Reproductive Disruption Research Articles

COVID-19 and Reproductive Function: A Detailed Review of Fertility Outcomes, Sperm Alterations, and Vertical Transmission Concerns

Background:The global COVID-19 pandemic, caused by SARS-CoV-2, raises concerns about its effects on reproductive health. Emerging evidence suggests potential impacts on male and female fertility, including hormonal changes, immune responses, and organ damage, though the virus’s direct influence on reproductive tissues and vertical transmission remains unclear. Objective:This review summarizes current evidence on COVID-19’s effects on male and female reproductive health, focusing on sperm count, fertility, and vertical transmission. Methods:A comprehensive literature review was conducted using databases such as PubMed, Scopus, and Web of Science. Peer-reviewed studies were included based on their relevance to reproductive outcomes, sperm count, hormonal changes, and vertical transmission of SARS-CoV-2. Results:Most studies found no direct evidence of SARS-CoV-2 in male or female reproductive tissues. However, a temporary decline in sperm count and quality has been reported in men recovering from COVID-19. Hormonal fluctuations, particularly increased luteinizing hormone (LH) levels, were observed in some male patients. In females, the presence of ACE2 receptors in reproductive organs suggests a potential risk, but no conclusive evidence of impaired fertility has been found. Vertical transmission remains uncertain, with isolated cases reporting elevated IgM antibodies in newborns. Conclusion:Although direct evidence of SARS-CoV-2 impacting fertility is limited, temporary reproductive disruptions in males, including reduced sperm count, have been noted. The risk of vertical transmission remains unclear. Further research is essential to determine COVID-19’s long-term reproductive effects.

Oxidative Stress-induced Hormonal Disruption in Male Reproduction.

Research into the impacts of oxidative stress (OS), and hormonal balance on reproductive potential has increased over the last 40 years possibly due to rising male infertility. Decreased antioxidant levels and increased OS in tissues result from hormonal imbalance, which in turn leads to male infertility. Increased reactive oxygen species (ROS) generation in seminal plasma has been linked to many lifestyle factors such as alcohol and tobacco use, toxicant exposure, obesity, varicocele, stress, and aging. This article provides an overview of the crosslink between OS and gonadal hormone disruption, as well as a potential mode of action in male infertility. Disrupting the equilibrium between ROS generation and the antioxidant defense mechanism in the male reproductive system may affect key hormonal regulators of male reproductive activities. Unchecked ROS production may cause direct injury on reproductive tissues or could disrupt normal regulatory mechanisms of the hypothalamic-pituitary-gonadal (HPG) axis and its interaction with other endocrine axes, both of which have negative effects on male reproductive health and can lead to male infertility.

Effects of the organochlorine pesticide metabolite p,p’-DDE on the gastrointestinal lipidome in fish: A novel toxicity pathway for a legacy pollutant

Though phased out from use in the United States, environmental contamination by organochlorine pesticides (OCPs) remains a widespread issue, especially around intensive agricultural regions. OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its primary metabolite, dichlorodiphenyldichloroethylene (DDE), have been detected in soils, sediments, surface waters, and biota decades after their discontinued use. As OCPs are persistent and can bioaccumulate in fats, these compounds can transfer and magnify across food webs. Freshwater predatory fish and birds can accumulate high OCP concentrations, leading to a myriad of deleterious impacts on organismal health. Studies have found evidence of reproductive disruption in predatory fish, such as the largemouth bass (LMB; Micropterus salmoides), associated with DDT and DDE exposure. DDE can act through estrogenic pathways and induce the expression of estrogenic signals in male animals; however, the molecular mechanism of disruption is unclear. Recently, metabolomics research has revealed corollary relationships between lipid signals and organic pollutant toxicity. Here, a two-month feeding experiment on LMB was conducted to assess the interactions of DDE (as p,p'-DDE) in food with gut and liver lipid signaling. Targeted lipidomic analysis revealed global alterations in the abundance of tissue lipids, especially cholesteryl esters and phospholipids, in LMB exposed to low levels of p,p'-DDE. Results from these studies indicate that p,p'-DDE may act through disruption of normal lipid homeostasis to cause toxicity in freshwater fish.

