bluuebunny/crossref_metadata_2025 huggingface dataset:
Dimensionality and contractile vacuole function in ciliated protozoa
Authors: Lynn Denis H.
Published: June 2005

It is believed by some (Günther, '75a) that the dimensional theory of biological similarity is somehow not appropriate at the microscopic and cellular levels. The results of the present study of contractile vacuoles of ciliated protozoa, ranging in length from 25 to 150 μm, sugggests, however, that the theory is appropiate. The data demonstrate that 1)the expected strong negative correlation exisots between frequency of contraction and cell size, and 2) that the expected positive correlation exists between volume output of the vacuole and cell size. An additional experiment indicates the improbability of Tucker's hypothesis ('71) that the epiplasmic layer provides a barrier to water flux through the cell cortex.
Stroboscopic illumination for the assessment of hyperactivated montility of mouse spermatozoa
Authors: Cooper T. G. , Woolley D. M.
Published: June 2005

Spermatozoa showing hyperactiveated motility can be recognized in multie‐exposure micrographs. The cells were confined in 10‐μm‐deep chambers, illuminated in darkfield conditions, and photographed using a stroboscope (10 Hz) Hyperactivitation, as judge from the pattern of ten superiemposed images, coul be promoted by raising the ionic strength of the medium but did not occur in the absence of calcium.
Mutants of Caenorhabditis elegans with dumpy and rounded head phenotype
Authors: Hosono Ryuji , Hirahara Katsumi , Kuno Sigeru , Kurihara Takayuki
Published: June 2005

Mutations bearing morphological alterations in both head and body are reported in Caenorhabditis elegans. Although most dumpy mutants so far isolated have shorter bodies with normal head form, the mutants presented in this paper have rounded heads in addition to dumpy bodies. On examination with light‐ and scanning electron microscopes, defects in organs attached to the tip of head were not detected. The mutations were mapped as alleles of the dpy‐20 gene on linkage group IV. Segregation of the head abnormality from dumpy body was not detected upon examination of over 10,000 descendants from heterozygous offspring (F1), produced by crossing mutant hermaphrodites with wild‐type males. Revertants of dpy‐20 (cn142) allele were found to be almost wild‐type in both head and other body morphology, supporting the possibility that both phenotypes in these alleles have been produced by a single mutation. Genetic analyses of two other revertants are also presented in this report.
The leg flexor muscle of Carcinus. II. Distribution of muscle fiber types
Authors: Parsons David W. , Mosse Peter R. I.
Published: June 2005

Three types of muscle fiber were recognized in the leg flexor muscle of Carcinus maenas on the basis of histochemical staining for the oxidative enzyme NADHD and analysis of fiber cross‐sectional area. The distribution of these fiber types within the muscle is described. The oxidative capacity and cross‐sectional area of the fiber was correlated with the fiber type determined physiologically.
Developmental aspects of hexose metabolism in Bufo bufo
Authors: Miranda Michele , Botti Dario , Pantani Claudio , Ragnelli Anna Maria , di Cola Mario
Published: June 2005

Due to the close correlation between glucose mobilization and utilization within animal tissues, in this paper, the stages of appearance of phosphorylase, glucose‐6‐phosphatase and hexokinase as well as the levels of some intermediates of glucose metabolism have been investigated during Bufo bufo development. Phosphorylase first appears at stage 13 and is dominant in the neural part of the embryo, but, after this stage, increases relatively more in the nonneural one. Hexokinase appears at stage 17 and glucose‐6‐phosphatase soon after. Phosphorylase appearance at stage 13 is correlated with an increase of lactate content in the embryo; this may indicate a metabolization of hexoses. On this basis, the subsequent appearance of hexokinase and glucose‐6‐phosphatase activities also seems coherent with hexose mobilization and utilization within embryo. No direct causative factor for the changes observed was evident.
Effect of environmental temperature on the incorporation of 3H‐ethanolamine into the phospholipids of the tissues of the crab Carcinus maenas
Authors: Chapelle S. , Brichon G. , Zwingelstein G.
Published: June 2005

Incorporation of 3H‐ethanolamine in phosphatidylethanolamine (PE) and in phosphatidylcholine (PC) isolated from different tissues of crab Carcinus maenas was analyzed at environmental temperature of 13°C and 23°C. The stepwise N‐methylation of PE to PC occurs only in the hepatopancreas, its importance being greater in animals living at 23°C. The hemolymph‐hepatopancreas exchange of PC plays an important part on the regulation of the hepatopancreas PC pool. Also, the environmental temperature strongly influences PC distribution between hemolymph and hepatopancreas.
Adhesion of osteoclasts and monocytes to developing bone
Authors: Martini Mary C. , Osdoby Philip , Caplan Arnold I.
Published: June 2005

