (cryptic) species in clinical specimens, as well as the percentage of azole-resistant strains remains to be studied.Methods: A global set (n = 498) of A. terreus and phenotypically related isolates was molecularly identified (beta-tubulin), tested for antifungal susceptibility against posaconazole, voriconazole, and itraconazole, and resistant phenotypes were correlated with point mutations in the cyp51A gene.Results: The majority of isolates was identified as A. terreus (86.8%), followed by A. citrinoterreus (8.4%), A. hortai (2.6%), A. alabamensis (1.6%), A. neoafricanus (0.2%), and A. floccosus (0.2%). One isolate failed to match a known Aspergillus sp., but was found most closely related to A. alabamensis. According to EUCAST clinical breakpoints azole resistance was detected in 5.4% of all tested isolates, 6.2% of A. terreus sensu stricto (s.s.) were posaconazole-resistant. Posaconazole resistance differed geographically and ranged from 0% in the Czech Republic, Greece, and Turkey to 13.7% in Germany. In contrast, azole resistance among cryptic species was rare 2 out of 66 isolates and was observed only in one A. citrinoterreus and one A. alabamensis isolate. The most affected amino acid position of the Cyp51A gene correlating with the posaconazole resistant phenotype was M217, which was found in the variation M217T and M217V.Conclusions: Aspergillus terreus was most prevalent, followed by A. citrinoterreus. Posaconazole was the most potent drug against A. terreus, but 5.4% of A. terreus sensu stricto showed resistance against this azole. In Austria, Germany, and the United Kingdom posaconazole-resistance in all A. terreus isolates was higher than 10%, resistance against voriconazole was rare and absent for itraconazole.

Early blight is most common and devastating disease in tomato plant caused by deuteromycotina fungi, Alternaria solani. This fungus grows well in potato dextrose agar and Richard’s broth medium in vitro. The growth of the fungi were tested under culture in twelve different liquid and solid media and compared with each other. Potato dextrose agar and oat meal agar among solid media and Richard’s broth and Sabouraud’s broth among liquid media appeared to be better than other media for growth of tomato early blight causing fungi. The growth characteristics such as color of colony and substrate, margin of colony, topography of mycelium along with the sporulation of the test fungus were studied on these solid media. Fungus sporulation was best in oat meal agar media. Maximum growth of the fungus was observed at 8 days after inoculation with continuous increasing growth in the potato dextrose broth (PDB) medium, although growth rate was decreasing after the 2 days of inoculation. This study will be helpful for further investigations on the physiology of the fungus and management of the disease. This investigation may be useful for taxonomic study of the fungus.

The conidiomata, conidiophores, and conidia of six lichen-forming Ascomycetes were investigated using the scanning electron microscope, and conidium development in two of these species was studied by transmission electron microscopy. Phialidic (micro) conidium formation was observed in the mycobiont of Parmelia tiliacea, Physconia pulverulacea, and Cladonia furcata (Lecanorales), in Lobaria laetevirens (Peltigerales), and in Caloplaca aurantia (Teloschistales). Annellations, first described by Vobis on the basis of light and transmission electron microscope investigations, were also found in scanning electron microscope preparations of macroconidia bearing conidiogenous cells of Lecanactis abietina (Opegraphales). Ultrastructural and developmental studies on conidiophore structure and conidium formation may be of interest for taxonomic and evolutionary considerations in lichen-forming fungi.

Scanning electron microscopy has been identified as an important approach in studying scale microstructures in fish with reference to taxonomy. In this article, a detailed microstructural analysis of the scales of Channa barca, a poorly known snakehead fish was carried out the location of focus, inter-radial distance, average width and inter-circular space of anterior circulii; inter-circular distance and dentition in lateral circulii; the shape, spacing, length of lepidonts in anterior circulii and the number and width of radii were compared with those of a related species, Channa aurantimaculata. The location of the focus was found to be similar to those of the gachua group of the genus Channa but was different from those of the marulius group. There were major similarities-though with a few notable differences-in scale microstructures between C. barca and the aforementioned closely related species C. aurantimaculata, indicating that scale microstructure analysis has the potential to distinguish even closely related fish species. While several of the microstructural features of the scale were found to be similar to those of the gachua group, others were closer in nature to those of the marulius group. Some microstructural characteristics, however, were found to be totally different from those of both gachua and marulius groups. All of these characteristic features of scale microstructure in C. barca are discussed with reference to taxonomic significance.

Lodderomyces elongisporus, first isolated in 1952, has increasingly been recognized as a significant pathogen, with a notable rise in human infections since the 1970s. Initially misidentified as Candida parapsilosis due to morphological similarities, L. elongisporus has now been conclusively established as a distinct species, largely due to advancements in molecular biology, particularly DNA sequencing. This review traces the detection history of L. elongisporus, from the earliest documented cases to the most recent reports, underscoring its role as a causative agent in human infections. It also explores therapeutic strategies that have demonstrated efficacy, alongside instances of environmental contamination reported in international literature. A critical evaluation of diagnostic methodologies essential for precise identification is provided, including culture-based techniques such as colony morphology on Sabouraud Dextrose Agar (SDA) and chromogenic media, coupled with microscopic assessments using Lactophenol Cotton Blue (LPCB) and Gram staining. The ultrastructure of L. elongisporus, as observed under Scanning Electron Microscopy (SEM), is also discussed. Furthermore, non-culture-based diagnostics, such as sugar utilization tests (API 20C AUX and the innovative in-house arabinose-based “Loddy” test) and antifungal susceptibility profiling, are reviewed, with a particular focus on molecular tools like ITS-DNA sequencing and MALDI-TOF MS, which, despite their higher costs, offer unparalleled specificity. The accurate distinction and characterization of L. elongisporus are paramount, particularly in vulnerable and immunocompromised patients, where misdiagnosis can lead to severe consequences. This review advocates for intensified research efforts to develop more accessible diagnostic tools and deepen our understanding of this emerging pathogen, ultimately aiming to improve patient outcomes.

