Alzheimer′s disease (AD) is a kind of cognitive dysfunction disease and β-amyloid (Aβ) generation is crucial for AD pathogenesis and plays a key role in disease progression. A transgenic fly expressing two copies of APP/BACE/DPsn to mimic the pathologic changes of AD might be useful for AD therapeutic drug screening. Using the classic Gal4/UAS system, we constructed the stable transgenic flies expressing two copies of APP/BACE/DPsn genes by consecutive crosses and homologus recombination. Further tests revealed that the lifespan and the medium survival time of flies expressing two copies of APP/BACE/DPsn genes were 52 d and 39 d, respectively, which were much shorter than the lifespan of 69 d and the medium survival time of 49 d of the control flies. Furthermore, the eclosion time of the flies expressing two copies of APP/BACE/DPsn genes was 3 d longer than that of the control flies, and the eclosion rate was 5.2% which was much less than the theoretical value 1∶9 (11%). The results suggest that the elav-Gal driven neuronal expression of two copies of APP/BACE/DPsn genes in flies leads to shorter lifespan and decreases viability of the offspring. These phenotypes of the transgenic fly might be used as a preliminary drug screen model for AD therapy.

 The cadherin-like proteins, located in the brush border membrane vesicles (BBMV) of insect midgut, are major receptors of Bacillus thuringiensis  insecticidal crystal protein. The complete cDNA sequence of cadherin-like protein gene was amplified from the oriental armyworm, Mythimna separata, using RT-PCR and RACE techniques. The full cDNA sequence (named as Msclp, GenBank accession no. JF951432) is 5 642 bp in length, encoding 1 757 amino acid residues, and the deduced amino acid sequence shows typical characteristics of the known insect cadherin proteins, including a signal peptide, a proprotein region, twelve cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. The predicted molecular mass and isoelectric point are 196.786 kD and 4.5, respectively. The cadherin-like protein from M. separata shows the close relationship to cadherin proteins from Helicoverpa assulta, Heliothis virescens, Helicoverpa armigera and Spodoptera exigua, with the amino acid identities of 61.77%, 61.66%, 61.26% and 58.14%, respectively. The real-time RT-PCR results showed that relative expression levels of cadherin-like gene were significantly different in different instars of larvae (P<0.01), which was the highest in the 4th instar larvae and the lowest in the newly-hatched larvae. The cadherin-like gene was majorly expressed in the midgut and very lowly expressed in other parts of the larval body. The results provide the basis for revealing the insecticidal mechanism of Bt to oriental armyworm, and the resistance mechanism of oriental armyworm to Bt.

 In order to investigate the involvement of Bcl-2 family protein in germ cell apoptosis during spermatogenesis and explore the differences of gonad development between reproductive caste and nonreproductive caste in termites, the expression of Bcl-2 and Bax proteins in germ cells during spermatogenesis of reproductives and workers of termite Reticulitermes aculabialis was investigated using immunocytochemical localization method. The results showed that both the immunopositive Bcl-2-like and Bax-like protein existed in germ cells from spermatogonia to sperm stage during spermatogenesis in reproductives and workers. In the reproductives, the expression level of Bcl-2-like was higher in secondary spermatocyte, spermatid and sperm, while lower in spermatogonia and primary spermatocyte. In the workers, a strong expression of Bcl-2-like was shown in secondary spermatocytes, and a lower expression level in spermatogonia and primary spermatocytes. Except for the stage of primary spermatocytes, the expression ratio of Bax-like during spermatogenesis in workers was significantly higher than that in the reproductives. In reproductives, the expression level of Bax-like was higher in spermatogonia, primary spermatocytes and secondary spermatocytes, while the lowest in sperms. Workers had higher expression levels of Bax-like in the secondary spermatocytes, spermatids and sperms, and the lowest expression levels in primary spermaocyte. During spermatogenesis, the expression ratio of Bax/Bcl-2 gradually decreased in germ cells of reproductives. However, in workers the expression ratio only decreased in the secondary spermatocytes and increased in other germ cells. According to the expression ratio of Bax/Bcl-2, spermatogonia and primary spermatocytes were the main targets of apoptosis in reproductives, while in workers the main targets of apoptosis included spermatogonia, primary spermatocytes, spermatids and sperms. The results suggest that in the testis of termite, apoptosis of germ cells is regulated by the pro-and anti-apoptotic members of the Bcl-2 family proteins and the expression of Bcl-2-like and Bax-like show a dynamic change which determines the fate of survival or death of germ cells during spermatogenesis. Bcl-2-like and Bax-like not only play critical roles germ cell apoptosis in the testis, but also can be involved in caste differentiation of termites.

