Shell and hinge morphology of juvenile Limopsis (Bivalvia: Arcoida) - implications for limopsid evolution

Early ontogenetic shells of Limopsis angusta, L. aurita, L. cristata, L. friedbergi and L. minuta are described in detail and their morphogenetic traits discussed in a phylogenetic context. Prodissoconch length is found to range from 170-370 µm discounting the so-called prodissoconch 2 stage of authors. Reports of such a stage refer to the early postlarval 'interdissoconch'. Prodissoconch sizes are indicative of lecithotrophy but not of brooding. Limopsid-like prodissoconchs are rather common among pteriomorphs and at present of little use for phylogenetic interpretations, therefore. The early postlarval hinge is characterized by two tooth generations: an early one, (G1), representing the postlarval continuation of provincular teeth, and a late one, (G2), representing the independent adult dentition. This is a plesiomorphic trait for Pteriomorphia. The postlarval ligament is continuous with the larval resilium; it is neither co-functional with nor is it substituted by the typical duplivincular ligament as in other arcoids. Occasionally developed ridges, gutters or multiplication of ligament sublayers remain restricted to the primordial resilifer. It is concluded that the limopsid adult ligament represents a fusion of adult sublayer repetition within a retained larval resilium, a phenomenon best described as a heterochronic process. Comparisons with homologous characters of other arcoids support the view that Limopsidae evolved from parallelodontid arcoids and that they gave rise to Philobryidae but not to Glycymerididae.     

被子植物起源研究中几种观点的思考

对被子植物起源研究中的几种观点进行了讨论。(1)由于被子植物存在着一组共同的性状,它们不可能是从不同祖先起源的,而是有着共同的祖先。被子植物是一个单源起源的类群。现存被子植物分类系统是依据包括形态学(广义)、分子系统学、古植物学和植物地理学等的综合性状建立的,只能表示出现存类群的亲缘关系并且追溯到它们最近的祖先。人们现在还不可能建立一个包括全部已绝灭的类群和现代生存类群的谱系发生系统。因此,现存被子植物分类系统只能看作是“亲缘”系统。(2)分析了用于推测被子植物起源时间的分子、化石和地理分布证据。我们认为,要确定被子植物起源时间,植物化石是一类重要证据,但化石只能说是植物本身可保存部分和当时当地所提供的化石条件的综合反映,它们不可能就是植物类群或种的起源时间。人们还必须考虑到化石本身的演化历史。应用分子钟也是一种手段,但误差比较大。如果我们除了利用上述两种资料之外,根据植物类群的现代分布格局及其形成,把植物的演化同地球的历史和板块运动联系起来,以推断它们起源的时间,这无疑会增加其可信度。通过对56个种子植物不同演化水平的重要科属地理分布的研究结果,我们曾提出被子植物的起源时间可能要追溯到早侏罗世,甚至晚三叠世。(3)分析了基于分子证据所提出的被子植物基部类群——ANITA成员(包括无油樟科Amborellaceae、睡莲科Nymphaeaceae、八角目Illiciales、早落瓣科Trimeniaceae、木兰藤科Austrobaileyaceae)的性质,讨论了ANITA成员在现代几个被子植物分类系统中的系统位置的不同观点,评价了它们的形态学(广义)性状。指出ANITA的成员由于包含大量的祖征,是属于原始的类群。但由于它们的共有衍征很少,如花粉球形,说明它们在被子植物演化早期就分道扬镳了,沿着不同的传代线分化。因此ANITA是一个源于不同传代线的复合群。     

早晚季水稻精米和米皮硒含量的基因型差异研究

选用福建省生产上推广应用的水稻品种(组合)、特种稻和旱稻共45份种质资源为试验材料,在早、晚季分析不同基因型水稻精米和米皮中硒含量的差异.结果表明:①早、晚季水稻品种精米和米皮中硒含量表现均无明显差异.②水稻品种精米和米皮中硒含量分布遵循正态分布规律,表明水稻精米和米皮中硒含量属数量性状.③不同基因型水稻品种精米和米皮中硒含量差异很大,不同品种具有不同的富硒能力.其中早季精米硒含量最高的品种是罗旱紫谷(0.065mg/kg),最低的是84VE303(0.012mg/kg);晚季精米硒含量最高的品种是罗旱紫谷(0.068mg/kg),最低的是加州红米(0.009mg/kg).④早、晚季种植的精米硒含量达0.04 mg/kg以上的水稻品种有:罗旱紫谷、隆化大红欲、555-99、Ziukdo、矮血糯,其中罗旱紫谷精米中硒含量最高,早晚季平均达0.067 mg/kg.     

新疆新陆早系列品种系谱分析与育种方向

通过对新疆新陆早系列品种系谱分析认为,近10年育成品种,产量不断提高,熟性有变晚趋势,抗病性逐步增强,抗枯萎病已基本解决,抗黄萎病有待进一步提高,品质得到改良,但品种类型单一,不能满足我区棉花产业化发展长远要求.因此,需要育种工作者通过拓宽遗传资源、创新种质,结合先进育种方法,并加强抗逆性筛选力度等来选育适合不同要求的棉花新品种.     

