Female Progeny Research Articles

Effects of maternal late-gestation nutrition on dam and subsequent progeny growth and performance of beef cattle

Our objective was to evaluate the effects of forage type and supplementation level on dam and subsequent progeny growth and progeny reproductive performance in heifers. Multiparous, May-calving cows (n = 652) were managed over 6 production cycles and arranged in a 2 × 2 factorial. They were assigned to 1 of 2 forage types: subirrigated meadow (M) or upland range (R) for 116 ± 2 d, and then 1 of 2 supplementation groups: no supplement (NoSp) or 0.45 kg/d of 33% CP (DM) supplement (Sp) for 85 ± 2 d. Body weight gain was greatest for MSp cows and intermediate for MNoSp cows, followed by RSp and then RNoSp cows ( P = 0.02). Treatment-period BCS gain was increased ( P < 0.01) in Sp cows. Sex-specific differences in postnatal progeny BW through development were detected ( P ≤ 0.05). Heifer progeny increased ( P = 0.01) percent mature BW at breeding. Pregnancy rate as a primiparous cow was increased ( P = 0.02) by maternal meadow grazing. Heifer progeny’s first calf BW ( P = 0.04) and risk of dystocia was increased ( P = 0.04) by dam supplementation. These results suggest differences in maternal late-gestation diet composition due to differences in supplementation and forage specie type and growth result in altered postnatal phenotypes of both female and male progeny.

Sex-specific transgenerational effects of adolescent morphine exposure on short-term memory and anxiety behavior: Male linage

Current estimates indicate that opioid use and misuse are a rising epidemic, which presents a substantial socioeconomic burden around the world. Chronic opioid consumption, specifically during the critical period of adolescence, can lead to enduring effects not only in individuals but also in future generations. Utilizing rodent model, we have previously reported the impacts of paternal exposure to chronic morphine during adolescence on neurobehavioral features in progenies. Currently, the potential transgenerational effects of paternal morphine exposure during adolescence on anxiety-like behavior and short-term memory remains unknown.Male Wistar rats were exposed to increasing doses of morphine for ten days in adolescence (PND 30–39). Thereafter, following a 30-days drug-free period, the treated male rats mated with naïve females. The anxiety-like behavior and short-term memory performance were assessed in adult male and female offspring (PND 60) using open field and Y-maze tests.Both male and female progenies of morphine-treated sires revealed a significant reduction in the movement velocity compared to progenies of saline-treated sires as measured by open field test. Morphine-sired male but not female offspring also showed a non-significant large decreasing effect on time spent in the center and frequency of entries to the center of open field box. Moreover, a significant reduction in the number of entries and percent of time spent in the novel arm was observed in male and female morphine-sired offspring, as measured using Y-maze test. Growth outcomes also did not demonstrate any difference in the number of dam’s fertility, pups birth, and death between morphine-sired and saline-sired groups in both sexes.Collectively, paternal exposure to morphine during adolescence induces sex-specific and selective disturbances in short-term memory while anxiety-like behavior was slightly disturbed.

Oil Palm Inflorescence Sex Ratio and Fruit Set Assessment in dura × pisifera Biparental Progenies on Fibric Peat Soil

This study investigated oil palm inflorescence sex ratio (ISR) and fruit set (FS) yield among 24 dura × pisifera biparental progenies on fibric peat soil, hybridized from ten genetic origins. Three-month intervals of data collection on ISR and “S-shape” procedure for FS determination were carried out in an independent complete randomized design for one year. Based on the assessment of individual progenies, analysis of variance revealed the existence of genetic heterogeneity. Five of the progenies had the highest ISR above 90%. However, 20.83% of the progenies (PK4841, PK4674, ECPHP415, ECPHP550, and PK4118) had the best normal range of ISR, indicating FS declined being influenced by ISR. Therefore, only 12.50% of the progenies (PK4674, PK4465, and PK4482) were above 60% FS critical level. Correlation analysis verified that ISR depends on the female flower and progeny PK4674 (65.78%) and PK4465 (62.62%) had the best FS and fruit to bunch. Among the parental origins, Deli Serdang × Cameroon was statistically the best for male flower production at 29.40% and ISR at 72.22%. The highest FS was recorded in Deli Banting × AVROS (54.00%) and Angola × AVROS (53.78%). However, molecular research, such as microsatellite molecular markers if concurrently used as a selection criterion with the present conventional study, could present further details to complement the present findings.

