Isolation and Characterization of Chitosans from Different Fungi with Special Emphasis on Zygomycetous Dimorphic Fungus Benjaminiella poitrasii: Evaluation of Its Chitosan Nanoparticles for the Inhibition of Human Pathogenic Fungi.

The cell wall chitosan was extracted from fungi belonging to different taxonomic classes, namely, Benjaminiella poitrasii (Zygomycetes, dimorphic), Hanseniaspora guilliermondii, Issatchenkia orientalis, Pichia membranifaciens, and Saccharomyces cerevisiae (Ascomycetes, yeasts), and Agaricus bisporus and Pleurotus sajor-caju (Basidiomycetes). The maximum yield of chitosan was 60.89 ± 2.30 mg/g of dry mycelial biomass of B. poitrasii. The degree of deacetylation (DDA) of chitosan extracted from different fungi, as observed with 1H NMR, was in the range of 70-93%. B. poitrasii chitosan exhibited the highest DDA (92.78%). The characteristic absorption bands were observed at 3450, 1650, 1420, 1320, and 1035 cm-1 by FTIR. Compared to chitosan from marine sources (molecular weight, MW, 585 kDa), fungal chitosans showed lower MW (6.21-46.33 kDa). Further, to improve the efficacy of B. poitrasii chitosan (Bp), nanoparticles (Np) were synthesized using the ionic gelation method and characterized by dynamic light scattering (DLS). For yeast and hyphal chitosan nanoparticles (BpYCNp and BpHCNp), the average particle size was <200 nm with polydispersity index of 0.341 ± 0.03 and 0.388 ± 0.002, respectively, and the zeta potential values were 21.64 ± 0.34 and 24.48 ± 1.58 mV, respectively. The B. poitrasii chitosans and their nanoparticles were further evaluated for antifungal activity against human pathogenic Candida albicans ATCC 10231, Candida glabrata NCYC 388, Candida tropicalis ATCC 750, Cryptococcus neoformans ATCC 34664, and Aspergillus niger ATCC 10578. BpHCNps showed lower MIC90 values (0.025-0.4 mg/mL) than the chitosan polymer against the tested human pathogens. The study suggested that nanoformulation of fungal chitosan, which has low molecular weight and high % DDA, is desirable for antifungal applications against human pathogens. Moreover, chitosans as well as their nanoparticles were found to be hemocompatible and are therefore safe for healthcare applications.

Molecular studies of NAD- and NADP-glutamate dehydrogenases decipher the conundrum of yeast-hypha dimorphism in zygomycete Benjaminiella poitrasii.

Benjaminiella poitrasii, a zygomycete, shows glucose- and temperature-dependent yeast (Y)-hypha (H) dimorphic transition. Earlier, we reported the biochemical correlation of relative proportion of NAD- and NADP-glutamate dehydrogenases (GDHs) with Y-H transition. Further, we observed the presence of one NAD-GDH and two form-specific NADP-GDH isoenzymes in B. poitrasii. However, molecular studies are necessary to elucidate the explicit role of GDHs in regulating Y-H reversible transition. Here, we report the isolation and characterization of one NAD (BpNADGDH, 2.643 kb) and two separate genes, BpNADPGDH I (Y-form specific, 1.365 kb) and BpNADPGDH II (H-form specific, 1.368 kb) coding for NADP-GDH isoenzymes in B. poitrasii. The transcriptional profiling during Y-H transition showed higher BpNADPGDH I expression in Y cells while expression of BpNADPGDH II was higher in H cells. Moreover, the yeast-form monomorphic mutant (Y-5) did not show BpNADPGDH II expression under normal dimorphism triggering conditions. Transformation with H-form specific BpNADPGDH II induced the germ tube formation in Y-5, which confirmed the cause-effect relationship between BpNADPGDH genes and morphological outcome in B. poitrasii. Interestingly, expression of H-form specific BpNADPGDH II also induced germ tube formation in human pathogenic, non-dimorphic yeast Candida glabrata, which further corroborated our findings.

