-
[show abstract]
[hide abstract]
ABSTRACT: Being an effective biocontrol agent,Clonostachys rosea possess morphologically two different kinds of conidiophore structures, verticillate and penicillate respectively. However,
the factors that influenced this morphological pleomorphism and its related genetic background remains to be elucidated. In
this study, single-spore isolates were obtained from these two types of conidiophores and observed for their cultural and
morphological characteristics. The stability of pleomorphism was confirmed through three-months of continuous inoculation
and incubation. Additionally, the influences on conidiophore’s morphology under different cultural conditions were also recorded.
Our data indicated that the fungal inhibitor thiabendazole changed the formation of conidiophores with only verticillate type
produced, which subsequently had effects on its abilities to infect the plant pathogenic fungusRhizoctonia solani and nematodesPanagrellus redivivus in our bioassay. However, the genomic analysis by Random Amplified Polymorphic DNA (RAPD) assay showed no obvious differences
detected in the mutant with only verticillate conidiophores and its parent strain, suggesting the change in conidiophore’s
type should be attributed to different transcriptional patterns.
Annals of Microbiology 04/2012; 59(1):39-44. · 0.69 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Suppression subtractive hybridization (SSH) is an effective approach to identify the genes that vary in expression levels during different biological processes. It is often used in higher eukaryotes to study the molecular regulation in complex pathogenic progress, such as tumorigenesis and other chronic multigene-associated diseases. Because microbes have relatively smaller genomes compared with eukaryotes, aside from the analysis at the mRNA level, SSH as well as its modifications have been further employed to isolate specific chromosomal locus, study genomic diversity related with exceptional bacterial secondary metabolisms or genes with special microbial function. This review introduces the SSH and its associated methods and focus on their applications to detect specific functional genes or DNA markers in microorganisms.
Applied Microbiology and Biotechnology 10/2007; 76(4):753-60. · 3.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Bacillus nematocida is a Gram-positive bacterium capable of killing nematodes. Our recent studies identified an extracellular serine protease Bace16 in B. nematocida as a candidate of pathogenic factor in the infection against nematodes, which displayed a high similarity with the serine protease family subtilisin BPN', and the MEROPS ID is S08.034. To further confirm the roles that bace16 played in the mechanism of nematocidal pathogenesis, recombinant mature Bace16 (rm-Bace16) was expressed in Escherichia coli strain BL21 using pET-30 vector system. Bioassay experiments demonstrated that the purified recombinant protease had the ability to degrade nematode cuticles and kill nematodes. In addition, a bace16 knockout mutant of B. nematocida constructed by homologous recombination showed considerably lower proteolytic activity and less than 50% nematocidal activity than the wild-type strain. These results confirmed that Bace16 could serve as an important virulence factor during the infectious process.
Applied Microbiology and Biotechnology 06/2007; 75(1):141-8. · 3.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A neutral protease (npr) (designated Bae16) toxic to nematodes was purified to homogeneity from the strain Bacillus nematocida. The purified protease showed a molecular mass of approximately 40 kDa and displayed optimal activity at 55 degrees C, pH 6.5. Bioassay experiments demonstrated that this purified protease could destroy the nematode cuticle and its hydrolytic substrates included gelatin and collagen. The gene encoding Bae16 was cloned, and the deduced amino acid sequence showed 94% sequence identity with npr gene from B. amyloliquefaciens, but had low similarity (13-43%) with the previously reported virulence serine proteases from fungi or bacteria, which reflected their differences. Recombinant mature Bae16 (rm-Bae16) was expressed in Escherichia coli BL21 using pET30 vector system, and its nematicidal activity confirmed that Bae16 could be involved in the infection process. Our present study revealed that the npr besides the known alkaline serine protease could serve as a potential virulence factor in the infection against nematodes, furthermore, the two proteases with different characteristics produced by the same strain co-ordinated efforts to kill nematodes. These data helped to understand the interaction between this bacterial pathogen and its host.
Archives of Microbiology 07/2006; 185(6):439-48. · 1.43 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To study the association between psychosocial factors and the development of lung cancer.
Case-control matched study was employed in the study. A standardized life event, social support and defense mechanisms interview was administered respectively. Total 118 lung cancer patients who were diagnosed pathologically were chosen as case group, and 118 matched healthy people were as control group. The pair had the same gender, the same race, and the same occupation, and lived in the same area, and the age difference between the two groups was ±3 years.
Univariate analysis showed that smoking, defect of sleeping, alcohol consuming, smoking and drinking during meal, preserved food consuming, irregularity of life increased the risk of lung cancer development (P < 0.05). The scores of life events, social support had no significant difference between two groups (P > 0.05), but the scores of stress life events was higher in cancer group than that in control group. The immature factors of defense mechanisms in cancer group were higher than those in control group (P < 0.05). Multiple qualified logistic regression showed that smoking and defect of sleeping were the main risk factors of lung cancer genesis.
There is certain association between psychosocial factors and lung cancer development. The immature defensive factor is the psychosocial factor of lung cancer genesis, and smoking, defect of sleeping, alcohol consuming, smoking and drinking during meal, preserved food consuming, irregularity of life are the risk factors of lung cancer.
Zhongguo fei ai za zhi = Chinese journal of lung cancer 04/2002; 5(2):92-4.
