不同光源对4种蔬菜幼苗叶绿素荧光及生理指标的影响

为了解不同光源或光源组合对茄子、辣椒、番茄、黄瓜幼苗叶绿素荧光及生理指标的影响,在4种基本光源的基础上,比较了不同光源处理下不同蔬菜植株叶片的叶绿素荧光参数、可溶性蛋白和可溶性糖含量。结果表明:红蓝光源不利于4种蔬菜幼苗叶片光合色素的形成,茄子、辣椒、番茄和黄瓜叶片中的光合色素含量分别在2白4红2黄、3白3红2黄、8黄或8红、8白光源下最高;茄子和番茄幼苗叶片在红蓝光源下,辣椒和黄瓜在3白3红2黄光源下,最大光化学效率和实际光化学效率都最大;茄子和辣椒幼苗在红蓝光源下所受非生物胁迫最小,叶片中可溶性蛋白含量最低,而番茄和黄瓜分别在3白3红2黄和8白光源下的可溶性蛋白含量最低;红蓝光源可明显增加4种蔬菜幼苗叶片的可溶性糖含量,对幼苗的形态建成有积极的影响。在冬春季蔬菜育苗生产中,可根据不同光源优势为不同种类蔬菜组配光源,以促进幼苗生长发育。     

Identification of resistance to Aspergillus flavus infection in cotton germplasm

Natural resistance in cottonseed to Aspergillus flavus infection has not been explored to date. A green fluorescent protein (GFP) expressing A. flavus strain was used to assess the resistance of seed from 35 cotton varieties from Gossypium arboreum, G. barbadense, and G. hirsutum. Mature cotyledons devoid of seed coat were wounded, inoculated, and assessed for innate resistance to A. flavus infection. Of the initial 35 varieties tested, we observed a range of resistance to infection in representatives of all three species. A subset of 15 representatives was further analyzed. Within this group, G. arboreum cultivar A2 186 and G. hirsutum cultivar SA 1582 were most resistant to fungal infection. The most susceptible cultivar in this group was G. hirsutum SA 1595. The remaining 12 representatives tested in the secondary screen (3 G. arboreum, 3 G. barbadense, and 6 G. hirsutum lines) exhibited intermediate resistance. We did not observe any relationship between species and resistance. Within each species, there was a range of responses to fungal infection. Future studies using this methodology to screen additional diploid and tetraploid cotton lines may enable us to identify naturally resistant germplasm that can be used to develop cotton with enhanced resistance to fungal infection.     

昆虫嗅觉相关蛋白的研究进展

昆虫对自然环境中复杂化学信号的识别多依赖于其灵敏的嗅觉系统,选择寄主、觅食、寻找配偶等行为的发生都以嗅觉识别为基础,而完成嗅觉识别还需要多种嗅觉相关蛋白的参与。嗅觉相关蛋白主要包括6种,即气味结合蛋白、化学感受蛋白、气味受体、感觉神经元膜蛋白、离子型受体和气味降解酶。不同种类和性别的昆虫中,嗅觉蛋白的种类、数量和分布各不相同。由于嗅觉蛋白在昆虫识别外界气味分子中的重要作用,国内外近年来对其展开了广泛、深入的研究。本文从几种嗅觉相关蛋白的生化特性、分子结构、生理功能、分布表达部位和研究概况等角度,较详细地综述了近年来国内外昆虫嗅觉相关蛋白的研究进展。     

大豆RING/U-box蛋白Glyma.13G115900的克隆及其对非生物胁迫的应答

课题组前期对干旱胁迫下大豆转录组的数据分析发现大豆Glyma.13G115900基因编码一个RING/U-box蛋白,其表达水平受干旱胁迫影响显著。本研究以垦丰16大豆为试验材料,克隆Glyma.13G115900基因。氨基酸多重序列比对表明其编码的蛋白与其它物种都具有高度保守的RING/U-box结构域。构建原核表达载体pET-29b-Glyma.13G115900转化到大肠杆菌中,Glyma.13G115900蛋白在大肠杆菌中能够表达。荧光定量PCR分析表明Glyma.13G115900基因的表达量受PEG、NaCl和ABA的影响显著,但基本不受冷胁迫的诱导。经PEG和NaCl处理后,该基因表达量与CK相比呈现出显著下降的趋势,PEG处理的表达量变化比NaCl下调的更明显;在ABA诱导下与CK相比该基因的mRNA丰度呈现出先上升后下降的趋势,在4 h表达量出现峰值,推测该基因可能通过依赖于ABA途径参与非生物胁迫应答。以上结果为进一步深入研究该基因的调控途径奠定基础。     