Does maternal exposure to nicotine affect the oocyte quality and reproductive capacity in adult offspring?

Gonadal development begins in the intrauterine phase and females from most species are born with an established oocyte reserve. Exposure to drugs during gestation can compromise the offspring health, also affecting the gametes quality. Nicotine, the main component of cigarettes, is an oxidant agent capable of altering the fertility in men and women. As female gametes are susceptible to oxidative stress, this drug can damage the oolemma and affect oocyte maturation, induce errors during chromosomal segregation and DNA fragmentation. Oocyte mitochondria are particularly susceptible to injuries, contributing to the oocyte quality loss and embryonic development disruption. Thus, considering the high number of women who smoke during pregnancy, while significant events are occurring in the embryo for future fertility of offspring, we seek to verify the quality of the oocytes from adult rats exposed to nicotine during intrauterine phase and breastfeeding. Pregnant Wistar rats received nicotine by osmotic mini-pumps and the female progenies were evaluated in adulthood for oocyte quality (viability, lipid peroxidation, generation of reactive oxygen species and mitochondrial integrity) and reproductive capacity. Embryos (3dpc) and fetuses (20dpc) generated by these rats were also evaluated. The results showed that the dose of 2 mg/kg/day of nicotine through placenta and breast milk does not affect the number of oocytes and the fertility capacity of adult rats. However, it causes some morphological alterations in oocytes, mitochondrial changes, embryonic fragmentation and disruption of fetal development. The malformations in fetuses generated from these gametes can also indicate the occurrence of epigenetic modifications.

Influence of temperature on the restoration of the ability of Trichogramma principium to undergo diapause

It is known that the progeny of post-diapause females of some insects are insensitive to diapause-inducing stimuli. In aphids the duration of the ‘interval timer’ (the restoration of the ability to diapause) decreases with temperature. However, the parameters of this temperature dependence are unknown. We investigated the restoration of the ability to undergo diapause in 9–16 sequential post-diapause generations of the egg parasitoid Trichogramma principium Sug. et Sor. (Hymenoptera: Trichogrammatidae) over a period of 120–150 days at different constant and variable temperatures. This revealed a strong linear correlation between mean temperature and the rate of the restoration of the ability to diapause. The lower temperature threshold of this dependence was not significantly different from that of the thermal dependence of the rate of preimaginal development. The restoration rate depended on the mean temperature for the whole period of development rather than on the temperature conditions during the development of the thermosensitive stages determining the incidence of diapause in the progeny. The results of this study indicate that the duration of the interval timer is determined by the rate of development (or, more generally, by the rate of metabolism) rather than by the mechanisms controlling the photothermal regulation of diapause.

Transgenerational effect of insecticides on juvenile development time of the Sweetpotato whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae)

Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is a highly efficient parasitoid that has been commercially used for augmentative biological control of the sweetpotato whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The success of control efforts with this parasitoid could be compromised by the use of non-selective pesticides. This study was conducted to determine if acetamiprid, imidacloprid, thiamethoxam, spinetoram, and sulfoxaflor had transgenerational effects on juvenile development of E. mundus. The mean development time from oviposition (OVP) to first sign of parasitism (FSP) for progeny of females treated with control was 9.03 days, which was the shortest compared to the insecticide treatments. After FSP, the control groups reached their pre-pupal (PP) stage in an average time of 3.85 days, while it was in the range of 3.98–4.46 days for insecticide-treated groups. The developmental period from pre-pupal to black-eyed pupal stage ranged from 2.32–2.69 days for parasitoids treated with insecticides, but it was 2.22 days for the control group. The overall mean development time—from oviposition until adult emergence—was 16.24 days for control, which was statistically shorter than all other treatments. Spinerotam and sulfoxaflor prolonged immature development by 2.37 and 1.83 days, respectively, when compared with the control. Male development was slightly shorter than that of female in control, spinetoram, and sulfoxaflor groups, and the opposite was true for the neonicotinoids. Compared to the neonicotinoids, the non-neonicotinoids had more negative effect on juvenile development of E. mundus.

Maternal Piwi regulates primordial germ cell development to ensure the fertility of female progeny in Drosophila.

