scholarly journals Synopsis of rare fossil animal spermatozoa in amber and sedimentary deposits

2020 ◽  
Vol 191 ◽  
pp. 31
Author(s):  
Gérard Breton ◽  
George Poinar
Keyword(s):  
Sperm Transfer ◽  
Sperm Cells ◽  
Subcellular Organelles ◽  
Sedimentary Deposits ◽  
Preservation Medium

Fossil spermatozoa are extremely rare. Among the eight cases reported here, including two cases of spermatophores without visible sperm cells, six are fossils preserved in amber. All six concern animals with indirect sperm transfer by means of spermatophores or spermatodesmids. Preservation of subcellular organelles shows once again that amber is an extraordinary preservation medium.

Ultrastructure of Testicular Spermatozoon of the Fish Oreochromis Niloticus

1988 ◽  
Vol 46 ◽  
pp. 278-279
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Electron Microscope ◽  
Oreochromis Niloticus ◽  
Osmium Tetroxide ◽  
Sperm Cells ◽  
Adult Fish ◽  
Testicular Sperm ◽  
Thin Sections ◽  
Important Fish ◽  
Testicular Spermatozoon ◽  
Diamond Knife

Tilapia, Oreochromis niloticus, is an economically important fish in Saudi Arabia. Elucidation of reproductive biology of this species is necessary for successful breeding program. In this paper we describe fine structure of testicular sperm cells in O, niloticus.Testes from young adult fish were fixed in gluteraldehyde (2%) and osmium tetroxide (1%), both in cacodyl ate buffer. Specimens were processed in the conventional way for electron microscopy and thin sections of tissues (obtained by cutting the blocks with a diamond knife) were stained by ura- nyl acetate and lead citrate. These were examined in a Carl Zeiss electron microscope operated at 40 kV to 60 kV. Sperm cells were obtained from testes by squeezing them in cacodyl ate buffer. They were fixed in gluteraldehyde (2%) in the same buffer, air dried, gold coated and then examined in a Philips scanning electron microscope (SEM) operated at 25kV.The spermatozoon of O. niloticus is consisting of head, midpiece and tail (Fig. 1).

PATTERN OF 17-KETOSTEROID URINARY EXCRETION IN INFERTILE MEN

1963 ◽  
Vol 42 (1) ◽  
pp. 97-100
Author(s):  
Mirjam Furuhjelm ◽  
Birgit Johnson ◽  
C.-G. Lagergren
Keyword(s):  
Urinary Excretion ◽  
Sperm Cells ◽  
Infertile Men ◽  
Abnormal Cells

ABSTRACT The pattern of the 17-ketosteroid excretion determined according to Johnsen (1956) in a group of 33 sterile men was compared with that in another group of 14 men with proved fertility, and no difference was found. No correlation between 17-ketosteroid excretion and the concentration of sperm cells or the percentage of abnormal cells could be detected. The results are discussed.

Assemblies of D-peptides for Targeting Cell Nucleolus

2019 ◽  
Author(s):  
Huaimin Wang ◽  
Zhaoqianqi Feng ◽  
Weiyi Tan ◽  
Bing Xu
Keyword(s):  
Particle Morphology ◽  
Side Chain ◽  
Mechanism Study ◽  
Structural Analogue ◽  
Hydrophobic Residues ◽  
Subcellular Organelles ◽  
First Case ◽  
New Strategy ◽  
Peptide Derivative ◽  
Peptide Nanoparticles

<p>Selectively targeting cell nucleolus remains a challenge. Here we report the first case that D-peptides form membraneless molecular condensates with RNA for targeting cell nucleolus. A D-peptide derivative, enriched with lysine and hydrophobic residues, self-assembles to form nanoparticles, which enter cells through clathrin dependent endocytosis and mainly accumulate at cell nucleolus. Structural analogue of the D-peptide reveals that particle morphology of the assemblies, which depends on the side chain modification, favors the cellular uptake. Contrasting to those of the D-peptide, the assemblies of the corresponding L-enantiomer largely localize in cell lysosomes. Preliminary mechanism study suggests that the D-peptide nanoparticles interact with RNA to form membraneless condensates in the nucleolus, which further induces DNA damage and results in cell death. This work illustrates a new strategy for rationally designing supramolecular assemblies of D-peptides for targeting subcellular organelles.</p>

PROOXIDANT/ANTIOXIDANT BALANCE IN SPERM CELLS OF INFERTILE MEN

2018 ◽  
Vol 14 (66) ◽  
pp. 120
Author(s):  
R. V. Fafula ◽  
О. K. Оnufrovych ◽  
U. P. Iefremova ◽  
M. Z. Vorobets ◽  
I. A. Nakonechnyi ◽  
...  
Keyword(s):  
Sperm Cells ◽  
Infertile Men

The expression of Bax protein in the early stages of spinal cord injury in the sperm cells of rats

2018 ◽  
Author(s):  
Ayoob Rostamzadeh ◽  
◽  
Tayyeb Ghadimi ◽  
Azra Allahveisi ◽  
Mohsen Mohammadi ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Sperm Cells ◽  
Early Stages ◽  
Bax Protein ◽  
Cord Injury

The Chingandzha flora of the Okhotsk-Chukotka volcanic belt

Palaeobotany ◽  
2019 ◽  
Vol 10 ◽  
pp. 13-179
Author(s):  
L. B. Golovneva
Keyword(s):  
River Basin ◽  
Volcanic Belt ◽  
Flowering Plants ◽  
Sedimentary Deposits ◽  
North East ◽  
The North ◽  
Magadan Region ◽  
Chukotka Volcanic Belt ◽  
Systematic Composition ◽  
Coastal Lowlands

The Chingandzha flora comes from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, North-East of Russia). The main localities of the Chingandzha flora are situated in the Omsukchan district of the Magadan Region: on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River). The Chingandzha flora includes 23 genera and 33 species. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created. The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The main genera are Arctop teris, Osmunda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Protophyllocladus, Pseudoprotophyllum, Trochodendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. The Chingandzha flora is distinct from other floras of the Okhotsk-Chukotka volcanic belt (OCVB) in predominance of flowering plants and in absence of the Early Cretaceous relicts such as Podozamites, Phoenicopsis and cycadophytes. According to its systematic composition and palaeoecological features, the Chingandzha flora is similar to the Coniacian Kaivayam and Tylpegyrgynay floras of the North-East of Russia, which were distributed at coastal lowlands east of the mountain ridges of the OCVB. Therefore, the age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Kaivayam phase of the flora evolution and to the Anadyr Province of the Siberian-Canadian floristic realm. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul’ya flora of the Ul’ya Depression.

Sign in / Sign up

Export Citation Format

Share Document