Rapid Elimination of the Persistent Synergid through a Cell Fusion Mechanism.

In flowering plants, fertilization-dependent degeneration of the persistent synergid cell ensures one-on-one pairings of male and female gametes. Here, we report that the fusion of the persistent synergid cell and the endosperm selectively inactivates the persistent synergid cell in Arabidopsis thaliana. The synergid-endosperm fusion causes rapid dilution of pre-secreted pollen tube attractant in the persistent synergid cell and selective disorganization of the synergid nucleus during the endosperm proliferation, preventing attractions of excess number of pollen tubes (polytubey). The synergid-endosperm fusion is induced by fertilization of the central cell, while the egg cell fertilization predominantly activates ethylene signaling, an inducer of the synergid nuclear disorganization. Therefore, two female gametes (the egg and the central cell) control independent pathways yet coordinately accomplish the elimination of the persistent synergid cell by double fertilization.

Specialty-Certified Colorectal Surgeons Demonstrate Favorable Short-term Surgical Outcomes for Laparoscopic Low Anterior Resection: Assessment of a Japanese Nationwide Database.

BACKGROUND: There are few studies on the impact of a colorectal-specific technically certified surgeon on good surgical outcomes for laparoscopic low anterior resection in the real world. OBJECTIVE: To evaluate the short-term outcomes of laparoscopic low anterior resection with the participation of a certified colorectal surgeon. DESIGN: This was a retrospective cohort study using a Japanese nationwide database. SETTING: This study was conducted as a project for the Japan Society of Endoscopic Surgery and the Japanese Society of Gastroenterological Surgery. PATIENTS: This study included 41,741 patients listed in the National Clinical Database who underwent laparoscopic low anterior resection performed by certified, noncertified, and colorectal-specific certified surgeons, according to the Endoscopic Surgical Skill Qualification System, from 2016 to 2018. MAIN OUTCOME MEASURES: Operative mortality rate and anastomotic leak rate were the primary outcome measures. RESULTS: Overall 30-day mortality and operative mortality were 0.2% and 0.3%, respectively, without significant differences between all kinds of certified and noncertified surgeon groups. Overall anastomotic leak rate was 9.3%, with a significant difference between the 2 groups. Colorectal- and stomach-certified groups had lower 30-day mortality and operative mortality than the biliary-certified and noncertified groups. The anastomotic leak rate was the lowest in the colorectal-certified group. Based on a logistic regression analysis using the risk-adjusted model, operative mortality was significantly higher in the biliary-certified group than in the colorectal-certified group. Moreover, anastomotic leak rate was significantly lower in the colorectal-certified group than in the stomach-certified and noncertified groups. LIMITATIONS: This study was a retrospective study, and there was a possibility of different definitions of anastomotic leak due to the use of a nationwide database. CONCLUSIONS: The participation of a colorectal-specific certified surgeon may decrease the risk of operative mortality and anastomotic leak for laparoscopic low anterior resection. CIRUJANO COLORRECTAL ALTAMENTE CALIFICADO PROVOCA RESULTADOS QUIRRGICOS FAVORABLES A CORTO PLAZO PARA LA RESECCIN ANTERIOR BAJA LAPAROSCPICA EVALUACIN DE LA BASE DE DATOS NACIONAL JAPONESA: ANTECEDENTES:Hay pocos estudios sobre el impacto de un cirujano certificado técnicamente especializado en cáncer colorrectal con un buen resultado quirúrgico para la resección anterior baja laparoscópica en el mundo real.OBJETIVO:Evaluar los resultados a corto plazo de la resección anterior baja laparoscópica con la participación de un cirujano colorrectal certificado.DISEÑO:Este fue un estudio de cohorte retrospectivo que utilizó una base de datos nacional japonesa.AJUSTE:Este estudio se realizó como un proyecto para la Sociedad Japonesa de Cirugía Endoscópica y la Sociedad Japonesa de Cirugía Gastroenterológica.PACIENTES:este estudio incluyó a 41 741 pacientes incluidos en la base de datos clínica nacional que se sometieron a una resección anterior baja laparoscópica realizada por cirujanos certificados, no certificados y certificados específicamente colorrectales, según el Sistema de calificación de habilidades quirúrgicas endoscópicas de 2016 a 2018.PRINCIPALES MEDIDAS DE RESULTADO:La tasa de mortalidad operatoria y la tasa de fuga anastomótica fueron los resultados primarios.RESULTADOS:La mortalidad general a los 30 días y la mortalidad operatoria fueron del 0,2 % y el 0,3 %, respectivamente, sin diferencias significativas entre los grupos de todos los tipos de cirujanos certificados y no certificados. La tasa global de fuga anastomótica fue del 9,3 %, con una diferencia significativa entre los dos grupos. Los grupos con certificación colorrectal y estomacal tuvieron una mortalidad a los 30 días y una mortalidad operatoria más bajas que los grupos con certificación biliar y sin certificación. La tasa de fuga anastomótica fue la más baja en el grupo certificado colorrectal. Con base en un análisis de regresión logística utilizando el modelo ajustado por riesgo, la mortalidad operatoria fue significativamente más alta en el grupo con certificación biliar que en el grupo con certificación colorrectal. Además, la tasa de fuga anastomótica fue significativamente más baja en el grupo con certificación colorrectal que en los grupos con certificación estomacal y sin certificación.LIMITACIONES:Este estudio fue retrospectivo y existía la posibilidad de diferentes definiciones de fuga anastomótica debido al uso de una base de datos nacional.CONCLUSIONES:La participación de un cirujano certificado en video específico colorrectal puede disminuir el riesgo de mortalidad operatoria y fuga anastomótica para la resección anterior baja laparoscópica. (Traducción-Dr. Mauricio Santamaria ).

