Osiris17 is indispensable for morphogenesis of intestinal tract in Locusta migratoria.

The Osiris gene family is believed to play important roles in insect biology. Previous studies mainly focused on the roles of Osiris in Drorophila, how Osiris operates during the development of other species remains largely unknown. Here, we investigated the role of LmOsi17 in development of the hemimetabolous insect Locusta migratoria. LmOsi17 was highly expressed in the intestinal tract of nymphs. Knockdown of LmOsi17 by RNA interference (RNAi) in nymphs resulted in growth defects. The dsLmOsi17-injected nymphs did not increase in body weight or size and eventually died. Immunohistochemical analysis showed that LmOsi17 was localized to the epithelial cells of the foregut and the gastric caecum. Histological observation and hematoxylin-eosin staining indicate that the foregut and gastric caecum are deformed in dsLmOsi17 treated nymphs, suggesting that LmOsi17 is involved in morphogenesis of foregut and gastric caecum. In addition, we observed a significant reduction in the thickness of the new cuticle in dsLmOsi17-injected nymphs compared to control nymphs. Taken together, these results suggest that LmOsi17 contributes to morphogenesis of intestinal tract that affects growth and development of nymphs in locusts.

Cell lineage analysis reveals signal tracing and compartment characterisation in Drosophila haltere.

Insect halteres, as specialised hind wings, play an important role during aerial manoeuvres. In Drosophila, halteres and wings are homologous appendages with different morphology. Previous studies have focused on the metamorphosis of halteres, while current knowledge about its cell lineage and regional compartmentalization is still limited. In this study, we performed cell-lineage tracing of canonical landmark signals in halteres and present a simple model for haltere development. Cell lineage tracing in wings was used as a reference. The nub showed wing-like expressions in halteres, whereas hth and pnr exhibited different expressions in adult wings and halteres. The lineage tracing revealed that the pouch region gives rise to end-bulb, and hinge cells contribute to proximal haltere formation. Moreover, we demonstrated that twi-expressing cells participate in the cell population of the distal end-bulb. Haematoxylin and eosin staining indicated that muscle cells were present at the distal end-bulb. These results indicated that adult halteres displayed unique cell lineage patterns and the muscle cells are important components of end-bulbs.

Osiris17 is essential for stable integrin localization and function during insect wing epithelia remodeling.

The dynamic adhesion between cells and their extracellular matrix is essential for the development and function of organs. During insect wing development, two epithelial sheets contact each other at their basal sites through the interaction of ßPS integrins with the extracellular matrix. We report that Osiris17 contributes to the maintenance of ßPS integrins localization and function in developing wing of Drosophila and locust. In flies with reduced Osiris17 expression the epithelia sheets fail to maintain the integrity of basal cytoplasmic junctional bridges and basal adhesion. In contrast to the continuous basal integrin localization in control wings, this localization is disrupted during late stages of wing development in Osiris17 depleted flies. In addition, the subcellular localization revealed that Osiris17 co-localizes with the endosomal markers Rab5 and Rab11. This observation suggests an involvement of Osiris17 in endosomal recycling of integrins. Indeed, Osiris17 depletion reduced the numbers of Rab5 and Rab11 positive endosomes. Moreover, overexpression of Osiris17 increased co-localization of Rab5 and ßPS integrins and partially rescued the detachment phenotype in flies with reduced ßPS integrins. Taken together, our data suggest that Osiris17 is an endosome related protein that contributes to epithelial remodeling and morphogenesis by assisting basal integrins localization in insects.

[Soil bacterial community composition and functional potentials along the vertical vegetation transect on Mount Segrila, Tibet, China]. / 西藏色季拉山垂直植被带土壤细菌群落组成及功能潜势.

Information on the spatial distribution of soil microbial communities on the Tibetan Pla-teau is critical for in-depth understanding the important roles of microbes in typical alpine ecosystems. In this study, 16S rDNA Illumina Miseq sequencing was used to analyze the variations in bacterial community composition and functional potentials in soils sampled from four elevations on Mount Segrila, Tibet, and the driving environmental factors. Results showed that richness and Shannon diversity index of soil bacteria significantly decreased with increasing altitude. The relative abundances of Acidobacteria, Chloroflexi, Gemmatimonadetes, and Nitrospirae significantly increased, whereas that of Proteobacteria, Actinobacteria and Bacteroidetes significantly decreased with increasing altitude. In KEGG pathway (level Ⅱ), the relative abundance of genes related to membrane transport and the metabolism of amino acids, lipids, terpenoids and polyketones was significantly lower at high elevations. In contrast, genes related to carbohydrates metabolism, signal transduction, replication and repair and enzyme family were more abundant at high altitudes. Soil bacterial community composition and predicted functions were significantly affected by vegetation types and soil properties, with soil pH being the key driver. There were significant correlations between the abundances of predicted functions and bacterial taxa, such as Acitnobacteria, Bacteroidetes, and Fibrobacteres. The dissimilarity in the composition of KEGG pathway genes along the elevational gradient (ß-diversity) showed a significantly positive correlation with the dissimilarity in bacterial community structure, indicating that there was a strong relationship between microbial community composition and potential functionality.

Determination of activity of denitrifying enzyme in soil samples by a headspace gas chromatographic technique.

