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PubMed1999

Isolation and identification of terpenoid sex pheromone components from extracts of hemolymph of males of the Caribbean fruit fly.

Extracts obtained from hemolymph of sexually mature males of the Caribbean fruit fly Anastrepha suspensa contained four biologically important terpenoid components of the sex pheromone. The four components were identified as farnesene, bisabolene, anastrephin, and epianastrepin based on their relative retention indexes from capillary gas chromatography analysis, using both apolar and polar phase columns and their chemical ionization (isobutane) mass spectra. The ratio of the components in extracts of hemolymph was the same as the ratio present in the volatile blend of pheromone released by sexually mature males during the reproductive period. Studies conducted to determine the effect of age on amounts of these components in hemolymph indicated that they increased from undetectable levels on the day of adult emergence to maximum levels on day eight. The increases in amounts of the components present in hemolymph with increasing age were correlated with increases in amounts of volatile pheromone released by males. Time of day studies showed that the amounts of these components in hemolymph followed the daily pattern of release of volatile pheromone components. Other components of the sex pheromone including ocimene, (Z)-3-nonen-1-ol, (Z,Z)-3,6-nonadien-1-ol and suspensolide were not found in extracts of hemolymph. The data suggest that the hemolymph plays a role in the transport of these pheromone components during sexual signalling. Arch. Insect Biochem. Physiol. 42:225-232, 1999. Published 1999 Wiley-Liss, Inc.

Age Factors↗

PubMed1995

Genetic epidemiology of familial amyloidotic polyneuropathy (FAP)-type I in Póvoa do Varzim and Vila do Conde (north of Portugal).

Familial amyloidotic polyneuropathy (FAP-type I) was first described in Portugal by Andrade in 1952, a time when 54 among 64 patients (belonging to 25 families) originated from Póvoa do Varzim or its surrounding districts. Since then, a total of 1,233 patients, belonging to 489 pedigrees (so far unrelated), have been diagnosed at Centro de Estudos de Paramiloidose, Porto, Portugal. Although age-of-onset showed a wide range (17 to 78 years), 87% of these 1,233 patients developed symptoms before 40 years of age (mean 33.5, SD 9.4 years). Among all patients, 432 belong to 140 families originating from the area of Póvoa do Varzim/Vila do Conde, 330 of whom lived in that area at the time of diagnosis; age-of-onset was, on average, lower than in the overall group of patients (mean 31.1, SD 6.7 years), and no patient had onset after 57 years (versus 3.3% in the global sample). As in previous studies, women were found to have a later onset (33.7) than men (29.0) years. In 1991, the crude prevalence rate was 90.3 x 10(-5) (one in every 1,108 inhabitants), and the frequency of gene carriers was estimated to be 186 x 10(-5) (one in every 538); about 48.4% of these carriers had manifested symptoms by 1991. Female patients had a significantly higher number of children (mean 3.7, SD 2.6) than male patients (mean 2.7, SD 2.1) and the length of their reproductive period (mean 8.4, SD 5.8 yr) was also greater than for men (mean 5.6, SD 4.4 yr). Altogether, the 122 patients who ever reproduced contributed 457 children to the next generation, a mean fertility of 3.7. Further studies using a control groups may answer the question of whether this is the result of a specific high fertility of these patients or just their belonging to a population in natural expansion.

Adult↗

PubMed1994

Does cancer kill the individual and save the species?

