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.

Sperm-cell ultrastructure of North American sturgeons. II. The shortnose sturgeon (Acipenser brevirostrum, Lesueur, 1818)

1999 ◽  
Vol 77 (2) ◽  
pp. 321-330 ◽  
Author(s):  
Martin N DiLauro ◽  
Wayne S Kaboord ◽  
Rosemary A Walsh
Keyword(s):  
Sperm Cell ◽  
Cell Ultrastructure ◽  
Sperm Cells ◽  
Shortnose Sturgeon ◽  
Atlantic Sturgeon ◽  
Head Region ◽  
Acipenser Brevirostrum ◽  
Transmission Electron ◽  
Structural Connection ◽  
Single Flagellum

The fine structure of the sperm cell of the shortnose sturgeon (Acipenser brevirostrum) was examined using transmission electron microscopy and selected metrics. The cell possesses a distinct acrosome, a defined head region, a midpiece, and a single flagellum. The mean length of the sperm cell body (acrosome + nucleus + midpiece) is approximately 9.71 µm, and the length of the flagellum is about 37 µm, resulting in a total cell length of about 46 µm. The sperm cell of the shortnose sturgeon is much longer and slightly wider than that of the Atlantic sturgeon. The nuclei of shortnose, white, and stellate sturgeon sperm cells are elongate trapezoids with the anterior (acrosome) end narrowest, the opposite of that of the Atlantic sturgeon. Although slightly smaller in total length and width than the sperm cells of the stellate and white sturgeons, that of the shortnose sturgeon is most similar to them in overall ultrastructure, as all three cells have three endonuclear canals. A structural connection of unknown function between the nuclear fossa and the proximal centriole, which is similar to the fibrous body in other species, is present in the shortnose sturgeon sperm cell. Our results suggest a more recent evolutionary link between the shortnose, white, and stellate sturgeons than between any of these and the Atlantic sturgeon. This is the first description of sperm cell ultrastructure in the shortnose sturgeon, an endangered species.

Sperm-cell ultrastructure of North American sturgeons. I. The Atlantic sturgeon (Acipenser oxyrhynchus)

1998 ◽  
Vol 76 (10) ◽  
pp. 1822-1836 ◽  
Author(s):  
Martin N DiLauro ◽  
Wayne Kaboord ◽  
Rosemary A Walsh ◽  
William F Krise ◽  
Michael A Hendrix
Keyword(s):  
Electron Microscopy ◽  
Sperm Cell ◽  
Evolutionary Relationship ◽  
Lake Sturgeon ◽  
White Sturgeon ◽  
Evolutionary Relationships ◽  
Head Width ◽  
Sperm Cells ◽  
Atlantic Sturgeon ◽  
Stellate Sturgeon

Atlantic sturgeon (Acipenser oxyrhynchus) and lake sturgeon (Acipenser fulvescens) sperm-cell morphologies were examined using scanning electron microscopy. Major differences were found in four of nine metrics, all in the head region of the cell. Atlantic sturgeon sperm cells were much shorter than those of lake sturgeon. Anterior head width exceeded posterior head width, in contrast to the arrangement in lake sturgeon sperm cells. Lake sturgeon sperm cells are nearer in size to those of other sturgeons than are Atlantic sturgeon sperm cells. Comparisons were made with sperm-cell structures known from other sturgeon species, including the Russian sturgeon (Acipenser gueldenstaedti colchicus), stellate sturgeon (Acipenser stellatus), Chinese sturgeon (Acipenser sinensis), and white sturgeon (Acipenser transmontanus). Variation in cell morphology may indicate evolutionary relationships. In addition, the fine structure of Atlantic sturgeon sperm cells was examined using transmission electron microscopy and selected metrics are described. The cell possesses a distinct acrosome, a midpiece, and a single flagellum. A comparison is made with ultrastructural details of the sperm cells of stellate and white sturgeons. Similarities among these species include radial symmetry about the longitudinal axis, an elongate shape, a distinct acrosome, and the presence of endonuclear canals. Noteworthy differences include a smaller total length and width than stellate and white sturgeon sperm cells. The main sperm-cell body is approximately 4 µm long and the flagellum about 37 µm long, resulting in a total cell length of about 41 µm. Also, the Atlantic sturgeon sperm cell possesses only two membraned endonuclear canals, in contrast to the arrangement in white and stellate sturgeons, where three such organelles are found. A structural connection of unknown function between the nuclear fossa and proximal centriole is also present in the Atlantic sturgeon sperm cell. Sperm-cell nuclei of white and stellate sturgeons are elongate trapezoids, with the anterior end narrower, whereas in Atlantic sturgeon the anterior portion of the trapezoid is wider than the posterior. Structural similarities between species may indicate a commonality of ancestral and evolutionary relationships that may have taxonomic implications. Ultrastructure suggests a closer evolutionary relationship between the white and stellate sturgeon than between either of these species and the Atlantic sturgeon. The present findings may be used by biologists studying the reproductive physiology, forensics, taxonomy, and genetics of sturgeons.

