Juvenile Period Research Articles

153 Do pre and postnatal nutrition interact to program reproductive phenotype in sexually mature heifers?

Abstract Objectives were to test the hypothesis that nutritional extremes during pregnancy in the bovine female negatively affect phenotypic characteristics of the estrous cycle of sexually mature offspring, and to determine whether these effects interact with postnatal diets during the juvenile period. Beginning at 90 d of pregnancy, Brangus and Braford (n = 108) beef cows with a female fetus were fed to achieve body condition scores of 7.5–8 (H, obese), 5–5.5 (M, moderate) or 3–3.5 (L, very thin) by the start of the third trimester. Heifer offspring were weaned and fed to gain at either a high (H; 1 kg/d) or low (L; 0.5 kg/d) rate between 4 and 8 months of age, then fed a common growth diet until puberty. Estrous cycles of a subgroup (n = 53) were synchronized using 2 injections of prostaglandin F2α(PGF). Transrectal ultrasonography was employed during the follicular phase of two estrous cycles to evaluate antral follicle count(AFC), rate of growth and size of the ovulatory follicle, size of corpus luteum(CL), and endometrial thickness. Blood samples were collected daily for assay of plasma concentrations of progesterone(P4) and estradiol-17β(E2) by RIA. Preliminary data (n = 35) were analyzed using ANOVA and mixed model procedures. Least Squares Means estrous cycle length (20.9 ± 0.2 days), AFC (19.7 ± 1.0), follicular growth rate (0.81 ± 0.11), ovulatory follicle size (12.8 ± 0.2 mm), CL size (16.8 ± 0.6 mm), and endometrial thickness (14.6 ± 0.3 mm) did not differ among treatments. Heifers in postnatal H group tended (P < 0.1) to have a greater area (arbitrary units) under the E2 curve (12.6 ± 0.6) than postnatal L (11.3 ± 0.5) during the follicular phase. Normalized AUC for P4 was greater (P < 0.03) in L/H (56.94 ± 3.22) than both M/H (42.98 ± 3.61) and L/L (43.66 ± 3.22) groups. Despite marked pre- and postnatal nutritional contrasts, independent and interactive effects of nutritional treatments have been of minor significance or undetectable to date.

Metamorphosis of whitemouth croaker Micropogonias furnieri (Pisces, Sciaenidae)

Fish metamorphosis is an important ontogenetic process with a key role on early stages survival and on successful recruitment to adult populations. The whitemouth croaker (Micropogonias furnieri) is an important commercial resource for the coastal fisheries of Argentina and Uruguay. Metamorphosis, using morphometric and morphological analyses during larval development was studied. Changes in morpho-meristic characters before and after metamorphosis were employed to determine the length interval of this transition by employing Principal Component Analysis. Individuals (n=430) from 4 to 41 mm standard length (SL) were collected in the Río de la Plata estuary (35.45º S, 56.35º W) in March 2006. Length ranges of individual´s developmental stages were associated with the presence of key morphological characters. During early life stages, M. furnieri changes from a big-headed, robust shape larva to a slender and more elongated body form. Most of the morphometric variables showed an inflexion point at 15.2 mm SL, with a 95% confidence interval of 14.0 – 16.4 mm. The anterior part of the body grows faster during early stages, probably related to an intense feeding activity strategy. The completion of pectoral fin rays and the onset of squamation determine the beginning of metamorphosis at 11-12 mm SL. At around 18 mm SL, squamation ends, first barbels develop and the sagittae otolith primordium is closed. The length-at-metamorphosis for M. furnieri was established between 9 to 18 mm SL, since all developmental characters studied highly overlapped at that interval. All those processes are indicative of the beginning of the juvenile period associated to the settlement and the start of a bottom-oriented life-style.

