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Biomedical subjects

G C Harris

Publications and source records attributed to G C Harris.

At least 55 records · Page 3Linked to original sources
PubMed1988

Influence of storage container for frozen-thawed chicken semen and frequency of insemination on fertility and its duration.

Pooled semen was diluted with Lake's solution containing 10.8% (v/v) glycerol. Aliquots of 1.2 mL and .5 mL were transferred to 1.8-mL capacity plastic vials and .5-mL capacity plastic straws, respectively. Semen was processed at 5 C, frozen by cooling at a rate of 3 C/min to -35 C, then plunged in liquid nitrogen. Samples were thawed at 5 C, diluted stepwise, centrifuged, and resuspended with nonglycerolized diluent at 5 C. Fertility and its duration were measured after single or double (insemination on 2 consecutive days) insemination. No significant differences were found in fertility percentages between semen samples frozen and stored in the two types of containers. However, fertility percentages were significantly higher for eggs laid on Days 2 to 5 after double insemination than for eggs laid after single insemination. No such differences were noted in the fertility of eggs laid on Days 2 to 7. Duration of fertility was significantly longer for semen frozen in plastic vials than for semen frozen in straws.

Animals↗
PubMed1988

Ascorbic acid and acetylsalicylic acid (aspirin) in the diet of broilers maintained under heat stress conditions.

Male broiler chicks were grown to 21 days of age under normal conditions, then placed in environmental chambers maintained under constant (24 C) or cyclic (24 to 35 C) heat conditions. Chicks were acclimated for 1 wk on a standard grower basal diet. Standard grower basal diets were fortified with 0, 125, 250, 500, or 1,000 ppm coated ascorbic acid (AA) or 0, 125, 250, or 500 ppm acetylsalicylic acid (ASA). Test diets were fed for 14 days in two separate studies. Cyclic heat conditions reduced feed intake and significantly reduced weight gains in both trials. Feed efficiency was not significantly affected by heat stress. Neither AA or ASA had beneficial effects on broiler growth or feed efficiency.

Animals↗
PubMed1986

The association of ribulose-1,5-bisphosphate carboxylase with phosphoriboisomerase and phosphoribulokinase.

RuBPCase from peas showed Ribose-5-phosphate and Ribulose-5-phosphate dependent CO2 fixation when purified on sucrose gradients or by conventional methods. If purification was done in the presence of 20 mM MgCl2 and 20-25 mM NaHCO3 RuBPCase showed higher Ribose-5-phosphate and Ribulose-5-phosphate dependent CO2 fixation rates. Partially purified phosphoriboisomerase, phosphoribulokinase and RuBPCase from spinach could be reassociated in vitro.

Aldose-Ketose Isomerases↗
PubMed1986

Mannose metabolism in corn and its impact on leaf metabolites, photosynthetic gas exchange, and chlorophyll fluorescence.

When intact corn leaves were provided millimolar concentrations of d-mannose through the transpiration stream photosynthesis was inhibited; 5.7 millimolar resulted in a 50% inhibition of the carbon exchange rate. This inhibition was partially reversible by the addition of orthophosphate to the feeding solution. Mannose metabolism by corn leaves was limited in that it did not act as a resource for sucrose or starch synthesis. Mannose 6-phosphate accumulated in the leaf tissues and was slowly metabolized by a pathway involving mannose 1-phosphate. Correlated with the mannose-6-phosphate accumulation were decreases in ATP, orthophosphate, sucrose, and phosphoenolpyruvate and increases in starch and maltose. When provided in the transpiration stream mannose had access to both mesophyll and bundle sheath cells. Mannose feeding led to oscillations in steady state chlorophyll fluorescence emission (680 nanometers) and an elimination of the Kautsky effect during fluorescence induction. Pyridoxal 5-phosphate and 2,4-dinitrophenol were found to be inhibitors of CO(2) exchange when provided in the transpiration stream of intact corn leaves. However, Pyridoxal 5-phosphate induced a quenching of steady state fluorescence while 2,4-dinitrophenol led to an increase in fluorescence emission.

Journal Article↗
PubMed1986

Effects of adding acid or base to the diet on semen of heat-stressed, aging broiler breeder males.

Males were fed breeder basal diet, basal diet + .67 g NaHCO3, + .43 g NH4Cl, or + .86 g NH4Cl/100 g basal and exposed to diurnal cyclic temperatures of 23.9 to 35 C in chambers from 24 to 54 weeks of age. Males fed basal diet + NaHCO3 or .43 g NH4Cl were significantly heavier in body weight by 32 to 39 weeks of age than males on basal diet. Males fed the NaHCO3 diet produced significantly more semen in the first 16 weeks than males on basal diet. No differences were found in percent packed sperm value (PSV), percent dead sperm, or percent abnormal sperm between semen of males fed NaHCO3 diet and basal diet. Spermatozoal motility was significantly higher for semen of males fed NaHCO3 or NH4Cl diets during the 32- to 39-week age period.

Age Factors↗
PubMed1984

Carbonic anhydrase activity of the reproductive tract tissues of aged male fowls and its relationship to semen production.

