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At least 1,297 records · Page 72Linked to original sources
PubMed2005

Embryonic stem cells: a perspective.

Embryonic stem (ES) cells are proliferating tissue-culture cells which are embryonic in origin and retain the full lineage and differentiative capacity of the early mammalian embryo. Only mouse ES cells have been fully characterized but similar cultures have been isolated from numbers of other mammalian embryos including, notably, human. ES cells can differentiate either in vivo in the context of an embryo or equivalently in vitro. Their ability to undergo genetic alteration and selection in vitro followed by embryonic development in vivo has led to their extensive use as a vector for mammalian genetic engineering. This is not an application for human ES cells but their ability to differentiate in vitro into a plethora of specific tissue precursors has led to scenarios for their use in cellular and tissue engineering therapies. Ethical and practical problems for the provision of ad hominem human ES cells remain. Knowledge from the mouse system may aid our understanding of the relationship between ES cells and embryos.

Animals↗
PubMed2005

[Cloning and characterization of an harpin-encoding gene from Xanthomonas axonopodis pv. glycines required for hypersensitive response on nonhost plant tobacco].

An hpa1 gene was cloned into an expression vector, pET30a(+), from the genomic DNA of Xanthomonas axonopodis pv. glycines (Xag), the causal agent of soybean bacterial pustule, with degenerated primers by polymerase amplification reaction (PCR). The gene product was extracted from the conjugate (BHR-3) of BL21 (DES) with the recombined vector pHR3 after the engineering strain was induced by IPTG in LB medium. The SDS-PAGE gel showed that the gene product was 15.1kD. The product was heat-stable (10 min at 100 degrees C), protease K sensitive, and able to trigger hypersensitive response (HR) in common tobacco, but was unable to elicit HR in NahG transgenic tobacco in which salicylic acid accumulation was abolished. Moreover, the HR elicitation of the protein in tobacco was dispelled by eukayotic metabolic inhibitors, actinomycin D, cycloheximide and LaCl3. The 402 bp hpa1 gene in this study putatively encoded a 133 ammonia acid protein of which glycine (G) was rich with 21.1%. Sequence comparison indicated that the hpa1 gene and its protein was 51.4% - 93.8% identity with those of Xanthomonas oryzae pv. oryzae and other Xanthomonas species and pathovars. Alignments of harpin proteins of Xanthomonas genus displayed that the glycine-rich region with GGG-GG motif was variable. The comparison also showed that the harpin-encoding gene of Xag (nominated here as hpa1(Xag)) did not possess any similarity with that of Erwinia amylovora, Pseudomonas syringae and Ralstonia solanacearum at nucleotide and protein levels. It is concluded that hpa1(Xag) gene encodes an harpin protein which elicits a typical HR in nonhost tobacco.

Amino Acid Sequence↗
PubMed2006

[Construction and experimental immunity of recombinant replication-competent canine adenovirus type 2 expressing hemagglutinin gene of H5N1 subtype tiger influenza virus].

H5N1 highly pathogenic avian influenza virus was highly pathogenic and sometimes even fatal for tigers and cats. To develop a new type of vaccine for Felidae influenza prevention, recombinant replication-competent canine adenovirus Type 2 expressing hemagglutinin gene of H5N1 subtype tiger influenza virus was constructed. A/tiger/Harbin/01/2003 (HSN1) HA gene was cloned into PVAX1. The HA expression cassette which included CMV and HA and PolyA was ligated into the E3 deletion region of pVAXdeltaE. The recombinant plasmid was named pdeltaEHA. The pdelta EHA and the pPoly2-CAV2 were digested with Nru I /Sal I, respectively. The purified Nru I/Sal I DNA fragment containing the HA expression cassette was cloned into pPoly2-CAV2 to generate the recombinant plasmid pCAV-2/HA. The recombinant genome was released from pCAV-2/HA, and was transfected into MDCK cells by Lipofectamine. The recombinant virus named CAV2/HA was gained. Anti-H5N1 influenza virus HI antibody (1:8 - 1:16) was detected in the cat immunized with CAV-2/HA.

Adenoviruses, Canine↗
PubMed2006

Interactions between the cytomegalovirus promoter and the estrogen response element: implications for design of estrogen-responsive reporter plasmids.

