Nitrogen-fixing organelle in a marine alga

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."

Effects of foetal size, sex and developmental stage on adaptive transcriptional responses of skeletal muscle to intrauterine growth restriction in pigs

Intrauterine growth restriction (IUGR) occurs both in humans and domestic species. It has a particularly high incidence in pigs, and is a leading cause of neonatal morbidity and mortality as well as impaired postnatal growth. A key feature of IUGR is impaired muscle development, resulting in decreased meat quality. Understanding the developmental origins of IUGR, particularly at the molecular level, is important for developing effective strategies to mitigate its economic impact on the pig industry and animal welfare. The aim of this study was to characterise transcriptional profiles in the muscle of growth restricted pig foetuses at different gestational days (GD; gestational length ~ 115 days), focusing on selected genes (related to development, tissue injury and metabolism) that were previously identified as dysregulated in muscle of GD90 fetuses. Muscle samples were collected from the lightest foetus (L) and the sex-matched foetus with weight closest to the litter average (AW) from each of 22 Landrace x Large White litters corresponding to GD45 (n = 6), GD60 (n = 8) or GD90 (n = 8), followed by analyses, using RT-PCR and protein immunohistochemistry, of selected gene targets. Expression of the developmental genes, MYOD, RET and ACTN3 were markedly lower, whereas MSTN expression was higher, in the muscle of L relative to AW littermates beginning on GD45. Levels of all tissue injury-associated transcripts analysed (F5, PLG, KNG1, SELL, CCL16) were increased in L muscle on GD60 and, most prominently, on GD90. Among genes involved in metabolic regulation, KLB was expressed at higher levels in L than AW littermates beginning on GD60, whereas both IGFBP1 and AHSG were higher in L littermates on GD90 but only in males. Furthermore, the expression of genes specifically involved in lipid, hexose sugar or iron metabolism increased or, in the case of UCP3, decreased in L littermates on GD60 (UCP3, APOB, ALDOB) or GD90 (PNPLA3, TF), albeit in the case of ALDOB this only involved females. In conclusion, marked dysregulation of genes with critical roles in development in L foetuses can be observed from GD45, whereas for a majority of transcripts associated with tissue injury and metabolism differences between L and AW foetuses were apparent by GD60 or only at GD90, thus identifying different developmental windows for different types of adaptive responses to IUGR in the muscle of porcine foetuses.

Nanoplastics impair growth and nitrogen fixation of marine nitrogen-fixing cyanobacteria

Nanoplastics pollution is a growing environmental problem worldwide. Recent research has demonstrated the toxic effects of nanoplastics on various marine organisms. However, the influences of nanoplastics on marine nitrogen-fixing cyanobacteria, a critical nitrogen source in the ocean, remained unknown. Here, we report that nanoplastics exposure significantly reduced growth, photosynthetic, and nitrogen fixation rates of Crocosphaera watsonii (a major marine nitrogen-fixing cyanobacterium). Transcriptomic analysis revealed that nanoplastics might harm C. watsonii via downregulation of photosynthetic pathways and DNA damage repair genes, while genes for respiration, cell damage, nitrogen limitation, and iron (and phosphorus) scavenging were upregulated. The number and size of starch grains and electron-dense vacuoles increased significantly after nanoplastics exposure, suggesting that C. watsonii allocated more resources to storage instead of growth under stress. We propose that nanoplastics can damage the cell (e.g., DNA, cell membrane, membrane-bound transporters, etc.), inhibit N2 and CO2 fixation, and hence lead to nutrient limitation and impaired growth. Our findings suggest the possibility that nanoplastics pollution could reduce the new nitrogen input and hence affect the productivity in the ocean. The impact of nanoplastics on marine nitrogen fixation and productivity should be considered when predicting the ecosystem response and biogeochemical cycling in the changing ocean.

Noctiluca scintillans bloom alters the composition and carbohydrate utilization of associated bacterial community and enriches potential pathogenic bacterium Vibrio anguillarum

Noctiluca scintillans (red) is a widely distributed heterotrophic dinoflagellate and a prominent red tide forming species. This study investigated the effects of Noctiluca blooms on marine microbial diversity and functionality using multi-omics approaches. Our findings revealed significant differences in the community composition of Noctiluca-associated bacteria compared to those associated with autotrophic plankton and free-living bacteria in the surrounding seawater. The dominant bacterial groups within the Noctiluca-associated community shifted at various bloom stages, which could be attributed to changes in prey composition of Noctiluca. During the non-bloom stage, Burkholderiaceae, Carnobacteriaceae, and Pseudomonadaceae dominated the community, while Vibrionaceae became dominant during the bloom stage, and Saprospiraceae, Crocinitomicaceae, and Pirellulaceae thrived during the post-bloom stage. Compared to the non-bloom stage, Noctiluca-associated bacterial community at the bloom stage exhibited significant down-regulation of genes related to complex carbohydrate metabolism, while up-regulation of genes related to glucose transportation and utilization. Furthermore, we identified Vibrio anguillarum, a potential pathogenic bacterium to marine fish, as a major component of the Vibrionaceae family during the bloom stage. The occurrence of V. anguillarum associated with Noctiluca blooms may be attributed to the increased availability of its preferred carbon sources and its high capabilities in glucose transportation, motility and chemotaxis. Moreover, the presence of Vibrio infection genes (hap, hlyA, rtxA) encoding vibriolysin, hemolysin, and RTX (Repeats-in-toxin) toxin in the V. anguillarum genome, with the hap gene showing high expression levels during Noctiluca blooms, indicates an elevated risk of infection. This study underscores the unique composition of the bacterial community associated with red tide forming heterotrophic dinoflagellates and suggests that Noctiluca cells may serve as reservoirs and vectors for pathogenic bacteria, potentially posing a threat to fish-farming and the health of other marine organisms.

Active degradation-nitrification microbial assemblages in the hypoxic zone in a subtropical estuary

In 2017 summer, we observed widespread bottom hypoxia at the lower estuary of the Pearl River estuary (PRE). Our previous study noticed that AOA and bacteria were highly abundant and clustered within the hypoxia zone. Moreover, nitrification and respiration rates were also evidently higher in these hypoxic waters. These observations prompt us to investigate whether these two oxygen-consuming microorganisms have symbiotic relationships and whether specific groups consistently coexist and form ecological-meaningful associations. In this study, we use network analysis to investigate the presence and active communities (DNA-RNA) based on bacterial and AOA communities sequencing (inferred from the 16S rRNA and amoA gene, respectively) to gain more insight into ecological-meaningful associations. We observed a highly diverse and active bacterial community in the hypoxia zone. The RNA networks were more modulized than the corresponding DNA networks, indicating that the active communities were better parsed into functional microbial assemblages. The network topology revealed that Gammaproteobacteria, Bacteroidetes (Flavobacteriales), Alphaproteobacteria (Rhodobacterales and Rhodospirillales), Marinimicrobia, Cyanobacteria (Synechococcales), and AOA sublineages were module hubs and connectors, indicating that they were the keystone taxa of the microbial communities. The hub-subnetwork further showed robust co-occurrence between Gammaproteobacteria, Bacteroidetes (Flavobacteriales), Alphaproteobacteria (Rhodobacterales and Rhodospirillales), Marinimicrobia with AOA sublineages, and Nitrospinae (presumably NOB) reflecting the formation of Degradation-Nitrification (sequential oxidation of Organic matter degradation to ammonia, then nitrate) microbial assemblage in the hypoxia zone. The subnetworks revealed AOA ecotype-specific modularization and niche partitioning of different AOA sublineages. Interestingly, the recurring co-occurrence of nitrifiers assemblage in the RNA subnetworks (SCM1-like-II (AOA) and Nitrospinae OTUs (NOB) suggests an active interaction via nitrite exchange. The Degradation-Nitrification microbial assemblage may contribute substantially to the oxygen consumption in the hypoxia formation in PRE. Our results provide new insight into the functional microbial assemblages, which is worth further investigation on their ecological implication in estuarine waters.

Non-cyanobacterial diazotrophs: global diversity, distribution, ecophysiology, and activity in marine waters

Biological dinitrogen (N2) fixation supplies nitrogen to the oceans, supporting primary productivity, and is carried out by some bacteria and archaea referred to as diazotrophs. Cyanobacteria are conventionally considered to be the major contributors to marine N2 fixation, but non-cyanobacterial diazotrophs (NCDs) have been shown to be distributed throughout ocean ecosystems. However, the biogeochemical significance of marine NCDs has not been demonstrated. This review synthesizes multiple datasets, drawing from cultivation-independent molecular techniques and data from extensive oceanic expeditions, to provide a comprehensive view into the diversity, biogeography, ecophysiology, and activity of marine NCDs. A NCD nifH gene catalog was compiled containing sequences from both PCR-based and PCR-free methods, identifying taxa for future studies. NCD abundances from a novel database of NCD nifH-based abundances were colocalized with environmental data, unveiling distinct distributions and environmental drivers of individual taxa. Mechanisms that NCDs may use to fuel and regulate N2 fixation in response to oxygen and fixed nitrogen availability are discussed, based on a metabolic analysis of recently available Tara Oceans expedition data. The integration of multiple datasets provides a new perspective that enhances understanding of the biology, ecology, and biogeography of marine NCDs and provides tools and directions for future research.