PSII-30 Effects of Prenatal and Postnatal Nutrition on the Concentration of Neuropeptide Y in the Third Ventricle Cerebrospinal Fluid in Beef Heifers

Abstract Nutrition during gestation and early postnatal life can program developmental changes within the reproductive neuroendocrine system that persist until adult life. Here we tested the hypotheses that maternal nutrition during the second and third trimester of gestation and dietary energy intake during the juvenile period interact to affect concentrations of neuropeptide Y (NPY) in the third ventricle cerebrospinal fluid (CSF) after fasting (basal) and in response to peripheral leptin administration in heifer offspring. Bos indicus-influenced beef heifers were developed using a 3 × 2 factorial arrangement of pre- and postnatal dietary treatments. Beginning at the onset of the second trimester of gestation, pregnant Braford and Brangus cows were fed to reach body condition scores of 7.5–8 (H, obese), 5–5.5 (M, moderate), or 3–3.5 (L; very thin) during the third trimester. Heifer offspring were weaned at ~3.5 mo of age and fed to gain at either a relatively high (H; 1 kg/d) or low (L, 0.5 kg/d) rate between 4–8 mo of age, then fed a common diet subsequently. A subgroup of pubertal heifers (n = 6/group) representing 3 of the maternal × postnatal groups (HH, MH, and LL) were ovariectomized and received estradiol replacement after puberty. Cannulas were placed surgically in the third ventricle. After at least a 2-wk recovery period, heifers were fasted for 54 h and CSF was collected every 30 min for 5.5 h, including a 30-min basal and 5-h treatment period involving 3 hourly IV injections of recombinant oleptin (0.2 µg/kg BW). Basal and post-leptin NPY concentrations in the CSF did not differ (P > 0.10) among LL, MH, and HH heifers. Treatment with leptin had no effect (P > 0.10) on NPY concentration in any group. Therefore, neither the interaction of pre- and postnatal nutrition nor exogenous leptin affected third ventricle NPY tone in this experimental model.

Does intraspecific variation in demography have implications for fire management of an obligate‐seeder shrub across its geographic range?

AbstractPredicting changes in the abundance of species over time is a central goal of conservation ecology. Typically, demographic data are used to parameterise models which describe population dynamics. Vital rates of plants vary across a species’ distribution, yet most demographic estimates are spatially constrained. Banksia ornata (Proteaceae), a widespread serotinous obligate‐seeding shrub in southern Australia, has previously had a fire management model developed based on demographic data derived from a chronosequence in one part of the species’ range. We asked: are demographic data collected from a limited geographic range robust for developing population dynamic models that are applied across the broader species’ range? How much variation exists in the demography of species across their range and does this matter for estimating fire return intervals necessary for species persistence? We examine site‐to‐site variation in the pyrodemography of six populations of B. ornata encompassing its geographic range. We documented changes in population density, time to first reproduction and canopy seed bank accumulation in stands varying in age from 0.5 to 55 years. We model year of maximum seed production on demographic parameters such as population starting density and survival rate. Density, primary juvenile period, rates of mortality and seed bank accumulation varied across populations. Primary juvenile period varied across populations (from 6 to <20 years), while time to maximum seed production was estimated to take 34–39 years after fire. Hence, the fire intervals that correspond to minimising extinction risk (due to variation in primary juvenile periods) diverge moreso among populations than the fire intervals that produce (on average) the highest maximum seed production with respect to time since fire. Demographic data collected at different locations in a species’ range are likely valuable for building realistic species response models to disturbance, providing underlying assumptions about key transitions, such as mortality rate, are made explicit.

