Microbiology of Big Soda Lake, a multi-extreme meromictic volcanic crater lake in the Nevada desert.

Big Soda Lake, Nevada, is a multi-extreme meromictic lake, whose hypersaline hyperalkaline bottom waters feature permanent anoxia and high concentrations of arsenic, sulphide and ammonia. These properties make Big Soda Lake-and the adjacent Little Soda Lake-a fascinating system for exploring life's boundaries, discovering novel microbial taxa and identifying biotechnologically useful strains. To date, the taxonomic diversity and metabolic capabilities of microorganisms in this system remain largely unknown. Here, we fill this gap using microbiome surveys across the Big and Little Soda Lake water columns, including 16S rRNA sequencing, fungal ITS2 sequencing and gene- and genome-resolved metagenomics. We accompany these surveys with measurements of salinity, pH, temperature, oxygen, ammonium and ammonia concentrations. Our analyses reveal rich bacterial communities, taxonomically and functionally differentiated along Big Soda Lake's oxycline and, to lesser extent, between lakes. Fungal communities were dominated by a small number of families, while nearly no archaea were detected. Pathways related to perchlorate reduction, anoxygenic phototrophy, fermentation, dissimilatory metabolism of arsenite/arsenate, sulphur compounds, nitrogen compounds and hydrogen, were particularly prevalent. A total of 129 high-quality bacterial and archaeal metagenome-assembled genomes (completeness ≥ 80%, contamination ≤ 5%) were recovered, yielding insight into the taxonomic distribution of microbial metabolic pathways.

Coated poly-4-hydroxybutyrate (Phasix ST™) mesh is safe and effective for hiatal hernia repair: our institutional experience and review of the literature.

BACKGROUND: Poly-4-hydroxybutyrate (P4HB) is a bioabsorbable mesh with a non-adhesive coating on one side that is being used to reinforce the hiatus during hiatal hernia repair; however, there is limited data regarding its use. The aim of this study was to investigate outcomes after hiatal hernia repair using this mesh at our institution and through a review of the literature. METHODS: An institutional review board-approved prospective database was retrospectively reviewed for all patients undergoing hiatal hernia repair from April 2018 to December 2022. A systematic review with meta-analysis was conducted to evaluate outcomes using P4HB coated mesh. RESULTS: In our institutional cohort, there were 230 patients (59 males; 171 females) with a mean follow-up of 20 ± 14.6 months. No mesh-related complications occurred. Hernia recurrence was diagnosed in 11 patients (4.8%) with a median time to recurrence of 16 months. In the systematic review, 4 studies with 221 patients (76 males; 145 females) were included. Median follow-up ranged from 12 to 27 months. Recurrence rate in these studies was reported from 0 to 8.8%, with a total of 12 recurrences identified. Like our institutional cohort, no mesh-related complications were reported. After our recurrences were combined with those from the systematic review, a total of 23 recurrences were included in the meta-analysis. Our meta-analysis revealed a low recurrence rate following hiatal hernia repair with P4HB coated mesh (incidence rate per 100 person-years, 2.82; 95% confidence interval, 1.60, 4.04). CONCLUSION: P4HB coated mesh is safe and effective for hiatal hernia repairs.

Cellular transduction of mechanical oscillations in plants by the plasma-membrane mechanosensitive channel MSL10.

Plants spend most of their life oscillating around 1-3 Hz due to the effect of the wind. Therefore, stems and foliage experience repetitive mechanical stresses through these passive movements. However, the mechanism of the cellular perception and transduction of such recurring mechanical signals remains an open question. Multimeric protein complexes forming mechanosensitive (MS) channels embedded in the membrane provide an efficient system to rapidly convert mechanical tension into an electrical signal. So far, studies have mostly focused on nonoscillatory stretching of these channels. Here, we show that the plasma-membrane MS channel MscS-LIKE 10 (MSL10) from the model plant Arabidopsis thaliana responds to pulsed membrane stretching with rapid activation and relaxation kinetics in the range of 1 s. Under sinusoidal membrane stretching MSL10 presents a greater activity than under static stimulation. We observed this amplification mostly in the range of 0.3-3 Hz. Above these frequencies the channel activity is very close to that under static conditions. With a localization in aerial organs naturally submitted to wind-driven oscillations, our results suggest that the MS channel MSL10, and by extension MS channels sharing similar properties, represents a molecular component allowing the perception of oscillatory mechanical stimulations by plants.

