Gene/Protein Disease Symptom Drug Enzyme Compound
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Bacteriophage phi6 nucleic acid was present as a torus after chromic acid-formaldehyde-OSO4 fixation and acetone and propylene oxide dehydration. A herpes virus, infectious bovine rhinotracheitis virus, had its DNA mostly as a torus, collapsed in the centre, or as a network, after glutaraldehyde-OSO4 fixation, but in an uncollapsed torus or network formation after chromic acid-formaldehyde-OSO4. This fixative stabilized nucleic acids, allowing acetone dehydration and plastic embedding without collapse of nucleic acid to the centre of the virion.
J Gen Virol 1978 May
PMID:Chromic-acid formaldehyde fixation of nucleic acids of bacteriophage phi6 and infectious bovine rhinotracheitis virus. 20 62

The volume of the cells and lateral intercellular spaces were measured in living Necturus gallbladder epithelium. Under control conditions, the volume of the lateral spaces was 9% of the cell volume. Replacement of mucosal NaCl by sucrose or tetramethylammonium chloride (TMACl) caused intercellular spaces to collapse. During mucosal NaCl replacement, cell volume decreased to 79% of its control value. When NaCl was reintroduced into the mucosal bath, the intercellular spaces reopened and the cells returned to control volume. The NaCl active transport rate, calculated from the rate of cell volume decrease, was 266 pM/cm2.s, close to the observed rate of transepithelial salt transport. It was calculated from the decrease in cell volume that all of the intracellular NaCl was transported out of the cell during removal of mucosal NaCl. The flux of salt across the apical membrane, calculated from the rate of cell volume increase upon reintroducing mucosal NaCl, was 209 pM/cm2.s, in good agreement with estimates by other methods. The electrical resistance of the tight junctions was estimated to be 83.9% of the total tissue resistance in control conditions, suggesting that the lateral intercellular spaces normally offer only a small resistance to electrolyte movement.
J Gen Physiol 1979 Mar
PMID:Fluid transport and the dimensions of cells and interspaces of living Necturus gallbladder. 43 73

Japanese quail of the strain used in our laboratory do not show a complete decrease in levels of circulating luteinizing hormone (LH) concentrations and show no collapse of the testes following their transfer from long to short days under laboratory conditions. Thus, merely manipulating photoperiods in the laboratory does not simulate an annual breeding cycle. To see whether an annual breeding cycle does exist in "our" quail under natural conditions, mature male birds were housed in individual cages and placed on the roof of a building at 35 degrees 45'N, 139 degrees 53'E; day length and ambient temperature were not controlled at all though food and water were continuously supplied. For 16 months blood was collected every week and the area of the cloacal protrusion measured at the time of each blood collection. The results showed that levels of plasma LH and the area of the cloacal protrusion had a clear annual cycle under the natural conditions. To detect more precisely the changes in circulating LH concentrations during spring and autumn, samples were collected every other day. The first significant increase in levels of plasma LH was found when the day length exceeded 12-12.5 hr, though the increase was sporadic and not synchronized among individuals. The results also showed that circulating levels of LH declined significantly in early September starting when the day length was still about 14 hr; this downward trend continued rather steadily to nonbreeding levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Gen Comp Endocrinol 1992 Mar
PMID:Annual changes in levels of plasma LH and size of cloacal protrusion in Japanese quail (Coturnix coturnix japonica) housed in outdoor cages under natural conditions. 157 44

Bioenergetic properties of a mutant strain of Escherichia coli K12 designated TUV, which is resistant to the protonophoric uncoupling agent 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidiazole (TTFB) have been compared with those of its non-resistant parent, E. coli K12 Doc-S. Strain TUV grew and respired some 20-30% faster than strain Doc-S, and was cross-resistant to carbonylcyanide p-(trifluoromethoxy)phenylhydrazone and triphenyltin, but not to 2,4-dinitrophenol. Phosphorus nuclear magnetic resonance demonstrated the TTFB-mediated collapse of the transmembrane pH gradient at identical rates in starved cells of both strains, indicating that uncoupler access and function were unimpaired in the mutant under these conditions. Strain TUV displayed enhanced uncoupler resistance and maintained intracellular pH and ATP levels only when respiring. On the other hand, strain TUV also showed increased resistance to novobiocin, implying that its outer wall permeability had been lowered. We suggest that the active resistance of strain TUV results from the exclusion of uncoupler by the interaction of inner and outer membrane components in a manner modulated by the degree of cellular energization.
J Gen Microbiol 1989 Oct
PMID:Uncoupler resistance in Escherichia coli: the role of cellular respiration. 269 12

