Effects of dissolved organic matter from sewage sludge on the atrazine sorption by soils

The effects of dissolved organic matter (DOM), water soluble organic matter derived from sewage sludge, on the sorption of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-trazine) by soils were studied using a batch equilibrium technique. Six paddy soils, chosen so as to have different organic carbon contents, were experimented in this investigation. Atrazine sorption isotherms on soils were described by the linear equation, and the distribution coefficients without DOM (Kd) or with DOM (Kd*) were obtained. Generally, the values of Kd*/Kd initially insoil-solution system form. Critical concentrations of DOM (DOMnp) were obtained where the value of Kd* was equal to Kd. The presence of DOM with concentrations lower than DOMnp promoted atrazine sorption on soils (Kd* ＞ Kd), whereas the presence of DOM with concentrations higher than DOMnp tended to inhibit atrazine sorption (Kd* ＜ Kd). Interestingly, DOMnp for tested soils was negatively correlated to the soil organic carbon content, and the maximum of Kd*/Kd (i.e.Kmax) correlated positively with the maximum of DOM sorption on soil (Xmax). Further investigations showed that the presence of hydrophobic fraction of DOM evidently promoted the atrazine sorption on soils, whereas the presence of hydrophilic DOM fraction obviously tended to inhibit the atrazine sorption. Interactions of soil surfaces with DOM and its fractions were suggested to be the major processes determining atrazine sorption on soils. The results of this work provide a reference to the agricultural use of organic amendment such as sewage sludge for improving the availability of atrazine in soils.     

~（60）Co－γ射线诱变柠檬酸产生菌黑曲霉Co9－6的研究

本试验采用￣（６０）Ｃｏ－γ射线对柠檬酸产生菌黑曲霉Ｃｏ９－６进行辐射,经两次处理后选育出Ｌ１２１７和Ｌ８０１两株优良柠檬酸产生菌。中试结果表明菌株Ｌ１２１７较Ｌ８０１更优：产酸率较菌株Ｃｏ９－６提高１７．６％、发酵周期缩短１３．４％、对糖转化率提高１３．３％。     

Optimal conditions for hepatitis B core antigen production in shaked flask fermentation

The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed (150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production ofEscherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at PH 7, 37°C and at a rotational speed of 250 rpm which is 0.927 h⁻¹. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the highest growth rate (0.927 h⁻¹) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C. The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of the protein yield for theE. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher compared to the lowest yield achieved, at 30°C.     

Range expansion of a habitat-modifying species leads to loss of taxonomic diversity: a new and impoverished reef state

Global climate change is predicted to have major negative impacts on biodiversity, particularly if important habitat-modifying species undergo range shifts. The sea urchin Centrostephanus rodgersii (Diadematidae) has recently undergone poleward range expansion to relatively cool, macroalgal dominated rocky reefs of eastern Tasmania (southeast Australia). As in its historic environment, C. rodgersii in the extended range is now found in association with a simplified 'barrens' habitat grazed free of macroalgae. The new and important role of this habitat-modifier on reef structure and associated biodiversity was clearly demonstrated by completely removing C. rodgersii from incipient barrens patches at an eastern Tasmanian site and monitoring the macroalgal response relative to unmanipulated barrens patches. In barrens patches from which C. rodgersii was removed, there was a rapid proliferation of canopy-forming macroalgae (Ecklonia radiata and Phyllospora comosa), and within 24 months the algal community structure had converged with that of adjacent macroalgal beds where C. rodgersii grazing was absent. A notable scarcity of limpets on C. rodgersii barrens in eastern Tasmania (relative to the historic range) likely promotes rapid macroalgal recovery upon removal of the sea urchin. In the recovered macroalgal habitat, faunal composition redeveloped similar to that from adjacent intact macroalgal beds in terms of total numbers of taxa, total individuals and Shannon diversity. In contrast, the faunal community of the barrens habitat is overwhelmingly impoverished. Of 296 individual floral/faunal taxa recorded, only 72 were present within incipient barrens, 253 were present in the recovered patches, and 221 were present within intact macroalgal beds. Grazing activity of C. rodgersii results in an estimated minimum net loss of approximately 150 taxa typically associated with Tasmanian macroalgal beds in this region. Such a disproportionate effect by a single range-expanding species demonstrates that climate change may lead to unexpectedly large impacts on marine biodiversity as key habitat-modifying species undergo range modification.     

