Association between sheath blight resistance and chitinase activity in transgenic rice plants expressing McCHIT1 from bitter melon

No usable resources with high-level resistance to sheath blight (SB) have yet been found in rice germplasm resources worldwide. Therefore, creating and breeding new disease-resistant rice resources with sheath blight resistance (SBR) are imperative. In this study, we inoculated rice plants with hyphae of the highly pathogenic strain RH-9 of rice SB fungus Rhizoctonia solani to obtain eight stable transgenic rice lines harbouring the chitinase gene (McCHIT1) of bitter melon with good SBR in the T₅ generation. The mean disease index for SB of wild-type plants was 92% and 37–44% in transgenic lines. From 24 h before until 120 h after inoculation with R. solani, chitinase activity in stable transgenic plants with increased SBR was 2.0–5.5 and 1.8–2.7 times that of wild-type plants and plants of a disease-susceptible stable transgenic line, respectively. The correlation between SBR and chitinase activity in McCHIT1-transgenic rice line plants was significant. This work stresses how McCHIT1 from bitter melon can be used to protect rice plants from SB infection.

     

Realizing Three‐Electron Redox Reactions in NASICON‐Structured Na3MnTi(PO4)3 for Sodium‐Ion Batteries

Developing multielectron reaction electrode materials is essential for achieving high specific capacity and high energy density in secondary batteries; however, it remains a great challenge. Herein, Na₃MnTi(PO₄)₃/C hollow microspheres with an open and stable NASICON framework are synthesized by a spray‐drying‐assisted process. When applied as a cathode material for sodium‐ion batteries, the resultant Na₃MnTi(PO₄)₃/C microspheres demonstrate fully reversible three‐electron redox reactions, corresponding to the Ti^3+/4+ (≈2.1 V), Mn^2+/3+ (≈3.5 V), and Mn^3+/4+ (≈4.0 V vs Na⁺/Na) redox couples. In situ X‐ray diffraction results reveals that both solid‐solution and two‐phase electrochemical reactions are involved in the sodiation/desodiation processes. The high specific capacity (160 mAh g^?1 at 0.2 C), outstanding cyclability (≈92% capacity retention after 500 cycles at 2 C), and the facile synthesis make the Na₃MnTi(PO₄)₃/C a prospective cathode material for sodium‐ion batteries.     

芦苇湿地温室气体甲烷(CH4)排放研究

用封闭式箱法对辽河三洲芦苇湿地温室气候CH4的观测结果表明,其排放有明显的季节规律。淹水前、土壤为CH4汇。淹水期间,有大量的CH4排放。排水后CH4排放明显减少。在测定期内,CH4排放通量为－968－2734μgCH4l/(m^2.h)。另外,土壤中中产生的CH4主要是通过芦苇植株的传输作用进入到大气中,试验结果还表明,有芦苇生长的湿地CH4排放是无芦苇生长的15倍,同时,建议芦苇田应采用间歇灌溉的水分管理措施,这样既促进植株生长,又能减少CH4排放。     

近33年白洋淀景观动态变化

湿地具有重要的生态功能,由于各种因素的影响改变了湿地水文条件,并且导致湿地退化。利用1974、1987、1996和2007年遥感影像,使用ERDAS 9.1、ARCGIS 9.2和FRAGSTATS 3.3,分析了白洋淀景观动态变化过程及其驱动力。研究结果表明:从1974至2007年,白洋淀湿地面积从249.4km²下降到182.6km²,农田和居民地面积分别从70.0、2.1km²增加到126.4、12.5km²;在景观水平上,斑块密度、景观形状指数和香农多样性指数增加,蔓延度减小,景观破碎化程度增加,优势景观类型湿地对整个景观的控制作用减小;在类型水平上,明水面和沼泽的斑块密度和周长-面积分维数增加,最大斑块指数、平均斑块面积和连接度减小,居民地的斑块密度、最大斑块指数、平均斑块面积、周长-面积分维数和连接度都增加,农田的斑块密度、最大斑块指数和连接度增加,平均斑块面积和周长-面积分维数减小;水位变化是影响白洋淀景观变化的主要因素,水位升高会使湿地面积增加,反之,使湿地面积减小;流域人类活动和降水量变化是白洋淀水位和景观变化的重要驱动力。引水补淀只能暂时缓解白洋淀缺水问题,从流域角度考虑,实施有效的水资源管理方式,才能从根本上解决白洋淀湿地退化的问题。     

A ribosomal frameshifting error during translation of the argl mRNA of Escherichla coli

Using fusions between the Escherichia coli genes argI and lacZ, it has been demonstrated that ribosomal frameshifting occurs at a frequency of between 3% and 16% within the argl mRNA, soon after the initiation codon. The frameshift involves a phenylalanyl-tRNA shifting into the + 1 frame at the sequence UUU-U/C. The shift does not occur if the in-frame phenylalanine codon UUU is replaced by UUC. The level of frameshifting is higher in dense cultures and is not dependent on phenylalanine starvation. In the wild-type argI gene this frameshifting event would be an error, leading to a truncated, non-functional protein. Therefore, it is unlike the numerous examples of required frameshifting events that have been described in other genes.     

