大别山北坡落叶阔叶林种间相关的研究

应用联结系数AC,点相关系数PCC,x~2检验和pearson相关系数r公式测定了大别山北坡落叶阔叶林的种间关系,依据种间联结程度将乔木层划分出3个生态种组,即栓皮栎──枫香种组,化香──短柄抱种组和锐齿栎──灯台树种组。     

“秦油2号”油菜植株内含物与萝卜蚜有翅率的关系

通过对Ｎ、Ｐ、Ｋ不同施肥条件下的“秦油２号”油菜植株内含物等与萝卜蚜有翅率关系的研究,建立了８个数学模型,结果表明可溶性糖、总Ｎ、糖与蛋白质之比和丝氨酸与萝卜蚜有翅率有密切关系,其次是天门冬氨酸、苏氨酸、谷氨酸、甘氨酸、丙氨酸、蛋氨酸、异亮氨酸、亮氨酸、酪氨酸、含水量、水溶性蛋白、酰胺氮和含Ｐ量等．     

The effect of hydration on the dynamics of trimethoprim bound to dihydrofolate reductase. A deuterium NMR study.

To determine the effect of hydration on the dynamics of a protein complex, we used deuterium nuclear magnetic resonance (NMR) techniques to examine a trimethoprim (TMP)/E. coli dihydrofolate reductase (DHFR) complex in its lyophilized, partially hydrated, polycrystalline, and ammonium sulfate-precipitated states. The results indicate that TMP is rigid in the lyophilized powder state. The dynamic behavior could be restored by partial rehydration. At 30 wt% hydration the deuterium spectrum of the partially hydrated sample was indistinguishable from that of the polycrystalline and ammonium sulfate-precipitated samples, suggesting that the structure of the protein/TMP complex is similar in the three physical states. Furthermore, we found that the para- and meta-methoxyl groups have very different dynamical behavior.     

东方蝾螈繁殖生态的研究

本文报道东方蝾螈(Cynops orientalis)的繁殖生态,内容有精巢分叶、精子形态、怀卵量、性征、性比、求偶、交配、纳精、产卵及孵化等,并对产卵场中性比的周年变化、精包形态、精子存活力及与蓝尾蝾螈的种间差异进行了观察和讨论。     

Genetic transfer and expression of reconstructed yeast artificial chromosomes containing normal and translocated BCL2 proto-oncogenes.

The goal of this study was to determine whether it will be feasible to study the expression of a large, human gene, such as the BCL2 proto-oncogene, by DNA transfection. The BCL2 proto-oncogene is 230 kb in size and is deregulated in tumor cells by translocation into the immunoglobulin heavy-chain locus. Yeast artificial chromosomes (YACs) containing the human BCL2 gene were altered by homologous recombination in Saccharomyces cerevisiae to yield replicas of the normal and translocated alleles. Constructions containing either allele and ranging in size from 360 to 800 kb were integrated stably into a mouse tumor line. Fifty-eight percent of the clones contained a copy of the entire YAC insert. Over 50% of these clones expressed appropriate levels of human BCL2 RNA and protein. These studies suggested that the expression of large human genes and their pathologic rearrangements can be studied by transfection techniques employing YACs propagated in S. cerevisiae.     

Structural and dynamic studies of a non-self-complementary dodecamer DNA duplex.

A non-self-complementary dodecamer duplex d(CCTAAATTTGCC).d(GGCAAATTTAGG) has been investigated in solution by high resolution 1H NMR. Almost complete resonance assignment of both non-exchangeable and exchangeable protons, has been achieved. The duplex is essentially B-type, with distortions apparent at the AT and TA steps. These distortions and their affects on dynamics have been probed by the measurement of base-pair lifetimes, and observation of water of hydration. Base-pair opening rates were derived from measurements of T1's and effects on linewidths of the T and G imino protons on addition of an exchange catalyst. Our results are generally in line with observations reported for other systems, but we see only a slight drop in the A.T base-pair lifetime on moving out from the central region. This observation is reinforced by the detection of DNA-water nOe's for residues distributed throughout the dodecamer sequence.     