Cutting edge: TNF receptor-associated factor 4 restricts IL-17-mediated pathology and signaling processes

The effector T cell subset, Th17, plays a significant role in the pathogenesis of multiple sclerosis and of other autoimmune diseases. The signature cytokine, IL-17, engages the IL-17R and recruits the E3-ligase NF-κB activator 1 (Act1) upon stimulation. In this study, we examined the role of TNFR-associated factor (TRAF)4 in IL-17 signaling and Th17-mediated autoimmune encephalomyelitis. Primary cells from TRAF4-deficient mice displayed markedly enhanced IL-17-activated signaling pathways and induction of chemokine mRNA. Adoptive transfer of MOG35-55 specific wild-type Th17 cells into TRAF4-deficient recipient mice induced an earlier onset of disease. Mechanistically, we found that TRAF4 and TRAF6 used the same TRAF binding sites on Act1, allowing the competition of TRAF4 with TRAF6 for the interaction with Act1. Taken together, the results of this study reveal the necessity of a unique role of TRAF4 in restricting the effects of IL-17 signaling and Th17-mediated disease.     

Identification of a microtubule-based cytoplasmic motor in the nematode C. elegans

C. elegans contains a microtubule binding protein that resembles both dynein and kinesin. This protein has a MgATPase activity and copurifies on both sucrose gradients and DEAE Sephadex columns with a polypeptide of Mr approximately 400 kd. The ATPase activity is 50% inhibited by 10 microM vanadate, 1 mM N-ethyl maleimide, or 5 mM AMP-PNP; it is enhanced 50% by 0.2% Triton. The 400 kd polypeptide is cleaved at a single site by ultraviolet light in the presence of ATP and vanadate. In these ways, the protein resembles dynein. The protein also promotes ATP-dependent translocation of microtubules or axonemes, "plus" ends trailing. This property is kinesin-like; however, the motility is blocked by 5 microM vanadate, 1 mM N-ethyl maleimide, 0.5 mM ATP-gamma-S, or by ATP-vanadate-UV cleavage of the 400 kd polypeptide, characteristics that differ from kinesin. We propose that this protein is a novel microtubule translocator.     

Identification of Mamu-DPA1, Mamu-DQA1, and Mamu-DRA alleles in a cohort of Chinese rhesus macaques

Rhesus macaques have long been used as animal models for various human diseases; the susceptibility and/or resistance to some of these diseases are related to the major histocompatibility complex (MHC). To gain insight into the MHC background and to facilitate the experimental use of Chinese rhesus macaques, Mamu-DPA1, Mamu-DQA1, and Mamu-DRA alleles were investigated in 30 Chinese rhesus macaques by gene cloning and sequencing. A total of 14 Mamu-DPA1, 17 Mamu-DQA1, and 9 Mamu-DRA alleles were identified in this study. Of these alleles, 22 novel sequences have not been documented in earlier studies, including nine Mamu-DPA1, ten Mamu-DQA1, and three Mamu-DRA alleles. Interestingly, like Mafa-DQA1 and Mafa-DPA1, more than two Mamu-DQA1 and Mamu-DPA1 alleles were detected in one animal in this study, which suggested that they might represent gene duplication. If our findings can be validated by other studies, it will further increase the number of known Mamu-DPA1 and Mamu-DQA1 polymorphisms. Our data also indicated significant differences in MHC class II allele distribution among the Chinese rhesus macaques, Vietnamese cynomolgus macaques, and the previously reported rhesus macaques, which were mostly of Indian origin. This information will not only promote the understanding of Chinese rhesus macaque MHC diversity and polymorphism but will also facilitate the use of Chinese rhesus macaques in studies of human disease.