Racial Differences Between North American and European Forms of Balanus Balanoides

1964 ◽  
Vol 44 (1) ◽  
pp. 33-45 ◽  
Author(s):  
D. J. Crisp
Keyword(s):  
New England ◽  
Racial Differences ◽  
Close Correlation ◽  
Western Atlantic ◽  
Food Conditions ◽  
General Locality ◽  
Temperature Levels ◽  
Balanus Balanoides ◽  
Two Populations

After transplantation and acclimatization of populations of the barnacle Balanus balanoides from the coast of New England to the Menai Straits, differences in breeding behaviour persisted over a period of from 4 to 18 months. The two populations are believed to belong to distinct physiological races.The New England populations fertilized 1½–3 weeks in advance of adjacent British populations.Embryonic development in the post-cleavage stages of the New England population proceeded in vitro at about twice the rate of the development of the British population, under identical conditions.The volume of the eggs of the New England population was 1.3–1.6 times as great as the volume of the eggs of the British specimens.Both populations, when growing in British waters, liberated their nauplii in March at a time which coincided with the beginning of the vernal plankton increase in the locality. The embryos of the American population had therefore remained in the mantle space for a much longer period than had those of the British specimens and for a longer period than that reported for New England populations in their native habitat.In B. balanoides the time of fertilization and rate of development may be genetically adapted in each general locality so that the embryos reach full term before the plankton increase is due. The actual time of liberation is then mediated by the hatching substance in response to prevailing food conditions.If the B. balanoides population of the Western Atlantic area as a whole belongs to a physiological race distinct from that of the Eastern Atlantic, and responding differently to temperature levels at the breeding season, there is no reason to expect any close correlation in respect of environmental conditions between the southern limits of the species in Europe and in America.

scholarly journals Precious corals (Coralliidae) from north-western Atlantic Seamounts

2010 ◽  
Vol 91 (2) ◽  
pp. 369-382 ◽  
Author(s):  
Anne Simpson ◽  
Les Watling
Keyword(s):  
New Species ◽  
New England ◽  
Additional Species ◽  
Western Atlantic ◽  
Straits Of Florida ◽  
Coral Genus ◽  
Two New Species ◽  
North Western

Two new species belonging to the precious coral genus Corallium were collected during a series of exploratory cruises to the New England and Corner Rise Seamounts in 2003–2005. One red species, Corallium bathyrubrum sp. nov., and one white species, C. bayeri sp. nov., are described. Corallium bathyrubrum is the first red Corallium to be reported from the western Atlantic. An additional species, C. niobe Bayer, 1964 originally described from the Straits of Florida, was also collected and its description augmented.

An Appraisal of Genetic Studies on Leprosy

1972 ◽  
Vol 21 (1-2) ◽  
pp. 21-52 ◽  
Author(s):  
Bernardo Beiguelman
Keyword(s):  
Racial Differences ◽  
Genetic Markers ◽  
Genetic Factors ◽  
Twin Pair ◽  
Critical Discussion ◽  
Australia Antigen ◽  
Genetic Studies ◽  
Mechanism Of Resistance ◽  
Familial Association

SummaryThe present paper reviews the research lines which have been explored to evaluate to what extent genetic factors are intervening on the mechanism of resistance and susceptibility to leprosy.It presents a critical discussion of the investigations on the familial association of leprosy, familial association of leprosy types, intrafamilial contagion of leprosy, concordance of leprosy in twinpairs, racial differences on leprosy prevalence and lepromatous rate, pedigree studies, association of leprosy to genetic markers, Australia antigen, and dermatoglyphic patterns. Space was also allotted to review family and twin-pair studies on the Mitsuda reaction, as well as to the investigation on the in vitro behaviour of blood macrophages against killed M. leprae.Some areas in which further research on leprosy and genetics may be considered as prioritary are outlined with some detail.

scholarly journals The Association Between In Vitro Propiconazole Sensitivity and Field Efficacy of Five New England Sclerotinia homoeocarpa Populations

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 552-561 ◽  
Author(s):  
James T. Popko ◽  
Chang-Ho Ok ◽  
Katie Campbell-Nelson ◽  
Geunhwa Jung
Keyword(s):  
New England ◽  
Field Resistance ◽  
Golf Club ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Mycelium Growth ◽  
Turfgrass Disease ◽  
Country Club ◽  
Field Efficacy

