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Five hundred broiler males were grown to 56 d and processed under common terms. Front halves were deboned 24 h postmortem to obtain breast fillets, and CIELAB light reflectance was measured on the skin side of each fillet 24 h later. All fillets were bagged and frozen (-20° C) for 5 ma Then the fillets exhibiting the lowest (dark), median (normal), and highest (pale) L* values 48 h postmortem were thawed (3 d at 4°C) and cooked (internal temperature 80°C). Thawing reduced the L* value in the pale fillets and increased it in the dark ones, and cooking further increased L* value and reduced the differences in L*, a*, and b* between groups. Thawing and cooking losses were not affected by initial L* value until they were combined. Total losses increased with initial L*, which was in parallel with a lower increase in thickness after cooking. [ABSTRACT FROM AUTHOR]

Eight hundred broiler males were grown to 56 d and processed under common terms while maintaining individual identity. Front halves were deboned 24 h postmortem (PM) to obtain breast fillets, and CIELAB light reflectance was immediately measured on the skin side of each fillet. Fillets were bagged and held at 4°C for 24 h, and then 20 fillets exhibiting the darkest (47.3 to 57.5), lightest (71.1 to 76.4), and median (63.7 to 64.0) L* values were selected and trimmed to best define the pectoralis major. Remeasurement of light reflectance at 48 h PM revealed decreased L* values solely associated with fillets having the highest L* at 24 h. One-half of the fillets representing each category was frozen (4 d at -20°C) and thawed (3 d at 4°C). The L* value, after thawing, decreased from the 48 h PM value, which equivalently occurred in for all L* categories. Although 48 h PM fillets from each L* category were of similar weights, their lengths and widths increased with L* value. Exudate lost with thawing increased with L* value and paralleled decreases in length and width to equalize dimensions among sources. [ABSTRACT FROM AUTHOR]

An experiment was conducted using Ross × Ross 308 males to estimate the proportion of dietary valine needed to optimize performance in broilers from 42 to 56 d of age. All birds received common feeds from 0 to 42 d, and then experimental diets were given to 56 d of age. A diet consisting of corn, soybean meal, and corn gluten meal (17% CP, 3.25 kcal of ME/g) having 0.60% valine served as basal feed. All other essential amino acids were above recommended levels. Successive additions of 0.07% of L-valine were isonitrogenously substituted for L-glutamic acid up to a total of 0.81%. Regression analysis (95% of response) indicated that valine at 0.72% of the diet maximized body weight gain, whereas 0.73% optimized feed conversion. Depot fat removed from the abdominal cavity after processing was unaltered, and weights of resultant chilled carcasses maximized at 0.73% valine in parallel with final live weight. The amount of fillets recovered from chilled carcasses optimized at 0.73% valine; however, the incidence of distinctive blood streaks in the meat (splash) progressively increased with valine as did the level of redness apart from streaking, based on light reflectance. Given lysine at 0.85%, a ratio of 0.86 with valine appears to be adequate. The presently determined requirement of 0.73% total valine (0.67% digestible) for broiler males from 42 to 56 d of age is slightly higher than the 0.70% recommended by the NRC. [ABSTRACT FROM AUTHOR]

Determines the methionine and cystine requirements of slow- and fast-feathering broiler males from three to six weeks old. Whole carcass yield of slow- and fast-feathering broiler males at six week of age after receiving feeds; Effect of increasing dietary cystine on live performance of slow-feathering birds; Composition of the common feed and sulfur amino acid-deficient basal diet.

Determines the methionine and cystine requirements of slow- and fast-feathering male broilers from zero to three weeks old. Effect of differences in feathering rate on broiler's need for cysteine; Composition of sulfur amino acid-deficient corn-soybean meal basal diet; Nitrogen balance of slow- and fast-feathering male broilers.

Examines arginine need of male broilers between the ages of 42 to 56 days, in conjunction with dietary protein approaching a previously advocated ideal amino acid pattern. Suggestion that additional amounts of arginine would be needed for immunological and connective tissue challenges.

Investigates the region of GerE required for promoter activation in bacillus subtilis. Description of GerE; Effects of single alanine substitutions on transcription; Classification of the transcriptional activators in bacteria.

Examines the effects of single base pair substitutions in the high affinity GerE protein binding site on the sigK promoter in Bacillus subtilis. Production of a protein that binds with equal affinity to two sites that differ by one base pair; Identification of the nucleotide sequence that signals recognition and binding by GerE; Mutagenesis of the DNA binding region of GerE.

Presents a speech by the mayor of Alexandria, Virginia, discussing the problems posed by the growth of open-air drug market in the city's housing projects. Lessons from the death of Corporal Charles Hill in a crack house that the housing authority was powerless to shut down; Flaws in the country's policy on the presence of a known crack house in public housing; Call for exercise of common sense and judicial responsibility.

Cites a study which examined the effects of single alanine substitutions, in an attempt to determine SpoOA activities in the bacterium Bacillus subtilis. What SpoOA is; Isolation of the derivatives of sigH mutants of SpoOA; Results of the study.

Tests whether base pair substitutions in the -10 region of a sigmaB-dependent promoter could signal its utilization by sigmaE-RNA polymerase in bacteria. Changes in specificity upon amino acid substitutions in sigmaE; Mutagenesis and expression of sigE.

Describes the cloning and characterization of spoVR, a gene from Bacillus subtilis involved in spore cortex formation. Increase in the proportion of phase-dark spores; Decrease in the accumulation of dipicolinate; Initiation of the expression of spoVR.

