漆树乳汁道分泌细胞的超微结构及其与生漆产生和分泌关系的研究

漆树(Rhus verniciflua)乳汁道分泌细胞含有丰富的质体、内质网和嗜锇物质。电子显微镜的现察结果表明,嗜锇的生漆成分合成的可能场所是质体和内质网,并且通过内质网分子和小泡群与质膜相互接触并融合以及质膜内褶包被等三种形式释放到质膜和细胞壁之间的间隙中;再经过细胞壁中乳汁道腔形成时断裂了的胞间连丝通道和扩散渗透两条途径,越过细胞壁分泌到乳汁道腔中。细胞核、线粒体、高尔基体以及细胞质基质或多或少也参与了上述过程。     

Nitric oxide regulates ganoderic acid biosynthesis by the S-nitrosylation of aconitase under heat stress in Ganoderma lucidum

Nitric oxide (NO) is an important signalling molecule in stress response of organisms. We previously reported that NO decreases heat stress (HS)-induced ganoderic acid (GA) accumulation in Ganoderma lucidum. To explore the mechanisms by which NO modulates GA biosynthesis under HS, the effect of NO on the reactive oxygen species (ROS) content was examined. The results showed that NO decreased the production of mitochondrial ROS (mitROS) by 60% under HS. Further research revealed that NO reduced the mitROS content by inhibiting aconitase (Acon) activity. The GA content in Acon-silenced (Aconi) strains treated with NO donor did not differ significantly from that in untreated Aconi strains. To study the mechanism by which Acon activity is inhibited, the S-nitrosylation level of Acon was determined. Biotin-switch technology and mass spectrometry analysis were used to show that Acon is S-nitrosylated at the Cys-594 amino acid residue. Substitution of Cys-594 with a Ser, which cannot be S-nitrosylated, abolished the responsiveness of Acon to the NO-induced reduction in its enzymatic activity. These findings demonstrate that NO inhibits Acon activity through S-nitrosylation at Cys-594. In summary, these findings describe mechanism by which NO regulates GA biosynthesis via S-nitrosylation of Acon under HS condition in G. lucidum.     

Phosphorylation of the pro-apoptotic protein BIK: mapping of phosphorylation sites and effect on apoptosis

BIK is a pro-apoptotic BCL-2 family member and is the founding member of a subfamily of pro-apoptotic proteins known as "BH3-alone" proteins. Ectopic expression of BIK induces apoptosis in variety of mammalian cells. BIK complexes with various anti-apoptotic BCL-2 family proteins such as adenovirus E1B-19K and BCL-2 via the BH3 domain. However, the heterodimerization activity of BIK alone is insufficient for its apoptotic activity. Previous studies have shown that phosphorylation regulates the functional activity of both anti-apoptotic and pro-apoptotic members of the BCL-2 family. Here, we have examined phosphorylation of BIK and its effect on the apoptotic activity of BIK. We show that BIK exists as a phosphoprotein and is phosphorylated at residues 33 (threonine) and 35 (serine). Mutation of the phosphorylation sites, in which the Thr and Ser residues were changed to alanine residues, reduced the apoptotic activity of BIK without significantly affecting its ability to heterodimerize with BCL-2. Our results suggest that phosphorylation of BIK is required for eliciting efficient apoptotic activity. Partial purification of the protein kinase from HeLa cell cytoplasmic extracts suggest that BIK may be phosphorylated by a casein kinase II-related enzyme.     

