Gonadal Growth Research Articles

Integrated metabolomic and transcriptomic analyses identify critical genes in eicosapentaenoic acid biosynthesis and metabolism in the sea urchin Strongylocentrotus intermedius

Gonads are the only edible part of the sea urchin and have great potential as a health-promoting food for human consumption. Polyunsaturated fatty acids (PUFAs) are important necessary nutrients that determine not only the nutritional value of sea urchins but guarantee their normal growth and reproduction. However, the information on the molecular mechanisms of PUFA biosynthesis and metabolism in this species remains elusive. In this study, we used Strongylocentrotus intermedius as our model species and conducted integrated metabolomic and transcriptomic analyses of potentially critical genes involved in PUFA biosynthesis and metabolism during gonad growth and development, mainly focusing on eicosapentaenoic acid (EPA). We found six differentially accumulated metabolites associated with PUFA in the metabolomic analysis. More differentially expressed genes (DEGs) were related to PUFA in testis than ovary (1823 DEGs in testis and 1499 DEGs in ovary). We verified 12 DEGs by RNA-Seq results and found that Aldh7a1, Ecm3, Fads2, and Hsd17b12 genes had similar expression patterns in EPA concentration during gonad growth and development. In contrast, the other DEGs were downregulated and we inferred that EPA or PUFA may be metabolized as energy during certain periods. Our metabolic and genetic data will facilitate a better understanding of PUFA regulation networks during gonad growth and development in S. intermedius.

Reproductive biology, morphology, and morphometry of ovaries and oviducts of Trachemys scripta elegans in Brazilian Cerrado

ABSTRACT: Although Trachemys scripta elegans is an exotic species popular as a pet in Brazil, studies on reproductive biology and capacity are non-existent in the Brazilian Cerrado. This study analyzed ovarian and oviduct characteristics and the egg production capacity of T. scripta elegans grown in this biome. The findings will associate with the size of the specimens and the sexual maturity, aiming at comparisons with native and exotic populations, as well as interspecific and contributing to the understanding of its impact on the invaded ecosystems and the establishment of eradication programs. Thus, 39 females had evaluated the body biometry and the morphology and morphometry of the ovaries and oviducts. G2 (N=20): with Class I (>5-10mm) follicles, with Class I and Class II (>10-fold) follicles, 25mm) and G3 (N=9) with Class I, Class II and Class III (>25mm) follicles. Analysis of variance, Scott-Knott’s test, and Pearson’s correlation analysis showed that there was no significant difference between the groups in body biometry; in the mean gonadosomatic index and gonadal morphometry, only the width of the oviducts in the right antimer and the mass and width in the left antimer were higher in G3, the only one that presented eggs. There was positive and harmonic development between body mass, carapace, and plastron, and gonadal growth occurred concomitantly with body growth, indicating a higher reproductive potential and a positive relationship between the size of the litter and the female litter. The gonadosomatic index proved to be an excellent reproductive indicator, and the ovarian evaluation was a better indicator of sexual maturity than the maximum carapace length. Ovaries were irregular structures, without delimitation between the cortical and medullary regions and filled with vitelogenic follicles of different diameters, atresic follicles, and corpora lutea, which reflected the ovarian complexity of the species and the presence of follicular hierarchy. In the scarce stroma, two germinative beds were observed per ovary and the presence of gaps very close to the follicles and associated with the blood vessels. Analysis of gonadal tissue revealed three types of oocytes according to cytoplasmic characteristics: homogeneous, vesicular or vesicular in the cortex with apparent granules. Oviducts were functional and separated, joining only in the final portion to form the cloaca and subdivided into infundibulum, tuba, isthmus, uterus, and vagina. The structure of the uterine tube was composed of serosa, muscular and mucous, which was full of glands. The presence of eggs in the oviducts indicated that the specimens can reproduce in the Brazilian Cerrado. This study provides necessary and relevant information on the reproductive biology and capacity of T. scripta elegans in the Brazilian Cerrado and can contribute to the understanding of its impact on the invaded ecosystems and the establishment of eradication programs. The extraction of females with capacity can reduce the annual reproductive yield of the species and decrease its effect on local biodiversity.