введение Eucommia ulmoides Oliv. в культуру in vitro

The increasing need for herbal medicines requires the study of not only biological resources of medical plants, but also methods for their reproduction. Of special value are the medicinal plants that have a long history of success in traditional medicine. One of such plants is Eucommia ulmoides Oliv., which belongs to a rare relict species growing in natural conditions, for the most part, in the undergrowth of humid subtropical forests in China, mainly in the middle course of the Yangtze river. E. ulmoides compares favorably with most subtropical plants owing to its significant frost resistance, which makes it possible to cultivate it outside the humid subtropics. It has been widely introduced in Krasnodar Krai and in the Republic of Adygea (Russia) since the mid-20th century and successfully adapted to various environmental conditions in the Northwest Caucasus. The increasing demand for E. ulmoides bark can only be satisfied by laying out industrial plantations. However, the difficulties encountered in the traditional seed reproduction of E. ulmoides (dioecious species, pollen low quality, parthenocarpy, prolonged seed dormancy, irregular fruiting, long juvenile period, etc.) make scientists turn to modern biotechnological methods of plant propagation. While considering cultivation of planting material, we should focus on highly efficient methods that ensure stable and mass reproduction of the plants under study. An important role is played here by in vitro plant regeneration. The effectiveness of biotechnology methods is due to a reduction in timing of obtaining a large number of vegetative progeny of plants difficult for propagation, as well saving of the area required for their cultivation. The conditions for producing an aseptic culture of E. ulmoides were chosen based on the results of the studies. The highest degree of sterilization of E. ulmoides shoot segments was achieved when the explants were sequentially immersed first in 70 % ethanol (30 s) and then in 0.1 % mercuric chloride solution (5 min). With such a sterilization procedure, 63.3 % of the studied cuttings were made sterile, and 56.7 % of them proved to be viable. The optimal composition of the nutrient medium for regeneration of E. ulmoides microshoots has been determined: MS medium complemented with 1 mg/L 6-Benzylaminopurine (BAP) + 0.2 mg/L 1-Naphthaleneacetic acid (NAA). The best media for explant rooting are the following: 2/3 MS + 1.5 mg/L NAA + 30 g sucrose + 7 g agar; 2/3 MS + 1 mg/L NAA + 0.4 mg/L IBA + 30 g sucrose + 7 g agar.

Sowing Green Seed Without Stratification Does Not Shorten Juvenility or Increase Plant Size in Common Lilac (Syringa vulgaris)

Common lilac is an important flowering shrub that accounts for ≈$20 million of sales in the U.S. nursery industry. Cultivar improvement in common lilac has been ongoing for centuries, yet little research has focused on shortening the multiple-year juvenility period for lilacs and the subsequent time required between breeding cycles. The practice of direct-sowing of immature “green” seed has been shown to reduce juvenility in some woody plants, but it has not been reported for common lilac. This study investigated the effects of seed maturity [weeks after pollination (WAP)], pregermination seed treatment (direct-sown vs. cold-stratified), and postgermination seedling chilling on the germination percentage, subsequent plant growth, and time to flower on lilac seedlings. All seedlings were derived from the female parent ‘Ludwig Spaeth’ and the male parent ‘Angel White’. Seeds harvested at 15 and 20 WAP resulted in 58% (sd ± 9.9%) and 80% (sd ± 9.0%) germination, respectively, which were similar to that of dry seed collected at 20 WAP with stratification (62% ± 4.2%). Seedlings from the green seed collected at 15 and 20 WAP were also approximately three-times taller than those of dry seed groups DS1, DS2, and DS3 after the first growing season. Over the next two growing seasons, there were no differences in seedling height across all treatments. Flowering occurred at the beginning of the fourth season and without differences among treatments. These results indicate that the collection and direct sowing of immature, green seed can be used to successfully grow lilac seedlings, but that they do not reduce the juvenility period. However, this method can provide more vegetative growth in year one to observe early vegetative traits such as leaf color, and it can provide more material for DNA extraction to support molecular research.