In many animals, germline development is initiated by proteins and RNAs that are expressed maternally. PIWI proteins and their associated small noncoding PIWI-interacting RNAs (piRNAs), which guide PIWI to target RNAs by base-pairing, are among the maternal components deposited into the germline of the Drosophila early embryo. Piwi has been extensively studied in the adult ovary and testis, where it is required for transposon suppression, germline stem cell self-renewal, and fertility. Consequently, loss of Piwi in the adult ovary using piwi-null alleles or knockdown from early oogenesis results in complete sterility, limiting investigation into possible embryonic functions of maternal Piwi. In this study, we show that the maternal Piwi protein persists in the embryonic germline through gonad coalescence, suggesting that maternal Piwi can regulate germline development beyond early embryogenesis. Using a maternal knockdown strategy, we find that maternal Piwi is required for the fertility and normal gonad morphology of female, but not male, progeny. Following maternal piwi knockdown, transposons were mildly derepressed in the early embryo but were fully repressed in the ovaries of adult progeny. Furthermore, the maternal piRNA pool was diminished, reducing the capacity of the PIWI/piRNA complex to target zygotic genes during embryogenesis. Examination of embryonic germ cell proliferation and ovarian gene expression showed that the germline of female progeny was partially masculinized by maternal piwi knockdown. Our study reveals a novel role for maternal Piwi in the germline development of female progeny and suggests that the PIWI/piRNA pathway is involved in germline sex determination in Drosophila.

AT2R deficiency in mice accelerates podocyte dysfunction in diabetic progeny in a sex-dependent manner.

The angiotensin II receptor type 2 (AT2R) may be a potential therapeutic target for the treatment of hypertension and chronic kidney disease (CKD). The expression and function of AT2R in the vasculature and kidney appear sexually dimorphic. We hypothesised that Agtr2 knockout dams (AT2RKO) with gestational diabetes would program their offspring for subsequent hypertension and CKD in a sex-dependent manner. Age- and sex-matched offspring of non-diabetic and diabetic dams of wild-type (WT) and AT2RKO mice were followed from 4 to 20weeks of age and were monitored for development of hypertension and nephropathy; a mouse podocyte cell line (mPOD) was also studied. Body weight was progressively lower in female compared with male offspring throughout the lifespan. Female but not male offspring from diabetic AT2RKO dams developed insulin resistance. Compared with the offspring of non-diabetic dams, the progeny of diabetic dams had developed more hypertension and nephropathy (apparent glomerulosclerosis with podocyte loss) at 20weeks of age; this programming was more pronounced in the offspring of AT2RKO diabetic dams, particularly female AT2RKO progeny. Female AT2RKO offspring had lower basal ACE2 glomerular expression, resulting in podocyte loss. The aberrant ACE2/ACE ratio was far more diminished in glomeruli of female progeny of diabetic AT2RKO dams than in male progeny. Knock-down of Agtr2 in mPODs confirmed the in vivo data. AT2R deficiency accelerated kidney programming in female progeny of diabetic dams, possibly due to loss of protective effects of ACE2 expression in the kidney.

Early-Pregnancy Dydrogesterone Supplementation Mimicking Luteal-Phase Support in ART Patients Did Not Provoke Major Reproductive Disorders in Pregnant Mice and Their Progeny

Progestogens are frequently administered during early pregnancy to patients undergoing assisted reproductive techniques (ART) to overcome progesterone deficits following ART procedures. Orally administered dydrogesterone (DG) shows equal efficacy to other progestogens with a higher level of patient compliance. However, potential harmful effects of DG on critical pregnancy processes and on the health of the progeny are not yet completely ruled out. We treated pregnant mice with DG in the mode, duration, and doses comparable to ART patients. Subsequently, we studied DG effects on embryo implantation, placental and fetal growth, fetal-maternal circulation, fetal survival, and the uterine immune status. After birth of in utero DG-exposed progeny, we assessed their sex ratios, weight gain, and reproductive performance. Early-pregnancy DG administration did not interfere with placental and fetal development, fetal-maternal circulation, or fetal survival, and provoked only minor changes in the uterine immune compartment. DG-exposed offspring grew normally, were fertile, and showed no reproductive abnormalities with the exception of an altered spermiogram in male progeny. Notably, DG shifted the sex ratio in favor of female progeny. Even though our data may be reassuring for the use of DG in ART patients, the detrimental effects on spermatogenesis in mice warrants further investigations and may be a reason for caution for routine DG supplementation in early pregnancy.

