scholarly journals A Cytochemical Study on the Pancreas of the Guinea Pig

1960 ◽  
Vol 7 (4) ◽  
pp. 631-644 ◽  
Author(s):  
Philip Siekevitz ◽  
George E. Palade
Keyword(s):  
Molecular Structure ◽  
Guinea Pig ◽  
Incubation Medium ◽  
Sedimentation Coefficient ◽  
Dry Weight ◽  
Analytical Ultracentrifuge ◽  
Cytochemical Study ◽  
Low Concentrations ◽  
Proteolytic Activities ◽  
High Concentrations

Ribonucleoprotein (RNP)1 particles isolated by DOC treatment from pancreatic microsomes have a RNA content of 35 to 45 per cent of their dry weight. In the analytical ultracentrifuge about 85 per cent of the material has a sedimentation coefficient of ∼85 S. These particles contain amylase, RNase, and trypsin-activatable proteolytic activities which cannot be washed off or detached by incubation in 0.44 M sucrose. The enzymes are released, however, by incubation in the presence of low concentrations of ATP, PP, or EDTA, and high concentrations of IP and AMP. At the same time, and at the same concentrations, ∼80 per cent of the RNA and ∼25 per cent of the protein of the particles becomes also non-sedimentable. The simultaneous addition of Mg++ to the incubation medium prevents these losses. This finding, together with the observation that all the Mg++ of the particles is released by the same agents, makes it likely that Mg++ holds the particles together, and that its removal by the chelators used causes the particles to disintegrate. These findings are discussed in relation to the molecular structure of the RNP particles.

scholarly journals The loss of rapidly labelled ribonucleic acid from isolated HeLa cell nuclei

1969 ◽  
Vol 112 (1) ◽  
pp. 71-79 ◽  
Author(s):  
J. W. Watts
Keyword(s):  
Hela Cell ◽  
Incubation Medium ◽  
Sedimentation Coefficient ◽  
Cell Nuclei ◽  
Isolated Nuclei ◽  
Bivalent Cations ◽  
Low Concentrations ◽  
Nuclear Rna ◽  
And Diffusion

1. The loss of nucleic acids and protein from isolated HeLa-cell nuclei was studied. During 4hr. incubation at 37° DNA was conserved, but appreciable amounts of RNA and protein were lost. 2. Two classes of nuclear RNA were distinguished: at least 75% of the RNA was lost from the nuclei relatively slowly through degradation to acid-soluble fragments; the rest of the RNA was lost much more rapidly, not only through degradation to acid-soluble fragments but also through diffusion of RNA out of the nuclei into the incubation medium. 3. The RNA that was preferentially lost was the fraction of nuclear RNA that was rapidly labelled when intact HeLa cells were grown in a medium containing radioactive precursors of RNA. 4. The RNA appearing in the incubation medium was apparently partially degraded and had a sedimentation coefficient of about that of transfer RNA. 5. Both the degradation of RNA and the loss of RNA from the nuclei were sensitive to bivalent cations. Low concentrations of Mg2+ and Mn2+ greatly increased the rate of degradation of the rapidly labelled RNA to acid-soluble fragments, and produced a corresponding decrease in the amount of RNA diffusing into the medium. At higher concentrations they suppressed both degradation and diffusion of RNA. The cations Ca2+, Cu2+, Zn2+ and Ni2+ all progressively inhibited both forms of loss of RNA. 6. Salts of univalent cations produced appreciable effects only at ionic strengths of about 0·2, when degradation to acid-soluble fragments was preferentially inhibited. 7. Both ADP and ATP inhibited loss of RNA at about 30mm. 8. It was concluded that the diffusion of rapidly labelled RNA out of the isolated nuclei was not related to the movement of RNA from nucleus to cytoplasm in vivo, but reflected the ease with which the rapidly labelled RNA detached from the chromatin and the permeability of the membranes of isolated nuclei.

