Hybridization between Gossypium herbaceum and Gossypium stochsii through embryo rescue

Nutrient media and culture conditions have been defined for ovules 3 and 5 d after pollination and embryos of Gossypium herbaceum respectively.The technique was then used to produce interspecific hybrids between a cultivated Gossypium herbaceum and a wild species,G.stocksii.The hybrid plants were transferred to field and they exhibited most of the characters of the pollen parent i.e.G.stocksii.     

Ovule rescue efficiency of Gossypium hirsutum × G. arboreum progeny from field-grown fruit is affected by media composition and antimicrobial compounds

Upland cotton (Gossypium hirsutum L.) is reproductively isolated from G. arboreum L. via post-zygotic breeding barriers. Literature on somatic embryogenesis of cotton suggests a number of media modifications that might also prove useful for ovule rescue of interspecific crosses. Additionally, endogenous microbes are common in field grown cotton and these potential contaminants must be controlled if interspecific progeny are to be obtained via large-scale field crossing followed by ovule or embryo culture. This study compared nine tissue culture media and two antimicrobial overlay treatments in a factorial design. The overlay treatments were: a 2 ml overlay of 250 mg l⁻¹ cefotaxime, 50 mg l⁻¹ tetracycline HCl, 2.5 mg l⁻¹ amphotericin B, and 50 mg l⁻¹ benomyl applied when the ovules were plated, and no overlay. All of the media in the factorial also contained 250 mg l⁻¹ cefotaxime. Crosses were made in a field at Stoneville, MS between the upland cultivar DeltaPine 90 and the G. arboreum accession A₂-190. Antimicrobial compounds greatly improved the efficiency of obtaining interspecific cotton progenies from field-grown fruit. Germination was not affected by the overlay nor did overlay treatment interact with media. Media significantly affected germination. Of the media studied, the highest frequency of germination was observed for MSB with 1.9 g l⁻¹ additional KNO₃. The addition of 0.5 g l⁻¹ asparagine and 1 g l⁻¹ glutamine did not affect the number of seedlings obtained. A filter paper growing surface or the addition of 0.5 mg l⁻¹ NAA and 0.05 mg l⁻¹ kinetin were disadvantageous.     

Constructing a high-density linkage map for Gossypium hirsutum × Gossypium barbadense and identifying QTLs for lint percentage

To introgress the good fiber quality and yield from Gossypium barbadense into a commercial Upland cotton variety, a high-density simple sequence repeat(SSR) genetic linkage map was developed from a BC1F1 population of Gossypium hirsutum×Gossypium barbadense. The map comprised 2,292 loci and covered 5115.16 centi Morgan(c M) of the cotton AD genome, with an average marker interval of 2.23 c M. Of the marker order for 1,577 common loci on this new map, 90.36% agrees well with the marker order on the D genome sequence genetic map. Compared with five published high-density SSR genetic maps, 53.14% of marker loci were newly discovered in this map. Twenty-six quantitative trait loci(QTLs) for lint percentage(LP) were identified on nine chromosomes. Nine stable or common QTLs could be used for marker-assisted selection. Fifty percent of the QTLs were from G. barbadense and increased LP by 1.07%–2.41%. These results indicated that the map could be used for screening chromosome substitution segments from G. barbadense in the Upland cotton background, identifying QTLs or genes from G. barbadense, and further developing the gene pyramiding effect for improving fiber yield and quality.     

Serological identification and molecular characterization of B (A) 02 subtype in patients and blood donors from Eastern China

This study was designed to identify the rare?type?ABO?blood?groups, B(A) 02, from Eastern China. Three samples with discordant serological results during routine blood type identification and four samples from one sample’ family were selected. All of them were detected by serological method. The exon 6 and 7 of the ABO genes were amplified by PCR and sequenced. They were typed as AsubB by serology and as BO by genotype. In AsubB samples, nt 700C>G mutation was detected in B gene, which was previously defined as B(A)02 alleles. In these seven samples, six showed B(A)02/O01 and one showed B(A)02/O02.B(A)02 allele was found to be more common in this study than B(A)04 which is considered to be more frequent than B(A)02. The careful identification of rare blood types is important for the safety of clinical blood transfusion.     

