Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Mais filtros

Base de dados
Intervalo de ano de publicação
Huan Jing Ke Xue ; 40(9): 3973-3981, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854859


Nitrous acid (HONO) is easily photolyzed with the production of·OH, which plays an important role in the formation of regional secondary pollution. In China, research of HONO observation is concentrated mainly in urban areas and is rarely reported in rural areas. In our study, a one-month HONO field observation was conducted at the Station of Rural Environment, Chinese Academy of Sciences (Dongbaituo Village, Wangdu County, Hebei Province) in November 2017 using the long path absorption photo meter (LOPAP). The concentration, variety characteristics, and budget of HONO was studied. During the observation period, HONO exhibited pronounced diurnal variation with low concentrations in the day and high concentration in the evening. The highest concentration at night was about 3.70×10-9, and the lowest concentration at noon was about 0.10×10-9, indicating the presence of a strong source of HONO in rural areas. The CO concentration increased significantly before and after heating, whereas the HONO concentration did not change significantly, indicating that heating combustion contributed less to HONO, Direct emission of motor vehicles at night contributed 23.20% and 31.20% to HONO in polluted and clean weather conditions, respectively, indicating the presence of strong sources of HONO in polluted weather conditions. The average formation rate of HONO at night from homogeneous reaction of·OH and NO could reach 0.40×10-9 h-1, which is 0.67 times higher than that of heterogeneous reaction of NO2 (0.24×10-9 h-1), indicating that the homogeneous reaction of·OH and NO is the main source of HONO at night. HONO has a strong unknown source in the daytime with an intensity reaching 1.37×10-9 h-1, which contributes about 50% to HONO.

J Zhejiang Univ Sci ; 4(3): 336-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12765289


The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT-PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat-P1-1 and Sat-P1-2). Sat-P1-1 contained 335 nucleotides, and Sat-P1-2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat-P1-1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat-P1-2 represents the emergence of a new satellite (necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.

Satélite do Vírus do Mosaico do Pepino/genética , Cucumovirus/química , Cucumovirus/genética , Ervilhas/virologia , Análise de Sequência de RNA , Sequência de Bases , Evolução Biológica , Cucumovirus/classificação , Cucumovirus/crescimento & desenvolvimento , Genes Virais , Dados de Sequência Molecular , Mutação , Conformação de Ácido Nucleico , Ervilhas/genética , Alinhamento de Sequência
Artigo em Inglês | MEDLINE | ID: mdl-12075453


The full-length cDNA of tobacco mosaic virus faba bean isolate (TMV-B) was amplified with RT-PCR in which T7 promoter sequence was added in the 5' terminus of its upstream primer, so that full-length cDNA was put directly under the control of a T7 promoter. The cDNA was cloned into plasmid pT7Blue and linear DNA was got by digesting the recombinant with KpnI or KpnI and PstI. Using these linear DNA and full-length PCR product as templates, respectively, their in vitro transcripts were inoculated to Nicotiana tabacum and Chenopodium amaranticolor. All of the transcripts had infectivity and produced symptoms similar to that of wild TMV. It was found that transcripts of the full-length PCR product had higher infectious efficiency than those of linear DNA.