281 Can We Developmentally Program the Epigenome to Improve Traits Relevant to Production in Cattle?

Abstract While sequence variation can be informative to associate regions of the genome with specific traits and improve genetic selection, the epigenome may provide a more powerful tool to manage cattle. Identifying practices that are producer friendly and effectively control epigenetic function within animals is crucial to translating developmental programming to a production setting. Initial studies of developmental programming investigated how environmental or nutritional stresses during fetal and peri-natal development impacted performance of animals later in life. These studies demonstrated changes in methylation, alterations in transcript abundance, and negative impacts on physiology, but they also suggested that we may be able to beneficially impact the epigenome and developmentally program animals to excel in their niche in the production system. Maternal nutritional status during the third trimester influenced date of conception of female progeny in several studies but failed to do so in other studies. Transcriptomic analyses provided evidence that nutritional treatments alter mRNA abundance in brain, liver, muscle, and ovary, but does not conclusively demonstrate that this is due to functional changes in the epigenome. If developmental programming is to be applied in production systems, responses must be consistent and beneficial. Reducing nutrient intake in heifers during peri-pubertal development increased number of primordial follicles in the ovaries and reproductive longevity. While nutritional programming of the ovarian reserve in peri-pubertal heifers appears to occur consistently across locations and studies, it does not ensure that subsequent environmental stressors will not induce changes in the ovarian reserve that will negate beneficial effects. These studies demonstrate that it is possible to developmentally program the epigenome in cattle in ways that will improve production traits; however, there remains a need for studies to improve the consistency of response and to determine best practices that fit into production systems. USDA is an equal opportunity provider and employer.

Long-Term Effects of Late Gestation in Utero Hypoxic Stress on Mood Disorders: Sex and Age Differences

Abstract Introduction: In utero insults have been linked with increased fear and anxiety in progeny. In utero hypoxic stress is associated with a multitude of gestational complications such as pregnancy-associated hypertensive disorders and intrauterine growth restriction. Maternal hypertension during pregnancy is also associated with increased mood and anxiety disorders in progeny. However, it is unknown if these associations are due to in utero hypoxic stress. We hypothesized that exposure to late gestational hypoxia will have a long-term impact on anxiety in progeny. Methods: Timed pregnant female Long-Evans rats were exposed to five days (gestational days: 15-20) of chronic intermittent hypoxia (CIH) or room air (normoxia - 21% O2) for 8 hours during their sleep phase. Each CIH cycle was 6 min of 3 min hypoxia (10% O2) and 3 min normoxia (21% O2) for a total of 10 CIH cycles/hour. At weaning (PND 28), progeny was pair-housed with a conspecific of same sex and similar weight. To examine mood and anxiety disorders, we quantified anxiety-related behaviors (time spent in the center of open field arena, marble burying test, social and anti-social behaviors with conspecifics) along with quantifying food intake and circulating sex hormone levels during puberty (postnatal day, PND 40-45) and young adulthood (PND 60-65) in male and female progeny. Results: Gestational CIH did not impact circulating sex hormones or food intake, regardless of sex or age of progeny. However, gestational CIH increased anxiety related behaviors in pubertal females. These effects of gestational CIH on anxiety in pubertal females were not maintained, as these behaviors resolved in young adulthood. Gestational CIH did not impact male progeny, regardless of age. Conclusion: Exposure to CIH during gestation resulted in increased anxiety related behaviors in pubertal female progeny. In utero hypoxia during late gestation may temporarily increase the risk for mood and anxiety disorders in pubertal females.