Skill-qualified surgeons positively affect short-term outcomes after laparoscopic gastrectomy for gastric cancer: a survey of the National Clinical Database of Japan.

BACKGROUND: Proficiency of the operating surgeon is one of the most critical factors potentially associated with reductions in complications and surgery-related mortality. With video-rating systems having shown potential for assessing laparoscopic surgeons' proficiency, the Endoscopic Surgical Skill Qualification System (ESSQS) was developed by the Japan Society for Endoscopic Surgery to subjectively assess the proficiency of laparoscopic surgeons by rating applicants' non-edited case videos. We conducted a study to evaluate how ESSQS skill-qualified (SQ) surgeon involvement influences short-term outcomes of laparoscopic gastrectomy performed for gastric cancer. METHODS: Data from the National Clinical Database regarding laparoscopic distal and total gastrectomy performed for gastric cancer between January 2016 and December 2018 were analyzed. Operative mortality, defined as 30-day mortality or 90-day in-hospital mortality, and anastomotic leakage rates were compared per involvement vs. non-involvement of an SQ surgeon. Outcomes were also compared per involvement of a gastrectomy-, colectomy-, or cholecystectomy-qualified surgeon. The association between the area of qualification and operative mortality/anastomotic leakage was also analyzed with a generalized estimating equation logistic regression model used to account for patient-level risk factors and institutional differences. RESULTS: Of 104,093 laparoscopic distal gastrectomies, 52,143 were suitable for inclusion in the study; 30,366 (58.2%) were performed by an SQ surgeon. Of 43,978 laparoscopic total gastrectomies, 10,326 were suitable for inclusion; 6501 (63.0%) were performed by an SQ surgeon. Gastrectomy-qualified surgeons outperformed non-SQ surgeons in terms of both operative mortality and anastomotic leakage. They also outperformed cholecystectomy- and colectomy-qualified surgeons in terms of operative mortality or anastomotic leakage in distal and total gastrectomy, respectively. CONCLUSION: The ESSQS appears to discriminate laparoscopic surgeons who can be expected to achieve significantly improved gastrectomy outcomes.

Emergence of artemisinin-resistant Plasmodium falciparum with kelch13 C580Y mutations on the island of New Guinea.