The use of suboptimal antiretroviral therapy when applying for migration to Australia: a case series.

Background Australia imposes restrictions for people living with HIV (PLHIV) applying for permanent residency (PR), including spending less than AUD51,000 on medical costs over 10years. Some PLHIV opted for suboptimal and cheaper antiretroviral therapy (ART) regimens to increase their chances of receiving PR. We collated a case series to examine PLHIV on suboptimal ART because of visa issues. Methods We identified all patients applying for a PR in Australia who obtained nevirapine, efavirenz or zidovudine between July 2022 and July 2023 from the Melbourne Sexual Health Centre. Pathology results and records detailing psychological issues relating to the patients' wishes to remain on suboptimal ART were extracted from clinical records by two researchers. Results We identified six patients with a mean age of 39years migrating from Asian and European countries. Three patients used efavirenz, and three used nevirapine. All desired to remain on cheaper, suboptimal ART to stay below visa cost thresholds, which they considered to aid favourably with their application. Four displayed stress and anxiety arising from visa rejections, appeal deadlines and the lengthy visa application process. Conclusions Despite access to more effective and safer ART, we identified patients who chose to remain on cheaper ART to improve chances of obtaining an Australian visa, potentially putting their health at risk. We found significant evidence of stress and anxiety among patients. There is a need to review and revise current migration policies and laws in Australia that discriminate against PLHIV and jeopardise public health.

Content Analysis of Three-Dimensional Model Technologies and Applications for Construction: Current Trends and Future Directions.

The proliferation of digital technologies is substantially transforming inspection methodologies for construction activities. Although the implementation of a three-dimensional (3D) model has emerged as an advantageous, feasible inspection application, the selection of the most suitable 3D models is challenging due to multiple technology options. The primary objectives of this study were to investigate current trends and identify future technologies for 3D models in the construction industry. This study utilized systematic reviews by identifying and selecting quality journals, analyzing selected articles, and conducting content analysis and meta-analysis to identify dominant themes in 3D models. Results showed that the top technologies used to model construction projects are building information models, remote sensing, stereo vision system/photo processing programs, and augmented reality/virtual reality. The main benefits and challenges of these technologies for modeling were also determined. This study identified three areas with significant knowledge gaps for future research: (1) the amalgamation of two or more technologies to overcome project obstacles; (2) solution optimization for inspections in remote areas; and (3) the development of algorithm-based technologies. This research contributes to the body of knowledge by exploring current trends and future directions of 3D model technologies in the construction industry.

Gastric per-oral endoscopic myotomy versus pyloric injection of botulinum toxin for the treatment of gastroparesis: our institutional experience and a systematic review of the literature.

INTRODUCTION: Gastric Per-Oral Endoscopic Myotomy (GPOEM) has been developed as an effective treatment option for patients with medically refractory gastroparesis. Other endoscopic options, such as pyloric injection of botulinum toxin (Botox), is often performed with limited efficacy. The purpose of this study was to evaluate GPOEM for the treatment of gastroparesis and compare its efficacy to Botox injection results reported in the literature. METHODS: A retrospective review was conducted to identify all patients who underwent a GPOEM for the treatment of gastroparesis between September 2018 and June 2022. Changes in Gastric Emptying Scintigraphy (GES) studies and Gastroparesis Cardinal Symptom (GCSI) scores from the preoperative to postoperative period were analyzed. In addition, a systematic review was conducted to identify all publications reporting the outcomes of Botox injections for the treatment of gastroparesis. RESULTS: A total of 65 patients (51 female, 14 male) underwent a GPOEM during the study period. Twenty-eight patients (22 female, 6 male) had both preoperative and postoperative GES studies in addition to GCSI scores. The etiologies of gastroparesis were diabetic (n = 4), idiopathic (n = 18), and postsurgical (n = 6). Fifty percent of these patients had undergone previous failed interventions including Botox injections (n = 6), gastric stimulator placement (n = 2), and endoscopic pyloric dilation (n = 6). Outcomes showed a significant decrease in GES percentages (mean difference = - 23.5%, p < 0.001) and GCSI scores (mean difference = - 9.6, p = 0.02) postoperatively. In the systematic review for Botox, transient mean improvements in postoperative GES percentages and GCSI scores were reported at 10.1% and 4.0, respectively. CONCLUSION: GPOEM leads to significant improvement in GES percentages and GCSI scores postoperatively and is superior to Botox injection results reported in the literature.

