The processed C-terminus of AvrRps4 effector suppresses plant immunity via targeting multiple WRKYs.

Pathogens generate and secrete effector proteins to the host plant cells during pathogenesis to promote virulence and colonization. If the plant carries resistance (R) proteins that recognize pathogen effectors, effector-triggered immunity (ETI) is activated, resulting in a robust immune response and hypersensitive response (HR). The bipartite effector AvrRps4 from Pseudomonas syringae pv. pisi has been well studied in terms of avirulence function. In planta, AvrRps4 is processed into two parts. The C-terminal fragment of AvrRps4 (AvrRps4C) induces HR in turnip and is recognized by the paired resistance proteins AtRRS1/AtRPS4 in Arabidopsis. Here, we show that AvrRps4C targets a group of Arabidopsis WRKY, including WRKY46, WRKY53, WRKY54, and WRKY70, to induce its virulence function. Indeed, AvrRps4C suppresses the general binding and transcriptional activities of immune-positive regulator WRKY54 and WRKY54-mediated resistance. AvrRps4C interferes with WRKY54's binding activity to target gene SARD1 in vitro, suggesting WRKY54 is sequestered from the SARD1 promoter by AvrRps4C. Through the interaction of AvrRps4C with four WRKYs, AvrRps4 enhances the formation of homo-/heterotypic complexes of four WRKYs and sequesters them in the cytoplasm, thus inhibiting their function in plant immunity. Together, our results provide a detailed virulence mechanism of AvrRps4 through its C-terminus.

A Survey of Pharmacists and Other Healthcare Professionals in Vietnam: Factors Influencing Knowledge and Attitudes Toward Reporting Adverse Drug Reactions.

Background: Knowledge and attitudes of healthcare professionals are significant factors that affect the reporting of adverse drug reactions (ADRs). No previous research has examined the predictors of knowledge and attitudes toward ADR reporting in Vietnam. Objectives: The aim of this study was to examine the factors (ie, demographic and job-related characteristics) associated with inadequate knowledge and negative attitudes toward ADR reporting in a Vietnamese public hospital. Methods: A survey recruited a cross-sectional sample of 511 healthcare professionals (with a response rate of 92.9%) at a public hospital in Vinh Long province, Vietnam, from December 2022 to February 2023, using a self-administered questionnaire. Factors related to knowledge and attitudes toward ADR reporting were identified using univariate and multivariate logistic regression. Results: Pharmacists had significantly lower knowledge scores (mean = 5.86) than medical practitioners (7.24) and nurses (6.72). Additionally, pharmacists' attitudes scored significantly lower (34.61) than those of medical practitioners (37.21) and nurses (36.86). Multivariate logistic regression showed that educational level, healthcare profession, monthly on-call shifts, and number of direct patient interactions were factors associated with a lower level of knowledge regarding ADR reporting. Additionally, age group and healthcare profession were identified as factors associated with negative attitudes toward ADR reporting among healthcare workers. Conclusions: Our study identified several factors associated with lower levels of knowledge and negative attitudes toward ADR reporting among healthcare workers in Vietnam. These findings highlight the need for targeted interventions and education programs to improve healthcare workers' knowledge and attitudes toward ADR reporting.

The physiological role of thiol-based redox sensors in plant defense signaling.

Plants have developed multilayered defense strategies to adapt and acclimate to the kaleidoscopic environmental changes that rapidly produce reactive oxygen species (ROS) and induce redox changes. Thiol-based redox sensors containing the redox-sensitive cysteine residues act as the central machinery in plant defense signaling. Here, we review recent research on thiol-based redox sensors in plants, which perceive the changes in intracellular H2 O2 levels and activate specific downstream defense signaling. The review mainly focuses on the molecular mechanism of how the thiol sensors recognize internal/external stresses and respond to them by demonstrating several instances, such as cold-, drought-, salinity-, and pathogen-resistant signaling pathways. Also, we introduce another novel complex system of thiol-based redox sensors operating through the liquid-liquid phase separation.

Factors Associated With Advanced Colorectal Neoplasia in Patients With CKD.