Sexually dimorphic effects of prolactin treatment on the onset of puberty and olfactory function in mice

The onset of puberty is associated with the psychophysiological maturation of the adolescent to an adult capable of reproduction when olfactory signals play an important role. This period begins with the secretion of the gonadotropin-releasing hormone (GnRH) from GnRH neurons within the hypothalamus. This is regulated by kisspeptin neurons that express high levels of transmembrane prolactin receptors (PRLR) that bind to and are activated by prolactin (PRL). The elevated levels of serum PRL found during lactation, or caused by chronic PRL infusion, decreases the secretion of gonadotropins and kisspeptin and compromised the estrous cyclicity and the ovulation. In the present work, we aimed to evaluate the effects of either increased or decreased PRL circulating levels within the peripubertal murine brain by administration of PRL or treatment with cabergoline (Cab) respectively. We showed that either treatment delayed the onset of puberty in females, but not in males. This was associated with the augmentation of the PRL receptor (Prlr) mRNA expression in the arcuate nucleus and decreased Kiss1 expression in the anteroventral periventricular zone. Then, during adulthood, we assessed the activation of the mitral and granular cells of the main (MOB) and accessory olfactory bulb (AOB) by cFos immunoreactivity (ir) after the exposure to soiled bedding of the opposite sex. In the MOB, the PRL treatment promoted an increased cFos-ir of the mitral cells of males and females. In the granular cells of male of either treatment an augmented activation was observed. In the AOB, an impaired cFos-ir was observed in PRL and Cab treated females after exposure to male soiled bedding. However, in males, only Cab impaired its activation. No effects were observed in the AOB-mitral cells. In conclusion, our results demonstrate that PRL contributes to pubertal development and maturation of the MOB-AOB during the murine juvenile period in a sex-dependent way.

A naturalistic method to test depression: Anticipation of play

The Wistar-Kyoto (WKY) rat was developed as a control for the spontaneous hypertensive rat but has subsequently also been used as a genetic animal model of depression due to its hyper-responsiveness to stress. We used anticipation of social reward (i.e., a play partner) to assess behavioural and vocal differences between the WKY and normal Wistar (WI) rats in the juvenile period. We found marked differences between groups; the WKY rats, were less active, vocalized less, and used significantly fewer types of 50-kHz calls in comparison to their WI counterparts. The animals were re-tested in adulthood and the same differences existed in overall activity, types of vocalizations and the behavioural vocal profiles used by the two groups of animals. These findings provide a robust baseline for an animal model of depression using a social paradigm. This paradigm may be useful to evaluate the efficacy of pharmaceutical interventions as potential treatments of depression in WKY rats.

Propagation Studies in Sapodilla [Manilkara zapota (L.) P. Royen]: A Review

Sapota [Manilkara zapota (L) P. Royen] is an important commercial fruit crop of Sapotaceae family grown for fresh fruits and chicle production. Sapota when propagated by vegetative means, produce true to type plant material and reduces juvenile period and result in early commercial production. Various propagation techniques on different rootstocks were tried for the purpose. Among different rootstocks, khirni (Manilkara hexandra) was found most successful and is used for commercial plant propagation as it possesses high graft compatibility with sapota and plants produce fruits of excellent quality with high yield. Various vegetative propagation techniques have been standardized and used on large scale depending upon season and region. The general techniques used for sapota propagation are softwood grafting, veneer grafting, side grafting, inarching and air layering. Softwood grafting is employed in regions with moderate temperature and high relative humidity which prevent desiccation of scion stick. Veneer and side grafting using mature scion stick is also found effective in regions with variable climates. Inarching technique possess high graft survival rate and is practiced by private nurseries. Propagation through cuttings is not successful in sapota even when treated with rooting hormones. Micro-propagation in sapota by tissue culture techniques have been tried but application remains limited to academics only. This may be due to high phenolic contents and sap exudation in explant. Special protocols for successful root and shoot regeneration are required to be standardized for commercial scale plant propagation.

