Sky Image Classification Based on Transfer Learning Approaches.

Cloudy conditions at a local scale pose a significant challenge for forecasting renewable energy generation through photovoltaic panels. Consequently, having real-time knowledge of sky conditions becomes highly valuable. This information could inform decision-making processes in system operations, such as determining whether conditions are favorable for activating a standalone system requiring a minimum level of radiation or whether sky conditions might lead to higher energy consumption than generation during adverse cloudy conditions. This research leveraged convolutional neural networks (CNNs) and transfer learning (TL) classification techniques, testing various architectures from the EfficientNet family and two ResNet models for classifying sky images. Cross-validation methods were applied across different experiments, where the most favorable outcome was achieved with the EfficientNetV2-B1 and EfficientNetV2-B2 models boasting a mean Accuracy of 98.09%. This study underscores the efficacy of the architectures employed for sky image classification, while also highlighting the models yielding the best results.

An Explainable Artificial Intelligence Software Tool for Weight Management Experts (PRIMO): Mixed Methods Study.

BACKGROUND: Predicting the likelihood of success of weight loss interventions using machine learning (ML) models may enhance intervention effectiveness by enabling timely and dynamic modification of intervention components for nonresponders to treatment. However, a lack of understanding and trust in these ML models impacts adoption among weight management experts. Recent advances in the field of explainable artificial intelligence enable the interpretation of ML models, yet it is unknown whether they enhance model understanding, trust, and adoption among weight management experts. OBJECTIVE: This study aimed to build and evaluate an ML model that can predict 6-month weight loss success (ie, ≥7% weight loss) from 5 engagement and diet-related features collected over the initial 2 weeks of an intervention, to assess whether providing ML-based explanations increases weight management experts' agreement with ML model predictions, and to inform factors that influence the understanding and trust of ML models to advance explainability in early prediction of weight loss among weight management experts. METHODS: We trained an ML model using the random forest (RF) algorithm and data from a 6-month weight loss intervention (N=419). We leveraged findings from existing explainability metrics to develop Prime Implicant Maintenance of Outcome (PRIMO), an interactive tool to understand predictions made by the RF model. We asked 14 weight management experts to predict hypothetical participants' weight loss success before and after using PRIMO. We compared PRIMO with 2 other explainability methods, one based on feature ranking and the other based on conditional probability. We used generalized linear mixed-effects models to evaluate participants' agreement with ML predictions and conducted likelihood ratio tests to examine the relationship between explainability methods and outcomes for nested models. We conducted guided interviews and thematic analysis to study the impact of our tool on experts' understanding and trust in the model. RESULTS: Our RF model had 81% accuracy in the early prediction of weight loss success. Weight management experts were significantly more likely to agree with the model when using PRIMO (χ2=7.9; P=.02) compared with the other 2 methods with odds ratios of 2.52 (95% CI 0.91-7.69) and 3.95 (95% CI 1.50-11.76). From our study, we inferred that our software not only influenced experts' understanding and trust but also impacted decision-making. Several themes were identified through interviews: preference for multiple explanation types, need to visualize uncertainty in explanations provided by PRIMO, and need for model performance metrics on similar participant test instances. CONCLUSIONS: Our results show the potential for weight management experts to agree with the ML-based early prediction of success in weight loss treatment programs, enabling timely and dynamic modification of intervention components to enhance intervention effectiveness. Our findings provide methods for advancing the understandability and trust of ML models among weight management experts.

Analysis on driving factors of microbial community succession in Jiuyao of Shaoxing Huangjiu (Chinese yellow rice wine).