Osteoclast resorption of bone matrix during bone development is preceded by cell attachment to bone. An in vitro assay is described that measures adhesion of isolated osteoclasts and their presumed progenitor cell, the monocyte, to embryonic chick bone. Osteoclasts were isolated from day 19 chick tibia and enriched. Circulating chick hatchling monocytes were purified by Ficollhypaque sedimentation and attachment to plastic. Isolated cells were labeled with (32P)‐KH2PO4 to quantitate cell attachment. In one series of experiments, labeled cells were inoculated into vessels containing day 19 tibias with either endosteal or periosteal bone surface exposed. Labeled cells were also inoculated into chambers containing day 6 (cartilage cores), day 12 (bone and cartilage cores), or day 19 embryonic tibias (bone). Cultures of stage 24 chick limb mesenchyme and embryonic chick skin fibroblasts served as controls. Results demonstrate that twice as many osteoclasts and monocytes adhere to bone as compared to fibroblasts and stage 24 limb mesenchymal cells. Furthermore, there does not appear to be selective adhesion to the endosteal as compared to periosteal bone surfaces. When the data is calculated on the basis of cell attachment per area of each substrate, the day 12 cores had slightly higher number of osteoclasts and monocytes attached compared to day 19 bones; day 6 cartilage cores bound few cells. These observations suggest that osteoclasts and monocytes have a high affinity to bone which seems to be influenced by the developmental age and composition of the substrate.
5‐Hydroxytryptamine causes contraction of smooth muscle cells in preovulatory hamster follicles
Authors: Talbot Prudence , Schroeder Paul C.
Published: June 2005

We have examined the effect of 5‐hydroxytryptamine (5‐HT) on ovaries removed from hamsters and placed in culture 12 or 13 hours after hCG injection. The four responses to 5‐HT which were studied include: (1) contraction of follicular smooth muscle cells (SMC), (2) formation of a V‐shaped constriction in the base of follicles, (3) changes in the profile of follicles, and (4) changes in intrafollicular pressure. Our results show that 10−3 M 5‐HT alters the ultrastructure of follicular SMC to that characteristic of a contracted state. The contraction of these SMCs produces in turn: (1) a V‐shaped constriction in the base of the follicle similar to that observed in unstimulated 13 hour ovaries undergoing in vitro ovulation (Martin and Talbot, '81a), and (2) a change in the profile of the follicle which becomes taller and more spherical, but not identical to the “true” tall follicle seen during normal in vitro ovulation. The fact that 5‐HT does not change the follicle to a “true” tall profile and does not induce immediate ovulation in most cases (even though SMC are contracted) suggests to us that the apices of these follicles were not sufficiently weakened by enzymes to permit immediate rupture when SMC contracted. The response of SMC to 5‐HT was immediate, rapid, sustained at least 10 minutes, and could be inhibited by methysergide. The latter observation suggests that 5‐HT interacts with “D” receptors of SMC and not “M” receptors of nervous tissue. The degree of contraction elicited by 5‐HT varied from one follicle to another; many SMC did not appear maximally contracted by morphological criteria. Intrafollicular pressure increased in most follicles treated with 5‐HT; pressure returned to initial levels relatively quickly, presumably because fluid was able to seep through developing ruptures in the apex. Intrafollicular pressure does not increase during unstimulated in vitro ovulation (Schroeder and Talbot '82). We interpret the intrafollicular pressure data of this study to mean that 5‐HT elicits a much more rapid contraction of SMC than would ordinarily occur in vitro. Thus, SMC contraction in follicles not stimulated by 5‐HT would be a slow, gradual, process allowing constant or decreasing levels of pressure to be maintained. Our observations are important in directly showing that: (1) 5‐HT stimulates contraction of SMCs in hamster follicles, and (2) this contraction produces a V‐shaped constriction in the base of the follicle and a change in the profile of the follicle, and (3) that intrafollicular pressure will increase abruptly upon strong, simultaneous contraction of follicular SMC. These observations provide further support for our earlier statement that SMC function in hamster ovulation (Martin and Talbot,'81a).
Remarkable blood catecholamine levels in forced dived ducks
Authors: Hudson Dennis M. , Jones David R.
Published: June 2005

Levels of circulating epinephrine (E) and nor‐epinephhrine (NE) were measured in duck blood before, during, and after forced dives which were extended close to the limit of underwater endurance. Both E and NE increased by, on occasion, three orders of magnitude. After surfacing, plasma catecholamine levels fell rapidly. The reason for this enormous amine release in forced dived ducks remains a matter of speculation.
Cellular localization of estradiol in the Harderian gland of the female armadillo
Authors: Weaker Frank J. , Villareal Cynthia , Sheridan Peter J.
Published: June 2005

Adult female armadillos were injected with tritiated estradiol. The Harderian gland was removed and processed for autoradiography. Nuclear uptake and retention of the steroid were observed in the duct of the gland, the periductal mucous cells of the mucus‐secreting lobules, and the fibroblasts in the interstitial connective tissue.
β‐Alanine oxidation in the liver of the little skate, Raja erinacea
Authors: Leech Anthony R. , Goldstein Leon
Published: June 2005

The pathway of β‐alanine (BALA) oxidation was examined in the liver of the little skate, Raja erinacea. BALA oxidation in liver slices was reduced by inhibitors of transamination and mitochondrial electron transport. Experiments with liver homogenates indicated that BALA was oxidized by a two step process: (1) transamination of BALA to malonate semialdehyde (MSA) and (2) conversion of MSA to CO2 and acetate. Increases in BALA oxidation during osmotic stress are probably mediated by changes in substrate concentration rather than alterations in enzyme levels.
Penetration of zona‐free hamster eggs by boar sperm treated with the ionophore A23187 and inhibition of penetration by antiplasma membrane antibodies
Authors: Smith Michael , Peterson R. N. , Russell Lonnie D.
Published: June 2005

