Partial Characterization of Small Plasmids fromCorynebacterium renale

A naphthalene-degrading strain of corynebacteria, Corynebacterium renale, harbors multiple small plasmids designated pCR1, pCR2, pCR3, and pCR4 with sizes of 1.4, 3.2, 4.4, and 5.7 kb, respectively. Plasmid pCR1 of 1.4 kb is the smallest plasmid reported in this group of bacteria and is present in high copy number. Attempts to clone whole pCR1 in Escherichia coli were unsuccessful but two of its fragments (750 and 650 bp) could be separately cloned in it. The 4.4-kb plasmid, pCR3, bears considerable restriction pattern similarity to a 4.4-kb plasmid belonging to the pBL1 group of cryptic plasmid of corynebacteria but has no sequence homology, suggesting that pCR3 represents a new member of the 4.4-kb group of corynebacterial plasmids.     

Clinal variation in carapace shape in the South American freshwater crab,Aegla uruguayana (Anomura: Aeglidae)

South America has been influenced by different geoclimatic events ever since its separation from Africa. The inland water fauna has evolved in response to the changing landscape. Currently, there are indications of variations in populations, occurring to different degrees that would indicate a clinal pattern in morphology. Among South America's fauna, the freshwater anomuran, Aegla, is an enigmatic group as a result of its endemicity and is composed of only one genus. Of all the species in this family, Aegla uruguayana has the broadest distribution. Its native habitats have been influenced by several marine transgressions during the Miocene–Quaternary Periods; thus, it is likely that their current distribution has been more recent. Its habitat spreads across a number of isolated basins and sub‐basins that display distinct degrees of isolation/connection, making clinal variation patterns in the morphology of this species possible. The present study aimed to evaluate the pattern of carapace shape variation in A. uruguayana and how it relates to the isolation and/or connection of populations from different basins and sub‐basins, allowing the determination of any extant clinal patterns. The specimens studied belong to 25 separate populations, representing all areas in which the species currently exists. A total of 523 crabs were analyzed. We identified 13 landmarks and four semi‐landmarks in the carapace. The aeglids were divided into seven size intervals to avoid an allometry effect. In each size category, shape relationships analyzed by principal component analysis suggest a geographical pattern corresponding to the distribution of the populations studied. An evaluation of covariation between body shape and geographical coordinates reveals a strong pattern and shows that population distribution had a significant effect on species morphology. Additionally, according to covariance analysis, the variation in shape was not associated with the environmental variables studied. We observed a clinal pattern throughout the species distribution, which could be attributed to genetic drift. It is possible that this process is being amplified by the geographical isolation of the basins, differences in environmental characteristics, and low dispersal ability. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 914–930.     

Sister-chromatid exchange and chromosome aberrations for 4 aliphatic epoxides in mice

Sister-chromatid exchange (SCE) and chromosome aberrations (CA) in bone marrow cells were analyzed after in vivo exposure in mice to 4 aliphatic epoxides, namely 1-naphthyl glycidyl ether (NGE), 1-naphthyl propylene oxide (NPO), 4-nitrophenyl glycidyl ether (NPGE) and trichloropropylene oxide (TCPO). These compounds were selected as being among the most mutagenic aliphatic epoxides in our previous structure-mutagenicity studies with the Ames test. There were significant dose-related increases in SCE and CA results for all 4 epoxides. The order of genotoxicity as established through SCE was NGE greater than NPO greater than NPGE approximately equal to TCPO greater than solvent control. It is of interest that Ames Salmonella results are consistent with in vivo genotoxicity for these compounds. However, only the plate test version of the Ames procedure is consistent with this order of in vivo genotoxicity and neither preincubation Ames testing results nor chemical alkylation rates would have predicted this order.     

NADPH production from NADP+ with a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans

Summary A convenient and efficient method of NADPH production from NADP⁺ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP⁺ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process.     

IL-1 secretion by macrophages. Enhancement of IL-1 secretion and processing by calcium ionophores

In the present study we have demonstrated that the murine IL-1 alpha precursor lacks a cleavable signal sequence and does not undergo cotranslational translocation across microsomal membranes in vitro. Culture supernatants of the murine macrophage cell line, P388D, or from normal peritoneal macrophages collected within 0.5 to 3 h after stimulation contained the 33,000 m.w. precursor as the predominant form of IL-1 alpha. Over an 18-h period, the level of low m.w. IL-1 alpha increased as the secreted precursor was processed by extracellular and/or cell surface-associated proteolytic enzymes. The calcium ionophores A23187 and ionomycin were found to dramatically enhance the release and processing of murine and human IL-1. The rapid release of IL-1 in response to a change in the intracellular level of calcium does not appear to be caused by release of a membrane-bound form of the protein, nor is there evidence that IL-1 is packaged and released from cytoskeletal associated secretory granules. In marked contrast, calcium ionophores do not induce secretion of IL-1 from a nonmacrophage cell line that synthesizes but does not normally secrete IL-1. Our results suggest that activated macrophages possess a novel processing independent, possibly calcium-dependent, mechanism that allows for the release of the precursor forms of IL-1 alpha and IL-1 beta.     

Identification of IL-1 receptors on human monocytes

The expression and functional analysis of IL-1 beta R on human monocytes were investigated. Binding of 125I-IL-1 to human monocytes was found to be specific and saturable. Scatchard plot analysis revealed a single class of receptors with a binding constant of 600 pM and a receptor density of approximately 100 binding sites per cell. At 37 degrees C 54% of the labeled ligand was internalized over 2 h of incubation. Addition of 0.2% sodium azide to the cells reduced ligand internalization to 9% of total bound. Cross-linking studies revealed that the IL-1R in human monocytes had a Mr of 80 kDa. The addition of IL-1 to monocytes caused changes in membrane Ag expression as assessed by flow cytometric analysis. The results of this study identify IL-1 receptors on monocytes and suggest that IL-1 may act as an effector molecule for monocytes by enhancing expression of Ag correlated with cell differentiation and immune function.     

Effect of stocking density on growth and survival of Clarias batrachus (Linn.) larvae and fry during hatchery rearing

Experiments were conducted to determine optimum stocking density for Clarias batrachus larvae and fry during hatchery rearing. The increase in stocking density decreased the total weight, specific growth rate (SGR) and percent weight gain of Clarias larvae during a 13‐day experiment. Survival rate was highest at a stocking density of 1000 m^?2 and lowest at 5000 m^?2. Stocking density did not influence the total biomass production of larvae. Clarias batrachus fry performance was studied during a 28‐day hatchery rearing experiment whereby fry stocked at a density of 100 m^?2 attained the highest total body weight (P < 0.05). The survival rate greatly declined to 59–61% by a density increase to 300 m^?2 and above. Stocking density influenced growth and survival of C. batrachus larvae and fry during hatchery rearing. The best performance was obtained when larvae were stocked at 2000 m^?2; survival was highest with C. batrachus fry stocked at 200 m^?2.