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1.
Telotrophic ovarioles of scale insects are subdivided into tropharia (=trophic chambers) and vitellaria that contain single developing oocytes. Tropharium encloses trophocytes (=nurse cells) and arrested oocytes. The central area of the tropharium, termed the trophic core, is devoid of cells. Both trophocytes and oocytes are connected to the trophic core: trophocytes by cytoplasmic processes, oocytes by means of nutritive cords. The trophic core, processes and nutritive cords are filled with bundles of microtubules. The trophocytes contain large lobated nuclei with giant nucleoli. Fluorescent labelling with DAPI has shown that trophocyte nuclei are characterized by high contents of DNA. In the cortical cytoplasm of trophocytes, numerous microfilaments are present. The developing oocyte is surrounded by a simple follicular epithelium. The cortical cytoplasm of follicular cells contains numerous microtubules and microfilaments.  相似文献   

2.
H Kaur  R Sandhu  S S Dhillon 《Cytobios》1992,69(277):75-81
A 4 h exposure to a residual film of 15 mg 1-(3-nitrophenyl)-4,4,6-trimethyl-1H,4H-pyrimidine-2-thiol (3NTPT) dissolved in 5 ml acetone significantly inhibited ovarian growth in Dysdercus koenigii. The ovaries of treated females remained small and the trophocytes, the trophic core, the prefollicular tissue and the oogonia completely degenerated. This was followed by degenerative changes in the follicular epithelium, the interfollicular tissue and the developing oocytes. Resorption of the oocytes reduced the vitellarium to an empty tube. The follicular epithelium of the resorbed oocytes protruded into the lumen, while the interfollicular tissue completely degenerated. By day 7 after treatment, the ovaries were completely dystrophic, and this state was not reversible.  相似文献   

3.
This paper describes effects of a sublethal (1.2 mg 1–1) organophosphate, malathion, on the ovary of an air breathing catfish, Heteropneustes fossilis. The study focuses on microscopic changes that occur on ovigerous lamellae, oocytes at different stages of development and the nucleus of the immature oocyte. Also, change in estrogen levels in blood serum is investigated. Clumping of cytoplasm appears after 24 h of exposure to malathion. Clumping intensified after 48 h. Degeneration in the follicular cells was also observed. After 72 h exposure the number of nucleoli increased, nuclear materials shrunk, oocytes became adhered. With 96 h of exposure, nuclear materials of all the oocytes shrunk to a smaller clump. The oocytes fused together, and follicular epithelium became loose and ruptured. A few atretic oocytes were visible. Radioimmunoassay of the estrogen level in blood serum after 72 h of exposure of malathion showed a reduction in the level. This study showed that the histopathological condition of the gonad is reflected in malfunctioning of the endocrine system and hormonal disbalance.  相似文献   

4.
Minke whale (Balaenoptera acutorostrata) follicular oocytes were cryopreserved by a slow-step freezing procedure using ethylene glycol. The morphologically viable proportion of postthawed minke whale follicular oocytes was 39.7%. The maturity of the animals (immature and mature whales) or the presence or absence of cumulus cells (CC) did not affect the proportion of morphologically viable oocytes. Postthawed oocytes were examined for nuclear status after in vitro maturation. The presence of CC (29.1%) significantly enhanced (P < 0.05) the proportion of oocytes at metaphase I/anaphase I/telophase I stages compared to results with the absence of CC (13.5%). A total of 4 of 194 postthawed oocytes matured to the second metaphase stage after culture for 5.5 days with or without CC. The cryopreserved immature oocytes obtained from immature and mature whales were processed to examine the ultrastructure by transmission electron microscopy. Varying ultrastructural damage to the cytoplasm was observed as a result of the cryopreservation procedures. These results show that 20-30% of cryopreserved minke whale follicular oocytes can resume meiosis in vitro, but damage induced by the freezing and thawing procedures was observed.  相似文献   