A208 REAL WORLD EVIDENCE ANALYSIS WITH ADALIMUMAB BIOSIMILAR, MSB 11022, REPORTED WITH PATIENT CARE PROGRAM

Background

Injection site reactions (ISR), including injection site pain (ISP) are common adverse events reported with drugs administrated via subcutaneous injections. In clinical trials, the rates of ISR of adalimumab and adalimumab biosimilars range from 3% to 22.8% with citrate-buffer formulations, and from 1.7% to 16.6% with acetate-buffered and other formulations.

Purpose

The objective of this study is to evaluate ISR of adalimumab biosimilar, MSB 11022, in real world setting.

Method

Patients with immune mediated inflammatory diseases (IMIDs) enrolled with patient care program (PSP), and received at least one dose of adalimumab biosimilar, MSB 11022, were followed up. Incidences of injection site reactions, including injection site pain, burning sensation, bruise, erythema, hemorrhage, pruritus, and/or swelling were documented through unsolicited and solicited (outgoing following up calls with patients after their first injection through PSP contacts) reports. The data were collected between April 2021 and July 2022, and the rates of ISRs were assessed.

Result(s)

There were 2812 patients that met criteria through data collection period, with 219 cases of ISR. More than 99% of case reports were through solicited contacts, i.e., through case-manager follow up calls. Overall, rate of injection site reaction is 7.8% in patients with IMIDs treated with adalimumab biosimilar, MSB 11022. The rates of ISRs reported by disease are as follows: 6.8% of patients with Crohn's disease, 8.7% with ulcerative colitis, 8.8% with rheumatoid arthritis, 6.5% with psoriatic arthritis, 7.8% ankylosing spondylitis, 6.1% uveitis, 8.3% with hidradenitis suppurativa, and 11.1% of juvenile rheumatoid arthritis.

Conclusion(s)

Real world data provided evidence that ISR rate of adalimumab biosimilar, MSB 11022, is within the ranges of clinical trial data of adalimumab with citrate-buffer, and other formulations. As far as we know, this is the first real world evidence reported for ISR among adalimumab biosimilars with IMID patients.

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Disclosure of Interest

None Declared

Selective effects of focusing on spatial details in episodic future thinking for self-relevant positive events

Mental simulations of positive future events increase their detail/vividness and plausibility, with effects on cognitive-affective processes such as anticipated and anticipatory pleasure. More recently, spatial details have been distinguished as important in increasing detail and elaborating mental scene construction. Building on this research, this study (N = 54; M age = 26.9) compared simulations of positive, self-relevant future events spatial details (i.e. people, objects, sequences of actions) with simulations focused on content details. Cross-sectionally at baseline, spatial details uniquely predicted phenomenological characteristics of future events, including anticipatory pleasure. The guided simulations increased detail and vividness, mental imagery, and pre-experiencing in both conditions. The content simulation condition did not increase content details relative to the spatial simulation condition, however, the inverse was true. Relatedly, overall detail and vividness were higher in the spatial condition, as was perceived control. The findings are discussed in relation to future thinking and mental health.

O-310 Browsing the Male Genome to Unravel Its Reproductive Potential

Study question

Can whole genome profiling of sperm DNA be used to identify aspects of ART failure and predict embryo developmental competence?

Summary answer

Whole genome profiling of sperm DNA identifies germline gene mutations associated with reproductive failure and helps characterize subtle male factor infertility.

What is known already

A routine semen analysis provides limited information on the characteristics of the male gamete and is unable to predict spermatozoa performance in ART. Therefore, ancillary tests may be used to further assess the male gamete’s reproductive potential. Whole exome sequencing (WES) of the male genome carried out on somatic cells has proven to be a powerful technique capable of identifying the genetic roots of infertility. Here, we aim to preferentially detect germline mutations by exclusively sequencing spermatozoal DNA to identify genes related to the different underlying etiologies of reproductive failure.

Study design, size, duration

Over a 6-year period, 31 consenting couples with negative female infertility workups and normal semen parameters were included in this study. These couples were divided according to whether they reported a successful pregnancy with ART (fertile; n = 10) or not (infertile; n = 21). Sperm aneuploidy assessment by copy number variant (CNV) analysis with WES were carried out on ejaculated spermatozoa. Gene mutation profiles were enlisted and compared between the two patient cohorts to identify genes involved.

Participants/materials, setting, methods

DNA was extracted and amplified from at least 500 spermatozoa (DNA concentration, 760±486 ng/ul; quality, 1.7±0.1 nm) for CNV analyses by WES. Mutations corresponding to the CNV were then annotated and assessed using the CLC Genomic Server 9.0. Genes were considered duplicated or deleted when their read depth was >1.5 or < 0.5 times the median read depth in the control, respectively.

Main results and the role of chance

All couples (n = 31) (maternal age, 37.6±3yrs; paternal age, 39.7±5yrs) had adequate semen parameters (concentration, 59.2±30x106/mL, 44.8±18% motility, normal morphology) and normal peripheral karyotypes.

The fertile cohort (n = 10) underwent 12 ICSI cycles, achieving an 82.6% (57/69) fertilization rate with 10/12 (83.3%) cycles resulting in live births. The infertile cohort (n = 21) underwent 25 ICSI cycles, achieving a 68.4% (91/133) fertilization rate and 6/14 (42.9%) clinical pregnancies, all resulting in pregnancy loss. CNV analysis indicated lower sperm aneuploidy in the fertile (4.0% vs. 8.4%) cohort (P < 0.00001). In both cohorts, mutations associated with sperm–egg fusion (ADAM3A) and acrosomal development (SPACA1, SPATA16) were identified, justifying ICSI utilization.

The infertile cohort included complete fertilization failure, poor early embryo development, implantation failure, or pregnancy loss. Couples with complete fertilization failure (n = 4) had gene deletions (PLCZ1, PIWIL1, ADAM15) indicating sperm-related oocyte-activating deficiency. Those with poor early embryo development (n = 5) had mutations essential for centrosome integrity (HAUS1) and spindle/microtubular stabilization (KIF4A, XRN1). Couples who failed to achieve pregnancy (n = 7) had mutations commonly implicated in embryonic implantation (IL9R) and microtubule/centrosomal integrity (MAP1S). Those with pregnancy losses (n = 5) displayed mutations related to trophoblast development (NLRP7), cell cycle regulation (MARK4, TRIP13, DAB2IP, KIF1C), and a gene linked to recurrent miscarriage (TP53).

Limitations, reasons for caution

Using WES, we were able to identify germline mutations that appear to be involved in various aspects of human reproduction. These findings are new and should be validated in a larger study population. Moreover, although we attempted to control for maternal age, we still cannot exclude confounding female factors.

Wider implications of the findings

Evaluating the sperm genome can help identify elusive genetic factors associated with reproductive competence and help guide treatment options for couples unable to conceive who undergo ART. Therefore, screening spermatozoal DNA may serve as an additional tool in precision medicine to identify and treat subtle male factor infertility.

Trial registration number

N/A

P-107 A Novel Sperm Selection Technique for Embryos of the Desired Sex

Study question

Can a novel sperm selection technique (GST) yield higher rates of embryos and offspring of the desired sex in couples undergoing ICSI with PGT-A?

Summary answer

GST consistently enriched spermatozoa, resulting in a higher proportion of embryos and offspring of the desired sex without impairing clinical outcomes or offspring health.

What is known already

Although various methods to select sex-specific spermatozoa have been proposed over the years, many of these techniques have been shown to have varying degrees of success in addition to being time-consuming and costly. Moreover, the use of fluorescence and electrical charges in some of these methods has raised concerns about their potential contribution to congenital malformations. Here, we tested a novel sperm selection method aimed at achieving a higher proportion of embryos of the desired sex, without compromising clinical outcome or offspring health.

Study design, size, duration

Over a 6-year period, ejaculates from male partners of couples (n = 109) undergoing ICSI with PGT-A were processed using GST to enrich spermatozoa for the couples’ preferred sex. Standard sperm processing was carried out for couples undergoing ICSI exclusively to assess conceptus aneuploidy, comprising the control group (n = 1,261). The proportion of male and female spermatozoa in the initial and selected specimens, PGT-A results, and ICSI outcomes were compared between the two groups.