P22-08 Reproductive disruption in male fathead minnow exposed to PFAS-contaminated groundwater at a legacy fire-training area

P22-08 Reproductive disruption in male fathead minnow exposed to PFAS-contaminated groundwater at a legacy fire-training area

Environmentally relevant concentrations of the tricyclic antidepressant, amitriptyline, affect feeding and reproduction in a freshwater mollusc

Antidepressant drugs (ADDs) are one of the most extensively used pharmaceuticals globally. They act at particularly low therapeutic concentrations to modulate monoamine neurotransmission, which is one of the most evolutionary conserved pathways in both humans and animal species including invertebrates. As ADDs are widely detected in the aquatic environment at low concentrations (ng/L to low µg/L), their potential to exert drug-target mediated effects in aquatic species has raised serious concerns. Amitriptyline (AMI) is the most widely used tricyclic ADD, while monoamines, the target of ADDs, are major bioregulators of multiple key physiological processes including feeding, reproduction and behaviour in molluscs. However, the effects of AMI on feeding, reproduction and mating behaviour are unknown in molluscs despite their ecological importance, diversity and reported sensitivity to ADDs. To address this knowledge gap, we investigated the effects of environmentally relevant concentrations of AMI (0, 10, 100, 500 and 1000 ng/L) on feeding, reproduction and key locomotor behaviours, including mating, in the freshwater gastropod, Biomphalaria glabrata over a period of 28 days. To further provide insight into the sensitivity of molluscs to ADDs, AMI concentrations (exposure water and hemolymph) were determined using a novel extraction method. The Fish Plasma Model (FPM), a critical tool for prioritization assessment of pharmaceuticals with potential to cause drug target-mediated effects in fish, was then evaluated for its applicability to molluscs for the first time. Disruption of food intake (1000 ng/L) and reproductive output (500 and 1000 ng/L) were observed at particularly low hemolymph levels of AMI, whereas locomotor behaviours were unaffected. Importantly, the predicted hemolymph levels of AMI using the FPM agreed closely with the measured levels. The findings suggest that hemolymph levels of AMI may be a useful indicator of feeding and reproductive disruptions in wild population of freshwater gastropods, and confirm the applicability of the FPM to molluscs for comparative pharmaceutical hazard identification.

Environmentally relevant estrogens impaired spermatogenesis and sexual behaviors in male and female zebrafish

Environmental estrogens (EEs) are found extensively in natural waters and negatively affect fish reproduction. Research on the reproductive toxicity of EEs mixtures in fish at environmentally relevant concentrations is scarce. In this study, adult male zebrafish were exposed for 60 days to EES (a mixture of EEs), EE2-low (5.55 ng/L, with an estrogenic potency equal to EES), and EE2-high (11.1 ng/L). After exposure, the expression levels of vtg1, vtg3, and esr1 in the livers in EES-treated fish remained unaltered, whereas they were significantly increased in EE2-treated fish. Both EE2-high and EES exposures notably reduced the gonad somatic index and sperm count. A disrupted spermatogenesis was also observed in the testes of EE2-high- and EES-exposed fish, along with an alteration in the expression of genes associated with spermatogonial proliferation (pcna, nanog), cell cycle transition (cyclinb1, cyclind1), and meiosis (aldh1a2, cyp26a1, sycp3). Both EE2 and EES significantly lowered plasma 11-ketotestosterone levels in males, likely by inhibiting the expression level of genes for its synthesis (scc, cyp17a1 and cyp11b2), and increased 17β-estradiol (E2) levels, possibly through upregulating the expression of cyp19a1a. A significant increase in tnfrsf1a expression and the tnfrsf1a/tnfrsf1b ratio in EE2-high and EES-treated males also suggests increased apoptosis via the extrinsic pathway. Further investigation showed that both EE2-high and EES diminished the sexual behavior of male fish, accompanied with reduced E2 levels in the brain and the expression of genes in the kisspeptin/gonadotropin-releasing hormone system. Interestingly, the sexual behavior of unexposed females paired with treated males was also reduced, indicating a synergistic effect. This study suggests that EES have a more severe impact on reproduction than EE2-low, and EEs could interfere not only with spermatogenesis in fish, but also with the sexual behaviors of both exposed males and their female partners, thereby leading to a more significant disruption in fish reproduction.