A membrane protein that is immunochemically similar to the red cell anion exchange protein, band 3, has been identified on the basolateral face of the outer medullary collecting duct (MCD) cells in rabbit kidney. In freshly prepared separated rabbit MCD cells, M.L. Zeidel, P. Silva and J.L. Seifter (J. Clin. Invest. 77:1682-1688, 1986) found that C1-/HCO-3 exchange was inhibited by the stilbene anion exchange inhibitor, DIDS (4,4'-diisothiocyano-2,2'-disulfonic stilbene), with a K1 similar to that for the red cell. We have measured the binding affinities of a fluorescent stilbene inhibitor, DBDS (4,4'-dibenzamido-2,2'-disulfonic stilbene), to MCD cells in 28.5 mM citrate and have characterized both a high-affinity site (Ks1 = 93 +/- 24 nM) and a lower affinity site (Ks2 = 430 +/- 260 nM), which are closely similar to values for the red cell of 110 +/- 51 nM for the high-affinity site and 980 +/- 200 nM for the lower affinity site (A.S. Verkman, J.A. Dix & A.K. Solomon, J. Gen. Physiol. 81:421-449, 1983). When Cl- replaces citrate in the buffer, the two sites collapse into a single one with Ks1 = 1500 +/- 400 nM, similar to the single Ks1 = 1200 +/- 200 nM in the red cell (J.A. Dix, A.S. Verkman & A.K. Solomon, J. Membrane Biol. 89:211-223, 1986). The kinetics of DBDS binding to MCD cells at 0.25 microM-1 are characterized by a fast process, tau = 0.14 +/- 0.03 sec, similar to tau = 0.12 +/- 0.03 sec in the red cell. These similarities show that the physical chemical characteristics of stilbene inhibitor binding to MCD cell 'band 3' closely resemble those for red cell band 3, which suggests that the molecular structure is highly conserved.
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PMID:Relation between the anion exchange protein in kidney medullary collecting duct cells and red cell band 3. 318 73

An apnea hypothesis is proposed termed Conditioned Hyperventilation. An organism (animal, infant, or adult) can become conditioned to anticipate traumatic terminal breathing. The resulting hyperventilation produces excessive oxygen, which triggers apnea, allowing an increase in carbon dioxide. This apnea serves as an additional unconditioned stimulus (UCS) causing the hyperventilation (apnea) to increase. Organic blockage can also serve as the UCS. Apnea may be reduced or prevented by monitoring and extinguishing hyperventilation through the use of behavioral modification techniques, or biofeedback. Infant lung collapse during the first six months is suggested as one UCS in infants.
Genet Soc Gen Psychol Monogr 1986 Aug
PMID:Conditioned hyperventilation as a factor in animal, infant, and adult apnea: a theoretical analysis of experimental and clinical data. 377 Apr 64

Collapsed walls of vitellogenic follicles from the lizard Anolis carolinensis were placed in an in vitro system to measure contractility. Three initial tensions were utilized, 0.15, 1.5, and 10.0 g; the latter, after relaxation, produced follicles with a tension similar to that on the wall of an intact vitellogenic follicle. Follicles at each tension then were exposed to either saline or 50 ng/ml arginine vasotocin (AVT). Spontaneous, rhythmic follicular contractions occurred (approx one every 3 min), regardless of initial tension. The higher the initial tension, however, the greater the amplitude of the contractions. Treatment with AVT did not influence any parameter of rhythmic contraction. This report of rhythmic contractions of whole follicular walls of Anolis suggests that contractile activity of myofibroblasts in the wall plays a role in follicular growth and/or ovulation.
Gen Comp Endocrinol 1984 Nov
PMID:Spontaneous, rhythmic contractions of the ovarian follicular wall of a lizard (Anolis carolinensis). 651 Jun 87

