专一性脱硫菌的鉴定及高DBT降解力菌株的选育

从大庆油田土壤中分离得到1株可降解二苯并噻吩(DBT)的脱硫微生物HDBS-1,对该微生物的种属地位进行了鉴定并通过诱变手段提高了该菌株的脱硫能力。经过形态观察、生理生化特征分析及16S rDNA序列测定发现该微生物为坂崎肠杆菌(Enterobacter sakazakii),该菌种可以按特异性脱硫途径(简称4S途径)将DBT转化为2-羟基联苯(2-HBP)。利用紫外线(UV)、硫酸二乙酯(DES)和UV+DES对该菌株复合诱变后,得到菌株HDBS-4,其降解DBT生成2-HBP的能力得到了极大的提高,发酵液中2-HBP生成含量(2.574 mg/L)较原始菌株(0.434 mg/L)提高了5.93倍。     

Effects of silver carp (Hypophthalmichthys molitrix) and nutrients on the plankton community of a deep,tropical reservoir: an enclosure experiment

1. An in situ enclosure experiment was conducted in a deep reservoir of southern China to examine (i) the effects of a low biomass (4 g wet weight m^?3) of silver carp (Hypophthalmichthys molitrix) and nutrients on the plankton community and (ii) the response of Daphnia to eutrophication. 2. In the absence of fish, Daphnia galeata dominated the zooplankton community, whereas calanoids were dominant in the fish treatments, followed by D. galeata. Silver carp stocking significantly reduced total zooplankton biomass, and that of D. galeata and Leptodorarichardi, but markedly increased the biomass of smaller cladocerans, copepod nauplii and rotifers. In contrast, nutrient enrichment had no significant effect on the plankton community except for cyclopoids. 3. Chlorophyta, Cryptophyta and Bacillariophyta were dominant phytoplankton groups during the experiment. Chlorophyta with high growth rates (mainly Chlorella vulgaris in the fish enclosures and Ankyra sp. in the fishless enclosures) eventually dominated the phytoplankton community. Total phytoplankton biomass and the biomass of edible phytoplankton [greatest axial linear dimension (GALD) < 30 μm], Chlorophyta, Cryptophyta, Bacillariophyta and Cyanobacteria showed positive responses to fish stocking, while inedible phytoplankton (GALD ≥ 30 μm) was significantly reduced in the fish enclosures. However, there was no significant effect on the plankton community from the interaction of fish and nutrients. 4. Overall, the impact of fish on the plankton community was much greater than that of nutrients. High total phosphorus concentrations in the control treatment and relatively low temperatures may reduce the importance of nutrient enrichment. These results suggest it is not appropriate to use a low biomass of silver carp to control phytoplankton biomass in warmer, eutrophic fresh waters containing large herbivorous cladocerans.     

Hygropreference behaviour and humidity detection in the yellow‐spined bamboo locust,Ceracris kiangsu

Water is a critical resource for all terrestrial insects. The yellow‐spined bamboo locust Ceracris kiangsu Tsai (Oedipodidae: Orthoptera), matures, copulates and reproduces in the summer and adults are observed mud‐puddling in human urine‐contaminated materials on hot days. Besides obtaining NaCl and NH₄HCO₃, the locust may also compensate for water deficiency. In a dual‐choice test in the laboratory, adults prefer to remain on wet rather than dry filter paper at high temperature (36 °C). The females are more likely to move towards and stay on wet filter paper than males. The adults chew wet filter paper in the laboratory at higher temperature and the females consume more than the males. Moreover, foam plastic containing an aqueous solution of an insecticide, bisultap, results in greater mortality in females than a dry formulation, both in the laboratory and the field. The water content of the frass from males is significantly lower than that from females and may partially explain the stronger hygropreference behaviour in females. Other possible reasons for sexually different hygropreference are also discussed. The removal of the adult antennae substantially reduces discrimination between wet and dry filter paper and mortality resulting from wet bisultap formulations in the laboratory. Hence, antennae mediate, at least partially, hygropreference behaviour.     

