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Certain soil insects, such as the root-damaging larvae of the maize pest Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), are increasingly difficult to control because of recent bans of some insecticides. An alternative and safer approach may be the development of biopesticides based on entomotoxic defense proteins of higher fungi. Many of these potentially interesting proteins are protease inhibitors, and some have been shown to adversely affect insects. We examined the effects of the cysteine protease inhibitors macrocypin 1, 3, and 4 from Macrolepiota procera, clitocypin from Clitocybe nebularis, and cocaprin 1 and the serine protease inhibitor cospin 1 from Coprinopsis cinerea on D. v. virgifera. We confirmed the inhibition by mycocypins of the cysteine catalytic-type proteolytic activities in gut extracts of larvae and adults. The inhibition of pGlu-Phe-Leu-hydrolyzing activity was stronger than that of Z-Phe-Arg-hydrolyzing activity. Mycocypins and cospin resisted long-term proteolytic digestion, whereas cocaprin 1 was digested. Bioassays with overlaid artificial diet revealed no effects of proteins on neonatal mortality or stunting, and no effects on adult mortality. Immersion of eggs in protein solutions had little effect on egg hatching or mortality of hatching neonates. Microscopic analysis of the peritrophic matrix and apical surface of the midguts revealed the similarity between larvae of D. v. virgifera and the chrysomelid Leptinotarsa decemlineata, which are sensitive to these inhibitors. The resistance of D. v. virgifera to fungal protease inhibitors is likely due to effective adaptation of digestive enzyme expression to dietary protease inhibitors. We continue to study unique protein complexes of higher fungi for the development of new approaches to pest control.
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We report on an optical architecture delivering sub-120 femtosecond laser pulses of 20 µJ tunable from 5.5 µm to 13 µm in the mid-infrared range (mid-IR). The system is based on a dual-band frequency domain optical parametric amplifier (FOPA) optically pumped by a Ti:Sapphire laser and amplifying 2 synchronized femtosecond pulses each with a widely tunable wavelength around 1.6 and 1.9 µm respectively. These amplified pulses are then combined in a GaSe crystal to produce the mid-IR few-cycle pulses by means of difference frequency generation (DFG). The architecture provides a passively stabilized carrier-envelope phase (CEP) whose fluctuations has been characterized to 370â mrad RMS.
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The western corn rootworm (WCR) Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains of Bacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from several Chryseobacterium species. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms.
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Bacillus thuringiensis , Chryseobacterium , Escarabajos , Plaguicidas , Animales , Zea mays/genética , Chryseobacterium/metabolismo , Plaguicidas/farmacología , Endotoxinas/metabolismo , Proteínas Bacterianas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Escarabajos/genética , Larva/metabolismo , Bacillus thuringiensis/genética , Control Biológico de Vectores , Resistencia a los InsecticidasRESUMEN
Post-compression of 12-fs laser pulses with multi-TW peak power from an optical parametric chirped pulse amplification (OPCPA) system was performed by using a single thin fused silica plate in a vacuum. By optimizing the input pulses in both spatial and temporal domains, after compression with customized chirped mirrors, we achieved pulses as short as 3.87 fs, in combination with 12-mJ energy. The spatio-spectral quality of the post-compressed pulses was thoroughly analyzed. The generated 1.4-cycle pulses pave the way for next generation attosecond and particle acceleration experiments.
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Background: Organization of mass sport events in the COVID-19 era is utterly complicated. Containments measures, required to avoid a virus outbreak, force athletes to compete under circumstances they never experienced before, most likely having a deleterious effect on their performance. Purpose: We aimed to design a so-called athlete-friendly bubble system for the International Swimming League 2020 event, which is strict enough to avoid a COVID-19 outbreak, but still provides a supportive environment for the athletes. Methods: To avoid the feeling of imprisonment, athletes were permitted to spend a certain amount of time in the parks surrounding the hotels. Such alleviations were possible to apply with strict adherence to the hygienic and social distancing protocols and regular COVID-19 testing. Evaluation of every COVID-19 positive case was key, and if prolonged PCR positivity or false positive PCR result was identified, the unnecessary quarantine was planned to be lifted. Return to play protocol (RTP) was planned, in case of a COVID-19 infection of an athlete inside the bubble. To test, if the athlete-friendly system provided a supportive environment, we evaluated athlete performance. Results: 11,480 PCR tests were performed for 1,421 individuals. 63 COVID-19 positive cases were detected, of which 5 turned out to be clinically insignificant, either because of prolonged PCR positivity or because of a false positive result. 93.1% of the positive cases were detected in the local crew, while no athlete got infected inside the bubble, as the two infected athletes were tested positive upon arrival. RTP was provided for two athletes. 85% of the athletes showed improvement during the bubble and 8 world records were broken. Conclusion: The applied protocol proved to be effective, as no athlete got infected inside the bubble, moreover, the athlete-friendly system supported the athletes to improve their performance.