INCORPORATION OF INORGANIC P32INTO PHOSPHOLIPIDS OF BRAIN SLICES: EFFECT OF CERTAIN TRANQUILLIZING DRUGS

1963 ◽  
Vol 41 (1) ◽  
pp. 1155-1162 ◽  
Author(s):  
W. L. Magee ◽  
R. J. Rossiter
Keyword(s):  
Methylene Blue ◽  
Guinea Pig ◽  
Aerobic Glycolysis ◽  
Brain Slices ◽  
Inorganic P ◽  
Pig Brain ◽  
Low Concentrations ◽  
High Concentrations ◽  
Derivatives Of ◽  
Guinea Pig Brain

Promazine, promethazine, tetrameprazine, and WY 1172, four tranquillizing drugs that are derivatives of phenothiazine, resembled chlorpromazine in that when they were added in a concentration of 0.1 mM to slices of guinea pig brain respiring in a suitable medium they stimulated the incorporation of inorganic P32into the phospholipids of the slices. With one of the drugs, promethazine, this concentration of 0.1 mM was found to cause no significant increase in respiration, in aerobic glycolysis, or in the concentration of phosphocreatine. In higher concentrations (1.0 mM), all of the compounds inhibited the labelling of phospholipid. Promethazine caused a reduction in respiration and in the concentration of phosphocreatine, accompanied by an increase in aerobic glycolysis. Methylene blue, a derivative of phenothiazine with no reported tranquillizing properties, did not stimulate the labelling of phospholipid in brain slices. Azacyclonol, pipradrol, and mepazine, drugs that are derivatives of piperidine, also stimulated phospholipid labelling in low concentrations and inhibited the labelling at higher concentrations. Piperidine and benzhydrol, the two components from which azacyclonol is derived, did not stimulate phospholipid labelling at the concentration which was most effective for azacyclonol. Low concentrations of benzhydrol, however, caused a slight stimulation. Meprobamate and phenaglycodol, two other compounds with reputed tranquillizing action, had either little or no effect. Most of the substances tested inhibited phospholipid labelling when they were added in sufficiently high concentrations.

Action of theophylline on secretagogue-stimulated amylase release from dispersed pancreatic acini

1980 ◽  
Vol 239 (4) ◽  
pp. G324-G333
Author(s):  
L. Y. Korman ◽  
M. D. Walker ◽  
J. D. Gardner
Keyword(s):  
Guinea Pig ◽  
Vasoactive Intestinal Peptide ◽  
Enzyme Secretion ◽  
Amylase Release ◽  
Pancreatic Acini ◽  
Modes Of Action ◽  
Low Concentrations ◽  
High Concentrations ◽  
Stimulation Of

In dispersed acini from guinea pig pancreas, theophylline did not alter basal amylase release, but had three functionally distinct modes of action on the stimulation of amylase release caused by various secretagogues. 1) At relatively low concentrations (0.1-1.0 mM), theophylline augmented the increase in enzyme secretion caused by vasoactive intestinal peptide, secretin, or 8-bromoadenosine 3',5'-monophosphate, but did not alter the increase in amylase release caused by other secretagogues. 2) At intermediate concentrations (1-10 mM), theophylline selectively altered the increase in enzyme secretion caused by carbamylcholine, but did not alter the effects of cholecystokinin or bombesin, secretagogues whose modes of action are similar to that of cabamylcholine. 3) At high concentrations (greater than 10 mM), theophylline inhibited the increase in enzyme secretion caused by all secretagogues tested.

scholarly journals Comparative effect of Nickel and beta-aminobutiric Acid on some Secondary Metabolits of Echium amoenum

2015 ◽  
Vol 9 (5) ◽  
pp. 25-30 ◽  
Author(s):  
Peyman Rajaei ◽  
Neda Mohamadi
Keyword(s):  
Secondary Metabolites ◽  
Dry Weight ◽  
Aminobutyric Acid ◽  
Stress Effects ◽  
Low Concentrations ◽  
Iranian Traditional Medicine ◽  
Wonderful Variety ◽  
Research Findings ◽  
Echium Amoenum ◽  
High Concentrations

