Genetic Diversity of Fusarium oxysporum f.sp. cubense Isolates (Foc) of India by Inter Simple Sequence Repeats (ISSR) Analysis

To find out the genetic diversity of Indian Foc isolates of banana, a total of 107 isolates of Fusarium which includes 98 Foc isolates obtained from different banana growing regions of India and seven Foc isolates belong to all known VCGs obtained from Australia and two non-pathogenic Fusarium oxysporum (npFo) isolates were subjected to ISSR analysis. In the initial screening of ISSR primers, out of 34, 10 primers which generated more polymorphic bands were selected for further analysis. The Phylogenetic analysis carried out based on the fingerprints obtained through ISSR analysis indicated the presence of wide genetic diversity among the Foc isolates of India and also its polyphyletic nature. Totally, seven different clusters were obtained and these clusters differentiated the Foc isolates of India based on the races/VCGs. Besides, the cluster analysis clearly distinguished the freshly emerged Foc strain obtained from cv. Grand Naine (Cavendish-AAA) and Poovan (Mysore-AAB) from the other Foc isolates. The non-pathogenic F. oxysporum isolates which have been included for comparison purpose also clustered separately. All these above said findings indicates for the first time the discriminatory power of ISSR to clearly distinguish and separate the Foc isolates according to its race/VCGs and also its virulence. This study would be useful not only to design and develop effective management strategies but also useful for quarantine purposes.     

Ursolic acid inhibits the initiation, progression of prostate cancer and prolongs the survival of TRAMP mice by modulating pro-inflammatory pathways

Prostate cancer is one of the leading causes of cancer death among men worldwide. In this study, using transgenic adenocarcinoma of mouse prostate (TRAMP) mice, the effect of diet enriched with 1% w/w ursolic acid (UA) was investigated to evaluate the stage specific chemopreventive activity against prostate cancer. We found that TRAMP mice fed with UA diet for 8 weeks (weeks 4 to 12) delayed formation of prostate intraepithelial neoplasia (PIN). Similarly, mice fed with UA diet for 6 weeks (weeks 12 to 18) inhibited progression of PIN to adenocarcinoma as determined by hematoxylin and eosin staining. Finally, TRAMP mice fed with UA diet for 12 weeks (weeks 24 to 36) demonstrated markedly reduced tumor growth without any significant effects on total body weight and prolonged overall survival. With respect to the molecular mechanism, we found that UA down-regulated activation of various pro-inflammatory mediators including, NF-κB, STAT3, AKT and IKKα/β phosphorylation in the dorsolateral prostate (DLP) tissues that correlated with the reduction in serum levels of TNF-α and IL-6. In addition, UA significantly down-regulated the expression levels of cyclin D1 and COX-2 but up-regulated the levels of caspase-3 as revealed by immunohistochemical analysis of tumor tissue sections. Finally, UA was detected in serum samples obtained from various mice groups fed with enriched diet in nanogram quantity indicating that it is well absorbed in the GI tract. Overall, our findings provide strong evidence that UA can be an excellent agent for both the prevention and treatment of prostate cancer.     

Extracellular enzymatic activity profiles in fungi isolated from oil-rich environments

About 34 wild fungal species associated with edible oil mill wastes were isolated by the serial dilution technique. Methods for rapid screening of fungal species against production of extracellular enzymes such as amylase, protease, cellulase, and lipase are reported. Among all the species, Aspergillus versicolor exhibited high amlylolytic and gelatinolytic activity, whereas Penicillium citrinum showed only high amylolytic activity. Maximum cellulolytic activity was recorded for Absidia corymbifera, As. niger, Cunninghamella echinulata, Curvularia lunata, Fusarium solani, Mucor racemosus, Paecilomyces variotii, and Syncephalastrum racemosum. The fungal species Ab. corymbifera, As. fumigatus, As. japonicus, As. nidulans, As. terreus, Cun. verticillata, Cur. pallescens, F. oxysporum, Geotrichum candidum, M. racemosus, Pe. citrinum, Pe. frequentans, Rhizopus stolonifer, and Trichoderma viride exhibited maximum lipase activity. This study confirms the isolated fungi present on a wide range of substrates in the ambient environment, and these results could provide basic data for further investigations on fungal extracellular enzymes.First two authors equally contributed to this work     