A significant positive correlation was found between the carbonic anhydrase activity of the testes or ductus deferens and the volume of semen, spermatozoa or seminal plasma per collection. No relationship was found between the carbonic anhydrase activity of tissue from the epididymal region and semen production. The intramuscular injection of greater than 25 mg acetazolamide/kg body weight, a known carbonic anhydrase inhibitor, significantly reduced the carbonic anhydrase activity in the testes, epididymides and ductus deferens. As the dose was increased, the carbonic anhydrase activity of the reproductive tract tissues decreased in a linear manner. The reduction in carbonic anhydrase activity was associated with significantly lower volumes of semen, spermatozoa and seminal plasma per collection.

Acetazolamide↗
PubMed1984

The influence of daylength, body weight, and age on the reproductive ability of broiler breeder cockerels.

June-hatched broiler breeder cockerels of two strains were evaluated for reproductive performance in mating pens from 22 to 48 weeks of age. Two light programs with maximum daily daylengths of 15.5 or 16.5 hr were studied. An increase in the light day to 16.5 hr did not significantly affect the male reproductive traits except in number of completed matings and percent packed sperm volume (PSV). The males on 16.5 hr of light had significantly fewer completed matings than did the males on 15.5 hr. Strain 1 males on 16.5 hr produced significantly more spermatozoa at 35 and 40 weeks of age than males on 15.5 hr of light. Male body weights of both strains were significantly lower at 30 weeks of age on the longer daylength. Body weights of cockerels in all treatment groups increased with aging. The range in male body weight markedly influenced the percentage of producing cockerels with aging. During the late egg cycle, the number of producing males increased as body weight increased. The overall mean age of peak in the percentage of males in semen production was 44 weeks of age, which was 7 weeks later than peak egg production. Hatchability was significantly lower for male Strain 2, which had a higher percent PSV and a higher number of attempted matings than did Strain 1. Body weight was significantly correlated with male vent feather-wear at all ages and with the percentage of producing males at 48 weeks of age. The percentage of producing males was correlated with vent feather-wear, evert score, semen volume, and PSV. These results emphasize the importance of body weight selection for optimum breeding flock performance.

Aging↗
PubMed1983

Measurement of CO(2) and H(2)O Vapor Exchange in Spinach Leaf Discs : Effects of Orthophosphate.

A leaf chamber has been designed which allows the measurement of both CO(2) and water vapor exchange in Spinacia oleracea leaf discs. The center of the disc lies within a cylindrical gas chamber and its margins are enclosed within a cavity through which water or various metabolites can be pumped. In saturating light and normal atmospheres, the leaf discs have a relatively low resistance to H(2)O vapor transfer (r(w) = 1.87 seconds per centimeter) and can support high rates of photosynthesis for several hours. The abaxial surface of a disc had a higher resistance to water vapor transfer (r(w) = 3.22 seconds per centimeter) than the adaxial (r(w) = 2.45 seconds per centimeter) despite having a higher stomatal frequency (abaxial, 105/square millimeter; adaxial, 58/square millimeter). In 2% O(2), the discs required an internal concentration of CO(2) of 115 microliters per liter to support one-half of the maximal velocity of apparent photosynthesis (average value, 66 milligrams CO(2) per square decimeter per hour). In 20% O(2), the comparable values are 156 microliters per liter and 56 milligrams CO(2) per square decimeter per hour. In air, apparent photosynthesis saturated at intensities (750 microeinsteins per square meter per second) well below that of daylight but, when the internal CO(2) was raised to 700 to 900 microliters per liter, photosynthesis was not saturated even at daylight intensities (2025 microeinsteins per square meter per second). The distribution of Prussian blue crystals, formed after ferrocyanide feeding, showed that water entered the disc via the vasculature. When 25-minute pulses of orthophosphate were provided in the feeding solution, there were concentration-dependent increases in both r(w) and r(m) leading to inhibition of photosynthesis. The orthophosphate-dependent inhibitions were reversible.

Journal Article↗
PubMed1983

Effects of mannose on photosynthetic gas exchange in spinach leaf discs.

When mannose is provided in the transpiration stream to spinach (Spinacia oleracea) leaf discs, a series of specific and nonspecific changes occur in CO(2) and H(2)O vapor exchange as a function of feeding time. The initial increases in apparent photosynthesis and transpiration are nonspecific effects due to osmotic changes leading to passive stomatal opening. The mannose-specific effects are: (a) time-dependent changes in the CO(2) concentration required for saturation; (b) complex kinetics of the inhibition of CO(2) assimilation dependent on CO(2) and O(2) concentrations and the duration of feeding (high CO(2) and low O(2) lead to rapid inhibitions of photosynthesis); (c) elimination of the capacity of 2% O(2) to stimulate photosynthesis; and (d) oscillations in the CO(2) exchange rate following transitions from 20% to 2% O(2). The mannose-specific effects are reversible by orthophosphate. The mannose-dependent changes in gas exchange are attributed to altered [ATP]/[ADP] ratios.