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Rendimiento Atlético , COVID-19 , Humanos , Natación , Prueba de COVID-19 , COVID-19/diagnóstico , COVID-19/epidemiología , AtletasRESUMEN
The calibration of an ion detection system was carried out for protons and carbon ions from a few tens of keV up to about 1 MeV energies. A Thomson spectrometer deflecting the particle beam accelerated from a laser plasma creates the ion spectra on a phosphor screen behind a micro-channel plate (MCP), which are recorded by a camera. During calibration, the ion spectra simultaneously hit the slotted CR-39 track detector installed in front of the MCP and, passing through the adjacent CR-39 stripes, the MCP. The calibration provides the ratio of the interpolated values between two consecutive stripes of the camera signal and the total number of particles recorded on the corresponding stripe of CR-39. The efficiency of proton detection by CR-39 was also measured in a conventional accelerator beam and found to drop by 20% below 100 keV.
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Introduction: During liver transplantation, haemostasis is typically assessed by means of standard laboratory tests and viscoelastic tests, while dynamic monitoring of coagulation factor specific blood losses is an unusual, yet established approach. Aim: Our aim was to evaluate the volume-based haemostasis reserves in blood product free liver transplants in the first perioperative 48 hours, in association with the Child-Pugh score. Method: Data of 59 blood product free liver transplanted patients' coagulation factor levels, viscoelastic parameters and coagulation factor specific blood losses according to Gross methodological, baseline and 'coagulopathic' trigger levels were analysed. The haemostasis reserves were estimated according to the Child-Pugh classification. Laboratory tests and the calculation of haemostasis reserves were carried out before liver transplantation (T1), at the end of the surgery (T2) and also 12-24-48 hours postoperatively (T3-T4-T5). The viscoelastic tests were performed before liver transplantation (T1) and at the end of the surgery (T2). Results: Fibrinogen levels decreased by 1.2 g/L. Factor II, V, VII, X levels decreased by 26-40%. From T2 to T4, fibrinogen increased by 0.9 ± 0.6 g/L over 24 h (p<0.001). Factor II, V, VII, X levels increased by 12-30% between T3 to T5 (p<0.001). The viscoelastic parameters remained in the normal range during liver transplantation (T1-T2). Haemostasis reserves decreased by 61% at the end of surgery (p<0.001), but reached 88% of the preoperative value on the second postoperative day. The initial reserves of Child B and C groups were 36-41% lower than Child A, nevertheless, these differences were not significant at 48 hours. Conclusion: The volume-based haemostasis approach supplements the standard laboratory and viscoelastic tests. This unusual approach dynamically indicates the actual reserve of haemostasis and shows the 'weakest link' within the system. Orv Hetil. 2020; 161(7): 252-262.
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Hemostasis , Trasplante de Hígado , Pruebas de Coagulación Sanguínea , Fibrinógeno/metabolismo , HumanosRESUMEN
In the last decades, the results of liver transplantation have shown significant improvement. More patients are eligible for liver transplantation, while the indications are changing. The worldwide shortage of donor organs urges the profession for the development of new strategies. With rational extension of donor criteria, more precise organ allocation, personalized donation, living related donation, machine perfusion, and donation after cardiac death, liver transplantation is becoming available for more and more patients suffering from end stage liver disease. Hereby we summarize the new possibilities and challenges in the light of the Hungarian liver transplant program. Orv Hetil. 2019; 160(29): 1127-1135.
