Ova Research Articles

Identification and pathogenicity of Aeromonas veronii isolated from sexually mature female Hypophthalmichthys molitrix

An outbreak of bacterial septicemia in female silver carp Hypophthalmichthys molitrix, which caused significant death of the fish in the Yantian Reservoir, was investigated. The pathogen was isolated from diseased fish and identified as Aeromonas veronii utilizing biochemical characteristics and molecular methods analyses. An artificial infection experiment indicated that the strain caused 100% mortality of juvenile silver carp and mature female fish with eggs but no death of the mature male fish. Silver carp challenged with A. veronii showed similar clinical signs with naturally infected fish. The histopathological study revealed that A. veronii infection caused the increment of hemosiderin granules and the vacuole formation in tissues of the spleen and livers, as well as the collapse, deformation, and disintegration of egg cells. The ACP, AKP, and CAT enzyme activities in the serum of both naturally and artificially infected silver carp were decreased significantly with the severe infection. In this study, A. veronii was isolated and identified as the primary bacterial pathogen causing the mass death of sexually mature female silver carp with eggs in Yantian Reservoir.

Chiral flows can induce neck formation in viscoelastic surfaces

The cell cortex is an active viscoelastic self-deforming sheet at the periphery of animal cells. It constricts animal cells during cell division. For some egg cells, the actomyosin cortex was shown to exhibit counter-rotating chiral flows along the axis of division. Such chiral surface flows were shown to contribute to spatial rearrangements and left-right symmetry breaking in developing organisms. In spite of this prospective biological importance, the effect of chiral forces on the flows and emergent shape dynamics of a deformable surface are completely unknown. To shed a first light on that matter, we present here a numerical study of an axisymmetric viscoelastic surface embedded in a viscous fluid. We impose a generic counter-rotating force field on this surface and study the resulting chiral flow field and shape dynamics for various surface mechanical parameters. Notably, we find that the building of a neck, as is observed during cell division, occurs if the surface contains a strong shear elastic component. Furthermore, we find that a large areal relaxation time results in flows towards the equator of the surface. These flows assist the transport of a surface concentration during the formation of a contractile ring. Accordingly, we show that chiral forces by themselves can drive pattern formation and stabilise contractile rings at the equator. These results provide first mechanistic evidence that chiral flows can play a significant role to orchestrate cell division.

Making Futures by Freezing Life: Ambivalent Temporalities of Cryopreservation Practices

The preservation of biological matter at extremely low temperatures has gained increasing importance in a broad range of life science fields in recent years. Social and cultural studies of cryotechnologies have often likened the freezing of life to a stillstand of time. This special issue explores the argument that cryotechnologies require us to rethink time and temporality more broadly: freezing does not simply equate to an interruption of the “natural” course of time. Covering diverse types of freezing practices and biological materials—egg cells, cord blood, lab mice, and breast milk—the articles in this issue inquire empirically and theoretically into different ways in which cryotechnologies contribute in making particular pasts, presents, and futures. In engaging with cryopreservation, we have to take into account the complex, sometimes contradictory, pathways in which life, death, and time are made and remade through freezing.

An Overview of the Female Reproductive System: A Narrative Literature Review

The female reproductive system is a biological system that is responsible for producing, transporting, and storing eggs and facilitating the meeting between eggs and sperm for fertilization. The female reproductive system consists of internal and external organs. This literature review aimed to describe the female reproductive system. Internal organs include the ovaries (ovaries), fallopian tubes (oviducts), uterus (womb), cervix (cervix), and vagina. The ovary is the main female reproductive organ. The two main functions of the ovaries are the secretion of female sex hormones and the development and release of female gametes, or ova. The almond-shaped ovaries are located on either side of the uterus and are supported and supported by the halves mesovarium of the broad, ovarian, and suspensory ligaments. The female reproductive system is also influenced by reproductive hormones such as estrogen, progesterone, and gonadotropins which are produced by the pituitary gland and ovaries.

Prospective of Indole-3-Acteic Acid (IAA) and Endophytic Microbe Bacillus subtilis Strain SSA4 in Paddy Seedlings Development and Ascorbate–Glutathione (AsA-GSH) Cycle Regulation to Mitigate NaCl Toxicity

Plant growth promoting endophytes significantly affected plant health. The present study demonstrates effect of endophytic isolate Bacillus subtilis strain SSA4 and exogenous Indole-3-acetic acid (IAA) on paddy seedlings growth parameters, photosynthetic pigments, photosynthesis, leaf gas exchange parameters, respiration, oxidative stress biomarkers and Ascorbate-Glutathione (AsA-GSH) cycle under different NaCl (0-300mM) stresses. The Bacillus subtilis SSA4 was identified by 16S r-RNA gene sequence analyses and NCBI BLASTn tools. The B. subtilis SSA4 tolerated 1100mM NaCl and produced IAA (42.15µgm/L) at 300mM NaCl stress. The paddy genotype (HUR 917) treated with exogenous IAA (21µgm/L) and B. subtilis strain SSA4 egg cell based bioformulation was significantly affected seedlings physiology and biochemistry at lower (150mM) and higher (300mM) NaCl doses. In conclusion, co-inoculation found as effective green tool to mitigating salinity stress in paddy seedlings.

