Conditioned media prepared from umbilical cord (UC) segments or endothelial cells (EC) contain colony stimulating activity, Both UCCM and ECCM were partially purified by DEAE-Sepharose and ACA44 gel filtration chromatography. The molecular weights were estimated as 25,000 and 31,000 for UC-CSF and EC-CSF, respectively. UC-CSF was further fractionated by Con A Sepharose, IEF and HPLC on a hydrophobic phenyl column. The highly purified CSF stimulates human macrophage and granulocyte colony formation, indicating it is GM-CSF in nature. Characterization studies have revealed that both CSFs are heat stable at 60°C for 30 min. They are sensitive to digestion by protease and to periodate oxidation but are stable to treatment with sulfhydryl reagents. The synthesis of CSF in endothelial cells is inhibited by actinomycin D, cycloheximide and puromycin, indicating that protein and RNA synthesis are required for CSF production. Among the mitogens tested, only LPS exhibited stimulatory activity on the production of CSF. Metabolic modulators such as dibutyryl cAMP, isobutylmethylxanthine, PGE2 and lactoferrin inhibit CSF production, while PGF2 enhances CSF production.

A Differentiation Factor (DF) was purified from rat lung conditioned medium by a four-steps procedure. The DF has a molecular weight of 27000, and an isoelectric point of 4.70. Although DF is stable up to 60°C, it is sensitive to digestion by trypsin, chymotrypsin and subtilisin. DF forms granulocyte colonies in soft agar. Studies using anti-NRK CSF antibody demonstrated that DF is distinct from GM-CSF.

A modified ascending thin layer chromatographic technique has been developed which resolves the major phospholipid and neutral lipid classes of five common fluids and tissues. A one-half milliliter sample is extracted with n-butanol:diisopropylether (40:60 by volume, cholesteryl acetate = 100 ng/ul) for thirty minutes and the organic phase is spotted onto a thin layer chromatography plate and carried through three successive chromatographic developments. The lipids are then visualized either by charring with ammonium bisulfate or staining with phosphomolybdic acid. The use of cholesteryl acetate as an internal standard enables quantitation of the phospholipids and neutral lipid classes. This method may be a very valuable, new technique for research and clinical laboratories.

Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed …

A method for purification and radiolabelling phosphoglucose isomerase was devised in order to develop a sensitive quantitative radioimmunoassay for the detection of the enzyme irrespective of its catalytic activity. For four genetic variants of PGI no difference in the molecular specific activity was observed. In one variant (PGI-Denton), liver and heart tissue extracts, and in mature erythrocytes (as compared to normal erythrocytes), a decreased molecular specific activity was observed which initially may imply that these samples contain cross-reactive material which is not catalytically active.

The temperature-dependent catalytic activity of rat liver 3-hydroxy-3 -methylglutaryl coenzyme A reductase (HMG-CoA reductase) displays the nonlinear Arrhenius behavior characteristic of many membrane-bound enzymes. A two-conformer equilibrium model has been developed to characterize this behavior. In the model, HMG-CoA reductase undergoes a conformational change from a low specific activity to a high specific activity form. This conformation change is apparently driven by a temperature-dependent phase transition of the membrane lipids. It has been found that this model accurately describes the data from diets including rat chow, low-fat, high-carbohydrate, and diets supplemented with fat, cholesterol or cholestyramine. The effects characterized by the model are consistent with the regulation of HMG-CoA reductase by enzyme-lipid interactions.

Two aspects of the biological activity of N-nitrosamines were studied. First, the effect of ascorbate on the mutagenicity of N-nitrosopiperidines was studied in the Ames Salmanella/ mammalian microsome mutagenicity test. The addition of ascorbate significantly enhanced the mutagenicity of these compounds. This enhancement was selective for N-nitrosamines suggesting a possible role of ascorbate in N-nitrosamine induced carcinogenicity. Second, the technique of velocity sedimentation in alkaline sucrose density gradients was applied to the detection of N-nitrosamine induced DNA damage in Balb/c 3T3 cells. This technique detected N-nitrosamine induced DNA damage when the cells were made permeable before treatment. This technique compares favorably with other test systems used to evaluate N-nitrosamines and should be useful in further studies of N-nitrosamines.

