黄单胞杆菌XC—82,R5二步发酵工艺研究

通过对黄单胞杆菌ＸＣ－８２,Ｒ５株的黄原胶二步发酵工艺研究,针对菌株在生长时期与产胶时期不同培养条件的需求,确定了两个阶段各自适宜的培养基组成,温度,ｐＨ值条件,实验表明,当流加稀释率为５时,二步发酵生产可达到了较高水平,其产胶量较传统的间歇发酵提高３１％。     

No‐tillage and fertilization management on crop yields and nitrate leaching in North China Plain

A field experiment was performed from 2003 to 2008 to evaluate the effects of tillage system and nitrogen management regimes on crop yields and nitrate leaching from the fluvo-aquic soil with a winter wheat (Triticum aestivum L.)–maize (Zea mays L.) double-cropping system. The tillage systems consisted of conventional tillage (CT) and no-tillage (NT). Three nitrogen management regimes were included: 270 kg N ha⁻¹ of urea for wheat and 225 kg N ha⁻¹ of urea for maize (U), 180 kg N ha⁻¹ of urea and 90 kg N ha⁻¹ of straw for wheat and 180 kg N of urea and 45 kg N ha⁻¹ of straw for maize (S), 180 kg N ha⁻¹ of urea and 90 kg N ha⁻¹ of manure for wheat and 180 kg N ha⁻¹ of urea and 45 kg N ha⁻¹ of manure for maize (M). An array of tension-free pan lysimeters (50 cm × 75 cm) were installed (1.2 m deep) to measure water flow and -N movement. No significant effect of the N management regime on yields of winter wheat and maize grain was found in the 5-year rotation. Tillage systems had significant influences on -N leaching from the second year and thereafter interacted with N management regimes on -N loads during all maize seasons. The average yield-scaled -N leaching losses were in order of CTS < NTS< CTU < NTU −1 for winter wheat system and from 0.99 (CTS) to 6.27 (NTM) kg N Mg⁻¹ for summer maize system for 5 rotation years. The results showed that CTS decreased the yield-scaled -N leaching losses while sustaining crop grain yields. Considering the lower costs, NTS could be a potential alternative to decrease yield-scaled -N leaching losses and improve soil fertility while maintaining crop yield for the winter wheat–maize double-cropping systems in the North China Plain.     

Inducing drought tolerance in plants: Recent advances

Undoubtedly, drought is one of the prime abiotic stresses in the world. Crop yield losses due to drought stress are considerable. Although a variety of approaches have been used to alleviate the problem of drought, plant breeding, either conventional breeding or genetic engineering, seems to be an efficient and economic means of tailoring crops to enable them to grow successfully in drought-prone environments. During the last century, although plant breeders have made ample progress through conventional breeding in developing drought tolerant lines/cultivars of some selected crops, the approach is, in fact, highly time-consuming and labor- and cost-intensive. Alternatively, marker-assisted breeding (MAB) is a more efficient approach, which identifies the usefulness of thousands of genomic regions of a crop under stress conditions, which was, in reality, previously not possible. Quantitative trait loci (QTL) for drought tolerance have been identified for a variety of traits in different crops. With the development of comprehensive molecular linkage maps, marker-assisted selection procedures have led to pyramiding desirable traits to achieve improvements in crop drought tolerance. However, the accuracy and preciseness in QTL identification are problematic. Furthermore, significant genetic × environment interaction, large number of genes encoding yield, and use of wrong mapping populations, have all harmed programs involved in mapping of QTL for high growth and yield under water limited conditions. Under such circumstances, a transgenic approach to the problem seems more convincing and practicable, and it is being pursued vigorously to improve qualitative and quantitative traits including tolerance to biotic and abiotic stresses in different crops. Rapid advance in knowledge on genomics and proteomics will certainly be beneficial to fine-tune the molecular breeding and transformation approaches so as to achieve a significant progress in crop improvement in future. Knowledge of gene regulation and signal transduction to generate drought tolerant crop cultivars/lines has been discussed in the present review. In addition, the advantages and disadvantages as well as future prospects of each breeding approach have also been discussed.     