Sex‐specific differences in gonopore and gonadal growth trajectories in the brooding sea urchin, Abatus cavernosus (Spatangoida)

AbstractThe heart urchin Abatus cavernosus shows sexual dimorphism characterized by the development of external brood pouches and the enlargement of gonopores in brooding females. Relationships between body size, gonopore size, and gonadal maturation in each sex were examined for inflection points using piecewise regression models (PRM). Opening of the gonopore occurred at 15.5 mm test length. Inflection points in the gonadal growth and gonopore diameter trajectories were clustered at smaller sizes in males (23 and 24.2 mm, respectively) than in females (25.1 and 25.9 mm), indicating sex‐specific differences in sexual maturation. Gonopore growth showed positive allometry at pre‐adult stages of development in both sexes, but isometry and negative allometry in adult females and males, respectively. Gonadal growth was initiated at smaller sizes and proceeded at a higher rate with increasing body size in males than in females. Identification of inflection points in gonopore and gonadal growth trajectories, using objective PRM, allows the determination of life stages and sexual maturation for individuals, thus providing a complementary tool for population studies.

Artificial light at night, in interaction with spring temperature, modulates timing of reproduction in a passerine bird.

The ecological impact of artificial light at night (ALAN) on phenological events such as reproductive timing is increasingly recognized. In birds, previous experiments under controlled conditions showed that ALAN strongly advances gonadal growth, but effects on egg‐laying date are less clear. In particular, effects of ALAN on timing of egg laying are found to be year‐dependent, suggesting an interaction with climatic conditions such as spring temperature, which is known have strong effects on the phenology of avian breeding. Thus, we hypothesized that ALAN and temperature interact to regulate timing of reproduction in wild birds. Field studies have suggested that sources of ALAN rich in short wavelengths can lead to stronger advances in egg‐laying date. We therefore tested this hypothesis in the Great Tit (Parus major), using a replicated experimental set‐up where eight previously unlit forest transects were illuminated with either white, green, or red LED light, or left dark as controls. We measured timing of egg laying for 619 breeding events spread over six consecutive years and obtained temperature data for all sites and years. We detected overall significantly earlier egg‐laying dates in the white and green light vs. the dark treatment, and similar trends for red light. However, there was a strong interannual variability in mean egg‐laying dates in all treatments, which was explained by spring temperature. We did not detect any fitness consequence of the changed timing of egg laying due to ALAN, which suggests that advancing reproduction in response to ALAN might be adaptive.

Gonads or body? Differences in gonadal and somatic photoperiodic growth response in two vole species.

To optimally time reproduction, seasonal mammals use a photoperiodic neuroendocrine system (PNES) that measures photoperiod and subsequently drives reproduction. To adapt to late spring arrival at northern latitudes, a lower photoperiodic sensitivity and therefore a higher critical photoperiod for reproductive onset is necessary in northern species to arrest reproductive development until spring onset. Temperature-photoperiod relationships, and hence food availability-photoperiod relationships, are highly latitude dependent. Therefore, we predict PNES sensitivity characteristics to be latitude dependent. Here, we investigated photoperiodic responses at different times during development in northern (tundra or root vole, Microtus oeconomus) and southern vole species (common vole, Microtus arvalis) exposed to constant short (SP) or long photoperiod (LP). Although the tundra vole grows faster under LP, no photoperiodic effect on somatic growth is observed in the common vole. In contrast, gonadal growth is more sensitive to photoperiod in the common vole, suggesting that photoperiodic responses in somatic and gonadal growth can be plastic, and might be regulated through different mechanisms. In both species, thyroid-stimulating hormone β-subunit (Tshβ) and iodothyronine deiodinase2 (Dio2) expression is highly increased under LP, whereas Tshr and Dio3 decrease under LP. High Tshr levels in voles raised under SP may lead to increased sensitivity to increasing photoperiods later in life. The higher photoperiodic-induced Tshr response in tundra voles suggests that the northern vole species might be more sensitive to thyroid-stimulating hormone when raised under SP. In conclusion, species differences in developmental programming of the PNES, which is dependent on photoperiod early in development, may form different breeding strategies as part of latitudinal adaptation.

