Seasonal occurrence and development of three closely related Oligonychus species (Acari: Tetranychidae) and their associated natural enemies on fagaceous trees.

We compared the life cycles and diapause attributes among three closely related spider mites, Oligonychus castaneae on Castanea crenata, and O. gotohi and O. amiensis on Lithocarpus edulis. The lower thermal thresholds from egg to egg were 10.5, 8.5 and 8.9 °C, respectively, and the thermal constants were 177.8, 229.5 and 232.5 degree-days, respectively. The cumulative hatching rates of diapause eggs of O. castaneae and O. gotohi increased as the season progressed in and after early-to-mid January, which indicates diapause termination. In contrast, O. amiensis showed higher hatching rates in December and January, but hatchability gradually decreased in and after February because some of the eggs died from the cold. Oligonychus castaneae and O. gotohi females produced diapause eggs in response to the short photoperiod in late September to early October and in early-to-late October, respectively, which corresponded to the times predicted by the critical photoperiods (at 15 °C) of 12 h 15 min and 11 h 15 min for the respective species. Oligonychus castaneae showed at least a single population peak over the 3-year observation period, but the time of peak population varied from mid-July to mid-September. The population of O. gotohi was higher between November and May when diapause eggs were present on host plants in early winter and the first-generation females laid eggs on leaves in spring. The population of O. amiensis, which is a non-diapause species, was only high between September and December, because eggs were laid on leaves in autumn to winter and then gradually disappeared and/or died during winter. Natural enemies were observed as the number of spider mites declined, and the density suppression effect by natural enemies was confirmed in the field.

Effects of Wolbachia/Cardinium Infection on the Mitochondrial Phylogeny of Oligonychus castaneae (Acari: Tetranychidae).

A wide range of invertebrates harbor intracellular endosymbiotic bacteria. Within these endosymbionts, Wolbachia and Cardinium, have been attracting particular attention because these bacteria frequently affect the genetic structure and genetic diversity of their hosts. They cause various reproductive alterations such as cytoplasmic incompatibility, parthenogenesis induction, male-killing, and feminization. Through these alterations, they also affect the maternally inherited organelles of their hosts. Mitochondrial DNA (mtDNA) can be used for molecular phylogenetic analysis of invertebrates. However, in Wolbachia- or Cardinium-infected invertebrates, phylogenetic trees based on mtDNA are often inconsistent with those based on nuclear DNA. In the present study, we determined the Wolbachia/Cardinium infection status of 45 populations of the mite, Oligonychus castaneae Ehara & Gotoh (Acari: Tetranychidae), collected throughout Japan. Then, we compared phylogenetic trees of O. castaneae based on both the cytochrome c oxidase subunit I (COI) gene of mtDNA and the 28S rRNA gene of nuclear DNA to clarify the effects of Wolbachia and/or Cardinium infection. We found 106 Wolbachia-infected individuals and 250 Cardinium-infected individuals in a total of 450 individuals, indicating an infection rate of 79%. No double-infected individuals were observed. In the 28S tree, almost all populations formed a single group. In the COI tree, O. castaneae formed four separate groups that more closely followed Wolbachia/Cardinium infection than geographic distribution. These results strongly suggest that the endosymbionts affected mitochondrial variation of O. castaneae.

Effect of temperature on diapause termination and post-diapause development in Eotetranychus smithi (Acari: Tetranychidae).

Previous studies on the spider mite Eotetranychus smithi Pritchard & Baker have shown that diapause in eggs is induced by low temperature alone and that females developed at ≤ 17.5 °C laid diapause eggs, regardless of the photoperiod. In this study, diapause eggs were kept at 5 °C and a photoperiod of 16L:8D for 0-120 days and then maintained at 25 °C to know the effect of chilling on diapause termination. Diapause eggs mostly hatched when they were maintained at 25 °C after chilling for 30-90 days at 5 °C, which suggests that diapause termination is favored by low temperatures. To clarify the hatching conditions after diapause termination, diapause eggs kept at 5 °C for 45 days were subsequently maintained at various constant temperatures (from 15 to 25 °C) under a long-day photoperiod (16L:8D). The hatchability at all temperatures tested was high (> 90%) and did not significantly differ among the high temperatures. Duration of embryonic development was shorter with increasing warming temperature after chilling. The lower thermal threshold (t) and thermal constant (k) for post-diapause egg development were 10.5 °C and 76.9 degree-days, respectively. Females, which developed from diapause eggs that were chilled at 5 °C for 45 days and then maintained at 15 °C, laid only non-diapause eggs, which indicates that they were prevented from re-entering diapause even under diapause-inducing conditions (15 °C). Thus, temperature is the main factor to control diapause termination and post-diapause development, which has also been found for other spider mites that enter diapause at the egg stage.

