Effective generation of transgenic pigs and mice by linker based sperm-mediated gene transfer.

BACKGROUND: Transgenic animals have become valuable tools for both research and applied purposes. The current method of gene transfer, microinjection, which is widely used in transgenic mouse production, has only had limited success in producing transgenic animals of larger or higher species. Here, we report a linker based sperm-mediated gene transfer method (LB-SMGT) that greatly improves the production efficiency of large transgenic animals. RESULTS: The linker protein, a monoclonal antibody (mAb C), is reactive to a surface antigen on sperm of all tested species including pig, mouse, chicken, cow, goat, sheep, and human. mAb C is a basic protein that binds to DNA through ionic interaction allowing exogenous DNA to be linked specifically to sperm. After fertilization of the egg, the DNA is shown to be successfully integrated into the genome of viable pig and mouse offspring with germ-line transfer to the F1 generation at a highly efficient rate: 37.5% of pigs and 33% of mice. The integration is demonstrated again by FISH analysis and F2 transmission in pigs. Furthermore, expression of the transgene is demonstrated in 61% (35/57) of transgenic pigs (F0 generation). CONCLUSIONS: Our data suggests that LB-SMGT could be used to generate transgenic animals efficiently in many different species

Identification of ejaculated proteins in the house mouse (Mus domesticus) via isotopic labeling

<p>Abstract</p> <p>Background</p> <p>Seminal fluid plays an important role in successful fertilization, but knowledge of the full suite of proteins transferred from males to females during copulation is incomplete. The list of ejaculated proteins remains particularly scant in one of the best-studied mammalian systems, the house mouse (<it>Mus domesticus</it>), where artificial ejaculation techniques have proven inadequate. Here we investigate an alternative method for identifying ejaculated proteins, by isotopically labeling females with ¹⁵N and then mating them to unlabeled, vasectomized males. Proteins were then isolated from mated females and identified using mass spectrometry. In addition to gaining insights into possible functions and fates of ejaculated proteins, our study serves as proof of concept that isotopic labeling is a powerful means to study reproductive proteins.</p> <p>Results</p> <p>We identified 69 male-derived proteins from the female reproductive tract following copulation. More than a third of all spectra detected mapped to just seven genes known to be structurally important in the formation of the copulatory plug, a hard coagulum that forms shortly after mating. Seminal fluid is significantly enriched for proteins that function in protection from oxidative stress and endopeptidase inhibition. Females, on the other hand, produce endopeptidases in response to mating. The 69 ejaculated proteins evolve significantly more rapidly than other proteins that we previously identified directly from dissection of the male reproductive tract.</p> <p>Conclusion</p> <p>Our study attempts to comprehensively identify the proteins transferred from males to females during mating, expanding the application of isotopic labeling to mammalian reproductive genomics. This technique opens the way to the targeted monitoring of the fate of ejaculated proteins as they incubate in the female reproductive tract.</p

Visible light TiO\u3csub\u3e2\u3c/sub\u3e photocatalysts assessment for air decontamination

\u3cp\u3eDifferent visible light responses of commercial TiO\u3csub\u3e2\u3c/sub\u3e photocatalysts are assessed for their application in air decontamination. To do that the modified TiO\u3csub\u3e2\u3c/sub\u3e catalysts were immobilized on borosilicate glass plates according to a dip coating method. Then, the photocatalytic performance of these plates was evaluated in a continuous gas flat plate photoreactor irradiated with visible light lamps using two representative air pollutants: nitrogen oxide and acetaldehyde. Working under visible light, the modified TiO\u3csub\u3e2\u3c/sub\u3e catalysts were compared by means of efficiency parameters: the true quantum efficiency, which relates the moles of degraded pollutant with the moles of the absorbed photons, and the apparent photonic efficiency, which relates the moles of degraded pollutant with the moles of incident photons. Also, the photocatalytic pollutants degradation by immobilized modified TiO\u3csub\u3e2\u3c/sub\u3e could be related with their optical properties, finding a clear correlation between them. These results are useful to decide which TiO\u3csub\u3e2\u3c/sub\u3e will be more efficient for a full scale air decontamination process under visible light illumination.\u3c/p\u3

Efficient photoinduced energy transfer mediated by aromatic homoconjugated bridges

A new donor bridge acceptor (D-B-A) dyad consisting of ruthenium(II) and iridium(III) species separated by an homoconjugated bridge derived from 7,7-diphenylnorbornane [Ir-Nor-Ru](3+) has been synthesised. The photophysical and electrochemical properties of the heterodinuclear complex have been compared with those of the analogous homodinuclear complexes [Ru-Nor-Ru](4+) and [Ir-Nor-Ir](2+). Transient absorption spectra on the nanosecond and sub-picosecond timescales show, for the first time, that an homoconjugated bridge can mediate efficiently in the photoinduced energy transfer from the iridium(III) to the ruthenium(II) centres according to a Dexter-type mechanism