Gendering Toxic Contamination: Toxic Risks, Bodies, and Pregnancies in Gold Mining and Coca Farming Communities in the Bajo Cauca Region

AbstractThis paper investigates women's everyday reproductive struggles in contexts of toxic contamination and the tensions emerging between toxic exposure and care in women's experiences of motherhood. While scientific framings of reproductive disruptions understand social identities as pre‐existing the experience of toxic risks, in this paper I argue that, in toxic territories, the categories of “contaminating” and “contaminated” actors interact with other categories of identity, such as gender and race, shaping social relations. Drawing on 13 months of ethnographic fieldwork conducted in the Bajo Cauca region among gold mining and coca farming communities, I investigate the everyday processes of gendered subject formation that unfold in toxic territories and the emergence of “faulty” gendered identities for rural mothers. Building on scholarship in feminist geography and Latin American feminist science and technology studies, I argue that ineffective forms of integration of gender in the institutional debate on toxic contamination reproduce, rather than challenge, the invisibility of rural women before the state.

From cradle to grave: Deciphering sex-specific disruptions of the nervous and reproductive systems through interactions of 4-methylbenzylidene camphor and nanoplastics in adult zebrafish

4-methylbenzylidene camphor (4-MBC) and micro/nanoplastics (MNPs) are common in personal care and cosmetic products (PCCPs) and consumer goods; however, they have become pervasive environmental contaminants. MNPs serve as carriers of 4-MBC in both PCCPs and the environment. Our previous study demonstrated that 4-MBC induces estrogenic effects in zebrafish larvae. However, knowledge gaps remain regarding the sex- and tissue-specific accumulation and potential toxicities of chronic coexposure to 4-MBC and MNPs. Herein, adult zebrafish were exposed to environmentally realistic concentrations of 4-MBC (0, 0.4832, and 4832 μg/L), with or without polystyrene nanoplastics (PS-NPs; 50 nm, 1.0 mg/L) for 21 days. Sex-specific accumulation was observed, with higher concentrations in female brains, while males exhibited comparable accumulation in the liver, testes, and brain. Coexposure to PS-NPs intensified the 4-MBC burden in all tested tissues. Dual-omics analysis (transcriptomics and proteomics) revealed dysfunctions in neuronal differentiation, death, and reproduction. 4-MBC-co-PS-NP exposure disrupted the brain histopathology more severely than exposure to 4-MBC alone, inducing sex-specific neurotoxicity and reproductive disruptions. Female zebrafish exhibited autism spectrum disorder-like behavior and disruption of vitellogenesis and oocyte maturation, while male zebrafish showed Parkinson's-like behavior and spermatogenesis disruption. Our findings highlight that PS-NPs enhance tissue accumulation of 4-MBC, leading to sex-specific impairments in the nervous and reproductive systems of zebrafish.

Dose-dependent alteration in hepatic and cerebral glucose metabolism following exposure to polystyrene microplastic in Wistar rats

Background: Recently, microplastics (MPs) with dimensions less than 5 mm have gained more attention due to their adverse impact on the environment and living creatures. Polystyrene (PS) particle is a key element of primary microplastics, which are causing numerous health issues such as interruption of energy metabolism, oxidative stress, neurotoxicity, immunotoxicity, digestive gland disorders, reproductive disruption, and genotoxicity in marine living organisms. Method: Alteration in carbohydrate metabolism was evaluated in male Wistar rats (six weeks of age) after four weeks of oral exposure to polystyrene microplastic (PS-MP) at three different doses (0.5mg/L, 5mg/L and 50 mg/L via drinking water). Results: Polystyrene exposure caused a significant decrease in blood glucose, liver glycogen, and pyruvic acid content in liver and cerebral tissue. Free amino nitrogen content significantly altered in the liver and cerebrum in a dose-specific manner. The LDH activity was found to be decreased in the liver, whereas it increased in the cerebral cortex of rats in a dose-responsive fashion. Enzymes like glucose 6-phosphatase, GOT, GPT, and succinate dehydrogenase activities demonstrated differential effects on the liver and cerebrum of rats in terms of energy metabolism. Conclusion: It is suggested that sub-acute polystyrene exposure significantly perturbs glucose metabolism by inducing hypoglycemia associated with decreased glycolysis and increased TCA cycle enzyme function in rat liver in a dose-dependent manner. Gluconeogenesis is also affected differentially by metabolic adjustment in the studied organs.

