凝结芽胞杆菌BC01对白羽肉鸡生产性能、免疫器官指数及肠道大肠埃希菌的影响

为研究在饲料中添加凝结芽胞杆菌BC01对白羽肉鸡生产性能、免疫器官指数及肠道大肠埃希菌的影响,将240只白羽肉鸡随机分为4组,试验组1、试验组2、试验组3在饲料中添加凝结芽胞杆菌BC01的终浓度分别为1×10~8、2×10~8、3×10~8 cfu/kg,对照组日粮中不添加任何微生态制剂,饲养6周。结果显示,日粮中添加凝结芽胞杆菌BC01可显著提高肉鸡平均日增重(P0.05),显著降低料重比(P0.05),降低死淘率(P0.05),胸腺指数、法氏囊指数均显著高于对照组(P0.05),降低肠道中的大肠埃希菌数量。结果表明,日粮中添加凝结芽胞杆菌BC01,对肉鸡的生长性能有一定的促进作用,提高饲料转化率,提升肉鸡的免疫力,提高肉鸡饲养的经济价值。凝结芽胞杆菌BC01的最佳添加浓度为每公斤饲料添加2×10~8 cfu/kg。     

Microtubules and the organization of the Golgi complex

Electron microscopic and cytochemical studies indicate that microtubules play an important role in the organization of the Golgi complex in mammalian cells. During interphase microtubules form a radiating pattern in the cytoplasm, originating from the pericentriolar region (microtubule-organizing centre). The stacks of Golgi cisternae and the associated secretory vesicles and lysosomes are arranged in a circumscribed juxtanuclear area, usually centered around the centrioles, and show a defined orientation in relation to the rough endoplasmic reticulum. Exposure of cells to drugs such as colchicine, vinblastine and nocodazole leads to disassembly of microtubules and disorganization of the Golgi complex, most typically a dispersion of its stacks of cisternae throughout the cytoplasm. These alterations are accompanied by disturbances in the intracellular transport, processing and release of secretory products as well as inhibition of endocytosis. The observations suggest that microtubules are partly responsible for the maintenance and functioning of the Golgi complex, possibly by arranging its stacks of cisternae three-dimensionally within the cell and in relation to other organelles and ensuring a normal flow of material into and away from them. During mitosis, microtubules disassemble (prophase) and a mitotic spindle is built up (metaphase) to take care of the subsequent separation of the chromosomes (anaphase). The breaking up of the microtubular cytoskeleton is followed by vesiculation of the rough endoplasmic reticulum and partial atrophy, as well as dispersion of the stacks of Golgi cisternae. After completion of the nuclear division (telophase), the radiating microtubule pattern is re-established and the rough endoplasmic reticulum and the Golgi complex resume their normal interphase structure. This sequence of events is believed to fulfil the double function to provide tubulin units and space for construction of the mitotic spindle and to guarantee an approximately equal distribution of the rough endoplasmic reticulum and the Golgi complex on the two daughter cells.     

Selenium unmasks protective iron armor: A possible defense against cutaneous inflammation and cancer

Background

A link between selenium deficiency and inflammatory skin diseases have been noted by many, but this link is still not well understood. We have previously studied the efficacy of ceramide analogs, based on the fire ant venom Solenopsin A, against our psoriasis animal model. Treatment of animals with solenopsin analogs resulted in significantly improved skin as well as in a coordinate downregulation of selenoproteins, namely Glutathione Peroxidase 4 (GPX4). We thus hypothesize that ferroptosis may be a physiologic process that may protect the skin from both inflammatory and neoplastic processes.