Participants/materials, setting, methods

A total of 1,370 couples were treated in 2,483 ICSI cycles. Standard sperm processing was performed for 1,261 couples who did not have an offspring sex preference. For 109 consenting couples, GST was used to enrich spermatozoa for their desired sex (IRB 1306014043). To confirm sex enrichment, ≥1,000 sperm cells were screened by fluorescent in-situ hybridization (FISH) for 9 chromosomes. The couples’ PGT-A results and ICSI outcomes were compared between the control and GST cohorts.

Main results and the role of chance

For the control cohort (n = 1,261), ejaculates were processed in the standard fashion. Spermatozoa sex ratio was unaffected. These couples (maternal age, 37.1±4yrs; paternal age, 39.1±6yrs) underwent 2,356 ICSI cycles (1.2±1), yielding an 80.9% fertilization rate (14,830/18,321). PGT-A results confirmed that 46.6% (n = 760) of their embryos were female and 53.4% (n = 872) were male. They achieved a 76.3% (725/950) implantation rate and a 64.9% (617/950) clinical pregnancy rate resulting in 569 healthy deliveries (48% female, 52% male).

From the study cohort (n = 109), 60 couples desired a female and 49 desired a male child. Those who desired female offspring (maternal age, 37.9±4yrs; paternal age, 40.8±6yrs) obtained an 81.6% sperm sex enrichment, per FISH. They underwent 74 ICSI cycles and achieved a 77.6% (592/763) fertilization rate resulting in 78.1% (235/301) female embryos that generated a 79.3% (23/29) implantation rate, yielding 16 singleton deliveries of healthy female offspring that are developing normally.

The 49 couples (maternal age, 37.6±3yrs; paternal age, 40.8±5yrs) preferring male offspring obtained an 80.8% sperm sex enrichment. They underwent 53 ICSI cycles and achieved a 74.7% (481/644) fertilization rate with an equivalent proportion of male embryos (231/292, 79.1%). Their implantation rate was 90.9% (20/22), yielding 14 healthy male singletons, all developing normally.

Limitations, reasons for caution

Although our sperm sex selection method does not guarantee offspring of a specific sex, it allowed couples participating in the study to obtain a greater proportion of conceptuses of their desired genotype. This method does not aim to replace PGT-A, but rather reduce embryo wastage.

Wider implications of the findings

Semen specimens processed by GST yielded satisfactory fertilization and embryo development, comparable to those from the control cohort. Moreover, offspring health was not negatively affected. These encouraging findings indicate that our method is safe and can consistently enrich for the desired embryo sex in a reliable and ethically palatable manner.

Trial registration number

n/a

O-311 Evaluating the Reproductive Potential of Azoospermic Men by Profiling the Genome of Surgically Retrieved Spermatozoa

Study question

Can whole exome sequencing of surgically retrieved spermatozoa from azoospermic men pinpoint mutations related to the etiology of their infertility and ability to support pregnancy?

Summary answer

Identifying key germline mutations involved in spermatogenesis helps explain reproductive failure, regardless of the etiology of the azoospermia.

What is known already

Azoospermia accounts for approximately 15% of male factor infertility cases. Although it can be caused by pre-testicular factors, the most recognized forms are testicular and post-testicular. Post-testicular azoospermia is mainly attributed to a mechanical obstruction, whereas testicular azoospermia, the most challenging form, is characterized by scattered functional germinal epithelia that may fail to support the meiotic process during sperm development. To elucidate the etiology of this condition, genetic studies on somatic cells have been carried out. Here, we perform whole exome sequencing (WES) on surgically retrieved spermatozoa to preferentially detect germline mutations that may be passed on to offspring.

Study design, size, duration

Over 3 years, we recruited patients undergoing epididymal sperm aspiration for acquired obstructive azoospermia (OA; n = 19) or testicular biopsy for nonobstructive azoospermia (NOA; n = 11). Eight men were included as fertile controls. Copy number variants (CNVs) and gene mutation profiles were obtained through WES and compared between the OA and NOA cohorts, followed by sub-analyses within those two categories according to whether they generated a clinical pregnancy (fertile) or not (infertile), while controlling for maternal age.

Participants/materials, setting, methods

Spermatozoal DNA was extracted and amplified from the surgically retrieved specimens (concentration, 742±520 ng/ul; quality, 1.7±0.1 nm). CNVs and gene mutations were detected using CLC Genomic Server 9.0. Genes were considered duplicated or deleted when the read depth was >1.5 or < 0.5 times the median read depth in the control. Common mutations were compared between the OA and NOA cohorts, as well as according to the couples’ clinical outcomes. Female partners had negative infertility workups.

Main results and the role of chance

Of 30 men (paternal age, 42.3±7yrs), 19 OA men underwent epididymal sperm retrievals (concentration, 1.1±4x106/ml, 9±12% motility), while 11 NOA men underwent testicular biopsies (concentration, 0.03±0.4x106/ml, 0.5±1% motility). WES did not indicate a significant difference in sperm aneuploidy between the two etiologies (OA, 1.7%; NOA, 1.8%) compared to the control (1.1%).

In OA patients, only 3 housekeeping-related genes were deleted, while in the NOA cohort, 5 genes involved in RNA transcription (POLR2L), apoptosis (AP5M1), and basic spermiogenic functions (AP1S2, AP1G2, APOE) were deleted.

OA patients and their partners (maternal age, 36.8±4yrs) underwent 19 ICSI cycles resulting in a delivery rate of 47.4% (9/19). Those able to reproduce (n = 9) shared a mutation in ZNF749, specifically affecting sperm production. The infertile men (n = 10) all shared a PRB1 deletion, controlling essential DNA replication.

NOA men and their partners (maternal age, 38.2±2yrs) underwent 11 ICSI cycles, yielding a delivery rate of 72.7% (8/11). The fertile men (n = 8) all shared a MPIG6B deletion, involved in stem cell lineage differentiation. All of their infertile counterparts (n = 3) presented gene deletions not only involved in spermato/spermio-genesis (n = 4) but, most importantly, also superimposed with those encoding early embryonic development (MBD5, CCAR1, PMEPA1, POLK, REC8, REPIN1, MAPRE3, ARL4C).  

Limitations, reasons for caution

Although maternal age was controlled for, confounding factors related to the female partner cannot entirely be excluded. While men unable to reproduce shared common gene mutations providing information about their condition, these findings still need to be confirmed in larger observations.

Wider implications of the findings

By performing WES, we were able to identify specific mutations associated with compromised embryo developmental competence of surgically retrieved spermatozoa. DNA sequencing technologies help identify gametes capable of sustaining a pregnancy even in the most severe form of male infertility, laying the groundwork for precision medicine in this field.

Trial registration number

N/A

O-044 ICSI in the lab: from vintage to AI

With the advent of in vitro fertilization (IVF) by Patrick Steptoe and Bob Edwards in the late 70s, the first conception outside of the human body resulted in the birth of Louise Brown. Although a terrific success, limitations of IVF surfaced, represented by the unexpected complete fertilization failure with suboptimal or dysfunctional spermatozoa.

This prompted curiosity toward individual spermatozoa for a deeper understanding of its role aimed at enhancing the interaction between complementary gametes. Techniques were designed to manipulate the oocytes, such as stripping, partially digesting, or cracking the zona pellucida (ZP). These methods were palliative solutions to overcome fertilization failure and were often plagued by polyspermy. As a result, more direct approaches were implemented to overcome the ZP, such as subzonal injection (SUZI) that although more consistent, was still unable to overcome the shortcomings of dysfunctional spermatozoa. This laid the foundation for the utilization of ICSI that, whilst attempted by some investigators, became popular when Gianpiero Palermo serendipitously inserted one spermatozoon into the ooplasm during SUZI. Consistent fertilization then followed by injecting a cohort of oocytes by ICSI in SUZI cycles, and replacement of these embryos led to 4 pregnancies described in the first clinical ICSI report. To minimize oocyte damage, the procedure was further refined by inducing a deep invagination of the oolemma toward the 9 o’clock position, granting higher chances of post-injection survival.

What set apart ICSI from other forms of ART was that any sperm sample, regardless of quality/quantity, would yield fertilization. Indeed, ICSI is the sole insemination method used with epididymal and testicular spermatozoa and has therefore revolutionized fertility treatment of azoospermic men. Indeed, even immotile testicular spermatozoa can still fertilize and yield successful pregnancies, albeit at a lower rate than their motile counterpart. Also, for these semen sources, aggressive sperm immobilization was introduced to enhance sperm membrane permeabilization and grant optimal fertilization results.