Heritable CRISPR Mutagenesis of Essential Maternal Effect Genes as a Simple Tool for Sustained Population Suppression of Invasive Species in a Zebrafish Model.

Invasive species control is important for ecological and agricultural management. Genetic methods can provide species specificity for population control. We developed heritable maternal effect embryo lethality (HMEL), a novel strategy allowing negative population pressure from HMEL individuals to be transmitted within a population across generations. We demonstrate the HMEL technique in zebrafish through genome-integrated CRISPR/Cas targeted mutagenic disruption of nucleoplasmin 2b (npm2b), a female-specific essential maternal effect gene, causing heritable sex-limited disruption of reproduction. HMEL-induced high-efficiency mutation of npm2b in females suppresses population, while males transmit the HMEL allele across generations. HMEL could be easily modified to target other genes causing sex-specific sterility, or generalized to control invasive fish or other vertebrate species for environmental conservation or agricultural protection.

Exposure to zinc oxide nanoparticles induced reproductive toxicities in male Sprague Dawley rats

BackgroundThis research delves into the reproductive toxicology of zinc oxide nanoparticles (ZnO-NPs) in male Sprague Dawley rats. It specifically examines the repercussions of Zn accumulation in the testes, alterations in testosterone levels, and histopathological changes in the gonadal tissues. AimsThe primary objective of this study is to elucidate the extent of reproductive toxicity induced by ZnO-NPs in male Sprague Dawley rats. The investigation aims to contribute to a deeper understanding of the potential endocrine and reproductive disruptions caused by ZnO-NPs exposure. MethodsCharacterization techniques including SEM-EDX and XRD affirmed the characteristic nature of ZnO-NPs. Twenty-five healthy post weaning rats (200–250 g) were intraperitoneally exposed to different concentrations of ZnO-NPs @ 10 or 20 or 30 mg/kg BW for 28 days on alternate days. ResultsResults showed significant dose dependent decline in the body weight and testicular somatic index of rats. It also showed significant dose dependent accumulation of Zn in testis with increasing dose of ZnO-NPs. Conversely, serum testosterone level and sperm count were reduced with increasing dose of ZnO-NPs. Histological results showed dose dependent abnormalities i.e., vacuolization, edema, hemorrhage, destruction of seminiferous tubules, loss of germ cells and necrosis in rat testis. ConclusionThe findings of this study clearly indicate that high doses of zinc oxide nanoparticles (ZnO-NPs) can adversely affect the structural integrity and functional efficacy of the male reproductive system. Given these results, it becomes crucial to implement stringent precautionary measures in the utilization of ZnO-NPs, particularly in cosmetics and other relevant sectors. Such measures are imperative to mitigate the toxicological impact of ZnO-NPs on the male reproductive system and potentially on other related physiological functions. This study underscores the need for regulatory vigilance and safety assessments in the application of nanotechnology to safeguard human health.

Report of <i>Maruca vitrata</i> (F) Nucleopolyhedrovirus

This study explores the potential of nucleopolyhedroviruses (NPVs) as a sustainable solution for managing legume pod borer Maruca vitrata (F). Distinctive signs of viral infection, such as suspended deceased larvae on cowpea leaves, and virus spread have been observed. Microscopic examination reveals characteristic polyhedral inclusion bodies (PIBs), confirming MaviNPV as the causative agent. Symptoms, including decreased activity and mortality in younger larvae, larval-pupal intermediates and deformed pupae have been observed. Reproductive disruption is evident through the absence of an egg mass and discharge of fluid from emerged adults. Bioassay results highlight age-dependent susceptibility, with higher mortality in early instars.

Effect of nanocurcumin on fertility in murine model of polycystic ovary syndrome.