Uncapacitated boar sperm treated with the divalent cation ionophore A23187 in the presence of calcium bind to and penetrate zone‐free hamster eggs. Penetration by ionophore‐treated sperm is, however, blocked when sperm are pretreated with antisperm plasma membrane Fab. The antibody apparently interferes with the interaction of sperm surface antigens with the egg plasma membrane since the antibodies have no significant effect on the motility of sperm nor on the induction of the acrosome reaction by the ionophore. The assay described herein is useful for studying the role of sperm surface antigens in the penetration and fertilization of eggs.
Levels of cyclic GMP and cyclic AMP in regenerating forelimbs of adult newts following denervation
Authors: McLaughlin Hooley M. G. , Rathbone Michel P. , Liversage Richard A. , McLaughlin Danielle S.
Published: June 2005

The effect of short‐term denervation (0, 12, 24, and 72 hours) on the levels of cyclic 3′5′‐guanosine monophosphate (cGMP) and cyclic 3′5′‐adenosine monophosphate (cAMP) in adult newt (Notophthalmus viridescens) fore limbs at 15, 22, and 35 days of regeneration was investigated. Regenerate blastema and stump cyclic nucleotide levels were compared with those of the contralateral intact forelimb and hindlimb, with levels in the normally regenerating blastema, and with levels measured in the forelimbs of intact, nonoperated animals. Variations in cyclic nucleotide levels occurred according to regeneration stage and tissue type. Changes in level were noted immediately upon denervation and subsequently at other sample times in all regenerate and control series. Parallel fluctuations occurred in regenerate stump and contralateral intact forelimbs. Our results from nonamputated denervated and sham‐denervated animals indicate that short term, denervation‐associated cyclic nu eotide fluctuations cannot be attributed solely to the loss of innervation.
Incorporation of [14C]glucose into the tunic of the ascidian, Ciona intestinalis (linnaeus)
Authors: Robinson William E. , Kustin Kenneth , McLeod Guy C.
Published: June 2005

The tunic of Ciona intestinalis contains tunicin fibers, blood cells, and a mucopolysaccharide ground substance. [14C]Glucose is rapidly taken up by the epidermal cells of the body wall underlying the tunic. Radioactivity is incorporated into the tunic, eventually becoming uniformly distributed throughout this structure during the 21‐day postlabeling period. This labeled material is easily removed by mild acid hydrolysis, a procedure that separates the ground substance and most protein from the tunic. We conclude that the majority of the [14C] glucose is utilized by the epidermal cells in the production of the mucopolysaccharide of the ground substance. Some label remains associated with the tunic residue even after extensive acid hydrolysis, however, indicating that only a small amount of the labeled glucose may be incorporated into the tunicin fibers themselves.
Nocturnal rhabdom cycling and retinal hemocyte functions in crayfish (Procambarus) compound eyes. II. Transmission electron microscopy and acid phosphatase localization
Authors: Waterman Talbot H. , Piekos W. Barry
Published: June 2005

Cytoplasmic synthetic organelles (Golgi complexes, polysomes, and rough and smooth endoplasmic reticulum) are present in most photoreceptor cells of the crayfish retina in winter throughout the late‐night 24:00 to 06:00 h period. These same retinular cells contain few or no lysosome‐like bodies. There is no evidence for autophagic receptor membrane breakdown even during the degradative phase (24:00 to 02:00 h) of the late‐night quadrant.

The fine structure of rhabdom microvillus bases and their continuity with retinular cell somata and endoplasmic reticulum differ characteristically in each of the three successive turnover phases between 24:00 and 06:00 h. Typical stalked attachment of microvillus clusters to retinular cell bodies is resumed by 06:00 h.

A minority of retinulas are severely abnormal. Their rhabdoms are shorter and closer to the basement membrane while their receptor cell nuclei have descended proximally. During the degradative phase, the retinular somata may lack synthetic organelles altogether while their rhabdoms are disorganized, detached from their parent cytoplasm, and occasionally invaded by hemocytes. In contrast, synthetic organelles are numerous in the cytoplasm during the late synthetic phase (03:00 to 04:00 h) when photoreceptor membranes are less disrupted and cytoplasmic bridges between rhabdoms and cell bodies are intact.

Both moderate late‐night degradation of the rhabdom and the less frequent catastrophic breakdown seem to be mediated by extracellular lysozymes provided in part by retinal hemocytes. Acid phosphatase localization at the beginning of the degradative phase (24:00 to 00:30 h) demonstrates that invasive granulocytes are a primary source of this enzyme. Another hemocyte function previously hypothesized is proven here by finding phagocytized fragments of rhabdom and other retinal elements in most of the retinal macrophages during late‐night synthetic and resting phases.
Effects of microphthalmic white (Miwh) on the number and function of cutaneous melanocytes
Authors: Pratt Bruce M.
Published: June 2005

Microphthalmic white (Miwh), when heterozygous, causes dilution of black fur to a uniform gray color. Miwh/+ also reduces the coloration of ear and tail skin. The present study, a quantitative assessment of the effects of Miwh/+ on cutaneous melanocytes, demonstrates that the primary effect of Miwh/+ on cutaneous pigmentation is to reduce the number of epidermal melanocytes. There is also indirect evidence that Miwh/+ reduces the rate of melanosome production within follicular melanocytes. These actions of Miwh/+ cause both lightened coloration of ear and tail skin and the deposition of fewer numbers of smaller melanosomes within the hair.
Distribution of photoreceptors inducing ciliary reversal and swimming acceleration in Blepharisma japonicum
Authors: Matsuoka Tatsuomi
Published: June 2005

