The effect of cesarean section on the dimensions and ratios of mons pubis.

BACKGROUND: Pregnancy and labor can impact women's body contours. After a cesarean section, some women may experience aesthetic issues such as the formation of a panniculus and a bulging mons pubis. This study aimed to investigate the impact of cesarean sections on the dimensions of the mons pubis and their ratios. METHODS: The study included 194 multiparous Caucasian women. Participants' ages ranged from 18 to 40 years, and their BMI ranged from 18 to 30. They were divided into two BMI groups. Each group was further subdivided based on the mode of delivery into vaginal delivery (VD) and cesarean section (CS) groups. Manual measurements of the three dimensions of the mons pubis (monal height, monal width, and monal length) were conducted. Measurements were recorded in centimeters in the lithotomy position using iGaging 8-inch digital outside calipers. Monal height is the distance between the anterior surface of the symphysis pubis and the maximum height of the mons pubis (calculated by measuring the distance between the anterior wall of the vagina and the maximum height of the mons pubis minus the distance between the anterior wall of the vagina and the anterior surface of the symphysis pubis). Monal width is the maximum transverse distance between the merging borders of the mons pubis and the fat of the lower abdominal wall. Monal length is the maximum longitudinal distance between the merging upper border of the mons pubis and the fat of the lower abdominal wall and the upper end of the pudendal cleft. RESULTS: No significant statistical difference was observed between the three dimensions of the mons pubis in vaginal delivery and cesarean section populations in the two groups. The changes in the ratios between the two groups' different monal dimensions in the cesarean section population are minimal and do not follow a consistent pattern. There were no significant differences between the dimensions of single and repeated CS populations, with non-trendy changes in the different ratios in the repeated CS group. CONCLUSION: Even when repeated, cesarean section minimally affects the dimensions and ratios of the mons pubis. However, more studies with standardized fascial and subcutaneous fat closure are needed.

Dimensions, Ratios, Volumes, and Weights of the Fatty Parts of the Vulva (Mons Pubis and Labia Majora).

BACKGROUND: The anatomy of the fatty parts of the vulva, specifically the mons pubis and labia majora, has not been extensively studied. OBJECTIVES: This study aimed to provide a comprehensive 3-dimensional picture of the mons pubis and labia majora by defining and measuring their dimensions. Furthermore, the study sought to calculate the different ratios, volumes, and weights of these structures. METHODS: The study included 214 women, who were divided into 2 groups based on their BMI. The researchers defined 27 dimensions to describe the width, height, and length of the mons pubis and labia majora, and specified the measuring methodology. RESULTS: The height of the mons pubis was approximately three-quarters of its length and half its width. The labia majora were wider and taller anteriorly than posteriorly, and their ratios decreased as they went posteriorly, from 4 to 2. The ratio of monal height to maximum labial height and to labial length was 3 and 1, respectively, whereas the ratio of monal width to the sum of maximum labial widths was nearly 1.5. The calculated volumes and weights of the mons pubis and labium majus were 200 mL, 30 mL, 180 g, and 27 g in Group 1, and 300 mL, 40 mL, 270 g, and 36 g in Group 2, respectively. CONCLUSIONS: The dimensions, ratios, weights, and volumes defined and measured in this study can serve as the basis for any aesthetic measures involving the mons pubis and labia majora. Moreover, BMI and the different ratios should be considered in such measures.

Determining the Optimal Time Interval between Vaginal Dinoprostone Administration and Diagnostic Office Hysteroscopy in Nulliparous Women: A Randomized, Double-blind Trial.

STUDY OBJECTIVE: To determine the optimal timing of vaginal dinoprostone administration before office hysteroscopy (OH) in nulliparous women. DESIGN: Randomized, double-blind trial. SETTING: Tertiary referral hospital. PATIENTS: A total of 180 nulliparous women undergoing diagnostic OH. INTERVENTIONS: We randomly allocated the women to long-interval or short-interval dinoprostone groups: three mg dinoprostone was administered vaginally 12 hours before OH in the long-interval group and 3 hours before OH in the short-interval group. MEASUREMENTS AND MAIN RESULTS: The primary outcome was pain during OH measured using a 100-mm visual analog scale (0 = no pain; 100 = worst pain imaginable). The secondary outcomes were ease of hysteroscope passage, patient satisfaction score, and drug-related adverse effects. The patients in the long-interval dinoprostone group had lower pain scores during OH (p <.001). Contrarily, pain scores 30 minutes after the procedure were similar in both groups (p = .1). The patient satisfaction score was higher and clinicians found hysteroscope passage through the cervical canal easier and quicker in the long-interval dinoprostone group than in the short-interval group (p <.001, p = .003, and p <.001, respectively). Side effects were comparable in both study groups. CONCLUSION: Vaginal dinoprostone administered 12 hours before OH was more effective than that administered 3 hours before OH in reducing pain during OH in nulliparous women, with easier hysteroscope insertion, shorter procedure duration, and higher patient satisfaction score.

