The diving beetles of Kamchatka, with additional records from Sakhalin and the Kuril Islands (Coleoptera: Dytiscidae).

Die Dytiscidenfauna der nordostasiatischen Halbinsel Kamtschatka wird auf der Grundlage von Literaturnachweisen und neueren Aufsammlungen zusammengestellt. Die folgenden zehn Arten werden erstmals für Kamtschatka nachgewiesen: Hygrotus marklini (Gyllenhal), Hydroporus notabilis LeConte, H. submuticus Thomson, H. tristis (Paykull), H. uenoi Nakane, Oreodytes okulovi Lafer, Agabus balkei Fery & Nilsson, A. discolor Harris, Ilybius chishimanus Kôno, Rhantus suturellus (Harris), und Graphoderus perplexus Sharp. Insgesamt 38 Dytiscidenarten, davon 22 mit holarktischer Verbreitung, sind nun von Kamtschatka bekannt. Graphoderus perplexus wird erstmals aus der Paläarktis nachgewiesen. Weitere Nachweise werden für Sachalin und die Kurilen genannt. Die folgenden Arten sind Erstnachweise für Sachalin: Hydroporus nigellus Mannerheim, Agabus kholini Nilsson, Ilybius angustior (Gyllenhal), und Acilius canaliculatus (Nicolai). Zehn Arten werden erstmals für die Kurilen nachgewiesen: Hydroporus nigellus, H. notabilis, H. submuticus, H. tristis, Agabus clypealis (Thomson), A. confinis (Gyllenhal), A. costulatus (Motschulsky), A. discolor, Ilybius discedens Sharp, und Colymbetes dahuricus Aubé. Neun dieser Arten wurden auf den nördlichen, H. tristis dagegen auf den südlichen Kurilen gefunden. Damit sind jetzt von Sachalin 39 und von den Kurilen 36 Arten bekannt.The dytiscid fauna of the north-east Asian peninsula Kamchatka is reviewed based on literature records and more recent collections. The following ten species are here reported from Kamchatka for the first time: Hygrotus marklini (Gyllenhal), Hydroporus notabilis LeConte, H. submuticus Thomson, H. tristis (Paykull), H. uenoi Nakane, Oreodytes okulovi Lafer, Agabus balkei Fery & Nilsson, A. discolor Harris, Ilybius chishimanus Kôno, Rhantus suturellus (Harris), and Graphoderus perplexus Sharp. Altogether 38 species of Dytiscidae are now known from Kamchatka, and of these 22 have Holarctic distributions. Graphoderus perplexus is here reported for the Palearctic Region for the first time. Additional records are given for Sakhalin and the Kuril Islands. The following four species are here reported from Sakhalin for the first time: Hydroporus nigellus Mannerheim, Agabus kholini Nilsson, Ilybius angustior (Gyllenhal), and Acilius canaliculatus (Nicolai). The following ten species are here reported from the Kuril Islands for the first time: Hydroporus nigellus, H. notabilis, H. submuticus, H. tristis, Agabus clypealis (Thomson), A. confinis (Gyllenhal), A. costulatus (Motschulsky), A. discolor, Ilybius discedens Sharp, and Colymbetes dahuricus Aubé. Nine of the species were found in the North Kurils, whereas H. tristis was found in the South Kurils. With these additions, 39 species are now known from Sakhalin, and 36 from the Kuril Islands

Community-wide benefits of targeted indoor residual spray for malaria control in the Western Kenya Highland

<p>Abstract</p> <p>Background</p> <p>Interest in indoor residual spray (IRS) has been rekindled in recent years, as it is increasingly considered to be a key component of integrated malaria management. Regular spraying of each human dwelling becomes less and less practical as the control area increases. Where malaria transmission is concentrated around focal points, however, targeted IRS may pose a feasible alternative to mass spraying. Here, the impact of targeted IRS was assessed in the highlands of western Kenya.</p> <p>Methods</p> <p>Indoor residual spray using lambda-cyhalothrin insecticide was carried out during the last week of April 2005 in 1,100 targeted houses, located in the valley bottom areas of Iguhu village, Kakamega district of western Kenya. Although the uphill areas are more densely populated, valleys are believed to be malaria transmission hotspots. The aim of the study was to measurably reduce the vector density and malaria transmission in uphill areas by focusing control on these hotspots. A cohort of 1,058 children from 1-5 yrs of age was randomly selected from a 4 km by 6 km study area for the baseline malaria prevalence survey after pre-clearing malaria infections during the third week of April 2005, and the prevalence of <it>Plasmodium </it>infections was tested bi-weekly. Seasonal changes in mosquito densities 12 months before the IRS and 12 months after the IRS was monitored quarterly based on 300 randomly selected houses. Monthly parasitological surveys were also carried out in the same area with 129-661 randomly selected school children of age 6-13 yrs.</p> <p>Results</p> <p>The result of monthly parasitological surveys indicated that malaria prevalence in school children was reduced by 64.4% in the intervention valley area and by 46.3% in the intervention uphill area after 12 months of follow-ups in contrast to nonintervention areas (valley or uphill). The cohort study showed an average of 4.5% fewer new infections biweekly in the intervention valley compare to nonintervention valley and the relative reduction in incidence rate by week 14 was 65.4%. The relative reduction in incidence rate in intervention uphill by week 14 was 46.4%. <it>Anopheles gambiae </it>densities were reduced by 96.8% and 51.6% in the intervention valley and intervention uphill, respectively, and <it>Anopheles funestus </it>densities were reduced by 85.3% and 69.2% in the intervention valley and intervention uphill, respectively.</p> <p>Conclusion</p> <p>Vector control had significant indirect impact on the densely populated uphill areas when IRS was targeted to the high-risk valleys. Additionally, the wide-reaching benefits of IRS in reducing vector prevalence and disease incidence was observed for at least six months following spraying, suggesting targeted IRS as an effective tool in malaria control.</p

