Stepwise and large-magnitude negative shift in δ13Ccarb preceded the main marine mass extinction of the Permian–Triassic crisis interval

Large perturbations to the global carbon cycle occurred during the Permian–Triassic boundary mass extinction, the largest extinction event of the Phanerozoic Eon (542 Ma to present). Controversy concerning the pattern and mechanism of variations in the marine carbonate carbon isotope record of the Permian–Triassic crisis interval (PTCI) and their relationship to the marine mass extinction has not been resolved to date. Herein, high-resolution carbonate carbon isotope profiles (δ¹³C_carb), accompanied by lithofacies, were generated for four sections with microbialite (Taiping, Zuodeng, Cili, and Chongyang) in South China to better constrain patterns and controls on δ¹³C_carb variation in the PTCI and to test hypotheses about the temporal relationship between perturbations to the global carbon cycle and the marine mass extinction event. All four study sections exhibit a stepwise negative shift in δ¹³C_carb during the Late Permian–Early Triassic, with the shift preceding the end-Permian crisis being larger (> 3‰) than that following it (1–2‰). The pre-crisis shifts in δ¹³C_carb are widely correlatable and, hence, represent perturbations to the global carbon cycle. The comparatively smaller shifts following the crisis demonstrate that the marine mass extinction event itself had at most limited influence on the global carbon cycle, and that both Late Permian δ¹³C_carb shifts and the mass extinction must be attributed to some other cause. Their origin cannot be uniquely determined from C-isotopic data alone but appears to be most compatible with a mechanism based on episodic volcanism in combination with collapse of terrestrial ecosystems and soil erosion.     

Pulmonary Tuberculosis Incidence and Risk Factors in Rural Areas of China: A Cohort Study

The incidence of tuberculosis (TB) and its risk factors in China remains unclear. This study examined TB incidence and relative risk factors in rural areas of China. Participants (n = 177,529) were recruited in Xiangtan County (in the central area of China) and in Danyang County (in the eastern area of China) in 2009 and a followed-up study was conducted for one year. The incidence density of pulmonary TB and smear-positive TB were 91.6 (95% CI: 78.7, 106.0) per 100,000 person-year and 36.7 (95% CI: 33.1, 52.4) per 100,000 person-year respectively in Xiangtan, and 47.3 (95% CI: 38.2, 57.5) per 100,000 person-year and 22.7 (95% CI: 16.5, 30.8) per 100,000 person-year in Danyang. The medical history of TB was associated with TB, with the relative risk (RR) of 7.00 (95% CI: 2.76, 17.18) in Xiangtan and that of 31.08 (95% CI: 13.22, 73.10) in Danyang. The association between TB and per capita living space over median was found in Xiangtan, with the RR of 1.86 (95% CI: 1.15, 3.01). No association was found between TB and the insurance status, the contact history with TB, the history of diabetes, smoking, or per capita annual income. The host genetic susceptibility, and social factors such as education and income could be considered in future studies.     

三角帆蚌Hc-GSK3β基因鉴定及内壳色性状相关SNP筛选

为了探究三角帆蚌(Hyriopsis cumingii)糖原合成激酶-3β(GSK3β)基因对壳色的影响,研究采用RACE技术获得Hc-GSK3β基因cDNA全长1867 bp,其中包含1261 bp的ORF区编码420个氨基酸, ORF中含有一个S＿TKc结构域,该结构域序列高度保守。组织差异表达分析发现Hc-GSK3β基因在紫色蚌鳃、斧足、内脏团和边缘膜组织中表达量高于白色蚌的表达量(P<0.05),且在斧足和边缘膜表达差异水平达到极显著(P<0.01),而在紫色蚌闭壳肌组织中表达量显著低于白色蚌(P<0.05)。原位杂交(ISH)实验结果显示在三角帆蚌外套膜的外褶、中褶、內褶、背膜区和腹膜区均有阳性信号产生,且在外褶的信号表达较强烈。该基因经重测序比较,共鉴定出6个SNP位点,其中在C+185A位点的CA基因型在紫色蚌的分布频率显著高于白色三角帆蚌(P<0.05);在紫色蚌中, T+341G位点TT基因型三角帆蚌内壳颜色参数b值显著低于TG基因型(P<0.05)。研究表明, Hc-GSK3β基因参与了三角帆蚌壳色形成,筛选的SNP标记可用于三角帆蚌壳...     

用地高辛标记探针检测基因工程人β干扰素制品中的外源DNA

基因工程人β干扰素工程菌经发酵培养、纯化后获得纯的制品,采用斑点杂交技术,用非放射性地高辛标记超声裂解的全工程菌ＤＮＡ作为探针,检测基因工程人β干扰素纯品,结果显示：基因工程人β干扰素纯品中的外源ＤＮＡ含量小于１００ｐｇ／剂。     

Spectroscopic characterization and molecular weight distribution of dissolved organic matter in sediment porewaters from Lake Erhai, Southwest China