EFFECTS OF PHOTOPERIODS ON THE CLONED GTH GENES IN HARD-LIPPED BARB (Osteochillus hasseltii)

Photoperiod is one factor that regulates the endocrine gland’s production of hormones necessary for gonadal growth and development, gametogenesis and reproductive cycles in fish reproduction. However, studies on the influence of photoperiod on tropical fishes are still limited. Hence, this study investigates the effects of photoperiod on the hard-lipped barb, particularly, the genetic expression of its cloned gonadotropin hormones I (GtH-I) and II (GtH-II) genes. Experiment was designed using three treatments; 14L: 10D (control), 8L: 16D (short photoperiods), and 18L: 6D (long photoperiods). Four aquariums with nine fishes/tank were used, serving as replicates. The fishes were kept under these different photoperiod lengths for eight weeks.  Pituitary activities were observed by measuring the GtH genetic expression.  The length of cDNA GtH-I was 222 bp, and the cDNA GtH-II was 354 bp. The GtH-I precursors encoded by cDNA consisted of 67 amino acids, including mature peptide. The level of GtH gene expression significantly increased as longer photoperiods were administered. The results indicated that photoperiod lengths affect the hard-lipped barb reproductive performance.

Atlantic cod Gadus morhua save energy on stone reefs: implications for the attraction versus production debate in relation to reefs

Reefs are structurally complex habitats that are degraded in numerous coastal areas. Structural complexity is often associated with elevated fish abundance, and recent studies have indicated that such structural complexity (e.g. reefs) not only acts as a fish aggregator, but also increases fish production. The objective of this study was to advance this knowledge by investigating if an underlying mechanism of the observed productivity is related to reduced metabolic rates (proxy for energy use) of fish in reef habitats. Using juvenile Atlantic cod Gadus morhua, we tested the hypothesis that fish energy use differs between fish occupying stone reef and sand bottom habitats. Metabolic rate (MO2) was estimated using intermittent flow respirometry in simulated stone reef and sand bottom habitats over 24 h. Results revealed that G. morhua in the stone reef habitat exhibited significantly reduced accumulated MO2 compared to G. morhua in the sand bottom habitat. Likewise, there was a tendency for lower mean standard metabolic rates of the fish in stone reefs, although this pattern was not statistically significant. There are many mechanisms that may underpin elevated productivity in structurally complex habitats such as reefs, including better access to shelter and increased food availability. Our study adds to these mechanisms by showing that G. morhua save energy when occupying stone reefs as compared to sandy bottoms, energy which may be allocated to somatic and gonadal growth.

Can artificial diets be a feasible alternative for the gonadal growth and maturation of the sea urchin Paracentrotus lividus (Lamarck, 1816)?

AbstractParacentrotus lividus (Lamarck 1816) has high‐value reddish‐orange gonads that are regarded as a delicacy. In this study, three jellified diets have been tested for 90 days to assess the effect of different diets on P. lividus somatic and gonadal growth, gonad color, and reproductive state. All diets contained agar as a gelling agent and consisted of: maize and spinach (A); maize, spinach, and macroalga Laminaria digitata (B); and maize, spinach, and pumpkin Cucurbita maxima (C). Diet B was the most successful in promoting somatic growth with regard to test diameter (1.2 mm month−1) and total wet weight (79.9 mg ind−1 day−1). The individuals from Diet A presented a higher final gonadosomatic index (9.07 ± 2.39%) where all sea urchins initially presented with an index of 3.33 ± 0.02%. Diets A and C led to a marked advance (p < .05) in the gametogenic cycle (66.7% and 46.7% of the individuals with mature gametes, respectively), while Diet B resulted in less‐developed gonadal stages, which are more appropriate for commercial purposes in terms of sensorial characteristics appreciated by the consumers. The gonad color analyses confirmed a redder roe in females and also the suitability of C. maxima as a potential gonad color enhancer for P. lividus.

