Preparation of microbe-free silage

Summary The construction and use of an apparatus for the preparation of microbe-free silage are described.The background of the investigations for which the apparatus is used is discussed.     

Silage studies. III. some characteristics of the silage microflora

Summary The microfloras in grass-legume silage of high and low quality have been investigated using small laboratory silos of special design.The development of the silage microfloras was followed by analyses at intervals by determination of the occurrence of the main groups bacteria and fungi as well as of lactic acid and proteolytic bacteria.Nearly all organisms occuring were isolated and the occurrence of the single types estimated.Physiological characteristics of the isolates such as acid production, proteolytic activity and antibioses against certain test organisms were investigated.The buffer capacity of chopped and macerated plant material before and after fermentation was determined.These studies are still in progress. I am indebted to the Swedish Foundation Fonden för främjande av forsknings-och försöksverksamheten på jordbrukets område for generous financial support. I also gratefully acknowledge the encouraging interest and support of ProfessorRagnar nilsson.     

植物衰老期间生理生化变化的研究进展

植物衰老是受内外因素控制的细胞有序降解并最终导致死亡的过程,衰老期间会出现与正常生长阶段不同的生理生化变化。植物衰老引起的各种功能的下降极大地限制了作物产量潜力的发挥,种子贮存过程中的衰变、逆境条件下植株的早衰、果蔬采后贮藏衰老导致货架寿命的缩短等均会造成极大的经济损失。研究植物衰老的生理机制及其调控具有十分重要的意义。综述了有关植物衰老时生理生化变化方面的近期研究进展,以利于人们对植物衰老生理的更深入的了解。     

Selenium-mediated biochemical changes in Japanese quails

The effect of selenium (Se) on collagen characteristics and glutathione peroxidase (GSH-Px) activity in the skin of Japanese quailsCoturnix coturnix japonica fed a formulated, semipurified, low-Se diet (basal) (0.05 ppm) was investigated. The quails exhibited severe Se-deficiency symptoms and significant reduction in skin GSH-Px activity at the end of 30 d. Selenium supplementation at a 2-ppm level restored the normal skin conditions and enhanced skin GSH-Px activity significantly. But a dietary Se level of 0.1 ppm was found to be inadequate in restoring the general skin conditions and GSH-Px activity. A markedly low total collagen content of about 23% was observed in the skin of quails fed the basal diet, compared to 39% of total collagen content in the skin of the 2-ppm Se-supplemented group. Molecular organization of skin collagen of quails on the basal and 0.1-ppm Se diet showed an abundance of monomeric forms with less crosslinks, compared to the presence of polymeric forms with more crosslinks, indicating enhanced stability in the skin collagen of quails on the 2-ppm diet. The delay in the in vitro fibril formation of collagen from the basal and 0.1-ppm Se groups, compared to a relatively faster rate in the case of the 2-ppm Se group, indicates a disturbance in the aggregation phenomenon of collagen. The increase in skin GSH-Px activity and concurrent increase in polymeric collagen on increasing the dietary Se level suggest a possible role for Se in collagen metabolism.     

Selenium-mediated biochemical changes in Japanese quails

The tissue uptake and distribution of injected [⁷⁵Se]-sodium selenite as a variance with time and as influenced by dietary selenium status was followed in the tissues of Japanese quails,Coturnix coturnix japonica. Quails maintained on a low selenium semipurified (basal) diet and basal diets supplemented with 0.2 and 2.0 ppm selenium as sodium selenite were injected intraperitonially with⁷⁵Se as sodium selenite (2.8 microcuries). The injected⁷⁵Se was monitored in blood, liver, kidney, heart, and testis at 24, 72, and 144 h after injection. Maximal uptake of the injected⁷⁵Se was observed in tissues of quails maintained on basal diet. The uptake of⁷⁵Se in tissues in general was determined by the dietary Se status. Among the organs studied, kidney had the maximal level of⁷⁵Se, 0.2 ppm (μg/g wet tissue) followed by liver, testis, and heart, but testis had the maximal level when the level per milligram of protein was considered, about 3.0 ng/mg protein, followed by liver, kidney, and heart. About 10–20% of the tissue⁷⁵Se was located in the mitochondria and 50–60% in the post-mitochondrial supernatant fractions in all dietary Se levels. Significant incorporation of⁷⁵Se in the mitochondrial membrane was observed. The percent distribution ratio between the membrane and matrix fractions of the mitochondria remained constant at all dietary Se levels which, in liver was 65∶35, in kidney 55∶45, and in testis 75∶25. However, in heart mitochondria, the distribution of⁷⁵Se between membrane and matrix varied with dietary Se status, the ratio being 82∶18 in the basal group, and 72∶28 and 41∶59 in the 0.2 and 2.0 ppm Se-supplemented groups, respectively. This is indicative of a preferential uptake of⁷⁵Se in the mitochondrial membrane in conditions of deficiency. About 40–60% of the mitochondrial membrane-associated⁷⁵Se was released upon Triton treatment in all the organs. Of the membrane-bound⁷⁵Se, about 10–15% was acid-labile in liver and kidney and 25% in the heart tissue. Possibilities of tissue specific roles, especially in the heart mitochondrial membrane-related processes, are indicated for selenium.     

