Three-Dimensional Bimetallic Ammonium K-Eu Nitrate with a Rare (6,6)-Connected Ion Topology Exhibiting Structural Phase Transition and Photoluminescence Properties

A K-Eu bimetallic ammonium metal-nitrate three-dimensional (3D) framework incorporating R-N-methyl-3-hydroxyquinuclidine, (RM3HQ)2KEu(NO3)6 (RM3HQ = R-N-methyl-3-hydroxyquinuclidine, 1), was characterized and reported. Distinguishing from the former hybrid rare-earth double perovskites, 1 adopts a mixed corner- and face-sharing K+/Eu3+-centered polyhedral connectivity to form a 3D inorganic framework, showing a rare (6, 6)-connected ion topology with a 66 framework. Notably, 1 exhibits clear phase transition, and the switchable thermodynamic behavior is confirmed by variable-temperature dielectric measurements and second-harmonic generation response. Moreover, 1 also shows photoluminescence properties. The activator Eu3+ plays a crucial role in this process, leading to a significant narrow emission at 592 nm with a photoluminescence quantum yield (PLQY) of 20.76%. The fluorescence lifetime (FLT) of 1 is 4.32 ms. This finding enriches the bimetallic hybrid system for potential electronic and/or luminescence applications.

Gas-Liquid Interface Route to Hybrid Copper Bromine Perovskite Single-Crystal Membrane with Dielectric Transitions and Ferromagnetic Exchanges

Single-crystal membranes (SCMs) show great promise in the fields of sensors, light-emitting diodes, and photodetection. However, the growth of a large-area single-crystal membranes is challenging. We report a new organic-inorganic SCMs [HCMA]2CuBr4 (HCMA = cyclohexanemethylamine) crystallized at the gas-liquid interface. It also has low-temperature ferromagnetic order, high-temperature dielectric anomalies, and narrow band gap indirect semiconductor properties. Specifically, the reversible phase transition of the compound occurs at 350/341 K on cooling/heating and exhibits dielectric anomalies and stable switching performance near the phase transition temperature. The ferromagnetic exchange interaction in the inorganic octahedra and the organic layer enables ferromagnetic ordering at low-temperature 10 K. Finally, the single crystal exhibits an indirect semiconducting property with a narrow band gap of 0.99 eV. Such rich multichannel physical properties make it a potential application in photodetection, information storage and sensors.

Zero-dimensional organic-inorganic hybrid manganese bromide with coexistence of dielectric-thermal double switches and efficient photoluminescence

Zero-dimensional (0D) hybrid metal halides have attracted much attention due to their rich composition, excellent optical stability, large exciton binding energy, etc. Photoelectric switchable multifunctional materials can integrate multiple physical properties (e.g., ferroelectricity, photoluminescence, magnetic, etc.) into one device and are widely used in many fields such as smart switches, sensors, etc. However, multifunctional materials with thermal energy storage, stimulant dielectric response, and light-emitting properties are rarely reported. Here, we synthesized a new organic-inorganic hybrid metal halide single crystal [TEMA]2MnBr4 (1) (TEMA+ = triethylmethylammonium). Compound 1 undergoes a reversible phase transition at a high temperature of 344/316 K, having a large thermal hysteresis of 28 K and exhibits high stability dielectric switching characteristics near the phase transition temperature. The single crystal exhibits green emission at 513 nm under UV excitation, originating from the 4T1g(G) → 6A1g(S) transition of Mn2+ ions. Excitingly, this single crystal's photoluminescence quantum yield (PLQY) is as high as 80.78%. This work provides a strategy for the development of organic-inorganic hybrid optoelectronic multifunctional materials with high-efficient light emission and switchable dielectric properties.

ADAMTS7-Mediated Complement Factor H Degradation Potentiates Complement Activation to Contributing to Renal Injuries

BACKGROUND

The dysfunction of complement factor H (CFH), the main soluble complement negative regulator, potentiates various complement-induced renal injuries. However, insights into the underlying mechanism of CFH dysfunction remain limited. In this study, we investigated whether extracellular protease-mediated degradation accounts for CFH dysfunction in complement-mediated renal injuries.

METHODS

An unbiased interactome of lupus mice kidneys identified CFH-binding protease. In vitro cleavage assay clarified CFH degradation. Pristane-induced SLE or renal ischemia-reperfusion (I/R) injury models were used in wild-type and ADAMTS7-/- mice.

RESULTS

We identified the metalloprotease ADAMTS7 as a CFH-binding protein in lupus kidneys. Moreover, the upregulation of ADAMTS7 correlated with CFH reduction in both lupus mice and patients. Mechanistically, ADAMTS7 is directly bound to CFH complement control protein (CCP) 1-4 domain and degraded CCP 1-7 domain through multiple cleavages. In mice with lupus nephritis or renal I/R injury, ADAMTS7 deficiency alleviated complement activation and related renal pathologies, but without affecting complement-mediated bactericidal activity. Adeno-associated virus-mediated CFH silencing compromised these protective effects of ADAMTS7 knockout against complement-mediated renal injuries in vivo.

