Recognition of Microbe- and Damage-Associated Molecular Patterns by Leucine-Rich Repeat Pattern Recognition Receptor Kinases Confers Salt Tolerance in Plants.

In plants, a first layer of inducible immunity is conferred by pattern recognition receptors (PRRs) that bind microbe- and damage-associated molecular patterns to activate pattern-triggered immunity (PTI). PTI is strengthened or followed by another potent form of immunity when intracellular receptors recognize pathogen effectors, termed effector-triggered immunity. Immunity signaling regulators have been reported to influence abiotic stress responses as well, yet the governing principles and mechanisms remain ambiguous. Here, we report that PRRs of a leucine-rich repeat ectodomain also confer salt tolerance in Arabidopsis thaliana, following recognition of cognate ligands such as bacterial flagellin (flg22 epitope) and elongation factor Tu (elf18 epitope), and the endogenous Pep peptides. Pattern-triggered salt tolerance (PTST) requires authentic PTI signaling components; namely, the PRR-associated kinases BAK1 and BIK1 and the NADPH oxidase RBOHD. Exposure to salt stress induces the release of Pep precursors, pointing to the involvement of the endogenous immunogenic peptides in developing plant tolerance to high salinity. Transcriptome profiling reveals an inventory of PTST target genes, which increase or acquire salt responsiveness following a preexposure to immunogenic patterns. In good accordance, plants challenged with nonpathogenic bacteria also acquired salt tolerance in a manner dependent on PRRs. Our findings provide insight into signaling plasticity underlying biotic or abiotic stress cross-tolerance in plants conferred by PRRs.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Promotion and Upregulation of a Plasma Membrane Proton-ATPase Strategy: Principles and Applications.

Plasma membrane proton-ATPase (PM H+-ATPase) is a primary H+ transporter that consumes ATP in vivo and is a limiting factor in the blue light-induced stomatal opening signaling pathway. It was recently reported that manipulation of PM H+-ATPase in stomatal guard cells and other tissues greatly improved leaf photosynthesis and plant growth. In this report, we review and discuss the function of PM H+-ATPase in the context of the promotion and upregulation H+-ATPase strategy, including associated principles pertaining to enhanced stomatal opening, environmental plasticity, and potential applications in crops and nanotechnology. We highlight the great potential of the promotion and upregulation H+-ATPase strategy, and explain why it may be applied in many crops in the future.

Danger peptide receptor signaling in plants ensures basal immunity upon pathogen-induced depletion of BAK1.

Pathogens infect a host by suppressing defense responses induced upon recognition of microbe-associated molecular patterns (MAMPs). Despite this suppression, MAMP receptors mediate basal resistance to limit host susceptibility, via a process that is poorly understood. The Arabidopsis leucine-rich repeat (LRR) receptor kinase BAK1 associates and functions with different cell surface LRR receptors for a wide range of ligands, including MAMPs. We report that BAK1 depletion is linked to defense activation through the endogenous PROPEP peptides (Pep epitopes) and their LRR receptor kinases PEPR1/PEPR2, despite critical defects in MAMP signaling. In bak1-knockout plants, PEPR elicitation results in extensive cell death and the prioritization of salicylate-based defenses over jasmonate-based defenses, in addition to elevated proligand and receptor accumulation. BAK1 disruption stimulates the release of PROPEP3, produced in response to Pep application and during pathogen challenge, and renders PEPRs necessary for basal resistance. These findings are biologically relevant, since specific BAK1 depletion coincides with PEPR-dependent resistance to the fungal pathogen Colletotrichum higginsianum. Thus, the PEPR pathway ensures basal resistance when MAMP-triggered defenses are compromised by BAK1 depletion.

Biventricular repair of double-outlet right ventricle and closing ventricular septal defect.

We report an infant with double-outlet right ventricle and progressive left ventricular failure caused by a closing apical muscular ventricular septal defect detected during follow-up, who achieved successful biventricular repair after surgical opening and enlargement of a closed perimembranous ventricular septal defect.

The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance.

Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporthe oryzae and accomplish different functions in AVR recognition. RGA4 triggers an AVR-independent cell death that is repressed in the presence of RGA5 in both rice protoplasts and Nicotiana benthamiana. Upon recognition of the pathogen effector AVR-Pia by direct binding to RGA5, repression is relieved and cell death occurs. RGA4 and RGA5 form homo- and hetero-complexes and interact through their coiled-coil domains. Localization studies in rice protoplast suggest that RGA4 and RGA5 localize to the cytosol. Upon recognition of AVR-Pia, neither RGA4 nor RGA5 is re-localized to the nucleus. These results establish a model for the interaction of hetero-pairs of NB-LRRs in plants: RGA4 mediates cell death activation, while RGA5 acts as a repressor of RGA4 and as an AVR receptor.

