Crystal structure of lipoprotein GNA1946 from Neisseria meningitidis

GNA1946, a conserved outer membrane lipoprotein from Neisseria meningitidis, has been identified as a candidate antigen for an urgently needed broad-spectrum meningococcal vaccine. It has been predicted to be a periplasmic receptor in the d-methionine uptake ABC transporter system. The crystal structure of GNA1946 was solved by the single-wavelength anomalous dispersion (SAD) method to a resolution of 2.25 Å, and it reveals a Venus flytrap-like structure. GNA1946 consists of two globular lobes connected by a hinge region. Surprisingly, the structure showed an l-methionine bound within the cleft between the lobes. A comparison of GNA1946 with two other outer membrane lipoproteins, the l-methionine-binding Tp32 from Treponema pallidum and the dipeptide GlyMet-binding protein Pg110 from Staphylococcus aureus, revealed that although these three proteins share low sequence similarities, there is a high degree of structural conservation and similar substrate-binding frameworks. Our results reveal that GNA1946 is an l-methionine binding lipoprotein in the outer membrane, and should function as an initial receptor for ABC transporters with high affinity and specificity. The GNA1946 structure reported here should provide a valuable starting point for the development of a broad-spectrum meningococcal vaccine.     

重组人生长激素对梗阻性黄疸大鼠sIgA、EGF的影响

目的：观察重组人生长激素对梗阻性黄疸大鼠sIgA、EGF的影响。方法：Wistar大鼠60只随机分4组（n=15）：假手术对照组（A组）、胆总管结扎组（B组）、胆总管结扎＋rhGH治疗1周组（C组）、胆总管结扎＋rhGH治疗2周组（D组）。除A组外,其余各组将胆总管结扎,致胆总管完全梗阻。A组和B组术后2周处死大鼠;C组于术后开始,在双后肢内侧轮流皮下注射rhGH 0.75U.kg^-1.d^-1,1周后处死;D组于术后开始,在双后肢内侧轮流皮下注射rhGH 0.75U.kg^-1.d^-1,2周后处死。各组均无菌操作,在麻醉成功后开腹直视下获取标本,测定TB、ALP、PA、IGF-I、sIgA、EGF等。结果：大鼠梗阻性黄疸时,B、C、D组血中PA、IGF-I及胃肠液中sIgA、EGF降低,血中TB、ALP升高,与A组比较均具有显著性差异（P〈0．05）;而给予外源性生长激素的c组、D组胃肠液中sIgA、EGF降低幅度明显低于B组（P〈0．05）,且梗阻性黄疸大鼠细菌移位率也明显低于B组。结论：外源性生长激素,能保护梗阻性黄疸大鼠的肝脏功能,以及肠道的机械屏障功能和免疫屏障功能,减少肠道细菌移位的发生。     

Improved <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated genetic transformation of GNA transgenic sugarcane

Six plasmids carrying a snowdrop lectin (Galanthus nivalis agglutinin, GNA) and one of three selection markers were successfully transferred into two sugarcane cultivars (FN81–745 and Badila) via Agrobacterium-mediated transformation. Agrobacterium strains LBA4404, EHA105 and A281 that harboured a super-binary vector were used for sugarcane transformation. The use of the hygromycin (Hyg) resistance gene (hpt II), phosphinothrincin (PPT) resistance gene (bar) or G418 resistance gene (npt II) as a screenable marker facilitated the initial selection of GNA transgenic sugarcane callus with different efficiencies and helped the rapid segregation of individual transformation events. All the three selective marker genes were controlled by CaMV 35S promoter, while GNA gene was controlled by promoter of RSs-1 (rice sucrose synthase-1) or Ubi (maize ubiquitin). Factors important to successful transformation mediated by Agrobacterium tumefaciens were optimized, which included concentration of A. tumefaciens, medium composition, co-cultivated methods with plant tissue, strain virulence and different selective marker genes. An efficient protocol for sugarcane transformation mediated by A. tumefaciens was established. The GNA gene has been integrated into sugarcane genome as demonstrated by PCR and Southern dot blotting detections. The preliminary results from bioassay demonstrated a significant resistance of the transgenic sugarcane plants to woolly aphid (Ceratovacuna lanigera Zehnther) indicating thus the possibility for obtaining a transgenic sugarcane cultivar with resistance to woolly aphid.     

