RFRP3 influences basal lamina degradation, cellular death, and progesterone secretion in cultured preantral ovarian follicles from the domestic cat.

The hypothalamic neuropeptide RFRP3 can suppress hypothalamic GnRH neuron activation and inhibit gonadotropin release from the anterior pituitary. RFRP3 is also produced locally in the ovary and can inhibit steroidogenesis and follicle development in many vertebrates. However, almost nothing is known about the presence and regulatory action of RFRP3 in gonads of any carnivore species. Such knowledge is important for developing captive breeding programs for endangered carnivores and for inhibiting reproduction in feral species. Using the domestic cat as a model, our objectives were to (1) demonstrate the expression of feline RFRP3 (fRFRP3) and its receptor in the cat ovary and (2) assess the influence of fRFRP3 on ovarian follicle integrity, survival, and steroidogenesis in vitro. We first confirmed that fRFRP3 and its receptors (NPFFR1 and NPFFR2) were expressed in cat ovaries by sequencing PCR products from ovarian RNA. We then isolated and cultured preantral ovarian follicles in the presence of 10 or 1 µM fRFRP3 + FSH (1 µg/mL). We recorded the percentage of morphologically viable follicles (basal lamina integrity) over 8 days and calculated percentage survival of follicles on Day 8 (using fluorescent markers for cell survival and death). Last, we quantified progesterone accumulation in media. 10 µM fRFRP3 had no observable effect on viability, survival, or steroid production compared to follicles exposed to only FSH. However, 1 µM fRFRP3 decreased the percentage of morphologically viable follicles and the percentage of surviving follicles on Day 8. At the same time, 1 µM fRFRP3 increased the accumulation of progesterone in media. Our study shows, for the first time, direct action of RFRP3 on the follicle as a functional unit, and it is the first in a carnivore species. More broadly, our results support a conserved, inhibitory action of RFRP3 on ovarian follicle development and underscore the importance of comparative functional studies

The direct response of the gonads to cues of stress in a temperate songbird species is season-dependent.

The gonadotropin releasing hormone (GnRH) system in the hypothalamus is often considered the final point in integration of environmental cues as they pertain to the reproductive axis. However, cues such as stress and food availability are detectable in the plasma (as glucocorticoid and metabolic fuel fluctuations). Vertebrate gonads express glucocorticoid receptor, therefore we hypothesized that the gonads can detect and respond directly to cues of stress. We provide evidence here that, in addition to regulation by the brain, the gonads of European starlings (Sturnus vulgaris) respond directly to fluctuations in corticosterone and metabolic fuels by modulating sex steroid secretion. Using a 4-h gonad culture, we show that physiologically-relevant concentrations of corticosterone and metabolic stress (via use of the glucose utilization inhibitor 2-deoxy-D-glucose and the fatty acid oxidation inhibitor ethyl 2-mercaptoacetate (2DG/MA)) can directly decrease testosterone and estradiol secretion from luteinizing hormone and follicle-stimulating hormone (LH/FSH)-stimulated testes and ovaries. This effect is regulated seasonally. Prior to the breeding season, testes and ovaries respond to corticosterone and 2DG/MA by significantly decreasing gonadal steroid release. Within the breeding season, the testes do not respond to these cues of stress, while the ovaries respond only to corticosterone. This seasonal difference in response may be due in part to the influence of these cues of stress on gonadal neuropeptide expression: corticosterone upregulates GnIH expression in the testes while metabolic stress upregulates GnIH in the ovaries. Thus the gonads can directly respond to fluctuations in corticosterone and metabolic fuels during a time of critical importance to the onset of breeding

Neuropeptides in the Gonads: From Evolution to Pharmacology

Vertebrate gonads are the sites of synthesis and binding of many peptides that were initially classified as neuropeptides. These gonadal neuropeptide systems are neither well understood in isolation, nor in their interactions with other neuropeptide systems. Further, our knowledge of the control of these gonadal neuropeptides by peripheral hormones that bind to the gonads, and which themselves are under regulation by true neuropeptide systems from the hypothalamus, is relatively meager. This review discusses the existence of a variety of neuropeptides and their receptors which have been discovered in vertebrate gonads, and the possible way in which such systems could have evolved. We then focus on two key neuropeptides for regulation of the hypothalamo-pituitary-gonadal axis: gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH). Comparative studies have provided us with a degree of understanding as to how a gonadal GnRH system might have evolved, and they have been responsible for the discovery of GnIH and its gonadal counterpart. We attempt to highlight what is known about these two key gonadal neuropeptides, how their actions differ from their hypothalamic counterparts, and how we might learn from comparative studies of them and other gonadal neuropeptides in terms of pharmacology, reproductive physiology and evolutionary biology