Biology, Management, and Protection of North American Sturgeon

2002 ◽  
Keyword(s):  
North American ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Shortnose Sturgeon ◽  
Fish Size ◽  
Laboratory Flume ◽  
Approach Velocity ◽  
Young Of The Year ◽  
American Sturgeon

<em>Abstract.</em>—We evaluated the ability of juvenile lake sturgeon <em>Acipenser fulvescens</em> and shortnose sturgeon <em>A. brevirostrum</em> to guide along various configurations of angled bar racks and louvers in a laboratory flume. Young-of-the-year (YOY) lake sturgeon were evaluated with the guidance arrays angled at 45 and 15 degrees to the approach flow, and age-1 lake and shortnose sturgeon were evaluated only with the guidance structures set at a 15 degree angle. The YOY lake sturgeon, also, were evaluated with a perpendicular bar rack and with no guidance structure in place. We estimated guidance efficiency at three approach velocities (0.3, 0.6, and 0.9 m/s) by determining the percentage of released fish that were diverted to a full-depth bypass. Guidance efficiency of YOY lake sturgeon was low (<37%) for all bar rack and louver configurations evaluated. The highest guidance efficiencies for YOY lake sturgeon occurred at an approach velocity of 0.3 m/s, and the lowest guidance levels were observed at 0.9 m/s. All YOY lake sturgeon were entrained (i.e., 0% guidance) during tests with the perpendicular bar rack and with no guidance structure in place. There was little difference in YOY lake sturgeon guidance efficiency rates among the various configurations of angled bar racks and louvers that were evaluated with respect to slat spacing, structure angle, and the presence or absence of a solid overlay on the bottom 30 cm of the guidance structures angled at 15 degrees to the approach flow. Guidance efficiencies for age-1 lake and shortnose sturgeon were high, exceeding 90% at all velocities, during tests of the 15-degree bar racks and louvers with the solid bottom overlay installed. The lowest shortnose sturgeon guidance efficiency (83.3%) occurred during the evaluation of the louver without the overlay in place at a velocity of 0.6 m/s. The large difference in guidance rates between the YOY lake sturgeon and the age-1 lake and shortnose sturgeon was most likely due to swimming capabilities associated with fish size. Based on the sizes of the fish we evaluated, the use of angled bar racks and louvers may not be appropriate for sturgeons less than about 200 mm in length, whereas they may be viable guidance technologies for larger fish.