Triiodothyronine (T3) was measured by double antibody radioimmunoassay in the sera of individuals of all stages of the life cycle in the sea lamprey, Petromyzon marinus, and in larval (ammocoetes) and metamorphosing individuals of the brook lamprey, Lampetra lamottenii. There was no significant difference in results from the two species. Although serum T3 concentration did not vary significantly in ammocoetes maintained at the same temperature throughout the year, concentrations in ammocoetes displayed an inverse response to fluctuations in water temperature. Ammocoetes maintained at temperatures of 7 to 10 degrees and 19 to 21 degrees exhibited significantly different circulating T3 levels of 2400 and 1550 ng dl-1, respectively. Therefore, it is expected that there may be some seasonal variation in the levels of the hormone in ammocoetes in their natural environment. A precipitous collapse of the serum levels of T3 was observed by an early stage of metamorphosis (100 ng dl-1) and no significant difference in levels was observed throughout the remaining period of this phase. Young parasitic adults and adult lampreys collected during their spawning migration (upstream migrants) exhibited circulating T3 concentrations of 40 and 30 ng dl-1, respectively. T3 levels in some upstream migrants were below the limit of detection (less than 5 ng dl-1). The metamorphic decline in serum T3 may simply mark the beginning of the lower T3 levels that characterizes the adult serum.
Gen Comp Endocrinol 1983 Feb
PMID:Concentration of triiodothyronine in the sera of the sea lamprey, Petromyzon marinus, and the brook lamprey, Lampetra lamottenii, at various phases of the life cycle. 684 May 15

Incubation of a strain of Escherichia coli K12 with 25 mM-methyl methanesulphonate (MMS) for 1 h changed the sedimentation coefficient of the nucleoids from 1600S to 850S. When isolated nucleoids were treated with MMS under identical conditions in vitro there was no change in the sedimentation coefficient. Alkaline sucrose-gradient centrifugation of DNA from cells treated with 25 mM-MMS for 1 h indicated that there were approximately 100 breaks plus apurinic sites per chromosome. Titration with ethidium bromide of nucleoids from MMS-treated cells showed that almost all supercoiling had been lost, suggesting that the breaks plus apurinic sites consisted mostly of breaks. Further experiments showed that the apurinic sites were probably created by non-enzymic depurination and that little non-enzymic strand breakage had occurred. The depurinated sites thus created could then serve as substrates for the apurinic-specific endonucleases of the cell, with the result that strand breakage occurred. MMS treatment did not cause any changes in the DNA:RNA ratio of the nucleoids. Removal of MMS followed by a period of incubation resulted in a decrease in the number of breaks plus apurinic sites and an increase in the sedimentation coefficient of the nucleoids. After 2 h incubation in MMS-free medium the sedimentation coefficient of the nucleoids from MMS-treated cells was the same as that of the control; the supercoiling was also partially restored. The effect of MMS on two MMS-sensitive mutants of E. coli, one a polA and the other a recA mutant, was also studied. In both cases MMS caused complete collapse of the nucleoid structure.
J Gen Microbiol 1981 May
PMID:Effect of methyl methanesulphonate on the nucleoid structure of Escherichia coli. 703 62

The electrical potential (delta psi) and proton gradient (alpha pH) across the membranes of isolated bovine chromaffin granules and ghosts were simultaneously and quantitatively measured by using the membrane-permeable dyes 3,3'dipropyl-2,2'thiadicarbocyanine (diS-C3-(5)) to measure delta psi and 9-aminoacridine or atebrin to measure delta pH. Increases or decreases in the delta psi across the granular membrane could be monitored by fluorescence or transmittance changes of diS-C3-(5). Calibration of the delta psi was achieved by utilization of the endogenous K+ and H+ gradients, and valinomycin or carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), respectively, with the optical response of diS-C3-(5) varying linearly with the Nernst potential for H+ and K+ over the range -60 to +90 mV. The addition of chromaffin granules to a medium including 9-aminoacridine or atebrin resulted in a rapid quenching of the dye fluorescence, which could be reversed by agents known to cause collapse of pH gradients. From the magnitude of the quenching and the intragranular water space, it was possible to calculate the magnitude of the alpha pH across the chromaffin granule membrane. The time-course of the potential-dependent transmittance response of diS-C3-(5) and the delta pH-dependent fluorescence of the acridine dyes were studied simultaneously and quantitatively by using intact and ghost granules under a wide variety of experimental conditions. These results suggest that membrane-permeable dyes provide an accurate method for the kinetic measurement of delta pH and delta psi in an amine containing subcellular organelle.
J Gen Physiol 1980 Feb
PMID:Spectrophotometric measurements of transmembrane potential and pH gradients in chromaffin granules. 737 77


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