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Trasplante de Hígado , Perfusión , Donantes de Tejidos , Obtención de Tejidos y Órganos/tendencias , Muerte , Selección de Donante , Humanos , Hungría , Neoplasias Hepáticas/cirugía , Trasplante de Hígado/tendencias , Perfusión/métodos , Perfusión/tendencias , Obtención de Tejidos y Órganos/estadística & datos numéricosRESUMEN
This paper presents a single-shot technique for measuring CEP. The Temporal dispersion based One-shot Ultrafast Carrier envelope phase Analysis method (TOUCAN) is an arbitrary repetition rate single-shot CEP drift measurement technique based on dispersive Fourier transformations and has been experimentally tested at 100 kHz. TOUCAN was validated by a direct comparison of decimated data with an independent traditional CEP drift measurement technique. The impact of a temporal jitter on the CEP drift measurement is investigated and a new mitigation technique is shown to produce high accuracy jitter-free CEP drift extraction.
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Machine perfusion of marginal grafts might be a possible solution to organ shortage and a promising tool for reducing waiting list morbidity and mortality. In recent years, optimizing the circumstances of organ preservation prior to implantation via machine perfusion has become a hot topic of research. Machine perfusion offers a platform for organ reconditioning, assessment of cell viability and function, pharmacological preconditioning, prolongation of preservation time (ischemia time) and finally reducing graft injury. The objective of the new technology is to increase the pool of transplantable organs safely. Multicentric prospective studies have been evaluating the short and long term outcomes of different methods, however, several questions still remain unanswered. This review summarizes the recent advances in the field of machine perfusion, focusing on preclinical and clinical results. Machine perfusion seems to be a new milestone in the modern era of solid organ transplantation. Orv Hetil. 2018; 159(46): 1882-1890.
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Trasplante de Órganos/métodos , Trasplante de Órganos/tendencias , Perfusión/métodos , Perfusión/tendencias , Trasplante de Corazón/métodos , Trasplante de Corazón/tendencias , Humanos , Trasplante de Riñón/métodos , Trasplante de Riñón/tendencias , Trasplante de Hígado/métodos , Trasplante de Hígado/tendencias , Trasplante de Pulmón/métodos , Trasplante de Pulmón/tendencias , Preservación de Órganos , Trasplante de Páncreas/métodos , Trasplante de Páncreas/tendenciasRESUMEN
The scheme of cascaded extraction optical parametric amplifier (CE-OPA) has been proposed as a final amplifier for high peak power laser systems. 4D numerical simulations show that conversion efficiency of a CE-OPA system pumped with a temporal Gaussian pump pulse is as close to the theoretical limit of quantum efficiency as a conventional OPA pumped with temporal flat-top pump pulse. The CE-OPA system is also similar to the conventional scheme in output energy stability and alignment sensitivity of the phase-matching angles, too. However, with the use of the CE-OPA scheme, the requirement of pump pulse shaping can be relaxed, leading to an overall higher plug in efficiency as well as compact design.
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Besides orthotopic liver transplantation (OLT) there is no long-term and effective replacement therapy for severe liver failure. Artificial extracorporeal liver supply devices are able to reduce blood toxin levels, but do not replace any synthetic function of the liver. Molecular adsorbent recirculating system (MARS) is one of the methods that can be used to treat fulminant acute liver failure (ALF) or acute on chronic liver failure (AoCLF). The primary non-function (PNF) of the newly transplanted liver manifests in the clinical settings exactly like acute liver failure. MARS treatment can reduce the severity of complications by eliminating blood toxins, so that it can help hepatic encephalopathy (HE), hepatorenal syndrome (HRS), and the high rate mortality of cerebral herniation. This might serve as a bridging therapy before orthotopic liver retransplantation (reOLT). Three patients after a first liver transplantation became candidate for urgent MARS treatment as a bridging solution prior to reOLT in our center. Authors report these three cases, fo-cusing on indications, MARS sessions, clinical courses, and final outcomes.
