Reproductive Cycle Research Articles

The real subsumption of nature and cryopolitics: Temporal fixes in dairy farming in Southern Italy

Water buffaloes have a seasonal cycle of reproduction. Normally they tend to reproduce more when the daylight hours decrease. This seasonal reproduction also means that most of the buffalo calves would be born in autumn and winter in Italy where buffaloes are dairy animals, and milk production would be the highest in these seasons. However, consumer demand for the PDO (Protected designation of origin) mozzarella cheese is the highest in spring and summer. In order to deal with the imbalances between the seasonality of milk production and mozzarella consumption, and the strict regulations of the PDO cheese production, farmers and veterinarians resort to a temporal fix, and they regularly deseasonalise buffalo reproduction. However, there is an obvious discrepancy between the use of this and other fixes (cryotechnologies) generally associated with industrial agriculture, and the idea of traditional and sustainable food production. By engaging with relevant economic geography and political ecology literature, this paper investigates the temporal fixes in dairy farming and agri-food production through an in-depth empirical analysis of deseasonalisation, as a particular form of the real subsumption of nature, and cryopolitics in buffalo mozzarella cheese production in Southern Italy. The work presented in this article is based on multi-sited qualitative field research of buffalo farming and mozzarella cheese production in Campania region. This paper also has wider implications on how socio-ecological fixes shape ‘just-in-time’ animal agriculture and agri-food production.

Embryology of the fat-tailed dunnart (Sminthopsis crassicaudata): A marsupial model for comparative mammalian developmental and evolutionary biology.

Marsupials are a diverse and unique group of mammals, but remain underutilized in developmental biology studies, hindering our understanding of mammalian diversity. This study focuses on establishing the fat-tailed dunnart (Sminthopsis crassicaudata) as an emerging laboratory model, providing reproductive monitoring methods and a detailed atlas of its embryonic development. We monitored the reproductive cycles of female dunnarts and established methods to confirm pregnancy and generate timed embryos. With this, we characterized dunnart embryo development from cleavage to birth, and provided detailed descriptions of its organogenesis and heterochronic growth patterns. Drawing stage-matched comparisons with other species, we highlight the dunnarts accelerated craniofacial and limb development, characteristic of marsupials. The fat-tailed dunnart is an exceptional marsupial model for developmental studies, where our detailed practices for reproductive monitoring and embryo collection enhance its accessibility in other laboratories. The accelerated developmental patterns observed in the Dunnart provide a valuable system for investigating molecular mechanisms underlying heterochrony. This study not only contributes to our understanding of marsupial development but also equips the scientific community with new resources for addressing biodiversity challenges and developing effective conservation strategies in marsupials.

Effects of Exposure to Electromagnetic Fields (EMFs) on Biological Systems

Electromagnetic Field (EMF) is a natural phenomenon; however, anthropogenic activities have significantly shifted its equilibrium, leading to potential deleterious effects on biological systems. As technology becomes more integrated into daily life, the increased use of electronic devices has contributed to a rise in man-made EMF exposure. This exposure can affect biological systems on physiological and molecular levels, raising concerns about its potential effects on animal development, reproductive systems, and overall ecosystem health. The review explores the physiological effects of exposure to static, extremely low-frequency (ELF), and radiofrequency (RF) fields, analyzing how EMF impacts oxidative stress, reproductive physiology, cardiovascular function, brain and nervous system activity, and DNA/RNA integrity. It also acknowledges the emerging concern of EMF in aquatic environments, where underwater power supplies and extensive underwater cable networks are sources of EMF exposure that may affect marine and freshwater species. The potential effects on marine life include disruptions to migratory patterns, altered reproductive cycles, and changes in aquatic biodiversity. The review acknowledges that research on EMF has improved over time, but significant gaps and information remain. It emphasizes the need for immediate attention to address the challenges and opportunities in this field.