The puzzle of highly virulent Metarhizium anisopliae strains from Annona squamosa fields against Helicoverpa armigera.

In our search for indigenous virulent strains of the entomopathogenic fungi, we observed that Metarhizium isolates from soils associated with Annona squamosa (custard apple) have higher virulence (>90% mortality of Helicoverpa armigera larvae at 1/10th spore concentration) than strains isolated from Solanum lycopersicum (tomato) fields. Proteomic analysis revealed two insecticidal cyclopeptides of A. squamosa origin in the M. anisopliae strains that led to higher virulence against H. armigera. Transcriptomic and genomic data indicated that M. anisopliae strains and A. squamosa had more than 20 genes in common, including those for cyclic hexapeptide synthase, non-ribosomal peptide synthetase, and plant cyclotide genes, which are involved in the biosynthesis of insecticidal cyclopeptides. These genes were absent in M. anisopliae strains isolated from the S. lycopersicum fields. Further, these strains can establish an endophytic relationship with A. squamosa suggesting that these rhizospheric strains originally could be endophytes, which were eventually released into the soil. Further, Metarhizium strains associated with Capsicum annuum (chili), Azadirachta indica (neem), and Carica papaya (papaya) - plants with insecticidal properties - also had higher virulence against H. armigera. Thus exploration of rhizospheres of plants producing insecticidal metabolites to isolate entomopathogenic fungi, per se, could be a viable strategy in agricultural for crop protection.

Catheter Assisted Management of Massive Pulmonary Embolism.

Pulmonary thromboembolism is common and missed by clinicians. We report a case of massive pulmonary embolism which was life threatening treated by the catheter assisted technique. Anticoagulation is the mainstay of therapy for most patients, with thrombolytic therapy reserved for some patients.1 Recent studies have suggested a role for systemic or catheter-directed thrombolytic therapy in selected patients.2 We present a case of a patient who presented with an PE, was successfully treated with catheter-directed thrombolysis.

Asymptomatic Presentation of Large Cardiac Ball.

A 45 years female presented with short duration of dry cough and atypical chest pain. Chest X ray showed cardiomegaly with a bulge at the right heart border and curvilinear calcification in left upper abdomen. Transthoracic echocardiography (TTE) revealed a cystic lesion in the right ventricle free wall causing compression of right atrial and ventricular cavity. Cardiac CT confirmed this cyst as hydatid cyst. Patient underwent successful excision of right ventricular hydatid cyst.

Mechanism of action of novel synthetic dodecapeptides against Candida albicans.

BACKGROUND: Three de novo designed low molecular weight cationic peptides (IJ2, IJ3 and IJ4) containing an unnatural amino acid α,ß-didehydrophenylalanine (∆Phe) exhibited potent antifungal activity against fluconazole (FLC) sensitive and resistant clinical isolates of Candida albicans as well as non-albicans and other yeast and filamentous pathogenic fungi. In the present study, their synthesis, susceptibility of different fungi and the mechanism of anti-candidal action have been elucidated. METHODS: The antimicrobial peptides (AMPs) were synthesized by solid-phase method and checked for antifungal activity against different yeasts and fungi by broth microdilution method. Anti-candidal mode of action of the peptides was investigated through detecting membrane permeabilization by confocal microscopy, Reactive Oxygen Species (ROS) generation by fluorometry, apoptosis and necrosis by flow cytometry and cell wall damage using Scanning and Transmission Electron Microscopy. RESULTS AND CONCLUSIONS: The MIC of the peptides against C. albicans and other yeast and filamentous fungal pathogens ranged between 3.91 and 250µM. All three peptides exhibited effect on multiple targets in C. albicans including disruption of cell wall structures, compromised cell membrane permeability leading to their enhanced entry into the cells, accumulation of ROS and induction of apoptosis. The peptides also showed synergistic effect when used in combination with fluconazole (FLC) and caspofungin (CAS) against C. albicans. GENERAL SIGNIFICANCE: The study suggests that the AMPs alone or in combination with conventional antifungals hold promise for the control of fungal pathogens, and need to be further explored for treatment of fungal infections.

