DNA分子标记在动物个体识别与亲权鉴定方面的应用

自从DNA分子标记技术建立以来,各种DNA分子标记相继被广泛地应用于遗传图谱的构建,评估遗传多样性以及个体识别,亲权鉴定等方面,综述了利用DNA分子标记技术,进行动物个体识别与亲权鉴定的原理,研究进展,现状及其应用前景与存在的问题。     

Xanthan fermentations in water/oil dispersions

Summary Xanthan fermentations in W/O dispersions performed better than the control in both small flasks and a 6.6-L fermentor. The better bulk mixing and oxygen transfer achieved in the dispersion resulted in a still rising xanthan concentration of 65 g/L, compared with 26 g/L in the control. A phase inversion phenomenon was observed when n-hexadecane recovered from previous runs was used as the oil.     

Aurintricarboxylic Acid Protects Hippocampal Neurons from NMDA-and Ischemia-Induced Toxicity In Vivo

Abstract: The polymeric dye aurintricarboxylic acid (ATA) has been shown to protect various cell types from apoptotic cell death, reportedly through inhibition of a calcium-dependent endonuclease activity. Recent studies have indicated that there may be some commonalities among apoptosis, programmed cell death, and certain other forms of neuronal death. To begin to explore the possibility of common biochemical mechanisms underlying ischemia-or excitotoxin-induced neuronal death and apoptosis in vivo, gerbils or rats subjected to transient global ischemia or NMDA microinjection, respectively, received a simultaneous intracerebral infusion of ATA or vehicle. As a biochemical marker of neuronal death, spectrin proteolysis, which is mediated by activation of calpain I, was measured in hippocampus after 24 h. ATA treatment resulted in a profound reduction of both NMDA-and ischemia-induced spectrin proteolysis, consistent with the possibility of some common mechanism in apoptosis and other forms of neuronal death in vivo.     

Brackish Eutrophic Water Treatment by Iris pseudacorus L.-Planted Microcosms: Physiological Responses of Iris pseudacorus L. to Salinity

Iris pseudacorus L. has been widely used in aquatic ecosystem to remove nutrient and has achieved positive effects. However, little is known regarding the nutrient-removal performance and physiological responses of I. pseudacorus for brackish eutrophic water treatment due to high nutrients combined with certain salinity levels. In this study, I. pseudacorus-planted microcosms were established to evaluate the capacity of I. pseudacorus to remove excessive nutrients from fresh (salinity 0.05%) and brackish (salinity 0.5%) eutrophic waters. The degradation of total nitrogen and ammonia nitrogen were not affected by 0.5% salinity; 0.5% salinity promoted the degradation of nitrate nitrogen while severely inhibited the degradation of total phosphorus. Additionally, 0.5% salinity was found to induce stress responses quantified by measuring six physiological indexes. Compared to 0.05% salinity, 0.5% salinity resulted in significant decreases in the chlorophyll a, b and total chlorophyll contents of I. pseudacorus which closely related to photosynthesis (p < 0.05). Furthermore, the higher proline, malondialdehyde contents and antioxidant enzyme activities were detected in I. pseudacorus exposed to 0.5% salinity, which provided protection against reactive oxygen species. The results highlight that the cellular stress assays are efficient for monitoring the health of I. pseudacorus in salinity shock-associated constructed wetlands.     

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.