Structure of a Pancreatic ATP-Sensitive Potassium Channel

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A quadratic correlation between long‐term mean group size and group density in a cooperatively breeding passerine

Both mean group size (MGS) and mean group density (MGD) are critical indices to characterize a population of cooperatively breeding birds. When a population reaches its carrying capacity, both long‐term MGS and long‐term MGD will remain relatively stable. However, there has been little study of how these two variables relate. The Masked laughingthrush Garrulax perspicillatus is a cooperatively breeding bird living in fragmented habitats. During 2010 and 2012‐2016, we used song playback to observe and confirm the group sizes and territory ranges of the birds and the data of bird presence to determine habitat suitability. By grouping the nearest territories according to their geographical coordinates, we divided the whole study area into 12 subareas and the whole population into 12 subpopulations. Then, we calculated both MGS and MGD for different time durations for each subpopulation. Finally, using MGD as independent variable and MGS as the dependent variable, we explored the correlations between MGS and MGD by fitting quadratic functions and modeling quadratic regression. Both MGS and MGD were averaged for different time durations and were cross‐related. Our results show that the MGS for more than 2 years significantly correlated with MGD for more than 3 years in a reverse parabolic shape, differing from that of short‐term effects. Our findings suggest that long‐term MGD is a better predictor of long‐term habitat quality and that long‐term MGS is determined by long‐term habitat quality in Masked Laughingthrushes. Based on above findings, we can infer that: (1) Long‐term habitat quality determines the long‐term MGS, but it sets no prerequisite for the status and source of group members; (2) Long‐term MGS in certain populations is adapted to the corresponding level of long‐term habitat quality, it facilitates us to predict the helper effects on current or future survival or reproduction in different situations. These findings and inferences are both helpful for us to understand the evolution of cooperative breeding.     

Establishment of Agrobacterium tumefaciens-Mediated Transformation of an Oleaginous Fungus,Mortierella alpina 1S-4, and Its Application for Eicosapentaenoic Acid Producer Breeding

Gene manipulation tools for an arachidonic-producing filamentous fungus, Mortierella alpina 1S-4, have not been sufficiently developed. In this study, Agrobacterium tumefaciens-mediated transformation (ATMT) was investigated for M. alpina 1S-4 transformation, using the uracil-auxotrophic mutant (ura5⁻ strain) of M. alpina 1S-4 as a host strain and the homologous ura5 gene as a selectable marker gene. Furthermore, the gene for ω3-desaturase, catalyzing the conversion of n-6 fatty acid to n-3 fatty acid, was overexpressed in M. alpina 1S-4 by employing the ATMT system. As a result, we revealed that the frequency of transformation surpassed 400 transformants/10⁸ spores, most of the integrated T-DNA appeared as a single copy at a random position in chromosomal DNA, and most of the transformants (60 to 80%) showed mitotic stability. Moreover, the accumulation of n-3 fatty acid in transformants was observed under the conditions of optimal ω3-desaturase gene expression. In particular, eicosapentaenoic acid (20:5n-3), an end product of n-3 fatty acids synthesized in M. alpina 1S-4, reached a maximum of 40% of total fatty acids. In conclusion, the ATMT system was found to be effective and suitable for the industrial strain Mortierella alpina 1S-4 and will be a useful tool for basic mutagenesis research and for industrial breeding of this strain.Two decades ago, a filamentous zygomycete fungus, Mortierella alpina 1S-4, was isolated from soil as a potent producer of polyunsaturated fatty acids (PUFAs) in our laboratory and was utilized for commercial production of arachidonic acid (AA) (20:4n-6) (21). Breeding of mutants derived from the wild strain led to the production of dihomo-γ-linolenic acid (20:3n-6) and Mead acid (20:3n-9) (10-12) (Fig. ​(Fig.1).1). Furthermore, we attempted to produce other PUFAs synthesized in M. alpina 1S-4, since some fatty acids (e.g., 18:2n-9, 18:4n-3, and 20:4n-3) have limited natural sources and could have promising beneficial physiological effects (9). In particular, for microbial production of n-3 PUFAs, currently prepared from fish oil, it is necessary to achieve stable productivity and quality; however, mutation treatment caused low activity of the specific enzymes involved in PUFA biosynthesis, which is unsuitable for industrial application. In addition, gene manipulation tools have not been sufficiently developed for metabolic control of the PUFA synthetic pathway. Genetic manipulation is a new means of molecularly breeding industrial strains, analyzing their physiological properties, and clarifying the biosynthetic pathway to PUFAs. A comprehensive transformation system for this fungus has been fundamentally established. It involves a uracil-auxotrophic mutant (ura5⁻ strain) as a host strain, a homologous ura5 gene as a selectable marker gene, and transformation through the biolistic method, which is the only effective method (24).Open in a separate windowFIG. 1.Putative biosynthetic pathway of PUFAs in Mortierella alpina 1S-4. OA, oleic acid; LA, linoleic acid; ALA, α-linolenic acid; GLA, γ-linolenic acid; SDA, stearidonic acid; EDA, n-9 eicosadienoic acid; DGLA, dihomo-γ-linolenic acid; ETA, n-3 eicosatetraenoic acid; MA, Mead acid. Open and black arrows indicate elongase and desaturase reactions, respectively.Agrobacterium tumefaciens-mediated transformation (ATMT) has been employed for a wide range of plants (7, 27). Recently, it was reported that A. tumefaciens is also able to transfer its DNA to various fungi, including ascomycetes, basidiomycetes, zygomycetes, and oomycetes, as well as to plants (2, 5, 16). Additionally, this bacterium can transform intact cells and spores as well as protoplasts. Under mild conditions, the ATMT system generates a large number of stable transformants, which show vigorous growth, indicating that the ATMT system can be an efficient tool for molecular manipulation of M. alpina 1S-4. Moreover, the frequency of homologous recombination was higher than that with conventional transformation methods (8). In this study, we evaluated the external gene transfer system using the ATMT system and determined the optimal conditions for M. alpina 1S-4. Furthermore, we overexpressed the ω3-desaturase gene to improve n-3 PUFA productivity in an industrial n-6-PUFA-producing strain, M. alpina 1S-4 (18, 20), using ATMT.     

