Male-killing, a male-specific death of arthropod hosts during development, is induced by
(Mollicutes) endosymbionts of the Citri-Poulsonii and the Ixodetis groups, which are phylogenetically distant ...groups.
induces male-killing in
(Diptera) using the Spaid toxin that harbors ankyrin repeats, whereas little is known about the origin and mechanisms of male-killing induced by
Here, we analyzed the genome and the biological characteristics of a male-killing
strain
Hm in the moth
(Tortricidae, Lepidoptera). Strain
Hm harbored a 2.1 Mb chromosome and two potential plasmids encoding Type IV effectors, putatively involved in virulence and host-symbiont interactions. Moreover,
Hm did not harbor the
gene but harbored 10 ankyrin genes that were homologous to those in other
strains. In contrast to the predominant existence of
in hemolymph, our quantitative PCR assays revealed a systemic distribution of strain
Hm in
, with particularly high titers in Malpighian tubules but low titers in hemolymph. Furthermore, transinfection assays confirmed that strain
Hm can infect cultured cells derived from distantly related insects, namely
(Diptera) and
(Lepidoptera). These results suggest different origins and characteristics of
- and
-induced male-killing.
•Compositional contrast of annular backscattered electron detectors is increased.•The method is based on physical properties of the backscattered electron signal.•Analytical and semi-empirical ...algorithms for realizations are provided.•The proposed method is robust with respect to artifacts.
A method for increasing compositional or material contrast of a standard semiconductor BSE detector in a scanning electron microscope (SEM) by compensation of the topographic contrast component is proposed. Compensation is based on the physical properties of backscattered electron emission and topography information of the specimen's surface.
Three analytical and semi-empirical compensation algorithms employing different physical models and approximations are implemented and compared to conventional BSE signals to show the effectivity of the proposed compensation approach.
The endosymbiotic bacterium Wolbachia occasionally increases host fitness or manipulates host reproductions to enhance vertical transmission. Multiple Wolbachia strains can coinfect the same host ...individual, which alters the density as well as phenotypes of the bacteria. However, the effects of Wolbachia coinfection on host fitness remain largely unknown. Here, we examined the effects of three phylogenetically distinct Wolbachia strains, wHm-a, wHm-b, and wHm-c, on host fitness by comparing non-infected, singly infected, and triply infected Homona magnanima lines within a fixed genetic background. By examining the effects of Wolbachia on host longevity, survivorship, and reproduction, we demonstrated that single infection with either wHm-b or wHm-c reduced host reproduction, but the triple infection led to the highest intrinsic growth rate. Susceptibility to the natural pathogens such as viruses and fungi was not different among the lines regardless of Wolbachia infection status. Cellular and humoral immunities were not affected by Wolbachia in females, whereas phenoloxidase activity was suppressed in males of all Wolbachia-infected lines, implying that it was a result of the mother's curse hypothesis or a strategy of Wolbachia to increase their horizontal transmission efficiency. Although how the host's genetic diversity affects the Wolbachia fitness effects is yet unknown, our findings indicated that the effects of Wolbachia are deeply influenced by infection status and that Wolbachia could change symbiotic strategy depending on host sex and transmission route.
Abstract The decline of wild bee populations causes the decline of bee-pollinated plant populations through the deterioration of pollination services. Since high bee species richness generally ...involves high functional group diversity, protecting areas of high bee species richness will help to maintain pollination services for plants. However, those areas do not always include the habitats of bee species with specialized functions that expand the range of plants being pollinated. To map important areas for protecting native bee species and their functions, we estimated the distributions and functional range of 13 bumble bee species and 1 honey bee species in Japan. The distributions were estimated from an ensemble of six species distribution models using bee occurrence data and environmental data. The functional range of bee species was estimated by combining the estimated distributions and proboscis length, which frequently corresponds to the floral shape of the plant species they pollinate. The estimated species richness was high in western Hokkaido and the estimated functional range was wide in central Honshu. Our method is useful to see whether areas important for high species richness of pollinators differ from those for rare species or their functions.
