976 resultados para Insect pectinase


Relevância:

10.00% 10.00%

Publicador:

Resumo:

植物与传粉者的关系并非一门独立的学科,它包含很多进化生物学的内容。传粉生物学研究为我们理解植物进化的一些关键问题,如生殖隔离、物种形成、适应进化等提供重要证据。兰科植物由于其精巧的花部结构及其独特的传粉机制,备受传粉生物学家的关注。从达尔文时代以来,有大量的文献记载了欧洲兰族植物的传粉生物学的各个方面,其中,共涉及4种欺骗性传粉方式,它们几乎代表了兰科植物中近1/3没有报偿兰花所有的欺骗类型。然而,到目前为止,尽管在中国有丰富的兰族植物资源,中国兰科植物的传粉生物学研究仍然很缺乏。 在本研究中,作者以黄龙自然保护区内兰族的2种根茎兰属植物和1种小蝶兰属植物为材料,研究它们的传粉生物学,并探讨他们之间的生殖隔离机制。 1. 根茎兰属Galearis 及小蝶兰属Ponerorchis植物的交配系统 所研究的2种根茎兰属植物和1种小蝶兰属植物人工自交授粉均可以成功结实。在自然条件下,广布小蝶兰和二叶根茎兰都必须依赖于昆虫才能结实成功,而黄龙根茎兰则是以自花授粉为主。 2. 广布小蝶兰Ponerorchis chusua的传粉系统 在黄龙自然保护区进行了连续2 年的野外观测和实验,结果表明,广布小蝶兰是一种自交亲和,但需要昆虫传粉的欺骗性植物。广布小蝶兰的主要传粉者为雌性Bombus rufofasciatus,雌性B. consobrinus wittenburg,B. cucorun的蜂王和雄性B. pyrosona。熊蜂对广布小蝶兰具有典型的欺骗性兰花传粉的特征,即访问十分迅速,并且一般一个植株只访问一朵花,避免了同株异花授粉。 3. 二叶根茎兰Galearis diantha的传粉系统 野外观察表明,二叶根茎兰只有一种有效的传粉者,其访问频率不高,访 问时间短,并且会一次访问一个植株的两朵花,不可避免的产生同株异花授粉。自然结实率为23.0-26.8%,人工授粉实验证明传粉者限制是结实率较低的主要原因。 4. 黄龙根茎兰Galearis huanglongensis的传粉系统 研究结果表明,黄龙根茎兰为自动自花授粉的植物,黄龙根茎兰的花粉约在花开放4天后,花粉块从花粉囊中掉出,由于重力作用,花粉块柄弯曲使花粉接触到柱头,完成传粉。 5. 根茎兰属Galearis及小蝶兰属Ponerorchis植物的生殖隔离机制 本文的研究表明,根茎兰属内的杂交及与小蝶兰属间植物之间人工杂交授粉均可以成功结实,它们物种之间的生殖隔离主要是通过受精前隔离机制。具有相同传粉者(B. rufofasciatus)的广布小蝶兰与二叶根茎兰通过机械隔离机制保持物种界限。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本文通过根农杆菌(Agrobacterium tumfaciens)介导法分别将Signal和KDEL修饰的豇豆胰蛋白酶抑制剂(Cowpea trypsin inhibitor, CpTI)基因、豌豆外源凝集素(Pea lectin, P-Lec)和大豆Kunitz型胰蛋白酶抑制剂(Soybean Kunitz typsin inhibitor, SKTI)双价抗虫基因、雪花莲外源凝集素(Galanthus nivals agglutinin, GNA)基因以及高效复合启动子OM控制的苏云金杆菌(Bacillus thuringiensis, B.t.)杀虫毒蛋白基因导入了陆地棉(Gossypium hirsutum L.)栽培品种新陆早1号、新陆中2号、晋棉7号、冀合321、辽9和晋棉12号,并获得了大批转基因再生植株。 实验中对影响棉花转化和再生的一些条件进行了研究,从根农杆菌培养、棉花无菌苗的制备、转化操作和共培养等方面对转化条件进行了探讨;从激素配化、植物表达载体、外植体类型、基因型等方面对抗性愈伤组织的诱导进行了摸索;从激素、从碳源、培养容器、pH值、抗褐化剂及固化剂的选择等方面对影响植株再生的条件进行了优化。 本文开创性地采用嫁接代替移栽,从而极大地提高了转化植株定植成活率,缩短了缓苗时间并增加了转化植株当代的繁殖系数。 在建立了一套较为高效的陆地棉转化及再生系统基础上,本文还进行了其它转化方式和转化体系的初步探讨。利用棉花幼嫩种子无菌苗下胚轴作为外植体,通过改变愈伤组织诱导培养基配方面提高胚性愈伤组织的诱导频率,进而得到更多的体细胞胚状和再生植株,缩短再生周期;尝试用胚性愈伤组织作为外植体的根农杆菌介导法转化,确定了一些与转化有关的条件;建立了一套棉花茎尖培养程序,为运用基因枪法轰击棉花茎尖分生组织或用根农杆菌直接转化茎尖分生组织,以克服根农杆菌转化棉花时体胚发生的基因型局限开辟了一条新途径。 本文还建立了一种快速鉴定转化植株后代的方法。这一简便方法还有助于进行转基因棉纯合系的筛选以及外源基因的遗传稳定性研究。 转基因植株经Npt-II ELISA、PCR、PCR Southern 检测证明外源抗虫基因CpTI、SKTI、P-lec、GNA以及B.t.基因已存在于转化植株基因组内。修饰的CpTI转基因植株抗棉铃虫(Heliothis armigera Hubner)试验结果表明,其杀虫效果显著优于前期未修饰的CpTI转化植株。P-lec和SKTI双价转基因植株抗棉铃虫试验结果表明,转基因植株对棉铃虫幼虫具有较强的杀虫活力。 目前,已获得转以上抗虫基因棉花T1代植株。为今后进一步将植物基因工程技术应用于棉花遗传改良打下了基础。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

