Immobilization of tyrosinase within polyacrylamide gels

The enzyme tyrosinase (E.G. 1.14.18.1) has been immobilized in a polyacrylamide gel and intermittently assayed for enzyme activity over a period of 19 days using phenol as the substrate. The results of these studies indicate that the immobilized enzyme could be incorporated into a system to detect phenol and related compounds that are found in industrial effluents and as surface water contaminants.     

Relation of ice formation to ultrastructural cryoinjury and cryoprotection of rough endoplasmic reticulum

Ultrastructural observations on the frozen state of pancreatic acinar cells were correlated with results of parallel studies before freezing and after thawing, as to cryoinjury and cryoprotection.Data support an hypothesis of freezing injury based upon intracellular ice and solution effects during rapid and slow freezing, respectively. The basis for superiority of extracellular over intracellular glycerol in cryoprotection was demonstrated in terms of these factors.Evidence is offered to explain the ultrastructural cryoinjury and cryoprotection of rough endoplasmic reticulum (RER) seen after thawing, relative to the combined effects of freezing rate and glycerol. Slow freezing, in combination with the presence of extracellular glycerol, provided sufficient dehydration to almost completely suppress intracellular ice formation, yielding minimal ultrastructural alteration of RER. Greatest cryoinjury, expressed as extensive conversion of RER into sphere-like vesicles, was induced by the extensive intracellular ice formation which accompanied rapid freezing. A mechanism is suggested to explain physical damage of RER by intracellular ice.     

我国北方异色瓢虫越冬集群的调查研究:越冬场所的调查初报

在毛主席革命路线指引下,我国农林害虫的生物防治得到了迅速发展。为了在本世纪内,全面实现农业、工业、国防和科学技术现代化,在植物保护工作上,我们要积极贯彻“预防为主,综合防治”的方针,采取综合防治消灭害虫。“以虫治虫”是其中的重要措施。研究益虫越冬集群的规律,扩大益虫来源,给利用天敌提供丰富的物质基础,为此开展本题的调查研究。     

Primary structure of streptococcal proteinase. III. Isolation of cyanogen bromide peptides: complete covalent structure of the polypeptide chain.

The following sequence has been derived for streptococcal proteinase. (See article). The sequence permits the assignment of the single cysteine residue essential for catalytic action at position 47 from the NH2 terminus of the protein. The tryptophan residue at the binding site of the enzyme is at position 214. A histidine residue at position 195 has been assigned as the catalytically important entity in the molecule. Streptococcal proteinase and papain, an enzyme with similar properties, are compared with respect to structure and function.     

Carbohydrate components of the glycopeptides of ovine lutropin

The three tryptic glycopeptides from ovine lutropin, in which two were from the α-subunit (α-56 and α-82 glycopeptides) and one from the β-subunit (β-13 glycopeptide), have been isolated and their carbohydrate compositions analyzed. The results indicate that the α-56 glycopeptide has the highest amount of carbohydrate, whereas the β-13 glycopeptide has the least. In general, each of the glycopeptides has similar distribution of various sugars, i.e. high in mannose and glucosamine and low in fucose, sialic acid, galactose and galactosamine. Within the limit of experimental error, the sum of their carbohydrate composition is in agreement with the published data on the intact hormone or separated subunits.     

Preparation and chemical characterization of the three chains of the major hemoglobin of the sea snake, Pelamis platurus.

One of the 2 main hemoglobins of the sea snake Pelamis platurus, (the Yellow-bellied sea snake) comprising about 70% of the total hemoglobin, was separated by DEAE-Sephadex column chromatography. From results of gel filtration and iron content determination, both intact sea snake hemoglobin, and the isolated major hemoglobin, were concluded to be composed of 4 subunits with a molecular weight of 66,000-67,000 daltons. Separation of the chains of globin of the major hemoglobin by CM 52 column chromatography gave 3 peaks, named, chains a, b, and c. The approximate molecular weights of chains a, b, and c were deduced by SDS gel electrophoresis to be 14,000, 16,000, and 20,000 daltons, respectively. The peptide maps and amino acid compositions of the three chains were distinctly different. N-Terminal and C-terminal amino acid sequence studies reveal that chains a, b, and c represented the alpha-chain, beta-chain, and beta'-chain differing from the normal beta-chain in having a C-terminal sequence of -Arg-Leu-His-Tyr. From the peak areas of the 3 chains obtained by CM 52 column chromatography, and the peak sizes of the 3 bands separated by SDS gel electrophoresis, it was concluded that the sea snake hemoglobin is composed of a hybrid tetramer, alpha2betabeta'.     

Alkaline ribonuclease and ribonuclease inhibitor in mammary gland during the lactation cycle and in the R3230AC mammary tumour.

Alkaline RNAase (ribonuclease) and RNAase inhibitor were assayed to determine the potential role of the degradative process in regulating the amount of RNA in the mammary gland and mammary tumour. Very little free alkaline RNAase activity was found in the cytosol fraction of the mammary gland of virgin, pregnant, lactating or involuting Fischer rats. However, addition of p-chloromercuribenzoate to the assay medium revealed latent RNAase which, when expressed on a DNA basis, decreased during pregnancy and lactation. The cytosol latent RNAase is stable in 0.125 M-H2SO4. The non-cytosol RNAase activity also decreased during pregnancy and lactation. Addition of Triton X-100 produced slightly higher activity at all stages tested. The inhibitor activity in rat mammary gland was very low before pregnancy, increased gradually during pregnancy and more dramatically at parturition, continued to increase throughout lactation and returned to resting-gland values by the sixth day of involution. The increase during pregnancy may be due to the increased cellularity of the gland, whereas the gain during lactation was more than could be accounted for by increases in cell number. The R3230AC transplantable mammary tumour resembles the normal gland in early lactation with respect to both its cytosol and non-cytosol alkaline RNAase activities and its moderately high content of RNAase inhibitor. The relatively high inhibitor and low RNAase activities in both the gland of the lactating rat and in the tumour are of potential significance in maintaining high amounts of RNA and increased rates of protein synthesis in these tissues.