Social behavior in a captive chimpanzee (Pan troglodytes) group

A group of captive chimpanzees, consisting of one adult male and three mother/infant pairs, was systematically observed over a 15-month period. Over 200 hr of data were collected, using both sequential and time sampling techniques, and compared to the available data on wild chimps. Unlike many captive groups, most behavior patterns were remarkably similar, both qualitatively and quantitatively, to that of wild chimpanzees including: play, grooming, infant sexual development, tool use, food sharing, prosocial partner preferences, and aggressive displays.     

Islet cell and 64K autoantibodies are associated with plasma IgG in newly diagnosed insulin-dependent diabetic children

There is a high prevalence of islet cell antibodies (ICA) and autoantibodies detected against an islet cell protein of Mr 64,000 at the time of clinical diagnosis of insulin-dependent diabetes (IDDM). In view of the biphasic immune response after antigen presentation, the purpose of this study was to determine the presence of ICA and antibodies against the 64,000 islet antigen after separation of IgM from IgG to prevent interference between the two antibody classes. Plasma samples from 10 newly diagnosed IDDM children and 10 healthy controls were precipitated with polyethylene glycol (PEG), and the crude Ig was subjected to Sephacryl S-300 chromatography to separate IgM and IgG. ICA determined by indirect immunofluorescence on frozen sections of human pancreas showed reduced background immunofluorescence intensity in the purified fractions compared with crude plasma. The number of ICA-positive samples among the IDDM patients increased from 7/10 in plasma to 9/10 in the IgG fraction. There was an increase in the ICA titer in 6/9 of the positive samples. All purified IgM samples were ICA negative. Immunoprecipitation experiments by using Nonidet P-40 detergent lysates of [35S]methionine-labeled neonatal rat islets demonstrated that the 64,000 autoantibodies were in the IgG fraction. We found 7/10 IDDM samples to be positive, whereas all controls were negative. The background in the autoradiographic analysis was markedly reduced in the IgG fractions compared with immunoprecipitates with crude or PEG-purified plasma and the IgM fraction. ICA titers did not correlate to the ability of the IgG fraction to precipitate the 64,000 autoantigen. It is concluded that both the ICA and 64,000 autoantibodies are primarily of the IgG class at the time of clinical onset of IDDM, and that purification of IgG from human IDDM plasma facilitates the detection of the rat islet cell 64,000 antigen.     

Glycosylation of catalase inhibitor necessary for activity

A protein isolated from maize scutella which inhibits catalase in vitro has been shown to contain 12% carbohydrate in the form of galactose. This corresponds to four galactose molecules per inhibitor subunit. Removal of the carbohydrate with β-galactosidase or blockage with a galactose-specific lectin abolished activity of the inhibitor.     

Role of methyl groups in dynamics and evolution of biomolecules

Recent studies have discovered strong differences between the dynamics of nucleic acids (RNA and DNA) and proteins, especially at low hydration and low temperatures. This difference is caused primarily by dynamics of methyl groups that are abundant in proteins, but are absent or very rare in RNA and DNA. In this paper, we present a hypothesis regarding the role of methyl groups as intrinsic plasticizers in proteins and their evolutionary selection to facilitate protein dynamics and activity. We demonstrate the profound effect methyl groups have on protein dynamics relative to nucleic acid dynamics, and note the apparent correlation of methyl group content in protein classes and their need for molecular flexibility. Moreover, we note the fastest methyl groups of some enzymes appear around dynamical centers such as hinges or active sites. Methyl groups are also of tremendous importance from a hydrophobicity/folding/entropy perspective. These significant roles, however, complement our hypothesis rather than preclude the recognition of methyl groups in the dynamics and evolution of biomolecules.