Effects of bulkiness and hydrophobicity of an aliphatic amino acid in the recognition helix of the GAGA zinc finger on the stability of the hydrophobic core and DNA binding affinity

The GAGA factor of Drosophila melanogaster uses a single Cys 2His 2-type zinc finger for specific DNA binding. The conformation and DNA binding mode of the GAGA zinc finger are similar to those of other structurally characterized zinc fingers. In almost all Cys 2His 2-type zinc fingers, the fourth position of the DNA-recognizing helix is occupied by the Leu residue involved in the formation of the minimal hydrophobic core. However, no systematic study on the precise role of the Leu residue in the hydrophobic core formation and DNA binding function has been reported. In this study, the Leu residue is substituted with other aliphatic amino acids having different side chain lengths and hydrophobicities, namely, Ile, Val, Aib, and Ala. The metal binding properties were studied by UV-vis spectroscopy. The peptide conformations were examined by CD and NMR spectroscopies. Furthermore, the DNA binding ability was examined with a gel mobility shift assay. Though the Ile, Val, and Aib mutants exhibited conformations similar to those of the wild type, the DNA binding affinity decreased as the side chain length of the amino acid decreased. Interestingly, the Val mutant can bind to the cognate DNA, while Aib cannot, in spite of the similarity in their secondary structures based on the CD measurements. Variable-temperature NMR experiments clearly indicated differences in the stability of the hydrophobic core between the Val and Aib mutants. This study demonstrates that the bulkiness of the conserved aliphatic residue is important in the formation of the well-packed minimal hydrophobic core and proper ternary structure and that the hydrophobic core stabilization is apparently related to the DNA binding function of the GAGA zinc finger.     

Effect of crude sulphated polysaccharide from brown algae against acetaminophen-induced toxicity in rats

This study was conducted to examine the protective role of crude polysaccharide from brown seaweed Sargassum polycystum against acetaminophen-induced abnormality in blood glucose, serum albumin/globulin ratio, and liver glycogen, lactate, and pyruvate. Liver and renal tissue histology was performed to confirm the efficacy of Sargassum polysaccharide. A toxic dose of acetaminophen (800 mg/kg body weight intraperitoneally) induced severe abnormality in all basic parameters with apparent toxicity in liver (enlargement of hepatocytes, loss of cytoplasmic content with disruption in the hepatic plates and sinusoidal dilation) and renal tissue (glomerular damage with congestion of tubules). The isolated liver cells were stained with acridine orange and examined under fluorescence microscope, which revealed that the acetaminophen induced significant damage. In contrast, the rats pretreated with Sargassum polysaccharide (200 mg/kg body weight) daily for 3 weeks did not show liver and renal tissue with these severe aberrations induced by acetaminophen. Histology results were also consistent with analyzed basic biochemical parameters, which confirmed the effectiveness of the crude polysaccharide against acetaminophen-induced abnormality in rats.     

Is reduced SERCA2a expression detrimental or beneficial to postischemic cardiac function and injury? Evidence from heterozygous SERCA2a knockout mice