Creation of a watermelon haploid inducer line via ClDMP3-mediated single fertilization of the central cell.

The use of doubled haploids is one of the most efficient breeding methods in modern agriculture. Irradiation of pollen grains has been shown to induce haploids in cucurbit crops, possibly because it causes preferential fertilization of the central cell over the egg cell. Disruption of the DMP gene is known to induce single fertilization of the central cell, which can lead to the formation of haploids. In the present study, a detailed method of creating a watermelon haploid inducer line via ClDMP3 mutation is described. The cldmp3 mutant induced haploids in multiple watermelon genotypes at rates of up to 1.12%. These haploids were confirmed via fluorescent markers, flow cytometry, molecular markers, and immuno-staining. The haploid inducer created by this method has the potential to greatly advance watermelon breeding in the future.

2022 Winners: Kathleen Scheffler, Federica Giannini and Tom Lemonnier

2022 Winners: Kathleen Scheffler, Federica Giannini and Tom Lemonnier

50 years of sperm cell isolations: from structural to omic studies.

The fusion of male and female gametes is a fundamental process in the perpetuation and diversification of species. During the last 50 years, significant efforts have been made to isolate and characterize sperm cells from flowering plants, and to identify how these cells interact with female gametes to achieve double fertilization. The first techniques and analytical approaches not only provided structural and biochemical characterizations of plant sperm cells but also paved the way for in vitro fertilization studies. Further technological advances then led to unique insights into sperm biology at transcriptomic, proteomic and epigenetic level. Starting with a historical overview of sperm cell isolation techniques, we provide examples of how these contributed to create our current knowledge of sperm cell biology, and point out remaining challenges.

Increased male investment in sperm competition results in reduced maintenance of gametes.

Male animals often show higher mutation rates than their female conspecifics. A hypothesis for this male bias is that competition over fertilization of female gametes leads to increased male investment into reproduction at the expense of maintenance and repair, resulting in a trade-off between male success in sperm competition and offspring quality. Here, we provide evidence for this hypothesis by harnessing the power of experimental evolution to study effects of sexual selection on the male germline in the seed beetle Callosobruchus maculatus. We first show that 50 generations of evolution under strong sexual selection, coupled with experimental removal of natural selection, resulted in males that are more successful in sperm competition. We then show that these males produce progeny of lower quality if engaging in sociosexual interactions prior to being challenged to surveil and repair experimentally induced damage in their germline and that the presence of male competitors alone can be enough to elicit this response. We identify 18 candidate genes that showed differential expression in response to the induced germline damage, with several of these previously implicated in processes associated with DNA repair and cellular maintenance. These genes also showed significant expression changes across sociosexual treatments of fathers and predicted the reduction in quality of their offspring, with expression of one gene also being strongly correlated to male sperm competition success. Sex differences in expression of the same 18 genes indicate a substantially higher female investment in germline maintenance. While more work is needed to detail the exact molecular underpinnings of our results, our findings provide rare experimental evidence for a trade-off between male success in sperm competition and germline maintenance. This suggests that sex differences in the relative strengths of sexual and natural selection are causally linked to male mutation bias. The tenet advocated here, that the allocation decisions of an individual can affect plasticity of its germline and the resulting genetic quality of subsequent generations, has several interesting implications for mate choice processes.

Transcriptomic Analysis of Hormone Signal Transduction, Carbohydrate Metabolism, Heat Shock Proteins, and SCF Complexes before and after Fertilization of Korean Pine Ovules

The fertilization process is a critical step in plant reproduction. However, the mechanism of action and mode of regulation of the fertilization process in gymnosperms remain unclear. In this study, we investigated the molecular regulatory networks involved in the fertilization process in Korean pine ovules through anatomical observation, physiological and biochemical assays, and transcriptome sequencing technology. The morphological and physiological results indicated that fertilization proceeds through the demise of the proteinaceous vacuole, egg cell division, and pollen tube elongation. Auxin, cytokinin, soluble sugar, and soluble starch contents begin to decline upon fertilization. Transcriptomic data analysis revealed a large number of differentially expressed genes at different times before and after fertilization. These genes were primarily involved in pathways associated with plant hormone signal transduction, protein processing in the endoplasmic reticulum, fructose metabolism, and mannose metabolism. The expression levels of several key genes were further confirmed by qRT-PCR. These findings represent an important step towards understanding the mechanisms underlying morphological changes in the Korean pine ovule during fertilization, and the physiological and transcriptional analyses lay a foundation for in-depth studies of the molecular regulatory network of the Korean pine fertilization process.