Abstract
Bumblebees are important pollinators of wild and agricultural plants but recently have been declining due to various stressors, such as pesticides and diseases. Because of the haplo-diploid ...sex determination system in hymenopterans, experiments using micro-colonies (small sub colonies without a queen) to identify risks to bumblebee health are limited as they are only able to produce males. Therefore, an experimental protocol for rearing bumblebee larvae in vitro is needed to better understand effects on worker larvae. Here, we aimed to establish a rearing method for larvae of
Bombus terrestris
for use in risk assessment assays. To confirm the validity of our rearing method, we tested two insecticides used for tomato cultivation, chlorfenapyr and dinotefuran.
Bombus terrestris
larvae fed with a high nutrient quantity and quality diet increased growth per day. All chlorfenapyr-exposed individuals died within 10 days at 2000-fold dilution, an application dose used for tomatoes. There were significant differences in adult emergence rate among almost all chlorfenapyr treatments. On the other hand, sublethal dinotefuran-exposure did not affect rates of pupation and adult emergence, growth, or larval and pupal periods. Although larvae were smaller than in the natural colony, this rearing method for
B. terrestris
larvae proved to be effective at evaluating realistic sub-colonies to pesticide exposures.
Kisspeptin, encoded by the Kiss1 gene, has attracted attention as a key candidate neuropeptide in controlling puberty and reproduction via regulation of gonadotrophin‐releasing hormone (GnRH) ...secretion in mammals. Pioneer studies with Kiss1 or its cognate receptor Gpr54 knockout (KO) mice showed the indispensable role of kisspeptin‐GPR54 signalling in the control of animal reproduction, although detailed analyses of gonadotrophin secretion, especially pulsatile and surge‐mode of luteinising hormone (LH) secretion, were limited. Thus, in the present study, we have generated Kiss1 KO rats aiming to evaluate a key role of kisspeptin in governing reproduction via pulse and surge modes of GnRH/LH secretion. Kiss1 KO male and female rats showed a complete suppression of pulsatile LH secretion, which is responsible for folliculogenesis and spermatogenesis, and an absence of puberty and atrophic gonads. Kiss1 KO female rats showed no spontaneous LH/follicle‐stimulating hormone surge and an oestrogen‐induced LH surge, suggesting that the GnRH surge generation system, which is responsible for ovulation, does not function without kisspeptin. Furthermore, challenge of major stimulatory neurotransmitters, such as monosodium glutamate, NMDA and norepinephrine, failed to stimulate LH secretion in Kiss1 KO rats, albeit they stimulated LH release in wild‐type controls. Taken together, the results of the present study confirm that kisspeptin plays an indispensable role in generating two modes (pulse and surge) of GnRH/gonadotrophin secretion to regulate puberty onset and normal reproductive performance. In addition, the present study suggests that kisspeptin neurones play a critical role as a hub integrating major stimulatory neural inputs to GnRH neurones, using newly established Kiss1 KO rats, which serve as a useful model for detailed analysis of hormonal profiles.
Summary
To investigate the clinical significance of soluble tumour necrosis factor receptor (sTNF‐R) II/I ratio as an indicator of the diagnosis of macrophage activation syndrome (MAS) complicating ...systemic juvenile idiopathic arthritis (s‐JIA), we measured the serum sTNF‐RI and II levels in 117 patients with s‐JIA, including 29 patients with MAS, 15 with Epstein–Barr virus‐induced haemophagocytic lymphohistiocytosis (EBV‐HLH), 15 with Kawasaki disease (KD) and 28 healthy controls (HCs). We determined their correlation with measurements of disease activity and severity. Furthermore, we measured serum interleukin (IL)‐18 levels in patients with EBV‐HLH and compared these in levels in patients with MAS. The sTNF‐RII/I ratio was elevated significantly in MAS and EBV‐HLH patients compared with those in the acute phase of s‐JIA and KD patients, whereas there were no significant differences between HCs and those in the acute phase of s‐JIA. The sTNF‐RII/I ratio increased profoundly as MAS developed and correlated positively with disease activity. Serum IL‐18 levels were elevated significantly in MAS patients compared with EBV‐HLH patients. The monitoring of serum IL‐18 and sTNF‐RII/I might be useful for the diagnosis of MAS and the differentiation between MAS and EBV‐HLH.
This article accompanies the following article: Weaver LK. Combining multiple biomarkers differentiates between active SJIA, SJIA‐MAS and EBV‐HLH. Clin Exp Immunol 2018; 191:253–4.