The rapid and aggressive spread of artemisinin-resistant Plasmodium falciparum carrying the C580Y mutation in the kelch13 gene is a growing threat to malaria elimination in Southeast Asia, but there is no evidence of their spread to other regions. We conducted cross-sectional surveys in 2016 and 2017 at two clinics in Wewak, Papua New Guinea (PNG) where we identified three infections caused by C580Y mutants among 239 genotyped clinical samples. One of these mutants exhibited the highest survival rate (6.8%) among all parasites surveyed in ring-stage survival assays (RSA) for artemisinin. Analyses of kelch13 flanking regions, and comparisons of deep sequencing data from 389 clinical samples from PNG, Indonesian Papua and Western Cambodia, suggested an independent origin of the Wewak C580Y mutation, showing that the mutants possess several distinctive genetic features. Identity by descent (IBD) showed that multiple portions of the mutants' genomes share a common origin with parasites found in Indonesian Papua, comprising several mutations within genes previously associated with drug resistance, such as mdr1, ferredoxin, atg18 and pnp. These findings suggest that a P. falciparum lineage circulating on the island of New Guinea has gradually acquired a complex ensemble of variants, including kelch13 C580Y, which have affected the parasites' drug sensitivity. This worrying development reinforces the need for increased surveillance of the evolving parasite populations on the island, to contain the spread of resistance.

Involvement of a skill-qualified surgeon favorably influences outcomes of laparoscopic cholecystectomy performed for acute cholecystitis.

OBJECTIVE: The Endoscopic Surgical Skill Qualification System (ESSQS) was developed by the Japan Society for Endoscopic Surgery as a means of subjectively assessing the proficiency of laparoscopic surgeons. We conducted a study to evaluate how involvement of an ESSQS skill-qualified (SQ) surgeon influences short-term outcomes of laparoscopic cholecystectomy performed for acute cholecystitis. Previous reports suggest that assessment of the video-rating system is a potential tool to discriminate laparoscopic surgeons' proficiency and top-rated surgeons face less surgical mortality and morbidity in bariatric surgery. METHODS: Data from the National Clinical Database regarding laparoscopic cholecystectomy performed for acute cholecystitis between January 2016 and December 2018 were analyzed. Outcomes were compared between patients grouped according to involvement vs. non-involvement of an SQ surgeon. Outcomes were also compared between patients grouped according to whether their operation was performed by biliary tract-, stomach-, or colon-qualified surgeon. RESULTS: Of the 309,998 laparoscopic cholecystectomies during the study period, 65,295 were suitable for inclusion in the study and 13,670 (20.9%) were performed by an SQ surgeon. Patients' clinical characteristics did not differ between groups. Thirty-day mortality was significantly lower in the SQ group (0.1%) 16/13,670 than in the non-SQ group (0.2%) 140/51,625 (P = 0.001). Thirty-day mortality was [0.1% (9/7173)] in the biliary tract-qualified group, [0.2% (5/3527)] in the stomach-qualified group, and [0.1% (2/3240)] in the colon-qualified group. CONCLUSION: Surgeons with ESSQS certification outperform the non-skilled surgeons in terms of surgical mortality in 30 and 90 days. Further verification of the value of the ESSQS is warranted and similar systems may be needed in countries across the world to ensure patient safety and control the quality of surgical treatments.

Activating Nitrogen-doped Graphene Oxygen Reduction Electrocatalysts in Acidic Electrolytes using Hydrophobic Cavities and Proton-conductive Particles.

Although pyridinic-nitrogen (pyri-N) doped graphene is highly active for the oxygen reduction reaction (ORR) of fuel cells in alkaline media, the activity critically decreases under acidic conditions. We report on how to prevent the deactivation based on the mechanistic understanding that O 2 + p y r i - N H + + e - → O 2 , a + p y r i - N H ${{{\rm O}}_{2}+{\rm p}{\rm y}{\rm r}{\rm i}{\rm { -}}{\rm N}{{\rm H}}^{+}+{{\rm e}}^{-}{\to }_{\ }^{{\rm \ }}{{\rm O}}_{2,{\rm a}}+{\rm p}{\rm y}{\rm r}{\rm i}{\rm { -}}{\rm N}{\rm H}}$ governs the ORR kinetics. First, we considered that the deactivation is due to the hydration of pyri-NH+ , leading to a lower shift of the redox potential. Introducing the hydrophobic cavity prevented the hydration of pyri-NH+ but inhibited the proton transport. We then increased proton conductivity in the hydrophobic cavity by introducing SiO2 particles coated with ionic liquid polymer/Nafion® which kept the high onset potentials with an increased current density even in acidic media.

The male gamete membrane protein DMP9/DAU2 is required for double fertilization in flowering plants.

