Methoprene, a juvenile hormone analogue, modifies maturation and emergence in overwintering Osmia rufa L. adults

The development of methods aimed at activation of imagos at any point of wintering provides a compelling potential avenue to utilize bees for pollination of greenhouse crops during autumn, winter, and early spring. In this study, we tested methoprene, a juvenile hormone (JH) analogue as a chemical stimulant to end a diapause of Osmia rufa L. and enable bee activation and emergence under experimental conditions. The application of methoprene significantly reduced the emergence time of adult bees in winter months as compared to vehicle (acetone) and negative controls. Bees treated with methoprene started to emerge 3–6 days earlier than bees from acetone and control groups and finished emergence 2–6 days earlier too. Statistically significant differences were observed between methoprene and controls groups of male and female in all tested incubation periods. It was also observed that the effects of methoprene were significantly more effective in female specimens during the first 2 months of winter. Moreover, in females, methoprene improved reproductive traits such as an increase in the size of terminal oocytes. Similarly, in males, methoprene treatment resulted in a significant increase in a seminal vesicle size and dynamic elevation of spermatozoa number. Taken together, our results indicate that methoprene may play an important role in the termination of diapause, bee activation, and emergence.

Predatory Abilities of The Backswimmer Buenoa Amnigenus Are Not Impaired After Sublethal Exposures To Pyriproxyfen

Pyriproxyfen is a juvenile hormone analogue that is commonly used to control the immature stages of mosquitoes in both artificial and natural water reservoirs. Recently, concerns have been raised regarding the pyriproxyfen community effectiveness in preventing vector-transmitted diseases. Such concerns have been based on the unintended effects on non-target organisms and selection of resistant mosquito populations. Thus, this investigation was conducted aiming to evaluate the toxicity of pyriproxyfen to Aedes aegypti (Diptera: Culicidae) larvae and the backswimmer Buenoa amnigenus (Hemiptera: Notonectidae), a naturally occurring mosquito larvae predator. We also assessed the abilities of backswimmers exposed to sublethal levels of pyriproxyfen to prey upon mosquito larvae (L2) under three larval densities (3, 6, or 9 larvae/100 mL of water) using artificial containers. Our results revealed that pyriproxyfen killed backswimmers only at concentrations higher than 100 mg active ingredient [a.i.]/L, which is 10 times higher than that recommended for larvicidal field application (i.e, 10 mg a.i./L). Interestingly, the abilities of backswimmers exposed to sublethal levels of pyriproxyfen (100 mg a.i./L) to prey upon mosquito larvae were not affected. Harmful effects on the backswimmer predatory abilities were detected only at concentrations of 150 mg a.i./L and when there was a higher prey availability (i.e., 9 larvae/100 mL of water). Together, our findings indicate that the reduced community effectiveness of this insecticide derives from factors other than its detrimental effects on non-target organisms such as the backswimmers.

Gonadotropin releasing hormone analogue treatment of central precocious puberty is not associated with altered prevalence of polycystic ovary syndrome: a single center cohort study

Background There is conflicting evidence regarding an association between gonadotropin releasing hormone analogue (GnRHa) therapy and polycystic ovary syndrome (PCOS). This study aimed to compare the prevalence of endocrine disorders, primarily PCOS, between women who had been treated with GnRHa for central precocious puberty (CPP) and those who were not treated. Methods This was a retrospective cohort study, including women diagnosed with central precocious puberty between 1989 and 2011 in a university affiliated tertiary medical center. Data collected included demographic data, medical background, clinical presentation at diagnosis and duration of treatment (zero for non-treated). Gynecologic and endocrine long-term outcomes were compared by treatment group. Results Fifty-one women were included in the study, 27/51 had been treated with gonadotropin releasing hormone analogue (GnRHa). Overall prevalence of PCOS was 19.6%. No statistically significant difference in prevalence of PCOS was demonstrated between the treated and non-treated groups. Similarly, overall prevalence of either clinical or laboratory hyper-androgenism, was 29.4% and 33.3%, for the treatment and non-treatment groups respectively (p = non-significant). Conclusions GnRHa treatment for precocious puberty is not associated with increased risk of polycystic ovary syndrome.

