Talaromyces Marneffei Infection in an HIV-Negative Patient in a Non-Endemic Area: a Case Report and Literature Review.

BACKGROUND: Talaromyces marneffei infection is insidious and occurs in immunocompromised or deficient populations, particularly in patients with acquired immune deficiency syndrome (AIDS). It is less commonly found in HIV-negative individuals, but is more likely to present with increased leukocytes (increased CD4+ cell counts), negative blood cultures, respiratory distress, and bone destruction. Therefore, we report a case of an HIV-negative patient infected with Talaromyces marneffei. METHODS: After percutaneous lung aspiration biopsy, infectious agent macrogenomics assay (NGS) was done. RESULTS: The patient's chest CT suggested a pulmonary infection but failed to accurately confirm the diagnosis, and a lung puncture biopsy with NGS was performed which suggested the presence of Talaromyces marneffei, and the patient was given symptomatic treatment. CONCLUSIONS: For fungal infections with non-respiratory symptoms as the first manifestation, we should clarify the infectious agent as early as possible, and it is necessary to improve chest CT in a timely manner. When blood culture cannot be clearly diagnosed, timely percutaneous lung biopsy should be performed to obtain pathological tissue and perform NGS to further clarify the condition.

Mechanized Pneumonia Secondary to Legionella Infection with Diarrhea as the First Manifestation: a Case Report.

BACKGROUND: Legionella is a Gram-negative bacterium, and Legionella pneumonia is an atypical pneumonia, clinically similar to Streptococcus pneumoniae or other bacterial pneumonia, with respiratory symptoms as the most common clinical manifestation, but very few patients have a predominantly GI symptom presentation, which often leads to delayed treatment; timely and effective standardized treatment has a good prognosis, and individual patients can develop mechanized pneumonia. Therefore, we report a case of Legionella infection with diarrhea as the first manifestation secondary to mechanized pneumonia. METHODS: bronchoscopy, percutaneous lung aspiration biopsy, infection pathogen macrogenomics next-generation assay (mNGS). RESULTS: The patient was examined by bronchoscopy and NGS was performed suggesting the presence of Legionella and poorly absorbed by the treated pulmonary lesion condition. Therefore, we further improved the pathology of percutaneous lung puncture biopsy suggesting the presence of mechanized pneumonia and gave the patient symptomatic treatment. CONCLUSIONS: For severe pneumonia with non-respiratory symptoms as the first manifestation, we need to clarify the infecting pathogen as early as possible, and we also need to evaluate the anti-infective efficacy in a timely manner. After a full course of treatment with active pathogen coverage and imaging suggesting poor absorption, bronchoscopy or percutaneous lung biopsy should be perfected in a timely manner to obtain pathological tissue to further clarify the condition.

Flexible Anti-Metal RFID Tag Antenna Based on High-Conductivity Graphene Assembly Film.

We propose a flexible anti-metal radio frequency identification (RFID) tag antenna based on a high-conductivity graphene assembly film (HCGAF). The HCGAF has a conductivity of 1.82 × 106 S m-1, a sheet resistance of 25 mΩ and a thickness of 22 µm. The HCGAF is endowed with high conductivity comparable to metal materials and superb flexibility, which is suitable for making antennas for microwave frequencies. Through proper structural design, parameter optimization, semiautomatic manufacturing and experimental measurements, an HCGAF antenna could realize a realized gain of -7.3 dBi and a radiation efficiency of 80%, and the tag could achieve a 6.4 m read range at 915 MHz on a 20 × 20 cm2 flat copper plate. In the meantime, by utilizing flexible polyethylene (PE) foam, good conformality was obtained. The read ranges of the tags attached to curved copper plates with different bending radii were measured, as well as those of those attached to several daily objects. All the results demonstrate the excellent performance of the design, which is highly favorable for practical RFID anti-metal applications.

Risk factors for cutaneous warts and the influence factors of curative effect of 5-flurouracil therapy in southern China.