Plants have a wonderful variety of secondary metabolites which may be change due to environmental factors and stress conditions. Considering the importance of Echium amoenum in Iranian traditional medicine, this study aimed to investigate the effect of abiotic stresses on the possibility of further production of secondary metabolites in the plant. In general, according our research findings, beta-aminobutyric acid increased growth indexes. Effect of BABA on secondary metabolites was different. BABA increased plant flavonoids but reduced the tannins. Numerous studies have pointed to the stress effects of this material at high concentrations but the concentrations used in this study increased the plant growth. Nickel in applied concentrations had no significant reduction in plant dry weight but increased the photosynthetic pigments. Ni increased plant flavonoids but reduced the tannins. Nickel and beta-aminobutyric acid at low concentrations, is recommended to use for greater production of secondary metabolites in Echium cultivation.DOI: http://dx.doi.org/10.3126/ijls.v9i5.12687

scholarly journals On the Ecology of Selenium Accumulation in Plants

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 197 ◽  
Author(s):  
Elizabeth A. H. Pilon-Smits
Keyword(s):  
Dry Weight ◽  
Ecological Impacts ◽  
Trophic Levels ◽  
Future Research ◽  
Negative Effects ◽  
Low Concentrations ◽  
Elemental Defense ◽  
Litter Deposition ◽  
High Concentrations ◽  
Local Ecosystem

Plants accumulate and tolerate Se to varying degrees, up to 15,000 mg Se/kg dry weight for Se hyperaccumulators. Plant Se accumulation may exert positive or negative effects on other species in the community. The movement of plant Se into ecological partners may benefit them at low concentrations, but cause toxicity at high concentrations. Thus, Se accumulation can protect plants against Se-sensitive herbivores and pathogens (elemental defense) and reduce surrounding vegetation cover via high-Se litter deposition (elemental allelopathy). While hyperaccumulators negatively impact Se-sensitive ecological partners, they offer a niche for Se-tolerant partners, including beneficial microbial and pollinator symbionts as well as detrimental herbivores, pathogens, and competing plant species. These ecological effects of plant Se accumulation may facilitate the evolution of Se resistance in symbionts. Conversely, Se hyperaccumulation may evolve driven by increasing Se resistance in herbivores, pathogens, or plant neighbors; Se resistance also evolves in mutualist symbionts, minimizing the plant’s ecological cost. Interesting topics to address in future research are whether the ecological impacts of plant Se accumulation may affect species composition across trophic levels (favoring Se resistant taxa), and to what extent Se hyperaccumulators form a portal for Se into the local food chain and are important for Se cycling in the local ecosystem.

scholarly journals Humoral immunostimulation. IV. Role of complement.

1975 ◽  
Vol 141 (4) ◽  
pp. 736-752 ◽  
Author(s):  
W T Shearer ◽  
J P Atkinson ◽  
M M Frank ◽  
C W Parker
Keyword(s):  
Cell Growth ◽  
Guinea Pig ◽  
Human Serum ◽  
Calf Serum ◽  
Rabbit Serum ◽  
Mouse Serum ◽  
Low Concentrations ◽  
High Concentrations ◽  
Nucleoside Uptake ◽  
Pig Serum

When L cells were treated with anti-L-cell antibody in medium containing heat-inactivated fetal calf serum, nucleoside uptake and cell growth were stimulated. The response was markedly increased when fresh, unheated sera from calves, guinea pigs, humans, mice, or rabbits were also present. The factors in unheated serum responsible for the enhancement of immunostimulation were studied. Using low concentrations of sera deficient in various complement (C) components and low concentrations of antibody no augmentation of immunostimulation was seen with Clr-deficient human serum, C2-deficient human serum, C2,4-deficient human serum, C4-deficient guinea pig serum, C3-C9-depleted guinea pig serum (by administration of cobra venom factor to animals), but stimulation was observed with C5-deficient human serum, C5-deficient mouse serum, and C6-deficient rabbit serum. When the concentration of anti-serum was raised, however, augmentation was observed with C4-deficient guinea pig serum. Thus, at low concentrations of antiserum enhancement appeared to occur through the classical C pathway, whereas at high concentrations of antibody either the classical or alternate C pathways appeared to be involved. Stimulation was specifically restored by purified C2 in C2-deficient serum and by C3 in C3-C9-deficient serum. Under the usual reaction conditions consumption of guinea pig C component C4 could be demonstrated which provided direct evidence for activation of the classical C pathway under conditions leading to immunostimulation. By immunofluorescence, cells treated with antibody and normal human serum had human C3 deposited at the cell surface. Taken together these observations suggest that C activated through C3 by either the classical or alternate pathways has the potential to enhance nucleoside incorporation into DNA and cell growth of cells exposed to limiting amounts of antibody. Although the mechanism of stimulation is unknown, it is likely to involve a direct effect of C3 at the level of the cell membrane.

