摘要:

In this paper we report the complete bovine β‐lactoglobulin gene sequence, consisting of seven exons within a total of 4724 base pairs. The inferred amino acid sequence agrees completely with that determined directly for the ? variant. The bovine β‐lactoglobulin gene sequence shows 89% homology to the corresponding ovine sequence, with complete conservation of gene organization and splice sites, though a significant proportion of CG dinucleotides have been lost since the species diverged. Comparison with the previously reported cDNA sequence reveals a number of nucleotide substitutions in addition to those which distinguish the A and ? variants. Three of these are silent mutations, however it appears that the occurrence in the cDNA sequence of a Val residue at position 105 may represent a new variant provisionally designated β‐lactoglobulin K, derived from β‐lactoglobulin A.

ISSN:1049-5398    

DOI:10.1080/10495399309525781

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Bovine α‐ (IFNA),β‐(IFNB),ω‐(IFNW), trophoblast (IFNT), and γ‐(IFNG) interferon (IFN) cDNA probes were hybridized to bovine and ovine DNA samples digested with a panel of 7 restriction enzymes to characterize the hybridization patterns and genetic variability of IFN genes in these two species. Sixty percent of probe‐enzyme combinations identified RFLPs in cattle compared to 46% of the combinations in sheep. The presence of polymorphic bands in each probe‐enzyme combination was compared between species. Bovine IFNA and IFNW RFLPs were observed in cattle with all 7 enzymes while ovine IFNA and IFNW RFLPs were found with 5 and 2 enzymes, respectively. IFNG RFLPS were observed withHinD III (61% of cattle screened),TaqI (28% of sheep) andPstI (56% of sheep). IFN hybridization profiles were more complex in sheep, but RFLPs were more common in cattle. The most useful enzyme to screen for IFN RFLPs was found to beHinD III in cattle andTaqI in sheep.

ISSN:1049-5398    

DOI:10.1080/10495399309525782

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A simple device was used to collect milk throughout a lactation from rabbit does. Does were milked everyday (ED), every other day (EOD), or twice a day (2X). Litters and nest boxes were removed from 2X does on day 2 of lactation while litters were present throughout lactation in does milked ED or EOD. Lactation was abruptly terminated in 2X does and the mammary glands involuted between 48 and 60 hours after pup removal. Approximately 600 ml of milk were collected from EOD does while 1400 ml were collected from ED does. The length of lactation was also extended in ED does. The concentration of fat (21 to 24%) and protein (12 to 16%) remained relatively constant throughout lactation. These studies suggest that the rabbit may be an excellent model to study transgenic production of Pharmaceuticals in milk.

ISSN:1049-5398    

DOI:10.1080/10495399309525783

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Cattle were examined for restriction fragment length polymorphisms (RFLPs) at the myogenicbmyfgene locus.TaqI, PvuII, BstEII, andHindIII were used to analyze allele frequencies and linkage equilibrium. Strong disequilibrium was found between twoTaqlpolymorphisms and other RFLPs. Polymorphisms at this locus may prove useful in determining the role played bybmyfin the development and characteristics of muscle in cattle.

ISSN:1049-5398    

DOI:10.1080/10495399309525784

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Genetic resistance to bovine spongiform encephalopathy (BSE) may be determined in part by alleles of the prion gene. The frequencies of prion allelic structural variants and a silent marker were determined by nucleic acid analysis in selected United States bulls. The frequency of a variant of the prion gene reported in BSE‐affected British bulls was 0.97 in 210 U.S. Holstein bulls and 0.99 in 46 U.S. Hereford bulls examined in the present study. Near uniformity of the U.S. cattle population for this allele may constitute a risk factor if an association of prion genotype with BSE susceptibility is established in the future.

ISSN:1049-5398    

DOI:10.1080/10495399309525785

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The amphotropic murine leukemia virus (MLV)envgene has been the most commonly used among the three kinds of MLV in retroviral vector systems due to its wide host range. On bovine target cells, however, we demonstrated that retroviral vectors packaged with xenotropic MLV envelope proteins were more than 500‐fold more infectious compared to the same vectors packaged with amphotropic MLV envelope proteins. This result indicates that the xenotropic MLVenvgene is potentially more useful than the amphotropic MLV env in experiments designed to transfer genes to cells derived from non‐murine species. In a test of internal promoter activity in a retroviral vector, herpes simplex virus type 1 thymidine kinase (TK), simian virus 40 (SV40), human histone H4 and rat β‐actin promoters worked well in bovine cells. Finally, by co‐culture of bovine blastocysts and xenotropic MLV‐based virus‐producing cells, we infected the embryos with viruses encapsidated with xenotropic MLV envelope proteins. Infection of the embryo was confirmed by detection of the embryonic cells expressingE. coli β‐galactosidase gene under the rat β‐actin promoter which was transferred by retrovirus‐mediated infection.

ISSN:1049-5398    

DOI:10.1080/10495399309525786

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The efficacy of using liposomes to transfer DNA to chicken sperm cells was investigated. Liposomes were prepared from dilauroyl (12:0) phosphatidylcholine (DLPC), dimyristoyl (14:0) phosphatidyl choline (DMPC), dipalmitoyl (16:0) phosphatidylcholine (DPPC), egg yolk phosphatidylcholine (EYPC) or lipids extracted from sperm cell membranes. The efficiency of trapping of DNA into the liposomes, transfer of the DNA from the liposomes to the sperm cells and the effect of the liposomes on the fertilizing ability of the sperm cells were determined. Increasing the concentration of lipid in the liposome preparations increased the trapping efficiency of DNA into liposomes but lowered the transfer of DNA to sperm. Including stearylamine (SA) in the liposomes increased the incorporation of DNA into the liposomes and the DNA transfer to sperm cells, while including lauroyllysophosphatidylcholine (LPC) along with SA resulted in the highest transfer efficiency from liposomes to sperm. The transfer of DNA from liposomes to sperm cells was lowered by increasing the number of sperm cells, while decreasing the number of sperm cells lowered the fertility. The sperm cells remained fertile after exposure to low levels of DPPC or lipofectin reagent or to high levels of SA and LPC. The best conditions for liposome‐mediated gene transfer to chicken sperm cells are thus using either lipofectin reagent at .006 to .06 μmol/ml and 5 × 107sperm or with DPPC liposomes comprised of 10 μmol/ml total lipid including 5 mol% SA and 20 mol% LPC with 2.5 × 108sperm cells. The use of liposomes to enhance the transfer of DNA to sperm cells may make the use of sperm cells as gene transfer vectors possible.

ISSN:1049-5398    

DOI:10.1080/10495399309525787

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

To test the mouse mammary tumor virus (MMTV) promoter as an inducible mammary‐specific promoter, we have produced 3 lines of transgenic mice carrying bovine αS1 casein cDNA under the control of MMTV promoter. The RNA analysis showed that in line 27, heterozygotes expressed 25%, and homozygotes 37% of the endogenous αSI casein mRNA of a mid‐lactation cow. Dexamethasone increased expression by about 3 fold in both heterozygotes and homozygotes. A similar increase in the level of mRNA was observed in both heterozygotes and homozygotes from line 42 with/without induction by dexamethasone. The transgenes were expressed predominantly in the mammary gland with low levels in the salivary gland, spleen, lung, and kidney. Their expression in mammary glands was lactation‐specific. The offspring from lines 27 and 42 expressed a high‐level bovine αS1 casein in their milk. Their expression in milk were 0.21 and 0.11 g/L for heterozygotes, 0.36 and 0.19 g/L for homozygotes, respectively. Dexamethasone further increased the levels of expression by approximately two fold for both heterozygotes and homozygotes.

ISSN:1049-5398    

DOI:10.1080/10495399309525788

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The 5’ flanking region of the α‐lactalbumin gene fromBos indicus(Brahman) andBos taurus(Holstein) have been sequenced. The sequences were compared to detect potential sequence variations. The 538 bp of 5’ flanking region contained nine sequence variations between the two breeds. Seven of the variations occur in the 5’ flanking region of the α‐lactalbumin gene and two occur in the region encoding the 5’ untranslated region of the mRNA. Seven of the variations are conservative purine to purine or pyrimidine to pyrimidine variations, while two are purine to pyrimidine variations.

ISSN:1049-5398    

DOI:10.1080/10495399309525789

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:1049-5398    

DOI:10.1080/10495399309525780

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor