Immunological comparison of glyoxalase I from yeast and mammals and quantitative determination of the enzyme in human tissues by radioimmunoassay

Antibodies to glyoxalase I from yeast, rat liver, porcine erythrocytes and human erythrocytes were raised in rabbits. Gel precipitation and immunotitration experiments demonstrated that the mammalian enzymes were immunologically related, but distinct from the yeast enzyme. Fab fragments of the antibodies to human glyoxalase I did not inhibit the catalytic activity, indicating that the antigen binding sites were not directed towards the active site of the enzyme. A radioimmunoassay for glyoxalase I was developed. Quantitative analysis of human adult as well as fetal organs demonstrated that glyoxalase I was present in a concentration of approximately 0.2 micrograms/mg protein in most human tissues.     

Recolonization following past persecution questions the importance of persistent snow cover as a range limiting factor for wolverines

Globally, climate is changing rapidly, which causes shifts in many species' distributions, stressing the need to understand their response to changing environmental conditions to inform conservation and management. Northern latitudes are expected to experience strongest changes in climate, with milder winters and decreasing snow cover. The wolverine (Gulo gulo) is a circumpolar, threatened carnivore distributed in northern tundra, boreal, and subboreal habitats. Previous studies have suggested that wolverine distribution and reproduction are constrained by a strong association with persistent spring snow cover. We assess this hypothesis by relating spatial distribution of 1589 reproductive events, a fitness-related proxy for female reproduction and survival, to snow cover over two decades. Wolverine distribution has increased and number of reproductive events increased 20 times in areas lacking spring snow cover during our study period, despite low monitoring effort where snow is sparse. Thus, the relationship between reproductive events and persistent spring snow cover weakened during this period. These findings show that wolverine reproductive success and hence distribution are less dependent on spring snow cover than expected. This has important implications for projections of future habitat availability, and thus distribution, of this threatened species. Our study also illustrates how past persecution, or other factors, that have restricted species distribution to remote areas can mask actual effects of environmental parameters, whose importance reveals when populations expand beyond previously restricted ranges. Overwhelming evidence shows that climate change is affecting many species and ecological processes, but forecasting potential consequences on a given species requires longitudinal data to revisit hypotheses and reassess the direction and magnitude of climate effects with new data. This is especially important for conservation-oriented management of species inhabiting dynamic systems where environmental factors and human activities interact, a common scenario for many species in different ecosystems around the globe.     

Enantioselective lipase-catalyzed ester hydrolysis: Effects on rates and enantioselectivity from a variation of the ester structure

In order to make a preliminary study of substituent effects on the rate and enantioselectivity obtained in esterolytic reactions catalyzed by a lipase from Candida rugosa, a series of racemic esters, derived from some α-alkyl and α-halo phenylacetic acids, were prepared. The reactions were studied at pH 6.0 and 50°C under which conditions uncatalyzed hydrolysis was relatively slow. Reaction samples were studied at different points of time by means of analytical chiral reversed-phase liquid chromatography, which permitted the simultaneous determination of product enantiomeric excess and of the degree of total ester hydrolysis. These data were then used to calculate initial rates as well as enantioselectivity. An increase of the steric bulk of the α-substituent was found to highly decrease the rate of the reaction. On the other hand, rates were higher for the p-nitrophenyl esters than for the corresponding 2-chloroethyl esters. Consistently, the enantioselectivity was found to be higher for the latter type of ester. The esters of the α-halo (bromo and chloro) phenylacetic acids gave mandelic acid as the final product. This was caused by a rapid solvolysis of the α-halo phenylacetic acid initially formed. © 1993 Wiley-Liss, Inc.     