CONCLUSION

ADAMTS7-mediated CFH degradation potentiates complement activation and related renal injuries. ADAMTS7 would be a promising anticomplement therapeutic target that does not increase bacterial infection risk.

[Recommendations for the diagnosis and treatment of connective tissue disease-associated interstitial lung disease in China]

Interstitial lung disease (ILD) is a frequent complication of patients with connective tissue disease (CTD) and significantly affects morbidity and mortality. Disease course may vary from stable or mildly progressive to more severe, with rapid loss of lung function. At present, there are great challenges and poor prognosis in the diagnosis and treatment of CTD-ILD. Based on the evidence and guidelines from China and other countries, experts from the Chinese Rheumatology Association developed standardization of diagnosis and treatment of CTD-ILD. The aim is to strengthen the early identification of, standardize the diagnosis and treatment of CTD-ILD, and delay the progress of the disease.

The type VI secretion system in Acinetobacter baumannii clinical isolates and its roles in antimicrobial resistance acquisition

Acinetobacter baumannii is a successful pathogen that can acquire various antibiotic resistance in a short time. However, little is known about how it can evolve from an antibiotic sensitive to a resistant phenotype. In this study, we investigated the roles of the type VI secretion system (T6SS) in the acquisition of antibiotic resistance of A. baumannii. T6SS gene cluster was found to be present in 51 of 77 A. baumannii clinical isolates, of which, it was found in 62% (8/13) of the multiple drug resistant (MDR) isolates, 90% (36/40) of the extensively drug-resistant (XDR) isolates and 26% (6/23) of the antibiotic sensitive isolates. There is a close relationship between the antimicrobial resistance and the presence of T6SS. Besides, T6SS + isolates showed lower biofilm formation activity and higher survival ability in the presence of normal human serum than T6SS- isolates. A. baumannii A152 with complete T6SS can outcompete E.coli effectively and can acquire the antibiotic resistance plasmids released by E.coli. In contrast, the T6SS core gene mutant A152Δhcp showed significantly decreased ability to acquire antimicrobial resistance plasmids from the prey bacteria. These results suggest that T6SS mediated bacterial competition plays important roles in the antimicrobial resistance of A. baumannii, which points out a new direction for us to study the antimicrobial resistance of A. baumannii.

Complete genome sequence and virulence characterization of a neonatal meningitis Escherichia coli isolate

Neonatal bacterial meningitis is a life-threatening disease in newborns, and neonatal meningitis Escherichia coli (NMEC) is the second most frequent bacteria causing this disease worldwide. In order to further understand the characteristics of this pathogen, an E. coli isolate W224 N from newborns with meningitis was sequenced for detailed genetic characterization and the virulence was tested by a series of phenotypic experiments. W224 N has a circular chromosome and three plasmids. It belongs to ST95 and the serotype is O18:H7. Comparative genomic analysis showed that W224 N was closely related to E. coli neonatal meningitis isolates RS218 and NMEC O18. There are 11 genomic islands in W224 N and most of the GIs are specific to W224 N. W224 N has most of the virulence factors other neonatal meningitis isolates have. The virulence genes located both on the genome and plasmid. At the same time, we found a virulence factor cdiA only present in W224 N but absent in the other five genomes analyzed. In vitro experiment showed that W224 N has strong serum resistance ability, low biofilm formation ability and high flagellar motility. It also has a very strong toxicity to mice and amoeba. The whole genome as well as in vitro and in vivo experiments showed that W224 N is a high virulent strain. The results can help us better learn about the pathogenicity of neonatal meningitis E. coli.

Proteomic Analyses of Acinetobacter baumannii Clinical Isolates to Identify Drug Resistant Mechanism

Acinetobacter baumannii is one of the main causes of nosocomial infections. Increasing numbers of multidrug-resistant Acinetobacter baumannii cases have been reported in recent years, but its antibiotic resistance mechanism remains unclear. We studied 9 multidrug-resistant (MDR) and 10 drug-susceptible Acinetobacter baumannii clinical isolates using Label free, TMT labeling approach and glycoproteomics analysis to identify proteins related to drug resistance. Our results showed that 164 proteins exhibited different expressions between MDR and drug-susceptible isolates. These differential proteins can be classified into six groups: a. proteins related to antibiotic resistance, b. membrane proteins, membrane transporters and proteins related to membrane formation, c. Stress response-related proteins, d. proteins related to gene expression and protein translation, e. metabolism-related proteins, f. proteins with unknown function or other functions containing biofilm formation and virulence. In addition, we verified seven proteins at the transcription level in eight clinical isolates by using quantitative RT-PCR. Results showed that four of the selected proteins have positive correlations with the protein level. This study provided an insight into the mechanism of antibiotic resistance of multidrug-resistant Acinetobacter baumannii.