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UNLABELLED: Liver transplantation is a routinely used therapeutic choice in the treatment of end stage liver disease. Portal vein stenosis is a rare vascular complication after liver transplantation. We report the interventional radiological management of three cases of portal vein stenosis. AIM: The surgical management of portal vein stenosis can be hazardous for the patient and the transplanted liver in the early post-transplantation period. In general, interventional radiological methods are tolerable for patients and can be safely performed with high success rate. The aim of this report is to analyze the feasibility, the risks and the efficacy of the percutaneous transhepatic self expanding metallic stent placement into the portal vein. METHOD: Three of the 396 liver transplantations cases in Budapest developed significant portal vein stenosis. In these cases, ultrasound guided percutaneous transhepatic portal vein puncture with fine needle was performed. The tract was dilated with a coaxial dilator set, and an adequately sized sheath introducer was inserted into the liver parenchyma. Two nitinol and one stainless steel self expanding metallic stent were implanted at the stenotic portal vein anastomoses. The tract was embolized with gelfoam particles (1 case), or coils (1 case). In the third patient no tract embolization was performed. RESULT: All treatments were technically successful, without minor or major complications. In two cases the amount of free abdominal fluid decreased significantly, and in the third case the esophageal varicosity regressed. The morphological success was documented with ultrasound and computed tomography examination. Two patients are alive and well after 10 and 39 months of follow up, while the third patient died after one month in multi organ failure. CONCLUSION: Percutaneous transhepatic metallic stent placement for the treatment of post-transplantation portal vein stenosis is a safe and effective method.
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Trasplante de Hígado/efectos adversos , Vena Porta/patología , Vena Porta/cirugía , Stents , Adulto , Anastomosis Quirúrgica , Constricción Patológica/etiología , Constricción Patológica/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Ultrasonografía Doppler en Color , Ultrasonografía Doppler de Pulso , Grado de Desobstrucción VascularRESUMEN
Because of the long waiting time for pediatric liver transplantation, new techniques of liver transplantation were invented. Split and living-donor related liver transplantation are common today and the Kaplan-Meier (3 years) overall survival is over 80%. By splitting the liver, two recipients can be transplanted. In general, the left lobe is used for the pediatric, the right lobe for the adult recipient. There are a lot of combinations depending on the donor and recipient weight. The accepted liver volume is approx. 1% of the recipient body weight. The results of the Hungarian pediatric program improve, 27 transplantations were done using 14 partial liver grafts and living donor program was started. Using strict protocols and improving surgical skills, the overall pediatric survival was over 80% in the last 5 years.
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Trasplante de Hígado/métodos , Donadores Vivos , Adolescente , Adulto , Niño , Protocolos Clínicos , Humanos , Hungría/epidemiología , Estimación de Kaplan-Meier , Trasplante de Hígado/mortalidadRESUMEN
INTRODUCTION: The authors summarize the characteristics of biliary complications following liver transplantation in the Hungarian liver transplant program. Aims were to analyze the frequency and the types of biliary complications as well as their effect on the patient and graft survival. The authors observed the known risk factors in the Hungarian practice, and they also try to find unknown risk factors for biliary complications. They review the therapy of biliary complications. METHOD: In the retrospective study, patients were divided into two groups, with and without biliary complication after liver transplantation. These two groups were compared with many factors, and with the survivals. The biliary complication group was divided into two parts: those who had an early and those with a late biliary complication. These two new groups were also compared with the controls. The results are summarized in tables and statistical figures. Categorical variables are evaluated by chi 2 -test, continuous ones are with Levine Test (for homogenicity of means), Student T test and Mann-Whitney U-test. Cumulative survivals are computed with Kaplan-Meier log rank analysis. RESULTS: Biliary complication appeared in 25% of the patients. The most frequent complications were stenosis (18%), biliary leakage (9%), biliary necrosis (6%), and ischaemic type of biliary lesions (3%). The 5-year survival is worse when biliary complications were diagnosed (55%) than without such a complication (66%). In the biliary complication group the retransplantation rate was higher (15%). The most frequent treatments were interventional radiologic methods (69%), surgical methods (17%), and the ERCP. CONCLUSIONS: The rate of biliary complications met the international reviews. Risk factors for biliary complications were cholangitis, hepatic artery thrombosis and stenosis, high rate of intraoperative blood transfusions, and acute rejection. Biliary complications frequently associated with the initial poor function of the transplanted graft. Early biliary complications have a negative impact on patient survival, while late complications influence a decreased quality of life. Biliary complications were treated mostly by interventional radiologic procedures.