RATIONALE & OBJECTIVE: The risk of developing colorectal cancer in patients with chronic kidney disease (CKD) is twice that of the general population, but the factors associated with colorectal cancer are poorly understood. The aim of this study was to identify factors associated with advanced colorectal neoplasia in patients with CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Patients with CKD stages 3-5, including those treated with maintenance dialysis or transplantation across 11 sites in Australia, New Zealand, Canada, and Spain, were screened for colorectal neoplasia using a fecal immunochemical test (FIT) as part of the Detecting Bowel Cancer in CKD (DETECT) Study. EXPOSURE: Baseline characteristics for patients at the time of study enrollment were ascertained, including duration of CKD, comorbidities, and medications. OUTCOME: Advanced colorectal neoplasia was identified through a 2-step verification process with colonoscopy following positive FIT and 2-year clinical follow-up for all patients. ANALYTICAL APPROACH: Potential factors associated with advanced colorectal neoplasia were explored using multivariable logistic regression. Sensitivity analyses were performed using grouped LASSO (least absolute shrinkage and selection operator) logistic regression. RESULTS: Among 1,706 patients who received FIT-based screening-791 with CKD stages 3-5 not receiving kidney replacement therapy (KRT), 418 receiving dialysis, and 497 patients with a functioning kidney transplant-117 patients (6.9%) were detected to have advanced colorectal neoplasia (54 with CKD stages 3-5 without KRT, 34 receiving dialysis, and 29 transplant recipients), including 9 colorectal cancers. The factors found to be associated with advanced colorectal neoplasia included older age (OR per year older, 1.05 [95% CI, 1.03-1.07], P<0.001), male sex (OR, 2.27 [95% CI, 1.45-3.54], P<0.001), azathioprine use (OR, 2.99 [95% CI, 1.40-6.37], P=0.005), and erythropoiesis-stimulating agent use (OR, 1.92 [95% CI, 1.22-3.03], P=0.005). Grouped LASSO logistic regression revealed similar associations between these factors and advanced colorectal neoplasia. LIMITATIONS: Unmeasured confounding factors. CONCLUSIONS: Older age, male sex, erythropoiesis-stimulating agents, and azathioprine were found to be significantly associated with advanced colorectal neoplasia in patients with CKD.

Redox-mediated structural and functional switching of C-repeat binding factors enhances plant cold tolerance.

C-repeat binding factors (CBFs) are key cold-responsive transcription factors that play pleiotropic roles in the cold acclimation, growth, and development of plants. Cold-sensitive cbf knockout mutants and cold-tolerant CBF overexpression lines exhibit abnormal phenotypes at warm temperatures, suggesting that CBF activity is precisely regulated, and a critical threshold level must be maintained for proper plant growth under normal conditions. Cold-inducible CBFs also exist in warm-climate plants but as inactive disulfide-bonded oligomers. However, upon translocation to the nucleus under a cold snap, the h2-isotype of cytosolic thioredoxin (Trx-h2), reduces the oxidized (inactive) CBF oligomers and the newly synthesized CBF monomers, thus producing reduced (active) CBF monomers. Thus, the redox-dependent structural switching and functional activation of CBFs protect plants under cold stress.

Willingness of Healthcare Students in Vietnam to Volunteer During the COVID-19 Pandemic.

Healthcare students play an important role in volunteering activity, often addressing staff shortages. However, during the COVID-19 pandemic, the willingness of students to volunteer in contribution to the pandemic response, especially in Vietnam, has not been thoroughly investigated. This study aimed to determine the prevalence of and factors associated with the willingness of healthcare students to volunteer during the COVID-19 pandemic in Vietnam. For this, an online cross-sectional survey was conducted, between June 7th and July 6th, 2021, among healthcare students from 10 fields of study at the largest public university of medicine and pharmacy in the Mekong Delta, Vietnam. Of 2032 respondents, 1473 (72.5%) reported that they would be willing to volunteer during the COVID-19 pandemic. More than half of the students reported having a desire to volunteer in non-patient contact activities such as data entry (65.9%) and logistics (57.7%). Whereas less than 50% of the participants were willing to volunteer with activities involving patients. Year of education, study field, educational format, living arrangements, health status self-perception, chronic illness possession, COVID-19 fear level, past volunteering experience in non-healthcare sectors, and COVID-19 prevention and control training course attendance were all associated with a willingness to volunteer. The strongest barriers preventing volunteering included fear for the health of their family and lack of training/knowledge. Conclusively, healthcare students reported a high level of willingness, indicating a positive attitude toward responding to the COVID-19 pandemic. Adequate training should be employed to increase the willingness among healthcare students in Vietnam.