Sperm-cell ultrastructure of North American sturgeons. IV. The pallid sturgeon (Scaphirhynchus albus Forbes and Richardson, 1905)

2001 ◽  
Vol 79 (5) ◽  
pp. 802-808 ◽  
Author(s):  
Martin N DiLauro ◽  
Rosemary A Walsh ◽  
Michelle Peiffer ◽  
Randy M Bennett
Keyword(s):  
Sperm Cell ◽  
Longitudinal Axis ◽  
Cell Ultrastructure ◽  
Sperm Cells ◽  
Atlantic Sturgeon ◽  
Ultrastructural Studies ◽  
Pallid Sturgeon ◽  
Oak Tree ◽  
Distal Centriole ◽  
Scaphirhynchus Albus

Sperm-cell morphology and ultrastructure in the pallid sturgeon (Scaphirhynchus albus) were examined using transmission and scanning electron microscopy. Metrics and structure were compared with similar metrics obtained from other published descriptions of sturgeon sperm cells. General morphology was found to be similar to that of sperm cells of the white (Acipenser transmontanus), lake (A. fulvescens), stellate (A. stellatus), Chinese (A. sinensis), Russian (A. gueldenstaedti colchicus), and shortnose (A. brevirostrum) sturgeons, which all shared a gradual tapering of the nuclear diameter from posterior to anterior, unlike that of the Atlantic sturgeon (A. oxyrhynchus). The sperm cell of the pallid sturgeon was similar in size to that of the Atlantic sturgeon, being only slightly larger. The sperm cell of the pallid sturgeon differed from those of other sturgeons chiefly in the acrosomal region, where the posterolateral projections (PLP) have the shape of an acute triangle and are arranged in a spiral about the longitudinal axis of the cell. The PLP were longer than those of other sturgeons, being twice the length of those of the Atlantic sturgeon and 58% longer than those of the lake sturgeon. Also, in cross section the acrosome had the shape of a hollow cone rather than the cap of an oak tree acorn, as was found in ultrastructural studies of other sturgeons. In addition, we were able to confirm that the structural arrangement of the distal centriole of the midpiece is identical with that of the proximal centriole: nine sets of microtubular triplets around the periphery of the centriole. This information is of potential use to fishery biologists, forensic biologists, zoologists, reproductive physiologists, taxonomists, evolutionary biologists, and aquaculturists.

The nuclear envelope protein KAKU4 determines the migration order of the vegetative nucleus and sperm cells in pollen tubes

2020 ◽  
Vol 71 (20) ◽  
pp. 6273-6281 ◽  
Author(s):  
Chieko Goto ◽  
Kentaro Tamura ◽  
Satsuki Nishimaki ◽  
Daisuke Maruyama ◽  
Ikuko Hara-Nishimura
Keyword(s):  
Sperm Cell ◽  
Pollen Grains ◽  
Nuclear Lamina ◽  
Pollen Tubes ◽  
Pollen Grain ◽  
Vegetative Nucleus ◽  
Sperm Cells ◽  
Wild Type ◽  
Cell Nuclei ◽  
In The Wild

Abstract A putative component protein of the nuclear lamina, KAKU4, modulates nuclear morphology in Arabidopsis thaliana seedlings, but its physiological significance is unknown. KAKU4 was highly expressed in mature pollen grains, each of which has a vegetative cell and two sperm cells. KAKU4 protein was highly abundant on the envelopes of vegetative nuclei and less abundant on the envelopes of sperm cell nuclei in pollen grains and elongating pollen tubes. Vegetative nuclei are irregularly shaped in wild-type pollen. However, KAKU4 deficiency caused them to become more spherical. After a pollen grain germinates, the vegetative nuclei and sperm cells enter and move along the pollen tube. In the wild type, the vegetative nucleus preceded the sperm cell nuclei in &gt;90% of the pollen tubes, whereas, in kaku4 mutants, the vegetative nucleus preceded the sperm cell nuclei in only about half of the pollen tubes. kaku4 pollen was less competitive for fertilization than wild-type pollen after pollination. These results led us to hypothesize that the nuclear shape in vegetative cells of pollen grains affects the orderly migration of the vegetative nucleus and sperm cells in pollen tubes.

scholarly journals New Spirinia and Stygodesmodora species (Nematoda, Spiriniinae) from the Southwest Pacific, and a revision of the related genera Spirinia, Chromaspirina and Perspiria

