Distribution characteristics of microorganisms in sediments of Dagu River and their biological indicator function for evaluating eco-environmental quality of rural river.

The microorganisms in sediments play a crucial role in biogeochemical cycle processes, and numerous studies have shown that microbial community is closely related to environmental factors. However, the usability of sediment microorganisms to evaluate the eco-environment quality of rural rivers has not been adequately explored. This study investigated the distribution characteristics and response of sediment microorganisms to environmental parameters and benthic organisms. Based on the environmental parameters and benthic community indices, the 12 stations were divided into high-polluted group A, moderate-polluted group B and low-polluted group C. Station DG01 and DG02 in group A had the highest level of As and Ni pollution and nutrient concentration, and DG09 in group A had the lowest benthic diversity. Correspondingly, group A had the lowest abundance of Proteobacteria, which has a higher requirement for the environment than Planctomycetes. Group B had the highest sulfide level (97.45 mg/kg), and bacteria (Thiobacillus, Sulfurisoma and Sulfuritalea) with genes involved in sulfur cycling were more enriched in this group. Group C had the lowest level of total nitrogen (243.36 mg/kg), and Rhodanobacteraceae in Xanthomonadales might be a key bioindicator for low nitrogen. In addition, Chlorophyta was found to be more susceptible to heavy metals, and moreover co-occurrence networks showed that microeukaryotes were more sensitive to heavy metal pollution compared to benthic animals and prokaryotes. Therefore, this study suggested that benthic microorganisms especially microeukaryotes could be used as good indicators for evaluating the eco-environmental quality of rural rivers.

Efficiency and ecological safety of herbicide haloxyfop-R-methyl on removal of coastal invasive plant Spartina alterniflora.

Spartina alterniflora is a global invasive plant and has caused considerable damage to coastal wetland ecosystem. This study evaluated the efficiency and ecological safety of herbicide haloxyfop-R-methyl (HPME) in removing S alterniflora in Laizhou Bay. The results showed that the density of regenerated S. alterniflora after 10 months of application of 0.01, 0.02 and 0.03 g/m2 HPME decreased by 86.67 %, 99.16 % and 99.31 %, respectively. Moreover, seed abortion rates were 62.25 %, 92.24 % and 94.82 %, and weight of roots in HPME groups were 56.63 %, 59.99 %, and 40.10 % of those in the control group. After 4 days of application, HPME could not be detected in S. alterniflora and sediments. In addition, HPME did not change sediment physicochemical properties, macrozoobenthos community and microbial community structure during 16 days, but increased the density of native macrozoobenthos after 1 year. Therefore, HPME might be an effective and ecologically safe chemical for the eradication of S. alterniflora.

The complete mitochondrial genome sequence and gene organization of the rainbow runner (Elagatis bipinnulata) (Perciformes: Carangidae).

The complete mitochondrial genome information can play an important role in species identification, phylogeny, evolution research, genetic differentiation, and diversity. Here we determined the complete mitochondrial genome sequence of Elagatis bipinnulata (Perciformes: Carangidae). This circular genome was 16 542 bp in length, and included all 37 typical mitochondrial genes, containing 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and a putative control region. The gene order of E. bipinnulata was identical to that observed in most other vertebrates. Of 37 genes, 28 were encoded by heavy strand, while the other ones were encoded by light strand. According to the phylogenetic analysis based on 13 concatenated protein-coding genes, E. bipinnulata was genetically closer to the species of genus Seriola compared with any other species within Perciformes. This work can provide helpful data for further studies on population genetic diversity and molecular evolution.

The complete mitochondrial genome of Eleotris oxycephala (Perciformes: Eleotridae).

In the present study, we obtained the complete mitochondrial genome sequence of Eleotris oxycephala, which was 16 527 bp in length. This genome consisted of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and a putative control region. Of the 37 genes, 28 were encoded by heavy strand, while nine were encoded by light strand. The overall base composition of this mitogenome was 28.21% for A, 16.81% for G, 24.75% for T, 30.23% for C, respectively, with a slight higher A + T content (52.96%). The phylogenetic analysis based on 13 concatenated protein-coding genes suggested that E. oxycephala as a sister species to Eleotris acanthopoma was clustered in family Eleotridae. This complete mitochondrial genome sequence of E. oxycephala should be helpful for the studies on population genetic structure, molecular evolution and phylogeny of E. oxycephala and related species.