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Bilis , Enfermedades de las Vías Biliares/etiología , Sistema Biliar/patología , Trasplante de Hígado/efectos adversos , Adulto , Anciano , Atresia Biliar/etiología , Sistema Biliar/fisiopatología , Enfermedades de las Vías Biliares/diagnóstico por imagen , Enfermedades de las Vías Biliares/patología , Enfermedades de las Vías Biliares/fisiopatología , Colestasis/etiología , Constricción Patológica/etiología , Femenino , Humanos , Hungría , Isquemia/etiología , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Necrosis/etiología , Calidad de Vida , Radiografía Intervencional , Estudios Retrospectivos , Factores de Riesgo , Factores de TiempoRESUMEN
UNLABELLED: Liver resection is the curative therapeutic option for hepatocellular carcinoma, biliary tumors, metastases of colorectal and other extrahepatic tumors, living donor liver transplantation and other benign liver diseases. AIM OF STUDY: To summarize the evaluation methods of liver function before living donor liver transplantation and liver resection. METHOD: We summarize the literature about the evaluation of liver function. RESULTS: Perioperative mortality is determined mostly by the extent of preoperative evaluation focused on the liver. After resection the remnant liver parenchyma must cope with the challenge caused by increased metabolism, portal overflow, decreased vascular bed and biliary tract and oxidative stress following the operation. If the remnant liver is unable to grow up to this challenge, acute liver failure occurs. This maintains the necessity of determining the hepatic functional reserve and the hepatic remnant volume. Child-Pugh classification is widely spread to predict outcome. Dynamic functional tests such as indocyanine green retention test, galactosyl human serum albumin scintigraphy and aminopyrine breath tests can be used to evaluate hepatic reserve. To determine remnant liver volume modern imaging processes such as CT volumetry and hepatobiliary scintigraphy are available. CONCLUSION: After the detailed evaluation resection can be limited to an extent which is oncologically radical enough (1% remnant liver tissue/kg) and spares parenchyma which can ensure survival yet. With careful preoperative examination mortality can be reduced even to reach zero.
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Hepatectomía/efectos adversos , Fallo Hepático Agudo/etiología , Fallo Hepático Agudo/metabolismo , Pruebas de Función Hepática , Trasplante de Hígado , Hígado/metabolismo , Donadores Vivos , Aminopirina/metabolismo , Sistema Biliar/diagnóstico por imagen , Pruebas Respiratorias/métodos , Carcinoma Hepatocelular/cirugía , Colangiocarcinoma/cirugía , Galactosa/metabolismo , Humanos , Verde de Indocianina , Hígado/diagnóstico por imagen , Hígado/fisiopatología , Hígado/cirugía , Circulación Hepática , Fallo Hepático Agudo/diagnóstico por imagen , Fallo Hepático Agudo/fisiopatología , Neoplasias Hepáticas/cirugía , Estrés Oxidativo , Sistema Porta , Valor Predictivo de las Pruebas , Cintigrafía , Albúmina Sérica/metabolismo , Tomografía Computarizada por Rayos XRESUMEN
The living related donor mortality after liver donation could occur as a result of postoperative cardiovascular and thromboembolic complication; which could be minimized by detailed preoperative assessment of the living donor. The preoperative functional tests evaluate the physiological reserve or identify the living donors with limited response to the surgical stress. Based on the results of CT volumetry, MRI and liver functional reserve capacity test (indocyanine green retention ratio) the liver resection can be done safely. The preoperative cytochrome P enzymes tests of donors identify the drugs with abnormal metabolism. Balanced anesthesia combined with thoracic epidural anesthesia is done with liver safe, renal safe and ischemic preconditioning drugs. Normovolemic state is maintained with physiologic extrahepatic perfusion and oxygenation conditions. The central venous and hepatic artery pressure is reduced with the guarantee of optimal hepatic perfusion-oxygenation and better liver resection condition. Intraoperative thrombosis prophylaxis is performed with sequential compression device. After liver resection the donor morbidity can be reduced, effective analgesia, thrombosis prophylaxis, liver safe drug therapy and a tight monitoring. Before the first postoperative mobilization a deep vein Doppler ultrasound control is proposed.