Recent studies have demonstrated that increased expression of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) 2a improves myocardial contractility and Ca2+ handling at baseline and in disease conditions, including myocardial ischemia-reperfusion (I/R). Conversely, it has also been reported that pharmacological inhibition of SERCA might improve postischemic function in stunned hearts or in isolated myocardium following I/R. The goal of this study was to test how decreases in SERCA pump level/activity affect cardiac function following I/R. To address this question, we used a heterozygous SERCA2a knockout (SERCA2a+/-) mouse model with decreased SERCA pump levels and studied the effect of myocardial stunning (20-min ischemia followed by reperfusion) and infarction (30-min ischemia followed by reperfusion) following 60-min reperfusion. Our results demonstrate that postischemic myocardial relaxation was significantly impaired in SERCA2a+/- hearts with both stunning and infarction protocols. Interestingly, postischemic recovery of contractile function was comparable in SERCA2a+/- and wild-type hearts subjected to stunning. In contrast, following 30-min ischemia, postischemic contractile function was reduced in SERCA2a+/- hearts with significantly larger infarction. Rhod-2 spectrofluorometry revealed significantly higher diastolic intracellular Ca2+ in SERCA2a+/- hearts compared with wild-type hearts. Both at 30-min ischemia and 2-min reperfusion, intracellular Ca2+ levels were significantly higher in SERCA2a+/- hearts. Electron paramagnetic resonance spin trapping showed a similar extent of postischemic free-radical generation in both strains. These data provide direct evidence that functional SERCA2a level, independent of oxidative stress, is crucial for postischemic myocardial function and salvage during I/R.     

Isolation and characterization of melanin pigment from <Emphasis Type="Italic">Pleurotus cystidiosus</Emphasis> (telomorph of <Emphasis Type="Italic">Antromycopsis</Emphasis><Emphasis Type="Italic">macrocarpa</Emphasis>)

Melanins are enigmatic pigments that are produced by a wide variety of microorganisms including several species of bacteria and fungi. For more than 40 years, fungi have been known to produce pigments called melanins. Melanin pigment production by mushrooms was not intensively studied. The present study was carried out on isolation and characterization of melanin from an edible mushroom Pleurotus cystidiosus var. formosensis. The mushroom produced dark mucous mass of hyaline arthrospores on mycelium. The coremia exclusively produced dikaryotic arthrospores with the remnant of a clamp connection. Continuous cell extension and division in the coremium stipe supplied cells for arthroconidiation at the coremium apex, which is surrounded by a liquid droplet (coremioliquid). The black coloured coremea (conidia) were produced by Antromycopsis macrocarpa (anamorph of P. cystidiosus) when cultured on potato dextrose agar medium. The agar plate was incubated at continuous light illumination for high amount of pigment (coremea) production. The slimy layer of the coremea was extracted and partially purified by alkaline and acid treatment. The black pigment was confirmed as melanin based on UV, IR and EPR spectra apart from chemical analysis. This is the first report on characterization of melanin obtained from Pleurotus cystidiosus var. formosensis.     

Identification of Δ9-elongation activity from <Emphasis Type="Italic">Thraustochytrium aureum</Emphasis> by heterologous expression in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

The Δ9-elongase isolated from Thraustochytrium aureum, which contains a high level of polyunsaturated fatty acids (PUFAs), was demonstrated to be associated with the synthesis of C20 PUFAs. The TaELO gene contains a 825 bp ORF that encodes a protein of 274 amino acids that shares a high similarity with other PUFA elongases. The expression of the TaELO gene in Pichia pastoris resulted in the elongation of linoleic acid (LA, C18:2; n-6) and α-linolenic acid (ALA, C18:3; n-3) to eicosadienoic acid (EDA, C20:2; n-6) and eicosatrienoic acid (ETrA, C20:3; n-3), respectively. The endogenous conversion rate of LA and ALA to EDA and ETrA was 32.68 and 38.57%, respectively. In addition, TaELO was also able to synthesize eicosenoic acid (C20:1; n-9) from oleic acid (OA, C18:1; n-9), even though the conversion level was low (2.81%). Furthermore, TaELO was able to carry out the 6Δ-elongation of γ-linolenic acid (GLA, C18:3; n-6) to dihomo-γ-linolenic acid (DGLA, C20:3; n-6) and Δ5-elongation of eicosapentaenoic acid (EPA, C20:5; n-3) to docosapentaenoic acid (DPA, C22:5; n-3). The conversion rate of GLA to DGLA and EPA to DPA were 93 and 28.36%, respectively. The TaELO protein was confirmed to have multifunctional activities, such as Δ9, Δ6, and Δ5-elongations as well as the elongation of monounsaturated fatty acid.