The microbial ecosystem of fermented food is greatly disturbed by human activities.Jiuyao is important saccharification starter for brewing huangjiu. The interaction between environmental factors and microorganisms significantly affected the microbial community structure at different stages of Jiuyao manufacturing. This study combined environmental factor analysis and high-throughput sequencing technology to comprehensively analyze the specific changes of microbial community and environmental factors in each fermentation stage of Jiuyao production and their correlation. The results showed that the activities of liquefaction enzyme, glycosylation enzyme and acid protease reached the highest value on the 8 th day (192 h) after the beginning of fermentation, and the cellulase activity reached the highest value at the end of fermentation. Pediococcus（37.5 %-58.2 %）, Weissella（9.2 %-27.0 %） and Pelomonas（0.1 %-12.1 %） were the main microbial genera in the genus bacteria, and Saccharomycopsis（37.1 %-52.0 %）, Rhizopus（12.5 %-31.0 %） and Saccharomyces（4.0 %-20.5 %） were the main microbial genera in the genus fungi. The results of correlation analysis showed that the microbial communities in Jiuyao were closely related to environmental factors. Most microbial communities were positively correlated with temperature, but negatively correlated with ambient humidity, CO2 concentration, acidity and water content of Jiuyao. In addition, the transcription levels of enzymes related to microbial glucose metabolism in Jiuyao were higher in the late stage of Jiuyao fermentation. Interestingly, these enzymes had high transcription levels in fungi such as Saccharomycopsis, Rhizopus and Saccharomyces, as well as in bacteria such as Pediococcus and Lactobacillus. This study provides a reference for revealing the succession rule of microbial community structure caused by environmental factors during the preparation of Jiuyao in Shaoxing Huangjiu.

Rationale and design of the SenseWhy project: A passive sensing and ecological momentary assessment study on characteristics of overeating episodes.

Objectives: Overeating interventions and research often focus on single determinants and use subjective or nonpersonalized measures. We aim to (1) identify automatically detectable features that predict overeating and (2) build clusters of eating episodes that identify theoretically meaningful and clinically known problematic overeating behaviors (e.g., stress eating), as well as new phenotypes based on social and psychological features. Method: Up to 60 adults with obesity in the Chicagoland area will be recruited for a 14-day free-living observational study. Participants will complete ecological momentary assessments and wear 3 sensors designed to capture features of overeating episodes (e.g., chews) that can be visually confirmed. Participants will also complete daily dietitian-administered 24-hour recalls of all food and beverages consumed. Analysis: Overeating is defined as caloric consumption exceeding 1 standard deviation of an individual's mean consumption per eating episode. To identify features that predict overeating, we will apply 2 complementary machine learning methods: correlation-based feature selection and wrapper-based feature selection. We will then generate clusters of overeating types and assess how they align with clinically meaningful overeating phenotypes. Conclusions: This study will be the first to assess characteristics of eating episodes in situ over a multiweek period with visual confirmation of eating behaviors. An additional strength of this study is the assessment of predictors of problematic eating during periods when individuals are not on a structured diet and/or engaged in a weight loss intervention. Our assessment of overeating episodes in real-world settings is likely to yield new insights regarding determinants of overeating that may translate into novel interventions.

Draft Genome Sequence of Priestia sp. Strain TSO9, a Plant Growth-Promoting Bacterium Associated with Wheat (Triticum turgidum subsp. durum) in the Yaqui Valley, Mexico.

Strain TSO9 was isolated from a commercial field of wheat (Triticum turgidum L. subsp. durum) located in the Yaqui, Valley, Mexico. Here, the genome of this strain was sequenced, obtaining a total of 5,248,515 bp; 38.0% G + C content; 1,186,514 bp N50; and 2 L50. Based on the 16S rRNA gene sequencing, strain TSO9 was affiliated with the genus Priestia. The genome annotation of Priestia sp. TSO9 contains a total of 147 RNAs, 128 tRNAs, 1 tmRNA, and 5512 coding DNA sequences (CDS) distributed into 332 subsystems, where CDS associated with agricultural purposes were identified, such as (i) virulence, disease, and defense (57 CDS) (i.e., resistance to antibiotics and toxic compounds (34 CDS), invasion and intracellular resistance (12 CDS), and bacteriocins and ribosomally synthesized antibacterial peptides (10 CDS)), (ii) iron acquisition and metabolism (36 CDS), and (iii) secondary metabolism (4 CDS), i.e., auxin biosynthesis. In addition, subsystems related to the viability of an active ingredient for agricultural bioproducts were identified, such as (i) stress response (65 CDS). These genomic traits are correlated with the metabolic background of this strain, and its positive effects on wheat growth regulation reported in this work. Thus, further investigations of Priestia sp. TSO9 are necessary to complement findings regarding its application in agroecosystems to increase wheat yield sustainably.