THE RELATIONSHIP BETWEEN A FLOWER GALL MIDGE PSEUDAS-PHONDYLIA SP. (DIPTERA: CECIDOMYIIDAE) AND ITS HOST PLANT ACTINIDIA VALVATA*

Abstract Kiwifruit plants, Actinidia sp., are native to subtropical China. The flower-bud gall of A. valvata, which is induced by an undescribed gall midge in the genus Pseud as phond ylia, is valued by the pharmaceutical industry. When studying the biology of the Actinid ia/Pseud as phond ylia interaction in Central-south China we found evidence suggesting that under certain circumstances the gall insect modifies the reproductive mode of the dioecious host plant. Surveys and field experiments in the National Hupingshan Natural Reserve showed a high frequency of galled trees. The density of galled trees varied among valleys and among trees within the valleys. In two valleys, 92% and 75%, respectively, of all trees were attacked, while in a third valley no trees were attacked. When infested, staminate tree only produced galls, whereas pistillate plants produced normal fruits as well as galls. Gall shape differed between male and female trees. Trees with galls tended to produce more fruits than treea without galls. We speculate that this is one of a few documented examples of an insect that induces androdioecy in an otherwise functionally dioecious plant.     

Chromatographic resolution of some cyclic sulfoximides derived from prochiral and chiral sulfoxides

Three endocyclic sulfoximides of the 1-aryl- and 1-alkyl-3-oxo-benzo[d]-isothia (IV)-azole 1-oxide type (1-substituent = 2′-carboxyphenyl, 2′-carbethoxyphenyl, and octyl, respectively) were found to be well resolved on a chiral phase derived from bovine serum albumin (BSA). Selectivities (α) of 1.74, 1.12, and 1.44, respectively, were obtained. The retention behaviour of 1-octyl-3-oxo-benzo[d]isothia(IV)-azole 1-oxide was further investigated in some detail as a function of the mobile phase composition and the elution order was established from optically active material obtained from the enantiopure sulfoxide precursor. An enantiomeric excess of 85.4% was obtained in the cyclocondensation reaction of the octyl-substituted sulfoxide precursor with hydrazoic acid to the corresponding endocyclic sulfoximide. © 1995 Wiley-Liss, Inc.     

Long-term parenteral nutrition

Nineteen patients (11 women and eight men) aged 20-68 received long-term parenteral nutrition, mostly at home, for six to 63 months (mean 19 months). Indications for LTPN were extensive, active Crohn''s disease in three patients, intestinocutaneous fistulas in three, and short-bowel syndrome in the remaining 13 patients. Subclavian or intra-atrial (Broviac) catheters were most commonly used, for which the average life was four and seven months respectively. Complications of long-term parenteral nutrition included pneumothorax in four out of 48 subclavian vein punctures. Catheter-induced thrombosis of central veins was shown by phlebography 17 times in nine patients, and eight episodes of total occlusion occurred. Two of these patients had pulmonary infarction. Nineteen episodes of catheter sepsis occurred in 11 patients, but only one was fatal. Complications related to intestinal disease included intra-abdominal abscesses and intestinal fistulas, and disturbances of liver function. Five patients died, though in only two was death related to long-term parenteral nutrition. One of these patients died from catheter sepsis, the other had subdural haematoma possibly caused by anticoagulant treatment. Eight of the 14 surviving patients still needed parenteral nutrition. All received a disability pension, but six had an acceptable quality of life with almost normal social activities.Despite problems such as difficulties in maintaining standardised infusion programmes, it was concluded that long-term parenteral nutrition at home is practicable and consistent with an acceptable quality of life.     

Regeneration of cleared Acacia zanzibarica bushland in Kenya

Abstract. Woody biomass production in natural forests of arid and semi-arid regions is low. The fuelwood demand of settlements often exceeds the sustained yield and regeneration capacity of natural forests, which results in deforestation. Regeneration and woody biomass development was studied in cleared Acacia zanzibarica bushland in Bura, eastern Kenya. The area was cleared in 1982 and studied in 1988. The site had been colonized primarily by Acacia zanzibarica and A. reficiens. Mean density was 1333 trees/ha, mean total woody biomass (dry weight) 1954 kg/ha, equal to 2.53 m³/ha. Mean annual increment was 293 kg/ha, or 0.3 8m³/ha. Expressed as rain use efficiency, the natural dry matter productivity of the woody component equals 0.83 kg ha^-1 yr^-1 mm^-1. The regeneration potential and some management implications are discussed.