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排序方式: 共有195条查询结果,搜索用时 21 毫秒
31.
Laroucau K de Barbeyrac B Vorimore F Clerc M Bertin C Harkinezhad T Verminnen K Obeniche F Capek I Bébéar C Durand B Zanella G Vanrompay D Garin-Bastuji B Sachse K 《Veterinary microbiology》2009,135(1-2):82-89
Five severe cases of psittacosis in individuals associated with duck farms were notified in France between January and March 2006. Diagnostic examination included serology and/or molecular detection by PCR from respiratory samples. As a consequence, we investigated all duck flocks (n=11) that were housed in the three farms where human infections occurred. While serology by complement fixation test was negative for all samples, cloacal and/or tracheal chlamydial excretion was detected by PCR in all three units. Notably, one duck flock was tested strongly positive in 2 of the 3 affected farms, and Chlamydophila (C.) psittaci strains were isolated from cloacal and/or tracheal swab samples from both farms. Human samples and duck isolates exhibited the same PCR-RFLP restriction pattern, which appeared to be an intermediate between genotypes A and B. Analysis of ompA gene sequences and comparison to those of the type strains showed that the isolates could not be strictly assigned to any of the generally accepted genotypes of C. psittaci. Further analysis by MLVA of the PCR-positive human samples revealed two distinct patterns, which were related to previously isolated C. psittaci duck strains. 相似文献
32.
Jones S Prosperi-Porta G Dawe S Blackbourn J Taylor K Lowe G Osborn A 《Folia parasitologica》2004,51(2-3):221-227
An unidentified myxosporean parasite (CKX) is described from the kidney of approximately 80% of spawning coho salmon Oncorhynchus kisutch (Walbaum) in British Columbia, Canada and Washington, United States of America. Morphological features were described using light and electron microscopy. Sequencing of polymerase chain reaction (PCR) amplified 18S ribosomal RNA gene and in situ hybridisation were used to further characterise CKX. The parasite occurred with a focal distribution within tubule epithelial cells, the tubule lumen and the interstitium as primary cells containing from one to at least 16 secondary cells. Luminal stages were degenerate and sporogony was not observed. In situ hybridisation using a digoxygenin-labelled DNA probe confirmed CKX to be the source of DNA used in PCR analyses. CKX 18S rDNA sequences were most similar (97%) to those of Sphaerospora oncorhynchi. Phylogenetic analysis revealed similarities among the 18S rDNA sequences of CKX, S. oncorhynchi and Myxidium lieberkuehni. CKX is hypothesised to be the abortive extrasporogonic development of a Sphaerospora sp. or Myxidium sp. occurring in immune-incompetent spawning and senescent salmon. 相似文献
33.
The color of the seed coats of ‘Dorado’ (Phaseolus vulgaris L.) is garnet brown (dark red kidney bean color) and differs from most other dry bean varieties in the Honduran red bean
market class. A genetic investigation of the color of ‘Dorado’ (same as DOR364) and G19833 (Liborino market class) seed coats
was conducted. Crosses with genetic tester stocks demonstrated that the gene for garnet brown (GB) in ‘Dorado’ was not allelic
with the R gene for dominant red (oxblood) seed coat. An allelism test between the ‘Dorado’ gene for GB seed coat and the rk
drv gene for recessive expression of GB demonstrated allelism. We propose the gene symbol for Rk
r for the ‘Dorado’ GB seed coat color gene. Rk
r expresses partial dominance over Rk, where Rk
r/Rk expresses a paler and highly variable intermediate red color. The interactions of Rk
r, rk
drv, and c
u are discussed. Segregation analysis in the mapping population made up of DOR364 (same as ‘Dorado’) × G19833 recombinant inbred
lines showed that the Rk
r gene mapped to linkage group 1. The new allele at Rk was located at a distance of 17 cM from the RFLP marker Bng130 with a LOD > 3.0. 相似文献
34.
Abstract: Internal conflicts at the local and national levels in several South Pacific countries have revealed the fragility of national unity and the difficulties nations face in governing and managing their own economic development. In Papua New Guinea, the focus of this paper, an uncertain economic future for many rural and urban communities, and rising inequalities in income opportunities and access to resources, have coincided with greater intolerance of migrants at sites of high in‐migration by customary landowners and provincial and local authorities. This paper draws on fieldwork undertaken in the major oil palm growing regions of Papua New Guinea where migrants from densely populated regions of the country have settled on state land alienated from customary landowners. We examine how struggles over land, resource control and development are polarising migrant and landowner identities resulting in increasing tensions and episodic communal violence. A settler identity is emerging based on a narrative of nation building and national development, while an ethno‐regional identity amongst customary landowners is undermining the citizen rights of migrants and challenging the role and authority of the state in land matters. 相似文献
35.
This paper examines the broad range of informal land transactions and arrangements migrants are entering into with customary landowners to gain access to customary land for export cash cropping in the oil palm belt of West New Britain, Papua New Guinea. Whilst these arrangements can provide migrants with relatively secure access to land, there are instances of migrants losing their land rights. Typically, the land tenure arrangements of migrants with more secure access to land are within a framework of property rights for social inclusion whereby customary landowners’ inalienable rights to land are preserved and the ‘outsider’ becomes an ‘insider’ with ongoing use rights to the land. Through socially embedding land transactions in place‐based practices of non‐market exchange, identities of difference are eroded as migrants assume identities as part of their host groups. This adaptability of customary land tenure and its capacity to accommodate large migration in‐flows and expanding commodity production undermines the argument common amongst proponents of land reform that customary tenure is static and inflexible. Before such claims are heeded, there must be more detailed empirical investigations of the diverse range of land tenure regimes operating in areas of the country experiencing high rates of immigration. 相似文献
36.