5-Aminolevulinic Acid and 24-Epibrassinolide Improve the Drought Stress Resilience and Productivity of Banana Plants.

Plant growth, development, and productivity are adversely affected under drought conditions. Previous findings indicated that 5-aminolevulinic acid (ALA) and 24-epibrassinolide (EBL) play an important role in the plant response to adverse environmental conditions. This study demonstrated the role of ALA and EBL on oxidative stress and photosynthetic capacity of drought-stressed 'Williams' banana grown under the Egyptian semi-arid conditions. Exogenous application of either ALA or EBL at concentrations of 15, 30, and 45 mg·L-1 significantly restored plant photosynthetic activity and increased productivity under reduced irrigation; this was equivalent to 75% of the plant's total water requirements. Both compounds significantly reduced drought-induced oxidative damages by increasing antioxidant enzyme activities (superoxide dismutase 'SOD', catalase 'CAT', and peroxidase 'POD') and preserving chloroplast structure. Lipid peroxidation, electrolyte loss and free non-radical H2O2 formation in the chloroplast were noticeably reduced compared to the control, but chlorophyll content and photosynthetic oxygen evolution were increased. Nutrient uptake, auxin and cytokinin levels were also improved with the reduced abscisic acid levels. The results indicated that ALA and EBL could reduce the accumulation of reactive oxygen species and maintain the stability of the chloroplast membrane structure under drought stress. This study suggests that the use of ALA or EBL at 30 mg·L-1 can promote the growth, productivity and fruit quality of drought-stressed banana plants.

Effect of COVID-19 on the Cardiothoracic and Vascular Surgery Procedures Mix at a Tertiary Care Hospital.

Objective To assess the effect of the COVID-19 pandemic on the cardiothoracic and vascular surgery procedures volume at a tertiary care hospital. Materials & Methods This cross-sectional retrospective study was carried out at a tertiary care hospital's Cardiothoracic and Vascular Surgery department. All the four-year surgical procedures data were reviewed from August 2017 to August 2021. After extracting data from the hospital database software, a databank was generated in SPSS version 24.0. Average cases per month were calculated, and the data were stratified into three groups, Pre-COVID, COVID, and Post-COVID. Tables and charts were generated for the representation of data. Results The total number of patients that underwent cardiovascular and thoracic procedures during the years 2017-2021 were 3,624, with male predominance (71.5%). Procedures were divided into Pre-COVID (68.5%), COVID (15.2%) and Post-COVID (16.3%) groups. Coronary Artery Bypass Grafting (CABG) was the most common procedure throughout the study duration (56.8%) and during the COVID-19 pandemic (29 procedures/month). Congenital Heart Surgeries (16.6%) and Valvular surgeries (11.5%) were next on the list. However, congenital heart surgeries were most affected during the pandemic (16 to 5 procedures/month). The average number of surgeries per month peaked at 2017 (135 procedures/month) and after that declined to its low of 46/month during the COVID-19 pandemic (The year 2020). Conclusion Cardiothoracic and Vascular Surgeries have significantly decreased during the COVID-19 pandemic, especially the Coronary Artery Bypass (CABG) and Congenital Heart Surgeries. CABG procedures, however, remained the highest performed surgery even during the pandemic due to their emergent nature. Thoracic, vascular, and combined surgeries have stayed almost constant. The year 2020 (COVID-19 year) saw the lowest number of surgeries performed per month. An uprising trend in the number of surgical procedures is seen in the post-pandemic time (2021).

The sensory and flavor characteristics of Shaoxing Huangjiu (Chinese rice wine) were significantly influenced by micro-oxygen and electric field.

