Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When Bacillus brevis ATCC 8185 was subjected to nutritional shiftdown from a rich medium to one completely devoid of a nitrogen source, sporulation could be stimulated by the addition of linear gramicidin. Gramicidin-induced sporulation occurred after a considerably longer lag period than the earlier described tyrocidine-induced process (Ristow and Paulus 1982) but involved similar associated biochemical changes, such as extracellular protease production, rapid incorporation of radioactive precursors into RNA, and dipicolinate synthesis. The increased incorporation of [3H]leucine into tyrocidine was a characteristic element in gramicidin-induced sporulation, not being observed when spore formation was accelerated by limited nitrogen supplementation. Nitrogen supplementation (0.02-0.01% nutrient broth) caused a slow and gradual increase in dipicolinate production, in contrast to the sudden, rapid rise of dipicolinate synthesis provoked by the addition of gramicidin or tyrocidine. The induction of sporulation by gramicidin occurred at very low peptide concentrations (0.03 microM), which also brought about an acute depletion of intracellular ATP. In sporulation accelerated by nutrient broth, no depression of ATP level was observed and nonionophoric analogues of gramicidin were unable to substitute for gramicidin in inducing sporulation.
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PMID:Effect of linear gramicidin on sporulation and intracellular ATP pools of Bacillus brevis. 242 Mar 1

The present longitudinal study was designed to characterize immunosuppression during acute Plasmodium falciparum infection, during the treatment and up to 1 month after the acute stage. The proliferative responses of blood mononuclear cells (BMNC) isolated from non-immune and semi-immune malaria patients and controls to mitogens and two Plasmodium-derived stimulators (merozoites, Meroz, and soluble purified antigen, SPag) and non-related antigens were measured by [3H]thymidine incorporation. BMNC isolated before treatment (day 0) from the non-immune patients did not respond to Meroz, whereas those from controls showed a significantly higher response. The SPag responses were also low in BMNC isolated on day 0 and increased in both the non-immune and the semi-immune patients during the observation period. These findings indicate that during malaria there is a depression of the parasite-specific proliferative response. The subset composition of BMNC isolated from non-immune patients was studied in a FACS analyser. The mean cell volumes of both Leu 2+ and Leu 3+ cells were increased during the acute phase of the infection, indicating that malaria infection results in activation of both T-helper and T-suppressor cells. There was no overall reduction of the response to mitogens on day 0. However, 3 days after initiation of the treatment the mitogen response was decreased. This finding indicates that it is important to distinguish between the effects of malaria infection and of drug treatment.
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PMID:Suppression of parasite-specific response in Plasmodium falciparum malaria. A longitudinal study of blood mononuclear cell proliferation and subset composition. 242 16

Treatment of mice with the interferon inducer polyriboinosinic acid X polyribocytidylic acid [poly(IC)] results in the depression of several hepatic proteins. In this study we examined synthesis and degradation of the proteins of liver cell organelles in mice treated with poly(IC). Effects on synthesis were determined by using [14C]- and L-[3H]leucine incorporation into control and poly(IC)-treated mice, respectively. At selected times after poly(IC) treatment the 3H/14C ratio was established for preparations of nuclei, mitochondria, lysosomes, smooth endoplasmic reticulum, rough endoplasmic reticulum, and 105,000g supernatant (cytosol). Time-dependent alterations in de novo protein synthesis were greatest in lysosomal and rough endoplasmic reticular fractions; both were depressed 9 h after treatment. The effects of poly(IC) on protein degradation were determined with [14C]bicarbonate. Poly(IC) treatment decreased the time required for disappearance of 50% of 14C-labeled protein (t1/2) of smooth and rough endoplasmic reticula. Examination of endoplasmic reticulum marker enzymes showed depression of cytochromes P-450 and b5 from 9 h onward after poly(IC) administration. Tyrosine aminotransferase activity was elevated 6 h after treatment with poly(IC), and then depressed after 9 h. The other organelle marker enzymes were not affected significantly. We conclude that poly(IC) decreases the content of proteins of the hepatic endoplasmic reticulum, including certain cytochrome P-450 isozymes, by decreasing rates of protein synthesis and increasing rates of protein degradation.
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PMID:Depression of cytochrome P-450 and alterations of protein metabolism in mice treated with the interferon inducer polyriboinosinic acid X polyribocytidylic acid. 243 May 24

We have investigated the effects of granulocyte-macrophage (GM) CSF on two biochemical responses thought to play internal signaling roles in the neutrophils, namely the increase in the concentration of free calcium and the changes in the internal pH. The changes in the right-angle light scatter of the cell suspensions were also examined. GM-CSF was found not to affect the resting levels of calcium or the internal pH of the cells. However, pre-incubation of the neutrophils with the growth factor resulted in an increase in the magnitude of the calcium transients that follow the stimulation of the cells with chemotactic factors as well as a profound depression of the cell alkalinization that is induced by fMet-Leu-Phe, leukotriene B4, and platelet-activating factor, as well as by phorbol esters. The rapid cytoplasmic acidification elicited by these agents was apparently magnified. GM-CSF did not directly affect the Na+/H+ antiport as GM-CSF-treated cells were as capable as untreated cells of recovering from an acid load. The right-angle light scatter responses of the cells to the chemotactic factors were found not to be affected by GM-CSF. These results provide an initial description of the effects of GM-CSF on the cellular physiology of the neutrophils and insights into the mechanism of action of this factor as well as into the excitation-response coupling sequence activated by chemotactic factors.
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PMID:Granulocyte-macrophage colony-stimulating factor modulates the excitation-response coupling sequence in human neutrophils. 245 91

Nitrous oxide (N2O), an anesthetic gas, has been implicated as a human teratogen. The mechanism for its developmental toxicant effects is not known but may involve depression of embryonic macromolecular synthesis caused by alterations in precursor concentrations. Such changes might be caused by decreased folate levels. Pregnant rats were exposed to 50% N2O for 24 hours on day 10 of gestation; this is not an anesthetic dose. Embryos were removed immediately after exposure and grown in a rodent whole embryo culture system for 4 hours in medium containing radiolabeled precursors for RNA or protein. Exposure to N2O decreased embryonic DNA and RNA contents but did not alter number of somite pairs or protein content. Such treatment also decreased incorporation of radiolabeled uridine into acid-precipitable RNA. There was no difference between control and treated embryos in the incorporation of radiolabeled leucine into protein. There were also no differences between control and exposed embryos in the level of acid-soluble purines. The lower DNA and RNA contents in N2O-treated embryos are apparently not the result of decreased levels of adenine or guanine.
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PMID:Effect of nitrous oxide on embryonic macromolecular synthesis and purine levels. 245 30

1. Repetitive stimulation (10-20 Hz, 0.5-5 s duration) of the preganglionic nerves to ganglia on the surface of the urinary bladder of the cat produced a prolonged inhibition (duration, 30-65 s) of the postganglionic action potentials, elicited by low-frequency stimulation (0.25-1 Hz) of another preganglionic nerve to the same ganglion. 2. Intra-arterial administration of naloxone, an opiate antagonist (20-50 micrograms/kg), reduced the magnitude and duration of this heterosynaptic inhibition and also blocked the depression of ganglionic transmission elicited by the intra-arterial administration of leucine-enkephalin (0.1-10 micrograms/kg). 3. Naloxone did not alter adrenergic inhibition elicited by repetitive stimulation of the hypogastric nerve or exogenous noradrenaline. Naloxone did not alter the postganglionic firing elicited by single stimuli or trains of low-frequency (1-3 Hz) stimuli to the preganglionic nerves. 4. Heterosynaptic inhibition was not altered by the administration of antagonists for alpha-adrenergic (dihydroergotamine, prazosin, yohimbine), muscarinic (atropine), purinergic (theophylline) or GABAergic (picrotoxin) receptors. 5. A delta-selective opiate receptor agonist, DSLET (D-Ser2-leucine-enkephalin-Thr), inhibited parasympathetic ganglionic transmission in low doses (mean threshold dose, 0.02 microgram/kg, I.A.), whereas a mu-opiate receptor agonist, morphine sulphate, produced only a small depression in larger doses (mean threshold dose, 100 micrograms/kg, I.A.). Ethylketocyclazocine, which has an affinity for kappa-receptors did not alter transmission in relatively large doses (1 mg/kg, I.A.). 6. These findings coupled with previous immunocytochemical demonstrations of leucine-enkephalin-like immunoreactivity in preganglionic nerve terminals in bladder ganglia suggest that opioid peptides released endogenously from preganglionic nerves are involved in delta-receptor-mediated inhibitory mechanisms at cholinergic synapses in bladder ganglia.
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PMID:Enkephalinergic inhibition in parasympathetic ganglia of the urinary bladder of the cat. 260 Aug 44