The precise pathophysiology of polycystic ovary syndrome (PCOS) is not well-founded. In an attempt to fill this gap, the current study was executed to probe the effect of nanocurcumin (NCC) on ovarian tissue, in vitro fertilization (IVF) and pre-implantation embryo development in a mouse model of PCOS. Fifty adult female mice were randomly categorized into five equal groups including non-treated control and PCOS (receiving 0.20 mg estradiol valerate (EV) intra-peritoneally once a day for 21 days) as well as NCC12.50 + PCOS, NCC25 + PCOS and NCC50 + PCOS (receiving respectively 12.50, 25.00 and 50.00 mg kg-1 NCC daily along with EV injection through oral gavages for 21 days) groups. Subsequently, ovarian histo-architecture and total anti-oxidant capacity, and malonaldehyde and catalase levels as well as in vitro fertilizing potential, early embryonic development and serum testosterone concentration were analyzed. Results showed that NCC in a dose-dependent manner improved ovarian cyto-architectural organization and oxidant/anti-oxidant balance along with IVF rate and pre-implantation embryo development in PCOS mice. These findings revealed that NCC at the doses of 25.00 and 50.00 mg kg-1 could alleviate PCOS-linked reproductive disruptions in female mice.

Comparative Analyses of Reproductive Caste Types Reveal Vitellogenin Genes Involved in Queen Fertility in Solenopsis invicta.

The red imported fire ant (Solenopsis invicta Buren) is a social pest species with a robust reproductive ability that causes extensive damage. Identification of the genes involved in queen fertility is critical in order to better understand the reproductive biology and screening for the potential molecular targets in S. invicta. Here, we used the mRNA deep sequencing (RNA-seq) approach to identify differentially expressed genes (DEGs) in the transcriptomes of three reproductive caste types of S. invicta, including queen (QA) and winged female (FA) and male (MA) ants. The genes that were specific to and highly expressed in the queens were then screened, and the Vg2 and Vg3 genes were chosen as targets to explore their functions in oogenesis and fertility. A minimum of 6.08 giga bases (Gb) of clean reads was obtained from all samples, with a mapping rate > 89.78%. There were 7524, 7133, and 977 DEGs identified in the MA vs. QA, MA vs. FA, and FA vs. QA comparisons, respectively. qRT-PCR was used to validate 10 randomly selected DEGs, including vitellogenin 2 (Vg2) and 3 (Vg3), and their expression patterns were mostly consistent with the RNA-seq data. The S. invicta Vgs included conserved domains and motifs that are commonly found in most insect Vgs. SiVg2 and SiVg3 were highly expressed in queens and winged females and were most highly expressed in the thorax, followed by the fat body, head, and epidermis. Evaluation based on a loss-of-function-based knockdown analysis showed that the downregulation of either or both of these genes resulted in smaller ovaries, less oogenesis, and less egg production. The results of transcriptional sequencing provide a foundation for clarifying the regulators of queen fertility in S. invicta. The functions of SiVg2 and SiVg3 as regulators of oogenesis highlight their importance in queen fecundity and their potential as targets of reproductive disruption in S. invicta control.

Maternal supplementation of alpha-lipoic acid ameliorates prenatal cytarabine-induced mutilation in reproductive development and function in F1 male adult rats.

Cytarabine (CYT), a prevalent anticancer drug for blood cancers, detrimentally affects male reproductive development and function. Alpha-lipoic acid (ALA), a universal antioxidant, offers defense against chemical-induced reproductive dysfunction. Our study sought to explore ALA's protective role against prenatal CYT-induced reproductive impairment in F1 male adult rats. Pregnant rats were divided into 5 groups and administered normal saline, ALA 200mg/kg, CYT 12.5mg/kg, CYT 25mg/kg, and CYT 25mg/kg + ALA 200mg/ kg from gestational day 8 to 21. On postnatal day 73, F1 male rats were sacrificed, and general, oxidative, steroidogenic, spermatogenic, histological, and morphometrical parameters were evaluated. Prenatal CYT caused dose-dependent reductions in body weight, testis, and accessory gland weights; elevated oxidative stress; delayed puberty onset; sperm anomalies (decreased count, motility, viability, seminal fructose; increased morphological anomalies); impeded steroidogenesis (lower testosterone, follicle-stimulating hormone, luteinizing hormone, 3β-Hydroxysteroid dehydrogenase(HSD), 17β-HSD, and elevated cholesterol); and testicular histopathological and morphometric disturbances. Maternal supplementation of ALA was found to alleviate all the CYT-induced reproductive disruptions. The present work accentuates the beneficial actions of ALA against CYT-induced impairment in reproductive development and functions by combating disruptions in oxidative balance, steroidogenesis, spermatogenesis, and testicular histological aberrations. However, future experimental and clinical studies are warranted to explore the molecular mechanisms involved in the ALA's protection against prenatal CYT-induced testicular injury.