Sex-dimorphic role of prefrontal oxytocin receptors in social-induced facilitation of extinction in juvenile rats

We previously reported that in the adult animal extinction in pairs resulted in enhanced extinction, showing that social presence can reduce previously acquired fear responses. Based on our findings that juvenile and adult animals differ in the mechanisms of extinction, here we address whether the social presence of a conspecific affects extinction in juvenile animals similarly to adults. We further address whether such presence has a different impact on juvenile males and females. To that end, we examined in our established experimental setting whether conditioned male and female animals extinguish contextual fear memory better while in pairs. Taking advantage of the role of oxytocin (OT) in the mediation of extinction memory and social interaction, we also study the effect of antagonizing the OT receptors (OTR) either systemically or in the prefrontal cortex on social interaction-induced effects of fear extinction. The results show that social presence accelerates extinction in males and females as compared to the single condition. Yet, we show differential and opposing effects of an OTR antagonist in both sexes. Whereas in females, the systemic application of an OTR antagonist is associated with impaired extinction, it is associated with enhanced extinction in males. In contrast, prefrontal OT is not engaged in extinction in juvenile males, while is it is critical in females. Previously reported differences in the levels of prefrontal OT between males and females might explain the differences in OT action. These results suggest that even during the juvenile period, critical mechanisms are differently involved in the regulation of fear in males and females.

Isotopic characterization of lifetime movement by two demersal fishes from the northeastern Gulf of Mexico

An understanding of lifetime trophic changes and ontogenetic habitat shifts is essential to the preservation of marine fish species. We used carbon and nitrogen stable isotope values (δ13C and δ15N) recorded within the laminar structure of fish eye lenses, reflecting both diet and location over time, to compare the lifetime trends of 2 demersal mesopredators. TilefishLopholatilus chamaeleonticepsinhabit burrows on the outer continental shelf, which results in exceptional site fidelity. Red grouperEpinephelus morioare spawned on the middle to outer continental shelf, move to the inner shelf for the juvenile period, and return offshore upon sexual maturity. Both species inhabit the eastern Gulf of Mexico, a region with a distinctive offshore-inshore gradient in background δ13C values. Within individual tilefish (n = 36), sequences of δ13C values and δ15N values had strong, positive correlations with eye-lens diameter, and strong correlations between the 2 isotopes (mean Spearman r = 0.86), reflecting an increase in trophic position with growth and little lifetime movement. In red grouper (n = 30), δ15N values positively correlated with eye-lens diameter, but correlations between δ15N and δ13C were weak (mean Spearman r = 0.29), suggesting cross-shelf ontogenetic movements. Linear mixed model results indicated strong relationships between δ15N and δ13C values in tilefish eye lenses but no convergence in the red grouper model. Collectively, these results are consistent with previously established differences in the life histories of the 2 species, demonstrating the potential utility of eye-lens isotope records, particularly for investigating the life histories of lesser-known species.

Peculiarities of the juvenile period of the native Chechen genotypes of willow leaf pear (Pyrus salicifolia Pall.)

The results of the study of the duration of the juvenile period of indigenous Chechen willow leaf pear genotypes (Pyrus salicifolia Pall.) are given in connection with the acceleration of the breeding process and the use of selected forms in pear breeding for high precocity. The studies were carried out in 2016-2019 at OOO “Orchards of Chechnya” in accordance with the Agreement on creative cooperation with the Russian Research Institute of Fruit Crop Breeding. The work was carried out in accordance with generally accepted programs and methods. The objects of the study were one-year and two-year-old pear seedlings obtained from sowing seeds of selected dwarf and low-growing local Chechen forms of willow pear (P. salicifolia Pall.), laying fruit buds on annual growths and seedlings of Caucasian pear (P. caucasica Fed.), 20 500 pcs. of each specie. The aim of the research was to study the potential of precocity of willow pear seedlings and to reveal of selected forms with the greatest degree of this trait. Stratified seeds were sown in the sowing department of the OOO “Orchards of Chechnya” production nursery in April, 2017. The seedlings were grown according to the common technology in dryland conditions on the plot with chestnut soil. The first fl owering of plants was noted in the spring, 2019. As a result of the research, for the first time on a large number of the experimental material it was found that in the off spring of the indigenous Chechen willow leaf pear genotypes, the selection of a little more than 2% of seedlings with a very short juvenile period (2 years) was possible. They are of great interest in accelerating the breeding process and in the selection of new pear varieties with high precocity. 20 willow leaf pear genotypes were selected for the further use in breeding for high precocity and as sources of the trait of short juvenile period.