Warming mediates the resistance of aquatic bacteria to invasion during community coalescence.

The immigration history of communities can profoundly affect community composition. For instance, early-arriving species can have a lasting effect on community structure by reducing the invasion success of late-arriving ones through priority effects. This can be particularly important when early-arriving communities coalesce with another community during dispersal (mixing) events. However, the outcome of such community coalescence is unknown as we lack knowledge on how different factors influence the persistence of early-arriving communities and the invasion success of late-arriving taxa. Therefore, we implemented a full-factorial experiment with aquatic bacteria where temperature and dispersal rate of a better adapted community were manipulated to test their joint effects on the resistance of early-arriving communities to invasion, both at community and population level. Our 16S rRNA gene sequencing-based results showed that invasion success of better adapted late-arriving bacteria equaled or even exceeded what we expected based on the dispersal ratios of the recipient and invading communities suggesting limited priority effects on the community level. Patterns detected at the population level, however, showed that resistance of aquatic bacteria to invasion might be strengthened by warming as higher temperatures (a) increased the sum of relative abundances of persistent bacteria in the recipient communities, and (b) restricted the total relative abundance of successfully established late-arriving bacteria. Warming-enhanced resistance, however, was not always found and its strengths differed between recipient communities and dispersal rates. Nevertheless, our findings highlight the potential role of warming in mitigating the effects of invasion at the population level.

Oral tramadol versus oral celecoxib for analgesia after mediolateral episiotomy repair in obese primigravidae: a randomized controlled trial.

INTRODUCTION AND HYPOTHESIS: A variety of pharmacological and non-pharmacological interventions have been investigated, with the goal of relieving pain after post-episiotomy repair. We aimed to compare the efficacy of tramadol versus celecoxib orally in reducing pain after mediolateral episiotomy repair in obese primigravidae undergoing spontaneous vaginal delivery. METHODS: We conducted a randomized double-blinded trial in Cairo University hospital, Cairo, Egypt, from October 2018 to December 2019. We randomly assigned 200 women into two groups: group A (n = 100) received one tramadol tablet 100 mg orally whereas group B (n = 100) received one celecoxib tablet 200 mg orally. Our primary outcome was pain score using a 10-cm visual analog scale at different time intervals. Our secondary outcomes were the overall satisfaction score and drug side effects. RESULTS: After mediolateral episiotomy repair, the pain scores at 1, 2, and 4 h were significantly lower in the tramadol group than in the celecoxib group (p < 0.001). However, there were no significantly differences in pain scores at 8 and 12 h between the two groups (p = 0.50 and 0.48 respectively). Women's satisfaction score was significantly higher in the tramadol group than in the celecoxib group (p < 0.001). Fewer participants in the tramadol group needed additional analgesics than in the celecoxib group; however, the difference was not significant (p = 0.17). Drug adverse effects were comparable in the two groups. CONCLUSIONS: Primigravid women who received tramadol 100 mg orally after mediolateral episiotomy repair had lower pain scores and were more satisfied than women who received celecoxib 200 mg orally. Both drugs were well tolerated, with few side effects.

Prevalence of vitamin D deficiency in Egyptian patients with pregnancy-induced hypertension.