Cyclic peptides can engage a single binding pocket through highly divergent modes.

Cyclic peptide library screening technologies show immense promise for identifying drug leads and chemical probes for challenging targets. However, the structural and functional diversity encoded within such libraries is largely undefined. We have systematically profiled the affinity, selectivity, and structural features of library-derived cyclic peptides selected to recognize three closely related targets: the acetyllysine-binding bromodomain proteins BRD2, -3, and -4. We report affinities as low as 100 pM and specificities of up to 106-fold. Crystal structures of 13 peptide-bromodomain complexes reveal remarkable diversity in both structure and binding mode, including both α-helical and ß-sheet structures as well as bivalent binding modes. The peptides can also exhibit a high degree of structural preorganization. Our data demonstrate the enormous potential within these libraries to provide diverse binding modes against a single target, which underpins their capacity to yield highly potent and selective ligands.

Factors associated with regular dental attendance by aged adults: A systematic review.

OBJECTIVES: To determine factors influencing regular dental attendance in aged adults 65 and over according to Andersen's Behavioural Model. BACKGROUND: Regular attendance for dental visits is vital to improve and maintain oral health, quality of life and general well-being. Aged adults 65 years and older experience barriers to regular dental attendance, which in turn leads to an increased risk for oral diseases. MATERIALS AND METHODS: An electronic search was undertaken in April 2021 in Cochrane, Embase, Medline, Cinahl, Dentistry & Oral Science Source via EBSCOhost and Embase for papers on factors influencing the frequency of attendance by older people. Risk of bias was assessed according to the Newcastle-Ottawa Scale for cohort and case-control studies, and with modified version of this tool for cross-sectional studies. Frequency effect size was calculated for factors described in Andersen's Behavioural Model (predisposing, enabling and needs-related). RESULTS: Twenty-one studies were eligible for inclusion. Factors frequently investigated affecting regular dental attendance included: age, gender, education (predisposing); income, and social support (enabling); and remaining teeth, pain, perceived health (needs-related). Income was the only factors with a 100% positive association with regular dental attendance. CONCLUSIONS: This systematic review confirms the complex interconnectedness of several factors and dental attendance in older adults. A number of factors were identified which warrant further investigation to improve access to dental care to socio-economically vulnerable older populations.

Mechanosensitive ion channels contribute to mechanically evoked rapid leaflet movement in Mimosa pudica.

Mechanoperception, the ability to perceive and respond to mechanical stimuli, is a common and fundamental property of all forms of life. Vascular plants such as Mimosa pudica use this function to protect themselves against herbivory. The mechanical stimulus caused by a landing insect triggers a rapid closing of the leaflets that drives the potential pest away. While this thigmonastic movement is caused by ion fluxes accompanied by a rapid change of volume in the pulvini, the mechanism responsible for the detection of the mechanical stimulus remains poorly understood. Here, we examined the role of mechanosensitive ion channels in the first step of this evolutionarily conserved defense mechanism: the mechanically evoked closing of the leaflet. Our results demonstrate that the key site of mechanosensation in the Mimosa leaflets is the pulvinule, which expresses a stretch-activated chloride-permeable mechanosensitive ion channel. Blocking these channels partially prevents the closure of the leaflets following mechanical stimulation. These results demonstrate a direct relation between the activity of mechanosensitive ion channels and a central defense mechanism of M. pudica.

Workforce Trends of Underrepresented Minority Nurses in the United States Over the Last Decade: Progress Towards Equal Representation?

A healthcare workforce representative of the race/ethnicity composition of the population it serves is central to addressing systemic health inequities. The aim of this study was to assess workforce trends of underrepresented minority (URM) nurses using the National Sample Survey of Registered Nurses years 2008 and 2018 and the American Community Survey years 2010 and 2019. We examined changes over time in URM composition (Black/African American (B/AA), Latine, American Indian/Alaskan Native (AI/AN), Native Hawaiian/Pacific Islander (NH/PI)) for registered nurses (RN), nurse practitioners (NPs), educational attainment (diploma/associate, BSN, MS(N)/PhD), job type (patient care, research, administration/supervision, teaching, other), and rural/urban location using descriptive statistics and bivariate regressions. While the proportion of the URM RN workforce grew significantly, the only URM group demonstrating proportional gains in the APRN workforce were Latine nurses. URM representation in educational attainment grew across all degree types. By 2018/2019, Latine nurses have their largest representation in the Dipl./ASN degree group and saw a proportional decline for PhD educated nurses. B/AA nurses have their largest representation at the MS(N)/PhD level. However, smaller proportions of B/AA nurses were working as APRNs compared to their non-URM colleagues. At the PhD level, few B/AA nurses were represented in research and teaching positions. A subgroup analysis of unemployed nurses seeking work revealed that B/AA and AI/AN nurses were overrepresented among unemployed nurses. While today's nursing workforce is more representative of the nation than ever before, results show unequal representation of URM and non-URM nurses across the ranks of the nursing professions that suggest unequal career and labor market opportunities.

