Next-Generation Sequencing Reveals Recent Horizontal Transfer of a DNA Transposon between Divergent Mosquitoes

Horizontal transfer of genetic material between complex organisms often involves transposable elements (TEs). For example, a DNA transposon mariner has been shown to undergo horizontal transfer between different orders of insects and between different phyla of animals. Here we report the discovery and characterization of an ITmD37D transposon, MJ1, in Anopheles sinensis. We show that some MJ1 elements in Aedes aegypti and An. sinensis contain intact open reading frames and share nearly 99% nucleotide identity over the entire transposon, which is unexpectedly high given that these two genera had diverged 145–200 million years ago. Chromosomal hybridization and TE-display showed that MJ1 copy number is low in An. sinensis. Among 24 mosquito species surveyed, MJ1 is only found in Ae. aegypti and the hyrcanus group of anopheline mosquitoes to which An. sinensis belongs. Phylogenetic analysis is consistent with horizontal transfer and provides the basis for inference of its timing and direction. Although report of horizontal transfer of DNA transposons between higher eukaryotes is accumulating, our analysis is one of a small number of cases in which horizontal transfer of nearly identical TEs among highly divergent species has been thoroughly investigated and strongly supported. Horizontal transfer involving mosquitoes is of particular interest because there are ongoing investigations of the possibility of spreading pathogen-resistant genes into mosquito populations to control malaria and other infectious diseases. The initial indication of horizontal transfer of MJ1 came from comparisons between a 0.4x coverage An. sinensis 454 sequence database and available TEs in mosquito genomes. Therefore we have shown that it is feasible to use low coverage sequencing to systematically uncover horizontal transfer events. Expanding such efforts across a wide range of species will generate novel insights into the relative frequency of horizontal transfer of different TEs and provide the evolutionary context of these lateral transfer events

Genome-wide regulation of innate immunity by juvenile hormone and 20-hydroxyecdysone in the Bombyx fat body

<p>Abstract</p> <p>Background</p> <p>Insect innate immunity can be affected by juvenile hormone (JH) and 20-hydroxyecdysone (20E), but how innate immunity is developmentally regulated by these two hormones in insects has not yet been elucidated. In the silkworm, <it>Bombyx mori</it>, JH and 20E levels are high during the final larval molt (4 M) but absent during the feeding stage of 5^thinstar (5 F), while JH level is low and 20E level is high during the prepupal stage (PP). Fat body produces humoral response molecules and hence is considered as the major organ involved in innate immunity.</p> <p>Results</p> <p>A genome-wide microarray analysis of <it>Bombyx </it>fat body isolated from 4 M, 5 F and PP uncovered a large number of differentially-expressed genes. Most notably, 6 antimicrobial peptide (AMP) genes were up-regulated at 4 M versus PP suggesting that <it>Bombyx </it>innate immunity is developmentally regulated by the two hormones. First, JH treatment dramatically increased AMP mRNA levels and activities. Furthermore, 20E treatment exhibited inhibitory effects on AMP mRNA levels and activities, and RNA interference of the 20E receptor <it>EcR</it>-<it>USP </it>had the opposite effects to 20E treatment.</p> <p>Conclusion</p> <p>Taken together, we demonstrate that JH acts as an immune-activator while 20E inhibits innate immunity in the fat body during <it>Bombyx </it>postembryonic development.</p

Molecular guidance cues in the development of visual pathway

ABSTRACT 70%–80% of our sensory input comes from vision. Light hit the retina at the back of our eyes and the visual information is relayed into the dorsal lateral geniculate nuclei (dLGN) and primary visual cortex (V1) thereafter, constituting the image-forming visual circuit. Molecular cues are one of the key factors to guide the wiring and refinement of the image-forming visual circuit during pre- and post-embryonic stages. Distinct molecular cues are involved in different developmental stages and nucleus, suggesting diverse guidance mechanisms. In this review, we summarize molecular guidance cues throughout the image-forming visual circuit, including chiasm determination, eye-specific segregation and refinement in the dLGN, and at last the reciprocal connections between the dLGN and V1

Existence of Prophenoloxidase in Wing Discs : A Source of Plasma Prophenoloxidase in the Silkworm, Bombyx mori

In insects, hemocytes are considered as the only source of plasma prophenoloxidase (PPO). PPO also exists in the hemocytes of the hematopoietic organ that is connected to the wing disc of Bombyx mori. It is unknown whether there are other cells or tissues that can produce PPO and release it into the hemolymph besides circulating hemocytes. In this study, we use the silkworm as a model to explore this possibility. Through tissue staining and biochemical assays, we found that wing discs contain PPO that can be released into the culture medium in vitro. An in situ assay showed that some cells in the cavity of wing discs have PPO1 and PPO2 mRNA. We conclude that the hematopoietic organ may wrongly release hemocytes into wing discs since they are connected through many tubes as repost in previous paper. In wing discs, the infiltrating hemocytes produce and release PPO probably through cell lysis and the PPO is later transported into hemolymph. Therefore, this might be another source of plasma PPO in the silkworm: some infiltrated hemocytes sourced from the hematopoietic organ release PPO via wing discs