All flowering plants exhibit a unique type of sexual reproduction called 'double fertilization' in which each pollen tube-delivered sperm cell fuses with an egg and a central cell. Proteins that localize to the plasma membrane of gametes regulate one-to-one gamete pairing and fusion between male and female gametes for successful double fertilization. Here, we have identified a membrane protein from Lilium longiflorum generative cells using proteomic analysis and have found that the protein is an ortholog of Arabidopsis DUF679 DOMAIN MEMBRANE PROTEIN 9 (DMP9)/DUO1-ACTIVATED UNKNOWN 2 (DAU2). The flowering plant DMP9 proteins analyzed in this study were predicted to have four transmembrane domains and be specifically expressed in both generative and sperm cells. Knockdown of DMP9 resulted in aborted seeds due to single fertilization of the central cell. Detailed imaging of DMP9-knockdown sperm cells during in vivo and semi-in vitro double fertilization revealed that DMP9 is involved in gamete interaction that leads to correct double fertilization.

Direct splenic vein reconstruction combined with resection of the portal vein/superior mesenteric vein confluence during pancreaticoduodenectomy.

PURPOSE: Splenic vein (SV) ligation combined with portal vein (PV)/superior mesenteric vein (SMV) confluence resection during pancreaticoduodenectomy (PD) is reported to cause left-side portal hypertension (LPH). The purpose of this study was to present our technique of the SV reconstruction and to evaluate the surgical outcomes with/without SV ligation during PD. METHODS: Twenty-four patients undergoing PD with PV and/or SMV resection and being followed over 4 months after surgery between March 2013 and December 2019 in our hospital were evaluated. Resection of the PV/SMV confluence were performed in 14, and SV reconstruction was successfully performed in 3. Presence of LPH was assessed by examining changes in splenic volume, newly venous collateral formation, and platelet counts before and 4-8 months after PD. Surgical technique is the direct anastomosis between SV and PV. RESULTS: Splenic volume ratio was significantly higher in the SV ligation group (n = 11) than in the SV preservation group (n = 13) (median (range) 1.11 (0.57-1.62) vs. 1.68 (1.05-2.22), p < 0.01), but no significant differences were found in the incidence of newly formed venous collaterals or platelet counts between groups. CONCLUSION: SV ligation may represent the cause of LPH after PD combined with resection of PV/SMV confluence. Our simple procedure may help decrease the incidence of LPH.

Parenchymal-sparing approaches for resection of tumors located in the paracaval portion of the caudate lobe of the liver-utility of limited resection and central hepatectomy.

PURPOSE: Resection of liver cancer involving the paracaval portion (PC) of the caudate lobe is challenging because the PC is located deepest in the liver. This study aimed to elucidate the utility of two parenchymal-sparing approaches of limited resection and central hepatectomy for resecting tumors located in the PC. METHODS: In 2018 and 2020, 12 out of 143 patients underwent hepatectomy for tumors located in the PC of the liver. In six patients, limited resection (LR) of the PC after full mobilization of the liver off the inferior vena cava (IVC) was performed for tumors excluding the hilar plate or large hepatic veins (large HVs), including major hepatic veins or thick short hepatic veins. In six patients, central hepatectomy (CH) using liver tunnel was performed for tumors involving or close to the hilar plate and/or large HVs. RESULTS: During CH, the surgical view of the cranial side of the hilar plate was wide enough to perform combined resection of the large HVs in front of the IVC. Five of the six CHs were performed with resection of the LHVs. No LRs were accompanied with resection of the LHVs. The CH was associated with longer Pringle's time (76 min vs. 29.5 min, p = 0.015) and blood loss (1104 ml vs. 370 ml, p = 0.041). The preserved liver parenchyma volumes were 82% and 95% of the total liver volume after CH and LR, respectively. CONCLUSION: Our parenchymal-sparing approach for resection of liver cancer located in the PC is feasible for curative resection.

Recovery and stable persistence of chloroquine sensitivity in Plasmodium falciparum parasites after its discontinued use in Northern Uganda.