This paper reported a headspace gas chromatography (HS-GC) for the determination of denitrifying enzyme activity in soil samples. It was based on measuring the NO2 signal in a set of closed/air-free vials containing soil samples that incubated at the designated conditions. The results showed that the method has a good measurement precision (RSD < 5.0%) and reasonable accuracy for determining the denitrifying enzyme activity in soil samples. It is simple and efficient, and very suitable to be used in batch sample analysis.

Chitinase 10 controls chitin amounts and organization in the wing cuticle of Drosophila.

Wings are essential for insect fitness. A number of proteins and enzymes have been identified to be involved in wing terminal differentiation, which is characterized by the formation of the wing cuticle. Here, we addressed the question whether chitinase 10 (Cht10) may play an important role in chitin organization in the wings of the fruit fly Drosophila melanogaster. Initially, we first found that Cht10 expression coincides with the expression of the chitin synthase coding gene kkv. This suggests that the respective proteins may cooperate during wing differentiation. In tissue-specific RNA interference experiments, we demonstrate that suppression of Cht10 causes an excess in chitin amounts in the wing cuticle. Chitin organization is severely disrupted in these wings. Based on these data, we hypothesize that Cht10 restricts chitin amounts produced by Kkv in order to ensure normal chitin organization and wing cuticle formation. In addition, we found by scanning electron microscopy that Cht10 suppression also affects the cuticle surface. In turn, cuticle inward permeability is enhanced in Cht10-less wings. Moreover, flies with reduced Cht10 function are unable to fly. In conclusion, Cht10 is essential for wing terminal differentiation and function.

Flexible manipulation of Omb levels in the endogenous expression region of Drosophila wing by combinational overexpression and suppression strategy.

Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments. The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model organisms. Driven by a given tissue-specific Gal4, expressing UAS-transgene or UAS-RNAi (RNA interference) could be used to up- or down-regulate target gene expression, respectively. However, the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic stock. Here, we describe a simple way to modulate optomotor blind (omb) expression levels in its endogenous expression region of the wing disc. We co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing pouch. The repression effect is more sensitive to temperature than that of overexpression. At low temperature, overexpression plays a dominant role but the efficiency is attenuated by UAS-omb-RNAi. In contrast, at high temperature RNAi predominates in gene expression regulation. By this strategy, we could manipulate omb expression levels at a moderate level. It allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.

Coupling between plant nitrogen and phosphorus along water and heat gradients in alpine grassland.

The biogeochemical cycles of plant nitrogen (N) and phosphorus (P) are interlinked by ecological processes, and the N and P cycles become uncoupled in response to global change experiments. However, the complex natural hydrothermal conditions in arid, semiarid and humid grassland ecosystems may have different effects on the availability of soil nutrients and moisture and may induce different balances between the N and P cycles. Here, we evaluated how the aridity index (AI) affects the balance between N and P of alpine grassland by the collected 115 sites along water and heat availability gradients on the Tibetan Plateau. We found that AI was negatively related to the variation in the coefficients of soil total dissolved N (TDN) and soil availability of P (SAP), and positive effects of AI, TDN and SAP on the coupling of plant N and P were detected. Thus, AI was positively correlated with soil nutrients and moisture, which may favor the co-uptake of soil nutrients by plants, resulting in a small variation in plant N and P in humid environments. Conversely, in arid environments with temporally variable soil nutrients, the plants tend to be more flexible in their N:P stoichiometry. Generally, our findings suggest that plant N and P could be more strongly coupled in humid conditions than in arid environments across alpine grasslands, with potential decoupling of the N biogeochemical cycle from P in an arid environment with an asynchronous dynamic of temperature and precipitation.

[Spatial pattern and evolutionary trend of sustainable development index of crop-livestock system: A case study in Shandong Province, China.] / ç§å »ç³»ç»Ÿå¯æŒç»­å‘å±•æŒ‡æ•°çš„ç©ºé—´æ ¼å±€åŠå ¶æ¼”å˜è¶‹åŠ¿­­ä»¥å±±ä¸œçœä¸ºä¾‹.

The intensification and industrialization of agricultural production leads to more and more serious separation of crop and livestock, which causes serious contradiction between livestock excrement and environment, and major challenges for agricultural sustainable development. Here, we quantitatively investigated the spatial pattern and evolutionary trend of the sustainable development index (ESI) of the crop-livestock system using the emergy analysis and the input/output data in Shandong Province (1999-2015). The results showed that the sustainability of the crop-livestock system in Shandong Province decreased from 1999 to 2015 by 22.0%. The net emergy yield ratio (EYR), environmental load ratio (ELR), and the benefits of unit economic inputs significantly increased. The environmental pressure from the crop and livestock production increased obviously, which was closely related to the increase of industrial resources input including electricity, compound fertilizer, and agricultural machinery. There were differences in the sustainable development level of the crop-livestock system among administrative prefectures in Shandong Province. The ESI level of crop-livestock system in most regions was relatively high, while that in the coastal regions (e.g., Weihai, Yantai) and industrial region (e.g., Zibo) was relatively low. The trends of the sustainable development of crop-livestock system varied in different cities. The sustainability of central and southern Shandong was decreasing, while that of northern Shandong was increasing year by year. In 2015, the ESI of the expected crop-livestock system (100% livestock manure replaced fertilizer) could reach 8.4, which was 2.6 times of that of the current crop-livestock system (30% livestock manure replaced fertilizer).