Manipulation of photoperiod perception advances gonadal growth but not laying date in the great tit

In seasonal environments, organisms use biotic and abiotic cues to time various biological processes that are crucial for growth, survival and reproductive success. Photoperiod is the best‐known cue used to regulate gonadal development, migration and moult of many animal species. In birds, the relationship between photoperiod and gonadal development is clearly established, but we have little understanding on whether photoperiod also regulates actual timing of egg laying under natural conditions. Elucidating the link between photoperiod and timing of breeding is however key to understand whether an evolutionary change in sensitivity to photoperiod is a possible mechanism through which organisms could adjust their seasonal timing in response to climate warming. Here, we investigated the causal relationship between photoperiod, gonadal growth and laying date in wild female great tits. We experimentally increased the photoperiod perceived by the birds in spring by clipping head feathers, and we subsequently monitored gonadal development in the lab and egg laying dates in the wild. We show that our manipulation increased the photoperiod perceived by the birds to a level that approximately corresponds to an advancement of ten calendar days. This increase in perceived photoperiod led to an acceleration of gonadal development, but not to an advancement of egg laying dates. Our results indicate that photoperiod sensitivity is not constraining the advancement of laying date under current environmental conditions and suggest that evolution of sensitivity to other supplementary cues is necessary to advance reproduction under global warming.

Transcriptome analysis to characterize the genes related to gonad growth and fatty acid metabolism in the sea urchin Strongylocentrotus intermedius.

Sea urchin gonads of both sexes, commonly termed "roe", are highly valued seafood delicacies, and Strongylocentrotus intermedius is considered one of the tastiest sea urchins. In order to produce high-quality gonads for consumption and clarify the mechanism of gonad growth and development of the sea urchin, more genetic information, especially at the transcriptome level, is needed. A more thorough understanding of sea urchin gonad growth and development in both sexes could enable regulation of these processes at several stages with the aim of suppressing gametogenesis in order to produce high-quality gonads for consumption. The adult sea urchins S. intermedius were cultured for 3months, and were sampled for the gonadal transcriptome analysis which has been performed on the RNAs of three male and female adults of S. intermedius in each gonad development stage. Illumina sequencing raw sequence data was deposited in the NCBI Sequence Read Archive (SRA) database (PRJNA532998). It generated 560,196,356 raw reads and 548,956,944 clean reads were acquired, which were assembled into 107,850 transcripts with 44,124 genes. Comparative analysis showed the differentially expressed genes (DEGs) from 114 to 2566. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to determine the functional significance of these DEGs. We have selected 9 genes related to growth and 12 genes related to fatty acid biosynthesis and metabolism in sea urchin gonads. These data for sea urchins were intended to provide markers for gonad growth and development that can be accumulated for use in aquaculture applications.

Seasonal changes in European whitefish muscle and invertebrate prey fatty acid composition in a subarctic lake