Serum sTNFRII/I ratio is a useful marker for assessing the transition to MAS from acute phase of systemic JIA.
Serum sTNFRII/I ratio correlated positively with disease activity of MAS.
The monitoring of serum IL‐18 and sTNFRII/I might be useful for the diagnosis of MAS and the differentiation between MAS and EBVHLH.
Male killing (MK) is a type of reproductive manipulation induced by microbes, where sons of infected mothers are killed during development. MK is a strategy that enhances the fitness of the microbes, ...and the underlying mechanisms and the process of their evolution have attracted substantial attention. Homona magnanima, a moth, harbors two embryonic MK bacteria, namely,
(
) and
(
), and a larval MK virus, Osugoroshi virus (OGV; Partitiviridae). However, whether the three distantly related male killers employ similar or different mechanisms to accomplish MK remains unknown. Here, we clarified the differential effects of the three male killers on the sex-determination cascades and development of
males. Reverse transcription-PCR demonstrated that
and
, but not OGVs, disrupted the sex-determination cascade of males by inducing female-type splice variants of
(
), a downstream regulator of the sex-determining gene cascade. We also found that MK microbes altered host transcriptomes in different manners;
impaired the host dosage compensation system, whereas
and OGVs did not. Moreover,
and
, but not OGVs, triggered abnormal apoptosis in male embryos. These findings suggest that distantly related microbes employ distinct machineries to kill males of the identical host species, which would be the outcome of the convergent evolution.
Many microbes induce male killing (MK) in various insect species. However, it is not well understood whether microbes adopt similar or different MK mechanisms. This gap in our knowledge is partly because different insect models have been examined for each MK microbe. Here, we compared three taxonomically distinct male killers (i.e.,
,
, and a partiti-like virus) that infect the same host. We provided evidence that microbes can cause MK through distinct mechanisms that differ in the expression of genes involved in sex determination, dosage compensation, and apoptosis. These results imply independent evolutionary scenarios for the acquisition of their MK ability.
Wolbachia are inherited intracellular bacteria that cause male-specific death in some arthropods, called male-killing. To date, three Wolbachia strains have been identified in the oriental tea ...tortrix Homona magnanima (Tortricidae, Lepidoptera); however, none of these caused male-killing in the Japanese population. Here, we describe a male-killing Wolbachia strain in Taiwanese H. magnanima. From field-collected H. magnanima, two female-biased host lines were established, and antibiotic treatments revealed Wolbachia (wHm-t) as the causative agent of male-killing. The wsp and MLST genes in wHm-t are identical to corresponding genes in the nonmale-killing strain wHm-c from the Japanese population, implying a close relationship of the two strains. Crossing the Japanese and Taiwanese H. magnanima revealed that Wolbachia genotype rather than the host genetic background was responsible for the presence of the male-killing phenotype. Quantitative PCR analyses revealed that the density of wHm-t was higher than that of other Wolbachia strains in H. magnanima, including wHm-c. The densities of wHm-t were also heterogeneous between host lines. Notably, wHm-t in the low-density and high-density lines carried identical wsp and MLST genes but had distinct lethal patterns. Furthermore, over 90% of field-collected lines of H. magnanima in Taiwan were infected with wHm-t, although not all host lines harboring wHm-t showed male-killing. The host lines that showed male-killing harbored a high density of Wolbachia compared to the host lines that did not show male-killing. Thus, the differences in the phenotypes appear to be dependent on biological and genetic characteristics of closely related Wolbachia strains.
In this paper, we present a new computational method for automatically tracing high‐resolution photographs to create expressive line drawings. We define expressive lines as those that convey ...important edges, shape contours, and large‐scale texture lines that are necessary to accurately depict the overall structure of objects (similar to those found in technical drawings) while still being sparse and artistically pleasing. Given a photograph, our algorithm extracts expressive edges and creates a clean line drawing using a convolutional neural network (CNN). We employ an end‐to‐end trainable fully‐convolutional CNN to learn the model in a data‐driven manner. The model consists of two networks to cope with two sub‐tasks; extracting coarse lines and refining them to be more clean and expressive. To build a model that is optimal for each domain, we construct two new datasets for face/body and manga background. The experimental results qualitatively and quantitatively demonstrate the effectiveness of our model. We further illustrate two practical applications.
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