Diversity and inclusion in sport leadership: a longitudinal review of the United States Olympic and Paralympic Committee

ABSTRACT Purpose This paper is to examine the progression of gender and racial inclusion made within the leadership of the United States Olympic and Paralympic Committee (USOPC) and determine what effect benchmarking has had on their inclusion efforts. Methodology Using USOPC’s Diversity and Inclusion Scorecard, the article will examine the gender and racial inclusivity thresholds and use the lens of critical mass to identify possible examples of homo-social reproduction disruption. Findings USOPC is broadly successful in achieving benchmark goals. However, closer analysis of their Equality, Diversity and Inclusion (EDI) scorecards reveals remaining structural barriers to be overcome. These relate specifically to racial and ethnic EDI. Longitudinally, females have achieved critical mass that has also translated to critical mass of women within Senior and Mid-Level management. Conversely, the USOPC has consistently failed to achieve Critical Mass within its Board of Directors (BOD), which is also replicated at the Senior and Mid-Level management levels. Overall, findings positively support the argument that critical mass positively contributes to the inclusion of marginalised populations. Originality There is no existing research that has examined the relationships between USOPC’s goals for inclusion and actual achievement of inclusion. There is limited research that uses critical mass as a lens to examine USOPC inclusion data longitudinally, or how critical mass may have affected homo-social reproduction within the USOPC.

Dietary solutions for aluminum embryotoxicity: A study in Danio rerio using spirulina and okra-spirulina diets

Aluminum (Al) is a versatile element commonly employed in various industries and water treatment processes. However, its presence in aquatic ecosystems can elicit adverse effects on organisms, particularly the Danio rerio fish species. Aluminum exposure has been associated with a spectrum of issues, ranging from oxidative stress to behavioral anomalies, reproductive disruptions, and morphological alterations in these organisms. This research aimed to assess the impact of aluminum chloride (AlCl3) on D. rerio embryos and explore strategies to mitigate its effects. Three dietary groups (commercial, okra-spirulina, and spirulina) were studied, focusing on embryonic development, oxidative damage, and gene expression changes. The study revealed that diets enriched with spirulina and okra-spirulina effectively reduced aluminum-induced embryotoxicity, oxidative stress, and gene expression alterations, surpassing the commercial diet. However, all AlCl3-exposed groups experienced adverse effects on embryonic development, including hatching anomalies, structural deformities, and cardiac delays. The okra-spirulina group showed milder toxic responses. In conclusion, this study highlights the potential of spirulina and okra-spirulina diets in mitigating aluminum-triggered oxidative stress and apoptosis in D. rerio. It underscores the need for future research on embryonic development and carries significant implications for environmental conservation and the well-being of aquatic organisms in aluminum-contaminated environments.

Influence of pollution on fish reproduction in the southern waters of Lake Ladoga