5.
Prostaglandin involvement in ovulation and maturation of amphibian (Rana pipiens) ovarian follicular oocytes was investigated using in vitro-cultured ovarian follicles. Exposure of follicles to PGF2α during culture stimulated variable but generally low levels of ovulation without concomitant induction of maturation. Addition of PGF2α to cultured follicles markedly enhanced the incidence of ovulation in follicles exposed to progesterone or frog pituitary homogenate (FPH). Onset of the ovulatory process was further accelerated following addition of PGF2α to FPH-treated follicles. PGE, in contrast to PGF2α, exhibited no stimulatory effects on ovulation and consistently inhibited ovulation induction by FPH and progesterone. Cytological analysis of follicles undergoing ovulation revealed that ovulation of immature oocytes induced by PGF2α varied markedly from that seen following FPH or progesterone stimulation of follicles in vivo or in vitro. Immature oocytes in contrast to maturing oocytes were typically ovlulated with follicle cells still attached to the vitelline membrane. The observations indicate that PGF2α effected follicle rupture and contraction of the follicular epithelium and theca without prior separation of the follicle cells from the oocyte. Selective inhibitors of steroid synthesis (cyanoketone) and protein synthesis (cycloheximide) inhibited FPH-induced ovulation and maturation. PGF2α reversed the inhibitory effects of cyanoketone and cycloheximide on FPH-induced ovulation but not maturation of oocytes. Neither prostaglandins alone or in combination with progesterone or FPH induced ovulation of oocytes following removal of the follicular epithelium. Ovulatory effects of PGF2α appear to be mediated through the follicular epithelium. Results indicate that ovulation and maturation of amphibian oocytes can be induced independently of each other by separate classes of hormones. Normal synchronization of ovulation and maturation of oocytes may require the combined action of prostaglandins and steroids acting within different follicular compartments.  相似文献   

6.
The ultra- and microstructure of the female reproductive system of Matsucoccus matsumurae was studied using light microscopy, scanning and transmission electron microscopy. The results revealed that the female reproductive system of M. matsumurae is composed of a pair of ovaries, a common oviduct, a pair of lateral oviducts, a spermatheca and two pairs of accessory glands. Each ovary is composed of approximately 50 telotrophic ovarioles that are devoid of terminal filaments. Each ovariole is subdivided into an apical tropharium, a vitellarium and a short pedicel connected to a lateral oviduct. The tropharium contains 8–10 trophocytes and two early previtellogenic oocytes termed arrested oocytes. The trophocytes degenerate after egg maturation, and the arrested oocytes are capable of further development. The vitellarium contains 3–6 oocytes of different developmental stages: previtellogenesis, vitellogenesis and choriogenesis. The surface of the vitellarium is rough and composed of a pattern of polygonal reticular formations with a center protuberance. The oocyte possesses numerous yolk spheres and lipid droplets, and is surrounded by a mono-layered follicular epithelium that becomes binucleate at the beginning of vitellogenesis. Accessory nuclei are observed in the peripheral ooplasm during vitellogenesis.  相似文献   

7.
In mammals, after coitus a small number of spermatozoa enter the uterine tube and following attachment to uterine tube epithelium are arrested in a non-capacitated state until peri-ovulatory signalling induces their detachment. Whilst awaiting release low numbers of spermatozoa continually detach from the epithelium and the uterine tube reservoir risks depletion. There is evidence of attachment of spermatozoa to uterine epithelium in several species which might form a potential pre-uterine tube reservoir. In this study we demonstrate that: (1) dog spermatozoa attach to uterine epithelium and maintain flagellar activity, (2) in non-capacitating conditions spermatozoa progressively detach with a variety of motility characteristics, (3) attachment is not influenced by epithelial changes occurring around ovulation, (4) attachment to uterine epithelium slows capacitation, (5) capacitated spermatozoa have reduced ability to attach to uterine epithelium, (6) under capacitating conditions increased numbers of spermatozoa detach and exhibit transitional and hyperactive motility which differ to those seen in non-capacitating conditions, (7) detachment of spermatozoa and motility changes can be induced by post-ovulation but not pre-ovulation uterine tube flush fluid and by components of follicular fluid and solubilised zona pellucida, (8) prolonged culture does not change the nature of the progressive detachment seen in non-capacitating conditions nor the potential for increased detachment in capacitating conditions. We postulate that in some species binding of spermatozoa to uterine epithelium is an important component of the transport of spermatozoa. Before ovulation low numbers of spermatozoa continually detach, including those which are non-capacitated with fast forward progressive motility allowing the re-population of the uterine tube, whilst around the time of ovulation, signalling from as-yet unknown factors associated with follicular fluid, oocytes and uterine tube secretion promotes the detachment of large numbers of capacitated spermatozoa with hyperactive motility that may contribute to the fertilising pool.  相似文献   

