Antioxidant role of zinc in PCB (Aroclor 1254) exposed ventral prostate of albino rats

The ability of zinc to retard oxidative processes has been recognized for many years. Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental toxicants. Previous study has indicated that PCBs can have deleterious effects, including oxidative stress, on various aspects of reproduction in male rats. The aim of this study was to determine the antioxidant role of zinc in PCB-exposed ventral prostate of albino rats. A group of 20 rats were treated with Aroclor 1254 (2 mg/kg body weight/day, i.p.) for 30 days. After the PCB treatment, 10 rats were treated as PCB control. The remaining 10 rats were given zinc (Zn SO(4)) (200 mg/kg body weight/day, p.o.) for 10 days. Ventral prostatic enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) were estimated in all the groups. Hydrogen peroxide (H(2)O(2)), lipid peroxidation (LPO) and ventral prostatic acid phosphatase (ACP) were also estimated. Serum hormonal profiles such as total tri-iodothyronine (T(3)), thyroxine (T(4)), thyroid stimulating hormone (TSH), testosterone, and estradiol were estimated. Ventral prostatic androgen and estrogen receptors, ventral prostatic zinc content, and serum zinc concentration were also quantified in all the groups. Antioxidant enzymes such as SOD, CAT, GPx, GST, and ACP were decreased while an increase in H(2)O(2) and LPO were observed in PCB-treated animals. Decreased serum total T(3), T(4), testosterone, estradiol and increased TSH were observed in PCB-exposed rats. Ventral prostatic androgen and estrogen receptors were also decreased significantly in PCB-exposed rats. Zinc administration restored to previous levels all parameters except ventral prostatic ACP. These results suggest that PCB induces oxidative stress in rat ventral prostate by decreasing the levels of antioxidant enzymes; the effects could be reversed by the administration of zinc. The adverse effect of PCBs (Aroclor 1254) and zinc on ventral prostate might be due to indirect action through hormonal regulation.     

Cross-species identification of PIP5K1-, splicing- and ubiquitin-related pathways as potential targets for RB1-deficient cells

The RB1 tumor suppressor is recurrently mutated in a variety of cancers including retinoblastomas, small cell lung cancers, triple-negative breast cancers, prostate cancers, and osteosarcomas. Finding new synthetic lethal (SL) interactions with RB1 could lead to new approaches to treating cancers with inactivated RB1. We identified 95 SL partners of RB1 based on a Drosophila screen for genetic modifiers of the eye phenotype caused by defects in the RB1 ortholog, Rbf1. We validated 38 mammalian orthologs of Rbf1 modifiers as RB1 SL partners in human cancer cell lines with defective RB1 alleles. We further show that for many of the RB1 SL genes validated in human cancer cell lines, low activity of the SL gene in human tumors, when concurrent with low levels of RB1 was associated with improved patient survival. We investigated higher order combinatorial gene interactions by creating a novel Drosophila cancer model with co-occurring Rbf1, Pten and Ras mutations, and found that targeting RB1 SL genes in this background suppressed the dramatic tumor growth and rescued fly survival whilst having minimal effects on wild-type cells. Finally, we found that drugs targeting the identified RB1 interacting genes/pathways, such as UNC3230, PYR-41, TAK-243, isoginkgetin, madrasin, and celastrol also elicit SL in human cancer cell lines. In summary, we identified several high confidence, evolutionarily conserved, novel targets for RB1-deficient cells that may be further adapted for the treatment of human cancer.     