Cytoplasmic 15-hydroxyprostaglandin dehydrogenase from swine kidney was purified to specific activity of 1.2 U per mg protein, by chromatographic techniques. Native molecular weight of enzyme was estimated at 45,000. Enzyme was inhibited by sulfhydryls, diuretics, and various fatty acids. Substrate studies indicated NAD+ specificity and ability to catabolize prostaglandins, except prostaglandin B and thromboxane B. Initial velocity studies gave intersecting plots conforming to a sequential mechanism. 15-keto-prostaglandin exhibited linear noncompetitive production inhibition with respect to either prostaglandin or NAD+; NAD yielded linear competitive production inhibition with respect to NADH. Results, and those of dead-end inhibition and alternated substrate studies, are consistent with an ordered Bi-Bi mechanism: NAD+ is added first, then prostaglandin; then 15-keto-rostaglandin is released, then NADH.

Male Fischer rats (n=43) were used in a diet-diet/ exercise design to investigate the apparent protein sparing effects of exercise. The animals were divided into five groups: INITIAL (baseline), SEDENTARY (control), DIET, DIET/EXERCISE, and EXERCISE. Carcasses were analyzed for body composition, the blood for plasma alanine concentration and the urine for urea nitrogen concentration. The results showed no significant differences between groups in urinary urea nitrogen, plasma alanine, body weight, or carcass weights. The EXERCISE group had a significant increase in percent protein and a significant decrease in percent fat and grams of fat when compared to all other groups (p <.05).

Calcium/phospholipid-dependent protein kinase (PKC) was partially purified from P1798 lymphosarcoma. Phospholipid-dependence was specific for phosphatidylserine. PKC phosphorylated Histone 1, with an apparent K_m of 14.1 μM. Chlorpromazine, a lipid-binding drug, inhibited PKC activity by 100%. Further studies were undertaken to establish analytical conditions which could be applied to the study of PKC in intact cells. The conditions included (1) determining optimum cell concentration for measuring PKC activity, (2) recovering PKC into the soluble fraction of cell extracts, (3) evaluating calcium and phospholipid requirements of PKC in this fraction, and (4) inhibiting PKC in this fraction. Final studies involved treatment of intact cells with potential activators. Both phytohaemagglutinin and a phorbol ester increased PKC activation.

Huian plasma high-density lipoprotein (HDL) were isolated by a procedure employing polyanion precipitation and column chromatography. Lipid and protein composition of the HDL isolated by this method was found to be similar to another HDL preparation isolated by ultracentrifugation. However, minor differences were noted, including a higher phospholipid and apoproteinE content and lower triglyceride content of the HDL isolated by column chromatography. Four subfraction of HDL were obtained following chromatography on an anion exchange column. The subfraction four had the highest esterified to free cholesterol ratio, the second highest phospholipid to unesterified cholesterol, and the lowest molecular weight. In addition it was consistently coincided with lecithin: cholesterol acyltransferase (LCAT) activity and found to be the best substrate for the enzyme.

Recent studies have shown that the Sudden Infant Death Syndrome (SIDS) is related to abnormal control of respiration (Ischemic degeneration of the brainstem may play an important role in altered respiratory control leading to death). In our studies we have examined brainstem ganglioside compositions in samples derived from SIDS victims and appropriate controls. Gangliosides are acidic glycosphingolipids that contain sialic acid. The high concentration of gangliosides in the central nervous system (CNS) implies that these lipids play an important role in CNS function. Some studies have indicated that gangliosides may function as receptor site determinants or modifiers, and in neural transmission. In our studies we used the Tettamanti, et al methodology to extract gangliosides, and High Performance Thin Layer Chromatography (HPTLC) and laser densitometry techniques for ganglioside analysis. The results of these analyses are being employed to establish lipid profile patterns to determine if there are significant variations in these lipid patterns between SIDS and control groups.

Ascaris suum NAD-malic enzyme catalyzes the decarboxylation of oxalacetate and reduction of pyruvate. Thus, the present classification (E.C. 1.1.1.39) for this enzyme should be changed to E.C. 1.1.1.38. In the absence of nucleotide, both the chicken liver NADP-malic enzyme and Ascaris suum NAD-malic enzymes catalyze the decarboxylation of oxalacetate. A study of the pH dependence of kinetic parameters for oxalacetate decarboxylation and pyruvate reduction was carried out for the NAD(P)-malic enzyme with Mg^2+ and Mn^2+ in the presence and absence of nucleotide. In all cases, an enzyme residue is required in its protonated form for reaction while for oxalacetate decarboxylation the β-carboxyl of oxalacetate is required unprotonated. Of a number of inhibitory binding analogs of malate tested, oxalate is the tightest binding inhibitor for Ascaris suum enzyme.