Gendered Harm and Social Abandonment: Stories of the Dooars Women Tea Garden Workers

The Tea Tribes of the Dooars in West Bengal are of the numerically preponderant culturally and socially dispossessed Adivasi population of Chota Nagpur and make up 80% of the tea plantation labour force. These tribes especially its women who form around 60% of the labour pool in the Dooars, serve as crucial social capital for the sustenance and burgeoning of the plantation industry. The tribes exhibit localised and hybridised social customs that have historically been in a dialectic relationship with the culture of commerce that predominates a capitalist bureaucratic organisation. This acculturation and an unfortunate reign of neglect have given birth to distinctive social arrangements, with the article examining the curious social currents of lone motherhood and abandonment of women shaping the household and thereby the social reproduction cycle of the tea industry. By invoking a feminist methodology, qualitative in-depth interpretive interviews of lone mothers and deserted women have been conducted to understand their renditions of gendered neglect and subliminal violence, while attempting to discover their position in the communitas of the tea industry. The study was conducted in the district of Jalpaiguri, with a heavy concentration of the Scheduled Tribe (62%) of the Adivasi subgroup found in its 89 registered tea gardens. The ‘thick’ descriptions of women’s narratives reveal nuanced notions of gender and intimate partner abuse, that shine light on violence characterised by its distinctive low intensity and its latent and subliminal nature evinced in the breach of a social compact. The nature of mistreatment and abuse that they describe opens up conceptual chinks in existing feminist literature on violence while providing further avenues to deliberate upon them. Imperfect, yet partial access to education, social media and government outreach as tools of modernity are however stoking aspirations for social justice, ineffectively handled by poorly trained and gender unresponsive socio-legal and bureaucratic agents.

On-target, dual aminopeptidase inhibition provides cross-species antimalarial activity.

To combat the global burden of malaria, development of new drugs to replace or complement current therapies is urgently required. Here, we show that the compound MMV1557817 is a selective, nanomolar inhibitor of both Plasmodium falciparum and Plasmodium vivax aminopeptidases M1 and M17, leading to inhibition of end-stage hemoglobin digestion in asexual parasites. MMV1557817 can kill sexual-stage P. falciparum, is active against murine malaria, and does not show any shift in activity against a panel of parasites resistant to other antimalarials. MMV1557817-resistant P. falciparum exhibited a slow growth rate that was quickly outcompeted by wild-type parasites and were sensitized to the current clinical drug, artemisinin. Overall, these results confirm MMV1557817 as a lead compound for further drug development and highlights the potential of dual inhibition of M1 and M17 as an effective multi-species drug-targeting strategy.IMPORTANCEEach year, malaria infects approximately 240 million people and causes over 600,000 deaths, mostly in children under 5 years of age. For the past decade, artemisinin-based combination therapies have been recommended by the World Health Organization as the standard malaria treatment worldwide. Their widespread use has led to the development of artemisinin resistance in the form of delayed parasite clearance, alongside the rise of partner drug resistance. There is an urgent need to develop and deploy new antimalarial agents with novel targets and mechanisms of action. Here, we report a new and potent antimalarial compound, known as MMV1557817, and show that it targets multiple stages of the malaria parasite lifecycle, is active in a preliminary mouse malaria model, and has a novel mechanism of action. Excitingly, resistance to MMV15578117 appears to be self-limiting, suggesting that development of the compound may provide a new class of antimalarial.

Screening methods for thermotolerance in pollen.

Plant reproduction is highly susceptible to temperature stress. The development of the male gametophyte in particular represents a critical element in the reproductive cycle with high sensitivity to elevated temperatures. Various methods have been used to test the effect of temperature stress on pollen performance or to determine the degree of susceptibility of given species and genotypes. The information gained informs the development of new crop varieties suited to grow under warmer conditions arising through climate change and facilitates predicting the behavior of natural populations under these conditions. The characterization of pollen performance typically employs the terms pollen viability and pollen vigor, which, however, are not necessarily used consistently across studies. Pollen viability is a nominal parameter and is often assayed relying on cellular features as proxy to infer the capability of pollen grains to germinate and complete double fertilization. Alternatively, pollen germination can be determined through in vitro growth assays, or by monitoring the ability of pollen tubes to complete different progamic steps in vivo (ability to reach an ovule, release sperm cells, lead to seed set). Pollen vigor is an ordinal parameter that describes pollen tube growth rate or the efficiency of pollen tube growth as inferred by its morphology or growth pattern. To ensure consistent and relevant terminology, this review defines these terms and summarizes the methodologies used to assess them.

