Molecular architecture and assembly principles of Vibrio cholerae biofilms

In their natural environment, microbes organize into communities held together by an extracellular matrix composed of polysaccharides and proteins. We developed an in vivo labeling strategy to allow the extracellular matrix of developing biofilms to be visualized with conventional and superresolution light microscopy. Vibrio cholerae biofilms displayed three distinct levels of spatial organization: cells, clusters of cells, and collections of clusters. Multiresolution imaging of living V. cholerae biofilms revealed the complementary architectural roles of the four essential matrix constituents: RbmA provided cell-cell adhesion; Bap1 allowed the developing biofilm to adhere to surfaces; and heterogeneous mixtures of Vibrio polysaccharide, RbmC, and Bap1 formed dynamic, flexible, and ordered envelopes that encased the cell clusters.     

Cloning and Characterization of Boar Epididymal Secretory Proteins by Homology to the Human

Northern blot analysis suggested that the boar epididymis produces closely related counterparts to human epididymal proteins HE1, HE3, HE4, HE5 and HE12. ‘Full‐length’ cloning by nucleic acid and amino acid sequence similarity was achieved by RT‐PCR methods in the case of the porcine counterparts of HE3 and HE4, while the homologues of HE5 and HE12, despite their cross‐hybridization during Northern blot analysis, have not yet been cloned. The two novel porcine cDNAs were derived from moderately abundant epididymal mRNAs that were 75 and 83% identical to HE3 and HE4 cDNAs, respectively. To emphasize their relationship to the corresponding HEs, they were named Se3 and Se4 cDNAs. Their open reading frames predicted small secretory proteins with 55% (Se3) and 76% (Se4) conserved amino acids. Monospecific antipeptide antibodies to HE secretory proteins identified He3‐ and HE12‐related proteins on Western blots of porcine epididymal fluid and semen. Both Northern and Western analyses indicated that the Se proteins were produced in a regionalized pattern and accumulated in the cauda fluid.     

应用免疫金探针定位和定量测定稻种中的水稻细菌性条斑病菌

本文首次报道用免疫金染色和免疫金银染色对水稻细菌性条斑病病种的带菌部位及带菌量的研究。结果表明:病原细菌分布于谷壳、籽实皮、胚和胚乳,主要集中在谷壳上。谷壳外表带菌量多于内表面。籽实皮外表面由于受谷壳污染较之内表面的带菌量多。籽实皮内表面、胚和胚乳的带菌量均较少,差异不显著。谷壳、谷壳内表面、籽实皮、胚乳(或胚)的带菌量之比为36:13:9:1。     

Effect of growth differentiation factor‐9 (GDF‐9) on the progression of buffalo follicles in vitrified–warmed ovarian tissues

To improve the reproductive performance of water buffalo to level can satisfy our needs, the mechanisms controlling ovarian follicular growth and development should be thoroughly investigated. Therefore, in this study, the expressions of growth differentiation factor‐9 (GDF‐9) in buffalo ovaries were examined by immunohistochemistry, and the effects of GDF‐9 treatment on follicle progression were investigated using a buffalo ovary organ culture system. Frozen–thawed buffalo ovarian follicles within slices of ovarian cortical tissue were cultured for 14 days in the presence or absence of GDF‐9. After culture, ovarian slices were fixed, sectioned and stained. The follicles were morphologically analysed and counted. Expression pattern of GDF‐9 was detected in oocytes from primordial follicles onwards, besides, also presented in granulosa cells. Moreover, GDF‐9 was detected in mural granulosa cells and theca cells of pre‐antral follicles. In antral follicles, cumulus cells and theca cells displayed positive expression of GDF‐9. In corpora lutea, GDF‐9 was expressed in both granulosa and theca lutein cells. After in vitro culture, there was no difference in the number of primordial follicles between cultured plus GDF‐9 and cultured control that indicated the GDF‐9 treatment has no effect on the primordial to primary follicle transition. GDF‐9 treatment caused a significant decrease in the number of primary and secondary follicles compared with controls accompanied with a significant increase in pre‐antral and antral follicles. These results suggest that a larger number of primary and secondary follicles were stimulated to progress to later developmental stages when treated with GDF‐9. Vitrification/warming of buffalo ovarian tissue had a little remarkable effect, in contrast to culturing for 14 days, on the expression of GDF‐9. In conclusion, treatment with GDF‐9 was found to promote progression of primary follicle that could provide an alternative approach to stimulate early follicle development and to improve therapies for the most common infertility problem in buffaloes (ovarian inactivity).     

Tree stability in an improved soil to withstand wind loading

As trees are planted in close proximity to properties and humans in a dense city like Singapore, uprooting of trees can pose safety concerns. Previous research studies have shown that soil properties are important factors that govern tree stability. Soil properties can be improved by mixing top soil (TS) with coarse-grained soil. The effects of soil improvement using coarse-grained soil on tree stability were investigated in this study. Granite chip was used as coarse-grained soil to improve the original top soil. Static analysis and finite element modeling were performed to study tree stability in an improved soil. Factors investigated include root geometry and soil shear strength parameter. Finite element results showed good agreement with static analysis in determining the maximum wind force needed to uproot the tree. Parametric study showed that the wind force needed to uproot the tree was influenced by the mode of failure and the magnitude was dependant on the root geometry and the soil properties. A mixture of 20% top soil and 80% granite chip by dry mass was the optimum mixture for withstanding the maximum wind force needed to uproot the tree.     

Maximum vs minimum harmonization: what to expect from the institutional and legal battles in the EU on gene editing technologies

New plant‐breeding technologies (NPBTs), including gene editing, are widely used and drive the development of new crops. However, these new technologies are disputed, creating uncertainty in how their application for agricultural and food uses will be regulated. While in North America regulatory systems respond with a differentiated approach to NPBTs, the Court of Justice of the European Union (EU) has in effect made most if not all NPBT subject to the same regulatory regime as genetically modified organisms (GMOs). This paper discusses from a law and economics point of view different options that are available for the EU's multi‐level legal order. Using an ex‐ante regulation versus ex‐post liability framework allows the economic implications of different options to be addressed. The results show that under current conditions, some options are more expensive than others. The least costly option encompasses regulating new crops derived from NPBTs similar to those used in ‘conventional’ breeding. The current regulatory situation in the EU, namely making the use of NPBTs subject to the same conditions as GMOs, is the most costly option. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Alkylation of spiropyran moiety provides reversible photo-control over nanostructured soft materials

The purpose of this study was to create a light responsive nanostructured liquid crystalline matrix using a novel alkylated spiropyran photochromic molecule (spiropyran laurate, SPL) as a light activated drug delivery system. The liquid crystal matrix, prepared from phytantriol, responds reversibly to changes in photoisomerism of SPL on irradiation, switching between the bicontinuous cubic and the reversed hexagonal liquid crystal structures, a change previously shown to dramatically alter drug release rate. In contrast, the non-derivatized spiropyran and spirooxazine photochromic compounds do not sufficiently disrupt the matrix on isomerization to induce the phase change. Thus, novel alkylated spiropyran has the potential to be an effective agent for use in liquid crystalline systems for reversible 'on-demand' drug delivery applications.     

A study of reusing vinyl sulfone based reactive dye for dyeing cotton fiber

Reactive dye is a popular dye for dyeing cotton fiber due to its very good color fastness which is explained by the formation of covalent bond between dye and fiber. In this study, practicality of reuse of reactive dye by compensating for the hydrolyzed part of the dye solution is examined. A monofunctional dye (vinyl sulfone type) was used and it was found that dyeing cotton fiber with reused dyebath is possible. Since bifunctional dye can improve the chance of dye-fiber bond formation, vinyl sulfone based bifunctional reactive dyes were also selected in this study. Three types of bifunctional dyes were used and they basically share the same vinyl sulfone group; other reactive groups are monochlorotriazine, dichlorotriazine and vinyl sulfone. Such dyes were chosen in order to compare their respective efficiencies under the effect of one common reactive group. The aim of this study was to compare the effect of hydrolyzed and unhydrolyzed proportions of mono-and bifunctional reactive dyes on cotton fiber and study the possibility and efficiency of the two different reuse dyebath systems.     

Effect of supplemental nitrogen on true potato seed weight

The effect on true potato seed (TPS) weight of supplemental nitrogen (N) applied during seed development was investigated using crosses DTO-33 × R128.6 (“A” produced in the field) and Atzimba × R128.6 (“B” produced in the field and in a screenhouse). Dry weights of tops and tubers of the mother plants were also measured in the screenhouse. The response to supplemental N (0-240 kg/ha) in 100-TPS weight of cross A and B from the field was positive and linear. In the screenhouse, where higher total N (0-1200 kg/ha) was applied, the responses in 100-TPS weight and dry weight of tops and tubers were curvilinear, with maximum levels at 800, 1000 and 400 kg/ha, respectively. The 100-TPS weight of cross B was 40% higher in the field than in the screenhouse. In the field, increased frequency of supplemental N applications increased 100-TPS weight of large and medium berries of cross B, but had no effect on seed from small berries nor on seed from any berries of cross A. In the screenhouse, increased application frequency decreased tuber dry weight and increased dry weight of tops, but had no effect on 100-TPS weight. It was concluded that supplemental N must be applied during seed development and at higher total levels than those required for optimum tuber yields in order to maximize 100-TPS weight. The lower seed weight from the screenhouse suggests that other environmental factors (e.g., temperature) present during growth of the mother plant can affect the weight of the resultant TPS.     

云南高原甘薯地方品种征集鉴定研究

 自1993年以来,分别深入到云南省的14个地、州、市,45个县、区实地征集甘薯地方品种资源。1995～1996年将收集到的105份地方品种材料进行田间比较鉴定。对地区来源相同,名称相似的品种材料进行分类比较,初步认定。根据植物学形态特征和生理生态特性,对一些同名异种,异名同种的品种材料进行了认真的区分、整理、归并。将全省所征集到的105份甘薯地方品种材料归并为40份。并经生产力鉴定,筛选出“瑞丽紫红皮”、“普洱黄山芋”等一批具有推广潜力的优良地方品种,可在云南省甘薯生产上逐步推广使用。