INCORPORATION OF INORGANIC P32INTO PHOSPHOLIPIDS OF BRAIN SLICES: EFFECT OF CERTAIN TRANQUILLIZING DRUGS

1963 ◽  
Vol 41 (5) ◽  
pp. 1155-1162 ◽  
Author(s):  
W. L. Magee ◽  
R. J. Rossiter
Keyword(s):  
Methylene Blue ◽  
Guinea Pig ◽  
Aerobic Glycolysis ◽  
Brain Slices ◽  
Inorganic P ◽  
Pig Brain ◽  
Low Concentrations ◽  
High Concentrations ◽  
Derivatives Of ◽  
Guinea Pig Brain

Promazine, promethazine, tetrameprazine, and WY 1172, four tranquillizing drugs that are derivatives of phenothiazine, resembled chlorpromazine in that when they were added in a concentration of 0.1 mM to slices of guinea pig brain respiring in a suitable medium they stimulated the incorporation of inorganic P32into the phospholipids of the slices. With one of the drugs, promethazine, this concentration of 0.1 mM was found to cause no significant increase in respiration, in aerobic glycolysis, or in the concentration of phosphocreatine. In higher concentrations (1.0 mM), all of the compounds inhibited the labelling of phospholipid. Promethazine caused a reduction in respiration and in the concentration of phosphocreatine, accompanied by an increase in aerobic glycolysis. Methylene blue, a derivative of phenothiazine with no reported tranquillizing properties, did not stimulate the labelling of phospholipid in brain slices. Azacyclonol, pipradrol, and mepazine, drugs that are derivatives of piperidine, also stimulated phospholipid labelling in low concentrations and inhibited the labelling at higher concentrations. Piperidine and benzhydrol, the two components from which azacyclonol is derived, did not stimulate phospholipid labelling at the concentration which was most effective for azacyclonol. Low concentrations of benzhydrol, however, caused a slight stimulation. Meprobamate and phenaglycodol, two other compounds with reputed tranquillizing action, had either little or no effect. Most of the substances tested inhibited phospholipid labelling when they were added in sufficiently high concentrations.

scholarly journals EFFECTS OF K-IBA AND RADICLE-CLIPPING TREATMENTS ON ROOT DEVELOPMENT OF NORTHERN RED OAK

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607f-607
Author(s):  
Daniel G. Krueger ◽  
Bert T. Swanson
Keyword(s):  
Root Development ◽  
Quercus Rubra ◽  
Dry Weight ◽  
Root Systems ◽  
Red Oak ◽  
Northern Red Oak ◽  
Stem Height ◽  
Root Dry Weight ◽  
Low Concentrations ◽  
High Concentrations

To increase root fibrosity, acorns of northern red oak (Quercus rubra L.) were germinated and subjected to several radicle clipping (+/-) and K-IBA concentration treatments combintations prior to planting. Taproots and laterals ≥ 1 mm in diameter at the point of origin were counted. Low concentrations of K-IBA (0-4000 ppm) resulted in four root morphologies: 1) a single taproot and 3-6 laterals (no clipping/no K-IBA), 2) 4-5 taproots and 1-3 laterals (clipped only), 3) a single taproot and 5-12 laterals (not clipped/K-IBA) and 4) 6-12 taproots and 1-2 laterals. High concentrations of K-IBA (4000-10,000 ppm) `clipped' unclipped radicles resulting in root systems similiar to those clipped by hand. Stem height was unaffected by treatment. Radicle-clipping may increase stem caliper. K-IBA treatments may decrease root dry weight.