Predatory capacity of a shorefly, Ochthera chalybescens, on malaria vectors

<p>Abstract</p> <p>Background</p> <p>Since <it>Ochthera chalybescens </it>had been reported to prey on African malaria vectors, the predatory capacity of adults of this species on <it>Anopheles gambiae </it>sensu stricto was explored.</p> <p>Method</p> <p>Predatory capacity of this fly on <it>A. gambiae </it>s.s. was tested at all developmental stages, including the adult stage in the laboratory setting. Effects of water depth on its predatory capacity were also examined.</p> <p>Results</p> <p>This study revealed that <it>O. chalybescens </it>preyed on mosquitoes at all life stages except eggs. It was able to prey on an average of 9.8 to 18.8 mosquito larvae in 24 hrs. Mosquito larva size and water depth did not affect predatory capacity. However, the predacious fly preyed on significantly more 2^nd-instar larvae than on pupae when larvae and pupae were both available.</p> <p>Conclusion</p> <p><it>Ochthera chalybescens </it>is, by all indications, an important predator of African malaria vectors.</p

Extracellular vesicles synchronize cellular phenotypes of differentiating cells

細胞外小胞が細胞の分化を同調させる現象の発見. 京都大学プレスリリース. 2021-10-01.Cells act in unison when next to each other. 京都大学プレスリリース. 2021-10-01.During embryonic development, cells differentiate in a coordinated manner, aligning their fate decisions and differentiation stages with those of surrounding cells. However, little is known about the mechanisms that regulate this synchrony. Here we show that cells in close proximity synchronize their differentiation stages and cellular phenotypes with each other via extracellular vesicle (EV)-mediated cellular communication. We previously established a mouse embryonic stem cell (ESC) line harbouring an inducible constitutively active protein kinase A (CA-PKA) gene and found that the ESCs rapidly differentiated into mesoderm after PKA activation. In the present study, we performed a co-culture of Control-ESCs and PKA-ESCs, finding that both ESC types rapidly differentiated in synchrony even when PKA was activated only in PKA-ESCs, a phenomenon we named ‘Phenotypic Synchrony of Cells (PSyC)’. We further demonstrated PSyC was mediated by EVs containing miR-132. PKA-ESC-derived EVs and miR-132-containing artificial nano-vesicles similarly enhanced mesoderm and cardiomyocyte differentiation in ESCs and ex vivo embryos, respectively. PSyC is a new form of cell-cell communication mediated by the EV regulation of neighbouring cells and could be broadly involved in tissue development and homeostasis

Unforeseen misuses of bed nets in fishing villages along Lake Victoria

<p>Abstract</p> <p>Background</p> <p>To combat malaria, the Kenya Ministry of Health and nongovernmental organizations (NGOs) have distributed insecticide-treated nets (ITNs) for use over beds, with coverage for children under five years of age increasing rapidly. Nevertheless, residents of fishing villages have started to use these bed nets for drying fish and fishing in Lake Victoria. This study investigated the extent of bed net misuse in fishing villages.</p> <p>Methods</p> <p>Seven fishing villages along the lake were surveyed to estimate how widely bed nets were being used for fishing and drying fish. Villagers were asked why they used the bed nets for such purposes.</p> <p>Results</p> <p>In total, 283 bed nets were being used for drying fish. Of these, 239 were long-lasting insecticidal bed nets (LLIN) and 44 were non-long-lasting insecticidal bed nets (NLLIN). Further, 72 of the 283 bed nets were also being used for fishing. The most popular reasons were because the bed nets were inexpensive or free and because fish dried faster on the nets. LLINs were preferred to NLLINs for fishing and drying fish.</p> <p>Conclusion</p> <p>There is considerable misuse of bed nets for drying fish and fishing. Many villagers are not yet fully convinced of the effectiveness of LLINs for malaria prevention. Such misuses may hamper the efforts of NGOs and governmental health organizations.</p

Landscape determinants and remote sensing of anopheline mosquito larval habitats in the western Kenya highlands

BACKGROUND: In the past two decades the east African highlands have experienced several major malaria epidemics. Currently there is a renewed interest in exploring the possibility of anopheline larval control through environmental management or larvicide as an additional means of reducing malaria transmission in Africa. This study examined the landscape determinants of anopheline mosquito larval habitats and usefulness of remote sensing in identifying these habitats in western Kenya highlands. METHODS: Panchromatic aerial photos, Ikonos and Landsat Thematic Mapper 7 satellite images were acquired for a study area in Kakamega, western Kenya. Supervised classification of land-use and land-cover and visual identification of aquatic habitats were conducted. Ground survey of all aquatic habitats was conducted in the dry and rainy seasons in 2003. All habitats positive for anopheline larvae were identified. The retrieved data from the remote sensors were compared to the ground results on aquatic habitats and land-use. The probability of finding aquatic habitats and habitats with Anopheles larvae were modelled based on the digital elevation model and land-use types. RESULTS: The misclassification rate of land-cover types was 10.8% based on Ikonos imagery, 22.6% for panchromatic aerial photos and 39.2% for Landsat TM 7 imagery. The Ikonos image identified 40.6% of aquatic habitats, aerial photos identified 10.6%, and Landsate TM 7 image identified 0%. Computer models based on topographic features and land-cover information obtained from the Ikonos image yielded a misclassification rate of 20.3–22.7% for aquatic habitats, and 18.1–25.1% for anopheline-positive larval habitats. CONCLUSION: One-metre spatial resolution Ikonos images combined with computer modelling based on topographic land-cover features are useful tools for identification of anopheline larval habitats, and they can be used to assist to malaria vector control in western Kenya highlands