The relationship between parasite load, crawling behaviour, and growth rate of Macoma balthica (L.) (Mollusca, Pelecypoda) from Hudson Bay, Canada

1991 ◽  
Vol 69 (8) ◽  
pp. 2202-2208 ◽  
Author(s):  
Shirley S. L. Lim ◽  
Roger H. Green
Keyword(s):  
Growth Rate ◽  
Macoma Balthica ◽  
High Tide ◽  
Somatic Growth ◽  
Parasite Load ◽  
Final Host ◽  
Hudson Bay ◽  
Tidal Level ◽  
Annual Growth Rings ◽  
The Difference

At ebb tide Macoma balthica makes crawling tracks on the intertidal sand flats near Churchill, Manitoba, on Hudson Bay. Clams from two tidal levels, mean low water and 1.0 m above mean low water, were sampled to compare the parasite load and growth rate of crawling versus buried Macoma. For each clam the number of trematode metacercariae present were counted and the growth rate was determined by the measurement of annual growth rings. Clams were infected by more metacercariae at the higher than at the lower tidal level, larger clams more than smaller ones and crawling clams more than buried ones. Increased exposure of the clams at the higher tidal level to shorebirds, the final host of the trematodes, is proposed as the reason for the difference in parasite load between the tide levels. High-tide clams (more parasitized) grew faster than low-tide ones (less parasitized), and crawlers (more parasitized) grew faster than the buried (less parasitized) clams. Enhanced somatic growth as a result of parasitic castration is proposed to be the most logical explanation to account for the faster growth of the parasitized clams.

Variations de la croissance de la coquille, et de la structure d'âge du bivalve Macoma balthica (L.) dans une population intertidale de l'estuaire du Saint-Laurent (Québec)

1987 ◽  
Vol 65 (8) ◽  
pp. 1906-1916 ◽  
Author(s):  
Bruno Vincent ◽  
Claude Brassard ◽  
Michel Harvey
Keyword(s):  
Growth Rate ◽  
Water Level ◽  
Shell Growth ◽  
Macoma Balthica ◽  
Annual Growth ◽  
Annual Growth Rate ◽  
Tidal Level ◽  
Lawrence Estuary ◽  
Mean Water Level ◽  
Shell Growth Rate

Greater annual shell growth rate and increased mortality are observed in Macoma balthica (L.) with an increase of immersion time in the intertidal zone of the St. Lawrence estuary. There is also a greater annual growth rate in tidal pools, and sediment temperature alone may explain spatial variations in spring and annual growth. Reciprocal transfers of specimens between upper (0.8 m above mean water level) and lower (1.2 m below mean water level) tidal level result in enhanced shell growth for individuals of the upper level transferred to the lower level. There is no corresponding change of shell growth rate for individuals of the lower level. This genotypic difference in short-term physiological responses to environmental changes may be the result of different selective pressures associated with habitat temporal heterogeneity. An opportunistic strategy is associated with the more terrestrial and unpredictable environment (upper tidal level) and a more specialized strategy accompanied by low phenotypic variability is associated with the more marine and stable environment (lower tidal level).

An Arctic Intertidal Population of Macoma balthica (Mollusca, Pelecypoda): Genotypic and Phenotypic Components of Population Structure

1983 ◽  
Vol 40 (9) ◽  
pp. 1360-1371 ◽  
Author(s):  
Roger H. Green ◽  
Shiva M. Singh ◽  
Beverly Hicks ◽  
Janet M. McCuaig
Keyword(s):  
Growth Rate ◽  
Macoma Balthica ◽  
Electrophoretic Analysis ◽  
Annual Rings ◽  
Lethal Temperature ◽  
Tidal Level ◽  
Tide Level ◽  
The Mean ◽  
Intertidal Population ◽  
Lower Tolerance

In July 1980 we collected live Macoma balthica from populations at two tide levels near Fort Churchill, Man., Canada. Upper lethal temperature tolerances were determined for clams from the mean low water (MLW) tidal level and from 1.1 m above MLW tidal level, after which all specimens were hard frozen for later electrophoretic analysis. Of 22 loci evaluated, the following were polymorphic: AKP, ACP, EST, LAP, MDH, and ME. Genotypes at these loci were related to tide level, growth rate, tolerance to high temperature, and age. Analysis of shell annual rings verified an earlier report of much faster growth in the higher tide level population. Growth rate and degree of heterozygosity are both higher at 1.1 m than at MLW. Degree of heterozygosity increases with age, suggesting selection against homozygotes. At 1.1 m, but not at MLW, individuals with higher growth rates have lower tolerance to high temperatures and a higher degree of heterozygosity. Similar patterns are described for the six individual loci.

