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T Brody

Publications and source records attributed to T Brody.

At least 37 records · Page 2Linked to original sources
PubMed1987

Evidence for the glycoprotein nature of vitamin K-dependent carboxylase from rat liver.

The ability of the rat liver microsomal vitamin K-dependent carboxylase and microsomal precursors of prothrombin and other vitamin K-dependent proteins to bind to lectin gels has been determined. Under denaturing conditions which dissociate precursor substrates from the carboxylase enzyme, prothrombin precursors and microsomal proteins labeled in gamma-carboxyglutamate residues with [14C]bicarbonate were nearly quantitatively bound to concanavalin A gels. When lentil lectin gels were used, only about one third of these proteins were bound, suggesting a heterogeneity of this glycoprotein pool. Under non-denaturing conditions, both precursor proteins and vitamin K-dependent carboxylase activity were retained on either concanavalin A or lentil lectin gels. These data are consistent with an increase in lectin binding determinants in the precursor-carboxylase complex and are evidence for the glycoprotein nature of this microsomal enzyme.

Animals↗
PubMed1987

Analysis of T-cell subset proliferation at afebrile and febrile temperatures: differential response of Lyt-1+23- lymphocytes to hyperthermia following mitogen and antigen stimulation and its functional consequence on development of cytotoxic lymphocytes.

Poikilotherms are now known to increase their survival by behaviorally induced fevers in response to pathogenic infection. Increased host resistance to viral and bacterial infections has also been noted in homeotherms whose body temperature has been elevated by manipulation of ambient temperature. These observations suggest that fever may increase host resistance by augmenting acquired immunity; thus, this highly conserved response during evolution may provide a survival advantage against environmental pathogens. This possibility has prompted us to investigate the influence of a temperature characteristic of a modest fever in humans (39 degrees C) on T-cell proliferation and function. Our studies revealed that T-cell mitogenesis was enhanced when cultures were incubated at the febrile temperature (39 degrees C). Analysis of T-cell subsets demonstrated that temperature enhanced the mitogenic (Concanavalin A) response of Lyt-1+23- splenocytes; in contrast, hyperthermia was deleterious to lectin-driven proliferation of the Lyt-1-23+ population even in the presence of large quantities of recombinant interleukin-2 (rIL-2). B-cell mitogenesis was invariably inhibited by hyperthermia over a broad range of concentrations of lipopolysaccharide (LPS). Although T-cell mitogenesis was enhanced at the febrile temperature, T-cell proliferation induced by alloantigens or by a murine pathogen, Sendai virus (SV), was diminished at the febrile temperature. Hyperthermia inhibited SV-induced proliferation of Lyt-1+23- lymphocytes, indicating that a febrile temperature can either augment or inhibit T-cell proliferation of the same T-cell subset depending upon the activation signal (i.e., lectin or antigen). Because effector cell development depends upon antigen-induced clonal expansion (proliferation), we evaluated the influence of temperature on primary cytotoxic thymus (T)-derived lymphocyte (CTL) responses against alloantigens and secondary CTL responses against SV under afebrile and febrile conditions. We consistently observed that the induction of alloreactive and virus-specific CTL was diminished in cultures incubated at the elevated temperature, suggesting that a thermosensitive event(s) exists in the progression of CTL derived from either CTL precursors (CTLp) or memory CTL. Furthermore, hyperthermia reduced the number of SV-specific CTL detectable by limiting dilution analysis, suggesting that another event independent of clonal expansion was thermolabile during effector cell development. In view of these results, we suggest that it may be premature to conclude that the observed increase in host resistance induced by a febrile state is mediated by enhanced cell-me

Antigens, Ly↗
PubMed1987

Tissue-specific regulation of renin expression in the mouse.

Increasing biochemical evidence suggests that the renin-angiotensin system may be present in may extrarenal tissues. We have employed the mouse submandibular gland renin complementary DNA (pDD-1D2) and the rat liver angiotensinogen complementary DNA (pRang 3) to demonstrate that renin and angiotensinogen messenger RNAs are expressed in the mouse kidney, submandibular gland, heart, adrenal, brain, and testis. To elucidate the factors that influence local tissue renin-angiotensin expressions, we studied tissue renin messenger RNA and enzymatic levels of male mice in response to sodium depletion and castration. Sodium depletion resulted in increased renin expression in the kidney, heart, and adrenal, but not in the submandibular gland and testis. Castration lowered renin levels in all extrarenal tissues but appeared to increase renin level in the kidney. Taken together, the above data demonstrate tissue-specific regulation of renin expression and imply different functions for the sodium responsive and nonresponsive systems.

Adrenal Glands↗
PubMed1987

A comparative study of the distributions of renin and angiotensinogen messenger ribonucleic acids in rat and mouse tissues.

