[Maintaining mechanisms of riparian invertebrate biodiversity: A review]. / æ²³å²¸æ— è„Šæ¤ŽåŠ¨ç‰©å¤šæ ·æ€§ç»´æŒæœºåˆ¶ç ”ç©¶è¿›å±•.

Riparian zones, the critical ecological interfaces between terrestrial and aquatic ecosystems, are species rich habitats. However, riparian zones are seriously threatened by human activities in the world. Riparian invertebrates represent a large proportion of riparian biodiversity, perform various ecological functions, and provide an essential link between aquatic and terrestrial ecosystems. Although many studies have investigated the riparian invertebrate communities, there is lacking a comprehensive summary of maintaining mechanisms underlying riparian invertebrate diversity. This review discussed seven characteristics of riparian zones that might support high riparian invertebrate diversity: flood and drought, nutrient, microhabitat diversity, riparian vegetation, microclimate gradients, food resources and river spatial gradients. Further, we summarized the maintaining mechanisms of riparian invertebrate diversity. Disturbances of periodic flood and drought trigger the reproduction and migration of invertebrates, increase the turnover of invertebrate communities, and create suitable conditions for riparian invertebrates. Adequate nutrients support a high invertebrate diversity by increasing primary productivity of riparian habitats. Elevated microhabitat diversity provides a variety of niche space for specialist riparian invertebrates. Strong microclimate gradients provide complex and diverse habitats and thus facilitate the coexistence of aquatic and terrestrial invertebrates in riparian zones. Cross-ecosystem resource subsidies increase food availability and contribute unique food sources to riparian invertebrates. The differentiation of these factors along river longitudinal and lateral gradients provides conditions for the diversification of riparian invertebrates at a larger scale. Understanding the maintaining mechanisms of riparian invertebrate diversity is important for conservation of riparian biodiversity and integrated management of river ecosystems.

Secretory Expression, Purification, Characterization, and Application of an Aspergillus oryzae Prolyl Aminopeptidase in Bacillus subtilis.

cDNA coding a prolyl aminopeptidase (PAP) was cloned from Aspergillus oryzae and over expressed in Bacillus subtilis with a 6×His tag in N-terminus. The recombinant prolyl aminopeptidase was secreted to extracellular by adding 2 mM CaCl2 and 5% D-sorbitol in TB medium; the enzyme activity in fermented supernatant increased from 7.2 to 41.5 U mL-1. It has been purified 4.3-fold through Ni-chelating affinity chromatography with a recovery of 47.3%. The purified enzyme is stable below 50 °C and within pH 6-11, and with the highest activity at pH 7.5 and 50 °C. Several kinds of salt can activate enzyme activity in a certain concentration and the relative activity was 127.02% even when the concentration of NaCl reached 4.36 M. It cleaved N-terminal Pro residues from many peptides but shown different hydrolysis rates for various Pro-X dipeptides or peptides which are of different lengths. It combined with alkaline protease and leucine aminopeptidase to hydrolyze casein, many free amino acid especially proline and small peptide of hydrolysate increased significantly.

[Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain, Northeast China].

In the present study, an in situ control experiment was carried out to explore the response of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels (6 g N · m(-2)), while decreased it at higher levels (> 12 g N · m(-2)). At genus level, nitrogen addition significantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis. At species level, nitrogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands.

[The analysis of adverse health effects of occupational hazards factors in one solid waste landfill].

OBJECTIVE: To determine occupational hazards in work sites of a large solid waste landfill and analyze their adverse health effects. METHOD: The national standardized detection methods were used to determine dust concentration, harmful gas and physical factors in worksites. Routine physical examination, pulmonary function, hearing tests and nervous system test were performed in workers for 2 consecutive years. Urine lead, cadmium and mercury contents were detected. The comet assay was use to measure DNA damage in peripheral blood lymphocytes among workers. RESULT: The main occupational hazard factors in this solid landfill are dust, harmful gas, high temperature and noise. The oxides, carbon monoxide, and noise and high temperatures in summer at some work sites exceeded the national occupational exposure limits. The prevalence of respiratory inflammation and rate of pulmonary function decrease among front-line workers and on-site technical managers are 21.2% and 11.5%, which are significantly higher than those among administrative staff (7.1% and 0) (P < 0.05). Nervous system abnormalities rate of front-line workers and on-site technical managers was 50.0%, which is significantly higher than that (26.7%) of administrative staff (P < 0.05). Because of long-term exposure to high intensity noice, hearing loss rate of bulldozer drivers was 10.3%. In addition, about 75% of workers with DNA damage in peripheral blood lymphocyte are front-line workers. CONCLUSION: Adverse health effects from occupational hazards were observed among workers in this solid waste landfill.