海岛棉(Gossypium barbadense)DNA的提纯

介绍一种从棉花(Gossypium barbadense)种子中分离天然状、大分子和高纯度DNA的方法。首先,用有机溶剂(醇、醚和酮)抽提除去脂肪、类脂、棉毒素及其它色素,然后,用胰蛋白酶(Trypsin)和去垢剂(SDS)进行处理脱蛋白;最后,用4％珠状琼脂糖凝胶(Sepharose4B Gel)柱层析分离纯化DNA:此方法简便、有效,一般适用于含大量内源多酚类化合物、色素和类脂植物材料中DNA的抽提和纯化。     

Gigantonoclea guizhouensis Gu et Zhi 的叶部解剖研究

一、材料来源和研究方法解剖研究所用的D-1标本是笔者于1984年5月在贵州水城大河边煤矿二采区新开辟的运输巷侧壁砂岩中采到的,其层位经对比与田宝霖和张连武(1980)描述的水城汪家寨矿区综合地层柱中龙潭组下部第8分层的中部砂岩相当。该叶片沉积时受水流冲击,以中脉为对称轴向远轴侧对折成约20°角状(图版Ⅰ,图2)。     

Modeling Proximal Tubule Cell Homeostasis: Tracking Changes in Luminal Flow

During normal kidney function, there are routinely wide swings in proximal tubule fluid flow and proportional changes in Na⁺ reabsorption across tubule epithelial cells. This “glomerulotubular balance” occurs in the absence of any substantial change in cell volume, and is thus a challenge to coordinate luminal membrane solute entry with peritubular membrane solute exit. In this work, linear optimal control theory is applied to generate a configuration of regulated transporters that could achieve this result. A previously developed model of rat proximal tubule epithelium is linearized about a physiologic reference condition; the approximate linear system is recast as a dynamical system; and a Riccati equation is solved to yield the optimal linear feedback that stabilizes Na⁺ flux, cell volume, and cell pH. The first observation is that optimal feedback control is largely consigned to three physiologic variables, cell volume, cell electrical potential, and lateral intercellular hydrostatic pressure. Parameter modulation by cell volume stabilizes cell volume; parameter modulation by electrical potential or interspace pressure act to stabilize Na⁺ flux and cell pH. This feedback control is utilized in a tracking problem, in which reabsorptive Na⁺ flux varies over a factor of two, in order to represent a substantial excursion of glomerulotubular balance. The resulting control parameters consist of two terms, an autonomous term and a feedback term, and both terms include transporters on both luminal and peritubular cell membranes. Overall, the increase in Na⁺ flux is achieved with upregulation of luminal Na⁺/H⁺ exchange and Na⁺–glucose cotransport, with increased peritubular Na⁺–3HCO₃⁻ and K⁺–Cl⁻ cotransport, and with increased Na⁺, K⁺–ATPase activity. The configuration of activated transporters emerges as a testable hypothesis of the molecular basis for glomerulotubular balance. It is suggested that the autonomous control component at each cell membrane could represent the cytoskeletal effects of luminal flow.     

论四射珊瑚的内生长线——以新疆早二叠世 Kepingophyllum aksuense Wu et Zhou 为例

新疆早二叠世 Kepingophyllum aksuense Wu et Zhou的内生长线发育良好,它们是由年季节温度的变化而形成的.据内生长线,可推算出k. aksuense Wu et Zhou的平均生长率为5mm/年.运用珊瑚的生长率及年龄可计算出沉积事件发生的频率.     

In Crystallo Selection to Establish New RNA Crystal Contacts

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Emplectopteridium alatum Kawasaki 的脉序*

Emplectopteridium alatum Kaw. 的脉序历来被描述为叶脉结网并具邻脉,主要基于具有邻脉这一特征,该种被归于美羊齿类.经笔者研究,这种植物没有邻脉而具伴网眼.这样,不但 E. alatum Kaw. 的分类位置需重新考虑,而且所谓 Emplectopteridium 演化系的基础也就完全瓦解.     

Antimicrobial terpenoids of Gossypium: 6-methoxygossypol and 6,6′-dimethoxygossypol

The triterpenoid aldehydes, gossypol (1), 6-methoxygossypol (2) and 6,6′-dimethoxygossypol (3); and the sesquiterpenoid aldehydes, hemigossypol (4) and methoxyhemigossypol (5), were isolated from 1-week-old roots of Gossypium hirsutum and G. barbadense and identified. This is the first report of 2 and 3 in nature and of 4 and 5 from healthy roots. Compounds 2 and 3 also constituted 30% of the total terpenoid aldehydes in the seeds of 1 cultivar of G. barbadense, but occurred only in trace quantities in those of G. hirsutum. Spectral data (UV, IR, NMR, MS) and proof of structure for 2 and 3 are presented.     