Disulfide reductase activity of thioredoxin-h2 imparts cold tolerance in Arabidopsis.

Many thioredoxin-h (Trx-h) proteins, cytosolic isotypes of Trxs, have been functionally characterized in plants; however, the physiological function of Arabidopsis Trx-h2, which harbors two active site cysteine (Cys) residues and an N-terminal extension peptide containing a fatty acid acylation site, remains unclear. In this study, we investigated the physiological function of Trx-h2 by performing several abiotic stress treatments using trx-h1-3 knockout mutant lines, and found that the reductase function of Trx-h2 is critical for cold resistance in Arabidopsis. Plants overexpressing Trx-h2 in the trx-h2 mutant background (Trx-h2OE/trx-h2) showed strong cold tolerant phenotypes compared with Col-0 (wild type) and trx-h2 mutant plants. By contrast, Trx-h2(C/S)OE/trx-h2 plants expressing a variant Trx-h2 protein, in which both active site Cys residues were substituted by serine (Ser) residues, showed high cold sensitivity, similar to trx-h2 plants. Moreover, cold-responsive (COR) genes were highly up-regulated in Trx-h2OE/trx-h2 plants but not in trx-h2 and Trx-h2(C/S)OE/trx-h2 plants under cold conditions. These results explicitly suggest that the cytosolic Trx-h2 protein relays the external cold stress signal to downstream cold defense signaling cascades through its protein disulfide reductase function.

The CKD bowel health study: understanding the bowel health and gastrointestinal symptom management in patients with chronic kidney disease: a mixed-methods observational longitudinal study (protocol).

BACKGROUND: Gastro-intestinal (GI) intolerance is a frequently reported outcome in patients with kidney failure receiving maintenance dialysis and those who have received kidney transplants. Symptoms of GI intolerance (diarrhoea, constipation, bloating, abdominal pain, heart burn, and reflux) are associated with significant reduction in quality of life, morbidity, and increased used of healthcare resources. Having chronic kidney disease (CKD), together with related changes in diet and medication, may alter the gut microbiota and the microbial-derived uraemic metabolites that accumulate in kidney failure, and contribute to various complications including chronic diarrhoea, opportunistic infections, and drug-related colitis. Despite the high disease burden among patients with kidney replacement therapies, GI symptoms are often under-recognised and, consequently limited resources and strategies are devoted to the management of gastrointestinal complications in patients with CKD. METHODS: The CKD Bowel Health Study is a multi-centre mixed-methods observational longitudinal study to better understand the bowel health and GI symptom management in patients with CKD. The program comprises of a longitudinal study that will assess the burden and risk factors of GI intolerance in patients treated with maintenance dialysis; a semi-structured interview study that will describe experiences of GI intolerance (including symptoms, treatment, self-management) in transplant candidates and recipients; and a discrete choice experience to elicit patient preferences regarding their experiences and perspectives of various intervention strategies for the management of GI symptoms after kidney transplantation. DISCUSSION: This proposed program of work aims to define the burden the GI intolerance in patients with kidney failure and generate evidence on the patients' experiences of GI intolerance and their perspectives on their clinical and own management strategies of these symptoms, ensuring a patient-centred approach to guide clinical decision making and to inform the best study design for intervention trials. TRIAL REGISTRATION: This study is registered on the Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12621000548831 . This study has been approved by the Western Sydney Local Health District Human Research Ethics Committee of New South Wales Health (HREC ETH03007). This study is supported by a National Health and Medical Research Council (NHMRC) Australia Investigator Grant (APP1195414), and an NHMRC Australia Postgraduate Scholarship (APP2005244).