Background Hypertensive disorders of pregnancy can cause severe maternal and fetal acute morbidity and mortality. Women with pre-eclampsia have been found to have alterations in calcium and vitamin D metabolism. There are conflicting results regarding the role of vitamin D deficiency in the development of pre-eclampsia. The aim was to compare 25 (OH) D level in patients with pre-eclampsia, eclampsia and normotensive pregnant women as well as to study the prevalence of Vitamin D deficiency among the 3 groups. Patients and methods Two hundred patients with pre-eclampsia, 100 with eclampsia and 200 normotensive pregnant controls were compared as regards vitamin D level. Results Mean 25(OH)D level was lower in the pre-eclampsia (14.8 ± 5.4 ng/mL) and in the eclampsia group (10.5 ± 1.6 ng/mL) than in the pregnant controls (19.5 ± 6.5 ng/mL) (P = 0.002). This difference was only significant between the eclampsia group and the pregnant controls (P = 0.02). All eclampsia cases had vitamin D insufficiency as compared to 17.5% in the pre-eclampsia group and 39.5% in the control group. Deficiency of vitamin D (<12 ng/mL) was 47.5% in the pre-eclampsia group, 80% in the eclampsia group and only 10.5% in the control group (P = 0.035). Conclusion Vitamin D deficiency is highly prevalent among Egyptian pregnant females. Our study supports the hypothesis that low vitamin D level can play a role in the development of pre-eclampsia and eclampsia. Thus, supplementation might prevent or delay the development of pre-eclampsia and eclampsia especially in patients at a high risk.

Benefits of vaginal dinoprostone administration prior to levonorgestrel-releasing intrauterine system insertion in women delivered only by elective cesarean section: a randomized double-blinded clinical trial.

PURPOSE: This study aimed at investigating the efficacy and safety of dinoprostone 3 mg vaginally prior to levonorgestrel-releasing intrauterine system (LNG-IUS) insertion in women undergoing elective cesarean delivery (CD). METHODS: We conducted a prospective, randomized, double-blinded, placebo-controlled trial at family planning clinic of Cairo University hospitals from August 2019 to January 2020. We included 200 women aged ≥ 18 years who previously delivered by elective CD willing to receive LNG-IUS. Women were randomly assigned with a 1:1 allocation ratio to receive 3 mg vaginal dinoprostone or placebo tablets two hours before LNG-IUS insertion. Our main outcomes were patient-reported pain during insertion and 30 min post-procedure, ease of insertion, satisfaction, duration of insertion, and different side effects. RESULTS: Patient-perceived pain during LNG-IUS insertion was significantly reduced in dinoprostone compared to placebo (4.1 ± 1.7 vs 6.4 ± 1.3; p < 0.001). Dinoprostone reduced pain scores 30 min post-procedure compared to placebo, but the difference was not statistically significant (3.5 ± 1.1 vs 3.7 ± 1.6; p = 0.25). Satisfaction score was higher in dinoprostone compared to placebo (7.9 ± 1.0 vs 5.9 ± 0.8; p < 0.001). The insertion was significantly easier and shorter in dinoprostone than placebo (3.9 ± 1.1 vs 5.9 ± 1.1; p < 0.001) and (5.6 ± 0.9 vs 7.2 ± 0.8; p < 0.001), respectively. Adverse events were not significantly different between both groups. CONCLUSION: Dinoprostone administration 2 h before LNG-IUS insertion in women delivered by elective CD effectively reduced pain during insertion and 30 min post-procedure. Women received dinoprostone had easier and shorter insertion and were more satisfied with tolerable side effects.

The prevalence of combined vascular endothelial growth factor, endothelial nitric oxide synthase and thrombin-activatable fibrinolysis inhibitor genetic polymorphisms among Egyptian patients with recurrent spontaneous abortion.

AIM: As angiogenesis is an essential step for chorionic villi formation. Vascular endothelial growth factor (VEGF) is essential for endothelial cell proliferation. Endothelial nitric oxide synthase (eNOS) is a powerful playmaker in hypoxia-induced angiogenesis. Thrombin-activatable fibrinolysis inhibitor (TAFI) regulates both fibrinolysis and inflammation. Genetic alterations of these factors may lead to recurrent spontaneous abortion (RSA). We aimed to investigate the combined genetic variants of VEGF G-1154A and two eNOS genetic variants: T-786C promoter region and intron 4 variable number of tandom repeats in addition to TAFI C-1040T among RSA patients. METHODS: The study included 50 patients with RSA and 50 healthy controls. Polymerase chain reaction and restriction fragment length polymorphism were used for genotyping. RESULTS: Both genetic alterations of eNOS confirmed at least a sixfold increase of RSA risk. Interestingly, they were associated with TAFI C-1040Tgenetic variant in 21 patients, eight of them had both studied eNOS genetic alterations and TAFI C-1040Tgenetic variant, while each eNOS genetic variant associated with TAFI C-1040Tconfirmed an almost one and half fold increase risk of RSA. CONCLUSION: These findings highlighted the role of eNOS and nitric oxide metabolism in RSA and opened the gate to investigate the interaction of vasoconstrictive and fibrinolytic inhibitor systems.