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Factors influencing bovine intramuscular adipose tissue development and cellularity.

Appearance, distribution, and amount of intramuscular fat (IMF), often referred to as marbling, are highly variable and depend on environmental and genetic factors. On the molecular level, the concerted action of several drivers, including hormones, receptors, transcription factors, etc., determines where clusters of adipocytes arise. Therefore, the aim of future studies remains to identify such factors as biological markers of IMF to increase the ability to identify animals that deposit IMF early in age to increase efficiency of high-quality meat production. In an attempt to unravel the cellular development of marbling, we investigated the abundance of markers for adipogenic differentiation during fattening of cattle and the transcriptome of muscle and dissected IMF. Markers of different stages of adipogenic differentiation are well known from cell culture experiments. They are usually transiently expressed, such as delta-like homolog 1 (DLK1) that is abundant in preadipocytes and absent during differentiation to mature adipocytes. It is even a greater challenge to detect those markers in live animals. Within skeletal muscles, hyperplasia and hypertrophy of adipocytes can be observed throughout life. Therefore, development of marbling requires, on the cellular level, recruitment, proliferation, and differentiation of adipogenic cells to store excess energy in the form of lipids in new cells. In a recent study, we investigated the localization and abundance of early markers of adipogenic differentiation, such as DLK1, in bovine muscle tissue. An inverse relationship between IMF content and number of DLK1-positive cells in bovine muscle was demonstrated. Considering the cellular environment of differentiating adipocytes in muscle and the secretory action of adipocytes and myocytes, it becomes obvious that cross talk between cells via adipokines and myokines may be important for IMF development. Secreted proteins can act on other cells, inhibiting or stimulating their function via autocrine and paracrine actions. Such factors with potential influence on IMF, among them, agouti signaling protein and thrombospondin 4, were identified in transcriptome analyses and further investigated. Furthermore, results from transcriptome analysis indicate involvement of genes that are not directly related to adipogenesis and lipid metabolism, providing new candidates for future research.

Impact of constant versus fluctuating temperatures on the development and life history parameters of Tetranychus urticae (Acari: Tetranychidae).

The impact of daily temperature fluctuations on arthropod life history parameters is inadequately studied compared with the ample amount of research that has been conducted on the effects of constant temperatures. Fluctuating temperatures are likely to be more realistic, as they are ecologically more similar to what these arthropods experience in nature. Here, we compared the impact of 11 constant temperatures that ranged from 10 to 35 °C with fluctuating temperatures with the same corresponding mean temperature and an amplitude of 10 °C between high (12 h) and low (12 h) temperatures on the development and life history parameters of Tetranychus urticae under continuous light conditions. No eggs hatched at constant 10 °C, whereas 81.5% of eggs successfully completed development at fluctuating 10 °C (15/5 °C). Egg-to-female adult development was faster under fluctuating temperatures from 12.5 to 27.5 °C than under constant temperatures, whereas the opposite trend was observed at >30 °C. The lower thermal thresholds (T) were 11.63 and 8.63 °C, and thermal constants (K) were 127.81 and 150.69 degree-days for egg-to-female adults at constant and fluctuating temperatures, respectively. The numbers of oviposition days were significantly higher at fluctuating 15 °C than at the corresponding constant temperature, whereas the opposite trend was observed from 20 to 30 °C. The intrinsic rate of increase (r) was higher at fluctuating than at constant 15 °C. The net reproductive rate (R 0) was also higher at fluctuating than at constant 15 and 35 °C, but showed an opposite trend at 20 and 25 °C. We conclude that fluctuating temperatures should be considered to accurately predict spider mite population dynamics in nature.

Modeling the Effects of Constant and Variable Temperatures on the Vital Rates of an Age-, Stage-, and Sex-Structured Population by Means of the SANDY Approach.

