Spermatogenesis and sperm morphology in Trophon geversianus (Gastropoda: Muricidae)

2013 ◽  
Vol 93 (7) ◽  
pp. 1881-1886 ◽  
Author(s):  
Juliana Giménez
Keyword(s):  
Sperm Morphology ◽  
Developmental Pattern ◽  
Diagnostic Feature ◽  
Tail Region ◽  
Acrosomal Vesicle ◽  
Dense Nucleus ◽  
Dense Vesicles

The ultrastructure of spermatogenesis, the euspermatozoa and paraspermatozoa, is investigated in Trophon geversianus. Spermatogenesis follows the general developmental pattern of caenogastropods. Paraspermatid development is characterized by elongation of the cell, concurrent with the appearance of a cytoplasmic elongation at the apex of the cell and the breakdown of the nucleus into small round fragments (caryomerites). Euspermatozoa consist of: a tall, conical acrosomal vesicle (with a invagination); a rod-shaped, highly electron-dense nucleus with an internal axoneme; an elongate midpiece consisting of the axoneme sheathed by helical mitochondrial elements; an elongate glycogen piece; and a short free-tail region. Paraspermatozoa of T. geversianus are vermiform. They contain approximately 12–16 axonemes arranged peripherally, numerous oblong dense vesicles, numerous less dense (round) vesicles, and scattered mitochondria. Most of the euspermatozoal features of T. geversianus are also observed in many neogastropods. However, the presence of the axoneme continuously located inside of the nucleus has not been reported before, and may prove to be a diagnostic feature of the Muricidae.

Sperm morphology of two species of Olivancillaria (Gastropoda: Olividae) from the south-western Atlantic

2012 ◽  
Vol 93 (3) ◽  
pp. 825-831 ◽  
Author(s):  
Valeria Teso ◽  
Juliana Giménez
Keyword(s):  
Sperm Morphology ◽  
Sperm Ultrastructure ◽  
Tail Region ◽  
Western Atlantic ◽  
Acrosomal Vesicle ◽  
Double Electron ◽  
Snail Family ◽  
Membrane Bound ◽  
Slight Narrowing ◽  
Different Levels

Sperm ultrastructure in two species of the marine snail family Olividae is examined. Euspermatozoa of both species are composed of a conical, membrane-bound acrosomal vesicle; an axial rod and a basal plate similar in both species; a solid and highly electron-dense nucleus; an elongate midpiece consisting of the axoneme sheathed by helical mitochondrial elements; an elongate glycogen piece; a double electron-dense ring at the junction of the midpiece and glycogen piece; and a free tail region. The slight narrowing in the acrosomal vesicle invagination is situated in different levels between Olivancillaria deshayesiana and Olivancillaria carcellesi. This morphology could be considered as a specific character. The length of the nucleus in O. carcellesi and in O. deshayesiana is shorter than that of other neogastropods, and could be diagnostic at family level.

scholarly journals Effect of Men Infertility on Serum Creatine ‎Kinase Activity ‎

2017 ◽  
Vol 26 (2) ◽  
pp. 141-149
Author(s):  
Safa Wahab Azize ◽  
Nadia Hasan Kadhim
Keyword(s):  
Sperm Morphology ◽  
Creatine Kinase Activity ◽  
Semen Parameters ◽  
Control Group ◽  
Diagnostic Feature ◽  
Male Factor ◽  
Infertile Men ◽  
Abnormal Sperm ◽  
Infertile Patients ◽  
Important Diagnostic Feature

mThe present study was carried out on 60 patientsm with male factor infertility comparedmwith 60 healthy controls, their ages ranged betweenn20-56 years in Maternity and Childhood Teaching Hilla Hospital and in a biochemistry laboratory of Pharmacy college of Babylon university,  between Junem2014 – Junuary 2015. The purpose of this study is to investigate CK activity, serum creatine,mcreatinine levels and semen parametersmin infertile men only ,infertile with DM, smoking ifertile,nand hypertention with infertile patients. The present resultsbshowed a statistically significant deferences (p<0.05) in creatine kinasehactivity, creatine and seminal characteristics while nonmsignificant in creatinine and in Abnormal sperm morphology % . There were statistically significant deferences betweenkthe biochemical and seminal parameters inodiabetes , hypertension and smoking patients and tomcontrol group at a p valuem(P<0.05). There were no observed significantkdifferences in creatinine and Abnormal sperm morphology % of smokerskcompared to control group (P>0.05). The same resultskwere obtained in diabetic and hypertensionkwhen compared tojcontrol group (P<0.05). Our resultsjindicated that thejdiabetes , hypertension and smoking reducelserum CK creatinine and semen parameters inkmale infertility . Enzymetic activity of CK inkserum is a biochemical marker in determining infertility and this biochemicalkmarker will represents an important diagnostic feature withmseminal parameters in the future.

Release of Neurosecretion in the Crayfish Sinus Gland

1968 ◽  
Vol 26 ◽  
pp. 150-151
Author(s):  
Richard R. Shivers
Keyword(s):  
Chemical Nature ◽  
Storage Site ◽  
Neurosecretory Granules ◽  
Sinus Gland ◽  
Diameter Class ◽  
Dense Membrane ◽  
Neurohemal Organ ◽  
Dense Vesicles

The sinus gland is a neurohemal organ located in the crayfish eyestalk and represents a storage site for neurohormones prior to their release into the circulation. The sinus gland contains 3 classes of dense, membrane-limited granules: 1) granules measuring less than 1000 Å in diameter, 2) granules measuring 1100-1400 Å in diameter, and 3) granules measuring 1500-2000 Å in diameter. Class 3 granules are the most electron-dense of the granules found in the sinus gland, while class 2 granules are the most abundant. Generally, all granules appear to undergo similar changes during release.Release of neurosecretory granules may be initiated by a preliminary fragmentation of the “parent granule” into smaller, less dense vesicles which measure about 350 Å in diameter (V, Figs. 1-3). A decrease in density of the granules prior to their fragmentation has been observed and may reflect a change in the chemical nature of the granule contents.