The distribution of photoreceptors was examined with respect to those initiating ciliary reversal and those inducing acceleration of swimming. Ciliary reversal was caused when a light stimulus was applied to the anterior end of the animal; the response did not occur when the light was applied to a region within the posterior three‐fifths of the animal. On the other hand, acceleration of swimming was induced by light application to both anterior and posterior fragments. These differences in response suggest that the photoreceptors initiating ciliary reversal are different from those inducing acceleration of swimming.
Morphological and physiological identification of motor neurons innervating flight musculature in the cockroach,Periplaneta americana
Authors: Ritzmann Roy E. , Fourtner C. R. , Pollack Alan J.
Published: June 2005

Morphological and physiological data were used to establish which motor neurons innervate known wing elevator and depressor muscles. Nerves to identified muscles were backfilled to establish the neuropilar morphology of neurons innervating each muscle. Individual motor neurons were recorded intra‐cellularly during flight sequences and then filled. The intracellularly identified cell was then matched with backfilled cells that had similar ganglionic morphology, exited the same nerve root, and had the same function during the flight cycle. In this way the target muscle of five elevator and five depressor motor neurons was established.
Catalytic properties of the sperm‐specific lactate dehydrogenase (LDH X or C4) from different species
Authors: Coronel Carlos E. , Burgos Carlos , Gerez De Burgos Nelia M. , Rovai Leonor E. , Blanco Antonio
Published: June 2005

A comparative study of catalytic properties of the sperm‐specific lactate dehydrogenase (EC 1.1.1.27) isozyme X or C4 from a variety of animals (boar, bull, goat, Guinea pig, man, mouse, pigeon, rabbit, and rat) is presented. Optimum concentration and Km values for pyruvate, inhibition by substrate, and activity against analog substrates (α‐ketoacids with linear and branched chains from 4 to 6 carbon atoms) for isozyme X of different species showed significant differences. The observed properties are correlated with available evidence on the metabolic role of the enzyme.
Thiosemicarbazide‐induced osteolathyrism in metamorphosing Xenopus laevis
Authors: Newman Samuel M. , Dumont James N.
Published: June 2005

Exposure of Xenopus laevis tadpoles to thiosemicarbazide (TSC), at concentrations from 10 to 75 mg/liter, causes an inhibition of metamorphosis and produces the classic manifestations of the experimental disease, osteolathyrism. Concentration‐dependent effects of TSC exposure are observed in growth rate and in the severity of the osteolathyrogenic effect. Concentrations allowing the most rapid growth produce the more extreme osteolathyrogenic defects. Osteolathyrism in these animals is identical in characteristics to the condition described in a wide variety of vertebrate species.

In Xenopus, osteolathyrism is expressed morphologically as anomalies in bone development, skeletal conformation, and abnormal connective tissue organization in the aorta wall. The underlying defect responsible for these observations is apparently a perturbation of collagen fiber formation and maturation, as evidenced ultrastructurally by aberrant distribution and packing of collagen fibers. It is suspected that TSC produces this effect by altering the availability of copper ion, a cofactor to lysyl oxidase, an essential enzyme for intermolecular cross‐linking of procollagen. This step in collagen metabolism has been consistently implicated as the site of action of several osteolathyrogenic agents.

Xenopus tadpoles present a classic response to this known osteolathyrogen and demonstrate a high degree of uniformity of response within the experimental groups. In view of the developmentally significant events accessible with this system and inherent logistic and economical advantages, the metamorphosing tadpole of Xenopus holds considerable potential for the experimental analysis of teratogenic agents and events.
Immunofluorescent localization of a seminal vesicle proteinase inhibitor in the female reproductive tract of naturally inseminated mice
Authors: Nicholson Nanette , Irwin Michael , Poirier Gary R.
Published: June 2005

The indirect immunofluorescent technique was used to localize a low molecular weight, acid‐stable proteinase inhibitor of seminal vesicle origin in the female reproductive tract of mice. In recently inseminated animals (0, 2, and 4 hr postcoitus) the inhibitor was localized in the copulatory plug, on the epithelia of the vaginal fornix and cervix, in the uterine lumen, and on the apical surface of the uterine epithelium. Ten hours postcoitus the inhibitor was found in localized areas on the uterine epithelium, in a sperm‐leucocyte mass in the uterine lumen, and in the copulatory plug. The inhibitor was not found in females 24 hr postcoitus. The inhibitor could not be localized in the oviducts of any of the animals tested. The data are interpreted to mean that the inhibitor, transported to the female at ejaculation, coats the surface of the female reproductive tract protecting it from acrosomal enzymes or from invasion by spermatozoa or pathogens.
Effects of protease inhibitors on early events in the conjugation of Paramecium caudatum
Authors: Kitamura Akio
Published: June 2005