 Insect antimicrobial peptides (AMPs) have wide antimicrobial spectrum. Cloning and prokaryotic expression of antimicrobial peptide TmAMP3 gene from Tenebrio molitor could provide a basis for further application of this antimicrobial peptide. TmAMP3 was amplified by RT-PCR using a pair of specific primers designed according to the relevant nucleotide sequence from GenBank. The gene TmAMP3 was subcloned directionally into the prokaryotic expression vector pET-30a and transformed into Escherichia coli BL21. After IPTG introduction, fusion protein was detected in the supernatant of lysates by SDS-PAGE and purified with nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography matrices, and the fusion protein HIS-TmAMP3 was obtained. In the presence of IPTG, the growth of BL21 transformed by pET30a-TmAMP3 was inhibited. Under conditions of high temperature 100℃ for 10 h and strong acid or alkali, antibacterial activities of the fusion protein still existed. The minimum inhibitory concentration (MIC) of the fusion protein against five bacterial strains was also detected. The experiment offers a theoretical foundation to produce antimrobial peptides with stability on a large scale.

To clarify the relation of the structure of male accessory glands from Gampsocleis gratiosa Brunner von Wattenwyl with their functions, we examined the ultrastructure of male accessory glands using transmission electron microscope, and explored their roles in spermatodesms using differential interference contrast microscope. The results revealed that all gland tubules of the male accessory glands are histologically similar. The epithelium is always monolayered and devoid of cuticular intima, suggesting its mesodermic origin. There are abundant rough endoplasmic reticulum, mitochondria and Golgi bodies in the epithelial cells, displaying features of protein synthesis and secretion. There are four types of secretions in gland lumen, including electron-transparent granules, electrondense granules, fine granular material and villous spherical material. The epithelial cells mainly discharge secretions into the gland lumen by apocrine or merocrine mechanisms. Secretions of short opalescent glands are involved in disorganization of the spermatodesms with ‘cap’, and secretions from long opalescent glands and hyaline glands are important to maintain spermatodesms. The results lay a foundation for further understanding the physiological function of male accessory glands in tettigoniids.

The midgut epithelium of insects is responsible for enzyme production, digestion, and secretion. The proliferation and apoptosis pattern of midgut in Apis mellifera ligustica was comparatively studied by using 5-bromo-2-deoxyuridine (BrdU) incorporation and the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. The results showed that during larval development the midgut size increase resulted from digestive cell proliferation and from the increase of digestive cell number due to differentiation of regenerative cells. During metamorphosis, the larval midgut epithelium degenerated and the pupal epithelial cells due to differentiation of larval regenerative cells replaced the larval epithelial cells. The regenerative cells occurred during the whole developmental stages of the midgut. Regenerative cell proliferation and differentiation result in the growth and change in midgut epithelium of honeybee. This study provides a theoretical basis for apoptosis and autophagy research.