Interactions of Freshwater Cyanobacteria with Bacterial Antagonists.

Cyanobacterial and algal mass development, or blooms, have severe effects on freshwater and marine systems around the world. Many of these phototrophs produce a variety of potent toxins, contribute to oxygen depletion, and affect water quality in several ways. Coexisting antagonists, such as cyanolytic bacteria, hold the potential to suppress, or even terminate, such blooms, yet the nature of this interaction is not well studied. We isolated 31 cyanolytic bacteria affiliated with the genera Pseudomonas, Stenotrophomonas, Acinetobacter, and Delftia from three eutrophic freshwater lakes in Sweden and selected four phylogenetically diverse bacterial strains with strong-to-moderate lytic activity. To characterize their functional responses to the presence of cyanobacteria, we performed RNA sequencing (RNA-Seq) experiments on coculture incubations, with an initial predator-prey ratio of 1:1. Genes involved in central cellular pathways, stress-related heat or cold shock proteins, and antitoxin genes were highly expressed in both heterotrophs and cyanobacteria. Heterotrophs in coculture expressed genes involved in cell motility, signal transduction, and putative lytic activity. l,d-Transpeptidase was the only significantly upregulated lytic gene in Stenotrophomonas rhizophila EK20. Heterotrophs also shifted their central metabolism from the tricarboxylic acid cycle to the glyoxylate shunt. Concurrently, cyanobacteria clearly show contrasting antagonistic interactions with the four tested heterotrophic strains, which is also reflected in the physical attachment to their cells. In conclusion, antagonistic interactions with cyanobacteria were initiated within 24 h, and expression profiles suggest varied responses for the different cyanobacteria and studied cyanolytes.IMPORTANCE Here, we present how gene expression profiles can be used to reveal interactions between bloom-forming freshwater cyanobacteria and antagonistic heterotrophic bacteria. Species-specific responses in both heterotrophs and cyanobacteria were identified. The study contributes to a better understanding of the interspecies cellular interactions underpinning the persistence and collapse of cyanobacterial blooms.

Effects of multiple dimensions of bacterial diversity on functioning, stability and multifunctionality.

Bacteria are essential for many ecosystem services but our understanding of factors controlling their functioning is incomplete. While biodiversity has been identified as an important driver of ecosystem processes in macrobiotic communities, we know much less about bacterial communities. Due to the high diversity of bacterial communities, high functional redundancy is commonly proposed as explanation for a lack of clear effects of diversity. The generality of this claim has, however, been questioned. We present the results of an outdoor dilution-to-extinction experiment with four lake bacterial communities. The consequences of changes in bacterial diversity in terms of effective number of species, phylogenetic diversity, and functional diversity were studied for (1) bacterial abundance, (2) temporal stability of abundance, (3) nitrogen concentration, and (4) multifunctionality. We observed a richness gradient ranging from 15 to 280 operational taxonomic units (OTUs). Individual relationships between diversity and functioning ranged from negative to positive depending on lake, diversity dimension, and aspect of functioning. Only between phylogenetic diversity and abundance did we find a statistically consistent positive relationship across lakes. A literature review of 24 peer-reviewed studies that used dilution-to-extinction to manipulate bacterial diversity corroborated our findings: about 25% found positive relationships. Combined, these results suggest that bacteria-driven community functioning is relatively resistant to reductions in diversity.

Gene expression profiling of endometrium versus bone marrow-derived mesenchymal stem cells: upregulation of cytokine genes.

