Changes in Proximate Composition of the Crayfish Orconectes propinquus with Size, Sex, and Life Stage

1976 ◽  
Vol 33 (11) ◽  
pp. 2450-2458 ◽  
Author(s):  
Roy A. Stein ◽  
Michael L. Murphy
Keyword(s):  
Proximate Composition ◽  
Carapace Length ◽  
Inorganic Material ◽  
Life Stage ◽  
Dry Weight ◽  
Adult Males ◽  
Mineral Salts ◽  
Orconectes Propinquus ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics

We estimated percent water, inorganic material, and chitin for the crayfish Orconectes propinquus. To properly account for organic materials and mineral salts, we burned samples first at 550 C then at 650 C for estimates of the inorganic fraction. More precise estimates were obtained at 650 C; thus, to account for the conversion of CaCO3 to CaO and CO2 at 650 C, inorganic estimates were multiplied by an empirically derived factor (1.5) to convert all values to total inorganic material. For chitin, acid decalcification, followed by deproteinization with base and combustion at 650 C, provided best estimates. Proximate composition varied with size, sex, and molt stage. Percent water was inversely related to size for juveniles but was constant with size in adult males (68.4%) and females (67.4%). Percent inorganic material and chitin of dry weight increased with size in juveniles; inorganic continued to increase with size following maturity while percent chitin remained constant. For a carapace length of 25 mm, adult males had significantly more inorganic material (46.2 vs. 38.1%) and chitin (16.3 vs. 14.1%) than adult females. Differences in proximate composition appeared related to secondary sexual characteristics, with males having longer, wider chelae but narrower abdomens than females. Recent molts had more water (84.1%) and less inorganic (19.0%) and chitin (9.1%) than either male or female intermolts. Understanding how these proximates vary with life stage is necessary for adequately describing transfer of energy and biomass between populations.

Masculinized females in a population of Leptodiaptomus minutus (Copepoda, Calanoida)

1998 ◽  
Vol 76 (3) ◽  
pp. 596-600 ◽  
Author(s):  
Kristine B Sillett ◽  
Richard S Stemberger
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Adult Males ◽  
Secondary Sexual Characteristics ◽  
Adult Females ◽  
Internal Morphology ◽  
Sexual Characteristics ◽  
The Common ◽  
Normal Males ◽  
Normal Adults

In a population of the common freshwater copepod Leptodiaptomus minutus Lilljeborg, 7.3% of adult females exhibited male secondary sexual characteristics. Although these masculinized or intersex females had the internal morphology of normal females, they possessed one or rarely two normal geniculate male antennules, and in a few instances male fifth legs. The sex ratio of normal adult males to females in the population was 1:1. No differences in body size among normal males, normal females, and masculinized females were found. Antennule lengths of males and masculinized females were not significantly different from one another; however, normal females had longer antennules than either males or masculinized females. Mating experiments indicated that masculinized females were functionally female and they were able to mate with normal males to produce offspring that were normal or masculinized. The occurrence of intersex copepods in lakes of North America may be more widespread than we now recognize because they can be easily overlooked or mistaken for normal adults.

Association of Life Stage Lead Exposures with Pubertal Onset and Hormones Related to Secondary Sexual Characteristics in a Mexican Birth Cohort

2014 ◽  
Vol 2014 (1) ◽  
pp. 2713
Author(s):  
Karen E. Peterson* ◽  
Deborah J. Watkins ◽  
Myriam Afeiche ◽  
Zhenzhen Zhang ◽  
David Cantonwine ◽  
...  
Keyword(s):  
Birth Cohort ◽  
Life Stage ◽  
Pubertal Onset ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Secondary Sexual

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

Reproductive failure of the red shiner (Cyprinella lutrensis) after exposure to an exogenous estrogen

2010 ◽  
Vol 67 (11) ◽  
pp. 1730-1743 ◽  
Author(s):  
Michelle M. McGree ◽  
Dana L. Winkelman ◽  
Nicole  K.M.  Vieira ◽  
Alan  M.  Vajda
Keyword(s):  
Reproductive Success ◽  
Great Plains ◽  
Endocrine Disrupting Chemicals ◽  
Water Control ◽  
Secondary Sexual Characteristics ◽  
Cyprinella Lutrensis ◽  
The Us ◽  
Sexual Characteristics ◽  
Solvent Control ◽  
17Β Estradiol

Endocrine disrupting chemicals (EDCs) have been detected in surface waters worldwide and can lead to developmental and reproductive disruption in exposed fishes. In the US Great Plains, EDCs are impacting streams and rivers and may be causing adverse reproductive effects. To examine how estrogenic EDCs might affect reproductive success of plains fishes, we experimentally exposed male red shiners ( Cyprinella lutrensis ) to exogenous 17β-estradiol. We characterized the effects of estradiol on male gonadal histology and secondary sexual characteristics, determined whether exposure reduced reproductive success, and examined the effects of depuration. Adults were exposed to a mean concentration of 70 ng·L−1 estradiol, a solvent control, or a water control for at least 83 days. Male exposure to estradiol resulted in elevated plasma vitellogenin concentrations, changes in spermatogenesis, reduced mating coloration and tubercles, altered mating behaviors, and reduced reproductive success with no viable progeny produced. Reproductive endpoints improved upon depuration (28 days). Exposure to estradiol had significant adverse effects on red shiners, indicating that wild populations may face developmental and reproductive difficulties if they are chronically exposed to estradiol.

