A new fluorescent chemosensor for cadmium(II) based on a pyrene‐appended piperidone derivative and its β‐cyclodextrin complex

We report, in this article, a piperidin‐4‐one derivative carrying pyrenyl fluorescent reporter groups which acts as a Cd²⁺ ion sensor. The compound is synthesized and characterized using IR and NMR spectral techniques. The compound forms an inclusion complex with β‐cyclodextrin. It selectively binds to Cd²⁺ ions in water and aqueous β‐cyclodextrin media. The stoichiometry of the host–guest complex of the compound with β‐cyclodextrin is 1:2. The ligand–metal ion binding stoichiometry is 1:1 both in water and in β‐cyclodextrin. The linear concentration range of detection of the metal ion is reported. Cyclodextrin complex formation does not affect the metal ion selectivity of the compound.     

Keratins regulate protein biosynthesis through localization of GLUT1 and -3 upstream of AMP kinase and Raptor

Keratin intermediate filament proteins form cytoskeletal scaffolds in epithelia, the disruption of which affects cytoarchitecture, cell growth, survival, and organelle transport. However, owing to redundancy, the global function of keratins has not been defined in full. Using a targeted gene deletion strategy, we generated transgenic mice lacking the entire keratin multiprotein family. In this study, we report that without keratins, embryonic epithelia suffer no cytolysis and maintain apical polarity but display mislocalized desmosomes. All keratin-null embryos die from severe growth retardation at embryonic day 9.5. We find that GLUT1 and -3 are mislocalized from the apical plasma membrane in embryonic epithelia, which subsequently activates the energy sensor adenosine monophosphate kinase (AMPK). Analysis of the mammalian target of rapamycin (mTOR) pathway reveals that AMPK induction activates Raptor, repressing protein biosynthesis through mTORC1''s downstream targets S6 kinase and 4E-binding protein 1. Our findings demonstrate a novel keratin function upstream of mTOR signaling via GLUT localization and have implications for pathomechanisms and therapy approaches for keratin disorders and the analysis of other gene families.     

Evaluation of antihyperlipidemic activity of ethanolic extract of Cassia auriculata flowers

Hyperlipidemia is a major risk factor for development of coronary artery disease. Cassia auriculata is traditionally used in India for medicinal purposes. In this study, effect of ethanolic extract of Cassia auriculata flowers (Et-CAF) was investigated in Triton WR1339-induced hyperlipidemic rats. Treatment with the Et-CAF (450 mg/kg b.wt) significantly reduced the total cholesterol (TC), triglycerides (TG) and low-density lipoprotein-cholesterol (LDL) levels and significantly increased the high-density lipoprotein (HDL) level associated with reduction of atherogenic index in hyperlipidemic rats. However, there was no change in the serum lipid profile of normal rats treated with Et-CAF alone. The results suggest that Et-CAF has a beneficial effect in treating hyperlipidemia and may serve as a potential drug for prevention of hyperlipidemic atherosclerosis.     

A direct interaction between NQO1 and a chemotherapeutic dimeric naphthoquinone

Background

Multimeric naphthoquinones are redox-active compounds that exhibit antineoplastic, antiprotozoal, and antiviral activities. Due to their multimodal effect on perturbation of cellular oxidative state, these compounds hold great potential as therapeutic agents against highly proliferative neoplastic cells. In our previous work, we developed a series of novel dimeric naphthoquinones and showed that they were selectively cytotoxic to human acute myeloid leukemia (AML), breast and prostate cancer cell lines. We subsequently identified the oxidoreductase NAD(P)H dehydrogenase, quinone 1 (NQO1) as the major target of dimeric naphthoquinones and proposed a mechanism of action that entailed induction of a futile redox cycling.

Results

Here, for the first time, we describe a direct physical interaction between the bromohydroxy dimeric naphthoquinone E6a and NQO1. Moreover, our studies reveal an extensive binding interface between E6a and the isoalloxazine ring of the flavin adenine dinucleotide (FAD) cofactor of NQO1 in addition to interactions with protein side chains in the active site. We also present biochemical evidence that dimeric naphthoquinones affect the redox state of the FAD cofactor of NQO1. Comparison of the mode of binding of E6a with those of other chemotherapeutics reveals unique characteristics of the interaction that can be leveraged in future drug optimization efforts.