High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis

The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.

13 Impact of precision feeding during gestation on the productive career of sows over three reproductive parities

Abstract The aim of this study was to evaluate the impact of precision feeding during gestation on the career performances and longevity of sows, initially gilts, monitored over three successive reproductive cycles. Four isoenergetic treatments were compared: two conventional constant-concentration feeding strategies (0.53 % DIS Lys) with feed supply either constant (flat feeding; FF) or variable (bump feeding; BF), and two precision feeding strategies based on the InraPorc model applied considering either the mean weight by parity (PFP) or the individual weight of each sow at breeding (PFI). Four groups, representing 393 gilts, were followed from breeding to weaning over three cycles. Body weight and backfat depth were measured at breeding, 90 d of gestation, parturition, and weaning. Feed consumption was monitored daily. Litter variables were measured, including birth and weaning weight, mortality, and overall body weight gain. A mixed model was used to analyze differences between the four treatments using the sow as the experimental unit for performance analysis during the third reproductive cycles. For the analysis of the overall productive career over the three reproductive cycles, the performances of the two conventional strategies (with constant Lys DIS concentration feeding, CONV) were compared with the two precision feeding strategies (PF). During the third cycle, PFP and PFI sows had a lighter body weight at the beginning of gestation than the FF sows (P < 0.01), but increased their body weight gain during gestation (P < 0.001). Backfat loss in PFP and PFI sows during lactation was greater compared with BF sows (P = 0.05), FF sow being intermediate. PFP sows had a lower stillborn rate (P = 0.04) and tended to have less total piglet mortality (P = 0.06) than FF and BF sows. Over the three reproductive cycles, the stillborn rate and total piglet mortality were less in PF sows than in CONV sows (respectively -0.9 %; P = 0.02 and -1.5 %; P = 0.03). PF sows weaned more piglets during their three cycles than CONV sows did (+ 0.7; P = 0.03), with weaning litter weight gain also increasing for PF sows (+3.7 %; P = 0.02). The culling rate of gilts after three cycles did not differ significantly among treatments (P = 0.27), but tended to be greater for PF sows after one cycle (+4.9 %; P = 0.08). The results seem to show a lasting benefit of precision feeding for sows, with a decrease in piglet mortality during lactation, suggesting greater piglet viability without significantly decreasing sow longevity.

275 Assessment of changes in hemoglobin concentration (Hb) in sows and their offspring over two consecutive reproductive cycles

