Cohort analysis on a freshwater fish Osteochilus hasselti C. & V. (Cyprinidae) at Bukit Merah Reservoir,Malaysia     

Yap Siaw-Yang 《Fisheries Research》1984,2(4):299-314

An earlier cohort analysis using catch-at-length data (for the period May 1979–April 1980) on the stock of Osteochilus hasselti C. & V. computes statistics on: (1) the total stock at the start of the cohort (N = 22.7 × 10⁵) (these stock numbers decrease progressively at successive lengths, in a steady state and assuming constant natural mortality rate, M = 2.1); (2) catch numbers in a cohort totalling 780 940 individuals; (3) the exploitation rate of the cohort of E = 0.34, suggesting moderate exploitation of the species at Bukit Merah Reservoir, Malaysia.However, the validity of cohort analysis on a species exploited at a very early age depends on the input value of the variables natural mortality rate (M), fishing mortality rate of terminal largest fish (F_ter), and growth parameters (L_∞, K). Because of the methodological difficulties in estimation and verification of M, F_ter and K values of O. hasselti, a range of values of input variables is adopted for comparison. The effect of the variability of M values (0.5, 1.0, 1.5 and 2.5) on the computation results of smaller size-class fishes N_L is significantly different from that based on M = 2.1, showing a much lower population size.The variability of input values of F_ter (range 0.5–2.5) and K (0.28–2.62) is tested on their effects on the population size of recruits. The combined effect of M and K in the relationship of $\text{M}\text{K}$ ranging from 0.8 to 2.5 is varied to decide the possible values of K. In general, the different input values of M, F_ter and K result in lower estimates of the population size of recruits, N_r This is about 28% lower than N_r = 22.7 × 10⁵ when M = F_ter = 2.1 and K = 1.15. With an inherent computational bias, the population size of N_r = 22.7 × 10⁵ is probably an under-estimate, but it is both reasonable and biologically possible for O. hasselti at Bukit Merah Reservoir, Malaysia, since the input variables are generated from representative length composition data of commercial catches and tagging data.  相似文献   

Characterisation of taro (Colocasia esculenta (L.) Schott) genetic resources in Southeast Asia and Oceania     

V. Lebot  M.S. Prana  N. Kreike  H. van Heck  J. Pardales  T. Okpul  T. Gendua  M. Thongjiem  H. Hue  N. Viet  T.C. Yap 《Genetic Resources and Crop Evolution》2004,51(4):381-392

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Multiplex PCR genotyping for five bacterial blight resistance genes applied to marker‐assisted selection in rice (Oryza sativa)          下载免费PDF全文

Ruishen Yap  Yu‐Chia Hsu  Yong‐Pei Wu  Yann‐Rong Lin  Chei‐Wei Kuo 《Plant Breeding》2016,135(3):309-317

Bacterial blight (BB) is the most economically damaging disease of rice in Asia and other parts of the world. In this study, a multiplex PCR genotyping method was developed to simultaneously identify genotypes of five BB resistance genes, Xa4, xa5, Xa7, xa13 and Xa21. The resistance R alleles were amplified using five functional markers (FMs) to generate amplicons of 217, 103, 179, 381 and 595 bp in IRBB66. Amplicons of 198, 107, 87, 391 and 467 bp corresponded to susceptible alleles in Taiwanese japonica rice cultivars. In backcross breeding programmes, the multiplex PCR assay was integrated into selection from a population using BB resistance donor IRBB66 crossed to rice cultivar ‘Tainung82’. Two plants with homozygosity for Xa4, xa5, Xa7, xa13 and Xa21 were selected from 1100 BC₂F₂ plants. In addition, the five BB resistance genes were also accurately identified in F₂ populations. This multiplex PCR method provides a rapid and efficient method for detecting various BB resistance genes, which will assist in pyramiding genes to improve durability of BB resistance in Taiwanese elite rice cultivars.  相似文献   

Development of new assessment methods for Acropora coral recruitment using coral settlement devices and holes of marine block     

Kakaskasen Andreas Roeroe  Minlee Yap  Mineo Okamoto 《Fisheries Science》2013,79(4):617-627

We developed new assessment methods for Acropora coral recruitment using coral settlement devices (CSDs) and holes of a marine block. Both devices were deployed in situ before mass spawning of Acropora corals. The CSDs were sampled after 3–4 months of spawning to measure early recruitment, whereas holes of the marine block were observed underwater or MB was sampled to observe holes after 1 year of spawning to measure the recruitment. By combining the results, we would know the recruitment (visually identified underwater) in reefs, including the amount of early recruitment (identified by stereomicroscopic methods), and the environmental condition of the coral reef. These results would help to predict the future of a reef. Nagura Bay had a high early Acropora recruitment; however, due to competition with algae and sedimentation, the recruitment of juvenile corals was extremely low. The reef would possibly be healthy and sustainable at sites where both the early recruitment and recruitment are high. However, if both are low, the reef will be in a critical condition where urgent restoration will be required.  相似文献   

