鹅源新城疫病毒血凝素-神经氨酸酶基因的序列分析

Six isolates of Newcastle disease virus were derived from south and east China regions during the disease outbreaks called "avian paramyxovirus infection of geese" or "geese paramyxovirus infection",and partial sequence analysis of hemagglutinin-neuraminidase(HN) gene was carried out to identify the genetic characteristics of these goose isolatesA 1905 nucleotide portion of HN gene of each of the 6 isolates was sequenced,the results revealed that the coding region of their HN genes are all 1716 nucleotides in length,which can encode 571 amino acid residues aloneThe coding region is followed by a noncoding sequence of 189 nucleotidesThough they diverged only 08%-37% from each other in the nucleotide sequences of coding region,they differed by 175%-179% to F48E8, a standard challenge strain of chicken originCysteine residues are well conserved throughout the amino acid sequences,while the number of the potential glycosylation sites varys from 4 to 6Residue positions Thr 48,His 54,Ser 77,Ala 266,His 340 and Lys 384 are also highly conserved in the 6 goose isolatesThe corresponding residues in other NDV strains are commonly Met 48,Ser 54,Asn 77,Ile 266,Tyr 340 and Glu 384However,the sequences of receptor-binding related regions show no difference to the 14 reference strains from domestic or abroad     

Heterogeneous inbred populations are useful as sources of near-isogenic lines for RAPD marker localization

The development and use of RAPD markers for applications in crop improvement has recently generated considerable interest within the plant breeding community. One potential application of RAPDs is their use for tagging simply-inherited (monogenic) pest-resistance genes and enabling more efficient identification and selection of genotypes carrying specific combinations of resistance genes. In this report, we propose and describe the use of heterogeneous inbred populations as sources of near-isogenic lines (NILs) for targeting RAPD markers linked to major pest resistance genes. The development of these NILs for RAPD marker analyses involved a sequence of line and mass selection during successive generations of inbreeding. DNA bulks derived from the NILs were used to identify a RAPD marker (designated OK14₆₂₀, generated by 5-CCCGCTACAC-3 decamer) that was tightly linked (2.23±1.33 centiMorgans) to an important rust [Uromyces appendiculatus (Pers.) Unger var. appendiculatus] resistance gene (Ur-3) in common bean (Phaseolus vulgaris L.). The efficiency of this approach was demonstrated by a low rate of false-positives identified, the tightness of the linkage identified, and the ability to detect polymorphism between genomic regions that are representative of the same gene pool of common bean. This method of deriving NILs should find application by researchers interested in utilizing marker-assisted selection for one or more major pest resistance genes. The identification of OK14₆₂₀ should help to facilitate continued use of the Ur-3 resistance source and will now enable marker-assisted pyramiding of three different bean rust resistance sources (two previously tagged) to provide effective and stable resistance to this important pathogen.Research supported in part by the grant DAN 1310-G-SS-6008-00 from the USAID Bean/Cowpea Collaborative Research Support Program, the Michigan Agricultural Experiment Station, and the USDA-ARS. Mention of a trademark or a proprietary product does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other products that may also be suitable     

Towards an integrated linkage map of common bean 2. Development of an RFLP-based linkage map

Summary A restriction fragment length polymorphism (RFLP)-based linkage map for common bean (Phaseolus vulgaris L.) covering 827 centiMorgans (cM) was developed based on a F₂ mapping population derived from a cross between BAT93 and Jalo EEP558. The parental genotypes were chosen because they exhibited differences in evolutionary origin, allozymes, phaseolin type, and for several agronomic traits. The segregation of 152 markers was analyzed, including 115 RFLP loci, 7 isozyme loci, 8 random amplified polymorphic DNA (RAPD) marker loci, and 19 loci corresponding to 15 clones of known genes, 1 virus resistance gene, 1 flower color gene, and 1 seed color pattern gene. Using MAPMAKER and LINKAGE-1, we were able to assign 143 markers to 15 linkage groups, whereas 9 markers remained unassigned. The average interval between markers was 6.5 cM; only one interval was larger than 30 cM. A small fraction (9%) of the markers deviated significantly from the expected Mendelian ratios (121 or 31) and mapped into four clusters. Probes of known genes belonged to three categories: seed proteins, pathogen response genes, and Rhizobium response genes. Within each category, sequences homologous to the various probes were unlinked. The I gene for bean common mosaic virus resistance is the first disease resistance gene to be located on the common bean genetic linkage map.     