Abstract Ambient light and temperature show extreme seasonal variation in subarctic lakes due to the midnight sun period in summer and cold polar night period in winter. These changes have clear impacts on fish feeding and reproduction cycles, potentially affecting the fatty acid (FA) composition of muscle. Despite extensive research into fish FA over recent decades, we know little about intra‐annual changes of fish FA profile and content. We studied intra‐annual changes in the FA profile (mol%) and content (mg g‐1 dry weight) of sexually mature European whitefish (Coregonus lavaretus) muscle in a large and deep subarctic lake located in northern Fennoscandia. We collected fish, zooplankton, and benthic macroinvertebrate samples during 3 ice‐covered months, including December (during whitefish spawning), and 3 open‐water months. Fish size, age, sex, stomach content and fullness, and gonadosomatic index were also assessed as co‐variates. Whitefish changed diet from benthic macroinvertebrates in winter to zooplankton in summer. Generally, whitefish somatic growth was slow and most energy was used for gonad growth. Zooplankton had higher total content and different profile of FA compared to benthic macroinvertebrates. Increased zooplanktivory in summer was detected with higher α‐linolenic acid (ALA, 18:3n‐3) and stearidonic acid (SDA, 18:4n‐3) percentage and content as well as increased the ratio of polyunsaturated FAs (PUFAs) of n‐3 and n‐6 family (n‐3/n‐6 ratio) in fish muscle. Whitefish gonadal growth and development occur during the summer growing season and continue until the initiation of spawning in early winter. We found that the content of physiologically crucial PUFA, eicosapentaenoic acid (EPA, 20:5n‐3), docosahexaenoic acid (DHA, 22:6n‐3), and arachidonic acid (ARA, 20:4n‐6) decreased by c. 60% between late summer and the spawning period in early winter. After spawning, total FA content of whitefish muscle increased rapidly, reaching the maximum recorded level in mid‐summer. Intra‐annual changes in whitefish muscle FA profiles and contents were modified both by available diet and reproductive phase; however, reproductive physiology was clearly a stronger driver of the changes in muscle FA composition. Results suggest marked changes in intra‐annual FA composition of fish muscle, an important factor that should be considered in future studies and especially in long term monitoring programs. Future studies are needed to determine whether these inter‐annual FA patterns revealed in this study can be extended to different regions and to e.g. adipose or spring spawning species.

Gonad Histology, Proximate Composition and Growth Efficiency of Nile Tilapia Fed with Pawpaw (Carica papaya) Seeds Powder

The study was carried out to determine the effect of different inclusion levels of pawpaw seeds powder (PSP) on the proximate composition, growth and histological structure of Nile tilapia gonads. Nile tilapia were treated with pawpaw seeds powder at four levels at 0 g, 4 g, 8 g and 12 g PSP/kg feed for 60 days. The proximate composition of the carcass of the Nile tilapia showed that the 8 g PSP/kg feed treatment group had the highest values (mean ± SE) of Crude protein and ash (53.97 ± 0.094 and 20.05 ± 0.35) respectively. The highest body weight gain and specific growth rate was achieved at the 8 g PSP/kg treatment level but this treatment level showed the lowest feed conversion ratio. Histology of gonads of Nile tilapia treated with different levels of PSP revealed that ovaries and testes of 0 g PSP/kg feed were normal. Ovaries of the 4 g PSP/kg feed had degenerative stromas while testes had scanty spermatozoa. At 8 g PSP/kg feed, the ovaries showed increased atretic follicles and testes had degeneration of spermatozoa.Treatment with 12 g PSP/kg feed resulted in severe atretic follicles of the ovaries and deformation of seminiferous tubules and erosion of spermatozoa of the testes. The results of this study showed that pawpaw seeds powder can be used to control the breeding of Nile tilapia in production units.

Identification of gnrh2 and gnrh3 and their expression during brood pouch growth and short-term benzo(a)pyrene exposure in lined seahorse (Hippocampus erectus)

Gonadotropin-releasing hormones (GnRH) regulate gonadal growth of teleosts. Benzo(a)pyrene (BaP) functions as a reproductive endocrine disruptor. Furthermore, endocrine regulation on brood pouch growth of Syngnathidaes is elusive. To better understand the role of GnRH in brood pouch growth and effects of BaP on reproductive endocrine in lined seahorse (Hippocampus erectus), gnrh2 and gnrh3 genes were identified. Results showed that lined seahorse GnRH2 and GnRH3 precursors included the conservative tripartite structure and their transcripts highly expressed in brain as other teleosts. Expression profiles of gnrh2 and gnrh3 transcripts were detected during brood pouch growth. Results indicated that brain gnrh2 transcripts remarkably increased at the middle-stage and late-stage of brood pouch growth, while brain gnrh3 transcripts significantly raised at the early-stage and middle-stage. These suggested that GnRH2 and GnRH3 regulated brood pouch growth at different stages. Short-term BaP exposure in lined seahorse was performed. Transcripts of gnrh2 and gnrh3 remarkably increased in females and males exposed to BaP. Besides, plasma 17-beta estradiol (E2) levels presented a reduced trend during female fish exposed to BaP. This revealed that BaP functioned as anti-estrogenic effects and it may result in high expression of gnrh mRNA. However, plasma 11-ketone testosterone (11-KT) levels showed an increased trend during male fish exposed to BaP. Taken together, these indicated interesting results of BaP on reproduction in each sex of seahorse. These observations contribute to provide novel information of regulation on brood pouch growth and effects of BaP on reproductive endocrine in Syngnathidaes.

