Transcriptome Analysis of Pyrus betulaefolia Seedling Root Responses to Short-Term Potassium Deficiency.

Potassium (K) plays a crucial role in multiple physiological and developmental processes in plants. Its deficiency is a common abiotic stress that inhibits plant growth and reduces crop productivity. A better understanding of the mechanisms involved in plant responses to low K could help to improve the efficiency of K use in plants. However, such responses remain poorly characterized in fruit tree species such as pears (Pyrus sp). We analyzed the physiological and transcriptome responses of a commonly used pear rootstock, Pyrus betulaefolia, to K-deficiency stress (0 mM). Potassium deprivation resulted in apparent changes in root morphology, with short-term low-K stress resulting in rapidly enhanced root growth. Transcriptome analyses indicated that the root transcriptome was coordinately altered within 6 h after K deprivation, a process that continued until 15 d after treatment. Potassium deprivation resulted in the enhanced expression (up to 5-fold) of a putative high-affinity K+ transporter, PbHAK5 (Pbr037826.1), suggesting the up-regulation of mechanisms associated with K+ acquisition. The enhanced root growth in response to K-deficiency stress was associated with a rapid and sustained decrease in the expression of a transcription factor, PbMYB44 (Pbr015309.1), potentially involved in mediating auxin responses, and the increased expression of multiple genes associated with regulating root growth. The concentrations of several phytohormones including indoleacetic acid (IAA), ABA, ETH, gibberellin (GA3), and jasmonic acid (JA) were higher in response to K deprivation. Furthermore, genes coding for enzymes associated with carbon metabolism such as SORBITOL DEHYDROGENASE (SDH) and SUCROSE SYNTHASE (SUS) displayed greatly enhanced expression in the roots under K deprivation, presumably indicating enhanced metabolism to meet the increased energy demands for growth and K+ acquisition. Together, these data suggest that K deprivation in P. betulaefolia results in the rapid re-programming of the transcriptome to enhance root growth and K+ acquisition. These data provide key insights into the molecular basis for understanding low-K-tolerance mechanisms in pears and in other related fruit trees and identifying potential candidates that warrant further analyses.

Successful treatment of a patient with ventriculoperitoneal shunt-associated meningitis caused by extended-spectrum ß-lactamase-producing Klebsiella pneumoniae.

Bacterial meningitis is responsible for significant morbidity and mortality worldwide, despite that modern antibiotics effectively penetrate cerebrospinal fluid to eradicate bacteria. A clinical suspicion of bacterial meningitis should be recognized early for the rapid diagnostic workup. Bacterial meningitis associated with ventriculoperitoneal shunt (VPS) is not uncommon and infrequently presents as abdominal symptoms and signs. Infections of the central nervous system caused by extended-spectrum ß-lactamase-producing Klebsiella pneumoniae (ESBL-KP) are extremely rare, and such multiple drug-resistant pathogens frequently cause inappropriate treatments and mortality. ß-Lactamases are bacterial enzymes that inactivate ß-lactam antimicrobial agents. The increased prevalence of ESBL-producing organism infections has become a worldwide problem. Timely and appropriate treatment is important to reduce mortality and morbidity of infections caused by ESBL-producing organisms. Here, we report a 61-year-old male patient who underwent VPS implantation for consequent hydrocephalus following spontaneous intracranial hemorrhage six months before this presentation. He was admitted for intermittent fever and right lower quadrant abdominal pain, and he was initially managed as acute appendicitis with its typical presentation. Finally, he was diagnosed VPS-associated meningitis caused by ESBL-KP. This patient was successfully treated with the combination of meropenem, a carbapenem antibiotic that is the drug of choice for treating ESBL-producing organisms, and high-dose fosfomycin, a phosphonic acid derivative antibiotic that is effective in treating some drug-resistant pathogens. In the present report, we emphasize the clinical presentations of catheter-related meningitis and risk factors for infections caused by ESBL-producing pathogens. Antibiotic combination therapy can provide synergistic effect and maximize anti-bacterial activity in ESBL-KP meningitis.