The complete mitochondrial genome sequence and gene organization of Tridentiger trigonocephalus (Gobiidae: Gobionellinae) with phylogenetic consideration.

The complete mitochondrial genome plays an important role in studies of genome-level characteristics and phylogenetic relationships. Here we determined the complete mitogenome sequence of Tridentiger trigonocephalus (Perciformes, Gobiidae), and discovered its phylogenetic relationship. This circular genome was 16 662 bp in length, and consisted of 37 typical genes, including 13 protein-coding genes, 22 tRNA genes, and two rRNA genes. The gene order of T. trigonocephalus mitochondrial genome was identical to those observed in most other vertebrates. Of 37 genes, 28 were encoded by heavy strand, while the others were encoded by light strand. The phylogenetic tree constructed by 13 concatenated protein-coding genes showed that T. trigonocephalus was closest to T. bifasciatus, and then to T. barbatus among the 20 species within suborder Gobioidei. This work should facilitate the studies on population genetic diversity, and molecular evolution in Gobioidei fishes.

The complete mitochondrial genome and gene organization of Cubiceps squamiceps (Perciformes: nomeidae) with phylogenetic consideration.

In this study, we reported the complete mitochondrial DNA sequence of Cubiceps squamiceps, and its phylogenetic relationship. The full length of this mitogenome was 16 510 bp, including 22 transfer RNA genes, two ribosomal RNA genes, 13 protein-coding genes, and a putative control region. The location of genes in mitochondrial genome was similar to other fish species within family Nomeidae. Twenty-eight genes were located on the heavy strand, while nine genes were located on the light strand. The nucleotide composition of this mitogenome was 27.5% for A, 28.5% for C, 17.5% for G, and 26.5% for T. From the NJ phylogenetic tree, we can find that C. squamiceps was genetically closest to C. pauciradiatus among 20 species within suborder Stromateoidei. This study could lay the basis for the future studies in population genetic diversity, taxonomic status, molecular systematics, and conservation genetics in C. squamiceps.

The complete mitochondrial genome sequence and gene organization of Amblychaeturichthys hexanema (Gobiidae: Amblychaeturichthys) with phylogenetic consideration.

We sequenced and characterized the complete mitochondrial genome of Amblychaeturichthys hexanema and uncovered its molecular phylogenetic relationship. This genome was 18 642 bp in size, and contained 37 classic genes, including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The gene organization and nucleotide composition were the same with those found in most other Gobiidae fishes. In contrast, gene NADH 6 was obviously larger than the same gene identified from other Gobiidae species. Two big repeat regions were detected on both sides of D-loop region. The A + T content (71.2%) of D-loop region was higher than any other region in this genome. Among 37 genes, 28 were encoded by the heavy strand, while nine were encoded by the light strand. The total nucleotide composition of this genome was 28.6% for A, 15.8% for G, 27.2% for C, and 28.3% for T, with a high A + T content of 56.9%. Phylogeny analysis of 22 fish species within Gobioidei showed that A. hexanema and Chaeturichthys stigmatias first formed a single cluster, then they together with other 17 species grouped a big branch. This work should be helpful for the studies on population genetic diversity and molecular evolution of Gobiidae fish species.

Isolation and characterization of the complete mitochondrial genome of Taenioides anguillaris (Gobiidae: Amblyopinae) with phylogenetic consideration.

Here we first isolated and characterized the complete mitochondrial genome DNA of Taenioides anguillaris. It was 16 974 bp in length, and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and a putative control region. The structure and the gene arrangement of this genome were identical to those isolated from other Gobiidae fishes. Twenty-eight genes were encoded by heavy strand, while nine genes were encoded by light strand. The total nucleotide composition of this genome was 28.7% for A, 15.6% for G, 28.6% for C, and 27.1% for T, with a high A + T content of 55.8%. From the neighbor-joining (NJ) phylogenetic tree, we can find that T. anguillaris was genetically closest to species Odontamblyopus rubicundus among 20 species within suborder Gobioidei. This work should be helpful for the studies on population genetic diversity and molecular evolution in T. anguillaris and related fish species.

Two transcripts of HMG-CoA reductase related with developmental regulation from Scylla paramamosain: Evidences from cDNA cloning and expression analysis.