We present a general and flexible mathematical model (called SANDY) that can be used to describe many biological phenomena, including the phenology of arthropods. In this paper, we demonstrate how the model can be fitted to vital rates (i.e., rates associated with development, survival, hatching, and oviposition) of the two-spotted spider mite (Tetranychus urticae (Koch)) exposed to different constant temperatures ranging from 15°C to 37.5°C. SANDY was incorporated into an age-, stage- and sex-structured dynamic model, which was fitted to cohort life-tables of T. urticae conducted at five constant temperatures (15, 20, 25, 30, and 35°C). Age- and temperature-dependent vital rates for the three main stages (eggs, immatures, and adults) constituting the life-cycle of mites were adequately described by the SANDY model. The modeling approach allows for simulating the growth of a population in a variable environment. We compared the predicted net reproductive rate (R0) and intrinsic rate of natural increase (rm) at fluctuating temperatures with empirical values obtained from life-table experiments conducted at temperatures that changed with a daily amplitude (±0, ±3, ±6, ±9, and ±12°C) around an average of 22°C. Results show that R0 decreases with increasing amplitude, while rm is more robust to variable temperatures. An advantage of SANDY is that the same simple mathematical expression can be applied to describe all the vital rates. Besides, the approach is not confined to modeling the influence of a single factor on population growth but allows for incorporating the combined effect of several limiting factors, provided that the combined effect of the factors is multiplicative.

Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km.

We have demonstrated a direct frequency comparison between two 87Sr lattice clocks operated in intercontinentally separated laboratories in real time. Two-way satellite time and frequency transfer technique, based on the carrier-phase, was employed for a direct comparison, with a baseline of 9000 km between Japan and Germany. A frequency comparison was achieved for 83,640 s, resulting in a fractional difference of (1.1±1.6)×10⁻¹5, where the statistical part is the largest contributor to the uncertainty. This measurement directly confirms the agreement of the two optical frequency standards on an intercontinental scale.

Myostatin alters glucose transporter-4 (GLUT4) expression in bovine skeletal muscles and myoblasts isolated from double-muscled (DM) and normal-muscled (NM) Japanese shorthorn cattle.

The purpose of this study was to determine whether myostatin alters glucose transporter-4 (GLUT4) expression in bovine skeletal muscles and myoblasts isolated from double-muscled (DM) and normal-muscled (NM) Japanese Shorthorn cattle. Plasma concentrations of glucose were lower in DM cattle than in NM cattle (P < 0.01). The expression of GLUT4 messenger RNA (mRNA) in the skeletal muscle ex vivo and in myoblasts at 72 h after differentiation in vitro was higher in DM cattle than in NM cattle (P < 0.01). In contrast, the NM and DM cattle did not differ with respect to skeletal muscle expression of GLUT1 and myocyte enhancer factor-2c (MEF2c), a transcription factor of GLUT4. In differentiated myoblasts, the expression of GLUT1, GLUT4, and MEF2c mRNAs was greater in DM cattle than in NM cattle (P < 0.01). In the presence and absence of insulin, glucose uptake in myoblasts was increased in DM cattle relative to that of NM cattle (P < 0.01). The addition of myostatin decreased the expression of GLUT4 and MEF2c mRNAs in DM myoblasts (P < 0.05). Results of the present study suggest that myostatin inhibits the expression of GLUT4 mRNA possibly via MEF2c and that the greater ability of the DM cattle to produce muscle relative to the NM cattle may be due to their greater sensitivity to insulin and greater use of glucose.

Bioactivity of natural O-prenylated phenylpropenes from Illicium anisatum leaves and their derivatives against spider mites and fungal pathogens.

A variety of volatile phenylpropenes, C6-C3 compounds are widely distributed in the plant kingdom, whereas prenylated phenylpropenes are limited to a few plant species. In this study, we analysed the volatile profiles from Illicium anisatum leaves and identified two O-prenylated phenylpropenes, 4-allyl-2-methoxy-1-[(3-methylbut-2-en-1-yl)oxy]benzene [O-dimethylallyleugenol (9)] and 5-allyl-1,3-dimethoxy-2-(3-methylbut-2-en-1-yl)oxy]benzene [O-dimethylallyl-6-methoxyeugenol (11)] as major constituents. The structure-activity relationship of a series of eugenol derivatives showed that specific phenylpropenes, including eugenol (1), isoeugenol (2) and 6-methoxyeugenol (6), with a phenolic hydroxy group had antifungal activity for a fungal pathogen, whereas guaiacol, a simple phenolic compound, and allylbenzene had no such activity. The eugenol derivatives that exhibited antifungal activity, in turn, had no significant toxicant property for mite oviposition. Interestingly, O-dimethylallyleugenol (9) in which the phenolic oxygen was masked with a dimethylallyl group exhibited a specific, potent oviposition deterrent activity for mites. The sharp contrast in structural requirements of phenylpropenes suggested distinct mechanisms underlying the two biological activities and the importance of a phenolic hydroxy group and its dimethylallylation for the structure-based design of new functional properties of phenylpropenes.