Pistacia chinensis Bunge (Anacardiaceae) produces high-oil fruits and is being evaluated as an important biofuel source through establishing large plantations in China. However, harvest of fruit and oil crops from this tree may be limited by the damage from the seed wasp (Eurytoma plotnikovi Nikolskaya as the specialist seed predator) and seedless fruits (i.e., those parthenocarpic and aborted). In order to assess the impact of predator damage and seedless fruits on fruit and oil yields of this prospective biofuel tree, we quantified crop reduction caused by seedless fruits and seed wasps by estimating fruit and oil production among individual plants of three P. chinensis populations in Mt. Taihang Shan in Jiyuan City, Henan province and also measured fruit oil content for each fate category (i.e., sound, seedless and insect-infested). The results indicated that fruit conditions varied considerably both among individual plants and among populations with the average 53.0% exhibiting seedless fruits and 22.6% showing insectinfested fruits. The dry mass of either seedless (30.7 mg/fruit) or insect-infested (33.1 mg/fruit) fruits was less than half of sound fruits (67.4 mg/fruit), and the oil content was similar between deceptive (3.9%) and insect-infested (3.8%) fruits, but up to ten times lower than that (39.9%) of sound fruits. Based on dry mass and oil content for each fate category, the observed fruit yield (2.9 kg/tree) was reduced up to 50% of the expected (4.7 kg/tree), and the observed oil yield (0.6 kg/tree) was less than one third of the expected (1.9 kg/tree), and fruit and oil yields were similar among populations. Our study indicates that P. chinensis faces serious challenges posed by seedless and insect-infested fruits that need to be overcome before adopting this tree as a major biofuel source.

 A large number of flagellates live in the intestine of lower termites, which is vital for the survival of host termites. Different species of flagellates form a food digestion system to provide nutrients and energy for the host. Studies on the community structure of flagellates will provide the basis for elucidating the physiological functions of each member. Species identification based on morphological characteristics is influenced by the flagellate growth and developmental stages, sample preparation methods and other factors, but molecular biological methods based on molecular markers can avoid these drawbacks in studying complex microbial communities. In this study, the community structure of flagellates in the gut of Coptotermes formosanus was investigated with molecular biological methods combining with morphological characteristics. Three methods were also compared in studying community structure. Three species of flagellates (Pseudotrichonympha grassii, Holomastigotoides mirabile, and Spirotrichonympha leidyi) were identified by optical and scanning electron microscopic observation. Compared with morphological identification, 18S rDNA restriction fragment length polymorphism analysis can reveal more species diversity. Cell counting under optical microscopy is more accurate than 18S rDNA analysis in investigating the amount of each flagellate. The average number of flagellates per termite worker was 780±179 for P. grassii, 1 630±391 for H. mirabile, and 2 950±1 003 for Spirotrichonympha leidyi. This study established a method of combining optical microscopy observation with 18S rDNA analysis to investigate intestinal flagellate community, which is the foundation to clarify the biological functions of the gut symbionts.

Insect expressed sequence tags (ESTs) database provides a valuable resource for developing well-characterized molecular markers. In this study, 1 217 ESTs from the salivary glands of the wheat midge, Sitodiplosis mosellana, were downloaded from NCBI database and assembled into unigenes. The characteristics of unigene-derived SSR were analyzed and partial EST-SSRs were screened. The results showed that 141 EST-SSRs distributed in 106 (10.12%) unigene sequences were detected, with an average of one SSR in every 3.49 kb of unigene sequence. Among 1-6 nucleotide repeat types, 1-3 nucleotide repeats are the main types, accounting for 97.16% of all SSR. A/T, AC/GT and AAC/GTT account for the highest proportion in mononucleotide, dinucleotide and trinucleotide, respectively. Furthermore, EST-SSR primer pairs were designed using the Primer Premier 5.0 program and 26 pairs were selected for marker development in S. mosellana adults. Of the 26 primer pairs, 20 pairs (76.92%) produced discernable polymerase chain reaction (PCR) products, and of these 20 primer pairs, 9 pairs (45%) displayed polymorphism. Fifty-one alleles were found in the 9 primer pairs, the mean number of alleles per locus was 5.67, the average expected heterozygosity was 0.65 and the average polymorphism information content (PIC) was 0.60. The SSRs identified in this study will help explore the population genetic structure and genetic diversity of S. mosellana in the near future.

