Wang Zhiying

A modified one-step procedure for rapid RNA isolation from insect

A modified guanidinium isothiocyanate method was used to extract total RNA from two forest insect species Clostera anastomosis and Saperda populnea. The integrity of RNA was demonstrated by the methods of gel electrophoresis and cDNA analysis. Typical A260/A280 absorbance ratio of the total RNA was in range of 1.8 to 2.0. The size of double strand cDNAs obtained by RT-PCR was more than 2 kb, which indicated that intact mRNA was obtained. The fragments of β-actin and chitinase gene from the RNA of C. anastomosis were obtained by RT-PCR, which indicated that the RNA could be used for other molecular operation. By this procedure, RNAs could be extracted and analyzed by electrophoresis from at least 8 samples within 4 hours. These results showed that this method was time-and cost-saving and effective.

Bioassay of Clostera anastomosis Granulosis virus

The second-instar healthy larvae of Clostera anastomosis were collected in the artificial woodland of poplar in Shuangcheng Town, Heilongjiang Province, China. The dead larvae of C. anastomosis infected by granulosis virus (GV) of Clostera anastomosis were grinded to obtain GV. The GV viral pesticide was diluted to seven concentrations, 1.58×103PIB·mL−1, 1.58×104 PIB·mL−1, 1.58×105 PIB·mL−1, 1.58×106 PIB·mL−1, 1.58×107 PIB·mL−1, 1.58×108 PIB·mL−1 and 1.58×109 PIB·mL−1 and the fresh poplar leaves were dipped in the seven concentrations liquids to feed the larvae. After nine days the mortality of larvae was investigated. The minimum corrected mortality (7.32%) of larvae was observed at concentrations of 1.58×103PIB·mL−1 and the maximal mortality (97.36%) was observed at concentration of 1.58×109 PIB·mL−1. The regression equation between the logarithm of the virus concentration and the mortality was y=1.946+0.558x. The LC50 was 2.97×105PIB·mL−1. The LT50 for the virus concentration of 1.58×105, 1.58×106, 1.58×107, 1.58×108, 1.58×109 PIB·mL−1 were 8.55d, 6.89d, 5.9d, 4.65d, and 4.08d, respectively, shorting gradually with the concentration increasing. It is concluded that the toxicity of Clostera anastomosis GV is very strong and as a kind of insecticides it has big potential in practical application.

Study on histopathology of nuclear polyhedrosis virus ofZethenia rufescentaria Motsch

This paper reports the histological observation of larvae ofZethenia rufescentaria Motsch. after infection by ZrNPV. Histopathologic study revealed that ZrNPV were multiplied within the nuclear of fat body, epidermis cell, midgut cell, tracheal matrix and blood cell. These cells showed obvious cytopathic effects. The nucleus of infected cells underwent swelled. Under electron microscope, virus and polyhedral of ZrNPV were clearly observed in these nucleus of infected cells. The nucleus of susceptible tissues were fulfilled with polyhedra after 70–140 h.

New cell line establishment of a cell line from embryos ofDendrolimus superans

A new cell line was established from 5-day-old embryonated eggs ofDendrolimus superans and has been designated NEAU-Ds-950821. The cell line consists of mixture of cell types, including majority of spherical shaped cells and a few of spindle shaped cells. The cell line has a population of doubling time of 52.6 h. Chromosome analysis revealed typical lepidopteran chromosomes. Isozyme characterization of Esterase showed the patterns were different from other three cell lines (Ms-927311, Xc-920730, and SF-21AE). Virus infectivity tests revealed the cell line can supportD. superans cytoplasmic polyhedrosis virus.

A study on the winter hardiness and the energy resources of overwintering ofScambus sp

In Honghuaerji region,Scambus sp. is an effective natural enemy of the mongolian scotch pine cone weevil (Pissodes validiirostriis Gyll). The percentage of parasitism on larvae of the mongolian scotch pine cone weevil amounts to 20 to 30% commonly, sometimes as high as 45% or more, thus significantly regulating the weevil population. But the high mortality of larvae ofScambus in winter, which according to the surveys (conducted in 1986, 1987, and 1988) were 24.00%, 51.03% and 47.70% respectively, seriously influenced the natural suppression effect. In order to reveal the cause of winter death of this natural enemy, from 1990 authors studied the winter physiological indices, cold hardiness and overwintering protection ofScambus larvae, in the purpose of providing scientific basis of usingScambus in biological control.