基于标本和分布信息评估中国虾脊兰属 植物的濒危状况

兰科植物是生物多样性保护的旗舰类群之一, 但如何客观准确地评估兰科植物的濒危状况, 一直是生物多样性保护中急需解决的问题。本文以中国虾脊兰属(Calanthe)植物为例, 探讨了基于馆藏标本和野外分布信息进行兰科植物红色名录濒危等级评估的利弊。我们的研究表明, 馆藏标本能够比较客观地反映物种地理分布信息和相应的野外居群状况, 但对于物种分布的历史变化和受威胁因素反映不足; 而野外工作对于物种的实际分布状况和受威胁因素等的反映比较客观, 但能发现的物种和居群数量有限, 部分极小种群物种在短时间野外工作中很难发现。我们的研究认为, 有2种虾脊兰属植物应被评估为野外灭绝(EW), 16种应被评估为极度濒危(CR)。可见, 中国虾脊兰属植物濒危的状况远比前人的评估结果要严重得多。     

Spatiotemporal variations of CO2 fluxes in a Cynodon-dominated riparian zone of the Three Gorges Reservoir (TGR), China

Aims Riparian ecosystems play an important role in overall ecosystem function, including the global carbon cycle of terrestrial ecosystems, at both landscape and global scales. Yet few studies have reportedin situmeasurements of CO₂in riparian areas where flooding is a unique disturbance to carbon cycling.     

Structural insights into sphingosine-1-phosphate recognition and ligand selectivity of S1PR3-Gi signaling complexes

Dear Editor, Lipids are essential for all life on earth and play critical roles in energy storage and the formation of cellular membranes.Sphingosine-1-phosphat...     

Genetic diversity and population structure among cultivars of Saccharina japonica currently farmed in northern China

Close to 50% of the annual production of the brown alga Saccharina japonica, about 2 million tons (fresh weight), is produced through farming in Shandong province, China, principally around Rongcheng. Under artificial selection for phenotypic traits (e.g. color, blade length) cultivated strains (cultivars) face the problems of inbreeding depression, which can be caused by the close relationships of the parental plants. Hence, in an attempt to evaluate genetic variations and relationships among cultivars, 15 major farmed cultivars were selected and sampled from seven major hatcheries and analyzed using 15 microsatellite markers. A total of 94 alleles were found across all samples, with allele numbers ranging from three to 17 per locus. All of the cultivars exhibited relatively high levels of genetic diversity, with mean Nei's genetic diversity (H) and the Shannon's information index (I) of 0.466 and 0.862, respectively. A UPGMA dendrogram grouped all cultivars into three main clusters. However, two of the most commonly farmed cultivars (DB and BN) from different hatcheries failed to cluster together. Instead, differently named cultivars from the same hatchery tended to group together, implying that their high similarities is partly due to the presence of genetic mixing among cultivars within a hatchery or misuse of cultivar's names. Genetic analysis performed by Bayesian model‐based clustering revealed clear differentiation of three major subgroups (LJ‐202 and LJ‐205; LJ‐C033; XS‐2 and XS‐BN) and one admixed group (the remaining ten cultivars). Our results revealed ambiguous genetic relationships among certain cultivars of S. japonica farmed in northern China. A more stringent and prudent regulation should be applied during breeding and production process in the future.     

Extreme learning machine classification method for lower limb movement recognition

In order to identify the lower limb movements accurately and quickly, a recognition method based on extreme learning machine (ELM) is proposed. The recognizing target set is constructed by decomposing the daily actions into different segments. To get the recognition accuracy of seven movements based on the surface electromyography, the recognition feature vector space is established by integrating short-time statistical characteristics under time domain, and locally linear embedding algorithm is used to reduce the computational complexity and improve robustness of algorithm. Compared with BP, the overall recognition accuracy for each subject in the best dimension with ELM is above 95%.     

Locus Mapping,Molecular Cloning,and Expression Analysis of <Emphasis Type="Italic">rps6kb2</Emphasis>, a Novel Metamorphosis-Related Gene in Chinese Tongue Sole (<Emphasis Type="Italic">Cynoglossus semilaevis</Emphasis>)

Flatfish metamorphosis denotes the extraordinary transformation of a symmetric pelagic larva into an asymmetric benthic juvenile. This unique process involves eye migration, a 90° rotation in posture, and asymmetrical pigmentation for adaptation to a benthic lifestyle. In the present study, we used genetics to map a metamorphosis-related locus (q-10M) in the male linkage group (LG10M), a small interval of 0.9 cM corresponding to a 1.8 M-bp physical area in chromosome 9 in the Chinese tongue sole (Cynoglossus semilaevis). Combined with single-marker analysis, ribosomal protein S6 kinase 2 (rps6kb2) a member of the family of AGC kinases was identified as a novel metamorphosis-related candidate gene. Its expression pattern during metamorphosis was determined by quantitative RT-PCR and whole-mount in situ hybridization analysis. rps6kb2 gene was significantly expressed in metamorphic climax stage larvae and distributed in all the tissues transforming during metamorphosis, including tail, jaw, eye and skin of larvae. The results suggest that rps6kb2 has a general role in tissue transformations during flatfish metamorphosis including tail changes, skull remodeling, eye migration, and asymmetrical pigmentation.     

The septins FaCdc3 and FaCdc12 are required for cytokinesis and affect asexual and sexual development,lipid metabolism and virulence in Fusarium asiaticum

Septins are a highly conserved family of GTP‐binding proteins that contribute to many cellular and metabolic functions, including cell polarity, cytokinesis, cell morphogenesis and pathogenesis. In this study, we characterized the septins FaCdc3 and FaCdc12 in the filamentous fungus Fusarium asiaticum. The functions of FaCdc3 and FaCdc12 were evaluated by constructing deletion mutants of FaCdc3 and FaCdc12, designated ΔFaCdc3‐5 and ΔFaCdc12‐71, respectively. The deletion mutants exhibited a reduced rate of mycelial growth, increased aerial hyphae formation, irregularly shaped hyphae, reduced conidiation and a lack of sexual reproduction in wheat kernels. Histochemical analysis revealed that the conidia and hyphae of ΔFaCdc3‐5 and ΔFaCdc12‐71 formed large lipid droplets (LDs). ΔFaCdc3‐5 and ΔFaCdc12‐71 also exhibited increased resistance to agents that induce osmotic stress and damage the cell membrane and cell wall. In addition, the hyphae and conidia of the two mutants formed fewer septa than those of the wild‐type and exhibited aberrant nuclear distribution. Pathogenicity assays showed that ΔFaCdc3‐5 and ΔFaCdc12‐71 exhibited reduced virulence on wheat spikelets, which was indirectly correlated with a reduced level of deoxynivalenol accumulation. All of these defects were restored by genetic complementation of the two mutants with the parental FaCdc3 and FaCdc12. These results indicate that FaCdc3 and FaCdc12 play a critical role in various cellular processes in F. asiaticum.