Erratum: Tran et al. Early Cellular Responses Induced by Sedimentary Calcite-Processed Particles in Bright Yellow 2 Tobacco Cultured Cells. Int. J. Mol. Sci. 2020, 21, 4279.

The authors would like to remove the scientific consortium 'Camille Nous' from the author list and the Author Contributions section in the published paper [...].

Are we doing too many non-therapeutic laparotomies in trauma? An analysis of the National Trauma Data Bank.

BACKGROUND: Exploratory laparotomy (EL) has been the definitive diagnostic and therapeutic modality for operative abdominal trauma in the US. Recently, many trauma centers have started using diagnostic laparoscopy (DL) in stable trauma patients in an effort to reduce the incidence of non-therapeutic laparotomy (NL). We aim to evaluate the incidence of NL in the trauma population in the US and compare the outcomes between DL and NL. METHODS: Using ICD-9 codes, the National Trauma Data Bank (2010-2015) was queried for patients undergoing any abdominal surgical intervention. Patients were divided into two groups: diagnostic laparoscopy (DL) and exploratory laparotomy (EL). Hemodynamically unstable patients on arrival and patients with abbreviated injury score (AIS) > 3 were excluded. Patients in EL group without any codes for gastrointestinal, diaphragmatic, hepatic, splenic, vascular, or urological procedures were considered to have undergone NL. After excluding patients who were converted to open from the DL group, multivariate regression models were used to analyze the outcomes of DL vs NL group with respect to mortality, length of stay, and complications. RESULTS: A total of 3197 patients underwent NL vs 1323 patients who underwent DL. Compared to DL group, the NL group were older (mean age: 35 vs. 31, P < 0.01). Rate of penetrating injury was 77% vs 86% for patients in NL vs DL. On multivariate analysis, NL was associated with increased mortality (OR 4.5, 95% CI 2.1-9.7), higher rate of complications (OR 2.2, 95% CI 1.4-3.3), and a longer hospital stay (OR 2.7, 95% CI 2.1-3.5). NL was also associated with higher rates of pneumonia, VTE, ARDS, and cardiac arrest. CONCLUSION: With increasing experience in minimally invasive surgery, DL should be a part of the armamentarium of trauma surgeons. This study supports that in well-selected trauma patients DL has favorable outcomes compared to NL. These findings warrant further investigation.

Early Cellular Responses Induced by Sedimentary Calcite-Processed Particles in Bright Yellow 2 Tobacco Cultured Cells.

Calcite processed particles (CaPPs, Megagreen®) elaborated from sedimentary limestone rock, and finned by tribomecanic process were found to increase photosynthetic CO2 fixation grapevines and stimulate growth of various cultured plants. Due to their processing, the CaPPs present a jagged shape with some invaginations below the micrometer size. We hypothesised that CaPPs could have a nanoparticle (NP)-like effects on plants. Our data show that CaPPs spontaneously induced reactive oxygen species (ROS) in liquid medium. These ROS could in turn induce well-known cellular events such as increase in cytosolic Ca2+, biotic ROS generation and activation of anion channels indicating that these CaPPs could activate various signalling pathways in a NP-like manner.

Methanol induces cytosolic calcium variations, membrane depolarization and ethylene production in arabidopsis and tobacco.