Global indicators of biological invasion: species numbers, biodiversity impact and policy responses

Aim Invasive alien species (IAS) pose a significant threat to biodiversity. The Convention on Biological Diversity’s 2010 Biodiversity Target, and the associated indicator for IAS, has stimulated globally coordinated efforts to quantify patterns in the extent of biological invasion, its impact on biodiversity and policy responses. Here, we report on the outcome of indicators of alien invasion at a global scale. Location Global. Methods We developed four indicators in a pressure‐state‐response framework, i.e. number of documented IAS (pressure), trends in the impact of IAS on biodiversity (state) and trends in international agreements and national policy adoption relevant to reducing IAS threats to biodiversity (response). These measures were considered best suited to providing globally representative, standardized and sustainable indicators by 2010. Results We show that the number of documented IAS is a significant underestimate, because its value is negatively affected by country development status and positively by research effort and information availability. The Red List Index demonstrates that IAS pressure is driving declines in species diversity, with the overall impact apparently increasing. The policy response trend has nonetheless been positive for the last several decades, although only half of countries that are signatory to the Convention on Biological Diversity (CBD) have IAS‐relevant national legislation. Although IAS pressure has apparently driven the policy response, this has clearly not been sufficient and/or adequately implemented to reduce biodiversity impact. Main conclusions For this indicator of threat to biodiversity, the 2010 Biodiversity Target has thus not been achieved. The results nonetheless provide clear direction for bridging the current divide between information available on IAS and that needed for policy and management for the prevention and control of IAS. It further highlights the need for measures to ensure that policy is effectively implemented, such that it translates into reduced IAS pressure and impact on biodiversity beyond 2010.     

Comparable low-level mosaicism in affected and non affected tissue of a complex CDH patient

In this paper we present the detailed clinical and cytogenetic analysis of a prenatally detected complex Congenital Diaphragmatic Hernia (CDH) patient with a mosaic unbalanced translocation (5;12). High-resolution whole genome SNP array confirmed a low-level mosaicism (20%) in uncultured cells, underlining the value of array technology for identification studies. Subsequently, targeted Fluorescence In-Situ Hybridization in postmortem collected tissues demonstrated a similar low-level mosaicism, independently of the affected status of the tissue. Thus, a higher incidence of the genetic aberration in affected organs as lung and diaphragm cannot explain the severe phenotype of this complex CDH patient. Comparison with other described chromosome 5p and 12p anomalies indicated that half of the features presented in our patient (including the diaphragm defect) could be attributed to both chromosomal areas. In contrast, a few features such as the palpebral downslant, the broad nasal bridge, the micrognathia, microcephaly, abnormal dermatoglyphics and IUGR better fitted the 5p associated syndromes only. This study underlines the fact that low-level mosaicism can be associated with severe birth defects including CDH. The contribution of mosaicism to human diseases and specifically to congenital anomalies and spontaneous abortions becomes more and more accepted, although its phenotypic consequences are poorly described phenomena leading to counseling issues. Therefore, thorough follow-up of mosaic aberrations such as presented here is indicated in order to provide genetic counselors a more evidence based prediction of fetal prognosis in the future.     

