Coiling of the Flagellar Shaft in the Head Region of the Mature Sperm of Nucella (Purpura) Lapillus (L.)

1969 ◽  
Vol 5 (1) ◽  
pp. 211-225
Author(s):  
MURIEL WALKER
Keyword(s):  
Sea Water ◽  
Nuclear Material ◽  
Sperm Nucleus ◽  
Mature Sperm ◽  
Langmuir Trough ◽  
Head Region ◽  
Anterior Portion ◽  
Normal Concentration ◽  
Ph Range ◽  
Dry Out

The sperm of Nucella are long and threadlike. The flagellar shaft runs from the acrosome at the front of the head to the tip of the tail. Its anterior portion, the head shaft, is ensheathed by the nucleus. If a suspension of sperm in normal-concentration sea water is observed under phase contrast, and allowed to dry out slowly, the nuclear material of sperm near the edge of the coverglass swells and the head shafts of these sperm are thrown into gentle spirals within the nuclei. In some sperm the nuclear material disperses completely, and the front threequarters of the head shaft springs into a tight right-handed coil of 5-7 turns. Instantaneous coiling of the head shaft may also be induced by treatment of the sperm with x 2 concentrated sea water or 0.01 % (w/v) solution of sodium lauryl sulphate in sea water. The enzymes pronase and trypsin at a concentration of 50µg/ml in sea water at pH 8.0 cause dispersion of the head nucleoprotein and subsequently the head shaft forms a loose coil. The appearance and activity of the sperm do not change perceptibly over a pH range of 5.5-8.5. Sperm spread on a Langmuir trough containing normal concentration sea water were negatively stained with phosphotungstic acid and examined with an electron microscope. After such treatment the nuclei are partially spread and the fibrils of the head shafts appear twisted as the wires of an electrical flex. The twisted flagellar fibrils are seen more clearly in negatively stained head shafts of sperm whose nuclei have been completely dispersed by spreading on a Langmuir trough containing x2 concentrated sea water. Negatively stained preparations of sperm treated with enzymes show sperm with twisted and coiled head shafts. The nucleoprotein of these sperm is disaggregated into strips or sheets, or may appear as a mass of branching fibres. The flagellar fibres of the enzyme-treated sperm are often bent or broken. Longitudinal sections of mature sperm heads show that in the intact sperm the fibres of the head shaft are not twisted but run straight throughout the length of the head. Sections from the testis and testicular duct show that microtubules are present in sperm in the testis but absent from mature sperm in the testicular duct. It is suggested that the head shaft, as a consequence of some event in spermiogenesis, has an inherent tendency to twist and coil but in the mature sperm it is ‘strait-jacketed’ by the sperm nucleus.

Comparative spermatology of 11 species of Polyplacophora (Mollusca) from the suborders Lepidopleurina, Chitonina and Acanthochitonina

1988 ◽  
Vol 235 (1279) ◽  
pp. 161-177 ◽  
Keyword(s):  
Electron Microscopy ◽  
Morphological Changes ◽  
Chromatin Condensation ◽  
Nuclear Material ◽  
Taxonomic Character ◽  
Anterior Portion ◽  
Preliminary Examination ◽  
Transmission Electron ◽  
Species Specific ◽  
Egg Coat

Transmission electron microscopy of the spermatozoa and spermatogenesis of 11 species (in three suborders Chitonina, Acanthochitonina, Lepidopleurina) of chiton has shown that each species has a sperm with a unique morphology indicating that spermatozoa can be used as a taxonomic character. Although structure is species-specific, similarities between species within suborders and subfamilies can be recognized. The spermatozoa of species from the suborders Chitonina and Acanthochitonina have a head comprising nuclear material only, the anterior portion of which is in the form of a long thin (approximately 80 nm diameter) filament. In many species the centrioles and mitochondria of the mid-piece are lateral in position, the mitochondria often being sited anteriorly alongside the nucleus. By contrast, Leptochiton asellus , a member of the more ancient suborder Lepidopleurina, has a sperm with a head comprising a nucleus and an acrosome. The mid-piece is also more conven­tional in structure with a ring of five or six spherical mitochondria (sited behind the nucleus) that surround the centrioles. The presence of the acrosome in L. asellus suggests that in the more recent chitons the acro­some has been secondarily lost. It is proposed that loss of the acrosome is correlated to a modification in egg-coat thickness. A preliminary examination of the structure of the eggs of three species has shown that those of L. asellus are surrounded by a very thick chorion (14-30 μm) whereas in Acanthochitona crinitus and Dinoplax gigas there are regions of the chorion that are less than 2 μm thick. The morphological changes that occur during spermatogenesis are very similar in the Chitonina and Acanthochitonina. During spermiogenesis the nucleus elongates to develop a long anterior filament. Chro­matin condensation within the nucleus involves the formation of fibrils that become orientated along its long axis. Closely associated with the elongating nucleus is a manchette. In L . asellus a spherical proacrosomal vesicle appears in the spermatocytes. This vesicle becomes compressed as it matures and simultaneously it migrates to the presumptive anterior end of the spermatid where it invaginates and elongates. Although the pattern of chromatin condensation in the nucleus is similar to that described above, a manchette has not been observed.

