Transcriptome Analysis of the Chinese White Wax Scale Ericerus pela with Focus on Genes Involved in Wax Biosynthesis

BACKGROUND: The Chinese white wax scale, Ericerus pela Chavannes is economically significant for its role in wax production. This insect has been bred in China for over a thousand years. The wax secreted by the male scale insect during the second-instar larval stage has been widespread used in wax candle production, wax printing, engraving, Chinese medicine, and more recently in the chemical, pharmaceutical, food, and cosmetics industries. However, little is known about the mechanisms responsible for white wax biosynthesis. The characterization of its larval transcriptome may promote better understanding of wax biosynthesis. METHODOLOGY/PRINCIPAL FINDINGS: In this study, characterization of the transcriptome of E. pela during peak wax secretion was performed using Illumina sequencing technology. Illumina sequencing produced 41,839 unigenes. These unigenes were annotated by blastx alignment against the NCBI Non-Redundant (NR), Swiss-Prot, KEGG, and COG databases. A total of 104 unigenes related to white wax biosynthesis were identified, and 15 of them were selected for quantitative real-time PCR analysis. We evaluated the variations in gene expression across different development stages, including egg, first/second instar larvae, male pupae, and male and female adults. Then we identified five genes involved in white wax biosynthesis. These genes were expressed most strongly during the second-instar larval stage of male E. pela. CONCLUSION/SIGNIFICANCE: The transcriptome analysis of E. pela during peak wax secretion provided an overview of gene expression information at the transcriptional level and a resource for gene mining. Five genes related to white wax biosynthesis were identified

DLK1 Is a Somato-Dendritic Protein Expressed in Hypothalamic Arginine-Vasopressin and Oxytocin Neurons

Delta-Like 1 Homolog, Dlk1, is a paternally imprinted gene encoding a transmembrane protein involved in the differentiation of several cell types. After birth, Dlk1 expression decreases substantially in all tissues except endocrine glands. Dlk1 deletion in mice results in pre-natal and post-natal growth deficiency, mild obesity, facial abnormalities, and abnormal skeletal development, suggesting involvement of Dlk1 in perinatal survival, normal growth and homeostasis of fat deposition. A neuroendocrine function has also been suggested for DLK1 but never characterised. To evaluate the neuroendocrine function of DLK1, we first characterised Dlk1 expression in mouse hypothalamus and then studied post-natal variations of the hypothalamic expression. Western Blot analysis of adult mouse hypothalamus protein extracts showed that Dlk1 was expressed almost exclusively as a soluble protein produced by cleavage of the extracellular domain. Immunohistochemistry showed neuronal DLK1 expression in the suprachiasmatic (SCN), supraoptic (SON), paraventricular (PVN), arcuate (ARC), dorsomedial (DMN) and lateral hypothalamic (LH) nuclei. DLK1 was expressed in the dendrites and perikarya of arginine-vasopressin neurons in PVN, SCN and SON and in oxytocin neurons in PVN and SON. These findings suggest a role for DLK1 in the post-natal development of hypothalamic functions, most notably those regulated by the arginine-vasopressin and oxytocin systems

Exploring early steps in biofilm formation: set-up of an experimental system for molecular studies

Background: Bacterial biofilms are predominant in natural ecosystems and constitute a public health threat because of their outstanding resistance to antibacterial treatments and especially to antibiotics. To date, several systems have been developed to grow bacterial biofilms in order to study their phenotypes and the physiology of sessile cells. Although relevant, such systems permit analysis of various aspects of the biofilm state but often after several hours of bacterial growth.Results: Here we describe a simple and easy-to-use system for growing P. aeruginosa biofilm based on the medium adsorption onto glass wool fibers. This approach which promotes bacterial contact onto the support, makes it possible to obtain in a few minutes a large population of sessile bacteria. Using this growth system, we demonstrated the feasibility of exploring the early stages of biofilm formation by separating by electrophoresis proteins extracted directly from immobilized cells. Moreover, the involvement of protein synthesis in P. aeruginosa attachment is demonstrated.Conclusions: Our system provides sufficient sessile biomass to perform biochemical and proteomic analyses from the early incubation period, thus paving the way for the molecular analysis of the early stages of colonization that were inaccessible to date

Electrotransformation of Saccharomyces cerevisiae

Intact yeast cell transformation is easily achieved by gene electrotransfer (GET). The procedure is fast and efficient in terms of transformants/mu g DNA. Yeast cells in exponential growth phase are washed, treated for a short period with dithiothreitol (DTT) and then mixed with the plasmid DNA in a buffer with a low conductivity. A single well defined electric pulsed is delivered. After a 1 h incubation in the growth medium without selection, transformants are obtained on a selective plate medium. After a short description of the present knowledge on the events affecting the yeast cell as a consequence of the pulsed electric field, a step-by-step protocol is reported for Saccharomyces cerevisiae