BACKGROUND: To systematically explore the risk factors of cutaneous warts and influence factor for the effectiveness of 5-fluorouracil (5-FU). METHODS: This is a case-control study of 408 cutaneous warts patients and 408 controls of Chinese Han population in southern China. In addition, 244 patients who presented with an initial episode of warts without treatment were treated with intralesional 5-FU. The influence factors of 5-FU therapeutic effects were analyzed. RESULTS: After adjustment, we found age (≤14 years old), lower education attainment, alcohol intake, smoking, less daily sleeping hours, severe psychological stress, hyperhidrosis, living in house or apartment, having cutaneous warts roommates, and sharing personal items with other persons to be risk factors for warts. Importantly, physical fitness played a protective role against warts. Two hundred and twenty-seven patients in 244 (93.03%) were successfully treated with 5-FU. Multivariate analysis indicated that smoking, alcohol intake, severe psychological stress, more than six months' duration of cutaneous warts, lesions on foot and warts diameter ≥5 mm adversely affected the effectiveness of 5-FU. CONCLUSIONS: The newly identified risk factors for cutaneous warts and influence factors for efficacy of 5-FU provided clues for warts prevention and treatment of Chinese Han population.

Phenylboronic ester-modified anionic micelles for ROS-stimuli response in HeLa cell.

Smart polymers as ideal drug nanocarriers have attracted much attention due to the effective drug delivery, internalization and release once triggered by intracellular stimuli, as well as reduced cytotoxicity. We here reported the anionic micelle consisting of copolymer (PEG-b-PAsp) and a PBE (Phenylboronic Ester) group grafted, which can achieve fast response to intracellular ROS and enhanced anti-tumor activity. With this, PEG-b-PAsp-g-PBE/DOX system showed better tumor growth inhibition when studied on HeLa cell lines with high level of intracellular ROS and its subcutaneous tumor models. Additionally, the administration of PEG-b-PAsp-g-PBE/DOX did cause significantly lower systemic toxicity in comparison with free DOX. Hence, PEG-b-PAsp-g-PBE could be a highly efficient and safe nanocarrier to improve the efficacy of chemotherapeutic.

[Exploration of omics mechanism and drug prediction of coronavirus-induced heart failure based on clinical bioinformatics].

Objective: Present study investigated the mechanism of heart failure associated with coronavirus infection and predicted potential effective therapeutic drugs against heart failure associated with coronavirus infection. Methods: Coronavirus and heart failure were searched in the Gene Expression Omnibus (GEO) and omics data were selected to meet experimental requirements. Differentially expressed genes were analyzed using the Limma package in R language to screen for differentially expressed genes. The two sets of differential genes were introduced into the R language cluster Profiler package for gene ontology (GO) and Kyoto gene and genome encyclopedia (KEGG) pathway enrichment analysis. Two sets of intersections were taken. A protein interaction network was constructed for all differentially expressed genes using STRING database and core genes were screened. Finally, the apparently accurate treatment prediction platform (EpiMed) independently developed by the team was used to predict the therapeutic drug. Results: The GSE59185 coronavirus data set was searched and screened in the GEO database, and divided into wt group, ΔE group, Δ3 group, Δ5 group according to different subtypes, and compared with control group. After the difference analysis, 191 up-regulated genes and 18 down-regulated genes were defined. The GEO126062 heart failure data set was retrieved and screened from the GEO database. A total of 495 differentially expressed genes were screened, of which 165 were up-regulated and 330 were down-regulated. Correlation analysis of differentially expressed genes between coronavirus and heart failure was performed. After cross processing, there were 20 GO entries, which were mainly enriched in virus response, virus defense response, type Ⅰ interferon response, γ interferon regulation, innate immune response regulation, negative regulation of virus life cycle, replication regulation of viral genome, etc. There were 5 KEGG pathways, mainly interacting with tumor necrosis factor (TNF) signaling pathway, interleukin (IL)-17 signaling pathway, cytokine and receptor interaction, Toll-like receptor signaling pathway, human giant cells viral infection related. All differentially expressed genes were introduced into the STRING online analysis website for protein interaction network analysis, and core genes such as signal transducer and activator of transcription 3, IL-10, IL17, TNF, interferon regulatory factor 9, 2'-5'-oligoadenylate synthetase 1, mitogen-activated protein kinase 3, radical s-adenosyl methionine domain containing 2, c-x-c motif chemokine ligand 10, caspase 3 and other genes were screened. The drugs predicted by EpiMed's apparent precision treatment prediction platform for disease-drug association analysis were mainly TNF-α inhibitors, resveratrol, ritonavir, paeony, retinoic acid, forsythia, and houttuynia cordata. Conclusions: The abnormal activation of multiple inflammatory pathways may be the cause of heart failure in patients after coronavirus infection. Resveratrol, ritonavir, retinoic acid, amaranth, forsythia, houttuynia may have therapeutic effects. Future basic and clinical research is warranted to validate present results and hypothesis.