Previous studies have reported the presence of renin mRNAs in several mouse tissues and angiotensinogen mRNAs in various rat tissues. Clarification as to whether renin and angiotensinogen mRNAs are coexpressed in the same tissues of the same animal species is important for understanding the biology of the tissue renin-angiotensin system. We employed mouse renin cDNA and rat angiotensinogen cDNA to compare tissue distributions of renin and angiotensinogen in RNAs of the rat and mouse. Both cDNA probes readily cross-hybridize with the corresponding mRNA of the other species. Our results demonstrate several patterns of distribution. Renin and angiotensinogen mRNAs are readily detected in kidney and adrenals of both species. In brain and heart, angiotensinogen mRNAs are present in concentrations that far exceed renin mRNA levels in these organs in both species. In mouse and rat livers, angiotensinogen, but not renin, mRNA is demonstrated. In rat testis, only renin mRNA can be detected, whereas in mouse testes both renin and angiotensinogen mRNA are present. In CD-1 male mouse submandibular gland, renin mRNA exists in high concentrations, whereas angiotensinogen mRNA is present in low levels. In contrast, neither renin nor angiotensinogen mRNA could be detected in rat salivary gland. In summary, our study demonstrates the widespread codistribution of renin and angiotensinogen mRNAs in many tissues of both species, allowing for the possibility of local angiotensin production. However, tissue and species differences in these gene expressions also exist. Understanding differential tissue expressions of these genes will provide additional important insight into the biology of the renin-angiotensin system.

Angiotensinogen↗
PubMed1984

Effect of diet and early quantitative feed restriction on the minimum weight requirement for onset of sexual maturity in white rock broiler breeders.

The effect of diet and feed restriction on minimum weight for onset of sexual maturity was studied in White Rock broiler breeders. In the restriction experiment, three groups of birds were subjected to moderate, severe, and very severe quantitative food restriction during the rearing period (19 week target weights: 1900, 1300, and 700 g, respectively). From 20 to 24 weeks body weight was equalized at 2200 g, and from 24 weeks birds were allowed to gain about 150 g/week until first egg. In the diet experiment, two groups of birds were raised under severe quantitative food restriction during the rearing period and then allowed to gain about 150 g/week on a low metabolizable energy/protein (ME/P) ratio diet (25.4% protein, ME/P = 116) and on a high ME/P ratio (14.7% protein, ME/P = 219) until first egg. All birds were killed at first egg. Birds of the three restriction groups entered lay at the same lean body weight and ash and protein content, but at different age, carcass weight, shank length, dry matter, and fat content. Birds of the two diet groups entered lay at the same lean body weight, shank length, and ash content but at different carcass weight, dry matter, and fat content. Considering both experiments together, birds of the different treatment groups entered lay at similar lean body weight and ash content but differed in age, carcass weight, shank length, dry matter, and fat content.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1984

Minimum weight for onset of sexual maturity in female chickens: heritability and phenotypic and genetic correlations with early growth rate.

The heritability of minimum weight for onset of sexual maturity in chickens (WTSXM) and its phenotypic and genetic correlations with early growth rate were studied in a Leghorn (L) layer stock, in two White Rock (WR) broiler stocks, and in the F4, F5, and F6 segregating generations of a White Rock X Leghorn (WR X L) cross. Mean heritability of WTSXM was .38 in the WR populations and .84 in the WR X L cross populations. Mean WTSXM of the various genetic stocks were closely related to their mean early growth rate. The mean phenotypic correlation of WTSXM and early growth rate was .07 in the WR populations but .47 in the WR X L cross populations. Estimates of the genetic correlation of WTSXM with early growth rate were high, and uniform in sign in the WR X L cross populations but smaller in magnitude and variable in sign in the WR populations. The implications of these results with respect to WTSXM as a breeding objective are discussed.

Animals↗
PubMed1984

Intakes of feed and water following restriction in selected and nonselected broilers.

Consumption following a 24-hr withdrawal from feed or water was examined in selected and nonselected broilers from 0 to 10 days of age and in low body weight (LW), high body weight (HW), and HW X LW (F1) progeny from 120 to 132 days of age. In posthatch trials, body weights of feed-restricted (FR) and water-restricted (WR) selected broilers decreased more rapidly than comparable treatments in nonselected broilers. Feed intake of ad libitum control treatments in both genotypes was significantly greater than feed intake of FR and WR treatments. Nonselected birds had a greater ability to compensate for feed deprivation than selected birds, and there appeared to be no differences between genotypes with regard to ability to compensate for water deprivation. The LW birds and HW X LW progeny (F1) had greater ability than HW birds to compensate for both feed and water restriction. Feed consumption on days of water restriction was not as severely reduced as was water consumption on days of feed restriction. It was concluded that water intake is more dependent on the availability of food than is food intake on the availability of water at 120 days in the LW and HW lines.

Animals↗
PubMed1982

Folate oligoglutamate:amino acid transpeptidase.