We aimed to produce an estrogen-responsive reporter plasmid that would permit monitoring of estrogen receptor function in the uterus in vivo. The plasmid pBL-tk-CAT(+)ERE was induced by estrogen in bovine endometrial stromal cells. When the CAT gene was replaced by the secreted alkaline phosphatase SeAP, the resulting construct pBL-tk-SeAP(+)ERE remained estrogen responsive. However when the tk promoter was replaced by the cytomegalovirus (cmv) promoter, the resulting plasmid (pBL-cmv-SeAP(+)ERE) was not estrogen responsive. Inhibition of ERE function was not due to an effect in trans or due to lack of estrogen receptor. It was not due to an interaction between the cmv promoter and the SeAP gene. cmv promoter function was dependent on NF-kappaB, and mutagenesis in the NF-kappaB sites reduced basal reporter expression without imparting responsiveness to estrogen. A mutation in the TATA box also failed to impart estrogen responsiveness. Modeling of DNA accessibility indicated the ERE was inserted at a site accessible to transcription factors. We conclude that the cmv promoter inhibits ERE function in cis when the two sequences are located in the same construct, and that this effect does not involve an interaction between cmv and reporter gene, NF-kappaB sites or the TATA box, or DNA inaccessibility.

Animals↗
PubMed2006

[The technologies of genetic engineering in treatment of chronic lower limb ischemia].

The article contains experimental data on angiogenesis stimulated by plasmid containing the angiogenin gene. After the introduction of the gene construction, the number of capillars in the chorion-allantois membrane increases 2 to 3 times; in an ischemized limb of a rat it increases by 20 to 30%. Intramuscular administration of genetic engineering construction to patients with chronic lower limb ischemia improved the patients' condition, consisting in an increase in painless walking distance and ankle-brachial index, as well as in trophic defect healing and the betterment of muscular perfusion. Positive effects were noted after 2 to 4 weeks of treatment and remained during 6 to 24 months. There were no side-effects, except low grade fever during 1 to 2 days.

Adenoviridae↗
PubMed1990

Evaluation of vaccines designed to induce protective cellular immunity against the Plasmodium yoelii circumsporozoite protein: vaccinia, pseudorabies, and Salmonella transformed with circumsporozoite gene.

In an attempt to induce a protective cytotoxic T-cell mediated immunity against sporozoites of Plasmodium yoelii, the gene encoding the P. yoelii circumsporozoite (CS) protein was engineered into three live vectors: vaccinia, attenuated pseudorabies, and attenuated Salmonella typhimurium. Balb/c mice were immunized with 1-4 doses of 10(8) pfu of the vaccinia construct (IP), 3 doses of 10(5), 10(6) or 10(7) pfu of pseudorabies construct (IV), and 3 doses of 10(9) salmonella transformants (orally). In the case of vaccinia and pseudorabies constructs, an excellent immune response was obtained as measured by antibodies to sporozoites. No protection or delay in prepatent period was seen in any of the experimental animals when challenged with 200 (vaccinia, pseudorabies) or 100 (salmonella) sporozoites, although mice immunized with irradiation-attenuated sporozoites were consistently protected against challenge with greater than 10(4) sporozoites. Since other vaccinia, pseudorabies, and salmonella CS constructs have been shown to induce cytotoxic T lymphocytes (CTL) against the CS protein, it is likely that CTL against the CS protein were induced during these studies. It is currently unclear if the vaccines did not induce the appropriate CTL or inadequate numbers of CTL, or if CTL against the P. yoelii CS protein are inadequate to protect against sporozoite challenge.

Animals↗
PubMedDate not supplied

[The nature of N-terminal signal sequence determines the type of intracellular distribution and effectiveness of export of human growth hormone in Saccharomyces cerevisiae].

Various N-terminal signal peptides (SP) were tested to investigate a human growth hormone (hGH) synthesis, processing and intracellular sorting in yeast. Maximal level of hGH was observed in the case when the mature hGH gene was placed under the control of PHO5 promoter. In this case about 90% of hGH was localized in the cytosol, but some portion was trustworthly detected in microsomes and periplasma in spite of the absence of SP. Addition of own or PHO5 SP resulted in lowering of the synthesis and a difficulty in the prehGH processing. In this case the immunoreactive products were localized mainly in periplasma and vacuoles and to a lesser degree in the cytosol. When hGH gene was placed under the control of the yeast MF alpha 1 promoter and alpha-factor preprosegment was used as SP more then a half (67%) of hGH processed correctly was exported in a medium, the rest was detected in vacuole (17%) and periplasma (8%).

Amino Acid Sequence↗
PubMed1989

SRP-dependent membrane integration of the beta-subunit of Na+,K+-ATPase.

cDNA clones coding for either full-length or truncated forms of the beta-subunit of the Na+,K+-ATPase from pig kidney were engineered into a transcription vector based on a T7 promotor. In vitro transcription and subsequent translation of the mRNA in the presence of rough microsomes (RM) yielded beta-subunit molecules that were N-glycosylated and correctly inserted into the membrane. The signal peptide was not cleaved off. This membrane integration was found to be dependent on the function of the signal recognition particle (SRP). Several lines of evidence suggest that the hydrophilic aminoterminal domain of 34 amino acid residues preceding the postulated signal sequence is located on the cytoplasmic side whereas the carboxyterminal glycosylated domain is located on the exoplasmic side of the ER (endoplasmic reticulum)-membrane (type II membrane protein).

Animals↗