Postulated Stem/progenitor cells involved in endometrium regeneration are epithelial, mesenchymal, and endothelial. Bone marrow (BM) has been implicated in endometrial stem cells. We aimed at studying gene expression profiling of endometrial mesenchymal stem cells compared to BM MSCS to better understand their nature and functional phenotype. Endometrial tissues were obtained from premenopausal hysterectomies (n = 3), minced and enzymatically digested as well as Normal BM aspirates (n=3). Immunophenotyping, differentiation to mesoderm, and proliferation were studied. The expression profile of 84 genes relevant to mesenchymal stem cells was performed. Fold change calculations were determined with SA Biosciences data analysis software. VEGF, G-CSF, and GM-CSF in cultures supernatants of MSCs were assayed by Luminex immunoassay. Endo MSCs possess properties similar to BM MSCs. Cumulative population doubling was significantly higher in Endo MSCs compared to BM MSCs (p < 0.001). 52 core genes were shared between both generated MSCs including stemness, self-renewal, members of the Notch, TGFB, FGF, and WNT.16 downregulated genes (VCAM, IGF1)and 16 upregulated in Endo MSCs compared to BM (p < 0.05 â†’ fourfolds). They included mostly cytokine and growth factor genes G-CSF, GM-CSF, VWF, IL1b, GDF15, and KDR. VEGF and G-CSF levels were higher in Endo MSCs supernatants (p < 0.0001). Cells sharing MSC and endothelial cell characteristics could be isolated from the human endometrium. Endo MSCs share a core genetic profile with BM MSCs including stemness. They show upregulation of genes involved in vasculogenesis, angiogenesis, cell adhesion, growth proliferation, migration, and differentiation of endothelial cells, all contributing to endometrial function.

Evaluation of cytokines in follicular fluid and their effect on fertilization and pregnancy outcome.

Cytokines in follicular fluid (FF) are important for reproduction as they modulate oocyte maturation and ovulation which influence subsequent fertilization, development of early embryo and potential for implantation. We evaluated FF cytokines in women who underwent intracytoplasmic sperm injection (ICSI) and their association with fertilized oocytes, embryo quality and pregnancy outcome. FF belonging to 38 patients including 18 polycystic ovary (PCO) and 20 male/unexplained infertility patients were investigated for granulocyte colony stimulating factor (G-CSF), regulated upon activation normal T cell expressed and presumably secreted (RANTES), tumour necrosis factor (TNFα), interferon gamma (IFNγ) and interleukins (IL-4 and IL-2) by bead-based sandwich immunoassay. Our findings revealed that on the day of oocyte retrieval, G-CSF was positively correlated with the number of fertilized oocytes, while TNFα detection was associated with reduced number of fertilized oocytes. Only G-CSF showed significant positive effect to the pregnancy outcome although the cytokines studied were not associated with embryo quality. PCO as the cause of infertility did not show an association with cytokines in FF. The functions of cytokines in reproduction are likely to be complex, and cytokine evaluation may offer insight to the understanding of the mechanisms leading to success or failure of assisted reproduction.

Detecting aquatic pathogens with field-compatible dried qPCR assays.

Field-ready qPCR assays with extended shelf-life support monitoring programs for emerging aquatic pathogens and enable quick conservation and management decisions. Here, we developed, validated, and tested the shelf-life of qPCR assays targeting Gyrodactylus salaris and Aphanomyces astaci with lyophilization and air-drying.

Functionally reversible impacts of disturbances on lake food webs linked to spatial and seasonal dependencies.

Increasing human impact on the environment is causing drastic changes in disturbance regimes and how they prevail over time. Of increasing relevance is to further our understanding on biological responses to pulse disturbances (short duration) and how they interact with other ongoing press disturbances (constantly present). Because the temporal and spatial contexts of single experiments often limit our ability to generalize results across space and time, we conducted a modularized mesocosm experiment replicated in space (five lakes along a latitudinal gradient in Scandinavia) and time (two seasons, spring and summer) to generate general predictions on how the functioning and composition of multitrophic plankton communities (zoo-, phyto- and bacterioplankton) respond to pulse disturbances acting either in isolation or combined with press disturbances. As pulse disturbance, we used short-term changes in fish presence, and as press disturbance, we addressed the ongoing reduction in light availability caused by increased cloudiness and lake browning in many boreal and subarctic lakes. First, our results show that the top-down pulse disturbance had the strongest effects on both functioning and composition of the three trophic levels across sites and seasons, with signs for interactive impacts with the bottom-up press disturbance on phytoplankton communities. Second, community composition responses to disturbances were highly divergent between lakes and seasons: temporal accumulated community turnover of the same trophic level either increased (destabilization) or decreased (stabilization) in response to the disturbances compared to control conditions. Third, we found functional recovery from the pulse disturbances to be frequent at the end of most experiments. In a broader context, these results demonstrate that top-down, pulse disturbances, either alone or with additional constant stress upon primary producers caused by bottom-up disturbances, can induce profound but often functionally reversible changes across multiple trophic levels, which are strongly linked to spatial and temporal context dependencies. Furthermore, the identified dichotomy of disturbance effects on the turnover in community composition demonstrates the potential of disturbances to either stabilize or destabilize biodiversity patterns over time across a wide range of environmental conditions.