Furthermore, ICSI has transformed the field of reproductive medicine by assisting other reproductive techniques, such as testing embryos for single gene defects to reduce the occurence of sperm DNA contamination, or overcoming the cryostress-induced changes of the ZP during cryopreservation allowing the oocyte to be fertilized at a higher rate. Oocyte cryopreservation now empowers women in their reproductive age to ordain their childbearing future.

ICSI has proven to be the ultimate technique to overcome male infertility and has broadened its indication by yielding consistent fertilization and successful pregnancies in most circumstances, ensuring that men have the chance of fathering their own progeny.

To date, ICSI is applied in several countries, and in some, is performed as the preferred/sole insemination method contributing to the birth of millions of babies worldwide. Thus far, no concerning differences have been seen in the health of ICSI versus standard IVF offspring, or even naturally conceived. In fact, it has been currently established that young adults of both genders born through ICSI retain their reproductive health.

Despite its growing popularity, ICSI does not always succeed but still provides an invaluable platform to deepen our knowledge of gamete biology and helps to investigate/overcome some of the most severe and persistent forms of infertility. For example, combined with assisted gamete treatment, ICSI allows couples plagued by sperm-bound oocyte-activation-deficiency to achieve pregnancy.

The need to increase access and curtail costs of reproductive care has led to the testing of automation in ART. This is also occurring with ICSI and to date, different automated modules have been proposed for oocyte denudation, sperm tracking, and robotic ICSI. Concurrently, there has been an interest in experimenting with artificial intelligence in the IVF laboratory to minimize human shortcomings and ensure that the best spermatozoon is chosen.

O-314 Epigenetic Profiling of Seminal Plasma in NOA Men to Predict Successful Testicular Sperm Retrieval

Study question

Can epigenetic profiling of seminal plasma be used to predict successful testicular sperm retrieval for men with non-obstructive azoospermia (NOA)?

Summary answer

Epigenetic screening of cell-free seminal RNA identified gene imbalances in NOA men, with specific correlation to those who failed to yield spermatozoa at testicular biopsy.

What is known already

Although the chance of a successful microdissection testicular sperm extraction (micro-TESE) in men with NOA can be up to 60%, the procedure may still fail to yield spermatozoa. Several factors have been proposed to predict a successful retrieval, including FSH, inhibin B, genetics, and histopathology. Although histopathology would be the most reliable of these to predict successful micro-TESE, it is equally invasive to perform. Indeed, cell-free RNA extracted from testicular biopsy specimens has been shown to be differentially expressed in infertile men according to the origin of their azoospermia, whether obstructive or nonobstructive, and in relation to a normozoospermic control.

Study design, size, duration

Over a 2-year period, we identified men in whom no spermatozoa were identified despite extensive semen analyses conducted by multiple embryologists. These patients, who were negative for Y microdeletion, subsequently underwent micro-TESE. For consenting men, we performed epigenetic analyses on their seminal plasma by RNAseq. Significant differentially expressed gene (DEG) profiles were then assessed and compared according to whether surgical sperm retrieval successfully yielded spermatozoa (+TESE) or not (-TESE).

Participants/materials, setting, methods

RNA was isolated from the ejaculates for RNAseq using a commercially available spin column kit. RNA isolates were sequenced by Illumina HiSeq at 2x150bp. An absolute log2fold change of > 1 and a P-value of < 0.05 was considered significant. DEG profiles were compared within, as well as between, the +TESE and -TESE cohorts in comparison to a donor control.

Main results and the role of chance

All 12 men (37.3±6yrs) had normal peripheral karyotypes. Six (38.0±7yrs) underwent successful testicular sperm retrievals, defining the +TESE cohort. These men exclusively shared 10 significantly imbalanced genes involved in processes such as spermatogenesis (n = 4), sperm function (n = 2), and testis development (n = 1).

For the 6 men (36.6±5 yrs) who underwent testicular sperm retrievals that failed to yield spermatozoa (-TESE), we identified 16 significantly imbalanced genes, exclusively shared by these patients. These genes are mainly involved in spermatogenesis (n = 9), sperm maturation (n = 1), and cell cycle regulation (n = 4).

We then compared the DEG profiles between the +TESE and -TESE cohorts and identified 8 imbalanced genes that were shared among all 12 NOA men.

Of interest, TPTE2 was partially (67%) expressed in patients from the +TESE group, while IGSF11-AS1 was underexpressed in all men from the -TESE group. Both of these genes are implicated in spermatogenic defects and are normally highly expressed in the testis.

Interestingly, we identified a gene (NA) that was solely and specifically underexpressed in all men from the -TESE group, yet simultaneously overexpressed in all men from the +TESE group. NA, which is well known for its role in sialic acid metabolism, is also present on the sperm acrosome.

Limitations, reasons for caution

Using non-invasive RNAseq on the seminal plasma of NOA men, we were able to identify DEGs according to whether spermatozoa were successfully retrieved or had failed retrieval with micro-TESE. Although intriguing, these are preliminary results that should be further validated in a larger study cohort.

Wider implications of the findings

RNAseq identified genes shared within the same prognostic cohort. Moreover, differential expression of some specific genes predicted micro-TESE outcome. This epigenetic assessment, carried out on the ejaculate, can therefore be used as a non-invasive biomarker tool to predict loss of spermatogenesis in NOA men, sparing them from unnecessary surgery.

Trial registration number

N/A

P-270 Assisted gamete treatment to pinpoint acquired meiotic maturity and overcome oocyte activation deficiency contributed by both gametes

Study question

How can we treat couples with complete and persistent fertilization failure with ICSI linked to a combination of oocyte- and sperm-related oocyte activation deficiency (OAD)?

Summary answer

By targeting spindle presence, we optimized oocyte response to chemical activation and enhanced fertilization. Genomic assessment confirmed gamete contribution.

What is known already

Total fertilization failure occurs in 1-3% of all intracytoplasmic sperm injection (ICSI) cases. In sperm-factor OAD, the lack of phospholipase C zeta (PLCζ) prevents the spermatozoon from initiating downstream calcium oscillation in the oocyte. In these cases, assisted gamete treatment (AGT), which exposes gametes to calcium ionophore, has been adopted to artificially trigger the influx of calcium ions and has been shown to effectively improve fertilization. However, AGT is limited to triggering an intracytoplasmic calcium influx and still requires optimal ooplasmic maturity.

Study design, size, duration

Over the past 17 months, we identified couples with compromised PLCζ and reported persistent fertilization failure with ICSI despite AGT treatment. We then devised a treatment plan comprising an extended in vitro culture (IVC) to pinpoint meiotic oocyte maturity confirmed by the presence of a meiotic II spindle and followed by AGT post-ICSI. Genomic assessment was also carried out.

Participants/materials, setting, methods

Two couples with recurrent and total fertilization failure even after AGT were included. PLCζ expression was assessed using immunofluorescence on ≥ 200 cells/specimen with a 30% threshold. In the follow-up cycles, IVC was extended for at least 8 hours between retrieval and ICSI. Metaphase II spindles were visualized by Oosight®. AGT was performed by exposing both spermatozoa and oocytes to calcium ionophore. NGS was performed on spermatozoa to identify gene mutations involved in fertilization.

Main results and the role of chance

We identified 2 couples (couple A: 37-year-old female, 39-year-old male; couple B: 32-year-old female, 33-year-old male) with the following semen parameters: average volume of 2.6 ml, concentration of 82.0x106/ml, 44% motility, and normal morphology of 3%. The oocyte maturation rate was 76.3% (45/59) but resulted in zero fertilized out of a total of 45 MII oocytes injected. In-house PLCζ assessment revealed a deficiency of oocyte activation factor at 12.9%. AGT treatment alone failed to enhance fertilization on a subsequent cycle, resulting in 0% (0/8) and 5.6% (1/18) fertilization rates for couples A and B, respectively. Couple A then underwent 3 ICSI cycles with extended IVC and AGT; upon examination of nuclear maturity, 91.4% (32/35) of oocytes displayed normal metaphase II spindle and achieved an overall fertilization rate of 43.8% (14/32). To date, 12 blastocysts were cryopreserved. In couple B, 27 oocytes out of 34 retrieved presented normal metaphase II spindles after extended IVC; ICSI with AGT yielded a fertilization rate of 63.0% (17/27). All 17 zygotes were cryopreserved. Overall, our treatment improved fertilization to an overall rate of 52.5% (31/59, P  <0.00001). Genomic assessment of spermatozoa identified gene mutations involved in fertilization (ADAM15, ADAM30) and calcium channel activity (CATSPER1).