Two swine kidney proteins (PI 4.8 and 5.8) both possessing 9-prostaglandin ketoreductase (9-PGKR) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) activities were purified to homogeneity. Purification increased specific activities in parallel. Molecular weight, subunit size, amino acid composition, coenzyme and substrate specificity and antigenicity of both proteins were similar. Gel filtration and SDS-polyacrylamide gel electrophoresis molecular weights of 29,500 and 29,000, respectively, suggested a single subunit. Although a variety of prostaglandins served as substrates, the best for 15-PGDH was PGB, while PGA_1-GSH showed the lowest Km for 9-PGKR. Rabbit antibody against the PI 5.8 protein crossreacted with both purified renal enzymes and with extracts from rat spleen, lung, heart, aorta, and liver.

The objectives of these investigations were (1) the purification of MG reductase from sheep liver and (2) studies of some of its characteristics. MG reductase was purified 40 fold and showed a single band on SDS-PAGE. Molecular weight estimations with SDS-PAGE showed a molecular weight of 44,000; although gel filtration with Sephadex G-150 gave a molecular weight of 87,000 indicating that the enzyme might be a dimer. The Km for MG is 1.42 mM and for NADH it is 0.04 mM. The pH optimum for the purified enzyme is pH 7.0. Isoelectric focusing experiments showed a pI of 9.3. In vivo experiments involving rats treated with 3,3',5-triiodothyronine (T_3) and 6-n-propyl-2-thiouracil (PTU) indicated that MG reductase was depressed by T_3 and elevated by PTU.

Intracellular levels of NAD are of renewed interest in clinical and basic science research due to the new discovery of enzymes which utilize NAD as a substrate. Microtiter assays for the determination of NAD, NADP and protein were developed as modifications of previously published methods. The resulting assays are simple, cost effective and sensitive. An improved method of isolating lymphocytes was also developed. The resultant procedure requires one hour and removes greater than 99.9% of the platelets. Lymphocyte pools were stabilized with the addition of ADP-ribosyltransferase inhibitors and a modified extraction procedure. These studies have led to the development of a method for evaluation of NAD in human lymphocytes that is sensitive, selective and suitable for automation.

Enzymatic and lipid transfer reactions involved in reverse cholesterol transport were studied in HDL deficient plasma systems. Fasting plasma samples were obtained from control and cholesterol fed guinea pigs as well as from a fish eye disease patient and were used to localize the enzyme LCAT among plasma lipoproteins (VLDL, LDL, and HDL). In both guinea pig and fish eye disease patient plasma, the LCAT activity was found in association with the HDL type particles. Cholesterol feeding in guinea pigs altered the properties of lipoprotein substrates for LCAT resulting in some changes, specifically: 1) decreased fractional rate of plasma cholesterol esterification and, 2) lower transfer of free cholesterol (FC) and esterified cholesterol (CE) within the lipoprotein fractions.

ADP-ribose polymer metabolism has been studied in human cells derived from a patient with Glutamyl Ribose Phosphate Storage Disease (GRPSD) and in mouse C3H1OT1/2 cells following oxidative stress induced by hydrogen peroxide (H202 ). It has been postulated that GRPSD resulted from an abnormality in ADP-ribose polymer metabolism. This study has shown that these cells exhibit reduced poly(ADP ribose) polymerase activity which is proposed to result from modification of the enzyme with ribose phosphate groups. The modification in the polymerase is proposed to be secondary to a defect in either ADP-ribosyl proteinlyase or an overproduction of a cellular phosphodiesterase. The metabolism of ADP-ribose polymers was rapidly altered by H202 and there were independent effects on adenine nucleotide pools. The results suggest that ADP-ribose polymer metabolism is involved in cellular defenses to oxidative stress.