以陆地棉(Gossypium hirsutum L.)栽培品种新陆早4号、系550、冀资492、衡无89-30、邯93-2、冀资123等为材料,进行了组织培养及植株再生研究,建立了一套陆地棉体细胞植株再生速成体系。通过调整激素种类与比例以及改善培养条件,降低了畸形胚发生频率(从80%降为41%),并可将畸形苗转化为正常苗(转化率约为78%);通过水培和嫁接,结合试管扦插、扩繁技术,解决了棉花生根及移栽难题,为农杆菌介导法转化棉花奠定了基础。 用绿色荧光蛋白基因(gfp)作为报告基因,构建了pBGb1m(含Bt和gfp二价基因)、pBGbf(含Bt-gfp融合基因)和pBGbfg(含Bt-gfp融合基因和gna基因)等三种植物表达载体。通过农杆菌介导法转化烟草,转基因再生植株经过荧光、虫试、PCR、Southern blot和Western blot等检测,表明三种植物表达载体能够在转基因植物中有效表达,同时,绿色荧光蛋白(GFP)的检测表现出了简便、经济、快速、可靠等优点,为大量棉花转基因苗的检测提供了一种有效方法。 采用花粉管通道法将携带细胞间隙定位信号肽的Bt基因的pBin438-S1m质粒导入棉花品种冀资492,经过田间卡那霉素筛选、虫试、PCR、PCR-Southern blot和Southern blot检测,证明Bt基因已整合至棉花基因组中,而且可能是以单拷贝形式插入。 同时,通过农杆菌介导法将三种植物表达载体(pBGb1m、pBGbf和pBGbfg)转化陆地棉栽培品种新陆早4号、冀资492、衡无89-30和邯93-2等材料,获得了大量转化再生棉株。经过PCR和PCR-Southern blot检测,转基因阳性植株为转为再生植株总数的89.45%。目前,虫试、Southern blot及Western blot正在进行之中。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

EXTRACT (SEE PDF FOR FULL ABSTRACT): We argue that the most important climatically-driven terrestrial ecosystem changes are concentrated in annual- to decadal-scale episodic events. These rapid ecosystem responses to climate change are manifested as regionally synchronized disturbance events (eg, floods, fires, and insect outbreaks) and increased drought-caused plant mortality rates.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The food and feeding habits of an air-breathing fish, Heteropneustes fossilis were studied from an eutrophic lake, Hussainsagar, Hyderabad, (Andhra Pradesh, India), during 1981-1983. The major preferred items of food were insect larvae, insects, ostracods, plant material and gastropods. Due to the mixed feeding habits of both plant and animal matter, this species is considered as an omnivorous feeder. Bryozoans were recorded for the first time in the diet of H. fossilis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