One-Time Fecal Immunochemical Screening for Advanced Colorectal Neoplasia in Patients with CKD (DETECT Study).

BACKGROUND: In patients with CKD, the risk of developing colorectal cancer is high and outcomes are poor. Screening using fecal immunochemical testing (FIT) is effective in reducing mortality from colorectal cancer, but performance characteristics of FIT in CKD are unknown. METHODS: To determine the detection rates and performance characteristics of FIT for advanced colorectal neoplasia (ACN) in patients with CKD, we used FIT to prospectively screen patients aged 35-74 years with CKD (stages 3-5 CKD, dialysis, and renal transplant) from 11 sites in Australia, New Zealand, Canada, and Spain. All participants received clinical follow-up at 2 years. We used a two-step reference standard approach to estimate disease status. RESULTS: Overall, 369 out of 1706 patients who completed FIT (21.6%) tested positive; 323 (87.5%) underwent colonoscopies. A total of 1553 (91.0%) completed follow-up; 82 (4.8%) had died and 71 (4.2%) were lost. The detection rate of ACN using FIT was 6.0% (5.6%, 7.4%, and 5.6% for stages 3-5 CKD, dialysis, and transplant). Sensitivity, specificity, and positive and negative predictive values of FIT for ACN were 0.90, 0.83, 0.30, and 0.99, respectively. Of participants who underwent colonoscopy, five (1.5%) experienced major colonoscopy-related complications, including bowel perforation and major bleeding. CONCLUSIONS: FIT appears to be an accurate screening test for patients with CKD, such that a negative test may rule out the diagnosis of colorectal cancer within 2 years. However, the risk of major complications from work-up colonoscopy are at least ten-fold higher than in the general population.

Facilitators and barriers to students' learning in an obesity prevention graduate program.

Childhood obesity is a major public health concern with underpinnings at the individual, family, community and societal levels. The Transdisciplinary Childhood Obesity Prevention Graduate Certificate Program (TOP) is an innovative graduate-level certificate program developed to train professionals to understand and address obesity from multiple perspectives using an interprofessional education (IPE) approach. Currently, there is limited knowledge on what promotes or hinders learning in IPE approaches dealing with obesity prevention. The goal of this report is to address this gap by describing facilitators and barriers to learning in a graduate-level training program. Using a qualitative research design, semi-structured interviews were collected from 23 professional students, as part of a larger program evaluation project for TOP. Thematic analysis revealed the challenges and strengths of the program that relate specifically to: its interprofessional approach, its structure, and its activities. Interprofessional exchanges were reported to expand students' learning, but adequate interprofessional representation must be maintained, and the complexity of interprofessional collaborations must also be well-coordinated. Standardising the program structure and courses for consistency across professions, and clear communication are critical to program success. Findings add to the existing literature on what promotes effective learning in a professional obesity prevention program using an IPE approach.

S-nitrosylation switches the Arabidopsis redox sensor protein, QSOX1, from an oxidoreductase to a molecular chaperone under heat stress.

The Arabidopsis quiescin sulfhydryl oxidase 1 (QSOX1) thiol-based redox sensor has been identified as a negative regulator of plant immunity. Here, we have found that small molecular weight proteins of QSOX1 were converted to high molecular weight (HMW) complexes upon exposure to heat stress and that this was accompanied by a switch in QSOX1 function from a thiol-reductase to a molecular chaperone. Plant treatment with S-nitrosoglutathione (GSNO), which causes nitrosylation of cysteine residues (S-nitrosylation), but not with H2O2, induced HMW QSOX1 complexes. Thus, functional switching of QSOX1 is induced by GSNO treatment. Accordingly, simultaneous treatment of plants with heat shock and GSNO led to a significant increase in QSOX1 chaperone activity by increasing its oligomerization. Consequently, transgenic Arabidopsis overexpressing QSOX1 (QSOX1OE) showed strong resistance to heat shock, whereas qsox1 knockout plants exhibited high sensitivity to heat stress. Plant treatment with GSNO under heat stress conditions increased their resistance to heat shock. We conclude that S-nitrosylation allows the thiol-based redox sensor, QSOX1, to respond to various external stresses in multiple ways.