Production of the chlorosis inducing toxin in liquid cultures ofPseudomonas phaseolicola (Burkh.) Dowson

Amino acids affected amount and time course of the toxin production on complex as well as on chemically defined media. With glutamic acid the toxin content was high in the early growth stage but decreased later on, while the reverse was true with cysteine as single amino acid.Toxin production was highest at temperatures below 20°C. Generally, the toxin production started during the rapid growth phase and reached its maximum shortly after growth ceased. Chloramphenicolinhibited bacteria did not produce much toxin. Bacterial cells contained relatively low amounts of the toxin. Conditions for toxin production in large quantities are described. The feasibility to produce tritiummarked toxin was studied.Comparison of different strains showed that avirulent or weakly virulent halo-less strains do not produce detectable amounts of toxin. However, there was no correlation of the toxin production to the grouping of the bacterial strains in race 1 or the more virulent race 2.     

Canada geese (Branta canadensis) nesting on elevated structures in urban Indiana,USA

The Canada goose (Branta canadensis) population has radically changed over the past 60 years—from once being extirpated in the state of Indiana to the current level of approximately 113,000. High urban densities have resulted in persistent human–wildlife conflicts and novel interactions between geese and their physical environment. Canada geese typically choose nest sites that are on the ground or slightly elevated sites such as muskrat lodge, but we report observations of Canada geese nesting on rooftops 2.6–12.2 m above ground level in central Indiana. These observations suggest that alternative, unpredicted nesting sites are being chosen over more traditional sites, in a likely attempt to reduce risks of disturbance and predation. This atypical nest‐site selection may pose new management challenges, but further research is needed.     

Serial agonistic attacks by greylag goose families, Anser anser, against the same opponent

It is known from primates that alliance partners may support each other's interests in competition with others, for example, through repeated agonistic attacks against a particular individual. We examined serial aggressive interactions between greylag goose families and other flock members. We found that repeated attacks towards the same individual were common and that up to five serial attacks by family members followed an initial attack. Family size did not affect the frequency of such serial attacks. Juvenile geese evidently benefited most from active social support through serial attacks. About 60% of the juveniles' lost primary interactions were subsequently reversed by another family member. This may be one of the reasons why juveniles rank higher in the social hierarchy than would be expected from their age and size alone. Losses in serial attacks predominantly occurred against other, presumably higher-ranking, family geese and ganders. We propose three major functions/consequences of serial attacks. Analogous to primates, serial attacks in greylag geese may serve to reinforce a losing experience of an opponent defeated in a preceding attack. On the side of the winning family, serial attacks may reinforce the experience of winning. Both winning and losing experiences are linked with physiological consequences in higher vertebrates, affecting the future social performance of winners or losers. Finally, serial attacks may signal the agonistic potential of a family to other flock members. This is supported by heart rate data, which indicate that greylags are competent to interpret third-party relationships.     