Abstract There remains a knowledge gap regarding changes in hematological parameters, such as Hb, throughout the reproductive cycle of a sow. The principle aim of this study was to assess Hb concentartions in sows and their offspring over at least two consecutive reproductive cycles. Blood Hb measurements were initiated during the gilt stage and continued through parities 1 and 2, with measurements taken at six time points (d 30, 60, 90, and 112 of gestation; d 2 and 17 of lactation) involving a total of 13 sows. Sow body weight (BW) during gestation was 193.2 ± 38.1 kg for parity 1 and 220.7 ± 26.2 kg for parity 2; in lactation, sow BW was 201.5 ± 14.3 kg for parity 1 and 214.0 ± 19.6 kg for parity 2. Sow daily iron (Fe) intake, based on analyzed Fe content, was 0.621 ± 0.06 g during gestation and 1.79 ± 0.15 g during lactation across parities 1 and 2, which represents more than a 2-fold greater Fe intake than NRC 2012 requirement estimates. All liveborn piglets (n = 204 for parity 1; n = 201 for parity 2) underwent Hb measurements. Blood Hb concentrations were assessed within 24 h of birth before iron supplementation (200 mg iron dextran) and again at 17 d of age. Sows and piglets were classified as either anemic (Hb < 10 g/dL) or non-anemic (Hb ≥ 10 g/dL). Analysis of variance included the main effect of day, parity and their interaction based on Tukey’s comparison. In gestation Hb was less (P = 0.03) at d 90 in parity 1 and at d 90 and 112 in parity 2 (Table 1). Across parity, Hb was less (P = 0.02) at d 60 in parity 2. In lactation, Hb was least (P = 0.0002) at d 17 in parity 1 where sows were deemed anemic; in parity 2, sows were deemed anemic throughout lactation. The total number of piglets born and born alive was 17.15 ± 2.03 and 16.0 ± 1.9, respectively, for parity 1, and 17.0 ± 3.11 and 15.85 ± 2.41, respectively, for parity 2. Regardless of parity, piglet Hb was greater (P < 0.02) at weaning compared with birth. However, Hb concentrations were greater (P < 0.0001) at both time points in parity 2 piglets. There was a reduced incidence of anemia at birth (39.1% vs. 59.02%, respectively) and weaning (14.2% vs 36.1%, respectively) among piglets born in parity 2 compared with parity 1. The decline in sow Hb status with parity, particularly in lactation, suggests the need to explore strategies to improve Hb in sows with advancing parity. Alternatively, piglet Hb status improved with parity, indicating a need to modify iron supplementation methods to facilitate greater Hb in parity 1 litters.

PSI-3 Effect of feed and water consumption patterns during the lactation period on wean-to-estrus interval in weaned sows

Abstract There is sufficient evidence that adequate feed and water consumption during the lactation period positively influences sow body condition at weaning. Optimum body condition score after the lactation period decreases sow wean-to-estrus interval and non-productive sow days and promotes sow reproductive performance in the following reproductive cycle, in general. However, feed and water intake patterns have not been extensively studied in commercial sow research; thus, the objective of this study was to determine the effect of feed and water consumption patterns in the lactation period on wean-to-estrus interval in weaned sows. This trial was conducted in a commercial sow farm located in southwestern Minnesota in March 2023. Each lactation feeder was outfitted with a MealMeter 2.0 device (PigEasy, LLC, Templeton, IA), which uses a rotating feed dispenser to release feed ad libitum at the request of each sow. In addition, the MealMeter 2.0 device utilizes sensors to track the number of times feed and water were accessed at 15-min time intervals across the entire lactation period. Average daily feed (ADF) and water accessions (ADW) were summarized for each sow during the lactation period (n = 84 sows). Root mean squared error (RMSEF and RMSEW for feed and water accessions, respectively) was calculated from the residuals of the regression between days post-farrowing and ADF and ADW for each sow and was considered a measure of variation in feed and water accessions during the lactation period. Moreover, the number of days from weaning to the first estrus was recorded and defined as the wean-to-estrus interval (WTE). Due to the distribution of WTE, sows with a WTE ≤ 5 d and WTE > 5 d were separated into a binary classifier (0 = WTE ≤ 5 d and 1 = WTE > 5 d). The relationship between each feed and water measurement and WTE class was estimated using a logistic regression model fit with R Statistical Software. Average daily feed and water accessions were negatively associated with WTE class (P- = 0.07 and 0.04, respectively; Table 1), indicating that as feed and water accessions increase, the probability of observing a WTE greater than 5 d decreases. In addition, RMSEF and RMSEW were also negatively associated with WTE class, which suggests that as the variation in each measure across the lactation period increases, the probability of observing a WTE greater than 5 d is reduced. This result was not expected and, thus, requires further investigation. Nonetheless, results from this study suggest that the mean and variation of daily feed and water accessions are associated with WTE and sufficient consumption of nutrients during the lactation period is critical to reducing the number of days to first estrus in weaned sows.

