Current developments in embryo transfer

Chapter 32. Applications of Recombinant DNA Technology of Interest to Medicinal Chemists

Embryo transfer has added a new dimension to animal reproduction and breeding. It is now possible to obtain up to 40 offspring from a selected female in 1 yr. Originally all transfers were done surgically; however, recently, non-surgical embryo recovery has been highly successful. Future developments are required for equal success in non-surgical implantation. The problems in embryo transfer rest with unreliable superovulation, fertilization, embryo and recipient identification. Pregnant mare serum gonadotrophin has shown considerable variation as a superovulating agent when administered to embryo transfer donors with the use of prostaglandin F2α as a leuteolytic agent. Sources of variation in donor and recipient females are discussed, including egg quality, timing of transfer and the use of surgical and non-surgical transfer procedures. With the use of optimal conditions it should be possible to obtain an average of approximately eight pregnancies per successful donor. The role of embryo transfer in beef, dual purpose and dairy improvement programs is discussed. Embryo transfer is currently being used for the expansion of limited gene pools whereas in the future such transfers will be for the successful proliferation of offspring from the mating of genetically superior dams and sires. A doubling of response can be obtained in beef improvement programs where defined objectives can be identified.

Chapter 13 - Evolution and Genetic Engineering

Chapter Thirteen - Role of biotechnology on animal breeding and genetic improvement

Editorials1 July 1981On Reporting Interferon ResearchSIDNEY E. GROSSBERG, M.D.SIDNEY E. GROSSBERG, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-95-1-115 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptRecent progress in interferon research has emphasized the importance of the use of interferon standard preparations and the proper reporting of results of interferon studies. With the availability of sufficient quantities of human interferons for clinical trials, the preparations have been shown effective in the treatment of hepatitis B, respiratory virus infections, varicella-zoster, and other herpesvirus infections and of certain human tumors. Findings of these trials and of the many ongoing experimental investigations underscore the need for accurate comparisons among laboratories of the materials studied and the results obtained. Such studies include application of recombinant DNA technology to produce numerous...

This book, edited by Professor Hiroo Imura of Kyoto (Japan) University, is a well-organized review of several basic and clinical aspects of normal and abnormal functions of the pituitary gland. Approximately two thirds of this volume contain chapters that present the most current information on the morphology, regulation of secretory activity, and molecular biology of the anterior and the posterior lobes of the pituitary gland. A section on gene organization and the biosynthesis and chemistry of the eight pituitary hormones of anterior and posterior lobe origin documents the remarkable advances made by the application of recombinant DNA technology to our understanding of hormone precursors, their processing to biologically active molecules, and some of the factors that regulate the genetic expression of these processes. A second section contains five chapters that provide particularly comprehensive reviews of the physiologic mechanisms that regulate the secretion of the pituitary hormones. A final section deals with the

Messenger RNA isolated from chicken pituitaries was used to construct a chicken pituitary cDNA library. A chicken growth hormone cDNA clone was isolated using 32P-labeled mammalian growth hormone cDNA probes. The amino acid sequence (derived from the DNA sequence) of the mature form of chicken growth hormone shows 77% homology with that of bovine growth hormone. The chicken growth hormone cDNA clone was used to generate a vector capable of producing chicken growth hormone in Escherichia coli. The recombinant E. coli-derived chicken growth hormone was similar to pituitary chicken growth hormone in several biochemical and immunological properties. The recombinant-derived hormone has been used to establish a sensitive radioimmunoassay for growth hormone determinations made from chicken sera. The chicken growth hormone gene has also been introduced into a retroviral vector capable of establishing productive infections of chicken cells both in in vitro and in vivo. The resulting infections are accompanied by the production of radioimmunoassay-detectable growth hormone. The concentrations of growth hormone in sera of Leghorn chickens infected with the recombinant retrovirus are three- to tenfold higher than in control animals.

Acetylcholinesterase: Converting a vulnerable target to a template for antidotes and detection of inhibitor exposure

We present here the first report of a transformation system developed for the filamentous, ML-236B (compactin)-producing fungus Penicillium citrinum. Hygromycin B-resistant colonies were obtained after treatment of protoplasts with a vector containing an Escherichia coli hygromycin B phosphotransferase gene fused to a 3-phosphoglycerate kinase promoter from Aspergillus nidulans. The transformation rate was 194 transformants per microgram circular DNA per 4 x 10(5) viable protoplasts under optimized transformation conditions. Transformation took place via the integration of plasmid DNA into the fungal chromosomal DNA. Most of the integration events appeared to produce tandemly iterated arrays of plasmid molecules at different sites in the chromosome. The transformed, drug-resistant, phenotype and the integrated plasmids were mitotically stable with or without selection in a majority of cases. The demonstration of such a transformation system is an essential first step in the application of recombinant DNA technology to strain improvement and for the production of novel ML-236B derivatives.