Greenhouse tests on resistance management of Bt transgenic plants using refuge strategies

Experimental evaluation of the effectiveness of resistance management tactics is vital to help provide guidelines for the deployment of transgenic insecticidal crops. Transgenic broccoli expressing a Cry1Ac gene of Bacillus thuringiensis (Bt) and the diamondback moth, Plutella xylostella (L.), were used in greenhouse tests to evaluate the influence of size and placement of nontransgenic refuge plants on changes in resistance allele frequency and pest population growth. In the first test with an initial Cry1Ac-resistance (R) allele frequency of 0.007, P. xylostella were introduced into cages with the following treatments: 0, 3.3, 10, 20, and 100% refuge plants. Results after four generations showed that resistance could be delayed by increasing the proportion of refuge plants in the cage. Population growth was also influenced by refuge size with the highest populations occurring in treatments that had either no refuge plants or all refuge plants. In the second test, we evaluated the effect of refuge placement by comparing 20% separate and 20% mixed refuges. P. xylostella with an initial frequency of resistant alleles at 0.0125 were introduced into cages and allowed to cycle; later generations were evaluated for resistance and population growth. Separating the refuge had a pronounced effect on delaying resistance and slowing establishment of resistant larvae on Bt plants. Combining information from both trials, we found a strong negative correlation between the number of larvae on Bt plants and the mortality of the population in leaf dip bioassays. Results from larval movement studies showed that separate refuges delayed resistance better than mixed refuges because they conserved relatively more susceptible alleles than R alleles and did not increase the effective dominance of resistance.     

Isolation and characterization of 12 microsatellite loci for Michelia coriacea (Magnoliaceae), a critically endangered endemic to Southeast Yunnan, China

By using a modified biotin–streptavidin capture method, a total of 12 microsatellite loci were developed and characterized for Michelia coriacea (Magnoliaceae), a critically endangered endemic to Southeast Yunnan, China. The number of alleles (A) ranged from two to six in 30 samples of this species. The ranges of observed (H _O ) and expected (H _E ) heterozygosities were 0.033–0.8000 and 0.033–0.7910, respectively. Cross-species amplification in M. yunnanensis showed that a subset of these markers holds promise for congeneric species. These polymorphic SSR markers would be useful tools for population genetics studies on M. coriacea and other congeneric species.     

Six new species of the spider genus Spiricoelotes species (Araneae,Agelenidae) from caves in Jiangxi,China

Six new species of the spider genus Spiricoelotes Wang, 2002 are described, Spiricoelotes anshiensis Chen & Li, sp. n. (♂♀), Spiricoelotes chufengensis Chen & Li, sp. n. (♂♀), Spiricoelotes nansheensis Chen & Li, sp. n. (♂♀), Spiricoelotes taipingensis Chen & Li, sp. n. (♂♀), Spiricoelotes xianheensis Chen & Li, sp. n. (♂♀) and Spiricoelotes xiongxinensis Chen & Li, sp. n. (♀). All new species were collected from caves in Jiangxi Province, China.     

Association between CLPTM1L polymorphisms (rs402710 and rs401681) and lung cancer susceptibility: evidence from 27 case–control studies

Genome-wide association studies have identified two SNPs (rs402710 and rs401681) of CLPTM1L at chromosome 5p15.33 as a new lung cancer (LC) susceptibility locus in populations of European descent. Since then, the relationship between these SNPs and LC has been reported in various ethnic groups; however, these studies have yielded inconsistent results. To investigate this inconsistency, we performed a meta-analysis of 27 studies involving a total of 60,828 cases and 109,135 controls for the two polymorphisms to evaluate its effect on genetic susceptibility for LC. An overall random-effects per-allele odds ratio of 1.14 (95 % CI 1.11–1.16, P < 10^?5) and 1.15 (95 % CI 1.12–1.19, P < 10^?5) was found for the rs401681 and rs402710 polymorphism, respectively. Significant results were also observed for under dominant and recessive genetic models. After stratified by ethnicity, significant associations were found among Caucasians and East Asians. In the subgroup analysis by sample size, significantly increased risks were found for these polymorphisms in all genetic models. In addition, we find both rs402710 and rs401681 conferred significantly greater risks for adenocarcinoma and squamous cell carcinoma when stratified by histological type of tumors. Furthermore, associations of these polymorphisms with LC risk were observed among current smokers and former smokers, as well as never smokers. Our findings demonstrated that rs402710 and rs401681 are risk-conferring factors for the development of lung cancer.