Reciprocal Connections Between Cortex and Thalamus Contribute to Retinal Axon Targeting to Dorsal Lateral Geniculate Nucleus

The dorsal Lateral Geniculate Nucleus (dLGN) is the primary image-forming target of the retina and shares a reciprocal connection with primary visual cortex (V1). Previous studies showed that corticothalamic input is essential for the development of thalamocortical projections, but less is known about the potential role of this reciprocal connection in the development of retinal projections. Here, we show a deficit of retinal innervation in the dLGN around E18.5 in Tra2 beta conditional knockout (cKO) cortexless mice, an age when apoptosis occurs along the thalamocortical tract and in some dLGN neurons. In vivo electrophysiology experiments in the dLGN further confirmed the loss of functional retinal input. Experiments with N-methyl-d-aspartic acid-induced V1 lesion as well as Fezf2 cKO mice confirmed that the disruption of connections between the dLGN and V1 lead to abnormal retinal projections to the dLGN. Interestingly, retinal projections to the ventral Lateral Geniculate Nucleus (vLGN) and Superior Colliculus (SC) were normal in all 3 mice models. Finally, we show that the cortexless mice had worse performance than control mice in a go-no go task with visual cues. Our results provide evidence that the wiring of visual circuit from the retina to the dLGN and V1 thereafter is coordinated at a surprisingly early stage of circuit development

The Relationship Between Humor Styles and Life Satisfaction

Šī pētījuma mērķis bija izpētīt vai un kā ar apmierinātību ar dzīvi saistīti dažādi humora stili. Pētījumā piedalījās 423 respondenti vecumā no 16 - 72 gadiem, no kuriem 66,7% dalībnieku ir sievietes, 33,3% ir vīrieši. Respondenti elektroniskā veidā aizpildīja Humora stilu aptauju, kas mēra četrus humora stilus (biedrisko, pašuzmundrinošo, agresīvo un sevi noliedzošo), Apmierinātības ar dzīvi skalu, kas norāda uz to, cik cilvēks jūtas labi saistībā ar savu dzīvi, un BENCOR – aptauju, kas mēra labvēlīgo un korektīvo humora stilu. Pēc datu statistiskās analīzes, kura tika veikta SPSS datorprogrammā, apstiprinājās trīs no četrām hipotēzēm, kā arī tika gūtas atbildes uz diviem izvirzītajiem pētījuma jautājumiem.The aim of this study was to investigate whether and how the life satisfaction relates to different styles of humor. The study included 423 respondents, 16-72 years old, of which 66.7% are women, 33.3% are men. Respondents electronically filled in Humor Styles Questionnaire that measures four humor styles (affiliative, self-enhancing, aggressive, self-defeating), Satisfaction With Life Scale that measures the level of individuals life satisfaction and also BENCOR questionnaire that measures benevolent and corrective humor styles. According to data of statistical analysis, it confirmed three of the four hypotheses; also both of the research questions were answered

Bio-inspired Nanowire Arrays as Artificial Photoreceptors for Retinal Prosthesis

PURPOSE: The restoration of light response with complex spatiotemporal features in retinal degenerative diseases towards retinal prosthesis has proven to be a considerable challenge over the past decades. The state-of-art retinal prosthesis utilizes photodiode arrays fabricated on solid substrates, which does not have a complete tiling of the retinal tissue. Polymer based optoelectronic interface to retinal tissue, despite being compatible with flexible substrates, has limited spatial resolution for vision. Herein, inspired by the structure and function of photoreceptors in retinas, we developed bio-inspired artificial photoreceptors, i.e. gold nanoparticle-decorated titania (Au-TiO2) nanowire arrays, for restoration of multi-color visual responses in the retina of blind mice with degenerated photoreceptors. METHODS: single-cell intracellular measurements by patch-clamps, functional calcium imaging, in vivo electrophysiological recording, Pupillary light reflex. RESULTS: When Au-TiO2 nanowire arrays were in direct contact with blind mice retina, single-cell intracellular measurements by patch-clamps in the retinal ganglion cells (RGCs) revealed that green, blue and UV light responses were restored with a spatial resolution approaching or exceeding 100 &micro;m. Light responses in RGCs can be blocked by glutamatergic antagonists, indicating that nanowire array-interfaced retinas were capable of processing visual information through innate retinal circuits. Moreover, cellular-level population responses using functional calcium imaging in the Au-TiO2 nanowire array-interfaced blind retinas indicated that the receptive field is within the range of 200 &micro;m. Neurons in the primary visual cortex responded to light in vivo after subretinal implant of the nanowire arrays into the blind mice. The blind mice had lost a part of ability of the pupillary light reflex. But after subretinal implant of NW array, the blind mice regained the ability of pupillary light reflex. CONCLUSIONS: This study is among the first to show bio-inspired artificial photoreceptors and will shed light on the development of a new generation of optoelectronic toolkits for photo-coded subretinal implants and prosthetic devices.</p