Towards a More Comprehensive View of the Use of Power Between Couple Members in Adolescent Romantic Relationships

This study investigated the construct of power in adolescent romantic couples using multiple measures. The project examined gender differences in power, created models of powerlessness for each gender, and examined relations between power and aggression and relationship quality. Participants were 90 heterosexual couples, aged 14-18 years old, living in rural areas in Utah and Arizona. Couple members completed surveys assessing attitudes and behaviors in their relationships and a video-recall procedure in which partners rated their own and their partner\u27s behaviors during problem solving discussion. Few gender differences emerged in reports of perpetration of aggression, but boyfriends reported higher levels of emotional vulnerability and lower levels of resource control for several power-related outcomes. Structural equation modeling yielded models that appeared to capture the construct of powerlessness, with different models emerging for boyfriends and girlfriends. Finally, stepwise regressions revealed strong associations between measures of power and relationship outcomes with interesting gender differences

Does Empathic Accuracy Mediate the Relationships Between Individual Psychological Characteristics and Adolescent Romantic Relationship Functioning?

This study investigated empathic accuracy in adolescent romantic relationships. The project examined the relationships between psychological characteristics and relationship outcomes (i.e., satisfaction and aggression) to determine if the relationships were mediated by empathic accuracy. Participants were 92 heterosexual couples aged 14-18 years old who lived in rural areas in Utah and Arizona. Couple members completed surveys assessing attitudes and behaviors in their relationships and a video-recall procedure in which partners rated their own and their partner\u27s behaviors during problem-solving discussion. Empathic accuracy was generally not related to psychological characteristics or outcomes. It became apparent that there were limitations with the methodology used to measure empathic accuracy. Due to the very strong correlations between participants\u27 ratings of themselves and their ratings of their partners, ratings of self and partner were collapsed for each interaction variable to capture interpretations/biases employed by the participants in evaluating aspects of their interactions. The global video-recall ratings were then analyzed to determine if they mediated the relationships between psychological characteristics and outcomes. Rejection sensitivity emerged as an important psychological characteristic, and interpretations of conflict and sarcasm mediated the relationship between rejection sensitivity and outcomes of aggression and satisfaction

The Role of RFamide-Related Peptide-3 in Age-Related Reproductive Decline in Female Rats.

Reproductive senescence, the point in time when females cease to show estrous cyclicity, is associated with endocrine changes in the hypothalamus, pituitary, and gonads. However, the mechanisms triggering this transition are not well understood. To gain a better understanding of the top-down control of the transition from reproductive competence to a state of reproductive senescence, we investigated middle-aged female rats exhibiting varying degrees of reproductive decline, including individuals with normal cycles, irregular cycles, and complete cessation of cycles. We identified hormonal changes in the brain that manifest before ovarian cycles exhibit any deterioration. We found that females exhibit an increase in RFamide-related peptide-3 (RFRP3) mRNA expression in the hypothalamus in middle age prior to changes in estrous cycle length. This increase is transient and followed by subsequent decreases in kisspeptin (KiSS1) and gonadotropin-releasing hormone (GnRH) mRNA expression. Expression of RFRP3 and its receptor also increased locally in the ovaries with advancing age. While it is well known that aging is associated with decreased GnRH release and downstream disruption of the hypothalamic-pituitary-gonadal (HPG) axis, herein, we provide evidence that reproductive senescence is likely triggered by alterations in a network of regulatory neuropeptides upstream of the GnRH system

Neurosecretory Protein GL Induces Fat Accumulation in Chicks.

We recently found a previously unidentified cDNA in chicken hypothalamus which encodes the precursor for neurosecretory protein GL (NPGL). A previous study showed that intracerebroventricular (i.c.v.) infusion of NPGL caused body mass gain in chicks. However, it was not clear which part(s) of the body gained mass. In the present study, we investigated which tissues increased in mass after chronic i.c.v. infusion of NPGL in chicks. We found that NPGL increased the masses of the liver, abdominal fat, and subcutaneous fat, while NPGL did not affect the masses of muscles, including pectoralis major, pectoralis minor, and biceps femoris. Oil Red O staining revealed that fat deposition had occurred in the liver. In addition, the size of the lipid droplets in the abdominal fat increased. Furthermore, we found an upregulation of lipogenesis and downregulation of lipolysis in the abdominal fat, but not in the liver. These results indicate that NPGL is involved in fat storage in chicks