2015 ◽  
Author(s):  
Daniel Leduc ◽  
Dominick Verschelde
Keyword(s):  
New Species ◽  
Buccal Cavity ◽  
Sperm Cells ◽  
Head Region ◽  
Anterior Portion ◽  
Southwest Pacific ◽  
The Family ◽  
Two New Species ◽  
Short Body ◽  
Size And Structure

Two new species of the family Desmodoridae are described from the upper continental slope of New Zealand, Southwest Pacific, and the genera Spirinia, Chromaspirina and Perspiria are revised. Spirinia verecunda sp. nov. is characterised by a short, stout body, cuticle covered in minute, hair-like structures, unispiral amphideal aperture and cryptospiral amphideal fovea, buccal cavity with small dorsal tooth and minute subventral teeth, eight oblong glands surrounding anterior portion of pharynx, large sperm cells, spicules with weak capitulum, and the absence of precloacal supplements. Stygodesmodora confusa sp. nov. is characterised by a relatively short body, spiral amphids with 1.2–1.4 turns, cephalic setae situated at or slightly posterior to mid-level of amphid, and males with four precloacal supplements consisting of short setae on wide bases. Like other species of the genus, S. confusa sp. nov. is characterised by an annulated head region, but in some specimens the cuticle annulations are restricted to the dorsal and ventral sides of the head. S. confusa sp. nov. shows similarities with species of other desmodorid genera (i.e., Echinodesmodora, Bolbonema), but can be differentiated from them by the presence of an annulated head region and amphideal plates. The genera Spirinia, Chromaspirina and Perspiria have very similar morphologies and differ mainly in the size and structure of the buccal cavity (Spirinia vs Chromaspirina) or the shape of the tail and placement of the amphids relative to the cuticle annulations (Spirinia vs Perspiria); their diagnoses are clarified and some nomenclatural changes are proposed to eliminate overlap in the definitions of these genera.

scholarly journals Response in Growth, Scute Development, and Whole-Body Ion Composition of Acipenser fulvescens Reared in Water of Differing Chemistries

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1419
Author(s):  
Janet Genz ◽  
Rachael Hicks
Keyword(s):  
River Water ◽  
Growth And Development ◽  
Lake Sturgeon ◽  
Whole Body ◽  
Acipenser Fulvescens ◽  
Water Type ◽  
Ion Composition ◽  
Ion Concentrations ◽  
Before And After ◽  
Yolk Absorption

In fishes, environmental ion availability can have substantial effects on growth and development. This study examined the development of Lake Sturgeon in response to the varying environmental ion availability that they experience as part of a conservation stocking program. We reared sturgeon in natural water from the Coosa River, which had higher concentrations of Mg2+, Na+, and Zn2+ than standard hatchery conditions, while [Ca2+] at the Warm Springs National Fish Hatchery was 2× higher than in the Coosa River. Eggs were hatched in each water type and the larvae were sampled at time points before and after yolk absorption during the first 8 weeks of development. Total length and weight in WSNFH larvae were significantly higher than larvae in Coosa River water starting at 8 dph, indicating that growth was dependent on the different environmental ion levels. Concentrations of the ions of interest were also determined for whole-body acid digests of the exposed Lake Sturgeon. We found that Lake Sturgeon reared in Coosa River water had significantly higher magnesium and zinc than Lake Sturgeon reared in WSNFH water (p < 0.05), while calcium was significantly higher in WSNFH than Coosa River water. This difference shows that different environmental ion concentrations also impact the overall development of larval Lake Sturgeon.

scholarly journals Persistent directional growth capability in Arabidopsis thaliana pollen tubes after nuclear elimination from the apex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kazuki Motomura ◽  
Hidenori Takeuchi ◽  
Michitaka Notaguchi ◽  
Haruna Tsuchi ◽  
Atsushi Takeda ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Sperm Cell ◽  
Pollen Tubes ◽  
Vegetative Nucleus ◽  
Sperm Cells ◽  
Apical Region ◽  
Basal Region ◽  
Specific Expression ◽  
Directional Growth

AbstractDuring the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.

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