长吻鮠精巢发育的分期及精子的发生和形成

长吻鮠精巢的发育分为精原细胞增殖期、精母细胞生长期、精母细胞成熟期、精子细胞出现期,精子完全成熟期和精子退化吸收期。精巢的后1/3不产生也不贮存精子,精子的发生和形成经过精原细胞、精母细胞、精子细胞到精子的一系列过程。精原细胞有两种类型。精子无顶体,有中心粒帽,中片长,核凹窝和线粒体发达,鞭毛具侧鳍。     

A Review on Additives for Halide Perovskite Solar Cells

Additives are widely adopted for efficient, stable, and hysteresis‐free perovskite solar cells and play an important role in various breakthroughs of perovskite solar cells (PSCs). Herein the various additives adopted for PSCs are reviewed and their functioning mechanism and influence on device performance is described. The main roles of additives, modulating morphology of perovskite films, stabilizing phase of formamidinium (FA) and cesium (Cs)‐based perovskites, adjusting energy level alignment in PSCs, suppressing nonradiative recombination in perovskites, eliminating hysteresis, enhancing operational stability of PSCs, are summarized.     

椭圆背角无齿蚌贝壳棱柱层的结构

用光学显微镜和扫描电子显微镜对椭圆背角无齿蚌Anadonta woodiana elliptica贝壳的横截面、纵截面和水平截面进行了观测。结果表明,边长为10～50μm、高度为35～47μm的多边棱柱体是贝壳棱柱层结构的基本单元。它们在贝壳的水平轴和横轴的二维空间方向逐步进行堆砌,以形成棱柱层。在堆砌时所形成的夹角,导致了贝壳在横轴和纵轴方向形成一定的弧度。在外套膜分泌形成贝壳的过程中,依次形成角质层、棱柱层、珍珠层。     

Pedigree‐based analysis of derivation of genome segments of an elite rice reveals key regions during its breeding

Analyses of genome variations with high‐throughput assays have improved our understanding of genetic basis of crop domestication and identified the selected genome regions, but little is known about that of modern breeding, which has limited the usefulness of massive elite cultivars in further breeding. Here we deploy pedigree‐based analysis of an elite rice, Huanghuazhan, to exploit key genome regions during its breeding. The cultivars in the pedigree were resequenced with 7.6× depth on average, and 2.1 million high‐quality single nucleotide polymorphisms (SNPs) were obtained. Tracing the derivation of genome blocks with pedigree and information on SNPs revealed the chromosomal recombination during breeding, which showed that 26.22% of Huanghuazhan genome are strictly conserved key regions. These major effect regions were further supported by a QTL mapping of 260 recombinant inbred lines derived from the cross of Huanghuazhan and a very dissimilar cultivar, Shuanggui 36, and by the genome profile of eight cultivars and 36 elite lines derived from Huanghuazhan. Hitting these regions with the cloned genes revealed they include numbers of key genes, which were then applied to demonstrate how Huanghuazhan were bred after 30 years of effort and to dissect the deficiency of artificial selection. We concluded the regions are helpful to the further breeding based on this pedigree and performing breeding by design. Our study provides genetic dissection of modern rice breeding and sheds new light on how to perform genomewide breeding by design.     

The Inner Nuclear Membrane Protein Bqt4 in Fission Yeast Contains a DNA-Binding Domain Essential for Telomere Association with the Nuclear Envelope

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The complete mitochondrial genome of Chinese rare minnow, Gobiocypris rarus (Teleostei: Cypriniformes)

The Chinese rare minnow, Gobiocypris rarus, which is endemic to China, is an attractive aquatic laboratory animal in China. In the present study, the complete mitogenome sequence of G. rarus has been determined using long polymerase chain reaction (PCR) method. It was 16,601 bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region, the gene composition and order of which are similar to most other vertebrates. Except for eight tRNA and ND6 genes, all other mitochondrial genes are encoded on the heavy strand. The overall base composition of the heavy strand is 29.5% A, 27.6% T, 25.7% C, and 17.2% G, with a slight AT bias of 57.1%. There are 10 regions of gene overlap totaling 27 bp and 13 intergenic spacer regions totaling 63 bp. The mitogenome sequence of G. rarus could contribute to a better solution of its phylogenetic position within cyprinid fishes based on the whole mitogenomic data.     

短尾拟鲿分类地位的探讨

短尾拟鲿PSEUDOBAGRUS BREVICAUDATUS(Wu)原名短(鱼危)Leiocassis brevicaudatus Wu是伍献文先生1930年命名的一个新种1。张春霖先生在《中国贴类志》中将其改称为短尾黄颖鱼PSEUDOBAGRUS BREVICAUDATUS2。湖北省水生生物研究所在《长江鱼类》一书中仍称为短尾跪2,并有较细致的形态描述。成庆泰先生等主要依据脂鳍长短和尾鳍之中央鳍条至少为最长鳍条的2/3等特征,将其归人拟偿属,称短尾拟绘4。1990-1993年,我们在进行嘉陵江绘科鱼类骨骼的比较研究中,发现短尾拟嵘骨骼的许多特征与跪属的粗唇(鱼危)Leiocassis crassilabris GUnther等相似,而与拟鳄属的细体拟偿Pseudobagrus pratti (GUnther)、切尾拟(鱼危)Pseudobagrus truncatus (Regan)和乌苏拟(鱼危)Pseudobagrus ussuriensis(Dybowski)等差异明显。       

长吻鮠的卵巢发育和周年变化及繁殖习性研究

本文报道了长吻卵巢发育与周年变化特点和繁殖习性。依外形和组织学特征,性成熟前至性成熟鱼卵巢的发育可分为卵原细胞期、单层滤泡期、卵黄泡期,卵黄充满期、成熟期和退化期６个时期,Ⅰ期性腺只存在于１龄内个体,Ⅱ期性腺持续２年左右,性成熟前发育至Ⅲ期,经Ⅳ、Ⅴ期发育至成熟并首次参与繁殖,最小性成熟个体３龄。性成熟后个体卵巢的发育只有后５个时期。繁殖期４—６月,产后卵巢很快退回到Ⅱ期,Ⅲ期卵巢越冬。一次产卵类型。卵壳膜源于滤泡细胞。卵粒的退化吸收分５步完成。