New insights into the role of microheterogeneity of ZP3 during structural maturation of the avian equivalent of mammalian zona pellucida.

The egg coat including mammalian zona pellucida (ZP) and the avian equivalent, i.e., inner-perivitelline layer (IPVL), is a specialized extracellular matrix being composed of the ZP glycoproteins and surrounds both pre-ovulatory oocytes and ovulated egg cells in vertebrates. The egg coat is well known for its potential importance in both the reproduction and early development, although the underlying molecular mechanisms remain to be fully elucidated. Interestingly, ZP3, one of the ZP-glycoprotein family members forming scaffolds of the egg-coat matrices with other ZP glycoproteins, exhibits extreme but distinctive microheterogeneity to form a large number of isoelectric-point isoforms at least in the chicken IPVL. In the present study, we performed three-dimensional confocal imaging and two-dimensional polyacrylamide-gel electrophoresis (2D-PAGE) of chicken IPVLs that were isolated from the ovarian follicles at different growth stages before ovulation. The results suggest that the relative proportions of the ZP3 isoforms are differentially altered during the structural maturation of the egg-coat matrices. Furthermore, tandem mass spectrometry (MS/MS) analyses and ZP1 binding assays against separated ZP3 isoforms demonstrated that each ZP3 isoform contains characteristic modifications, and there are large differences among ZP3 isoforms in the ZP1 binding affinities. These results suggest that the microheterogeneity of chicken ZP3 might be regulated to be associated with the formation of egg-coat matrices during the structural maturation of chicken IPVL. Our findings may provide new insights into molecular mechanisms of egg-coat assembly processes.

Aging of common carp (Cyprinus carpio L.) sperm induced by short-term storage does not alter global DNA methylation and specific histone modifications in offspring

Short-term storage of sperm is a useful tool to synchronize the availability of male and female gametes for fertilization in a hatchery. Induced aging by short-term storage has been shown to affect fish spermatozoa phenotypes including morphology and motility kinetics. However, its effects on epigenetics of sperm and the resulting embryos have not been investigated. In the present study, sperm of common carp (Cyprinus carpio) was stored in vivo and/or in vitro using an extender, and spermatozoa motility kinetics, viability, and epigenetics were analyzed. We observed that spermatozoa motility and velocity decreased following in vivo and/or in vitro storage from 3 to 6.5 days, but spermatozoa viability remained stable. At the same time, global DNA methylation, DNA hydroxymethylation, and specific histone acetylation and methylation were not affected by sperm aging. Further analysis showed no variation in global DNA methylation during embryogenesis when short-term stored sperm in the extender was used for fertilization compared with embryos produced from fresh sperm. The results suggest the reliability of short-term storage of sperm using an extender in fertilization and the production of the next generation of embryos. However, larval growth and performance need to be elucidated for these fish. This study has shed light on the potential application of extenders in storage of sperm in common carp breeding programs to manage selection, genomic manipulation and genetic resources conservation.

Exploring novel polytubey reproduction pathways utilizing cumulative genetic tools.

In the anthers and ovaries of flowers, pollen grains and embryo sacs are produced with uniform cell compositions. This stable gametogenesis enables elaborate interactions between male and female gametophytes after pollination, forming the highly successful sexual reproduction system in flowering plants. As most ovules are fertilized with a single pollen tube, the resulting genome set in the embryo and endosperm is determined in a single pattern by independent fertilization of the egg cell and central cell by two sperm cells. However, if ovules receive four sperm cells from two pollen tubes, the expected options for genome sets in the developing seeds would more than double. In wild-type Arabidopsis thaliana plants, around 5% of ovules receive two pollen tubes. Recent studies have elucidated the abnormal fertilization in supernumerary pollen tubes and sperm cells related to polytubey, polyspermy, heterofertilization, and fertilization recovery. Analyses of model plants have begun to uncover the mechanisms underlying this new pollen tube biology. Here, we review unusual fertilization phenomena and propose several breeding applications for flowering plants. These arguments contribute to the remodeling of plant reproduction, a challenging concept that alters typical plant fertilization by utilizing the current genetic toolbox.