Evaluating efficacy of intravenous carbetocin in reducing blood loss during abdominal myomectomy: a randomized controlled trial.

OBJECTIVE: To evaluate the efficacy of carbetocin versus placebo in decreasing intraoperative blood loss and the need for blood transfusion during abdominal myomectomy. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Tertiary university hospital from September 2019 to February 2020. PATIENT(S): A total of 138 women with symptomatic leiomyoma who were candidates for abdominal myomectomy (n = 69 in each group). INTERVENTION(S): We randomized the study participants in a 1:1 ratio to carbetocin and placebo groups. Intravenous 100 µg carbetocin or placebo was administered slowly after induction of anesthesia. MAIN OUTCOME MEASURE(S): Intraoperative blood loss, need for blood transfusion, postoperative hemoglobin, operative time, length of hospitalization, and drug side-effects. RESULT(S): The baseline characteristics were similar among all groups. Carbetocin had significantly lower intraoperative blood loss compared with placebo (mean difference 184 mL). Hemoglobin level 24 hours after surgery was significantly lower in the placebo group than in the carbetocin group (9.1 ± 0.8 vs. 10.3 ± 0.6 g/dL). Eight women in the carbetocin group needed blood transfusion compared with 17 in placebo group. Operative time, length of hospitalization, and side-effects were similar in both groups. CONCLUSION(S): A single preoperative intravenous dose of 100 µg carbetocin is a simple, practical, and effective method of decreasing intraoperative blood loss and the need for blood transfusion during abdominal myomectomy, with tolerable, few, nonsignificant side-effects. CLINICAL TRIAL REGISTRATION NUMBER: NCT04083625.

Evaluation of the Cesarean Scar Niche In Women With Secondary Infertility Undergoing ICSI Using 2D Sonohysterography Versus 3D Sonohysterography and Setting a Standard Criteria; Alalfy Simple Rules for Scar Assessment by Ultrasound To Prevent Health Problems for Women.

BACKGROUND: Many expressions were used to define the defect that is seen by ultrasound after cesarean section (CS) namely scar defect, niche, isthmocele, uterine pouch or diverticula. OBJECTIVE: To compare the accuracy of 2 dimensional sonohysterography (2D SHG) to 3 dimensional sonohysterography (3D SHG) in evaluating cesarean section uterine scar depth (D), base width (BW), width (W) and residual myometrial thickness (RMT) in women with secondary infertility and establishment of a standard criteria; Alalfy simple rules for scar assessment. PATIENTS AND METHODS: This was an observational cross-sectional comparative study that was conducted on women who presented with secondary infertility and were candidates for intracytoplasmic sperm injection (ICSI) and giving a history of a previous cesarean section. Assessment of uterine scar in each woman was performed using 2D transvaginal ultrasound with sonohysterography (SHG) followed by 3D transvaginal with SHG with evaluation of niche depth, width, RMT, niche BW and RMT/depth ratio. The study was conducted at Algezeera hospital, Egypt. RESULTS: The present study revealed that 3D ultrasound with SHG is superior in evaluation of the RMT and niche width prior to ICSI providing better characterization of the scar niche. CONCLUSION: Scar niche should be assessed by a combined integrated 2D SHG and 3D SHG scan with the specific geometrical and anatomical considerations, Alalfy simple rules for scar niche assessment that involvemeasurement of niche depth, (Base width) BW, width, RMT and RMT/depth ratio in sagittal plane, RMT in coronal plane / niche width in coronal plane ratio (ratio less than 1 denotes scar weakness with more liability for dehiscence). TRIAL REGISTRATION: Clinical Trials.gov Id NCT04076904.

Dispersal timing determines the importance of priority effects in bacterial communities.