Long-Term Effects of Late Gestation in Utero Hypoxic Stress on Neurodegeneration: Sex and Age Differences

Abstract Introduction: In utero insults have been proposed to lead to the onset of neurodegenerative diseases later in life, such as Parkinson’s disease (PD). In utero hypoxia is associated with a multitude of conditions, such as maternal sleep apnea, preeclampsia, gestational diabetes, and maternal hypertension. Exposure to in utero hypoxia may impact male progeny more than female progeny, which may underlie the male biased sex differences in PD. It is currently unknown whether late gestational hypoxic stress has a long-term effect on brain regions associated with PD, such as the nigrostriatal pathway. We hypothesized that exposure to late gestational hypoxia will result in nigrostriatal impairment in adult male progeny compared to adult female progeny. Methods: Timed pregnant female Long-Evans rats were exposed to five days (gestational days: 15-20) of chronic intermittent hypoxia (CIH) or room air (normoxia - 21% O2) for 8 hours during their sleep phase. Each CIH cycle was 6 min of 3 min hypoxia (10% O2) and 3 min normoxia (21% O2) for a total of 10 CIH cycles/hour. Gestational age at delivery was recorded and neonate’s body weights were measured within 12-16 hours from birth. At weaning (postnatal day, PND 28), progeny was pair-housed with a conspecific of the same sex and similar weight. To examine PD, we focused on PD associated characteristics of oxidative stress in the nigrostriatal pathway and behavioral impairments of motor (open field activity and ultrasonic vocalizations) and cognitive (spatial memory) function during puberty (PND 40-45) and young adulthood (PND 60-65). Results: Gestational CIH had no effect on the duration of gestation, litter size, and neonatal weight at birth. Gestational CIH did not impact circulating oxidative stress, regardless of sex or age of progeny. Offspring gross motor function (open field activity) and cognitive (Morris Water maze) function were unaffected by gestational CIH. In contrast, gestational CIH impaired ultrasonic vocalizations in adult male progeny. Gestational CIH increased the latency to vocalize and decreased the loudness of the vocalizations in adult male progeny. Conclusion: Exposure to CIH during gestation resulted in nigrostriatal impairment in adult male progeny, as evidenced by impaired ultrasonic vocalizations that require a functional nigrostriatal pathway. In utero hypoxia during late gestation may increase the risk for PD in males.

Association between the Effects of High Temperature on Fertility and Sleep in Female Intra-Specific Hybrids of Drosophila melanogaster.

Simple SummaryGiven the complexity of the human reproduction system and the numerous limitations imposed on human studies, a fruit fly model was used to investigate whether the effects of high temperature on fertility and sleep correlate one with another. No evidence was provided for a causal link of temperature-sensitive sterility with sleep disturbance under high temperature in infertile females born from females of Canton-S strain and males of Harwich strain. However, sensitivity of sleep of these females to high temperature differed from that in fertile females born from females of Harwich strain and males of Canton-S strain and in males of either cross.Humans and fruit flies demonstrate similarity in sleep-wake behavior, e.g., in the pattern of sleep disturbances caused by an exposure to high temperature. Although research has provided evidence for a clear connection between sleeping problems and infertility in women, very little is known regarding the mechanisms underlying this connection. Studies of dysgenic crosses of fruit flies revealed that an exposure to elevated temperature induces sterility in female intra-specific hybrids exclusively in one of two cross directions (progeny of Canton-S females crossed with Harwich males). Given the complexity and limitations of human studies, this fruit flies’ model of temperature-sensitive sterility might be used for testing whether the effects of high temperature on fertility and on 24-h sleep pattern are inter-related. To document this pattern, 315 hybrids were kept for at least five days in constant darkness at 20 °C and 29 °C. No evidence was found for a causal link between sterility and sleep disturbance. However, a diminished thermal responsiveness of sleep was shown by females with temperature-induced sterility, while significant responses to high temperature were still observed in fertile females obtained by crossing in the opposite direction (i.e., Canton-S males with Harwich females) and in fertile males from either cross.

Fumigant toxicity of essential oils from three lamiaceous plants and methyl iodide against Phthorimaea operculella (zeller) (Lep.: Gelechiidae)