Limitations, reasons for caution

Assisted gamete treatment can enhance fertilization in cases of deficiency in PLCζ. However, chemical activation requires a responsive ooplasm that has reached meiotic maturity. These rare cases require precise diagnoses and tailored treatment techniques to address each aspect of sperm- and/or oocyte-factor OAD.

Wider implications of the findings

Our study has demonstrated the usefulness of extended IVC by targeting spindle presence to enhance chemical responses to AGT. Our findings show that although calcium ionophore can trigger the release of intracellular calcium and allow fertilization, a fully mature ooplasm is required.

Trial registration number

N/A

Highly Diverse Synechococcus Pigment Types in the Eastern Indian Ocean

Marine picocyanobacteria Synechococcus exhibit highly diverse pigment types (PTs) and hence possess great advantage to utilize different spectrum of light effectively and to occupy a wide range of light niches. In this study, we explored the diversity of Synechococcus PTs in the eastern Indian Ocean (EIO), surface water of Strait of Malacca (SSM), and coastal waters of Sri Lanka (SSL). All the detected PTs were phycourobilin (PUB) containing PT 3 and showed distinct distribution patterns. Low PUB PT 3a and partial chromatic acclimater PT 3eA dominated in coastal and shallow waters (SSM and SSL). In contrast, high PUB and chromatic acclimaters PT 3dA and PT 3c/3dB were mainly distributed in open ocean (EIO). PT 3dA and PT 3c/3dB occurred at similar depths of the lower euphotic layers but showed distinct distribution pattern that are partially exclusive, indicating that they compete with each other for the same light niche. Interestingly, the newly described PT 3f was detected with high relative abundances at all stations and particularly dominated in the upper euphotic layer in EIO, which was confirmed with PT-specific quantitative polymerase chain reaction (qPCR). The relative abundance of PT 3f was negatively correlated with nutrient level, implying that PT 3f is adapted to oligotrophic waters. Pronounced niche partition of different PTs was observed in the upper and lower layers of euphotic zone in EIO and SSM/SSL. Light, nutrients, and strong stratification may play important roles in the niche partition of different PTs. Further analysis about ecologically significant taxonomic units revealed high diversity within each PT at different locations, which provided insights for understanding specific PT with wide range of niches.

O-119 Evaluating the reproductive potential of azoospermic men by germline mutation profiling

Study question

Can whole exome sequencing (WES) of spermatozoa from azoospermic men identify mutations related to the etiology of their infertility and ability to support a pregnancy?

Summary answer

Key de novo germline mutations that affect sperm production and/or embryo developmental competence may explain reproductive failure in azoospermic men, regardless of the etiology.

What is known already

Azoospermia accounts for approximately 15% of male factor infertility cases. Although it can be caused by pre-testicular factors, the most recognized forms are testicular and post-testicular. While post-testicular azoospermia is mainly due to a mechanical obstruction, testicular azoospermia, the most severe form, is characterized by scattered functional germinal epithelia that strive to support the meiotic process during gamete development. To shed light on the etiology of this condition, genetic studies have been performed, albeit exclusively on peripheral blood. We chose to perform a genomic assessment of spermatozoa to preferentially detect germline mutations that may be passed to the progeny.

Study design, size, duration

In a 2-year period, we recruited infertile men undergoing epididymal aspiration for acquired obstructive azoospermia (OA; n = 19) or testicular retrieval for nonobstructive azoospermia (NOA; n = 10). Four additional men were included as fertile controls. Following WES, copy number variants (CNVs) and gene mutation profiles were compared between the OA and NOA patients, and within those two categories, in relation to whether they generated a clinical pregnancy (fertile) or not (infertile).

Participants/materials, setting, methods

Spermatozoal DNA was extracted and amplified from the surgically retrieved specimens of consenting men (DNA concentration, 762±492 ng/ul; quality, 1.7±0.1 nm). CNVs, gene mutations, duplications, and deletions were detected using the CLC Genomic Server 9.0. Genes were considered duplicated or deleted when the read depth was >1.5 or < 0.5 times the median read depth in the control. Common mutations in the OA and NOA cohorts were assessed according to the couples’ clinical outcome.

Main results and the role of chance

Of 29 couples (maternal age, 41.9±7yrs; paternal age, 42.5±7yrs), 19 OA men underwent epididymal sperm retrieval (1.1±4x106/ml concentration, 9±12% motility) while 10 NOA men underwent testicular biopsy (0.03±0.2x106/ml concentration, 0.5±1% motility). WES did not reveal a significant difference in sperm aneuploidy between the two etiologies (OA, 1.8%; NOA, 1.9%).

In OA patients, only 3 genes were deleted, mainly housekeeping-related, while in the NOA cohort, 5 genes were deleted, involved in RNA transcription (POLR2L) and apoptosis (AP5M1), in addition to spermiogenic functions (AP1S2, AP1G2, APOE).

OA patients and their partners (maternal age, 36.8±4yrs) underwent 19 ICSI cycles that resulted in a pregnancy and delivery rate of 47.4% (9/19). Those able to reproduce (n = 9) shared a mutation in ZNF749, a gene affecting only sperm production. The infertile individuals (n = 10) all had a deletion on PRB1, controlling essential DNA replication.

NOA men and their partners (maternal age, 38.2±2yrs) underwent 10 ICSI cycles, yielding a clinical pregnancy rate of 70% (7/10). The fertile men (n = 7) had a concurrent gene deletion involved in stem cell lineage differentiation (MPIG6B). Their infertile counterparts (n = 3) had deleted genes involved in spermato/spermio-genesis (n = 6) and, most importantly, in early embryonic development (MBD5, CCAR1, PMEPA1, POLK, REC9, REPIN1, MAPRE3, and ARL4C).

Limitations, reasons for caution

This is a novel study with limited observations. The presence of housekeeping-related mutations in fertile OA men as well as the DNA replication mutation in infertile OA patients, considering the acquired condition, remains puzzling. Although maternal age was controlled for, confounding factors related to the female partner cannot be excluded.

Wider implications of the findings

Screening men for germline mutations provides valuable information on their ability to reproduce, regardless of the etiology of azoospermia. Genome profiling was able to identify reasons for failed reproductive performance in azoospermic men, particularly those individuals with secretory azoospermia (NOA). Genomic profiling may identify gametes with retained embryo developmental competence.

Trial registration number

n/a

O-094 Utilization of ultrastructural analysis and genomics of spermatozoa to better characterize subtle forms of male factor infertility

Study question

Can sequencing the sperm genome provide insight into the various forms of male factor infertility caused by sperm organelle ultrastructural defects?

Summary answer

A comprehensive genomic assessment of spermatozoal DNA is able to identify genetic causes of ultrastructural defects visualized by transmission electron microscopy (TEM).

What is known already

To evaluate a man’s reproductive potential, a conventional semen analysis through the assessment of concentration, motility, and morphology can indicate the proficiency of male gametes. Among those, conventional morphology assay can only provide indirect information on the different components of the sperm cell. The assessment of nanoscopic details such as chromatin, centriolar, mitochondrial, and axonemal components can only be observed by TEM. Indeed, TEM has been used to identify defects in the acrosome, chromatin compaction, and axonemal/periaxonemal structures. Furthermore, exome sequencing of spermatozoal DNA may identify novel causes and candidate genes for these ultrastructural defects.

Study design, size, duration

In the past 2 years, 20 men with history of fertilization failure or severe astheno-/terato-zoospermia were selected for TEM analysis of their spermatozoa, while 3 fertile men served as controls. Sperm head characteristics, intactness of fibrous sheath, and axonemal/periaxonemal structure were examined by diagnostic TEM. For consenting patients, NGS assessment was concurrently performed to identify mutations responsible for the structural abnormalities identified by TEM.

Participants/materials, setting, methods

TEM was performed on the ejaculates of 20 infertile patients and 3 fertile controls. Post-centrifugation cell pellets were resuspended, fixed, and dehydrated to be infiltrated and embedded onto the resin. Fixed specimens were sliced by ultramicrotome to 100-nm sections, then viewed by JEOL-1400 electron microscope at 300,000X magnification. At least 100 spermatozoa were evaluated by TEM. For consenting patients, DNA was extracted and amplified from at least 500 spermatozoa for concurrent NGS analysis.

