Cell division and differentiation were processing in quantity from the fertilized eggs to larvae of the silkworm, Bombyx mori, but in diapause eggs embryonic development arrested in the G2 of cell division. In order to explore the molecular regulation in this developmental stage, the cyclin gene of B. mori was cloned according to the cyclin L1 sequence of Homo sapiens and named BmCcnl1. The ORF of BmCcnl1 is 1 254 bp, encoding a 417-amino acid protein and registered with GenBank accession number FJ889988. The predicted molecular weight and isoelectric point of BmCcnl1 protein were 49 kDa and 9.84, respectively analyzed by Protean software. The prokaryotic expression vector pET-21d-BmCcnl1 was constructed, and the expression product was present in inclusion bodies. The expression of the BmCcnl1 mRNA was detected using RT-PCR. The relative expression level of BmCcnl1 mRNA was stable in the embryonic stage of non-diapause eggs, but its expression was not detectable 72 h after oviposition. The results suggest that BmCcnl1 is related to the development regulation of the diapause and non-diapause eggs. The cloning and expression analysis of BmCcnl1 provide the basis for the research of the embryonic development and cell cycle regulation.

To obtain a fullscale assessment of the influences of transgenic Bt crops on the oriental armyworm, Mythimna separata (Walker), larval growth and development, adult reproduction, and flight potential of M. separata were examined when newly hatched larvae continuously fed on artificial diet containing different concentrations of Cry1Ac toxin. The results showed that the mean head capsule width, and body length of the larvae fed with diets containing 0 (CK), 3, 6, 12, 24, 48 and 96 μg/g of Cry1Ac toxin for 6 d were significantly decreased as the concentration of toxin increased. Similarly, body weight, mortality, and the developmental period of the larvae treated for 18 d were negatively and significantly affected as the Cry1Ac dosage increased. The larvae fed with diets containing more than 12 μg/g of Cry1Ac toxin could not pupate, while the larvae fed with diets containing 0, 3 and 6 μg/g of Cry1Ac toxin could pupate and emerge normally. Furthermore, the pupal duration was extended, and the pupation rate decreased significantly as Cry1Ac concentration increased from 0 (CK) to 3, and 6 μg/g. Reproductive potential of the moths resulting from the larvae fed with diets containing 0, 3, and 6 μg/g of Cry1Ac toxin was also significantly different. Preoviposition period of adults was significantly prolonged, and the number of eggs laid per female was significantly decreased as the dosage of Cry1Ac toxin increased. Flight potential (including flight duration, distance, and velocity) of the 1-day-old moths was significantly decreased as the dosage of Cry1Ac toxin increased by tethered-flight test. All these results showed that the Cry1Ac had a significant impact on growth and development, reproduction and flight potential of M. separata, and this will help to improve the evaluation of ecological safety of Bt-crops.

The beet armyworm, Spodoptera exigua (Hübner), is a major agricultural pest in China, which frequently breaks out in many parts of China in the last 20 years. To explore the rule of the population dynamics and to establish the forecasting mode of population trends of S. exigua in quantity, the time series analysis and stepwise regression analysis methods were used for studying the law of wide-area (greater range) atmospheric temperature and rainfall influence on outbreak frequency of S. exigua in China. The results indicated that the wide-area temperature and rainfall had a complex effect on the long-term trends and fluctuations of S. exigua outbreak frequency. During 1979-2008, the frequency of the beet armyworm outbreaks in China showed an upward trend wave, and its average annual growth rate of the outbreak index was 0.076, while the widearea temperature of China (taking the 27 city-level observation points as a statistics example) in the years 1990-2008 increased at the average annual incremental rate of 0.039℃, showing a rising frequency of the beet armyworm outbreak with wide-area temperature rising trend. Ten factors, which had a significant effect (P<0.05 or 0.01) on the regression forecasting model and could be used to forecast quantitatively a wide-area outbreak trend index of S. exigua (the forecast accuracy of the simulation model was more than 99%), were screened out from 52 factors (the temperature and rainfall of the monthly and annual average of January to December of the current year and last year). The author believes that this close relationship between the wide-area temperature, rainfall factors and the beet armyworm outbreak trend index is not a mere coincidence, but a necessary consequence of environments (temperature and rainfall) acting on creatures (beet armyworm).