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Anestesia General/métodos , Cuidados Críticos , Hepatectomía/efectos adversos , Hepatectomía/métodos , Trasplante de Hígado , Donadores Vivos , Analgésicos/administración & dosificación , Anestesia Epidural/métodos , Cuidados Críticos/métodos , Sistema Enzimático del Citocromo P-450/metabolismo , Humanos , Hígado/enzimología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Trombosis/etiología , Trombosis/prevención & controlRESUMEN
It is generally assumed that the developmental program of embryogenesis relies on epigenetic mechanisms. However, a mechanistic link between epigenetic marks and cell fate decisions had not been established so far. In a recent article, Torres-Padilla and colleagues show that epigenetic information and, more precisely, histone arginine methylation mediated by CARM1 could contribute to cell fate decisions in the mouse 4-cell-stage embryo. It provides the first indications that global epigenetic information influences allocation of pluripotent cells toward the first cell lineages.
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The Ca2+ oscillations initiated by the fertilizing sperm (but terminating concomitant with pronucleus formation) apparently ensure that the events constituting egg activation occur in the correct temporal order; early events (e.g., cortical granule exocytosis) require fewer oscillations than later events (e.g., recruitment of maternal mRNA). Whether the Ca2+ signaling events impact long-term development, in particular development to term, is unknown. Using fertilized eggs that have undergone the first few Ca2+ oscillations, we developed procedures that result either in inhibiting or stimulating the natural pattern of Ca2+ signaling of inseminated eggs. Although the incidence of development to the blastocyst stage is unaltered by these procedures, fewer offspring are born following embryo transfer, indicating that developmental competence of the blastocysts is reduced. Interestingly, embryo transfer experiments reveal that when the natural regime of Ca2+ oscillations is precociously interrupted, the incidence of implantation is compromised whereas hyper-stimulation of Ca2+ signaling events compromises post-implantation development. Moreover, although there was no major difference in the overall growth rates of the offspring, those obtained following hyper-stimulation exhibited a far greater variability in their weight. Analysis of global patterns of gene expression by microarray analysis revealed that approximately 20% of the transcripts are mis-regulated when too few oscillations are experienced by the embryo and EASE analysis indicates that genes preferentially involved in RNA processing and polymerase II transcription are differentially affected. In addition, a set of genes involved in cell adhesion is also mis-expressed and could thus be mechanistically linked to the observed reduced implantation. Only about 3% of the transcripts were mis-regulated following hyper-stimulation, and EASE analysis indicates that genes preferentially involved in metabolism are differentially affected. In toto, these results indicate that a range Ca2+ signaling events following fertilization (an excess or reduction) has long-term effects on both gene expression and development to term.
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Calcio/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Resultado del Embarazo , Cigoto/metabolismo , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Embarazo , Resultado del Embarazo/veterinariaRESUMEN
Egg activation in mammals is caused by cytosolic Ca(2+) oscillations that are essential for development. However, despite increasing knowledge about signal transduction mechanisms, the functional linkage between frequency number, amplitude and duration of the Ca(2+) signal and the kinetics of pronucleus formation has not yet been defined. While a wide range of Ca(2+) signal parameters are efficient in causing egg activation, the basic rules governing how the egg integrates these signalling events are not yet clear. Thus, in the perspective of better understanding how the egg processes Ca(2+) signalling events, the objective of this study was to determine experimentally whether the efficiency of egg activation and the subsequent early developmental stages rely on Ca(2+) signalling summation. Non-fertilized, but freshly ovulated mouse eggs, were subjected to a series of repetitive Ca(2+) influxes of various patterns modulated by a non-invasive membrane electropermeabilization method. Using a combination of two suboptimal treatments we have shown that mouse eggs can sum up the effects caused by various patterns of intracellular Ca(2+) concentrations transient during the period of egg activation. In addition, overloading the intracellular milieu by repetitive Ca(2+) influxes did not seem to inhibit the process of activation. The kinetics of pronuclear formation among a population of eggs treated in the same conditions became accelerated when the total dose of Ca(2+) signal 'experienced' by the eggs was increased. The results suggested that summation of the biological effects of all Ca(2+) signals constitutes an important mode of Ca(2+) signal integration.