Benard Yada Agnes Alajo Gorrettie N. Ssemakula Gina Brown-Guedira Milton Anyanga Otema Philip C. Stevenson Robert O. M. Mwanga G. Craig Yencho 《Euphytica》2017,213(6):129
The development of sweetpotato [Ipomoea batatas (L.) Lam] germplasm with resistance to sweetpotato weevil (SPW) requires an understanding of the biochemical and genetic mechanisms of resistance to optimize crop resistance. The African sweetpotato landrace, ‘New Kawogo’, was reported to be moderately resistant to two species of SPW, Cylas puncticollis and Cylas brunneus. Resistance has been associated with the presence of hydroxycinnamic acids esters (HCAs), but the underlying genetic basis remains unknown. To determine the genetic basis of this resistance, a bi-parental sweetpotato population from a cross between the moderately resistant, white-fleshed ‘New Kawogo’ and the highly susceptible, orange-fleshed North American variety ‘Beauregard’ was evaluated for SPW resistance and genotyped with simple sequence repeat (SSR) markers to identify weevil resistance loci. SPW resistance was measured on the basis of field storage root SPW damage severity and total HCA ester concentrations. Moderate broad sense heritability (H2 = 0.49) was observed for weevil resistance in the population. Mean genotype SPW severity scores ranged from 1.0 to 9.0 and 25 progeny exhibited transgressive segregation for SPW resistance. Mean genotype total HCA ester concentrations were significantly different (P < 0.0001). A weak but significant correlation (r = 0.103, P = 0.015) was observed between total HCA ester concentration and SPW severity. A total of five and seven SSR markers were associated with field SPW severity and total HCA ester concentration, respectively. Markers IBS11, IbE5 and IbJ544b showed significant association with both field and HCA-based resistance, representing potential markers for the development of SPW resistant sweetpotato cultivars. 相似文献
37.
Moqrich A Hwang SW Earley TJ Petrus MJ Murray AN Spencer KS Andahazy M Story GM Patapoutian A 《Science (New York, N.Y.)》2005,307(5714):1468-1472
Environmental temperature is thought to be directly sensed by neurons through their projections in the skin. A subset of the mammalian transient receptor potential (TRP) family of ion channels has been implicated in this process. These "thermoTRPs" are activated at distinct temperature thresholds and are typically expressed in sensory neurons. TRPV3 is activated by heat (>33 degrees C) and, unlike most thermoTRPs, is expressed in mouse keratinocytes. We found that TRPV3 null mice have strong deficits in responses to innocuous and noxious heat but not in other sensory modalities; hence, TRPV3 has a specific role in thermosensation. The natural compound camphor, which modulates sensations of warmth in humans, proved to be a specific activator of TRPV3. Camphor activated cultured primary keratinocytes but not sensory neurons, and this activity was abolished in TRPV3 null mice. Therefore, heat-activated receptors in keratinocytes are important for mammalian thermosensation. 相似文献
38.
Gina Cannarozzi Solomon Chanyalew Kebebew Assefa Abate Bekele Regula Blösch Annett Weichert Dominik Klauser Sonia Plaza-Wüthrich Korinna Esfeld Moritz Jöst Abiel Rindisbacher Habte Jifar Victoria Johnson-Chadwick Ermias Abate Wuyan Wang Rizqah Kamies Negussu Husein Worku Kebede Kidist Tolosa Yazachew Genet Kidu Gebremeskel Brikti Ferede Firew Mekbib Federico Martinelli Hans Christian Pedersen Suhail Rafudeen Shimelis Hussein Muluneh Tamiru Naomi Nakayama Mike Robinson Ian Barker Samuel Zeeman Zerihun Tadele 《Euphytica》2018,214(2):31
Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef—an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa’s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released. 相似文献
39.
In intensively irrigated rice cultivation,plant-available silicon(Si)is a crucial nutrient for improving rice productivity.As a source of Si,calcium silicate(CaSiO3)was amended to evaluate the effect of silicate fertilizer on rice production,nitrogen(N)use efficiency,and greenhouse gas(GHG)emission under alternating wetting and drying in a pot experiment using a tropical soil from a paddy field of the International Rice Research Institute(IRRI)in the Philippines.Four levels of CaSiO 相似文献
40.
One hundred and sixty-three wines from La Rioja, Utiel-Requena, and Tarragona were analyzed to determine if there were any differences in the concentrations of six biogenic amines that are found in these three regions. The influence of grape variety, type of vinification, wine pH, malolactic fermentation, and storage in bottle on biogenic amine concentrations was studied. Results show important differences in putrescine and histamine concentrations among regions, varieties of grape, and type of wine; differences were less appreciable for the remaining biogenic amines studied. Low pH prevented biogenic amine formation. Malolactic fermentation and short storage periods in bottle (3-6 months) showed increases in histamine concentration, whereas longer periods of storage led to a general decrease in histamine. Several strains of lactic acid bacteria were isolated in this work, and their ability to form biogenic amines was assayed in synthetic media, grape must, and wine. Grape varieties, different types of winemaking, pH, and lactic acid bacteria may be responsible for the differences observed in the biogenic amine concentrations of the wines analyzed. 相似文献