Landward and eastward shift of Alaskan polar bear denning associated with recent sea ice changes

Polar bears (Ursus maritimus) in the northern Alaska region den in coastal areas and on offshore drifting ice. We evaluated changes in the distribution of polar bear maternal dens between 1985 and 2005, using satellite telemetry. We determined the distribution of maternal dens occupied by 89 satellite collared female polar bears between 137°W and 167°W longitude. The proportion of dens on pack ice declined from 62% in 1985–1994 to 37% in 1998–2004 (P = 0.044) and among pack ice dens fewer occurred in the western Beaufort Sea after 1998. We evaluated whether hunting, attraction to bowhead whale remains, or changes in sea ice could explain changes in den distribution. We concluded that denning distribution changed in response to reductions in stable old ice, increases in unconsolidated ice, and lengthening of the melt season. In consort, these changes have likely reduced the availability and quality of pack ice denning habitat. Further declines in sea ice availability are predicted. Therefore, we expect the proportion of polar bears denning in coastal areas will continue to increase, until such time as the autumn ice retreats far enough from shore that it precludes offshore pregnant females from reaching the Alaska coast in advance of denning.     

Atlantic snake pipefish (<Emphasis Type="Italic">Entelurus aequoreus</Emphasis>) extends its northward distribution range to Svalbard (Arctic Ocean)

Ecological forecasts predict the immigration of boreal species into Arctic waters as one consequence of rising sea temperatures. Here, we report the finding of Atlantic snake pipefish (Entelurus aequoreus) off the western coast of Spitsbergen at 79°N in August 2006. This syngnathid fish species, which was presumed to be confined to waters south of Iceland, has dramatically increased in population size in its core distribution area in the northeastern Atlantic since 2002, probably in response to greater reproduction success due to higher water temperatures. We conclude that our finding is an indication of the predicted northward extension of the distribution range of boreal species.     

Distribution of anticancer antibiotic daunomycin in the rat heart and kidney revealed by immunocytochemistry using monoclonal antibodies

Two monoclonal antibodies (ADM-1-11 and 79-31 mAbs) were raised against daunomycin (DM) conjugated to bovine serum albumin via the cross-linker N-(gamma-maleimidobutyryloxy)succinimide. The monoclonal antibodies (mAbs) specifically detected DM as well as its analogs doxorubicin and epirubicin, but did not react with other anticancer antibiotics, including pepleomycin, mitomycin C, and actinomycin D. The mAbs reacted strongly with glutaraldehyde-conjugated DM in an enzyme linked immunosorbent assay (ELISA) used as a model system for immunocytochemistry as well as in appropriately pretreated sections of tissues from animals injected with DM. No staining occurred in tissues from uninjected animals. In order to perform DM ICC a number of tissue treatment conditions critical to the detection of low molecular weight substances were employed. Uptake of DM was studied in rats after a single i.v. or i.p. administration of the drug. In the heart, accumulation of DM occurred in nuclei and in the cytoplasm. In the kidney, DM immunoreactivity accumulated in all segments of the nephron except for the proximal tubules. Since the proximal tubules are known to be where a variety of transport systems including P-glycoprotein (Pgp) and organic anion-transporting polypeptides (OATPs) in drug interactions occur, the absence of DM accumulation in these segments may reflect a transport phenomenon depending upon such transporters. The availability of methods to study sites of accumulation of DM offers possibilities for understanding toxic side effects of this drug on the heart and kidney. Moreover, the immunocytochemical methodology developed may prove useful for the localization of other low molecular weight drugs that can be fixed in situ by glutaraldehyde.     

