The first detection of avian haemosporidia from Culicoides biting midges in Japan, with notes on potential vector species and the transmission cycle.

BACKGROUND: Biting midges (Ceratopogonidae) are capable of transmitting a variety of pathogens including viruses, trypanosomes and haemosporidia. The majority of Haemoproteus parasites are transmitted by biting midges predominantly of the genus Culicoides and are known to cause significant physical and reproductive impacts on both wild and domestic birds. In Japan, Haemoproteus had been detected from various avian hosts, but not from arthropod vectors. In this study, we investigated the prevalence of avian haemosporidia at an educational forest in central Japan in attempt to reveal possible vector species of Haemoproteus, which would help to better understand the transmission cycle of Haemoproteus within Japan and to develop preventative measures for captive and domestic birds. METHODS: Biting midges were caught using UV light traps from 2016 to 2018. The collected samples were morphologically identified, and haemosporidian parasites were detected using PCR-based methods. The detected lineages were phylogenetically analyzed and compared with lineages previously detected from birds. Bloodmeal analyses were also carried out for part of the blood-fed individuals. RESULTS: Six Haemoproteus lineages were detected from 17 of 1042 female Culicoides (1.63%), including three species (C. sigaensis, C. arakawae, and C. pictimargo) in which Haemoproteus was detected for the first time. All detected lineages were placed in the subgenus Parahaemoproteus clade and were previously detected from crows of central Japan, strongly suggesting that parasites of these genetic lineages are transmitted between Culicoides and crows. Two Plasmodium lineages were also detected but are thought to be transmitted between Culex mosquitoes and birds of the educational forest based on previous detections. No amplifications were seen in bloodmeal analysis, possibly due to insufficient amount of blood, denaturation via digestion, or insufficient detectability of the used protocol. CONCLUSION: Haemoproteus DNA was detected from Culicoides for the first time in Japan, suggesting that transmission is possible within the country. These findings highlight the necessity to investigate Culicoides populations and Haemoproteus infections dynamics in Japan. However, vector competence could not be confirmed in this study and further studies are anticipated.

Plantar flexor strength at different knee positions in older and young males and females.

INTRODUCTION: This study examined the effects of age and knee position (fully extended, K0; 90° flexed, K90) on plantar flexor maximal voluntary contraction (MVC) torque and the rate of torque development (RTD) in both sexes. METHODS: The following parameters were measured in 32 older (66-81 yr, 17 males and 15 females) and 37 young (20-30 yr, 18 males and 19 females) adults: evoked peak twitch torque, time to peak twitch torque, RTD of the twitch torque, MVC torque, RTD at early (0-50 ms, RTD0-50) and later (100-200 ms, RTD100-200) time intervals during explosive contractions, voluntary activation (VA%) during MVC, root mean square of the electromyogram (RMS-EMG) during MVC and explosive contractions, thickness of the triceps surae, and pennation angle of the medial gastrocnemius. The magnitudes of the differences were interpreted based on Cohen's d (d). RESULTS: Age-related difference in RTD0-50 was greater for females (d = 1.36) than males (d = 1.03) and vice versa for MVC torque and RTD100-200. For young adults, MVC torque, RTDs, and RMS-EMGs of the gastrocnemius but not the soleus were significantly higher in K0 than in K90. For older adults, no differences in voluntary RTDs were observed between K0 and K90, and RMS-EMGs of the gastrocnemius were higher in K90 than in K0, except for that of the lateral gastrocnemius in the early time intervals during explosive contraction. The age-related difference in the effect of knee position for RTD0-50 was higher in females than males, and vice versa for MVC torque and RTD100-200. CONCLUSION: The results suggested that the effects of age and knee joint angle on the plantar flexor performance were more prominent in the early phase of force production for females and were more apparent in the later phase and maximal force for males.

Glucose-conjugated chicken myofibrillar proteins derived from random-centroid optimization present potent hydroxyl radical scavenging activity.

The optimal conditions for the preparation of glucose-conjugated chicken myofibrillar proteins (Mfs) via the Maillard reaction, presenting strong antioxidant activity against hydroxyl radicals (ï½¥OH) and high solubility in low ionic strength medium, were sought using random-centroid optimization (RCO). Four parameters of temperature, relative humidity (RH), reaction time, and glucose-to-Mfs mixing ratio, were examined, resulting in a total of 24 vertices. Evaluations were carried out relatively to each individual vertex, and the optimal preparatory conditions to obtain the highest antioxidant activity were determined as follows: temperature of 52 °C, RH of 38%, reaction time of 6.79 h, and a glucose to Mfs mixing ratio of 11.7 (w/w). The resulting glucose-conjugated chicken Mfs gained thermal gel-forming ability and its ï½¥OH averting capacity reached 9.7 ± 0.7 µmol of gallic acid equivalent/g of protein.Abbreviations: GA: gallic acid; HORAC: hydroxyl radical averting capacity; IC50: half-maximal inhibitory concentration; 2-ME, 2-mercaptoethanol; Mfs: myofibrillar proteins; MHC: myosin heavy chain; ï½¥OH: hydroxyl radical; PAGE: polyacrylamide gel electrophoresis; RCO: random-centroid optimization; RH: relative humidity; RLU: relative light units; SDS: sodium dodecyl sulfate; SEM: scanning electron microscope; SS: disulfide.