171 Current limitations to implement fiber in U.S. sow and nursery diets, and nutritional strategies to support ideal fiber profile

Abstract The importance of fiber in swine nutrition is increasingly recognized, and the consequences of insufficient dietary fiber can be significant. Consequently, U.S. production nutritionists have begun exploring the incorporation of fiber into their nutrition programs. However, incorporating fiber into diets is not without challenges. Analytical capabilities for assessing fiber content have improved, yet accessing accurate data remains a hurdle. Furthermore, the cost of analysis limits the ability of nutritionists to utilize these advanced methods for ingredient analysis. The lack of information around fiber requirements in the diet may be due to the insufficient methodology that has historically been available to measure the indigestible fraction of the diet. In the nursery phase, research findings on the effects of fiber have been mixed, likely influenced by the health status of the animals. Short-term growth performance trials may not fully capture the benefits of fiber, and more comprehensive, long-term studies focusing on health-related parameters are lacking. Similarly, research on sow nutrition faces challenges due to the limitations of barn structures and feed lines. Sow trials typically involve only a small number of treatments, often requiring before- and after- assessments. Moreover, the benefits of fiber are more apparent in later reproductive cycles, necessitating prolonged research efforts. Given the limited phases in sow diets, primarily lactation and gestation, conducting sow research is both challenging and costly. Evidence from European literature and recent U.S. studies suggests that the total dietary fiber and the level of soluble, fermentable fiber have a crucial role in swine diets, particularly for sows and piglets. However, the availability and affordability of such fiber types in the U.S. are limited. The majority of fiber-rich ingredients in the U.S. consist mostly of insoluble fiber. To address this limitation, technological advancements will be needed to transform available fiber sources into the desired fiber constructs, rather than relying solely on fiber-rich ingredients. A stimbiotic, which encourages fiber fermentation, may be key to achieving the desired fiber profile. The addition of a stimbiotic has been shown to increase the digestibility of fiber. It also increases the capacity of the beneficial microbiome to break down and ferment fiber, which leads to an increase in the production of volatile fatty acids (acetic, propionic and butyric). In conclusion, U.S. swine nutritionist must explore alternative dietary strategies to capturing the ideal fiber composition. Key word: fiber, nursery, sow

Analyzing a series of ligands against malaria through the application of molecular docking, molecular quantum similarity, and reactivity indices

Background The primary goal of this research is to underscore the significance of molecular docking in the context of malaria drug discovery. Molecular docking plays a crucial role in comprehending the interactions between prospective drugs and the target proteins found in Plasmodium parasites. The study delves into the docking interactions of various compounds, emphasizing the necessity of stabilizing the active site to formulate potent and selective drugs. Methods The research focuses on highlighting compound-specific interactions with residues, stressing the importance of stabilizing the active site to design drugs tailored to specific target proteins. Inhibiting the function of these target proteins disrupts the life cycle of the malaria parasite. Quantum Similarity Analysis, utilizing Overlap and Coulomb operators, is employed to identify electronic similarities. The resulting quantum similarity values guide subsequent chemical reactivity analysis. Global reactivity indices such as chemical potential, hardness, softness, and electrophilicity contribute to drug design by showcasing compound-specific indices that underscore the significance of stability and electrophilicity. Fukui functions are utilized to visualize regions for stabilization, providing insights crucial for potential malaria treatment. Results The enhancement of drug-target binding affinity is observed through stabilizing interactions in the active site. Understanding electrophilicity at the active site emerges as a critical factor in drug design and selectivity. The rational manipulation of electrophilic interactions holds promise for developing potent and selective drugs against malaria. Consequently, the integration of molecular docking, quantum similarity analysis, and chemical reactivity indices offers a comprehensive approach to malaria drug discovery. Conclusions The study identifies potential lead compounds, emphasizing the crucial role of stabilizing the active site. Additionally, it sheds light on electronic considerations vital for the design of effective and resistance-resistant drugs. The insights provided by Fukui functions into regions susceptible to -H bond formation make these compounds promising candidates for malaria treatment.