水稻齿叶矮缩病毒Pns10蛋白在水稻原生质体内的表达

【目的】水稻齿叶矮缩病毒(Rice ragged stunt virus,RRSV)Pns10蛋白在介体昆虫细胞内可形成类似病毒原质(viroplasm)的内含体,是RRSV侵染介体所必需。然而Pns10蛋白在水稻寄主中是否具有类似功能及其表达情况如何未见报道。【方法】利用大肠杆菌系统表达Pns10蛋白,免疫家兔制备多克隆抗体;通过水稻原生质体病毒侵染体系,利用免疫荧光技术分析Pns10蛋白在水稻原生质体内的分布情况,利用实时定量PCR技术和Western blot技术分别检测Pns10 RNA和Pns10蛋白在水稻原生质体内的积累情况。【结果】将Pns10基因克隆到Gateway系统原核表达载体p DEST17中,IPTG诱导表达成功后,制备融合蛋白抗血清。Western blot检测显示,该抗血清可检测感病水稻叶片中的Pns10蛋白。病毒侵染水稻原生质体后,Pns10蛋白可形成类似病毒原质的内含体;Pns10 RNA在病毒接种8 h后开始积累,24 h后达到最大值,随后开始下降;Pns10蛋白在24 h后开始表达,之后维持较高水平,60 h后略有下降。【结论】成功获得了Pns10抗血清;Pns10在水稻原生质体内成功表达,可形成类似病毒原质的内含体,并且Pns10 RNA的表达先于其蛋白的表达。     

Characterization of Spray-Dried Hydrolyzed Proteins from Pink Perch Meat Added with Maltodextrin and Gum Arabic

In the present study, spray-dried pink perch meat protein hydrolysate (PPH) and hydrolysate with maltodextrin and gum arabic (PPHMG) were characterized in relation to their physical, rheological, functional, antioxidant, thermal, and sensory properties. The Herschel–Bulkley model was suitable to explain the flow behavior of PPH and PPHMG emulsions. Both the samples exhibited functional and antioxidant properties. Antioxidant activities were significantly higher for PPH compared with PPHMG (p<0.05). PPH and PPHMG alone did not exhibit antimicrobial activity but enhanced the activity of chitosan against pathogens. Sensory acceptability of the samples in soup revealed that PPHMG of up to 4% was highly scored without any traces of bitterness, whereas for PPH, a concentration of up to 3% was acceptable.     

Carbohydrate and crude protein fractions in perennial ryegrass as affected by defoliation frequency and nitrogen application rate

The objective of this study was to evaluate the effects of defoliation frequency (either at two‐ or three‐leaf stage) and nitrogen (N) application rate (0, 75, 150, 300, 450 kg N ha^?1 year^?1) on herbage carbohydrate and crude protein (CP) fractions, and the water‐soluble carbohydrate‐to‐protein ratio (WSC:CP) in perennial ryegrass swards. Crude protein fractions were analysed according to the Cornell carbohydrate and protein system. Carbohydrate fractions were analysed by ultra‐high‐performance liquid chromatography. Sward defoliation at two‐leaf stage increased the total CP, reduced the buffer‐soluble CP fractions and decreased carbohydrate fractions of herbage (P < 0·001). The effect of defoliation frequency was less marked during early spring and autumn (P < 0·001) than for the rest of the seasons. An increase in N application rate was negatively associated with WSC, fructans and neutral detergent fibre (P < 0·001), and positively associated with CP and nitrate (N‐NO₃) contents of herbage. Nitrogen application rate did not affect CP fractions of herbage (P > 0·05). The fluctuations in CP and WSC contents of herbage resulted in lower WSC:CP ratios during early spring and autumn (0·45:1 and 0·75:1 respectively) than in late spring (1·11:1). The herbage WSC:CP ratio was greater (P < 0·001) at the three‐leaf than the two‐leaf defoliation stage and declined as the N application increased in all seasons (P < 0·001). The results of this study indicate that CP and carbohydrate fractions of herbage can be manipulated by sward defoliation frequency and N application rate. The magnitude of these effects, however, may vary with the season.     