I have argued that most germline mutations are due to endogenous process. I speculate that endogenous control of germline mutation serves an important biological function. A certain rate of mutation is required to generate sufficient variation for adaptation during evolutionary time. Sexual reproduction and recombination may serve to enhance variation, but ultimately new germline mutation is required to replenish variant alleles lost secondary to negative selection, genetic drift, and population bottlenecks. Unfortunately, the requisite mutation rates carry a terrible price: for each advantageous mutation, there are many disadvantageous ones. Thus, all mammals are plagued with substantial Mendelian and multifactorial disease. Consequently, the optimal mutation rate should be at a level just sufficient to maintain the requisite variation needed for adaptation. In this view, mechanisms for negative selection are necessary to keep the mutation rate in check. If a high germline mutation rate produces a high mutation rate in somatic tissues, cancer may be an important mediator of negative selection. The multiple mutations necessary to produce cancer serve to amplify relatively small differences in the mutation rate, thereby providing an efficient selection against individuals with germline mutations that result in a high mutation rate. This hypothesis can account for the general similarity of the longevity-corrected cancer incidence profile and the small but significant prevalence of cancer before and during the reproductive period. While this hypothesis must presently be viewed as speculative, it integrates certain previously disjointed observations and suggests an alternative to the general assumption that cancer represents a breakdown in normal physiology.

Animals↗

PubMed1976

A reversible, hydrogen ion blockade of spontaneous oocyte maturation in the starfish: locus of action.

Starfish (Asterias forbesi) oocytes encased within their follicle cells mature spontaneously during a portion of the normal reproductive period when released from the ovary into seawater. A previous report has shown that oocytes isolated in acidic seawater do not mature spontaneously but retain the capacity to do so when returned to normal seawater. The object of this study was to determine the mechanism by which acidic pH reversibly blocks spontaneous oocyte maturation in isolated follicles. Incidence of spontaneous oocyte maturation in follicles isolated in acidic seawater decreased as pH decreased from 7 to 4. Oocytes in which spontaneous maturation was inhibited (ASW at pH 4.7 TO 5.4) underwent germinal vesicle breakdown with the addition of 1-methyladenine. Oocytes isolated in acidic seawater (pH 4 or 5) with intact follicle cells matured spontaneously when transferred immediately to normal seawater pH 8); after four hours, 60-65% of the follicles incubated in seawater at pH 5 matured spontaneously when returned to normal seawater as compared to less than 10% of the follicles maintained at pH 4. Inhibition of spontaneous maturation was not reversible in the absence of the follicle cells. Oocytes isolated in acidic seawater with their follicle cells did not spontaneously mature when transferred to calcium-free seawater at pH 8. The results obtained support the hypothesis that acidic seawater reversibly inhibits spontaneous oocyte maturation by interfering with the release of meiosis-inducing substance from the follicle cells.

Animals↗

PubMed1995

Intratesticular retention of sperm and premature decline in fertility in the domestic rooster, Gallus domesticus.

In domestic roosters, which were originally seasonal breeders and that are now kept under unnatural and unchanging conditions throughout the year, fertility peaks at 32 weeks of age (96%) but it subsequently declines rapidly to only 5% at 110 weeks despite the fact that roosters can live for about 10 years. Roosters exhibiting this low-fertility syndrome have reduced levels of spermatozoa in the ejaculate. Concomitantly, however, superabundant but apparently normal spermatozoa are found attached to Sertoli cells and, in addition, the seminiferous epithelium fails to show evidence of the regression of atrophy that characterizes both aging non-seasonal breeders and true seasonal breeders during non-reproductive periods. This syndrome of premature low fertility appears to stem from impaired spermiation with resultant retention of spermatozoa by Sertoli cells. To examine this problem, we compared intratesticular incorporation of 3H-thymidine between high-fertility (32-week-old) and low-fertility (82-week-old) roosters. Radioactivity associated with spermatozoa, 33 days post-injection, was almost 50% higher in the low-fertility roosters than in the high-fertility ones. By contrast, both groups showed similar characteristics with respect to a) intratesticular incorporation of 3H-thymidine, b) dynamics of spermatogenesis, c) intratesticular level of radioactivity just before the initiation of spermiation, and d) the duration of both spermatogenesis and the time required for sperm to pass through the genital tract. Our results confirm that intratesticular retention of sperm occurs in roosters with premature low-fertility syndrome and suggest new possibilities for the study of the complex relationship between Sertoli cells and spermatozoa and the effects of this relationship on fertility.

