Diversity of microorganisms in solar salterns of Tamil Nadu,India

In this study, the diversity of prokaryotes inhabiting crystallizer ponds of three solar salterns, located along Bengal Bay in Tamil Nadu, India was examined. Unlike other salterns studied the Tamil Nadu salterns are fed by hypersaline spring water mixed with seawater and led to the ponds from bore wells. In addition, prokaryotic community development is restricted as salterns operate only during the arid part of the year. Both culture-based and culture-independent polymerase chain reaction 16S rRNA molecular phylogenetic approaches were employed. Representatives of the family Halobacteriaceae dominated in cultivable portion of diversity encountered with members of genera Haloferax, Halorubrum, Haloarcula, Halobacterium and Halogeometricum recovered in pure culture. In contrast, members of Bacteria were recovered from only one sampling site and were represented by members of genera Salinibacter, Cytophaga and Marinococcus. Based on culture-independent sampling, the predominant members of the haloarchaeal crystallizer community belonged to the genus Natrinema.     

Curcumin prevents free radical-mediated cataractogenesis through modulations in lens calcium

The generation of free radicals has been implicated in the causation of cataract, and compounds that can scavenge free radicals ameliorate the disease process. This study investigated the possible free radical scavenging potential of curcumin at a dose of 75 mg/kg body wt on selenium-induced cataract in rat pups. Intraperitoneal injection of sodium selenite (15 μmol/kg body wt) into 8- to 10-day-old rat pups led to severe oxidative stress in the eye lens as evidenced by increased nitric oxide, superoxide anion, and hydroxyl radical generation and inducible nitric oxide synthase expression that probably led to cataract formation. Selenium exposure also caused an increase in total calcium in the eye lens and significantly inhibited the activity of Ca²⁺ ATPase but not Na⁺/K⁺ ATPase or Mg²⁺ ATPase. On the other hand, pretreatment with curcumin, but not simultaneous or posttreatment, led to a decrease in oxidative stress and also rescued the selenium-mediated increase in lens Ca²⁺ and inhibition of Ca²⁺ ATPase activity in the eye lens. The results of this study demonstrate that an increase in free radical generation triggered by selenium could cause inactivation of lens Ca²⁺ ATPase leading to Ca²⁺ accumulation. This enhanced Ca²⁺ can cause activation of calpain-mediated proteolysis in the lens, resulting in lens opacification. Curcumin in this study was able to prevent selenium-induced oxidative stress leading to activation of Ca²⁺ ATPase and inhibition of lens opacification. Thus, curcumin has the potential to function as an anticataractogenic agent, possibly by preventing free radical-mediated accumulation of Ca²⁺ in the eye lens.     

Biochemical changes in low-irradiance tolerant and susceptible rice cultivars

In the topmost leaves of low-irradiance (LI) tolerant CO 43 and LI susceptible IR 20 rice cultivars, the contents of chlorophyll (chl)a andb and carotenoids and the Hill reaction activity increased under LI. The increase was greater in cv. CO 43 than that in cv. IR 20, and in Chlb than in Chla. The contents of soluble proteins and reducing sugars and nitrate reductase activity of the leaves decreased while the content of non-reducing sugars increased due to shading. The decrease in reducing sugars was greater in cv. CO 43 than in cv. IR 20. On the other hand, the decrease in soluble proteins and nitrate reductase was much less in cv. CO 43 as compared with cv. IR 20. Communicated by Z. ŠESTáK     

Soluble cuticular phenoloxidase in the gypsy moth Lymantria dispar

The soluble enzyme phenoloxidase (tyrosinase) from the larval cuticle of Lymantria dispar has been partially purified using Ultrogel ACA 34, and the activity has been determined using phenolic substrates. The enzyme exhibited more activity toward O-diphenolic substrates and monophenolic substrates. The enzyme is inhibited by diethyl dithiocarbamate, phenylthiourea, and thiourea. The enzyme has been localized in the 7% slab and disc PAGE as an intense band. The enzyme is suggested to be involved in wound healing. © 1992 Wiley-Liss, Inc.     