The order and timing of species arrival during community assembly can have long term effects on community structure due to priority effects. The importance of such processes in complex bacterial communities where dispersal involves mixing of entire communities is currently not known. Here we used a transplant experiment with two bacterioplankton communities of different origin (freshwater and brackish). Sterile medium of each origin was initially inoculated with a bacterial community of different ('alien') origin, followed by dispersal of the respective 'home' community at different time points after initial inoculation. We found that the later the dispersal with the 'home' community occurred the smaller the effect on the final community composition. This suggests that priority effects by the initially inoculated community reduce the establishment success of taxa from the later arriving community and that this effect depends on dispersal timing.

Formation of mercury methylation hotspots as a consequence of forestry operations.

Earlier studies have shown that boreal forest logging can increase the concentration and export of methylmercury (MeHg) in stream runoff. Here we test whether forestry operations create soil environments of high MeHg net formation associated with distinct microbial communities. Furthermore, we test the hypothesis that Hg methylation hotspots are more prone to form after stump harvest than stem-only harvest, because of more severe soil compaction and soil disturbance. Concentrations of MeHg, percent MeHg of total Hg (THg), and bacterial community composition were determined at 200 soil sampling positions distributed across eight catchments. Each catchment was either stem-only harvested (n=3), stem- and stump-harvested (n=2) or left undisturbed (n=3). In support of our hypothesis, higher MeHg to THg ratios was observed in one of the stump-harvested catchments. While the effects of natural variation could not be ruled out, we noted that most of the highest % MeHg was observed in water-filled cavities created by stump removal or driving damage. This catchment also featured the highest bacterial diversity and highest relative abundance of bacterial families known to include Hg methylators. We propose that water-logged and disturbed soil environments associated with stump harvest can favor methylating microorganisms, which also enhance MeHg formation.

Emerging microbiota during cold storage and temperature abuse of ready-to-eat salad​.

Introduction: Ready-to-eat (RTE) leafy vegetables have a natural leaf microbiota that changes during different processing and handling steps from farm to fork. The objectives of this study were (i) to compare the microbiota of RTE baby spinach and mixed-ingredient salad before and after seven days of storage at 8°C or 15°C; (ii) to explore associations between bacterial communities and the foodborne pathogens Listeria monocytogenes, pathogenic Yersinia enterocolitica, and pathogen model organism Escherichia coli O157:H7 gfp+ when experimentally inoculated into the salads before storage; and (iii) to investigate if bacterial pathogens may be detected in the 16S rRNA amplicon dataset. Material and methods: The microbiota was studied by means of Illumina 16S rRNA amplicon sequencing. Subsets of samples were inoculated with low numbers (50-100 CFU g-1) of E. coli O157:H7 gfp+, pathogenic Y. enterocolitica or L. monocytogenes before storage. Results and discussion: The composition of bacterial communities changed during storage of RTE baby spinach and mixed-ingredient salad, with Pseudomonadales as the most abundant order across all samples. Although pathogens were present at high viable counts in some samples, they were only detected in the community-wide dataset in samples where they represented approximately 10% of total viable counts. Positive correlations were identified between viable counts of inoculated strains and the abundance of Lactobacillales, Enterobacteriales, and Bacillales, pointing to positive interactions or similar environmental driver variables that may make it feasible to use such bacterial lineages as indicators of microbial health hazards in leafy vegetables. The data from this study contribute to a better understanding of the bacteria present in RTE salads and may help when developing new types of biocontrol agents.​.

Early-Life Human Microbiota Associated With Childhood Allergy Promotes the T Helper 17 Axis in Mice.

The intestinal microbiota influences immune maturation during childhood, and is implicated in early-life allergy development. However, to directly study intestinal microbes and gut immune responses in infants is difficult. To investigate how different types of early-life gut microbiota affect immune development, we collected fecal samples from children with different allergic heredity (AH) and inoculated germ-free mice. Immune responses and microbiota composition were evaluated in the offspring of these mice. Microbial composition in the small intestine, the cecum and the colon were determined by 16S rRNA sequencing. The intestinal microbiota differed markedly between the groups of mice, but only exposure to microbiota associated with AH and known future allergy in children resulted in a T helper 17 (Th17)-signature, both systemically and in the gut mucosa in the mouse offspring. These Th17 responses could be signs of a particular microbiota and a shift in immune development, ultimately resulting in an increased risk of allergy.