The effects of 11 different protease inhibitors on mating reactivity and pair formation in the conjugation process of the ciliated protozoan Paramecium caudatum were investigated. Of the 11 inhibitors tested, six microbial and three synthetic inhibitors showed no effect on either pair formation or mating reactivity even at their highest concentrations. Soybean trypsin inhibitor and ovomucoid also showed no effect on pair formation even though they temporarily repressed mating reactivity. These results indicate that the process of pair formation during the conjugation process does not involve an extracellular proteolytic reaction.
Reassortment of cells according to position in mouse morulae
Authors: Surani M. Azim H. , Handyside Alan H.
Published: June 2005

Sixteen‐cell mouse morulae were disaggregated and blastomeres originally occupying outer or inner positions were separated. Outer, inner, or unsorted populations of blastomeres were labeled with either trinitrobenzene sulphonic acid (TNP) or fluorescein isothiocyanate (FITC) and individual blastomeres aggregated to unlabelled partially decompact eight‐ to ten‐cell morulae. After up to 6 h in culture, the positions of the labelled blastomeres within the aggregates were examined. The combined results demonstrated that between 86 and 92% of outer cells remained on the surface of the aggregate and flattened into extensive polygonal shapes, whereas 76–77% of the inner cells had become engulfed by the host morula cells and retained their initial spherical shape. Using unsorted cells, 33–37% were internalised, which is compatible with the most recent estimates of the presence of six to eight inner cells at the 16‐cell stage. The possibility that differential adhesiveness of the outer and inner cells is involved in the allocation of cells to the trophectoderm and inner cell mass of the blastocyst is discussed.
Intrafollicular pressure promotes partial evacuation of the antrum during hamster ovulation in vitro
Authors: Talbot Prudence
Published: June 2005

The role of intrafollicular pressure in evacuation of the hamster cumulus from the follicle at ovulation was investigated experimentally in vitro. Previous work has shown that the cumulus is generally evacuated in two stages (Talbot, '82). Phase 1 occurs immediately at rupture and is characterized by rapid (<60 seconds) extrusion of about 20% of the cumulus and usually the oocyte. Phase 2 includes the gradual (2–10 minutes) removal of the remainder of the cumulus and collapse of the follicle wall. Fresh or aged follicles (approximate intrafollicular pressures = 2.1 or 0.0 mmHg, respectively) were poked with “0” gauge insect pins to produce a rupture site in their apices. Of 69 fresh follicles tested, 68 responded with phase 1 extrusion; 57 of the 68 evacuated the oocyte in addition to a significant portion of the cumulus. In contrast, only seven out of 80 aged follicles showed phase 1 extrusion, and only three out of these seven extruded the oocyte. To verify that phase 1 extrusion in fresh follicles was due to intrafollicular pressure and not smooth muscle cell (SMC) contraction, some fresh poked follicles were fixed for microscopy. Twelve of 14 follicles had flat bases or small V‐shaped constriction in their bases, indicating SMC contraction had not occurred. This was further substantiated by examining several follicles with transmission electron microscopy; SMC in the theca externa were relaxed by morphological criteria. To determine if phase 2 extrusion occurred in poked follicles, fresh follicles were poked, cultured in vitro for 3 hours, and examined microscopically. Phase 1 occurred in all follicles after poking. The remainder of the cumulus was eventually evacuated from the antrum, although much more slowly than during normal in vitro ovulation. The follicle wall did not collapse in these trials. We conclude that intrafollicular pressure is responsible for phase 1 extrusion, i.e., rapid passage of part of the cumulus and oocyte through the rupture site, and that intrafollicular pressure will promote phase 1 extrusion in the absence of SMC contraction. The remainder of the cumulus can be evacuated in the absence of IFP and collapse of the follicle wall; perhaps this occurs by hydration of that portion of the cumulus evacuated during phase 1. Hydration would tend to expand the cumulus and pull the remaining cumulus from the antrum. These results establish a role for intrafollicular pressure in hamster ovulation.
Fertilization and cleavage of bovine follicular oocytes in rabbit reproductive tracts after maturation in vitro
Authors: Fukui Yutaka , Fukushima Moriyuki , Ono Hitoshi
Published: June 2005

Bovine follicular oocytes cultured in vitro in Ham's F‐12 based medium for 27 hours were transferred to the oviducts of rabbits pretreated with 75 IU hCG 24 hours previously. Frozen‐thawed bull spermatozoa were inseminated into the uterus of rabbits 0, 2, 4, 6, 9, and 12 hours before oocyte transfer. Fertilization and cleavage were examined in the oocytes recovered from the oviduct and uterus 24 and 48 hours later. The criteria of fertilization were the presence of an enlarged sperm head, sperm tail, and pronuclei in the vitellus. Bull spermatozoa inseminated 4 hours before oocyte transfer showed the highest rates of fertilization at both 24 and 48 hours (35% and 38%) compared to the other preincubation times. The numbers of cleaved oocytes were also greater at these times. The results indicate that the capacitation time of cryopreserved bull spermatozoa in the rabbit reproductive tract is the same as in the bovine tract—i.e., 4–6 hours.
Photoperiodic control of reproduction in a female migratory bunting (Emberiza bruniceps)
Authors: Tewary P. D. , Tripathi B. K.
Published: June 2005

