Cloning of acetyl CoA carboxylase cDNA and the effects of spirodiclofen on the expression of acetyl CoA carboxylase mRNA in Panonychus citri

The citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), is an important pest worldwide. Previous studies showed that acetyl CoA carboxylase (ACCase) may be a critical target of spirodiclofen, a recently introduced insecticide. Therefore, we cloned the PcACCase gene and obtained a full‐length cDNA (Genbank accession number KJ675439 ). The open reading frame was 6 972 bp, coding for 2 323 amino acids. The PcACCase protein had a theoretical molecular weight of 262.82 kDa and an isoelectric point of 6.31, and it contained six conserved domains and one low‐complexity region. Quantitative real‐time PCR showed that spirodiclofen can up‐regulate the expression levels of ACCase mRNA during all four developmental stages.     

Identification and biochemical characterization of Asp t 36, a new fungal allergen from Aspergillus terreus

Aspergillus terreus is an allergenic fungus, in addition to causing infections in both humans and plants. However, the allergens in this fungus are still unknown, limiting the development of diagnostic and therapeutic strategies. We used a proteomic approach to search for allergens, identifying 16 allergens based on two-dimensional immunoblotting with A. terreus susceptible patient sera. We further characterized triose-phosphate isomerase (Asp t 36), one of the dominant IgE (IgE)-reactive proteins. The gene was cloned and expressed in Escherichia coli. Phylogenetic analysis showed Asp t 36 to be highly conserved with close similarity to the triose-phosphate isomerase protein sequence from Dermatophagoides farinae, an allergenic dust mite. We identified four immunodominant epitopes using synthetic peptides, and mapped them on a homology-based model of the tertiary structure of Asp t 36. Among these, two were found to create a continuous surface patch on the 3D structure, rendering it an IgE-binding hotspot. Biophysical analysis indicated that Asp t 36 shows similar secondary structure content and temperature sensitivity with other reported triose-phosphate isomerase allergens. In vivo studies using a murine model displayed that the recombinant Asp t 36 was able to stimulate airway inflammation, as demonstrated by an influx of eosinophils, goblet cell hyperplasia, elevated serum Igs, and induction of Th2 cytokines. Collectively, our results reveal the immunogenic property of Asp t 36, a major allergen from A. terreus, and define a new fungal allergen more broadly. This allergen could serve as a potent candidate for investigating component resolved diagnosis and immunotherapy.     

中国雄尾螨属一新种及一已知种重描述（蜱螨亚纲：雄尾螨科）

本文记述采自我国湖南的雄尾螨属一新种：凹背雄尾螨，新种Ａｒｒｅｎｕｒｕｓ ｃｕｒｖｉｄｏｒｓａｌｉｓ ｓｐ．ｎｏｖ．。新种以背板前端极度向体内塌陷等为显著特征。另对鱼尾雄尾螨Ａｒｒｅｎｕｒｕｓ ｐｉｓｃｉｓｃａｕｄａｐｅｔｉｏｌａｔｕｓ Ｍａｒｓｈａｌｌ１９２８作了全面的再记述，其鉴定标本采自湖南、湖北。     

Effects of pesticides on spin down and webbing production by the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae)

Spin down in response to pesticides is a known phenomenon. This study aimed at investigating the effects of varying acaricide concentrations and acaricidal combinations on the rate of spin down and thread length, the fate of mites after spinning down and, thus, the implications of spin down in the context of mite control and the relationship between webbing and the efficacy of ovicides. In response to cyhexatin at a concentration of up to 100 mg dm-3 the rate of spin down did not change, but in response to higher concentrations it occurred earlier and ceased before the end of the experiment. The mean thread length did not vary with the concentration of acaricide and, whilst the proportion of mites spinning down increased with a cyhexatin concentration of up to 10 mg dm-3, it did not increase further with higher concentrations thereafter. It is therefore postulated that at any given time only a certain proportion of mites have a propensity to spin down. In combination with cyhexatin, only amitraz (at low concentrations) increased the proportion of mites spinning down, but amitraz (at higher concentrations), flubenzimine and permethrin all inhibited spin down, which may be a useful attribute in pesticide formulations. With regard to the fate of mites after spinning down, they were able to climb back up threads, but the proportion doing so was too small to be of practical importance. Mites which spin down and remain at the end of a thread die, but those which reached another leaf were able to spin down again and were more likely to do so if the leaf bore a cyhexatin residue. Mites reaching another leaf are also able to lay eggs, the number being greater if the leaf which they reach is untreated. Spin down is therefore likely to be of significant advantage to Tetranychus urticae in avoidance of the effects of acaricides. Finally, some eggs were observed to be laid on webbing and not to come into direct contact with clofentezine residues. The use of a fine water spray to simulate dew increased the ovitoxicity of clofentezine, probably by resuspension of the pesticide, but not of amitraz, which inhibits webbing production. The avoidance of acaricides should be added to the several known advantages of webbing production for spider mites. It is concluded that, all other factors being equal, pesticide formulations which inhibit spin down and webbing production are likely to be more effective in control programmes than those which stimulate such behaviour.     

