Construction of an early differentiation diagnosis model for patients with severe fever with thrombocytopenia syndrome and hemorrhagic fever with renal syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with a high mortality rate. Differentiating between SFTS and hemorrhagic fever with renal syndrome (HFRS) is difficult and inefficient. Retrospective analysis of the medical records of individuals with SFTS and HFRS was performed. Clinical and laboratory data were compared, and a diagnostic model was developed based on multivariate logistic regression analyzes. Receiver operating characteristic curve analysis was used to evaluate the diagnostic model. Among the 189 patients, 113 with SFTS and 76 with HFRS were enrolled. Univariate analysis revealed that more than 20 variables were significantly associated with SFTS. Multivariate logistic regression analysis revealed that gender, especially female gender (odds ratio [OR]: 4.299; 95% confidence interval [CI]: 1.163-15.887; p = 0.029), age ≥65 years (OR: 16.386; 95% CI: 3.043-88.245; p = 0.001), neurological symptoms (OR: 12.312; 95% CI: 1.638-92.530; p = 0.015), leukopenia (<4.0 × 109/L) (OR: 17.355; 95% CI: 3.920-76.839; p < 0.001), and normal Cr (OR: 97.678; 95% CI: 15.483-616.226; p < 0.001) were significantly associated with SFTS but not with HFRS. The area under the curve of the differential diagnostic model was 0.960 (95% CI: 0.936-0.984), which was significantly better than that of each single factor. In addition, the model exhibited very excellent sensitivity and specificity (92.9% and 85.5%, respectively). In cases where HFRS and SFTS are endemic, a diagnostic model based on five parameters, such as gender, age ≥65 years, neurological symptoms, leukopenia and normal Cr, will facilitate the differential diagnosis of SFTS and HFRS in medical institutions, especially in primary care settings.

Difference in hematocrit and plasma albumin levels as an early biomarker of severity and prognosis in patients with severe fever and thrombocytopenia syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) is a widespread infectious disease with high mortality. Hence, identifying valuable biomarkers for detecting the early changes in SFTS is crucial. In this study, we investigated the relationship between the difference in hematocrit (HCT) and serum albumin (ALB) levels (HCT-ALB) and the prognosis of patients with SFTS virus infection. After excluding the patients who did not meet the SFTS diagnostic criteria, those with SFTS from the First Affiliated Hospital of Wannan Medical College were divided into a fatal and Nonfatal group based on their disease prognosis. A dynamic analysis of the daily laboratory data was conducted for 14 days following SFTS onset. A receiver operating characteristic (ROC) curve was used to evaluate the predictive value of HCT-ALB. Another sample of patients with SFTS admitted to the First Affiliated Hospital of Nanjing Medical University was utilized to verify the study conclusions. A total of 158 patients with SFTS were included. Among them, 126 patients were categorized in the Nonfatal group and 32 in the fatal group, leading to a mortality rate of 20.25% (32/158). Univariate analysis of the laboratory test findings and ROC curve analysis showed that alanine aminotransferase (ALT), aspartate aminotransferase (AST), HCT-ALB, and lactate dehydrogenase (LDH) had a relatively better ability to discriminate the disease condition of the patients with SFTS. Moreover, HCT-ALB served as a predictor of SFTS prognosis. Additionally, an area under the ROC curve (AUC) of 0.777 and a critical HCT-ALB value of 4.75 on day 7 were associated with a sensitivity of 83.3% and a specificity of 73.9%. On day 8 (AUC = 0.882), the critical value of HCT-ALB was 9.25, while the sensitivity was 100% and specificity was 76.5%. Further verification based on the data of 91 patients with SFTS admitted to the First Affiliated Hospital of Nanjing Medical University demonstrated a mortality rate of 51% (24/47) among those with HCT-ALB values >4.75 on day 7 of the disease course, highlighting the potential of the HCT-ALB value of >4.75 for predicting SFTS prognosis. High HCT-ALB values are closely related to the mortality of patients with SFTS. HCT-ALB is a sensitive and independent predictor of early disease in patients with SFTS.

Prevalence and impact of viral myocarditis in patients with severe fever with thrombocytopenia syndrome.