Metabolomic changes and polyunsaturated fatty acid biosynthesis during gonadal growth and development in the sea urchin Strongylocentrotus intermedius

Strongylocentrotus intermedius is an important commercial species of sea urchin distributed in the coastal waters of China. However, the metabolomic changes that accompany its gonadal growth and development stages remain unclear. In this study, we have histologically observed gonad growth stages, analyzed the fatty acid composition, and employed an untargeted metabolomic approach to investigate the metabolites associated with the gonadal growth and development of S. intermedius, as well as the biosynthesis and metabolism of polyunsaturated fatty acids (PUFAs) at different stages and in different sexes. The gonad mass of sea urchin increased from 0.70 ± 0.18 g in January (at the recovering stage) to 8.78 ± 2.89 g in July (the reproductive stage), with the GSI increasing from 4.02 ± 0.88% to 16.86 ± 2.79%. We have analyzed 34 types of fatty acids, such as arachidonic acid, eicosapentaenoic acid, etc., of which PUFAs were the dominant fatty acid class in this species, accounting for >48.55% of the total. In the metabolomic analysis, linolelaidic acid, sciadonic acid, cis-8,11,14,17-eicosatetraenoic acid, adrenic acid, docosapentaenoic acid, and tetracosapentaenoic acid were detected in the differentially expressed metabolites of the unsaturated fatty acids biosynthesis pathway. We found that the most significant functional pathways during gonadal growth and development were “arachidonic acid metabolism”, “alpha-linolenic acid metabolism” and “linoleic acid metabolism”, which are all related to fatty acid metabolism. These results will provide valuable information on the possible presence of both exogenous and endogenous fatty acids in sea urchin gonads and the metabolomic changes in S. intermedius during gonadal growth periods, and will further our understanding of the intermediary metabolism and the molecular bases of growth traits in this species.

Chronic and severe hypoxic conditions in Paracas Bay, Pisco, Peru: Consequences on scallop growth, reproduction, and survival

The response of Argopecten purpuratus (Peruvian scallop) to environmental conditions was studied in the upwelling-influenced Bay of Paracas (Peru). Scallops growth and reproduction were monitored weekly over a 7-month period under two conditions (culture depths): on the bottom and 2 m above (suspended culture). At the same time, a high-frequency environmental monitoring was realized at the aforementioned depths. The results indicate that environmental conditions in the Bay are highly variable, especially during the summer: temperature fluctuations up to 8∘C were recorded in less than one day while oxic conditions ranged from oversaturation to anoxia. Milky-turquoise waters discoloration events (sulphide presence suspected) were simultaneously observed together with anoxic conditions and sudden temperature drops. Increased stratification and upwelling favorable winds during the summer might be partly responsible for the observed environmental variability. Higher somatic and gonadal growth were observed in scallops growing in suspended culture compare with bottom culture. This pattern might be related to different environmental conditions at culture depth: turbidity was lower in suspended culture and hypoxic conditions occurred only 18% of the whole study period versus 48% on the bottom. The Gonadosomatic index varied according to an approx. 30-day cycle between winter and late spring and it was synchronous between the different scallop size groups. During summer, when milky waters and anoxic events occurred frequently, cessation of reproduction, somatic weight losses and increased scallop mortality were observed. Exposure to severe hypoxia and related environmental conditions clearly affected scallop bioenergetics and subsequently growth and reproduction. In addition, the occurrence of milky waters harmed the survival of the Peruvian scallop in culture. These results are discussed in terms of management strategies for sustainable scallop aquaculture in the Bay.