A Cross-Sectional Study Investigating Clinical Features, Brain Imaging, and Treatment Efficacy in Patients with Cerebral Venous Thrombosis in the Mekong Delta, Vietnam.

Background: Cerebral venous thrombosis (CVT) is a challenging condition with potential long-term consequences, but it is also a treatable disorder that offers the possibility of complete recovery. This study was conducted to comprehensively investigate the clinical features, brain imaging findings, and treatment outcomes of patients diagnosed with cerebral venous thrombosis. Materials and Methods: Conducted as a cross-sectional descriptive study, patients diagnosed with cerebral venous thrombosis were enrolled at Can Tho Central General Hospital between January 2021 and June 2022. Results: Notably, a substantial proportion of patients (83.4%) exhibited signs of brain damage, with intracranial hemorrhage (50%), brain infarction (30.9%), subarachnoid hemorrhage (16.6%), and hemorrhagic infarct (4.7%) being the predominant findings. Thrombosis primarily affected the superior sagittal sinus (85.7%), transverse sinus (52.4%), and sigmoid sinus (42.8%). All patients received anticoagulation treatment, resulting in a favorable recovery upon hospital discharge for the majority (90.5%), while a small percentage (9.5%) experienced critical illness or death. Conclusion: Our study on cerebral venous thrombosis found diverse clinical presentations, primarily headache. Intracranial hemorrhage was common, affecting superior sagittal, transverse, and sigmoid sinuses. Most patients achieved favorable recoveries with anticoagulation treatment, emphasizing early intervention's importance.

How Do Social and Behavioral Change Interventions Respond to Social Norms to Improve Women's Diets in Low- and Middle-Income Countries? A Scoping Review.

Healthy dietary practices are highly influenced by social norms, the widely-held expectations about the behaviors that are appropriate or typical within a given group. However, many nutrition programs designed to reduce women's undernutrition in low- and middle-income countries do not address the influence of social and gender norms in their interventions, and therefore, there is limited information about how norms-responsive interventions have been designed and implemented. The objective of this scoping review was to identify and describe social and behavioral change interventions designed to improve women's dietary practices and nutritional intake that integrate the influence of social and gender norms. We systematically searched 4 databases (Scopus, Web of Science, PubMed, and CINAHL) for peer-reviewed articles describing design, implementation, and/or assessment of nutrition interventions in low- or middle-income countries. Results are reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Our review identified 27 articles from 25 projects or research studies that addressed social or gender norms related to women's dietary practices. The majority focused on the pregnancy and lactation periods, and a few aimed to reach all women of reproductive age. Interventions most often endeavored to shift norms through multiple activities, channels, and platforms, aiming to reach not only the primary participants but also influencers and reference groups. Intervention approaches ranged from home visits and support groups to engage influential family members to community-level outreach with opinion leaders such as religious leaders, health care workers, and peer change agents. Most interventions were delivered through the health sector or were community-based, with some nutrition-sensitive agriculture interventions. There is increasing, although still limited, integration of social and gender norms perspectives in the design, implementation, and assessment of interventions to improve women's diets. This comprehensive review summarizes influential norms and intervention approaches, an important step toward enhancing the effectiveness of social and behavioral change interventions by addressing nutrition-relevant norms. This study was registered at Open Science Framework as JSBF7.

Dengue virus serotypes and related factors in children with dengue hemorrhagic fever in Southern Vietnam.