To explore the association and impact between viral myocarditis and mortality in patients with severe fever with thrombocytopenia syndrome. A dynamic analysis was conducted between fatal group and nonfatal group regarding the daily epidemiology data, clinical symptoms, and electrocardiogram (ECG), echocardiogram, and laboratory findings. Outcomes of patients with and without viral myocarditis were compared. The association between viral myocarditis and mortality was analyzed. Among 183 severe fever with thrombocytopenia syndrome patients, 32 were in the fatal group and 151 in the nonfatal group; there were 26 (81.25%) with viral myocarditis in the fatal group, 66 (43.70%) with viral myocarditis in the nonfatal group (p < 0.001), 79.35% of patients had abnormal ECG results. The abnormal rate of ECG in the fatal group was 100%, and in the nonfatal group was 74.83%. Univariate analysis found that the number of risk factors gradually increased on Day 7 of the disease course and reached the peak on Day 10. Combined with the dynamic analysis of the disease course, alanine aminotransferase, aspartate aminotransferase, creatine kinase, creatine kinase fraction, lactate dehydrogenase, hydroxybutyrate dehydrogenase, neutrophil count, serum creatinine, Na, Ca, carbon dioxide combining power, amylase, lipase, activated partial thromboplastin time and thrombin time had statistically significant impact on prognosis. The incidence of fever with thrombocytopenia syndrome combined with viral myocarditis is high, especially in the fatal group of patients. Viral myocarditis is closely related to prognosis and is an early risk factor. The time point for changes in myocarditis is Day 7 of the course of the disease.

Asymmetric Assembly and Self-Adjuvanted Antigen Delivery Platform for Improved Antigen Uptake and Antitumor Effect.

The development of effective tumor vaccines is an important direction in the field of cancer prevention/immunotherapy. Efficient antigen delivery is essential for inducing effective antitumor responses for tumor vaccines. Lumazine synthase (BLS) from Brucella spp. is a decameric protein with delivery and adjuvant properties, but its application in tumor vaccines is limited. Here, we developed an antigen delivery platform by combining a BLS asymmetric assembly and the Plug-and-Display system of SpyCatcher/SpyTag. An asymmetric assembly system consisting of BLSke and BLSdr was developed to equally assemble two molecules. Then, the MHC-I-restricted ovalbumin peptide (OVA(257-264) SIINFEKL) was conjugated with BLSke, and a cell-penetrating peptide (CPP) KALA was conjugated with BLSdr using the SpyCatcher/SpyTag system. KALA modification enhanced internalization of OVA peptides by DCs as well as promoted the maturation of DCs and the cross-presentation of SIINFEKL. Moreover, the immunotherapy of a KALA-modified vaccine suppressed tumor growth and enhanced CD8+ T cell responses in E.G7-OVA tumor-bearing mice. In the prophylactic model, KALA-modified vaccination showed the most significant protective effect and significantly prolonged the survival period of tumor challenged mice. In conclusion, the asymmetric assembly platform equally assembles two proteins or peptides, avoiding their spatial or functional interference. This asymmetric assembly and Plug-and-Display technology provide a universal platform for rapid development of personalized tumor vaccines.

Using Defect Control To Break the Stability-Activity Trade-Off in Enzyme Immobilization via Competitive Coordination.

Immobilization of enzymes within metal-organic frameworks is a powerful strategy to enhance the long-term usability of labile enzymes. However, the thus-confined enzymes suffer from the trade-off between enhanced stability and reduced activity because of the contradiction between the high crystallinity and the low accessibility. Here, by taking laccase and zeolitic imidazolate framework-8 (ZIF-8) as prototypes, we disclosed an observation that the stability-activity trade-off could be solved by controlling the defects via competitive coordination. Owing to the presence of competitive coordination between laccase and the ligand precursor of ZIF-8, there existed a three-stage process in the de novo encapsulation: nucleation-crystallization-recrystallization. Our results show that the biocomposites collected before the occurrence of recrystallization possessed both increased activity and enhanced stability. The findings here shed new light on the control of defects through the subtle use of competitive coordination, which is of great significance for the engineering application of biomacromolecules.

Destabilizing Effects of Environmental Stressors on Aquatic Communities and Interaction Networks across a Major River Basin.