Mitigation of cocaine-mediated mitochondrial damage,defective mitophagy and microglial activation by superoxide dismutase mimetics

ABSTRACT

Although cocaine exposure has been shown to potentiate neuroinflammation by upregulating glial activation in the brain, the role of mitophagy in this process remains an enigma. In the present study, we sought to examine the role of impaired mitophagy in cocaine-mediated activation of microglia and to determine the ameliorative potential of superoxide dismutase mimetics in this context. Our findings demonstrated that exposure of mouse primary microglial cells (mPMs) to cocaine resulted in decreased mitochondrial membrane potential, that was accompanied by increased expression of mitophagy markers, PINK1 and PRKN. Exposure of microglia to cocaine also resulted in increased expression of DNM1L and OPTN with a concomitant decrease in the rate of mitochondrial oxygen consumption as well as impaired mitochondrial functioning. Additionally, in the presence of cocaine, microglia also exhibited upregulated expression of autophagosome markers, BECN1, MAP1LC3B-II, and SQSTM1. Taken together, these findings suggested diminished mitophagy flux and accumulation of mitophagosomes in the presence of cocaine. These findings were further confirmed by imaging techniques such as transmission electron microscopy and confocal microscopy. Cocaine-mediated activation of microglia was further monitored by assessing the expression of the microglial marker (ITGAM) and the inflammatory cytokine (Tnf, Il1b, and Il6) mRNAs. Pharmacological, as well as gene-silencing approaches aimed at blocking both the autophagy/mitophagy and SIGMAR1 expression, underscored the role of impaired mitophagy in cocaine-mediated activation of microglia. Furthermore, superoxide dismutase mimetics such as TEMPOL and MitoTEMPO were shown to alleviate cocaine-mediated impaired mitophagy as well as microglial activation.

Abbreviations: 3-MA: 3-methyladenine; Δψm: mitochondrial membrane potential; ACTB: actin, beta; AIF1: allograft inflammatory factor 1; ATP: adenosine triphosphate; BAF: bafilomycin A₁; BECN1: beclin 1, autophagy related; CNS: central nervous system; DNM1L: dynamin 1 like; DMEM: Dulbecco modified Eagle medium; DAPI: 4,6-Diamidino-2-phenylindole; DRD2: dopamine receptor D2; ECAR: extracellular acidification rate; FBS: fetal bovine serum; FCCP: Trifluoromethoxy carbonylcyanide phenylhydrazone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; IL1B: interleukin 1, beta; IL6: interleukin 6; ITGAM: integrin subunit alpha M; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; mPMs: mouse primary microglial cells; MRC: maximal respiratory capacity; NFKB: nuclear factor kappa B; NLRP3: NLR family pyrin domain containing 3; NTRK2: neurotrophic receptor tyrosine kinase 2; OCR: oxygen consumption rate; OPTN: optineurin; PBS: phosphate buffered saline; PINK1: PTEN induced putative kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; siRNA: small interfering RNA; SQSTM1: sequestosome 1; TNF: tumor necrosis factor     

Phenoloxidase activity and its rôle in cuticular sclerotization in a mole crab Emerita asiatica Milne Edwards

Phenoloxidase has been localized in the epicuticle, exocuticle, and epidermal cells of the mole crab, Emerita asiatica Milne Edwards. The enzyme activity in different moulting stages is in the order of freshmoult > premoult > intermoult = postmoult. The phenoloxidase of the freshmoult cuticle oxidizes pyrogallol and epinephrine (adrenaline) more effectively than the other phenols studied. There is no monophenolase activity. The possible metabolic pathway has been suggested based on the specificity of the enzyme and the chromatographic identification of the extracted phenols. Phenoloxidase shows different pH optima in different buffers. The protein pattern in the various moulting stages of the cuticle differs and the results are discussed in relation to sclerotization.