Animals↗

PubMed2005

Calcium currents correlate with oocyte maturation during the reproductive cycle in Octopus vulgaris.

Using the whole-cell voltage clamp technique, we have studied the Ca2+ currents and the steady-state conductance during different oocyte growth stages and during the reproductive cycle of the female of Octopus vulgaris. Evidence is presented that L-type Ca2+ currents are high in small pre-vitellogenic oocytes (80-150 microm diameter) and significantly lower in early vitellogenic oocytes (180-300 microm diameter). Similarly, a significant decrease of the steady-state conductance occurred from the pre to early- vitellogenic oocytes. Octopus oocytes showed larger Ca2+ currents in the reproductive rather than non-reproductive periods. These data indicates that ion and L-type Ca2+ currents play a role in oocyte growth and cytoplasmic maturation, and possibly in preparing the plasma membrane to the interaction with the spermatozoon. By using fluorescent microscopy, we show that oocytes from 80 to 400 microm diameter have the large germinal vesicle characteristic of the immature oocytes. In subsequent stages of growth (up to 1000 microm diameter) the nucleus is no more visible and the metaphase spindle appears. These data demonstrate that Octopus vulgaris oocytes are arrested in the first meiotic prophase up to the early-vitellogenic stage and resume meiosis at this stage up to a second block presumably in metaphase I. We discuss a possible role for progesterone as the hormonal stimulus for the first prophase-metaphase meiotic transition.

Animals↗

PubMed1990

Expression of the insulin-like and platelet-derived growth factor genes in human uterine tissues.

The human uterus repeatedly exhibits cyclic biochemical and cytological changes during the reproductive period of life. These changes are the result of a well-characterized endocrine network involving the hypothalamus, pituitary, and ovary. The exact nature of the mechanism(s) by which the sex steroids act on the uterus remains to be elucidated. Possible local mediators of hormonal action on the uterus include polypeptide growth factors. Using the method of RNA transfer blot hybridization, we have analyzed tissue samples from the cycling human endometrium and tissue samples of human myometrium and myometrial benign tumor (leiomyoma) for the presence of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF) RNA. All the uterine tissues examined possessed RNA for PDGF-B chain and IGF-I and -II. Two transcripts were observed for PDGF-B chain, four were observed for IGF-I, and eight were observed for IGF-II. Overall, the relative abundance of PDGF-B chain RNA was consistent in all of the uterine tissues examined. In contrast, IGF RNA relative abundance varied. IGF-I RNA was highest in late proliferative stage endometrium, and IGF-II RNA was highest in early proliferative stage endometrium. Both IGF-I and IGF-II RNAs were greater in amount of leiomyoma than in myometrium. The increased IGF-I RNA in late proliferative-stage human endometrium correlates with the known elevation of estradiol secretion by the ovary and the increased concentration of uterine estradiol receptors during this stage of the menstrual cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Endometrium↗

PubMed1991

Ultrastructural study of the mature egg of the marine sponge Stelletta grubii (Porifera Demospongiae).

Stelletta grubii is an oviparous demosponge, which, during its reproductive period from summer to autumn, has small eggs (80-90 microns) dispersed uniformly in the mesohyl. The nucleolated nucleus is surrounded by dictyosomes containing small vesicles, which contribute to form reserve material. Vesicles, numerous food vacuoles, and groups of mitochondria are observed in the granular cytoplasm. Electron-dense yolk inclusions and lipids are found peripherally. The cortical portion of the egg cytoplasm possesses vacuoles with fibrillar contents. The egg forms pseudopodia, which could permit the capture of numerous bacteria present in the surrounding mesohyl. A thick layer of collagen fibrils, including lophocytes, separates the egg from the surrounding sponge mesohyl. Ultrastructural analysis has demonstrated the presence both of cellular components capable of autosynthetic activity (nutrient vesicles) and of phagocytosis mechanisms (pseudopod capture of bacteria) for the storage of nutrients by the egg.

