Divergent selection for relative breast yield at 4 D posthatch and the effect on embryonic and early posthatch development.

Genetic selections for growth promotion in poultry have been highly successful in improving growth, yield, and feed conversion in the modern broiler. These selections have focused on the use of hypertrophy, the increase of muscle fiber size to improve growth. Muscle growth however is not limited solely to hypertrophy but is largely attributable to both hypertrophy and hyperplasia, the increase in muscle fiber number. As muscle fiber size has been theorized to reach an eventual physiological limit, it was determined to develop a novel method of selection focusing on hyperplasia. Divergent selection for 4-day relative breast yield (BY4) was chosen as it is believed to occur at point at which muscle cell number per gram is maximized and satellite cell activity is higher than later in life. Using a random bred control population, divergent selection was undergone for BY4. The 2 broiler lines divergently selected for BY4 are noted as the high and low BY4 lines, respectively (high 4-day breast yield and low 4-day breast yield). Heritability estimates for selection of 4-day breast percentage in the upward and downward directions were 0.63 and 0.44, respectively. Divergent selection resulted in clear divergence in BY4 and shows promise in utilizing BY4 to promote broiler growth and body composition.

Plexogenic arteriopathy in broiler lungs: Evaluation of line, age, and sex influences.

Plexiform lesions form in the terminal pulmonary arterioles of human patients suffering from prolonged pulmonary arterial hypertension. Plexiform lesions also develop in broiler lungs, but lesion incidences are not strongly correlated with sustained pulmonary hypertension as reflected by right to total ventricular weight (RVTV) ratios. The present study was conducted to assess plexiform lesion incidences in broiler lines that have been divergently selected for susceptibility or resistance to pulmonary hypertension. Broilers from susceptible (SUS) and resistant (RES) lines were reared together and only clinically healthy (nonascitic, noncyanotic) individuals were evaluated to minimize potential line differences in cardiopulmonary hemodynamics. The objective was to determine if an innate genetic predisposition for plexogenic arteriopathy would be exposed in SUS broilers when compared with RES broilers in the absence of extreme differences in cardiopulmonary hemodynamics. Broilers up to 12 wk age from the SUS and RES lines had essentially equivalent BW, indices of cardiopulmonary function (left ventricle + septum weight, total ventricle weight, and RVTV ratios), and lung volumes within a sex. Average RVTV ratios for broilers from both lines were indicative of normal pulmonary arterial pressures at all ages sampled. Nevertheless, plexiform lesions were detected in SUS and RES broiler lungs immediately posthatch and thereafter at all ages sampled. Lesion incidences were consistently low and did not differ between the lines within any of the sampling ages. This evidence demonstrates that plexiform lesions develop extremely rapidly in broiler chicks, apparently without the prerequisite for vascular stress caused by severe, prolonged pulmonary arterial hypertension. No innate genetic predisposition for complex vascular lesion development appeared to exist in the SUS line when compared with the RES line.

Isolation and characterization of a flavonoid 3'-hydroxylase cDNA clone corresponding to the Ht1 locus of Petunia hybrida.

We have isolated a cDNA clone that corresponds to the Ht1 locus of petunia which controls the hydroxylation of dihydrokaempferol to dihydroquercetin and of naringenin to eriodictyol by the action of flavonoid 3'-hydroxylase (F3'H). The cDNA encodes a 512 amino acid polypeptide with regions of similarity to petunia flavonoid 3',5'-hydroxylases (F3'5'H). Both F3'H and F3'5'H are cytochromes P450 and are key enzymes in the flavonoid pathway leading to the production of the coloured anthocyanins. The F3 'H transcript is most abundant in petals from flowers at an early stage of development and levels decline as the flower matures. Transcripts are also detected in the ovaries, sepals, peduncles, stems and anthers of the petunia plant. No or very reduced levels of transcripts are detected in ht1/ht1 lines. This is the first report of isolation of a F3 'H cDNA clone from any species.