8.
Zona-free oocytes of the mouse were inseminated at prometaphase I or metaphase I of meiotic maturation in vitro, and the behavior of the sperm nuclei within the oocyte cytoplasm was examined. If the oocytes were penetrated by up to three sperm, maturation continued during subsequent incubation and became arrested at metaphase II. Meanwhile, each sperm nucleus underwent the following changes. First, the chromatin became slightly dispersed. By 6 h after insemination, this dispersed chromatin had become coalesced into a small mass, from which short chromosomal arms later became projected. Between 12 and 18 h after insemination, each mass of chromatin became resolved into 20 discrete metaphase chromosomes. In contrast, if oocytes were penetrated by four to six sperm, oocyte meiosis was arrested at metaphase I, and each sperm nucleus was transformed into a small mass of chromatin rather than into metaphase chromosomes. If oocytes were penetrated by more than six sperm, the maternal chromosomes became either decondensed or pycnotic, and the sperm nuclei were transformed into larger masses of chromatin. As control experiments, immature and fully mature metaphase II oocytes were inseminated. In the immature oocytes, which were kept immature by exposure to dibutyryl cyclic AMP, no morphological changes in the sperm nucleus were observed. On the other hand, in the fully mature oocytes, which were activated by sperm penetration, the sperm nucleus was transformed into the male pronucleus. Therefore, the cytoplasm of the maturing oocyte develops an activity that can transform the highly condensed chromatin of the sperm into metaphase chromosomes. However, the capacity of an oocyte is limited, such that it can transform a maximum of three sperm nuclei into metaphase chromosomes. Furthermore, the presence of more than six sperm causes a loss of the ability of the oocyte to maintain the maternal chromosomes in a metaphase state.  相似文献   

9.
有机氯农药粘虫散(有效成分0.5%666和2.5%DDT)是防治粘虫危害的一种较好的剂型。我国北方地区小麦地套种玉米,为了防治二代粘虫危害玉米幼苗,在小麦收获前期使用,收到了良好的效果。但是由于多年连续使用,害虫的抗药性增强,防治效果降低,用药量增加;同时有机氯农药666、DDT化学性质稳定,在环境中残留期长,长期使用,会造成对土壤和作物的污染。为此,我们在1976、1979两年先后进行了粘虫散在小麦上消失动态的盆栽试验,及不同施药量、施药次数、施药时期与麦粒中粘虫散残留量关系的田间试验。并对北京市郊区几个产小麦的县进行残留量的抽查,为制订有机氯农药粘虫散在小麦上安全使用标准提供科学依据。  相似文献   

10.
The present work describes a cytogenetic study of in vitro-matured bovine oocytes designed to analyze the incidence of diploid oocytes induced by concentration of serum in the culture medium, follicle size, culture temperature and incubation time. In Experiment 1, immature follicular oocytes from follicles of the same size were cultured for 24 h in TCM-199 supplemented with increasing concentrations 0, 10, 20 and 50% of estrous cow serum (ECS). In Experiment 2, immature oocytes harvested from follicles of different sizes were cultured for 24 h in TCM-199 supplemented with 20% ECS at 39 degrees C in 5% CO2. In Experiment 3, immature follicular oocytes were matured in TCM-199 supplemented with 20% ECS at 2 different temperatures (37 degrees C or 39 degrees C) in 5% CO2. In Experiment 4, immature oocytes were matured over 4 different incubation times (24, 36 and 48 h) in TCM-199 supplemented with 20% ECS in 5% CO2. The highest concentration (50%) of ECS supplement in the culture medium induced the highest incidence of diploid oocytes. This incidence of diploid oocytes matured in vitro was higher in oocytes from follicles with a diameter between 11 and 15 mm. Finally, lower culture temperature (37 degrees C) and prolonged incubation time (48 h) also significantly (P<0.01) increased the percentage of diploid oocytes.  相似文献   