In order to improve the high cost of equipment and difficult management caused by the natural aging of Chinese rice wine (Huangjiu), micro-oxygen (MO) and electric field (PEF) technology are used to accelerate the aging of Huangjiu. The results showed that micro-oxygen and electric field have a significant effect on the sensory characteristics and flavor characteristics of Huangjiu. Compared with the naturally aged Huangjiu, the flavor compounds of Huangjiu treated with micro-oxygen and electric field increase significantly. Based on principal component analysis, Huangjiu processed at 0.35 mg L/day or 0.5 mg L/day combined electric field exhibited similar flavor to the natural aged Huangjiu, which was highly associated with long-chain fatty acid ethyl esters (C13-C18). Moreover, partial least squares regression demonstrated that sensory attributes of cereal aroma and astringency were highlighted after aging time, while fruit aroma, continuation, and full body were dominant after micro-oxygen and electric field treatment. Micro-oxygen and electric field effectively enhanced the quality of Huangjiu, which could be applied in other alcoholic beverages.

Correlations between allocation to foliar phosphorus fractions and maintenance of photosynthetic integrity in six mangrove populations as affected by chilling.

Chilling restrains the distribution of mangroves. We tested whether foliar phosphorus (P) fractions and gene expression are associated with cold tolerance in mangrove species. We exposed seedlings of six mangrove populations from different latitudes to favorable, chilling and recovery treatments, and measured their foliar P concentrations and fractions, photochemistry, nighttime respiration, and gene expression. A Kandelia obovata (KO; 26.45°N) population completely and a Bruguiera gymnorhiza (Guangxi) (BGG; 21.50°N) population partially (30%) survived chilling. Avicennia marina (24.29°N), and other B. gymnorhiza (26.66°N, 24.40°N, and 19.62°N) populations died after chilling. Photosystems of KO and photosystem I of BGG were least injured. During chilling, leaf P fractions, except nucleic acid P in three populations, declined and photoinhibition and nighttime respiration increased in all populations, with the greatest impact in B. gymnorhiza. Leaf nucleic acid P was positively correlated with photochemical efficiency during recovery and nighttime respiration across populations for each treatment. Relatively high concentrations of nucleic acid P and metabolite P were associated with stronger chilling tolerance in KO. Bruguiera gymnorhiza exhibited relatively low concentrations of organic P in favorable and chilling conditions, but its partially survived population showed stronger compensation in nucleic acid P and Pi concentrations and gene expression during recovery.

Effect of Concomitant Tricuspid Annuloplasty on Early Outcomes of Mitral Valve Replacement: A Study on Rheumatic Heart Disease Patients.

Introduction Mitral valve abnormalities in rheumatic heart disease commonly lead to functional tricuspid regurgitation. Tricuspid annuloplasty (TA) is often performed in these cases along with mitral valve replacement (MVR). Our aim was to compare the perioperative morbidity and mortality among those patients that underwent mitral valve replacement with tricuspid annuloplasty versus those that underwent isolated mitral valve replacement. Methods A retrospective analysis of 158 patients that underwent mitral valve replacement, with or without tricuspid annuloplasty, secondary to rheumatic heart disease between January 2017 and August 2020. Patients who underwent additional cardiothoracic surgical procedures (aortic valve replacement and coronary artery bypass grafting) were excluded to reduce confounders. Results The study group consisted of 158 patients (mean age 41; 73 male, 85 female) that underwent MVR with TA (n=22; 13.9%) or without TA (n=136; 86.1%). Both groups had similar comorbidity frequencies and medication history. Preoperative echocardiography showed a comparable degree of pulmonary hypertension and ejection fraction between the two groups. The TA+MVR group had similar intraoperative (81.8% vs 66.9%; p=0.161) and postoperative (45.5% vs 45.6%; p=0.991) blood products usage compared to the MVR only group. Concurrent TA resulted in similar in-hospital mortality (4.5% vs 4.4%; p=0.977) as well as early postoperative complications, namely, prolonged ICU stay (13.6% vs 10.3%; p=0.639), prolonged ventilation (0 vs 2.2%; p=0.482), re-intubation (9.1% vs 2.9%; p= 0.161), and reopening for bleeding tamponade (0 vs 5.1%; p=0.276). Conclusions TA concurrently with MVR does not appear to increase in-hospital mortality or early postoperative complications.

