Ultrastructural and histochemical observations regarding the ovarian follicles of the amago salmon (Oncorhynchus rhodurus)

Pre- and postovulatory ovarian follicles of the amago salmon were investigated with special consideration given to the steroid production site. In the preovulatory specimens, the special thecal cells contained abundant mitochondria and smooth endoplasmic reticulum, as in the case of other steroid-producing cells, while the granulosa cells developed rough endoplasmic reticulum like protein-secreting cells. Remarkably ultrastructural changes occurred in the granulosa and the special thecal cells during the oocyte maturation stage; dilation of rough endoplasmic reticulum in the former cell and further development of smooth endoplasmic reticulum in the latter one. Histochemical reactions of delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity were only positive in the special thecal cells of the postovulatory follicles. These results strongly suggest that the special thecal cells are the major sites of estrogen precursor synthesis in the amago salmon ovary.

In vitro estradiol-17 beta and testosterone production by ovarian follicles of the goldfish, Carassius auratus

In vitro production of estradiol-17 beta and testosterone by ovarian follicles of goldfish (Carassius auratus) at different developmental stages in response to human chorionic gonadotropin (HCG) was examined using 18-hr incubations. The vitellogenic follicles (primary and secondary yolk stage) produced estradiol-17 beta in response to HCG; follicles at the secondary yolk stage produced about five times more estradiol-17 beta than the primary yolk stage follicles. However, tertiary yolk stage follicles, which could be induced to mature in vitro by HCG treatment, did not produce estradiol-17 beta. HCG also stimulated testosterone production by follicles at all stages of development; maximal production was observed in tertiary yolk stage follicles. An indirect assessment of aromatase activity at each stage was made. Vitellogenic follicles (primary and secondary yolk stage) produced estradiol-17 beta when incubated with testosterone, the larger follicles producing about three times more estradiol-17 beta. Only low levels of estradiol-17 beta were produced by tertiary yolk stage follicles. Addition of HCG to primary yolk stage follicles slightly but significantly enhanced estradiol-17 beta production; however, no enhancement was seen with secondary and tertiary stage follicles. These results suggest that the decrease in estradiol-17 beta production in tertiary yolk stage follicles may be partly due to a decrease of aromatase activity at this stage.

Synthesis of flagellin and hook subunit protein in flagellar mutants of Escherichia coli K12

We have examined Escherichia coli K12 flagellar mutants affected in each of 29 different loci for the synthesis of flagellin and hook subunit protein. Immune precipitation experiments were employed by treating cell extracts with antiserum against each protein. Flagellin was synthesized in mutants defective in genes flaS , flaT, flaU and flbC . The flaE and flaZ mutants produced small amounts of flagellin, while all the other mutants failed to produce any detectable amount of flagellin. Hook subunit protein was found in most mutants including those defective in genes flaA , flaB , flaC, flaD , flaE , flaG , flaH , flaL , flaM , flaN , flaO , flaP, flaQ , flaR , flaS , flaT, flaU , flaV , flaW , flaX, flaY , flaZ , flbA , flbC , flbD , and hag but not in mutants of flaK , flaI , and flbB . The results conform to the predictions made by our previous indirect gene fusion study ( Komeda 1982).

Bacteriophage chi sensitivity and motility of Escherichia coli K-12 and Salmonella typhimurium Fla- mutants possessing the hook structure

The production of hook protein and flagellin in 29 Fla- mutants of Escherichia coli K-12 was determined by the complement fixation assay. Six mutants produced hook protein, and four of them also produced flagellin. A flaE mutation was introduced into these fla mutants carrying the hook structure. All of these mutants made polyhooks and were used as hosts for a newly isolated host-range mutant of chi phage that has a high affinity for the hook structure. All except one mutant produced significant amounts of progeny phages. A flaD flaE double mutant was that exception which did not yield significant amounts of progeny by the phage propagation method. All of the flaE double mutants produced comparable amounts of polyhooks, and no qualitative difference was detected between chi-sensitive and chi-insensitive mutants by the complement fixation assay. Accordingly, it was thought that the polyhook of the flaD flaE mutant had a mechanical defect for chi phage infection. This assumption was confirmed by tethered-cell experiments; the flaD flaE mutant did not rotate. These results are well explained by a proposed regulation pathway of flagellar genes. flaE mutants can express other genes which govern the final step of the flagellar morphogenesis, whereas flaD mutants cannot rotate, possibly because the mocha operon is not expressed. The results obtained in E. coli were also found to be applicable to Salmonella typhimurium.