Impact of vitronectin concentration and surface properties on the stable propagation of human embryonic stem cells     

Li J  Bardy J  Yap LY  Chen A  Nurcombe V  Cool SM  Oh SK  Birch WR 《Biointerphases》2010,5(3):FA132-FA142

The standard method for culturing human embryonic stem cells (hESC) uses supporting feeder layers of cells or an undefined substrate, Matrigel(?), which is a basement membrane extracted from murine sarcoma. For stem cell therapeutic applications, a superior alternative would be a defined, artificial surface that is based on immobilized human plasma vitronectin (VN), which is an adhesion-mediating protein. Therefore, VN adsorbed to diverse polymer surfaces was explored for the continuous propagation of hESC. Cells propagated on VN-coated tissue culture polystyrene (TCPS) are karyotypically normal after >10 passages of continuous culture, and are able to differentiate into embryoid bodies containing all three germ layers. Expansion rates and pluripotent marker expression verified that a minimal VN surface density threshold is required on TCPS. Further exploration of adsorbed VN was conducted on polymer substrates with different properties, ranging from hydrophilic to hydrophobic and including cationic and anionic polyelectrolyte coatings. Despite differing surface properties, these substrates adsorbed VN above the required surface density threshold and were capable of supporting hESC expansion for >10 passages. Correlating wettability of the VN-coated surfaces with the response of cultured hESC, higher cell expansion rates and OCT-4 expression levels were found for VN-coated TCPS, which exhibits a water contact angle close to 65°. Importantly, this simple, defined surface matches the performance of the benchmark Matrigel, which is a hydrogel with highly complex composition.  相似文献   

野生马蹄金种质资源的RAPD鉴别   总被引：1，自引：1，他引：0  

付薇  唐成斌  吴佳海  王小利  干友民  张建波  陈伟 《草业科学》2010,27(4):106-111

采用RAPD分子标记技术,从100个随机引物中筛选出多态性强、重复性好且稳定性高的引物22个,对西南区16份抗性较强、坪用价值较高的马蹄金Dichondra repens材料进行扩增,共扩增出269条带,其中多态性带246条,多态性比率为91.45%,表明野生马蹄金植物种间有丰富的遗传多态性。采用UPGMA法聚类分析,在遗传距离0.73处把马蹄金材料分为4类,部分地理上相近的马蹄金种质资源被聚在了不同的大类中,分类结果能将优异马蹄金材料区分开来,与景观价值评定较吻合。  相似文献   

柞蚕杂种优势的研究与利用   总被引：1，自引：0，他引：1  

朱有敏  李青峰  孟宪友  仝振祥  王凤成  冀万杰 《蚕业科学》2011,37(2):292-295

我国自20世纪70年代开始系统开展柞蚕杂种优势的研究,从柞蚕不同经济性状的杂种优势分析,到通过重要生化酶指标预测主要经济性状的杂种优势表现,为柞蚕优良新品种选育奠定了理论基础。依据对交亲本的亲缘关系、遗传特性、主要性状表现,采用二元、三元或多元杂交形式组配的柞蚕优良杂交组合,使生产上推广的柞蚕新品种较大程度地发挥了增产增收作用,生产上柞蚕杂交种的普及率已达到90%以上。今后应充分利用现代分子生物学技术手段,加强柞蚕重要经济性状的遗传规律研究及育种材料的创新,提高杂种优势的利用率;针对柞蚕杂交组合的特殊性,在生产上采用合理的放养利用模式,并严格按杂交形式繁育优势杂交组合的对交品种,保证生产用杂交种的品质。  相似文献   

Bioactive Compounds from Marine Sponges: Fundamentals and Applications     

Disha Varijakzhan  Jiun-Yan Loh  Wai-Sum Yap  Khatijah Yusoff  Rabiha Seboussi  Swee-Hua Erin Lim  Kok-Song Lai  Chou-Min Chong 《Marine drugs》2021,19(5)

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.  相似文献   

Identifying climate refugia for 30 Australian rainforest plant species,from the last glacial maximum to 2070     

Das  Sourav  Baumgartner  John B.  Esperon-Rodriguez  Manuel  Wilson  Peter D.  Yap  Jia-Yee S.  Rossetto  Maurizio  Beaumont  Linda J. 《Landscape Ecology》2019,34(12):2883-2896

Landscape Ecology - Climate refugia—areas that remain suitable for species during periods of climate disruption—have played an important role in species persistence over time....  相似文献   

Critical but Constructive Comments on a Paper by Hadibrata et al. (2012) (DOI 10.1007/s11270-012-1095-7) Published in Water, Air, and Soil Pollution     

C. K. Yap 《Water, air, and soil pollution》2012,223(9):5803-5805

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