新疆优良苜蓿根瘤菌株CX103和CX107的生理生化特性

新疆优良苜蓿根瘤菌株ＣＸ１０３和ＣＸ１０７的生理生化特性黄玲（新疆农科院微生物研究所乌鲁木齐，８３００００）新疆干旱少雨，为典型的干旱和半干旱气候，在这种独特的环境下生存着具有相应特性的微生物。我们从新疆不同生态环境下采集到苜蓿根瘤菌菌株１０多种，经...

蚯蚓生物制剂对小麦幼苗生理代谢和生长的影响

蚯蚓生物制剂对小麦生理代谢和生长的影响研究表明，在小麦种子萌发期，过氧化氢酶、酸性磷酸酯酶活性和三磷酸腺苷含量分别比对照提高１１９．１％、１１．４％和３７．５％。在小麦幼苗时期，硝酸还原酶活性和幼苗吸收磷的能力分别比对照提高９８．６％和２８．２％。在小麦发芽期，种子活力指数比对照提高２８．９％。小麦三叶期苗高、根长和干重分别比对照提高１３．２％，１９．２％和２４．１％。

Screening of a Novel Bioflocculant-producing Strain and Research on Its Flocculation

[Objective] This study aimed to screen a bacterial strain capable of producing bioflocculant. [Method] A bacterial strain T-11 capable of producing bioflocculant was isolated from activated sludge. Detailed tests on the morphological, physiological and biochemical characteristics were carried out and identification was performed to identify the strain. Finally, the bioflocculant was isolated and purified, and the flocculating activity and chemical characteristics were measured. [Result] It was identified as Serratia plumuthica based on its morphological, physiological and biochemical characteristics. This strain secreted flocculant best in a culture medium which included sucrose and NaNO3. The maximal cell growth was achieved within 10 h and the flocculating activity paralleled to it. It was found to be effective for flocculation of kaolin suspension, when added at a final concentration of 0.7 mg/L, over a range of pHs （2-7）, and temperature （approximately 30-80 ℃）. Chemical analysis indicated that the bioflocculant was an acidic polysaccharide consisting of glucose, glucuronic acid and galactose, talose and altrose. Infrared spectrum analysis also revealed typical characteristics of polysaccharides. [Conclusion] The biofloccu- lants produced by strain T-11 can greatly improve the ability of activated sludge to settle.

Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

To investigate the characteristics and metabolic mechanism of short-cut denitrifying phospho- rus-removing bacteria （SDPB） that are capable of enhanced biological phosphorus removal （EBPR） using nitrite as an electron acceptor, an aerobic/anoxic sequencing batch reactor was operated under three phases. An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological, physiological, biochemical properties and 16S rDNA gene sequence analysis. Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand （COD）, phosphate, nitrite, poly-fl-hydroxybutyrate （PHB）, and glycogen. The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans. As a kind of non-fermentative bacteria, the energy of strain YC was mainly generated from phosphorus release （96.2%） under anaerobic conditions with 0.32 mg P per mg synthesized PHB. Under anoxic conditions, strain YC accumulated 0.45 mg P per mg degraded PHB, which produced most of energy for phosphate accumulation （91.3%） and a little for glycogen synthesis （8.7%）. This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms （PAOs）. It is also found that PHB, a kind of intracellular polymer, plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification. Therefore, monitoring AP/APHB and ANO2 -N/APHB is more necessary than monitoring AP/ACOD, ANO2 -N/ACOD, or AP / ANO2 -N.

