Human endothelin converting enzyme-2 (ECE2): characterization of mRNA species and chromosomal localization.

Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively.     

A rapid colorimetric assay for heparinase activity.

A rapid, sensitive, assay for enzymes that degrade heparin is described. The procedure is based on the interference of heparin with color development during the interaction of protein with the dye Coomassie brilliant blue. The loss of this property when the glycosaminoglycan is degraded by heparinase can be used to quantify activity of the enzyme in pure form, or in complex biological samples such as tissue homogenates or serum. The assay is also suitable for studying dependence of heparinase activity under conditions such as varying pH and temperature.     

Halophytes – A resource for the future

Wetlands Ecology and Management -     

Significance of mirex-caused hypoglycemia and hyperlipidemia in rats

Treatment of rats with mirex (40 ppm in diet) caused hypoglycemia, liver enlargement, and inhibition of adrenal corticosteroid-synthesizing enzyme activity. At toxic dosages (20,000 ppm mirex in diet, which has a lethal toxicity-50 [LT-50] of ten days) poisoned female rats showed severe hypoglycemia, fatty liver, adrenal hyperplasia, hypophagia, lipid mobilization, and body weight (bw) loss. A 50 μg/kg intraperitoneal (IP) dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in male rats caused similar effects two days posttreatment. Hypoglycemia could be overcome by prednisone (which also inhibited adrenocorticoid-synthesizing enzyme activities) but not by streptozotocin treatment, indicating that hypoglycemia may be related to glucocorticoid deficiency resulting from inhibition of their synthesis and not by direct effects on pancreatic β-cells. Glucocorticoid deficiency could also cause increased release of adrenocorticoid hormone (ACTH), which may enhance fat mobilization caused by hypophagia.     

Differential and analytical subfractionation of rat liver components internalizing insulin and prolactin

Receptor-mediated endocytosis of 125I-insulin and 125I-prolactin into liver parenchymal cells has been studied by quantitative subcellular fractionation. Differential centrifugation yielded three particulate fractions, N (nuclear), ML (large granule), and P (microsomes), and a final supernatant (S). Quantitative differences in the extent and rates of accumulation of 125I-insulin and 125I-prolactin into the fractions were observed. The acidotropic agent chloroquine and the microtubule disrupting agent colchicine were administered separately to rats. The agents increased significantly the T 1/2 of hormone clearance from the liver and augmented the accumulation of both ligands in the low-speed ML fraction. However, differences in the rates of accumulation of insulin and prolactin into all cell fractions were still maintained. Analytical centrifugation of each of the particulate fractions was carried out in order to determine if different endocytic components were specific to insulin or prolactin internalization. This was not the case. An "early" endosomal component of density 1.11 was identified in microsomes. A "late" endosome of density 1.10 was identified in the large granule (ML) fraction. Both endosomal components appeared to accumulate insulin and prolactin but at different rates. Marker enzyme analysis identified the presumed plasma membrane component in microsomes (density approximately 1.155). This component showed a significant difference in the rate of loss of 125I-insulin (T 1/2 approximately 4.1 min) as compared to that of 125I-prolactin (T 1/2 approximately 12.7 min). A further difference in the handling of the ligands was observed in early endosomes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Limnology and plankton periodicity of Jos Plateau water reservoir,Nigeria, West Africa

Limnological data (Dec. 1980–Jan. 1982) on the plankton and water chemistry of Lamingo Dam, located within the Jos biotite granite area of the Plateau State (Nigeria) are presented. The water-body falls in Beadle's (1981) category I of African lakes (conductivity < 40 µS cm^–1). Alkalinity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3914!\[\bar x\] = 0.3 meq l^–1), principally composed of bicarbonates, dominated the anions % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaK4waiaajI% eacaqIdbGaaK4tamaaxababaGaeyOeI0caleaacaaIZaaabeaakiaa% b6dacaqIdbGaaKiBaiaaj2cacaqG+aGaaK4uaiaaj+eadaqhaaWcba% GaaKinaaqaaiaajkdacaqITaaaaOGaaKyxaaaa!4657!\[\user1{[HCO}\mathop -\limits_3 {\text{ > }}\user1{Cl - }{\text{ > }}\user1{SO}_\user1{4}^{\user1{2 - }} \user1{]}\]The plankton were characterized by a moderate standing crop of phytoplankton, and zooplankton were, generally, very limited in species and abundance. The order of dominance for the categories of phyto and zooplankton was: [Bacillariophyceae > Chlorophyceae > Dinophyceae] and [Rotifera > Crustacea] respectively. A diel cycle was characterized by nocturnal upward migration of the zooplankton, and the reverse behaviour in the phytoplankton.Interrelations between the biotic assemblages of plankters and various physical and chemical variables are discussed.     

Influence of the presence of Zymomonas anaerobia on the conversion of cellobiose, glucose, and xylose to ethanol by Clostridium saccharolyticum

To convert sugar mixtures containing cellobiose, glucose, and xylose to ethanol in a single step, the possibility of using a coculture consisting of Clostridium saccharolyticum and Zymomonas anaerobia was studied. In monoculture, C. saccharolyticum utilized all three sugars; however, it preferentially utilized glucose and produced acetic acid in addition to ethanol. The formation of acetic acid from the metabolism of glucose inhibited the growth of C. saccharolyticum and, consequently, the utilization of cellobiose and xylose. In monoculture, Z. anaerobia utilized glucose at a rate of 50 g/L day, but it did not ferment cellobiose or xylose. In coculture, Z. anaerobia converted most of the glucose to ethanol during the lag phase of growth of C. saccharolyticum, which then converted cellobiose and xylose to ethanol. The use of this coculture increased both the rate and the efficiency of the conversion of these three sugars to ethanol, and produced relatively small amounts of acetic acid.