Project description:The dry season is a major challenge for Plasmodium falciparum parasites in many malaria endemic regions, where water availability limits mosquitoes to only part of the year. How P. falciparum bridges two transmission seasons months apart, without being cleared by the host or compromising host survival is poorly understood. Here we show that low levels of P. falciparum parasites persist in the blood of asymptomatic Malian individuals during the 5- to 6-month dry season, rarely causing symptoms and minimally affecting the host immune response. Parasites isolated during the dry season are transcriptionally distinct from those of subjects with febrile malaria in the transmission season, reflecting longer circulation within each replicative cycle, of parasitized erythrocytes without adhering to the vascular endothelium. Low parasite levels during the dry season are not due to impaired replication, but rather increased efficiency of splenic clearance of longer-circulating infected erythrocytes. We propose that P. falciparum virulence in areas of seasonal malaria transmission is regulated so that the parasite decreases its endothelial binding capacity, allowing increased splenic clearance and enabling several months of subclinical parasite persistence.
Project description:The identification of significantly differently expressed miRNAs expanded the repertoire of sheep miRNAs and could contribute to further studies on the molecular mechanism of estrous sheep in the non-breeding season under the different levels of nutrition.
Project description:Wood in conifers is mainly composed of tracheids. Some taxa, such as Pinus, present tracheids also in the rays, but are axial tracheids which constitute the vast majority of secondary xylem. Nevertheless, radial and axial parenchyma surrounding constitutive and traumatic resin ducts is known to serve as crucial reserve storage. These reserves are mobilized in response to traumatism, insect and pathogen attacks and defoliation, allowing the synthesis of resin, healing and, in few taxa, even resprouting. However, due to the low proportion of parenchymatic cells in secondary xylem relevant genes involved in their differentiation may have been missed in studies of transcriptomics of conifer wood formation. In this study we have used Pinus canariensis as a model species, given its comparatively high proportion of axial parenchyma. We have prepared two normalized libraries from its cambial zone, covering early- and late-wood differentiation. We have de novo assembled a transcriptome, and have analyzed the transcriptional profiles during the growing season, getting a more complete picture of wood formation in conifers. SUBMITTER_CITATION: Chano, V., López de Heredia, U., Collada, C., et al. (2017). Transcriptomic analysis of juvenile wood formation during the growing season in Pinus canariensis. Holzforschung, 0(0), pp. -. Retrieved 8 Aug. 2017, from doi:10.1515/hf-2017-0014
Project description:With the growing scale of largemouth bass breeding, the demand for seedlings is increasing. As global temperatures rise, it is crucial to study the effects of high temperature their regulatory mechanisms in largemouth bass. In this study, we simulated a high water temperature (28 ℃) in the non-breeding season in aquaculture ponds for 28 days to examine the growth, reproduction, metabolism, apoptosis, and methylation markers in largemouth bass; transcriptome analysis was also performed. The results showed no significant difference in body weight between male and female largemouth bass. However, the high-temperature exposed females had reduced growth hormone (GH) and estradiol (E2) levels and elevated cortisol levels. They also showed upregulated expression of AR, cyp19a, igf, fshβ, and lhβ in ovarian tissue. Transcriptomic comparisons between temperature treatments revealed 963 differentially expressed genes in females and 700 in males. Both the ECM receptor interaction and PPAR signaling pathways were significantly enriched. High-temperature enhanced the lipid metabolism process through the PPAR signaling pathway. High temperatures increased oxidative stress in females, which corresponded with increases in SOD, CAT, and GSH-Px, likely to counteract the excess reactive oxygen species. Moreover, endoplasmic reticulum stress was activated, indicated by increases in IRE1 and ATF6, leading to the upregulation of apoptosis-related genes and ovarian cell apoptosis. At high temperature, 5-MC%, demethylase, and methyltransferase were not different in females, while 5-MC% and methyltransferase were higher and demethylase was lower in males. In summary, sustained high temperature affected ovarian development by altering the expression of hormone and gonad related genes and inducing endoplasmic reticulum stress leading to ovarian cell apoptosis. However, low demethylase activity and high genome-wide methylation in the testis suggested that high temperatures may affect testis development via methylation, potentially impacting offspring production.
Project description:Transcriptional profiling of sweet corn plant density (crowding stress) tolerance influencing yield. Tolerance to crowding stress has played a crucial role in improving agronomic productivity in field corn; however, commercial sweet corn hybrids vary greatly in crowding stress tolerance. The experiment was conducted to 1) explore transcriptional changes among sweet corn hybrids with differential yield under crowding stress, 2) identify relationships between phenotypic responses and gene expression patterns, and 3) identify groups of genes associated with yield and crowding stress tolerance. Under conditions of crowding stress, three high-yielding and three low-yielding sweet corn hybrids were grouped for transcriptional and phenotypic analyses. Transcriptional analyses identified from 372 to 859 common differentially expressed genes (DEGs) for each hybrid. Large gene expression pattern variation among hybrids and only 26 common DEGs across all hybrid comparisons were identified, suggesting each hybrid has a unique response to crowding stress. Over-represented biological functions of DEGs also differed among hybrids. Strong correlation was observed between: 1) modules with up-regulation in high-yielding hybrids and yield traits, and 2) modules with up-regulation in low-yielding hybrids and plant/ear traits. Modules linked with yield traits may be important crowding stress response mechanisms influencing crop yield. Functional analysis of the modules and common DEGs identified candidate crowding stress tolerant processes in photosynthesis, glycolysis, cell wall, carbohydrate/nitrogen metabolic process, chromatin, and transcription regulation. Moreover, these biological functions were greatly inter-connected, indicating the importance of improving the mechanisms as a network. 3 high-and 3 low-yielding hybrids with 2-3 biological replications grown under high population density (crowding stress)