Palmitoylation-dependent membrane localization of the rice resistance protein pit is critical for the activation of the small GTPase OsRac1.

Nucleotide binding domain and leucine-rich repeat (NLR)-containing family proteins function as intracellular immune sensors in both plants and animals. In plants, the downstream components activated by NLR family proteins and the immune response mechanisms induced by these downstream molecules are largely unknown. We have previously found that the small GTPase OsRac1, which acts as a molecular switch in rice immunity, is activated by Pit, an NLR-type resistance (R) protein to rice blast fungus, and this activation plays critical roles in Pit-mediated immunity. However, the sites and mechanisms of activation of Pit in vivo remain unknown. To clarify the mechanisms involved in the localization of Pit, we searched for consensus sequences in Pit that specify membrane localization and found a pair of potential palmitoylation sites in the N-terminal coiled-coil region. Although wild-type Pit was localized mainly to the plasma membrane, this membrane localization was compromised in a palmitoylation-deficient mutant of Pit. The palmitoylation-deficient Pit displayed significantly lower affinity for OsRac1 on the plasma membrane, thereby resulting in failures of the Pit-mediated cell death, the production of reactive oxygen species, and disease resistance to rice blast fungus. These results indicate that palmitoylation-dependent membrane localization of Pit is required for the interaction with and the activation of OsRac1 and that OsRac1 activation by Pit is vital for Pit-mediated disease resistance to rice blast fungus.

Successful biventricular repair of double-outlet right ventricle with transposition of the great arteries, pulmonary stenosis, and straddling mitral valve.

A 9-month-old boy with polysplenia, double-outlet right ventricle (DORV), transposition of the great arteries (TGA), a large ventricular septal defect (VSD), straddling mitral valve, pulmonary stenosis (PS), and a normal-sized pulmonary annulus underwent ventricular septation at the right side of the straddling mitral chord as well as an en bloc truncal switch procedure to minimize reduction of right ventricular (RV) volume from the intraventricular conduit. Echocardiography 5 months postoperatively showed laminar flow without obstruction through both ventricular outflow tracts, normal ventricular function, trivial aortic regurgitation, and mild pulmonary regurgitation (PR). This procedure is a good option for biventricular repair in the presence of a straddling mitral valve.

Case of congenital aneurysm of sinus of Valsalva with common arterial trunk.

We describe an unusual case of a patient with common arterial trunk and interrupted aortic arch, complicated by congenital aneurysm of the sinus of Valsalva, who underwent successful repair. To our knowledge, no such case has been reported in the English literature. The combination of common arterial trunk and congenital aneurysm of the sinus of Valsalva may yield insights into the morphogenesis of congenital aneurysm of the sinus of Valsalva.

Absent pulmonary valve, imperforate tricuspid valve, and dysplastic right ventricle.

We report a very rare case involving an absent pulmonary valve, an imperforate tricuspid valve, a ventricular septal defect (VSD), and a dysplastic right ventricle in a patient who underwent a Fontan operation successfully. Upon performing a bidirectional cavopulmonary anastomosis, we closed the VSD and coronary artery-to-right ventricle fistulae, and plicated the right ventricular free wall in order to obliterate the right ventricular cavity.

Takedown of Yasui procedure due to closed ventricular septal defect.

A two and a half year old girl who had undergone the Yasui procedure as a neonate for ventricular septal defect, subaortic stenosis, and interrupted aortic arch underwent follow-up catheterization 2 years postoperatively. It showed that the neo-left ventricular tract reconstructed by Damus-Kaye-Stansel anastomosis had occluded due to closure of the ventricular septal defect and residual subaortic stenosis at the original left ventricular outflow tract. The patient therefore underwent takedown of the Yasui procedure.

Sekiguchi lesion gene encodes a cytochrome P450 monooxygenase that catalyzes conversion of tryptamine to serotonin in rice.

