昆虫抗药性与适合度

昆虫抗药性的产生常伴有适合度劣势(即适合度代价),即抗性个体常表现出发育速率较慢、存活率和生殖力较低。文章主要阐述害虫抗药性与生物适合度和适合度代价的关系以及适合度代价产生的机制、特性及影响因素。并从生态学角度论述害虫抗药性的进化,为探索抗性发展规律及害虫抗性治理提供理论依据。     

Oestrone Sulphate Measurements for the Prediction of Small or Large Litters in Pigs

Serum from 88 pregnant sows and gilts was sampled 24 and 28 days after their first insemination or mating day. The oestrone sulphate (E1S) concentration in the samples was assessed with a commercially available radioimmunoassay kit modified for use with swine serum. The first aim was to test whether it was possible to predict litters of total number <10 piglets at term. The second aim was to compare the use of day 24 or day 28 samples, or of both, in this prediction.     

Computer-assisted re-design of spectrin SH3 residue clusters

We have developed a protein design computer program, called Perla, which performs searches in sequence space to uncover optimal amino acid sequences for desired protein three-dimensional structures. Optimal sequences are localised at the minima of a sequence-structure energy landscape defined using a complex scoring function (an all-atom molecular mechanics force field plus statistical terms including entropy and solvation) measured with respect to a reference state simulating a denatured protein. Sequence choices eventually optimise side chain packing, secondary structure propensities, and hydrogen bonding and electrostatics interactions. Perla was used to re-design clusters of residues of the SH3 domain of alpha-spectrin. Several mutant proteins were produced and characterised. Some of our designed proteins have significantly higher stabilities (stability enhancements about 0.25, 0.70 and 1.0 kcal mol(-1)) than the wild-type protein. These successful protein re-designs, and similar examples found in the literature, establish the quality of the structure-based computational approach to protein design.     

Regulation of Cre recombinase activity by the synthetic steroid RU 486.

To create a strategy for inducible gene targeting we developed a Cre-lox recombination system which responds to the synthetic steroid RU 486. Several fusions between Cre recombinase and the hormone binding domain (HBD) of a mutated human progesterone receptor, which binds RU 486 but not progesterone, were constructed. When tested in transient expression assays recombination activities of all fusion proteins were responsive to RU 486, but not to the endogenous steroid progesterone. However, the observed induction of recombination activity by the synthetic steroid varied between the different fusion proteins. The fusion with the highest activity in the presence of RU 486 combined with low background activity in the absence of the steroid was tested after stable expression in fibroblast and embryonal stem (ES) cells. We could demonstrate that its recombination activity was highly dependent on RU 486. Since the RU 486 doses required to activate recombination were considerably lower than doses displaying anti-progesterone effects in mice, this system could be used as a valuable tool for inducible gene targeting.     

Survey of Genomics Approaches to Improve Bioenergy Traits in Maize,Sorghum and Sugarcane

Bioenergy crops currently provide the only source of alternative energy with the potential to reduce the use of fossil transportation fuels in a way that is compatible with existing engine technology,including in developing countries.Even though bioenergy research is currently receiving considerable attention,many of the concepts are not new,but rather build on intense research efforts from 30 years ago.A major difference with that era is the availability of genomics tools that have the potential to acceler...     

Transgenic mouse proteomics identifies new 14-3-3-associated proteins involved in cytoskeletal rearrangements and cell signaling

Identification of protein-protein interactions is crucial for unraveling cellular processes and biochemical mechanisms of signal transduction. Here we describe, for the first time, the application of the tandem affinity purification (TAP) and LC-MS method to the characterization of protein complexes from transgenic mice. The TAP strategy developed in transgenic mice allows the emplacement of complexes in their physiological environment in contact with proteins that might only be specifically expressed in certain tissues while simultaneously ensuring the right stoichiometry of the TAP protein versus their binding partners and represents a novelty in proteomics approaches used so far. Mouse lines expressing TAP-tagged 14-3-3zeta protein were generated, and protein interactions were determined. 14-3-3 proteins are general regulators of cell signaling and represent up to 1% of the total brain protein. This study allowed the identification of almost 40 novel 14-3-3zeta-binding proteins. Biochemical and functional characterization of some of these interactions revealed new mechanisms of action of 14-3-3zeta in several signaling pathways, such as glutamate receptor signaling via binding to homer homolog 3 (Homer 3) and in cytoskeletal rearrangements and spine morphogenesis by binding and regulating the activity of the signaling complex formed by G protein-coupled receptor kinase-interactor 1 (GIT1) and p21-activated kinase-interacting exchange factor beta (betaPIX).     

Analysis of the human HP1 interactome reveals novel binding partners

Heterochromatin protein 1 (HP1) has first been described in Drosophila as an essential component of constitutive heterochromatin required for stable epigenetic gene silencing. Less is known about the three mammalian HP1 isotypes CBX1, CBX3 and CBX5. Here, we applied a tandem affinity purification approach coupled with tandem mass spectrometry methodologies in order to identify interacting partners of the mammalian HP1 isotypes. Our analysis identified with high confidence about 30–40 proteins co-eluted with CBX1 and CBX3, and around 10 with CBX5 including a number of novel HP1-binding partners. Our data also suggest that HP1 family members are mainly associated with a single partner or within small protein complexes composed of limited numbers of components. Finally, we showed that slight binding preferences might exist between HP1 family members.