scholarly journals High progesterone during avian meiosis biases sex ratios toward females

2005 ◽  
Vol 1 (2) ◽  
pp. 215-218 ◽  
Author(s):  
Stephanie M Correa ◽  
Elizabeth Adkins-Regan ◽  
Patricia A Johnson
Keyword(s):  
Sex Chromosome ◽  
Sex Ratios ◽  
Polar Body ◽  
Critical Time ◽  
The Other ◽  
Control Group ◽  
Steroid Production ◽  
Primary Sex Ratio ◽  
Heterogametic Sex ◽  
Meiosis I

Evidence of altered primary sex ratios in birds shows that mothers can manipulate the sex of their offspring before oviposition. In birds, females are the heterogametic sex (ZW) and males are homogametic (ZZ). Sex is determined in the first meiotic division, when one sex chromosome is retained in the oocyte and the other segregates to the polar body. Altered primary sex ratios suggest that birds may be capable of biasing the segregation of sex chromosomes during meiosis I. During the time of meiosis I, follicular steroid production is limited primarily to progesterone (P4). We experimentally manipulated the levels of P4 in female domestic chickens during the approximate time of meiosis I. We advanced the ovulation of the first egg of a sequence (or clutch) with a subcutaneous injection of P4. We found a significant effect of P4 dose on the sex of the resulting egg. The high progesterone group produced 25% males whereas the low progesterone group produced 61% males and the control group produced 63% males in the first ovulation of the sequence. We propose that variation in maternal progesterone during the critical time for genetic sex determination is the mechanism for primary sex ratio manipulation in birds.

scholarly journals The sex with the reduced sex chromosome dies earlier: a comparison across the tree of life

2020 ◽  
Vol 16 (3) ◽  
pp. 20190867 ◽  
Author(s):  
Zoe A. Xirocostas ◽  
Susan E. Everingham ◽  
Angela T. Moles
Keyword(s):  
Sex Chromosome ◽  
Meta Analysis ◽  
Chromosome Morphology ◽  
Tree Of Life ◽  
The Other ◽  
Deleterious Mutations ◽  
Male And Female ◽  
Fundamental Understanding ◽  
Female Longevity ◽  
Heterogametic Sex

Many taxa show substantial differences in lifespan between the sexes. However, these differences are not always in the same direction. In mammals, females tend to live longer than males, while in birds, males tend to live longer than females. One possible explanation for these differences in lifespan is the unguarded X hypothesis, which suggests that the reduced or absent chromosome in the heterogametic sex (e.g. the Y chromosome in mammals and the W chromosome in birds) exposes recessive deleterious mutations on the other sex chromosome. While the unguarded X hypothesis is intuitively appealing, it had never been subject to a broad test. We compiled male and female longevity data for 229 species spanning 99 families, 38 orders and eight classes across the tree of life. Consistent with the unguarded X hypothesis, a meta-analysis showed that the homogametic sex, on average, lives 17.6% longer than the heterogametic sex. Surprisingly, we found substantial differences in lifespan dimorphism between female heterogametic species (in which the homogametic sex lives 7.1% longer) and male heterogametic species (in which the homogametic sex lives 20.9% longer). Our findings demonstrate the importance of considering chromosome morphology in addition to sexual selection and environment as potential drivers of sexual dimorphism, and advance our fundamental understanding of the mechanisms that shape an organism's lifespan.

XIV.—The Genetical and Mechanical Properties of the Sex Chromosome. VI. Hexacentrus mundus

1940 ◽  
Vol 60 (2) ◽  
pp. 174-181
Author(s):  
P. C. Koller
Keyword(s):  
Mechanical Properties ◽  
X Chromosome ◽  
Meiotic Division ◽  
Sex Chromosome ◽  
The Other ◽  
Single Sex ◽  
Heterogametic Sex

Cytological studies carried out by McClung (1905, 1914) on various species of Orthoptera have shown that the male is the heterogametic sex. The male has only one X-chromosome, whereas the female has two. During spermatogenesis two kinds of gametes are produced, one with the X-chromosome and the other without it. It was also found that the segregation of the single sex chromosome takes place at first meiotic anaphase. The present paper describes the sex chromosome of the male Hexacentrus mundus Walker, from India. During the meiotic division this chromosome exhibits peculiarities which it is believed have not hitherto been seen in any species of the Orthopteræ.

