Decolorization of Textile Dyes and Degradation of Mono-Azo Dye Amaranth by <Emphasis Type="Italic">Acinetobacter calcoaceticus</Emphasis> NCIM 2890

Acinetobacter calcoaceticus NCIM 2890 (A. caloaceticus) was found to decolorize 20 different textile dyes of various classes. Decolorization of an azo dye amaranth was observed effectively (91%) at static anoxic condition, whereas agitated culture grew well but showed less decolorization (68%) within 48 h of incubation. Induction of intracellular and extracellular lignin peroxidase, intracellular laccase, dichlorophenol indophenol (DCIP) reductase and riboflavin reductase represented their involvement in the biodegradation of amaranth. The products obtained after degradation of Amaranth were characterized as naphthalene sulfamide, hydroxyl naphthalene diazonium and naphthalene diazonium. The germination and growth of Sorghum vulgare and Phaseolus mungo seeds, and the growth of E. coli and Bacillus substilis were not inhibited by the metabolic products of the dye.     

Sphingolipid storage impairs autophagic clearance of Alzheimer-associated proteins

Recent work from our laboratory demonstrates that the accumulation of sphingolipids (SLs) decreases the capacity of cells to clear potentially amyloidogenic fragments of the amyloid precursor protein (APP) during autophagy. APP is a type I membrane protein and could undergo sequential proteolytic processing by β- and γ-secretase resulting in the generation of the amyloid β-peptide (Aβ). Genetic, molecular and biochemical evidence indicates that the accumulation of toxic Aβ aggregates plays a critical role in the degeneration of neurons during the pathogenesis of Alzheimer disease (AD). Thus, SL storage could promote the accumulation of Ab in endosomal and lysosomal compartments and thereby induce characteristic cytopathological changes of AD.     

Synthesis of chalcone-amidobenzothiazole conjugates as antimitotic and apoptotic inducing agents

A series of chalcone-amidobenzothiazole conjugates (9a-k and 10a,b) have been synthesized and evaluated for their anticancer activity. All these compounds exhibited potent activity and the IC(50) of two potential compounds (9a and 9f) against different cancer cell lines are in the range of 0.85-3.3 μM. Flow cytometric analysis revealed that these compounds induced cell cycle arrest at G2/M phase in A549 cell line leading to caspase-3 dependent apoptotic cell death. The tubulin polymerization assay (IC(50) of 9a is 3.5 μM and 9f is 5.2 μM) and immuofluorescence analysis showed that these compounds effectively inhibit microtubule assembly at both molecular and cellular levels in A549 cells. Further, Annexin staining also suggested that these compounds induced cell death by apoptosis. Moreover, docking experiments have shown that they interact and bind efficiently with tubulin protein. Overall, the current study demonstrates that the synthesis of chalcone-amidobenzothiazole conjugates as promising anticancer agents with potent G2/M arrest and apoptotic-inducing activities via targeting tubulin.     

Interaction of Melanin with Proteins – The Importance of an Acidic Intramelanosomal pH

Melanin is a highly irregular heteropolymer consisting of monomeric units derived from the enzymatic oxidation of the amino acid tyrosine. The process of melanin formation takes place in specialized acidic organelles (melanosomes) in melanocytes. The process of melanin polymerization requires an alkaline pH in vitro, and therefore, the purpose of an acidic environment in vivo remains a mystery. It is known that melanin is always bound to protein in vivo. It is also seen that polymerization in vitro at an acidic pH necessarily requires the presence of proteins. The effect of various model proteins on melanin synthesis and their interaction with melanin was studied. It was seen that many proteins could increase melanin synthesis at an acidic pH, and that different proteins resulted in the formation of different states of melanin, i.e., a precipitate or a soluble, protein‐bound form. We also present evidence to show that soluble protein‐bound melanin is present in vivo (in B16 cells as well as in B16 melanoma tissue). An acidic pH appeared to be necessary to ensure the formation of a uniform, very high molecular weight melano–protein complex. The interaction between melanin and proteins appears to be largely charge‐dependent as evidenced by zeta potential measurements, and this interaction is also increased in an acidic pH. Thus, it appears that an acidic intramelanosomal pH is essential to ensure maximum interaction between protein and melanin, and also to ensure that all the melanin formed is protein‐bound.     

Lipoprotein Profiles in Class III Obese Caucasian and African American Women with Nonalcoholic Fatty Liver Disease

Triglyceride content in the liver is regulated by the uptake, production and elimination of lipoproteins, and derangements in these processes contribute to nonalcoholic fatty liver disease (NAFLD). Previous studies show a direct relationship between intrahepatic fat and production of apolipoprotein B100 (apoB100) containing particles, VLDL and LDL, but little consensus exists regarding changes in lipoprotein production in the development of simple steatosis (SS) versus nonalcoholic steatohepatitis (NASH). Further, ethnic variations in lipoproteins among SS and NASH are unknown as is how such variations might contribute to the differential prevalence of disease among Caucasians versus African Americans. In this study, we assessed plasma lipoprotein profiles by nuclear magnetic resonance (NMR) spectroscopy in 70 non-diabetic class III obese females recruited from the surgical weight loss clinic. Of these, 51 females were stratified by biopsy-staged NAFLD severity (histologically normal, SS, or NASH). NASH females displayed increased circulating triglycerides and increased VLDL particle number and size relative to those with histologically normal livers, while total and large LDL concentration decreased in SS versus NASH and correlated with increased insulin resistance (via HOMA2-IR). When Caucasian women were examined alone (n = 41), VLDL and triglycerides increased between normal and SS, while total LDL and apoB100 decreased between SS and NASH along with increased insulin resistance. Compared to Caucasians with SS, African American women with SS displayed reduced triglycerides, VLDL, and small LDL and a more favorable small to large HDL ratio despite having increased BMI and HOMA2-IR. These findings suggest that ApoB100 and lipoprotein subclass particle number and size can delineate steatosis from NASH in obese Caucasian females, but should be interpreted with caution in other ethnicities as African Americans with SS display relatively improved lipoprotein profiles. This may reflect variation in the relationship between dyslipidemia and NAFLD progression across gender and ethnicity.     