Effects of sex and joint action on voluntary activation.

The current study tested the hypothesis that voluntary activation during maximal voluntary contraction (MVC) conditionally depends on sex and joint action. Twenty-eight healthy adults (14 of each sex) performed knee extensor MVC and plantar flexor MVC at extended and flexed knee positions. Voluntary activation during MVC was assessed using a twitch interpolation technique. The voluntary activation during plantar flexor MVC at the extended knee position was significantly lower (P = 0.020, 95% confidence interval 1.4 to 14.6, Cohen's d for between-subject design = 0.94) in women (88.3% ± 10.0%) than in men (96.2% ± 6.6%). In contrast, no significant sex differences were shown in the voluntary activation during knee extensor MVC (93.7% ± 5.9% (women) vs. 95.0%  ± 3.9% (men)) and during plantar flexor MVC at the flexed knee position (90.4% ± 12.2% (women) vs. 96.8% ± 5.6% (men)). The voluntary activation during knee extensor MVC was significantly higher (P = 0.001, 95% confidence interval 2.1 to 8.8, Cohen's d for within-subject design = 0.69) than that during plantar flexor MVC at the extended knee position in women, whereas the corresponding difference was not observed in men. The results revealed that the existence of sex difference in the voluntary activation during MVC depends on joint action and joint angle.

Muscle size-strength relationship including ultrasonographic echo intensity and voluntary activation level of a muscle group.

This study aimed to investigate the relationship between muscle volume (MV) and joint torque for the plantar flexors (PF) in 40 young (20 men and 20 women) and 33 elderly (19 men and 14 women) individuals in consideration of the voluntary activation (VA) of PF and ratio of intramuscular adipose tissue within PF assessed by ultrasonographic echo intensity (EI). MV was estimated from the thickness of PF on ultrasonography and the lower leg length using a prediction equation previously reported. The maximal voluntary contraction torque of isometric plantar flexion was measured as TQMVC. VA (%) was assessed using the twitch interpolation technique, and maximal joint torque calculated by TQMVC/VA × 100 was adopted as TQ100%. The correlation coefficients between MV and TQMVC (r = 0.518) and between MV and TQ100% (r = 0.602) were both significant, with the latter being significantly higher than the former. When a stepwise multiple regression analysis using MV and EI as independent variables and TQ100% as the dependent variable was performed, MV (ß = 0.554) and EI (ß = -0.203) were both selected as significant contributors for estimating TQ100%. Additionally, the residual errors of TQ100% using the multiple regression equation (independent variables: MV and EI; 18.6 ±â€¯14.4 Nm) were significantly lower than those using the simple regression equation (independent variable: MV; 36.6 ±â€¯28.0 Nm). These results suggest that the consideration of VA and EI with muscle size results in a closer muscle size-strength relationship than previously achieved.

Prostaglandin E(2) enhances IL-33 production by dendritic cells.

While interleukin (IL)-33, a novel member of the IL-1 family, seems to promote T helper type 2 (Th2)-associated inflammations and allergic diseases, the stimulating factors for IL-33 production are less well characterized. Prostaglandin E(2) (PGE(2)) has been shown to suppress immune cell functions. However, the immune enhancement by this mediator is not well understood. In the present study, we examined the effect of PGE(2) on IL-33 production by dendritic cells (DCs). Bone marrow-derived DCs were stimulated with lipopolysaccharide (LPS) in the presence or absence of PGE(2). LPS increased mRNA expression of the IL-1 family members, IL-1, IL-18, and IL-33 in DCs. PGE(2) alone showed slight effect on IL-1, IL-18, and IL-33 mRNA expression in DCs. Of note, LPS combined with PGE(2) caused in a synergistic enhancement of mRNA expression of IL-33 but not IL-1 and IL-18. In addition, PGE(2) dramatically enhanced IL-33 protein production by DCs upon LPS stimulation. The protein kinase A (PKA) inhibitor H89 significantly inhibited the PGE(2)-mediated enhancement of IL-33 production by DCs. Thus, PGE(2) appears to enhance IL-33 mRNA expression and its protein synthesis via PKA pathway in DCs. PGE(2) may promote Th2-mediated inflammations through the enhancement of IL-33 production by DCs, which might be associated with the pathogenesis of allergic diseases.