Relationship between seasonal plasma estradiol-17 beta and testosterone levels and in vitro production by ovarian follicles of amago salmon (Oncorhynchus rhodurus)

Plasma estradiol-17 beta and testosterone levels were assessed by radioimmunoassay during the sexual maturation of female amago salmon (Oncorhynchus rhodurus). Estradiol-17 beta levels gradually increased during vitellogenesis (June to September), reached a peak in September (about 16 ng/ml) and rapidly decreased in mature and ovulated fish (about 3-4 ng/ml) in October. The seasonal pattern of plasma testosterone levels lagged behind and followed that of estradiol-17 beta during vitellogenesis, but levels remained high in mature and ovulated fish (90-110 ng/ml). Estradiol-17 beta levels and the gonadosomatic index (GSI) values correlated well during vitellogenesis: GSI values showed a linear increase, and reached a peak (29.9 +/- 1.4) in October. Values were extremely low in ovulated fish (1.2 +/- 0.2). In vitro production of estradiol-17 beta and testosterone by ovarian follicles in response to partially purified chinook salmon gonadotropin (SG-G100) was examined monthly using 18-h incubations. Throughout the vitellogenic period SG-G100 stimulated both estradiol-17 beta and testosterone production: the steroidogenic response of follicles increased from June (about 2 ng/ml estradiol-17 beta; 0.1 ng/ml testosterone) to September (about 10 and 14 ng/ml, respectively). In October full-grown immature follicles which could be induced to mature in vitro by hormone treatment produced large amounts of testosterone (about 130 ng/ml) but not estradiol-17 beta. Postovulatory follicles also produced testosterone but the values were low (10 ng/ml) compared with full-grown immature follicles. Very low levels of estradiol-17 beta were produced by postovulatory follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a decrease in aromatase activity in the ovarian granulosa cells of amago salmon (Oncorhynchus rhodurus) associated with final oocyte maturation

Aromatase activity in the isolated granulosa layers of amago salmon (Oncorhynchus rhodurus) ovarian follicles was examined during the course of vitellogenesis and final oocyte maturation and ovulation. Estradiol-17 beta production by isolated granulosa layers incubated with exogenous testosterone increased during the period of vitellogenesis to reach a peak in late vitellogenesis, and then declined rapidly, in association with the ability of the oocyte to mature in response to partially purified salmon gonadotropin (SG-G100). Extremely low levels of estradiol-17 beta were produced by granulosa layers from follicles which had undergone final oocyte maturation in vivo and by post-ovulatory follicles. SG-G100 had no discernible effect on estradiol-17 beta production. These results are discussed in relation to other studies on the endocrine control of steroidogenesis in this species.

Plasma 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one levels during sexual maturation of amago salmon (Oncorhynchus rhodurus): correlation with plasma gonadotropin and in vitro production by ovarian follicles

Plasma gonadotropin (GtH) and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-diOH-prog) levels were assessed by radioimmunoassay during the sexual maturation of female amago salmon (Oncorhynchus rhodurus). Both GtH and 17 alpha, 20 beta-diOHprog levels were low in vitellogenic females (June to September) and in those with full-grown immature oocytes and were elevated in mature and ovulated females to 40 ng/ml for GtH and 50-70 ng/ml for 17 alpha, 20 beta-diOHprog. In vitro production of 17 alpha, 20 beta-diOHprog by ovarian follicles and its stimulation by partially purified chinook salmon gonadotropin (SG-G100) was examined monthly using 18 hr incubations. In June and July, levels were too low to detect (less than 30 pg/ml) in media from all treatment groups. In August and September, SG-G100 at a concentration of 1 microgram/ml stimulated low levels of production (0.2-0.3 ng/ml). Full-grown, immature follicles in October showed a dose-response production of 17 alpha, 20 beta-diOHprog, averaging over 10 ng/ml when incubated with 1 microgram/ml SG-G100. Postovulatory follicles (1-2 days after ovulation) produced large amounts of 17 alpha, 20 beta-diOHprog, averaging over 100 ng/ml with 1 microgram/ml SG-G100. These results are discussed in relation to previous work on amago salmon and other species and together indicate that 17 alpha, 20 beta-diOHprog is the major steroid responsible for oocyte maturation in amago salmon, produced as the follicular mediator of gonadotropin.

