Effectiveness of acoustic “prey”: Environmental enrichment for a captive African leopard (Panthera pardus)

In the course of developing active naturalistic exercise opportunities for zoo felines at moderate cost, a computer-controlled acoustic prey device was established. Changes in the behavior of a 16-year-old melanistic leopard (Sabrina) were studied as she learned to actively pursue bird sounds and obtained food treats as a function of the activity. By the twenty-ninth day she began to capture all 24 bird parts supplied on the feeder belt and continues to actively use the opportunity on a daily basis. General activity and apparent well-being have been enhanced, while stereotypic behaviors have decreased. © 1995 Wiley-Liss, Inc.     

Systemically Induced Resistance in Potato Cultivars with Different Degree of Resistance to Late Blight caused by Phytophthora infestans (Mont.) de Bary

Systemically induced resistance in potato plants (Solanum tuberosum L.) against late blight Phytophthora infestans was studied macroscopically on three potato cultivars with different degrees of resistance to late blight. The cultivars, were Bintje(2), Elin(3) and Matilda(4). Figures within brackets represent resistance to leaf late blight on a scale from 1 to 5, where 5 denotes the highest level of resistance. In vitro propagated cuttings were used in the experiments, which were, performed under controlled environmental conditions. Disease resistance was induced by a local pre-infection with P. infestans or with the nonpathogen P. cryptogea. Induced resistance was observed on all cultivars. The protection causedby, induced resistance tended to be most intense on cv. Matilda, with 50–60% reduction in lesion formation 4 days after challenge inoculation.     

The murine 3β-hydroxysteroid dehydrogenase multigene family: Structure, function and tissue-specific expression

The classical form of the enzyme 5-ene-3β-hydroxysteroid dehydrogenase/isomerase (3βHSD), expressed in adrenal glands and gonads, catalyzes the conversion of 5-ene-3β-hydroxysteroids to 4-ene-3-ketosteroids, an essential step in the biosynthesis of all active steroid hormones. To date, four distinct mouse 3βHSD cDNAs have been isolated and characterized. These cDNAs are expressed in a tissue-specific manner and encode proteins of two functional classes. Mouse 3βHSD I and III function as 3β-hydroxysteroid dehydrogenases and 5-en→4-en isomerases using NAD⁺ as a cofactor. The enzymatic function of 3βHSD II has not been completely characterized. Mouse 3βHSD IV functions only as a 3-ketosteroid reductase using NADPH as a cofactor. The predicted amino acid sequences of the four isoforms exhibit a high degree of identity. Forms II and III are 85 and 83% homologous to form I. Form IV is most distant from the other three with 77 and 73% sequence identity to I and III, respectively. 3βHSD I is expressed in the gonads and adrenal glands of the adult mouse. 3βHSD II and III are expressed in the kidney and liver with the expression of form II greater in kidney and form III greater in liver. Form IV is expressed exclusively in the kidney. Although the amino acid composition of forms I, III and IV predicts proteins of the same molecular weight, the proteins have different mobilities on SDS-polyacrylamide gel electrophoresis. This characteristic allows for differential identification of the expressed proteins. The four structural genes encoding the different isoforms are closely linked within a segment of mouse chromosome 3 that is conserved on human chromosome 1.     

An active-site carboxyl group in liquefying α-amylase: specific chemical modification

Bacillus amyloliquefaciens -amylase activity is pH-dependent and the plot log (Vmax/Km) versus pH implicated a carboxyl group of aspartic acid/glutamic acid at the active site. Chemical modification of -amylase with EDC confirmed this view. Further, analysis of inactivation kinetics showed that modification of a single carboxyl group led to complete loss of the enzymic activity.     