Healthcare-associated fungal infections and emerging pathogens during the COVID-19 pandemic.

Historically, fungi were mainly identified as plant and insect pathogens since they grow at 28°C. At the same time, bacteria are known to be the most common human pathogens as they are compatible with the host body temperature of 37°C. Because of immunocompromised hosts, cancer therapy, and malnutrition, fungi are rapidly gaining attention as human pathogens. Over 150 million people have severe fungal infections, which lead to approximately more than one million deaths per year. Moreover, diseases like cancer involving long-term therapy and prophylactic use of antifungal drugs in high-risk patients have increased the emergence of drug-resistant fungi, including highly virulent strains such as Candida auris. This clinical spectrum of fungal diseases ranges from superficial mucocutaneous lesions to more severe and life-threatening infections. This review article summarizes the effect of hospital environments, especially during the COVID-19 pandemic, on fungal infections and emerging pathogens. The review also provides insights into the various antifungal drugs and their existing challenges, thereby driving the need to search for novel antifungal agents.

Rhizospheric Bacillus spp. Exhibit Miticidal Efficacy against Oligonychus coffeae (Acari: Tetranychidae) of Tea.

Oligonychus coffeae (Acari: Tetranychidae), popularly known as red spider mite (RSM) is one of the major pests of commercial tea (Camellia sinensis (L.) O. Kuntze) plantation world over. Many attempts have been made in the past to control this devastating pest using a variety of microbial bioagents, however, area-wise field success is very limited. We carried out an in vitro study to explore the potential of rhizospheric Bacillus spp. (B. amyloliquefaciens BAC1, B. subtilis LB22, and B. velezensis AB22) against O. coffeae through adulticidal and ovicidal activity. The 100% adult and egg mortality was observed with bacterial suspension (1 × 109 CFU/mL) by B. velezensis AB22, showing the lowest LC50 values for both adults and eggs of O. coffeae, i.e., 0.28 × 105 and 0.29 × 105, respectively. The study also throws some insights into the underlying mechanism through electron microscopy study and identification of some putative pesticidal metabolites from all the species. The three Bacillus species were observed to have four commonly secreted putative bioactive secondary metabolites, brevianamide A, heptadecanoic acid, thiolutin, and versimide responsible for their bio-efficacy against O. coffeae. The outcome of our study provides a strong possibility of introducing Bacillus spp. as a biological miticide and developing synthetic metabolites mimicking the mechanistic pathway involved in microbial bioefficacy.

New 1,2,3-Triazole-Appended Bis-pyrazoles: Synthesis, Bioevaluation, and Molecular Docking.

The present work describes design of a small library of new 1,2,3-triazole-appended bis-pyrazoles by using a molecular hybridization approach, and the synthesized hybrids were evaluated for their antifungal activity against different fungal strains, namely, Candida albicans, Cryptococcus neoformans, Candida glabrata, Candida tropicalis, Aspergillus niger, and Aspergillus fumigatus. All the compounds exhibited broad-spectrum activity against the tested fungal strains with excellent minimum inhibitory concentration values. The molecular docking study against sterol 14α-demethylase (CYP51) could provide valuable insights into the binding modes and affinity of these compounds. Furthermore, these compounds were also evaluated for their antioxidant activity, which also resulted in promising data.

NADP-dependent glutamate dehydrogenases in a dimorphic zygomycete Benjaminiella poitrasii: Purification, characterization and their evaluation as an antifungal drug target.