Brachyspira asperella Yu et Zhang的个体发育

对Brachyspira asperella Yu et Zhang的40个个体的测量统计表明,此种在生长发育过程中可以区分出3个生长阶段:幼年期壳体生长速度缓慢,壳形卵圆形,胎壳乳突状,壳口圆形;成年期生长迅速,壳高显著大于壳宽的增长率,壳形卵圆形-长卵圆形,壳口卵圆形;老年期生长速度缓慢,壳形长卵圆形,壳饰强烈。这3个生长期代表了此种的个体发育过程。研究化石腹足类种的个体发育过程不仅能了解这一类群的系统发生史、生物演化过程及生物间的亲缘关系,而且能提高物种研究程度,避免分类上的错误。     

论双壳类的 Pteroperna 及其模式种 Pteroperna costatula (Deslongchamps)

翼股蛤(Pteroperna)是 J.Morris 和 J.Lycett 于1853年建立,但该属的分类位置当时并不明确,仅仅在讨论中提到可能为 Pterinea的亚属。Cox(1940)讨论 Pteroperna 时则将其作为翼蛤科(Pteriidae)的属而沿用至今。笔者于1984年在唐古拉山雁石坪地区测制侏罗纪地层剖面时,在同一层位中采集到许多隶属于 Pteroperna costatula 的标本,它们的壳饰特征、壳体形状和英国侏罗纪大鲕状灰岩(Great O(?)lite)中产出的同种标本几无差异。标本大多保存良好,特别是它们的壳层和其围岩在弱酸中可产生差异溶蚀,利用酸蚀法可得到许多暴露出铰系构造和软体印痕的标本,其中有一些反映出个体发育各个阶段的生长特     

The Final Size of an Epidemic and Its Relation to the Basic Reproduction Number

We study the final size equation for an epidemic in a subdivided population with general mixing patterns among subgroups. The equation is determined by a matrix with the same spectrum as the next generation matrix and it exhibits a threshold controlled by the common dominant eigenvalue, the basic reproduction number R₀{\mathcal{R}_{0}}: There is a unique positive solution giving the size of the epidemic if and only if R₀{\mathcal{R}_{0}} exceeds unity. When mixing heterogeneities arise only from variation in contact rates and proportionate mixing, the final size of the epidemic in a heterogeneously mixing population is always smaller than that in a homogeneously mixing population with the same basic reproduction number R₀{\mathcal{R}_{0}}. For other mixing patterns, the relation may be reversed.     

Degeneracy-Driven Self-Structuring Dynamics in Selective Repertoires

Numerous biological interactions, such as interactions between T cell receptors or antibodies with antigens, interactions between enzymes and substrates, or interactions between predators and prey are often not strictly specific. In such less specific, or “sloppy,” systems, referred to here as degenerate systems, a given unit of a diverse resource (antigens, enzymatic substrates, prey) is at risk of being recognized and consumed by multiple consumers (lymphocytes, enzymes, predators). In this study, we model generalized degenerate consumer-resource systems of Lotka–Volterra and Verhulst types. In the degenerate systems of Lotka–Volterra, there is a continuum of types of consumer and resource based on variation of a single trait (characteristic, or preference). The consumers experience competition for a continuum of resource types. This non-local interaction system is modeled with partial differential-integral equations and shows spontaneous self-structuring of the consumer population that depends on the degree of interaction degeneracy between resource and consumer, but does not mirror the distribution of resource. We also show that the classical Verhulst (i.e. logistic) single population model can be generalized to a degenerate model, which shows qualitative behavior similar to that in the degenerate Lotka–Volterra model. These results provide better insight into the dynamics of selective systems in biology, suggesting that adaptation of degenerate repertoires is not a simple “mirroring” of the environment by the “fittest” elements of population.     

β-Glucanases in developing cotton (Gossypium hirsutum L.) fibres

Cotton fibres possess several -glucanase activities which appear to be associated with the cell wall, but which can be partially solubilised in buffers. The main activity detected was that of an exo-(13)--d-glucanase (EC 3.2.1.58) but which also had the characteristics of a -glucosidase (EC 3.2.1.21). Endo-(13)--d-glucanase activity (EC 3.2.1.39) and much lower levels of (14)--d-glucanase activity were also detected. The exo-(13)--glucanase showed a maximum late on (40 days post-anthesis) in the development of the fibres, whereas the endo-(13)--glucanase activity remained constant throughout fibre development. The -glucanase complex associated with the cotton-fibre cell wall also functions as a transglucosylase introducing, inter alia, (16)--glucosyl linkages into the disaccharide cellobiose to give the trisaccharide 4-O--gentiobiosylglucose.Abbreviations CMC carboxymethylcellulose - ONPG o-nitrophenyl--d-glucopyranoside - TLC thin-layer chromatography Presented at the Third Cell Wall Meeting held in Fribourg in 1984