植物与昆虫的互作关系是个长期进化的过程,虫害给农业生产带来巨大损失。本研究以甘蓝型油菜(Brassica napus)为例,研究了不同环境条件和遗传背景下外源基因的表达与效用,同时利用蛋白质组技术,研究了虫害损伤模拟条件下植物可能存在的内源抗性机制。甘蓝型油菜中转入了人工合成的Bt(Bacillus thuringiensis)杀虫基因,能使植物产生抗虫蛋白抵御虫害。我们在湖北湖南两个实验点进行了大田实验,按植株生长发育的4个不同时期从转基因植株的叶片上采样,研究抗虫蛋白在植物体内的表达动态。植株顶部第三片展开叶的Bt毒蛋白浓度在结荚期前随植物生长而不断增加,而在结荚期出现或增或减的现象。采样叶片的可溶性总蛋白浓度含量一直呈增加的趋势,直到结荚以后出现含量的明显降低。同时,收集了转基因油菜与湘油15号在田间自然杂交形成的杂交后代种子用于栽培,用GFP仪检测杂交后代的绿色荧光蛋白(green fluorescent protein),并用聚合酶链式反应(polymerase chain reaction, PCR)检测并确认带有转基因的杂交植株。为了检测带有转基因的杂交后代油菜中Bt毒蛋白的杀虫效率,用对Bt毒蛋白敏感的试虫品系——初孵棉铃虫幼虫(Helicoverpa armigera)进行杀虫活性检测实验。结果表明,携带Bt基因的杂交湘油及其转基因亲本对试虫的体重增长量均产生了负面影响,可以推断在调查取样的植株生长发育阶段,转基因杂交后代与其转基因亲本植株的杀虫效率没有显著差异。转基因植物及其杂交后代中抗虫蛋白的持续表达及田间带有转基因的自播植物的出现会使害虫产生耐受抗性的潜在可能性增加。 相对于人为增加的抗虫基因,植物在长期对抗昆虫的过程中也进化形成了自我防御机制,能够产生特异的抗性蛋白来应对昆虫的取食。本研究用机械损伤模拟害虫取食,对比了油菜受到物理损伤前后可溶性总蛋白的含量变化并试图通过蛋白质组学技术来检测可能发生变化的蛋白质。Bradford定量测定发现,同一植株同一叶片损伤前后可溶性总蛋白含量差异显著,损伤后蛋白表达量显著增高。蛋白质组双向凝胶电泳及其差异分析显示,损伤前后有8个蛋白质点发生明显的上调或下调。选择其中2个差异蛋白点经过MALDI-TOF质谱鉴定,它们分别是Rubisco小亚基前体以及果糖-1,6-二磷酸醛缩酶和粪卟啉-3-氧化酶的混合物,这些蛋白质在其他植物的抗逆研究中也有报道,它们可能在油菜叶片应答机械损伤过程中对维持植物的生理功能也有重要作用。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A study was conducted to evaluate the quality aspects of eight exportable dried fishery products of Bangladesh. The products were evaluated by examining organoleptic properties, water reconstitution behavior, microbiological and biochemical aspects. The water reconstitution rate was faster in ribbon fish and Bombay duck, and slower in other fishes and air bladder and shark fin products. Organoleptic and physical characteristics in respect of color, odor, texture, insect infestation and broken pieces of the products revealed that all of the products were either in excellent or acceptable condition. Total viable bacterial load ranged from 0.95 x 104 CFU/g to 1.8 x 104 CFU/g in dried products. Coliform bacteria was absent in all the dried fishery products. The results of moisture, crude protein, lipid and ash content of the products ranged from 16.20 to 23.51%, 58.37 to 82.86%, 0.17 to 14.44% and 0.58 to 9.23%, respectively. Non-protein nitrogen (NPN) contents were in the range of 0.104 to 2.372% and the pepsin digestibility values were of 88.41 to 94.23%. The results of the study suggested that the exportable dried products were of good quality and hygienically safe.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Paddy fields can be broadly classified on the basis of land situations viz. Upland - Shallow water (10-30 cm), Medium land-medium deepwater (30-100 cm) and Low land-deepwater (above 100 cm). Three major systems of paddy-cum-fish culture, viz. (A) high yielding paddy varieties (H.Y.V) and air-breathing fish under Upland, (B) H.Y.V./local paddy and Tilapia/common carp under Medium land and (C) deepwater paddy and major Indian carps under Low land situations have been successfully investigated in the farmers' fields and at the Research Stations (1982-92). Effects of low-cost artificial feeding on growth, yield and management practices of different types of fish showed a considerable increase of rice and fish yields and a decrease in insect-pest incidence. Under Upland situation, short duration H.Y.V. in combination with fast-growing air breathing fish was studied thrice a year (summer, winter & autumn seasons). Combined rice and fish culture produced highest yields in all the seasons than in the control.