scholarly journals Demasculinization of male guppies increases resistance to a common and harmful ectoparasite

Parasitology ◽  
2015 ◽  
Vol 142 (13) ◽  
pp. 1647-1655 ◽  
Author(s):  
FELIPE DARGENT ◽  
ADAM R. REDDON ◽  
WILLIAM T. SWANEY ◽  
GREGOR F. FUSSMANN ◽  
SIMON M. READER ◽  
...  
Keyword(s):  
Poecilia Reticulata ◽  
Gonadal Steroids ◽  
Measurable Effect ◽  
Immunomodulatory Effects ◽  
Defence Mechanisms ◽  
Androgen Receptor Antagonist ◽  
Host Sex ◽  
Evolution Of Resistance ◽  
Males And Females ◽  
Over Time

SUMMARYParasites are detrimental to host fitness and therefore should strongly select for host defence mechanisms. Yet, hosts vary considerably in their observed parasite loads. One notable source of inter-individual variation in parasitism is host sex. Such variation could be caused by the immunomodulatory effects of gonadal steroids. Here we assess the influence of gonadal steroids on the ability of guppies (Poecilia reticulata) to defend themselves against a common and deleterious parasite (Gyrodactylus turnbulli). Adult male guppies underwent 31 days of artificial demasculinization with the androgen receptor-antagonist flutamide, or feminization with a combination of flutamide and the synthetic oestrogen 17 β-estradiol, and their parasite loads were compared over time to untreated males and females. Both demasculinized and feminized male guppies had lower G. turnbulli loads than the untreated males and females, but this effect appeared to be mainly the result of demasculinization, with feminization having no additional measurable effect. Furthermore, demasculinized males, feminized males and untreated females all suffered lower Gyrodactylus-induced mortality than untreated males. Together, these results suggest that androgens reduce the ability of guppies to control parasite loads, and modulate resistance to and survival from infection. We discuss the relevance of these findings for understanding constraints on the evolution of resistance in guppies and other vertebrates.

Seasonal Variation of Suicide in the City of São Paulo, Brazil, 1996–2010

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe
Keyword(s):  
Seasonal Pattern ◽  
Total Sample ◽  
Sao Paulo ◽  
Seasonal Patterns ◽  
São Paulo ◽  
Health Statistics ◽  
Males And Females ◽  
June July ◽  
The City ◽  
Over Time

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.

scholarly journals A Retrospective Study on Amoxicillin Susceptibility in Severe Haemophilus influenzae Pneumonia

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Pierre Danneels ◽  
Maria Concetta Postorino ◽  
Alessio Strazzulla ◽  
Nabil Belfeki ◽  
Aurelia Pitch ◽  
...  
Keyword(s):  
Risk Factors ◽  
Haemophilus Influenzae ◽  
Severe Pneumonia ◽  
Chronic Obstructive ◽  
Ventilator Associated Pneumonia ◽  
Obstructive Pulmonary Disease ◽  
Amoxicillin Clavulanic Acid ◽  
Evolution Of Resistance ◽  
Resistant Strains ◽  
Over Time

Introduction. Treatment of Haemophilus influenzae (Hi) pneumonia is on concern because resistance to amoxicillin is largely diffused. This study describes the evolution of resistance to amoxicillin and amoxicillin/clavulanic acid (AMC) in Hi isolates and characteristics of patients with Hi severe pneumonia. Methods. A monocentric retrospective observational study including patients from 2008 to 2017 with severe pneumonia hospitalized in ICU. Evolution of amoxicillin and AMC susceptibility was showed. Characteristics of patients with Hi pneumonia were compared to characteristics of patients with Streptococcus pneumoniae (Sp) pneumonia, as reference. Risk factors for amoxicillin resistance in Hi were investigated. Results. Overall, 113 patients with Hi and 132 with Sp pneumonia were included. The percentages of AMC resistance among Hi strains decreased over the years (from 10% in 2008-2009 to 0% in 2016-2017) while resistance to amoxicillin remained stable at 20%. Also, percentages of Sp resistant strains for amoxicillin decreased over years (from 25% to 3%). Patients with Hi pneumonia experienced higher prevalence of bronchitis (18% vs. 8%, p=0.02, chronic obstructive pulmonary disease (43% vs. 30% p=0.03), HAP (18% vs. 7%, p=0.01, ventilator-associated pneumonia (27% vs. 17%, p=0.04, and longer duration of mechanical ventilation (8 days vs. 6 days, p=0.04) than patients with Sp pneumonia. Patients with Sp pneumonia had more frequently local complications than patients with Hi pneumonia (17% vs. 7%, p=0.03). De-escalation of antibiotics was more frequent in patients with Sp than in patients with Hi (67% vs. 53%, p=0.03). No risk factors were associated with amoxicillin resistance among patients with Hi pneumonia. Conclusions. Amoxicillin resistance was stable over time, but no risk factors were detected. AMC resistance was extremely low, suggesting that AMC could be used for empiric treatment of Hi pneumonia, as well as other molecules, namely, cephalosporins. Patients with Hi pneumonia had more pulmonary comorbidities and severe diseases than patients with Sp pneumonia.

