In physiological property and growing environment aspects, there are some similarities between Acidthiobacillus ferrooxidans(ATF) and magnetotactic bacteria. ATF shows magnetotacxis under the microscope. The magnetosome can be extracted from ATF by using the extracting method of magnetosome from magnetotactic bacteria. The membrane of ATF was crushed by ultrasonic wave and the magnetosomes in the ATF which mainly contains Fe through chemical detection were attracted by using magnetite. After purifing with sucrose density gradient centrifugation and washing by PBS, the magnetosomes can be seen clearly through a transmission electron microscope. The results indicate there are a small amount of intracellular magnetosomes which made the ATF be magnetotactic under the applied magnetic field. It is the first time to find that ATF was magnetotactic. The magnetotaxis of ATF can be utilized and isolated by the magnetotactic properties to gain the high-performance ATF strains of mineral leaching, which have high activity and different magnetism.

Biohydrometallergy technology received more and more attention because of its simple process, low cost and kind to environment, especially in dealing with low-grade and complex minerals. However, it is difficult to optimize microorganism species and process parameters in bioleaching procedure because of the lack of suitable bacteria and quantitative analysis methods at micro-level for bioleaching system. This has resulted in the low efficiency and poor yield of the target metal in bioleaching. With the development of microarray and bacteria conservation technology, solutions to the above problems were being found. This article summarizes the latest findings on genetic elucidation and the community structure of microorganisms in sulfide minerals bioleaching system, in the aim of providing a better understanding on the significance of cross-field technology of biohydrometallergy and genomics.
Acidithiobacillus ; genetics ; isolation & purification ; metabolism ; Industrial Microbiology ; methods ; trends ; Microarray Analysis ; Minerals ; metabolism ; Mining ; methods ; Sulfides ; chemistry ; metabolism

OBJECTIVETo evaluate the effect of the levels of IGF-I in the epididymis and the expression of IGF-I in the testis of adult male rat after the administration of cyclophosphamide.

METHODSNinety-six male adult rats (8 weeks age) were divided into 6 groups. The doses given to the rats of the groups 1 to 5 were 10, 20, 40, 80 and 100 mg/(kg x d), respectively. The remaining group was served as control. All those rats were sacrificed and IGF-I were quantitatively determined by ELISA techniques 2 and 4 weeks after the administration of the drug (by gastric fudge). Immunohistochemical SP technique was used to examine expression of IGF-I in rat testis.

RESULTSThe levels of cell factors (IGF-I) in the epididymis of the rats were gradually reduced with the increasing time and dose after administration of the drug. In the mean time the expression of IGF-I in the tissues of the testis of those rats were also gradually reduced.

CONCLUSIONIn the time of oligozoospermia/azoospermia induced by the administration of cyclophosphamide, the expression levels of IGF-I in the genetic system were significantly reduced. The possible mechanism of these changes could be attributed to the lower spermatogenesis function of the testis caused by the administration of cyclophosphamide.

Animals ; Azoospermia ; chemically induced ; metabolism ; Cyclophosphamide ; toxicity ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Epididymis ; metabolism ; Immunohistochemistry ; Insulin-Like Growth Factor I ; biosynthesis ; Male ; Oligospermia ; chemically induced ; metabolism ; Rats ; Rats, Sprague-Dawley ; Testis ; metabolism

The extreme microorganisms Ferroplasma spp., play an important role in bioleaching of sulphide ores at low pH value and temperatures around 50 degrees C. Without cell wall, Ferroplasma spp. is sensitive to pulp density, shearing force and heavy metal ions. Thus it is difficult to obtain their high cell density cultures, which limits the large-scale industrial application. In this paper, the optimum culture conditions of Ferroplasma thermophilum were studied by shaking culture. The results showed that the optimum culture conditions are as follows: 50 degrees C, initial pH 0.5, 50 mL working volume in 250 mL shaking-flask, inorganic nitrogen source (NH4)2SO4. The optimum combination of FeSO4.7H2O, yeast extract and peptone was determined by orthogonal experiments, including FeSO4.7H2O 40 g/L, yeast extract 0.3 g/L, peptone 0.2 g/L. Under the optimum culture conditions, the cell density was up to 6.3 x 10(7) cell/mL, and the oxidation of 40 g/L ferrous sulfate heptahydrate was finished in less than 72 hours. The results might provide information for scale-up of archaeon culture as well as its industrial application.
Archaea ; cytology ; growth & development ; Cell Culture Techniques ; methods ; Culture Media ; Hydrogen-Ion Concentration ; Metallurgy ; Temperature

Autophagy is a conserved and programmed catabolic process that degrades damaged proteins and organelles. But the underlying mechanism and functions of autophagy in the ischemia-reperfusion (IR)-induced injury are unknown. In this study, we employed simulated IR of N2a cells as an in vitro model of IR injury to the neurons and monitored autophagic processes. It was found that the levels of Beclin-1 (a key molecule of autophay complex, Beclin-1/class III PI3K) and LC-3II (an autophagy marker) were remarkably increased with time during the process of ischemia and the process of reperfusion after 90 min of ischemia, while the protein kinases p70S6K and mTOR which are involved in autophagy regulation showed delayed inactivation after reperfusion. Administration of 3-methyladenine (3MA), an inhibitor of class III PI3K, abolished autophagy during reperfusion, while employment of rapamycin, an inhibitor of mTORC1 (normally inducing autophagy), surprisingly weakened the induction of autophagy during reperfusion. Analyses of mitochondria function by relative cell viability demonstrated that autophagy inhibition by 3-MA attenuated the decline of mitochondria function during reperfusion. Our data demonstrated that there were two distinct dynamic patterns of autophagy during IR-induced N2a injury, Beclin-1/class III PI3K complex-dependent and mTORC1-dependent. Inhibition of over-autophagy improved cell survival. These suggest that targeting autophagy therapy will be a novel strategy to control IR-induced neuronal damage.
Adenine ; analogs & derivatives ; pharmacology ; Animals ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Autophagy ; Beclin-1 ; Cell Line, Tumor ; Cell Survival ; Mechanistic Target of Rapamycin Complex 1 ; Mice ; Mitochondria ; metabolism ; Multiprotein Complexes ; antagonists & inhibitors ; metabolism ; Neurons ; drug effects ; metabolism ; Neuroprotective Agents ; pharmacology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Reperfusion Injury ; metabolism ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism