Systematics within Gyps vultures: a clade at risk

Background  

Populations of the Oriental White-backed Vulture (Gyps bengalensis) have declined by over 95% within the past decade. This decline is largely due to incidental consumption of the non-steroidal anti-inflammatory veterinary pharmaceutical diclofenac, commonly used to treat domestic livestock. The conservation status of other Gyps vultures in southern Asia is also of immediate concern, given the lack of knowledge regarding status of their populations and the continuing existence of taxonomic uncertainties. In this study, we assess phylogenetic relationships for all recognized species and the majority of subspecies within the genus Gyps. The continuing veterinary use of diclofenac is an unknown but potential risk to related species with similar feeding habits to Gyps bengalensis. Therefore, an accurate assessment of the phylogenetic relationships among Gyps vultures should aid in their conservation by clarifying taxonomic uncertainties, and enabling inference of their respective relatedness to susceptible G. bengalensis.     

Mediator structure and conformation change

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Rapid in Vivo Acylation of Acyl Carrier Protein with Exogenous Fatty Acids in Spirodela oligorrhiza

Posttranslational acylation of several chloroplast proteins with palmitic acid was recently demonstrated in Spirodela oligorrhiza (AK Mattoo, M Edelman [1987] Proc Natl Acad Sci USA 84: 1497-1501). We have now identified an in vivo acylated, soluble protein having an apparent M_r of 10 kilodaltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as an acylated form of acyl carrier protein (ACP). This 10-kilodalton protein is present in low abundance, and its acylation is light-stimulated. Turnover of the acyl moiety but not the apo-protein is rapid in the light. The acylated 10-kilodalton protein coelectrophoreses with in vitro synthesized palmitoyl-acyl carrier protein and is immunoprecipitated from soluble extracts with an antibody raised against spinach ACP. Cerulenin, an inhibitor of β-ketoacyl-ACP synthetase, inhibited in vivo acylation of Spirodela ACP. Cell-free extracts of Spirodela plants were able to catalyze the transfer of palmitate from palmitoyl-CoA to ACP, suggesting the existence in higher plants of a pathway for acylation of ACP that involves transacylation from acyl-CoA.     

Translational modification of an 18 kilodalton polypeptide by spermidine in rice cell suspension cultures

When rice (Oryza sativa) cell suspension cultures are grown in the presence of [terminal methylenes-³H]spermidine, label is incorporated in a single polypeptide with a molecular mass of 18 kilodaltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Preincubation of cell cultures with polyamine biosynthesis inhibitors difluoromethylarginine and difluoromethylornithine, resulted in increased incorporation of the label into the 18 kilodalton polypeptide. In cells in which protein synthesis was arrested by cycloheximide, no label was detected in the 18 kilodalton polypeptide, suggesting a requirement for de novo protein synthesis.     

Phosphoenolpyruvate-dependent protein kinase activity in rat skeletal muscle

Phosphoenolpyruvate-dependent protein kinase activity has been demonstrated in the soluble fraction of rat skeletal muscle. The reaction was not due to the formation of ATP in the incubation mixture. Cyclic AMP, calcium, ATP and a number of phosphate acceptor proteins did not stimulate the reaction. One 32P-labelled protein (Mr 25000) was observed on SDS gels. The phosphorylated protein contained acid stable phosphoserine as a major phosphorylated amino acid. The phosphorylation reaction in crude extracts was not directly proportional to the amount of protein, but typical of a two-component system; i.e., kinase and substrate. The chromatography of soluble proteins on Ultrogel AcA44 separated the phosphate acceptor protein(s) from the phosphoenolpyruvate-dependent protein kinase activity.     

Biochemical Aspects of Parasitism by the Angiosperm Parasites: Host-parasite Interrelationship in Phosphatase Activity

Infection by Cuscuta and Orobanche causes significant losses in dry solids and protein content in host plant or plant part. Changes occur in phosphatase activity towards fructose-1,6-diphosphate at alkaline pH and β-glycerophosphate at acid pH, expressed per mg protein or g fresh tissue. The leaves of all hosts infected by Orobanche show an increase in the alkaline fructosediphosphatase activity, whereas as far as the infection by Cuscuta is concerned the general response is a decrease in the enzyme in the shoots. The alterations in the phosphatase activity towards β-glycerophosphate at acid pH in the shoots are not consistent. However, there is a marked increase in the acid phosphatase activity against β-glycerophosphatase in the roots of the infected hosts. The significance of these findings has been discussed in the light of host-parasite interrelationship.