To determine the frequency of stroke and common factors leading to it after coronary artery bypass grafting.

OBJECTIVE: To determine the frequency of stroke and common factors leading to it after coronary artery bypass grafting. METHODS: This study was conducted at Cardiothoracic Surgery Department, Rehman Medical Institute, Peshawar. Study design was descriptive cross sectional study and the duration of the study was six months. The total sample size was 183 cases using 8.3% frequency of stroke after coronary artery bypass grafting, 95% confidence interval, 4% margin of error, using WHO sample size calculator. RESULTS: In this study mean age was 45 years with SD ± 1.26. Seventy five percent patients were male while 46(25%) females. Six patients (3%) patients had stroke while 177(97%) patients did not have any stroke. Among the six patients who were analyzed, all of them had Diabetes Mellitus and 50% patients had recent AMI, while only one patient had prior history of Atrial Fibrillation. CONCLUSIONS: Diabetes Mellitus is an independent risk factor for stroke after CABG surgery. whereas, recent MI is also associated with increased incidence of stroke in post CABG patients.

Pulmonary Hypertension as a Predictor of Early Outcomes of Mitral Valve Replacement: A Study in Rheumatic Heart Disease Patients.

Aim Mitral valve pathology in rheumatic heart disease patients is a common cause of secondary pulmonary hypertension (PH). Our aim was to evaluate pulmonary hypertension severity as a predictor of in-hospital mortality and early complications following mitral valve replacement. Methods A retrospective review of rheumatic heart disease patients who underwent mitral valve replacement between January 2017 and August 2020 was performed. Systolic pulmonary artery pressure (sPAP) was used to classify patients as no PH (<35 mmHg), mild PH (35-44 mmHg), moderate PH (45-59 mmHg) or severe PH (>60 mmHg). Patients subjected to additional cardiac procedures (such as aortic valve replacement and coronary artery bypass grafting) were excluded from the study sample. Results The study group was composed of 159 patients (mean age: 40; 73 male, 86 female) categorized as no PH (n = 32; 20.1%), mild PH (n = 14; 8.8%), moderate PH (n = 65, 40.9%) and severe PH (n = 48, 30.2%) groups. Patient demographic data and preoperative comorbidities were comparable among the four groups. Use of intraoperative and postoperative blood products was similar in all the groups. Severe PH patients had similar in-hospital mortality (4.2%; p = 0.74) as in groups with lesser degrees of pulmonary hypertension. Likewise, increasing severity of pulmonary hypertension did not confer any significant increase in early postoperative complications, namely prolonged ICU stay (10.4%; p = 0.41), prolonged ventilation (2.1%; p = 0.70), reintubation (4.2%; p = 0.90), reopening for bleeding tamponade (6.3%; p = 0.39), new-onset renal failure (6.3%; p = 0.91), postoperative stroke (4.2%; p = 0.52) or prolonged length of stay (mean: 5.6 + 2.8 days; p = 0.49). Conclusions Increasing severity of pulmonary hypertension does not appear to have a significant impact on in-hospital mortality or early postoperative outcomes of patients undergoing mitral valve replacement.

Characteristics, morbidity and mortality factors associated with Intra-Aortic Balloon Pump in Coronary Artery Bypass Graft Surgery patients.