Growth,nitrogen fixation and relative efficiency of nitrogenase inAlnus incana grown in different cultivation systems

Summary Three cultivation systems were compared. In one system the alders were grown hydroponically. In the two other systems the alders were planted in gravel and either given water and nutrients at intervals or the nutrient solution was continuously supplied. Alders continuously supplied with nutrients and water showed a significantly more rapid growth, higher biomass production and higher nitrogen content than did alders given nutrients and water at intervals or alders hydroponically grown. Alders continuously supplied with water and nutrients had a constant RE (relative efficiency of nitrogenase) of about 0.80 throughout the experimental period while alders supplied with water and nutrients at intervals showed a slight decrease in RE at the end of the experimental period. No strict relationship was found between RE and nitrogen content or between RE and plant productivity.     

Analysis of the HLA-ABC linkage disequilibrium: Decreasing strength of gametic association with increasing map distance

Summary 1242 HLA-ABC haplotypes of the North German population (Hamburg) as deduced by family analyses are described. They are in perfect agreement with recently published data by Mayr (1977) from Austria (Vienna) in all parameters tested: frequency of the single HLA-alleles, haplotype distribution and linkage disequilibrium values. Gametic association studies revealed that 69.4% of the B and C genes (map distance 0.2 cM) 36.9% of the A and C genes (0.6 cM), but only 23.2% of the A and B genes (0.8 cM) were significantly more often combined than expected due to their frequencies. From these findings it seems likely that the linkage disequilibrium within the MHC is rather due to a short evolutionary period than to selective forces. Some observations as to the most common European haplotype A1,B8 are discussed.     

Dihydroisocoumarins and phthalide from wood samples infested by fungi

Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3R)-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS.     

Purification and characterization of an (Na++K+)-ATPase proteolipid labeled with a photoaffinity derivative of ouabain

Highly purified lamb kidney (Na⁺+K⁺)-ATPase was photoaffinity labeled with the tritiated 2-nitro-5-azidobenzoyl derivative of ouabain (NAB-ouabain). The labeled (Na⁺+K⁺)-ATPase was mixed with unlabeled carrier enzyme. Two proteolipid (γ1 and γ2) fractions were then isolated by chromatography on columns of Sepharose CL-6B and Sephadex LH-60. The two fractions were interchangeable when rechromatographed on the LH-60 column, suggesting that γ1 is an aggregated form of γ2. The total yield was 0.8–1.5 mol of γ component per mol of catalytic subunit recovered. This indicates that the γ component is present in stoichiometric amounts in the (Na⁺+K⁺)-ATPase. The proteolipids that were labeled with NAB-ouabain copurified with the unlabeled proteolipids.     

Transforming growth factor-β inhibition of interleukin-1 activity involves down-regulation of interleukin-1 receptors on chondrocytes

Interleukin-1 (IL-1) plays an important role in cartilage destruction associated with inflammatory and degenerative arthritis because of its ability to induce matrix degrading enzymes. Previously, we have shown that the IL-1-induced chondrocyte protease activity was inhibited by transforming growth factor-β (TGF-β). In this paper, we show that TGF-β inhibits the IL-1-induced synthesis of collagenase and stromelysin by reducing the steady-state mRNA levels in rabbit articular chondrocytes. We further demonstrate that TGF-β-treated chondrocytes show reduced ¹²⁵I-IL-1 binding that returns to a normal level when TGF-β is removed from the culture medium. The inhibitory effect of TGF-β is observed for both naturally occurring as well as fibroblast growth factor (FGF)-inducible binding sites (receptors). Scatchard analysis of receptor—ligand interactions demonstrate that the reduced binding is due to a reduction in the number of receptors for IL-1 and is not due to changes in affinity. Affinity cross-linking studies suggest that control chondrocytes contain two major cross-linked bands of M_r =116 and 80 kDa and a minor band of M_r =100 kDa. FGF-treated cells show enhanced levels of all the bands, plus an additional 200-kDa band. TGF-β treatment of chondrocytes results in the reduction of all of these bands in both control as well as FGF-induced cells. These observations suggest that the ability of TGF-β to down-regulate the IL-1 receptor may be a mechanism by which it exerts its effects in antagonizing the IL-1 activity on chondrocytes.