scholarly journals AN ANALYSIS OF THE INACTIVATION OF THE FROG SPERM NUCLEUS BY TOLUIDINE BLUE

1952 ◽  
Vol 35 (5) ◽  
pp. 761-780 ◽  
Author(s):  
Robert Briggs
Keyword(s):  
Toluidine Blue ◽  
Sperm Nucleus ◽  
Sperm Cells ◽  
Dye Molecules ◽  
Ph Measurements ◽  
Complete Inactivation ◽  
Minimal Quantity ◽  
Sperm Nuclei ◽  
Sperm Chromosomes ◽  
Ph Range

Toluidine blue, applied to frog sperm under appropriate conditions, inactivates specifically the sperm nucleus, leaving the extranuclear parts of the cell undamaged. Thus, the dye-treated spermatozoa stimulate eggs to cleave normally, but contribute no chromosomes to the resulting embryos, which develop as typical gynogenetic haploids. The concentration of dye required to produce this inactivation varies with pH. Measurements made over the entire pH range which can be tolerated by sperm cells showed that in the lower part of the range (5 to 7) the effective dye concentration was about 5 x 10–6 M; in the intermediate range (7 to 8.5) it was 1 x –6 to 1 x –7 M; and for the higher pH values (8.5 to 10.0) it was about 5 x –8 M. Using sperm suspensions containing 1500 cells per c. mm. these concentrations of dye produced specific inactivation of the sperm nuclei within 7 to 60 minutes at 18°C. Tests of the reversibility of the inactivation were made by transferring the sperm from the dye to a dilute Ringer's solution after a known degree of inactivation had been produced. Following removal of the dye the sperm cells were tested on eggs over a period of 2 hours. During this time there was no indication of a reversal of the inactivation. Microscopic observations of sperm treated with –5 M or 5 X –5 M dye show that the dye is taken up by the sperm nucleus, which is faintly but definitely stained. The dye appears to be uniformly distributed in the nucleus, while extranuclear structures remain unstained. Measurements of the amount of dye bound per sperm nucleus indicate that the minimal quantity required for complete inactivation is about 6.7 x –18 mole, while the maximal amount which can be bound without injury to extranuclear structures is about 1.5 x –16 mole. The value obtained for the minimal requirement (6.7 X 16 mole = 4 X 6 molecules) suggests that there are roughly 4 million binding sites in the nucleus which, when blocked by dye molecules, somehow prevent the sperm chromosomes from participating in the development of the egg.

Meloidogyne brasilensis n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitising tomato cv. Rossol in Brazil

Nematology ◽  
2002 ◽  
Vol 4 (5) ◽  
pp. 629-643 ◽  
Author(s):  
Jonathan Eisenback ◽  
João Charchar
Keyword(s):  
Excretory Pore ◽  
Root Knot Nematode ◽  
Head Region ◽  
Anterior Portion ◽  
Second Stage ◽  
Stage Juvenile ◽  
High Head ◽  
Labial Disc ◽  
Very High