Human-driven environmental stressors are increasingly threatening species survival and diversity of river systems worldwide. However, it remains unclear how the stressors affect the stability changes across aquatic multiple communities. Here, we used environmental DNA (eDNA) data sets from a human-dominated river in China over 3 years and analyzed the stability changes in multiple communities under persistent anthropogenic stressors, including land use and pollutants. First, we found that persistent stressors significantly reduced multifaceted species diversity (e.g., species richness, Shannon's diversity, and Simpson's diversity) and species stability but increased species synchrony across multiple communities. Second, the structures of interaction networks inferred from an empirical meta-food web were significantly changed under persistent stressors, for example, resulting in decreased network modularity and negative/positive cohesion. Third, piecewise structural equation modeling proved that the persistent stress-induced decline in the stability of multiple communities mainly depended upon diversity-mediated pathways rather than the direct effects of stress per se; specifically, the increase of species synchrony and the decline of interaction network modularity were the main biotic drivers of stability variation. Overall, our study highlights the destabilizing effects of persistent stressors on multiple communities as well as the mechanistic dependencies, mainly through reducing species diversity, increasing species synchrony, and changing interaction networks.

Vaccination with a Brucella ghost developed through a double inactivation strategy provides protection in Guinea pigs and cattle.

Vaccination can prevent and control animal brucellosis. Currently, live attenuated vaccines are extensively used to prevent Brucella infection. However, traditional vaccines such as live attenuated vaccines are associated with biological safety risks for both humans and animals. The bacterial ghost (BG) is a new form of vaccine with great prospects. However, bacterial cells cannot be completely inactivated by biological lysis, conferring a safety risk associated with the vaccine. In this study, we developed a Brucella abortus A19 bacterial ghost (A19BG) through a double inactivation strategy with sequential biological lysis and hydrogen peroxide treatment. This strategy resulted in 100% inactivation of Brucella, such that viable bacterial cells were not detected even at an ultrahigh concentration of 1010 colony-forming units/mL. Furthermore, A19BG had a typical BG morphology and good genetic stability. Moreover, it did not induce adverse reactions in guinea pigs. The levels of antibodies, interferon-γ, interleukin-4, and CD4+ T cells in guinea pigs inoculated with the A19BG vaccine were similar to those inoculated with the existing A19 vaccine. Immunization with A19BG conferred a similar level of protection with that of A19 against Brucella melitensis M28 in both guinea pigs and cattle. In conclusion, the combination of biological lysis and H2O2-mediated inactivation is a safe and effective strategy that can serve as a reference for the preparation of BG vaccines.

Intermittent urethral infusion of dimethylsulfoxide for urethral amyloidosis: a case report and literature review.

Urethral amyloidosis (UA) is a very rare condition. We here report the case of a 63-year-old male patient who was admitted to our outpatient department due to aggravating dysuria, frequent urination, pain during intercourse, and a gradually enlarging mass at the ostium of his urethra, which he first notice one year earlier. Pathological tissue biopsy of urethral ostium mass confirmed UA. Intermittent urethra infusion of dimethyl sulfoxide was performed and the treatment effect is satisfactory.

Fluorescence temperature sensing of NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ nanoparticles at low and high temperatures.

NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+upconversion nanoparticles were prepared using a solvothermal method, and the effects of key factors such as the content of sensitiser Nd3+and Yb3+on their luminescence properties were investigated. The nanoparticles are homogeneous in size and well dispersed. Under 808 nm excitation, it can produce strong upconversion fluorescence. At the same time, the nanoparticles have good temperature sensing properties at the thermally coupled energy levels of 700 and 646 nm for Tm3+. Using its fluorescence intensity ratio, accurate temperature measurements can be performed, and it has been found that it exhibits different temperature sensing properties in low and high-temperature regions. The maximum relative sensitivity was found to be 0.88% K-1and 1.89% K-1for the low-temperature region of 285-345 K and the high-temperature region of 345-495 K. The nanoparticles were applied to the internal temperature measurement of lithium batteries and the actual high-temperature environment, respectively, and were found to have good temperature measurement performance.

A neutrophil-to-lymphocyte ratio-based prognostic model to predict mortality in patients with HBV-related acute-on-chronic liver failure.