11.
Maturation-associated changes in the rat zona pellucida   总被引:1,自引:0,他引:1  
Rat follicular oocytes, arrested at prophase I, cannot be fertilized in vitro. This capacity is acquired following resumption of meiosis and a series of changes involving both the oocyte and the cumulus cells surrounding it. Oocytes exposed to sperm at different hours before ovulation show a gradual increase in the permeability of their zona pellucida (ZP). Our study examined whether the ZP, in response to the physiological stimulus for maturation and concomitant with the other oocyte--cumulus components, undergoes maturational changes. Two ZP characteristics were assessed, sensitivity to proteolysis and sperm binding. ZP surrounding oocytes and eggs were collected from five sources: 1) germinal vesicle (GV)-intact oocytes, 2) preovulatory eggs, 3) ovulated eggs isolated from oviducts of immature females, 4) fertilized eggs, 5) ovulated eggs isolated from oviducts of mature females. All ZP surrounding oocytes/eggs from groups 1-5 were dissolved by trypsin. When solubility by pronase and alpha-chymotrypsin was examined, a large variation between groups was found. All ZP from group 2 were dissolved by 0.001% pronase, compared to 0% solubility in group 4. Only 10% of the ZP surrounding GV-intact oocytes (group 1) were dissolved by this enzyme, compared to 82% in group 3. Solubility in 0.01% alpha-chymotrypsin showed a similar pattern. Capacitated sperm were incubated with eggs from groups 1 and 3. The number of sperm binding to ZP in group 3 was repeatedly higher than that in group 1. In both tests it was found that the ZP surrounding the mature eggs differ in their characteristics from ZP of GV-intact oocytes.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
During the summer of 1950 experiments were made to test the use of insecticides for preventing the fouling of oyster spat collectors by the barnacle Elminius modestus.
The insecticides used were DDT, BHC (benzene hexachloride-γ-isomer) and dieldrin (hexachloro-epoxy-octahydro-dimethano-naphthalene), made up as 5% solutions and tested on egg-box collectors and quarry tiles. The tiles were used for frequent observations on settlement.
When the solutions were sprayed on to the surfaces, in sufficient quantity to give a covering of 200 mg./ft.2 of active insecticide, none of them interfered with either barnacle or oyster settlement.
When the test surfaces were dipped in the solutions, DDT and BHC prevented barnacle settlement almost completely, while dieldrin reduced it by approximately 50%. Settlement of Ostrea edulis was also reduced on the treated surfaces.
Urea-formaldehyde resins made up as varnishes, to which DDT or BHC had been added, were also tested. A varnish incorporating 20% by weight of DDT provided an effective anti-fouling compound which lasted at least 3 months and completely prevented barnacle settlement.
The possibility of insecticides dissolving into the water and inhibiting barnacle growth on adjacent surfaces is discussed.  相似文献   

13.
Oxygen consumption by rat oocytes and cumulus cells during induced atresia   总被引:2,自引:0,他引:2  
Oxygen consumption was measured in denuded oocytes and oocyte-cumulus complexes isolated from atretic rat follicles. Adult cyclic rats or immature PMSG-treated rats were used, and follicular atresia was induced by hypophysectomy on the morning of pro-oestrus or by repeated pentobarbitone injections beginning on the day of pro-oestrus. The later stages of atresia were accompanied by meiosis-like changes in the oocytes. Oxygen consumption by oocytes that had resumed meiosis (germinal vesicle breakdown, GVB) was higher than in oocytes with an intact germinal vesicle, a change similar to that observed in oocytes maturing in healthy follicles. This may indicate that the meiotic process in the atretic follicles is similar to that in normal ones. Oxygen consumption by the cumulus cells was not altered during pentobarbitone-induced atresia. Hypophysectomy led to a rapid and marked increase in cumulus oxygen consumption in cyclic rats but there was no change in PMSG-treated young animals. Since both pentobarbitone-treatment and hypophysectomy result in follicular atresia, but changes in cumulus respiration occurred only in hypophysectomized adult rats, it is concluded that an increase in cumulus respiration is not inherent to the atretic process.  相似文献   

