Rapid identification of biosurfactant-producing bacterial strains using a cell surface hydrophobicity technique

Rapid identification of biosurfactant-producing bacterial strains was achieved by assaying cell surface hydrophobicity which had a direct correlation with biosurfactant production by Serratia marcescens, Pseudomonas aeruginosa, Bacillus pumilus, B. laterosporus, Acineto- bacter calcoaceticus, Escherichia coli and Staphylococcus aureus. These properties namely, Hydrophobic Interaction Chromatography, Salt Aggregation Test, Bacterial Adherence To Hydrocarbon and adhesion to polystyrene by Replica Plate test, provide a simple means for identifying bacteria associated with the production of biosurfactants.     

Pulmonary Artery Pseudoaneurysm in COVID-19-Associated Pulmonary Mucormycosis: Case Series and Systematic Review of the Literature

Mycopathologia - Literature on COVID-19-associated pulmonary mucormycosis (CAPM) is sparse. Pulmonary artery pseudoaneurysm (PAP) is an uncommon complication of pulmonary mucormycosis (PM), and...     

Biofilm formation by <Emphasis Type="Italic">Candida albicans</Emphasis> isolated from intrauterine devices

Our survey revealed that infected intrauterine devices (IUDs) recovered from patients suffering from reproductive tract infections (RTIs) were tainted with Candida biofilm composed of a single or multiple species. Scanning electron microscopy (SEM) analysis of C. albicans biofilm topography showed that it consists of a dense network of mono- or multilayer of cells embedded within the matrix of extracellular polymeric substances (EPS). Confocal scanning laser microscopy (CSLM) and atomic force microscopy (AFM) images depicted that C. albicans biofilms have a highly heterogeneous architecture composed of cellular and noncellular elements with EPS distributed in the cell-surface periphery or at cell-cell interface. Biochemical analysis showed that EPS produced by C. albicans biofilm contained significantly reduced total carbohydrate (40%), protein (5%) and enhanced amount of hexosamine (4%) in contrast to its planktonic counterparts. The in vitro activity of antifungal agents amphotericin B, nystatin, fluconazole and chlorhexidine against pre-formed C. albicans biofilm, assessed using XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay revealed increased resistance of these infectious biofilm (50% reduction in metabolic activity at a concentration of 8, 16, 64, 128 μg/ml respectively) in comparison to its planktonic form.     

Oily sludge degradation by bacteria from Ankleshwar, India

Three bacterial strains, Bacillus sp. SV9, Acinetobacter sp. SV4 and Pseudomonas sp., SV17 from contaminated soil in Ankleshwar, India were tested for their ability to degrade the complex mixture of petroleum hydrocarbons (such as alkanes, aromatics, resins and asphaltenes), sediments, heavy metals and water known as oily sludge. Gravimetric analysis showed that Bacillus sp. SV9 degraded approx. 59% of the oily sludge in 5 days at 30 °C whereas Acinetobacter sp. SV4 and Pseudomonas sp. SV17 degraded 37% and 35%. Capillary gas chromatographic analysis revealed that after 5 days the Bacillus strain was able to degrade oily sludge components of chain length C₁₂–C₃₀ and aromatics more effectively than the other two strains. Maximum drop in surface tension (from 70 to 28.4 mN/m) was accompanied by maximum biosurfactant production (6.7 g l⁻¹) in Bacillus sp. SV9 after 72 h, these results collectively indicating that this bacterial strain has considerable potential for bioremediation of oily sludge.     

Motor protein Myo1c is a podocyte protein that facilitates the transport of slit diaphragm protein Neph1 to the podocyte membrane

The podocyte proteins Neph1 and nephrin organize a signaling complex at the podocyte cell membrane that forms the structural framework for a functional glomerular filtration barrier. Mechanisms regulating the movement of these proteins to and from the membrane are currently unknown. This study identifies a novel interaction between Neph1 and the motor protein Myo1c, where Myo1c plays an active role in targeting Neph1 to the podocyte cell membrane. Using in vivo and in vitro experiments, we provide data supporting a direct interaction between Neph1 and Myo1c which is dynamic and actin dependent. Unlike wild-type Myo1c, the membrane localization of Neph1 was significantly reduced in podocytes expressing dominant negative Myo1c. In addition, Neph1 failed to localize at the podocyte cell membrane and cell junctions in Myo1c-depleted podocytes. We further demonstrate that similarly to Neph1, Myo1c also binds nephrin and reduces its localization at the podocyte cell membrane. A functional analysis of Myo1c knockdown cells showed defects in cell migration, as determined by a wound assay. In addition, the ability to form tight junctions was impaired in Myo1c knockdown cells, as determined by transepithelial electric resistance (TER) and bovine serum albumin (BSA) permeability assays. These results identify a novel Myo1c-dependent molecular mechanism that mediates the dynamic organization of Neph1 and nephrin at the slit diaphragm and is critical for podocyte function.     