The relationship between airway immunoglobulin activity and eosinophils in COPD

In chronic obstructive pulmonary disease (COPD), the effects of inhaled corticosteroids are predicted by blood eosinophil counts. We previously briefly reported increased immunoglobulin (Ig)A and IgM levels in bronchoalveolar lavage (BAL) of COPD patients with higher (eosinophil^high) compared to lower (eosinophil^low) blood eosinophils (>250/μL versus < 150/μL), suggesting differences in adaptive immune function. An inverse relationship exists between eosinophil counts and airway pathogenic bacteria levels. The mechanistic reasons for these associations between eosinophils, corticosteroids and pathogenic bacteria are unclear. IgA, IgM and IgG levels were assessed in BAL, bronchial biopsies and epithelium collected from eosinophil^high (n = 20) and eosinophil^low (n = 21) patients. Bronchial B-cell numbers were measured by immunohistochemistry. B-cell activity was assessed in bronchial samples and following exposure to BAL from eosinophil^high and eosinophil^low patients. BAL levels of non-typeable Haemophilus influenza (NTHi)-specific immunoglobulins were quantified. Results showed airway expression of IgA, IgG1 and IgM were lower in eosinophil^low compared to eosinophil^high patients, with lower levels of NTHi-specific IgA and IgM. Bronchial B-cell numbers were similar in both groups, but B-cell activity was lower in eosinophil^low patients. In conclusion, COPD eosinophil^low patients show differences in adaptive immune function compared to COPD eosinophil^high patients. These differences may cause different microbiomes in these COPD phenotypes.     

Efforts toward the first total synthesis of a mixed-ligand siderophore: Gobichelin-A

The synthesis of Gobichelin-A, a naturally occurring mixed-ligand siderophore isolated from Streptomyces sp. NRRL F-4415, is described. The target molecule was planned to be synthesized by a convergent process involving the combination of two halves, Gob-A 1st half and Gob-A 2nd half, at the prefinal stage of the synthetic route. By adopting this method, fully protected Gobichelin-A was synthesized in excellent yield.     

sRNAbase: A Web Resource for Small RNAs in Enterobacteriaceae\m{1}

Bacterial small RNAs (sRNAs) have gained considerable attention due to their multivalent roles in the survival and pathogenesis of bacteria and mostly identified through bio-computational methods. A manually curated web-resource, sRNAbase has been constructed to give comprehensive and exhaustive information on non-coding small RNAs excluding tRNAs and rRNAs in Enterobacteriaceae family. The sRNA entries curated in sRNAbase contain experimentally verified small RNAs available in the literature and their partial/non-homologs reported within the related genomes from our earlier studies. The sRNAbase aims to facilitate the scientific community by providing information on the physical genomic location of the non-coding small RNAs, its alias names, sequences, strand orientation, gene identification numbers of the conserved genes that sandwiches the particular sRNA with possible functional role and a link to the PubMed literatures. Currently, sRNAbase holding information on 1986 entries belongs to 80 sRNA families spread over 45 Enterobacteriaceae genomes. The sRNAbase is accessible on the web at http://bicmku.in:8081/srnabase/.     

Mice primed with swainsonine are protected against doxorubicin-induced lethality.

The anthracycline, doxorubicin is a potent cancer chemotherapeutic agent whose therapeutic usefulness is limited by both a dose- and time-dependent cardiomyopathy. We tested the ability of an immunomodulatory alkaloid swainsonine (8alphabeta-indolizidine-1alpha,2alpha,8beta-triol) to protect C57BL/6 mice against lethality within 70 days following a single bolus intraperitoneal injection of LD50/14 doxorubicin. Also, we sought the potential mechanisms responsible for this protection. This extended 70-day study in mice, which may be considered equivalent to a period of 4 to 5 years in humans, has clinical implication for delayed cardiotoxic sequela of therapy with high dose doxorubicin. Mice were pretreated with swainsonine or its diluent buffer, phosphate buffered saline for ten consecutive days prior to a single bolus intraperitoneal injection of a LD50/14 doxorubicin. We have previously defined this swainsonine pretreatment regimen as one of the two optimal conditions for swainsonine rescue of mice from death induced by LD50/14 doxorubicin. The survival and well being of groups of mice pretreated with swainsonine and phosphate buffered saline prior to LD50/14 doxorubicin, sham-treated and untreated were monitored daily for up to 70 days. The bone marrow cellularity of the mice were quantified, and in vitro progenitor cell assays were used to determine the effects of these treatment regimens on bone marrow competence following doxorubicin treatment. The effects of these treatment regimens on heart morphology and hematologic toxicities were also determined. This swainsonine pretreatment regimen significantly abrogated doxorubicin-induced lethality and prolonged survival of mice by facilitating restoration of bone marrow cellularity, accelerating restoration of blood hematocrit and total leukocyte levels, enhancing the proliferation and differentiation of bone marrow pluripotent stem cells along the different paths to progenitor lineages, and preserving the heart morphology. This study strongly suggests a potential role for swainsonine with doxorubicin in cancer chemotherapy.     