Background and Aims: Methanol is a volatile organic compound released from plants through the action of pectin methylesterases (PMEs), which demethylesterify cell wall pectins. Plant PMEs play a role in developmental processes but also in responses to herbivory and infection by fungal or bacterial pathogens. However, molecular mechanisms that explain how methanol could affect plant defences remain poorly understood. Methods: Using cultured cells and seedlings from Arabidopsis thaliana and tobacco BY2 expressing the apoaequorin gene, allowing quantification of cytosolic Ca2+, a reactive oxygen species (ROS) probe (CLA, Cypridina luciferin analogue) and electrophysiological techniques, we followed early plant cell responses to exogenously supplied methanol applied as a liquid or as volatile. Key Results: Methanol induces cytosolic Ca2+ variations that involve Ca2+ influx through the plasma membrane and Ca2+ release from internal stores. Our data further suggest that these Ca2+ variations could interact with different ROS and support a signalling pathway leading to well known plant responses to pathogens such as plasma membrane depolarization through anion channel regulation and ethylene synthesis. Conclusions: Methanol is not only a by-product of PME activities, and our data suggest that [Ca2+]cyt variations could participate in signalling processes induced by methanol upstream of plant defence responses.

Simulated patient and role play methodologies for communication skills training in an undergraduate medical program: Randomized, crossover trial.

Background: Educators utilize real patients, simulated patients (SP), and student role play (RP) in communication skills training (CST) in medical curricula. The chosen modality may depend more on resource availability than educational stage and student needs. In this study, we set out to determine whether an inexpensive volunteer SP program offered an educational advantage compared to RP for CST in preclinical medical students. Methods: Students and volunteer SPs participated in interactions across two courses. Students allocated to SP interactions in one course participated in RP in the other course and vice versa. Audio recordings of interactions were made, and these were rated against criterion descriptors in a modified Calgary-Cambridge Referenced Observation Guide. Results: Independent t-test scores comparing ratings of RP and SP groups revealed no significant differences between methodologies. Discussion: This study demonstrates that volunteer SPs are not superior to RP, when used in CST targeted at preclinical students. This finding is consistent with existing literature, yet we suggest that it is imperative to consider the broader purpose of CST and the needs of stakeholders. Consequently, it may be beneficial to use mixed methods of CST in medical programs.

Pulmonary effects of aging.

PURPOSE OF REVIEW: As the population ages, the increase in chronic illnesses among patients with decreasing lung function will pose a major public health challenge. Determining which elderly patients are fit for surgery is an increasingly important skill. Anesthetic care of elderly patients requires an understanding of the effects that chronic diseases have on normal age-related changes in physiology and function. Postoperative respiratory complications are significantly increased in patients over 65 years of age, especially those with preexisting diseases. RECENT FINDINGS: Advanced age is associated with changes in the immunity of the pulmonary system. Dysregulation of pro-inflammatory mediators and antimicrobial defense systems contribute to a reduction in pulmonary function and its response to infections. Aging is also associated with a disruption of the function of alveolar macrophages, neutrophils, and natural killer cells. SUMMARY: Aging can increase the risk of postoperative complications because of a loss of physiologic reserve and airway defenses. These limitations may only become apparent after the stressors of surgery and anesthesia.

Percutaneous Gastrostomy Device for the Treatment of Class II and Class III Obesity: Results of a Randomized Controlled Trial.

OBJECTIVES: The AspireAssist System (AspireAssist) is an endoscopic weight loss device that is comprised of an endoscopically placed percutaneous gastrostomy tube and an external device to facilitate drainage of about 30% of the calories consumed in a meal, in conjunction with lifestyle (diet and exercise) counseling. METHODS: In this 52-week clinical trial, 207 participants with a body-mass index (BMI) of 35.0-55.0 kg/m2 were randomly assigned in a 2:1 ratio to treatment with AspireAssist plus Lifestyle Counseling (n=137; mean BMI was 42.2±5.1 kg/m2) or Lifestyle Counseling alone (n=70; mean BMI was 40.9±3.9 kg/m2). The co-primary end points were mean percent excess weight loss and the proportion of participants who achieved at least a 25% excess weight loss. RESULTS: At 52 weeks, participants in the AspireAssist group, on a modified intent-to-treat basis, had lost a mean (±s.d.) of 31.5±26.7% of their excess body weight (12.1±9.6% total body weight), whereas those in the Lifestyle Counseling group had lost a mean of 9.8±15.5% of their excess body weight (3.5±6.0% total body weight) (P<0.001). A total of 58.6% of participants in the AspireAssist group and 15.3% of participants in the Lifestyle Counseling group lost at least 25% of their excess body weight (P<0.001). The most frequently reported adverse events were abdominal pain and discomfort in the perioperative period and peristomal granulation tissue and peristomal irritation in the postoperative period. Serious adverse events were reported in 3.6% of participants in the AspireAssist group. CONCLUSIONS: The AspireAssist System was associated with greater weight loss than Lifestyle Counseling alone.