Impact of oxidative and osmotic stresses on Candida albicans biofilm formation

Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H₂O₂) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches.     

Steroid metabolism by monkey and human spermatozoa

Freshly ejaculated spermatozoa from monkey and human were washed and incubated with tritium labelled androgens or estradiol to study the pattern of spermatozoa steroid metabolism. When equal concentrations of steroid substrates were used for incubation, monkey and human spermatozoa showed very similar pattern of steroid conversion. Spermatozoa from both species converted testosterone mainly to androstenedione, but reverse conversion of androstenedione to testosterone was negligible. Estradiol-17 beta was converted mainly to estrone. The close similarity between the spermatozoa of monkey and men in their steroid metabolic pattern indicates that the rhesus monkey could be an useful animal model to study the effect of drugs on the metabolic pattern of human spermatozoa.     

Circadian and circannual changes in the testicular function of adult rhesus monkeys

The endocrine and gametogenic status of the testes were studied in 9 healthy adult rhesus monkeys of proven fertility throughout a one-year period. Testosterone levels were estimated by radioimmunoassay in blood samples collected at 4 h intervals over a 24 h period once a month. Semen samples and testicular biopsies were also examined once a month. A well-defined circandian rhythm was evident in serum levels of testosterone. The rhythmicity was less pronounced in February and September. The 24 h mean levels of serum testosterone were high between the months of August to March and low in the months of May to July. All animals did not uniformly respond to electro-ejaculation in April and May. Semen volume and total number of spermatozoa were maximal between September and March and least from April to August. Testicular biopsies indicated that all stages of spermatogenesis were evident between September and March and the spermatogenic activity was less evident between April and August. The contents of Sertoli cells showed a seasonal cyclicity; they were laden with lipid droplets during April to August when spermatogenesis was quiescent and vacuolated during September to March when spermatogenesis was active. These studies indicate that the testing of contraceptive drugs needs to be restricted to months of September to March in male rhesus monkeys otherwise, it is possible that the naturally occurring reproductive quiscence may be attributed to the effect of the drug being tested. The data accrued from the present studies also provide quantitative information on circulating levels of testosterone which could be used as a reference background while evaluating the contraceptive drug-effects in male rhesus monkeys.     

Characterization of traumatic brain injury in human brains reveals distinct cellular and molecular changes in contusion and pericontusion

Traumatic brain injury (TBI) contributes to fatalities and neurological disabilities worldwide. While primary injury causes immediate damage, secondary events contribute to long‐term neurological defects. Contusions (Ct) are primary injuries correlated with poor clinical prognosis, and can expand leading to delayed neurological deterioration. Pericontusion (PC) (penumbra), the region surrounding Ct, can also expand with edema, increased intracranial pressure, ischemia, and poor clinical outcome. Analysis of Ct and PC can therefore assist in understanding the pathobiology of TBI and its management. This study on human TBI brains noted extensive neuronal, astroglial and inflammatory changes, alterations in mitochondrial, synaptic and oxidative markers, and associated proteomic profile, with distinct differences in Ct and PC. While Ct displayed petechial hemorrhages, thrombosis, inflammation, neuronal pyknosis, and astrogliosis, PC revealed edema, vacuolation of neuropil, axonal loss, and dystrophic changes. Proteomic analysis demonstrated altered immune response, synaptic, and mitochondrial dysfunction, among others, in Ct, while PC displayed altered regulation of neurogenesis and cytoskeletal architecture, among others. TBI brains displayed oxidative damage, glutathione depletion, mitochondrial dysfunction, and loss of synaptic proteins, with these changes being more profound in Ct. We suggest that analysis of markers specific to Ct and PC may be valuable in the evaluation of TBI pathobiology and therapeutics.