Sublethal Concentration of Pyriproxyfen Reduces Testicular Connective Tissue Thickness in Euschistus heros Fabr. (Hemiptera: Pentatomidae)

The aim of this study was to determine the effect of the insecticide pyriproxyfen (Tiger™ 100 CE), juvenile hormone analogue, when applied in a sublethal LC30 concentration (0.668 mL a. i. L-1), on the morphological and morphometric parameters of external and internal connective tissue (CT) of the Neotropical-brown stink bug Euschistus heros testicles. The insecticide was applied on nymphs from the 4th instar using a Potter tower with a working pressure of 82.73 kPa (12 lb pol-²) and 1 mL of the emulsion per replicate. A completely randomized experimental design was used, consisting of two treatments (control and pyriproxyfen-treated), five repetitions, and 10 adults of E. heros per experimental unit. The insects were maintained under controlled conditions until the emergence of adults. After 48 h of emergence of adults, the testicles were collected, fixed, and processed for morphological and morphometric analyses. A change was observed in the collagen fibers of the CT of treated insects when compared with those of controls. It was also observed that both types of CT (dense irregular and loose) over the internal tunic of the treated insect were thinner than those in control insects. The analysis showed that pyriproxyfen significantly reduced the external and internal CT width and the conformation of its fibers in all the observed regions when compared with the controls; this may affect the production of the three different types of sperm present in this species.

Efficacy of poly (lactic-co-glycolic acid) microparticles as a gonadotropin-releasing hormone analogue delivery system to stimulate ovulation of peled Coregonus peled

The aim of the study was to determine the efficacy of poly (lactic-co-glycolic acid) microparticles as a carrier of gonadotropin-releasing hormone analogues (GnRHa) for induction of ovulation in peled Coregonus peled. Female peled were injected intraperitoneally with 1) saline solution only (control), 2) mammalian GnRHa at 25 µg/kg body weight, 3) GnRHa in 753-type microparticles at 50 µg/kg, or 4) GnRHa in 653-type microparticles at 50 µg/kg. Blood plasma samples were taken on days 0, 4, 8, and 12 post-injection. All hormone treatments induced synchronous ovulation and higher cumulative ovulation compared to controls. Hormone treatments did not affect relative fecundity or the percentage of eyed eggs. Testosterone level decreased toward the onset of ovulation. On day eight of the trial, the testosterone level was significantly lower in hormone-treated groups compared to the control group. The level of 17β-oestradiol showed a decreasing trend post-injection, with the lowest observed level on day eight. Our results demonstrate that ovulation can be induced in the peled by the sustained – release of GnRHa in poly (lactic-co-glycolic acid) microparticles, but the treatment does not improve reproductive performance.

Artificial propagation and embryonic growth in Stinging catfish, Heteropneustes fossilis (Bloch, 1794) using S-GnRHa (salmon gonadotropin releasing hormone analogue)

An experiment was performed to observe the potentiality of synthetic hormone analogue in artificial propagation i.e., the embryonic and larval development of Heteropneustes fossilis. Broodfish were injected with S-GnRHa according to the following concentration: 1, 2.5 and 5 ml kg-1 of body weight (BW) to females and 0.5, 1.125 and 2.5 ml kg-1 BW to males, in treatment groups T1, T2 and T3, respectively each with three replicates. The fishes were ovulated at about 10-11 hours after the hormone injection. Result showed the highest fertilization (83.11±1.36) and hatching rate (89.56±1.04) in T2, whereas ovulation rate was 100% in all treatment groups. First cleavage was observed in 30 minutes of post-fertilization. Embryonic developmental period sequentially for 2-cell, 4-cell, 8-cell, 16-cell, 32-cell, 64-cell, Morula, Blastula, Gastrula, somatic formation, yolk-plug, twisting movement and pre-hatching were 00:30, 00:45, 01:10, 01:30, 02:00, 02:30, 03:00, 04:00, 06:40, 09:00-18:00, 19:00, 20:00-21:00 and 22:00 hours, respectively. Hatching occurred after 23:00 hours of fertilization. Finally, the current result suggested that S-GnRHa might be an effective synthetic hormone in artificial propagation of H. fossilis.