AbstractMeloidogyne brasilensis n. sp., Londrina and Brasilia populations, is described and illustrated from specimens from tomato cv. Rossol and pea cv. Mikado, respectively, in Brazil. Characteristically, the perineal pattern is elongated to ovoid with a flattened to very high, squarish dorsal arch with widely spaced, coarse striae. The lateral fields may have wing-like striae on one or both sides. The female stylet is 14 μm long with narrow and elongated knobs that are distinctly set-off from the shaft. The excretory pore is variable in location, but generally opens near the anterior portion of the median bulb about 50 μm from the head end. The male is 1.89 mm long and has a high head cap that slopes posteriorly. The labial disc is separated from the medial lips by a deep, rounded groove. The delicate stylet of the male is 23 μm long and has small, rounded knobs that are distinctly set-off from the shaft which has numerous small, rounded projections. Mean second-stage juvenile length is 434 μm. The juvenile head cap is highly elevated, the medial lips are crescent-shaped and unequal in size, and the head region is not annulated. The stylet is 11 μm long and has small, rounded, posteriorly sloping knobs. The tail is 53 μm long; it is marked with large, irregular annules and ends in a bluntly rounded tip. The hyaline tail terminus is short (13 μm). Reproduction occurred on NC95 tobacco, tomato, pea, and bean, whereas pepper, watermelon, peanut, cotton, corn, and soybean were not hosts.

Nuclear Morphogenesis During Spermiogenesis in the Pulmonate Snail Lymnaea Stagnalis

1968 ◽  
Vol 26 ◽  
pp. 130-131
Author(s):  
James Ihle ◽  
Walter J. Humphreys
Keyword(s):  
Nuclear Membrane ◽  
Lymnaea Stagnalis ◽  
Nuclear Material ◽  
Sperm Nucleus ◽  
Current Work ◽  
Exact Nature ◽  
Pulmonate Snail ◽  
Early Stages ◽  
Nuclear Changes ◽  
Otala Lactea

A study by Rebhun on nuclear changes during spermiogenesis in the pulmonate snail Otala lactea has presented evidence that nuclear elongation is accompanied by orientation of nuclear material into 60 A° sheets. The exact nature of the formation of these sheets, however, was not ascertained. In current work on gametogenesis in the pulmonate snail Lymnaea stagnalis observations were made of nuclear morphogenesis which describes this process.The nucleus of a Lymnaea spermatid is spheriod or somewhat ellipsoidal in the early stages of differentiation. The karoplasm consists of a nonhomogeneous matrix of granules. Thereafter, the shape of the nucleus changes to that of an oblate spheriod. The granular nuclear material becomes fibrous in nature and is either clumped together or randomly dispersed in the karoplasm. The nuclear membrane becomes thickened at the prospective anterior and posterior regions of the sperm nucleus.

Spermatogenesis and the Structure of the Mature Sperm in Nucella Lapillus (L)

1968 ◽  
Vol 3 (1) ◽  
pp. 95-104
Author(s):  
MURIEL WALKER ◽  
H. C. MACGREGOR
Keyword(s):  
Golgi Complex ◽  
Mature Sperm ◽  
Mitochondrial Membranes ◽  
Fast Green ◽  
Anterior Portion ◽  
Front End ◽  
Early Spermatid ◽  
Before And After ◽  
Spermatid Nucleus ◽  
Pass Through

The testis of Nucella consists of numerous tubules, all directed inwards and joining to form a common testicular duct. In a single tubule the spermatogonia lie round the periphery. Mature sperm line the lumen of the tubule. Cells in the same stage of spermatogenesis are grouped together and all members of a group pass through spermatogenesis in phase. Staining with fast green before and after treatment with Van Slyke reagent indicates a change from lysine-rich to arginine-rich histone in the maturing spermatid. Sperm of Nucella are motile throughout their length. The sperm are thread-like and about 80 µ long. The head is Feulgen-positive and about 40 µ long. The mid-piece lies behind the head and is about 8 µ long. The flagellum runs from the front end of the head to the tip of the tail; in the head it is completely surrounded by the nucleus. The spermatogonia contain two centrioles situated near the nucleus and a conspicuous Golgi complex. There are synaptinemal complexes in spermatocyte nuclei in the synapsis stage. In the early spermatid the centriole pushes a tube through the nucleus. This tube is lined by nuclear membrane and is occupied by the anterior portion of the flagellar shaft. The nucleus elongates and the nucleoprotein condenses into strands arranged helically along the long axis of the nucleus. These strands fuse to form lamellae, which disappear in the mature sperm. Mitochondria aggregate at the base of the early spermatid nucleus and form a loose spiral around the flagellar shaft. The outer mitochondrial membranes fuse. The mid-piece of the mature sperm consists of a large tubular mitochondrion enclosing a portion of the flagellar shaft. At the early spermatid stage a pro-acrosomal granule is formed from a large Golgi complex. From this the acrosome develops; it consists of a cone and an acrosome granule. There are two sets of microtubules associated with the acrosome, one lying within the cone, the other outside the cone and separated from it by a ‘ragged membrane’. The microtubules of the outer set extend backwards along the head for two-thirds of its length. The centriole which gives rise to the flagellar shaft lies at the anterior end of the head and is separated from the acrosome by a thin layer of nucleoprotein and a double layer of nuclear envelope. There is no second centriole or derivative thereof in the mature sperm. In the tail groups of coiled fibres are associated with each pair of the peripheral flagellar fibrils.

