Stress- and phospholipid signalling responses in Arabidopsis PLC4-KO and -overexpression lines under salt- and osmotic stress

Several drought and salt tolerant phenotypes have been reported when overexpressing (OE) phospholipase C (PLC) genes across plant species. In contrast, a negative role for Arabidopsis PLC4 in salinity stress was recently proposed, showing that roots of PLC4-OE seedlings were more sensitive to NaCl while plc4 knock-out (KO) mutants were more tolerant. To investigate this apparent contradiction, and to analyse the phospholipid signalling responses associated with salinity stress, we performed root growth- and phospholipid analyses on plc4-KO and PLC4-OE seedlings subjected to salinity (NaCl) or osmotic (sorbitol) stress and compared these with wild type (WT). Only very minor differences between PLC4 mutants and WT were observed, which even disappeared after normalization of the data, while in soil, PLC4-OE plants were clearly more drought tolerant than WT plants, as was found earlier when overexpressing Arabidopsis PLC2, -3, -5, -7 or -9. We conclude that PLC4 plays no opposite role in salt-or osmotic stress and rather behaves like the other Arabidopsis PLCs.

The dynamics of touch-responsive gene expression in cereals

Wind, rain, herbivores, obstacles, neighbouring plants, etc. provide important mechanical cues to steer plant growth and survival. Mechanostimulation to stimulate yield and stress resistance of crops is of significant research interest, yet a molecular understanding of transcriptional responses to touch is largely absent in cereals. To address this, we performed whole-genome transcriptomics following mechanostimulation of wheat, barley, and the recent genome-sequenced oat. The largest transcriptome changes occurred ±25 min after touching, with most of the genes being upregulated. While most genes returned to basal expression level by 1-2 h in oat, many genes retained high expression even 4 h post-treatment in barley and wheat. Functional categories such as transcription factors, kinases, phytohormones, and Ca2+ regulation were affected. In addition, cell wall-related genes involved in (hemi)cellulose, lignin, suberin, and callose biosynthesis were touch-responsive, providing molecular insight into mechanically induced changes in cell wall composition. Furthermore, several cereal-specific transcriptomic footprints were identified that were not observed in Arabidopsis. In oat and barley, we found evidence for systemic spreading of touch-induced signalling. Finally, we provide evidence that both the jasmonic acid-dependent and the jasmonic acid-independent pathways underlie touch-signalling in cereals, providing a detailed framework and marker genes for further study of (a)biotic stress responses in cereals.

MCU proteins dominate in vivo mitochondrial Ca2+ uptake in Arabidopsis roots

Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.

OC-014 FAVOURABLE OUTCOMES AFTER RETRO-RECTUS (RIVES-STOPPA) MESH REPAIR AS TREATMENT FOR NON-COMPLEX VENTRAL ABDOMINAL WALL HERNIA, A SYSTEMATIC REVIEW AND META-ANALYSIS

Aim

Ventral abdominal wall hernia is a common problem, tied to increasing frailty and obesity of patients undergoing surgery. For noncomplex ventral hernia, retro-rectus (Rives-Stoppa) repair is considered the gold standard. Level-1 evidence confirming this presumed superiority is lacking. The aim of this study was to assess prevalence of hernia recurrence, surgical site infection (SSI), seroma, serious complications, and mortality.

Material & Methods

Five databases were searched for studies reporting retro-rectus repair. Randomized and non-randomized studies were included. Outcomes were pooled with random-effects models.

Results

Ninety-three studies representing 12,440 patients undergoing retro-rectus repair were included. Pooled hernia recurrence was estimated at 3.2% [95% confidence interval (CI): 2.2%–4.2%, n = 11,049] after minimally 12 months and 4.1%, (95%CI: 2.9%–5.5%, n = 3830) after minimally 24 months. Incidences of SSI and seroma were estimated at respectively 5.2% (95%CI: 4.2%–6.4%, n = 4891) and 5.5% (95%CI: 4.4%–6.8%, n = 3650). Retro-rectus repair was associated with lower recurrence rates compared to onlay repair (odds ratios (OR): 0.27, 95%CI: 0.15–0.51, P < 0.001) and equal recurrence rates compared to intraperitoneal onlay mesh (IPOM) repair (OR: 0.92, 95%CI: 0.75–1.12, p = 0.400). Retro-rectus repair was associated with more SSI than IPOM repair (OR: 1.8, 95%CI: 1.03–3.14, p = 0.038). Minimally invasive retro-rectus repair displayed low rates of recurrence (1.3%) and SSI (1.5%), albeit based on non-randomized studies.