Growth and morphological development of sagittal otoliths of larval and early juvenile Trachurus japonicus

The daily periodicity of growth increment formation in sagittal otoliths of jack mackerel Trachurus japonicus was validated by marking otoliths with alizarin complexone (ALC). Analysis of otoliths of known‐age juveniles confirmed that the first increment formed on day 3 after hatching, and was associated with first feeding. A total of 198 specimens, ranging from 2·6 to 49·2 mm in body length (notochord length or standard length) and from 7 to 78 days in age, were collected in the East China Sea and Tosa Bay, and used to examine the association between otolith morphological development and ontogenetic development. The relationship between body length ( L ) and otolith radius ( R ) was significantly described by the linear function L  = 2·65 + 0·0425 R ( n  = 198, r ² = 0·99, P  < 0·001), indicating that somatic growth history can be reconstructed from otolith growth patterns. The otolith was primarily spherical in the preflexion larval stage, and became elongated with notochord flexion. The first secondary primordium formed at c . 25 days, during the middle postflexion stage, and was associated with metamorphosis. By c . 42 days the sagittal otolith was adult‐like in morphology, with the primary growth zone enclosed by the marginal growth zone, except in the anterior rostrum area. Thus age, growth and developmental stages were recorded in sagittal otoliths during the larval and early juvenile stages of jack mackerel.     

浙江天童枫香树群落不同垂直层次物种间的联结性与相关性

种间关系是植物群落重要的数量和结构特征之一, 分析群落不同垂直层次物种的种间联结和相关性对于理解群落结构、动态和分类等具有重要的生态意义。该研究选取浙江省天童处于演替前期的枫香树(Liquidambar formosana)群落乔木层3个物种、亚乔木层3个物种以及灌木层28个物种为研究对象, 应用基于二元数据的方差比率法、χ²统计量检验和基于数量数据的Spearman秩相关系数检验研究了3个垂直层次间物种的联结性与相关性。结果发现: (1)乔木层与亚乔木层物种总体间存在不显著正联结, 乔木层与亚乔木层主要物种间相互独立的种对较多, 较少种对显著联结或相关; (2)乔木层与灌木层物种总体显著正联结, 显著关联或相关的种对较多, 种对间依赖性较强; (3)亚乔木层与灌木层物种总体同样存在显著正联结, 种对间关系较为紧密。该研究结果表明: 群落垂直层次间物种生态习性和对生境适应的趋同性, 以及在垂直方向上对生境要求的互补性差异是决定演替前期种对关系的主要因素。     

Real‐time endoscopic Raman spectroscopy for in vivo early lung cancer detection

Currently the most sensitive method for localizing lung cancers in central airways is autofluorescence bronchoscopy (AFB) in combination with white light bronchoscopy (WLB). The diagnostic accuracy of WLB + AFB for high grade dysplasia (HGD) and carcinoma in situ is variable depending on physician's experience. When WLB + AFB are operated at high diagnostic sensitivity, the associated diagnostic specificity is low. Raman spectroscopy probes molecular vibrations and gives highly specific, fingerprint‐like spectral features and has high accuracy for tissue pathology classification. In this study we present the use of a real‐time endoscopy Raman spectroscopy system to improve the specificity. A spectrum is acquired within 1 second and clinical data are obtained from 280 tissue sites (72 HGDs/malignant lesions, 208 benign lesions/normal sites) in 80 patients. Using multivariate analyses and waveband selection methods on the Raman spectra, we have demonstrated that HGD and malignant lung lesions can be detected with high sensitivity (90%) and good specificity (65%).

     

Impact of early personal‐history characteristics on the Pace of Aging: implications for clinical trials of therapies to slow aging and extend healthspan

Therapies to extend healthspan are poised to move from laboratory animal models to human clinical trials. Translation from mouse to human will entail challenges, among them the multifactorial heterogeneity of human aging. To inform clinical trials about this heterogeneity, we report how humans’ pace of biological aging relates to personal‐history characteristics. Because geroprotective therapies must be delivered by midlife to prevent age‐related disease onset, we studied young‐adult members of the Dunedin Study 1972–73 birth cohort (n = 954). Cohort members’ Pace of Aging was measured as coordinated decline in the integrity of multiple organ systems, by quantifying rate of decline across repeated measurements of 18 biomarkers assayed when cohort members were ages 26, 32, and 38 years. The childhood personal‐history characteristics studied were known predictors of age‐related disease and mortality, and were measured prospectively during childhood. Personal‐history characteristics of familial longevity, childhood social class, adverse childhood experiences, and childhood health, intelligence, and self‐control all predicted differences in cohort members’ adulthood Pace of Aging. Accumulation of more personal‐history risks predicted faster Pace of Aging. Because trials of anti‐aging therapies will need to ascertain personal histories retrospectively, we replicated results using cohort members’ retrospective personal‐history reports made in adulthood. Because many trials recruit participants from clinical settings, we replicated results in the cohort subset who had recent health system contact according to electronic medical records. Quick, inexpensive measures of trial participants’ early personal histories can enable clinical trials to study who volunteers for trials, who adheres to treatment, and who responds to anti‐aging therapies.