Serotonin is a well known neurotransmitter in mammals and plays an important role in various mental functions in humans. In plants, the serotonin biosynthesis pathway and its function are not well understood. The rice sekiguchi lesion (sl) mutants accumulate tryptamine, a candidate substrate for serotonin biosynthesis. We isolated the SL gene by map-based cloning and found that it encodes CYP71P1 in a cytochrome P450 monooxygenase family. A recombinant SL protein exhibited tryptamine 5-hydroxylase enzyme activity and catalyzed the conversion of tryptamine to serotonin. This pathway is novel and has not been reported in mammals. Expression of SL was induced by the N-acetylchitooligosaccharide (chitin) elicitor and by infection with Magnaporthe grisea, a causal agent for rice blast disease. Exogenously applied serotonin induced defense gene expression and cell death in rice suspension cultures and increased resistance to rice blast infection in plants. We also found that serotonin-induced defense gene expression is mediated by the RacGTPase pathway and by the G alpha subunit of the heterotrimeric G protein. These results suggest that serotonin plays an important role in rice innate immunity.

Factors affecting systemic oxygen delivery after Norwood procedure with Sano modification.

BACKGROUND: The physiologic goal of management after a Norwood procedure is to optimize systemic oxygen delivery, as indicated by oxygen excess factor (OEF). Factors were examined that might affect systemic oxygen delivery after the Norwood procedure with right ventricle-to-pulmonary artery (RV-PA) conduit as the pulmonary blood supply. METHODS: Hemodynamic data of 9 patients (mean age, 25.0 days; mean weight, 2.9 kg) who underwent a modified Norwood operation for hypoplastic left heart syndrome (HLHS) between April 2003 and April 2008 were retrospectively analyzed. Variables were obtained by manometry and oximetry from indwelling catheters in the systemic artery, pulmonary artery, and superior vena cava at 3- to 6-hour intervals for 72 hours postoperatively. Systemic (Qs) and pulmonary (Qp) blood flow, systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were calculated. RESULTS: A significant increase in SVR and decrease in PVR occurred during the first 6 hours, which might be inductive to sudden cardiovascular collapse. SVR and PVR significantly decreased over time through 24 hours, followed by a lower steady increase. OEF was closely correlated with SVR (p < 0.0001). No correlation of OEF with PVR (p = 0.65) was noted among the assumed variables. Mixed venous oxygen saturation (SVO(2)) and OEF were strongly correlated. Pulmonary arterial pressure and OEF were weakly correlated. CONCLUSIONS: Postoperative management strategies to maintain a low SVR, rather than manipulating PVR, appear to be rational to achieve adequate oxygen delivery after a Norwood procedure with Sano modification. The SVO(2) provides reliable prediction of OEF during postoperative hemodynamic recovery.

Intracardiac Fontan procedure for heterotaxy syndrome with complex systemic and pulmonary venous anomalies.

OBJECTIVE: The extracardiac conduit procedure is widely used for patients with heterotaxy syndrome with complex systemic and pulmonary venous anomalies; however, it lacks conduit-growth potential and requires long-term anticoagulation. We present the intracardiac Fontan procedure, which eliminates the above-mentioned disadvantages. PATIENTS AND METHODS: Twenty-four patients (mean age, 4.1 years; weight, 13.0 kg) with heterotaxy syndrome underwent intracardiac Fontan operations between March 1995 and March 2008. In each patient, the anomalous systemic venous return with the isolated hepatic vein was redirected to the pulmonary artery using an intra-atrial baffle without obstructing the pulmonary venous pathway; this was accomplished by anterior (n=5), lateral (n=15) or posterior tunnel methods (n=4), depending on the anatomical relationship of the systemic and pulmonary venous pathways. RESULTS: There was one (4%) in-hospital and two (8%) late deaths in total. Five (21%) patients underwent re-operation for either pulmonary venous obstruction or supraventricular tachycardia. The actuarial 12-year survival was 86% (the Kaplan-Meier survival plot). The freedom from re-operation at 10 years was 77%. Anticoagulation was not required except for two patients (8%) who had prosthetic valves and coagulation disorder. Obstruction of the systemic venous pathway was not observed in any patient; however, five (20%) patients had clinically significant postoperative arrhythmias. At the final follow-up, all survivors were categorised as the New York Heart Association class I. CONCLUSIONS: Aided by detailed preoperative anatomical and physiological diagnoses, intracardiac Fontan procedures were technically feasible in patients with complex systemic and pulmonary venous anomalies. The specific cardiac anatomy in these patients warranted this procedure; however, taking into consideration the improved outcomes of the modified Fontan procedure, this method should be performed with deliberation.

Removal of an external stent of the bronchus.

We report a case of a patient who underwent removal of an external stent of the bronchus. She had undergone external stenting for tracheobronchomalacia. After removal of the external stent, the bronchus was just as widely patent as preoperative state.

