橘小实蝇雌雄成虫生殖系统中可培养细菌的分离鉴定

本研究分离鉴定了来自赣南脐橙基地橘小实蝇Bactrocera dorsalis (Hendel)雌性和雄性成虫生殖系统中的可培养细菌.采用LB培养基分离纯化和菌株16S rRNA基因序列分析相结合的方法,从饲养10 d的橘小实蝇雌雄成虫生殖系统,获得15株具有不同表观特征的细菌,分属变形菌门Proteobacteria...     

The sexual system of fetal and adult male rats of 2 strains after prenatal exposure to glucocorticoids

Testosterone level in male fetuses and adults after glucocorticoid injection to their mothers on 16-th and 18-th days of pregnancy as well as morphometric characteristics of male adult reproductive system of two outbred strains (aggressive and domesticated) were investigated. Prenatal hormonal treatment resulted in genotype-dependent changes in testosterone level in 21-day-old male fetuses; it was decreased in fetuses of domesticated rats and increased in fetuses of aggressive rats. The direction of these changes coincided completely with the subsequent changes in relative weight of preputial gland and seminal vesicles in adults. Thus, the level of glucocorticoids during prenatal period plays an important role in reproductive system development and the character of the action depends on the genotype.     

Effect of maternal adrenocorticotropin injections on the differentiation of sexual behavior of the offspring

Male and female rats were prenatally exposed to high levels of corticosteroids, by treatment of their mothers with ACTH, during the last third of pregnancy. In the females, treatment increased the ano-genital distance at birth, but no effect on sexual differentiation could be detected in the adult animals: They had normal cyclic reproductive function and female lordotic sexual behavior. The prenatal treatment demasculinized the males, who showed decreased ability for complete male copulatory behavior. The demasculinizing effect of prenatal corticosteroids was, however, particularly pronounced in certain litters, while not affecting others at all.     

Ameliorative Effect of Carvacrol on Cisplatin‐Induced Reproductive Damage in Male Rats

Cisplatin (CP) treatment causes the damage in male reproductive system. Carvacrol (CARV) is an antioxidant that is naturally found in some plants. We aimed to investigate the effect of CARV on CP‐induced reproductive toxicity in male rats. Eighteen adult male Sprague–Dawley rats were used. The control group (n = 6) was treated orally with physiological saline (PS) daily for 14 days and a single intraperitoneal (IP) PS injection on day 10. The CP group (n = 6) was administered with daily oral PS for 14 days and a single IP injection of 10 mg/kg CP on day 10. The CARV + CP group (n = 6) was treated with daily 75 mg/kg oral CARV for 14 days and a single IP injection of 10 mg/kg CP on day 10. CP treatment caused the damage on some spermatological parameters (motility, live sperm rate, and abnormal sperm rate), increased the oxidative stress, and induced testicular degeneration and apoptosis. However, CARV treatment mitigates CP‐induced reproductive toxicity.     

Participation of the brain serotoninergic system in creating the stress reactivity of the hypophyseal-adrenal axis

The concentration of corticosteroids in the blood of rats was shown to increase in response to the immobilization stress at an earlier age than the brain serotonin metabolism changes. The level of corticosteroids in blood increased in response to the intraperitoneal serotonin injection also earlier than the reaction to the serotonin injection in the brain lateral ventricle sets up. The increase of the reaction of hypophysial-suprarenal system to stress during the period from the 12th till the 16th day of postnatal development coincided with the changes in serotonin metabolism in the brain stem and the reaction to serotonin injection in the brain lateral ventricle. It is suggested that the system of serotonin brain neurons connected with the hypophysial-suprarenal complex matures later tran the serotonin receptors in the periphery; the reaction to immobilization may be realized at the early developmental stages without the participation of brain serotonin.     

Seasonal Variations in the Expression of the mRNA Encoding ß1-Adrenoceptor and AA-NAT Enzyme,and in the AA-NAT Activity in the Pineal Gland of Vizcacha (Lagostomus maximus maximus) – Correlation With Serum Melatonin