Relationship between xylem ion concentration and bean growth responses to short-term salinisation in spring and summer

Bean plants, Phaseolus vulgaris L. cv. Contender, were grown in the spring and summer seasons to study the relationship between xylem Na+/Cl-, transpiration rate, and salt tolerance. Eight-day-old seedlings were transplanted to 50% modified Hoagland solution with 1 mM NaCl. Four days after transfer, one of two treatments was applied: a control of 1 mM NaCl or a treatment of 25 mM NaCl every two days to reach a final treatment concentration of 75 mM NaCl. Plants were sampled on the fourth day after the final salt concentration was reached, eight days after the salinisation treatment began. Relative growth rate was 2.6-fold greater in summer than in spring. However, while no differences were found between treatments in spring, summer salt-treated plants had growth rates that were 31% lower than those of controls. In summer, CO2 assimilation, stomatal conductance, and transpiration rate of salinised plants declined with respect to controls. Leaf Na+ and trifoliolate leaf Cl- were higher in salt-treated plants in summer, although root Na+ was significantly higher in spring. Moreover, in summer salinity inhibited Ca2+ and K+ uptake and changed its distribution. Summer salt-treated plants had an average of 17-fold higher xylem Na+ during the daily cycle, while xylem Cl-, only in the afternoon, showed higher values (1.5-fold) compared to spring-grown plants. Our results suggest that the faster growth response to salt in summer-grown bean was at least partly due to an increase in xylem Na+ independent of the transpiration rate and possibly related to an increase in xylem Na+ influx or/and Na+ recirculation.     

Effect of aggregation on the reproductive rate of populations

The effect of spatial distribution on the reproductive rate of a population was examined by applying an approximate equation to several data based on the entomological literature. This study suggests that aggregation generally reduces the equilibrium level of the population density if the population density is not very high.     

The impact of nutrient loading from Canada Geese (<Emphasis Type="Italic">Branta canadensis</Emphasis>) on water quality,a mesocosm approach

A mesocosm experiment determined the impact of Canada Goose (Branta canadensis) feces on water chemistry. After 30 days of fecal additions (treatments of 1.209, 2.419 g, and 12.090 g every 3 d to 0.811 m³ size mescosms), no significant changes in water column total phosphorus, nitrate, N:P ratios, total Kjeldahl nitrogen, chlorophyll-a, or phycocyanin were observed among treatment groups. Soluble reactive phosphorus showed a marginally significant increase in the high treatment group. A settling experiment suggested that goose feces and associated nutrients settled quickly to the sediment. Since fecal material settles quickly to the sediment, the impact of additional fecal material would not become evident in a lake until a wind event mixes the sediment into the water column or through alteration of the productivity or community structure of the benthos. Handling editor: K. Martens     

Lethal and sublethal effects of synthetic insecticides on the locomotory and feeding behavior of Riptortus pedestris (Hemiptera: Alydidae) under laboratory conditions

The bean bug, Riptortus pedestris (Hemiptera: Alydidae) is a polyphagous insect pest and has a wide range of hosts including leguminous plants and tree fruits. Currently, the management of R. pedestris mainly relies on the use of insecticides, and most studies have focused on the lethal effects of insecticides. However, insecticides can not only kill insects directly, but can also affect behavioral changes of survivors when exposed to sub-lethal doses. In this study, we investigated locomotory behaviors (vertical movement, horizontal movement, and flight ability) and feeding behaviors (frequency of insects approaching dried soybean seeds and number of stylet sheaths left on the dried soybean seeds by insects) of surviving R. pedestris pre-exposed to five insecticide residues for 4 h. None of the three insecticides (bifenthrin, etofenprox, and acetamiprid) tested had significant effects on the locomotory behaviors of R. pedestris adults compared to the water-treated control group. Fenitrothion- and dinotefuran-treated groups showed a significant decrease in the vertical movement compared to the water-treated control, but the insects recovered mobility 24 h after the initial exposure. The frequency of R. pedestris approaching to dried soybean seeds was affected by four insecticides (fenitrothion, etofenprox, bifenthrin, and dinotefuran), but the actual feeding activity of R. pedestris determined by the stylet sheaths remaining on the dried soybean seed was only affected by fenitrothion treatment. Given the relatively low toxic effects of five insecticides tested, a better understanding of the impact of insecticides on the behavior of target species is needed for a more robust pest control strategy and a more effective use of insecticides in IPM programs.