Automated Affinity Capture and On-Tip Digestion to Accurately Quantitate in Vivo Deamidation of Therapeutic Antibodies.

Deamidation of therapeutic antibodies may result in decreased drug activity and undesirable changes in pharmacokinetics and immunogenicity. Therefore, it is necessary to monitor the deamidation levels [during storage] and after in vivo administration. Because of the complexity of in vivo samples, immuno-affinity capture is widely used for specific enrichment of the target antibody prior to LC-MS. However, the conventional use of bead-based methods requires large sample volumes and extensive processing steps. Furthermore, with automation difficulties and extended sample preparation time, bead-based approaches may increase artificial deamidation. To overcome these challenges, we developed an automated platform to perform tip-based affinity capture of antibodies from complex matrixes with rapid digestion and peptide elution into 96-well microtiter plates followed by LC-MS analysis. Detailed analyses showed that the new method presents high repeatability and reproducibility with both intra and inter assay CVs < 8%. Using the automated platform, we successfully quantified the levels of deamidation of a humanized monoclonal antibody in cynomolgus monkeys over a time period of 12 weeks after administration. Moreover, we found that deamidation kinetics between in vivo samples and samples stressed in vitro at neutral pH were consistent, suggesting that the in vitro stress test may be used as a method to predict the liability to deamidation of therapeutic antibodies in vivo.

Lower Extremity Arterial Reconstruction in Octogenarians and Older.

BACKGROUND: Despite previous single-institution studies showing that lower extremity arterial reconstruction (LEAR) in octogenarians and older patients may be undertaken with acceptable postoperative morbidity and mortality, there continues to be significant reluctance, in the vascular surgical community, to undertaking these complex revascularization procedures in this very elderly population. We undertook this study in an effort to determine the outcomes of LEAR in octogenarians and older patients on a national level. METHODS: The American College of Surgeons' National Surgical Quality Improvement Program database was queried to identify all patients who underwent LEAR between January 1, 2005 and December 31, 2009. Patient demographics and presenting comorbidities were recorded, and multivariate analyses were performed to compare outcomes in patients 80 and older to those in younger patients. RESULTS: There were 19,028 patients who underwent open infrainguinal LEAR during this time period. Patients ≥80 comprised 18% (3,486 patients), and patients <80 years comprised 82% (15,542 patients). Multivariate analysis demonstrated that patients aged ≥80 years had an increased likelihood of mortality (odds ratio [OR] 1.79; 95% confidence interval [CI] 1.42-2.26), cardiovascular (OR, 1.46; 95% CI, 1.12-1.89), respiratory (OR, 1.37; 95% CI, 1.12-1.67), and renal (OR, 1.57; 95% CI, 1.27-1.95) complications. There was, however, no significant difference in the likelihood of graft failure (OR, 1.04; 95% CI, 0.86-1.27), wound infection (OR, 0.92; 95% CI, 0.79-1.06), or major amputation (OR, 0.59; 95% CI, 0.13-2.74) between these 2 groups. CONCLUSIONS: LEAR in octogenarians is associated with an increased risk of postoperative morbidity and mortality but no increased risk of wound infection, amputation, or graft failure.

Acetylated 1,3-diaminopropane antagonizes abscisic acid-mediated stomatal closing in Arabidopsis.

Faced with declining soil-water potential, plants synthesize abscisic acid (ABA), which then triggers stomatal closure to conserve tissue moisture. Closed stomates, however, also create several physiological dilemmas. Among these, the large CO2 influx required for net photosynthesis will be disrupted. Depleting CO2 in the plant will in turn bias stomatal opening by suppressing ABA sensitivity, which then aggravates transpiration further. We have investigated the molecular basis of how C3 plants resolve this H2 O-CO2 conflicting priority created by stomatal closure. Here, we have identified in Arabidopsis thaliana an early drought-induced spermidine spermine-N(1) -acetyltransferase homolog, which can slow ABA-mediated stomatal closure. Evidence from genetic, biochemical and physiological analyses has revealed that this protein does so by acetylating the metabolite 1,3-diaminopropane (DAP), thereby turning on the latter's intrinsic activity. Acetylated DAP triggers plasma membrane electrical and ion transport properties in an opposite way to those by ABA. Thus in adapting to low soil-water availability, acetyl-DAP could refrain stomates from complete closure to sustain CO2 diffusion to photosynthetic tissues.