Dibenzothiophene desulfurization in hydrocarbon environment by Staphylococcus sp. resting cells

Staphylococcus sp. strain S3/C desulfurized dibenzothiophene/n-hexadecane (3 mg ml^–1) in a hydrocarbon aqueous biphasic culture. The resting cells decreased the sulfur content of the hydrocarbon phase by 57% at 2.2 mg l^–1 h^–1 in the absence of any additional carbon and sulfur source.     

Cytological studies on triploid Trigonella corniculata L.

Two spontaneous triploid plants of Trigonella corniculata (3n=24) were observed in a population raised from irradiated seeds. Up to seven trivalents per cell were observed. One of the plants appeared to be a double translocation heterozygote involving two non-homologous chromosomes, and therefore could form a quadrivalent, a ring trivalent and bivalents without corresponding univalents.     

Paradoxical Enhancement of the Activity of a Bacterial Multidrug Transporter Caused by Substitutions of a Conserved Residue

Substitution of threonine or serine for the evolutionary conserved intramembrane proline P³⁴⁷ of the Bacillus subtilis multidrug transporter Bmr significantly increases the toxin-effluxing activity of Bmr without affecting its abundance in the cell. In cocultivation experiments, we demonstrate that although the mutant T³⁴⁷ Bmr is advantageous to cells growing in the presence of a toxin, the wild-type P³⁴⁷ Bmr is advantageous under the conditions of nutritional limitation. This may explain why Bmr has evolved the way it did, that is, with proline at position 347. These observations provide a basis for speculating that the evolution of Bmr has been determined by its presently unidentified natural function rather than by its ability to expel diverse toxins from the cell.     

Exploiting the antivirulence efficacy of an ajoene-ciprofloxacin combination against Pseudomonas aeruginosa biofilm associated murine acute pyelonephritis

The study investigated the in vitro, ex vivo and in vivo efficacy of ajoene and ciprofloxacin (CIP) alone and in combination against Pseudomonas aeruginosa biofilms and biofilm-associated murine acute pyelonephritis. The ajoene–CIP combination exhibited significant greater (p < 0.05) antimotility and biofilm inhibitory effects than those obtained when they were applied individually. The combined action of the agents resulted in a significant increase in serum sensitivity and phagocytic uptake and killing of P. aeruginosa (p < 0.001) compared to the untreated control. Mice groups treated with an ajoene (25 mg kg^?1) and CIP (30 mg kg^?1 or 15 mg kg^?1) combination showed a significantly (p < 0.001) reduced bacterial load in the kidney and bladder as compared to that of infected controls and mice treated with solo agents on the fifth day post-infection. The decreased levels of biomarkers and photomicrographs of the kidney tissue of the treated mice showed a reduced severity of damage. Hence, the study highlights the antivirulent and therapeutic efficacy of the ajoene-CIP combination at the minimal dosage of CIP.     

A membrane fusion protein,Ykt6, regulates epithelial cell migration via microRNA-mediated suppression of Junctional Adhesion Molecule A

Vesicle trafficking regulates epithelial cell migration by remodeling matrix adhesions and delivering signaling molecules to the migrating leading edge. Membrane fusion, which is driven by soluble N-ethylmaleimide-sensitive factor associated receptor (SNARE) proteins, is an essential step of vesicle trafficking. Mammalian SNAREs represent a large group of proteins, but few have been implicated in the regulation of cell migration. Ykt6 is a unique SNARE existing in equilibrium between active membrane-bound and inactive cytoplasmic pools, and mediating vesicle trafficking between different intracellular compartments. The biological functions of this protein remain poorly understood. In the present study, we found that Ykt6 acts as a negative regulator of migration and invasion of human prostate epithelial cells. Furthermore, Ykt6 regulates the integrity of epithelial adherens and tight junctions. The observed anti-migratory activity of Ykt6 is mediated by a unique mechanism involving the expressional upregulation of microRNA 145, which selectively decreases the cellular level of Junctional Adhesion Molecule (JAM) A. This decreased JAM-A expression limits the activity of Rap1 and Rac1 small GTPases, thereby attenuating cell spreading and motility. The described novel functions of Ykt6 could be essential for the regulation of epithelial barriers, epithelial repair, and metastatic dissemination of cancer cells.     

Small Intestine Microbiota Regulate Host Digestive and Absorptive Adaptive Responses to Dietary Lipids

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Glucose deprivation induced upregulation of phosphoenolpyruvate carboxykinase modulates virulence in Leishmania donovani

Various physiological stimuli trigger the conversion of noninfective Leishmania donovani promastigotes to the infective form. Here, we present the first evidence of the effect of glucose starvation, on virulence and survival of these parasites. Glucose starvation resulted in a decrease in metabolically active parasites and their proliferation. However, this was reversed by supplementation of gluconeogenic amino acids. Glucose starvation induced metacyclogenesis and enhanced virulence through protein kinase A regulatory subunit (LdPKAR1) mediated autophagy. Glucose starvation driven oxidative stress upregulated the antioxidant machinery, culminating in increased infectivity and greater parasitic load in primary macrophages. Interestingly, phosphoenolpyruvate carboxykinase (LdPEPCK), a gluconeogenic enzyme, exhibited the highest activity under glucose starvation to regulate growth of L. donovani by alternatively utilising amino acids. Deletion of LdPEPCK (Δpepck) decreased virulent traits and parasitic load in primary macrophages but increased autophagosome formation in the mutant parasites. Furthermore, Δpepck parasites failed to activate the Pentose Phosphate Pathway shunt, abrogating NADPH/NADP⁺ homoeostasis, conferring increased susceptibility towards oxidants following glucose starvation. In conclusion, this study showed that L. donovani undertakes metabolic rearrangements via gluconeogenesis under glucose starvation for acquiring virulence and its survival in the hostile environment.