scholarly journals Stability of spermatogenesis and displays of natural selection at the cellular and individual level in immature representatives of the Pelophylax esculentus complex

2016 ◽  
Vol 24 (1) ◽  
pp. 193-202
Author(s):  
O. Biriuk ◽  
O. Usova ◽  
O. Meleshko ◽  
D. Shabanov
Keyword(s):  
Parental Species ◽  
Meta Analysis ◽  
Age Groups ◽  
Normal Karyotype ◽  
Early Death ◽  
Karyological Analysis ◽  
Individual Level ◽  
Small Water ◽  
Water Frogs ◽  
Pelophylax Esculentus

Pelophylax esculentus is an interspecific hybrid which reproduces hemiclonally by crossing with the parental species (P. ridibundus or P. lessonae). The structure of hemiclonal population systems is of great interest. The majority of investigations into populations of water frogs deal with samples of mature animals, while subadults are less studied. We collected a random sample of 73 small water frogs from three localities in the Siverskyi Donets River floodplain. All frogs were measured, injected with colchicines and killed after anesthesia. We determined the species specifity, sex, age and ploidy of every individual. In addition, we measured testis length and studied the germ cells of all males by means of karyological analysis. We calculated the portion of triploids in the largest subsample from the vicinity of the Biological Station of V.N. Karazin Kharkiv National University and carried out a meta-analysis of previous publications dealing with composition of green frog samples from this locality. The proportion of triploids in our sample appeared to be approximately the same as 12 years ago. However, this proportion in our sample differed significantly from that obtained in recent samples of green frogs belonging to other age groups (adults and metamorphs) from the same locality. The share of triploids of P. esculentus is the lowest in the sample of metamorphs. This proportion increases in froglets because of early death of representatives of parental species which originated from hybrid-hybrid crossing. Then the number of triploids among adult P. esculentus individuals declines again probably because of their lower viability compared to diploids. We have revealed that subadult diploids have erythrocytes smaller than 28 microns, while triploids’ erythrocytes exceed 27 microns. Therefore, in borderline cases true ploidy could be determined only by the karyological technique. The average ratio between testis length and body length appeared to be larger in the parental species than in both diploid and triploid hybrids. Karyological analysis has revealed that P. esculentus had significantly lower portions of spermatocytes I with normal karyotype (13 bivalents) in the testis in comparison with P. ridibundus, but this value increases in adult hybrids. We suggest that increasing of spermatogenesis stability in adult frogs as opposed to subadults might be the consequence of both selection of germ cell lines in the testis and more frequent survival of individuals with stable gametogenesis. 

scholarly journals Endoparasitic helminths of water frog complex in Poland: do differences exist between the parental species Pelophylax ridibundus and Pelophylax lessonae, and their natural hybrid Pelophylax esculentus?

2011 ◽  
Vol 48 (2) ◽  
pp. 108-115 ◽  
Author(s):  
M. Popiołek ◽  
B. Rozenblut-Kościsty ◽  
M. Kot ◽  
W. Nosal ◽  
M. Ogielska
Keyword(s):  
20Th Century ◽  
Parental Species ◽  
Helminth Species ◽  
Natural Hybrid ◽  
Intensity Of Infection ◽  
Water Frog ◽  
Pelophylax Ridibundus ◽  
Water Frogs ◽  
Pelophylax Esculentus ◽  
Cosmocerca Ornata

AbstractParasitic fauna of water frogs was mainly studied in the second half of the 20th century. However, these studies were done without differentiation into species and hybrids and pooled the 3 taxa as “water frogs” or “green frogs”. The aim of this study was to make an inventory of helminth species as well as their prevalence and intensity of infection in the two parental species (Pelophylax ridibundus and P. lessonae) and the hybrid (P. esculentus) of water frogs from 3 big populations composed of hundreds or thousands of individuals inhabited natural and seminatural landscapes in Poland. Eight helminth species were found: Polystoma integerrimum, Diplodiscus subclavatus, Opisthoglyphe ranae, Gorgodera cygnoides, Haematoloechus variegatus, Oswaldocruzia filiformis, Cosmocerca ornata and Acanthocephalus ranae. The results were compared with data from other, polish and European studies. Additionally we compared the level of infection among water frog taxa.