Conclusions

Retro-rectus repair results in excellent outcomes, superior or similar to other techniques for all outcomes except SSI. The latter occurred less after IPOM repair, which is usually laparoscopic.

Characterization of Histone H3 Gene Family Reveals That GmHH3-3 is Associated With Higher Seed Weight in Glycine max

The main function of histone protein is to provide support to the structure of chromosomes. It helps in binding a long thread of DNA into a more condensed shape to fit into the nucleus. From histone variants, histone H3 (HH3) plays a crucial role in plant growth and development. Characterization of histones has not been reported in Glycine max till now. The objective of this study was to characterize the HH3 gene family for molecular breeding of G. max. In this study, 17 HH3 members in G. max were identified by performing local BLASTp using HH3 members from Arabidopsis as a query. Phylogenetic analysis classified HH3 genes in seven clades. Sequence logo analysis among Arabidopsis thaliana, Oryza sativa, and Glycine max showed a higher level of similarity in amino acids. Furthermore, conserveness of G. max HH3 genes was also confirmed by Gene Structure Display. Ten paralogous gene pairs were identified in GmHH3 genes in the Glycine max genome by conducting collinearity analysis. G. max HH3 genes have experienced strong purifying selection pressure, with limited functional divergence originating from the segmental and whole-genome duplication, as evidenced by the Ka/Ks ratio. The KASP marker was developed for GmHH3-3 gene. Genotyping was performed on 46 G. max genotypes. This differentiation was based upon the presence of either GmHH3-3-C or GmHH3-3-T allele in the CDS region. The results showed that G. max accessions containing the GmHH3-3-T allele at respective locus showed higher thousand seed weight than that of those accessions that contain the GmHH3-3-C allele. This research provides the basic information to further decipher the function of HH3 in soybean.

Touch signaling and thigmomorphogenesis are regulated by complementary CAMTA3- and JA-dependent pathways

Plants respond to mechanical stimuli to direct their growth and counteract environmental threats. Mechanical stimulation triggers rapid gene expression changes and affects plant appearance (thigmomorphogenesis) and flowering. Previous studies reported the importance of jasmonic acid (JA) in touch signaling. Here, we used reverse genetics to further characterize the molecular mechanisms underlying touch signaling. We show that Piezo mechanosensitive ion channels have no major role in touch-induced gene expression and thigmomorphogenesis. In contrast, the receptor-like kinase Feronia acts as a strong negative regulator of the JA-dependent branch of touch signaling. Last, we show that calmodulin-binding transcriptional activators CAMTA1/2/3 are key regulators of JA-independent touch signaling. CAMTA1/2/3 cooperate to directly bind the promoters and activate gene expression of JA-independent touch marker genes like TCH2 and TCH4. In agreement, camta3 mutants show a near complete loss of thigmomorphogenesis and touch-induced delay of flowering. In conclusion, we have now identified key regulators of two independent touch-signaling pathways.

Phenotyping Tomato Root Developmental Plasticity in Response to Salinity in Soil Rhizotrons

Plants have developed multiple strategies to respond to salt stress. In order to identify new traits related to salt tolerance, with potential breeding application, the research focus has recently been shifted to include root system architecture (RSA) and root plasticity. Using a simple but effective root phenotyping system containing soil (rhizotrons), RSA of several tomato cultivars and their response to salinity was investigated. We observed a high level of root plasticity of tomato seedlings under salt stress. The general root architecture was substantially modified in response to salt, especially with respect to position of the lateral roots in the soil. At the soil surface, where salt accumulates, lateral root emergence was most strongly inhibited. Within the set of tomato cultivars, H1015 was the most tolerant to salinity in both developmental stages studied. A significant correlation between several root traits and aboveground growth parameters was observed, highlighting a possible role for regulation of both ion content and root architecture in salt stress resilience.

The effectiveness and safety of introducing condom-catheter uterine balloon tamponade for postpartum haemorrhage at secondary level hospitals in Uganda, Egypt and Senegal: a stepped wedge, cluster-randomised trial

OBJECTIVE

To assess the effectiveness of introducing condom-catheter uterine balloon tamponade (UBT) for postpartum haemorrhage (PPH) management in low- and middle-income settings.

DESIGN

Stepped wedge, cluster-randomised trial.

SETTING

Eighteen secondary-level hospitals in Uganda, Egypt and Senegal.

POPULATION

Women with vaginal delivery from October 2016 to March 2018.