Dissolved organic matter (DOM) in sediment porewaters from Lake Erhai, Southwest China was investigated using dissolved organic carbon (DOC) concentration, UV absorbance, fluorescence and molecular weight distribution. DOC exhibited a high concentration at the sediment–water interface with a rapid decrease to the oxic–anoxic interface at approximately 7 cm, and then increased with depth. Similar trends were also found for the UV absorption coefficients at 254 and 280 nm in the porewaters. DNA in the sediment was also measured, which confirmed the high abundance of aerobic bacteria in the upper layer of the sediment. Both humic-like (peaks A and C) and protein-like (peaks B and D) fluorescence were observed in the porewater DOM, and their fluorescence intensities exhibited a similar porewater profile as DOC concentration. A strong correlation was found between the peak fluorescence intensity ratio r(A, C) and r(D, B). Both the fluorescence index and UV absorption coefficient at 254 nm suggested a dramatic increase in aromaticity of porewater DOM across the oxic–anoxic interface. Porewater DOM exhibited a multimodal distribution of molecular weight with a relatively low polydispersity. The results of this study offer significant insight into the nature and properties of DOM in freshwater ecosystems.     

Partial Protective Effect of Intranasal Immunization with Recombinant Toxoplasma gondii Rhoptry Protein 17 against Toxoplasmosis in Mice

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite that infects a variety of mammals, including humans. An effective vaccine for this parasite is therefore needed. In this study, RH strain T. gondii rhoptry protein 17 was expressed in bacteria as a fusion with glutathione S-transferase (GST) and the recombinant proteins (rTgROP17) were purified via GST-affinity chromatography. BALB/c mice were nasally immunised with rTgROP17, and induction of immune responses and protection against chronic and lethal T. gondii infections were investigated. The results revealed that mice immunised with rTgROP17 produced high levels of specific anti-rTgROP17 IgGs and a mixed IgG1/IgG2a response of IgG2a predominance. The systemic immune response was associated with increased production of Th1 (IFN-γand IL-2) and Th2 (IL-4) cytokines, and enhanced lymphoproliferation (stimulation index, SI) in the mice immunised with rTgROP17. Strong mucosal immune responses with increased secretion of TgROP17-specific secretory IgA (SIgA) in nasal, vaginal and intestinal washes were also observed in these mice. The vaccinated mice displayed apparent protection against chronic RH strain infection as evidenced by their lower liver and brain parasite burdens (59.17% and 49.08%, respectively) than those of the controls. The vaccinated mice also exhibited significant protection against lethal infection of the virulent RH strain (survival increased by 50%) compared to the controls. Our data demonstrate that rTgROP17 can trigger strong systemic and mucosal immune responses against T. gondii and that ROP17 is a promising candidate vaccine for toxoplasmosis.     

中国多孔菌科一新记录属——棘刚毛菌属(Echinochaete)

笔者1987年9月8日在吉林省张广才岭老爷岭山采到一份标本,生于阔叶树腐木上,经鉴定为短孔棘刚毛菌(Echinochaete brachyporus)隶属于多孔菌科(Polyporaceae),棘刚毛菌属(Echinochaete)。棘刚毛菌属为多孔菌科中一个较小的属,现已见报道的共有6种1变种,分布于世界许多地区。对于本属及其种类在我国未曾有记载。本文对该属的概况及新记录种的特征、分布作了报导。     

Retrospective and perspective of rice breeding in China

Breeding is the art and science of selecting and changing crop traits for the benefit of human beings. For several decades, tremendous efforts have been made by Chinese scientists in rice breeding in improving grain yield, nutrition quality, and environmental performance, achieving substantial progress for global food security. Several generations of crop breeding technologies have been developed, for example, selection of better performance in the field among variants (conventional breeding), application of molecular markers for precise selection (molecular marker assisted breeding), and development of molecular design (molecular breeding by rational design). In this review, we briefly summarize the advances in conventional breeding, functional genomics for genes and networks in rice that regulate important agronomic traits, and molecular breeding in China with focuses on high yield, good quality, stress tolerance, and high nutrient-use efficiency. These findings have paved a new avenue for rational design of crops to develop ideal varieties with super performance and productivity.     

Structure for energy cycle: a unique status of the second law of thermodynamics for living systems

Distinguishing things from beings, or matters from lives, is a fundamental question. Extending E. Schr?dinger's neg-entropy and I. Prigogine's dissipative structure, we propose a chemical kinetic view that the earliest "live" process is embedded essentially in a special interaction between a pair of specific components under a particular, corresponding environmental conditions. The interaction exists as an inter-molecular-force-bond complex(IMFBC) that couples two separate chemical processes: one is the spontaneous formation of the IMFBC driven by a decrease of Gibbs free energy as a dissipative process; while the other is the disassembly of the IMFBC driven thermodynamically by free energy input from the environment. The two chemical processes coupled by the IMFBC originated independently and were considered non-living on Earth, but the IMFBC coupling of the two can be considered as the earliest form of metabolism: the first landmark on the path from things to a being. The dynamic formation and disassembly of the IMFBC, as a composite individual, follows a principle designated as "… structure for energy for structure for energy…", the cycle continues; and for short it will be referred to as "structure for energy cycle". With additional features derived from this starting point, the IMFBC-centered "live" process spontaneously evolved into more complex living organisms with the characteristics currently known.