Gonadal steroids effect similar regulation of gonadotrophin subunit mRNA expression in both male and female rats

1992 ◽  
Vol 132 (1) ◽  
pp. 39-45 ◽  
Author(s):  
A. C. Dalkin ◽  
S. J. Paul ◽  
D. J. Haisenleder ◽  
G. A. Ortolano ◽  
M. Yasin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Steady State ◽  
Gnrh Antagonist ◽  
Gonadal Steroids ◽  
Female Rats ◽  
Plasma Testosterone ◽  
Subunit Gene ◽  
Gnrh Secretion ◽  
Male And Female Rats ◽  
Males And Females

ABSTRACT Gonadal steroids can act both indirectly via gonadotrophin-releasing hormone (GnRH) and directly on the pituitary to regulate gonadotrophin subunit gene expression. Recent studies to assess a possible direct action at the pituitary have shown that testosterone, when given to males in the absence of endogenous GnRH action, selectively increases FSH-β mRNA concentrations. Conversely, in females, oestradiol appears to regulate gonadotrophin subunit mRNAs primarily via GnRH. The present study was designed to determine whether these differing results reflect specific actions of the gonadal steroids themselves or different responses of the pituitary gonadotroph cells in males and females. Rats which had been castrated 7 days earlier were given silicone elastomer implants (s.c.) containing oestradiol (plasma oestradiol 68 ± 4 ng/l) in males or testosterone (plasma testosterone 3·5 ± 0·3 μg/l) in females in the absence or presence of a GnRH antagonist. Seven days later pituitaries were removed and steady-state mRNA concentrations measured by dotblot hybridization. In males, oestradiol reduced LH-β and FSH-β but not α mRNA. The antagonist reduced levels of all three subunit mRNAs in males and the addition of oestradiol had no further effect, suggesting that oestradiol regulates gonadotrophin subunit gene expression in males by suppressing GnRH secretion. In females, testosterone reduced all three subunit mRNAs though FSH-β remained threefold higher than in intact animals. The GnRH antagonist was as effective as testosterone alone and reduced α and LH-β to levels found in intact animals. FSH-β mRNA was partially reduced by antagonist alone in ovariectomized females but the addition of testosterone increased FSH-β twofold versus antagonist alone (as has been observed in males). These findings, together with earlier data, suggest that testosterone increased FSH-β twofold versus antagonist alone (as has been observed in males). These findings, together with earlier data, suggest that testosterone reduces gonadotrophin subunit mRNAs by inhibiting GnRH secretion and also acts directly on the gonadotroph to increase steady-state FSH-β mRNA concentrations in both males and females. Journal of Endocrinology (1992) 132, 39–45

scholarly journals All sites but skin cancer incidences analyzed worldwide by sex, age, and skin type over time (1955-2007), advancing age, and UVB dose reveals important carcinogenic drivers

2017 ◽  
Vol 3 (2) ◽  
pp. 65
Author(s):  
Dianne E. Godar ◽  
Rossen Gurov ◽  
Stephen J. Merrill
Keyword(s):  
Human Papillomavirus ◽  
Skin Cancer ◽  
Vitamin D3 ◽  
Age Groups ◽  
Hair Follicles ◽  
Skin Type ◽  
European Ancestry ◽  
Developed Country ◽  
Males And Females ◽  
Over Time