Journal Article↗
PubMed1979

Events Surrounding the Early Development of Euglena Chloroplasts: 14. Biosynthesis of Cytochrome c-552 in Wild Type and Mutant Cells.

Lack of a suitable assay has thwarted attempts to measure cytochrome c-552 in dark-grown wild type cells of Euglena gracilis var. bacillaris in mutants and in other situations where the concentrations are low. Purification methods are described based on electrofocusing which provide a cytochrome c-552 preparation homogeneous enough to elicit a single reactive antibody in rabbits; this antibody is then used as a specific and sensitive assay for cytochrome c-552. Dark-grown cells of wild type and of mutants O(1)BS, O(2)BX, G(1)BU and P(1)BXL (which make normal sized chloroplasts with abnormal internal structure in the light) have 0.02 to 0.1 x 10(-11) micromoles of cytochrome c-552 per cell, 10 to 150 times less than light-grown cells. Light-grown cells of these mutants and of wild type show a ratio of chlorophyll to cytochrome of about 300 (mole to mole). Cytochrome c-552 is undetectable in dark-grown Y(1)BXD, Y(3)BUD, and W(34)ZUD which cannot carry plastid development beyond the proplastid in light; the light-grown cells of these mutants have levels of cytochrome similar to or lower than dark-grown wild type cells. Cytochrome c-552 is undetectable in light- and dark-grown mutants in which plastid DNA is undetectable (such as Y(2)BUL, W(3)BUL, W(8)BHL, and W(10)BSmL) consistent with the view, but not proving, that this molecule may be coded, at least in part, in plastid DNA. During light-induced chloroplast development in resting cells, cytochrome c-552 formation behaves in all respects like chlorophyll except that the dark-grown cells contain low amounts of the cytochrome c-552 but lack chlorophyll. Thus, both cytochrome c-552 and chlorophyll show the same lag period even when the length is changed by nutritional manipulation; preillumination largely eliminates the lag in the formation of both molecules, cycloheximide and streptomycin both inhibit the biosynthesis of chlorophyll and cytochrome c-552 in the same manner, and the formation of both during chloroplast development is strictly light-dependent. It is shown that chloroplasts isolated from Euglena by methods thought to give intact organelles, lack 95% of the cytochrome c-552; this and the loss of similar molecules may explain why these isolated chloroplasts are not photosynthetically active.

Journal Article↗
PubMed1977

Isolation and some properties of ribulose-1, 5-bisphosphate carboxylase-oxygenase from red kidney bean primary leaves.

Purification of ribulose-1,5-bisphosphate carboxylase from primary leaves of Phaseolus vulgaris var. Red Kidney with ammonium sulfate precipitation, ion exchange chromatography, and gel filtration resulted in the complete loss of detectable oxygenase activity and the retention of a low velocity and a high K(m) form of both the carboxylase and oxygenase. The polyethylene glycol-6000-purified ribulose-1, 5-bisphosphate oxygenase displayed a broad pH optimum (7.9-9.4) and a high K(m) for O(2) and ribulose 1,5-bisphosphate (0.90 mm and 0.25 mm, respectively). Initiation of the oxygenase reaction with protein rather than ribulose 1,5-bisphosphate resulted in reduced activity. The enzymes prepared by the two purification procedures were electrophoretically different.Etiolated primary leaf tissue exhibited low rates of both carboxylase and oxygenase. Similar developmental kinetic activity was observed for both reactions during greening. Photosynthetic (14)CO(2) fixation was inhibited 95% by 100% N(2) gas during the first 24 hours of greening, but the inhibition was rapidly overcome by 48 to 72 hours of light exposure.

Journal Article↗
PubMed1976

Unusual noninfectious granulomas of the lung.

Illustrative cases of pulmonary granulomas with angitis and plasma cell granuloma of the lungs are presented. Experimental evidence suggests that the common pathogenesis of these processes is a cell-mediated immune response. Radiographic findings of these entities--nodules or infiltrates, some with cavities--are non-specific. Effective treatment is available for some of these processes. Lung biopsy as early as possible is recommended.

Adult↗
PubMed1975

Effect of drinking water temperature on broiler performance.

In the first experiment, higher body weight gain and feed comsumption were attained with water at a temperature of 23.9 degrees C. as compared with 35.0 degrees C. No significant differences in feed efficiency due to water temperature were evident. Livability was significantly reduced during brooding for the birds given warm water (35.0 degree C). A significant interaction for body weight gain was observed between the initial ambient air brooding temperatures and water temperatures during the growing period. In the second experiment six water temperatures during brooding to three weeks of age were studied. Body weight gain and feed comsumption were significantly depressed at a drinking water temperature of 40.6 degrees C. as compared with drinking water temperatures between 17.8 degrees C. and 35.0 degrees C. No differences in livability were noted which was in contrast to the results of the first experiment. A drinking water temperature below ambient air temperature is apparently beneficial to the growth of the broiler chick. The placement of the waterers in relation to the brooder stoves could influence water temperature which would affect the growth of broilers.

Acclimatization↗