Body size variation in hybrids among populations of European water frogs (Pelophylax esculentus complex) with different breeding systems

2020 ◽  
Vol 41 (3) ◽  
pp. 361-371
Author(s):  
Adam Hermaniuk ◽  
Magdalena Czajkowska ◽  
Anetta Borkowska ◽  
Jan R.E. Taylor
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Parental Species ◽  
Size Variation ◽  
Breeding Systems ◽  
European Water ◽  
Water Frogs ◽  
Population Type ◽  
Pelophylax Esculentus ◽  
European Water Frogs

Abstract In some populations, hybrids reproduce with a parental species by eliminating the genome of this species from their own germline and produce gametes that only contain the genome of the other parental species (sexual host). This mode of reproduction, known as hybridogenesis, leads to a conflict of interest between the two parties because the sexual host should avoid mating with the hybrid to prevent a reduction in reproductive success, whereas the hybrid depends on such matings for survival. We investigated European water frogs (Pelophylax esculentus complex), including hybrids (P. esculentus, genotype LR) and two sexual host species (P. lessonae, LL and P. ridibundus, RR). We hypothesized that to maximize fitness, hybrid males should be morphologically more similar to the sexual host that is preferred by females for successful reproduction. To test this hypothesis, we compared hybrid males in two different population types, L-E (hybrids coexist with LL) and L-E-R (hybrids coexist with both LL and RR). The latter was described in terms of genome composition, sex ratio, and mate choice preferences; the sex ratio of hybrids was significantly male-biased. We found that LR males from the L-E-R populations were significantly larger than those from the L-E, which makes them more similar to P. ridibundus, the largest species within the P. esculentus complex. We suggest that a larger body size of hybrid males may provide a reproductive advantage in the L-E-R population type, where the most common type of pair caught in the breeding season was LR males × RR females.

Age structure, size and growth rate of water frogs from central European natural Pelophylax ridibundus-Pelophylax esculentus mixed populations estimated by skeletochronology

2010 ◽  
Vol 31 (2) ◽  
pp. 239-250 ◽  
Author(s):  
Małgorzata Socha ◽  
Maria Ogielska
Keyword(s):  
Parental Species ◽  
Rana Esculenta ◽  
Breeding Sites ◽  
Central European ◽  
Water Frog ◽  
Water Frogs ◽  
Pelophylax Esculentus ◽  
Mixed Populations ◽  
The Difference ◽  
European Water Frog

AbstractCentral European water frog Pelophylax esculentus (formerly known as Rana esculenta) is a natural hybrid between P. lessonae and P. ridibundus. The hybrids reproduce by hybridogenesis and usually share populations with one of the parental species. Natural ridibundus-esculentus (R-E) mixed populations are rare. The population described herein is composed of 80% P. ridibundus and 20% P. esculentus represented by both sexes. We analyzed 159 adults and 228 juveniles. Age of adults collected from breeding sites ranged from 2 to 6 years in males and from 3 to 7 years in females of both taxa. The percentage of individuals older than 5 years was low. Average age of P. ridibundus was higher than that of P. esculentus. In P. ridibundus the average age of females was higher than that of males. In P. esculentus the difference between ages of females and males was not significant. Measurements of yearly radial growth of long bones revealed that the frogs grew intensively before reaching sexual maturity (3 years for females and 2 years for males). In the group of juveniles before I hibernation, P. esculentus were significantly bigger than P. ridibundus, however, there was no difference in body size between both taxa after I hibernation i.e., before the start of a new growth season. Mean LAG-1 diameters were significantly greater in adults P. ridibundus than in juveniles after I hibernation, but not in P. esculentus.

Age Differences in Eye Movements During Reading: Degenerative Problems or Compensatory Strategy?

2019 ◽  
Vol 24 (4) ◽  
pp. 297-311
Author(s):  
José David Moreno ◽  
José A. León ◽  
Lorena A. M. Arnal ◽  
Juan Botella
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Meta Analysis ◽  
Age Groups ◽  
Behavioral Changes ◽  
Aging Effects ◽  
Movement Data ◽  
Sentence Reading ◽  
The Difference ◽  
Eye Movements During Reading

Abstract. We report the results of a meta-analysis of 22 experiments comparing the eye movement data obtained from young ( Mage = 21 years) and old ( Mage = 73 years) readers. The data included six eye movement measures (mean gaze duration, mean fixation duration, total sentence reading time, mean number of fixations, mean number of regressions, and mean length of progressive saccade eye movements). Estimates were obtained of the typified mean difference, d, between the age groups in all six measures. The results showed positive combined effect size estimates in favor of the young adult group (between 0.54 and 3.66 in all measures), although the difference for the mean number of fixations was not significant. Young adults make in a systematic way, shorter gazes, fewer regressions, and shorter saccadic movements during reading than older adults, and they also read faster. The meta-analysis results confirm statistically the most common patterns observed in previous research; therefore, eye movements seem to be a useful tool to measure behavioral changes due to the aging process. Moreover, these results do not allow us to discard either of the two main hypotheses assessed for explaining the observed aging effects, namely neural degenerative problems and the adoption of compensatory strategies.