3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductases (HMGRs), which catalyze the conversion of HMG-CoA to mevalonate, may have an important role in the synthesis of methyl farnesoate (MF). In this study, we obtained two HMGR cDNA sequences termed Sp-HMGR1 (membrane-bound form) and Sp-HMGR2 (soluble form), which encode 967 and 654 amino acids, respectively. The two cDNAs possess entirely identical sequences except that Sp-HMGR1 is 1,382 bp, which encodes a sterol-sensed domain (SSD; a membrane-bound domain) and was first found in crustacean HMGR, larger than Sp-HMGR2. Thus, it was deduced that these cDNAs might be derived from a single genomic DNA sequence. Sp-HMGRs have the typical features of the HMGR class of proteins. However, residue 844 in Sp-HMGR1, which is usually occupied by a Ser residue in other species, has an unusual Ala substitution. This Ser is thought to be involved in enzyme activity regulation by reversible phosphorylation. A putative "PEST" sequence that, until now, has only been found in crustacean species was also identified in the C-terminus of both transcripts, and a sterol-sensing domain, which was first found in crustacean species, was identified in Sp-HMGR1; these findings suggest that Sp-HMGR might function in some special regulatory mechanism. Furthermore, the quantitative real-time polymerase chain reaction results showed that the two transcripts have different expression patterns; Sp-HMGR2 was mainly expressed in the mandibular organ (MO) of adult crabs, whereas Sp-HMGR1 was mainly expressed in other tissues and fertilized eggs up until the fourth juvenile crab stage. The fluctuating gene expression seemed to suggest a relationship between Sp-HMGRs and the development of the crab, especially during the larval stage. Besides, the fluctuation of Sp-HMGR1 in ovary, brain, and thoracic ganglia during the ovary development seemed to have some correlation with the nutrition accumulation of ovaries, whether the SSD domain evolved in this process deserve further investigation. Moreover, it remains unclear whether the significant variation in ovary, brain, and thoracic ganglia during ovary development suggests that other tissues in addition to the MO could synthesize MF.

[Determination of uric acid by chemiluminescence].

A novel chemiluminescence method for the determination of uric acid based on its inhibitory effect on the catalysis of Co2+ for the oxidation of luminol by H2O2 is described. The proposed method is simple, very sensitive and inexpensive. The decrease of cheniluminescence intensity is linearly correlated with uric acid concentration. The calibration graph is linear over the range of 1.0 x 10(-10) - 7.0 x 10(-6) mol x L(-1) and the detection limit is 1.1 x 10(-11) mol x L(-1). The relative standard deviation (RSD) for 5.0 x 10(-8) is 1.9% (n=4). The method has been successfully applied to the determination of uric acid in human urine and serum samples.

[Determination of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside in the traditional Chinese preparation by high performance liquid chromatography with chemiluminescence detection].

Based on the chemiluminescence reaction of KMnO4-HNO3-2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside sensitized by HCHO, an analytical method for 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside by RP-HPLC with chemiluminescence detector was developed. The chromatographic conditions were optimized. AN ODS hypersil column(25 mm x 4.0 mm, 125 x 4.0 mm i.d. 5 microm) was used with acetonitrile--0.3% H3PO4 [25:75, (phi)] as mobile phase, and the flow rate was 0.8 mL x min(-1) at the column temperature of 40 degrees C. The linear range of calibration curve was from 15.75 to 136.5 microg x mL(-1), the detection limit was 11.83 microg x mL(-1) with a concentration of 21 microg x mL(-1) of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside, and the recovery was 102%-108%. The relative standard deviation was 3.45% (Cs = 21.0 microg x mL(-1), n = 3). The method has been applied to the determination of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside in a few Chinese medicines, and the results were satisfactory. The method was simple, rapid and highly selective.

[Determination of Levofloxacin by chemiluminescence method].

A novel chemiluminescence method for the determination of Levofloxacin is based on its enhancement effect on thereaction of luminol with H2O2. The calibration graph is linear over the range of 5.53 x 10(-11)-2.21 x 10(-8) mol x L(-1) and the detection limit is 1.38 x 10(-11) mol x L(-1). The relative standard deviation (RSD) is 2.56% (n = 9). The method has been successfully applied to the determination of Levofloxacin in capsule samples.