INTRODUCTION: After the Coronavirus Disease 2019 pandemic, a high number of cases and severe dengue in children were reported in some provinces in the south of Vietnam. This study aimed to determine the distribution of dengue virus serotypes and their correlation with demographic factors, disease severity, clinical manifestations, and laboratory findings. METHODOLOGY: This study employed a cross-sectional design. Ninety-six dengue-infected children admitted to Can Tho Children's Hospital between October 2022 and March 2023 were included. Confirmation of dengue infection was achieved through the real-time polymerase chain reaction (RT-PCR). RESULTS: Among the identified serotypes, DENV-2 accounted for the highest proportion (71.87%), followed by DENV-1 (23.96%), and DENV-4 (4.17%). DENV-3 was not detected. No significant demographic, disease severity, or laboratory differences were observed among the identified dengue serotypes. However, DENV-2 was associated with a higher occurrence of mucous membrane hemorrhages and gastrointestinal bleeding compared to other serotypes. CONCLUSIONS: Although DENV-2 was the most prevalent serotype responsible for dengue in children in southern Vietnam, it did not lead to more severe cases compared to other serotypes. This finding is crucial for evaluating the illness's prognosis.

BM-BronchoLC - A rich bronchoscopy dataset for anatomical landmarks and lung cancer lesion recognition.

Flexible bronchoscopy has revolutionized respiratory disease diagnosis. It offers direct visualization and detection of airway abnormalities, including lung cancer lesions. Accurate identification of airway lesions during flexible bronchoscopy plays an important role in the lung cancer diagnosis. The application of artificial intelligence (AI) aims to support physicians in recognizing anatomical landmarks and lung cancer lesions within bronchoscopic imagery. This work described the development of BM-BronchoLC, a rich bronchoscopy dataset encompassing 106 lung cancer and 102 non-lung cancer patients. The dataset incorporates detailed localization and categorical annotations for both anatomical landmarks and lesions, meticulously conducted by senior doctors at Bach Mai Hospital, Vietnam. To assess the dataset's quality, we evaluate two prevalent AI backbone models, namely UNet++ and ESFPNet, on the image segmentation and classification tasks with single-task and multi-task learning paradigms. We present BM-BronchoLC as a reference dataset in developing AI models to assist diagnostic accuracy for anatomical landmarks and lung cancer lesions in bronchoscopy data.

Development and application of a second-generation multilingual tool for invasion risk screening of non-native terrestrial plants.

Under the increasing threat to native ecosystems posed by non-native species invasions, there is an urgent need for decision support tools that can more effectively identify non-native species likely to become invasive. As part of the screening (first step) component in non-native species risk analysis, decision support tools have been developed for aquatic and terrestrial organisms. Amongst these tools is the Weed Risk Assessment (WRA) for screening non-native plants. The WRA has provided the foundations for developing the first-generation WRA-type Invasiveness Screening Kit (ISK) tools applicable to a range of aquatic species, and more recently for the second-generation ISK tools applicable to all aquatic organisms (including plants) and terrestrial animals. Given the most extensive usage of the latter toolkits, this study describes the development and application of the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). As a second-generation ISK tool, the TPS-ISK is a multilingual turnkey application that provides several advantages relative to the WRA: (i) compliance with the minimum standards against which a protocol should be evaluated for invasion process and management approaches; (ii) enhanced questionnaire comprehensiveness including a climate change component; (iii) provision of a level of confidence; (iv) error-free computation of risk scores; (v) multilingual support; (vi) possibility for across-study comparisons of screening outcomes; (vii) a powerful graphical user interface; (viii) seamless software deployment and accessibility with improved data exchange. The TPS-ISK successfully risk-ranked five representative sample species for the main taxonomic groups supported by the tool and ten angiosperms previously screened with the WRA for Turkey. The almost 20-year continuous development and evolution of the ISK tools, as opposed to the WRA, closely meet the increasing demand by scientists and decision-makers for a reliable, comprehensive, updatable and easily deployable decision support tool. For terrestrial plant screening, these requirements are therefore met by the newly developed TPS-ISK.

Patient Preferences for the Management of Gastrointestinal Symptoms in Kidney Transplantation: a Discrete Choice Experiment.