Effectiveness of psychological interventions to improve emotion regulation in youth - a meta-analysis

2019 ◽  
Author(s):  
Bettina Moltrecht ◽  
Jessica Deighton ◽  
Praveetha Patalay ◽  
Julian Childs
Keyword(s):  
Emotion Regulation ◽  
Emotion Dysregulation ◽  
Psychological Intervention ◽  
Meta Analysis ◽  
Age Groups ◽  
Effect Sizes ◽  
What Works ◽  
Large Heterogeneity ◽  
Larger Sample

Background: Research investigating the role of emotion regulation (ER) in the development and treatment of psychopathology has increased in recent years. Evidence suggests that an increased focus on ER in treatment can improve existing interventions. Most ER research has neglected young people, therefore the present meta-analysis summarizes the evidence for existing psychosocial intervention and their effectiveness to improve ER in youth. Methods: A systematic review and meta-analysis was conducted according to the PRISMA guidelines. Twenty-one randomized-control-trials (RCTs) assessed changes in ER following a psychological intervention in youth exhibiting various psychopathological symptoms.Results: We found moderate effect sizes for current interventions to decrease emotion dysregulation in youth (g=-.46) and small effect sizes to improve emotion regulation (g=0.36). Significant differences between studies including intervention components, ER measures and populations studied resulted in large heterogeneity. Conclusion: This is the first meta-analysis that summarizes the effectiveness for existing interventions to improve ER in youth. The results suggest that interventions can enhance ER in youth, and that these improvements correlate with improvements in psychopathology. More RCTs including larger sample sizes, different age groups and psychopathologies are needed to increase our understanding of what works for who and when.

scholarly journals Multilevel modelling and multiple group analysis of disparities in continuity of care and viral suppression among adolescents and youths living with HIV in Nigeria

2020 ◽  
Vol 5 (11) ◽  
pp. e003269
Author(s):  
Okikiolu Badejo ◽  
Christiana Noestlinger ◽  
Toyin Jolayemi ◽  
Juliette Adeola ◽  
Prosper Okonkwo ◽  
...  
Keyword(s):  
Young Adults ◽  
Viral Suppression ◽  
Group Analysis ◽  
Age Groups ◽  
Multilevel Modelling ◽  
Retention In Care ◽  
Healthcare Facilities ◽  
Individual Level ◽  
Multiple Group ◽  
Facility Level

IntroductionSubstantial disparities in care outcomes exist between different subgroups of adolescents and youths living with HIV (AYLHIV). Understanding variation in individual and health facility characteristics could be key to identifying targets for interventions to reduce these disparities. We modelled variation in AYLHIV retention in care and viral suppression, and quantified the extent to which individual and facility characteristics account for observed variations.MethodsWe included 1170 young adolescents (10–14 years), 3206 older adolescents (15–19 years) and 9151 young adults (20–24 years) who were initiated on antiretroviral therapy (ART) between January 2015 and December 2017 across 124 healthcare facilities in Nigeria. For each age group, we used multilevel modelling to partition observed variation of main outcomes (retention in care and viral suppression at 12 months after ART initiation) by individual (level one) and health facility (level two) characteristics. We used multiple group analysis to compare the effects of individual and facility characteristics across age groups.ResultsFacility characteristics explained most of the observed variance in retention in care in all the age groups, with smaller contributions from individual-level characteristics (14%–22.22% vs 0%–3.84%). For viral suppression, facility characteristics accounted for a higher proportion of variance in young adolescents (15.79%), but not in older adolescents (0%) and young adults (3.45%). Males were more likely to not be retained in care (adjusted OR (aOR)=1.28; p<0.001 young adults) and less likely to achieve viral suppression (aOR=0.69; p<0.05 older adolescent). Increasing facility-level viral load testing reduced the likelihood of non-retention in care, while baseline regimen TDF/3TC/EFV or NVP increased the likelihood of viral suppression.ConclusionsDifferences in characteristics of healthcare facilities accounted for observed disparities in retention in care and, to a lesser extent, disparities in viral suppression. An optimal combination of individual and health services approaches is, therefore, necessary to reduce disparities in the health and well-being of AYLHIV.

scholarly journals Antiphospholipid Antibodies in Sickle Cell Disease: A Systematic Review and Exploratory Meta-Analysis

