The first transgenic fish was generated in China about 30 years ago. Since then, considerable progress has been achieved for farmed fishes breeding with improvement of target traits of growth, disease resistance, stress tolerance, and nutrition qualities. Up to now, the technology of transgenic fish breeding is almost mature and the biosafety assessment is established. In this review, a successful example of the fast-growing transgenic common carp was presented and the foreground of transgenic fish breeding was also discussed and prospected.
Animals ; Animals, Genetically Modified ; Breeding ; China ; Fishes

Objective: To evaluate the vascular toxicity of chemicals by a real-time observation approach using the transgenic zebrafish. Methods: The spatiotemporal vascular alterations of transgenic zebrafish after chemical exposure were assessed by laser confocal microscopy and high-content screening analysis, respectively. Results: The method using Laser Confocal Microscopy (LCM) is easier to operate and yields high-resolution images, while it is lower throughput and inefficient. In contrast, high-content analysis (HCA) analysis obtains high-quality data of vascular toxicity manifesting whole blood vasculature, whereas it requires delicate operation procedures and advanced experimental conditions. Conclusion: Two kinds of zebrafish imaging methods each have advantages and disadvantages. LCM is suitable for the evaluation of a small number of chemicals. HCA, a cutting-edge technology, has great potential for chemical safety assessment allowing high throughput vascular toxicity tests of a good number of chemicals at a time.
Animals ; Animals, Genetically Modified ; Cardiovascular System ; Toxicity Tests ; Zebrafish

Tumor is a neoplasm formed by the abnormal proliferation of local tissue cells under the effects of different tumorigenic factors. Tumor-therapy has always been a difficult clinical issue, while regular cancer treatments, such as radiotherapy, chemotherapy and surgery, have obvious limitations. Earlier studies have shown that some obligate anaerobes or facultative anaerobes have anti-tumor effects, for example, Salmonella typhymurium as facultative anaerobic bacteria can selectively colonize tumors and inhibit their growth. Besides, Salmonella has many advantages in tumor-therapy. In the past decade or two, many researchers have carried out genetic manipulation to attenuate the virulence of Salmonella, to improve their specificity of tumor colonization and specially to use attenuated Salmonella as carriers to deliver a variety of anti-tumor therapeutic molecules, and these genetically modified Salmonella have shown good anti-tumor effects in many animal experiments. Along with further research of Salmonella-mediated antitumor treatment, applications of genetically modified Salmonella for more effective tumor-therapy are promising. We reviewed the anti-tumor mechanisms of Salmonella, the research progress in tumor-therapy using genetically modified Salmonella, and current problems and possible solutions.
Animals ; Humans ; Microorganisms, Genetically-Modified ; Neoplasms ; therapy ; Salmonella ; genetics ; Virulence

At present, the research of biological living materials mainly focuses on applications in vitro, such as using a single bacterial strain to produce biofilm and water plastics. However, due to the small volume of a single strain, it is easy to escape when used in vivo, resulting in poor retention. In order to solve this problem, this study used the surface display system (Neae) of Escherichia coli to display SpyTag and SpyCatcher on the surface of two strains, respectively, and constructed a double bacteria "lock-key" type biological living material production system. Through this force, the two strains are cross-linked in situ to form a grid-like aggregate, which can stay in the intestinal tract for a longer time. The in vitro experiment results showed that the two strains would deposit after mixing for several minutes. In addition, confocal imaging and microfluidic platform results further proved the adhesion effect of the dual bacteria system in the flow state. Finally, in order to verify the feasibility of the dual bacteria system in vivo, mice were orally administrated by bacteria A (p15A-Neae-SpyTag/sfGFP) and bacteria B (p15A-Neae-SpyCatcher/mCherry) for three consecutive days, and then intestinal tissues were collected for frozen section staining. The in vivo results showed that the two bacteria system could be more detained in the intestinal tract of mice compared with the non-combined strains, which laid a foundation for further application of biological living materials in vivo.
Animals ; Mice ; Bacteria ; Microorganisms, Genetically-Modified ; Escherichia coli/genetics*

Genetically modified (GM) crops were first introduced to farmers in 1995 with the intent to provide better crop yield and meet the increasing demand for food and feed. GM crops have evolved to include a thorough safety evaluation for their use in human food and animal feed. Safety considerations begin at the level of DNA whereby the inserted GM DNA is evaluated for its content, position and stability once placed into the crop genome. The safety of the proteins coded by the inserted DNA and potential effects on the crop are considered, and the purpose is to ensure that the transgenic novel proteins are safe from a toxicity, allergy, and environmental perspective. In addition, the grain that provides the processed food or animal feed is also tested to evaluate its nutritional content and identify unintended effects to the plant composition when warranted. To provide a platform for the safety assessment, the GM crop is compared to non-GM comparators in what is typically referred to as composition equivalence testing. New technologies, such as mass spectrometry and well-designed antibody-based methods, allow better analytical measurements of crop composition, including endogenous allergens. Many of the analytical methods and their intended uses are based on regulatory guidance documents, some of which are outlined in globally recognized documents such as Codex Alimentarius. In certain cases, animal models are recommended by some regulatory agencies in specific countries, but there is typically no hypothesis or justification of their use in testing the safety of GM crops. The quality and standardization of testing methods can be supported, in some cases, by employing good laboratory practices (GLP) and is recognized in China as important to ensure quality data. Although the number of recommended, in some cases, required methods for safety testing are increasing in some regulatory agencies, it should be noted that GM crops registered to date have been shown to be comparable to their nontransgenic counterparts and safe . The crops upon which GM development are based are generally considered safe.
Agriculture ; Animal Feed ; Animals ; Biotechnology ; China ; Consumer Product Safety ; Food, Genetically Modified ; Humans ; Models, Animal ; Plants, Genetically Modified ; Safety