METHODS

Use of condom-catheter UBT for PPH management was introduced using a half-day training and provision of pre-packaged UBT kits. Hospitals were randomised to when UBT was introduced. The incident rate (IR) of study outcomes was compared in the control (i.e. before UBT) and intervention (i.e. after UBT) periods. Mixed effects regression models accounted for clustering (random effect) and time period (fixed effect).

MAIN OUTCOME MEASURES

Combined IR of PPH-related invasive surgery and/or maternal death.

RESULTS

There were 28 183 and 31 928 deliveries in the control and intervention periods, respectively. UBT was used for 9/1357 and 55/1037 women diagnosed with PPH in control and intervention periods, respectively. PPH-related surgery or maternal death occurred in 19 women in the control period (IR = 6.7/10 000 deliveries) and 37 in the intervention period (IR = 11.6/10 000 deliveries). The adjusted IR ratio was 4.08 (95% confidence interval 1.07-15.58). Secondary outcomes, including rates of transfer and blood transfusion, were similar in the trial periods.

CONCLUSIONS

Introduction of condom-catheter UBT in these settings did not improve maternal outcomes and was associated with an increase in the combined incidence of PPH-related surgery and maternal death. The lack of demonstrated benefit of UBT introduction with respect to severe outcomes warrants reflection on its role.

TWEETABLE ABSTRACT

Stepped wedge trial shows UBT introduction does not reduce the combined incidence of PPH-related surgery or death.

Towards an optimal luteal support modality in agonist triggered cycles: a randomized clinical trial

STUDY QUESTION

In ICSI patients with high risk of ovarian hyperstimulation syndrome (OHSS), are antagonist cycles triggered by gonadotropin releasing hormone (GNRH) agonist with a specialized luteal support regimen associated with comparable ongoing pregnancy rate (OPR) and less OHSS than those triggered by hCG?

SUMMARY ANSWER

In antagonist ICSI cycles, GnRH agonist triggering with a specialized luteal support regimen is associated with comparable OPR to those triggered by hCG but may be less likely to be associated with OHSS.

WHAT IS KNOWN ALREADY

In IVF/ICSI protocols, exogenous hCG was used for years as a substitute of the endogenous LH surge. However, because of its longer half life, hCG is associated with more risk of OHSS, especially in high risk women. For this reason, GnRH agonist triggering was introduced. There is, however, no consensus on the best protocol for luteal support on agonist triggered cycles.

STUDY DESIGN, SIZE, DURATION

Randomized controlled open label trial including 190 participants recruited from June 2015 to March 2016 in a private fertility center. Participants were divided into 2 equal groups; GnRH agonist trigger and hCG trigger. Randomization was done using identical sealed envelope technique.

PARTICIPANTS/MATERIALS, SETTING, METHODS

One hundred ninety women, predicted to have high response, were randomized on the day of final oocyte maturation into two equal groups: group (A), GnRH agonist trigger followed by specialized regimen (1500 IU hCG) at time of oocyte retrieval plus oral estradiol and intramuscular progesterone during luteal phase; and group (B), 5000 IU of hCG with luteal support (oral estradiol and vaginal progesterone).

MAIN RESULTS AND THE ROLE OF CHANCE

The 2 groups were comparable in baseline characteristics. OPR per randomized patient was comparable in the 2 groups {49/95 (51.6%) in group A, and 50/95 (52.6%) in group B ((P = 0.88); RR = 0.980, 95% CI: 0.75-1.29)}. Considerable (moderate + severe) OHSS was higher in group B (13/95 [14%] versus 5/95 [5%] P = 0.047; uncorrected Chi-square test). Upon performing multivariate regression analysis for predicting OHSS, number of follicles ≥11 mm on trigger day was the only independent predictor (P = 0.0004).

LIMITATIONS, REASONS FOR CAUTION

Strict selection criteria limit generalization of results. The study was powered for pregnancy rate not OHSS, so that the strength of evidence on OHSS prediction is weak.

WIDER IMPLICATIONS OF THE FINDINGS

We recommend the use of GnRH agonist plus the specialized luteal phase support in high responders with high risk of OHSS undergoing IVF/ICSI cycles. This protocol achieved a similar ongoing pregnancy to hCG triggering and may be less likely to result in moderate to severe OHSS.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

PACTR 201506001132105.

TRIAL REGISTRATION DATE

24/6/2015.

DATE OF FIRST PATIENT’S ENROLLMENT

26/6/2015.