2021 ◽  
Vol 27 ◽  
pp. 107602962110029
Author(s):  
Mira Merashli ◽  
Alessia Arcaro ◽  
Maria Graf ◽  
Matilde Caruso ◽  
Paul R. J. Ames ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Antiphospholipid Antibodies ◽  
Meta Analysis ◽  
Age Groups ◽  
Anticardiolipin Antibodies ◽  
Cell Disease ◽  
Pooled Prevalence ◽  
The Relationship

The relationship between antiphospholipid antibodies (aPL) and sickle cell disease (SCD) has never been systematically addressed. Our aim was to evaluate potential links between SCD and aPL in all age groups. EMBASE/PubMed was screened from inception to May 2020 and Peto odds ratios for rare events were calculated. The pooled prevalence (PP) of IgG anticardiolipin antibodies (aCL) was higher in individuals with SCD than in controls (27.9% vs 8.7%, P < 0.0001), that of IgM aCL was similar in the two groups (2.9% vs 2.7%); only individuals with SCD were positive for lupus anticoagulant (LA) (7.7% vs 0%, P < 0.0001). The PP of leg ulcers was similar between aPL positive and negative individuals (44% vs 53%) and between patients in acute crisis and stable patients (5.6% vs 7.3%). Reporting of aPL as a binary outcome and not as a titer precluded further interpretation. The results indicate that a prospective case-control study with serial measurements of a panel of aPL in SCD patients might be warranted, in order to understand further the possible pathogenic role of aPL in SCD.

scholarly journals Influenza-associated disease burden in mainland China: a systematic review and meta-analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Li ◽  
Yinzi Chen ◽  
Xiling Wang ◽  
Hongjie Yu
Keyword(s):  
Systematic Review ◽  
Publication Bias ◽  
Fixed Effects ◽  
Disease Burden ◽  
Outpatient Visit ◽  
Meta Analysis ◽  
Age Groups ◽  
Mainland China ◽  
Mortality And Morbidity ◽  
All Cause Mortality

AbstractInfluenza causes substantial morbidity and mortality. Many original studies have been carried out to estimate disease burden of influenza in mainland China, while the full disease burden has not yet been systematically reviewed. We did a systematic review and meta-analysis to assess the burden of influenza-associated mortality, hospitalization, and outpatient visit in mainland China. We searched 3 English and 4 Chinese databases with studies published from 2005 to 2019. Studies reporting population-based rates of mortality, hospitalization, or outpatient visit attributed to seasonal influenza were included in the analysis. Fixed-effects or random-effects model was used to calculate pooled estimates of influenza-associated mortality depending on the degree of heterogeneity. Meta-regression was applied to explore the sources of heterogeneity. Publication bias was assessed by funnel plots and Egger’s test. We identified 30 studies eligible for inclusion with 17, 8, 5 studies reporting mortality, hospitalization, and outpatient visit associated with influenza, respectively. The pooled influenza-associated all-cause mortality rates were 14.33 and 122.79 per 100,000 persons for all ages and ≥ 65 years age groups, respectively. Studies were highly heterogeneous in aspects of age group, cause of death, statistical model, geographic location, and study period, and these factors could explain 60.14% of the heterogeneity in influenza-associated mortality. No significant publication bias existed in estimates of influenza-associated all-cause mortality. Children aged < 5 years were observed with the highest rates of influenza-associated hospitalizations and ILI outpatient visits. People aged ≥ 65 years and < 5 years contribute mostly to mortality and morbidity burden due to influenza, which calls for targeted vaccination policy for older adults and younger children in mainland China.

Macro-level Criminological Perspectives and School Delinquency: A Meta-analysis

2021 ◽  
pp. 0044118X2110223
Author(s):  
Natasha Pusch
Keyword(s):  
Social Cohesion ◽  
Meta Analysis ◽  
School Level ◽  
Effect Sizes ◽  
Macro Level ◽  
Future Research ◽  
Concentrated Disadvantage ◽  
Individual Level ◽  
School Differences ◽  
Academic Implications

School delinquency in public elementary, middle, and high schools has decreased in recent years, but is still a major issue that has negative mental health and academic implications for adolescents. Although research has focused on both individual-level and school-level explanations of school delinquency, it is not yet clear which macro-level criminological perspectives best explains it. Using 656 effect sizes nested within 75 studies and 30 unique datasets, this study addresses two questions using meta-analytic methods: Which macro-level criminological perspectives explain between-school differences in delinquency? Are effect sizes invariant across samples and research design? Results indicate that only concentrated disadvantage and social cohesion are significantly related to school delinquency. With the exception of concentrated disadvantage, effects are homogenous. This suggests that some school-level explanations are useful and future research should not exclude these factors. Practical implications suggest that improving social cohesion in schools may be more effective at preventing violence than target-hardening efforts.

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