Gonad Development in the Parthenogenetic Haemaphysalis (Kaiseriana) longicornis Neumann (Ixodoidea: Ixodidae)

1972 ◽  
Vol 58 (4) ◽  
pp. 817 ◽  
Author(s):  
Galila M. Khalil
Keyword(s):  
Gonad Development

IMPLANTATION OF LHRH-a HORMONE TO STIMULATION OF GONAD DEVELOPMENT OF HUMPBACK GROUPER SECOND GENERATION ( F-2 )

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Tridjoko Tridjoko
Keyword(s):  
Body Weight ◽  
Second Generation ◽  
Gonad Development ◽  
Gonadal Development ◽  
Oocyte Diameter ◽  
2Nd Generation ◽  
Length Range ◽  
Concrete Tank ◽  
Implant Treatment ◽  
Stimulation Of

This study aimed to determine the effect of LHRH-a hormone implantation on gonadal development of humpback grouper, Cromileptes altivelis 2nd generation (F-2). Individuals used were 20 female grouper fish with weight range of 600-800 gram/fish and total length range of 28.0-30.0 cm. The treatment used 5 fish each with tagging. Grouper fishes were stocked into the 75 m3 circular concrete tank. Hormone of LHRH-a with dosage of 50 μg/kg body weight was used as implant treatment of (A) 1 time,, (B) 2 times, (C) 3 times, and (D) without implant. The results showed that implantation of LHRH-a hormone were significantly stimulate gonad development of humpback grouper second generation (F-2). Treatment of 3 times implant every month showed the best results produced  oocyte diameter up to 480 μm, while the control of oocyte diameter only reached <400 μm. Keywords: LHRH-a hormone, implantation, Humpback grouper, gonad development

scholarly journals Facultative and obligate diapause phenotypes in populations of the European spruce bark beetle Ips typographus

2021 ◽  
Author(s):  
Martin Schebeck ◽  
Nina Dobart ◽  
Gregory J. Ragland ◽  
Axel Schopf ◽  
Christian Stauffer
Keyword(s):  
Bark Beetle ◽  
Ovarian Development ◽  
Insect Pest ◽  
Gonad Development ◽  
Ips Typographus ◽  
Life Cycles ◽  
Species Variation ◽  
Northern European ◽  
Spruce Bark ◽  
Egg Number

AbstractThe bark beetle Ips typographus is the most destructive insect pest in Norway spruce-dominated forests. Its potential to establish multiple generations per year (multivoltinism) is one major trait that makes this beetle a severe pest. Ips typographus enters diapause to adjust its life cycle to seasonally changing environments. Diapause is characterized by developmental and reproductive arrest; it prolongs generation time and thus affects voltinism. In I. typographus a facultative, photoperiod-regulated diapause in the adult stage has been described. In addition, the presence of an obligate, photoperiod-independent, diapause has been hypothesized. The diapause phenotype has important implications for I. typographus voltinism, as populations with obligate diapausing individuals would be univoltine. To test for the presence of different I. typographus diapause phenotypes, we exposed Central and Northern European individuals to a set of photoperiodic treatments. We used two ovarian traits (egg number and vitellarium size) that are associated with gonad development, to infer reproductive arrest and thus diapause. We found a distinct effect of photoperiod on ovarian development, with variable responses in Central and Northern European beetles. We observed obligate diapausing (independent of photoperiod) individuals in Northern Europe, and both facultative (photoperiod-regulated) as well as obligate diapausing individuals in Central Europe. Our results show within-species variation for diapause induction, an adaptation to match life cycles with seasonally fluctuating environmental conditions. As the diapause phenotype affects the potential number of generations per season, our data are the basis for assessing the risk of outbreaks of this destructive bark beetle.

scholarly journals lin-35/Rb and xnp-1/ATR-X function redundantly to control somatic gonad development in C. elegans

2004 ◽  
Vol 273 (2) ◽  
pp. 335-349 ◽  
Author(s):  
Aaron M. Bender ◽  
Orion Wells ◽  
David S. Fay
Keyword(s):  
Gonad Development ◽  
C Elegans ◽  
Somatic Gonad