The vizcacha is a photoperiodic rodent living in the southern hemisphere. The adult males exhibit an annual reproductive cycle characterized by a gonadal regression period during winter with, in some animals, an almost complete loss of spermatogenesis. In this study, we investigated whether biochemical parameters involved in melatonin synthesis in the vizcacha pineal gland exhibited an annual rhythm in parallel with the annual reproductive cycle. By use of in situ hybridization, an annual variation of mRNA encoding ß 1 -adrenoceptor was shown, with a maximum during autumn and winter. In situ hybridization for mRNA encoding AA-NAT enzyme also exhibited an annual rhythm with the lowest and highest levels in May and August, respectively. Likewise, in August the activity of arylalkylamine N-acetyltransferase enzyme also reached a maximum. Finally, dertermination of the serum concentrations of melatonin by use of radioimmunoassay showed an increase during winter. Moreover, our results are in concordance with several biochemical and morphological parameters of the reproductive axis of the male vizcacha, which support the reproductive rhythmicity of this rodent. Thus, our data suggest that the pineal gland and melatonin, which is activated via the sympathetic system, could be involved in the photoperiodically dependent annual reproductive behavior of the vizcacha.     

Effect of melatonin on reproductive system in male rat, treated with estrogen in the first day of life.

The study aimed at demonstrating the possible stimulating or inhibitory effect of melatonin on reproductive system of male rats, the function of which was altered by single diethylstilbestrol dose introduced in the first day of life. The single estrogen dose in the first day of life induced in the studied rats, after they reached the adult age, inhibition of spermatogenesis as well as morphological and functional alterations in accessory sexual glands. This was associated with high level of LH gonadotrophin and with lowered testosterone level in the serum. Additional administration of melatonin between 45th and 84th day of life accentuated the above described changes induced by the single estrogen injection. Results of the studies demonstrated that melatonin in the experimental model not only failed to stimulate but provided an additional inhibitory effect on reproductive system in male rat.     

Response of the mink reproductive system to hormonal stimulation in october as a prognostic criterion of folluculogenesis and fertility

The responsess of the mink reproductive systems in October to a single intramuscular injection of chorionic gonadotropin (CG, Profasi R, Italy) at doses of 10, 20, 50, and 100 IU was studied. The estrous cycle state, folliculogenesis, and reproductive parameters of the female minks were estimated. To evaluate functional polymorphism in the reproductive system of the females in response to the CG injection, a dose of 20 IU was chosen. On the sixth day after administration of this dose of CG, the females (n = 185) were distributed according to the stages of the estrous cycle as follows: anestrus—71 animals (38.4%), anestrus-proestrus—37 (20.0%), proestrus—30 (16.2%), proestrus-estrus—14 (7.6%), estrus—33 (17.8%). In the females of the “anestrus-proestrus” and “proestrus” groups as compared with the other groups as well as with control, a statistically significantly higher fertility was revealed. The study of folliculogenesis in the females with different parameters of the estrous cycle in November demonstrated the high level of fertility to be due to ability of these females to produce, under influence of the CG injection, the maximal number of mature follicles. A high heritable responsiveness of the reproductive system of the females to the CG injection (coefficient of realized heritabilityh = 0.64; the calculation made on the data for the sisters) indicates that this method may be an additional criterion in the selection of females for fertility.     

Differential expression and estrogen response of lactoferrin gene in the female reproductive tract of mouse,rat, and hamster

Lactoferrin, an iron-binding glycoprotein, kills bacteria and modulates inflammatory and immune responses. Presence of lactoferrin in the female reproductive tract suggests that the protein may be part of the mucosal immune system and act as the first line of defense against pathogenic organisms. We have discovered that lactoferrin is a major estrogen-inducible protein in the uterus of immature mice and is up-regulated by physiological levels of estrogen during proestrous in mature mice. In the present study, we examined lactoferrin gene expression and its response to estrogen stimulation in the female reproductive tract of several strains of immature mouse, rat, and hamster. The lactoferrin expression in the cycling adult female rat was also evaluated. Lactoferrin gene polymorphism exists among the different mouse strains. In the three inbred mouse strains studied, lactoferrin gene expression is stimulated by estrogen in the immature uterus, although it is less robust than in the outbred CD-1 mouse. We found that the lactoferrin gene is constitutively expressed in the epithelium of the vagina and the isthmus oviduct; however, it is estrogen inducible in the uterus of immature mice and rats. Furthermore, lactoferrin is elevated in the uterine epithelium of the mature rat during the proestrous and estrous stages of the estrous cycle. Estrogen stimulation of lactoferrin gene expression in the reproductive tract of an immature hamster is limited to the vaginal epithelium. The present study demonstrates differential expression and estrogen responsiveness of the lactoferrin gene in different regions of the female rodent reproductive tract and variation among the rodent species studied.     