BACKGROUND: Usage of chloroquine was discontinued from the treatment of Plasmodium falciparum infection in almost all endemic regions because of global spread of resistant parasites. Since the first report in Malawi, numerous epidemiological studies have demonstrated that the discontinuance led to re-emergence of chloroquine-susceptible P. falciparum, suggesting a possible role in future malaria control. However, most studies were cross-sectional, with few studies looking at the persistence of chloroquine recovery in long term. This study fills the gap by providing, for a period of at least 6 years, proof of persistent re-emergence/stable recovery of susceptible parasite populations using both molecular and phenotypic methods. METHODS: Ex vivo drug-susceptibility assays to chloroquine (n = 319) and lumefantrine (n = 335) were performed from 2013 to 2018 in Gulu, Northern Uganda, where chloroquine had been removed from the official malaria treatment regimen since 2006. Genotyping of pfcrt and pfmdr1 was also performed. RESULTS: Chloroquine resistance (≥ 100 nM) was observed in only 3 (1.3%) samples. Average IC50 values for chloroquine were persistently low throughout the study period (17.4-24.9 nM). Parasites harbouring pfcrt K76 alleles showed significantly lower IC50s to chloroquine than the parasites harbouring K76T alleles (21.4 nM vs. 43.1 nM, p-value = 3.9 × 10-8). Prevalence of K76 alleles gradually increased from 71% in 2013 to 100% in 2018. CONCLUSION: This study found evidence of stable persistence of chloroquine susceptibility with the fixation of pfcrt K76 in Northern Uganda after discontinuation of chloroquine in the region. Accumulation of similar evidence in other endemic areas in Uganda could open channels for possible future re-use of chloroquine as an option for malaria treatment or prevention.

Lack of significant recovery of chloroquine sensitivity in Plasmodium falciparum parasites following discontinuance of chloroquine use in Papua New Guinea.

BACKGROUND: Chloroquine treatment for Plasmodium falciparum has been discontinued in almost all endemic regions due to the spread of resistant isolates. Reversal of chloroquine susceptibility after chloroquine discontinuation has been reported in dozens of endemic regions. However, this phenomenon has been mostly observed in Africa and is not well documented in other malaria endemic regions. To investigate this, an ex vivo study on susceptibility to chloroquine and lumefantrine was conducted during 2016-2018 in Wewak, Papua New Guinea where chloroquine had been removed from the official malaria treatment regimen in 2010. Genotyping of pfcrt and pfmdr1 was also performed. RESULTS: In total, 368 patients were enrolled in this study. Average IC50 values for chloroquine were 106.6, 80.5, and 87.6 nM in 2016, 2017, and 2018, respectively. These values were not significantly changed from those obtained in 2002/2003 (108 nM). The majority of parasites harboured a pfcrt K76T the mutation responsible for chloroquine resistance. However, a significant upward trend was observed in the frequency of the K76 (wild) allele from 2.3% in 2016 to 11.7% in 2018 (P = 0.008; Cochran-Armitage trend test). CONCLUSIONS: Eight years of chloroquine withdrawal has not induced a significant recovery of susceptibility in Papua New Guinea. However, an increasing tendency of parasites harbouring chloroquine-susceptible K76 suggests a possibility of resurgence of chloroquine susceptibility in the future.

Gastric washing by distilled water can reduce free gastric cancer cells exfoliated into the stomach lumen.

PURPOSE: Intragastric free cancer cells in patients with gastric cancer have rarely been studied. The purpose of this study was to investigate the detection rate of intragastric free cancer cells in gastric washes using two types of solutions during endoscopic examination. We further clarified risk factors affecting the presence of exfoliated free cancer cells. METHODS: A total of 175 patients with gastric cancer were enrolled. Lactated Ringer's solution (N = 89) or distilled water (DW; N = 86) via endoscopic working channel was sprayed onto the tumor surface, and the resultant fluid was collected for cytological examination. We compared the cancer-cell positivity rate between the two (Ringer and DW) groups. We also tested the correlation between cancer-cell positivity and clinicopathological factors in the Ringer group to identify risk factors for the presence of exfoliated cancer cells. RESULTS: The cancer-cell positivity rate was significantly higher in the Ringer group than that in the DW group (58 vs 6%). Cytomorphology in the Ringer group was well maintained, but not in the DW group. The larger tumor size (≥ 20 mm) and positive lymphatic involvement were significant risk factors of exfoliated free cancer cells. CONCLUSIONS: Cancer cells can be highly exfoliated from the tumor surface into the gastric lumen by endoscopic irrigation in large gastric cancer with lymphatic involvement. Gastric washing by DW can lead to cytoclasis of free cancer cells; therefore, it may minimize the possibility of cancer-cell seeding in procedures carrying potential risks of tumor-cell seeding upon transluminal communication, such as endoscopic full-thickness resection and laparoscopy-endoscopy cooperative surgery.