Halotropism is a response of plant roots to avoid a saline environment

Tropisms represent fascinating examples of how plants respond to environmental signals by adapting their growth and development. Here, a novel tropism is reported, halotropism, allowing plant seedlings to reduce their exposure to salinity by circumventing a saline environment. In response to a salt gradient, Arabidopsis, tomato, and sorghum roots were found to actively prioritize growth away from salinity above following the gravity axis. Directionality of this response is established by an active redistribution of the plant hormone auxin in the root tip, which is mediated by the PIN-FORMED 2 (PIN2) auxin efflux carrier. We show that salt-induced phospholipase D activity stimulates clathrin-mediated endocytosis of PIN2 at the side of the root facing the higher salt concentration. The intracellular relocalization of PIN2 allows for auxin redistribution and for the directional bending of the root away from the higher salt concentration. Our results thus identify a cellular pathway essential for the integration of environmental cues with auxin-regulated root growth that likely plays a key role in plant adaptative responses to salt stress.

Heat stress activates phospholipase D and triggers PIP accumulation at the plasma membrane and nucleus

Heat stress induces an array of physiological adjustments that facilitate continued homeostasis and survival during periods of elevated temperatures. Here, we report that within minutes of a sudden temperature increase, plants deploy specific phospholipids to specific intracellular locations: phospholipase D (PLD) and a phosphatidylinositolphosphate kinase (PIPK) are activated, and phosphatidic acid (PA) and phosphatidylinositol 4,5-bisphosphate (PIP(2)) rapidly accumulate, with the heat-induced PIP(2) localized to the plasma membrane, nuclear envelope, nucleolus and punctate cytoplasmic structures. Increases in the steady-state levels of PA and PIP(2) occur within several minutes of temperature increases from ambient levels of 20-25 degrees C to 35 degrees C and above. Similar patterns were observed in heat-stressed Arabidopsis seedlings and rice leaves. The PA that accumulates in response to temperature increases results in large part from the activation of PLD rather than the sequential action of phospholipase C and diacylglycerol kinase, the alternative pathway used to produce this lipid. Pulse-labelling analysis revealed that the PIP(2) response is due to the activation of a PIPK rather than inhibition of a lipase or a PIP(2) phosphatase. Inhibitor experiments suggest that the PIP(2) response requires signalling through a G-protein, as aluminium fluoride blocks heat-induced PIP(2) increases. These results are discussed in the context of the diverse cellular roles played by PIP(2) and PA, including regulation of ion channels and the cytoskeleton.

Phospholipid signaling responses in salt-stressed rice leaves

Salinity is one of the major environmental factors limiting growth and productivity of rice plants. In this study, the effect of salt stress on phospholipid signaling responses in rice leaves was investigated. Leaf cuts were radiolabeled with 32P-orthophosphate and the lipids extracted and analyzed by thin-layer chromatography, autoradiography and phosphoimaging. Phospholipids were identified by co-migration of known standards. Results showed that 32P(i) was rapidly incorporated into the minor lipids, phosphatidylinositol bisphosphate (PIP2) and phosphatidic acid (PA) and, interestingly, also into the structural lipids phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), which normally label relatively slowly, like phosphatidylcholine (PC) and phosphatidylinositol (PI). Only very small amounts of PIP2 were found. However, in response to salt stress (NaCl), PIP2 levels rapidly (<30 min) increased up to 4-fold, in a time- and dose-dependent manner. PA and its phosphorylated product, diacylglycerolpyrophosphate (DGPP), also increased upon NaCl stress, while cardiolipin (CL) levels decreased. All other phospholipid levels remained unchanged. PA signaling can be generated via the combined action of phospholipase C (PLC) and diacylglycerol kinase (DGK) or directly via phospholipase D (PLD). The latter can be measured in vivo, using a transphosphatidylation assay. Interestingly, these measurements revealed that salt stress inhibited PLD activity, indicating that the salt stress-induced PA response was not due to PLD activity. Comparison of the 32P-lipid responses in salt-tolerant and salt-sensitive cultivars revealed no significant differences. Together these results show that salt stress rapidly activates several lipid responses in rice leaves but that these responses do not explain the difference in salt tolerance between sensitive and tolerant cultivars.

Structure and sensory equipment of the ovipositor of Habrobracon hebetor (Say) (Hymenoptera: Braconidae)

The microsculpture of various structures of the ovipositor of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is described from scanning and transmission electron microscopy. These include: the ovipositor egg canal, valvillus, seal of the first valvulae, interlocking mechanism (olistheter) connecting the first and second valvulae, an olistheter-like interlocking mechanism connecting the two pieces of the first valvulae, annulation, microtrichia of the third valvulae, and the ovipositor sensory equipment. Better understanding of the microsculpture of these components may make their roles in stinging, oviposition, and the host selection process more clear.