Design of disulfide-linked thioredoxin dimers and multimers through analysis of crystal contacts

Disulfide bonds play an important role in protein stability and function. Here, we describe a general procedure for generating disulfide-linked dimers and multimers of proteins of known crystal structures. An algorithm was developed to predict sites in a protein compatible with intermolecular disulfide formation with neighboring molecules in the crystal lattice. A database analysis was carried out on 46 PDB coordinates to verify the general applicability of this algorithm to predict intermolecular disulfide linkages. On the basis of the predictions from this algorithm, mutants were constructed and characterized for a model protein, thioredoxin. Of the five mutants, as predicted, in solution four formed disulfide-linked dimers while one formed polymers. Thermal and chemical denaturation studies on these mutant thioredoxins showed that three of the four dimeric mutants had similar stability to wild-type thioredoxin while one had lower stability. Three of the mutant dimers crystallized readily (in four to seven days) in contrast to the wild-type protein, which is particularly difficult to crystallize and takes more than a month to form diffraction-quality crystals. In two of the three cases, the structure of the dimer was exactly as predicted by the algorithm, while in the third case the relative orientation of the monomers in the dimer was different from the predicted one. This methodology can be used to enhance protein crystallizability, modulate the oligomerization state and to produce linear chains or ordered three-dimensional protein arrays.     

Mechanisms of impaired calcium handling underlying subclinical diastolic dysfunction in diabetes

Isolated diastolic dysfunction is found in almost half of asymptomatic patients with well-controlled diabetes and may precede diastolic heart failure. However, mechanisms that underlie diastolic dysfunction during diabetes are not well understood. We tested the hypothesis that isolated diastolic dysfunction is associated with impaired myocardial Ca(2+) handling during type 1 diabetes. Streptozotocin-induced diabetic rats were compared with age-matched placebo-treated rats. Global left ventricular myocardial performance and systolic function were preserved in diabetic animals. Diabetes-induced diastolic dysfunction was evident on Doppler flow imaging, based on the altered patterns of mitral inflow and pulmonary venous flows. In isolated ventricular myocytes, diabetes resulted in significant prolongation of action potential duration compared with controls, with afterdepolarizations occurring in diabetic myocytes (P < 0.05). Sustained outward K(+) current and peak outward component of the inward rectifier were reduced in diabetic myocytes, while transient outward current was increased. There was no significant change in L-type Ca(2+) current; however, Ca(2+) transient amplitude was reduced and transient decay was prolonged by 38% in diabetic compared with control myocytes (P < 0.05). Sarcoplasmic reticulum Ca(2+) load (estimated by measuring the integral of caffeine-evoked Na(+)-Ca(2+) exchanger current and Ca(2+) transient amplitudes) was reduced by approximately 50% in diabetic myocytes (P < 0.05). In permeabilized myocytes, Ca(2+) spark amplitude and frequency were reduced by 34 and 20%, respectively, in diabetic compared with control myocytes (P < 0.05). Sarco(endo)plasmic reticulum Ca(2+)-ATPase-2a protein levels were decreased during diabetes. These data suggest that in vitro impairment of Ca(2+) reuptake during myocyte relaxation contributes to in vivo diastolic dysfunction, with preserved global systolic function, during diabetes.     

Synthesis, structure analysis, and antibacterial activity of some novel 10-substituted 2-(4-piperidyl/phenyl)-5,5-dioxo[1,2,4]triazolo[1,5-b][1,2,4]benzothiadiazine derivatives

A new series of 10-substituted 5,5-dioxo-5,10-dihydro[1,2,4]triazolo[1,5-b]-[1,2,4]benzothiadiazine arylsulfonamide derivatives (10a-j and 13a-f) was synthesized. The structures of these compounds were confirmed on the basis of spectral data, elemental analysis, X-ray analysis, and quantum chemical calculations. These compounds were evaluated for their efficacy as antibacterial agents against various Gram-positive and Gram-negative strains of bacteria. Amongst these compounds 10f and 10i were the most active compounds against Escherichia coli and 13e against E. coli as well as Bacillus subtilis. Moreover, other compounds also showed potent inhibitory activity in comparison to the standard drugs.