View of the Capitol at Washington

The the hand-colored steel engraving features an outdoor scene in front of the United States Capitol. In the foreground, carriages and groups of people are shown along a road leading to the Capitol. Various trees and buildings line the road. At the center of the background, the Capitol building is depicted. The engraving originally appeared in a publication by N.P. Willis\u27s American Scenery. This particular copy was enclosed in a wooden frame sealed with masking tape but was removed for preservation.https://scholarsjunction.msstate.edu/fvw-prints/1064/thumbnail.jp

The biological control of the weed Acacia longifolia by the gall wasp Trichilogaster acaciaelongfoliae: a study of a plant-insect interaction

Weeds are responsible for about 30 percent of all crop losses worldwide, but all weed research, including biological control, receives only about 10% of crop pest control support. The impact of weeds is insidious, diffuse, and complex Increased use of biological control may help to reduce the massive quantity of energy and time now expended for weed control worldwide. Batra (1981) "The vitality of biocontrol of weeds requires two types of evaluation before a project is completed. To maintain financial support it is necessary to show that biocontrol is an economical method of solving certain types of weed problems and to improve the effectiveness of biocontrol in the future, it is necessary to have scientific feed-back. Essentially, the first type of evaluation is concerned with what has been achieved and the second with why the result, either success or failure, has been achieved." Harris (1980a) The biological control of weeds using insects is a young science. The first intentional use of an insect to control a weed was in 1863 in India where the cochineal insect, Dactylopius ceylonicus (Green), was dispersed to control Opuntia vulgaris Miller some 68 years after the accidental introduction of this insect to that country (Goeden, 1978; Moran & Zimmermann, 1984). However, the first full scale attempt at a classical weed biocontrol programme was against Lantana camara L. in Hawaii in 1902 (Goeden, 1978; Harley, 1985a). By 1984 there had been 499 releases of exotic invertebrates and fungi, 488 of which were insects, for the control of 101 weed species in 70 countries (Julien et al., 1984). Despite this marked increase in the number of biocontrol programmes in later years, attempts which failed have rarely been studied or documented and even successes are seldom adequately quantified. This has been implied by Harley (1985a), Julien, (1982), Julien et al. (1984) and Maw (1984). The pressure to produce results and the difficulty of determining the reasons for failures are prohibitive (Dennill et al., 1987; Appendix 6; Goeden & Louda, 1976). The advancement of this science thus relies heavily on the study of its successes. This thesis is an evaluation of the gall wasp Trichilogaster acaciaelongifoliae as a biocontrol agent for the weed Acacia longifolia in South Africa. The wasp has been successful, and, in accordance with Harris (1980a), my aims were twofold: to quantify that success and to provide reasons for it. This information not only produces guidelines ii for the future selection of biocontrol agents, sensu Harris (1980a), but also serves as a means of enhancing our understanding of insect-plant relationships. In addition, this thesis provides an indication of the potential of gall forming insects in biological control of weeds. Gall formers have seldom been used to control weeds (Julien, 1982; Maw, 1984). Since their effects are indirect compared with those of insects attacking vegetative plant parts, their potential for weed biocontrol has apparently been underestimated in the past by some authors (Goeden, 1983; Harris, 1973; Hokkanen, 1985a). The present attempt is the first ever in which a gall forming hymenopteran has been used to control a weed, and shows beyond doubt that certain gall formers can have strong potential in this field. Chapter 1 concerns the establishment of the wasp, its population increases, dispersal, host-seeking, and the reduction of reproductive potential of A. longifolia populations. The development of new techniques that were necessary for the determination of these parameters is included. Emphasis is placed on the reasons for the successful establishment and rapid population increases observed. The potential of the insect for suppressing both reproduction and growth of the weed is great, and is examined in detail in Chapter 2. The phenological information obtained during the course of this study showed important inadequacies in the knowledge of the phenology of A. longifolia. This is rectified in Chapter 3 in which the implications of an incomplete understanding of weed phenology for biological control are emphasised. In particular, the resource allocation between reproduction and growth of the plant provides a crucial setting for the next chapter. In Chapter 4 the nature of the galling by T. acaciaelongifoliae and its relation to the phenology of A. longifolia are examined in order to explain how the wasp is able to exploit its host so effectively under South African conditions. Chapter 5 deals with the release of the wasp throughout the South African range of the weed and the identification of regions in which its performance appears inadequate. The climates of South Africa and Australia are compared to determine to what degree the establishment of T. acaciaelongifoliae in various regions in South Africa is related to the climate of the regions in which the wasp was collected in Australia. This chapter includes maps illustrating weed distribution, co-ordinates for all release points, and documents the method whereby the wasps were released. Chapter 6 is an essay dealing with the implications of the study, both practical and theoretical. Recommendations regarding the future selection of biocontrol agents are made, with emphasis on perspectives emerging from this thesis, and the future role of the wasp in the control of A. longifolia in South Africa is discussed