Comparative urogenital morphology and external sex determination in muskellunge, Esox masquinongy Mitchill

1989 ◽  
Vol 67 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Bernard Lebeau ◽  
Gérard Pageau
Keyword(s):  
Ventral Surface ◽  
Northern Pike ◽  
Structural Basis ◽  
Simple Method ◽  
Esox Masquinongy ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Spawning Behaviour ◽  
Accurate Indicator ◽  
Secondary Sexual

Primary and secondary sexual characteristics in northern pike, Esox lucius Linneaus, and muskellunge, Esox masquinongy Mitchill, differ markedly. Differences in the internal urogenital anatomy include the structure of the genital ducts and the angle they form with the ventral surface. Externally, the genital and urinary ducts open directly to the environment in northern pike, whereas in muskellunge they open into a muscular papilla and then through a urogenital pore. Differences in sexual dimorphism between the two closely related esocids constitute a structural basis to explain the known differences in spawning behaviour and reproductive success. Differences in secondary sexual characteristics explain why the methods developed by Demchenko or Casselman to externally sex pike are inapplicable to muskellunge. To develop and test two external sexing techniques for muskellunge, specimens were collected from two regions in Canada from 1980 to 1987. Examination of reproductive products obtained from stripping provided an accurate indicator of sex and sexual maturity, but demonstrated serious limitations. A simple method to sex muskellunge by examination of the external urogenital morphology is described for juveniles and adults. Dissection of fish revealed that with the urogenital examination technique we sexed juveniles with a success rate of 92–98%, and adults with 100% accuracy.

REPLACEMENT ORAL ETHINYLOESTRADIOL THERAPY FOR GONADAL DYSGENESIS: GROWTH AND ADRENAL ANDROGEN STUDIES

1979 ◽  
Vol 91 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Anne W. Lucky ◽  
Samuel P. Marynick ◽  
Robert W. Rebar ◽  
Gordon B. Cutler ◽  
Michael Glen ◽  
...  
Keyword(s):  
Gonadal Dysgenesis ◽  
Bone Age ◽  
Pubic Hair ◽  
Height Velocity ◽  
First Year ◽  
Adrenal Androgen ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Second Year ◽  
Pre Treatment

ABSTRACT We have studied growth and adrenal dehydroepiandrosterone (DHA) responses to iv synthetic adrenocorticotrophic hormone (ACTH, Cortrosyn) in 6 girls with gonadal dysgenesis before and during treatment with lowdose ethinyloestradiol (EOe2). In all patients there was a statisfactory induction of secondary sexual characteristics including increase in breasts and pubic hair and onset of withdrawal bleeding within 6 months of therapy. Height velocity increased from 2.8 ± 0.9 cm/year pre-treatment to 5.3 ± 1.5 cm/year (P < 0.02) in the first year. There was deceleration to 1.9 ± 1.1 cm/year in the second year. There was no disproportionate advancement in bone age and thus, presumably, no loss of ultimate height. We could demonstrate no change in basal or ACTH-stimulated levels of DHA, a specific adrenal androgen, to account for the increased pubic hair and growth in these patients.

The effects of phthalate and nonylphenol exposure on body size and secondary sexual characteristics during puberty

2015 ◽  
Vol 218 (7) ◽  
pp. 603-615 ◽  
Author(s):  
Jia-Woei Hou ◽  
Ching-Ling Lin ◽  
Yen-An Tsai ◽  
Chia-Huang Chang ◽  
Kai-Wei Liao ◽  
...  
Keyword(s):  
Body Size ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Secondary Sexual

scholarly journals Somatotypical features of the age dynamics of secondary sexual characteristics and functional parameters in city schoolchildren

2021 ◽  
pp. 113-118
Author(s):  
V. A. Melnik
Keyword(s):  
Blood Pressure ◽  
Body Type ◽  
Age Dynamics ◽  
Functional Parameters ◽  
Secondary Sexual Characteristics ◽  
Age Related ◽  
Sexual Characteristics ◽  
Age Range ◽  
Age Related Changes ◽  
Secondary Sexual

Objective: to assess the constitutional features of the age dynamics of secondary sexual characteristics and functional parameters of city schoolchildren in the age range of 7–17 years.Materials and methods. The objects of the study were schoolchildren aged 7–17. The stages of the expression of secondary sexual characteristics were determined visually according to the scheme by J.M. Tanner. The functional parameters of the examined schoolchildren were assessed using the methods of dynamometry, spirometry; blood pressure and heart rates, as well as the time of simple sensorimotor reactions were measured.Results. As a result of the performed studies, it has been found that representatives of the hypersomnic types are ahead of other types to reveal the first stages of secondary sexual characteristics. Schoolchildren with the leptosomic morphotypes due to higher rates of their development have reached the definitive stages by the same age as those with the hypersomnic variants. The intensity of age-related changes in functional parameters (strength qualities, circulatory and respiratory systems, nervous system) in the studied objects depends on their body type.Conclusion. The stage and rate of puberty, as well as the development of functional parameters in city schoolchildren depends on their somatotype.

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