Main results and the role of chance

Four types of sperm ultrastructural defects were observed, including globozoospermia, dysplasia of fibrous sheath (DFS), proximal centriole defect, and primary ciliary dyskinesia (PCD). One combined case of globozoospermia and DFS was identified. In globozoospermic patients (n = 13), 97-100% of the spermatozoa displayed characteristic spherical heads with absence of acrosomes, dispersed chromatin, and perinuclear theca deformities. Centrosomal and axonemal structures were conserved. NGS identified gene deletions (DPY19L, PICK1, SPATA16) directly related to the globozoospermic phenotype. In patients with DFS (n = 4), complete absence of flagellum was observed in 90-100% of spermatozoa. These defective gametes also displayed mitochondria disorganization, microtubular deformities, and cytoplasmic residues containing coiled flagellum with deformed capitulum within the plasma membrane. Contrary to the globozoospermia, acrosomes and nuclei appeared normal, indicating incomplete late spermiogenesis. Indeed, NGS confirmed gene deletions involved in flagellar development/function (AKAP4, SPAG16, CATSPER1). For the patient with proximal centriole defect (n = 1), sperm nucleus, fibrous sheath, and flagellar structure were conserved. However, 90% of proximal centrioles assessed exhibited microtubular disorganization, confirmed by ODF2 mutation per NGS. In the PCD patient (n = 1), chaotic flagellar microtubule arrangement and absence of outer dynein arms were prevalent in 90% of axonemal cross-sections examined, which was explained by a DNAH5 gene deletion.

Limitations, reasons for caution

While TEM can overcome the limitations of conventional semen analysis by providing direct visualization of the inner organelle arrangement of spermatozoa to accurately diagnose rare sperm pathologies, it is not routinely applied in clinics due to its high cost and technical specifications. Therefore, confirmatory NGS can provide additional diagnostic value.

Wider implications of the findings

Ultrastructural analysis with a concurrent genomic assessment characterized phenotypes and genotypes of rare sperm pathologies in infertile men. The utilization of TEM, corroborated by genomic assay, is therefore crucial for clinical and translational reproductive medicine to better characterize male factor infertility.

Trial registration number

N/A

Distinct interaction effects of warming and anthropogenic input on diatoms and dinoflagellates in an urbanized estuarine ecosystem

Diatoms and dinoflagellates are two major bloom-forming phytoplankton groups in coastal ecosystems and their dominances will notably affect the marine ecosystems. By analyzing an 18-year monthly monitoring dataset (2000-2017) in the Pearl River Estuary (one of the most highly urbanized and populated estuarine in the world), we observe an increasing trend of the diatom to dinoflagellate ratio (Diatom/Dino). As revealed by multiple statistical models (generalized additive mixed model, random forest, and gradient boosting algorithms), both groups are positively correlated with temperature. Diatoms are positively correlated with nitrate and negatively correlated with ammonium while dinoflagellates show an opposite pattern. The Diatom/Dino trend is explained by an altered nutrient composition caused by a decadal increase in anthropogenic input, at which nitrate increased rapidly while ammonium and phosphate were relatively constant. Regarding the interaction of warming and nutrient dynamics, we observe an additive effect of warming and nitrate enrichment that promotes the increase in diatom cell density, while the dinoflagellate cell density only increases with warming when nutrients are depleted. Our models predict that the Diatom/Dino ratio will further increase with increasing anthropogenic input and global warming in subtropical estuarine ecosystems with nitrate as the dominant inorganic nitrogen; its ecological consequences are worthy of further investigation.

Gamma4: a genetically versatile Gammaproteobacterial nifH phylotype that is widely distributed in the North Pacific Ocean

Despite the increasing reports of non-cyanobacterial diazotrophs (NCDs) in pelagic waters, only one NCD (GammaA) has been relatively well described, whose genome and physiology are still unclear. Here we present a comprehensive analysis of the biogeography and ecophysiology of a widely distributed NCD, Gamma4. Gamma4 was the most abundant Gammaproteobacterial NCD along transects across the subtropical North Pacific. Using quantitative PCR, Gamma4 was detectable throughout the surface waters of North Pacific (7°N-55°N, 138°E-80°W), whereas GammaA was detected at <2/3 of the stations. Gamma4 was abundant during autumn-winter and positively correlated with chlorophyll a, while GammaA thrived during spring-summer and was positively correlated with temperature. Environmental clones affiliated with Gamma4 were widely detected in pelagic waters, oxygen minimum zones and even dinoflagellate microbiomes. By analysing the metabolic potential of a genome of Gamma4 reconstructed from the Tara Oceans dataset, we suggest that Gamma4 is a versatile heterotrophic NCD equipped with multiple strategies in scavenging phosphate (and iron) and for respiratory protection of nitrogenase. The transcription of nitrogenase genes is putatively regulated by Fnr-NifL-NifA and GlnD-GlnK systems that respond to intracellular oxygen and glutamate concentration. These results provide important implications for the potential life strategies of pelagic NCDs.

Population dynamics and interactions of Noctiluca scintillans and Mesodinium rubrum during their successive blooms in a subtropical coastal water

A time series field survey were conducted in Port Shelter, a subtropical coastal water in NW Pacific, beginning before the onset of a chain of Noctiluca scintillans and/or Mesodinium rubrum blooms, and ending after the blooms had declined. At the first mixed bloom stage, seed of N. scintillans and the consequent outbreak of both N. scintillans and M. rubrum were largely due to the physical forcing. Plenty food supply and their different feeding habits supported N. scintillans and M. rubrum to bloom massively and concomitantly. Following that, there was a small N. scintillans bloom followed by a small crest of M. rubrum. Their initiation and scale were mainly affected by limited food supply and/or the inferior food source. Sudden change of wind from mild northeast wind to strong southeast wind might contribute to the termination of N. scintillans bloom. Finally, physical accumulation was the most important driving factors of the formation and dispersal of the third and largest bloom of N. scintillans. Formation of these bloom events may involve vertical migration and/or the concentrating mechanism of M. rubrum and N. scintillans. Meanwhile, biotic interactions such as mutual supportive relationship between N. scintillans and M. rubrum, and O. hongkongense fed on the progametes of N. scintillans, as well as other abiotic factors like seawater temperature and rainfall, also play important roles in this series of bloom events. Our findings have important implications for coastal zones worldwide, which are affected recurrently by these two ubiquitous red tide-forming species.

Residual lymph node tumour burden following removal of a single axillary sentinel lymph with macrometastatic disease in women with screen-detected invasive breast cancer

Background

Women with screen-detected invasive breast cancer who have macrometastatic disease on axillary sentinel lymph node biopsy (SLNB) are usually offered either surgical axillary node clearance (ANC) or axillary radiotherapy. These treatments can lead to significant complications for patients. The aim of this study was to identify a group of patients who may not require completion ANC.

Methods

Data from the NHS Breast Screening Programme between 1 April 2012 and 31 March 2017 were interrogated to identify women with invasive breast carcinoma and a single sentinel lymph node (SLN) with macrometastatic disease who subsequently proceeded to completion ANC. Univariable and multivariable analyses were performed to identify patients with a single positive SLN who had no further lymph node metastasis on ANC.

Results

Of the 2401 women included in the cohort, the presence of non-sentinel node disease was significantly affected by: the number of nodes obtained at SLNB (odds ratio (OR) 0.49 for retrieval of more than 1 node), invasive size of tumour (OR 1.63 for size greater than 20 mm), surgical treatment (OR 1.34 for mastectomy), human epidermal growth factor receptor (HER) 2 status (OR 0.71 for HER2 positivity), and patient age (OR 1.10 for age less than 50 years; OR 1.46 for age greater than 70 years). Patients aged less than 70 years, with tumour size smaller than 2 cm, more than one node retrieved on SLNB, and who had breast-conserving surgery had a lower chance of positive non-sentinel nodes on completion ANC compared with other patients.

Conclusion

This study, of a purely screen-detected breast cancer cohort, identified a subset of patients who may be spared completion ANC in the event of a single axillary SLN with macrometastasis.

Rare bacteria in seawater are dominant in the bacterial assemblage associated with the Bloom-forming dinoflagellate Noctiluca scintillans

Noctiluca scintillans is a bloom-forming dinoflagellate, which is widely distributed in the global coastal seas. Associated bacteria have been proven to be essential for the survival and growth of zooplanktons. However, the diversity and function of bacteria associated with Noctiluca scintillans are under studied and largely unknown. Here, we examined the diversity and function of bacteria associated with field-acquired and laboratory-maintained Noctiluca cells. Our results showed that the bacterial communities associated with the laboratory-maintained Noctiluca were dominated by Rhodobacterales, whereas those associated with the field-acquired Noctiluca varied over time. In addition, major Noctiluca-associated bacteria had low relative abundance in the ambient environment. We also observed that when field-acquired Noctiluca were cultivated with a mono-species food source, there was a shift in the associated bacterial communities. Metagenomic analysis showed that genes involved in DNA replication/repair and osmotic regulation were more abundant than other genes in the Noctiluca-associated bacterial community. Furthermore, the associated bacteria were able to degrade various complex carbohydrates and actively participate in the nitrogen cycle in their host cells. In addition, a draft genome of the Rickettsiaceae strain was recovered, and we showed that the genome did not contain genes encoding hexokinase and phosphoglucomutase, two key enzymes involved in glucose utilization. Instead, the primary energy sources of this bacteria were shown to be glutamate, glutamine and pyruvate, which might be obtained from the host. We suggest that in return, the Rickettsiaceae strain is likely to provide cofactors and amino acids to the host. This study highlights the spatial and temporal complexity of bacterial communities associated with Noctiluca, and provides valuable insights into the interaction between a host and its associated bacteria.