This study was undertaken to determine whether regular endurance running, of the type known to attenuate glucocorticoid-induced muscle atrophy, produces a reversal of the glucocorticoid-mediated suppression of myosin heavy chain (MHC) synthesis. Female rats were arbitrarily assigned to one of four groups. There were two sedentary groups that received either a vehicle (1% aqueous carboxymethyl cellulose) or cortisol acetate (100 mg/kg body wt) for 11 consecutive days and two exercise (treadmill running 29 m/min, 90 min/day, for 11 consecutive days) groups that received the activity simultaneously with either vehicle or steroid treatments. Protein synthesis measurements were performed by constant infusion of [3H]leucine. Fractional synthesis rates of MHC were determined from the leucyl-tRNA precursor pool, which was similar in all groups (range 2.85 +/- 0.32 to 3.51 +/- 0.43 dpm/pmol). Exercise prevented 30% of the plantaris muscle mass loss as the result of cortisol acetate treatment. MHC synthesis rates (%/day) in plantaris muscles of sedentary animals were reduced by glucocorticoid treatment to 65% (6.2/9.5) of the vehicle-treated group. Exercise did not alter this depression of MHC synthesis. The combination of exercise and glucocorticoid treatment reduced the calculated MHC breakdown rate (%/day) to 80% (-8.0/-10.1) of the rate resulting from hormone treatment alone and 60% (-8.0/-13.3) of the rate resulting from exercise alone. These results show that endurance exercise does not reverse the glucocorticoid inhibition of MHC synthesis in muscle but may act through reducing MHC breakdown.
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PMID:Myosin heavy chain turnover and glucocorticoid deterrence by exercise in muscle. 260 37

The depression of milk protein percentages for cows fed high fat diets in early lactation is a major problem facing the dairy industry. In order to describe more fully the mechanism involved, data involved 97 cows observations were summarized. Cows were fed diets containing corn-soybean meal or additional fat in the form of whole oilseeds as the main ingredients in the concentrate mix. Blood samples from the tail artery and subcutaneous abdominal vein were taken approximately 6- to 8-wk postpartum for amino acid analyses. Production of milk during the week of blood sampling was increased (36.9 and 39.6 kg/d) approximately 7.3% but milk protein percentages (2.91 and 2.79) were reduced for cows fed added fat. Intake of DM (21.1 and 21.4 kg/d) and BW (605 and 608 kg) were similar. Uptake of amino acids by the mammary gland, as measured by arteriovenous differences, was numerically lower for all essential amino acids and significantly reduced for histidine, isoleucine, leucine, phenylalanine, threonine, valine, and total essential amino acids for cows fed added fat. It is proposed that added fat inhibits somatotropin release from the anterior pituitary, thereby reducing mammary gland uptake of amino acids because of the role of somatotropin in aiding amino acid uptake. Administration of exogenous somatotropin with added fat diets may alleviate milk protein depression associated with such diets.
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PMID:Model to describe and alleviate milk protein depression in early lactation dairy cows fed a high fat diet. 262 49