scholarly journals Oxidation-Reduction Potential in Sea Water

1937 ◽  
Vol 22 (1) ◽  
pp. 167-176 ◽  
Author(s):  
L. H. N. Cooper
Keyword(s):  
Reduction Potential ◽  
Sea Water ◽  
Freezing Point ◽  
Oxygen Electrode ◽  
Electrode Potentials ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Typical Data ◽  
Hydroxyl Ion ◽  
Ph Range

The activity of oxygen in sea water and standard oxygen electrode potentials at a range of temperatures have been computed.Accurate values for the thermodynamic ionic product of water, Kw, found by Harned & Hamer, have been applied to the calculation of the activity of hydroxyl ion in sea water from pH measurements.The activity of water in sea water has been computed from the lowering of the freezing-point.From these data the theoretical reversible oxidation-reduction potential of sea water has been calculated..Typical data for the irreversible potential in the pH range 1-8 have been derived from Hoar's results with which experimental determinations made by Dr Atkins agree. Thus the oxidation-reduction potential of sea water is controlled solely by the oxygen system.

Water quality characteristics of Densu River basin in south-east Ghana

2010 ◽  
Vol 61 (6) ◽  
pp. 1467-1477 ◽  
Author(s):  
J. Amoako ◽  
A. Y. Karikari ◽  
O. D. Ansa-Asare ◽  
E. Adu-Ofori
Keyword(s):  
Water Quality ◽  
Sea Water ◽  
Background Level ◽  
Water Quality Monitoring ◽  
Natural Background ◽  
Nitrogen And Phosphorus ◽  
Background Values ◽  
Physico Chemical ◽  
Ph Range ◽  
Dominance Pattern

Water quality of the Densu River was studied by determining the levels of various physico-chemical parameters including trace metals for planning of the basin. The pH range (7.40–8.22) fell within the natural background level 6.5–8.5. The river was moderately hard with high turbidity due to poor farming practices, which result in large quantities of topsoil ending up in the river after rains. The river waters were well oxygenated with a mean DO concentration of 6.3 mg/l. Nitrogen and phosphorus levels were below their natural background values. The Densu River showed an overall ionic dominance pattern of Na > Ca  > K > Mg and Cl > HCO3 > SO4, a pattern which is an intermediate between fresh and sea water systems. The mean concentrations of metals for the basin followed the order: Fe > Mn > Zn > Pb > Cu > Cd. 84.6% of the sampling sites exceeded the background values of 0.3 mg/l and 0.1 mg/l for Fe and Mn respectively. Other metals Zn, Pb, Cu and Cd were all below their background levels indicating the river is unpolluted with respect to these metals. Water Quality index performed on the data depicted that River Densu is of poor to fairly good water quality. Regular water quality monitoring is recommended.

Sperm-cell ultrastructure of North American sturgeons. III. The lake sturgeon (Acipenser fulvescens Rafinesque, 1817)

2000 ◽  
Vol 78 (3) ◽  
pp. 438-447 ◽  
Author(s):  
Martin N DiLauro ◽  
Wayne S Kaboord ◽  
Rosemary A Walsh
Keyword(s):  
Sperm Cell ◽  
Radial Symmetry ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Sperm Cells ◽  
Shortnose Sturgeon ◽  
Atlantic Sturgeon ◽  
Cell Nuclei ◽  
Head Region ◽  
Anterior Portion