BACKGROUND: It has been reported that the genes coding for NADP-dependent glutamate dehydrogenases (NADP-GDHs) showed a cause-effect relationship with Yeast-Hypha (YH) reversible transition in a zygomycete Benjaminiella poitrasii. As YH transition is significant in human pathogenic fungi for their survival and proliferation in the host, the NADP-GDHs can be explored as antifungal drug targets. METHODS: The yeast-form specific BpNADPGDH I and hyphal-form specific BpNADPGDH II of B. poitrasii were purified by heterologous expression in E. coli BL-21 cells and characterized. The structural analogs of L-glutamate, dimethyl esters of isophthalic acid (DMIP) and its derivatives were designed, synthesized and screened for inhibition of NADP-GDH activity as well as YH transition in B. poitrasii, and also in human pathogenic Candida albicans strains. RESULTS: The BpNADPGDH I and BpNADPGDH II were found to be homo-hexameric proteins with native molecular mass of 282 kDa and 298 kDa, respectively and subunit molecular weights of 47 kDa and 49 kDa, respectively. Besides the distinct kinetic properties, BpNADPGDH I and BpNADPGDH II were found to be regulated by cAMP-dependent- and Calmodulin (CaM) dependent- protein kinases, respectively. The DMIP compounds showed a more pronounced effect on H-form specific BpNADPGDH II and inhibited YH transition as well as growth in B. poitrasii and C. albicans strains. CONCLUSION: The present study will be useful to design and develop antifungal drugs against dimorphic human pathogens using glutamate dehydrogenase as a target. SIGNIFICANCE: Glutamate dehydrogenases can be explored as a target against human pathogenic fungi.

Exploration of click reaction for the synthesis of modified nucleosides as chitin synthase inhibitors.

Click reaction approach toward the synthesis of two sets of novel 1,2,3-triazolyl linked uridine derivatives 19a-19g and 21a-21g was achieved by Cu(I)-catalyzed 1,3-dipolar cycloaddition of 5'-azido-5'-deoxy-2',3'-O-(1-methylethylidene)uridine (17) with propargylated ether of phenols 18a-18g and propargylated esters 20a-20g. Structure of one of the representative compound 19d was unambiguously confirmed by X-ray crystallography. Chitin synthase inhibition study of all these compounds 19a-19g and 21a-21g was carried out to develop antifungal strategy. Compounds 19d, 19e, 19f, and 21f were identified as potent chitin synthase inhibitors by comparing with nikkomycin. Compounds 19a, 19b, 19c, 19d, 21a, and 21b showed good antifungal activity against human and plant pathogens. Compounds 19a, 19b, 19f, 21c, 21f, and 21g were identified as lead chitin synthase inhibitors for further modifications by comparing results of inhibition of growth, % germ tube formation and chitin synthase activity.

Natural yeast flora of different varieties of grapes used for wine making in India.

The natural Saccharomyces and non-Saccharomyces yeast flora present on the grape berries significantly affect wine production. Six grape varieties, Bangalore blue, Zinfandel, Cabernet, Chenin Blanc, Sauvignon Blanc and Shiraz are being used in India for wine making. The yeast diversity was studied on the basis of morphological, colony, physiological characteristics and 5.8S-ITS sequencing of rDNA of the isolates. Eleven different species belonging to seven genera were identified as: Candida azyma, Candida quercitrusa, Debaryomyces hansenii, Hanseniaspora guilliermondii, Hanseniaspora viniae, Hanseniaspora uvarum, Issatchenkia orientalis, Issatchenkia terricola, Pichia membranifaciens, Saccharomyces cerevisiae and Zygoascus steatolyticus. H. guilliermondii was the predominant species while S. cerevisiae was observed occasionally in the six vine varieties. For the first time, C. azyma was isolated from Bangalore blue and Cabernet varieties grown in different localities. This association may be attributed to the change in cropping pattern from sugarcane to viticulture in the vine growing regions and the known association of C. azyma with sugarcane phylloplane. Further analysis of the indigenous strains and the qualitative and quantitative changes in the flora during fermentation will be useful to understand wine quality and to design preservation strategies to control wine spoilage.

Clinical and angiographic profile of very young adults presenting with first acute myocardial infarction: Data from a tertiary care center in Central India.