Pathogenicity of two entomopathogenic hyphomycetes, Beauveria bassiana and Metarhizium anisopliae, to the housefly Musca domestica L

The pathogenicity of three isolates of Metarhizium anisopliae and two isolates Beauveria bassiana originating from different insect species and localities was tested against housefly larvae. Only one isolate of M. anisopliae (Ma23) and the two isolates of B. bassiana (Bb2, Bb108) significantly (P<0.05) reduced the percentage of emerging adults. At the highest tested concentration 10(7) spores/ml. the reduction in the percentage of adult emergence was 93.8%. 61.3% and 49% for Bb2. Ma23 and Bb108. respectively. Based on the IC50 values Bb2 was the most virulent isolate followed by Ma23 and Bb108, (1.13. 1.7 and 4 x 10(6). respectively). The ability of adult flies to pick up conidiospores from contaminated media as well as the possibility of isolate recycling through cadavers of fungus-killed adults were also investigated. Adults were able to pick up conidiospores from the contaminated media. All contaminated adult cadavers subsequently sporulated when placed under high relative humidity conditions. When adult flies were exposed to mycotised cadavers 12. 75 and 76% of the adults exposed to Bb2, Ma23 and Bb108, respectively sporulated under high relative humidity conditions.

Management of severe preeclampsia detected in early labor by prostaglandin A1 or dihydralazine infusions

The presence of severe pregnancy-induced hypertension at the onset of labor requires therapy with a potent hypotensive agent. Prostaglandin A1 is a powerful vasodepressor that augments renal blood flow and glomerular filtration and possesses antiplatelet aggregator and oxytocic properties. A continuous intravenous infusion of prostaglandin A1 (40 to 50 micrograms/min) or dihydralazine (35 to 50 micrograms/min) was administered to 20 women with severe preeclampsia (10 in each group). The induced hypotensive response was similar with both drugs but the maximum reduction in blood pressure was achieved sooner with dihydralazine (4 hours) compared with prostaglandin A1 (7.5 hours). The more gradual hypotensive response is probably less dangerous on placental perfusion than a sudden change. Moreover, the oxytocic property of prostaglandin A1 shortened the time to delivery, which constitutes another potential advantage.

Urinary hormonal profile during the first cycle of low-dose oral contraceptive pills in women

Ovarian function was studied in ten normal fertile women before and during the first cycle on a low-dose micropill containing 30 mcg ethinyl estradiol and 150 mcg L-norgestrel. In a control cycle and the first treatment cycle, steroid metabolites estrone-3-glucuronide (E1-3G) and pregnanediol-3 alpha-glucuronide (Pd-3G) were measured in daily early morning urine (EMU) samples. Also, luteinizing hormone (LH) was estimated during the expected periovulatory period. During the first cycle of micropill intake, ovarian function was suppressed in all cases. This is evidenced by significantly lower E1-3G and Pd-3G and absent midcycle LH peak compared to control cycles. The pattern of steroid metabolites was almost flat with no peaks. It is concluded that there is no need to cover the first cycle of micropill intake with other contraceptive methods.

Cervical prostaglandin injection: a novel method of administration for ripening the cervix and induction of labor

Twenty pregnant women with greater than or equal to 36 weeks gestation and Bishop score of less than or equal to 4 were subjected to either intracervical injection of PGE2 (0.25 mg) every 4 h to ripen the cervix and induce labor (study group n = 10) or injection of only the diluent (control group n = 10). PGE2 cases showed significant increase in Bishop score and were successfully induced. The mean induction-establishment and induction-delivery intervals were 4.3 +/- 0.1 min and 6.07 +/- 1.7 h, respectively. The control group showed no response. PGE2 cervical injection is a safe and effective method for cervical ripening and labor induction.

Study of serum copper and zinc in cases of hyperemesis gravidarum

The dehydration, electrolyte and metabolic changes which occur in hyperemesis gravidarum are well recognized. The aim of this paper was to study the changes in serum copper and zinc and their correlation with the changes in serum electrolytes that occur in patients with hyperemesis gravidarum. Serum copper, zinc, sodium and potassium and urinary chloride were measured in 30 patients suffering from hyperemesis gravidarum and compared to the levels in 10 normal pregnant women in their first trimester. There was no significant change in serum copper or zinc in patients with hyperemesis compared to normal pregnant women. Also, there was no significant correlation between the changes in the level of these trace elements and the decrease which occurred in serum sodium and potassium and urinary chloride.