磺酸型及还原型胰岛素A链、B链的低场~1H-NMR谱峰的初步识别

以Varian-XL400核磁谱仪对磺酸型及还原型A链、B链在pH10.76时的低场~1H-NMR谱峰作了初步识别,指出它们的分辨率大大高于S—硫甲基型A链、B链谱峰的分辨率。并研究了十二烷基磺酸锂(LDS)对它们的影响。LDS的疏水尾部使酪氨酸受到疏水基因的屏蔽作用,导致峰值向高场位移。     

Adenine nucleotide metabolism in Azotobacter vinelandii. Two metabolic pathways of AMP degradation

AMP-degrading pathways in Azotobacter vinelandii cells were investigated. AMP nucleosidase (EC 3.2.2.4) was rapidly synthesized and reached a maximum at 24 h, while the activity of 5-nucleotidase (EC 3.1.3.5) specific for AMP, which was negligible during the logarithmic phase of the growth, first appeared in 24 h-cultures, and reached a maximum after complete exhaustion of sucrose from the growth medium (70 h).Cell-free extracts of A. vinelandii of 48 h-cultures hydrolyzed AMP to ribose 5-phosphate and adenine in the presence of ATP, and adenine was deaminated to hypoxanthine. When ATP was excluded, AMP was dephosphorylated to adenosine, which was further metabolized to inosine, and finally to hypoxanthine. Hypoxanthine thus formed was reutilized for the salvage synthesis of IMP under the conditions where 5-phosphoribosyl 1-pyrophosphate was able to be supplied. These results suggest that the levels of ATP can determine the rate of AMP degradation by the AMP nucleosidase- and 5-nucleotidase-pathways. The role of ATP in the AMP degradation was discussed in relation to the regulatory properties of AMP nucleosidase, inosine nucleosidase (EC 3.2.2.2) and adenosine deaminase (EC 3.5.4.4).     

Specific cleavage of chicken αA-globin and human c-Ha-ras genes by two molecular forms of calf thymus topoisomerase I

Summary Two molecular forms of topoisomerase I differing in size and sensitivity to camptothecin were isolated from calf thymus. Mapping of topo I cleavage sites of the cloned chicken ^A-globin and human c-Ha-ras genes was carried out. Camptothecin was shown to affect site specificity of the topoisomerases.     

Cell lineage analysis of Schwann cells in the PNS determined by shiverer-normal mouse chimeras

The myelin of the peripheral nervous system from the shiverer mutant mice is characterized by the absence of myelin basic protein, while the other myelin protein components are present at normal levels. Myelin lamella formation is normal in the shiverer mutant. Therefore, by using antiserum against myelin basic protein, we can distinguish the shiverer from the wild-type control myelin immunohistochemically. To study the cell lineage of Schwann cells, chimeras produced by the aggregation of eight-cell embryos from wild-type mice and shiverer mice have been used. Using myelin basic protein as a marker, it was observed that Schwann cells in the sciatic nerve existed as patches of cells with like-genotype. The patches occurred in a linear array along the axons with some intermingling of Schwann cells. Complete randomization by intermingling of Schwann cells was not observed and clones of Schwann cells may persist as contiguous groups throughout peripheral nerve development.     

Substrate binding site of microsomal cytochrome P-450 directly faces membrane lipids

Cytochrome P-450, purified from liver microsomes of phenobarbital-treated rabbits, was incorporated into dimyristoylphosphatidylcholine liposomes. The binding of benzphetamine to the liposome-bound cytochrome P-450 was examined by measuring the benzphetamine-induced spectral change at various temperatures. The van't Hoff plot of the apparent spectral dissociation constant showed a distinct break at the temperature of phase transition of the synthetic lipid. On the other hand, no such break was observed for benzphetamine binding to microsomal bound cytochrome P-450. These results suggest that the substrate binding site of cytochrome P-450 is embedded in the apolar interior of phospholipid bilayer membranes.     

An indirect fluoresent antibody staining procedure for detection of Vibrio cholerae serovar 01 cells in aquatic environmental samples

An immunofluorescence method for detection of Vibrio cholerae serovar 01 in aquatic environmental samples and enrichment broths is described. Antiserum specific for the 01 somatic antigen was produced in rabbits and used in an indirect fluorescent antibody method incorporating fluoresceinisothiocyanate conjugated anti-rabbit globulin goat serum, and rhodamine isothiocynate conjugated bovine serum albumin as background stain. Comparisons of the immunofluorescent procedure and conventional culture methods for isolation of V. cholerae 01 showed that detection occurred significantly more frequently with the fluorescent antibody system.