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In vitro action of ethylmethanesulphonate on banana shoot tips 总被引:2,自引:0,他引:2
Shoot tips excised from two banana (Musa acuminata) clones (SH-3362, a diploid AA, and cultivar ‘Grand Nain’ mutant (GN-60Gy/A), a triploid AAA) were treated with various concentrations of the mutagen ethylmethanesulphonate (EMS). The number of newly initiated adventitious buds decreased with increased concentrations of EMS. Presence of dimethylsulphoxide (DMSO) in combination with EMS affected the growth and development of the shoot tips. Uptake of the labelled mutagen (14C EMS) was greatly influenced by time of incubation and presence of DMSO as a carrier agent. Microautoradiography of histological sections of shoot tips confirmed the accumulation of the labelled mutagen in the shoot apical meristem, leaf primordia and more extensively in the corm, from which new adventitious buds are initiated. 相似文献
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Investigations on the role of the salmon louse,Lepeophtheirus salmonis (Caligidae), as a vector in the transmission of Aeromonas salmonicida subsp. salmonicida
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C W Novak D L Lewis B Collicutt K Verkaik D E Barker 《Journal of fish diseases》2016,39(10):1165-1178
A bacteria–parasite challenge model was used to study the role of sea lice, Lepeophtheirus salmonis (Copepoda), as a vector of Aeromonas salmonicida subsp. salmonicida. Three hypotheses were tested: (i) L. salmonis can acquire A. salmonicida subsp. salmonicida via water bath exposure; (ii) L. salmonis can acquire the bacteria via parasitizing infected Atlantic salmon, Salmo salar; and (iii) L. salmonis can transmit the bacteria to naïve Atlantic salmon via parasitism. Adult L. salmonis exposed to varying A. salmonicida subsp. salmonicida suspensions (101–107 cells mL?1) for 1.0, 3.0 or 6.0 h acquired the bacteria externally (12.5–100%) and internally (10.0–100%), with higher prevalences associated with the highest concentrations and exposures. After exposure to 107 cells mL?1, viable A. salmonicida subsp. salmonicida could be isolated from the external carapace of L. salmonis for 120 h. Lepeophtheirus salmonis also acquired the bacteria externally and internally from parasitizing infected fish. Bacterial transmission was observed only when L. salmonis had acquired the pathogen internally via feeding on ‘donor fish’ and then by parasitizing smaller (<50 g) ‘naive’ fish. Under specific experimental conditions, L. salmonis can transfer A. salmonicida subsp. salmonicida via parasitism; however, its role as a mechanical or biological vector was not defined. 相似文献
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Jana Novotna Vijay Baheti Blanka Tomkova Jiri Militky Jan Novak 《Fibers and Polymers》2018,19(6):1288-1294
The aim of the presented research was to study the influence of surface layer material on improvement of impact, dielectric, EMI shielding and sound absorption properties of sandwich composites. The sandwich composite structure consisted of Kevlar or Carbon woven fabric at the surface layer, recycled high loft nonwoven in the center and a mixture of carbon particles/epoxy matrix as a binder to hold the surface layer and core together. The carbon particles were incorporated in epoxy in order to improve failure mechanism and enhance dielectric properties or electromagnetic shielding of sandwich composites. The biggest improvements on impact properties of sandwich composites were obtained when Kevlar fabric was used as surface layer. However, surface layer of carbon fabric was found to provide better dielectric properties and improve EMI shielding of sandwich composites against Kevlar fabric surface layer. 相似文献
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modENCODE Consortium Roy S Ernst J Kharchenko PV Kheradpour P Negre N Eaton ML Landolin JM Bristow CA Ma L Lin MF Washietl S Arshinoff BI Ay F Meyer PE Robine N Washington NL Di Stefano L Berezikov E Brown CD Candeias R Carlson JW Carr A Jungreis I Marbach D Sealfon R Tolstorukov MY Will S Alekseyenko AA Artieri C Booth BW Brooks AN Dai Q Davis CA Duff MO Feng X Gorchakov AA Gu T Henikoff JG Kapranov P Li R MacAlpine HK Malone J Minoda A Nordman J Okamura K Perry M Powell SK Riddle NC Sakai A 《Science (New York, N.Y.)》2010,330(6012):1787-1797
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L. Krstin S. Novak‐Agbaba D. Rigling M. Krajačić M. Ćurković Perica 《Plant pathology》2008,57(6):1086-1096
In order to improve understanding of its diversity, 338 isolates of Cryphonectria parasitica, the causal agent of chestnut blight, were sampled from 10 chestnut populations throughout chestnut‐growing coastal and continental areas of Croatia. Eighteen vegetative compatibility (VC) types were identified. The VC type EU‐1 was the most widespread, comprising 42·9% of the isolates, followed by EU‐2 (21%) and EU‐12 (14·2%). In respect to the occurrence of the main VC types, the C. parasitica populations in Croatia combined features of both northwestern and southeastern European populations. Perithecia and mating‐type ratios of approximately 1 : 1 were found in all populations, suggesting that sexual reproduction of the fungus is common in Croatia. Natural hypovirulence was also evident in all populations, with incidence of hypovirus‐infected isolates ranging from 12·7% in Istria‐Buje to 66·6% in the continental part of the country. A total of 36 hypovirus‐infected isolates sampled throughout Croatia were analysed in ORF‐A and ORF‐B by RT‐PCR/RFLP analysis. All viral isolates belonged to the Italian subtype of Cryphonectria hypovirus 1 (CHV‐1) and were closely related to the isolates found in other European countries. The RFLP patterns found were also identical or similar to the patterns of three isolates collected in Croatia 22 years ago, suggesting a slow evolution of the hypovirus. 相似文献