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Three nematodes, two acanthocephalans and three cestodes were collected by dissecting 15 species of fish. Of these parasites only Hedruris sp. a larval nematode is responsible directly for the death of fish, since it is found in predatory species a reduction of these might prove of considerable consequence to fish, production. Bothriocephalus gowleonensis, a cestode probably introduced from China with Chinese carp, was recorded in an indigenous carp Puntius sarana. This parasite causes heavy mortality in grass carp in China and is a potential danger to local species. A single crustacean parasite was recorded. It is likely that they are widespread. No protozoa were recorded but there can be little doubt that they occur in local freshwater species and may be of considerable importance in fisheries. Several predators (insects, fish and other vertebrates) were recorded and are doubtless of considerable importance. However, the role of parasites and of predators (especially fishes) in relation to the productivity of fisheries can hardly be assessed at present and needs further study. A study of the fauna found at the shallow edges of 21 irrigation reservoirs showed an abundance of fauna in the low-country reservoirs whilst the up-country reservoirs had a poor fauna. The fauna showed insects, crustacea and mollusca in this order of abundance. The presence of insect and molluscs feeding fish in our fauna shows that these rich sources of food are being utilised.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present study deals with the chemical, algal and faunal characteristics of the stream system at Horton Plains, the highest plains in Ceylon (altitude 2'225 m). The cultivation of seed potatoes and subsequent use of fertilizers have caused extensive silting and severe eutrophication of the stream systems. Since there are no indigenous fish, the trout Salmo gairdnerii has been introduced and it is the only fish found in these streams. The commonest fauna in the streams are crabs (Paratelphusa sp.), shrimps (Caridimr sp.), Simulium sp. and Chironomus sp. Their increase in number is probably correlated with increase in organic and detritus matter. The most important food items of the trout are the crabs living abundantly in the stream, insect larvae and terrestrial insects were also commonly found in the guts. Records of stocking and taking of trout in the Horton plains streams have shown that now less trout are taken relatively to the numbers stocked. This decrease may be possibly due to the eutrophication of the stream and also due to the possible use of pollutants in connection with the cultivation of seed potatoes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A quality of survey was conducted at the fish curing yards in a northwest coast and the southern coast in Sri Lanka. A total of 40 samples different varieties of fishes were collected from the market and jaadi curing yards and all were evaluated for the quality, fungal and insect infestation. Samples were analyzed for proximate composition chemical, microbiological and sensory quality. Thirty percent of the total analyzed samples of fish were found to be unfit for consumption. Samples collected from Negombo were found to the infected with maggots. Only 42% samples had dry matter above 50%. All the samples showed a protein content above 20%. The highest protein content was 27.92% in hurulla. Over 90% of the samples had TVN at acceptable quality limits (>40). The TBC for 33% of the samples were in the range 104-105/g range, while 48% were in the range of 107-108/g due to contamination of maggots and fungi. The Survey showed jaadi had a high level of protein in its composition. But defects of curing process such on imperfect cleaning inadequate salting resulted in low (Chemical and microbiological) quality of the product.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