Motility development of Salmonella typhimurium cells with flaV mutations after addition of exogenous flagellin

Cells of Salmonella typhimurium with flaV mutations developed motility after exogenous addition of flagellin, similar to what is observed with flbC mutants of Escherichia coli K-12.

Isolation and characterization of nucleic-acid-like polymers containing glucose from Ehrlich ascites tumor cells

1. Novel nucleic-acid-like polymers containing glucose, glucose 'nucleic acid', were isolated from cytoplasmic particles of Ehrlich ascites tumor cells. It is assumed that the basic structure of the polymers is similar to those of known nucleic acids except that their sugar constituents are glucose derivatives instead of ribose or deoxyribose. 2. When the glucose 'nucleic acid' was incubated with venom phosphodiesterase, four kinds of glucose 'nucleotides' containing bases of cytosine, adenine, guanine and thymine were obtained. 3. When the polymers were incubated with both venom phosphodiesterase and alkaline phosphatase, inorganic phosphates of glucose 'nucleotides' were removed and each nucleotide was converted to a glucose 'nucleoside'.

Oocyte maturation in the amago salmon (Oncorhynchus rhodurus): in vitro effects of salmon gonadotropin, steroids, and cyanoketone (an inhibitor of 3 beta-hydroxy-delta 5-steroid dehydrogenase)

The effect of partially purified chinook salmon gonadotropin (SG-G100) and a number of steroids on the induction of germinal vesicle breakdown (GVBD) in amago salmon (Oncorhynchus rhodurus) oocytes (with intact follicle layers) was investigated in vitro. SG-G100 was effective only at the highest concentration tested (1 microgram/ml). 17 alpha,20 beta-Dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) was the most potent maturation-inducing steroid tested, followed by 17 alpha-hydroxyprogesterone. Testosterone or deoxycorticosterone (DOC) enhanced the rate of GVBD in response to SG-G100. DOC also enhanced the response to 17 alpha,20 beta-diOHprog but testosterone was without effect, suggesting that DOC has a direct action on the oocyte while testosterone probably acts at the level of the follicle. Estradiol-17 beta had no effect on GVBD in response to SG-G100 or 17 alpha,20 beta-diOHprog. The action of SG-G100 was shown to be dependent on the synthesis of a second delta 4 steroidal mediator of maturation since cyanoketone, a specific inhibitor of 3 beta-hydroxy-delta 5-steroid dehydrogenase, completely abolished the maturational effects of the gonadotropin and pregnenolone but not delta 4 steroids. Radioimmunoassay of media in which oocytes were induced to mature in vitro with SG-G100 revealed significantly elevated levels of progesterone and 17 alpha,20 beta-diOHprog. Estradiol-17 beta levels, high in control media, were only elevated twofold by SG-G100. Levels of the two progestogens were extremely low or nondetectable in media in which oocytes were incubated with cyanoketone, while estradiol-17 beta levels remained high. These results are discussed in relation to other evidence indicating that 17 alpha,20 beta-diOHprog is the naturally occurring maturation-inducing steroid of amago salmon. The role of other steroid hormones, particularly the possible involvement of corticosteroids, in the control of final oocyte maturation in teleosts is explored.

In vitro steroid production in the postovulatory follicles of the amago salmon, Oncorhynchus rhodurus, in response to salmon gonadotropin

Partially purified chinook salmon gonadotropin (SG-G100) was used to investigate estradiol-17 beta and progesterone production in vitro in the isolated postovulatory follicles of the amago salmon, Oncorhynchus rhodurus, at varying intervals after ovulation. Chinook salmon gonadotropin stimulated progesterone production in vitro in the young postovulatory follicles, but not in the older ones. In contrast, estradiol-17 beta production was not stimulated in either young or older postovulatory follicles. Morphological observations indicate that young postovulatory follicles are more glandular than older ones. Thus, it is concluded that the young postovulatory follicles of the amago salmon are steroidogenic.

