Population dynamics of Trichoderma species in the rhizosphere of tobac co and four species form China

To study the effect of tobacco growth on Trichoderma population, we in vestigated the occurrence of Trichoderma species in the rhizosphere of tob acco plant during the period from transplanting (June) to harvesting (October) and measured relative environmental factors. Eleven species of Trichoderma we re isolated, among which T.harzianum, T.viride, T.hamatum, T.atroviride, T.lo ngibrachiatum, T.virens, T.koningii were identified, other four species Ty1, Ty2, Ty3, Ty4 are new species. Of the species which occurred at high frequencies , T.harzianum and T.hamatum were most abundant in the July and T. viride in the August. The occurrence of the above three abundant species corr elates significantly with the developmental phase of tobacco and correlates appa rently with the soil moisture content, but not with the temperature. For the oth er eight species, no obvious correlation was found between the above factors and them. Based on nucleotide sequences of the internal transcribed spacer (ITS) regions of the rDNA cluster (ITS1and 2) and partial sequences of translation elongation f ac tor 1-alpha (tef1a), phylogenetic position of four new species was determined. Ty2 is additions to Trichoderma section and Ty3.Ty9.Ty10 are additions to sec tion Pachybasium.

Antibacterial Activities of Neolignans Isolated from the Seed Endotheliums of Trewia nudiflora

Five neolignans including four new ones were obtained from the seed endotheliums of Trewia nudiflora L. Their structures were determined to be 9'-methyl americanol A(1), 9'-methyl isoamericanol A(2), 9'-ethyl americanol A(3), 9'-butyl americanol A(4), and americanin (5). Two acetylated products 3,4-diacetyl americanin (5a) and 3,4,9-triacetyl americanin (5b) had been prepared from compound 5. All of these compounds were investigated on antibacterial assays when carbenicillin sodium, streptomycin sulfate and rifampicin were used as positive controls. Compounds 4 and 5 exhibited antibacterial activities against gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Mycobacterium tuberculosis at the minimum inhibitory concentrations (MIC) of 50μg/mL and 100μg/mE respectively, but 5a and 5b did not exhibit antibacterial activity at 200μg/disk.

Recent advance of nematophagous fungi from China and with a special case on Clonostachys rosea (Gliocladium roseum)

China is one of the twelve prolific biological diversity countries in the world, and nematophagous fungol resources are very abundant. In this paper, the research advance of nematophagous fungi is discussed from six aspects: resources introduction, biology of nematophagous fungi, the application of biocontrol agents, fungistsis in soils, research on nematicidal metabolites and molecular biology on nematophagous fungi. Concerning Clonostachys rosea, the alkaline protease (designated Lmz1) was purified from supernatant of C. rosea which showed a molecular mass of 33 kDa, pI of pH 10.5, optimum temperature of 55- 60 ℃. and optimum pH between 11.0-12.0. N-terminal sequence of Lmz1 was determined by electoblotting enzyme protein to PVDF membrane as NH2-A-T-Q-S-N-A-P-?-?-?. The degenerate primer was designed according to terminal sequence for cDNA gene encoding mature protein of Lmz1 by 3’RACE system for rapid amplification of cDNA ends. To express successfully a fungal alkaline protease (Lmz1) in a high level expression system. The specific primers with EcoRI recognition site and extra bases were designed. The cDNA gene encoding mature protease (Lmz1) was amplified with high fidelity pfu DNA polymerase and specific primers against total cDNA population of C. rosea. The recombinant expression vector contain desired DNA fragment was correctly constructed and introduced into yeast host Pichia pastoris GS115 by electroporation. The recombinant alkaline protease was characterized by protease activity, PCR amplification against yeast total DNA, ELISA and western blotting. It demonstrated a molecular mass of 42 kDa based on blot analysis. The expression level of Lmz1 was approximately 9 mg/mL by UV spectrophotometric method.

INITIAL ATMOSPHERIC CORROSION OF ZINC IN THE PRESENCE OF NH_4Cl

Influence of NH_4 Cl on the initial atmospheric corrosion of zinc was investigated viaquartz crystal microbalance (QCM) in laboratory at 80%RH and 25℃. The resultsshow that NH_4 Cl can accelerate the initial corrosion of zinc. Mass gain increase withthe exposure time, but mass gain in the later doesn't change obviously due to theformation of the insoluble simonkolleite on zinc surface in the presence of NH_4 Cl.Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) wasused to characterize the corrosion products. Zn_5Cl_2(OH)_8·H_2O,(NH_4)_2ZnCl_4 andZnO are the corrosion products on zinc. Brief discussion on the mechanisms of at-mospheric corrosion of zinc in the presence of NH_4 Cl was introduced.