The allergy preventive effect of extensively (N) and partially (PH) hydrolysed cows' milk formulas compared with a regular formula (RM) was assessed in 155 infants with a family history of allergy. No cows' milk was given during the first nine months of life and no egg and fish up to 12 months of age. Breast feeding mothers avoided the same foods. At weaning the infants were randomised to one of the formula groups. The cumulative incidence of atopic symptoms at 18 months was 51, 64, and 84% in the N, PH, and RM groups, respectively. From 6 to 18 months there were significantly less cumulative atopic symptoms in the N group compared with the RM group, and significantly less than the PH group up to 6 (N = 25%; PH = 46%) and 9 months (N = 34%, PH = 58%). At 9 months significantly fewer infants in the N group (10%) than in the PH group (33%) had a positive skin prick test to eggs. The findings support an allergy preventive effect of an extensively hydrolysed formula, but not of a partially hydrolysed formula, during the first 18 months of life of high risk infants. [ABSTRACT FROM AUTHOR]

The transcriptional regulator Spo0A activates transcription from two types of promoters. One type of promoter is used by RNA polymerase containing σA, whereas the other type is used by RNA polymerase containing σH. There are Spo0A-binding sites near the -35 region of both types of promoters. It has been reported that some transcriptional regulators that bind near the -35 regions of promoters directly interact with the sigma subunit of RNA polymerase. Therefore, we looked for evidence that Spo0A interacts with both sigma factors by searching for single amino acid substitutions in these factors that specifically prevent expression from Spo0A-dependent promoters, but that do not decrease activity of Spo0A-independent promoters. Two such amino acid substitutions were isolated in σA and one was isolated in σH. The amino acid substitutions in σA prevented expression from the Spo0A-activated promoters, spollG and spollE, but expression was not impaired from the Spo0A-independent, σA-dependent promoter tms or from the Spo0A-activated, σH-dependent promoter, spollA. The amino acid substitution in σH prevented expression from the spollA promoter but not from the Spo0A-independent promoter, citGp2, which is used by σH-RNA polymerase. All of these amino acid substitutions occur in the carboxyl terminus of the sigma factors. These amino acid substitutions may define the sites of contact between the sigma factors and Spo0A. The ability of response regulators such as Spo0A to interact with multiple sigma factors may increase the variety of responses made by bacteria using a limited number of transcription factors. [ABSTRACT FROM AUTHOR]

Endospore formation in Bacillus subtilis is a morphologically complex process in which the bacterium divides into two compartments (forespore and mother cell) that follow different developmental paths. Compartment-specific transcription in the forespore is initiated by RNA polymerase containing σF, and results in the forespore-speciflc production of σG, which directs most of the subsequent forespore-speciflc transcription. The activity of σF is thought to be restricted to the forespore by the sigma factor antagonist SpollAB. We used antibodies against SpollAB to monitor its accumulation during sporulation. We found that SpollAB accumulates early after the initiation of sporulation, and that it was present in the mother-cell compartment 2h after σF became active in the forespore. SpollAB disappeared preferentially from the forespore during development, and its disappearance from the forespore compartment correlated with the activation of σG in that compartment, raising the possibility that SpollAB may be involved regulating σG activity. We tested whether SpollAB could antagonize σG activity by replacing the σH-dependent promoter that drives expression of spolllG, the structural gene for σG, with a σH-dependent promoter. This resulted in a lytic phenotype that was supressed by the simultaneous expression of a plasmid-borne copy of spollAB. This suggests that SpollAB can suppress this effect of σG Moreover, these cells formed spores efficiently. Since σG the forespore by the σF-dependent transcription of its structural gene that normally occurs in wild-type cells, the forespore-specific activity of σG required for Sporulation appears to have resulted from expression of SpollAB. [ABSTRACT FROM AUTHOR]

The coat of Bacillus subtilis spores is a multiprotein protective structure that also arbitrates many of the environmental interactions of the spore. The coat assembles around the cortex peptidoglycan layer and is differentiated into an inner and an outer layer and a crust. SafA governs assembly of the inner coat, whereas CotE drives outer coat assembly. SafA localizes to the cortex-coat interface. Both SafA and its short form C30 are substrates for Tgl, a coat-associated transglutaminase that cross-links proteins through ε-(γ-glutamyl)lysyl isopeptide bonds. We show that SafA and C30 are distributed between the coat and cortex layers. The deletion of tgl increases the extractability of SafA, mainly from the cortex. Tgl itself is mostly located in the inner coat and cortex. The localization of Tgl-cyan fluorescent protein (Tgl-CFP) is strongly, but not exclusively, dependent on safA. However, the association of Tgl with the cortex requires safA. Together, our results suggest an assembly pathway in which Tgl is first recruited to the forming spore in a manner that is only partially dependent on SafA and then is drafted to the cortex by SafA. Tgl, in turn, promotes the conversion of coat- and cortex-associated SafA into forms that resist extraction, possibly by catalyzing the cross-linking of SafA to other coat proteins, to the cortex, and/or to cortex-associated proteins. Therefore, the final assembly state of SafA relies on an autoregulatory pathway that requires the subcellular localization of a protein cross-linking enzyme. Tgl most likely exerts a "spotwelding" activity, cross-linking preformed complexes in the cortex and inner coat layers of spores. [ABSTRACT FROM AUTHOR]