The potato tuberworm, Phthorimaea operculella (Zeller), is a major pest that courses economic losses of potato Solanum tuberosum L. in both the field and the stores. In this research, the fumigant toxicity of essential oils of three Lamiaceous plants including Thymus caucasicus L., Rosmarinus officinalis L. and Satureja hortensis L. and methyl iodide (a chemical fumigant) were evaluated on P. operculella and on its demographic parameters under the laboratory conditions. Essential oils were extracted through hydro-distillation method using a Clevenger-type apparatus. The gas chromatography-mass spectroscopy (GC-MS) analysis indicated that thymol (29.76 %) in T. caucasicus, carvacrol (36.67 %) in S. hortensis and 1, 8-cineole (26.94 %) in R. officinalis essential oils were the major secondary constituents. The 50 % Lethal Concentration (LC50) values for T. caucasicus, R. officinalis, and S. hortensis essential oils as well as methyl iodide towards P. operculella eggs were 5.99, 4.58, 3.55 and 0.29 µL L− 1 air, respectively. On the other hand, methyl iodide showed the highest acute toxicity on the egg stage of P. operculella compared to the essential oils. The 30 % Lethal Concentration (LC30) values of T. caucasicus, R. officinalis, and S. hortensis essential oils and methyl iodide (4.12, 3.53, 1.96, and 0.23 µL L− 1 air, respectively) were affected the life history and demographical parameters of P. operculella. The longest development time was observed on methyl iodide and the shortest was on T. caucasicus and S. hortensis essential oils. The intrinsic rate of natural increase (rm) values obtained in the control group and treated insects were: 0.19, 0.16, 0.14, 0.13, and 0.01 female progenies per female per day for T. caucasicus, S. hortensis, R. officinalis essential oils and methyl iodide, respectively. These results suggested that methyl iodide was significantly more toxic to the P. operculella compared to the essential oils of all the three mentioned plants. Meanwhile, it was concluded that the application of these plant essential oils can be useful as an alternative method for potato tuberworm control in storage facilities.

Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: postweaning responses of offspring reared as replacement heifers or feeder cattle.

One hundred and ninety nonlactating, pregnant beef cows (¾ Bos taurus and ¼ Bos indicus; 138 multiparous and 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (day 0). Cows were ranked by parity, pregnancy type (artificial insemination = 102, natural service = 88), body weight (BW) and body condition score, and assigned to receive a supplement containing: (1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 95) or (2) an organic complexed source of Cu, Mn, Co, and Zn (AAC; Availa4; Zinpro Corporation, Eden Prairie, MN; n = 95). The INR and AAC provided the same daily amount of Cu, Co, Mn, and Zn, based on 7 g of the AAC source. From day 0 to calving, cows were maintained in a single pasture and segregated 3 times weekly into 1 of 24 individual feeding pens to receive treatments. Calves were weaned on day 367 (200 ± 2 d of age), managed as a single group for a 45-d preconditioning period (days 367 to 412), and transferred to a single oat (Avena sativa L.) pasture on day 412. Heifer calves were moved to an adjacent oat pasture on day 437, where they remained until day 620. Heifer puberty status was verified weekly (days 437 to 619) based on plasma progesterone concentrations. Steer calves were shipped to a commercial feedlot on day 493, where they were managed as a single group until slaughter (day 724). Plasma cortisol concentration was greater (P = 0.05) in AAC calves at weaning but tended to be less (P = 0.10) on day 370 compared with INR calves. Mean plasma haptoglobin concentration was greater (P = 0.03) in INR vs. AAC calves during preconditioning, and no treatment effects were noted (P = 0.76) for preconditioning average daily gain (ADG). Puberty attainment was hastened in AAC heifers during the experiment (treatment × day; P < 0.01), despite similar (P = 0.39) ADG between treatments from days 412 to 620. Expression of myogenin mRNA in the longissimus muscle was greater (P = 0.05) in INR vs. AAC heifers on day 584. No treatment effects were detected (P ≥ 0.24) for steer ADG from day 412 until slaughter, nor for carcass quality traits. Hepatic mRNA expression of metallothionein 1A was greater (P = 0.02) in INR vs. AAC steers on day 586. In summary, supplementing Co, Cu, Zn, and Mn as organic complexed instead of sulfate sources to beef cows during the last 5 mo of gestation did not improve performance and physiological responses of the steer progeny until slaughter, but hastened puberty attainment in the female progeny reared as replacement heifers.