The gamma-subunit of spinach chloroplast ATP synthase: isolation and characterisation of cDNA and genomic clones.

cDNA and genomic clones encoding the complete precursor polypeptide of the gamma-subunit of spinach chloroplast ATP synthase have been isolated and characterised. The longest cDNA (1320 bp), selected from a lambda gt11 spinach cDNA library, encoded a 364 amino acid residue protein (Mr 40,028) that included a putative 41 residue N-terminal transit peptide. All the gamma-subunit cDNAs analysed were derived from the same gene and Southern blot analysis of Bam HI restricted spinach DNA showed only one hybridising band (ca. 15 kb). Analysis of the cloned 15 kb genomic fragment, selected from a lambda EMBL4 spinach DNA library with a cDNA probe, confirmed there was a single gene for the gamma-subunit. Sequencing, primer extension and northern blot analysis showed the gene contains two introns, 1066 and 665 bp in length, a 173 bp 5' untranslated region and a 213 bp 3' untranslated region. A 1450 nucleotide gamma-subunit transcript was detected in RNA from light-grown and dark-grown spinach.

Spinach chloroplastic carbonic anhydrase: nucleotide sequence analysis of cDNA.

We have determined the nucleotide sequence of a cDNA encoding spinach (Spinacia oleracea) chloroplastic carbonic anhydrase (CA). The open reading frame encodes a protein consisting of a transit peptide and a mature CA protein with a predicted mass of 24, 116 daltons. This represents the first report of a nucleotide sequence of a plant CA.

The chloroplast genes encoding subunits of the H(+)-ATP synthase.

Three CF1 and three CF0 subunits of the chloroplast H(+)-ATP synthase are encoded on the chloroplast genome. The chloroplast atp genes are organized as two operons in plants but not in the green alga, Chlamydomonas reinhardtii. The atpBE or ß operon shows a relatively simple organisation and transcription pattern, while the atpIHFA or α operon is transcribed into a large variety of mRNAs. The atp genes are related to those of cyanobacteria and, more distantly, to those of non-photosynthetic bacteria such as E. coli, suggesting a common origin of most F1F0 ATP synthase subunits. Both the chloroplast and cyanobacterial ATP synthases have four F0 subunits, not three as in the E. coli complex. The proton pore of the CF0 is proposed to be formed by the interaction of subunits III and IV.

A gene cluster in the spinach and pea chloroplast genomes encoding one CF1 and three CF0 subunits of the H+-ATP synthase complex and the ribosomal protein S2.

The regions of the spinach and pea chloroplast genomes containing the ATP synthase genes atpA, atpF and atpH have been sequenced. The encoded proteins, CF1 alpha, CF0I and CF0III, are well conserved between spinach and pea, and analogous to the alpha, b and c subunits of the Escherichia coli ATP synthase complex. The atpF gene is split by a single intron, and the exon/intron boundaries have been defined by isolating and sequencing a partial cDNA clone. Two other genes, designated atpI and rps2, located upstream from atpH, have also been sequenced. They encode a 27,000 Mr hydrophobic protein analogous to the F0a subunit of E. coli ATP synthase and a basic protein analogous to the S2 protein of the E. coli 30 S ribosomal subunit. Transcriptional analysis by electron microscopy of RNA-DNA hybrids, Northern blotting and primer extension experiments shows that these genes are transcribed and processed into a complex set of transcripts, with 5' ends mapping upstream from the rps2, atpI and atpH genes.

Thermodynamics of the partition of 8-quinolinol between several organic solvents and aqueous buffers.

The partition coefficients of 8-quinolinol between water and benzene, nitrobenzene, toluene and chloroform have been determined as a function of temperature, and values of DeltaH and DeltaS determined for each. Values of the dissociation constant for protonated 8-quinolinol are reported as a function of temperature.

Effect of salts on the partition of 8-quinolinol.

The effect of inert salts on the partition of 8-quinolinol between benzene and water was determined. For the salts investigated, the relation log K(D') = I + k(3),mu was demonstrated, as expected from the Setschenow equation. The salting out order observed is KCl > NaCl > KNO(3) > NaClO(4).