Quantification of glucosinolates in leaves of leaf rape (Brassica napus ssp. pabularia) by near-infrared spectroscopy

The potential of near-infrared spectroscopy (NIRS) for screening the total glucosinolate (t-GSL) content, and also, the aliphatic glucosinolates gluconapin (GNA), glucobrassicanapin (GBN), progoitrin (PRO), glucoalyssin (GAL), and the indole glucosinolate glucobrassicin (GBS) in the leaf rape (Brassica napus L. ssp. pabularia DC), was assessed. This crop is grown for edible leaves for both fodder and human consumption. In Galicia (northwestern Spain) it is highly appreciated for human nutrition and have the common name of "nabicol". A collection of 36 local populations of nabicol was analysed by NIRS for glucosinolate composition. The reference values for glucosinolates, as they were obtained by high performance liquid chromatography on the leaf samples, were regressed against different spectral transformations by modified partial least-squares (MPLS) regression. The coefficients of determination in cross-validation (r2) shown by the equations for t-GSL, GNA, GBN, PRO, GAL and GBS were, respectively, 0.88, 0.73, 0.81, 0.78, 0.37 and 0.41. The standard deviation to standard error of cross-validation ratio, were for these constituents, as follows: t-GSL, 2.96; GNA, 1.94; GBN, 2.31; PRO, 2.11; GAL, 1.27, and GBS, 1.29. These results show that the equations developed for total glucosinolates, as well as those for gluconapin, glucobrassicanapin and progoitrin, can be used for screening these compounds in the leaves of this species. In addition, the glucoalyssin and glucobrassicin equations obtained, can be used to identify those samples with low and high contents. From the study of the MPLS loadings of the first three terms of the different equations, it can be concluded that some major cell components as protein and cellulose, highly participated in modelling the equations for glucosinolates.     

Uveal melanoma driver mutations in GNAQ/11 yield numerous changes in melanocyte biology

Uveal melanoma (UM) is the most common primary intraocular cancer and has a high incidence of metastasis, which lacks any effective treatment. Here, we present zebrafish models of UM, which are driven by melanocyte‐specific expression of activating GNAQ or GNA11 alleles, GNAQ/11^Q209L, the predominant initiating mutations for human UM. When combined with mutant tp53, GNAQ/11^Q209L transgenics develop various melanocytic tumors, including UM, with near complete penetrance. These tumors display nuclear YAP localization and thus phenocopy human UM. We show that GNAQ/11^Q209L expression induces profound melanocyte defects independent of tp53 mutation, which are apparent within 3 days of development. First, increases in melanocyte number, melanin content, and subcellular melanin distribution result in hyperpigmentation. Additionally, altered melanocyte migration, survival properties, and evasion of normal boundary cues lead to aberrant melanocyte localization and stripe patterning. Collectively, these data show that GNAQ/11^Q209L is sufficient to induce numerous protumorigenic changes within melanocytes.     

雪花莲外源凝集素基因转化番茄

The plasmid pRSSGNA1 carried a snowdrop lectin gene (Galanthus nivalis agglutinin, GNA) under the drive of RSs-1 promoter, were successfully transferred into three tomato (Lycopersicon esculentum Mill.) cultivars, “C8”,“A39” and “A53” via Agrobacterium-mediated transformation. Regenerated plantlets were obtained from cotyledons after preculture, shoot inducing culture and root inducing culture. Transgenic tomato plants were confirmed by the kanamycin-resistant experiment, PCR analysis and Southern blot. The preliminary results from bioassay demonstrated significant resistance of the transgenic plants to aphid (Myzus persicae Sulzer) larvae. The inheritance of selective marker gene (NPTⅡ) in 3 transgenic tomato plants is in the model of the simple Mendel's fashion in progenies of the selfing generation.     

A chromosome-specific sequence common to the B genome of polyploid wheat and Aegilops searsii

A low-copy, non-coding chromosome-specific DNA sequence, isolated from common wheat, was physically mapped to the distal 19% region of the long arm of chromosome 3B (3BL) of common wheat. This sequence, designated WPG118, was then characterized by Southern hybridization, PCR amplification and sequence comparison using a large collection of polyploid wheats and diploid Triticum and Aegilops species. The data show that the sequence exists in all polyploid wheats containing the B genome and absent from those containing the G genome. At the diploid level, it exists only in Ae. searsii, a diploid species of section Sitopsis, and not in other diploids including Ae. speltoides, the closest extant relative to the donor of the B genome of polyploid wheat. This finding may support the hypothesis that the B-genome of polyploid wheat is of a polyphyletic origin, i.e. it is a recombined genome derived from two or more diploid Aegilops species.