DNA-based identification of spider mites: molecular evidence for cryptic species of the genus Tetranychus (Acari: Tetranychidae).

Spider mites are difficult to identify because they are very small and have a limited number of diagnostic characters. Most species of the spider mite genus Tetranychus in Japan are morphologically similar, differing only in the diameter of the aedeagal knob in males. Because this genus contains many important pests, the unambiguous identification of species is crucial for effective pest management and quarantine procedures. DNA-based methods could complement the morphological methods. We examined whether Tetranychus species in Japan could be identified by DNA sequences using the internal transcribed spacer region of nuclear ribosomal DNA and the cytochrome c oxidase subunit I gene of mitochondrial DNA. We determined sequences of the 13 known Tetranychus species in Japan. We could identify 10 of the 13 species in the internal transcribed spacer tree. In the cytochrome c oxidase subunit I tree, we could identify all 13 known Tetranychus species in Japan. Although Tetranychus kanzawai Kishida and T. parakanzawai Ehara were identified by DNA sequences, they were clearly separated into two monophyletic clades each, indicating that a cryptic species existed in each species.

Effect of nutrient intake on intramuscular glucose metabolism during the early growth stage in cross-bred steers (Japanese Black male × Holstein female).

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism-related genes in skeletal muscle of cross-bred cattle. From 1.5 to 5 months of age, group H (n=7) animals were intensively fed a high-protein and low-fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n=7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high-nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real-time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3-kinase (PI-3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin-independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin-dependently mediated glucose uptake in LT of cattle.

Local flow structure of turbulence in three, four, and five dimensions.

Probability density functions (PDF's) of the eigenvalues of the strain tensor of an incompressible isotropic turbulence in 3, 4, and 5 dimensions are computed by direct numerical simulation of Navier-Stokes equations. The PDF's of the smallest (negative) eigenvalue are found to be wider than those of the other ones in all dimensions and to be very insensitive to the dimension. In any dimension, the eigenvalues other than the lowest one increase as the lowest one decreases, so that they tend to be positive for the large magnitude of the lowest eigenvalue. In such a situation the flow comes in along a single direction and comes out in the other directions, which is consistent with the dynamics of the Burgers turbulence in d dimensions. It is suggested that a driving motor of most intermittent turbulent structure is the compression along a single direction. For the velocity 2 form the conditional averages of the enstrophy and the total squared strain in three dimensions are computed as functions of the smallest eigenvalue and found to be monotonically increasing as the magnitude of the smallest eigenvalue increases. Also, it is found that PDF of the source term of the Poisson equation for the pressure is positively skewed but tends to be symmetric with increase of the spatial dimension. Dimension effects on the dynamics of the most compressible eigenvalue are argued.

Molecular-based identification and phylogeny of Oligonychus species (Acari: Tetranychidae).

The genus Oligonychus has been morphologically divided into two groups based on the direction of curvature of the aedeagus and includes some morphologically similar species that are difficult to distinguish. To develop DNA-based methods for identifying Oligonychus species and to determine the phylogenetic relationships among them, we examined the cytochrome c oxidase subunit I gene of mitochondrial DNA and the internal transcribed spacer and 28S regions of nuclear ribosomal RNA gene for 17 species. Based on the genetic distances (p-distances) of the three DNA regions, the range of intraspecific divergence was found to be below (and not overlap) the range of interspecific divergence, which allowed the 17 species to be discriminated correctly, consistent with their classification based on morphology. Phylogenetic trees constructed by neighbor-joining and Bayesian methods clearly showed two clades, consisting of species whose aedeagi curve ventrally and dorsally, respectively. Three Oligonychus species inhabiting gramineous plants formed clearly defined subclades.

Deletion of C/EBP homologous protein (Chop) in C57Bl/6 mice dissociates obesity from insulin resistance.