Detection and Assessment of Interleukin 6 in Irreversible Pulp Inflamation

2017 ◽  
Vol 68 (2) ◽  
pp. 323-327
Author(s):  
Cristian Levente Giuroiu ◽  
Maria Vataman ◽  
Gabriel Melian ◽  
Dragos Bularda ◽  
Ludmila Lozneanu ◽  
...  
Keyword(s):  
Dental Caries ◽  
Interleukin 6 ◽  
Dental Pulp ◽  
The Other ◽  
Control Group ◽  
Study Group ◽  
Pulp Tissue ◽  
Immunohistochemical Technique ◽  
Systemic Distribution ◽  
Cell Zone

The study aimed to assess the number, localization and distribution of interleukin 6 (IL-6) positive cells in healthy pulp, acute and chronic pulpitis. The study group included 48 patients aged between 18-72, treated in University of Medicine and Pharmacy Grigore T. Popa Iasi, Romania. The pulpectomy was performed on 42 patients diagnosed with acute and chronic pulpitis. The other 6 patients, without signs of dental caries or periodontal disease, were submitted to extractions of teeth for orthodontic purposes, with pulpectomy performed before extraction. The pulp samples were examined with optic microscope. The detection and assessment of IL-6 were performed using immunohistochemical technique. Data were statistically analysed using non-parametric tests. According to morphopathological criteria, 42.85% were classified as acute pulpitis and 57.14% as chronic pulpitis. The pulp samples in control group were not associated with IL-6 positive cells. The analysis of all samples with acute and chronic pulpitis identified 73.80% samples with IL-6 and 26.20% associated with the absence of IL-6. The highest frequency of IL-6 positive cells was recorded in rich-cell zone of crown dental pulp. The systemic distribution of IL-6 positive cells was mostly diffused without well-defined orientation. IL-6 release in acute and chronic pulpitis is significantly higher comparing with healthy pulp tissue.

Antimicrobial Effect of 940 nm Diode Laser based on Photolysis of Hydrogen Peroxide in the Treatment of Periodontal Disease

2018 ◽  
Vol 69 (8) ◽  
pp. 2081-2088 ◽  
Author(s):  
Alin Alexandru Odor ◽  
Edwin Sever Bechir ◽  
Deborah Violant ◽  
Victoria Badea
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Therapy ◽  
Diode Laser ◽  
Antimicrobial Effect ◽  
The Other ◽  
Control Group ◽  
Group 4 ◽  
Periodontal Bacteria ◽  
Severe Periodontitis ◽  
Before And After

Moderate and severe periodontitis represents a challenge in the non-surgical periodontal therapy. Due to the lack of evidence regarding the antimicrobial effectiveness of 940 nm diode laser in periodontal treatment, this study aimed to evaluate the antimicrobial effect of hydrogen peroxide (H2O2) photolysis performed with 940 nm diode laser in the treatment of moderate and severe periodontitis. Twenty-five patients with 100 teeth were selected for this pilot study. The test teeth were randomly assigned to one of the four treatment groups: Group 1: scaling and root planning (SRP) (control group); and the following experimental groups: Group 2: H2O2; Group 3: 940 nm diode laser therapy; Group 4: 940 nm diode laser therapy and H2O2. Clinical examinations, like probing depth (PD), clinical attachment level (CAL) and bleeding on probing (BOP) were performed before and after the treatment. The microbiological evaluation, effectuated before and after the treatment, included nine periodontal bacteria species and investigated by means of real-time PCR assay. The clinical and bacterial differences in the tested groups, was assessed between control group and the other three experimental groups, as well as between the experimental groups. The total bacteria load was reduced for all four studied groups. Group 4 (diode laser + H2O2) showed significant bacterial reduction of the major periodontal bacteria like Pg., Tf., Td., Pi., Pm., Fn (p[0.001) than the other 3 groups (p]0.001). Also the periodontal clinical parameters, like PD, CAL and BOP showed a significant reduction after the photolysis of H2O2 with the 940 nm diode laser (p[0.001). Differences between tested groups showed a significant beneficial results in regard to Group 4.It is suggested that the photoactivation of H2O2 with the 940 nm diode laser can be used successfully in adjunctive to the non-surgical periodontal treatment as a bactericidal tool.

scholarly journals Psycho-Electrophysiological Benefits of Forest Therapies Focused on Qigong and Walking with Elderly Individuals