Association of RAGE gene polymorphisms with type 2 diabetes mellitus,diabetic retinopathy and diabetic nephropathy

A meta-analysis was performed to assess the associations of the receptor for advanced glycation end products (RAGE) gene polymorphisms [Gly82Ser (rs2070600), 1704 G/T (rs184003), 429 T/C (rs1800625)] with type 2 diabetes mellitus (T2DM), diabetic retinopathy (DR) and diabetic nephropathy (DN). A comprehensive research was conducted to identify all case-control or cohort studies. The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I². Meta-regression was used to explore the potential sources of between-study heterogeneity. Publication bias was estimated using Peters test. Twenty-nine articles were included. Overall, after excluding articles deviating from Hardy–Weinberg equilibrium in controls and sensitive analysis, no significant association was found between RAGE gene polymorphisms (Gly82Ser, 1704 G/T, 429 T/C) and any of T2DM, DR and DN risk, respectively. Subgroup analysis stratified by ethnicity (Asian and Caucasian) also found no significant association between the above-mentioned three polymorphisms and T2DM risk, respectively. This meta-analysis suggested that there might be no association of RAGE gene polymorphisms (Gly82Ser, 1704 G/T, 429 T/C) with T2DM, DR and DN risk.     

Construction of High-Density Genetic Linkage Maps and Mapping of Growth-Related Quantitative Trail Loci in the Japanese Flounder (Paralichthys olivaceus)

High-density genetic linkage maps were constructed for the Japanese flounder (Paralichthys olivaceus). A total of 1624 microsatellite markers were polymorphic in the reference family. Linkage analysis using JoinMap 4.0 resulted in the mapping of 1487 markers to 24 linkage groups, a result which was consistent with the 24 chromosomes seen in chromosome spreads. The female map was composed of 1257 markers, covering a total of 1663.8 cM with an average interval 1.35 cM between markers. The male map consisted of 1224 markers, spanning 1726.5 cM, with an average interval of 1.44 cM. The genome length in the Japanese flounder was estimated to be 1730.3 cM for the females and 1798.0 cM for the males, a coverage of 96.2% for the female and 96.0% for the male map. The mean recombination at common intervals throughout the genome revealed a slight difference between sexes, i.e. 1.07 times higher in the male than female. High-density genetic linkage maps are very useful for marker-assisted selection (MAS) programs for economically valuable traits in this species and for further evolutionary studies in flatfish and vertebrate species. Furthermore, four quantiative trait loci (QTL) associated with growth traits were mapped on the genetic map. One QTL was identified for body weight on LG 14 f, which explained 14.85% of the total variation of the body weight. Three QTL were identified for body width on LG14f and LG14m, accounting for 16.75%, 13.62% and 13.65% of the total variation in body width, respectively. The additive effects were evident as negative values. There were four QTL for growth traits clustered on LG14, which should prove to be very useful for improving growth traits using molecular MAS.     

Impaired small-world network efficiency and dynamic functional distribution in patients with cirrhosis

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome and a major complication of liver cirrhosis. Dysmetabolism of the brain, related to elevated ammonia levels, interferes with intercortical connectivity and cognitive function. For evaluation of network efficiency, a 'small-world' network model can quantify the effectiveness of information transfer within brain networks. This study aimed to use small-world topology to investigate abnormalities of neuronal connectivity among widely distributed brain regions in patients with liver cirrhosis using resting-state functional magnetic resonance imaging (rs-fMRI). Seventeen cirrhotic patients without HE, 9 with minimal HE, 9 with overt HE, and 35 healthy controls were compared. The interregional correlation matrix was obtained by averaging the rs-fMRI time series over all voxels in each of the 90 regions using the automated anatomical labeling model. Cost and correlation threshold values were then applied to construct the functional brain network. The absolute and relative network efficiencies were calculated; quantifying distinct aspects of the local and global topological network organization. Correlations between network topology parameters, ammonia levels, and the severity of HE were determined using linear regression and ANOVA. The local and global topological efficiencies of the functional connectivity network were significantly disrupted in HE patients; showing abnormal small-world properties. Alterations in regional characteristics, including nodal efficiency and nodal strength, occurred predominantly in the association, primary, and limbic/paralimbic regions. The degree of network organization disruption depended on the severity of HE. Ammonia levels were also significantly associated with the alterations in local network properties. Results indicated that alterations in the rs-fMRI network topology of the brain were associated with HE grade; and that focal or diffuse lesions disturbed the functional network to further alter the global topology and efficiency of the whole brain network. These findings provide insights into the functional changes in the human brain in HE.