Expression profiles of meiotic genes in male vs. female gonads and gametes: Insights into fertility issues.

Gametes are specialized cells that, at fertilization, give rise to a totipotent zygote capable of generating an entire organism. Female and male germ cells undergo meiosis to produce mature gametes; however, sex-specific events of oogenesis and spermatogenesis contribute to specific roles of gametes in reproductive issues. We investigate the differential gene expression (DGE) of meiosis-related genes in human female and male gonads and gametes in normal and pathological conditions. The transcriptome data for the DGE analysis was obtained through the Gene Expression Omnibus repository, comprising human ovary and testicle samples of the prenatal period and adulthood, additionally to male (non-obstructive azoospermia (NOA) and teratozoospermia), and female (polycystic ovary syndrome (PCOS) and advanced maternal age) reproductive conditions. Gene ontology terms related to meiosis were associated with 678 genes, of which 17 genes in common were differentially expressed between the testicle and ovary during the prenatal period and adulthood. Except for SERPINA5 and SOX9, the 17 meiosis-related genes were downregulated in the testicle during the prenatal period and upregulated in adulthood compared to the ovary. No differences were observed in the oocytes of PCOS patients; however, meiosis-related genes were differentially expressed according to the patient's age and maturity of the oocyte. In NOA and teratozoospermia, 145 meiosis-related genes were differentially expressed in comparison to the control, including OOEP; despite no recognized role in male reproduction, OOEP was co-expressed with genes related to male fertility. Taking together, these results shed light on potential genes that might be relevant to comprehend human fertility disorders.

A review : The Relationships Between Ovary Disease and Tumor Marker

The ovary is an organ found in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary found on each side of the body. The ovaries also secrete hormones that play a role in the menstrual cycle and fertility. The ovary progresses through many stages beginning in the prenatal period through menopause. It is also an endocrine gland because of the various hormones that it secrete. 
 The ovary starts secreting more and more hormones at puberty. The hormones trigger the development of secondary sex traits. Starting with adolescence, the ovary undergoes structural and functional changes. The ability of the ovaries to control hormones makes them crucial to fertility and conception. A number of feedback mechanisms are stimulated when egg cells, or oocytes, are expelled from the Fallopian tube, which changes the hormone levels in the body. 
 Ovaries release progesterone, estrogen, testosterone, and inhibin at sexual maturity. The adrenal glands and ovaries in women create 50% of the body's testosterone, which is then immediately delivered into the bloodstream. Estrogen is in charge of the maturation and maintenance of the reproductive organs in their mature functional state, as well as the appearance of secondary sex characteristics in females during puberty. The uterus and mammary glands are prepared for pregnancy and breastfeeding, respectively, by progesterone. Progesterone and estrogen work together to promote endometrial changes associated with the menstrual cycle.

Zygote structure enables pluripotent shape-transforming deployable structure.

We propose an algorithmic framework of a pluripotent structure evolving from a simple compact structure into diverse complex 3D structures for designing the shape-transformable, reconfigurable, and deployable structures and robots. Our algorithmic approach suggests a way of transforming a compact structure consisting of uniform building blocks into a large, desired 3D shape. Analogous to a fertilized egg cell that can grow into a preprogrammed shape according to coded information, compactly stacked panels named the zygote structure can evolve into arbitrary 3D structures by programming their connection path. Our stacking algorithm obtains this coded sequence by inversely stacking the voxelized surface of the desired structure into a tree. Applying the connection path obtained by the stacking algorithm, the compactly stacked panels named the zygote structure can be deployed into diverse large 3D structures. We conceptually demonstrated our pluripotent evolving structure by energy-releasing commercial spring hinges and thermally actuated shape memory alloy hinges, respectively. We also show that the proposed concept enables the fabrication of large structures in a significantly smaller workspace.

Analysis of the Elemental Composition of Gonads, Gametes and Larvae of the Mussel <i>Mytilus galloprovincialis</i> in the Spawning Period