Animals↗

PubMed2002

Vitellogenin precursors in the liver of the oviparous lizard, Podarcis sicula.

In reptiles, as in the other oviparous vertebrates, vitellogenin (VTG) synthesis is stimulated in the liver by ovarian estrogens. In this article, the presence of VTG precursors was detected in liver subcellular fractions of the oviparous lizard, Podarcis sicula, in the reproductive period. The rough endoplasmic reticulum (RER) and the smooth microsomal fraction (SMF), which includes smooth endoplasmic reticulum and Golgi complex, were separated by means of two different sucrose gradients. The successful separation was controlled at the electron microscope. The contents of the different compartments were extracted by means of n-octyl-beta-D-glucopiranoside detergent and subjected to SDS-PAGE. Western Blotting with homologous anti/VTG antibody revealed two immunoreactive proteins of about 84 and 70 kDa in the RER, and four proteins of about 180, 150, 60, 50 kDa in the SMF; all these proteins appeared phosphorylated and glycosylated. The differences in the molecular weight of these VTG precursors are discussed.

Animals↗

PubMed1997

Straight-line movement and competitive mate searching in prairie rattlesnakes, Crotalus viridis viridis

Males compete in various ways for mating and reproductive success. Phylogenetic factors and local ecology affect female spatial and temporal distributions, which in turn influence the form of male competition, sexual selection and mating systems. In prairie rattlesnake, Crotalus viridis viridispopulations where (1) males seek females during a brief reproductive period, (2) females are relatively few, and (3) females are widely and unpredictably distributed spatially into small discrete clusters, males should show efficient mate searching more so than time-consuming 'handling' (e.g. fighting, mate persuasion). Natural history studies and computer and mathematical modelling generate this expectation. This long-term field study of prairie rattlesnakes in Wyoming indicated that straight-line (i.e. fixed-bearing) movement by males is critical for mate location and, thus, for mating success. Males that searched along straight-line paths located and mated with more females than those having less straight movement paths. Fighting was observed rarely, and no relationship was found between males' success at mate location and body mass and/or snout-vent length. Thus a range of traits may mediate competition and mating success among male snakes.

Journal Article↗

PubMed1999

Reproductive behavioural sequences of single pairs of Atlantic salmon in an experimental stream.

We studied 12 size-matched pairs of Atlantic salmon, Salmo salar, in an experimental stream in southwest France, to determine whether fish activity and motivation changed during the course of reproduction. The absolute weight of spawners did not affect their spawning activity. On average, females deposited their eggs within 3 days in nine nests. Male and female breeding behaviours changed throughout the reproductive period. This cyclic variation in behaviour appeared to be determined in part by the activity of the other sex, as a consequence of complex interplay between the sexes, but also largely by the stage of the spawning period. During the first three ovipositions, male-female stimulus-reaction chaining became more consistent just before spawning, which may help synchronize gamete release for successful fertilization. During the last three ovipositions, sequence chaining between the sexes was less coherent, possibly as a result of reduced mate attractiveness and/or physiological limitations. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed2000

Population cycles caused by selection by density dependent competitive interactions.

Several animal species have cyclic population dynamics with phase-related cycles in life history traits such as body mass, reproductive rate, and pre-reproductive period. Although many mechanisms have been proposed there is no agreement on the cause of these cycles, and no population equation that deduces both the abundance and the life history cycles from basic ecological constraints has been formulated. Here I deduce a population dynamic equation from the selection pressure of density dependent competitive interactions in order to explain the cyclic dynamics in abundance and life history traits. The model can explain cycles by evolutionary changes in the genotype or by plastic responses in the phenotype. It treats the population dynamic growth rate as an initial condition, and its density independent fundament is Fisher's (1930, The Genetical Theory of Natural Selection, Oxford: Clarendon) fundamental theorem of natural selection that predicts a hyper-geometrical increase in abundance. The predicted periods coincide with the cyclic dynamics of Lepidoptera, and the Calder hypothesis, which suggests that the period of population cycles is proportional to the 1/4 power of body mass, follows from first principles of the proposed density dependent ecology.

