利用反向遗传操作技术产生ZJI株鹅源新城疫病毒

利用反向遗传操作技术,将ZJI株鹅源新城疫病毒全基因组cNDA克隆(NDV3GM122)和含该毒株NP、P及L基因的3个表达载体(pCI-NP、pCI-P与pCI-L)共转染BSR-T7/5细胞;同时,将NDV3GM122与含新城疫病毒La Sota毒株NP、P及L基因的3个表达载体(pCIneoNP、pCIneoP与pCIneoL)进行共转染。通过间接免疫荧光实验(Indiectimmunofluorescence assay,IFA)以及接种鸡胚后进行血凝(Hemagglutinin,HA)与血凝抑制(Hemagglutinininhibition,HI)试验、RT-PCR扩增和电镜观察,结果均证实全基因组cDNA克隆NDV3GM122与La Sota毒株表达载体共转染组产生了有血凝性的鹅源新城疫病毒,而NDV3GM122与ZJI株表达载体共转染组暂未检测到有血凝性的病毒。ZJI株鹅源新城疫病毒的拯救成功为对该病毒进行功能基因组研究和疫苗的研制等后续工作打下了基础。     

Dam effects on the wintering strategy and habitat use of Greylag Goose (<Emphasis Type="Italic">Anser anser</Emphasis>) in Ichkeul National Park,North Tunisia

The mosaic of habitats in the Ichkeul National Park is frequently changing due to the variations in water conditions that had influenced the wintering strategy of waterbird populations. To this point of view, field work on the wintering strategy of Greylag Geese in the Ichkeul National Park was realized during two consecutive winters (September 2001–March 2002 and September 2002–March 2003). Results showed that in this area, the Greylag Goose was a regular winter visitor, typically from the beginning of October to the end of March, when food resources were totally exhausted in all marshes. Records of diurnal time budget revealed that feeding (43%) and sleeping (20%) dominated all other activities: walking, flying alertness, and preening. The food resource depletion might be the principal responsible for the total population size decreases, the behavioral changes, and the switch of habitats used by the considered species. This situation is a kind of alarm bell to indicate a perturbation of the habitats in the Ichkeul National Park. Therefore, it is essential to use appropriate management strategies to enhance the value of this area for the bio-indicator species, in particular Greylag Goose which is very sensitive to habitat changes.     

Transgenic cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis>) seeds expressing a bean α-amylase inhibitor 1 confer resistance to storage pests,bruchid beetles

Cowpea is one of the important grain legumes. Storage pests, Callosobruchus maculatus and C. chinensis cause severe damage to the cowpea seeds during storage. We employ a highly efficient Agrobacterium-mediated cowpea transformation method for introduction of the bean (Phaseolus vulgaris) α-amylase inhibitor-1 (αAI-1) gene into a commercially important Indian cowpea cultivar, Pusa Komal and generated fertile transgenic plants. The use of constitutive expression of additional vir genes in resident pSB1 vector in Agrobacterium strain LBA4404, thiol compounds during cocultivation and a geneticin based selection system resulted in twofold increase in stable transformation frequency. Expression of αAI-1 gene under bean phytohemagglutinin promoter results in accumulation of αAI-1 in transgenic seeds. The transgenic protein was active as an inhibitor of porcine α-amylase in vitro. Transgenic cowpeas expressing αAI-1 strongly inhibited the development of C. maculatus and C. chinensis in insect bioassays.     

Protective action of salicylic acid against bean yellow mosaic virus infection in Vicia faba leaves

In this study, morphological, ultrastructural and physiological modifications of faba bean (Vicia faba cv Giza 461) leaves in response to bean yellow mosaic virus (BYMV) infection and salicylic acid (SA) treatments were examined. Under BYMV stress, leaves showed symptoms including severe mosaic, mottling, crinkling, size reduction and deformations. Three weeks after virus inoculation, photosynthetic rate, pigment contents and transpiration rate were significantly reduced in response to BYMV infection.

Ultrastructural investigations of BYMV-infected leaves demonstrated that most chloroplasts with increased stromal area became spherical in shape and some lost their envelopes, either partially or totally. The internal structures of chloroplast, grana and thylakoids were dilated. Two kinds of inclusions were detected in BYMV-infected leaves: straight or slightly curved bands sometimes coiled or looped at the end, and electron opaque crystals with varied shapes. BYMV-infected cells showed lower chloroplast number in comparison to the control.

Spraying of SA on faba bean leaves helped to reduce or prevent the harmful effects produced after virus infection. Application of 100 μM SA three days before inoculation restored the metabolism of infected leaves to the levels of healthy controls. SA treatment improved plant health by increasing the photosynthesis rates, pigment contents and levels of other parameters studied similar to control values.

Moreover, SA treatment increased plant resistance against BYMV. This was observed through induction of chloroplast number, reduction in percentage of infected plants, decrease in disease severity and virus concentration of plants treated with SA prior to BYMV inoculation. Cells of SA-treated samples showed well-developed chloroplasts with many starch grains and well-organized cell organelles.

The present results provide an overview of the negative effects on faba bean leaves due to BYMV infection from physiological and subcellular perspectives. Also, a role of SA involved in induction of resistance against BYMV infection in bean plants is discussed.     