AIMS/HYPOTHESIS: Endoplasmic reticulum (ER) stress has been implicated in the development of type 2 diabetes, via effects on obesity, insulin resistance and pancreatic beta cell health. C/EBP homologous protein (CHOP) is induced by ER stress and has a central role in apoptotic execution pathways triggered by ER stress. The aim of this study was to characterise the role of CHOP in obesity and insulin resistance. METHODS: Metabolic studies were performed in Chop ( -/- ) and wild-type C57Bl/6 mice, and included euglycaemic-hyperinsulinaemic clamps and indirect calorimetry. The inflammatory state of liver and adipose tissue was determined by quantitative RT-PCR, immunohistology and macrophage cultures. Viability and absence of ER stress in islets of Langerhans was determined by electron microscopy, islet culture and quantitative RT-PCR. RESULTS: Systemic deletion of Chop induced abdominal obesity and hepatic steatosis. Despite marked obesity, Chop ( -/- ) mice had preserved normal glucose tolerance and insulin sensitivity. This discrepancy was accompanied by lower levels of pro-inflammatory cytokines and less infiltration of immune cells into fat and liver. CONCLUSIONS/INTERPRETATION: These observations suggest that insulin resistance is not induced by fat accumulation per se, but rather by the inflammation induced by ectopic fat. CHOP may play a key role in the crosstalk between excessive fat deposition and induction of inflammation-mediated insulin resistance.

Technical note: Determination of cell-specific gene expression in bovine skeletal muscle tissue using laser microdissection and reverse-transcription quantitative polymerase chain reaction.

Skeletal muscle is a very heterogeneous tissue consisting of diverse cell types with specific transcription profiles. Therefore, the measured mRNA abundance of a certain cell type marker is influenced by the transcriptional activity as well as by the usually unknown number of contributing cells in the sample. In studies on the transcriptional activity of adipogenic genes, as indicators for the development of intramuscular adipocytes, an altered number of adipocytes or respective progenitor cells can mask changes in transcriptional activity. To overcome this problem, we started to use laser microdissection to isolate RNA of adipocytes and muscle fibers separately for downstream analysis. Even muscle fiber types can be collected and analyzed separately. Laser microdissection in combination with biopsy techniques enables gene expression studies of particular cell types during the life cycle of an animal. First experiences using laser microdissection for adipogenic gene expression studies in bovine skeletal muscle are described, and the influence of sample preparation and future challenges are discussed.

Cellular conditions for intramuscular fat deposition in Japanese Black and Holstein steers.

The experiment was conducted to study the development of intramuscular fat in Japanese Black (JB) compared to Holstein (HS) steers and to find breed differences for fat depot development and distribution in the carcass under equal feeding conditions. Additional to slaughter samples, biopsy samples of longissimus muscle (LM) and subcutaneous fat, taken at 10, 14, 18, and 22 months of age, were used for histological and molecular investigations. Japanese Black steers stored about 14% more fat in the LM (P = 0.001), resulting in larger marbling flecks (P < 0.001). Muscle fibers and intramuscular adipocytes in both breeds responded to the high energy feeding with significant enlargement, which was faster in JB. Histograms of intramuscular adipocytes size showed a shift toward larger cells during growth, but also the abundance of small, developing adipocytes. This development was accompanied by a correlated up-regulation of adipogenic genes until 22 months of age.

Differentially expressed genes in silkworm cell cultures in response to infection by Wolbachia and Cardinium endosymbionts.

Wolbachia and Cardinium are bacterial endosymbionts that are widely distributed amongst arthropods. Both cause reproductive alterations, such as cytoplasmic incompatibility, parthenogenesis and feminization. Here we studied differentially expressed genes in Wolbachia- and Cardinium-infected Bm-aff3 silkworm cells using a silkworm microarray. Wolbachia infection did not alter gene expression or induce or suppress immune responses. In contrast, Cardinium infection induced many immune-related genes, including antimicrobial peptides, pattern recognition receptors and a serine protease. Host immune responses differed, possibly because of the different cell wall structures of Wolbachia and Cardinium because the former lacks genes encoding lipopolysaccharide components and two racemases for peptidoglycan formation. A few possibly non-immune-related genes were differentially expressed, but their involvement in host reproductive alteration was unclear.

A comparative study of development and demographic parameters of Tetranychus merganser and Tetranychus kanzawai (Acari: Tetranychidae) at different temperatures.