Dollar spot (Sclerotinia homoeocarpa) is a major turfgrass disease requiring fungicide application to maintain acceptable conditions for golf. A 2-year field experiment was conducted to determine the association between field efficacy of propiconazole and in vitro fungicide sensitivity of isolates from five S. homoeocarpa populations. Four golf courses with prior propiconazole exposure (Hartford Golf Club, Hickory Ridge Country Club, Shuttle Meadow Country Club, and Wintonbury Hills Golf Club), and a baseline site with no prior propiconazole exposure (Joseph Troll Turf Research Facility) were chosen as field sites. Experimental plots at each site received the following treatments at 21-day intervals: untreated, propiconazole (0.44, 0.88, 1.32, and 1.76 kg a.i. ha–1), and chlorothalonil (8.18 kg a.i. ha–1). S. homoeocarpa isolates were sampled at three time points during 2009 and 2010: initial (directly before fungicide treatment), 7 days after treatment (DAT), and 21 days after the last treatment. Isolates sampled from dollar spot infection centers at 7 DAT (2009 and 2010) were considered to exhibit “practical field resistance”. In parallel, S. homoeocarpa isolates from each site were assayed for in vitro sensitivity to propiconazole by determining relative mycelium growth percentages (RMG%) on potato dextrose agar amended with propiconazole at a discriminatory concentration of 0.1 μg a.i. ml–1. S. homoeocarpa isolates from the four exposed populations displayed significantly higher RMG% values than the baseline population. In general, field efficacy at all propiconazole rates tested was lower at the four locations with prior propiconazole exposure when compared with the baseline population. Increased RMG% values on the propiconazole discriminatory concentration 0.1 μg a.i. ml–1 were associated with decreased relative control values for all propiconazole rates in 2009 and 2010. Results suggest RMG values above 50% at the propiconazole discriminatory concentration of 0.1 μg a.i. ml–1 may be a suitable threshold for detection of S. homoeocarpa isolates that cause practical DMI field resistance.

Molecular forms and thermal and kinetic properties of purified glutathione reductase from two populations of barnyard grass (Echinochloa crus-galli(L.) Beauv.: Poaceae) from contrasting climatic regions in North America

2000 ◽  
Vol 78 (7) ◽  
pp. 969-980 ◽  
Author(s):  
Nadia Hakam ◽  
Jean-Pierre Simon
Keyword(s):  
Glutathione Reductase ◽  
Thermal Adaptation ◽  
Catalytic Efficiency ◽  
Molecular Forms ◽  
Kinetic Properties ◽  
Barnyard Grass ◽  
Climatic Regions ◽  
Two Populations ◽  
Menten Constant

The thermal, kinetic, and electrophoretic properties of purified glutathione reductase (GR; EC 1.6.4.2) were analyzed in plants from two ecotypes of barnyard grass (Echinochloa crus-galli (L.) Beauv.: Poaceae) originating from sites of contrasting climates in Quebec (QUE) and Mississippi (MISS). Crude and purified GR preparations from plants of both ecotypes consisted of one homodimer isomorph with the same electrophoretic mobility in polyacrylamide gels, a similar molecular mass for the native enzyme (98 kDa) and for each subunit of the dimer (44 kDa), and an identical pI of 5.9. The electrophoretic profile of GR purified from cold-acclimated plants at 14°C light (L) : 8°C dark (D) for 10 days was similar to that of GR from plants grown at 26°C L : 20°C D. Specific activities of purified GR from QUE plants were significantly higher than those of MISS plants. In vitro GR activities from QUE and MISS plants were not differentially affected by thermodenaturation at 55 or 65°C or by cold treatments at 2°C. Apparent energies of activation (Ea) of GR purified from QUE and MISS plants were similar with the exception of estimates of Ea(oxidized glutathione) for Q10(15-5°C) for which significantly lower values were obtained for QUE plants. No differences of physiological significance were observed for Km(Michaelis-Menten constant) values of GR purified from QUE and MISS plants. However, both Vmaxand Kcat(turnover numbers) estimates were significantly higher for GR purified from QUE plants over most of the range of assay temperatures, suggesting superior catalytic efficiency for the enzyme of the cold-adapted ecotype from Québec.Key words: barnyard grass, ecotypes, electrophoresis, enzyme kinetics, glutathione reductase, thermal adaptation.