Naturally occurring activity variation of an alkaline phosphatase isozyme associated with physiological fitness in an intertidal population of Macoma balthica

1986 ◽  
Vol 28 (2) ◽  
pp. 282-285 ◽  
Author(s):  
Shiva M. Singh ◽  
Roger H. Green
Keyword(s):  
Alkaline Phosphatase ◽  
Macoma Balthica ◽  
High Tide ◽  
Activity Level ◽  
Hudson Bay ◽  
Biochemical Basis ◽  
Physiological Fitness ◽  
Naturally Occurring ◽  
Intertidal Population ◽  
Enzyme Alkaline Phosphatase

We observed variability in the level of an isozyme for the enzyme alkaline phosphatase (AKP, EC 3.1.3.1) in a Macoma balthica population from Hudson Bay. The distribution of "high" and "no" activity AKP-2 variants were different in samples from "high" tide as compared with "low" tide areas. Furthermore, the AKP-2 activity level is associated with survival at high temperature (32 °C), but in the "high" tide subpopulation only. Although this striking association between the activity level of an isozyme and an environmental parameter in a natural population is one of the very few in the literature, further studies are required to establish the genetic basis for the level of the enzyme activity and the biochemical basis for this relationship.Key words: isozyme, alkaline phosphatase, natural selection, evolution.

A Model of Wheat Grain Growth and Its Applications to Different Temperature and Carbon Dioxide Levels

1995 ◽  
Vol 22 (5) ◽  
pp. 843 ◽  
Author(s):  
YP Wang ◽  
RM Gifford
Keyword(s):  
Growth Rate ◽  
Grain Growth ◽  
Temperature Response ◽  
Rate Sensitivity ◽  
Temperature Sensitive ◽  
Potential Growth ◽  
Carbon Supply ◽  
The Difference ◽  
Carbon Dioxide Levels ◽  
Kernel Growth

Kernel growth after anthesis is simulated as a function of the potential kernel growth rate, current photosynthate production and mobilisation of stored reserves. The potential growth rate of the kernel is simulated as two temperature-sensitive processes, cell production and cell growth. The difference between the potential and actual growth rates of the kernel depends on the carbon supply to the free space of the kernel endosperm, while the carbon supply is itself affected by the actual kernel growth rate. Sensitivity analysis showed that the growth rate of the grain per plant is most sensitive to the potential growth rate of the kernel and number of kernels per plant. This model is able to simulate the observed rates of grain growth and leaf senescence from anthesis to physiological maturity for wheat plants grown in two CO2 concentrations. The simulated temperature response of grain growth agrees well with the experimenal observations.

Using a GLMM to estimate the somatic growth rate trend for male South African west coast rock lobster, Jasus lalandii

2004 ◽  
Vol 70 (2-3) ◽  
pp. 339-349 ◽  
Author(s):  
A. Brandão ◽  
D.S. Butterworth ◽  
S.J. Johnston ◽  
J.P. Glazer
Keyword(s):  
Growth Rate ◽  
South African ◽  
West Coast ◽  
Somatic Growth ◽  
Rock Lobster ◽  
Somatic Growth Rate

Numerical Model of Current Speed in Bojong Salawe Beach, Pangandaran West Java Province

2021 ◽  
Vol 2 (1) ◽  
pp. 17-23
Author(s):  
Subiyanto Subiyanto ◽  
Nira na Nirwa ◽  
Yuniarti Yuniarti ◽  
Yudi Nurul Ihsan ◽  
Eddy Afrianto
Keyword(s):  
Numerical Models ◽  
High Tide ◽  
Movement Pattern ◽  
Numerical Data ◽  
Current Speed ◽  
The West ◽  
Instantaneous Speed ◽  
The Difference ◽  
West Monsoon ◽  
Current Movement