Paracentrotus lividus roe enhancement by a short-time rearing in offshore cages using two agar-based experimental feed

In this study, we tested the effect of two agar-based biocomposites (differing for the fish meal source), on the Paracentrotus lividus gonad cycle progression and biochemical composition, in an offshore pilot scale trial. The purpose of this study was to identify a feeding regime for P. lividus that would allow adequate gonadal growth without accelerating the gamete maturation, in order to extend the market period. The purpose was pursued through the use of agar as a binding agent in the manufacturing of biocomposites to be used as feed for P. lividus and the realization of special offshore cages. The gonad index, histology, biochemical composition of fatty acids (FA) and free amino acids (FAA) and volatile molecule fingerprint were evaluated. Both the gonad index and the histological analysis showed a slower gametogenesis progression in the gonads of caged sea urchins with respect to the field collected ones, consistent with our previous results obtained testing a similar feed composition in a recirculating system. The amount and the relative proportions of FA and FAA in the gonads of wild and cultured gonads were similar, while the analysis of the volatile substances of the gonads of the sea urchin conducted using the electronic nose, shows that they vary as a result of the different feeding treatments. These results show that P. lividus sea urchins can be housed, under this feeding regime during the recovery phase of the gonads, without acceleration of the maturation of the gametes and thus in conditions to allow the extension of the market period. Moreover, the here tested agar-based biocomposites make it possible to reduce the management costs of the rearing system as they need to be replaced only once a week, and its environmental impact as they guarantee a limited nutrient dispersion in the water.

The Role of miRNA in Differentiation, Cell Proliferation, and Pathogenesis of Poultry Diseases

To date, several noncoding RNAs are known that play a prominent role in the processes of transcription, translation, and structural conformation of RNA. By binding miRNA to 3'-untranslated regions, mRNA regulates gene expression in animals through inhibition of translation initiation, elongation, and other mechanisms. There is evidence for the differential expression of miRNA that regulates transcription with the inclusion of several stages of myoblast proliferation, differentiation, and apoptosis. These molecules play a significant role in cell differentiation, proliferation, apoptosis, and tumorigenesis. Some miRNAs are known to target 100–200 genes. Polymorphisms of miRNA genes, especially in the competent regions of the genome, can be biomarkers for phenotypic traits important for breeding birds. The findings confirm the key role of miRNA in controlling the metabolic switch that occurs between the embryo development and the chick hatching. Differentially expressed miRNAs and their possible target genes are involved in egg production functions. The available miRNA data complement our understanding of the molecular genetic control underlying abdominal fat accumulation and myogenesis in chickens. Hundreds of differentially expressed miRNAs from individuals differing in body weight were found. A new understanding into the functions of miRNA during chicken gonads’ rapid development is being formed. Hundreds of miRNAs expressed by hypothalamic genes and involved in the initial phase of rapid gonad growth have been identified. There is increasingly clear evidence that miRNA play a major role in regulating the innate immune response and are important effectors in complex host–pathogen interaction networks for salmonellosis, Marek’s disease, carcinogenic, and other diseases. Many of the miRNAs are associated with cell proliferation, apoptosis, and tumorigenesis. Bacterial pathogens are able to modulate the expression of the host miRNAs and affect the regulation of miRNAs and the outcome of infection. Several miRNAs are induced by TLR activation in innate immune cells and target the 3′-untranslated regions of the mRNA encoding the components of the TLR signaling system. Modern genome-editing tools suggest an artificial increase in the diversity of miRNAs and an increased use of miRNAs for directional action. Structure determination of RNA, RNA–RNA, RNA–DNA, and ribonucleoprotein complexes is becoming a rapidly developing area requiring the development of new technologies.