Radiation biology and inherited sterility in Helicoverpa armigera Hübner (Lepidoptera: Nuctuidae)

Helicoverpa armigera Hubner (Lepidoptera: Nuctuidae) is a well-known pest in the world which has established itself all over Iran. The effects of different doses of gamma radiation in the range of 100 to 350 Gy on some biological parameters of H. armigera were evaluated. The mean percentage of pupal mortality increased with increasing doses when 8-day-old pupae were irradiated. The lifespan of male and female H. armigera irradiated in the pupal stage were significantly shortened. The number of eggs (fecundity) of the female moths was remarkably affected by irradiation in all crosses. The percentage of hatched eggs (fertility) reached 0 at 350 Gy in various reciprocal crosses, while this value was less than 4 % when normal males mated with irradiated females at 300 Gy. The mean percentage of hatched eggs laid by F1 female progeny markedly decreased when male parents were irradiated at 150 Gy and reached 0 at the dose of 200 Gy in both crosses (F1 males or F1 females mated with non-irradiated partners). The sex ratio of emerged adults of F1 progeny from irradiated male parents skewed to male with increasing doses and reached to 0.66 at 200 Gy.

Effects of yellow peach moth Conogethes punctiferalis egg age on parasitism and oviposition behaviour of four indigenous Trichogramma strains in China

ABSTRACT The yellow peach moth, Conogethes punctiferalis (Guenée) has become a major insect pest in Huang-Huai-Hai summer corn region of China in recent years. Larvae directly threatens the yield and quality of corn by boring into corn ear and feeding. Currently, there are few studies to use the parasitoids, Trichogramma, to control the pest C. punctiferalis, so this study firstly evaluated the parasitism, suitability and oviposition behaviour of Trichogramma on C. punctiferalis eggs at different ages in laboratory. We found that C. punctiferalis eggs at different ages could be parasitised by four Trichogramma strains, but the number of parasitised eggs gradually decreased with egg age. Among them, the Xd strain of T. dendrolimi exhibited a better acceptance to old age eggs, which parasitised 12.8 host eggs within 24 h. The percentage of female progeny of Xd strain was the highest among the four strains when young eggs were provided. Parasitoids took more drilling time on old eggs than that on young ones, however, the Xd strain took 37.07s, 36.60s and 44.27s on young, middle and old eggs, respectively, and with no significant difference. The current study has shown that the Xd strain of T. dendrolimi performed better on the parasitism, the acceptance to old age eggs, the host handing time and the suitability of progeny than other strains, indicating that this strain may be a potential biocontrol agent for C. punctiferalis.

Vector Transmission of Tomato Yellow Leaf Curl Thailand Virus by the Whitefly Bemisia tabaci: Circulative or Propagative?

Simple SummaryTomato yellow leaf curl viruses cause disease epidemics in tomato crops in tropical and subtropical areas worldwide. The sweet potato whitefly, Bemisia tabaci, is a vector of this group of viruses. This research studied the transmission biology of tomato yellow leaf curl Thailand virus (TYLCTHV) by B. tabaci, including virus-infected tissues, virus translocation, virus replication, and transovarial transmission (i.e., transmission from mother to progeny via ovaries). We discovered that the virus first infects the alimentary gut, then the hemolymph, and finally the salivary glands of the whitefly. The virus did not replicate in the whitefly during infection. In addition, TYLCTHV was detected in only 10% of infected females’ first-generation progeny, but the progeny was unable to cause viral infection of tomato plants; therefore, there was no evidence of transovarial transmission. When combined with the current literature, our results suggest that B. tabaci transmits TYLCTHV in a persistent-circulative mode.Viruses that cause tomato yellow leaf curl disease are part of a group of viruses of the genus Begomovirus, family Geminiviridae. Tomato-infecting begomoviruses cause epidemics in tomato crops in tropical, subtropical, and Mediterranean climates, and they are exclusively transmitted by Bemisia tabaci in the field. The objective of the present study was to examine the transmission biology of the tomato yellow leaf curl Thailand virus (TYLCTHV) by B. tabaci, including virus-infected tissues, virus translocation, virus replication, and transovarial transmission. The results demonstrated that the virus translocates from the alimentary gut to the salivary glands via the hemolymph, without apparent replication when acquired by B. tabaci. Furthermore, the virus was detected in 10% of the first-generation progeny of viruliferous females, but the progeny was unable to cause the viral infection of host plants. There was no evidence of transovarial transmission of TYLCTHV in B. tabaci. When combined with the current literature, our results suggest that B. tabaci transmits TYLCTHV in a persistent-circulative mode. The present study enhances our understanding of virus–vector interaction and the transmission biology of TYLCTHV in B. tabaci.