REDHORSE-REcombination and Double crossover detection in Haploid Organisms using next-geneRation SEquencing data

Background

Next-generation sequencing technology provides a means to study genetic exchange at a higher resolution than was possible using earlier technologies. However, this improvement presents challenges as the alignments of next generation sequence data to a reference genome cannot be directly used as input to existing detection algorithms, which instead typically use multiple sequence alignments as input. We therefore designed a software suite called REDHORSE that uses genomic alignments, extracts genetic markers, and generates multiple sequence alignments that can be used as input to existing recombination detection algorithms. In addition, REDHORSE implements a custom recombination detection algorithm that makes use of sequence information and genomic positions to accurately detect crossovers. REDHORSE is a portable and platform independent suite that provides efficient analysis of genetic crosses based on Next-generation sequencing data.

Results

We demonstrated the utility of REDHORSE using simulated data and real Next-generation sequencing data. The simulated dataset mimicked recombination between two known haploid parental strains and allowed comparison of detected break points against known true break points to assess performance of recombination detection algorithms. A newly generated NGS dataset from a genetic cross of Toxoplasma gondii allowed us to demonstrate our pipeline. REDHORSE successfully extracted the relevant genetic markers and was able to transform the read alignments from NGS to the genome to generate multiple sequence alignments. Recombination detection algorithm in REDHORSE was able to detect conventional crossovers and double crossovers typically associated with gene conversions whilst filtering out artifacts that might have been introduced during sequencing or alignment. REDHORSE outperformed other commonly used recombination detection algorithms in finding conventional crossovers. In addition, REDHORSE was the only algorithm that was able to detect double crossovers.

Conclusion

REDHORSE is an efficient analytical pipeline that serves as a bridge between genomic alignments and existing recombination detection algorithms. Moreover, REDHORSE is equipped with a recombination detection algorithm specifically designed for Next-generation sequencing data. REDHORSE is portable, platform independent Java based utility that provides efficient analysis of genetic crosses based on Next-generation sequencing data. REDHORSE is available at http://redhorse.sourceforge.net/.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1309-7) contains supplementary material, which is available to authorized users.     

Estimation of Heritability in Heteroscedastic One‐Way Unbalanced Random Model

A modified estimator of heritability is proposed under heteroscedastic one way unbalanced random model. The distribution, moments and probability of permissible values (PPV) for conventional and modified estimators are derived. The behaviour of two estimators has been investigated, numerically, to devise a suitable estimator of heritability under variance heterogeneity. The numerical results reveal that under balanced case the heteroscedasticity affects the bias, MSE and PPV of conventional estimator, marginally. In case of unbalanced situations, the conventional estimator underestimates the parameter when more variable group has more observations and overestimates when more variable group has less observations, MSE of the conventional estimator decreases when more variable group has more observations and increases when more variable group has less observations and PPV is marginally decreased. The MSE and PPV are comparable for two estimators while the bias of modified estimator is less than the conventional estimator particularly for small and medium values of the parameter. These results suggest the use of modified estimator with equal or more observations for more variable group in presence of variance heterogeneity.     

