Transcriptomic and proteomic insights into innate immunity and adaptations to a symbiotic lifestyle in the gutless marine worm Olavius algarvensis

Background: The gutless marine worm Olavius algarvensis has a completely reduced digestive and excretory system, and lives in an obligate nutritional symbiosis with bacterial symbionts. While considerable knowledge has been gained of the symbionts, the host has remained largely unstudied. Here, we generated transcriptomes and proteomes of O. algarvensis to better understand how this annelid worm gains nutrition from its symbionts, how it adapted physiologically to a symbiotic lifestyle, and how its innate immune system recognizes and responds to its symbiotic microbiota. Results: Key adaptations to the symbiosis include (i) the expression of gut-specific digestive enzymes despite the absence of a gut, most likely for the digestion of symbionts in the host's epidermal cells; (ii) a modified hemoglobin that may bind hydrogen sulfide produced by two of the worm's symbionts; and (iii) the expression of a very abundant protein for oxygen storage, hemerythrin, that could provide oxygen to the symbionts and the host under anoxic conditions. Additionally, we identified a large repertoire of proteins involved in interactions between the worm's innate immune system and its symbiotic microbiota, such as peptidoglycan recognition proteins, lectins, fibrinogen-related proteins, Toll and scavenger receptors, and antimicrobial proteins. Conclusions: We show how this worm, over the course of evolutionary time, has modified widely-used proteins and changed their expression patterns in adaptation to its symbiotic lifestyle and describe expressed components of the innate immune system in a marine oligochaete. Our results provide further support for the recent realization that animals have evolved within the context of their associations with microbes and that their adaptive responses to symbiotic microbiota have led to biological innovations

Understanding an empirically optimized contact

The electronic structure of the interface between the boron-doped oxygenated amorphous silicon “window layer” (a-SiOx:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon (μc- Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (−2.87 ± 0.27) eV and (−3.37 ± 0.27) eV, respectively. A lower tunnel junction barrier height at the μc-Si:H(B)/ZnO:Al interface compared to that at the a-SiOx:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a μc-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed

Start-up success of freelancers New microeconometric evidence from the German Socio-Economic Panel

If certain start-up characteristics will indicate a business success, knowing such characteristics could generate more successful start-ups and more efficient start-up counseling. Our study will contribut e to this by quantifying individual success determinants of freelance start-ups. The data base for the microeconometric analyses of the survival of the first three years is a revised German Socio-Economic Panel (SOEP) for 1992 until 2002, which allows to incorporate institutional, personal and family/household socio-economic variables. We describe and discuss the datawork to achieve compatible information over time within a revised GSOEP and present microeconometric rare events logit, logit and probit results. The start-up success measured as the probability to survive the first three years is first of all influenced by an active labour force participation with its acquired skills and working experiences just before the start-up period (rank 1), followed by a non-university degree as the highest general human capital indicator (rank 2), a general (non-linear) experience indicated by age (rank 3) and the business related background (rank 4) as the type of liberal profession in the group of the liberal medical professions and the liberal technical and scientific professions

Oligonucleotide-directed construction of mutations: a gapped duplex DNA procedure without enzymatic reactions in vitro.

The gapped duplex DNA approach to oligonucleotide-directed construction of mutations (Kramer et al. 1984, Nucl. Acids Res. 12, 9441-9456) has been developed further. A procedure is described that makes in vitro DNA polymerase/DNA ligase reactions dispensable. Direct transfection of host bacteria with gdDNA molecules of recombinant phage M13 plus mutagenic oligonucleotide results in marker yields in excess of 50% (gap size 1640 nucleotides). An important feature incorporated into the mutagenic oligonucleotide is the presence of one or two internucleotidic phosphorothioate linkages immediately adjacent to the 5'-terminus. Automated preparation and biochemical properties of such compounds are described as well as their performance in oligonucleotide-directed mutagenesis. A systematic study of the following parameters influencing marker yield is reported: Gap size, length of oligonucleotide, chemical nature of oligonucleotide termini and heatshock temperature during transformation