Differential Distribution and Determinants of Ammonia Oxidizing Archaea Sublineages in the Oxygen Minimum Zone off Costa Rica

Ammonia oxidizing archaea (AOA) are microbes that are widely distributed in the ocean that convert ammonia to nitrite for energy acquisition in the presence of oxygen. Recent study has unraveled highly diverse sublineages within the previously defined AOA ecotypes (i.e., water column A (WCA) and water column B (WCB)), although the eco-physiology and environmental determinants of WCB subclades remain largely unclear. In this study, we examined the AOA communities along the water columns (40-3000 m depth) in the Costa Rica Dome (CRD) upwelling region in the eastern tropical North Pacific Ocean. Highly diverse AOA communities that were significantly different from those in oxygenated water layers were observed in the core layer of the oxygen minimum zone (OMZ), where the dissolved oxygen (DO) concentration was < 2μM. Moreover, a number of AOA phylotypes were found to be enriched in the OMZ core. Most of them were negatively correlated with DO and were also detected in other OMZs in the Arabian Sea and Gulf of California, which suggests low oxygen adaptation. This study provided the first insight into the differential niche partitioning and environmental determinants of various subclades within the ecotype WCB. Our results indicated that the ecotype WCB did indeed consist of various sublineages with different eco-physiologies, which should be further explored.

Metatranscriptomics of the bacterial community in response to atmospheric deposition in the Western North Pacific Ocean

Atmospheric deposition represents a major vector of both macro- and micro-nutrients to the oligotrophic open oceans, potentially imposing a profound impact on the functioning of the microbial community. Whereas bacterial responses to atmospheric deposition are being studied at the community level, corresponding functional changes are essentially unknown. Here we conducted a microcosm experiment coupled with metatranscriptomic analyses to elucidate taxonomic and functional profiles of the bacterial community in response to East Asian aerosols in the Western North Pacific Ocean (WNPO). While the abundance of heterotrophic bacteria showed a minor change, cyanobacterial cell count number decreased dramatically, with Prochlorococcus and Synechococcus counts reduced by 83.2% and 21.5% in the aerosol treatment in relation to the control. Expression of transcripts related with Prochlorococcus, Synechococcus, Trichodesmium and Crocosphaera both were lower in the treatment (5.7%, 2.3%, 0.5% and 0.02%, respectively) than in the control (18.6%, 2.7%, 9.8% and 0.14%, respectively). Aerosol addition led to an increase in transcripts involved in iron metabolism (tonB, feoB, irr, exbB), indicating Fe limitation. Heavy metal toxicity was evidenced by an elevated expression of resistance genes, such as czcC, czcB, czcA and a probable Co/Zn/Cd efflux protein, and a range of genes functioning against oxidative stress. Our findings provide insights into an inhibitory effect of high-flux East Asian aerosols on cyanobacteria in the WNPO likely due to Fe scavenging and heavy metal toxicity.

A new method for the high-precision assessment of tumor changes in response to treatment

Motivation

Imaging demonstrates that preclinical and human tumors are heterogeneous, i.e. a single tumor can exhibit multiple regions that behave differently during both development and also in response to treatment. The large variations observed in control group, tumors can obscure detection of significant therapeutic effects due to the ambiguity in attributing causes of change. This can hinder development of effective therapies due to limitations in experimental design rather than due to therapeutic failure. An improved method to model biological variation and heterogeneity in imaging signals is described. Specifically, linear Poisson modeling (LPM) evaluates changes in apparent diffusion co-efficient between baseline and 72 h after radiotherapy, in two xenograft models of colorectal cancer. The statistical significance of measured changes is compared to those attainable using a conventional t-test analysis on basic apparent diffusion co-efficient distribution parameters.

Results

When LPMs were applied to treated tumors, the LPMs detected highly significant changes. The analyses were significant for all tumors, equating to a gain in power of 4-fold (i.e. equivalent to having a sample size 16 times larger), compared with the conventional approach. In contrast, highly significant changes are only detected at a cohort level using t-tests, restricting their potential use within personalized medicine and increasing the number of animals required during testing. Furthermore, LPM enabled the relative volumes of responding and non-responding tissue to be estimated for each xenograft model. Leave-one-out analysis of the treated xenografts provided quality control and identified potential outliers, raising confidence in LPM data at clinically relevant sample sizes.

Availability and implementation

TINA Vision open source software is available from www.tina-vision.net.

Supplementary information

Supplementary data are available at Bioinformatics online.

A treatment algorithm for couples with unexplained infertility based on sperm chromatin assessment

OBJECTIVE

To design a reproductive treatment algorithm based on the sperm DNA fragmentation (SDF) for couples with unexplained infertility following a poor intrauterine insemination (IUI) outcome.

DESIGN

Couples that failed IUI with no apparent reproductive issue in both partners were allocated to diverse reproductive treatments on the basis of SDF.

SETTING

Reproductive medical center in an academic setting.

PATIENT(S)

Over 4 years, couples with an unexpected poor IUI outcome and no apparent female or male partner reproductive issues were recruited.

INTERVENTION(S)

IUI, IVF, and ICSI were performed in the standard fashion following sperm SDF assays.

MAIN OUTCOMES MEASURE(S)

Fertilization rate, implantation rate, pregnancy characteristics, and delivery rates.

RESULT(S)

A total of 354 couples with unexplained infertility and normal semen parameters underwent 1133 IUI cycles. Clinical pregnancy rate (CPR) with IUI at our center in an age-matched cohort is 23.9% while the study cohort had 1.8%. Following SDF assessment, couples with failed IUI attempts but normal SDF (SCSA 9.8 ± 4.6%; TUNEL 11.8 ± 6.2%) underwent IVF with a CPR of 12.7%; those with abnormal SDF underwent ICSI with ejaculated spermatozoa, resulting in a CPR of 18.7%. This group included couples with normal SDF that had failed IVF. Couples with abnormal SDF that failed ICSI with ejaculated spermatozoa achieved a CPR of 31.0% with surgically retrieved spermatozoa.

CONCLUSION(S)

Couples with unexplained infertility that present with unexpectedly poor IUI outcomes can be funneled into a treatment algorithm guided by the integrity of the sperm genome for higher chances of pregnancy using an alternate method of insemination.

Metagenomic Insights Into the Microbial Community and Nutrient Cycling in the Western Subarctic Pacific Ocean

The composition and metabolic functions of prokaryotic communities in the western subarctic Pacific (WSP), where strong mixing of waters from the Sea of Okhotsk and the East Kamchatka Current result in transfer to the Oyashio Current, were investigated using a shotgun metagenome sequencing approach. Functional metabolic genes related to nutrient cycling of nitrogen, sulfur, carbohydrates, iron and amino acids were differently distributed between the surface and deep waters of the WSP. Genes related to nitrogen metabolism were mainly found in deep waters, where Thaumarchaeaota, Sphingomonadales, and Pseudomonadales were closely associated and performing important roles in ammonia oxidation, assimilatory nitrate reduction, and dissimilatory nitrate reduction processes, respectively. In addition, orders affiliated to Spingobacteria and Alphaproteobacteria were crucial for sulfate reduction and abundant at 3000 m, whereas orders affiliated to Gammaproteobacteria, which harbored the most sulfate reduction genes, were abundant at 1000 m. Additionally, when compared with the East Kamchatka Current, the prokaryotes in the Oyashio Current were likely to consume more energy for synthesizing cellular components. Also, genes encoding iron transport and siderophore biosynthesis proteins were in low abundance, indicating that the iron was not a limiting factor in the Oyashio current. In contrast, in the East Kamchatka Current, prokaryotes were more likely to directly utilize the amino acids and absorb iron from the environment. Overall, our data indicated that the transformation from the East Kamchatka Current to the Oyashio Current reshapes not only the composition of microbial community, but also the function of the metabolic processes. These results extended our knowledge of the microbial composition and potential metabolism in the WSP.

Abstract P4-15-02: Impact of radiotherapy and endocrine therapy on further events: Final multivariate analysis of a prospective, national cohort study of screen detected ductal carcinoma in situ (DCIS) of the breast

Key words: DCIS, radiotherapy, endocrine therapy, survival, surgical margins

Background:

The benefits and risks of breast screening remain controversial, with particular concern that ductal carcinoma in situ (DCIS) may be over-diagnosed and over-treated. There is little prospective data on treatment or outcomes for screen detected DCIS.