A new and previously unrecognized enzyme activity folate oligoglutamate:amino acid transpeptidase (folate transpeptidase), was detected in rat liver extracts. This activity involves the exchange of the terminal gamma-glutamyl residue (where PteGlu represents pteroylglutamic acid) of H4PteGlu-gamma-Glu, PteGlu-gamma-Glu, or p-aminobenzoyl-Glu-gamma-Glu for an amino acid such as [14C]glutamic acid, [14C]methionine, [14C]glutamine, or [14C]glycine. In the case of substrates PteGlu2 and [14C]Glu, the product is PteGlu-gamma-[14C]Glu. The enzyme responsible for catalyzing this activity was purified 39,000-fold by precipitation of inactive protein, fractionation on anionic and molecular sieve columns, and chromatography on diaminohexane-Sepharose. The enzyme functions maximally at pH 7.9, shows an absolute requirement for sulfhydryl reductants, and appears to have a molecular weight of 65,000. The function of folate transpeptidase is not known. A second, though much weaker, enzyme activity, tetrahydrofolic acid:amino acid ligase (folate ligase), co-purified with folate transpeptidase through all steps. Folate transpeptidase and the associated folate ligase activity were separated from folate polyglutamate synthetase during the initial steps of the purification procedure.

Acyltransferases↗
PubMed1982

Folate pentaglutamate and folate hexaglutamate mediated one-carbon metabolism.

The proposal that folate polyglutamate cofactors of different chain lengths function differently in metabolism was investigated. We identified the one-carbon units present in rat liver folates within each of the liver folate polyglutamate groups, the folate penta-, hexa-, and heptaglutamates. This identification revealed that at the pentaglutamate level, 5-methyl-H4folate was the major form, accounting for 18% of the total liver folates, with small amounts of H4folate. At the hexaglutamate level, 5-methyl-H4folate and H4folate were major forms, accounting for 17% and 22% of the liver folates, respectively. At the heptaglutamate level, 5-methyl-H4folate occurred in small amounts while H4folate predominated. The rats used here had been fed a diet low in methionine and were exposed to N2O gas. These results are qualitatively similar to those from rat brain [Brody, T., Shin, Y. S., & Stokstad, E. L. R. (1976) J. Neurochem. 27, 409--413] where 5-methyl-H4folate was a major fraction of the folate pentaglutamates but a minor, if detectable, part of the hexa- and heptaglutamates. The folates 5-methyl-H4PteGlu5-7 were metabolically active in the liver, as illustrated by the severe contraction in the amounts of these folates following an injection of methionine. This indicates that "folate-binding proteins" do not prevent 5-methyl-H4folates from entering into one-carbon metabolism.

Animals↗
PubMed1980

Compensatory growth and sexual maturity in broiler females reared under severe food restriction from day of hatching.

1. Compensatory growth and the onset of lay were studied in White Rock broiler females severely restricted in food intake from day of hatching. 2. When changed to feeding ad libitum the restricted birds gained weight rapidly, but stabilised at a mean body weight 500 to 700 g less than that of controls fed ad libitum. Egg production was similar to that of controls. 3. Birds maintained at low mean body weight ( 2 224 g at 42 weeks) by continued restriction did not come into lay. In groups maintained at somewhat higher mean body weights (2 300 to 2 700 g) for period of up to a year, some birds came into lay. 4. Birds fed ad libitum showed accelerated development of comb, ovary and oviduct and weighed 2 300 to 2 700 g between 14 and 15 weeks of age, but did not come into lay until 20.5 weeks of age. 5. These results suggest that a minimum body weight and age may be required for the onset of lay in this strain.

Animals↗
PubMed1976

Subcellular localization of gamma-glutamyl carboxypeptidase and of folates.

The subcellular distributions of glutamyl carboxypeptidase, folate specific activities, and radioactive metabolites of injected [3H] folic acid were studied in rat liver. The specific activity of glutamyl carboxypeptidase in the lysosomal fraction was near or greater than four times that in the other subcellular fractions. The specific activity of folates was highest in the soluble fraction (102 ng folate/mg protein) and lowest in the microsomal fraction (22 ng folate/mg protein). Nuclear, mitochondrial, and lysosomal folates were 95% folate polyglutamates, and microsomal and soluble folates were 85--90% folate polyglutamates. Injected [3H] folic acid was initially concentrated in the microsomal fraction, as measured by 3h cpm per ng folate. Initially, injected [3H] folic acid was found converted to folate penta- and hexaglutamates in all fractions to a similar extent except in the microsomes where the percentage conversion was much less, as measured by the percentage of total 3H cpm determined to be [3H] folate penta- and hexaglutamates. At 24 h, the conversion of [3H] folates to penta- and hexaglutamates in each fraction was less than that found for the endogenous folates. Injected [3H] folic acid after 2h was found to consist of 94% reduced folates in the soluble fraction, 56% in the mitochondrial, 55% in the nuclear, 20% in the lysosomal, and 15% in the microsomal fraction.

Acid Phosphatase↗