:昆虫体内形成了强大的免疫肪御系统,其被各种微生物攻击时能依靠病原相关分子模式识别蛋白时 感染进行区分和激活体内信号通路诱导如抗茵肤之类的效应分子昆虫体内控雠先天性免疫的信号通路分 别是.T01l通路、IMD通路和JAS/sTAT通路,这3条通路在信号传递过程中存在协作,井且,这些通路与脊椎 动物体内某些通路存在惊人相似、在免疫调控通路方面存在共同的进化起源.遣揭示了先天性免疫在动物体 内存在的普遍-胜和机体抵御病原感染的重要性.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Like large insects, micro air vehicles operate at low Reynolds numbers O(1; 000 - 10; 000) in a regime characterized by separated flow and strong vortices. The leading-edge vortex has been identified as a significant source of high lift on insect wings, but the conditions required for the formation of a stably attached leading-edge vortex are not yet known. The waving wing is designed to model the translational phase of an insect wing stroke by preserving the unsteady starting and stopping motion as well as three-dimensionality in both wing geometry (via a finite-span wing) and kinematics (via wing rotation). The current study examines the effect of the spanwise velocity gradient on the development of the leading-edge vortex along the wing as well as the effects of increasing threedimensionalityby decreasing wing aspect ratio from four to two. Dye flow visualization and particle image velocimetry reveal that the leading-edge vortices that form on a sliding or waving wing have a very high aspect ratio. The structure of the flow is largely two-dimensional on both sliding and waving wings and there is minimal interaction between the leading-edge vortices and the tip vortex. Significant spanwise flow was observed on the waving wing but not on the sliding wing. Despite the increased three-dimensionality on the aspect ratio 2 waving wing, there is no evidence of an attached leading-edge vortex and the structure of the flow is very similar to that on the higher-aspect-ratio wing and sliding wing. © Copyright 2010.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Ag5 proteins are the most abundant and immunogenic proteins in the venom secretory ducts of stinging insects. An antigen 5-like protein (named tabRTS) composed of 221 amino acid residues was purified and characterized from the salivary glands of the horsefly, Tabanus yao (Diptera, Tabanidae). Its cDNA was cloned from the cDNA library of the horsefly's salivary gland. TabRTS containing the SCP domain (Sc7 family of extracellular protein domain) was found in insect antigen 5 proteins. More interestingly, there is an Arg-Thr-Ser (RTS) disintegrin motif at the C-terminus of tabRTS. The RTS motif is positioned in a loop bracketed by cysteine residues as those found in RTS-disintegrins of Crotalidae and Viperidae snake venoms, which act as angiogenesis inhibitors. Endothelial Cell Tube formation assay in vitro and chicken chorioallantoic membrane (CAM) angiogenesis assay in vivo were performed as to investigate the effect of tabRTS on angiogenesis. It was found that tabRTS could significantly inhibit angiogenesis in vitro and in vivo. Anti-alpha(1)beta(1) monoclonal antibody could dose-dependently inhibit the anti-angiogenic activity of tabRTS. This result indicated that tabRTS possibly targets the alpha(1)beta(1) integrin to exert the anti-angiogenic activity as snake venom RTS-/KTS-disintegrins do. The current work revealed the first angiogenesis inhibitor protein containing RTS motif from invertebrates, a possible novel type of RTS-disintegrin. (C) 2009 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The paper deals with a technique to synchronize two crops, fish and makhana (Euryale ferox Salisb) in a pond. In such eco-friendly integration both crops are mutually benefited. Decomposed plant parts of makhana crop form organic matter that releases nutrients in the water to enhance plankton population. Organic detritus not only acts as food for bottom dwelling fishes (mrigal and common carp) but also provides a suitable substratum for the growth of zooplankton, insect larvae, nematodes and gastropods. Fishes contribute to the control of makhana pests. Their faecal matter acts as organic manure for makhana crop. Plankton population fluctuated between 1260 u/l to 4030 u/l in the control pond and 1630 u/l to 4722 u/l in the experimental pond. During the grand growth period of makhana crop (April to July) the dissolved oxygen content fluctuated between 5.02 mg/l to 6.68 mg/l in the covered areas and 6.04 mg/l to 6.92 mg/l in uncovered areas. Makhana leaves acting as blanket barrier over the water surface brought down the D.O. content in the covered areas of the pond. Free CO sub(2) content showed wider fluctuation in the experimental pond (25.2 mg/l to 30.9 mg/l) than in the control pond (25.1 mg/l to 28.6 mg/l). This could be due to decomposition of plant parts of the presiding crop lying as debris at the pond bottom. Autochthonous supply of nutrients enhanced the content of nitrogen, phosphorous and organic carbon in the soil of experimental pond. The experimental pond covering an area of 0.40 ha yielded 852 kg fish and 200 kg pops whereas the control pond covering the same area produced 777 kg fish only. The net profit per ha came out to be Rs.1,04,700 and Rs. 66,200 in integrated and non-integrated system respectively. Owing to crop diversification, the present integrated system was found to be more viable than the non-integrated system in terms of production and net profit.