Establishment of pathological quantitative method for determining undifferentiated component ratio in patients with differentiated/undifferentiated mixed-type early gastric cancer and clinical significance of this ratio.

PURPOSES: The purpose of this study was to establish a pathological quantitative method for determining the undifferentiated components ratio (UCR) in patients with differentiated/undifferentiated mixed-type (Mixed-type) early gastric cancer (EGC) and to examine the clinical significance. METHODS: The subjects were 410 patients who underwent surgical resection for EGC with the invasion limited to m or sm1. Analysis 1: In 12 randomly selected patients with Mixed-type cancer, we calculated the area ratio and the ratio of the length ratio using ImageJ and analyzed the correlation between them. Analysis 2: We generated ROC curves, and determined the cutoff UCR on the basis of the predictive risk factors for lymph node metastasis (LNM). Analysis 3: We analyzed the relationship between clinicopathological factors including UCR/length of undifferentiated component (LUC = maximum dimensions of tumor × UCR) and LNM. RESULTS: Analysis 1: The length ratio can be used as a substitute parameter for the UCR (r = 0.996). Analysis 2: The cutoff UCR as a risk factor for LNM was 58% (sensitivity = 1, 1 - specificity = 0.404). Analysis 3: Lymphovascular invasion (p < 0.0001), UCR ≥58% (p = 0.023), and LUC ≥25 mm (p = 0.005) were identified as significant risk factors for LNM. No LNM was observed in patients with invasion limited to m or sm1 and negativity for lymphovascular invasion and UCR <58% (0/215). CONCLUSIONS: In the patients with Mixed-type EGC, the length ratio of undifferentiated components can be a substitute parameter for the UCR. LNM rarely occurs in patients without lymphovascular invasion and with an UCR <58%. The analysis of the UCR has great significance in determining whether additional surgical resection is required after endoscopic resection.

Comparison between endoscopic and laparoscopic removal of gastric submucosal tumor.

BACKGROUND AND AIM: A retrospective study was conducted to compare two resection methods, namely, endoscopic resection (ER) procedures (endoscopic submucosal dissection [ESD], endoscopic muscularis dissection [EMD], and endoscopic full-thickness resection [EFTR]) and laparoscopic resections (LR) (laparoscopic endoscopic cooperative surgery [LECS] and laparoscopic wedge resection). METHODS: Seventy-three patients who underwent ER (N = 33: ESD, N = 4; EMD, N = 15; EFTR, N = 14) or LR (N = 39: LECS, N = 16; wedge resection, N = 23) for gastric submucosal tumor (G-SMT) smaller than 50 mm were included in this study. Patient/tumor characteristics and intra/postoperative factors were compared between the ER and LR groups. RESULTS: The ER group had a significantly higher percentage of intraluminal growing type of tumor (100% vs 41%) and smaller tumor size (23 vs 33 mm) than the LR group. The ER group had a significantly shorter operative time (93 vs 145 min) and less blood loss (13 vs 30 mL) than the LR group. In the ER group, three patients who had tumors located on the anterior wall of the stomach required laparoscopic closure after EFTR because of difficulty in endoscopic closure of the gastric-wall defect. Postoperative complication rates and duration of postoperative hospital stays did not differ between the two groups. CONCLUSIONS: ER may be technically feasible, safe, less invasive, and oncologically appropriate options for selected patients with the intraluminal growing type of G-SMT smaller than 30 mm. EFTR may be more reasonable alternatives to LR in selected patients with a small G-SMT located on the lesser curvature side.

Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.

Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes.

Effect of Carbon Supports on Enhancing Mass Kinetic Current Density of Fe-N/C Electrocatalysts.