Backrounds: This study aimed to evaluate the antimicrobial activities of glass ionomer luting cements modified with chlorhexidine diacetate. Methods: Chlorhexidine diacetate (CXD) was incorporated into glass ionomer luting powder at 0 %, 1 %, 2 %, 3 % concentration and 120 round-shaped samples were prepared. Antimicrobial properties against Streptococcus mutans (S. mutans), Enterococcus faecalis(E. faecalis), and Candida albicans (C. albicans) were assessed with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and Cristal Violet Assay. Biofilms on samples were also observed by Scanning Electron Microscopy. One-way ANOVA and Tukey Tests were used for statistical analysis. Results: The highest amount of antimicrobial activity was found in samples with 3 % added CXD. The proportion of viable pathogens were reduced significantly with the addition of 2 % and 3 % CXD (p &lt; 0.05). A noticeable reduction of S. mutans amount was seen with incorporation of 3 % CXD (p &lt; 0.05). S. mutans and C. albicans were inhibited significantly by all the samples when compared to control groups. Conclusions: Addition of 2 %- 3 % CXD to glass ionomer luting cements increased the antimicrobial properties. As, microorganisms’ growth rate was inhibited in 3% CXD group, CXD added glass ionomer luting cement can be suggested in endodontically treated teeth, in high caries-risk patients, also in immunocompromised patients.

The entomopathogenic fungi Beauveria bassiana (Bals.-Criv.) Vuill. 1912 (Hypocreales: Cordycipitaceae), thanks to its effective insecticidal properties, is widely used as a biological control agent. A critical issue in the mass-production of fungal-based biopesticides is the selection of the culture media optimal for the growth and sporulation of the producer strain. The most often used medium for the cultivation of B. bassiana is Potato Dextrose Agar (PDA). However, the relatively high price of the commercially available PDA medium determines the need to look for an alternative culture medium that would allow efficient and profitable cultivation of entomopathogenic strains for industrial purposes. Thus, the research aimed to select the optimal nutrient medium for mass-production of a local B. bassiana strain (Invention Patent MD 4560). The B. bassiana CNMN-FE-01 strain's vegetative growth was studied on several nutrient media for 14 days at a constant temperature of 25°C. In addition, the number of conidia produced per unit area and the germination rate of these conidia after cultivation on each media were determined. Of all analyzed media three represented commercially available formulations (PDA, SDA - Sabouraud Dextrose Agar, and SAPF Selective Agar for Pathogenic Fungi), and two were readymade formulations supplemented with yeast extract (SDAY and PDAY). The other were prepared in the laboratory according to known recipes (PSA Potato Sucrose Agar, PDA, PDAY, Oatmeal Agar). As a result, B. bassiana CNMN-FE-01 strain can be successfully cultivated on various solid media, commercially available formulations, and media prepared in the laboratory. The maximum radial growth rate of the micromycete was recorded on the Oatmeal Agar medium. Also, on Oatmeal Agar, the local strain produces the highest number of viable conidia. The experimental data indicate that the micromycete growth rate differs depending on the culture medium used. The same culture medium but from different producers can induce distinct growth and sporulation patterns of the fungal strain. The current work emphasizes the necessity to verify the purchased media and to identify a simple, cost-efficient media that can be easily prepared on site but also suggests the importance of setting the quality control points in the mass production of fungal-based biopesticides.

Algal food density is known to influence life history variables of cladoceran species. It is not, however, well established whether both littoral and planktonic cladocerans show similar trends when exposed to increasing food concentrations. In the present work, we studied the life table demography of four cladoceran species (Ceriodaphnia cornuta, Moina macrocopa, Pleuroxus aduncus and Simocephalus vetulus) in relation to three algal food concentrations (low: 0.5 × 106, medium: 1.5 × 106 and high: 4.5 × 106 cells ml−1 of Chlorella vulgaris) (in terms of carbon content, these were equivalent to 0.15, 0.45 and 1.35 μg ml−1, respectively) at 25 °C. In general, for all the tested cladoceran species, values of average lifespan, gross reproductive rate, net reproductive rate, generation time and the rate of population growth were higher at lower food concentrations. Furthermore, high food concentration resulted in a negative population growth rate (mean ± standard error: −0.091 ± 0.026) for P. aduncus. The highest population growth rate (0.602 ± 0.014) was recorded for M. macrocopa at low food density. S. vetulus had the longest average lifespan (40 ± 1 d) while M. macrocopa had the lowest (5 ± 1 d). C. cornuta showed better performance at medium food concentration. We conclude that among the algal concentrations used here, 0.5 × 106 – 1.5 × 106 was beneficial not only to the planktonic species but also to the littoral P. aduncus and S. vetulus while 4.5 × 106 cells ml−1 was unsuitable for all the cladocerans tested.