Subcutaneous Mycotic Cyst Caused by <Emphasis Type="Italic">Roussoella percutanea</Emphasis> in a UK Renal Transplant Patient

Fungi from more than 100 genera have been implicated in subcutaneous fungal infections, usually following traumatic inoculation of the etiologic agent. With the advent of molecular approaches to fungal identification and taxonomy, novel agents of subcutaneous mycoses are increasingly reported. In this manner, Roussoella percutanea, a novel species in Pleosporales, was described in 2014 from a subcutaneous mass in an immunocompetent male adult. Two additional cases involving renal transplant recipients were recently reported from patients resident in France and Germany, with several further cases discovered after analyses of historical culture collection isolates. Here, we describe a new case of subcutaneous R. percutanea infection, causing a mycotic cyst in a renal transplant patient resident in the UK. Although fungal infection was confirmed histologically, viable fungal isolates could not be recovered in culture from biopsy material and identification of the causative agent relied upon PCR amplification and sequencing of fungal rDNA genes. This is the fourth well-documented case of infection with R. percutanea in renal transplant patients, and the first reported from a patient resident in the UK. The current case illustrates the importance of molecular approaches for the identification of emerging fungal pathogens in culture-negative subcutaneous fungal infections.     

Febrifugine analogues as Leishmania donovani trypanothione reductase inhibitors: binding energy analysis assisted by molecular docking,ADMET and molecular dynamics simulation

Visceral leishmaniasis affects people from 70 countries worldwide, mostly from Indian, African and south American continent. The increasing resistance to antimonial, miltefosine and frequent toxicity of amphotericin B drives an urgent need to develop an antileishmanial drug with excellent efficacy and safety profile. In this study we have docked series of febrifugine analogues (n = 8813) against trypanothione reductase in three sequential docking modes. Extra precision docking resulted into 108 ligands showing better docking score as compared to two reference ligand. Furthermore, 108 febrifugine analogues and reference inhibitor clomipramine were subjected to ADMET, QikProp and molecular mechanics, the generalized born model and solvent accessibility study to ensure the toxicity caused by compounds and binding-free energy, respectively. Two best ligands (FFG7 and FFG2) qualifying above screening parameters were further subjected to molecular dynamics simulation. Conducting these studies, here we confirmed that 6-chloro-3-[3-(3-hydroxy-2-piperidyl)-2-oxo-propyl]-7-(4-pyridyl) quinazolin-4-one can be potential drug candidate to fight against Leishmania donovani parasites.     

Qualitative characterization of the rat liver mitochondrial lipidome using LC–MS profiling and high energy collisional dissociation (HCD) all ion fragmentation

Lipids play multiple roles essential for proper mitochondrial function, from their involvement in membrane structure and fluidity, cellular energy storage, and signaling. Lipids are also major targets for reactive species, and their peroxidation byproducts themselves mediate further damage. Thousands of lipid species, from multiple classes and categories, are involved in these processes, suggesting lipid quantitative and structural analysis can help provide a better understanding of mitochondrial physiological status. Due to the diversity of lipids that contribute to and reflect mitochondrial function, analytical methods should ideally cover a wide range of lipid classes, and yield both quantitative and structural information. We developed a high resolution LC–MS method that is able to monitor the major lipid classes found in biospecimens (i.e. biofluids, cells and tissues) with relative quantitation in an efficient, sensitive, and robust manner while also characterizing individual lipid side-chains, by all ion high energy collisional dissociation fragmentation and chromatographic alignment. This method was used to profile the liver mitochondrial lipids from 192 rats undergoing a dietary macronutrient study in which changes in mitochondria function are related to changes in the major fat and glycemic index component of each diet. A total of 381 unique lipids, spanning 5 of the major LIPID MAPS defined categories, including fatty acyls, glycerophospholipids, glycerolipids, sphingolipids and prenols, were identified in mitochondria using the non-targeted LC–MS analysis in both positive and negative mode. The intention of this report is to show the breadth of this non-targeted LC–MS profiling method with regards to its ability to profile, identify and characterize the mitochondrial lipidome and the details of this will be discussed.     