In order to explore the molecular mechanism of expression and regulation of prophenoloxidase activating proteinase (PAP) in larvae of Ostrinia furnacalis (Guenée), the sequences of conserved regions of PAP genes in different insects were used to design the degenerate primers, and a cDNA fragment with the size of 509 bp encoding 169 amino acids was amplified from the 5th larvae of O. furnacalis by RT-PCR. The fragment has a predicted molecular weight of 18.7 kD and pI value of 5.1. A conserved catalytic triad (H, D, S) in the serine protease like domain was found, but the clip domain did not exist. BlastP analysis showed that the amino acid sequence of the cloned fragment from O. furnacalis had the highest identity (47%) to those of Manduca sexta PAP-3 and Anopheles gambiae Clip B1 protein, and 45%, 45%, 44%, 43% and 41% identity to those of M. sexta PAP-2, Bombyx mori PPAE, Spodoptera litura PPAE-3, Samia cynthia ricini PAP and Drosophila melanogaster serine protease-7, respectively. Phylogenetic analysis showed that the genetic relationship of O. furnacalis, M. sexta PAP-3 and S. litura PPAE-3 was closer, while that of O. furnacalis, Drosophila melanogaster serine protease-7 and Anopheles gambiae Clip B1 protein was more distant. The results suggest that the cloned cDNA fragment of O. furnacalis larvae is a part of the PAP gene nucleotide sequence at the C-terminus.

The endosymbionts Wolbachia can cause various reproductive alterations to their hosts. Previous reports indicate that the mobile genetic elements, insertion sequences (ISs), are widely distributed in Wolbachia genomes and can extensively modify the plasticity, diversity and evolution of the bacterial genome. The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is an alien insect pest of rice in Eastern Asia, which reproduces bisexually in its native regions but reproduces parthenogenetically in all of invaded areas. In this study, by using PCR we cloned two ISs, ISWosp4 and ISWosp6, from the Wolbachia infecting parthenogenetic rice water weevils collected from Tanghai, Hebei, China, and two ISs, ISWosp3 and ISWosp5, from the Wolbachia infecting sexual weevils collected from Texas, USA. Nucleotide sequence alignment suggested that ISWosp3 and ISWosp4 can be grouped to IS3 group in IS3 family, ISWosp5 to IS231 group in IS4 family, and ISWosp6 to IS1031 group in IS5 family. The ORF structure and deduced amino acid sequences of these ISs were analyzed, and ISWosp5 was speculated to have potential transposition activity. The findings can enrich our knowledge on the insertion sequences of IS3, IS4 and IS5 families, and can serve as a basis for future studies concerning interactions of Wolbachia and the rice water weevil.

 Chemical control is the mainly control method for Plutella xylostella (L.) throughout the world. Choosing insecticides with high efficacy on all stages of this pest can help us control it well. In this case, toxicities of indoxacarb and hexaflumuron on eggs, larvae and adults of P. xylostella were studied with leaf dip method. The LC₅₀ values of egg stage for indoxacarb and hexaflumuron were 201.40 and 37.32 mg/L, respectively. Also indoxacarb and hexaflumuron had excellent toxicity on the 3rd larval instar (LC₅₀: indoxacarb=4.82 mg/L, hexaflumuron=1.48 mg/L). Results of moth toxicity indicated that above insecticides had no acceptable toxicity on this insect (LC₅₀: indoxacarb=845.20 mg/L, hexaflumuron=3 438 mg/L). According to the calculated LC₅₀ values, hexaflumuron was more toxic than indoxacarb to eggs and larvae of diamondback moth but at the adult stage the indoxacarb was more toxic.

Bioassay plays an important role in the studies of biology, medicine and toxicology. The time-dose-mortality model (TDM) widely applied to quantitative bioassay data analysis can not construct a unified model for complex bioassay data, and has the disadvantage of utilizing the information incompletely. Based on support vector regression (SVR), a novel quantitative bioassay model has been developed, which can construct a unified model for complex data with different test factors, different test objects and different environment factors. We compared the prediction performance between SVR and TDM using 14 simple data and 2 complex data. The results showed that SVR achieved better precision than TDM not only in self-consistency test but also in jackknife test, implying that the estimated values of LD50 and LT50 by the former are more reliable. As a useful supplement to TDM, SVR has the potential to be widely used for quantitative bioassay data analysis.