2021 ◽  
Vol 18 (6) ◽  
pp. 3004
Author(s):  
Jiyune Yi ◽  
Seul Gee Kim ◽  
Taegyu Khil ◽  
Minja Shin ◽  
Jin-Hee You ◽  
...  
Keyword(s):  
Urban Forest ◽  
Nervous Activity ◽  
Health Problems ◽  
The Other ◽  
Upper Body ◽  
Sympathetic Nervous Activity ◽  
Control Group ◽  
Beta Band ◽  
Elderly Individuals ◽  
Beneficial Effects

We developed two distinct forest therapy programs (FTPs) and compared their effects on dementia prevention and related health problems for older adults. One was focused on Qigong practice in the forest (QP) and the other involved active walking in the forest (WP). Both FTPs consisted of twelve 2-h sessions over six weeks and were conducted in an urban forest. We obtained data from 25, 18, and 26 participants aged 65 years or above for the QP, WP, and control groups, respectively. Neuropsychological scores via cognition (MoCA), geriatric depression (GDS) and quality of life (EQ-5D), and electrophysiological variables (electroencephalography, bioimpedance, and heart rate variability) were measured. We analyzed the intervention effects with a generalized linear model. Compared to the control group, the WP group showed benefits in terms of neurocognition (increases in the MoCA score, and alpha and beta band power values in the electroencephalogram), sympathetic nervous activity, and bioimpedance in the lower body. On the other hand, the QP group showed alleviated depression and an increased bioimpedance phase angle in the upper body. In conclusion, both active walking and Qigong in the forest were shown to have distinctive neuropsychological and electrophysiological benefits, and both had beneficial effects in terms of preventing dementia and relieving related health problems for elderly individuals.

scholarly journals Bisection of the X chromosome disrupts the initiation of chromosome silencing during meiosis in Caenorhabditis elegans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yisrael Rappaport ◽  
Hanna Achache ◽  
Roni Falk ◽  
Omer Murik ◽  
Oren Ram ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rna Polymerase Ii ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Transcription Analysis ◽  
X Chromosomes ◽  
Unique Character ◽  
Active Transcription ◽  
Heterogametic Sex

AbstractDuring meiosis, gene expression is silenced in aberrantly unsynapsed chromatin and in heterogametic sex chromosomes. Initiation of sex chromosome silencing is disrupted in meiocytes with sex chromosome-autosome translocations. To determine whether this is due to aberrant synapsis or loss of continuity of sex chromosomes, we engineered Caenorhabditis elegans nematodes with non-translocated, bisected X chromosomes. In early meiocytes of mutant males and hermaphrodites, X segments are enriched with euchromatin assembly markers and active RNA polymerase II staining, indicating active transcription. Analysis of RNA-seq data showed that genes from the X chromosome are upregulated in gonads of mutant worms. Contrary to previous models, which predicted that any unsynapsed chromatin is silenced during meiosis, our data indicate that unsynapsed X segments are transcribed. Therefore, our results suggest that sex chromosome chromatin has a unique character that facilitates its meiotic expression when its continuity is lost, regardless of whether or not it is synapsed.

scholarly journals The Diversity and Evolution of Sex Chromosomes in Frogs

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 483
Author(s):  
Wen-Juan Ma ◽  
Paris Veltsos
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Comparative Genomic ◽  
Ancestral State ◽  
Heteromorphic Sex Chromosomes ◽  
Genomic Studies ◽  
Evolutionary Trajectories ◽  
Heterogametic Sex

Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.

scholarly journals Antioxidant activity of Lactobacillus plantarum NJAU-01 in an animal model of aging

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qingfeng Ge ◽  
Bo Yang ◽  
Rui Liu ◽  
Donglei Jiang ◽  
Hai Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Capacity ◽  
Lactobacillus Plantarum ◽  
Meat Product ◽  
The Other ◽  
Oxidative Stress Marker ◽  
Control Group ◽  
Intragastric Administration ◽  
Aging Effects ◽  
Sterile Saline