A New Saponin Transformed from Ginsenoside Rh_1 by Bacillus subtilis

A novel saponin was isolated from the transformed products of ginsenoside Rh1 by Bacillus subtilis. It's structure was determined to be 3-O-β-D-glucopyranosyl-6-O-β-D-gluco- pyranosyl-20 (S)-protopanaxatriol on the basis of the spectral data.

Purification and characterization of an extracellular protease from Clonostachys rosea

An extracellular protease from Clonostachys rosea (syn . Gliocladium roseum) was purified to SDS-PAGE homogeneity with 14-fold purification by ultrafiltration、ammonium sulfate precipetation、hydrophobic interaction chromatography and anion exchange chromatography. The molecular weight of the protease was 32 kDa as estimated by SDS-PAGE. The N-terminal sequence of first 10 amino acids was A-T-Q-S-N-A-P-W-G-L. This enzyme exhibited pH and temperature optima of 9-10 and 60 ℃, respectively, and was stable over a wide range of pH 4-10 and temperature 4-50 ℃. It did not require Ca 2+. for activity and thermal stability. Pre-incubation of enzyme with Zn 2+., Cu 2+., Hg 2+., Fe 3+. inhibited most of the enzyme activity, but Mn 2+. increased enzyme activity up to 38%. It remained stable in the presence of Tween20, H 2O 2, EDTA. The inhibition profile of the enzymes by PMSF, suggested that this purified protease belongs to the serine protease family. The protease could immobilize nematodes (Panagrellus redivirus) in bioassays and hydrolyzed proteins of the purified cuticle.

Karyotype differentiation and reproductive isolation among natural populations of Drosophila lacertosa

Drosophila lacertosa is widely distributed from northern India to Far East of Russia throughout China.We have studied geographical distributions of three kinds of chromosomal karyotypes,type D(2n=10,4 pairs of V-shaped metacentric chromosomes and a pair of micro-chromosomes),type L(2n= 10,5V with a pair of large-sized heterochromatic autosomes)and type M(2n=10,5V with middle-sized ones).Type D was found exclusively in local populations of D.lacertosa distributed in Yun-Gui Plateau,southwestern China.Both type L and M have a wide range of distribution,and the former occurred in subtropical regions of China including Taiwan Island,whereas the latter in cool temperate regions of East Asia covering Far East of Russia,Korea and the Japan Islands.A strong premating isolation was detected between flies with type D and those with type L or M.These data demonstrate that genetic differentiation leading to cryptic speciation might have occurred in natural populations of Drosophila lacertosa.

Molecular genetic basis for the rhino mouse from Chinese KM subcolony

Both the rhino mouse and hairless mouse resulted from hairless gene mutation, but they show different phenotypes of skin physiology. The rhino mouse has more similar histological characters to human papular alopecia.Therefore rhino mouse is a good experimental animal model for human papular alopecia. This study reports a hairless mouse named rhino KIZ, arose from KM colony in Kunming Institue of Zoology, by systematic studies on morphology,skin histopathology, gene sequence, pedigree and protein domain analysis. The results demonstrate that a C-to-T transition in exon 11 of hr gene (The mutant gene has been applied for a Chinese patent (patent No. 03135280)) results in the rhino KIZ. The rhino KIZ with clear genetic mechanism will be a useful animal model.

Fast evolution of growth hor-mone receptor in primates and ruminants

Pituitary growth hormone (GH) evolves very slowly in most of mammals, but the evolutionary rates ap- pear to have increased markedly on two occasions during the evolution of primates and ruminants. To investigate the evo- lutionary pattern of growth hormone receptor (GHR), we sequenced the extracellular domain of GHR genes from four primate species. Our results suggested that GHR in mammal also shows an episodic evolutionary pattern, which is consis- tent with that observed in pituitary growth hormone. Fur- ther analysis suggested that this pattern of rapid evolution observed in primates and ruminants is likely the result of coevolution between pituitary growth hormone and its re- ceptor.

Episodic evolution of prolactingene in primates

In the present study, we obtained exon 2―5 of prolactin (PRL) gene from four primate species by PCR and sequencing. Adding other genes available in GenBank, we calculate amino acid substitution rates for prolactin gene in primate. Comparison of nonsynonymous substitution rate to synonymous substitution rate ratios shows no evidence of positive selection for any lineage of primate prolactin gene. According to this and the facts that (i) no sites under positive selection are inferred by using maximum-likelihood method; (ii) among 32 amino acid replacement that occurred along the rapid evolutionary phase, only two are included in the 40 functionally important residues, indicating that amino acid replacement tends to occur in those functionally unimportant residues; (iii) partial of prolactin function is replaced by pla-cental lactogen in primate at the rapid evolutionary phase of prolactin gene, we thus deem that it is relaxation of purifying selection to some extent rather than positive selection that enforces the rapid evolution of primate prolactin gene.