Biosynthetic Profile in the Co-culture of Aspergillus sydowii and Bacillus subtilis to Produce Novel Benzoic Derivatives.

Microbial co-culture simulates the natural ecosystem through the combination of artificial microbes. This approach has been widely applied in the study of activating silent genes to reveal novel secondary metabolites. However, there are still challenges in determining the biosynthetic pathways. In this study, the effects of microbial co-culture on the morphology of the microbes were verified by the morphological observation. Subsequently, through the strategy combining substrate feeding, stable isotope labeling, and gene expression analysis, the biosynthetic pathways of five benzoic acid derivatives N1-N4 and N7 were demonstrated: the secondary metabolite 10-deoxygerfelin of A. sydowii acted as an inducer to induce B. subtilis to produce benzoic acid, which was further converted into 3-OH-benzoic acid by A. sydowii. Subsequently, A. sydowii used 3-OH-benzoic acid as the substrate to synthesize the new compound N2, and then N1, N3, N4, and N7 were biosynthesized upon the upregulation of hydrolase, hydroxylase, and acyltransferase during co-culture. The plate zone analysis suggested that the biosynthesis of the newly induced compounds N1-N4 was mainly attributed to A. sydowii, and both A. sydowii and B. subtilis were indispensable for the biosynthesis of N7. This study provides an important basis for a better understanding of the interactions among microorganisms, providing new ideas for studying the biosynthetic pathways of the newly induced secondary metabolites in co-culture.

Pathways and determinants of early spontaneous vegetation succession in degraded lowland of South China.

Continuous and prolonged human disturbances have caused severe degradation of a large portion of lowland in South China, and how to restore such degraded ecosystems becomes an increasing concern. The process and mechanisms of spontaneous succession, which plays an important role in vegetation restoration, have not been adequately examined. To identify the pathways of early spontaneous vegetation succession, 41 plots representing plant communities abandoned over different times were established and investigated. The communities and indicator species of the vegetation were classified by analyzing the important values of plant species using multivariate analyses. The results indicated that the plant species could be classified into nine plant communities representing six succession stages. The pathway and species composition also changed in the process of succession. We also measured 13 environmental variables of microtopography, soil structure and soil nutrition in each plot to examine the driving forces of succession and the vegetation-environment relationships. Our results showed that the environmental variables changed in diverse directions, and that soil bulk density, soil water capacity and soil acidity were the most important factors.

A primary investigation on disseminated histoplasmosis in Hubei / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the epidemiologic features of disseminated histoplasmosis (PDH) in Hubei province.</p><p><b>METHODS</b>Bone marrow smears of 12 patients diagnosed as Kala-azer in Hubei province including 4 patients in Jingsan, 2 patients in Shashi and each 1 in Yichang, Jinmen, Zhongxiang, Luotian, Xianning and Guanghua respectively were re-examed under microscope. Peripheral blood and bone marrow smears of several patients were detected. After inoculated the bone marrow, peripheral blood, liver and spleen tissue of patients in MLI, the single colony was trans-inoculated in BHIB, SDA and CMA and incubated at 25 degrees C and 35 degrees C. Bone marrow, peripheral blood and bacterial fluid of yeast-phase Histoplasma capsulatum (H.cap) were injected into the abdominal cavity of Kunming mice and nude mice. When symptoms and signs developed, the spleen tissue was separated, then observed under microscope and cultured. Mycelium-phase and Yeast-phase H.cap were inoculated in urase and gelatin medium, then incubated at 25 degrees C and 35 degrees C. Histoplasmin was injected subcutaneously into patients, and then followed for 48 - 72 hours. Amphotericin B was selected to treat the PDH patients.</p><p><b>RESULTS</b>Moriform cell cluster and sausage-shaped cell were not observed in mononuclear-macrophages in the bone marrow smears from 12 patients. Leishman-Donovan body was found only in one patient. There wasn't kinetoplast in the cellular plasm of spores in 11 patients and no transeptae was found. The reaction of H.cap to urease was positive and H.cap did not liquefy the gelatin. It appeared to be mycelium-phase at 25 degrees C but no penicillus and catenulate conidia was found. The characteristic denticle macroconidia was observed but produced red coloring matter. It also appeared to be yeast-phase at 35 degrees C. Yeast-phase spores were observed under microscope. No sausage-shaped spore and transeptae were identified. H.cap could be acquired in the spleen tissue in Kunming mice and nude mice. Bacterium forms, characteristics under microscope and biochemical reaction of mycelium-phase and yeast-phase H.cap were different from some other kinds of dimorphic fungi such as Penicillium marneffei and Histoplasm duboisii etc.</p><p><b>CONCLUSION</b>There were scattered epidemics of PDH in Hubei province. The detection rate of PDH was higher in the southeast area then in the northwest area. The golden standards of clinic diagnosis were mycological culture and inoculation to animals. Amphotericin B was necommended as the first choice for treatment.</p>