14.
This study addresses the role of cAMP hydrolytic isoenzyme phosphodiesterase type 3 (PDE 3) modulation on human oocyte maturation in vitro. Presence of phosphodiesterase type 3 A (PDE 3A) mRNA was confirmed in human germinal vesicle-stage (GV) oocytes. Making use of a selective PDE 3 inhibitor, Org 9935 (10 microM), oocytes retrieved from immature follicles were arrested in prophase I with a high efficiency for up to 72 h. Cumulus oocyte complexes (COCs) were retrieved in the follicular phase of the cycle before or after exposure to endogenous LH or hCG administration in vivo and randomly distributed into maturation medium with or without the PDE 3 inhibitor. Previous exposure of small follicles to LH activity in vivo had no influence on the arresting capacity of the PDE 3 inhibitor. Reversal from pharmacological arrest leads to a progression through meiosis in a normal time frame with formation of a well-aligned metaphase plate. Ultrastructure analysis of COC derived from follicles between 8 and 12 mm showed that the induced extension of prophase I arrest in vitro resulted in cytoplasm changes but not in apparent nuclear changes during culture.  相似文献   

15.
We observed the presence of follicular cells (FC) in the ovaries of Penaeus subtilis (n = 1198), which led us to classify the development of germ cells into six phases: oogonia, previtellogenic oocytes, primary and secondary vitellogenic oocytes, mature oocytes and atretic oocytes. The FC changes their shape according to the development of germ cells and showed a different distribution along the ovary, which allowed differentiating vitellogenic oocytes into primary and secondary. We also observed that the postovulatory follicles (POF) are composed of follicular cells. The presence of POF in penaeids ovaries is rarely reported, but allows the differentiation between spent and resting stages, commonly grouped in reproductive biology research. Furthermore, observation of ovarian lining was useful to differentiate immature females from females that had spawned at least once. Thus, ovarian development was classified into six stages: immature, early developing, advanced developing, ripe, spent and resting. The distribution and shape variations of FC, ovarian lining features and presence of POF were considered crucial for the classification of ovarian maturation stages. The methods developed here may improve estimates of their reproductive cycle, size at first maturity and spawning season, which are important variables in future studies of the reproductive dynamics.  相似文献   

16.
To determine if newly synthesized protein is imperative for the resumption of meiosis in bovine follicular oocytes collected from small antral follicles, cumulus-enclosed and denuded oocytes were cultured in TCM-199 both with and without various concentrations of the protein synthesis inhibitor, cycloheximide. After 11 h of culture in inhibitor-free medium, all oocytes had undergone germinal vesicle breakdown (GVBD). However, when concentrations of more than 1.0 mug/ml cycloheximide were added to the medium, the meiotic resumption of bovine oocytes was completely blocked. This inhibitory effect of cycloheximide was fully reversible after removal of the inhibitor from maturation media. Germinal vesicle breakdown following removal of cycloheximide occurred twice as fast as in the control medium. Nevertheless, when oocytes were arrested at the germinal vesicle (GV) stage by cycloheximide, a significantly higher proportion of chromatin condensation (40 to 57%) was observed in denuded oocytes than in cumulus-enclosed oocytes (11 to 22%). Thus the cycloheximide treatment could not prevent the chromatin condensation in only denuded oocytes. We conclude that protein synthesis is a prerequisite for GVBD in bovine follicular oocytes and that cumulus cells are responsible for the complementary regulation of the chromatin condensation at the GV stage, regardless of protein synthesis in the oocytes.  相似文献   