Because we observed increasing incidences over time, advancing age, higher estrogen levels, decreasing UVB (290-315 nm) doses, or lower vitamin D3, and Human Papillomavirus hiding in immune-privileged sites of hair follicles play roles in melanoma, we wondered if the majority of cancers might have similar carcinogenic drivers. To investigate this possibility, we performed worldwide analysis of all sites but skin cancer over time (1955-2007), advancing age, and UVB doses for males and females with all skin types and ages (0-85+) and in five age groups using IARC data. To investigate Human Papillomavirus’s role, we analyzed the incidences of breast, prostate, and colon cancers in a developed country with European ancestry (New Zealand) having high amounts of androgenic hair and a developing country with Asian ancestry (India) having low amounts of androgenic hair. To potentially add epidemiology to the already established role of estrogen in cancer, we analyzed males and females in various countries around the world using the incidence of breast cancer (> 70 yr.) as an established indicator of estrogen levels. The analysis reveals cancer incidences are steadily increasing over time in developed but not developing countries regardless of skin type. Only US white, but not black, breast, prostate, and colon cancer incidences in the oldest age group significantly decreased with increasing UVB dose suggesting a role for vitamin D3. The data suggests the carcinogenic drivers in many cancers are estrogen, increasing age (or reactive oxygen species), decreasing vitamin D3 levels, and persistence of Human Papillomavirus infection in immune-privileged sites.

scholarly journals Intraspecific ecomorphological variations in Poecilia reticulata (Actinopterygii, Cyprinodontiformes): comparing populations of distinct environments

2015 ◽  
Vol 105 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Fábio T. Mise ◽  
Fagner de Souza ◽  
João P. A. Pagotto ◽  
Erivelto Goulart
Keyword(s):  
Poecilia Reticulata ◽  
Principal Component ◽  
Water Current ◽  
Way Of Life ◽  
Morphological Variations ◽  
Current Availability ◽  
Environment Type ◽  
Morphological Variables ◽  
Males And Females ◽  
Morphological Differences

ABSTRACT Morphological variations, according to the principles of ecomorphology, can be related to different aspects of the organism way of life, such as occupation of habitats and feeding behavior. The present study sought to examine the intraspecific variation in two populations of Poecilia reticulata Peters, 1859, that occur in two types of environments, a lotic (Maringá Stream) and a lentic (Jaboti Lake). Due to a marked sexual dimorphism, males and females were analyzed separately. Thus, the proposed hypotheses were that the populations that occur in distinct environments present morphological differences. The morphological variables were obtained using morphometric measurements and the ecomorphological indexes. The data were summarized in a Principal Component Analysis (PCA). A Multivariate Analysis of Variance (Manova) was made to verify significant differences in morphology between the populations. Males and females showed similar ecomorphological patterns according to the environment they occur. In general the population from Maringá Stream had fins with major areas, and the Jaboti Lake population eyes located more dorsally. Additionally, others morphological differences such as wider mouth of the males from Maringá Stream, wider heads on Jaboti Lake females and more protractible mouths on males from Jaboti Lake suggest a set of environmental variables that can possibly influence the ecomorphological patterns of the populations, as the water current, availability of food resources and predation. In summary, the initial hypotheses could be confirmed, evidencing the occurrence of distinct ecomorphotypes in the same species according to the environment type.

Changes in Drug Involvement: A Longitudinal Study of Childhood and Adolescent Determinants

1989 ◽  
Vol 65 (3) ◽  
pp. 707-726 ◽  
Author(s):  
Judith S. Brook ◽  
Martin Whiteman ◽  
Ann Scovell Gordon ◽  
Patricia Cohen
Keyword(s):  
Interactive Effects ◽  
Early Adolescent ◽  
Personality Factors ◽  
Structured Interviews ◽  
White Males ◽  
Drug Involvement ◽  
Lower Drug ◽  
Males And Females ◽  
And Behavior ◽  
Over Time

Previous research has identified childhood and adolescent personality determinants of early adolescent drug involvement. The purpose of the present study was to examine the determinants of increased involvement over time and to compare these results with previous findings regarding early involvement. Data were available on 654 white males and females at three points, Time 1 (T1) at ages 1–10 yr., Time 2 (T2) at ages 9–18 yr., and Time 3 (T3) at ages 11–20 yr. The subjects (at T2 and T3) and their mothers (at all three points) were given structured interviews assessing the child's personality and behavior. Results indicated that T1 traits of conventionality and emotional control were associated with similar traits at T2, which, in turn, were related to lower drug involvement over time (T2 and T3). Interactive effects indicated first that T2 adolescent protective (nondrug-conducive) factors weakened the effect of childhood-risk (drug-conducive) characteristics resulting in lower drug involvement. Second, high levels of earlier drug use interacted synergistically with personality risk leading to increased levels of involvement. Over-all, the personality factors implicated in increased involvement were similar to those related to earlier involvement.

scholarly journals Extreme fertilization bias towards freshly inseminated sperm in a species exhibiting prolonged female sperm storage

2018 ◽  
Vol 5 (3) ◽  
pp. 172195 ◽  
Author(s):  
Clelia Gasparini ◽  
Emma Daymond ◽  
Jonathan P. Evans
Keyword(s):  
Artificial Insemination ◽  
Poecilia Reticulata ◽  
Sperm Storage ◽  
Sperm Precedence ◽  
Control Potential ◽  
Complete Dominance ◽  
Poeciliid Fish ◽  
Behavioural Interactions ◽  
Males And Females ◽  
Reproductive Cycles

The storage of sperm by females across successive reproductive cycles is well documented in internal fertilizers, yet the fate of stored sperm when they compete with ‘new’ sperm to fertilize a female's eggs has rarely been considered. This gap in our understanding is likely due to the logistical difficulties of controlling behavioural interactions during or after mating, which in turn may influence how many sperm are inseminated and how stored sperm are ultimately used during successive bouts of sperm competition with freshly inseminated sperm. Here, we use artificial insemination (AI) in guppies ( Poecilia reticulata ), a polyandrous live-bearing poeciliid fish exhibiting prolonged sperm storage by females, to overcome these challenges. The use of AI enables us to control potential differential maternal effects (e.g. behaviourally mediated cryptic female choice) and specifically test for post-copulatory paternity biases that favour either stored or fresh sperm when they compete to fertilize eggs. Our paternity analyses revealed the almost complete dominance of freshly inseminated sperm over stored sperm, supporting previous studies reporting similar patterns following natural matings across successive brood cycles. However, our use of AI, which excluded behavioural interactions between males and females, most likely generated a far stronger pattern of fresh sperm precedence compared with those reported in previous studies, possibly implicating ‘cryptic' forms of selection by females that may sometimes bolster the success of stored sperm.

scholarly journals Depressive vulnerability, stressful life events and episode onset of major depression: a longitudinal model

2016 ◽  
Vol 46 (9) ◽  
pp. 1865-1874 ◽  
Author(s):  
K. S. Kendler ◽  
C. O. Gardner
Keyword(s):  
Major Depression ◽  
Life Events ◽  
Stressful Life Events ◽  
Stressful Life ◽  
Equation Modeling ◽  
Parameter Estimates ◽  
Males And Females ◽  
Depressive Episodes ◽  
Over Time ◽  
Depressive Vulnerability

BackgroundThe nature of the relationship between depressive vulnerability (DV) and acute adversity in the etiology of major depression (MD) remains poorly understood.MethodStressful life events (SLEs) and MD onsets in the last year were assessed at four waves in cohort 1 (females) and at two waves in cohort 2 (males and females) from the Virginia Adult Twin Study. Structural equation modeling was conducted in Mplus.ResultsIn cohort 1, DV was strongly indexed by depressive episodes over the four waves (paths from +0.72 to 0.79) and predicted by SLEs in the month of their occurrence (+0.31 to 0.36). Wave-specific DV was associated both with stable DV (+0.29 to 0.33) and by forward transmission of DV from the preceding wave (+0.33 to 0.36). SLEs were predicted by stable DV (+0.29) and from SLEs in the preceding month (+0.06). As the cohort aged, MD onsets were better indexed by DV and more poorly predicted by SLEs. Parameter estimates were similar in males and females from cohort 2. In individuals with prior depressive episodes, the association between MD onset and SLEs was weakened while the prediction of SLEs from DV was substantially strengthened. We found no evidence for ‘reverse causation’ from MD episodes to SLEs.ConclusionThe interrelationship between DV and acute adversity in the etiology of MD is complex and temporally dynamic. DV impacts on MD risk both directly and indirectly through selection into high stress environments. Over time, depressive episodes become more autonomous. Both DV and SLEs transmit forward over time and therefore form clear targets for intervention.

scholarly journals Sexually dimorphic recombination can facilitate the establishment of sexually antagonistic polymorphisms in guppies

2018 ◽  
Author(s):  
Roberta Bergero ◽  
Jim Gardner ◽  
Beth Bader ◽  
Lengxob Yong ◽  
Deborah Charlesworth
Keyword(s):  
Sex Chromosomes ◽  
Poecilia Reticulata ◽  
Common Ancestor ◽  
Sex Chromosome ◽  
Empirical Support ◽  
Male Meiosis ◽  
Sexually Dimorphic ◽  
Sex Linkage ◽  
Recombination Suppression ◽  
Males And Females

