[Spatiotemporal characteristics of nitrogen and phosphorus in a mountainous urban lake].

Longjing Lake in Chongqing Expo Garden is a typical representative of mountainous urban lake. Based on water quality monitoring of Longjing Lake, spatiotemporal characteristics of nitrogen and phosphorus and their relations were analyzed, combined with natural and human factors considered. The results indicated that annual average concentrations of TN and TP in overall lake were (1.42 ± 0.46) mg · L(-1) and (0.09 ± 0.03) mg · L(-1), nitrogen and phosphorus concentrations fluctuated seasonally which were lower during the flooding season than those during the dry season. Nitrogen and phosphorus concentration in main water area, open water areas and bay areas of Longjing Lake were distributed with temporal and spatial heterogeneity by different regional influencing factors. The seasonal variation of the main water area was basically consistent with overall lake. Two open water areas respectively connected the main water area with the upstream region, bay areas. TN and TP concentrations were gradually reduced along the flow direction. Upstream water quality and surrounding park functional layout impacted nitrogen and phosphorus nutrient concentrations of open water areas. Nutrient concentrations of typical bay areas were higher than those of main water area and open water areas. The mean mass fraction of PN/TN and PP/TP accounted for a large proportion (51.7% and 72.8%) during the flooding season, while NO(3-)-N/TN and SRP/TP accounted for more (42.0% and 59.4%) during the dry season. The mass fraction of ammonia nitrogen and dissolved organic nitrogen in total nitrogen were relatively stable. The annual mean of N/P ratio was 18.429 ± 7.883; the period of nitrogen limitation was 5.3% while was 21.2% for phosphorus limitation.

[Sequence analysis of the phosphoprotein gene of peste des petits ruminants virus of Chinese origin].

The nucleotide sequences of P gene from a field strain of peste des petits ruminants virus (PPRV) ("China/Tib/Gej/07-30") was firstly determined. The P gene is 1,655 nucleotides long with two overlapping open reading frames (ORFs). The first ORF is 1530 nucleotides long and would produce P protein of 509 amino acid residues. The second ORF is 534 nucleotides long and would produce C protein of 177 amino acid residues. The first ORF produces a second mRNA transcript of 897 nucleotides long with an extra G nucleotide at position 751. Translation from this mRNA would produce V protein of 298 amino acid residues. The nucleotide and deduced amino acid sequence were compared with the homologous region of other PPRV isolates. At the amino acid level, the "China/Tib/Gej/07-30" shares homology of 86.10%-97.3%, 84.3%-94.9%, and 82.9%-96.3% for P, C, and V proteins respectively. Several sequence motifs in the P genes were identified on the basis of conservation in the PPRVs and the morbilliviruses.

[Sequence analysis of the matrix protein and fusion protein genes of a field peste des petits ruminants virus strain from Tibet, China].

The nucleotide sequences of M and F genes from a field strain of peste des petits ruminants virus (PPRV) ("China/Tib/Gej/07-30") was firstly determined. The M gene was 1 483 nucleotides in length with a single open reading frame (ORF), encoding a protein of 335 amino acids. The F gene was 2411 nucleotides in length, encoding a protein of 546 amino acids. The resulting nucleotide sequence and the deduced amino acid sequences were compared with the homologous regions of other PPRV isolates. The nucleotide sequences of M and F genes of the "China/Tib/Gej/07-30" was 92.4%-97.7% and 85.5%-96.1% identical to other PPRV isolates, respectively, while a homology of 97.0%-98.2% and 94.3%-98.2% could be observed at the amino acids level respectively. Several sequence motifs in the M and F genes had been identified on the basis of conservation in the PPRVs and the morbilliviruses. The 3' untranslated region of M gene was 443 nucleotides in length with 82.4%-93.5% identical to other PPRV isolates. The 5' untranslated region of F gene was 634 nucleotides in length with 76.2%-91.7% identical to other PPRV isolates.

[Genome sequencing and analysis of a peste des petits ruminants virus isolate, China/Tib/07].

Peste des petits ruminants virus is a member of Morbillivirus Paramyxoviridae. The complete genome of a Peste des petits ruminants virus (PPRV) isolate, China/Tib/07 was sequenced and molecular characteristics was analyzed. The internal sequences of the virus genome were amplified by RT-PCR with primers designed according to the published data in GenBank, while the sequences of the 3' and 5' ends of the genome were determined by RACE. Amplification products were directly sequenced,assembled and analyzed with DNAStar4.0. Results showed that China/Tib/07 genome consisted of 15 948 nucleotides in length, encoding six structural proteins and two non-structural proteins just like other known PPRV genomes. Phylogenetically, the virus genome shared homology of 91.6%-98.1% with Southwest Asian isolates among PPRV strains and the highest homology of 64.3% with rinderpest virus among morbillivirus members.

[Sequence analysis of the nucleocapsid gene and genome promoter region of peste des petits ruminants virus of Chinese origin].

The N gene and genome promoter nucleotide sequence of a Chinese Peste des petits rumiants virus (PPRV) ("China/Tib/Gej/07-30") was firstly determined. The length of N gene was 1689 nucleotides with a single open reading frame (ORF). The nucleotide and deduced amino acid sequence was compared with the homologous region of other PPRV isolates. The nucleotide sequence of the "China/Tib/Gej/07-30" was 91.7%-97.6% identical to other PPRV isolates, while a homology of 94.9%-98.5% could be observed at the amino acids level. The N gene encoded a protein of 525 amino acids. Several sequence motifs were identified on the basis of conservation in the PPRVs and the morbilliviruses. The genome length of promoter region was 107 nucleotides with 91.8%-98.2% identity to other PPRV isolates. Phylogenetic analysis showed that the "China/Tib/Gej/07-30" belonged to the Asian lineage.