OBJECTIVE: The aim of our study is to analyze the characteristics, morbidity and mortality of patients requiring an Intra-Aortic Balloon Pump (IABP) in Coronary Artery Bypass Grafting (CABG). METHODS: An analysis was done on the prospectively collected data of 1216 patients who had CABG in our center between July, 2017 and May, 2019 at our hospital. We categorized patients in to an IABP and non-IABP group on the basis of IABP use. We then compared the pre-operative, per-operative and post-operative characteristics of the two groups. We further stratified the patients according to pre-op ejection fraction (EF). RESULTS: Out of 1216 patients, 135(11.10%) patients required an IABP. 70(51.9%) patients of IABP group and 699(64.7%) patients of non-IABP group had hypertension (p-value 0.0036). 23.0% had previous myocardial infarction (MI) in the IABP group and 13.8% had prior myocardial infarction (MI) in non-IABP group (p-value 0.0463). Among the patients requiring an IABP, 21(15.5%) of patients had normal EF (>50%) (P-value<0.0001), 72 (53.3%) had EF 35-50%, and 41(30.3%) patients had EF<35% (p-value <0.0001). Mortality of IABP group (19.3%) was greater than non-IABP group (2.4%) (P-value 0.00001). CONCLUSIONS: Use of IABP increased as the EF decreased. Rate of post-operative stroke, prolonged ICU stay, prolonged ventilation, re-opening due to bleeding and mortality was seen to be significantly higher in the IABP group.

Foliar application of nanoparticles mitigates the chilling effect on photosynthesis and photoprotection in sugarcane.

Chilling is one of the main abiotic stresses that adversely affect the productivity of sugarcane, in marginal tropical regions where chilling incidence occurs with seasonal changes. However, nanoparticles (NPs) have been tested as a mitigation strategy against diverse abiotic stresses. In this study, NPs such as silicon dioxide (nSiO2; 5-15 nm), zinc oxide (nZnO; <100 nm), selenium (nSe; 100 mesh), graphene (graphene nanoribbons [GNRs] alkyl functionalized; 2-15 µm × 40-250 nm) were applied as foliar sprays on sugarcane leaves to understand the amelioration effect of NPs against negative impact of chilling stress on photosynthesis and photoprotection. To this end, seedlings of moderately chilling tolerant sugarcane variety Guitang 49 was used for current study and spilt plot was used as statistical design. The changes in the level chilling tolerance after the application of NPs on Guitang 49 were compared with tolerance level of chilling tolerant variety Guitang 28. NPs treatments reduced the adverse effects of chilling by maintaining the maximum photochemical efficiency of PSII (Fv/Fm), maximum photo-oxidizable PSI (Pm), and photosynthetic gas exchange. Furthermore, application of NPs increased the content of light harvesting pigments (chlorophylls and cartinoids) in NPs treated seedlings. Higher carotenoid accumulation in leaves of NPs treated seedlings enhanced the nonphotochemical quenching (NPQ) of PSII. Among the NPs, nSiO2 showed higher amelioration effects and it can be used alone or in combination with other NPs to mitigate chilling stress in sugarcane.

Delivery Room Quality Improvement Project Improved Compliance with Best Practices for a Community NICU.

A Quality Improvement bundle was implemented with the goal of standardizing the multidisciplinary approach to delivery room management. We used a Pre-Post Quality Improvement initiative with the following aims: (1) Placement of a functioning pulse oximeter by two minutes after birth, (2) Delayed intubation, (3) Normothermia on Neonatal Intensive Care Unit Admission, (4) Use of a pre-brief, debrief, and delivery room checklist. Data was collected for 548 infants, which represents every admission to the Palomar Rady Children's Hospital Neonatal Intensive Care Unit during the 35 month study period from January 1, 2010 to November 30, 2012. The intervention began on May 1, 2011. The objective of increasing the frequency of each goal was met. A significant decrease in rates of retinopathy of prematurity in our post-intervention group was found. Odds ratio 0.00 (0.000, 0.696) p = 0.008. However, this was not confirmed in the multivariable analysis so should be interpreted with caution. This quality improvement project had a positive effect on newborn resuscitation at Palomar Medical Center.

Inadvertent Methylergonovine Administration to a Neonate.