Bile acids:Chemistry,physiology,and pathophysiology

The family of bile acids includes a group of molecular species of acidic steroids with very peculiar physical-chemical and biological characteristics.They are synthesized by the liver from cholesterol through several complementary pathways that are controlled by mechanisms involving finetuning by the levels of certain bile acid species.Although their best-known role is their participation in the digestion and absorption of fat,they also play an important role in several other physiological processes.Thus,genetic abnormalities accounting for alterations in their synthesis,biotransformation and/or transport may result in severe alterations,even leading to lethal situations for which the sole therapeutic option may be liver transplantation.Moreover,the increased levels of bile acids reached during cholestatic liver diseases are known to induce oxidative stress and apoptosis,resulting in damage to the liver parenchyma and,eventually,extrahepatic tissues.When this occurs during pregnancy,the outcome of gestation may be challenged.In contrast,the physical-chemical and biological properties of these compounds have been used as the bases for the development of drugs and as pharmaceutical tools for the delivery of active agents.

Proteome Profiles of Longissimus and Biceps Femoris Porcine Muscles Related to Exercise and Resting

Exercise affects muscle metabolism and composition in the untrained muscles. The proteome of muscle tissue will be affected by exercise and resting. This is of economic importance for pork quality where transportation relates to exercise of untrained muscles. Rest reverses exercise effects. The objective of this research was to develop potential protein biomarkers that predict the optimal resting time after exercise related to optimal pork quality. Ten litters of four female pigs were within litter allocated to the four treatment groups： exercise by running on a treadmill for 27 minutes followed by rest for 0, 1, or 3 h; control pigs without exercise. Proteome profiles and biochemical traits measuring energy metabolism and meat quality traits expected to be related to exercise were determined in the Longissimus and the Biceps femoris of the pigs. The results indicated associations between protein abundances in muscles and exercise, resting, and biochemical traits.

Characteristics of Heavy Metal Circulation in Biosphere

In order to control heavy metal pollution effectively, this paper reviews heavy metal source and transport characteristics in heavy metal circulation in bio- sphere, including geochemical cycle and biological cycle of heavy metals. The inter- body of geochemical cycle of heavy metals includes soil, gas as well as water body, and the interbody of biological cycle of heavy metals includes environment, plant, microorganisms and animals. As to macro-cycle, transportation character in each interbody is different. Heavy metal circulation in different interbody interacts with each other and is in dynamic balance. Heavy metals in soil include two parts, i.e. active and inert forms, which are in dynamic equilibrium. This equilibrium may be affected by different physicochemical factors. Heavy metal content at different soil depth reflects historical accumulation level of heavy metal. In contrast to agri- cultural eco-system itself, industrial and urban activities are of great menace. Fluvial transport and atmospheric input are significant pathways of heavy metal circulation. Sludge plays an accumulative role of heavy metals, and can release its heavy met- als to water body causing secondary pollution. Balance of heavy metal immobiliza- tion and release is interrupted by physicochemical characters and microbial activity. Temperature can influence atmospheric heavy metal content, and volatile heavy meal precipitation is an indLspensable source in soil and water body. In regard to micro-cycle, plants is the main part in heavy metal cycle, microorganisms play roles in accelerator and animals in recipient. Specific transportation and assigned location of heavy metal in plants are adopted to keep internal heavy metal equilibrium.

Effects of basic fibroblast growth factor on biological characteristics of osteoblasts

Objective: To elucidate the effects of exogenous basic fibroblast growth factor ( bFGF ) on biological characteristics of rat osteoblasts cultured in vitro.Methods: The osteoblasts isolated from a Sprague-Dawley rat and cultured in vitro were treated with different concentrations of bFGF (5-50 ng/ml) respectively. At 24 hours after treatment, the proliferating cell nuclear antigen was measured with immunocytochemistry, alkaline phosphatase ( ALP) activity was determined and the expression of transforming growth factor beta 1 (TGF-β1) was detected to observe the effects of bFGF on growth and differentiation of osteoblasts. Results: bFGF ( 5-50 ng/ml ) could obviously promote the growth of osteoblasts. The intracellular expression of TGF-β, mRNA increased significantly, but the intracellular ALP content decreased.Conclusions: bFGF can obviously stimulate the proliferation of osteoblasts and promote the synthesis of TGF-β1, but cannot promote the differentiation of osteoblasts.