Cultured neuroblastoma cells in biochemical studies

Neuroblastoma is a spontaneous tumour of animals and people. Tumour strains maintained as transplanted tumours and constant cell lines in suspension and monolayer cultures in vitro are obtained. The neuroblastoma cells are able to spontaneous and induced differentiation. The differentiated neuroblastoma cells have many specific properties of nature neurons and are a rather valuable object for solution of many problems in neurochemistry and general cell biology. It is neuroblastoma that has been used to show first the reversibility of neoplastic transformation and to carry out numerous studies to elucidate the mechanisms of cell differentiation. The neuroblastoma cell cultures are a convenient object for studying the ion channels and specifying the role of membrane lipids in their work.     

The scope of moderate pressure changes for kinetic and equilibrium studies of biochemical systems

… but fertility is the result not of exactness but of seeing new problems where none have been seen before, and of finding new ways of solving them…' Karl Popper, Unended Quest (p. 25, Fontana/ Collins Edition)     

Phostoxin-induced biochemical and pathomorphological changes in rabbits

The effect of chronic phostoxin administration on some tissue ATPases, hematology and tissue histopathology was investigated using a combination of gravimetric, enzymatic, colorimetric and histological procedures in New Zealand White rabbits after 2 weeks administration of 0.8mg phostoxin/kg body weight/day, po. The phostoxin treatment led to significant decreases in Na(+)-K+ ATPase activities in renal, hepatic and cardiac tissues. Similar decreases were obtained in the activities of Ca(2+)-ATPase and Mg(2+)-ATPase in liver. In addition, the phostoxin-toxified rabbits manifested significant decreases in hematocrit, red blood cell count, hemoglobin and platelets. Histological examination of the tissues revealed pronounced degenerative changes in liver, heart and kidney.     

Advances in drug discovery and biochemical studies

Japanese researchers continue to discover new means to combat parasites and make important contributions toward developing tools for global control of parasitic diseases. Streptomyces avermectinius, the source of ivermectin, was discovered in Japan in the early 1970s and renewed and vigorous screening of microbial metabolites in recent years has led to the discovery of new antiprotozoals and anthelminthics, including antimalarial drugs. Intensive studies of parasite energy metabolism, such as NADH-fumarate reductase systems and the synthetic pathways of nucleic acids and amino acids, also contribute to the identification of novel and unique drug targets.     

Comparative biochemical studies of carotenoids in catfishes

The carotenoids of 12 species of Siluriformes fishes (eight families) were investigated from a comparative biochemical point of view. The patterns of carotenoids in catfishes belonging to the family Siluridae were quite different from those of the other seven families of catfishes (Bagridae, Amblycipitidae, Clariidae, Plotosidae, Ictaluridae, Callichthyidae and Malapteruridae). 7, 8-Dihydro-beta-carotene; 7, 8, 7', 8'- and 7, 8, 9, 10-tetrahydro-beta-carotene; (3R)-7', 8'-dihydro-beta-cryptoxanthin; 7, 8-dihydrolutein A; 7, 8-dihydrolutein B; parasiloxanthin; 7', 8'-dihydroparasiloxanthin; and 4 or 4'-hydroxyparasiloxanthin were characteristic carotenoids found in only one family, Siluridae, and these carotenoids accounted for 24-60% of total carotenoids. In catfishes belonging to the other seven families except Siluridae, the carotenoid patterns were very similar and the most predominant carotenoid was zeaxanthins (23-56%).     

Protein immunoblot and immunodot in biochemical studies

General notions on the protein immunoblot and immunodot are reported. Possibilities of their wide application in biochemical studies are discussed. The employed materials, the most important operations when performing different variants and modifications of these methods as well as resolution and advisability of their application are comprehensively analyzed.