Efficient potassium (K) recycling and root carbon (C) metabolism improve K use efficiency in pear rootstock genotypes.

To investigate K absorption and transport mechanisms by which pear rootstock genotypes respond to low-K stress, seedlings of a potassium-efficient pear rootstock, Pyrus ussuriensis, and a potassium-sensitive rootstock, Pyrus betulifolia, were supplied with different K concentrations in solution culture. Significant differences in the absorption rate, Vmax and Km between the genotypes indicate that P. ussuriensis acclimatizes more readily to low-K stress by regulating its absorption and internal cycling. We also found that the K content in the leaves of P. betulifolia was significantly lower than that of P. ussuriensis, and the proportion of K that was returned to root from shoot, relative to K that was transported from root to shoot, was greater in P. ussuriensis, which suggests that P. ussuriensis more efficiently recycles and reuses K. When the transcriptomes of the two genotypes were compared, we found that photosynthetic genes such as CABs (Chlorophyll a/b-binding proteins), Lhcbs (Photosystem II-related proteins), and Psas (Photosystem Ⅰ associated proteins) displayed lower expression in leaves of P. betulifolia under no-K conditions, but not in P. ussuriensis. However, in the root of P. ussuriensis, carbon metabolism-related genes SS (Sucrose Synthase), HK (HexoKinase) and SDH (Sorbitol Dehydrogenase) and components of the TCA cycle (Tricarboxylic Acid cycle) were differentially expressed, indicating that changes in C metabolism may provide energy for increased K+ cycling in these plants, thereby allowing it to better adapt to the low-K environment. In addition, exogenous supply of various sugars to the roots influenced K+ influx, supporting the conclusion that sugar metabolism in roots significantly affects K+ absorption in pear.

Integrating network pharmacological and experimental models to investigate the therapeutic effects of baicalein in glaucoma.

BACKGROUND: Traditional Chinese medicine (TCM) has a long history of treating glaucoma with remarkable effects, but there is no clear conclusion on its mechanism. METHODS: Network pharmacology and molecular docking were used to analyze the mechanism and targets of TCM in the treatment of glaucoma, and baicalein was used to treat chronic ocular hypertension animal models rats for observation. RESULTS: The results of animal experiments showed that baicalein could significantly reduce intraocular pressure (IOP) in a rat model of chronic ocular hypertension and protect the structure of the retina and optic nerve, as shown by hematoxylin-eosin (H&E) staining and transmission electron microscopy (TEM). Reducing the apoptosis of retinal ganglion cells (RGCs) by upregulating the expression of the antiapoptotic protein BCL-2 is basically consistent with the results of molecular docking. In the network pharmacology analysis, many key proteins of biological pathways involved in the herbal therapeutic processes in glaucoma, such as threonine kinase 1 (AKT1, core protein of PI3K/AKT signaling), tumor protein p53 (TP53, a tumor suppressor gene coding tumor protein P53), signal transducer and activator of transcription 3 (STAT3, core protein of JAK/STAT signaling), interleukin 6 (IL-6) and interleukin 17 (IL-17, proinflammatory factors), were identified. Their interactions built complicated chain reactions in the process of glaucoma. CONCLUSION: By combining the analysis of network pharmacology and animal experimental results, baicalein could effectively improve the symptoms of glaucoma and reduce RGC apoptosis, suggesting that the potential mechanism of TCM in treating glaucoma is related to regulating inflammation and cellular immunity and reducing apoptosis.

A large-area luminescent downshifting layer containing an Eu3+ complex for crystalline silicon solar cells.

The spectral mismatch between the distribution of sunlight (AM1.5G) and crystalline silicon (c-Si) solar cells is one of the most important limiting factors of the conversion efficiency of photovoltaic (PV) devices. As an effective solution, the use of the luminescence down-shifting (LDS) technique is an important way to improve the short-wavelength response of a solar cell by shifting high-energy photons to the visible range. Herein, a large-area (17 × 17 cm2) luminescent thin film consisting of a ternary europium (Eu3+) complex and polyvinyl alcohol (PVA) was successfully constructed through a solution casting method and further developed as an effective LDS layer to improve the photoelectric conversion efficiency of c-Si solar cells with a large active area (235 cm2). The self-standing LDS layer is flexible, transparent and easily attachable to the surface of the solar cell module. Compared with the uncoated c-Si solar cell, the one coated with the LDS layer displayed an enhancement of ∼15% in external quantum efficiency (EQE) due to the high luminescence quantum yield of the Eu3+ complex doped inside the layer. These results demonstrate that use of a large area luminescent film embedding an Eu3+ complex is a versatile and effective strategy to improve the conversion efficiency of large size PV devices, giving rise to its great potential application as an LDS material.

Comparisons between patients with trimethoprim-sulfamethoxazole-susceptible and trimethoprim-sulfamethoxazole-resistant Stenotrophomonas maltophilia monomicrobial bacteremia: A 10-year retrospective study.

BACKGROUND/PURPOSE: The impact of bacteremia due to the resistance of Stenotrophomonas maltophilia to trimethoprim-sulfamethoxazole (TMP-SXT) is uncertain. This study compared the clinical characteristics and outcomes of patients with TMP-SXT-susceptible (TSSSM) and TMP-SXT-resistant S. maltophilia (TSRSM) monomicrobial bacteremia. METHODS: The medical records of adult patients with TSSSM and TSRSM monomicrobial bacteremia from January 2004 to December 2013 were reviewed and classified into two groups, namely, TSSSM and TSRSM. RESULTS: There were 184 patients with monomicrobial S. maltophilia bacteremia. The mean age was 68.3 years. Most patients were males (72.8%), had high Charlson Comorbidity Index scores, previously prescribed antimicrobial agents, and indwelling medical devices. The 14-day and in-hospital mortality rates were 23.9% and 47.2%, respectively. There were 128 patients (69.6%) with TSSSM and 56 (30.4%) with TSRSM. The incidence of TSSSM bacteremia increased during the study period. The TSSSM and TSRSM groups had similar demographic and clinical characteristics and no significant differences in 14-day and in-hospital mortality (24.2% vs. 23.2%, p = 0.833; 50.0% vs. 41.1%, p = 0.264, respectively). Patients with TSSSM bacteremia had an increased risk of septic shock (p = 0.044) and neutropenia (p = 0.028) at bacteremia onset. Logistic regression analysis indicated that acquisition of TMP-SXT resistance was an independent risk factor for prolonged hospitalization (p = 0.018) and catheter-related S. maltophilia bacteremia was inversely associated with prolonged hospitalization after bacteremia (p = 0.032). CONCLUSION: There were no significant differences in mortality for patients with TSSSM and TSRSM bacteremia, but patients with TSRSM bacteremia were associated with prolonged hospitalization after bacteremia onset.

Clinical efficacy and safety of primary antifungal prophylaxis with posaconazole versus fluconazole in allogeneic blood hematopoietic stem cell transplantation recipients-A retrospective analysis of a single medical center in Taiwan.

BACKGROUND/PURPOSE: The efficacy and safety of posaconazole compared to fluconazole as antifungal prophylaxis in patients receiving allogeneic blood hematopoietic stem cell transplantation (allo-HSCT) during the early neutropenic phase without graft-versus-host disease (GVHD) was uncertain. METHODS: The medical records of allo-HSCT recipients from a single institution, who received oral fluconazole (from January 2005 to June 2011) or oral posaconazole (from June 2011 to December 2013) during the early neutropenic phase (until engraftment), were retrospectively reviewed. RESULTS: There were 52 allo-HSCT recipients, two of whom were younger than 18 years of age. Twelve cases received posaconazole and 40 cases received fluconazole as primary antifungal prophylaxis. The two groups had similar transplant characteristics, conditioning, and GVHD prophylaxis regimens. The fluconazole group had a higher risk for development of invasive fungal infections within 90 days after allo-HSCT (43% vs. 8.3%, p = 0.039). Kaplan-Meier analysis indicated that the cumulative incidence of invasive fungal infection for 90 days after allo-HSCT was higher in the fluconazole group (log rank test, p = 0.047). Early discontinuation of antifungal prophylaxis for intolerance was significantly lower in the posaconazole group (8.3% vs. 50%, p = 0.017). Both groups had similar rates of impaired liver function. CONCLUSION: Analysis of primary fungal prophylaxis during the early neutropenic phase following allo-HSCT indicated that posaconazole was more effective and was better tolerated than fluconazole. Both drugs had similar safety profiles.