能源植物杂交狼尾草对NaCl胁迫的响应及其耐盐阈值

以能源植物杂交狼尾草(Pennisetum americanum × P. purpureum)为实验材料, 用沙培盆栽的方法, 分别用0、0.3%、0.5%、0.9%和1.2%的NaCl处理4周后, 测定植株鲜重、干重、含水量、株高、分蘖数和不同部位的离子含量, 以确定其耐盐阈值和耐盐方式。结果表明, 随着NaCl浓度的增加, 杂交狼尾草的鲜重、干重、株高和分蘖数都显著降低, 地上部分鲜重和干重分别在NaCl浓度为0.568%和0.570%时下降了50%, 1.2% NaCl处理的杂交狼尾草几乎全部死掉。表明杂交狼尾草的耐盐阈值为0.57%; 但植株含水量和功能叶的Na⁺含量变化不明显, 老叶Na⁺含量在NaCl浓度为0.9%时明显升高, 是对照的2倍; 随NaCl浓度的升高, 根中的Na⁺含量显著升高, 在NaCl浓度为0.9%时, 根中的Na⁺含量达到对照的3倍以上。Na⁺含量在功能叶, 老叶和根中含量依次升高; 随NaCl浓度的升高, 地上部分和根中的K⁺含量都无明显变化; 随NaCl浓度的升高, 根中的Na⁺/K⁺明显增加, 而地上部分Na⁺/K⁺只有当NaCl浓度为0.9%时明显增加。以上结果表明杂交狼尾草具有一定的耐盐性, 其耐盐方式为拒盐, 耐盐阈值为0.57% (约100 mmol·L^-1)。     

高山峡谷地区无线电遥测与GPS 空间定位的比较:野外放归大熊猫的跟踪定位

以佩戴具有无线电发射功能的GPS 颈圈(Lotek GPS_ 4400M) 的放归大熊猫“祥祥”作为目标动物, 2006 年4 月至2007 年2 月,采用无线电遥测技术(RT)和GPS 跟踪技术在卧龙自然保护区的“五一棚”区域, 每日监测大熊猫在野外环境下的生存状况、移动规律和觅食行为。为了比较RT 和GPS 在高山峡谷地区空间定位的可行性和有效性,我们引入空间定位率、地形特征、空间定位差、巢域大小和日移动距离等指标来分析RT 和GPS 之间的定位差异。结果表明:RT 的空间定位效率明显高于GPS 的自动定位(P < 0. 001),分别是54.1%(绘图法)和45. 2% (≧ 2D);不同月份RT 和GPS 的空间定位率之间具有显著性差异(P < 0. 05),这与大熊猫不同月份的海拔活动范围和觅食行为特性密切相关。RT 位点的地形指数中坡度高于GPS,坡向和海拔高度较GPS 定位点低,两种无线电遥测方法(两点直接计算法和绘图法)之间没有显著性差异(P > 0.05);同一天位点之间的距离(空间定位差)平均450 ～ 660 m 左右;RT 与GPS 所估测的大熊猫巢域大小,除5 月、9 月和12月RT 低于GPS 外,其余月份为前者高于后者,但无显著性差异(P > 0. 05);日移动距离除12 月份RT 小于GPS 外,其余月份都呈现出RT 大于GPS 的格局,统计检验结果两者之间差异显著(P < 0. 05);两种无线电遥测方法所测指数之间都无明显差异(P > 0. 05)。这说明RT 遥测和GPS 定位都可以应用于高山峡谷地区野生动物的生态学研究,而且GPS 无线电颈圈在亚高山和高山森林中具有可行性和有效性。     

Altered glutathione homeostasis in heart augments cardiac lipotoxicity associated with diet-induced obesity in mice

Obesity-related cardiac lipid accumulation is associated with increased myocardial oxidative stress. The role of the antioxidant glutathione in cardiac lipotoxicity is unclear. Cystathionine β-synthase (Cbs) catalyzes the first step in the trans-sulfuration of homocysteine to cysteine, which is estimated to provide ～50% of cysteine for hepatic glutathione biosynthesis. As cardiac glutathione is a reflection of the liver glutathione pool, we hypothesize that mice heterozygous for targeted disruption of Cbs (Cbs(+/-)) are more susceptible to obesity-related cardiolipotoxicity because of impaired liver glutathione synthesis. Cbs(+/+) and Cbs(+/-) mice were fed a high fat diet (60% energy) from weaning for 13 weeks to induce obesity and had similar increases in body weight and body fat. This was accompanied by increased hepatic triglyceride but no differences in hepatic glutathione levels compared with mice fed chow. However, Cbs(+/-) mice with diet-induced obesity had greater glucose intolerance and lower total and reduced glutathione levels in the heart, accompanied by lower plasma cysteine levels compared with Cbs(+/+) mice. Higher triglyceride concentrations, increased oxidative stress, and increased markers of apoptosis were also observed in heart from Cbs(+/-) mice with diet-induced obesity compared with Cbs(+/+) mice. This study suggests a novel role for Cbs in maintaining the cardiac glutathione pool and protecting against cardiac lipid accumulation and oxidative stress during diet-induced obesity in mice.     

Composition and variability of biofouling organisms in seawater reverse osmosis desalination plants

Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends.