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J E Mayfield

Publications and source records attributed to J E Mayfield.

At least 37 records · Page 2Linked to original sources
PubMed1989

Molecular analysis of cytoplasmic genetic variation in Holstein cows.

Mitochondrial DNA from Holstein maternal lineages implicated to express cytoplasmic genetic effects on lactation traits was subcloned and screened for molecular polymorphisms. Sixteen of 35 lineages sampled differed from the most common mitochondrial DNA form by at least one restriction endonuclease cleavage site in the 4.3 kilobase segment examined. Variation existed in the region that regulates DNA replication and transcription as well as in transfer and ribosomal ribonucleic acid coding regions of the DNA. The index of nucleotide diversity calculated from polymorphism frequencies indicated that the minimum extent of variation between two random lineages was 1.16 x 10(-4) nucleotide differences per base pair in the segment examined. Presence of a HpaII marker near nucleotide 360 was associated with lower (P less than .001) milk fat percentages. Molecular markers indicated that pedigrees may not be sufficient to separate true cytoplasmic lineages for quantitative genetic analyses. These findings provide a molecular genetic basis for further study of cytoplasmic effects on phenotypic variation in Holstein cattle.

Animals↗
PubMed1989

Characteristics of mammary mitochondria in lines of mice genetically divergent for milk production.

The purpose of this study was to determine the relationship of mitochondrial proliferation and ATP production to milk production in two lines of mice that were genetically divergent for milk production. Milk production differed between high production and low production lines by .8 phenotypic standard deviations as determined by cross-fostered litter weight gain from 1 to 12 d postpartum. Mammary weight, mammary total DNA, and RNA:DNA ratio were greater in glands of high line mice. Mammary DNA and protein, expressed per gram mammary tissue, were similar between lines. Mammary mitochondrial mass per gland differed after six generations of divergent selection. Rates of succinate-supported ATP production and ADP:O of isolated mitochondria differed, but the rate of pyruvate-supported ATP production did not differ between lines. Differences between selection lines in mitochondrial mass and in the efficiency of succinate use for support of ATP production were probable consequences of selection for divergent milk production.

Adenosine Triphosphate↗
PubMed1989

Identification of a virulence factor for Brucella abortus infection in BALB/c mice.

Immunogenic or pathogenic factors of recombinant proteins (rBCSP20, rBCSP-31, and rBCSP45 of Brucella abortus strain 19) for mice were compared with factors of a proteinase K-treated lipopolysaccharide extracted from B abortus strain 2308. Mice were vaccinated with 4 products, using different inoculation schedules and were challenge exposed with a virulent culture of B abortus strain 2308. Blood samples were collected 2 weeks after vaccination and at necropsy and sera were obtained. Spleens were cultured for B abortus at necropsy (3 to 4 weeks after challenge exposure). Mice given proteinase K-treated lipopolysaccharide alone or in conjunction with rBCSP20 or rBCSP45 proteins were protected, but mice given rBCSP31 on the same day as challenge exposure were not. Vaccination with recombinant proteins alone neither provide protection nor significantly (P greater than 0.05) increase the pathogenic effect of the challenge-exposure culture. Seemingly, rBCSP31 might be a virulence factor of B abortus.

Animals↗
PubMed1988

The cloning, expression, and nucleotide sequence of a gene coding for an immunogenic Brucella abortus protein.

Brucella abortus is the causative agent for brucellosis in cattle and man. Development of a single diagnostic test for the differentiation of vaccinated from infected animals and the development of a nonviable 'subunit' vaccine are top priorities of the brucellosis research program in the United States. Preliminary evidence previously showed that a purified 31-kDa protein (thought to be localized at or near the bacterial cell surface) protects against experimental brucellosis in rodents. The gene for this 31-kDa protein has now been cloned in Escherichia coli. The protein is expressed well, apparently from its native promoter, when placed in several different E. coli plasmids. The nucleotide sequence of the flanking and encoding sequences has been determined, and comparison with the N-terminal amino acid (aa) sequence of the mature protein indicates the presence of a putative 28-aa signal sequence. The availability of the 31-kDa protein free of Brucella contaminants now allows rigorous study of the immunological properties of this protein.

Amino Acid Sequence↗
PubMed1988

Conservation of antigenicity in a 31-kDa Brucella protein.

A 31-kilodalton (kDa) protein extracted from Brucella abortus was previously cloned into Escherichia coli and expressed at high levels. The E. coli-derived protein can be purified by a simple 2-step procedure entailing detergent extraction followed by ion-exchange chromatography. Subsequent analyses show that the E. coli-derived protein is identical to the Brucella-derived protein in molecular weight and isoelectric point. A partial amino acid sequence of the N-terminus of the protein of E. coli origin matches the predicted sequence, based on DNA sequence data. Using specific antiserum raised against the E. coli-derived protein, 34 strains of Brucella, representing all 6 recognized species, were examined for expression of the 31-kDa protein by Western blotting. This protein was detectable in all, but one Brucella species (B. ovis), including all 8 biovars of B. abortus tested. This degree of conservation supports further study of the 31-kDa protein for potential exploitation as a vaccine or diagnostic component.

Amino Acid Sequence↗
PubMed1987

Mapping bovine herpesvirus type 1 latency-related RNA in trigeminal ganglia of latently infected rabbits.

Here we have used the bovine herpesvirus type 1 (BHV-1) rabbit model together with in situ nucleic acid hybridization to identify and map viral RNA present in latently infected neurons. Radioactively labeled cloned HindIII fragments representing most of the BHV-1 genome (Cooper strain) were individually hybridized to sections of trigeminal ganglia taken from rabbits during acute and latent stages of infection. Whereas all viral genomic fragments hybridized to lytically infected tissue culture cells and to acutely infected ganglia, only HindIII fragment D (map units 0.734 to 0.842) hybridized to latently infected ganglionic neurons. Additional in situ hybridization experiments using subcloned fragments of HindIII-D further mapped the latency-related viral RNA to a 1.9-kilobase region (map units 0.734 to 0.748) of the viral genome. These results indicate that BHV-1 gene transcription is restricted during the latent phase of infection; further, they suggest that specific viral transcription may be involved in establishment or maintenance of latent BHV-1 infection.

Animals↗
PubMed1986

Bovine DNA contains a single major family of interspersed repetitive sequences.

A major family of short, interspersed, repeated sequences in the bovine genome has been characterized. This family makes up the majority of all non-satellite repetitive DNA or about 6% of the bovine genome. It is estimated that there are at least 600 000 copies of this family interspersed among non-repetitive DNA sequences. Sequence analysis shows that this family includes sequences reported previously by Watanabe et al. (Nucleic Acids Res. 10, 1459-1469, 1982) and is distantly related to the human Alu sequence family.

Animals↗
PubMed1986

Carbohydrate and protein contents of grain dusts in relation to dust morphology.

Grain dusts contain a variety of materials which are potentially hazardous to the health of workers in the grain industry. Because the characterization of grain dusts is incomplete, we are defining the botanical, chemical, and microbial contents of several grain dusts collected from grain elevators in the Duluth-Superior regions of the U.S. Here, we report certain of the carbohydrate and protein contents of dusts in relation to dust morphology. Examination of the gross morphologies of the dusts revealed that, except for corn, each dust contained either husk or pericarp (seed coat in the case of flax) fragments in addition to respirable particles. When viewed with the light microscope, the fragments appeared as elongated, pointed structures. The possibility that certain of the fragments within corn, settled, and spring wheat were derived from cell walls was suggested by the detection of pentoses following colorimetric assay of neutralized 2 N trifluoroacetic acid hydrolyzates of these dusts. The presence of pentoses together with the occurrence of proteins within water washings of grain dusts suggests that glycoproteins may be present within the dusts. With scanning electron microscopy, each dust was found to consist of a distinct assortment of particles in addition to respirable particles. Small husk fragments and "trichome-like" objects were common to all but corn dust.

Amino Acids↗
PubMed1983

Cloning and cleavage site mapping of DNA from bovine herpesvirus 1 (Cooper strain).

Sequences representative of most of the bovine herpesvirus 1 (Cooper strain) DNa were cloned in the plasmid vector pBR322 at the HindIII site. EcoRI, HpaI, and BamHI restriction endonuclease sites were mapped in each of the cloned fragments, and this information was used to construct a restriction endonuclease cleavage site map of the entire viral genome for the four enzymes.

Animals↗
PubMed1982

Major high mobility group like proteins of Drosophila melanogaster embryonic nuclei.

Nuclei from Drosophila melanogaster embryos contain three major proteins which are extracted by 0.35 M NaCl and by 2% perchloric acid. One of these is histone H1, and we refer to the other two as A63 and A13 in accordance with their molecular weights determined by electrophoresis on sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gels (63,000 and 13,000, respectively). The molecular weight of A13, based on its amino acid composition, is approximately 10,000. The amino acid analyses of A63 and A13 show that both of these proteins have high proportions of acidic and basic amino acid residues, a property characteristic of the high mobility group proteins isolated from vertebrate tissues. While A13 comigrates with histone H2A on NaDodSO4-polyacrylamide gels and with H2B on acid/urea gels, it can be readily resolved from the histones by Triton/acid/urea-Na DodSO4 two-dimensional electrophoresis.

Amino Acids↗
PubMed1980

The sequence organization of bovine DNA.

The organization of repetitive DNA sequences has been investigated in bovine DNA. Repetitive sequences of all kinds constitute 25% to 30% of the total. Five density satellites constitute about 20% of the genome, and most of the remainder consists of alternating repeating and nonrepeating sequences. The nonrepeating sequences have a very broad size distribution averaging 4,000 nucleotide paris in length with the longest exceeding 10,000 nucleotide pairs. The interspersed repetitive sequences are much more nearly homogeneous in size, averaging 350 nucleotide pairs in length, and are divided into 8 to 14 sequence families.

Animals↗
PubMed1978

A-T rich sequences in vertebrate DNA. A possible explanation of q-banding in metaphase chromosomes.

Partially denatured DNAs from mouse, cow, and chicken were visualized in the electron microscope by the basic protein film technique and the size and distribution of the denatured regions characterized. A-T rich sequences visualized at 15% denaturation average about 1500 bases in length for all three species and are arranged quite non-randomly in the genome. This arrangement is such that 30--50% of the entire genome contains no A-T rich DNA, and another 20% is composed about one-half of A-T rich sequences and one-half of other sequences. Comparison with DNA denaturation profiles indicates that for each organism these sequences are from 25--30% G+C and that there is very little if any DNA more A-T rich than these. Estimates from published studies of fluorescence enhancement of quinacrine bound to A-T rich DNAs suggest that the observed non-random organization of A-T rich sequences is sufficient to account for Q banding of metaphase chromosomes.

Adenine↗
PubMed1978

A protein released by DNAase I digestion of drosophila nuclei is preferentially associated with puffs.

Antisera have been produced against five molecular weight subfractions of the Drosophila proteins readily extracted from nuclei following limited DNAase I digestion. Immunofluorescence staining techniques were used to assess the distributions of these proteins in the polytene chromosomes of Drosophila. In three cases, the antigens were widely distributed; in one case, the antigens appeared to be slightly more concentrated at active loci; and in one case, the antigens were strongly concentrated at a defined set of loci, including puffs and most of the loci which are active (puffed) at some time during third instar larval and prepupal development. The latter distribution pattern differs from that of RNA polymerase. Nonhistone chromosomal proteins of this type may have a key role in establishing and/or maintaining the altered chromatin structure characteristic of the active state.

Animals↗
PubMed1977

A comparison of the differential DNA melting profiles with the CsCl density profiles of DNA from Escherichia coli, cow, mouse, rat and chicken.

Moderate resolution thermal denaturation profiles are presented for the purified DNAs from Escherichia coli, cow, mouse, rat and chicken. All show multiple thermal transitions indicative of large blocks of DNA with very similar base composition. The eucaryotes all have much more of this kind of DNA than does E. coli. The satellite DNAs of cow and mouse are clearly visible and it is likely that the other transitions represent additional families of repeated DNA.

Animals↗
PubMed1976

The fluorescence localization of mouse satellite DNA in interphase nuclei.

Nuclei from various mouse tissues exhibit a pattern of fluorescence characteristic of the cell type when stained with the fluorescent compound Hoechst 33258. When such preparations are hybridized in situ with 3H-RNA complementary to the A-T rich satellite of mouse, it is clearly seen that only the fluorescent regions of the nuclei contain the satellite DNA. Thus Hoechst 33258 allows the precise localization of satellite DNA at all stages of the mouse cell cycle.

Animals↗
PubMed1976

Double-stranded ribonucleic acid in Agaricus bisporus.

Double-stranded ribonucleic acid present in virus-infected mushrooms of Agaricus bisporus has been resolved through polyacrylamide gel electrophoresis into six molecular-weight forms. Identification of these six double-stranded ribonucleic acids in mushrooms by this procedure has proven to be a useful and diagnostic method for viral infection in the cultivated mushroom.

Agaricales↗
PubMed1975

The organization of interphase chromatin in drosophilidae: the self adhesion of chromatin containing the same DNA sequences.

Cytological evidence is presented which shows that for Drosophila virilis and Samoaia leonensis at least, each satellite DNA is condensed into a distinct heterochromatic mass during interphase. This is seen as just one example of a general phenomenon in which chromatin containing a particular DNA sequence binds to other chromatin containing the same sequence. It is proposed that DNA sequence specific proteins can account for this phenomenon.

Animals↗