Symptomatic hypercalcemia in a rabies survivor underwent hemodialysis.

Adrenal insufficiency is an uncommon and easily ignored cause among most etiologies of hypercalcemia because not all cases of adrenal insufficiency presented with hypercalcemia. In most cases of adrenal insufficiency, viral encephalitis-related panhypopituitarism is a rare complication that is sporadically encountered in previous studies. However, this complication has never been reported in rabies encephalitis because of the extremely high rate of mortality. Rapid recovery from hypercalcemia state after glucocorticoid supplement is a direct hint of adrenal insufficiency related hypercalcemia.

Methicillin-resistant Staphylococcus aureus bacteremia in hemodialysis and nondialysis patients.

BACKGROUND/PURPOSE: Increased mortality has been reported in patients treated with vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia with high minimum inhibitory concentration (MIC) values within the susceptibility range. However, this finding has not been verified in hemodialysis patients, who have much higher invasive MRSA infection rates than nondialysis patients. We aimed at comparing vancomycin MICs between hemodialysis and nondialysis patients, and identifying predictors of high vancomycin MICs and infection-related mortality in hemodialysis patients with MRSA bacteremia. METHODS: Patients with MRSA bacteremia from January 2008 through December 2009 were enrolled. Vancomycin MIC was determined for each first isolate using the Etest method. Clinical characteristics and vancomycin MICs were compared between hemodialysis and nondialysis patients. Factors associated with high vancomycin MIC (2 µg/mL) and infection-related mortality in hemodialysis patients were analyzed. RESULTS: A total of 162 MRSA bacteremia episodes were identified. Forty-four (27.0%) isolates were obtained from hemodialysis patients and 118 (73.0%) from nondialysis patients. Diabetes (63.3% vs. 39.8%, p = 0.007) and prior vancomycin exposure in 30 days (31.8% vs. 12.7%, p = 0.005) were more prevalent in hemodialysis group than in nondialysis group. A higher prevalence of vancomycin MIC of 2 µg/mL was observed in hemodialysis group in comparison with nondialysis group (11.4% vs. 1.7%, p = 0.016). In following analyses of hemodialysis group, patients with initial presentation of septic shock had a higher risk of vancomycin MIC of 2 µg/mL than nonseptic shock patients (100.0% vs. 38.5% p = 0.014). Infection-related mortality was associated with age, Acute Physiology and Chronic Health Evaluation II (APACHE-II) score >15, presence of septic shock, receipt of mechanical ventilation, and failure to remove source of bacteremia in univariate analysis. CONCLUSION: Hemodialysis patients with MRSA bacteremia are more likely to have a high vancomycin MIC (2 µg/mL) compared with nondialysis patients. Infection-related mortality is associated with the patient's clinical manifestations, including age, APACHE-II score >15, presence of septic shock, receipt of mechanical ventilation, and failure to remove source of bacteremia. Treatment selection should be tailored according to the patient's clinical condition.

Chryseobacterium indologenes peritonitis in a patient with malignant ascites.

Chryseobacterium indologenes is an uncommon pathogen of human disease and is usually associated with indwelling devices or immunocompromised hosts. We report here an unusual case of C. indologenes peritonitis in an oncological patient with malignant ascites. The patient was treated successfully by trimethoprim-sulfamethoxazole without removal of the catheter.