Effects of harvesting time on fruit quality and internal browning of ��Wonhuwang�� pear during cold storage

Average fruit weight, seed browning, flesh firmness, total soluble solids, internal browning, and skin blackening were used to determine the optimum harvesting time of ‘Wonhuwang’ pear. Pears for storage were picked three times at 5-day intervals before, during, and after estimated optimum harvesting date. Average fruit weight and seed browning degree were calculated at each picking time. Quality changes, internal browning, and skin blackening were employed to estimate the optimum harvest date. It was found that fruit quality parameters both at harvest and after storage depended on the stage of ripeness at which the pears were picked. Pears harvested earliest (H1) had the highest firmness both before and after storage and lost less percentage of their firmness during storage. The latest picked pears (H3) showed higher total soluble solids value and serious internal browning and skin blackening due to their over ripeness. Pears picked on the 15th of August (H2) had higher firmness and total soluble solids, lower extent of internal browning, and no skin blackening. Based on the changes in fruit firmness and physiologic disorder during ripening and storage, the optimal harvesting time for ‘Wonhuwang’ pear in Shijiazhuang area is around the 15th of August.     

Genomic characteristics of Dickeya fangzhongdai isolates from pear and the function of type Ⅳ pili in the chromosome

Dickeya fangzhongdai, the causal agent of bleeding canker of pear, is a new member of the Dickeya genus and the only one that infects woody plants. Recent studies have reclassified several Dickeya isolates as D. fangzhongdai, which were isolated from various environments, including water, Phalaenopsis sp. and Aglaonema sp. To provide genomic characterization of D. fangzhongdai isolates from pear, the genomes of D. fangzhongdai strain JS5(=China General Microbiological Culture Collection Center, CGMCC 1.15464 ~T=DSM 101947 ~T), along with two other isolates, LN1 and QZH3, were sequenced and compared to those of other Dickeya spp. Homology greater than 99% was observed among three D. fangzhongdai strains. Plasmid, type IV secretion system(T4 SS) and type IV pili(TFPs) were found in genomes of D. fangzhongdai isolates. Comparative analysis of the type Ⅲ secretion systems(T3 SS), type Ⅲ secretion effectors(T3 SE), plant cell wall degradation enzymes(PCWDE) and membrane transport proteins of Dickeya spp. showed some differences which might reflect the variations of virulence, phylogenetic and phenotypic characteristics of Dickeya spp. In addition, deletion mutant of TFP in D. fangzhongdai JS5 showed no twitching motility and reduced virulence and biofilm formation. The fingdings of the distinctive plasmid, T4 SS and TFPs, as well as the differences of T3 SE, PCWDE and membrane transport proteins make D. fangzhongdai isolates unique. These results also suggested that acquisition of virulence genes by horizontal gene transfer might play some role in the genetic variation of D. fangzhongdai.     

An assessment of the genetic diversity of pear(Pyrus L.) germplasm resources based on the fruit phenotypic traits全文替换

Germplasm resources are an important basis for genetic breeding and analysis of complex traits, and research on genetic diversity is conducive to the exploration and creation of new types of germplasm. In this study, the distribution frequency, coefficient of variation, Shannon–Wiener index, and variance and cluster analyses were used to analyze the diversity and trait differences of 39 fruit phenotypic traits from 570 pear accessions, which included 456 pear accessions from 11 species and 114 i...     

Imperfect Competition and Common Resource Exploitation—An Analysis of Renewable Resource Management with Non—use Values

This article analyzes the importance of non-use values in the management of natural resources with a model of imperfect competition.By constucting a framework of duopolistic exploiters.the incorporation of non-use values based on self-interest and altruistic motives appears to be significant for determining the degree of inefficiency caused by the problem of common property at the non-cooperative Nash equilibrium.It is found that when the non-use value placed by the altruist exploiter is bounded by that placed by the pure selfinterest exploiter,the effect of market power is dominated by the effect of common exploitation.In this case,the exploiters‘ harvesting strategy will response in the same direction to the change of each other‘s harvesting at the non-cooperative Nash equilibrium.In contrast,when the non-use value placed by the altruist is substantially larger or smaller than that placed by the self-interest exploiter,one exploiter‘s increase in harvesting will lead to a decrease in harvesting of the other exploiter at the non-cooperative Nash equilibrium.     

Discuss on constructing the regional characteristics database of library of university——take ＂Regional characteristics of agricultural disease database＂ of the Guangxi University Library as an Example

特色馆藏建设是提高和丰富高校图书馆馆藏质量的重要手段,以＂区域特色农业病害数据库＂为例,分析了广西大学图书馆建设特色数据库选题的要求及意义,提出建设该特色数据库的具体方案及增加移动服务功能,全力打造特色鲜明、实用性强、价值突出的特色数据库。     

In vitro micro propagation of “sand pear” Pyrus pyrifolia (Burm. f.) Nakai

This study was undertaken to standardize protocols for in vitro explant establishment, shoot multiplication and in vitro rooting for Pyrus pyrifolia, growing in the Kashmir valley. The explant used was nodal cuttings of 2–3cm size with one or two axillary buds. The highest explant establishment (over 90%) was observed during spring while the lowest (60%) explant establishment frequency was observed during winter season. The shoots sprouted from the axillary buds were excised and subcultured on MS basal medium. The highest shoot multiplication rate (130 shoots from a single nodal cutting) was obtained on MS medium supplemented with BAP 2.2 mg·L^?1 and kinetin 1 mg·L^?1 after four weeks. The shoots were inoculated for rooting in root induction medium of half strength MS salts supplemented with plant growth regulators like IBA, IAA, NAA, and 2, 4-D. However, the best rooting response (8.50 roots per shoot) was obtained in combination of hormones (IBA + NAA) 0.25 mg·L^?1 each. The rooted micro shoots were acclimatized under decreasing humidity regime (95% RH to 75% RH over a period of 5±1 weeks). The highest ex vitro plantlet survival percentage (56.50%) of Pyrus pyrifolia was observed on sand + soil (1:1 v/v).     

An Analysis of Figurative Language in “Profits of Praise”

Figures of speech are often used to express the writer‘s ideas of thoughts more vividly and attractively.This paper chooses “Profits of Praise” as an example to analyze the effect of figures of speech on expressing the writer‘s ideas and comes to the conclusion that figures of speech play an important part in the expression of ideas,and they can help students understand the text better and help improve their writing.     

Adventitious shoot regeneration from the leaves of in vitro grown ‘Zhongli 1’ pear (Pyrus spp.)

The pear (Pyrus spp.) is one of the most important temperate fruit crops. The technique of adventitious shoot regeneration from leaves is considered to be one of the shortcuts in the research on pear genetic modification and cellular engineering, which, however, has not been widely used. As the regeneration frequency of pear leaves is usually very low, the research on adventitious shoot regeneration from pear leaves is eagerly needed. In this experiment, the factors affecting shoot and bud regeneration from the leaves of ‘Zhongli 1’ pear were studied, and an efficient protocol for shoot regeneration was established. The results showed that different types of basic media, different combinations of plant growth regulators, leaf placement on medium, periods of dark culture and the use of silver nitrate (AgNO₃) on culture media all significantly affected the adventitious shoot regeneration frequency of ‘Zhongli 1’ pear. The details are as follows: (1) Among three kinds of basic media, NN69 was better for ‘Zhongli 1’ shoot regeneration, followed by half (½) MS, while full MS had no effect on shoot regeneration; (2) Thidiazuron (TDZ) was better than 6-benzylaminopurine (6-BA) for ‘Zhongli 1’ regeneration, with an optimal concentration of 1.5 mg · L^?1, and the regeneration rate under this concentration could reach 85%, with 2.72 buds per leaf. 0.5 mg · L^?1 indole-3-butyric acid (IBA), which induced a higher regeneration frequency, was a better choice for pear regeneration compared with 0.3 mg · L^?1 naphthaleneacetic acid (NAA). Among the different combinations of plant growth regulators, TDZ + IBA was better for inducing high regeneration frequency; (3) The abaxial surface of leaves touching the medium was beneficial for leaves to uptake nutrients from the medium, and because of that, the regeneration frequency of leaves was significantly higher than that of leaves touching the medium with their adaxial surfaces (obverse side of leaf); (4) Dark culture was necessary for bud regeneration, and the best duration for dark culture of ‘Zhongli 1’ pear was 21 days; (5) The addition of 1.0 mg · L^?1 AgNO₃ into the culture medium could promote adventitious shoot regeneration significantly. A high adventitious shoot regeneration frequency was obtained in this research, which will be beneficial for further research on efficient and stable in vitro plant regeneration systems and genetic modification of pear.     

An expanded palette of genetically encoded Ca²⁺ indicators

Engineered fluorescent protein (FP) chimeras that modulate their fluorescence in response to changes in calcium ion (Ca(2+)) concentration are powerful tools for visualizing intracellular signaling activity. However, despite a decade of availability, the palette of single FP-based Ca(2+) indicators has remained limited to a single green hue. We have expanded this palette by developing blue, improved green, and red intensiometric indicators, as well as an emission ratiometric indicator with an 11,000% ratio change. This series enables improved single-color Ca(2+) imaging in neurons and transgenic Caenorhabditis elegans. In HeLa cells, Ca(2+) was imaged in three subcellular compartments, and, in conjunction with a cyan FP-yellow FP-based indicator, Ca(2+) and adenosine 5'-triphosphate were simultaneously imaged. This palette of indicators paints the way to a colorful new era of Ca(2+) imaging.     