We investigated the effect of temperature on development and demographic parameters such as the intrinsic rate of natural increase (r (m)) of the two spider mite species Tetranychus merganser Boudreaux and T. kanzawai Kishida at eleven constant temperatures ranging from 15 to 40°C at intervals of 2.5°C. Both male and female T. merganser and T. kanzawai completed development from egg to adult at temperatures ranging from 15 to 37.5°C. The longest developmental duration of immature stages was found at 15°C and the shortest developmental duration was found at 35°C for both species. Using linear and non-linear developmental rate models, the lower thermal thresholds for egg-to-adult (female and male) and egg-to-egg development were estimated as 12.2-12.3°C for T. merganser and as 10.8°C for T. kanzawai. The highest developmental rates were observed at around 35°C, whereas the upper developmental thresholds were around 40°C for both species. In fact, at 40°C, a few eggs of either species hatched, but no larvae reached the next stage. The r (m)-values of T. merganser ranged from 0.072 (15°C) to 0.411 day(-1) (35°C), whereas those of T. kanzawai ranged from 0.104 (15°C) to 0.399 (30°C). The r (m)-values were higher for T. kanzawai than for T. merganser at temperatures from 15 to 30°C, but not at 35°C (0.348 day(-1)). Total fecundity of T. merganser was also higher than that of T. kanzawai at 35°C. These results indicate that higher temperatures favor T. merganser more than T. kanzawai.

Reproductive performance of seven strains of the tomato red spider mite Tetranychus evansi (Acari: Tetranychidae) at five temperatures.

The tomato red spider mite Tetranychus evansi Baker et Pritchard occurs on solanaceous plants, and causes serious damage to a variety of crops in Africa and Europe. In 2001 this species was also found in Japan, on nightshade (Solanum nigrum L.), and its invasion to solanaceous of agricultural importance is feasible. To evaluate its potential severity as a pest, the present study assessed the life-history parameters, such as the rate of development and the intrinsic rate of natural increase (r(m)), on S. nigrum for T. evansi collected on seven sites worldwide. Increasing temperatures between 15 and 32.5°C significantly increased the developmental rate of the seven strains while immature developmental duration was about the same at 32.5-40°C. The rate of egg-to-adult development [(% hatch) × (% survival)] exceeded 88% at temperatures between 15 and 37.5°C. The lower thermal thresholds (LT) were 11.9-12.5°C for both egg-to-adult and egg-to-egg development. The optimum developmental temperatures ranged from 36.7 to 43.8°C and the upper developmental threshold (UT) ranged from 45.2 to 59.4°C. The r (m)-values became higher with temperature increasing from 15 to 35°C. The r (m)-values at 25°C ranged from 0.265 to 0.277 which are relatively high for species of the genus Tetranychus. These results indicate that T. evansi after invasion into Japan has the potential to become a serious pest on solanaceous crops, just the same as in Africa and Europe.

Role of arginine in superficial wound healing in man.

Arginine supplementation has been identified as advantageous in experimental wound healing. However, the mechanisms underlying this beneficial effect in tissue repair remain unresolved. Animal studies suggest that the beneficial role of arginine supplementation is mediated, at least in part through NO. The latter component mediates processes involved in tissue repair, including angiogenesis, epithelialization and collagen formation. This prospective study is performed to investigate arginine metabolism in acute surgical wounds in man. Expression of enzymes, known to be involved in arginine metabolism, was studied in donor sites of skin grafts of 10 hospitalized patients undergoing skin transplantation. Plasma and wound fluid levels of arginine metabolites (ornithine, citrulline, nitrate and nitrite = NOx) were measured using High Performance Liquid Chromatography. Expression of iNOS, eNOS, arginase-1 and arginase-2 was studied by immunohistochemistry in paraffin sections of skin tissue. Arginase-1 concentration was measured in plasma and wound fluid using ELISA. Arginase-2 was determined using Western blot analysis. We observed increased levels of citrulline, ornithine, NOx and arginase-1 in wound fluid when compared with plasma. Arginase-2 was expressed in both plasma and wound fluid and seemed higher in plasma. iNOS was expressed by neutrophils, macrophages, fibroblasts, keratinocytes and endothelial cells upon wounding, whereas eNOS reactivity was observed in endothelial cells and fibroblasts. Arginase-1 was expressed in neutrophils post-wounding, while arginase-2 staining was observed in endothelial cells, keratinocytes, fibroblasts, macrophages and neutrophils. For the first time, human data support previous animal studies suggesting arginine metabolism for an NO- as well as arginase-mediated reparation of injured skin.