Regional variation of series elasticity in canine arterial smooth muscles

1978 ◽  
Vol 234 (5) ◽  
pp. H542-H551 ◽  
Author(s):  
R. H. Cox
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Regional Variation ◽  
Smooth Muscles ◽  
Muscle Length ◽  
Close Correlation ◽  
Contractile Element ◽  
Active Stress ◽  
Elastic Elements

Segments of carotid, iliac, renal, mesenteric, coronary, and internal thoracic arteries were studied in vitro to correlate the mechanical properties of series (SE) and parallel (PE) elastic elements with connective tissue (CT) composition and with active responses to potassium activation. The PE properties were determined using pressure-diameter data with passive smooth muscle (SM). SE properties were determined from periodic incremental releases imposed during isometric responses to [K+]O at a diameter corresponding to Lmax, the optimum muscle length. Active stress responses and diameter responses were determined using pressure-diameter data for active and passive conditions. Collagen and elastin contents were determined for each sample. No correlation was found between CT content and PE or SE properties for the various sites. A close correlation was found to exist between SE and PE properties at each site, i.e., the sites with the stiffest PE also had the stiffest SE. SM, with stiffer SE, had a larger diameter response with the same active stress response and the same diameter response with a smaller active stress response, compared to SM with more compliant SE. This suggests that passive properties of SM can have a significant influence on the external manifestations of contractile element properties.

Arteriolar endothelial cell barrier separates two populations of muscarinic receptors

1992 ◽  
Vol 262 (4) ◽  
pp. H1311-H1315 ◽  
Author(s):  
R. J. Rivers ◽  
B. R. Duling
Keyword(s):  
Endothelial Cell ◽  
Muscarinic Receptors ◽  
Vessel Wall ◽  
Cheek Pouch ◽  
Different Populations ◽  
Differential Control ◽  
Two Sides ◽  
Two Populations

The endothelium of arterioles can function as a barrier to diffusion of hydrophilic molecules when studied in vitro. Thus a substance applied to one side of the arteriole is relatively ineffective in reaching receptors on the opposite side of the vessel wall unless it is lipid soluble. To study the receptor populations on the two sides of the arteriolar endothelium, we used micropipettes to apply methacholine (MCh; 1.0 microM), either luminally or adventitially, for 5 s to the arterioles of the cheek pouch of pentobarbital-anesthetized hamsters. MCh equally dilated the arterioles regardless of the side of application. That different populations of receptors are located on either side of the arteriole was shown by the fact that adventitially applied hydrophilic methscopolamine was ineffective in blocking the effects of the luminally applied MCh but completely blocked the effects of abluminally applied MCh. In contrast, the luminal population of receptors was easily blocked by adventially applied scopolamine, which is lipophilic. Separate and independent populations of receptors in the vessel wall suggests the potential for differential control between humoral and adventitial sources of vasoactive metabolites.

Antiplatelet Effect Of A New Compound, Imidazo[1,2-a]- Thienopyrimidin-2-One : A Cyclic AMP Mediated Phenomenon

1981 ◽  
Author(s):  
S Ashida ◽  
K Sakuma ◽  
Y Abiko
Keyword(s):  
Platelet Aggregation ◽  
Membrane Fraction ◽  
Close Correlation ◽  
Inhibitory Effect ◽  
Camp Level ◽  
Camp Phosphodiesterase ◽  
Pde Inhibitors ◽  
Camp Metabolism ◽  
Oral Doses

The effect of a new compound, 1,2,3,5,6,7,8,9-Octahydro- [1]benzothieno[2,3-d]imidazo[1,2-a]pyrimidin-2-one hydrochloride (DH-6471), on cAMP metabolism and aggregation of platelets was studied. In vitro. DH-6471 inhibited platelet aggregation (both the 1st and 2nd phases) induced by ADP, collagen, thrombin, arachidonic acid and PGG2-TXA2 mixture in PRP from various animal species including human at concentrations (IC50) ranging from 0.07 to 8 μH. It inhibited ADP- and collagen-induced platelet aggregation ex vivg in rats following oral doses as low as 0.3- 1 mg/kg.The compound was found to be a highly selective inhibitor of platelet low Km cAMP phosphodiesterase (Ki=0.025 μM), when tested with enzyme fractions separated by DEAE-cellu-lose chromatography. It did not significantly affect basal or PGE1(0.1-1 μM)-stimulated cAMP level of platelets at a concentration of 1 μM where platelet aggregation and the low Km PDE were markedly inhibited. However, both basal and PGE1-stimulated accumulations of cAMP in the platelet membrane fraction were increased by DH-6471 at 1 μM when the isolated membrane fraction was incubated with ATP-Mg2+.Studies with several PDE inhibitors including papaverine, dipyridamole and DH-6471-related compounds showed a close correlation between their ability to inhibit the low Km PDE or to increase cAMP accumulation in the membrane fraction and their inhibitory effect on platelet aggregation. On the other hand, their potency to inhibit high Km cAMP-PDE(cGMP-PDE) and to increase cAMP level in whole platelets was poorly correlated to their inhibitory activity in platelet aggregation.These results suggest that some small but local changes in platelet cAMP may be involved in the regulation of platelet aggregation, particularly primary aggregation.