Culturing chelifers (Pseudoscorpions) that consume Varroa mites

Chelifers (Pseudoscorpions) are generalist predators of small prey such as mites. Their occasional presence in honeybee hives suggests potential to exploit them as part of a management programme against Varroa mites (Varroa destructor), a significant pest of honeybees. Two species of native New Zealand chelifers Nesochernes gracilis and Heterochernes novaezealandiae, shown to consume Varroa mites, were collected from commercial nucleus hives or in litter surrounding the hives. Methods for mass‐rearing the chelifers were developed to provide specimens for research and introduction into beehives for biological control of Varroa. Cultures were fed aphids and fruit fly larvae in vented containers containing sand and bark. N. gracilis was maintained at 14°C, 18°C, and 22°C. At 18°C, 1423 nymphs were reared from 140 N. gracilis adults, with 84.8% of all nymphs produced at this temperature. H. novaezealandiae was maintained at 18°C and 22°C, with 5 nymphs raised from 12 adults at 18°C and none at the higher temperature.     

The Comparison of the Properties of Two Lipases from Penicillium cyclopium Westring

Penicillium cyclopium Westring produced two kinds of lipases (EC 3.1.1.3) (A and B). At the begining of the cultivation, activity of B-lipase was detected more than that of A-lipase, though only A-lipase was accumulated at the last stage. The pH stability of B-lipase suggested that the eventual decrease of B-lipase activity was brought about by undesirable pH of culture fluid.

Two lipases were isolated respectively in homogeneous states and characterized. The pI’s of A- and B- lipases were 4.96 and 4.15 and their molecular weights were 27000 and 36000, respectively. In addition, the substrate specificities of two lipases were significantly different from each other.     

The evolution and distribution of Calyptozetes sarekensis (Acari: Oribatei)

Calyptozetes sarekensis , an oribatid mite found predominantly, though not exclusively in lichens, inhabits regions within the arctic circle and subarctically between latitudes 60^o and 70^o (Swedish Lapland, Norway, Bear Island, Spitzbergen, Jan Mayen, Iceland, Greenland, northern Canada). In recent years, however, the species has been recorded from a number of montane sites in Great Britain and southern Europe. There would appear to be only two possible explanations for die discontinuous distribution of this mite. (1) The species has been transported from its main arctic and subarctic area of distribution to its southern montane outposts by some agent (driftwood, birds, wind), or (2) in Britain and southern Europe it represents a relict species of the Ice Age, left stranded on high ground after the final retreat of the ice. Evidence is presented in support of the second hypothesis. In addition, it is suggested that its presence on the different land masses of its main arctic and subarctic range, which are separated from each other by wide stretches of ocean, could be explained by die hypothesis that it is a very ancient species daring from the time Laurasia was in existence some 60 or more million years ago. The alternative hypothesis of transportation of the species between one or more of these areas, however, is by no means ruled out.     

Does Bdellodes lapidaria (Acari: Bdellidae) have a role in biological control of the springtail pest, Sminthurus viridis (Collembola: Sminthuridae) in south-eastern Australia?

Throughout southern Australia, the lucerne flea, Sminthurus viridis (Collembola: Sminthuridae), is an important pest of a variety of winter grain crops and pastures. The predatory mite, Bdellodes lapidaria (Acari: Bdellidae), co-occurs with S. viridis and is reported to be a biological control agent of this pest. Using laboratory bioassays and field experiments, we assessed the susceptibility of B. lapidaria to several pesticides and investigated its impact in controlling S. viridis. In the laboratory, B. lapidaria was found to be susceptible to the synthetic pyrethroids, α-cypermethrin and bifenthrin, but relatively tolerant to the avermectin, abamectin, and organophosphorous chemicals, omethoate and chlorpyrifos. In field experiments, B. lapidaria was not adversely affected by applications of either bifenthrin or omethoate. Despite strong intraspecific interactions, we found no detectable impact of B. lapidaria on S. viridis numbers in the field. These results indicate that B. lapidaria has a relatively high tolerance to several pesticides, perhaps partly through behavioural avoidance, but little impact as a biological control agent on S. viridis in south-eastern Australia.