This study demonstrates the presence of protein kinase C activity in both cytosolic and membrane fractions of bovine lens epithelial cells in culture. Protein kinase C activity is similar in normal and hyperglycemic cells. Furthermore, the ability of the enzyme to translocate from the cytosol to the membrane following phorbol ester treatment is unimpeded by hyperglycemic conditions. Moreover, protein kinase C activation had no effect on myoinositol uptake either in normal cells or in cells exposed to hyperglycemic conditions.

A description of the nature of the transition state structure for phosphoryl transfer in the cAPK reaction requires a measurement of the primary 180 isotope effect at the serine hydroxyl acceptor. Since it is difficult to obtain primary 180 isotope effect directly, the 15N/1 4N ratio of the a-amine of the C-terminal glycine in the peptide Leu Arg-Lys-Ala-Ser-Leu-Gly (when serine is phosphorylated) was used to represent on the phosphorylation at serine. 15N Glycine, ' 4N-Glycine and 180 serine were synthesized and used to synthesize two peptides, one containing 1 80-serine/' 5 N glycine and second 1 60-serine/1 4N-glycine. Methods were developed for hydrolyzing the peptides and quantitatively isolating glycine. Partitioning results suggest that catalytic rate was slow compare to substrate dissociation. The 180 primary isotope effect will be determined in the near future using the method developed herein.

Two plaque-pure phage lambda clones designated as λhtX-l and λhtX-2 that hybridized to unfractionated bovine liver tRNA were isolated from a human X chromosome-specific library. The λDNAs were characterized by restriction mapping and Southern blot hybridization techniques. The human DNA segment in λhtX-l contains five or more presumptive tRNA genes and at least one Alu family member. The 19-kilobase human DNA insert in λhtX-2 contains two or more presumptive tRNA genes and at least three Alu family members. Another human genomic clone designated λhVKV7 hybridized to mammalian valine tRNA IAC. The clone was characterized by physical mapping and Southern blot hybridization techniques. The 18.5-kilobase human DNA fragment in λhVKV7 contains a cluster of three tRNA genes and at least nine Alu family members.

Glyoxylase II (Glo II, E.C. 3.1.2.6) catalyzes the hydrolysis of S-D-Lactoylglutathione (SLG) to D-Lactate and glutathione. This is the rate limiting step in the conversion of methylglyoxal to D-Lactate. The purpose of the present study was to determine whether or not a relationship exists between some naturally occuring metabolites and in vivo modulation of Glo II. We have observed a non-competitive inhibition (~ 45%) of Glo II in crude preparation of rat liver by GTP (0.3 mM). A factor (apparently protein),devoid of Glo II,when reconstituted with the purified Glo II, enhanced Glo II activity. This coordinate activation and inhibition of Glo II suggest a mechanism whereby SLG levels can be modulated in vivo.

Tyrosine tRNA was isolated from bovine liver and its nucleotide sequence was determined using in vitro 32p_ labeling techniques. Several important structural features of the tRNA are: the presence of gal-Q in the first position of the anticodon, acp3U at position 20, and a pair of adjacent N,N-dimethylguanosines (residues 26 and 27). A human DNA fragment harbored in a lambda phage clone was isolated, and restriction enzyme analysis revealed the presence of three tRNA genes in a 6.0-kb BamHI subfragment. Portions of the 6.0-kb DNA fragment containing the tRNA genes were sequenced by the method of Maxam and Gilbert and analyzed for transcriptional activity in vitro using homologous cytoplasmic extracts. A threonine tRNAUGU gene exhibited high transcriptional activity dependent on its 5'- flanking sequence. The enhanced transcription is not completely inhibited by alpha-amanitin. The value of studying tRNA structure in concert with the cognate tRNA. genes is discussed.

Two different cloned human DNA segments encompassing transfer RNA gene and pseudogene clusters have been isolated from a human gene library harbored in bacteriophage lambda Charon 4-A. One clone (designated as λhVal7) encompassing a 20.5-kilobase (Kb) human DNA insert was found to contain a valine transfer RNA_AAC gene and several Alu-like elements by Southern blot hybridization analysis and DNA sequencing with the dideoxyribonucleotide chain-termination method in the bacteriophage M13mp19 vector. Another lambda clone (designated as λhLeu8) encompassing a 14.3-Kb segment of human DNA was found to contain a methionine elongator transfer RNA_CAT pseudogene and other as yet unidentified transfer RNA pseudogenes.