BACKGROUND: Although the Asian Pacific Association for the Study of the Liver acute-on-chronic liver failure (ACLF) research consortium (AARC) ACLF score is easy to use in patients with hepatitis b virus-related ACLF (HBV-ACLF), serum lactate is not routinely tested in primary hospitals, and its value may be affected by some interference factors. Neutrophil-to-lymphocyte ratio (NLR) is used to assess the status of bacterial infection (BI) or outcomes in patients with various diseases. We developed an NLR-based AARC ACLF score and compared it with the existing model. METHODS: A total of 494 HBV-ACLF patients, enrolled in four tertiary academic hospitals in China with 90-day follow-up, were analysed. Prognostic performance of baseline NLR and lactate were compared between cirrhotic and non-cirrhotic subgroups via the receiver operating curve and Kaplan-Meier analyses. A modified AARC ACLF (mAARC ACLF) score using NLR as a replacement for lactate was developed (n = 290) and validated (n = 204). RESULTS: There were significantly higher baseline values of NLR in non-survivors, patients with admission BI, and those with higher grades of ACLF compared with the control groups. Compared with lactate, NLR better reflected BI status in the cirrhotic subgroup, and was more significantly correlated with CTP, MELD, MELD-Na, and the AARC score. NLR was an independent predictor of 90-day mortality, and was categorized into three risk grades (< 3.10, 3.10-4.78, and > 4.78) with 90-day cumulative mortalities of 8%, 21.2%, and 77.5% in the derivation cohort, respectively. The mAARC ACLF score, using the three grades of NLR instead of corresponding levels of lactate, was superior to the other four scores in predicting 90-day mortality in the derivation (AUROC 0.906, 95% CI 0.872-0.940, average P < 0.001) and validation cohorts (AUROC 0.913, 95% CI 0.876-0.950, average P < 0.01), with a considerable performance in predicting 28-day mortality in the two cohorts. CONCLUSIONS: The prognostic value of NLR is superior to that of lactate in predicting short-term mortality risk in cirrhotic and non-cirrhotic patients with HBV-ACLF. NLR can be incorporated into the AARC ACLF scoring system for improving its prognostic accuracy and facilitating the management guidance in patients with HBV-ACLF in primary hospitals.

eDNA metabarcoding revealed differential structures of aquatic communities in a dynamic freshwater ecosystem shaped by habitat heterogeneity.

Freshwater ecosystems have been threatened by complicated disturbances from both natural and anthropogenic variables, especially in dynamic and complex river basins. The environmental DNA (eDNA)-based approach provides a broader spectrum and higher throughput way of biomonitoring for biodiversity assessment compared with traditional morphological survey. Most eDNA metabarcoding studies have been limited to a few specific taxa/groups and habitat scopes. Here we applied the eDNA metabarcoding to characterize the structures and spatial variations of zooplankton and fish communities among different habitat types in a highly dynamic and complex freshwater ecosystem of the Daqing River basin (DRB). The results showed that varied species spectra of zooplankton and fish communities were identified and unique dominant species occurred across habitats. Additionally, markedly spatial distributions of biotic community structures were observed in areas with different habitat characteristics. Natural variables, including geographic distances and gradient ratio, as well as anthropogenic factors of chemical oxygen demand (COD) and organic chemicals demonstrated significant effects but different outcomes on the structures of zooplankton and fish communities. Moreover, the relative abundances of specific aquatic taxa were associated with the gradient of particular environmental variables. This case study verified the distribution patterns and differentiation mechanisms of biotic communities under habitat heterogeneity could be captured by application of eDNA biomonitoring. And habitat-specific and even species-specific environmental stressors would be diagnosed for improving management of complex river basins.

Clinical Treatment Experience in Severe and Critical COVID-19.

Compared with other deadly diseases, the coronavirus disease 2019 (COVID-19) is highly infectious with a relatively low mortality rate. Although critical cases account for only 5% of cases, the mortality rate for the same is nearly 50%. Therefore, the key to the COVID-19 treatment is to effectively treat severe patients and reduce the transition from severe to critical cases. A retrospective study was carried out to evaluate outcomes of treatment in patients with severe and critical COVID-19 admitted to a COVID-19 special hospital in Wuhan, China. A total of 75 severe and critical COVID-19 patients were admitted and treated with immunomodulation as the main strategy combined with anti-inflammatory therapy and appropriate anticoagulation. Leukocyte levels in patients with 7-14 days of onset to diagnosis were significantly lower than in those with >14 days. Higher levels of globulin and D-dimer and lower lymphocyte levels were found in the older age group (>65 years) than in the middle-aged group (50-64 years). Patients with comorbidity had higher levels of inflammatory indicators. After treatment, 65 (86.67%) patients were cured, 7 (9.33%) had improved, and 3 (4.00%) had died. Median hospitalization duration was 23 days. Fatal cases showed continuously increased levels of globulin, dehydrogenase (LDH), hypersensitive C-reactive protein (hs-CRP), D-dimer, and cytokines during treatment. Time from onset to diagnosis, age, and comorbidity are important influencing factors on treatment effects. The occurrence of immunosuppression, "cytokine storm," and thrombosis may be an important cause of death in severely infected cases. In conclusion, high cure rate and low mortality suggested that immunomodulation combined with anti-inflammatory therapy and appropriate anticoagulant therapy is a good strategy for treatment of patients with severe and critical COVID-19.