Composition and In vitro Antimicrobial Activities of the Essential Oils of Two Populations ofThymus numidicusPoiret

2009 ◽  
Vol 21 (4) ◽  
pp. 374-377 ◽  
Author(s):  
Hocine Laouer ◽  
Nacira Boulaacheb ◽  
Salah Akkal ◽  
Uwe J. Meierhenrich ◽  
Nicolas Baldovini ◽  
...  
Keyword(s):  
Essential Oils ◽  
Antimicrobial Activities ◽  
Two Populations

Parameters and Methods for Testing Artificial Heart Valves

1989 ◽  
Vol 12 (4) ◽  
pp. 252-260 ◽  
Author(s):  
J.C. Köhler ◽  
J.G. Tech
Keyword(s):  
Heart Valves ◽  
Close Correlation ◽  
Test Methods ◽  
In Vitro Tests ◽  
Geometrical Parameters ◽  
Test Standards ◽  
Artificial Heart Valves ◽  
Minimum Requirements ◽  
Definition Of

The report describes the development of heart valve test standards. The aim is comprehensive quality assurance by in vitro tests. The project includes three test fields: general basis, development and definition of test methods and test devices and comparative in vitro assessment of valves for the definition of minimum requirements. A preliminary list of test parameters and test steps has been defined: geometrical, flow, deformation, force, and conditioning parameters. A system of geometrical parameters has been developed for standardized aortic models. Geometrical parameters of 31 valves of six types and different sizes underline a close correlation between geometrical and hemodynamic parameters. The relative ostium cross-section Ae/AT increases with valve size and lies between 0.3 and 0.5. Two new measurement devices with quasi-steady flow are proposed as quick testers for leakage flow and pressure loss.

scholarly journals Primary leukemia cells resistant to alpha-interferon in vitro are defective in the activation of the DNA-binding factor interferon- stimulated gene factor 3

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1942-1949 ◽  
Author(s):  
B Xu ◽  
D Grander ◽  
O Sangfelt ◽  
S Einhorn
Keyword(s):  
Close Correlation ◽  
Lymphocytic Leukemia ◽  
Alpha Interferon ◽  
Leukemia Cells ◽  
Blast Transformation ◽  
Oligoadenylate Synthetase ◽  
Binding Factor ◽  
Ifn Treatment ◽  
Possible Cause

Abstract Cells from one-third of chronic lymphocytic leukemia (CLL) patients are resistant to alpha-interferon (alpha-IFN) as measured by induction of blast transformation. We have previously shown that all CLL clones express alpha/beta-IFN receptors, but that the resistant cells are defective in the induction of the enzyme 2′,5′-oligoadenylate synthetase (2′,5-A synthetase). Thus, the deficiency in IFN sensitivity is localized somewhere between the interaction of the IFN molecule with its receptor and induction of 2′,5′-A synthetase. We have now further characterized the resistance of CLL clones to IFN by investigating whether it is associated with a defect in the activation of IFN- stimulated gene factor 3 (ISGF3), which is involved in the activation of alpha-IFN-stimulated genes (ISGs). A defect induction of ISGF3 after alpha-IFN treatment was found in 4 of 12 CLL patients. There was a close correlation between defective induction of ISGF3 and a lack of enhancement of 2′,5′-A synthetase as well as induction of blast transformation. Pretreatment with gamma-IFN and mixing experiments with extracts from IFN-sensitive cells indicate that a lack of the gamma- component of ISGF3 was the reason for defect in activation in 2 of the patients. We conclude that a defect in activation of ISGF3 is a possible cause for resistance in CLL cells to IFN-induced blast transformation in vitro.

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