Analysis of control impact on the HIV reproductive cycle in a cross infection epidemic model

AbstractDespite the great advances in HIV treatment, there are still several processes in the dynamics of the infection that are not yet fully understood. Some evidences show that when the therapy HAART is suspended, infection resumes, suggesting the existence of virus reservoirs; these have been identified in the lungs, brain and guts. In this paper, following the compartmental approach, a recently proposed model is addressed, considering in particular the brain as virus reservoir and distinguishing the cells depending on whether they are inside or outside the brain, both infected and non infected. Controls mimicking the drug action are introduced and the model is analysed in terms of equilibrium points and stability, also determining the reproduction number. Numerical results are used to put in evidence the main dynamics characteristics.

Advanced Swine Management: Infrared Imaging for Precise Localization of Reproductive Organs in Livestock Monitoring

Traditional methods for predicting sow reproductive cycles are not only costly but also demand a larger workforce, exposing workers to respiratory toxins, repetitive stress injuries, and chronic pain. This occupational hazard can even lead to mental health issues due to repeated exposure to violence. Managing health and welfare issues becomes pivotal in group-housed animal settings, where individual care is challenging on large farms with limited staff. The necessity for computer vision systems to analyze sow behavior and detect deviations indicative of health problems is apparent. Beyond observing changes in behavior and physical traits, computer vision can accurately detect estrus based on vulva characteristics and analyze thermal imagery for temperature changes, which are crucial indicators of estrus. By automating estrus detection, farms can significantly enhance breeding efficiency, ensuring optimal timing for insemination. These systems work continuously, promptly alerting staff to anomalies for early intervention. In this research, we propose part of the solution by utilizing an image segmentation model to localize the vulva. We created our technique to identify vulvae on pig farms using infrared imagery. To accomplish this, we initially isolate the vulva region by enclosing it within a red rectangle and then generate vulva masks by applying a threshold to the red area. The system is trained using U-Net semantic segmentation, where the input for the system consists of grayscale images and their corresponding masks. We utilize U-Net semantic segmentation to find the vulva in the input image, making it lightweight, simple, and robust enough to be tested on many images. To evaluate the performance of our model, we employ the intersection over union (IOU) metric, which is a suitable indicator for determining the model’s robustness. For the segmentation model, a prediction is generally considered ‘good’ when the intersection over union score surpasses 0.5. Our model achieved this criterion with a score of 0.58, surpassing the scores of alternative methods such as the SVM with Gabor (0.515) and YOLOv3 (0.52).

Effect of Estrogens on Apoptosis in the Pituitary of Viscachas (Lagostomus maximus maximus)

Estrogens, acting through their receptors (ERα and ERβ), regulate cell turnover in the pituitary gland, influencing cell proliferation and apoptosis across various species. However, their role in pituitary processes in seasonally reproducing animals remains poorly understood. This study aims to investigate the influence of estrogens, through the expression of their specific receptors, on the apoptosis of PD cells in relation to sexual maturity, the reproductive cycle, and pregnancy in a seasonal reproductive rodent (Lagostomus maximus maximus). ERα and caspase-3-cleaved (CASP3c) immunoreactive (-ir) cells were identified through immunohistochemistry. Apoptotic cells were detected using the TUNEL technique, with quantitative analysis facilitated by image analysis software, alongside measurement of serum estradiol levels using radioimmunoassay The immunostaining pattern for ERα included nuclear (ERαn) and cytoplasmic (ERαc) staining. In male viscachas, ERα expression significantly increases from immature to adult animals, correlating with the rise in serum estradiol levels and a decrease in the percentage of apoptotic cells. During the gonadal regression period in adult males, a decrease in the number of ER-ir cells and serum levels of estradiol corresponds with an increase in the number of apoptotic cells. In females, serum levels of estradiol peaked during mid-pregnancy, coinciding with a significant decrease in the number of apoptotic cells in the PD. Simultaneously, the percentage of ERαn-ir cells reaches its maximum value during late pregnancy, indicating the need to maintain the protective action of this gonadal hormone throughout the extensive pregnancy in these rodents. Regional ERα receptor expression and apoptotic cells appear to be associated with distinct PD cell populations and their hormonal responses. Finally, elevated estradiol levels coincide with diminished apoptotic cells in the male reproductive cycle and during pregnancy, suggesting an antiapoptotic role of estradiol in this species.