Animals↗

PubMed2001

Evidence of oxidative stress in American kestrels exposed to electromagnetic fields.

Exposure to electromagnetic fields (EMFs) alters melatonin, behavior, growth, and reproduction of captive American kestrels (Falco sparverius), particularly of males. EMF exposure is a "possible" human carcinogen and associated with some neurodegenerative diseases. Oxidative stress contributes to cancer, neurodegenerative diseases, and immune disorders. We tested whether EMF exposure elicits an avian immune response and alters oxidative stress levels. Captive male kestrels were bred under control or EMF conditions equivalent to those experienced by wild kestrels. Short-term EMF exposure (one breeding season) suppressed plasma total proteins, hematocrits, and carotenoids in the first half of the breeding season. It also suppressed erythrocyte cells and lymphocyte proportions, but elevated granulosa proportions at the end of the breeding season. Long-term EMF exposure (two breeding seasons) suppressed hematocrits in the first half of the reproductive period too. Results indicate that only short-term EMF birds experience an immune response, particularly during the early half of the breeding season. The elevation of granulocytes, and the suppression of carotenoids, total proteins, and previously melatonin in the same kestrels, signifies that the short-term EMF male kestrels had higher levels of oxidative stress, due to an immune response and/or EMF exposure. Long-term EMF exposure may be linked to higher levels of oxidative stress through EMF exposure only.

Animals↗

PubMed1994

An enzyme immunoassay for salmon gonadotropin-releasing hormone and its application to the study of the effects of diet on brain and pituitary GnRH in the sea bass, Dicentrarchus labrax.

The effects of two different diets [diet 1 (D1), high protein-low carbohydrate; diet 2 (D2), low protein-high carbohydrate] on brain and pituitary gonadotropin-releasing hormone (GnRH) contents, as well as circulating steroids and vitellogenin, were studied over the reproductive period of the sea bass. Salmon GnRH was measured using a newly developed competitive enzyme immunoassay with an enzymatic tracer made of sGnRH covalently coupled to acetylcholinesterase from the electric organ of the eel Electrophorus electricus. The pituitary GnRH content of animals of both sexes fed D1 was significantly reduced at the time of spawning compared with the pre- and postspawning stages, whereas fish fed D2 did not exhibit such changes. In the brain only minor differences in the GnRH content were observed between the two diets. It is concluded that GnRH release rather than synthesis is affected in fish fed a low protein-high carbohydrate regimen. Plasma sex steroids and vitellogenin were not greatly affected by the diet.

Animals↗

PubMed1995

Dietary exposure of mink to carp from Saginaw Bay, Michigan: 2. Hematology and liver pathology.

The effects of consumption of environmental contaminants contained in carp (Cyprinus carpio) from Saginaw Bay, Michigan on various hematological parameters and liver integrity of adult female mink (Mustela vision) were determined. Mink were fed diets that contained 0 (control), 10, 20, or 40% carp prior to and throughout the reproductive period (182 days). The diets contained 0.015, 0.72, 1.53, and 2.56 mg polychlorinated biphenyls (PCBs)/kg diet and 1.0, 19, 40, and 81 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs)/g diet, respectively. Mink fed the diets containing carp showed a general dose-dependent occurrence of clinical signs commonly associated with chlorinated hydrocarbon toxicity, including listlessness, nervousness when approached, anorexia, and melena. Erythrocyte counts were less in mink exposed to Saginaw Bay carp than in controls, while the number of white blood cells was greater than in controls. Significant differences (p < 0.05) in the concentrations of neutrophils, lymphocytes, monocytes, and eosinophils were also found between the control and carp-fed groups, but are considered to be of limited clinical or biological importance. Hematocrit values for the mink fed the 20 and 40% carp diets were significantly less than those of mink in the control and 10% carp groups. There were no significant differences in hemoglobin concentrations among the groups. Necropsies revealed enlarged yellowish livers in many of the carp-fed mink, especially those fed the 40% carp diet. Liver, spleen, and lung weights of carp-fed mink were significantly greater than those of control mink.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1977

On the lympho-epithelial relationships in the human oviduct.

