Comparative morphology of the gonadal structure related to reproductive strategies in six species of neotropical catfishes (Teleostei: Siluriformes)

2011 ◽  
Vol 272 (5) ◽  
pp. 525-535 ◽  
Author(s):  
Rafael Magno Costa Melo ◽  
Fábio Pereira Arantes ◽  
Yoshimi Sato ◽  
José Enemir dos Santos ◽  
Elizete Rizzo ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Comparative Morphology ◽  
Gonadal Structure

Review: Sperm: Comparative morphology and function related to altered reproductive strategies and fertility in mammals

2018 ◽  
Vol 34 (6) ◽  
pp. 558-565
Author(s):  
Shannon Kate Thompson ◽  
Naseer A. Kutchy ◽  
Samantha Kwok ◽  
Zulfi N.A. Rosyada ◽  
Ikhide G. Imumorin ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Comparative Morphology ◽  
And Function

Comparative Morphology of Intercellular Bridges Between Developing Germ Cells of the Ovary

1970 ◽  
Vol 28 ◽  
pp. 328-329
Author(s):  
J. R. Ruby ◽  
R. F. Dyer ◽  
R. G. Skalko ◽  
R. F. Gasser ◽  
E. P. Volpe
Keyword(s):  
Germ Cells ◽  
Rana Pipiens ◽  
Comparative Morphology ◽  
Dense Material ◽  
Individual Species ◽  
Microscope Examination ◽  
Electron Dense Material ◽  
Intercellular Bridges ◽  
Cytoplasmic Side ◽  
Intercellular Connections

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.

Comparative morphology of Pneumocystis Carinii in Situ and after bronchoalveolar lavage

1986 ◽  
Vol 44 ◽  
pp. 244-245
Author(s):  
C. A. Itatani ◽  
A. Hing ◽  
W. Jackson ◽  
G.J. Marshall
Keyword(s):  
Bronchoalveolar Lavage ◽  
Pneumocystis Carinii ◽  
Comparative Morphology

Pneumocystis carinii (PC) is an organism capable of causing fatal pneumonia in immune suppressed individuals and has recently gained prominence because of its association with AIDS. A similar organism occurs in rats and infection may be induced with cortisone injections. In order to isolate PC for further study bronchoal veol ar lavage (BAL) was performed. Differences in the ul trastructure of BAL-obtained organisms and PC in situ were observed and are herein reported.

Neonatal nutritional strategy of a viviparous elasmobranch with extremely low reproductive output

2020 ◽  
Vol 638 ◽  
pp. 107-121 ◽  
Author(s):  
BS Rangel ◽  
NE Hussey ◽  
Y Niella ◽  
LA Martinelli ◽  
AD Gomes ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Reproductive Strategies ◽  
Trophic Ecology ◽  
Essential Fatty Acids ◽  
Physiological State ◽  
Maternal Investment ◽  
Early Life History ◽  
Nutritional State ◽  
Disc Width ◽  
Biomarker Analysis

Throughout evolutionary history, elasmobranchs have developed diverse reproductive strategies. Little focused work, however, has addressed how neonatal nutritional state is affected by differing degrees of maternal investment associated with these markedly different reproductive strategies. To investigate the effect of maternal investment on the nutritional quality of pups during the early life history of an extremely viviparous elasmobranch, quantitative biomarker analysis including lipids, fatty acids and stable isotopes was conducted. Using the cownose ray Rhinoptera bonasus (histotrophic viviparous) as a model, we found that pups were initially born in a positive nutritional state, enriched in physiologically important essential fatty acids and nitrogen and carbon stable isotope values (δ15N and δ13C), a result of maternal intrauterine transfer. A systematic decrease in some fatty acids and δ15N values, as well as a decrease in cholesterol with growth, confirmed that these substrates were derived from maternal resources and used in initial metabolic processes following birth. An observed increase in condition factor, plasma essential fatty acids and triglyceride:cholesterol ratio with increasing body size identified a progression towards successful independent foraging with pups not displaying marked nutritional deficiency or fasting phases. Our multi-tracer approach allowed the identification of 2 size classes of young rays (<50 and <70 cm disc width) that displayed distinct physiological states. Since prenatal maternal investment is critical for offspring condition and to promote successful foraging post birth, understanding the trophic ecology and physiological state of pups during their first year is critical to guide management and conservation within nursery grounds.

Comparative Morphology of Skeletal Muscles in Man and Macaque

1993 ◽  
Vol 5 (2) ◽  
pp. 137-146
Author(s):  
Seiichiro INOKUCHI ◽  
Tadanao KIMURA ◽  
Masataka SUZUKI ◽  
Junji ITO ◽  
Hiroo KUMAKURA
Keyword(s):  
Skeletal Muscles ◽  
Comparative Morphology
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