Distribution and biodiversity of rhizobia nodulating Chamaecrista mimosoides in the Shandong peninsula of china

Chamaecrista mimosoides is an annual herb legume widely distributed in tropical and subtropical Asia and Africa. It may have primitive and independently-evolved root nodule types but its rhizobia have not been systematically studied. Therefore, in order to learn the diversity and species affinity of its rhizobia, root nodules were sampled from C. mimosoides plants growing in seven geographical sites along the coast line of Shandong Peninsula, China. A total of 422 rhizobial isolates were obtained from nodules, and they were classified into 28 recA haplotypes. By using multilocus sequence analysis of the concatenated housekeeping genes dnaK, glnII, gyrB, recA and rpoB, the representative strains for these haplotypes were designated as eight defined and five candidate novel genospecies in the genus Bradyrhizobium. Bradyrhizobium elkanii and Bradyrhizobium ferriligni were predominant and universally distributed. The symbiotic genes nodC and nifH of the representative strains showed very similar topology in their phylogenetic trees indicating their co-evolution history. All the representative strains formed effective root nodules in nodulation tests. The correlation between genospecies and soil characteristics analyzed by CANOCO software indicated that available potassium (AK), organic carbon (OC) and available nitrogen (AN) in the soil samples were the main factors affecting the distribution of the symbionts involved in this current study. The study is the first systematic survey of Chamaecrista mimosoides-nodulating rhizobia, and it showed that Chamaecrista spp. were nodulated by bradyrhizobia in natural environments. In addition, the host spectrum of the corresponding rhizobial species was extended, and the study provided novel information on the biodiversity and biogeography of rhizobia.     

陕西汉阴发现朱鹮新分布

中国朱鹮就地保护和易地保护取得的成果使朱鹮分布区的扩大成为可能。2013年6月3日,在陕西汉阴县龙垭镇凤柳村(32°58′N,108°31′E,海拔526 m)发现一对朱鹮(H12♀和B747♂)营巢繁殖,成功出飞3只幼鸟。2014年1月12日,我们又在该地的青泥河畔发现8只朱鹮的越冬觅食群体。其中包括上述繁殖配对及其3只后代、1只来自洋县野生种群的个体(J41)以及2只无法识别身份的个体。同年5月该繁殖配对成功出飞幼鸟4只。自2011年之后,宁陕朱鹮再引入种群的个体与洋县野生个体形成配对,说明两个种群之间存在基因交流。汉阴朱鹮新分布的发现表明,陕西宁陕朱鹮再引入项目的实施增加了朱鹮野生种群(源种群)向秦岭东部地区扩散的速度,还将有利于朱鹮再引入种群(卫星种群)的建立。     

硝酸盐型厌氧铁氧化菌的种类、分布和特性

硝酸盐型厌氧铁氧化(NAFO)是指微生物在厌氧条件下利用硝酸盐或亚硝酸盐作为电子受体,将低价铁(二价铁或零价铁)氧化为高价铁(三价铁)的过程。具有NAFO代谢能力的微生物称为硝酸盐型厌氧铁氧化菌(NAFOM)。NAFO是微生物领域的重大发现,也是环境领域开发新型脱氮技术和地学领域研究铁、氮循环的理论依据。整理文献报道的NAFOM资料,分析NAFOM系统发育性状,探讨典型NAFOM的生态分布及其营养、代谢特性,以期为NAFOM菌种资源的开发、地球铁素和氮素循环的研究、NAFO过程的优化提供借鉴。     

Differential Effect of Plant Lipids on Membrane Organization: SPECIFICITIES OF PHYTOSPHINGOLIPIDS AND PHYTOSTEROLS*

The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains.     

根系盐胁迫对盐生植物和甜土植物的幼苗生长及矿质元素分布的影响

为了解盐胁迫对植物的影响, 研究了根系NaCl 胁迫在温室条件下对盐生植物榄仁(Terminalia catappa)和甜土植物枇杷(Eriobotrya japonica)幼苗生长、矿质元素和灰分含量的影响。结果表明:在根系盐胁迫下, 两种植物幼苗的叶片病斑多分布于中心区, 灰分含量增加, 幼苗的Na⁺-Cl^- 呈极显著的正相关关系, 盐胁迫对两种植物幼苗的5 种矿质元素(Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^-)含量影响不大, 但它们在植物中的分布发生了变化。可见, 盐生植物和甜土植物抗盐性的区别是量上的不同, 没有质的差别。