Time required for sex change in teleost fishes: Hormonal dynamics shaped by selection

2016 ◽  
Vol 407 ◽  
pp. 339-348 ◽  
Author(s):  
Sachi Yamaguchi
Keyword(s):  
Sex Change ◽  
Teleost Fishes ◽  
Time Required

scholarly journals Idea Paper: Effects of gonad type and body mass on the time required for sex change in fishes

2021 ◽  
Author(s):  
Soma Tokunaga ◽  
Tatsuru Kadota ◽  
Yuuki Y. Watanabe ◽  
Tetsuo Kuwamura ◽  
Yuuki Kawabata
Keyword(s):  
Sex Change ◽  
High Temporal Resolution ◽  
Scaling Exponent ◽  
Large Species ◽  
Teleost Fishes ◽  
Metabolic Scaling ◽  
Factors Influencing ◽  
Opposite Sex ◽  
Time Required ◽  
Male To Female

AbstractSex change is a well-known phenomenon in teleost fishes, and it takes several days to a few months depending on the species and direction of sex change. However, the underlying factors influencing the time required for sex change (TS) remain unclear. Given that the time for producing a new gonad largely determines TS, the gonad type (i.e., whether fish retain the gonad of opposite sex or not [delimited or non-delimited]) and metabolic rate are the ultimate determinants of TS. This study sought to test two hypotheses: (1) the delimited gonad shortens TS; and (2) TS scales with mass0.1–0.2, because the metabolic scaling exponent (β) in fishes is 0.8–0.9 and biological times scale with mass1−β in general. We compiled data on TS for 12 female-to-male and 14 male-to-female sex-changing species from the literature. Results of individual examinations of the effects of gonad type and mass were consistent with our hypotheses. However, upon simultaneous examination of the effects of gonad type and mass, these effects became unclear because of their strong multicollinearity. The compiled data for delimited and non-delimited gonads were biased toward the smaller and larger species, respectively, precluding us from being able to statistically distinguish between these effects. Small species with non-delimited gonads and large species with delimited gonads exist; however, their TS has not been measured with high temporal resolution thus far. Therefore, additional experiments on these species are required to statistically distinguish between, as well as to better understand, the effects of gonad type and mass on TS.

scholarly journals Testicular inducing steroidogenic cells trigger sex change in groupers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryosuke Murata ◽  
Ryo Nozu ◽  
Yuji Mushirobira ◽  
Takafumi Amagai ◽  
Jun Fushimi ◽  
...  
Keyword(s):  
Teleost Fish ◽  
Sex Change ◽  
Teleost Fishes ◽  
Evolution Of Sex ◽  
Ecological Studies ◽  
Sequential Hermaphroditism ◽  
Protogynous Hermaphrodite ◽  
Male Sex ◽  
Steroidogenic Cells

AbstractVertebrates usually exhibit gonochorism, whereby their sex is fixed throughout their lifetime. However, approximately 500 species (~ 2%) of extant teleost fishes change sex during their lifetime. Although phylogenetic and evolutionary ecological studies have recently revealed that the extant sequential hermaphroditism in teleost fish is derived from gonochorism, the evolution of this transsexual ability remains unclear. We revealed in a previous study that the tunica of the ovaries of several protogynous hermaphrodite groupers contain functional androgen-producing cells, which were previously unknown structures in the ovaries of gonochoristic fishes. Additionally, we demonstrated that these androgen-producing cells play critical roles in initiating female-to-male sex change in several grouper species. In the present study, we widened the investigation to include 7 genera and 18 species of groupers and revealed that representatives from most major clades of extant groupers commonly contain these androgen-producing cells, termed testicular-inducing steroidogenic (TIS) cells. Our findings suggest that groupers acquired TIS cells in the tunica of the gonads for successful sex change during their evolution. Thus, TIS cells trigger the evolution of sex change in groupers.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Search mode for rapid detection of virus particles