The mass kinetic current density (mass JK ) of most extensively reported M-N/C catalysts (M represents non-precious metal elements such as Fe, Co, and Cu), a potential alternative to noble metal catalysts in fuel cells, is poorer than that of commercial Pt/C. Thus, deep understanding of the intrinsic roles of carbon supports may contribute to the development of M-N/C catalysts from a practical point of view. Herein, the routinely used carbon supports, i.e. carbon black (CB) and carbon nanotubes (CNT) that have different morphology and crystallinity, were investigated to uncover the factors that affected the mass JK of Fe-N/C in electrocatalytic oxygen reduction. When immobilized on CB, the ionic liquids-derived Fe-N/C exhibited an enhanced mass JK (4.45 A g-1 at 0.80 V vs. RHE) by a factor of 2.14 times, comparable to that of Pt/C (5.79 A g-1 ) and higher than most reported M-N/C catalysts to our best knowledge. In contrast, the CNT support system showed no improvement. It was revealed that a compatible interface between the Fe-N/C precursors and the carbon supports was vital to ensure in-situ growth of a uniform catalyst layer on the supports during pyrolysis. This subsequently promotes the mass JK by exposing more embedded active sites and introducing favorable slit pores for effective mass-diffusion. This work would be promising to address the long-term overlooked challenge of the low mass JK of M-N/C catalysts in replacing noble-metal catalysts for practical fuel cell applications.

Exosomes versus microexosomes: Shared components but distinct functions.

In multicellular organisms, cellular components are constantly translocated within cells and are also transported exclusively between limited cells, regardless of their physical distance. Exosomes function as one of the key mediators of intercellular transportation. External vesicles were identified 50 years ago in plants and now reconsidered to be exosome-like vesicles. Meanwhile, a well-known exosomal component, tetraspanin CD9, regulates sperm-egg fusion in mammals. A number of Arabidopsis tetraspanins are also expressed in reproductive tissues at fertilization, and are localized at the plasma membrane of protoplasts. Moreover, CD9-containing structures (or 'microexosomes') are released from mouse eggs during their maturation and promote the sperm-egg fusion. This phenomenon implies that two types of shared-component intercellular carriers might be released from multiple types of plant and animal cells, which widely regulate biological phenomena. We herein highlight their discrete structures, formation processes, and functions.

Highly Ordered Nitrogen-Rich Mesoporous Carbon Nitrides and Their Superior Performance for Sensing and Photocatalytic Hydrogen Generation.

Mesoporous carbon nitrides (MCN) are fascinating materials with unique semiconducting and basic properties that are useful in many applications including photocatalysis and sensing. Most syntheses of MCN focus on creating theoretically predicted C3 N4 stoichiometry with a band gap of 2.7 eV using a nano-hard templating approach with triazine-based precursors. However, the performance of the MCN in semiconducting applications is limited to the MCN framework with a small band gap, which would be linked with the addition of more N in the CN framework, but this remains a huge challenge. Here, we report a precursor with high nitrogen content, 3-amino-1,2,4-triazole, that enables the formation of new and well-ordered 3D MCN with C3 N5 stoichiometry (MCN-8), which has not been predicted so far, and a low-band-gap energy (2.2 eV). This novel class of material without addition of any dopants shows not only a superior photocatalytic water-splitting performance with a total of 801 µmol of H2 under visible-light irradiation for 3 h but also excellent sensing properties for toxic acids.

Sex-specific posttranslational regulation of the gamete fusogen GCS1 in the isogamous volvocine alga Gonium pectorale.

Male and female, generally defined based on differences in gamete size and motility, likely have multiple independent origins, appearing to have evolved from isogamous organisms in various eukaryotic lineages. Recent studies of the gamete fusogen GCS1/HAP2 indicate that this protein is deeply conserved across eukaryotes, and its exclusive and/or functional expression generally resides in males or in male homologues. However, little is known regarding the conserved or primitive molecular traits of males and females within eukaryotes. Here, using morphologically indistinguishable isogametes of the colonial volvocine Gonium pectorale, we demonstrated that GCS1 is differently regulated between the sexes. G. pectorale GCS1 molecules in one sex (homologous to male) are transported from the gamete cytoplasm to the protruded fusion site, whereas those of the other sex (females) are quickly degraded within the cytoplasm upon gamete activation. This molecular trait difference might be conserved across various eukaryotic lineages and may represent male and female prototypes originating from a common eukaryotic ancestor.