Ectothermic drosophilids are profoundly affected by thermal selection (i.e., genetic effects) or through induced effects on phenotype (i.e., plasticity). Phenotypic plasticity is a powerful means of adaptation in diverse organisms but has received less attention for different drosophilids. We analyzed reaction norms of melanisation in Drosophila species which differ in developmental thermal range and geographical distribution. D. ananassae and D. jambulina are cold sensitive, and these species can be cultured between 18 to 32℃. By contrast, D. nepalensis is cold-tolerant and heat-sensitive species which can be raised between 12 and 25℃. The cosmopolitan species D. melanogaster has a broader thermal range (13-31℃). Significant differences were observed between reaction norms of melanisation in three anterior vs. three posterior abdominal segments in these species. In D. nepalensis, all the six abdominal segments (2nd-7th) are highly plastic. However, only the last three abdominal segments are plastic in D. melanogaster. In contrast, D. ananassae (a tropical species) lacks plasticity for all abdominal segments. Cosmopolitan species (D. melanogaster), even from much colder climates, does not show darker phenotypes similar to that observed in D. nepalensis. The aim of this study is to understand the processes involved in generating the morphological diversity of color patterns and adaptation of Drosophila species to different geographical regions. Finally, comparing body melanisation patterns to phylogeny suggests recurrent adaptations for genetic polymorphism vs. phenotypic plasticity in different evolutionary lineages.

Insect hemocytes play important roles in the metabolism, metamorphosis and immunity, which are closely related events of growth and development. Because of lack of the adaptive immunity,  immunity functions that the insect hemocytes execute play important roles in combating exogenous pathogens. This review summaries the recent progress in the types of insect hemocytes, hematopoietic organs, haematopoietic stem cells and the regulating factors in insect haematopoiesis. There are three types of hemocytes in Drosophila, while most hemocytes of Lepidoptera and other insect species, can be classified into five types, depending on staining patterns. Insect hemocytes are dispersed in the circulating hemolymph and hematopoietic organs, where the hemocytes can replicate. The two systems are important for the characterization and localization of the hematopoietic stem cells in insects. Blood progenitors which arise from the Drosophila embryonic mesoderm differentiate into various hemocytes, and these processes are controlled by hematopoiesis regulating factors.

The silkworm, Bombyx mori, has a ventral nerve cordtype nervous system, which is more simple in structure than that of vertebrates; however, the simple system controls the complex behavior of the silkworm. Therefore, B. mori is an ideal model animal for neurobiology study. The silkworm nervous system, including the central nervous system, the peripheral nervous system and the sympathetic nervous system, plays a role in the regulation of sight, smell, feeding, cocooning, mating, excretion and other life activities of the silkworm by transferring signals. The genes coding for neurotransmitters, e.g., acetylcholine, γ-aminobutyric acid and dopamine, and neuropeptides, e.g., prothoracicotropic hormone (PTTH) and diapause hormone (DH), were found in the nervous system of the silkworm. The development of the silkworm nervous system is regulated by a variety of genes and MicroRNA, such as bmo-miR-92. At present, the main research methods for silkworm nervous system include electroantennogram, immunocytochemistry, transgenic methods, neuroinformatics, and three-dimensional reconstructions. The research on silkworm nervous system will help to illuminate the signal transmission mechanisms of nervous system and the formation mechanisms of biological neural networks.

 β-tubulin is involved in a variety of functions, such as the development of insect, signal pathway and pesticide resistance. Total RNA was isolated from the 3rd instar larvae of Agrotis ypsilon (Rottemberg), and the full-length cDNA was cloned by RT-PCR and RACE, named as AgTubB (GenBank accession number: JN029962). The mRNA levels were examined in different developmental stages and various organs. β-tubule cDNA sequence, 1 724 bp in length, contains an open reading frame of 1 347 bp, encoding 448 amino acids. The predicted molecular weight of the amino acid is approximately 50.30 kD with an isoelectric point of 4.81. The cloned β-tubulin gene shares the highest identity with that of Helicoverpa armigera (amino acid sequence identity 99.55%), and its amino acid sequences have about 90%-99% identity with other insect tubulins compared. The mRNA levels of β-tubulin gene were constant at different developmental stages and in various organs. The molecular cloning of β-tubulin gene is important for further study on the function of this gene and screening of β-tubulin inhibitors.