The male reproductive cycle of the brown basilisk Basiliscus vittatus (Squamata: Corytophanidae) from Tabasco, Southern Mexico.

We used histological and morphometric methods to study the testis and associated glands, including the epididymis, ductus deferens, and renal sexual segment (RSS), of specimens of Basiliscus vittatus sampled from Tabasco, Mexico (17.5926° N, 92.5816° W). Samples were collected throughout 1 year, which included the dry (February to May) and rainy (June to January) seasons. Spermatogenesis in B. vittatus is active throughout the year, but a significant increase in the testicular volume, diameters of seminiferous tubules, height of the germinal epithelium, spermiogenesis, and released spermatozoa occur in the dry season. During the rainy season, all aforementioned parameters decreased except the secretory activity of the epididymis and the RSS, which increased concomitant with an increase of the spermatozoa population within the ductus deferens. These data strongly suggest that B. vittatus reproduce year-round, but males exhibit a peak in spermatogenic activity during the dry season and a peak in insemination and/or copulation at the beginning of the rainy season. We highlight the importance of analyzing not only the testis but also accessory ducts and glands when determining the reproductive cycles of reptiles. The reproductive cycle of B. vittatus is discussed in relation to the environmental conditions of Southern Mexico and is compared to that of other squamates.

Application of ultrasonography in abalone gonadal evaluation

The precise assessment of the gonad status and gamete development level is an essential step in abalone breeding. However, traditional methods are damaging to the animals, causing the waste of a quality parent. Ultrasound imaging as a noninvasive technique is a candidate substitute. This study aimed to verify the application of ultrasonography to the assessment of abalone gonad condition. Pacific abalones (n = 20) were randomly selected for ultrasonography, another six abalones in different gonad maturation stages (mature, between mature and immature, and immature) were also subjected to the same detection and histological analysis. Abalones (n = 10) were induced to spawn, and the changes in the gonad index and the types of germ cells were determined before and after spawning. Thirty-six female abalones were selected and divided into a high-gonad index group (HGI) and a low-gonad index group (LGI) according to the gonad index determined by ultrasonography, and their reproductive performance was compared during the entire breeding process. There was no significant difference in gonad index or gonad relative average thickness (GRAT) obtained from ultrasonography and histological methods. The gonad index and GRAT measured by ultrasound images significantly decreased after spawning. After spawning, a minimal quantity of mature gametes remained in gonad tissue as reflected in histology images. In a reproductive trial, the HGI group showed comprehensive and overwhelming reproductive advantages compared to the LGI group in total fecundity, relative fecundity, fertilization rate, hatching rate, abnormality rate, and attachment rate. Ultrasonography was demonstrated to be useful as a noninvasive method to evaluate abalone gonad condition. The ultimate goal is to achieve tracing and monitoring the abalone reproductive cycle through the ultrasound technique.