Methods:

A prospective cohort of non-invasive lesions diagnosed through the United Kingdom National Health Service Breast Screening Programme (NHSBSP) (1 April 2003 to 31 March 2012) was linked to national databases and case note review to analyse patterns of care, recurrence and mortality.

Results:

Screen-detected DCIS in 9938 women was analysed, 33% (9938/30041) of women with a final diagnosis of non-invasive breast neoplasia diagnosed through the NHSBSP over the same time.

The patients (mean age was 60 years: range 46-87 years) were treated by breast conservation surgery (BCS; 7007; 70.5%) or mastectomy (2931). At 64 months median follow up, 697 (6.8%) had further DCIS or invasive breast cancer after BCS (7.8%) or mastectomy (4.5%) (p&lt;0.001) and 228 women (2.3%) developed contralateral malignancy.

Breast radiotherapy (RT) after BCS (4363/7007; 62%) was associated with a 3.1% absolute reduction in any ipsilateral DCIS or invasive cancer (No RT: 7.2% vs RT: 4.1% (p&lt;0.001) and a 1.9% absolute reduction for ipsilateral invasive breast recurrence (No RT: 3.8% vs RT: 1.9% (p&lt;0.001), independent of excision margin width or size of DCIS. Women who did not receive RT after BCS had more ipsilateral events (p=0.008) when the radial excision margin was &lt;2mm. RT was rarely used after mastectomy for DCIS (33 women). Adjuvant endocrine therapy (prescribed for 1208/9938; 12.2%) was associated with a reduction in any ipsilateral recurrence, independent of whether women did (HR 0.57: 95% CI 0.41 - 0.80) or did not (HR 0.68: 95% CI 0.51 - 0.91) receive RT after BCS.

Among 321 (3.2%) women who died, 46 deaths (0.5%; 14.3% of all deaths) were attributed to invasive breast cancer. Death from breast cancer was uncommon and outnumbered 5:1 by death due to other causes. RT after BCS was associated with a non-significant 0.2% absolute reduction in breast cancer mortality. However, women who developed invasive breast cancer had a worse survival than those with further DCIS (p&lt;0.001).

Conclusions:

Recurrent DCIS or invasive cancer is uncommon following screen detected DCIS treated by surgery and adjuvant therapy. Both RT and endocrine therapy following surgery were associated with a significant reduction in further DCIS and invasive disease, but not breast cancer mortality, within 5 years of diagnosis. This study quantifies the benefits of radiotherapy and endocrine therapy to inform decision making in the management of screen detected DCIS.

Citation Format: Thompson AM, Clements K, Cheung S, Pinder SE, Lawrence G, Sawyer E, Kearins O, Ball GR, Tomlinson I, Hanby AM, Thomas J, Maxwell AJ, Wallis MG, Dodwell DJ. Impact of radiotherapy and endocrine therapy on further events: Final multivariate analysis of a prospective, national cohort study of screen detected ductal carcinoma in situ (DCIS) of the breast [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-02.

Intracytoplasmic sperm injection: state of the art in humans

Among infertile couples, 25% involve both male and female factors, while male factor alone accounts for another 25% due to oligo-, astheno-, teratozoospermia, a combination of the three, or even a complete absence of sperm cells in the ejaculate and can lead to a poor prognosis even with the help of assisted reproductive technology (ART). Intracytoplasmic sperm injection (ICSI) has been with us now for a quarter of a century and in spite of the controversy generated since its inception, it remains in the forefront of the techniques utilized in ART. The development of ICSI in 1992 has drastically decreased the impact of male factor, resulting in millions of pregnancies worldwide for couples who, without ICSI, would have had little chance of having their own biological child. This review focuses on the state of the art of ICSI regarding utility of bioassays that evaluate male factor infertility beyond the standard semen analysis and describes the current application and advances in regard to ICSI, particularly the genetic and epigenetic characteristics of spermatozoa and their impact on reproductive outcome.

Highly heterogeneous diazotroph communities in the Kuroshio Current and the Tokara Strait, Japan

In this study, we used 454-pyrosequencing to report the highly diverse diazotroph communities in the Kuroshio and its adjacent waters along a transect across the Tokara Strait, Japan. Terrestrial input from the islands resulted in a highly heterogeneous diazotroph community within a relatively small geographic region, which was presumably caused by the remarkably different responses of UCYN-A2, UCYN-C and Trichodesmium to the steep environmental gradient. On the other hand, most major cyanobacterial OTUs found in this study were also detected in an unpublished dataset from the upstream Kuroshio, which suggests transportation of diazotrophs by the Kuroshio in large geographic scale. A significant amount of UCYN-C was found in the Kuroshio and offshore stations, suggesting the importance of this potentially overlooked group in the western North Pacific Ocean (WNPO). Moreover, a novel sublineage of UCYN-B was defined, which was predominant in an oligotrophic water sample; and it was also found to be widely distributed in oceanic waters. In addition, the apparent increase in relative abundance of UCYN-A2 from offshore to near-shore water provides evidence for the earlier and under-debating view that UCYN-A2 prefers coastal conditions. Our report provides new knowledge for understanding the phylogeny and ecology of unicellular cyanobacterial diazotrophs in WNPO.

Geographic Distribution of Ammonia-Oxidizing Archaea along the Kuril Islands in the Western Subarctic Pacific

Community composition and abundance of ammonia-oxidizing archaea (AOA) in the ocean were affected by different physicochemical conditions, but their responses to physical barriers (such as a chain of islands) were largely unknown. In our study, geographic distribution of the AOA from the surface photic zone to the deep bathypelagic waters in the western subarctic Pacific adjacent to the Kuril Islands was investigated using pyrosequencing based on the ammonia monooxygenase subunit A (amoA) gene. Genotypes of clusters A and B dominated in the upper euphotic zone and the deep waters, respectively. Quantitative PCR assays revealed that the occurrence and ammonia-oxidizing activity of ammonia-oxidizing archaea (AOA) reached their maxima at the depth of 200 m, where a higher diversity and abundance of actively transcribed AOA was observed at the station located in the marginal sea exposed to more terrestrial input. Similar community composition of AOA observed at the two stations adjacent to the Kuril Islands maybe due to water exchange across the Bussol Strait. They distinct from the station located in the western subarctic gyre, where sub-cluster WCAII had a specific distribution in the surface water, and this sub-cluster seemed having a confined distribution in the western Pacific. Habitat-specific groupings of different WCB sub-clusters were observed reflecting the isolated microevolution existed in cluster WCB. The effect of the Kuril Islands on the phylogenetic composition of AOA between the Sea of Okhotsk and the western subarctic Pacific is not obvious, possibly because our sampling stations are near to the Bussol Strait, the main gateway through which water is exchanged between the Sea of Okhotsk and the Pacific. The vertical and horizontal distribution patterns of AOA communities among stations along the Kuril Islands were essentially determined by the in situ prevailing physicochemical gradients along the two dimensions.

Hemoperitoneum secondary to intercostal arterial bleeding in a trauma patient

Blunt trauma resulting in rib fractures can be associated with hemothorax, pneumothorax, pulmonary contusions or less frequently chest and abdominal wall hematomas. Our case describes the first report of hemoperitoneum secondary to intercostal arterial bleeding from blunt trauma in a patient on anticoagulation.

Spatial Variations of the Methanogenic Communities in the Sediments of Tropical Mangroves

Methane production by methanogens in mangrove sediments is known to contribute significantly to global warming, but studies on the shift of methanogenic community in response to anthropogenic contaminations were still limited. In this study, the effect of anthropogenic activities in the mangrove sediments along the north and south coastlines of Singapore were investigated by pyrosequencing of the mcrA gene. Our results showed that hydrogenotrophic, acetoclastic and methylotrophic methanogens coexist in the sediments. The predominance of the methylotrophic Methanosarcinales reflects the potential for high methane production as well as the possible availability of low acetate and high methylated C-1 compounds as substrates. A decline in the number of acetoclastic/methylotrophic methanogens in favor of hydrogenotrophic methanogens was observed along a vertical profile in Sungei Changi, which was contaminated by heavy metals. The diversity of methanogens in the various contaminated stations was significantly different from that in a pristine St. John's Island. The spatial variation in the methanogenic communities among the different stations was more distinct than those along the vertical profiles at each station. We suggest that the overall heterogeneity of the methanogenic communities residing in the tropical mangrove sediments might be due to the accumulated effects of temperature and concentrations of nitrate, cobalt, and nickel.