Two series of experiments were performed with photosensitive female redheaded buntings. In the first series, birds were exposed to various cycles (8L/16D, 12L/12D, 13L/11D, 15L/9D, and 20L/4D) for 35 days. In the second, birds were maintained for a period of 120 days under long day lengths (15L/9D), short day lengths (8L/16D), and normal day lengths (NDL). Periodic laparotomies of birds under these schedules indicated that long days induced ovarian growth followed by regression and refractoriness, short days were ineffective, and that the birds in NDL showed ovarian growth during periods in the summer of increasing day lengths, followed by spontaneous regression. Groups of photorefractory birds in long days were transferred to short days (8L/16D) for different periods in order to terminate the refractoriness before returning them to 15L:9D for another 20 days. The results from both series of experiments suggest that the female redheaded bunting uses photoperiods as a primary environmental source of information in regulating its reproductive responses. The threshold for its gonadal activities is a photoperiod of 12–13 h daily. A period of insensitivity (photorefractoriness) develops in buntings that are photostimulated, requiring about 8 weeks of short days for its termination.
Hormone‐independent GVBD induces cytoplasmic maturity in the starfish oocyte
Authors: Guerrier P. , Meijer L. , Moreau M. , Longo F. J.
Published: June 2005

In the absence of hormone (1‐methyl adenine, 1‐Ma) oocytes from three different species of starfish have been induced to undergo cytoplasmic maturation, including polar body extrusion, sperm aster differentiation, and pronuclear development by mechanical disruption of the germinal vesicle. The factors responsible for aster and pronuclear differentiation appear to develop independently of protein synthesis as observed following an incubation in cycloheximide. The effect of the drug diamide suggests, however, that phosphorylation of preexisting proteins might be involved in this process. While 1‐Ma applied to fertilized, enucleated oocyte fragments is only able to induce sperm aster differentiation without male pronuclear development, both processes occur under the influence of nucleoplasm, without previous hormone treatment. These results suggest that substances originating in the germinal vesicle induce cytoplasmic maturation, i.e., the development of polar bodies, sperm asters, and pronuclei, and question whether there is a direct role of the maturation promoting factor in these processes.
Functional capacity of sex‐reversed (XX, Sxr/ +) mouse germ cells as shown by progeny derived from XX, Sxr/ + oocytes of a female chimera
Authors: Bradbury Michael W.
Published: June 2005

Mice of the genotype X/X, Sxr/ + (Sex‐reversed) are sterile phenotypic males. Testis size is reduced and there is a failure of spermatoge‐nesis during meiosis I. A female chimeric mouse has been produced whose germ line is entirely composed of X/X, Sxr/ + germ cells. The progeny of this chimera included several XX, Sxr/ + males. The finding that X/X, Sxr/ + germ cells can produce fully functional oocytes has implications for the function of the Sex‐reversed gene, the control of germ cell differentiation, and the role of germ cells in primary sex determination.
Postlarval changes in the external morphology of dactyl setae in the kelp crab, Pugettia producta (randall)
Authors: Hamilton K. A.
Published: June 2005

Morphological changes, which include growth, encrustation, and abrasion, occur in the sensory setae and nonsensory denticles located on the dactyls of the walking legs during the postlarval development of the kelp crab, Pugettia producta (Randall). The growth of the denticles is isometric (slope ∼ 1), while the growth of the setae is negatively allometric (slope < 1), relative to the growth of the dactyls. The increase in the sizes of the setae, but not of the denticles, appears to slow before growth stops at maturation, when molting ceases. The most striking morphological changes in the setae occur after maturation. While the setae of all but recently molted juvenile crabs are heavily encrusted by epibionts, the dactyls of most mature crabs are clean, and both the setae and denticles are so abraded that only their bases remain. The consequences of these morphological changes are discussed in relation to the sensory capabilities of a long‐lived, nonmolting majid crab.
Oogenesis in Fundulus heteroclitus. III. Vitellogenesis
Authors: Selman Kelly , Wallace Robin A.
Published: June 2005

Several physiological parameters associated with oocyte growth (vitellogenesis) in the killifish, Fundulus heteroclitus, are defined. Hepatocytes from females and estrogen‐treated males are highly synthetic cells, whereas those from males are relatively quiescent. A 200,000‐molecular weight phosphoprotein (vitellogenin) has been identified by sodium dodecyl sulfate (SDS)‐gel electrophoresis in the plasma of females and estrogen‐treated males and isolated chromatographically using a potassium phosphate gradient system on DEAE‐cellulose. To inhibit proteolysis, the nontoxic inhibitor, aprotinin, was injected into fish prior to bleeding. The structure of vitellogenic follicles and the process of oocyte growth are described. Once follicles reach a diameter of 0.5 mm, their oocytes incorporate exogenous materials by micropinocytosis and sequestered material is immediately translocated to yolk spheres in the oocyte cortex. This process has been followed by using the tracer horseradish peroxidase. Exogenous proteins appear to leave the perifollicular capillaries via an intercellular route and pass through intercellular channels within the follicular epithelium and patent pore canals of the vitelline envelope before reaching the oocyte surface. [32P]Vitellogenin isolated from F. heteroclitus, [3H]vitellogenin isolated from X. laevis, and the dye trypan blue have been used to determine which sized follicles are vitellogenic (i.e., incorporate exogenous materials into growing oocytes). Morphological and autora‐diographic studies are presented to confirm that sequestered macromolecules are incorporated into yolk spheres in the growing oocyte. Follicles appear to grow from 0.5 to 1.3 mm in diameter due to vitellogenesis and subsequently undergo an additional increase in size, which is primarily due to hydration, during oocyte maturation (Wallace and Selman, '78).
Influence of the hydric environment on sexual differentiation of turtles
Authors: Gutzke William H. N. , Paukstis Gary L.
Published: June 2005