Factors affecting the adoption of on-farm milk safety measures in Northern China — An examination from the perspective of farm size and production type

The cow stock of smallholder farmers with less than 100 cows still accounted for nearly 50% of total cows in China. Since the milk scandal occurred in 2008, raw milk safety has become focus for the sound development of the Chinese dairy industry. Adoption of on-farm milk safety measures by smallholders is a key for ensuring milk safety, and these measures are largely voluntary in nature. The recent survey conducted in northern China reveals that an overall adoption rate of various milk safety measures by smallholders is close to 48% with wide variations across the dairy farmers. We employ the Poisson regression model to study the determinants of farmers' adoption of voluntary milk safety measures. Compared with backyard dairy farmers, dairy complex and scaled dairy farms adopted more milk safety measures. Moreover, the empirical result indicates that farmers' adoption of raw milk safety measures is positively affected by farm size. These findings suggest that the changing dairy production structure towards larger farms and away from backyard dairy farming prompts smallholder dairy farmers to adopt more raw milk safety measures. This lends some support to the role of recent policy initiatives towards larger farms and away from backyard dairy farming on increasing the farmers' milk safety practices and reducing on-farm incidence of milk safety.     

Does rejection hurt? An FMRI study of social exclusion

A neuroimaging study examined the neural correlates of social exclusion and tested the hypothesis that the brain bases of social pain are similar to those of physical pain. Participants were scanned while playing a virtual ball-tossing game in which they were ultimately excluded. Paralleling results from physical pain studies, the anterior cingulate cortex (ACC) was more active during exclusion than during inclusion and correlated positively with self-reported distress. Right ventral prefrontal cortex (RVPFC) was active during exclusion and correlated negatively with self-reported distress. ACC changes mediated the RVPFC-distress correlation, suggesting that RVPFC regulates the distress of social exclusion by disrupting ACC activity.     

Stable Isotope Technique—An Advanced Technology in Ascertaining Plant-Water Relations

介绍了稳定同位素的一些关键术语和相关标准,探讨了研究植物水分关系中 C、H、O三种稳定同位素的确定及其同位素效应,同时主要从植物水分来源、水分利用效率、根系吸收水分最活跃区域、植物群落内不同物种水资源利用差异等几个方面阐述了稳定同位素先进技术的应用进展,最后指出稳定同位素技术在植物水分关系研究中存在的问题。旨在此文能起到抛砖引玉的作用,以此推动稳定同位素技术在我国植物水分利用研究甚至整个生态学领域研究中的可持续发展。     

Immunological changes of chicken infected with marek‘s disease virus

The experiment was conducted to infect one-day old healthy AA chicks with virulent Marek‘s disease virus(MDV).Compared with the uninfected control chicks,it was undertaken to detect the inductive activity of interlukin-2,expression of IL-2 recepter(IL-2R)and proliferative reaction of T cell in the thymus and spleen;to determine the number of α-naphthyl esterase positive T cells,acid phosphatase positive T cells and antibody forming cells in the thymus,Bursa Fabricius,spleen,cecal tonsil,Harder gand and mucosal lympoid tissue of bronchus;to check the number of T cell in peripheral blood as well as the dynamic changes of the amount of IgG,IgM and IgA in the serum,tear,trachea washings and intestinal secretions of infected chickens at 5,25,45 days old,respectively.The experimental results reveal that immunoregulation of IL-2 in immune organs of infected chicknens was disordered;the cellular and humoral immune functions were significantly depressed in the central and peripheral immune organs;the local or mucosal immune defense function were also markedly decreased in respiratory and digestive tracts.     

The genetics of adult-onset neuropsychiatric disease: complexities and conundra?

Genetic factors play a major role in the etiology of adult-onset neurodegenerative and neuropsychiatric disorders. Several highly penetrant genes have been cloned for rare, autosomal-dominant, early-onset forms of neurodegenerative diseases. These genes have provided important insights into the mechanisms of these diseases (often altering neuronal protein processing). However, the genes associated with inherited susceptibility to late-onset neurodegenerative diseases, schizophrenia, and bipolar disorder appear to have smaller effects and are likely to interact with each other (and with nongenetic factors) to modulate susceptibility and/or disease phenotype. Several strategies have recently been applied to address this complexity, leading to the identification of a number of candidate susceptibility loci/genes.     

The investigation stride of mucosal immunoloagy and animal infectious disease preservation

黏膜免疫学研究是近几年来研究进展最快的领域之一。黏膜免疫的规律、特点及其调控机制等方面的知识得到了丰富和充实,并且对黏膜相关的疫病的发生机制及其防制提供了新的依据。在此,就黏膜免疫学的意义、黏膜免疫的主要途径、黏膜免疫与动物疫病防制、黏膜免疫与疫苗、黏膜免疫的研究动态等进行了综述。