Summary/AbstractRecombination suppression between sex chromosomes is often stated to evolve in response to polymorphisms for mutations that affect fitness of males and females in opposite directions (sexually antagonistic, or SA, mutations), but direct empirical support is lacking. The sex chromosomes of the fish Poecilia reticulata (the guppy) carry SA polymorphisms, making them excellent for testing this hypothesis for the evolution of sex linkage. We resequenced genomes of male and female guppies and, unexpectedly, found that variants on the sex chromosome indicate no extensive region with fully sex-linked genotypes, though many variants show strong evidence for partial sex linkage. We present genetic mapping results that help understand the evolution of the guppy sex chromosome pair. We find very different distributions of crossing over in the two sexes, with recombination events in male meiosis detected only at the tips of the chromosomes. The guppy may exemplify a route for sex chromosome evolution in which low recombination in males, likely evolved in a common ancestor, has facilitated the establishment of sexually antagonistic polymorphisms.

scholarly journals Effect of exposure time of pregnant females guppies, Poecilia reticulata Peters, in 17a-methyltestosterone solution on sex ratio of their offsprings

2007 ◽  
Vol 1 (1) ◽  
pp. 47
Author(s):  
M. Zairin Junior ◽  
A. Yunianti ◽  
R.R.S.P.S. Dewi ◽  
Kusman Sumawidjaja
Keyword(s):  
Sex Ratio ◽  
Exposure Time ◽  
Treatment Duration ◽  
Poecilia Reticulata ◽  
Female Offspring ◽  
Control Group ◽  
Time Interval ◽  
Water Flea ◽  
Pregnant Females ◽  
Males And Females

<p>ABSTRACT</p><p>This experiment was carried out to study the effect of female broodstocks immersion in 17amethyltestosterone (MT) solution on sex ratio of their offspring, Three-months old males and females were paired to mate in aquaria for four days.  Broodstocks were fed with frozen blood worm and water flea 2-3 tii-nes daily.  Twelve days after mating, female broodstock were treated by immersing in 2 mg/1 MT solution for 0. 6, 12, 24 and 48 hours.  Birthed guppy babies were collected and reared separately from their parents.  During the rearing period, the babies were fed with artemia nauplius and silkworm until identification for male and female.  Percentage of female offspring in control group were higher than those of male.  Exposure of pregnant females to MT solution for 0, 6, 12, 24, and 48 hours resulted in 42, 1'/o, 51%, 84,6%, 1 00%, dan 100% of males offspring, respectively.  The best result was obtained from 24 hours treatment.  Longer treatment duration tend to shorten time interval between treatment and birth. Key words :  Guppy, 17(x-methyltestosterone, exposure time, broodstock immersion, sex ratio   ABSTRAK Penefitian ini bertuiuan untuk mengetahui pengaruh lama waktu perendaman induk di dalam larutan hormon 17a-metiltestosteron (MT) terhadap nisbah kelamin ikan gapi.  Induk Ikan gapi berumur tiga bulan dikawinkan berpasangan di dalam akuarium selama empat hari Induk diberi pakan cuk merah beku dan kutu air dengan frekuensi 2-3 kali sehari.  Dua belas hari setelah masa perkawinan, induk betina diberi perlakuan berupa perendaman di dalam larutan MT 2 mg/1 selama 0 (kontrol), 6, 12, 24, dan 48 jam.  Anak-anak ikan gapi yang baru lahir dipelihara terpisah dari induknya.  Selama masa pemeliharaan, anak ikan gapi diberi pakan nauplius artemia dan cacing rambut.  Pemeliharaan berlangsung sampai jenis kelamin anak ikan gapi dapat diidentifikasi.  Persentase anak ikan gapi betina pada semua ulangan kontrol lebih tinggi daripada .iantan dengan perbandingan persentase rata-rata 57,9%: 42,1%.  Adapun pada lama waktu perendaman 0, 6, 12, 24, dan 48 jam, menghasilkan persentase anak ikan gapi berfenotip jantan berturut-turut sebesar 42,1%, 51%, 84,6%, 100%, dan 100%.  Lama waktu perendaman terbaik adalah 24 jam.  Selain itu terdapat kecenderungan bahwa semakin lama waktu perendaman semakin cepat kelahirannya. Kata kunci :  Ikan gapi, 17ot-metiltestosteron, lama perendaman, perendaman induk, nisbah kelamin</p>

Sign in / Sign up

Export Citation Format

Share Document