With the research and development of genetically engineered animals (GEAs) in breeding of new variety, xenotransplantation, bioreactor and disease model, biosafety issues of GEAs have attracted widespread attentions worldwide. So far, governments and agencies have established corresponding laws and regulations to regulate research and application of GEAs or their derived products. We reviewed research contents, evaluated principles, policies and procedures for biosafety of GEAs, also enumerated upcoming approved products of GEAs. Finally, we suggested perspectives of research and application of GEAs or their derived products.
Agriculture ; economics ; legislation & jurisprudence ; Animals ; Animals, Genetically Modified ; genetics ; growth & development ; Biotechnology ; economics ; legislation & jurisprudence ; Food Safety ; Food, Genetically Modified ; economics ; standards ; Laboratories ; standards

Spermatogonial transplantation (ST) is a novel technique which mechanism is similar to other transplantations. The donor testicular cells transferred into recipient testes by the microinjection can initiate spermatogenesis and produce sperm in the recipient testis. The homograft has got success. The xenograft in which (man, horse, bull or rat, can be the donor; immunodeficiency mouse can be the recipient) and cryopreserved germ cells can not clonize in the recipient testes. The reason may be immunoreaction. ST technique will be propitious to these fields, 1. to investigate fundamental aspects of spermatogenesis; 2. to regenerate spermatogenesis in infertile individuals; 3. to develop transgenic animals.
Animals ; Animals, Genetically Modified ; Humans ; Male ; Spermatogenesis ; physiology ; Spermatogonia ; transplantation ; Transplantation, Heterologous

The production of human recombinant proteins in milk of transgenic farm animals offers a safe, very cost-effective source of commercially important proteins that cannot be produced as efficiently in adequate quantities by other methods. This review has summarized the current status of gene selection, vector construct, transgenic methods, economics, and obvious potential in transgenic animals bioreactors. Recently, a more powerful approach was adopted in the transgenic animals founded on the application of nuclear transfer. As we will illustrate, this strategy presents a breakthrough in the overall efficiency of generating transgenic farm animals, product consistency, and time of product development. The successful adaptation of Cre-/lox P-mediated site-specific DNA recombination systems in farm animals will offer unprecedented possibilities for generating transgenic animals.
Animals ; Animals, Genetically Modified ; Bioreactors ; Breast ; metabolism ; Cell Transplantation ; Gene Expression ; Humans

Pigs are considered as ideal donors for xenotransplantation because they have many physiological and anatomical characteristics similar to human beings. However, antibody-mediated immunity, which includes both natural and induced antibody responses, is a major challenge for the success of pig-to-primate xenotransplantation. Various genetic modification methods help to tailor pigs to be appropriate donors for xenotransplantation. In this study, we applied transcription activator-like effector nuclease (TALEN) to knock out the porcine α-1, 3-galactosyltransferase gene GGTA1, which encodes Gal epitopes that induce hyperacute immune rejection in pig-to-human xenotransplantation. Meanwhile, human leukocyte antigen-G5 gene HLA-G5, which acts as an immunosuppressive factor, was co-transfected with TALEN into porcine fetal fibroblasts. The cell colonies of GGTA1 biallelic knockout with positive transgene for HLA-G5 were chosen as nuclear donors to generate genetic modified piglets through a single round of somatic cell nuclear transfer. As a result, we successfully obtained 20 modified piglets that were positive for GGTA1 knockout (GTKO) and half of them expressed the HLA-G5 protein. Gal epitopes on the cell membrane of GTKO/HLA-G5 piglets were completely absent. Western blotting and immunofluorescence showed that HLA-G5 was expressed in the modified piglets. Functionally, the fibroblasts from the GTKO/HLA-G5 piglets showed enhanced resistance to complement-mediated lysis ability compared with those from GTKO-only or wild-type pigs. These results indicate that the GTKO/HLA-G5 pigs could be a valuable donor model to facilitate laboratory studies and clinics for xenotransplantation.
Animals ; Animals, Genetically Modified ; Gene Knockout Techniques ; HLA Antigens ; Humans ; Nuclear Transfer Techniques ; Swine ; Transplantation, Heterologous

PiggyBac is a transposable DNA element originally discovered in the cabbage looper moth (Trichoplusia ni). The T. ni piggyBac transposon can introduce exogenous fragments into a genome, constructing a transgenic organism. Nevertheless, the comprehensive analysis of endogenous piggyBac-like elements (PLEs) is important before using piggyBac, because they may influence the genetic stability of transgenic lines. Herein, we conducted a genome-wide analysis of PLEs in the brown planthopper (BPH) Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), and identified a total of 28 PLE sequences. All N. lugens piggyBac-like elements (NlPLEs) were present as multiple copies in the genome of BPH. Among the identified NlPLEs, NlPLE25 had the highest copy number and it was distributed on five chromosomes. The full length of NlPLE25 consisted of terminal inverted repeats and sub-terminal inverted repeats at both terminals, as well as a single open reading frame transposase encoding 546 amino acids. Furthermore, NlPLE25 transposase caused precise excision and transposition in cultured insect cells and also restored the original TTAA target sequence after excision. A cross-recognition between the NlPLE25 transposon and the piggyBac transposon was also revealed in this study. These findings provide useful information for the construction of transgenic insect lines.
Amino Acid Sequence ; Animals ; Animals, Genetically Modified ; DNA Transposable Elements/genetics* ; Hemiptera/genetics* ; Transposases/genetics*