Chemically-Modified Tetraiodothyroacetic Acid (Tetrac) Induces Cancer Cell Apoptosis and Facilitates Clearance of Apoptotic Debris (Efferocytosis)

Tetraiodothyroaetic acid (tetrac) is a derivative of L-thyroxine with anticancer properties. By multiple molecular mechanisms, tetrac and chemically-modified tetrac induce apoptosis in a variety of human cancer cells in vitro and in xenografts. The anticancer activities of tetrac are initiated at the thyroid hormone analogue receptor on the extracellular domain of plasma membrane integrin αvβ3 (PJ Davis et al., Physiol Rev 101:319-352, 2021). Induction of apoptosis in glioblastoma xenograft with chemically modified tetrac (P-bi-TAT) has yielded 90% in volume of grafts that continues after discontinuation of tetrac. In the present study, we show that human glioblastoma xenograft shrinkage in response to P-bi-TAT is associated with local appearance of phagocytic monocytes and clearance of apoptotic debris (efferocytosis). Primary culture xenograft of glioblastoma cells (GBM 052814, kindly provided by the University of Pittsburgh Medical Center, Department of Neurosurgery) and U87-luc (ATCC, Manassas, VA) xenografts were generated in 5-member groups of nude mice for each tumor cell type and for controls. Five days post-implantation, injection of animals was begun with PBS (control) or P-bi-TAT (10 mg/kg body weight). Injection was continued X21 days and animals were then maintained off-treatment for an additional 21 days. Tumors were harvested, formalin-fixed and slide-mounted, then analyzed by TUNEL assay for apoptosis and by anti-CD68 staining for monocytic macrophage content. Histologic analysis (H&E staining) was also carried out. TUNEL analysis and histopathology of both xenograft models revealed more than 90% apoptotic change with 21-days of P-bi-TAT treatment (P <0.001) and persistence of 40% apoptotic change 3 weeks post-discontinuation of drug (P<0.001 vs. end of treatment change). By H&E histology and CD68 analysis, monocytes accounted for more than 90% of the viable cells after 3 weeks’ drug treatment. Sixty percent of the end-of-treatment monocyte population persisted 3 weeks after discontinuation of P-bi-TAT (P <0.001). Histology revealed negligible cell debris after 3 weeks of drug treatment and at 3 weeks post-discontinuation of P-bi-TAT. Thus, the anticancer/pro-apoptotic action of tetrac-containing P-bi-TAT is associated with efferocytosis that contributes to the frank tumor shrinkage that results from P-bi-TAT treatment of human glioblastoma xenografts. This is the first documentation of efferocytosis regulated from the thyroid hormone analogue receptor on tumor cell integrin αvβ3.

Evaluation of the Binding Affinity of a Gonadotropin-Releasing Hormone Analogue (GnRH-a) Buserelin through In Silico and In Vivo testing in Clarias magur

Aim: To evaluate the binding affinity and biological potency of gonadotropin releasing hormone analogue (GnRHa) Buserelin (‎C60H86N16O13) based on in silico and in vivo testing for induced breeding in Clarias magur. Background: Many attempts have been made to induce C. magur but encouraging results have not yet been achieved. Hence, it is the need of the hour to find out more potent analogues or other bio-molecules for induced breeding in C. magur to facilitate sustainable aquaculture. Objective: To determine the binding affinity of C. magur GnRH receptor through in silico and its validation for induced breeding of C. magur. Methods: Buserelin (‎C60H86N16O13) was selected as the potential GnRHa after screening several peptides for their binding energy with the C. magur GnRH receptor. The induced breeding trial was set up at ICAR-CIFE Powarkheda Centre, M.P. India, and Buserelin was administered in different doses to the brooders along with the dopamine inhibitor domperidone. The standard treatment with the commercial salmon GnRH (sGnRH) analogue Ovaprim® (Syndel, USA) was used as the control. Results: The 3-D structure of C. magur GnRH receptor was generated using MODELLER software. Molecular docking studies revealed the binding preference of the receptor as chicken (c) GnRH-II > Buserelin > sGnRH > catfish (cf) GnRH > human (m) GnRH. Though Buserelin showed better binding affinity compared to sGnRH, induced breeding experiments with magur showed similar performance of the ligands at the equivalent dose of 20 µg/kg B.W., but the spontaneous release of milt from the males was not obsereved in both the cases. Significantly better reproductive parameters were recorded with Buserelin at the dose of 30 µg/kg B.W. Conclusion: The study revealed that that the GnRHa Buserelin can be used as an effective inducing agent for breeding in C. magur.