Correlation of plasma estradiol-17 beta and progesterone levels with ultrastructure and histochemistry of ovarian follicles in the white-spotted char, Salvelinus leucomaenis

Plasma estradiol-17 beta and progesterone profiles were correlated with morphological changes in ovarian follicles during the preovulatory and postovulatory periods in the white-spotted char, Salvelinus leucomaenis, Plasma estradiol levels were highest in September, and were followed by a sharp drop in October; they remained very low throughout the postovulatory period. There was a good correlation between plasma estradiol levels and the gonadosomatic index, thus suggesting that estradiol is responsible for the synthesis of vitellogenic proteins. Plasma progesterone levels were very low in August, began to rise in September and reached a peak soon after ovulation; progesterone remained high for several days after ovulation. A preovulatory rise in plasma progesterone levels was recorded, and this is discussed in relation to the induction of oocyte maturation. In the preovulatory follicles, neither granulosa cells nor special thecal cells (ST cells) showed delta 5, 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity. In the young postovulatory follicles, in contrast, the ST cells showed intense 3 beta-HSD activity with extensive agranular endoplasmic reticulum and numerous large mitochondria, while granulosa cells did not show 3 beta-HSD activity. These results strongly suggest that the ST cells are the major sites of progesterone synthesis during the postovulatory period.

Ultrastructural localization of delta 5-3 beta-hydroxysteroid dehydrogenase in the interrenal cells of the goldfisch (Carassius auratus)

The ultrastructural localization of the enzyme delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) was studied in the goldfish interrenal cells by using the potassium ferricyanide method. Immersion fixation in a mixture of 1% paraformaldehyde and 0.25% glutaraldehyde results in a consistently good ultrastructural preservation and enzyme localization. A precipitate of copper ferrocyanide indicating the localization of 3 beta-HSD activity was observed in close vicinity to the smooth endoplasmic reticulum or in contact with the outer surface of its membrane. A small number of precipitated grains were also found in the lumen of mitochondrial cristae. Addition of phenazine methosulfate increased the intensity of the reaction without changing the localization of the copper ferrocyanide grains. The findings suggest that the outer surface of the smooth endoplasmic reticulum is the major site of 3 beta-HSD activity in goldfish interrenal cells.

In vitro polymerization of polyhook protein from Salmonella SJW880

Polyhooks were isolated from Salmonella SJW880, a non-flagellated mutant, and purified by cesium chloride density gradient centrifugation. The polyhooks were disintegrated into protein subunits (monomer) by heat in the absence of salt. The monomer was repolymerized in the presence of moderately high concentrations of sodium citrate at neutral pH. Three types of polymer were produced. One type of polymer, produced at room temperature and at citrate concentrations less than 0.3 M, had no regular shape and no definite thickness. Another type of polymer, produced at room temperature and at citrate concentrations greater than 0.4 M, had a straight shape and a similar thickness to that of polyhook but was easily dissociated into monomer in the absence of salt. A third type of polymer was produced at low temperature, independently of the concentration of citrate, and seemed to be a tubular polymer with a thickness similar to that of polyhook but had no helical curvature. However, this type of polymer was shown to have a structure locally the same as that of polyhook by electron microscopic observation, optical diffraction and circular dichroism measurements.

Diffusion of H-meromyosin in F-actin plus ATP solution at a very low electrolyte concentration

The translational diffusion coefficient (D) of H-meromyosin in actin (F-actin) and ATP solution was measured under conditions wherein the actin-activated ATPase activity is close to its maximal value at a very low electrolyte concentration. The results were compared with similar data obtained with 0.1 M KCl, where H-meromyosin and actin were almost completely dissociated. With 0.1 M KCl, it was found that there was no dependence of the D of H-meromyosin on actin concentration. On the other hand, at a very low electrolyte concentration, it was found that the D of H-meromyosin did depend on actin concentration; at a rather high actin concentration (and activation of ATPase), it was slightly larger than at low or zero actin concentrations. This behavior of D at a low electrolyte concentration is interpreted on the assumption that even in solution, H-meromyosin molecules can actively slide on actin filaments due to the ATPase activity.

Isolation and characterization of bacterial flagellar hook proteins from salmonellae and Escherichia coli

Flagellar hook proteins from Salmonella and Escherichia coli were dissociated in acid and purified by diethylamino-ethyl-cellulose column chromatography. These two proteins had the same electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels. However, analytical electrofocusing patterns showed that these proteins had different isoelectric points (4.7 for Salmonella typhimurium and 4.4 for E. coli). Immunodiffusion and immuno-electron microscopy carried out with antisera prepared against purified hook proteins from S. typhimurium and E. coli showed that these antisera reacted with both hooks. Affinity chromatography allowed separation of antibodies specific for hook proteins from each bacterial species. These results indicate that the hook proteins share common antigenic determinants as well as specific antigens, although the specificity is not quantitatively resolved. From comparisons of the amino acid composition of the hook proteins and flagellins, it was concluded that the differences between flagellins from S. typhimurium and E. coli were larger than those between hook proteins from these species.