Autophagy inhibition by reversine and its suppressive effects on human hepatocellular carcinoma cells.

INTRODUCTION: Therapy for human hepatocellular carcinoma (HCC) remains a great challenge for physicians and patients worldwide. The anti-tumor effects of reversine have attracted much more concerns. MATERIALS AND METHODS: This study evaluated the growth regulatory effects of reversine on HCC cells lines. Meanwhile, the underlying mechanism including autophagy modulation was also identified. RESULTS: reversine markedly inhibited the proliferation of both HCC cells and induced cell apoptosis and multinuclear in a dose-dependent manner. In addition, the decreased ratio of LC3II/LC3I as well as elevated p62 expression were observed under reversine treatment, indicating the autophagy inhibition by reversine in HepG2 cell line. Moreover, modulation of autophagy with rapamycin and chloroquine significantly attenuated and enhanced the cytostatic effects of reversine, respectively. CONCLUSIONS: reversine could reduce the cell viability of HCC cells via inducing cell apoptosis and polyploidy. In addition, cell autophagy was involved and might play a protective role in HCC cells, the joint use of autophagy inhibitor enhanced reversine-mediating antitumor effects. Our data offered novel ideas for comprehensive therapeutic regimes on human hepatocellular carcinoma.

A report of clinical diagnosis and treatment of nine cases of coronavirus disease 2019.

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 has become an important public health issue in the world. More than 118 000 cases were confirmed around the world. The main clinical manifestations were respiratory symptoms and occasional gastrointestinal symptoms. However, there is no unified standard for the diagnosis and treatment of COVID-19. In the retrospective analysis, we report nine cases of COVID-19, describe the history of contact, clinical manifestations, the course of diagnosis and clinical treatment before, during and after treatment.

Human activities' fingerprint on multitrophic biodiversity and ecosystem functions across a major river catchment in China.

Human-induced global change dramatically alters individual aspects of river biodiversity, such as taxonomic, phylogenetic or functional diversity, and is predicted to lead to losses of associated ecosystem functions. Understanding these losses and dependencies are critical to human well-being. Until now, however, most studies have only looked either at individual organismal groups or single functions, and little is known on the effect of human activities on multitrophic biodiversity and on ecosystem multifunctionality in riverine ecosystem. Here we profiled biodiversity from bacteria to invertebrates based on environmental DNA (hereafter, 'eDNA') samples across a major river catchment in China, and analysed their dependencies with multiple ecosystem functions, especially linked to C/N/P-cycling. Firstly, we found a spatial cross-taxon congruence pattern of communities' structure in the network of the Shaying river, which was related to strong environmental filtering due to human land use. Secondly, human land use explained the decline of multitrophic and multifaceted biodiversity and ecosystem functions, but increased functional redundancy in the riverine ecosystem. Thirdly, biodiversity and ecosystem function relationships at an integrative level showed a concave-up (non-saturating) shape. Finally, structural equation modeling suggested that land use affects ecosystem functions through biodiversity-mediated pathways, including biodiversity loss and altered community interdependence in multitrophic groups. Our study highlights the value of a complete and inclusive assessment of biodiversity and ecosystem functions for an integrated land-use management of riverine ecosystems.

Endovascular Treatment for Cavernous Carotid Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Coiling and flow diversion are established endovascular techniques for treatment of cavernous carotid aneurysms (CCAs). We performed a systematic review of published series on endovascular treatment of CCAs in order to assess the efficacy and safety between coiling and flow diversion. METHODS: We conducted a computerized search of PubMed, MEDLINE, and Web of Science electronic databases for reports on endovascular treatment of CCAs from 1990 to 2019. Comparisons were made in complete occlusion rate, improvement of symptoms rate and intraoperative complication rate between coiling and flow diversion. RESULTS: Fourteen studies with 736 patients were included in this systematic review. Five hundred ninety-4 patients underwent coiling, 142 patients underwent flow diversion. The complete occlusion rate in the coiling group was significantly lower than that in the flow division group (odds ratio .37, 95%CI .16-.83, P < .00001), a forest plot did not reveal any significant differences in the improvement of symptoms rate or intraoperative complication rate following coiling and flow diversion. Complete occlusion rate was significantly lower in the coiling group (53%, 95%CI .40-.67) compared with the flow diversion group (74%, 95%CI .55-.94). Improvement of symptoms was significantly lower in the coiling group (54%, 95%CI .46-.63) compared with the flow diversion group (92%, 95%CI .85-.99). Coiling group had lower intraoperative complication rate (9%, 95%CI .06-.12) compared with flow division group (36%, 95%CI .25-.47). CONCLUSIONS: Compared with coiling, the use of flow diversion for the treatment of CCAs may increase complete occlusion rate, and improvement of symptoms rate, but it also raised intraoperative complication rate. Due to the lack of high quality control research, further randomized controlled trials are needed to verify our conclusions.