经胸前壁入路内镜甲状腺手术与传统甲状腺手术的 对照研究

目的:通过临床非随机性对照研究,比较经胸前壁入路内镜甲状腺手术与传统甲状腺手术在手术时间、术中出血量、术后引流量、术后疼痛、功能恢复、术后住院时间、住院费用及美容效果上的不同,探讨经胸前壁入路内镜甲状腺手术的可行性及临床效果。方法:回顾性分析86例甲状腺手术,其中46例患者采用经胸前壁入路内镜甲状腺手术的患者为内镜组,40例行传统甲状腺手术为传统组。结果:两组患者均顺利完成手术,术后恢复良好,均未发生术后大出血、喉返神经、喉上神经及甲状旁腺损伤等并发症。两组患者的术后住院时间及术后引流量无显著差异。与传统组比较,内镜组手术时间明显延长(P<0.05),术中出血量明显减少(P<0.05),术后疼痛明显降低(P<0.05),功能恢复即术后自行下床洗漱时间明显缩短(P<0.05),住院费用显著增加(P<0.05),手术美容效果满意度明显提高(P<0.05)。结论:相对传统甲状腺手术,经胸前壁入路内镜甲状腺手术具有切口小、出血量少、术后疼痛轻、功能恢复快、美容满意度高等优点,是治疗甲状腺疾病安全、有效的手术方法。     

Olive oil history,production and by-product management

In this review paper, the history of the olive tree and the development of the main olive oil extraction systems employed in the past are presented. Furthermore, the management techniques employed from antiquity until today for the treatment of olive mill wastewater (OMW), which constitutes the most important by-product of olive oil production, are addressed and compared. Reference is also made to global olive oil production, the environmental impacts of the uncontrolled disposal of OMW, and to the legal framework concerning its management in the main olive oil producing countries. Other by-products of olive processing are also discussed.     

进化稳定对策

进化稳定对策（ESS）是对策论的核心概念,在进化生物学研究中有着非常重要的意义,该理论被认为是自Darwin以来进化论最重要的发展之一。阐释进化稳定对策基本理论的产生以及几种重要的进化稳定对策模型,并运用进化稳定对策理论解释一些生物现象。     

微生态制剂治疗肝源性肠道菌群失调与保肝作用

目的:观察采用常规保肝治疗及或加服乐托尔或加服培菲康来治疗慢性肝病疗效.方法:慢迁肝41例及慢活肝37例,各随机分成三组:A组:常规治疗 乐托尔胶囊,2粒/次,2次/d;B组:常规治疗 培菲康胶囊,3粒/次,3次/d;C组:常规治疗:益肝灵 Vit.C Vit.B Co,各2片/次,3次/d,三组疗程均为2个月.结果:75例完成治疗及复查,失访3例.腹胀、腹泻、肝区不适消失率及ALT、内毒素试验复常率二项三组相比有显著意义(P<0.01).乏力、SB复常率在慢活肝中三组相比有显著意义(P<0.01).总有效率:慢迁肝三组分别为83.3%、69.2%、35.7%;慢活肝三组分别为:63.7%、61.5%、33.3%,三组相比有显著意义(P<0.01).结论:常规保肝治疗加服微生态制剂,不论是死菌及其代谢产物或活菌制剂均有肯定的价值,但死菌制剂具有活菌制剂不具备的优点.     

The dynamics of experimental arable weed communities under different management practices

Abstract. Weed communities, comprising 12 introduced species at constant starting densities and three species already present in the seed bank, were followed through three years of continuous winter wheat. The wheat and weeds were subjected to two treatments in a split-plot factorial design, organic contrasting with conventional fertilizer, and ploughing plus hand-roguing contrasting with minimum tillage plus herbicide. The minimum tilled plots developed in a uniform manner, and became dominated by very high densities of Anisantha sterilis. Agrostemma githago and Galium aparine also persisted in these plots at lower densities. The ploughed plots had a lower total density but a greater range of species. Stellaria media, Veronica persica and Avena fatua were the most common; other species occurred at lower densities. The major effect of fertilizer treatment was a greater initial increase by G. aparine on the organic, minimum tilled plots compared with the conventionally fertilized, minimum tilled plots. Species associated with minimum tillage were annuals with either no or a short term seed bank and autumn germination and rather predictable dynamics, whereas species that did well under ploughing were either spring germinating or had a persistent seed bank, implying greater annual variation in population size associated with weather conditions. There seemed no clear way to distinguish between those species which were abundant on the ploughed plots and those which were scarce under all conditions using readily accessible data.