Local migration of myosin in F-actin plus ATP solution on the boundary of a diffusion cell

The diffusion phenomena of myosin (myosin A, H-meromyosin or subfragment-1) in F-actin plus ATP solutions were investigated. The upper part of the diffusion cell was filled with F-actin plus ATP, and the lower part was filled with F-actin, ATP, and myosin, then both parts were brought into contact so that a boundary of the two solutions was formed and the diffusion of myosin in F-actin plus ATP solutions started. The diffusion pattern was observed with a schlieren lens system. When almost all the ATP in the lower part of the cell had been consumed by actomyosin, a hyper-sharp schlieren pattern appeared near the boundary. On analyzing this pattern, it was found that a local fast migration of proteins was occurring. Simple Brownian motion of myosin molecules could not explain the hyper-sharp phenomenon. This phenomenon occurred in ther pesence of Mg2+ or Ca2+, but very little in the presence of EDTA. Although it is well known that the superprecipitation of myosin B suspension occurs only at physiological ionic strength, this phenomenon occurred over a relatively wide range of ionic strengths. The molecular mechanism of this phenomenon is discussed in relation to the basic mechanism of the interaction between myosin and F-actin.

Flagellar hook protein from Salmonella SJ25

From acid-disintegrated flagellar hooks of Salmonella SJ25 an immunochemically pure preparation of hook protein was obtained by column chromatography. The molecular weight of the protein determined by sodium dodecyl sulfate-gel electrophoresis was 43,000, whereas that of SJ25 flagellin was 56,000. The amino-terminal residue of the hook protein was determined to be seryl. The amino acid composition of the protein was determined, the results being very similar to that for an Escheria coli hook protein reported by Silverman and Simon (1972). Within a wavelength range of 200 to 250 nm, our purified preparation of hook protein gave a circular dichroism spectrum with unusually small amplitudes, suggesting that the alpha-helix content of the protein was very low.

Change in the ultraviolet absorption of an adenosine triphosphate analog, beta-napht-yl triphosphate, during its hydrolysis by heavy meromyosin

It was found that the absorption spectrum of beta-naphthyl triphosphate is different from that of beta-naphthyl diphosphate in the range 290-335 nm. Thus, beta-naphthyl triphosphate hydrolysis by heavy meromyosin can be recorded continuously as a function of time by means of a spectrophotometer. By analyzing the time course, the apparent kinetic parameters were easily and rapidly obtained. If necessary, the true kinetic parameters, including the product dissociation constants, can be estimated spectrophotometrically. Beta-Naphthyl triphosphate hydrolysis was inhibited competitively by ATP. By analyzing the time course, it was, therefore, possible to estimate the kinetic parameters of ATP hydrolysis indirectly, and resonable values were obtained. Beta-Naphthyl triphosphate hydrolysis by heavy meromyosin was performed under various conditions. Unlike that of ATP, the hydrolysis of beta-naphthyl triphosphate was inhibited monotonously by treatment of heavy meromyosin with p-hydroxymercuribenzoate.

Serological study of bacterial flagellar hooks

Bacterial hooks were partially purified from flagella isolated from Salmonella SJ25, by treatment with heat to depolymerize flagellar filaments and with n-butanol and calcium chloride to remove membranes. Antihook serum was obtained from a rabbit inoculated with a preparation of hooks. The serum contained antibodies directed against the flagellar filament and cell membrane. These antibodies could be removed from the serum by absorption with purified flagellar filaments and cells of a nonflagellated mutant strain. It was shown by electron microscopy that anti-SJ25-hook antibody reacts with hooks from a number of strains of Salmonella which differed from SJ25 in H and O antigens, flagellar shape, and motility. Hooks possessed by various strains of Salmonella have a common antigenicity. In addition, anti-SJ25-hook cross-reacted with hooks from Escherichia coli W3110 but did not react at all which those from strains of Serratia, Proteus, Aerobacter, and Klebsiella. It is well known that bacteria stop moving upon addition of antiflagella serum to the medium. However, the addition of purified antihook was found to have little effect on motility. At physiological ionic strength and pH, flagellin (Salmonella) can polymerize into flagellar filaments only in the presence of seeds. It was shown that a crude preparation of hooks was able to initiate in vitro polymerization of flagellin.