Transport of cyclitols by a proton symport in Klebsiella aerogenes.

The respiration and the ATP content of Klebsiella aerogenes in the presence of various inhibitors were compared to the transport of scyllo-inositol. The ATPase was found to be inhibited by dicyclohexyl carbodiimide. The transport has been tested in anaerobiosis and aerobiosis. From the results obtained it is concluded that either ATP or respiration can sustain the transport activity in independent manner. 2. The energy derived from the respiratory chain reactions or the ATP hydrolysis results in electrogenic extrusion of protons. The electrochemical potential created drives the accumulation of scyllo-inositol, as shown by an increase of pH of the medium on addition of the substrate to cells in anaerobiosis. With non-induced cells no change in pH occurs, which demonstrates that proton flow is really linked to the transport. No H+/Na+ or K+ exchange is observed and the proton conductor carbonylcyanide m-chlorophenylhydrazone abolishes the pH shift caused by substrate addition. The stoichiometry of the symport H+/cyclitol is 1 and the half-maximum value of the pH variation as a function of the amount of scyllo-inositol added corresponds to a concentration of scyllo-inositol very close to the KT of influx.     

Control of proteoglycan synthesis. Studies on the activation of synthesis observed during culture of articular cartilages.

When slices of adult rabbit articular cartilage were incubated in culture medium, the rate of incorporation of [35S]sulphate or [3H]acetate into glycosaminoglycans increased 4-8 fold during the first 5 days of incubation. Similar changes in biosynthetic activity were observed during culture of adult bovine cartilage. The activation of synthesis was not serum-dependent, but appeared to be a result of the depletion of tissue proteoglycan that occurs under these incubation conditions [Sandy, Brown & Lowther (1978) Biochim. Biophys. Acta 543, 536--544]. Thus, although complete activation was observed in serum-free medium, it was not observed if the cartilage was cultured inside dialysis tubing or in medium containing added proteoglycan subunit. The average molecular size of the proteoglycans synthesized by activated tissue was slightly larger than normal, as determined by chromatography on Sepharose CL-2B, and the average molecular size of the glycosaminoglycans synthesized by activated tissue was markedly increased over the normal. The increase in chain size was accompanied by an increase in the proportion of the chains degraded by chondroitinase ABC; these results are consistent with the preferential synthesis by activated chondrocytes of chondroitin sulphate-rich proteoglycans. The increase in glycosaminoglycan chain size was observed whether the chains were formed on endogenous core protein or on exogenous benzyl-beta-D-zyloside. An approximate 4-fold activation in culture of glycosaminoglycan synthesis on protein core was accompanied by a 1.54-fold increase in the rate of incorporation of [3H]serine into the chondroitin sulphate-linkage region of the proteoglycans. A 2.8-fold activation in culture of glycosaminoglycan synthesis on benzyl-beta-D-zyloside was accompanied by a 1.7-fold increase in the rate of incorporation of [3H]benzyl-beta-D-zyloside into glycosaminoglycans. The activation of glycosaminoglycan synthesis was, however, accompanied by no detectable change in the activity of xylosyltransferase (EC 2.4.2.26) in cell-free extracts. These results are discussed in relation to current ideas on the control of proteoglycan synthesis in cartilage.     

Daytime births in captive patas monkeys

Daytime births in two patas colonies were the rule rather than the exception.     

Analysis of the catabolism of aggrecan in cartilage explants by quantitation of peptides from the three globular domains

A method has been developed for the production, isolation, and quantitation of 15 marker peptides from the three globular domains (G1, G2, and G3) and the interglobular domain of bovine aggrecan (aggregating cartilage proteoglycan). Three of the peptides are from G1, two are from the interglobular domain, four are from G2, and six are from G3. The method involves separation of tryptic peptides by sequential anion-exchange, cation-exchange, and reversed-phase high performance liquid chromatography and quantitation by absorbance at 220 nm. The values obtained (peak area per microgram of core protein) were a function of the molar yield and also the size and aromatic residue content of individual peptides. This procedure has been applied to aggrecan purified from fresh calf articular cartilage and to aggrecan isolated from the medium and tissue compartments of cartilage explant cultures, maintained in basal medium for 15 days without and with interleukin-1 alpha. These analyses indicate that aggrecan which is released into explant medium has a reduced content of the G1 domain, but has a normal content of the G2 domain, the COOH-terminal region of the interglobular domain, and also the G3 domain. On the other hand, aggrecan which is retained by the cartilage during 15 days of culture has a normal content of G1, interglobular domain, and G2 domains, but, in the presence of interleukin-1 alpha, it has a reduced content of the G3 domain. The percentage of medium molecules which retained the G1 domain was higher in control cultures (about 35%) than in interleukin cultures (about 20%), and this was consistent with the relative aggregability of these samples. Taken together these results suggest that catabolism of aggrecan in articular cartilage involves a specific proteolysis of the core protein at a site which is within the interglobular domain and NH2-terminal to the sequence LPGG. This process occurs in control cultures but is accelerated by the addition of interleukin-1 alpha. Degraded molecules which lack the G1 domain are released preferentially into the medium; however, these molecules carry both the G2 and G3 domains, indicating that these domains do not confer strong matrix binding properties on aggrecan. The method described here for the isolation of peptides from bovine aggrecan should have wide application to structural and biosynthetic studies on this molecule in species such as human and rat, since many of the marker peptides are from highly conserved regions of the aggrecan core protein.     