Gestational exposure to an epidemiologically defined mixture of phthalates leads to gonadal dysfunction in mouse offspring of both sexes

The increasing concern for the reproductive toxicity of abundantly used phthalates requires reliable tools for exposure risk assessment to mixtures of chemicals, based on real life human exposure and disorder-associated epidemiological evidence. We herein used a mixture of four phthalate monoesters (33% mono-butyl phthalate, 16% mono-benzyl phthalate, 21% mono-ethyl hexyl phthalate, and 30% mono-isononyl phthalate), detected in 1st trimester urine of 194 pregnant women and identified as bad actors for a shorter anogenital distance (AGD) in their baby boys. Mice were treated with 0, 0.26, 2.6 and 13 mg/kg/d of the mixture, corresponding to 0x, 10x, 100x, 500x levels detected in the pregnant women. Adverse outcomes detected in the reproductive system of the offspring in pre-puberty and adulthood included reduced AGD index and gonadal weight, changes in gonadal histology and altered expression of key regulators of gonadal growth and steroidogenesis. Most aberrations were apparent in both sexes, though more pronounced in males, and exhibited a non-monotonic pattern. The phthalate mixture directly affected expression of steroidogenesis as demonstrated in a relevant in vitro model. The detected adversities at exposures close to the levels detected in pregnant women, raise concern on the existing safety limits for early-life human exposures and emphasizes the need for re-evaluation of the exposure risk.

The Role of Tissue Inhibitors of Metalloproteinases in Organ Development and Regulation of ADAMTS Family Metalloproteinases in Caenorhabditis elegans.

Remodeling of the extracellular matrix supports tissue and organ development, by regulating cellular morphology and tissue integrity. However, proper extracellular matrix remodeling requires spatiotemporal regulation of extracellular metalloproteinase activity. Members of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family, including MIG-17 and GON-1, are evolutionarily conserved, secreted, zinc-requiring metalloproteinases. Although these proteases are required for extracellular matrix remodeling during gonadogenesis in Caenorhabditis elegans, their in vivo regulatory mechanisms remain to be delineated. Therefore, we focused on the C. elegans tissue inhibitors of metalloproteinases (TIMPs), TIMP-1 and CRI-2 Analysis of the transcription and translation products for GFP/Venus fusions, with TIMP-1 or CRI-2, indicated that these inhibitors were secreted and localized to the basement membrane of gonads and the plasma membrane of germ cells. A timp-1 deletion mutant exhibited gonadal growth defects and sterility, and the phenotypes of this mutant were fully rescued by a TIMP-1::Venus construct, but not by a TIMP-1(C21S)::Venus mutant construct, in which the inhibitor coding sequence had been mutated. Moreover, genetic data suggested that TIMP-1 negatively regulates proteolysis of the α1 chain of type IV collagen. We also found that the loss-of-function observed for the mutants timp-1 and cri-2 involves a partial suppression of gonadal defects found for the mutants mig-17/ADAMTS and gon-1/ADAMTS, and that this suppression was canceled upon overexpression of gon-1 or mig-17, respectively. Based on these results, we propose that both TIMP-1 and CRI-2 act as inhibitors of MIG-17 and GON-1 ADAMTSs to regulate gonad development in a noncell-autonomous manner.

The NAO affects the reproductive potential of small tuna migrating from the Mediterranean Sea

Several studies have confirmed that the North Atlantic Oscillation (NAO) has a direct effect on tuna across a range of biological aspects, such as abundance, catchability, recruitment, and physical condition (LC), especially during winter season (NAOw). However, its effect on reproductive biology has been barely investigated. Thus, the main aim of this study was to investigate the effect of the NAO on the physical condition index and gonadosomatic index (GSI) of the three most commercially exploited small species of migrating tuna (i.e. little tunny, bullet tuna, and Atlantic bonito) in the Mediterranean Sea. A positive direct correlation was found between little tunny and Atlantic bonito and the gonadosomatic and the physical condition indexes. In addition, a strong correlation was found between the NAOw and the gonadosomatic and LC indexes, which could lead to higher reproductive investment in gonad growth before the spawning season. In contrast, bullet tuna had a low LC index during peak gonad growth and were less affected by NAOw oscillations. In the case of bullet tuna, these results could be explained by a longer reproductive period that would lead to faster fat consumption before the reproductive period than in the other species considered and greater dependence on the surrounding environmental conditions for reproductive success.