نتایج جستجو برای: gonad morphology

تعداد نتایج: 149572  

2017
Dena M Leerberg Kaori Sano Bruce W Draper

The vertebrate ovary and testis develop from a sexually indifferent gonad. During early development of the organism, primordial germ cells (the gamete lineage) and somatic gonad cells coalesce and begin to undergo growth and morphogenesis to form this bipotential gonad. Although this aspect of development is requisite for a fertile adult, little is known about the genetic regulation of early go...

Journal: :Mechanisms of Development 2000
Karin Wertz Bernhard G Herrmann

The vertebrate gonad develops from the intermediate mesoderm as an initially bipotential organ anlage, the genital ridge. In mammals, Sry acts as a genetic switch towards testis development. Sox9 has been shown to act downstream of Sry in testis development, while Dax1 appears to counteract Sry. Few more genes have been implicated in early gonad development. However, the genetic networks contro...

ژورنال: بوم شناسی آبزیان 2015
Mohammadizadeh, Felora , Rezvani, Fatemeh , Salarzadeh, Ali Reza ,

Sea cucumber species are commercially important in the world. This study explored the reproductive biology of sand fish sea Cucumber in Qeshmisalnd in the Persain Gulf for a year, from December 2012 to November 2013. The macroscopic study intended to examine the features such as gonad color, gonad weight, their length and diameter, and specify the spawning season. Microscopic examinations inclu...

2012
Marij J. Frantzen Simon Robben Alida A. Postma Johannes Zoetelief Joachim E. Wildberger Gerrit J. Kemerink

OBJECTIVE To re-evaluate gonad shielding in paediatric pelvic radiography in terms of attainable radiation risk reduction and associated loss of diagnostic information. METHODS A study on patient dose and the quality of gonad shielding was performed retrospectively using 500 pelvic radiographs of children from 0 to 15 years old. In a subsequent study, 195 radiographs without gonad shielding w...

Journal: :Nature 1973

Journal: :Reproduction, nutrition, development 2006
Katarzyna Dziewulska Józef Domagała

The study was aimed at analysing body size in relation to form of gonad maturation (amount of mature germ cells) in 329 under-yearling sea trout males. The fish, aged 7 months, were caught in late October-early November in 3 streams located in north-western Poland. Each stream supported fish belonging to a different sib group. Standard histological techniques and a computer image analysis progr...

Journal: :Development 2006
Wendy R Mathews Daniel Ong Allison B Milutinovich Mark Van Doren

Embryonic gonad formation involves intimate contact between germ cells and specialized somatic cells along with the complex morphogenetic movements necessary to create proper gonad architecture. Previously, we have shown that gonad formation in Drosophila requires the homophilic cell-adhesion molecule Drosophila E-cadherin (DE-cadherin), and also Fear of Intimacy (FOI), which is required for st...

Background: Gonad shielding has been recommended during pelvic x-rays since the 1950s. The popular method of gonad shielding is placement a lead shield in the midline of the pelvis. The aim of this study was to evaluate the prevalence and utility of gonad shielding in pediatrics undergoing pelvic x-rays.Materials and MethodsFollowing study approval, we retrospectively retrieved data from the di...

Journal: :Development 1995
M Boyle S DiNardo

The adult ovaries and testes contain several specialized somatic cell types that support the differentiation of germ cells into mature gametes. Each of these cell types arise from mesodermal cells that constitute the embryonic gonad. To explore the mechanisms governing the development and differentiation of these cells, we focus on the formation of the gonad during Drosophila development. Using...

2015
Mary B. Kroetz David Zarkower

The Caenorhabditis elegans somatic gonad differs greatly between the two sexes in its pattern of cell divisions, migration, and differentiation. Despite decades of study, the genetic pathways directing early gonadal development and establishing sexual dimorphism in the gonad remain largely unknown. To help define the genetic networks that regulate gonadal development, we employed cell-specific ...

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