Introduction: Gastrointestinal (GI) symptoms in kidney transplant are common and debilitating. We aimed to ascertain patients' preferences for GI symptom management options to help future interventions align with treatment priorities. Methods: A discrete choice experiment was conducted with kidney transplant recipients in 3 Australian nephrology units. A multinomial logit model was used to quantify the preferences and trade-offs between 5 characteristics: cost, formulation, symptom burden, dietary changes, and medication quantities. Results: Seventy patients participated (mean age ± SD: 47 ± 15 years, 56% female), 57% had GI symptoms. Patients preferred interventions that will achieve complete resolution of GI symptoms compared to no improvement (odds ratio [95% confidence interval]: 15.3 [1.80, 129.50]), were delivered as a tablet rather than a sachet (1.6 [1.27, 2.08]), retained their current diet compared to eliminating food groups (6.0 [2.19, 16.27]), reduced medication burden (1.4 [1.06, 1.79]), and had lower costs (0.98 [0.96, 1.00]). Participants would be willing to pay AUD$142.20 [$83.90, $200.40] monthly to achieve complete resolution of GI symptoms or AUD$100.90 [$9.60, $192.10] to have moderate improvement in symptoms. Conclusions: Interventions that are highly effective in relieving all GI symptoms without the need for substantive dietary changes, and in tablet form, are most preferred by kidney transplant recipients.

Thiol-Surface-Engineered Cellulose Nanocrystals in Favor of Copper Ion Uptake.

Cellulose, the most abundant natural polymer on earth, has recently gained attention for a large spectrum of applications. At a nanoscale, nanocelluloses (mainly involving cellulose nanocrystals or cellulose nanofibrils) possess many predominant features, such as highly thermal and mechanical stability, renewability, biodegradability and non-toxicity. More importantly, the surface modification of such nanocelluloses can be efficiently obtained based on the native surface hydroxyl groups, acting as metal ions chelators. Taking into account this fact, in the present work, the sequential process involving chemical hydrolysis of cellulose and autocatalytic esterification using thioglycolic acid was performed to obtain thiol-functionalized cellulose nanocrystals. The change in chemical compositions was attributed to thiol-functionalized groups and explored via the degree of substitution using a back titration method, X-ray powder diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis. Cellulose nanocrystals were spherical in shape and ca. 50 nm in diameter as observed via transmission electron microscopy. The adsorption behavior of such a nanomaterial toward divalent copper ions from an aqueous solution was also assessed via isotherm and kinetic studies, elucidating a chemisorption mechanism (ion exchange, metal chelation and electrostatic force) and processing its operational parameters. In contrast to an inactive configure of unmodified cellulose, the maximum adsorption capacity of thiol-functionalized cellulose nanocrystals toward divalent copper ions from an aqueous solution was 4.244 mg g-1 at a pH of 5 and at room temperature.

Chemical constituents of Desmodium triflorum and their antifungal activity against various phytopathogenic fungi.

In the course of finding new antifungal natural compounds against plant pathogens, the methanol extract of Desmodium triflorum was investigated phytochemically. From n-butanol-soluble fraction, seven compounds (1-7) were isolated and structurally elucidated. Of which, six compounds belong to flavone 6- or 8-C-glycoside class (1-6). Three major compounds (1-3) exhibited moderate in vitro antifungal activity against Sclerotium rolfsii, Fusarium oxysporum f. sp. cubense, and Phytophthora palmivora. Compound 1 (IC50 = 162.1 µg/mL) was most active against S. rolfsii in a dose-dependent manner. At 300 µg/mL, compounds 1 and 2 significantly inhibited P. palmivora, whereas compound 3 lacked effectiveness. In addition, the nanoemulsion of the methanol extract with a droplet size of 12.2 nm displayed an excellent inhibition against S. rolfsii and P. palmivora compared with the normal extract. The presence of 1 (0.846%) and 2 (0.759%) in the methanol extract may attribute to the antifungal activity of D. triflorum. These results proved the potential of D. triflorum and its C-glycoside flavonoids against phytopathogenic fungi for the first time. Besides, an enhancement in the effectiveness of nanoemulsion containing D. triflorum extract against the fungi was confirmed. The structural characteristics of 1 and 2 could be considered to develop new fungicidal substances in the future.