Effect of different feeds on the growth,survival and reproductive performance of zebrafish,Danio rerio (Hamilton, 1822)

Present experiment was conducted to determine the effect of different feeds with varying protein levels on the growth, survival and reproductive performance of zebrafish, Danio rerio. The control diet (T1) was wild‐collected zooplankton from local fish ponds, while test diets with 350 g kg^?1 protein (T2), 400 g kg^?1 protein (T3) and 450 g kg^?1 protein (T4) were formulated and fed to fish for a period of 210 days. The significantly (P < 0.05) highest mean weight gain and specific growth rate were observed in T1, which were similar with T3 and T4. The significantly (P < 0.05) highest number of egg production per female and relative fecundity were found in T1, followed by T4 and T3 while T2 produced lowest number of eggs. No significant (P > 0.05) differences were observed in brood survival rate, fertilization and hatching rate among the dietary treatments. The highest (P < 0.05) fry survival rate was recorded in T1, followed by T3 and T4. Thus, it is suggested that control diet i.e. mixed zooplankton exhibited better growth, reproductive performance and fry survival rate. However, diet containing 400 g kg^?1 crude protein also gave comparable results in terms of growth, survival and reproductive performance of zebrafish.     

Impacts of diet on hindgut microbiota and short‐chain fatty acids in grass carp (Ctenopharyngodon idellus)

Diet is known to influence intestinal microbiota in fish, but the specifics of these impacts are still poorly understood. Different protein/fibre ratio diets may result in differing structures and activities of gut microbiota. We examined the hindgut microbiome of grass carp (Ctenopharyngodon idellus) fed three different diets: fish meal (FM, high protein – low fibre), Sudan grass (SG, high fibre – low protein) and compound feed (CF, intermediate). Microbial profiles of fish fed on FM were significantly different from profiles of fish fed CF and SG (F = 18.85, p < .01). Cetobacterium, known to be positively associated with protein digestion, was the dominant microbial group in FM samples (approximately 75.7%), while Lachnospiraceae and Erysipelotrichaceae, thought to be involved in fermentation of plant polysaccharides, were dominant in CF and SG samples (46.8% and 42.9% respectively). Network analyses indicated that the abundance of Lachnospiraceae and Erysipelotrichaceae was in a significantly positive correlation (r = .895, p = .001). Short‐chain fatty acid (SCFA) levels may indicate that the digestibility of diet by microbiota in the grass carp gut decreased from FM to SG (FM>CF>SG). Overall low SCFA levels indicate that hindgut fermentation probably provides a low proportion of energy requirements in grass carp.     

Characteristics and Functional Properties of Ovary from Squid Loligo Formosana

The characteristics and functional properties of the ovary from Loligo formosana were studied. Moisture (72.07 ± 0.24%) was dominant, followed by protein (18.64 ± 0.51%) and carbohydrate (7.44 ± 0.2%). Ash (1.39 ± 0.03%) and lipids (0.46 ± 0.5%) were found as the minor constituents. Albumin (79.02 ± 0.79%) was the major protein of the squid ovary, followed by glutelin-1 (8.31 ± 0.62%) and globulin (6.68 ± 0.08%). Nevertheless, prolamin and glutelin-2 constituted approximately 1% of the total proteins. Based on the electrophoretic studies, albumin had the largest band intensity. The squid ovary was rich in non-essential amino acids (52.26%) and high in hydrophobic amino acids (48.03%). It was also rich in polyunsaturated fatty acid (PUFA, 43.76 ± 0.84%), followed by saturated fatty acid (SFA, 39.36 ± 0.12%) and monounsaturated fatty acid (MUFA, 12.94 ± 0.55%). Ovary lipids had a high amount of docosahexaenoic acid (C22:6) (28.59%). At pH 3, the squid ovary powder (SOP) had the maximum solubility (96.39%), whereas the lowest solubility (38.33%) was observed at pH 9. The foaming capacity and stability of SOP were increased with increasing concentration up to 8% (p < 0.05). The globulin fraction showed the higher foaming capacity, as compared to albumin and glutelin-1 fractions. The squid ovary had good nutritional value and possessed excellent foaming properties. Therefore, the squid ovary could serve as a novel food additive or ingredient.