17.
The present investigation describes the ultrastructural changes which occur at the surface and in the cytoplasm of developing oocytes of the lobster, Homarus americanus, during vitellogenesis. The immature oocytes showed no surface specializations of the oolemma and no pinocytotic activity was observed. Horseradish peroxidase (HRP) tracer studies showed penetration of the tracer into the perivitelline space, but no uptake by the oocytes. The surfaces of oocytes examined during vitellogenesis, when yolk protein accumulation was maximal, exhibited numerous microvilli that projected into the perivitelline space, often appearing to be embedded in the follicular cell mass. In addition, the plasma membrane of vitellogenic oocytes contained many pinocytotic pits frequently situated at the bases of microvilli. The perivitelline space was engorged with electrondense material which appeared similar to that contained in pinocytotic structures of the oocytes. Vitellogenic oocytes incubated in HRP showed uptake of tracer reaction product by the coated pits and vesicles of the oolemma. Aggregation and subsequent fusion of these vesicles into large multivesicular bodies of ingested material were also observed in vitellogenic oocytes. Animals artificially induced to undergo vitellogenesis exhibited modulations of oocyte ultrastructure similar to those of normal vitellogenesis, notably, pinocytotic incorporation of extra-oocytic material and hypertrophy of oocyte surface microvilli. This study supports the hypothesis for a dual source of yolk protein in the American lobster.  相似文献   

18.
Indoor cultures of the green alga Scenedesmusacutus were tested for sensitivity to varying concentrations of seven insecticides and three fungicides. The growth rates of the organisms were considerably reduced by BHC and DDT analogues even at low concentrations of 500 ppb and 1 ppm. Lindane above 5 ppm and Technical BHC and DDT at 100 ppm were lethal to this alga. Of the three fungicides, TMTD (Tetra Methyl Thiurum Disulfide) was most toxic resulting in death of the culture at 10 and 100 ppm. Blitox (Copper-oxy chloride) and Zineb (Zinc Ethylene-Bis dithiocarbamate) considerably retarded growth at all concentrations. This alga was more sensitive to Lindane, BHC (Technical), DDT and TMTD. The growth rate appeared to be influenced by the concentration of pesticide present in the algal culture. As Scenedesmusacutus is being considered as a source of Single Cell Protein (SCP) for human consumption, knowledge on the sensitivity of this alga to pesticide contamination will be useful.  相似文献   

19.
Summary The observation that tissue-type plasminogen activator (tPA) activity increased dramatically in preovulatory follicles has led to the hypothesis that plasminogen activation is causally related to follicle rupture. With immunohistochemistry, we have studied the appearance of tPA in ovaries of immature rats induced to ovulate and in adult cycling rats. Treatment of immature female rats with a single dose of pregnant mare serum gonadotropin (PMSG) induced follicular maturation. A subsequent human chorionic gonadotropin (hCG) injection resulted in follicle rupture 12–14 h later. PMSG treatment alone did not induce appearance of tPA-immunoreactive cells in any ovarian compartment. After hCG stimulation, however, theca cells, granulosa cells, and oocytes of pre- and postovulatory follicles displayed distinct tPA immunoreactivity. Fibroblastlike cells in the theca layers and tunica albuginea of the follicle apex also demonstrated localized cytoplasmic tPA reactivity. In addition to tPA synthesis in preovulatory follicles, hCG also induced tPA staining in the theca (but not granulosa) layers of non-ovulatory follicles. At 24 h after hCG treatment, there was a marked tPA staining in developing corpora lutea, ovulated ova, and oviductal epithelium. Ovaries from regularly cycling adult rats displayed a similar ovulation-related pattern of tPA immunostaining. The appearance of tPA in different cell types of the preovulatory follicle and in the fibroblast-like cells at the follicle apex, strengthens the hypothesis of a direct involvement of tPA in follicle rupture. Presence of tPA in postovulatory oocytes, cumulus cells, and surrounding oviductal epithelium may also indicate a role for tPA in the transfer of eggs in the oviduct.This work was supported by NIH Research Grants HD-14084; 12303  相似文献   

20.
魏鸿钧 《昆虫学报》1959,(4):325-335
粘虫Pseudaletia separata(Walker)是粮食作物的毁灭性害虫,也是全国农业发展纲要(修正草案)所规定要消灭的八大害虫之一。粘虫在大发生时为害面积很广,虫体发育迅速,食量很大,过去多采用人工器械捕打办法,但不能澈底解决问题,尤其在作物密植的情况下,捕打也发生了困难,常因捕打时将作物践踏而引起损失,因此要求在发生时应用化学防治方法,以达到迅速消灭为害之目的。  相似文献   

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