鹅IL-2基因在大肠杆菌中的表达及其可溶性单体的分离

将去除信号肽编码序列的鹅IL-2基因克隆到原核表达载体pET-28a (+), 构建了重组表达质粒pET-28a (+)-goIL-2, 转化大肠杆菌BL21(DE3)感受态细胞, 经IPTG诱导, 实现了重组鹅IL-2(rgoIL-2)蛋白在大肠杆菌中的表达。SDS-PAGE和Western-blotting分析显示, 表达蛋白的分子量约为15.0 kD, 能被抗鹅IL-2单克隆抗体特异识别。可溶性分析表明表达蛋白大部分以包涵体形式存在, 部分以可溶形式存在, 非变性电泳可见可溶性蛋白存在单体和多聚体组分。镍柱亲和层析法纯化的rgoIL-2蛋白过滤后, 利用?KTA FPLC(快速蛋白分离纯化系统)进行逐级分离, 非变性电泳可见单一的鹅IL-2可溶性蛋白单体。体外生物学活性分析显示鹅IL-2可溶性蛋白单体能刺激鹅淋巴细胞增殖。这为进一步研究鹅IL-2的生物学功能及其临床应用奠定基础。     

Movements and Survival of Molt Migrant Canada Geese From Southern Michigan

ABSTRACT We studied movements and survival of 250 female giant Canada geese (Branta canadensis maxima) marked during incubation with either satellite-monitored platform transmitting terminals or very high frequency radiotransmitters at 27 capture areas in southern Michigan, USA, in 2000–2003. We destroyed nests of 168 radiomarked females by removing eggs after day 14 of incubation, and we left nests of 82 incubating hens undisturbed after capture and marking. Of females whose nests we experimentally destroyed, 80% subsequently migrated from breeding areas to molt remiges in Canada. Among 82 nests left undisturbed, 37 failed due to natural causes and 51% of those females departed. Migration incidence of birds that nested in urban parks was low (23%) compared with migration incidence of birds that nested in other classes of land use (87%). Departure of females from their breeding areas began during the second and third weeks of May, and most females departed during the last week of May and first week of June. Based on apparent molting locations of 227 marked geese, birds either made long-distance migratory movements >900 km, between latitudes 51° and 64° N, or they remained on breeding areas. Molting locations for 132 migratory geese indicated 4 primary destinations in Canada: Western Ungava Peninsula and offshore islands, Cape Henrietta Maria, Northeast James Bay and offshore islands, and Belcher Islands, Hudson Bay, Canada. Following molt of remiges, Canada geese began to return to their former nesting areas from 20 August through 3 September, with 37% arriving on or before 15 September and 75% arriving on or before 1 October. Migration routes of geese returning to spring breeding areas were relatively indirect compared with direct routes taken to molting sites. Although overall survival from May through November was 0.81 (95% CI: 0.74–0.88), survival of migratory geese marked on breeding sites where birds could be hunted was low (0.60; 95% CI: 0.42–0.75) compared with high survival of birds that remained resident where hunting was restricted (0.93; 95% CI: 0.84–0.97). Nest destruction can induce molt migration, increase hunting mortality of geese returning from molting areas, and reduce human-goose conflicts, but managers also should consider potential impacts of increasing numbers of molt migrants on populations of subarctic nesting Canada geese.     

A simple brassinolide analogue 2α, 3α-dihydroxy-17β-(3-methyl-butyryloxy)-7-oxa-B-homo-5α-androstan-6-one which induces bean second internode splitting

A new synthetic brassinolide analogue, 2,3-dihydroxy-17-(3-methylbutyryloxy)-7-oxa-B-homo-5-androstan-6-one (11), has been shown to exhibit typical brassinolide activity characterised by elongation, swelling, twisting and splitting of the bean second internode. It was prepared from the known lactone 2,3,17-trihydroxy-7-oxa-B-homo-5-androstan-6-one (4) which was transformed to an isopropylidenedioxy derivative. After protection of the 2- and 3-hydroxy groups it yielded the 2,3-isopropylidenedioxy-17-(3-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one (7) on treating with 3-methylbutyryl chloride in pyridine. The analogue with a 2-methylbutyric moiety (10, 2,3-dihydroxy-17-(2-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one) in position 17 stimulated only elongation and swelling of the bean second internode. However, in this bioassay 100 times more 10 or 11 compared to 24-epibrassinolide is required to obtain the same effects. Analogues with -oriented hydroxyl groups at C-2 and C-3 (14,15), a 6-ketone (17,18) or 6-oxa-7-oxo-lactone system (12,13) in ring B lack the typical brassinolide activity. In addition, the active brassinosteroids applied to the second internode stimulated a similar, but 30% lower elongation of the first internode. From data presented here we conclude that the presence of two hydroxy groups in the positions 22 and 23 of the brassinolide side chain, which are considered as a key structural requirement, is not absolutely necessary for a compound to exhibit typical brassinosteroid activity. Nevertheless, these compounds have generally 2–10 times lower activity than that having 22,23-vicinal diol in the side chain.