Regulation of Body Size and Growth Control.

The control of body and organ growth is essential for the development of adults with proper size and proportions, which is important for survival and reproduction. In animals, adult body size is determined by the rate and duration of juvenile growth, which are influenced by the environment. In nutrient-scarce environments in which more time is needed for growth, the juvenile growth period can be extended by delaying maturation, whereas juvenile development is rapidly completed in nutrient-rich conditions. This flexibility requires the integration of environmental cues with developmental signals that govern internal checkpoints to ensure that maturation does not begin until sufficient tissue growth has occurred to reach a proper adult size. The Target of Rapamycin (TOR) pathway is the primary cell-autonomous nutrient sensor, while circulating hormones such as steroids and insulin-like growth factors are the main systemic regulators of growth and maturation in animals. We discuss recent findings in Drosophila melanogaster showing that cell-autonomous environment and growth-sensing mechanisms, involving TOR and other growth-regulatory pathways, that converge on insulin and steroid relay centers are responsible for adjusting systemic growth, and development, in response to external and internal conditions. In addition to this, proper organ growth is also monitored and coordinated with whole-body growth and the timing of maturation through modulation of steroid signaling. This coordination involves interorgan communication mediated by Drosophila insulin-like peptide 8 in response to tissue growth status. Together, these multiple nutritional and developmental cues feed into neuroendocrine hubs controlling insulin and steroid signaling, serving as checkpoints at which developmental progression toward maturation can be delayed. This review focuses on these mechanisms by which external and internal conditions can modulate developmental growth and ensure proper adult body size, and highlights the conserved architecture of this system, which has made Drosophila a prime model for understanding the coordination of growth and maturation in animals.

Boylamanın ve Farklı Boy Kompozisyonlarında yetiştirilmesinin Melez Tilapia (Oreochromis niloticus ♀ X Oreochromis aureus♂) Yavrularının Büyüme Performansları Üzerine etkisi

Su ürünleri yetiştiriciliğinde boylama uygulaması balıklar arasında oluşan boy farkının yarattığı dezavantajlardan korunmak amacıyla yapılır. Bu etkinlikle büyük ve küçük bireyler besleme periyodu sırasında birbirlerinden ayrılırlar. Bu amaçla kurgulanan bu araştırmada Oreochromis niloticus♀ x Oreochromis aureus♂ melezlerinin yetiştiriciliğinde küçük bireylerin büyüme ve besi performansları üzerine sürüye eklenen büyük bireylerin etkilerinin olup olmadığının belirlenmesi amaçlanmıştır. Denemede 0 yaş 1 ile 4 g‘lık melez yavrular fiber tanklara 40 adet/m3 oranında stoklanmış ve 75 gün boyunca yetiştirilmiştir. Deneme grupları, tamamı 1 g‘lık küçük bireylerden oluşan boylanmış bir grup (G1), 1 g ve 2g‘dan oluşan (G2), 1 g ve 3g‘dan oluşan (G3) ve 1 g ve 4g‘dan oluşan (G4) grubundan oluşmuştur. Çalışma sonunda boylamanın tilapia melezlerinin büyümesine pozitif etki etmediği görülmüştür. Buna karşı içinde büyük bireylerin bulunduğu G2 grubundaki küçük bireylerin (18,60±0,33g) diğer gruplardaki küçük bireylerden daha iyi büyüdüğü ortaya çıkmıştır. Bununla birlikte G2 grubu diğer gruplardan daha iyi bir (1,39±0,05) YDO‘na ulaşmıştır. En iyi ekonomik dönüşüm oranı yine G2 grubunda (11,12±0,75) elde edilmiştir. Sonuç olarak farklı boydaki bireylerle yapılan yetiştiricilik uygulamasının melez tilapia yavrularının gelişimine pozitif etki yarattığı, özellikle 1+2 g şeklinde stoklandıklarında rekabet ortamının geliştiği ve bu durumun yetiştiricilik ekonomisine olumlu yönde etki ettiği gözlemlenmiştir.