Novel modification of total cavopulmonary connection for isolated hepatic vein.

A surgeon needs an innovative technique to establish a Fontan circulation for a patient who has a widely separated hepatic vein from the inferior vena cava. The inferior vena cava was redirected by placing a trimmed GoreTex baffle (W. L. Gore and Associates, Flagstaff, AZ) on the internal side of the atrium connecting the hepatic venous flow, and then directing it to the extra-atrium. Another extracardiac half-circumferential GoreTex baffle was sutured to the epicardial atrial wall and to the pulmonary artery opening. This procedure is efficacious for patients with an isolated hepatic vein and has advantages in terms of using less synthetic material in the conduit.

Rare type of congenital aneurysm of the right sinus of Valsalva protruding superiorly into the pericardial space.

We report a rare type of aneurysm of the sinus of Valsalva. The orifice of the aneurysm was in the right sinus of Valsalva and protruded superiorly, which is a direction not typical of right sinus of Valsalva aneurysms. Intraoperatively, it became clear that the aneurysm was located in the right sinus of Valsalva with extracardiac protrusion. Inspection through the aortotomy revealed that the orifice of the aneurysm opened between the orifice of the right coronary artery and the commissure between the right and left coronary cusps. The aneurysm was obliterated with a pledgeted suture from outside the orifice of the aneurysm. Early prophylactic surgical treatment of the aneurysm makes the operation simple and prevents subsequent development of complications, such as compression of the coronary artery, thrombosis, and/or spontaneous rupture.

Thrombotic occlusion of Blalock-Taussig shunt in a patient with unnoticed protein C deficiency.

A 6-month-old girl with a diagnosis of double-outlet right ventricle and pulmonary stenosis had a left modified Blalock-Taussig shunt. Chest computed tomography (CT) performed on postoperative day 11 showed good patency of the shunt. However, on postoperative day 16, oxygen saturation suddenly dropped below 40%, and chest CT showed thrombotic occlusion of the shunt. Urgent thrombectomy was performed successfully. Examination of coagulation factors revealed low levels of both the amount and activity of protein C (27% and 31%, respectively). Diagnosis of heterozygous hereditary protein C deficiency was made, and the patient was placed on warfarin. She is currently in good condition.

Transition of ventricular function and energy efficiency after a primary or staged Fontan procedure.

PURPOSE: The transitional changes of the ventricular function at different time points after total cavopulmonary connection (TCPC) were examined. METHODS: A total of 29 patients were divided into a primary TCPC group and a staged TCPC group. In both groups, phase I was defined as within 2 months after TCPC and phase II as beyond at least a year after TCPC. Changes in ventricular end-diastolic volume (EDV), ventricular end-systolic elastance (Ees), effective arterial elastance (Ea), and ventriculoarterial coupling (Ea/Ees) were evaluated. RESULTS: The results for the primary TCPC group are as follows. Phase I: The EDV decreased (P < 0.05). The Ees and Ea both increased (P < 0.05). Ea/Ees showed a tendency to increase (P = 0.08). Phase II: The EDV decreased (P < 0.05). The Ees increased significantly, and Ea showed no significant change. Ees/Ea showed a tendency to decrease (P = 0.07). The results for the staged TCPC group were as follows. Phase I: The EDV decreased significantly after bidirectional cavopulmonary shunt (BCPS). The Ees showed no significant change after BCPS and TCPC. Although Ea increased after BCPS (P < 0.05), it showed no significant change after TCPC. Ea/Ees showed no significant change. Phase II: The Ees increased (P < 0.05) without significant changes of EDV and Ea. As a result, Ea/Ees showed a tendency to decrease. CONCLUSION: This study suggested improved ventricular function in both groups. These results suggest hemodynamic adaptation to the Fontan circulation. The deleterious effects on ventricular function caused by the Fontan procedure disappeared within a couple of years. This acute effect can be ameliorated by the staged approach to the Fontan circulation.

Creation of an intraatrial tunnel to produce a total cavo-pulmonary connection in a patient with dominant right ventricle, totally anomalous pulmonary venous connection, and pulmonary atresia with non-confluent pulmonary arteries.

The surgical strategy for patients having a functionally single ventricle associated with totally anomalous pulmonary venous connection and pulmonary atresia with non-confluent pulmonary artery has yet to be agreed. We created an intraatrial tunnel to produce a total cavo-pulmonary connection in such a patient, also creating a confluence for the pulmonary arteries. By minimizing the use of the GoreTex patch, the patient was able to discontinue the use of warfarin.