Effect of Body Size on Accumulation of Po210 in Mussel, Perna viridis, at Samut Sakhon Province

2014 ◽  
Vol 931-932 ◽  
pp. 624-628 ◽  
Author(s):  
Boonsom Porntepkasemsan ◽  
Kanitha Srisuksawad ◽  
Vorapot Permnamthip
Keyword(s):  
Body Size ◽  
Body Burden ◽  
Seasonal Fluctuation ◽  
Dry Weight ◽  
Condition Index ◽  
Seasonal Effect ◽  
Perna Viridis ◽  
Wet Season ◽  
Low Concentrations ◽  
High Concentrations

Levels of 210Po in mussel (Perna viridis) collected from green mussel farming area at the Samut Sakhon province during the period of 2012 are presented. Parameters including total tissues wet weight and dry weight, maximum length, and the physiological performance of mussels using Condition Index were measured. The type of fluctuations observed with 210Po concentrations are interpreted as a seasonal effect which peaks of high concentrations in wet season and low concentrations in dry season. Analysis of 210Po activities in mussel (activity per individual) revealed the lower activities in smaller sized mussels (2.0-2.5 cm) and the higher in the larger sized group (6.5-7.0 cm). In the contrary, 210Po concentrations decreased with increasing shell length, or with increasing body size. The 210Po body burdens (activity per mussel) varied from 2.413 to 17.183 mBq while the 210Po concentrations were ranged from 2.511 to 4.474 Bq.Kg-1 ww. The results indicated that larger mussels were transfer lower 210Po concentrations to consumer on a weight basis. It is concluded that the apparent seasonal fluctuation of radionuclide concentration were mostly caused by mussel body size fluctuation and not by radionuclide body burden fluctuation.

Effects of immunological sensitization on the responses and sensitivity of guinea pig airways to bronchoconstrictors. Modulation by selective inhibition of arachidonic acid metabolism

1983 ◽  
Vol 61 (8) ◽  
pp. 876-887 ◽  
Author(s):  
Maan H. Saad ◽  
John F. Burka
Keyword(s):  
Guinea Pig ◽  
Contractile Activity ◽  
Nordihydroguaiaretic Acid ◽  
Selective Inhibition ◽  
Arachidonic Acid Metabolism ◽  
Resting Tension ◽  
Low Concentrations ◽  
High Concentrations ◽  
Inhibitor Treatment

The force generated by tracheal spirals and lung parenchymal strips from normal and ovalbumin-sensitized guinea pigs was measured in vitro, after challenge with histamine, carbachol, leukotriene (LT) C4, LTD4, or a prostaglandin endoperoxide analog (U-44069). The responses and sensitivity of airway tissues to the above agonists were identical in normal and sensitized animals. Treatment of tracheal spirals with indomethacin (8.5 μM), phenidone (185 μM), and nordihydroguaiaretic acid (NDGA: 30 μM) reduced resting tension (tone) equally in both normal and sensitized trachea, but did not affect lung parenchymal strips from either group. The responses of tracheal spirals from normal and sensitized animals to low concentrations of histamine, carbachol, LTC4, and LTD4 were reduced or abolished by treatment with the above inhibitors. Responses to higher concentrations of the same agonists were significantly enhanced. In contrast, treatment of normal and sensitized trachea with indomethacin (2.8 and 8.5 μM) did not abolish or reduce the effects of low concentrations of U-44069. However, an enhancement of the effect of high concentrations occurred only on normal tracheal spirals, even though the control tissues from each group responded identically with U-44069 in the absence of any inhibitor. Parenchymal strips increased in sensitivity to histamine, but not carbachol, as a result of time, vehicle, or prior exposure to the drug. Inhibitor treatment did not affect sensitivity or responsiveness of parenchyma to histamine, carbachol, and U-44069, but the contractile activity of LTD4 on both normal and sensitized lung parenchymal strips was reduced by indomethacin, NDGA, and phenidone. We conclude that ovalbumin sensitization does not induce hyperreactivity of guinea pig airways.

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