Major QTL with pleiotropic effects controlling time of leaf budburst and flowering-related traits in walnut (Juglans regia L.)

Breeding studies in walnut (Juglans regia L.) are usually time consuming due to the long juvenile period and therefore, this study aimed to determine markers associated with time of leaf budburst and flowering-related traits by performing a genome-wide association study (GWAS). We investigated genotypic variation and its association with time of leaf budburst and flowering-related traits in 188 walnut accessions. Phenotypic data was obtained from 13 different traits during 3 consecutive years. We used DArT-seq for genotyping with a total of 33,519 (14,761 SNP and 18,758 DArT) markers for genome-wide associations to identify marker underlying these traits. Significant correlations were determined among the 13 different traits. Linkage disequilibrium decayed very quickly in walnut in comparison with other plants. Sixteen quantitative trait loci (QTL) with major effects (R2 between 0.08 and 0.23) were found to be associated with a minimum of two phenotypic traits each. Of these QTL, QTL05 had the maximum number of associated traits (seven). Our study is GWAS for time of leaf budburst and flowering-related traits in Juglans regia L. and has a strong potential to efficiently implement the identified QTL in walnut breeding programs.

Within-field variability of plant and canopy traits of sugar beet and their relation to individual root mass during harvest

The present study reports on research results obtained in the years 2014–2015 on two sugar beet production plantations in Central Poland. The purpose of any production is to obtain homogeneous canopy with the plants of demanded morphological and qualitative traits. The aim of the research was the assessment of the range and scale of plant variability in sugar beet canopy and impact of investigated plant and canopy traits (number of days from sowing to emergence, development stage of plants in the juvenile period, the plant living area, the location centrality index) to the final root mass at harvest time. Variability of investigated plant and canopy traits was evaluated using the variation coefficient, while the impact of these traits on the final root mass was assessed using the analysis of multiple linear regression. The obtained results show that sugar beet canopy reveals large, within-field variability in the investigated traits. The established relationship between final root mass during harvest and the canopy traits indicates that to obtain a large final root mass of individual plants during harvest, the most important is fast and even plant emergence, as well as the rapid development of plants in the juvenile period. At both production plantations, the impact of the living area of individual plants on the final mass of their roots was significant. However, no significant effect of the location centrality index on plant living area and the final root mass was found.

Screening and identification of miRNAs related to sexual differentiation of strobili in Ginkgo biloba by integration analysis of small RNA, RNA, and degradome sequencing

BackgroundGinkgo biloba, a typical dioecious plant, is a traditional medicinal plant widely planted. However, it has a long juvenile period, which severely affected the breeding and cultivation of superior ginkgo varieties.ResultsIn order to clarify the complex mechanism of sexual differentiation in G. biloba strobili. Here, a total of 3293 miRNAs were identified in buds and strobili of G. biloba, including 1085 known miRNAs and 2208 novel miRNAs using the three sequencing approaches of transcriptome, small RNA, and degradome. Comparative transcriptome analysis screened 4346 and 7087 differentially expressed genes (DEGs) in male buds (MB) _vs_ female buds (FB) and microstrobilus (MS) _vs_ ovulate strobilus (OS), respectively. A total of 6032 target genes were predicted for differentially expressed miRNA. The combined analysis of both small RNA and transcriptome datasets identified 51 miRNA-mRNA interaction pairs that may be involved in the process of G. biloba strobili sexual differentiation, of which 15 pairs were verified in the analysis of degradome sequencing.ConclusionsThe comprehensive analysis of the small RNA, RNA and degradome sequencing data in this study provided candidate genes and clarified the regulatory mechanism of sexual differentiation of G. biloba strobili from multiple perspectives.