Developmental success and reproductive incompatibility among populations of the European red mite,Panonychus ulmi (Acari: Tetranychidae)

Developmental success on 47 species of plant and reproductive compatibility were studied for four strains of the European red mite,Panonychus ulmi (Koch), collected from dwarf bamboo, elm and apple trees. The host range was variable in those strains and there was no plant species on which all four strains were able to reach maturity.Intra-populational crosses in the dwarf-bamboo strain and the two apple strains of mites, as well as crosses between the two apple strains, gave both female and male progeny. Inter-populational crosses between the dwarf-bamboo and apple strains produced only male progeny, as in the case where females of each strain were kept virgin, indicating that these two were reproductively incompatible and had an arrhenotokous reproductive system. When females of the elm strain were crossed with males of the elm, dwarf-bamboo or apple strain, no males were produced, as in the case for virgin females of the elm strain which had a thelytokous reproductive system. It is thus concluded that the strains derived from different host species were reproductively incompatible with one another.     

Life table parameters, reproductive rate, intrinsic rate of increase, and estimated cost of rearing Podisus maculiventris (Heteroptera: Pentatomidae) on an artificial diet.

The impact of an insect-free artificial diet provided at nymphal and/or adult stage upon the developmental rate, life table parameters, and fertility table parameters was examined for Podisus maculiventris (Say). This study showed that when fed an insect-free artificial diet during both the nymphal and adult stage, developmental time was prolonged, preoviposition period was extended, and reproductive rate (R0) and intrinsic rate of increase (r) were significantly lower than when fed larval insect prey at both nymphal and adult stages. Additionally, feeding larval prey to adults reared as nymphs on an artificial diet significantly increased the proportion of fertile females, the number of eggs laid by mated females, the reproductive rate and intrinsic rate of increase, but the mean generation time was not significantly different. Likewise, feeding artificial diet to adults reared on larval prey resulted in a significant reduction in reproductive rate and intrinsic rate of increase. The "realized" cost to rear P. maculiventris on the artificial diet was calculated (as the cost to double the population size) using raw material cost, fertility table parameters and doubling time values. Raw material cost for rearing P. maculiventris colony on Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) was only 1.4 times higher than the cost of artificial diet raw materials required to rear the same size colony. However, the realized cost of rearing was 3.5 times higher when rearing on artificial diet because of the prolonged developmental time and reduced reproductive output. The cost efficiency of rearing a beneficial insect on an artificial diet that decreases the intrinsic rate of increase of a colony is discussed, as well as the advantages and disadvantages of supplementing adult diets with natural prey at the reproductive stage.     

Plantless rearing of the zoophytophagous bug Nesidiocoris tenuis

Nesidiocoris tenuis Reuter (Heteroptera: Miridae) is widely distributed in the Mediterranean area, where it is used as an augmentative biological control agent of several pests. This zoophytophagous predator maintains a close relationship with its host plants using them not only to feed on, but also as an oviposition substrate. In the present study, a plantless rearing system was developed and developmental and reproductive parameters of bugs that had no access to plant material were compared with their counterparts living on plants. Eggs deposited in an artificial substrate took longer to develop and had lower hatching rates than those laid in tomato leaves. However, the biological parameters of nymphs that had hatched from the artificial substrate did not differ from those of nymphs that had emerged from plants, suggesting that, besides water, no essential nutrients are absorbed from the oviposition substrate during embryogenesis. Our results regarding the role of plant feeding indicate that water acquisition is the critical function of phytophagy in N. tenuis. In addition, supplementary nutrients derived from plants had a positive effect on adult weight and significantly enhanced survival in the absence of prey. Plantless rearing for five generations led to a prolonged preoviposition period and lower egg hatching rates and adult weights, but other developmental and reproductive parameters were not adversely affected. Our experiments suggest that prolonged plantless rearing of N. tenuis is possible provided that the mirid has access to a nutritionally superior food like Ephestia kuehniella eggs.     

Reproductive aspects in female rats exposed prenatally to hydrocortisone

We investigated the effects of hydrocortisone during the prenatal period and its later repercussion on reproductive aspects of female rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of pregnancy. Although the present study was not intended to identify mechanisms of toxicity, the treatment with hydrocortisone in the last period of pregnancy presented no signs of toxicity. The efficacy of the hydrocortisone in reducing the adrenal wet mass and plasma corticosterone levels immediately after delivery in both the treated mothers and in respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. In addition, the treatment with hydrocortisone did not interfere in the development of the female descendants until puberty. However, it affected the estrous cycle and fertility. Probably, the prenatal exposure to corticosteroids had altered at least partially the hypothalamus-pituitary-gonadal axis, resulting in the damages observed in adult life. These results indicate that the use of the hydrocortisone at a dose that apparently does not endanger the neonate led to undesirable effects in the adult reproductive phase, resulting in later deleterious alteration of the reproductive physiology in female rats.     