119: Effect of Epididymitis on Semen Biochemical and Sperm Morphology Parameters

2005 ◽  
Vol 173 (4S) ◽  
pp. 32-32
Author(s):  
Petra Huwe ◽  
Roelof Menkveld ◽  
Martin Ludwig ◽  
Wolfgang Weidner
Keyword(s):  
Sperm Morphology ◽  
Morphology Parameters

Instruction Helps and Hinders Young Children’s Feature Learning

2018 ◽  
Author(s):  
Charles Kalish ◽  
Nigel Noll
Keyword(s):  
Young Children ◽  
Feature Learning ◽  
Irrelevant Information ◽  
Diagnostic Feature ◽  
Older Children ◽  
Prediction Task ◽  
Feature Correlation ◽  
The Future

Existing research suggests that adults and older children experience a tradeoff where instruction and feedback help them solve a problem efficiently, but lead them to ignore currently irrelevant information that might be useful in the future. It is unclear whether young children experience the same tradeoff. Eighty-seven children (ages five- to eight-years) and 42 adults participated in supervised feature prediction tasks either with or without an instructional hint. Follow-up tasks assessed learning of feature correlations and feature frequencies. Younger children tended to learn frequencies of both relevant and irrelevant features without instruction, but not the diagnostic feature correlation needed for the prediction task. With instruction, younger children did learn the diagnostic feature correlation, but then failed to learn the frequencies of irrelevant features. Instruction helped older children learn the correlation without limiting attention to frequencies. Adults learned the diagnostic correlation even without instruction, but with instruction no longer learned about irrelevant frequencies. These results indicate that young children do show some costs of learning with instruction characteristic of older children and adults. However, they also receive some of the benefits. The current study illustrates just what those tradeoffs might be, and how they might change over development.

Do Sequential Lineups Impair Discriminability?

2020 ◽  
Author(s):  
Matthew Philip Kaesler ◽  
John C Dunn ◽  
Keith Ransom ◽  
Carolyn Semmler
Keyword(s):  
Human Behavior ◽  
Feature Detection ◽  
Eyewitness Memory ◽  
Simultaneous Presentation ◽  
Diagnostic Feature ◽  
Sequential Presentation ◽  
Sequential Lineups ◽  
Measurement Models ◽  
Sequential Lineup ◽  
Lineup Procedures

The debate regarding the best way to test and measure eyewitness memory has dominated the eyewitness literature for more than thirty years. We argue that to resolve this debate requires the development and application of appropriate measurement models. In this study we develop models of simultaneous and sequential lineup presentations and use these to compare the procedures in terms of discriminability and response bias. We tested a key prediction of the diagnostic feature detection hypothesis that discriminability should be greater for simultaneous than sequential lineups. We fit the models to the corpus of studies originally described by Palmer and Brewer (2012, Law and Human Behavior, 36(3), 247-255) and to data from a new experiment. The results of both investigations showed that discriminability did not differ between the two procedures, while responses were more conservative for sequential presentation compared to simultaneous presentation. We conclude that the two procedures do not differ in the efficiency with which they allow eyewitness memory to be expressed. We discuss the implications of this for the diagnostic feature detection hypothesis and other sequential lineup procedures used in current jurisdictions.

Molecular basis of adaptive evolution of sperm motility involved in in vivo fertilization of terrestrial animals

Impact ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 73-75
Author(s):  
Akihiko Watanabe
Keyword(s):  
Sexual Reproduction ◽  
Sperm Motility ◽  
Asexual Reproduction ◽  
Acrosome Reaction ◽  
Sperm Morphology ◽  
Adaptive Potential ◽  
Selective Pressures ◽  
The Face ◽  
Genetic Profiles

One of the unifying traits of life on this planet is reproduction, or life's ability to make copies of itself. The mode of reproduction has evolved over time, having almost certainly begun with simple asexual reproduction when the ancestral single celled organism divided into two. Since these beginnings' life has tried out numerous strategies, and perhaps one of the most important and successful has been sexual reproduction. This form of reproduction relies on the union of gametes, otherwise known as sperm and egg. Evolutionarily, sexual reproduction allows for greater adaptive potential because the genes of two unique individuals have a chance to recombine and mix in order to produce a new individual. Unlike asexual reproduction which produces genetically-identical clones of the parent individual, sex produces offspring with novel genes and combinations of genes. Therefore, in the face of new selective pressures there is a higher chance that one of these novel genetic profiles will produce an adaptation that is advantageous in the new circumstances. Dr Akihiko Watanabe is a reproductive biologist based in the Department of Biology, Faculty of Science Yamagata University in Japan, he is currently working on three research projects; a comparative study on the signalling pathways for inducing sperm motility and acrosome reaction in amphibians, the mechanism behind the adaptive modification of sperm morphology and motility, and the origin of sperm motility initiating substance (SMIS).

Sign in / Sign up

Export Citation Format

Share Document