BACKGROUND Methylergonovine is an ergot alkaloid used to treat post-partum hemorrhage secondary to uterine atony. Mistaking methylergonovine for vitamin K with accidental administration to the neonate is a rare iatrogenic illness occurring almost exclusively in the delivery room setting. Complications of ergot alkaloids in neonates include respiratory depression, seizures, and death. CASE REPORT A term infant was inadvertently given 0.1 mg of methylergonovine intramuscularly in the right thigh. The error was only noted when the vial of medication was scanned, after administration, identifying it as methylergonovine rather than vitamin K. The local poison center was notified, and the infant was transferred to the neonatal intensive care unit for observation. Two hours after transfer, the infant was noted to have oxygen desaturations and required oxygen via nasal cannula. Supplemental oxygen was continued for 4 hours until the neonate was able to maintain normal oxygen saturations in room air. Feeding was started by 10 hours of life, and the infant was discharged home in good condition after a 72-hour stay without further complications. CONCLUSIONS Because of the potential for serious adverse events, vigilance is required to prevent accidental administration of methylergonovine to the neonate as a result of possible confusion with vitamin K in the early post-partum period.

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues.

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists.

Enzymatic properties of Populus α- and ß-NAD-ME recombinant proteins.

Plant mitochondrial NAD-malic enzyme (NAD-ME), which is composed of α- and ß-subunits in many species, participates in many plant biosynthetic pathways and in plant respiratory metabolism. However, little is known about the properties of woody plant NAD-MEs. In this study, we analyzed four NAD-ME genes (PtNAD-ME1 through PtNAD-ME4) in the genome of Populus trichocarpa. PtNAD-ME1 and -2 encode putative α-subunits, while PtNAD-ME3 and -4 encode putative ß-subunits. The Populus NAD-MEs were expressed in Escherichia coli cells as GST-tagged fusion proteins. Each recombinant GST-PtNAD-ME protein was purified to near homogeneity by glutathione-Sepharose 4B affinity chromatography. Milligram quantities of each native protein were obtained from 1 L bacterial cultures after cleavage of the GST tag. Analysis of the enzymatic properties of these proteins in vitro indicated that α-NAD-MEs are more active than ß-NAD-MEs and that α- and ß-NAD-MEs presented different kinetic properties (Vmax, kcat and kcat/Km). The effect of different amounts of metabolites on the activities of Populus α- and ß-NAD-MEs was assessed in vitro. While none of the metabolites evaluated in our assays activated Populus NAD-ME, oxalacetate and citrate inhibited all α- and ß-NAD-MEs and glucose-6-P and fructose inhibited only the α-NAD-MEs.

Identification and expression analysis of two small heat shock protein cDNAs from developing seeds of biodiesel feedstock plant Jatropha curcas.

Plant small heat shock proteins (sHSPs) are known to be important for environmental stress tolerance and involved in various developmental processes. In this study, two full-length cDNAs encoding sHSPs, designated JcHSP-1 and JcHSP-2, were identified and characterized from developing seeds of a promising biodiesel feedstock plant Jatropha curcas by expressed sequence tag (EST) sequencing of embryo cDNA libraries and rapid amplification of cDNA ends (RACE). JcHSP-1 and JcHSP-2 contained open-reading frames encoding sHSPs of 219 and 157 amino acids, with predicted molecular weights of 24.42kDa and 18.02kDa, respectively. Sequence alignment indicated that both JcHSP-1 and JcHSP-2 shared high similarity with other plant sHSPs. Real-time quantitative RT-PCR analysis showed that the transcriptional level of both JcHSP-1 and JcHSP-2 increased along with natural dehydration process during seed development. A sharp increase of JcHSP-2 transcripts occurred in response to water content dropping from 42% in mature seeds to 12% in dry seeds. Western blot analysis revealed that the accumulation profile of two cross-reacting proteins, whose molecular weight corresponding to the calculated size of JcHSP-1 and JcHSP-2, respectively, was well consistent with the mRNA expression pattern of JcHSP-1 and JcHSP-2 in jatropha seeds during maturation and natural dehydration. These results indicated that both JcHSPs might play an important role in cell protection and seed development during maturation of J. curcas seeds.