Phenotypic sex of hatchling painted turtles (Chrysemys picta), a species known to exhibit temperature dependent sex determination, is influenced by the hydric environment to which developing embryos are subjected. Hatchling sex ratios vary significantly over the range of 26.5 to 28.5°C due to effects of the hydric environment.
A comparative study of tentacle regeneration and number in symbiotic and aposymbiotic Hydra viridis: Effect of zoochlorellae
Authors: Rahat Menachem , Reich Vanda
Published: June 2005

The effect of symbiotic zoochlorellae on tentacle number and budding in Swiss and Israeli strains of Hydra viridis in the light and in the dark, in normally grown and in regenerating specimens has been studied. The mean tentacle number in symbiotic and aposymbiotic hydra was 8.65 ± 1.05 and 7.48 ± 0.86 in the Swiss strain, and 8.62 ± 1.29 and 6.66 ± 0.72 in the Israeli strain. In aposymbiotic hydra reinfected with zoochlorellae isolated from either strain, the number of tentacles increased to that of symbiotic hydra. Decapitated symbiotic hydra regenerated more tentacles than aposymbionts, and regenerating Swiss symbionts also formed more buds than their respective aposymbiotic hydra. The algal enhancing effect was found in the light and in the dark. Regeneration rate was initially higher in the symbiotic hydra, and the ratio between the number of tentacles formed by the regenerating symbiotic and aposymbiotic hydra varied daily during the experimental period of 7 days. We conclude that in H. viridis the endosymbiotic zoochlorellae exert a significant stimulatory and morphogenic effect in the light and in the dark. We do not know yet how the algal effect is mediated to their host. We suggest that a distinction should be made between the stimulatory effect on regeneration rate and the morphogenic effect on the final number of tentacles or buds.
Developmental physiology of corpora allata and accessory sex glands in the cecropia silkmoth
Authors: Shirk Paul D. , Bhaskaran Govindan , Röller Herbert
Published: June 2005

The storage of large quantities of juvenile hormone (JH) in adult male Cecropia silkmoths is dependent upon the combined activities of two organs: secretion by the corpora allata (CA) and accumulation by the accessory sex gland (ASG). We describe here some aspects of CA‐ASG development and physiology which lead to JH storage.

The ASG were found to have completed development and had secreted the luminal materials before eclosion. After day 16 of adult development, the ASG were able to convert JH‐I acid to JH‐I and store the JH‐I. When incubated in vitro, the ASG showed a specificity for the uptake and storage of the three JH acids in the following order : JH‐I > JH‐II ≫ JH‐III. The CA of male and female larvae secreted JH‐I and JH‐II when incubated in vitro, whereas adult male CA secreted JH‐I acid and JH‐II acid. The total equivalent synthetic productivity of adult male CA was found to be considerably greater than that of adult female CA. When cultured in vivo during metamorphosis to the adult in hosts of the opposite sex, the male and female CA maintained their respective pattern of secretory activity. Thus, the CA appear to be programmed to express the sexually dimorphic activity prior to the initiation of adult development.
Polyspermy inhibition in the oyster, Crassostrea virginica
Authors: Alliegro Mark C. , Wright David A.
Published: June 2005

Inhibition of polyspermy is a critical response during fertilization which ensures that only one sperm nucleus will fuse with the female pronucleus to restore the diploid state. Oyster (Crassostrea virginica) eggs prevent polyspermy by a process occurring at the cell surface. However, 5 min after fertilization, there are still functional sperm receptor sites available for penetration by supernumerary sperm. Reinsemination experiments indicate that there is no decrease in the number of penetration sites during this interval. Yet, the number of sperm entering eggs is restricted to one per fertilized egg at a sperm:egg ratio of 1000:1. At a sperm:egg ratio of 105:l, an average of only six sperm were able to penetrate each egg. Gamete binding experiments indicate that there is a gradual decrease in the number of sperm bound to eggs starting at approximately 75 sec and continuing until all sperm are detached. Since eggs are fertilized within seconds of insemination and this process takes at least 12 min, it is considered an unlikely mechanism for the polyspermy block. There are no ultrastructural correlates to the polyspermy block nor to the unbinding of sperm, such as secretion of cortical granules or fertilization envelope formation. Based on reinsemination experiments, kinetic data, and ultrastructural observations, we suggest a physiological block to polyspermy which prevents fusion of gamete plasma membranes, and is mediated by an inhibitory effect directly upon the sperm.
Detection of differences in surface carbohydrates of unfertilized and fertilized golden hamster eggs using potato agglutinin
Authors: Oikawa Taneaki , Maruyama Yuko
Published: June 2005