Hepatitis B surface antigen in the form of 22 nm spherical particles (and tubular forms) is excess virus coat protein. Guidelines for the preparation of the 22 nm spherical particles (and their separated polypeptides) derived from the plasma of asymptomatic human carriers, were suggested by the WHO Expert Committee on Viral Hepatitis in 1977, and the proposed requirements for the 22 nm hepatitis B particle vaccine were published by the WHO Expert Committee on Biological Standardisation in 1981 and revised in 1983. Such preparations have been tested for safety and protective efficacy and many clinical trials with the plasma-derived vaccine have demonstrated the immunogenicity, high protective efficacy and safety of the currently licensed preparations. Polypeptide vaccines, derived from the surface antigen from any source, have several advantages which include precise biochemical characterisation, exclusion of genetic material of viral origin, exclusion of host or donor-derived substances and enhanced potency. A polypeptide vaccine in micellar form has been developed in London. The applications of recombinant DNA technology permit the isolation, purification and selective amplification of almost any individual segment of DNA from practically any organism in convenient biological systems such as bacteria, yeast, or any other cell including mammalian cells. Considerable progress has been made with vaccines prepared from antigen expressed in yeast (Saccharomyces cerevisiae). Cloning of the DNA of hepatitis B virus has resulted in sequencing of nucleotides and mapping of the amino acids of antigens. Information obtained from the sequencing of the 226 amino acids of hepatitis B surface antigen has led to the development of chemically synthesised peptides corresponding to amino acid sequences predicted from the nucleotide map. Several such synthetic peptides, when linked to potent adjuvants elicit antibodies in experimental animals which react with the surface antigen. The potential of pure chemically synthetic vaccines against hepatitis B, and other infectious agents, is under intensive investigation since such vaccines should be chemically well-defined, uniform, safe and cheap to produce. Studies have been carried out recently using a chemically synthetic peptide in a linear and in a cyclical form corresponding to the amino acids sequence 139-147 of the major polypeptide I of hepatitis B surface antigen. The synthetic antigens and the native polypeptide complex p23-gp28 purified from hepatitis B surface antigen in plasma were used for the measurement of affinity of the antibody to the surface antigen (anti-HBs) in human sera.(ABSTRACT TRUNCATED AT 400 WORDS)

The application of recombinant DNA technology in the lens crystallin field has resulted in significant advances and promises to yield important information regarding the mechanism of cataractogenesis.

Early on, crystallography was a domain of mineralogy and mathematics and dealt mostly with symmetry properties and imaginary crystal lattices. This changed when Wilhelm Conrad Röntgen discovered X-rays in 1895, and in 1912, Max von Laue and his associates discovered that X-ray irradiated salt crystals would produce diffraction patterns that could reveal the internal atomic periodicity of the crystals. In the same year, the father-and-son team, Henry and Lawrence Bragg successfully solved the first crystal structure of sodium chloride and the era of modern crystallography began. Protein crystallography (PX) started some 20 years later with the pioneering work of British crystallographers. In the past 50–60 years, the achievements of modern crystallography and particularly those in PX have been due to breakthroughs in theoretical and technical advancements such as phasing and direct methods; to more powerful X-ray sources such as synchrotron radiation; to more sensitive and efficient X-ray detectors; to ever faster computers and to improvements in software. The exponential development of PX has been accelerated by the invention and applications of recombinant DNA technology that can yield nearly any protein of interest in large amounts and with relative ease. Novel methods, informatics platforms and technologies for automation and high-throughput have allowed the development of large-scale, high-efficiency macromolecular crystallography efforts in the field of structural genomics. Very recently, the X-ray free-electron laser sources and its applications in PX have shown great potential for revolutionizing the whole field again in the near future.

The ability to regenerate plants from poplar cells cultured in vitro suggests that poplars may prove a valuable model system for the application of recombinant DNA technology to deciduous trees. We report here the transformation of a hybrid Populus trichocarpa × deltoides with two strains of Agrobacterium tumefaciens, as demonstrated by phytohormone autonomous growth, opine production, and Southern blot analysis.

Foot-and-mouth disease virus

Background: Snakebite envenomation remains a critical public health concern in India, with its substantialmorbidity and mortality burden. Addressing this issue is imperative, as snakebite-related deaths are preventableand yet disproportionately affect vulnerable populations in rural India.Materials and Methods: This autopsy-based study aimed to assess the prevalence and characteristics of lethalsnakebite cases in the Guntur region, Andhra Pradesh by considering case data, autopsy findings and ancillaryinvestigation findings. Additionally, an attempt was made to recommend preventive measures and raise awarenessamong the local population regarding snakebite prevention.Results: Snakebite incidents were more common among males who belonged to the agricultural workforce. Thesebites predominantly occurred during the rainy season and during daylight hours. The majority of victims werefrom rural areas, and the incidence was higher among younger individuals. Most of the bites were localized onthe lower extremities. Additionally, a significant number of victims experienced fatal outcomes within six hoursof envenomation.Conclusion: Snakebite is a highly neglected tropical disease but a preventable one. The Indian government is givingpriority to snakebite venomics, proteomics, and the application of recombinant DNA technology for developingantivenoms, diverging from conventional animal-derived sources. Given the wide-ranging biogeographicdistribution of venom type in venomous snakes, a re-evaluation of the ‘big four’ strategy is being advocated,promoting alternative methods for effective antivenom production.