Decolorization and detoxification of Congo red and textile industry effluent by an isolated bacterium <Emphasis Type="Italic">Pseudomonas</Emphasis> sp. SU-EBT

The 16S rRNA sequence and biochemical characteristics revealed the isolated organism as Pseudomonas sp. SU-EBT. This strain showed 97 and 90% decolorization of a recalcitrant dye, Congo red (100 mg l⁻¹) and textile industry effluent with 50% reduction in COD within 12 and 60 h, respectively. The optimum pH and temperature for the decolorization was 8.0 and 40°C, respectively. Pseudomonas sp. SU-EBT was found to tolerate the dye concentration up to 1.0 g l⁻¹. Significant induction in the activity of intracellular laccase suggested its involvement in the decolorization of Congo red. The metabolites formed after decolorization of Congo red, such as p-dihydroxy biphenyl, 8-amino naphthol 3-sulfonic acid and 3-hydroperoxy 8-nitrosonaphthol were characterized using FTIR and GC–MS. Phytotoxicity study revealed nontoxic nature of the degradation metabolites to Sorghum bicolor, Vigna radiata, Lens culinaris and Oryza sativa plants as compared to Congo red and textile industry effluent. Pseudomonas sp. SU-EBT decolorized several individual textile dyes, dye mixtures and textile industry effluent, thus it is a useful strain for the development of effluent treatment methods in textile processing industries.     

Alpha-amylase inhibitors from mycelium of an oyster mushroom

Abstract

The α-Amylase and α-glucosidase are two main enzymes involved in carbohydrate metabolism. This study was aimed at detecting alpha-amylase inhibitory activity from edible mushroom mycelia. Oyster mushroom was collected from a natural source, from Indian Institute of Technology (Banaras Hindu University) campus and was maintained in vitro in mycelial form. Chloroform, acetone, methanol, and water were used separately for extraction of an active constituent from mycelial cells grown, for 7?days, in potato dextrose broth. The extracts were tested for alpha-amylase inhibitory activity. Chloroform, acetone, and methanol extracts were found to have alpha-amylase inhibitory activity, with IC₅₀ values of 1.71, 224, and 383?μg/mL, respectively. Aqueous extract had no enzyme inhibitory activity. The acetone extract inhibited α-amylase non-competitively whereas chloroform extract showed competitive inhibition. Acetone extraction yielded highest total phenolic content (TPC) of 0.524?mM of gallic acid equivalent, whereas chloroform extraction resulted in lowest TPC of 0.006?mM. The HPLC and absorbance maxima of acetone and chloroform extracts suggest that the bioactive component responsible for enzyme inhibition could be glycoproteins in chloroform extract and catechins (flavonoids) in acetone extract. Thus, the mushroom mycelia under study may be exploited for production and purification of a lead compound for the development of the α-amylase inhibitory drug.     

Synthesis and anticancer activity of heteroaromatic linked 4β-amido podophyllotoxins as apoptotic inducing agents

A series of different heteroaromatic linked 4β-amidopodophyllotoxin conjugates (16a–i, 17a–i and 18a–d) were synthesized and evaluated for anticancer activity against five human cancer cell lines. Among the series, one of the compound 17g showed significant antiproliferative activity in A549 (lung cancer) cell line. Flow cytometric analysis showed that 17g arrested the cell cycle in the G2/M phase leading to caspase-3 dependent apoptotic cell death. Further, Hoechst 33258 staining and DNA fragmentation assay also suggests that 17g induces cell death by apoptosis.     

Impaired infectivity of ritonavir-resistant HIV is rescued by heat shock protein 90AB1

Certain ritonavir resistance mutations impair HIV infectivity through incomplete Gag processing by the mutant viral protease. Analysis of the mutant virus phenotype indicates that accumulation of capsid-spacer peptide 1 precursor protein in virus particles impairs HIV infectivity and that the protease mutant virus is arrested during the early postentry stage of HIV infection before proviral DNA synthesis. However, activation of the target cell can rescue this defect, implying that specific host factors expressed in activated cells can compensate for the defect in ritonavir-resistant HIV. This ability to rescue impaired HIV replication presented a unique opportunity to identify host factors involved in postentry HIV replication, and we designed a functional genetic screen so that expression of a given host factor extracted from activated T cells would lead directly to its discovery by rescuing mutant virus replication in nonactivated T cells. We identified the cellular heat shock protein 90 kDa α (cytosolic), class B member 1 (HSP90AB1) as a host factor that can rescue impaired replication of ritonavir-resistant HIV. Moreover, we show that pharmacologic inhibition of HSP90AB1 with 17-(allylamino)-17-demethoxygeldanamycin (tanespimycin) has potent in vitro anti-HIV activity and that ritonavir-resistant HIV is hypersensitive to the drug. These results suggest a possible role for HSP90AB1 in postentry HIV replication and may provide an attractive target for therapeutic intervention.