Effects of photoperiod and temperature on diapause induction and termination in the swallowtail,Sericinus montelus

Abstract Sericinus montelus overwinters as diapausing pupae. In the present study, the effects of photoperiod and temperature on diapause induction and termination of diapause are investigated. The results obtained demonstrate that high temperature can reverse the effect of short day‐lengths on diapause induction. Under an LD 12 : 12 h photoperiod, all pupae enter diapause at 15, 20 and 25 °C, whereas all pupae develop without diapause at 35 °C. No pupae enter diapause under an LD 14 : 10 h photoperiod when the temperature is above 20 °C. Photoperiodic response curves obtained at 25 and 30 °C indicate that S. montelus is a long‐day species and the critical day‐length is approximately 13 h at 25 °C. At 25 °C, the duration of diapause is shortest when the diapausing pupae are maintained under an LD 16 : 8 h photoperiod and increases under LD 14 : 10 h and LD 12 : 12 h photoperiods. Under an LD 16 : 8 h photoperiod, the duration of diapause is shortest when the diapausing pupae are maintained at 25 °C, followed by 20 and 30 °C, and then at 15 °C. These results suggest that a moderate temperature favours diapause development under a diapause‐averting photoperiod in this species. The duration of diapause induced by an LD 12 : 12 h photoperiod is significantly longer at 25 °C than those at 15, 20 and 30 °C, and is shortest at 15 °C. At 25 °C, the duration of diapause induced by LD 6 : 18, LD 12 : 12 and LD 13 : 11 h photoperiods is similar and longer than 90 days. Thus, the diapause‐inducing conditions may affect diapause intensity and a photoperiod close to the critical day‐length has significant influence on diapause intensity in S. montelus.     

Twelve polymorphic microsatellite loci for the South China tiger Panthera tigris amoyensis

Twelve microsatellite loci were found from genomic DNA‐enriched libraries of the South China tiger (Panthera tigris amoyensis). The number of observed alleles for each locus in 53 individuals ranged from five to 14; the expected and observed heterozygosity was 0.480 to 0.883 and 0.333 to 0.956, respectively; and the mean polymorphic information content (PIC) was 0.729. These markers would be considered a useful tool for the study of genetic variation in South China tiger in the future.     

Spirotontonia taiwanica n. sp. (Ciliophora: Oligotrichida) from the Coastal Waters of Northeastern Taiwan: Morphology and Nuclear Small Subunit rDNA Sequence

ABSTRACT. The marine oligotrichous ciliate Spirotontonia taiwanica n. sp. isolated from the coastal waters of northeastern Taiwan is reported, using live observation, protargol preparations and molecular data. The new species differs from the most similar, known congener Spirotontonia turbinata in the following features: (1) lower number of buccal membranelles (11–13 vs. 13–17); (2) higher number of whorls of girdle kinety (2.5 vs. 1.5); (3) lower number of macronuclear nodules (20–31 vs. 28–40); (4) larger cell size (80–104 × 40–72 vs. 44–75 × 29–56 μm); (5) larger anterior cell end to buccal vertex (50 vs. 33 μm); (6) larger ratio of cell length to cell width (1.74 vs. 1.38); (7) the different beginning of the girdle kinety (posterior to the buccal vertex vs. left of the buccal zone portion); and (8) the disappearance of the L‐shaped argyrophilic structures in the last half whorl and occasionally the first 1–10 dikinetids (i.e. yes vs. no). The molecular data also reveal two distinct species, deviating by 2% or 33% base pairs.     

Parastrombidinopsis minima n. sp. (Ciliophora: Oligotrichia) from the Coastal Waters of Northeastern Taiwan: Morphology and Small Subunit Ribosomal DNA Sequence

ABSTRACT. Parastrombidinopsis minima n. sp. is investigated, using live observations, protargol preparations, and molecular data. In living cells, the ranges of cell length are 85–95 μm, cell width 60–70 μm, and oral diameter 40–50 μm. In protargol‐impregnated specimens, cell length ranges between 43 and 71 μm, cell width between 23 and 42 μm, and oral diameter between 13 and 24 μm. The numbers of external oral polykinetids are 12–16 and of somatic kineties are 11–13. There are always two ovoid macronuclei (9–16 × 4–9 μm). Based on the analysis of morphologic data, the new species can be placed in the family Strombidinopsidae, but based on the small subunit rRNA gene sequence data, the Parastrombidinopsis species are more closely associated with strobilidiids and tintinnids.     

极端污染环境下草苷膦抗性菌株HTG7的筛选及其特性研究

从被草苷膦极度污染的土壤中分离到一株极端抗草苷膦菌HTG7,经初步鉴定其为可变盐单胞菌(Halomonas varabilis),该菌株最高可以耐受500mmol／L左右的草苷膦浓度。电镜观察表明,550mmol／L的草苷膦浓度下,细胞大量坏死。生理生化特性表明该菌最适pH为7．0,并且在氯化钠浓度0～10％生长良好。