The southern waters of Lake Ladoga have important fishery significance - as a place for spawning, feeding and fishing. The hydrological features of this water area, combined with the location of sources of pollution, contributed to the creation of an increased level of anthropogenic load - massive toxicosis of fish and disruption of the process of natural reproduction, which was noted in the eighties of the last century. The period of early ontogenesis of fish is the most sensitive in the life cycle of fish, and this especially affects salmon and whitefish, which are especially sensitive to anthropogenic impacts, including toxicological factors. As studies have shown, the impact of pollutants has also had a negative impact on other fish species whose spawning grounds are located in this water area. Recent ichthyopathological studies of fish in this water area, which includes three bays: Shlisselburgskaya, Volkhovskaya and Svirskaya, showed massive damage to fish by toxicosis, which prompted a study of early juvenile fish in the littoral areas of the bays. It was shown that in the surveyed water areas from 30 to 70% of early juveniles (larvae, fry) are affected by toxicosis with visual manifestations of the pathological process in the bone tissue, visual, circulatory system, etc. Typical anomalies are craniofacial defects, spinal anomalies, eye defects, of cardio-vascular system. It has been shown that the bone, circulatory, and visual systems are very sensitive to the effects of toxicants in the early stages. Population reproduction is an integral expression of the influence of the combined action of environmental factors and the fish organism itself. The results of the studies showed a pronounced disruption of the natural reproduction of fish, which negatively affects the productivity of the reservoir. Preventive measures for fish reproduction are associated with the reclamation of polluted spawning grounds and factory reproduction of valuable fish species. Typical anomalies are craniofacial defects, spinal anomalies, eye defects, and cardiovascular system defects. It has been shown that the bone, circulatory, and visual systems are very sensitive to the effects of toxicants in the early stages. Population reproduction is an integral expression of the influence of the combined action of environmental factors and the fish organism itself.

The Effect of Silver Nanoparticles on the Digestive System, Gonad Morphology, and Physiology of Butterfly Splitfin (Ameca splendens).

The aim of this study was to determine the effects of silver nanoparticles (AgNPs) on the morphology and enzymatic activity of butterfly splitfin (Ameca splendens). Individuals of both sexes, aged about five months, were exposed to AgNPs at concentrations of 0 (control group), 0.01, 0.1, and 1.0 mg/dm3 for 42 days. On the last day of the experiment, the fish were euthanized, subjected to standard histological processing (anterior intestine, liver, and gonads), and analysed for digestive enzyme activity in the anterior intestine and oxidative stress markers in the liver. Fish in the AgNP 0.01 and 0.1 groups had the lowest anterior intestinal fold and enterocyte height. However, there were no statistically significant changes in the digestive enzyme activity in the anterior intestine. Analysis of enzymatic activity in the liver showed an increase in superoxide dismutase activity in fish in the AgNP 0.1 group. Histological analyses showed that AgNPs inhibited meiotic divisions at prophase I in a non-linear manner in ovaries and testes. In the AgNP 0.1 and 1.0 groups, the area occupied by spermatocytes was lower compared to the other groups. These results indicate that exposure to AgNPs may lead to disturbances in morphology and enzymatic activity in the liver and intestine and may lead to disruption of reproduction in populations.

Tetracycline inhibits tick host reproduction by modulating bacterial microbiota, gene expression and metabolism levels.

Ticks are disease vectors that are a matter of worldwide concern. Antibiotic treatments have been used to explore the interactions between ticks and their symbiotic microorganisms. In addition to altering the host microbial community, antibiotics can have toxic effects on the host. In the tick Haemaphysalis longicornis, engorged females showed reproductive disruption after microinjection of tetracycline. Multi-omics approaches were implemented to unravel the mechanisms of tick reproductive inhibition in this study. There were no significant changes in bacterial density in the whole ticks on Day (D)2 or D4 after tetracycline treatment, whereas the bacterial microbial community was significantly altered, especially on D4. The relative abundances of the bacteria Staphylococcus, Bacillus and Pseudomonas decreased after tetracycline treatment, whereas the relative abundances of Coxiella and Rhodococcus increased. Ovarian transcriptional analysis revealed a cumulative effect of tetracycline treatment, as there was a significant increase in the number of differentially expressed genes with treatment time and a higher number of downregulated genes. The tick physiological pathways including lysosome, extracellular matrix (ECM)-receptor interaction, biosynthesis of ubiquinone and other terpenoids-quinones, insect hormone biosynthesis, and focal adhesion were significantly inhibited after 4 days of tetracycline treatment. Metabolite levels were altered after tetracycline treatment and the differences increased with treatment time. The differential metabolites were involved in a variety of physiological pathways; the downregulated metabolites were significantly enriched in the nicotinate and nicotinamide metabolism, galactose metabolism, and ether lipid metabolism pathways. These findings indicate that tetracycline inhibits tick reproduction through the regulation of tick bacterial communities, gene expression and metabolic levels. The results may provide new strategies for tick control. © 2023 Society of Chemical Industry.