Changes in the surface carbohydrate moieties of zonae pellucidae and naked vitelli isolated from unfertilized and fertilized hamster eggs were examined through potato agglutinin (STA)‐mediated agglutination and binding of FITC‐STA as a marker. The results indicated that the stereochemical properties of the saccharide residues within STA‐binding sites on the outer surface of the zona pellucida, inner region of the zona pellucida, and the surface of the ooplasmic membrane were different in unfertilized and fertilized eggs, that part of the differences between the two kinds of eggs could be visualized with FITC‐STA and that, on the basis of these data, if we use STA as a probe to analyze the surface change following fertilization, we may be able to analyze these changes to a substantial degree.
Ascidian one‐half embryos can develop into functional adult ascidians
Authors: Nakauchi Mitsuaki , Takeshita Toshikazu
Published: June 2005

Although adult ascidians have remarkable regenerative potency, the ascidian egg is considered a typical “mosaic” egg. A single blastomere isolated at the two‐cell stage develops into a half tadpole with minor or major defects, and this rigidity of ascidian development is known to depend on the localization of cytoplasmic determinants. Between the egg and adult, the ascidian larva has a dual nature consisting of differentiated cells for larval activities and undifferentiated cells that later become differentiated and function in the adult. Although ascidian larvae derived from a hemiembryo are deficient, no one has yet investigated the possibility that the adult might have regulative powers not present in the embryo and might be able to form an entire adult ascidian. Using Styela plicata, we have approached this problem. We report here for the first time that ascidian half embryos can form tadpoles that have the potency to hatch, metamorphose, and develop into functional ascidians.
The incorporation of unsaturated fatty acids of the n‐9, n‐6, and n‐3 families into individual phospholipids by isolated hepatocytes of thermally‐acclimated rainbow trout, Salmo gairdneri
Authors: Hazel Jeffrey R.
Published: June 2005

Rates of incorporation of 1‐14C‐oleic (18:1n9), ‐linoleic (18:2n6), and ‐linolenic (18:3n3) acids into individual phosphatides were determined in isolated hepatocytes from cold (5°C)‐ and warm (20°C)‐acclimated rainbow trout, Salmo gairdneri. Fatty acid incorporation into phosphatidylcholine (PC) exceeded that into all other phospholipids, but at assay and acclimation temperatures of 5°C, incorporation into phosphatidylethanolamine (PE) was generally intermediate between that of PC and the remaining phosphatides. Specific radioactivities (ratios of percentage isotope incorporation‐to‐mole percentage of phosphatide) were consistently less than one for both PC and PE, and greater than one for phosphatidic acid (PA), lysophosphatidylcholine (LPC), phosphatidylserine (PS), and cardiolipin (CL). For PS, specific radioactivities were greater in cold‐ than warm‐acclimated trout, and greater at 5°C than 20°C. Rates of oleate incorporation were generally higher, and rates of incorporation of 18:2 and 18:3 lower in cold‐ than warm‐acclimated trout. Most phospholipids demonstrated a clear preference for the incorporation of 18:2 when assayed at 20°C; however, at 5°C the incorporation of 18:2 was reduced and 18:3 was generally the preferred substrate A reduction in assay temperature from 20°C to 5°C also shifted the incorporation of 18:2 away from PC into PS and PA. These data were interpreted to indicate 1) a cold‐induced activation of PS metabolism, possibly resulting in elevated levels of PE; 2) lower rates of general acyl group turnover in animals acclimated to 5°C than 20°C; 3) a specificity to the acclimation response that favors the incorporation at cold temperatures of polyunsaturated fatty acids, but not the parent acids from which they are derived; and 4) the participation of a deacylation‐reacylation cycle in the metabolism of phospholipids, particularly at cold temperatures.
Calcium concretions in the gills of a freshwater mussel serve as a calcium reservoir during periods of hypoxia
Authors: Silverman H. , Steffens W. L. , Dietz T. H.
Published: June 2005

The gill of the freshwater mussel, Ligumia subrostrata, is composed of 25% calcium concretions on a dry weight basis. These concretions are located extracellularly in the connective tissue of the gill. The concretions have a lamellar structure and occur singly, multiply, and in clumps. The concretions are composed primarily of calcium phosphate and an organic matrix. The concretions are more numerous toward the base of the gill and less frequent in the tip of the gill. The average size of the concretions is 2–3 μm. The concretions are not solubilized in animals exposed to prolonged hypoxic conditions. Instead, as calcium increases in the blood under hypoxic conditions the percentage of the gill dry weight attributed to concretion material increases and the calcium content of the concretion material is elevated. The calcium content of the concretions also is inversely correlated with blood pH. This study indicated that the concretion material in the gills was not mobilized under hypoxic conditions, but served as a calcium reservoir during periods in which the animal was liberating calcium from other sites.
The relationship between motility and the FITC‐BSA binding properties of mouse epididymal spermatozoa
Authors: Stanger J. D. , Quinn P.
Published: June 2005

Mouse epididymal spermatozoa exposed to fluorescein isothio‐cyanate‐conjugated bovine serum albumin (FITC‐BSA) immediately following dilution or after a 2‐hour incubation period under fertilization conditions, were assessed by fluorescence microscopy for albumin adsorption. Motile spermatozoa exhibited light fluorescence in the midpiece and tail but not in the head. In contrast the majority of nonmotile spermatozoa displayed a strong and characteristic fluorescence in the post acrosomal region of the sperm head as well as the midpiece. Spermatozoa immobilised by short‐term heat stress exhibited fluorescence in the post acrosomal region and midpiece as before but also in the acrosomal cap. The equatorial region failed to fluoresce. The significance of these observations on the involvement of albumin in capacitation is discussed.