Isolation and inheritance of microsatellite loci in the Dungeness crab (Brachyura: Cancridae: Cancer magister)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Pamela C Jensen ◽  
Paul Bentzen

The isolation, PCR amplification, and descriptive statistics of six microsatellite loci are described for the Dungeness crab, Cancer magister. Also reported is the inheritance of these loci in two families obtained from artificial crosses in the laboratory. All six loci conform to expectations under Mendelian inheritance and there is no evidence for linkage between any of the loci. Allelic size ranges for three of the loci are relatively large, ranging from 135–357 bp between the smallest and largest allele detected at that locus. At two of these loci upper allelic drop out (non-amplification of the larger allele in a heterozygous individual) can be problematic for scoring. Results from cross-species amplification in nine congeners are summarized. These loci will be valuable in studies requiring high-resolution genetic markers in Dungeness crabs and related species.Key words: Cancer magister, microsatellite, Mendelian Inheritance, cross species amplification, Brachyura.

2001 ◽  
Vol 31 (12) ◽  
pp. 2248-2251 ◽  
Author(s):  
Y Nakao ◽  
H Iwata ◽  
A Matsumoto ◽  
Y Tsumura ◽  
N Tomaru

Nine microsatellite loci in hinoki, Chamaecyparis obtusa (Sieb. et Zucc.) Endl., were identified and characterized. A genomic library, developed using enrichment with magnetic beads, was screened to identify microsatellite repeats (CT/AG). The microsatellite loci, where the alleles were segregated, displayed codominant Mendelian inheritance. Genetic analysis of 16 plus trees and two unrelated individuals of Chamaecyparis obtusa revealed that all loci were highly polymorphic, with an average of 10.3 alleles per locus, and an average gene diversity of 0.77. The applicability of these microsatellite loci was also tested in other species of the Cupressaceae and in Cryptomeria japonica (L.f.) D. Don (Taxodiaceae, a family closely related to Cupressaceae). Polymerase chain reaction (PCR) amplification was successful for about half of the loci of the species in the genus Chamaecyparis. However, the PCR amplification patterns of the 11 species of Cupressaceae showed no clear correlations with their molecular phylogeny. The highly polymorphic microsatellite loci in Chamaecyparis obtusa, identified here, will be useful in studies of hinoki breeding and population genetics.


1989 ◽  
Vol 46 (9) ◽  
pp. 1600-1608 ◽  
Author(s):  
Barry D. Smith ◽  
Glen S. Jamieson

The abundance and size frequency distribution (SFD) of Dungeness crabs (Cancer magister) within traps varies with soak time. Such bias in catch rates was reduced using a standardization model that corrected for (1) changes in bait effectiveness over time and (2) agonistic interactions between crabs within traps and those attempting entry. The model estimated the entry and exit of crabs based on the results of trapping experiments specifically designed to (1) emphasize the above two processes and (2) estimate escapement rates from traps for crabs of different sizes. Results clearly indicated the importance of these two processes in modifying trap contents over time, and led to the introduction of the term 'virtual catch rate' (VCR), defined as the rate at which crabs would enter a trap if catch rates did not change with increasing soak time. VCRs are not observed in practice except perhaps for very short soak times, but can be estimated from trap samples by incorporating the aforementioned processes into a standardization model. We found VCR to be a better index of abundance than mean daily catch per trap, and believe it may have utility for other trap fisheries.


2008 ◽  
Vol 27 (4) ◽  
pp. 901-906 ◽  
Author(s):  
Terry D. Beacham ◽  
Janine Supernault ◽  
Kristina M. Miller

2021 ◽  
Author(s):  
Helene Schroé ◽  
Geert Crombez ◽  
Ilse De Bourdeaudhuij ◽  
Delfien Van Dyck