1991 ◽  
Vol 49 ◽  
pp. 286-287
Author(s):  
O. E. Bradfute
Keyword(s):  
Electron Microscopy ◽  
Rapid Detection ◽  
Plant Virus ◽  
Low Dose ◽  
Search Mode ◽  
Virus Diseases ◽  
Virus Particles ◽  
Focus Image ◽  
Time Required ◽  
Rapid Switching

Electron microscopy is frequently used in preliminary diagnosis of plant virus diseases by surveying negatively stained preparations of crude extracts of leaf samples. A major limitation of this method is the time required to survey grids when the concentration of virus particles (VPs) is low. A rapid survey of grids for VPs is reported here; the method employs a low magnification, out-of-focus Search Mode similar to that used for low dose electron microscopy of radiation sensitive specimens. A higher magnification, in-focus Confirm Mode is used to photograph or confirm the detection of VPs. Setting up the Search Mode by obtaining an out-of-focus image of the specimen in diffraction (K. H. Downing and W. Chiu, private communications) and pre-aligning the image in Search Mode with the image in Confirm Mode facilitates rapid switching between Modes.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Clinical Update: Functional Capacity Evaluations—An Update

1999 ◽  
Vol 4 (5) ◽  
pp. 4-7 ◽  
Author(s):  
Laura Welch
Keyword(s):  
Job Performance ◽  
Functional Capacity ◽  
Injury Risk ◽  
Disability Evaluation ◽  
Time Period ◽  
Submaximal Effort ◽  
Lack Of Sleep ◽  
Overall Performance ◽  
Time Required ◽  
Specific Limitation

Abstract Functional capacity evaluations (FCEs) have become an important component of disability evaluation during the past 10 years to assess an individual's ability to perform the essential or specific functions of a job, both preplacement and during rehabilitation. Evaluating both job performance and physical ability is a complex assessment, and some practitioners are not yet certain that an FCE can achieve these goals. An FCE is useful only if it predicts job performance, and factors that should be assessed include overall performance; consistency of performance across similar areas of the FCE; consistency between observed behaviors during the FCE and limitations or abilities reported by the worker; objective changes (eg, blood pressure and pulse) that are appropriate relative to performance; external factors (illness, lack of sleep, or medication); and a coefficient of variation that can be measured and assessed. FCEs can identify specific movement patterns or weaknesses; measure improvement during rehabilitation; identify a specific limitation that is amenable to accommodation; and identify a worker who appears to be providing a submaximal effort. FCEs are less reliable at predicting injury risk; they cannot tell us much about endurance over a time period longer than the time required for the FCE; and the FCE may measure simple muscular functions when the job requires more complex ones.

Characterization and evolution of spearfishing in Madeira archipelago, Eastern Atlantic

2020 ◽  
Vol 33 ◽  
pp. 15
Author(s):  
Roi Martínez-Escauriaza ◽  
Claudio Vieira ◽  
Lídia Gouveia ◽  
Nuno Gouveia ◽  
Margarida Hermida
Keyword(s):  
Fish Species ◽  
Young Men ◽  
Coastal Areas ◽  
Teleost Fishes ◽  
The North ◽  
Southeast Coast ◽  
Madeira Archipelago ◽  
First Time

Data obtained from licenses of spearfishers and surveys conducted in 2004 and 2017 allowed for the analysis, for the first time, of the practice of spearfishing in the Madeira archipelago. Only a small percentage of the population practices spearfishing, mostly local young men. Most of them practice the activity with a partner throughout most of the year and along most of the island's coastal areas, although preferentially along the North and Southeast coast. Results show how, in recent years, despite the population of spearfishers decreasing, the abundance in the annual catch potentially increased, probably due to the higher investment of time in this activity. It has been observed that many fishers complement their catches with manual collecting of invertebrates. Overall, 40 teleost fishes and also 4 crustaceans and 8 molluscs were identified. The most frequently captured fish species were parrotfish and white seabream, while limpets were the most collected invertebrates in both selected periods.

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