Reproductive traits of the deep-sea shrimp Plesionika williamsi (Decapoda: Pandalidae) from the eastern-central Atlantic

The reproductive aspects of all Plesionika species are relatively well known worldwide, except for the deepest species of the genus, Plesionika williamsi, for which little information is available throughout its range. The ovarian maturity, sex ratio, brood size, and size-depth distribution of the deep-sea shrimp Plesionika williamsi (Pandalidae) in the Canary Islands (eastern-central Atlantic) were analysed. Ovigerous females were observed all year round, with the highest number of ovigerous females recorded between July and October. The presence of a greater number of ovigerous females during the summer may reflect a high local availability of food or the optimal abiotic conditions, which are factors with a strong influence on reproduction. The presence of non-ovigerous mature females throughout the year indicates that their resting period in the reproductive cycle occurs asynchronously. The physiological size at first sexual maturity was 19.24 mm in carapace length (CL) and the length at first sexual maturity was estimated at 23.15 mm CL. Estimates of size at first sexual maturity based on ovigerous females describe the result of the reproduction process, whereas size at first sexual maturity based on ovarian maturity deals with physiological preparation for reproduction. The modal size class of egg production was 24–30 mm CL, which yielded 83.22% of the population egg production. Plesionika williamsi is an iteroparous species that can produce small eggs during egg extrusion. The mean number of external embryos carried by females was 3048 and can be considered a true approximation of the number of larvae released in each batch, which depend on the conditions existing in each system. The shallower individuals are associated with a depth stratum that represents the boundary between two water masses present in the Canary Islands. The increase in size with depth is related to the presence of submarine volcanic canyons, which constitutes a flow channel of surface organic matter to depth.

Chemical ecology of plankton parasitism in algae

Abstract Plankton parasites such as viruses, bacteria, fungi, and unicellular eukaryotes are associated symbionts colonizing algal groups in aquatic ecosystems. They occur within a network of microbe–microbe interactions in which they parasitize phytoplankton and seaweeds, i.e., primary producers generating organic carbon and forming the basis of marine food webs. These parasites use algae as a source of nutrients and reproduce at the expense of their host, causing infectious symptoms leading to disease and death. Plankton parasites can reduce the algal populations, and the infection of one specific species may, in turn, favor the development of another, influencing the seasonal succession of algal blooms in oceans, seas, and lakes. Many parasites have free-living stages that zooplankton graze upon, representing a significant trophic link in food webs. The biology and life cycle of plankton parasites are well investigated in marine and freshwater algal hosts. Still, the chemical signaling mediating these microbial interactions and the effect of co-occurring symbionts remain underexplored. This review focuses on the diversity of plankton parasites infecting algae, with a particular emphasis on unicellular eukaryotes. The ecological role of plankton parasites, the mechanisms regulating cellular infection and host resistance, and the interplay of alga-parasite interactions with coexisting microorganisms are discussed.

ToF-SIMS imaging shows specific lipophilic vitamin alterations in chronic reprotoxicity caused by the emerging contaminant Pravastatin in Gammarus fossarum

Blood lipid-lowering agents, such as Pravastatin, are among the most frequently used pharmaceuticals released into the aquatic environment. Although their effects on humans are very well understood, their consequences on freshwater organisms are not well known, especially in chronic exposure conditions. Gammarus fossarum is commonly used as sentinel species in ecotoxicology because of its sensitivity to a wide range of environmental contaminants and the availability of standardized bioassays. Moreover, there is an increased interest in linking molecular changes in sentinel species, such as gammarids, to observed toxic effects. Here, we performed a reproductive toxicity assay on females exposed to different concentrations of pravastatin (30; 300; 3,000 and 30,000 ng L−1) during two successive reproductive cycles and we applied ToF-SIMS imaging to evaluate the effect of pravastatin on lipid homeostasis in gammarids. Reproductive bioassay showed that pravastatin could affect oocyte development in Gammarus fossarum inducing embryotoxicity in the second reproductive cycle. Mass spectrometry imaging highlighted the disruption in vitamin E production in the oocytes of exposed female gammarids at the second reproductive cycle, while limited alterations were observed in other lipid classes, regarding both production and tissue distribution. The results demonstrated the interest of applying spatially resolved lipidomics by mass spectrometry imaging to assess the molecular effects induced by long-term exposure to environmental pharmaceutical residues in sentinel species.