 The geomagnetic orientation is one of the important mechanisms for orientation of insects in the long distance migration. In this study, the long-winged and short-winged adults of the brown planthopper, Nilaparvata lugens, were selected to detect magnetic materials using Superconducting Quantum Interference Magnetometer (magnetic field range: ±4.8 mA/m; temperature range: 1.9-400 K) and to ascertain their distribution in the body. The results showed that there was no obvious turning point at T=220 K in temperature-demagnetization curve and no closed hysteresis loop in the whole body of long-winged male adults of N. lugens. Similar phenomena were found in long-winged female adults and short-winged male and female adults, suggesting that the detection of magnetic materials using whole insect body is not obvious. When tested using body segments, the turning points of temperature-demagnetization curves were obviously detected at T=220 K, and hysteresis loops were also clearly closed in the abdomen of long-winged and short-winged adults, suggesting that hysteresis (i.e., coercive force) or magnetic materials exist in the abdomen of N. lugens. In the meantime, there were no closed hysteresis loops detected in the cephalothorax of long-winged and short-winged adults, suggesting that no magnetic materials exist in this body part of N. lugens. The existence of magnetic materials in the body of N. lugens provides physical basis for its geomagnetic orientation during the long distance migration.

 A typical great migration event of rice leaf folder, Cnaphalocrocis medinalis (Guenée), occurred in rice region of southern China and south part of southern Yangtze River during June 10-12, 2010. In order to illustrate the population characteristics of the pest and further reveal the atmospheric dynamic mechanisms of large-scale immigration of C. medinalis, the migration process of C. medinalis and the atmospheric backgrounds that influenced the landing process were analyzed by using HYSPLIT, a trajectory analysis software for the simulation of migration trajectories, GIS (Geographic Information System) and GrADS (Grid Analysis and Display System). We obtained the following results: (1) The population of C. medinalis in northern Guangdong resulted mainly from immigrations, but supplemented by a little local breeding. (2) Southwest of strong low-level jets carried large-scale invasions of C. medinalis into Guangdong. The involuntary landing populations of C. medinalis were caused by rainfall, the immigrants of C. medinalis landed obviously on the marginal rainfall zone such as Qujiang District, Zijin County and Fogang Couty, and the differences of the spatial distribution of the rainfall zone directly resulted in the significant differences of C. medinalis population densities that landed at Qujiang District and Nanxiong City. (3) Simulations of migration trajectories indicated that most of the immigrants came from south-western Guangdong. The double-cropped early season rice of this area with Yangchun City as the representative was in the reproductive stage in early June (flowering and filling stage to milk stage), which was deteriorative for C. medinalis as food, so this area could provide a great amount of emigration moths of C. medinalis to form the large-scale invasion into northern Guangdong.

Lysiphlebus fabarum (Marshall) is one of most important natural enemies of the soybean aphid, Aphis glycines Matsumura. Biological characteristics of L. fabarum including such indices as the developmental duration, breeding potential, longevity and sex ratios, and the emergence, feeding and parasitism behaviors of the parasitoid were observed under the laboratory conditions and described. The results showed that within the temperature of 19-31℃, the developmental duration gradually shortened with the increase of temperature. Most offsprings were produced at 22℃. At 19℃, the female adults had the longest longevity (12.9 d on average) when they were provided with 10% honey water as food. However, when the temperature reached to 31℃, the adult longevity was only 4.0 d. The sex ratio was 1.5∶1 at 19℃, and 1.3∶1 at 22℃; at higher temperatures (25℃, 28℃ and 31℃), however, more males were produced. The emergence period varies from 1.5 h to 3 h. Adult females can copulate and lay eggs on the day of emergence, and they usually choose the 2nd-3rd nymphs of the aphid to parasite. The results will be useful to guide the control of the soybean aphid in fields and provide basic knowledge on mass production, storage and utilization of L. fabarum in future.