Conclusion

The first structure of a dimeric naphthoquinone-NQO1 complex was reported, which can be used for design and synthesis of more potent next generation dimeric naphthoquinones to target NQO1 with higher affinity and specificity.

     

Kinetics of leather dyeing pretreated with enzymes: Role of acid protease

In the present investigation, kinetics of dyeing involving pretreatment with acid protease has been presented. Application of acid protease in dyeing process resulted in increased absorption and diffusion of dye into the leather matrix. Enzyme treatment at 1% concentration, 60 min duration and 50 °C resulted in maximum of 98% dye exhaustion and increased absorption rate constants. The final exhaustion (C_∞) for the best fit of CI Acid Black 194 dye has been 98.5% with K and r² values from the modified Cegarra-Puente isotherm as 0.1033 and 0.0631. CI Acid Black 194 being a 2:1 metal complex acid dye exhibited higher absorption rate than the acid dye CI Acid Black 210. A reduction in 50% activation energy calculated from Arrhenius equation has been observed in enzyme assisted dyeing process of both the dyes that substantiates enhanced dye absorption. The absorption rate constant calculated with modified Cegarra-Puente equation confirm higher rate constants and faster kinetics for enzyme assisted dyeing process. Enzyme treated leather exhibited richness of color and shade when compared with control. The present study substantiates the essential role of enzyme pretreatment as an eco-friendly leather dyeing process.     

Induction of acute respiratory distress syndrome in rats by lipopolysaccharide and its effect on oxidative stress and antioxidant status in lung

Acute lung injury (ALI) or its severe form, acute respiratory distress syndrome (ARDS) is an important cause of mortality in the human population. Despite significant advances made, the mortality associated with ALI remains unchanged. The objective of the present study was to evaluate the role of oxidative stress, alveolar antioxidant status and multiple organ injury in ARDS induced by lipopolysaccharide (LPS) in rats. Rats were divided into 4 groups, group I control rats were given saline intraperitoneally, whereas groups II, III and IV (LPS-treated) rats received an intraperitoneal injection of LPS (10 mg/kg body weight) and sacrificed after various time intervals. In LPS-treated rats, we observed increased levels of oxidative products, decreased levels of antioxidants in lung tissues and increased levels of serum marker enzymes, suggesting multiple organ injury. Bronchoalveolar lavage fluid (BALF) neutrophil content and protein concentration in LPS-treated rats were significantly elevated in a time-dependent manner. Histological studies revealed neutrophil influx and diffused alveolar damage in LPS-administered rats. These results clearly suggested that increased oxidant levels led to oxidative stress, antioxidant deficiency attenuating lung inflammation and tissue damage. LPS administration resulted in multiple organ failure, leading to increased mortality.     

Degradation of <Emphasis Type="Italic">Saccharomyces cervisiae</Emphasis> Rck2 upon exposure of cells to high levels of zinc is dependent on Pep4

In undisturbed cells, the MAPK-activated protein kinase Rck2 of Saccharomyces cerevisiae is a stable protein with a turnover time exceeding 60 min. However, we have found that Rck2 is subject to intracellular degradation after exposure of cells to Zn²⁺ concentrations of 5 mM or more. In high-zinc medium, most of the Rck2 pool is degraded within 5 min. This degradation is blocked by inhibiting the vacuolar proteolytic pathway with the protease inhibitor phenyl methyl sulphonyl fluoride or by mutation of the PEP4 gene. By contrast, blocking the proteasomal pathway with the inhibitor MG132 does not prevent Rck2 degradation upon addition of Zn²⁺, nor is degradation inhibited in the proteasomal mutations pre1 pre2, cim3, or cim5. The stability of Rck2 is not affected by any of the other stress conditions examined, or by growth rate. Possible mechanisms of the degradation of Rck2 under high zinc conditions, and its physiological significance, are discussed.     

Y chromosome microdeletions in infertile males from Andhra Pradesh, South India

Studies on the frequency of Y chromosome microdeletions were carried out in 70 idiopathic infertile males with normal karyotypes. Genomic DNA was isolated from blood and PCR analysis was carried out with AZFa, AZFb, and AZFc STS markers SY 84, SY 87, SY 127, SY 254, and SY 158 to detect the deletions. In 9/70 (12.8%) subjects AZF deletions were observed. In 4/9 (44.4%) subjects were azoospermic, 4/9 (44.4%) of cases were severe oligozoospermic, and 1/9 (11.1%) cases was oligozoospermic.