Lake sturgeon (Acipenser fulvescens) sperm cell fine structure was examined using transmission electron microscopy. The cell possesses a distinct acrosome, a defined head region, a midpiece, and a single flagellum. Sperm cells of this species share a general radial symmetry, an elongate shape, a distinct acrosome, and the presence of endonuclear canals with those of other sturgeons. The mean length of the lake sturgeon sperm cell body (acrosome + nucleus + midpiece) is approximately 7.13 µm and the length of the flagellum is about 50 µm, resulting in a total cell length of about 57 µm. The lake sturgeon sperm cell is much longer and slightly wider than that of the Atlantic sturgeon. The sperm-cell nuclei of lake, shortnose, white, and stellate sturgeons are elongate trapezoids in shape, with the anterior (acrosome) end narrowest but, in the Atlantic sturgeon, the anterior portion of the trapezoid is wider than the posterior. Although slightly smaller in total length and width, the lake sturgeon sperm cell is most similar to the shortnose sperm cell in ultrastructure, overall size, and shape; it also shares similarity of shape with the stellate and white sturgeon sperm cells. The cell nuclei of these four sturgeons have three endonuclear canals. The acrosome of the lake sturgeon sperm cell has longer posterolateral projections than that of the Atlantic or shortnose sturgeon sperm cell. A structural connection, the fibrous body, is present in the lake sturgeon sperm cell between the nuclear fossa and the proximal centriole, as in the Atlantic and shortnose sturgeon sperm cells. Our results suggest a more recent evolutionary linkage between the lake and shortnose sturgeons than with the Atlantic sturgeon. This work presents the first ultrastructural description of the lake sturgeon sperm cell.

scholarly journals The effect of immersion with time and water variations on bending strength of malapoga wood (Toona Ciliata M. Roem)

2020 ◽  
Vol 331 ◽  
pp. 05003
Author(s):  
Awal Sirajuddin Syahrani ◽  
Alimuddin Sam ◽  
Basri
Keyword(s):  
River Water ◽  
Brackish Water ◽  
Test Specimen ◽  
Bending Strength ◽  
Sea Water ◽  
Testing Procedure ◽  
Test Results ◽  
Main Ingredient ◽  
Toona Ciliata ◽  
Dry Out

Bending strength is a parameter used in wood structure planning. The purpose of this study was to determine the effect of time and water of immersion on increasing bending strength. The main ingredient of this research is malapoga wood (Toona Ciliata M. Roem) which was previously preserved by immersion with brackish water, sea water and river for 2,4,6 and 8 weeks. Bending strength specimen and testing procedure refer to ASTM D14. A cross section of the test specimen is then subjected to a macro photograph to determine its failure mechanism. The test results show that Immersion using river water gives a greater bending strength value followed by using brackish water and sea water. The maximum bending strength of the river water is 26. 64 MPa at the time of immersion 4 weeks later followed by brackish water at 25. 86 MPa while the maximum bending strength value of seawater occurs in immersion for 6 weeks which is 24. 52 MPa. The immersion time causes the malapoga wood to become denser due to all the cavities in the malapoga wood filled with material contained in brackish water, sea and river so that the fibers of malapoga wood close up, dry out and crystallize inside the malapoga wood cavity which causes the bending strength of malapoga to increase.

scholarly journals Reniform Nematode, Rotylenchulus reniformis Linford & Oliveira (Nematoda: Tylenchida: Tylenchoidea: Hoplolaimidae: Rotylenchulinae)

EDIS ◽  
1969 ◽  
Vol 2004 (9) ◽  
Author(s):  
Koon-Hui Wang
Keyword(s):  
The Body ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Tail Region ◽  
Head Region ◽  
Anterior Portion ◽  
Root Cortex ◽  
Important Species ◽  
Posterior Portion ◽  
Feeding Site

Reniform nematodes in the genus Rotylenchulus are semiendoparasitic (partially inside roots) species in which the females penetrate the root cortex, establish a permanent-feeding site in the stele region of the root and become sedentary or immobile. The anterior portion (head region) of the body remains embedded in the root whereas the posterior portion (tail region) protrudes from the root surface and swells during maturation. The term 'reniform' refers to the kidney-shaped body of the mature female. There are ten species in the genus Rotylenchulus. Rotylenchulus reniformis is the most economically important species (Robinson 1997 ) and is called the reniform nematode. This document is EENY-210, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: May 2001.  EENY-210/IN367: Reniform Nematode, Rotylenchulus reniformis Linford and Oliveira (Nematoda: Tylenchida: Tylenchoidea: Hoplolaimidae: Rotylenchulinae) (ufl.edu)

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