The purpose of this study was to determine the hydrodynamic conditions at Bojong Salawe beach. The method used in this research is a quantitative method, where numerical data is collected to support the formation of numerical models such as wind, bathymetry, and tide data. The hydrodynamic model will be made using Mike 21 with the Flow Model FM module to determine the current movement pattern based on the data used. In the west monsoon with a maximum instantaneous speed of 0.04 - 0.08 m/s, while in the east monsoon it moves with a maximum instantaneous speed of 0,4 – 0,44 m/s. The dominant direction of current movement tends to the northeast. The results indicate the current speed during the east monsoon is higher than the west monsoon. The difference in the current speed is also influenced by the tide conditions; higher during high tide and lower during low tide. Monsoons also have a role in the current movements, though the effect is not very significant.

scholarly journals The efficacy of plant extracts on cecal amebiasis in rats

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Enerst C. Ohanu ◽  
Paul C. Inyang-Etoh
Keyword(s):  
Body Weight ◽  
Plant Extracts ◽  
Public Health Problem ◽  
Parasite Load ◽  
Negative Control ◽  
Major Public Health Problem ◽  
Cure Rate ◽  
Standard Drug ◽  
The Mean ◽  
The Difference

Amebiasis caused by <em>Entamoeba histolytica</em> is a major public health problem in tropical and subtropical countries. Treatment failure with specific chemotherapy has been reported suggesting the possibility of drug resistance. This study investigated the anti-amoebic effects of four plant extracts on cecal amebiasis in rats. The cecal amebiasis was induced by the injection of 3.0×105 troph/mL of <em>E. histolytica</em> parasite directly into the rat’s caecum. A total of 137 rats were used for these studies; five rats in each group for both positive and negative control, 15 rats in each group to test the four plant extracts and metronidazole. The infected rats were treated for cecal amebiasis using each of the four plant extracts at graded doses of 100 mg/kg, 200 mg/kg and 400 mg/kg and with metronidzole at a dose of 62.5 mg/kg,100 mg/kg and 125 mg/kg for five consecutive days. The efficacy of the four plant extracts were evaluated based on Neal’s, 1951 method. The plant extracts of Garlic, <em>Guava</em>, Pawpaw and Pumpkin at 400 mg/kg and 200 mg/kg body-weight gave a cure rate of 80%, 100%, 60%, 40% and 40%, 80%, 40%, 0%, respectively. The mean parasite count in the cecal contents of the treated rats at a dose 400 mg/kg were 18.5±1.6, 0.0±0.0, 33.3±1.8 and 49.5±4.0, respectively. The difference was statistically significant (P&lt;0.05). This study has revealed that Guava at a high dosing level (400 mg/kg body weight) is as good as the standard drug in reducing the both parasite load (probably with limited side effect).

scholarly journals Features of body weight growth in meat breeds heifers

2016 ◽  
Vol 18 (2) ◽  
Author(s):  
R. S. Oseredchuk ◽  
N. P. Babik ◽  
V. V. Fedorovych ◽  
E. I. Fedorovych ◽  
V. R. Dutka
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Weight Changes ◽  
Body Weight Changes ◽  
Relative Growth ◽  
Weight Growth ◽  
Rate Of Increase ◽  
The Difference ◽  
Tension Increase ◽  
Better Than

The data on the dynamics of body weight changes, absolute and average daily gains, frequency rate of increase in body weight, relative growth rate and intensity of body weight growth of Limousine and Volyn Meat breeds heifers. Both studied breeds characterized by different body weight at different age periods. Newborn Limousine breed heifers are weighed 2,7 kg more (P < 0.05) than Volyn Meat breed heifers; at 3 months age the difference was 8.5 kg (P < 0.05) at 6 months – 14.6 kg, at 9 month – 20.8 kg (P < 0.05), at 12 months – 25,6 kg (P < 0.05), at 15–months – 31.9 (P<0,05), and at 18 months – 23.5 kg. Total and average daily gains in animals of both breeds were the highest for a period of 3 to 6 months of age. In the period from birth to 15 months of age preference for average daily gains were in Limousine, however, the difference was statistically significant only for the period of 0 – 3 months and amounted to 63,9 g (P < 0,05). From 15 to 18 months of age Limousine slightly conceded to Volyn Meat breeds on this parameter. In animals of both breeds magnification of body weight increased with age, but over the entire period (from birth to 18 months) this parameter in Volyn Meat heifers was 0.6 times better than Limousine heifers. The coefficients of relative intensity and tension increase of body weight in animals of both breeds were highest in the period from birth to 3 months of age. With age, these indicators declined. Mainly, the advantage was in Volyn meat breed heifers, but the difference was not statistically significant.

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