Acute myocardial infarction (AMI) is afflicting young individuals more frequently nowadays. The present study was planned to evaluate the clinical and angiographic profile in adults aged less than 30 years, presenting with first AMI as data from Central India is very scarce. This cross-sectional study included 41 patients of STEMI with a mean age of 27 ± 2.8 years. Risk factors were male gender (95.1%), dyslipidemia (51.2%), tobacco consumption (48.8%), obesity (34.1%), and smoking (29.3%). Anterior wall myocardial infarction (AWMI) was the most common presentation (82.9%) with obstructive CAD noted in 61% cases frequently due to LAD coronary artery involvement (46.4%).

Retrospective Study of Clinical and Epidemiological Parameters of Patients Undergoing Percutaneous Coronary Intervention with Their Follow-Up.

AIM: To study clinical and epidemiological parameters of patients undergoing percutaneous coronary intervention (PCI) and to follow them up for understanding the outcomes of the procedure. MATERIAL AND METHODS: This is a retrospective data analysis of 862 patients who underwent PCI from January 2016 to November 2017. RESULTS: Out of 862 patients, 611 (70.88%) were male & 251 (29.12%) were female, with the mean age being 55. 243 (28.19%) were diabetic, 470 (54.52%) were hypertensive, 158 (18.32%) patients were tobacco chewer, 215 (24.92%) were smokers and 111 (12.87%) were alcoholic. 636 (73.78%) patients had STEMI, 153 (17.74%) had NSTE-ACS, 61 (7.07%) had CSA.578 (67.05%) were SVD, 262 (30.39%) were DVD and 19 (2.20%) were TVD. Out of SVD, 350 (60.55%) patients had LAD involvement and among DVD patients, LAD and RCA were most commonly involved in 107 (40.83%) patients. On follow-up of mean 604.42 days (minimum 236 days, maximum 909 days), 2 (0.23%) episodes of subacute stent thrombosis occurred and 11 (1.27%) patients had ISR but no mortality was reported. CONCLUSION: The study shows affection of young population predominately and genders inequality, suggesting primarily male disease. PCI is often sought in ACS and CSA is predominately treated medically. Thrombolysis remains the first treatment received by STEMI patients. SVD is the most common angiographic diagnosis with LAD predominately affected vessel. This real world-data on clopidogrel with aspirin as dual antiplatelet therapy and second-generation stent shows negligible event of stent thrombosis and ISR. LIMITATION: Due to non-invasive follow-up, the exact amount of stent restenosis cannot be calculated. IMPACT ON DAILY PRACTICE: This real world-data on clopidogrel with aspirin as dual antiplatelet therapy and second-generation stent shows negligible event of stent thrombosis and ISR. This can help reduce the cost burden on society and help better distribution of health budget.

Synthesis and antimicrobial activity of beta-lactam-bile acid conjugates linked via triazole.

Synthesis of novel 1,2,3-triazole-linked beta-lactam-bile acid conjugates 17-24 using 1,3-dipolar cycloaddition reaction of azido beta-lactam and terminal alkyne of bile acids in the presence of Cu(I) catalyst (click chemistry) have been realized. These molecules were evaluated in vitro for their antifungal and antibacterial activities. Most of the compounds exhibited significant antifungal and moderate antibacterial activity against all the tested strains.

Synthesis of chimeric tetrapeptide-linked cholic acid derivatives: impending synergistic agents.

Tetrapeptides derived from glycine and beta-alanine were hooked at the C-3beta position of the modified cholic acid to realize novel linear tetrapeptide-linked cholic acid derivatives. All the synthesized compounds were tested against a wide variety of microorganisms (gram-negative bacteria, gram-positive bacteria and fungi) and their cytotoxicity was evaluated against human embryonic kidney (HEK293) and human mammary adenocarcinoma (MCF-7) cell lines. While relatively inactive by themselves, these compounds interact synergistically with antibiotics such as fluconazole and erythromycin to inhibit growth of fungi and bacteria, respectively, at 1-24 microg/mL. The synergistic effect shown by our novel compounds is due to their inherent amphiphilicity. The fractional inhibitory concentrations reported are comparable to those reported for Polymyxin B derivatives.

Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-beta-lactam.

We report herein the synthesis and biological evaluation of bile acid dimers linked through 1,2,3-triazole and bis-beta-lactam. The dimers were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-beta-lactams , and terminal alkynes derived from cholic acid/deoxycholic acid in the presence of Cu(i) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7 cells were also established.

Facile and Solvent-free Domino Synthesis of New Quinolidinyl-2,4- thiazolidinones: Antifungal Activity and Molecular Docking.

OBJECTIVE: We have synthesized new quinolidinyl-thiazolidinones via Knoevenagel condensation- alkylation reaction, catalyzed by [Et3NH][HSO4]. The present approach offers several advantages such as higher yields, eco-friendly reaction condition and economic availability of the catalyst. METHOD: The newly synthesized compounds were evaluated for their in vitro antifungal activity against six fungal strains. Some of the synthesized conjugates displayed good to moderate antifungal activity. CONCLUSION: Again, the molecular docking study performed against the fungal sterol 14α-demethylase (CYP51) showed an excellent binding affinity towards the enzyme which could rationalize the promising antifungal activity portrayed by these derivatives and provides a platform for structure based drug design.

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance.

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and screening for the selection of a fast-acting, highly virulent entomopathogenic fungus are important steps. Entomopathogenic fungi, such as Metarhizium, Beauveria, and Nomurea, which act by contact, are better suited than Bacillus thuringiensis or nucleopolyhedrosis virus (NPV), which must be ingested by the insect pest. In the present work, we isolated 68 Metarhizium strains from infected insects using a soil dilution and bait method. The isolates were identified by the amplification and sequencing of the ITS1-5.8S-ITS2 and 26S rDNA region. The most virulent strain of Metarhizium anisopliae was selected based on the median lethal concentration (LC50) and time (LT50) obtained in insect bioassays against III-instar larvae of Helicoverpa armigera. The mass production of spores by the selected strain was carried out with solid-state fermentation (SSF) using rice as a substrate for 14 days. Spores were extracted from the sporulated biomass using 0.1% tween-80, and different formulations of the spores were prepared. Field trials of the formulations for the control of an H. armigera infestation in pigeon peas were carried out by randomized block design. The infestation control levels obtained with oil and aqueous formulations (78.0% and 70.9%, respectively) were better than the 63.4% obtained with chemical pesticide.

Selection of reference genes for quantitative real-time RT-PCR assays in different morphological forms of dimorphic zygomycetous fungus Benjaminiella poitrasii.

Benjaminiella poitrasii, a dimorphic non-pathogenic zygomycetous fungus, exhibits a morphological yeast (Y) to hypha (H) reversible transition in the vegetative phase, sporangiospores (S) in the asexual phase and zygospores (Z) in the sexual phase. To study the gene expression across these diverse morphological forms, suitable reference genes are required. In the present study, 13 genes viz. ACT, 18S rRNA, eEF1α, eEF-Tu,eIF-1A, Tub-α, Tub-b, Ubc, GAPDH, Try, WS-21, NADGDH and NADPGDH were evaluated for their potential as a reference, particularly for studying gene expression during the Y-H reversible transition and also for other asexual and sexual life stages of B. poitrasii. Analysis of RT-qPCR data using geNorm, normFinder and BestKeeper software revealed that genes such as Ubc, 18S rRNA and WS-21 were expressed at constant levels in each given subset of RNA samples from all the morphological phases of B. poitrasii. Therefore, these reference genes can be used to elucidate the role of morpho-genes in B. poitrasii. Further, use of the two most stably expressed genes (Ubc and WS-21) to normalize the expression of the ornithine decarboxylase gene (Bpodc) in different morphological forms of B. poitrasii, generated more reliable results, indicating that our selection of reference genes was appropriate.