BACKGROUND E- and m-health interventions have gained momentum to change health behaviours such as physical activity (PA) and sedentary behaviour (SB). Although these interventions show promising results in terms of behaviour change, they still suffer from high attrition rates, resulting in a lower potential and reachability. In order to reduce attrition rates in the future, there is a need to investigate the reasons why individuals stop using e- and m-health interventions. Certain demographic variables have already been related to attrition in e- and m-health interventions, however the role of psychosocial determinants of behaviour change as predictors of attrition has not yet been fully explored. OBJECTIVE The aim of this study was to examine when, which and why users stop using an e- and m-health intervention. In particular, we aimed to investigate whether psychosocial determinants of behaviour change were predictors for attrition. METHODS The sample consisted of 473 healthy adults who participated in the e-and m-health intervention ‘MyPlan 2.0’ to promote PA or reduce SB. The intervention was developed using the Health Action Process Approach (HAPA) model, which describes psychosocial determinants that guide individuals in changing their behaviour. If participants stopped with the intervention, a questionnaire with eight question concerning attrition was sent by email. To analyze when users stopped using the intervention, descriptive statistics were used per part of the intervention (including pre- and post-test measurements, and 5 website sessions). To analyze which users stopped using the intervention, demographic variables, behavioural status and HAPA-based psychosocial determinants at pre-test measurement were investigated as potential predictors of attrition using logistic regression models. To analyze why users stopped using the intervention, descriptive statistics of answers to the attrition related questionnaire were used. RESULTS The study demonstrated that 227 of the 473 (47,9%) participants stopped using the intervention, and drop out occurred mainly in the beginning of the intervention. The results seem to indicate that gender and participants’ scores on the psychosocial determinants action planning, coping planning and self-monitoring were predictors of first session, third session and/or whole intervention completion. The most endorsed reasons to stop with the intervention were the time-consuming nature of questionnaires, not having time, dissatisfaction with the content of the intervention, technical problems, already meeting the guidelines for PA/SB, and to a lesser extent the experience of medical/emotional problems. CONCLUSIONS This study provides some directions for future studies. To decrease attrition, it will be important to personalise interventions on different levels, questionnaires (either for research purposes or tailoring) should be kept to a minimum especially in the beginning of interventions by for example using objective monitoring devices, and technical aspects of e-and m-health interventions should be thoroughly tested in advance.


2012 ◽  
Vol 6 (6) ◽  
pp. 749-761 ◽  
Author(s):  
Adele A. Mitchell ◽  
Jeannie Tamariz ◽  
Kathleen O’Connell ◽  
Nubia Ducasse ◽  
Zoran Budimlija ◽  
...  

1979 ◽  
Vol 80 (1) ◽  
pp. 271-285 ◽  
Author(s):  
B. R. McMAHON ◽  
D. G. McDONALD ◽  
C. M. WOOD

Scaphognathite and heart-pumping frequencies, ventilation volume, cardiac output, oxygen uptake and oxygen transport by haemolymph have been studied in unrestrained Dungeness crabs (Cancer magister) before, immediately after, and during recovery from 20 min of enforced exhausting activity. Exercise increased oxygen uptake 4-fold. This increase was achieved by more than 2-fold elevation of both ventilation volume and cardiac output and by greater participation of haemocyanin in oxygen delivery. The elevated ventilation volume resulted entirely from an increase in scaphognathite pumping frequency, while the rise in cardiac output resulted largely from increase in stroke volume. Prior to exercise haemocyanin accounts for less than 50% of the oxygen delivered to the tissues. Following exercise this increases to over 80%, the additional oxygen release being mediated by a depression of prebranchial oxygen tension and a substantial Bohr effect resulting from build up of lactate ion in the haemolymph and subsequent fall in pH. These changes allowed % oxygen extraction from branchial water to be maintained at 28% despite a 2-fold increase in ventilation volume, and allowed an increase in %. oxygen extraction by the tissues. Despite these changes oxygen supply fell below demand during exercise, and considerable anaerobic metabolism resulted, as evidenced by a 9-fold increase in haemolymph lactate concentration. The resulting oxygen debt required 8–24 h for repayment. Aerobic metabolic scope, and mechanisms of increasing oxygen uptake and transport in this crab are compared with those of a range of fish species.


1979 ◽  
Vol 79 (1) ◽  
pp. 47-58
Author(s):  
D. G. McDONALD ◽  
B. R. McMAHON ◽  
C. M. WOOD

Enforced activity causes a marked depression of haemofymph pH in Cancer magister. Both lactate concentration and PCOCO2 of the haemolymph are elevated immediately following exercise but resting PCOCO2 is restored within 30 min whereas resting lactate levels are not restored for at least 8 h. The haemolymph acid-base disturbance is caused largely by elevated haemolymph lactate levels but a Davenport analysis based on measurements of pH and total CO2 reveals a marked discrepancy between the amount of metabolic acid buffered by the haemolymph and the lactate anion concentration. This appears due to a more rapid release of lactate from the tissues than H+ ions produced with lactate.


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