Abstract Background Excessive reactive oxygen species (ROS) can cause serious damage to the human body and may cause various chronic diseases. Studies have found that lactic acid bacteria (LAB) have antioxidant and anti-aging effects, and are important resources for the development of microbial antioxidants. This paper was to explore the potential role of an antioxidant strain, Lactobacillus plantarum NJAU-01 screened from traditional dry-cured meat product Jinhua Ham in regulating D-galactose-induced subacute senescence of mice. A total of 48 specific pathogen free Kun Ming mice (SPF KM mice) were randomly allocated into 6 groups: control group with sterile saline injection, aging group with subcutaneously injection of D-galactose, treatments groups with injection of D-galactose and intragastric administration of 107, 108, and 109 CFU/mL L. plantarum NJAU-01, and positive control group with injection of D-galactose and intragastric administration of 1 mg/mL Vitamin C. Results The results showed that the treatment group of L. plantarum NJAU-01 at 109 CFU/mL showed higher total antioxidant capacity (T-AOC) and the antioxidant enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) than those of the other groups in serum, heart and liver. In contrast, the content of the oxidative stress marker malondialdehyde (MDA) showed lower levels than the other groups (P < 0.05). The antioxidant capacity was improved with the supplement of the increasing concentration of L. plantarum NJAU-01. Conclusions Thus, this study demonstrates that L. plantarum NJAU-01 can alleviate oxidative stress by increasing the activities of enzymes involved in oxidation resistance and decreasing level of lipid oxidation in mice.

scholarly journals The change of gut microbiota in MDD patients under SSRIs treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Shen ◽  
Xiao Yang ◽  
Gaofei Li ◽  
Jiayu Gao ◽  
Ying Liang
Keyword(s):  
Gut Microbiota ◽  
Maximum Dose ◽  
Antidepressant Treatment ◽  
Intestinal Flora ◽  
Alpha Diversity ◽  
The Other ◽  
Control Group ◽  
Depressed Patients ◽  
Metabolic Functions

AbstractThe alterations in the gut microbiota have been reported to be correlated with the development of depression. The purpose of this study was to investigate the changes of intestinal microbiota in depressed patients after antidepressant treatment. We recruited 30 MDD patients (MDD group) and 30 healthy controls (control group). The MDD group received individualized treatment with escitalopram at a maximum dose of 20 mg/day. After depressive symptoms improved to a HAMD scale score > 50%, a fecal sample was collected again and used as the follow-up group. The differences of gut microbiota between patients and controls, the characteristics of gut microbiota under treatment and the potential differences in metabolic functions were thus investigated. The Firmicutes/Bacteroidetes ratio was significantly different within three groups, and the ratio of follow-up group was significantly lower than those of the other two groups. Alpha diversity was significantly higher in MDD group than those of the other groups, and the alpha diversity was not significantly different between control and follow-up groups. The beta diversity of some patients resembled participants in the control group. The metabolic function of gut microbiota after treatment was still different from that of the control group. This study suggests that the intestinal flora of depressed patients has a tendency to return to normal under escitalopram treatment.

Role of pro-opiomelanocortin-derived peptides in the regulation of steroid production by human fetal adrenal cells in culture

1983 ◽  
Vol 97 (3) ◽  
pp. 357-367 ◽  
Author(s):  
Andrew Baird ◽  
K. W. Kan ◽  
Samuel Solomon
Keyword(s):  
Peptide Hormones ◽  
The Other ◽  
Dehydroepiandrosterone Sulphate ◽  
Steroid Production ◽  
Adrenal Cells ◽  
The Third ◽  
Cells In Culture

Synthetic (1–39)ACTH, (1–24)ACTH, (18–39)ACTH, α-MSH, met-enkephalin and α-, βand γ-endorphin were tested for their ability to stimulate steroidogenesis by human fetal adrenal cells in culture. Adrenal cells were incubated with peptide hormones for two periods of 24 h. On the third day of the experiment the cells were incubated with progesterone (4 μg/2 ml) for 8 h. At the doses tested only (1–39)ACTH, (1–24)ACTH and α-MSH stimulated steroidogenesis. None of the other peptides had any corticotrophic effect on the formation of cortisol, corticosterone or dehydroepiandrosterone sulphate (DHAS). At the highest doses tested, α-MSH (100 μg/2 ml) had a corticotrophic effect that was not different from that obtained with 20 ng (1–39)ACTH or (1–24)ACTH. At the lower doses (0·2–2 μg/2 ml), α-MSH stimulated the formation of DHAS (P<0·01) without stimulating the formation of cortisol.

Sign in / Sign up

Export Citation Format

Share Document