Genome-wide comparison reveals divergence of cassava and rubber aquaporin family genes after the recent whole-genome duplication.

BACKGROUND: Aquaporins (AQPs) are a class of integral membrane proteins that facilitate the passive transport of water and other small solutes across biological membranes. Despite their importance, little information is available in cassava (Manihot esculenta), a perennial shrub of the Euphorbiaceae family that serves the sixth major staple crop in the world. RESULTS: This study presents a genome-wide analysis of the AQP gene family in cassava. The family of 42 members in this species could be divided into five subfamilies based on phylogenetic analysis, i.e., 14 plasma membrane intrinsic proteins (PIPs), 13 tonoplast intrinsic proteins (TIPs), nine NOD26-like intrinsic proteins (NIPs), four X intrinsic proteins (XIPs), and two small basic intrinsic proteins (SIPs). Best-reciprocal-hit-based sequence comparison and synteny analysis revealed 34 orthologous groups (OGs) present in the Euphorbiaceae ancestor, and nearly one-to-one or two-to-one orthologous relationships were observed between cassava with rubber/physic nut, reflecting the occurrence of one so-called ρ recent whole-genome duplication (WGD) in the last common ancestor of cassava and rubber. In contrast to a predominant role of the ρ WGD on family expansion in rubber, cassava AQP duplicates were derived from the WGD as well as local duplication. Species-specific gene loss was also observed in cassava, which includes the entire NIP4 group and/or six OGs. Comparison of conserved motifs and gene expression profiles revealed divergence of paralogs in cassava as observed in rubber. CONCLUSIONS: Our findings will not only improve our knowledge on family evolution in Euphorbiaceae, but also provide valuable information for further functional analysis of AQP genes in cassava and rubber.

Characterization of a vacuolar sucrose transporter, HbSUT5, from Hevea brasiliensis: involvement in latex production through regulation of intracellular sucrose transport in the bark and laticifers.

BACKGROUND: Sucrose (Suc), as the precursor molecule for rubber biosynthesis in Hevea brasiliensis, is transported via phloem-mediated long-distance transport from leaves to laticifers in trunk bark, where latex (cytoplasm of laticifers) is tapped for rubber. In our previous report, six Suc transporter (SUT) genes have been cloned in Hevea tree, among which HbSUT3 is verified to play an active role in Suc loading to the laticifers. In this study, another latex-abundant SUT isoform, HbSUT5, with expressions only inferior to HbSUT3 was characterized especially for its roles in latex production. RESULTS: Both phylogenetic analysis and subcellular localization identify HbSUT5 as a tonoplast-localized SUT protein under the SUT4-clade (=type III). Suc uptake assay in baker's yeast reveals HbSUT5 to be a typical Suc-H+ symporter, but its high affinity for Suc (Km = 2.03 mM at pH 5.5) and the similar efficiency in transporting both Suc and maltose making it a peculiar SUT under the SUT4-clade. At the transcript level, HbSUT5 is abundantly and preferentially expressed in Hevea barks. The transcripts of HbSUT5 are conspicuously decreased both in Hevea latex and bark by two yield-stimulating treatments of tapping and ethephon, the patterns of which are contrary to HbSUT3. Under the ethephon treatment, the Suc level in latex cytosol decreases significantly, but that in latex lutoids (polydispersed vacuoles) changes little, suggesting a role of the decreased HbSUT5 expression in Suc compartmentalization in the lutoids and thus enhancing the Suc sink strength in laticifers. CONCLUSIONS: Our findings provide insights into the roles of a vacuolar sucrose transporter, HbSUT5, in Suc exchange between lutoids and cytosol in rubber-producing laticifers.