Impact of inbreeding on performance of the predator Podisus maculiventris

Effects of inbreeding on the development and reproduction of the predatory pentatomid Podisus maculiventris were assessed throughout 30 generations following introduction in the laboratory. Developmental and reproductive fitness of two mildly inbred lines did not differ dramatically from that of a reference population. In most generations, egg weight, egg hatch and developmental rate of nymphs were greater in the reference strain than in both inbred strains, but fecundity and longevity did not differ among strains. In the 30th generation, fecundity of all strains had dropped to about half of that observed in the 15th generation, which was presumably related to non-genetic factors. There were consistent differences among strains for adult body weight and size, indicating heritable variation. A positive relationship between weight at day 14 and humeral width of P. maculiventris females was found, but neither of these parameters was associated with total fecundity. In the 30th generation, predators from both inbred lines had generally similar predation capacities to those from the reference population. No significant relationship could be detected between body weights and predation rates of either nymphs or adults. The use of inbreeding to minimize selective adaptation during rearing or to select for favourable traits in P. maculiventris is discussed.     

Effects of experimental warming on wild and transgenic oriental fruit fly,Bactrocera dorsalis

Climate change may influence the application efficiency of transgenic marking, such as in mark–release–recapture (MRR) experiments or sterile insect technique (SIT). Wild and transgenic fruit flies of Bactrocera dorsalis were subjected to oscillating regimes that represent current temperature conditions (mean: 28.6°C) and various future possible scenarios (means: 30.0, 32.5 and 35.0°C). As the temperature was increased to 30.0°C, the negative effects on adult fecundity and demographic parameters (net reproductive rate and intrinsic rate of increase) of only the transgenic cohorts increased. With a moderate warming (32.5°C), negative effects were observed on the net reproductive rate for both fly strains, and these effects on the life‐history traits (adult fecundity and longevity) and intrinsic rate of increase were stronger in the transgenic than in the wild cohorts, with reference to the trait values at 30.0°C. A severe warming (35.0°C) resulted in the failure of all individuals of both fly strains to reach adulthood. We suggest parametrical adjustments or decreased differences in fitness with refined transgenesis under current and future climate conditions, which can reduce the marking limitations of pest management and eradication programmes.     

温度和食物浓度对三品系萼花臂尾轮虫实验种群动态的影响

应用个体培养方法,研究了温度(20、2和30 ℃)和藻类食物浓度(1.5×10₆、3.0×10₆、6.0×10₆和9.0×10₆ cells·ml^-1)对青岛、芜湖、广州三品系萼花臂尾轮虫种群动态的影响.结果表明,温度仅对轮虫的世代时间和种群内禀增长率有显著影响,而品系对所有生命表参数均无显著影响.轮虫种群的内禀增长率随培养温度的升高而增大,世代时间则随培养温度的升高而缩短.食物浓度仅对轮虫的生命期望值和平均寿命有显著影响,品系对轮虫的净生殖率、世代时间、生命期望值和平均寿命也有显著影响.三品系间,以广州品系轮虫的净生殖率、世代时间、生命期望值和平均寿命最大,芜湖品系最短.当食物浓度为3.0×10₆ cells·ml^-1时,轮虫的生命期望值和平均寿命最长,9.0×10₆ cells·ml^-1时最短.各品系轮虫的净生殖率、世代时间、总生殖率、生命期望值和平均寿命均随培养温度的升高而减小,广州品系的净生殖率除外.轮虫种群的内禀增长率和广州品系轮虫的总生殖率则随培养温度的升高而增大.青岛和广州品系轮虫的各生命表参数,均与食物浓度呈曲线相关,但芜湖品系仅世代时间、平均寿命和生命期望值随食物浓度的增大而缩短.     