Exposure to benzo(a)pyrene from juvenile period to peripubertal impairs male reproductive parameters in adult rats

Benzo(a)pyrene (BaP) is a persistent organic pollutant and endocrine disruptor that can compromise the steroidogenesis process by interacting with the StAR protein, causing adverse effects on male reproduction. However, consequences of prepubertal BaP exposure and its impacts on adult life are yet unknown. This study investigated the effects of BaP exposure from the juvenile period to peripubertal on reproductive parameters in adult male rats. Males were exposed to 0; 0.1; 1 or 10 μg/kg/day of BaP from post-natal (PND) 23 to PND 53 (by gavage). The lowest dose of BaP was able to compromise the male copulatory behavior, as evidenced by the delay in the first mount, intromission and ejaculation. Furthermore, BaP-treated groups showed lower sperm quality (disrupted motility and morphology) and quantity, reduced relative weights of the thyroid and seminal gland. Serum testosterone levels and the Leydig cells nuclei volume were decreased by BaP exposure whereas the StAR expression was increased. Histopathological changes in the testis also were detected in the males exposed to BaP. These results showed that prepubertal BaP-exposure adversely influenced the male reproductive system in the adult life, indicating that a comprehensive risk assessment of BaP-exposure on prepubertal period is necessary.

Age and sex differences in juvenile bonobos in party associations with their mothers at Wamba.

Mothers are the most fundamental individuals for the survival and development of their immature offspring. Sex-biased dispersal has an effect on strong and long-lasting social bonding between mothers and their philopatric offspring. Nepotistic relationships are often seen in species with male-biased dispersal but less frequently in species with female-biased dispersal. Bonobos are unique among female-biased dispersal primates in that the females are codominant with males, exert influence on the mating opportunities of their mature sons, and tolerate each other regardless of relatedness. Few studies on bonobos have examined sex differences in social relationships between juveniles and their mothers, and how this relates to mother-son and female-female cooperative relationships amongst adults. We investigated whether the association index of juveniles with their mothers changed with age depending on the sex of the juveniles in parties of bonobos at Wamba, the Democratic Republic of the Congo. We found that female bonobos had decreased party associations with their mothers prior to their emigration from the natal group, while male bonobos maintained relatively high party associations with their mothers. These results indicate that sex differences that emerge during the juvenile period in bonobos in their spatial relationships with their mothers differ from previous findings on chimpanzees, spider monkeys, and muriquis, in which philopatric sons tend to spend less time in proximity to their mothers and disperse earlier than, or at a similar age to, daughters. The contrasts between bonobos and other primate species suggest that the high social status of female bonobos relative to that of males mayfacilitate the extension of maternal support for their philopatric sons, and that high tolerance among unrelated females mayenable the spatial independence of daughters from their mothers at an earlier stage.

Accumulation and distribution of radionuclides in higher aquatic plants during the vegetation period

The long-term observations of the dynamics of 90Sr and 137Cs concentration, as well as the physicochemical forms of these radionuclides in 10 species of higher aquatic plants during the vegetation period of Glyboke Lake in the Chornobyl Exclusion Zone were presented. The accumulation of radionuclides depends on the influence of environmental factors and species characteristics of the studied plants. It has been shown that the accumulation of 90Sr and 137Cs by plants mainly occurs in accordance with the physiological stages of their development. Under conditions of intensive growth and accumulation of biomass in the juvenile period, plants disproportionately uptake 137Cs from the environment; during the seed ripening period at the stage of aging, plants mainly accumulate 90Sr, as evidenced by the non-correlation of this radionuclide concentration in water and plants in the considered periods. The specific features of the accumulation of radionuclides by plants were studied by the method of analysis of physicochemical forms, which consists in the sequential extraction of radionuclides from plant preparations and makes it possible to quantitatively investigate potentially exchange and fixed forms. The analysis of physicochemical forms confirmed the patterns of seasonal distribution of radionuclides, as well as their accumulation in cells, tissues and in the whole plant obtained from long-term observations.