Enzymatic Synthesis of Trideuterated Sialosides.

Sialic acids are a family of acidic monosaccharides often found on the termini of cell surface proteins or lipid glycoconjugates of higher animals. Herein we describe the enzymatic synthesis of the two isotopically labeled sialic acid derivatives d3-X-Gal-α-2,3-Neu5Ac and d3-X-Gal-α-2,3-Neu5Gc. Using deuterium oxide as the reaction solvent, deuterium atoms could be successfully introduced during the enzymatic epimerization and aldol addition reactions when the sialosides were generated. NMR and mass spectrometric analyses confirmed that the resulting sialosides were indeed tri-deuterated. These compounds may be of interest as internal standards in liquid chromatography/mass spectrometric assays for biochemical or clinical studies of sialic acids. This was further exemplified by the use of this tri-deuterated sialosides as internal standards for the quantification of sialic acids in meat and egg samples.

Peptide-mediated cationic micelles drug-delivery system applied on a VEGFR3-overexpressed tumor.

Copolymers as a kind of drug delivery carrier always lack targeting efficiency. So a peptide conjugated to a drug delivery system has attracted much attention for tumor-targeted nanomedicine. Thus, we here report a conjugation compound consisting of a copolymer (PEG-b-PLL) and a peptide (Cys-Ile-Gln-Pro-Phe-Tyr-Pro, CP7). For receptor-mediated endocytosis by this peptide, the CP7-PEG-b-PLL conjugation significantly enhanced the chemotherapeutic efficacy as a potent nanocarrier compared with free DOX. The CP7-PEG-b-PLL exhibited excellent pharmacokinetic behavior via a radioactive iodine-131 (I) tracing method. With this, the CP7-PEG-b-PLL/DOX system showed better tumor growth inhibition when studied on A549 cell lines and subcutaneous tumor models, but with less toxicity than free DOX. All these results suggest that the CP7-modified drug cationic micelles could represent a novel platform for successful drug delivery toward VEGFR3-overexpressed tumors.

The Pathways for Layered Double Hydroxide Nanoparticles to Enhance Antigen (Cross)-Presentation on Immune Cells as Adjuvants for Protein Vaccines.

Nanoparticles (NPs) are intensively investigated as adjuvants in new generation vaccines, while how these NPs promote the immune responses has not been well understood. In this research, we have tried to elucidate the possible pathways for layered double hydroxide (LDH) NPs to provoke immune responses. As previously reported, LDH NPs efficiently deliver antigens to antigen presenting cells (APCs). In this research, we have found that these internalized LDH NPs are not released by these APCs within 8 h. We have for the first time found that macrophage cells exchange the internalized LDH NPs with other surrounding ones, which may promote immune responses in an additional way. Moreover, the internalized LDH-antigen NPs significantly facilitate the maturation of immature DCs and enhance cross-presentation of epitope/MHC class I complexes on the DC surface. This research would help understand the NP adjuvant mechanism and further assist the design of new specific NPs as more efficient nano-adjuvants.

De Novo Computational Design for Development of a Peptide Ligand Oriented to VEGFR-3 with High Affinity and Long Circulation.

The overexpression of VEGFR-3 is correlated with a worse prognosis in lung cancer and has been regarded as a rational target for specific drug delivery. Here, VEGFR-3 homing peptide library was efficiently established by computational design. Strong fluorescent signals of selected peptides were observed in A549 cells, but much weaker in other cells. The positive immunostaining overlapped with VEGFR-3 confirmed high affinity and selectivity of one novel peptide (CP-7). In addition, cell uptake of FITC-CP-7 peptide was significantly blocked by coinjection of excess CP-7 peptide. After labeled with 131I, the profile of pharmacology and biodistribution could be traced in vivo. The 131I-radiolabeled CP-7 peptide conjugates were >85% stable in serum over 4 h and exhibited a specific uptake of 18.04 ± 2.04% ID/g at 0.5 h after injection to high VEGFR-3 expressing A549 tumor mice. More importantly, lower uptake concentration in heart (1.06 ± 0.15% ID/g) after 2 h demonstrated the safety of peptide in vivo. The high uptake in the kidneys revealed that renal clearance was the main route of 131I-CP-7 peptide elimination from the body. Lower accumulation of 131I-CP-7 peptide in VEGFR-3 negative HeLa tumor mice further indicated that CP-7 peptide exhibited a higher tumor-homing efficiency. These studies provided a straightforward analytical access to design and screen bioactive peptide based on protein structure and revealed that CP-7 peptide represented a promising homing peptide of VEGFR-3-positive cancer in vitro and in vivo which could be used as a novel target molecule to achieve efficient drug delivery.

Diverse Profiles of AI-1 Type Quorum Sensing Molecules in Cultivable Bacteria from the Mangrove (Kandelia obovata) Rhizosphere Environment.

Mangrove rhizosphere environment harbors diverse populations of microbes, and some evidence showed that rhizobacteria behavior was regulated by quorum sensing (QS). Investigating the diverse profiles of QS molecules in mangrove ecosystems may shed light on the bacterial roles and lead to a better understanding of the symbiotic interactions between plants and microbes. The aims of the current study focus on identifying AI-1 type QS signals, i.e., acyl homoserine lactones (AHLs), in Kandelia obovata rhizosphere environment. Approximately 1200 rhizobacteria were screened and 184 strains (15.3%) tested were positive. Subsequent 16s rRNA gene sequencing and dereplication analyses identified 24 species from the positive isolates, which were affiliated to three different phyla, including Proteobacteria, Firmicutes, and Actinobacteria. Thin-layer chromatography separation of extracts revealed diverse AHL profiles and detected at least one active compound in the supernatant of these 24 cultivable AHL-producers. The active extracts from these bacterial isolates were further evaluated by ultra performance liquid chromatography-mass spectrometry, and the carbon side chain length ranged from C4 to C14. This is the first report on the diversity of AI-1 type auto-inducers in the mangrove plant K. obovata, and it is imperative to expand our knowledge of plant-bacteria interactions with respect to the maintenance of wetland ecosystem health.

An Integrative Folate-Based Metal Complex Nanotube as a Potent Antitumor Nanomedicine as Well as an Efficient Tumor-Targeted Drug Carrier.

Metal-organic complexes (MOCs) are emerging developing functional materials, the different categories of metal ions and organic biomolecules provide great possibilities for the morphologies, sizes, and properties of the products. Enlightened by the previous works of folate-nickel nanotubes (FA-Ni NTs), herein, a series of metal ions are tested to coordinate with folate (FA) by the solvothermal method, among which the folate-cobalt(II) complex is formed to be a scaffold for the nanotube with the length of 150-500 nm and inner diameter of 6-11 nm, while the other metal ions fail. In vitro experiments reveal that folate-cobalt nanotubes (FA-Co NTs) have excellent antitumor activity toward tumor cells with high expression levels of folate receptor (FR), whereas they show extremely low toxicity to normal cells. Furthermore, these kinds of NTs show better antitumor ability when the anticancer drug doxorubicin is encapsulated through cell surface receptor-mediated endocytosis. Moreover, we study the fundamental pharmacokinetic profiles and biodistribution of FA-Co NTs on mice and also prove its targeting capability to tumor tissues on tumor-bearing mice using the radioactive iodine-131 (131I) tracing method. FA-Co NTs can also markedly inhibit the growth of tumor with minimal side effects when administered individually in vivo. These findings will expand the research on FA based metal complex nanomaterials as a kind of potential antitumor nanomedicine as well as a targeted drug carrier.

The fucosidase-pool of Emticicia oligotrophica: Biochemical characterization and transfucosylation potential.

Three novel bacterial α-l-fucosidases, which cleave terminal fucosyl residues from glycoconjugates are reported in this work. Originating from the recently discovered bacterium Emticicia oligotrophica, recombinant fucosidase isoforms designated as Eo0918, Eo3066 and Eo3812 were shown to have the highest activity between pH 6.0 and 7.0 and temperature optima between 30 and 45°C. All enzymes catalyzed the hydrolysis of the model substrate pNP-α-l-fucose and revealed significantly different regiospecificities towards fucose-containing oligosaccharides: Eo0918 liberated exclusively α1,6-linked fucose and Eo3812 released only α1,3-fucosyl residues, whereas Eo3066 showed broader substrate promiscuity. The enzymatic activity of Eo0918 and Eo3812 increased upon the addition of Ca(2+), Mn(2+) and Zn(2+) ions, whereas the activity of Eo3066 was significantly decreased in the presence of these metal ions. In addition, Eo0918 also catalyzed the transfer of fucose from pNP-α-l-fucose to the 7-hydroxyl group of 4-methylumbelliferone with up to 15% transglycosylation yield. Facile recombinant expression in E. coli, distinct substrate specificities and the transglycosylation ability of Eo0918 presented herein make these newly discovered fucosidases valuable candidates for bioanalytical and biotechnological applications.

Is low anticoagulation intensity more beneficial for patients with bileaflet mechanical mitral valves? A meta-analysis.

BACKGROUND: For the mitral valve replacement (MVR) using the lowest thrombogenic risk bileaflet valves (St. Jude Medical [St Paul, MN, USA], Carbomedics [Austin, TX, USA] and On-X [Austin, TX, USA]), excellent results can be achieved by adopting the anticoagulation intensity (median INR<2.5) which is lower than the recommended intensity (INR:2.5~3.5). Our aim was to provide a pooled estimate of potential benefit from clinical studies using low anticoagulation intensity and high intensity in these patients. METHODS: Relevant studies published before February 2014 were searched through a number of digital databases (MEDLINE, EMBASE, Cochrane Library, etc.). They were pooled by SPSS19.0 using the random effect method in three fields: occurrence rate of major thromboembolism, major hemorrhage and major total events. Fourteen studies with 3595 patients were included. The follow-up period was 12,846.6 patient-years. RESULTS: Pooled estimates indicated reduction in major hemorrhage (RR:0.420, 95%CI: 0.296~0.595, P<0.001) and major total events (RR: 0.738, 95%CI: 0.604~0.902, P=0.003) in the low intensity group. No difference was noted in major thromboembolism (RR: 1.045, 95%CI: 0.814~1.341, P=0.75). CONCLUSION: Compared with the recommended high intensity, low anticoagulation intensity (median INR<2.5) may be more beneficial for the MVR patients using the lowest thrombogenic risk bileaflet valves. We recommended an INR between 2.0 and 2.5, with a median INR of 2.3 for these MVR patients.

Biochemical characterisation of the neuraminidase pool of the human gut symbiont Akkermansia muciniphila.