温度和食物浓度对三品系萼花臂尾轮虫实验种群动态的影响

应用个体培养方法,研究了温度(20、25和30℃)和藻类食物浓度(1．5×10^6、3．0×10^6、6．0×10^6和9．0×10^6cells·ml^-1)对青岛、芜湖、广州三品系萼花臂尾轮虫种群动态的影响．结果表明,温度仅对轮虫的世代时间和种群内禀增长率有显著影响,而品系对所有生命表参数均无显著影响．轮虫种群的内禀增长率随培养温度的升高而增大,世代时间则随培养温度的升高而缩短．食物浓度仅对轮虫的生命期望值和平均寿命有显著影响,品系对轮虫的净生殖率、世代时间、生命期望值和平均寿命也有显著影响．三品系间,以广州品系轮虫的净生殖率、世代时间、生命期望值和平均寿命最大,芜湖品系最短．当食物浓度为3．0×10^6cells·ml^-1时,轮虫的生命期望值和平均寿命最长,9．0×10^6cells·ml^-1时最短．各品系轮虫的净生殖率、世代时间、总生殖率、生命期望值和平均寿命均随培养温度的升高而减小,广州品系的净生殖率除外．轮虫种群的内禀增长率和广州品系轮虫的总生殖率则随培养温度的升高而增大．青岛和广州品系轮虫的各生命表参数,均与食物浓度呈曲线相关,但芜湖品系仅世代时间、平均寿命和生命期望值随食物浓度的增大而缩短．     

Variations in life tables of geographically isolated strains of the mosquito Culex quinquefasciatus

Variations in the life tables and other biological attributes of four strains of Culex quinquefasciatus Say (Diptera: Culicidae) from geographically isolated regions of India that had been reared to the fifth generation in the laboratory were assessed under a standardized rearing regime under constant laboratory conditions. Two strains from arid habitats [Jodhpur (JD) and Bikaner (BKN)], one from a semi-arid inland habitat [Bathinda (BTH)], one from a semi-arid coastal habitat [Jamnagar (JMN)] and a standard laboratory strain (LAB) were compared. Horizontal life-table parameters were measured for each strain. Egg mortality ranged from 4.4% (JD and BTH) to 19.5% (BKN). The lowest rate of adult emergence and highest female : male ratio were found in BKN, and the highest rate of adult emergence and lowest female : male ratio were recorded in BTH. The egg-hatching period was longest in BTH and shortest in LAB. The duration from oviposition to adult emergence was longest in JD and shortest in LAB. Females lived longer than males in all strains. The net reproductive rates (R(0) ) of all field-derived strains (122.9-162.2) differed significantly between strains and were significantly greater than that of LAB (107.6). Similarly, both the intrinsic rate of increase (r(m) ) and finite rate of increase (λ) were found to be lower in LAB than in the field strains, but the mean generation time (T) and doubling time (DT) were longest in LAB. For several life-table attributes, JD and BTH clustered together and were more similar to JMN than to BKN and LAB. The results indicate that BTH, BKN and JD can be characterized as r-strategists, more so than JMN. Overall fecundity increased with age. Differences in annual temperature ranges and mean annual rainfall between locations were positively correlated (r = 0.46-0.97) with egg production, female life expectancy, R(0) , r(m) , λ and T. The results suggest that strains of Cx. quinquefasciatus from different geographical areas with contrasting habitats vary in their survival and reproductive strategies accordingly.     

Local adaptation and effect of host genotype on the rate of pathogen evolution: an experimental test in a plant pathosystem

Abstract Virulence is thought to be a driving force in host–pathogen coevolution. Theoretical models suggest that virulence is an unavoidable consequence of pathogens evolving towards a high rate of intrahost reproduction. These models predict a positive correlation between the reproductive fitness of a pathogen and its level of virulence. Theoretical models also suggest that the demography and genetic structure of a host population can influence the evolution of virulence. If evolution occurs faster in pathogen populations than in host populations, the predicted result is local adaptation of the pathogen population. In our studies, we used a combination of molecular and physiological markers to test these hypotheses in an agricultural system. We isolated five strains of the fungal pathogen Mycosphaerella graminicola from each of two wheat cultivars that differed in their level of resistance to this pathogen. Each of the 10 fungal strains had distinct genotypes as indicated by different DNA fingerprints. These fungal strains were re‐inoculated onto the same two host cultivars in a field experiment and their genotype frequencies were monitored over several generations of asexual reproduction. We also measured the virulence of these 10 fungal strains and correlated it to the reproductive fitness of each fungal strain. We found that host genotypes had a strong impact on the dynamics of the pathogen populations. The pathogen population collected from the moderately resistant cultivar Madsen showed greater stability, higher genotype diversity, and smaller selection coefficients than the pathogen populations collected from the susceptible cultivar Stephens or a mixture of the two host cultivars. The pathogen collection from the mixed host population was midway between the two pure lines for most parameters measured. Our results also revealed that the measures of reproductive fitness and virulence of a pathogen strain were not always correlated. The pathogen strains varied in their patterns of local adaptation, ranging from locally adapted to locally maladapted.