Human eosinophil, but not neutrophil, adherence to IL-1-stimulated human umbilical vascular endothelial cells is alpha 4 beta 1 (very late antigen-4) dependent.

Eosinophils, through their ability to generate an array of potent mediators, are thought to be the major effector cells in a number of conditions, including parasitic infection, asthma, and other allergic diseases. The mechanism(s) by which eosinophils, as opposed to neutrophils, accumulate at inflammatory sites is unknown. One possible mechanism would be an eosinophil-specific pathway of adhesion to vascular endothelium. In this study we have demonstrated that human eosinophils, but not neutrophils, constitutively express alpha 4 beta 1 (CD49d/CD29). Expression was not increased on low density eosinophils or normal density cells stimulated with platelet-activating factor. Eosinophils, but not neutrophils, specifically adhered to COS cells transfected with vascular adhesion molecule-1 in a alpha 4 beta 1-dependent manner. Eosinophil, but not neutrophil, adhesion to IL-1 stimulated human umbilical vascular endothelial cells was significantly inhibited by alpha 4 beta 1 mAb at both 5 h (p less than 0.05) and 20 h (p less than 0.001). Inhibition of both resting and platelet-activating factor-(10(-7) M) stimulated eosinophil adhesion was observed. We conclude that the alpha 4 beta 1/vascular adhesion molecule-1 adhesion pathway may be involved in specific eosinophil, as opposed to neutrophil, migration into sites of eosinophilic inflammation.     

Identification of a stromelysin cleavage site within the interglobular domain of human aggrecan. Evidence for proteolysis at this site in vivo in human articular cartilage.

Products generated by the digestion of human aggrecan with recombinant human stromelysin have been purified and analyzed by N-terminal sequencing and C-terminal peptide isolation. N-terminal analysis of chondroitin sulfate-bearing fragments revealed a clearly identifiable sequence initiating at residue Phe342 of human aggrecan, providing evidence for a cleavage site at the Asn341-Phe342 bond located within the interglobular domain. This cleavage site, which separates the G1 domain from the remainder of the molecule, was confirmed by isolation from the liberated G1 domain of a C-terminal tryptic peptide with the sequence YDAICYTGEDFVDIPEN (in which the C-terminal residue is Asn341). This peptide was also isolated from tryptic digests of hyaluronan-binding proteins (A1D4 samples) prepared by CsCl gradient centrifugation of extracts of mature human articular cartilages. Since these A1D4 samples contain G1 domain which accumulates as a result of aggrecan catabolism in vivo, these results clearly indicate that stromelysin cleaves the Asn341-Phe342 bond of human aggrecan in situ.     

Odoriferous Therapy: A Review Identifying Essential Oils against Pathogens of the Respiratory Tract

This review explores the body of scientific information available on the antimicrobial properties of essential oils against pathogens responsible for respiratory infections and critically compares this to what is recommended in the Layman's aroma‐therapeutic literature. Essential oils are predominantly indicated for the treatment of respiratory infections caused by bacteria or viruses (total 79.0 %), the efficacy of which has not been confirmed through clinical trials. When used in combination, they are often blended for presumed holistic synergistic effects. Of the essential oils recommended, all show some degree of antioxidant activity, 50.0 % demonstrate anti‐inflammatory effects and 83.3 % of the essential oils showed antihistaminic activity. Of the essential oils reviewed, 43.8 % are considered non‐toxic while the remaining essential oils are considered slightly to moderately toxic (43.7 %) or the toxicity is unknown (12.5 %). Recommendations are made for further research into essential oil combinations.