The three-dimensional structure of the native unliganded form of the Leu/Ile/Val-binding protein (Mr = 36,700), an essential component of the high-affinity active transport system for the branched aliphatic amino acids in Escherichia coli, has been determined and further refined to a crystallographic R-factor of 0.17 at 2.4 A resolution. The entire structure consists of 2710 non-hydrogen atoms from the complete sequence of 344 residues and 121 ordered water molecules. Bond lengths and angle distances in the refined model have root-mean-square deviations from ideal values of 0.05 A and 0.10 A, respectively. The overall shape of the protein is a prolate ellipsoid with dimensions of 35 A x 40 A x 70 A. The protein consists of two distinct globular domains linked by three short peptide segments which, though widely separated in the sequence, are proximal in the tertiary structure and form the base of the deep cleft between the two domains. Although each domain is built from polypeptide segments located in both the amino (N) and the carboxy (C) terminal halves, both domains exhibit very similar supersecondary structures, consisting of a central beta-sheet of seven strands flanked on either side by two or three helices. The two domains are far apart from each other, leaving the cleft wide open by about 18 A. The cleft has a depth of about 15 A and a base of about 14 A x 16 A. Refining independently the structure of native Leu/Ile/Val-binding protein crystals soaked in a solution containing L-leucine at 2.8 A resolution (R-factor = 0.15), we have been able to locate and characterize an initial, major portion of the substrate-binding site of the Leu/Ile/Val-binding protein. The binding of the L-leucine substrate does not alter the native crystal structure, and the L-leucine is lodged in a crevice on the wall of the N-domain, which is in the inter-domain cleft. The L-leucine is held in place primarily by hydrogen-bonding of its alpha-ammonium and alpha-carboxylate groups with main-chain peptide units and hydroxyl side-chain groups; there are no salt-linkages. The charges on the leucine zwitterion are stabilized by hydrogen-bond dipoles. The side-chain of the L-leucine substrate lies in a depression lined with non-polar residues, including Leu77, which confers specificity to the site by stacking with the side-chain of the leucine substrate.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Periplasmic binding protein structure and function. Refined X-ray structures of the leucine/isoleucine/valine-binding protein and its complex with leucine. 264 82

Cellular protein degradation during and following hyperthermia should be altered due to increased enzymatic activity at elevated temperatures, inhibition of protein synthesis, and denaturation of proteins. We have previously demonstrated by differential scanning calorimetry that approximately 1-2% of total CHL V79 cellular protein denatures during a 10- to 15-min exposure to 43 degrees C (J. E. Lepock et al., J. Cell. Physiol. 137, 14-24 (1988)). Proteolysis was measured during and after exposure to 43 degrees C. The decay curves of the degradation of [3H]Leu-labeled proteins are fit well by a double exponential; however, each component is the sum of the decay curves of a large number of proteins, probably with a distribution of rates of degradation. At 37 degrees C a fast-decaying component (T1/2 congruent to 1.3 h), representing short-term proteins, and a slow-decaying component (T1/2 congruent to 50 h), representing long-term proteins, are observed. At 43 degrees C the rate of degradation of the fast-decaying component is stimulated three- to fivefold (to T1/2 = 0.27-0.45 h). After return to 37 degrees C, the rate of degradation of the slow-decaying component is depressed twofold (to T1/2 = 109-141 h). The period of depression is dose dependent (i.e., time at 43 degrees C) and recovers at approximately the same time as resumption of protein synthesis and growth. Overall stimulation of degradation lasts for approximately 15 min at 43 degrees C and, coupled with an inhibition of synthesis, leads to the loss of at least a small percentage of total cellular protein. It is likely that the initial stimulated degradation is in part due to increased substrate in the form of denatured protein, further supporting the denaturation of proteins during hyperthermia.
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PMID:Protein degradation in CHL V79 cells during and after exposure to 43 degrees C. 275 11


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