In this work, we studied the elemental composition of gonads, eggs, sperm and larvae of the mussel Mytilus galloprovincialis during spawning, when the contents of biologically active compounds and minerals are maximal. A comparative analysis of the contents showed that the elements are involved in the mussel gametogenesis in different pathways. There were significant differences in the contents of Li, B, Mg, Si, P, K, Ca, V, Cr, Mn, Fe, Co, Ni, Zn, Ge, As, Se, Br, Rb, Sr, Mo, Pd, Sn, I, Ba and Ce in male and female gonads before and after spawning, gametes and larvae of mussels. It is likely that some of the listed elements are not only passively accumulated in the mollusk body, but are also essential, being directly involved in the reproduction process. Most of significant differences in the element contents were found between eggs and larvae and between male gonads before spawning and sperm. By spawning, mussel gonads accumulated mainly p- and d-elements, apparently due to the ability of their ions to form complexes and, consequently, to be included in the structure of enzymes. The contents of B, Mg, Si, P, K, Ca, Cr, Mn, Fe, Cu, Zn, As, Se, Br, Sr and Ba in male and female gonads, gametes and larvae were an order or several orders of magnitude higher than those of other elements. The contents of Ca, Fe, Sr, Sn and I in mussel larvae were significantly higher than in gonads and gametes. Sn is a technological hydropollutant, and thus, larvae can serve as a bioindicator of the aquatic environment pollution with this element. The data obtained are of practical interest for improving the biotechnology of reproduction of marine hydrobionts and obtaining functional products based on them, which is important for the optimization of aquaculture management and for addressing human health-related issues.

Environmental contaminants, endocrine disruption, and transgender: Can "born that way" in some cases be toxicologically real?

Gender is viewed by many as strictly binary based on a collection of body traits typical of a female or male phenotype, presence of a genotype that includes at least one copy of a Y chromosome, or ability to produce either egg or sperm cells. A growing non-binary view is that these descriptors, while compelling, may nonetheless fail to accurately capture an individual's true gender. The position of the American Psychological Association (APA) agrees with this view and is that transgender people are a defendable and real part of the human population. The considerable diversity of transgender expression then argues against any unitary or simple explanations, however, prenatal hormone levels, genetic influences, and early and later life experiences have been suggested as playing roles in development of transgender identities. The present review considers existing and emerging toxicologic data that may also support an environmental chemical contribution to some transgender identities, and suggest the possibility of a growing nonbinary brain gender continuum in the human population.

Fate Decisions of Chicken Primordial Germ Cells (PGCs): Development, Integrity, Sex Determination, and Self-Renewal Mechanisms.

Primordial germ cells (PGCs) are precursor cells of sperm and eggs. The fate decisions of chicken PGCs in terms of their development, integrity, and sex determination have unique features, thereby providing insights into evolutionary developmental biology. Additionally, fate decisions in the context of a self-renewal mechanism have been applied to establish culture protocols for chicken PGCs, enabling the production of genome-edited chickens and the conservation of genetic resources. Thus, studies on the fate decisions of chicken PGCs have significantly contributed to both academic and industrial development. Furthermore, studies on fate decisions have rapidly advanced owing to the recent development of essential research technologies, such as genome editing and RNA sequencing. Here, we reviewed the status of fate decisions of chicken PGCs and provided insight into other important research issues that require attention.

Single-Cell Transcriptomics To Define Plasmodium falciparum Stage Transition in the Mosquito Midgut.

Malaria inflicts the highest rate of morbidity and mortality among the vector-borne diseases. The dramatic bottleneck of parasite numbers that occurs in the gut of the obligatory mosquito vector provides a promising target for novel control strategies. Using single-cell transcriptomics, we analyzed Plasmodium falciparum development in the mosquito gut, from unfertilized female gametes through the first 20 h after blood feeding, including the zygote and ookinete stages. This study revealed the temporal gene expression of the ApiAP2 family of transcription factors and of parasite stress genes in response to the harsh environment of the mosquito midgut. Further, employing structural protein prediction analyses, we found several upregulated genes predicted to encode intrinsically disordered proteins (IDPs), a category of proteins known for their importance in regulation of transcription, translation, and protein-protein interactions. IDPs are known for their antigenic properties and may serve as suitable targets for antibody- or peptide-based transmission suppression strategies. In total, this study uncovers the P. falciparum transcriptome from early to late parasite development in the mosquito midgut, inside its natural vector, which provides an important resource for future malaria transmission-blocking initiatives. IMPORTANCE The malaria parasite Plasmodium falciparum causes more than half a million deaths per year. The current treatment regimen targets the symptom-causing blood stage inside the human host. However, recent incentives in the field call for novel interventions to block parasite transmission from humans to the mosquito vector. Therefore, we need to better understand the parasite biology during its development inside the mosquito, including a deeper understanding of the expression of genes controlling parasite progression during these stages. Here, we have generated single-cell transcriptome data, covering P. falciparum's development, from gamete to ookinete inside the mosquito midgut, uncovering previously untapped parasite biology, including a repertoire of novel biomarkers to be explored in future transmission-blocking efforts. We anticipate that our study provides an important resource, which can be further explored to improve our understanding of the parasite biology as well as aid in guiding future malaria intervention strategies.