Since the isolation and identification of Akkermansia muciniphila one decade ago, much attention has been drawn to this gut bacterium due to its role in obesity and type 2 diabetes. This report describes the discovery and biochemical characterisation of all four putative neuraminidases annotated in the A. muciniphila genome. Recombinantly expressed candidate genes, which were designated Am0705, Am0707, Am1757 and Am2085, were shown to cover complementary pH ranges between 4.0 and 9.5. Temperature optima of the enzymes lay between 37 and 42 °C. All four enzymes were strongly inhibited by Cu(2+) and Zn(2+), and loss of activity after the addition of EDTA suggests that all neuraminidases, with the exception of Am0707, require divalent metal ions for their catalytic function. Chemoenzymatically synthesised α2,3- and α2,6-linked indoyl-sialosides were utilised to determine the regioselectivity and substrate promiscuity of the neuraminidases towards C5-modifications of sialic acids with N-acetyl-, N-glycolyl-, N-propionyl-, or hydroxyl-groups. The combination of simple purification procedures and good activities of some of the characterised neuraminidases makes them potentially interesting as tools in bioanalytical or industrial applications.

One assay for all: exploring small molecule phosphorylation using amylose-polyiodide complexes.

We present a generic method for screening small molecule kinases for their acceptor specificity. The release of the reaction byproduct adenosine diphosphate (ADP) triggers a concentration-dependent formation of amylose from sucrose, by using the combined enzymatic action of sucrose synthase and glycogen synthase. Kinase activities could be quantified photometrically after the formation of a dark-blue amylose-polyiodide complex. We demonstrate that this method can be used to profile both known and novel nucleotide- and sugar-kinases for their substrate specificity. Using a facile and widely available methodology, the amylose-polyiodide small-molecule kinase assay presented herein has the potential to perform substrate screenings of small molecule kinases in a high-throughput manner.

Severe instead of mild hyperglycemia inhibits neurogenesis in the subventricular zone of adult rats after transient focal cerebral ischemia.

Accumulated evidence suggests that enhanced neurogenesis stimulated by ischemic injury contributes to stroke outcome. However, it is unclear whether hyperglycemia, which is frequently tested positive in patients with acute ischemic stroke, influences stroke-induced neurogenesis. The aim of the present study is to examine the effect of hyperglycemia on stroke-induced neurogenesis in a rat model of transient focal cerebral ischemia. For this purpose, adult male Sprague-Dawley rats (220-250 g) were subjected to 90 min of middle cerebral artery occlusion (MCAO). Glucose was administered during ischemia to produce target blood levels ranging from 4.83 ± 0.94 mM (normoglycemia) to 20.76 ± 1.56 mM. To label proliferating cells in ischemic ipsilateral subventricular zone (SVZ) of lateral ventricles, 5'-bromo-2'-deoxyuridine (BrdU) was injected 24h after MCAO. Brains were harvested 2h post-BrdU to evaluate the effects of hyperglycemia on infarct volume and SVZ cell proliferation. Rats that were severely hyperglycemic (19.26 ± 1.48 mM to 20.76 ± 1.56 mM) during ischemia had 24.26% increase in infarct volume (P<0.05) and more serious neurological function deficits (P<0.05). The severe hyperglycemic rats also showed dramatically decreased proliferation of neural stem/progenitor cells (NSPCs) (P<0.05) and down-regulation of the phosphorylation of cyclic-AMP response element-binding protein (pCREB) (P<0.05)and brain-derived neurotrophic factor (BDNF) (P<0.05) in ipsilateral SVZ. But the above-mentioned detrimental effects were not observed in rats that were rendered with mild hyperglycemia (9.43 ± 1.39-10.13 ± 1.24 mM). Our findings indicate that severe instead of mild hyperglycemia exacerbates ischemic injury and inhibits stroke-induced SVZ neurogenesis by a mechanism involving suppression of CREB and BDNF signaling.

Functional characterization of the UDP-xylose biosynthesis pathway in Rhodothermus marinus.