The Impact of Neonatal Methamphetamine on Spatial Learning and Memory in Adult Female Rats.

The present study was aimed at evaluating cognitive changes following neonatal methamphetamine exposure in combination with repeated treatment in adulthood of female Wistar rats. Pregnant dams and their pups were used in this study. One half of the offspring were treated indirectly via the breast milk of injected mothers, and the other half of pups were treated directly by methamphetamine injection. In the group with indirect exposure, mothers received methamphetamine (5 mg/ml/kg) or saline (1 ml/kg) between postnatal days (PD) 1–11. In the group with direct exposure, none of the mothers were treated. Instead, progeny were either: (1) treated with injected methamphetamine (5 mg/ml/kg); or (2) served as controls and received sham injections (no saline, just a needle stick) on PD 1–11. Learning ability and memory consolidation were tested on PD 70–90 in the Morris Water Maze (MWM) using three tests: Place Navigation Test, Probe Test, and Memory Recall Test. Adult female progeny were injected daily, after completion of the last trial of MWM tests, with saline or methamphetamine (1 mg/ml/kg). The effects of indirect/direct neonatal methamphetamine exposure combined with acute adult methamphetamine treatment on cognitive functions in female rats were compared. Statistical analyses showed that neonatal drug exposure worsened spatial learning and the ability to remember the position of a hidden platform. The study also demonstrated that direct methamphetamine exposure has a more significant impact on learning and memory than indirect exposure. The acute dose of the drug did not produce any changes in cognitive ability. Analyses of search strategies (thigmotaxis, scanning) used by females during the Place Navigation Test and Memory Recall Test confirmed all these results. Results from the present study suggested extensive deficits in learning skills and memory of female rats that may be linked to the negative impact of neonatal methamphetamine exposure.

Western Kenyan Anopheles gambiae showing intense permethrin resistance harbour distinct microbiota

BackgroundInsecticide resistance poses a growing challenge to malaria vector control in Kenya and around the world. Following evidence of associations between the mosquito microbiota and insecticide resistance, the microbiota of Anopheles gambiae sensu stricto (s.s.) from Tulukuyi village, Bungoma, Kenya, with differing permethrin resistance profiles were comparatively characterized.MethodsUsing the CDC bottle bioassay, 133 2–3 day-old, virgin, non-blood fed female F1 progeny of field-caught An. gambiae s.s. were exposed to five times (107.5 µg/ml) the discriminating dose of permethrin. Post bioassay, 50 resistant and 50 susceptible mosquitoes were subsequently screened for kdr East and West mutations, and individually processed for microbial analysis using high throughput sequencing targeting the universal bacterial and archaeal 16S rRNA gene.Results47 % of the samples tested (n = 133) were resistant, and of the 100 selected for further processing, 99 % were positive for kdr East and 1 % for kdr West. Overall, 84 bacterial taxa were detected across all mosquito samples, with 36 of these shared between resistant and susceptible mosquitoes. A total of 20 bacterial taxa were unique to the resistant mosquitoes and 28 were unique to the susceptible mosquitoes. There were significant differences in bacterial composition between resistant and susceptible individuals (PERMANOVA, pseudo-F = 2.33, P = 0.001), with presence of Sphingobacterium, Lysinibacillus and Streptococcus (all known pyrethroid-degrading taxa), and the radiotolerant Rubrobacter, being significantly associated with resistant mosquitoes. On the other hand, the presence of Myxococcus, was significantly associated with susceptible mosquitoes.ConclusionsThis is the first report of distinct microbiota in An. gambiae s.s. associated with intense pyrethroid resistance. The findings highlight differentially abundant bacterial taxa between resistant and susceptible mosquitoes, and further suggest a microbe-mediated mechanism of insecticide resistance in mosquitoes. These results also indicate fixation of the kdr East mutation in this mosquito population, precluding further analysis of its associations with the mosquito microbiota, but presenting the hypothesis that any microbe-mediated mechanism of insecticide resistance would be likely of a metabolic nature. Overall, this study lays initial groundwork for understanding microbe-mediated mechanisms of insecticide resistance in African mosquito vectors of malaria, and potentially identifying novel microbial markers of insecticide resistance that could supplement existing vector surveillance tools.