Alternaria tenuis Auct. in Bombay-Maharashtra

Summary This paper gives an account of distribution, host range and economic importance of the speciesAlternaria tenuis Auct, as it occurs in Bombay-Maharashtra (India). The species has been collected on 51 hosts distributed among 23 host families of which 5 are new host records not previously reported in literature.Part of the author's Ph. D. (Agri.) thesis approved by the University of Poona, Poona (India), 1964.Junior Research Fellow of the University Grants Commission, New Delhi, (India) in Mycology and Plant Pathology.     

Effect of prostaglandins on the steroidogenesis in human ovarian tissues

Although prostaglandins are luteolytic in some species, in conditions they stimulate progesterone production in the corpus luteum (1). Apart from this effect prostaglandins may also stimulate other steps in the steroidogenic sequence e.g. corticosteroidogenesis in superfused rat adrenal glands (2) and aromatization of testosterone by perfused human placenta (3). With this possibility in view and also because of paucity of data on the effect of prostaglandins on steroidogenesis in human ovarian tissues we have been studying under conditions the effect of prostaglandins on progesterone formation in human corpora lutea and on the utilization of C₂₁ steroids by the luteal and follicular compartments of the ovary. These studies are still in progress. However, the data obtained so far indicates that in addition to stimulating progesterone synthesis in the corpus luteum prostaglandins may also affect other steps in steroidogenesis in human ovarian tissues. We wish to report here in brief these preliminary results.     

A redox-active crosslinker reveals an essential and inhibitable oxidative folding network in the endoplasmic reticulum of malaria parasites

Malaria remains a major global health problem, creating a constant need for research to identify druggable weaknesses in P. falciparum biology. As important components of cellular redox biology, members of the Thioredoxin (Trx) superfamily of proteins have received interest as potential drug targets in Apicomplexans. However, the function and essentiality of endoplasmic reticulum (ER)-localized Trx-domain proteins within P. falciparum has not been investigated. We generated conditional mutants of the protein PfJ2—an ER chaperone and member of the Trx superfamily—and show that it is essential for asexual parasite survival. Using a crosslinker specific for redox-active cysteines, we identified PfJ2 substrates as PfPDI8 and PfPDI11, both members of the Trx superfamily as well, which suggests a redox-regulatory role for PfJ2. Knockdown of these PDIs in PfJ2 conditional mutants show that PfPDI11 may not be essential. However, PfPDI8 is required for asexual growth and our data suggest it may work in a complex with PfJ2 and other ER chaperones. Finally, we show that the redox interactions between these Trx-domain proteins in the parasite ER and their substrates are sensitive to small molecule inhibition. Together these data build a model for how Trx-domain proteins in the P. falciparum ER work together to assist protein folding and demonstrate the suitability of ER-localized Trx-domain proteins for antimalarial drug development.     

Investigating the pharmacodynamic durability of GalNAc–siRNA conjugates

One hallmark of trivalent N-acetylgalactosamine (GalNAc)-conjugated siRNAs is the remarkable durability of silencing that can persist for months in preclinical species and humans. Here, we investigated the underlying biology supporting this extended duration of pharmacological activity. We found that siRNA accumulation and stability in acidic intracellular compartments is critical for long-term activity. We show that functional siRNA can be liberated from these compartments and loaded into newly generated Argonaute 2 protein complexes weeks after dosing, enabling continuous RNAi activity over time. Identical siRNAs delivered in lipid nanoparticles or as GalNAc conjugates were dose-adjusted to achieve similar knockdown, but only GalNAc–siRNAs supported an extended duration of activity, illustrating the importance of receptor-mediated siRNA trafficking in the process. Taken together, we provide several lines of evidence that acidic intracellular compartments serve as a long-term depot for GalNAc–siRNA conjugates and are the major contributor to the extended duration of activity observed in vivo.