In order to study the lympho-epithelial relationships in human oviducts, lymphocytes situated in the epithelium were counted and the values found were correlated with differing physiological and pathological changes. In this process the following observations were made: 1. In the secretory phase there are significantly more lymphocytes to be found in the epithelium than during the proliferative phase. 2. In nonspecific purulent salpingitis the number of lymphocytes is not significantly different from that in a normal proliferative phase. 3. The values for fallopian pregnancy are significantly lower than those of a normal secretory phase and do not differ significantly from those of a normal proliferative phase. 4. The values observed for the reproductive period are significantly higher than those found postmenopausally. Examination by electron-microscopy showed that the lymphocytes in the epithelium of the uterine tube are intercellular. Pointers towards degenerative changes were not seen. It is presumed that the number of lymphocytes appearing in the epithelium of the fallopian tube depends on the hormonal activity of the ovaries.

Epithelial Cells↗

PubMed1988

Lipid synthesis and deposition by adult Richardson's ground squirrels in the natural environment.

Adult male Richardson's ground squirrels, Spermophilus richardsonii, were estimated to have emerged from hibernation in late February to early March, and adult females in mid to late March. Half of the females trapped in late March were not pregnant, as against 10% after that time. In late March males and all females had similar WAT (white adipose tissue) deposits. Between late March and early June, WAT deposits in males increased from 14 g to 64 g (a rate of 5.6 g per week). In non-parous females WAT deposits increased from 13 g to 48 g from late March to late May (4.2 g per week). Fat deposits decreased during lactation but thereafter increased from 8 g to 29 g (a rate of 6.0 g per week) between early May and early June. In males the rate of fatty acid synthesis in BAT (brown adipose tissue), liver and WAT did not change from late March to late May, and rates in the corresponding tissues of non-pregnant females were similar to those in males. Fatty acid synthesis decreased during late pregnancy and lactation. After lactation, the rate of fatty acid synthesis in all tissues increased to that in males and non-pregnant females. Males initiated fattening 5-7 weeks earlier than females. It is concluded that compared with adult males, the later immergence of adult female Richardson's ground squirrels into hibernation is due primarily to later initiation of fattening and less to differences in rate of lipid synthesis after the reproductive period. Rates of fatty acid synthesis in liver and BAT were several times greater than that in WAT. The former tissues may contribute fatty acids for prehibernatory fattening.

Adipose Tissue↗

PubMed1991

Chronic effects of cadmium on kidney, liver, testis, and fertility of male rats.

Male Wistar rats (n:20), at 5 wk of age, were given cadmium in drinking water (10 mg/L water) for 52 wk; 8 males and 20 female rats, as controls, were given tap water. At the end of 28 and 40 wk, some of the cadmium-treated males and control group male rats were sacrificed for the histopathological examination of testis, kidney, and liver. At the end of 56 wk, histopathological examinations were performed in the same way. Liver, kidney, and testis cadmium levels were also determined by atomic absorption spectrophotometry. All the cadmium-treated male rats showed pathological testicular alterations, and liver and kidney damage after chronic exposure. Cadmium levels were found to be highest in the kidney (1.009 +/- 0.034 microgram/g wet tissue in the infertile group). At the end of the 52-wk period, reproductive capacity of the cadmium-treated rats was investigated and was found to be lost in 39.89% of the animals.

Animals↗