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1.
Seed transmission of turnip yellow mosaic virus in winter turnip and winter oilseed rapes 总被引:1,自引:0,他引:1
This is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape (Brassica napus var. silvestris) cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities. The proportion of infected seeds produced by artificially infected plants of winter oilseed rape (Brassica napus ssp. oleifera) and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus-infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL-507 0.2%, SL-509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seedlings. 相似文献
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TERESA MARYAKA HALSZKA OSMÓLSKA 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1979,12(3):265-273
Supraorbital bones in Saurolophus angustirostris are described, and their presence in all hadrosaurs is suggested. Frontal-nasal and premaxillar-nasal fontanellae are distinguished in hadrosaurs; their presence is explained as connected with growth and considered to he responsible for the variability of crest structures. New data indicating the presence of a cartilaginous diverticulum nasi within the circumnarial depression in Saurobphus ongustirostris are presented. A physiological (respiratory and/or thermoregulatory) function of the nasal diverticulum is proposed. 相似文献
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The paper presents multiplex panels of polymorphic microsatellites for two closely related cryptic species Pipistrellus pipistrellus and Pipistrellus pygmaeus. We tested the cross‐species amplification of 34 microsatellite loci, originally developed for five vespertilionid bat species. Ten and nine polymorphic loci in P. pipistrellus (mean number of alleles per locus = 10.5) and P. pygmaeus (8.1), respectively, in three multiplex polymerase chain reactions per species were amplified. All loci can be analysed in a single fragment analysis and can be used as markers to the study of evolution and the ecology of structured populations of socially living bats. 相似文献
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J?Craig CohenEmail author Lennart?KA?Lundblad Jason?HT?Bates Michael?Levitzky Janet?E?Larson 《BMC genetics》2004,5(1):21
Background
Cystic Fibrosis is a pleiotropic disease in humans with primary morbidity and mortality associated with a lung disease phenotype. However, knockout in the mouse of cftr, the gene whose mutant alleles are responsible for cystic fibrosis, has previously failed to produce a readily, quantifiable lung phenotype. 相似文献8.
Transitions from the anovulatory to the ovulatory season (n=20) and ovulatory to anovulatory season (n=11), were monitored daily by transrectal ultrasonography in wapiti. In 17 of 20 observations, the first interovulatory interval (IOI) was short (9.1+/-0.3 days; mean+/-S.E.M.) compared with later in the ovulatory season (21.3+/-0.1) and the last IOI (21.2+/-0.6 days). With one exception, the short IOI were composed of only one wave of follicular development. Subsequent IOI were composed of two or three waves. Maximum diameters of the first two ovulatory follicles were similar (11.3+/-0.4 mm versus 11.3+/-0.2 mm), but both were larger (P<0.05) than the last two ovulatory follicles of the ovulatory season (10.3+/-0.3 and 10.1+/-0.4 mm). Multiple ovulations occurred in three hinds at the first ovulation of the season and in one hind at the second ovulation, but were not at any other time. Day-to-day profiles of CL diameter and plasma progesterone concentration were smaller (P<0.05) for short versus long IOI. Maximum diameter (12.8+/-0.6 mm versus 12.5+/-0.6 mm) and the diameter profile of the last CL of the season were not different from that of the previous CL. In summary, transition to regular ovulation occurred over a 3-week interval and was preceded by one short IOI (9 days). Multiple ovulations were detected only at the onset of the ovulatory season. The characteristics of the last IOI of the ovulatory season were similar to those reported during the rut. The wave pattern of follicle development was maintained throughout both fall and winter transition periods and follicular wave emergence was preceded by a surge in serum FSH concentrations. Transition to anovulation occurred over a 3-month interval and was marked by a failure of the dominant follicle to ovulate after a typical luteal phase. 相似文献
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JAMES A. NICHOLLS SONJA PREUSS ALEXANDER HAYWARD GEORGE MELIKA GYÖRGY CSÓKA JOSÉ‐LUIS NIEVES‐ALDREY RICHARD R. ASKEW MAJID TAVAKOLI KARSTEN SCHÖNROGGE GRAHAM N. STONE 《Molecular ecology》2010,19(3):592-609
Little is known about the evolutionary history of most complex multi‐trophic insect communities. Widespread species from different trophic levels might evolve in parallel, showing similar spatial patterns and either congruent temporal patterns (Contemporary Host‐tracking) or later divergence in higher trophic levels (Delayed Host‐tracking). Alternatively, host shifts by natural enemies among communities centred on different host resources could disrupt any common community phylogeographic pattern. We examined these alternative models using two Megastigmus parasitoid morphospecies associated with oak cynipid galls sampled throughout their Western Palaearctic distributions. Based on existing host cynipid data, a parallel evolution model predicts that eastern regions of the Western Palaearctic should contain ancestral populations with range expansions across Europe about 1.6 million years ago and deeper species‐level divergence at both 8–9 and 4–5 million years ago. Sequence data from mitochondrial cytochrome b and multiple nuclear genes showed similar phylogenetic patterns and revealed cryptic genetic species within both morphospecies, indicating greater diversity in these communities than previously thought. Phylogeographic divergence was apparent in most cryptic species between relatively stable, diverse, putatively ancestral populations in Asia Minor and the Middle East, and genetically depauperate, rapidly expanding populations in Europe, paralleling patterns in host gallwasp species. Mitochondrial and nuclear data also suggested that Europe may have been colonized multiple times from eastern source populations since the late Miocene. Temporal patterns of lineage divergence were congruent within and across trophic levels, supporting the Contemporary Host‐tracking Hypothesis for community evolution. 相似文献