Gonad morphology and gametogenesis in the deep-sea jellyfish Atolla wyvillei and Periphylla periphylla (Scyphozoa: Coronatae) collected from Cape Hatteras and the Gulf of Mexico

2009 ◽  
Vol 90 (6) ◽  
pp. 1095-1104 ◽  
Author(s):  
Cathy H. Lucas ◽  
Adam J. Reed
Keyword(s):  
Gulf Of Mexico ◽  
Gonad Development ◽  
Bell Diameter ◽  
Western Atlantic ◽  
Gonad Morphology ◽  
Time Period ◽  
Cape Hatteras ◽  
Literature Evidence ◽  
Long Time ◽  
North Western

Observations on gonad morphology and the structure of ovaries and testes of the coronate scyphozoans Atolla wyvillei and Periphylla periphylla are described based on samples collected from the Gulf of Mexico and Cape Hatteras (north-western Atlantic). In A. wyvillei, gonads of distinguishable sex were observed in medusae as small as 17 mm bell diameter (BD). Spermatogenesis occurred within follicles (average 366 × 254 μm) that were evenly distributed throughout the gonad. Oocytes in different stages of development were observed in all the females with gonads. Oocytes arise from the gastrodermis and migrate into the mesoglea to develop from early-mid to late vitellogenic oocytes characterized by a large nucleus and granular (organic-rich) cytoplasm. The largest oocytes measured were 543 μm and 263 μm from the Gulf of Mexico and Cape Hatteras respectively. Possible reasons for this difference are discussed. In P. periphylla gonads were also initially observed in medusae 17 mm BD, although not all larger medusae had obvious gonads. Unlike A. wyvillei sperm follicles were arranged in long convoluted rows normally only one follicle thick. The organization of ooytes in female P. periphylla was very similar to A. wyvillei, although the gonads were small and the number of oocytes present in each gonad very low (<22). The largest oocyte measured was 777 μm in a 53 mm BD medusa. Although medusae were collected from one time period only (September) in this study, our findings appear to be in agreement with literature evidence indicating that coronate jellyfish produce few eggs continuously over a long time period. Aspects of gonad development and gametogenesis are discussed with respect to potential differences in site productivity and species identification.

scholarly journals Effects of endocrine disrupting chemicals on gonad development: Mechanistic insights from fish and mammals

2021 ◽  
pp. 112040
Author(s):  
G. Delbes ◽  
M. Blázquez ◽  
J.I. Fernandino ◽  
P. Grigorova ◽  
B.F. Hales ◽  
...  
Keyword(s):  
Endocrine Disrupting Chemicals ◽  
Gonad Development ◽  
Endocrine Disrupting

scholarly journals A Critical Point of Male Gonad Development: Neuroendocrine Correlates of Accelerated Testicular Growth in Rats during Early Life

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e93007 ◽  
Author(s):  
Nikolay N. Dygalo ◽  
Tatjana V. Shemenkova ◽  
Tatjana S. Kalinina ◽  
Galina T. Shishkina
Keyword(s):  
Critical Point ◽  
Early Life ◽  
Gonad Development ◽  
Male Gonad ◽  
Testicular Growth

Transcriptional inhibition of steroidogenic factor 1 in vivo in Oreochromis niloticus increased weight and suppressed gonad development

Gene ◽  
2021 ◽  
pp. 146023
Author(s):  
Zhe-Ming Cao ◽  
Jun Qiang ◽  
Jun-Hao Zhu ◽  
Hong-Xia Li ◽  
Yi-Fan Tao ◽  
...  
Keyword(s):  
Oreochromis Niloticus ◽  
Gonad Development ◽  
Steroidogenic Factor 1 ◽  
Transcriptional Inhibition

Characterization and expression pattern of zebrafish anti-Müllerian hormone (amh) relative to sox9a, sox9b, and cyp19a1a, during gonad development

2005 ◽  
Vol 5 (5) ◽  
pp. 655-667 ◽  
Author(s):  
Adriana Rodríguez-Marí ◽  
Yi-Lin Yan ◽  
Ruth A. BreMiller ◽  
Catherine Wilson ◽  
Cristian Cañestro ◽  
...  
Keyword(s):  
Expression Pattern ◽  
Gonad Development
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