在中国壮族家系中发现的一例-α~T/-α~Q复合β~0β~0珠蛋白基因型

本文报道在我国广西隆林壮族中发现一个罕見的HbQ复合α,β地中海贫血家系。先证者女,18岁,贫血面容,肝脾肿大。化学结构分析确证本Hb变异体为HbQ Thailand[α74(EF3)Asp→His]。血红蛋白组成以及α和β珠蛋白基因分析结果表明,先证者的珠蛋白基因型为-α~Q/-α~T复合β°/β°(IVSI-1G→T/Codon17A→T);先证者父的基因型为-‘α~Q/-复合β~O/β~A(IVSI-1G→T/β~A);先证母的基因型为-α~T/αα复合β~O/β~A(Codon17A→T/β~A)。     

The detection and attribution of extreme reductions in vegetation growth across the global land surface

Negative extreme anomalies in vegetation growth (NEGs) usually indicate severely impaired ecosystem services. These NEGs can result from diverse natural and anthropogenic causes, especially climate extremes (CEs). However, the relationship between NEGs and many types of CEs remains largely unknown at regional and global scales. Here, with satellite-derived vegetation index data and supporting tree-ring chronologies, we identify periods of NEGs from 1981 to 2015 across the global land surface. We find 70% of these NEGs are attributable to five types of CEs and their combinations, with compound CEs generally more detrimental than individual ones. More importantly, we find that dominant CEs for NEGs vary by biome and region. Specifically, cold and/or wet extremes dominate NEGs in temperate mountains and high latitudes, whereas soil drought and related compound extremes are primarily responsible for NEGs in wet tropical, arid and semi-arid regions. Key characteristics (e.g., the frequency, intensity and duration of CEs, and the vulnerability of vegetation) that determine the dominance of CEs are also region- and biome-dependent. For example, in the wet tropics, dominant individual CEs have both higher intensity and longer duration than non-dominant ones. However, in the dry tropics and some temperate regions, a longer CE duration is more important than higher intensity. Our work provides the first global accounting of the attribution of NEGs to diverse climatic extremes. Our analysis has important implications for developing climate-specific disaster prevention and mitigation plans among different regions of the globe in a changing climate.     

Accelerated organic matter decomposition in thermokarst lakes upon carbon and phosphorus inputs

Mineralization of dissolved organic matter (DOM) in thermokarst lakes plays a non-negligible role in the permafrost carbon (C) cycle, but remains poorly understood due to its complex interactions with external C and nutrient inputs (i.e., aquatic priming and nutrient effects). Based on large-scale lake sampling and laboratory incubations, in combination with ¹³C-stable-isotope labeling, optical spectroscopy, and high-throughput sequencing, we examined large-scale patterns and dominant drivers of priming and nutrient effects of DOM biodegradation across 30 thermokarst lakes along a 1100-km transect on the Tibetan Plateau. We observed that labile C and phosphorus (P) rather than nitrogen (N) inputs stimulated DOM biodegradation, with the priming and P effects being 172% and 451% over unamended control, respectively. We also detected significant interactive effects of labile C and nutrient supply on DOM biodegradation, with the combined labile C and nutrient additions inducing stronger microbial mineralization than C or nutrient treatment alone, illustrating that microbial activity in alpine thermokarst lakes is co-limited by both C and nutrients. We further found that the aquatic priming was mainly driven by DOM quality, with the priming intensity increasing with DOM recalcitrance, reflecting the limitation of external C as energy sources for microbial activity. Greater priming intensity was also associated with higher community-level ribosomal RNA gene operon (rrn) copy number and bacterial diversity as well as increased background soluble reactive P concentration. In contrast, the P effect decreased with DOM recalcitrance as well as with background soluble reactive P and ammonium concentrations, revealing the declining importance of P availability in mediating DOM biodegradation with enhanced C limitation but reduced nutrient limitation. Overall, the stimulation of external C and P inputs on DOM biodegradation in thermokarst lakes would amplify C-climate feedback in this alpine permafrost region.     

赤子爱胜蚯蚓(Eisenia Foetida)纤溶酶的研究,Ⅳ纤溶酶组成成分的分子量测定

本文报告了用SephadexG—100柱层析法纯化样品和聚丙烯酰胺凝胶电泳测定纤溶酶组成成分的分子量的研究结果。经柱层析分离的纤溶酶电泳测定分子量结果为11条带,分别为68,000、49,000、42,000、41,000、36,000、29,000、27,000、26,000、25,000、21,000和12,000。而纤溶酶的主要组分集中在21.000与42.000之间,为其活性组分。