UDP-glucuronic acid dehydrogenase (UGD) and UDP-xylose synthase (UXS) are the two enzymes responsible for the biosynthesis of UDP-xylose from UDP-glucose. Several UGDs from bacterial sources, which oxidize UDP-glucose to glucuronic acid, have been found and functionally characterized whereas only few reports on bacterial UXS isoforms exist. Rhodothermus marinus, a halothermophilic bacterium commonly found in hot springs, proved to be a valuable source of carbohydrate active enzymes of biotechnological interest, such as xylanases, mannanases, and epimerases. However, no enzymes of R. marinus involved in the biosynthesis or modification of nucleotide sugars have been reported yet. Herein, we describe the cloning and characterization of two putative UGD (RmUGD1 and RmUGD2) and one UXS (RmUXS) isoform from this organism. All three enzymes could be expressed in recombinant form and purified to near homogeneity. UPLC- and NMR-based activity tests showed that RmUGD1 and RmUXS are indeed active enzymes, whereas no enzymatic activity could be detected by RmUGD2. Both RmUGD1 and RmUXS showed a temperature optimum of 60 °C, with almost no loss of activity after 1 h exposure at 70 °C. No metal ions were required for enzymatic activities. Zn(2+) ions strongly inhibited both enzymes. RmUGD1 showed higher salt tolerance and had a higher pH optimum than RmUXS. Furthermore, RmUGD1 was inhibited by UDP-xylose at higher concentrations. By coupling recombinant RmUXS and RmUGD1, UDP-xylose could be successfully synthesized directly from UDP-glucose. The high activity of the herein described enzymes make RmUGD1 and RmUXS the first thermo-tolerant biocatalysts for the synthesis of UDP-glucuronic acid and UDP-xylose.

Discovery and characterization of a novel extremely acidic bacterial N-glycanase with combined advantages of PNGase F and A.

Peptide-N4-(N-acetyl-ß-glucosaminyl) asparagine amidases [PNGases (peptide N-glycosidases), N-glycanases, EC 3.5.1.52] are essential tools in the release of N-glycans from glycoproteins. We hereby report the discovery and characterization of a novel bacterial N-glycanase from Terriglobus roseus with an extremely low pH optimum of 2.6, and annotated it therefore as PNGase H+. The gene of PNGase H+ was cloned and the recombinant protein was successfully expressed in Escherichia coli. The recombinant PNGase H+ could liberate high mannose-, hybrid- and complex-type N-glycans including core α1,3-fucosylated oligosaccharides from both glycoproteins and glycopeptides. In addition, PNGase H+ exhibited better release efficiency over N-glycans without core α1,3-fucose compared with PNGase A. The facile expression, non-glycosylated nature, unusual pH optimum and broad substrate specificity of this novel type of N-glycanase makes recombinant PNGase H+ a versatile tool in N-glycan analysis.

Size dependence of the upconverted luminescence of NaYF4:Er,Yb microspheres for use in ratiometric thermometry.

The size-dependent temperature sensitivity is observed on the upconversion luminescence of NaYF4:Er,Yb microspheres with sizes between 0.7 and 2 µm that are prepared by a poly(acrylic acid)-assisted hydrothermal process. It is found that the fluorescence intensity ratio (FIR) of their green upconversion emissions (with peaks at 521 and 539 nm) is strongly size-dependent at temperatures between 223 and 403 K. As the size of the spheres increases from 0.7 to 1.6 µm, the maximum sensitivity decreases from 36.8 × 10(-4) to 24.7 × 10(-4) K(-1). This effect is mainly attributed to the larger specific surface area of the smaller spheres where a relatively large number of Er(III) ions are located at the surface. This results in an increase in the efficiency of the (4)S3/2 → (2)H11/2 population process of the Er(III) ions due to stronger electron-phonon interactions with increasing T. Heating of the spheres by NIR light is also supposed to cause enhanced electron-phonon interactions in such particles.