Roles of the Hcp family proteins in the pathogenicity of Salmonella typhimurium 14028s

The type VI secretion system (T6SS) is a new secretion system that is widely distributed among Gram-negative bacteria. The core component hemolysin-coregulated protein (Hcp) can be used as both its structural protein and secretory protein or chaperone protein. Studies on Hcp are important to elucidate the overall virulence mechanism of T6SS. Salmonella typhimurium is an important foodborne pathogen. There are three copies of hcp genes identified in S. Typhimurium 14028s. This study aimed to characterize the functions of the three Hcp family proteins and to elucidate the interactions among them. The hcp gene deletion mutants were constructed by λ Red-based recombination system. Effects of hcp mutation on the pathogenicity of 14028s were studied by bacterial competition assays, Dictyostelium discoideum assays and mouse model. The three Hcp family proteins were found to play different roles. Hcp1 can affect the transcription of rpoS and type 2 flagellar gene and influence the motility of 14028s. It is also involved in the intracellular survival of 14028s in Dictyostelium discoideum; Hcp2 is involved in the early proliferative capacity of 14028s in mice and can prevent its excessive proliferation; Hcp3 did not show direct functions in these assays. Hcp1 can interact with Hcp2 and Hcp3. Deletion of one hcp gene can result in a transcription level variation in the other two hcp genes. Our findings elucidated the functions of the three Hcp family proteins in S.Typhimurium and illustrated that there are interactions between different Hcp proteins. This study will be helpful to fully understand how T6SS actions in an organism.

Effects of anti-Helicobacter pylori concomitant therapy and probiotic supplementation on the throat and gut microbiota in humans

The microbiota within humans maintains homeostasis and plays important roles in human health. However, some situations such as the use of antibiotics may disrupt the microbiota balance and result in a series of adverse effects. This study aimed to investigate the effects of a commonly used anti-Helicobacter pylori concomitant therapy on the composition of the gut and throat microbiota and any antibiotic resistance that may develop. In addition to the standard regimen, two different supplementary probiotic regimens that both used Saccharomyces boulardii were included. Microbiological culture-based techniques were used to analyse the microbiota composition and antibiotic resistance. Our results showed marked quantitative and qualitative alterations in both the gut and throat microbiota after treatment with not only the standard concomitant therapy but also with either supplementary probiotic regimen. Nevertheless, most of the changes in the gut microbiota (except for yeast and Bacteroides spp. counts) reverted by Day 71, whereas the alterations in the throat microbiota appeared to persist. Patients treated with the eradication therapy in the absence of probiotic supplementation experienced the most pronounced disturbances in the throat microbiota, whereas changes in the throat microbiota appeared to stabilize in the groups that received probiotic supplementation. We also detected higher antibiotic resistance rates for Enterobacteriaceae, Enterococcus spp. and Bacteroides spp. after treatment with the eradication therapy. Co-administration of probiotics is likely to be more effective than post-antibiotic supplementation, and although some beneficial effects were observed, the probiotic combination did not exert significant effects on the unbalanced commensal gut and throat microbiota composition.

High remission and low relapse with prolonged intensive DMARD therapy in rheumatoid arthritis (PRINT): A multicenter randomized clinical trial

OBJECTIVES

To determine whether prolonged intensive disease-modifying antirheumatic drug (DMARD) treatment (PRINT) leads to high remission and low relapse rates in patients with severe rheumatoid arthritis (RA).

METHODS

In this multicenter, randomized and parallel treatment trial, 346 patients with active RA (disease activity score (28 joints) [DAS28] (erythrocyte sedimentation rate [ESR]) > 5.1) were enrolled from 9 centers. In phase 1, patients received intensive treatment with methotrexate, leflunomide, and hydroxychloroquine, up to 36 weeks, until remission (DAS28 ≤ 2.6) or a low disease activity (2.6 < DAS28 ≤ 3.2) was achieved. In phase 2, patients achieving remission or low disease activity were followed up with randomization to 1 of 2 step-down protocols: leflunomide plus hydroxychloroquine combination or leflunomide monotherapy. The primary endpoints were good European League Against Rheumatism (EULAR) response (DAS28 (ESR) < 3.2 and a decrease of DAS28 by at least 1.2) during the intensive treatment and the disease state retention rate during step-down maintenance treatment. Predictors of a good EULAR response in the intensive treatment period and disease flare in the maintenance period were sought.

RESULTS

A good EULAR response was achieved in 18.7%, 36.9%, and 54.1% of patients at 12, 24, and 36 weeks, respectively. By 36 weeks, 75.4% of patients achieved good and moderate EULAR responses. Compared with those achieving low disease activity and a high health assessment questionnaire (HAQ > 0.5), patients achieving remission (DAS28 ≤ 2.6) and low HAQ (≤ 0.5) had a significantly higher retention rate when tapering the DMARDs treatment (P = 0.046 and P = 0.01, respectively). There was no advantage on tapering to combination rather than monotherapy.

CONCLUSIONS

Remission was achieved in a proportion of patients with RA receiving prolonged intensive DMARD therapy. Low disease activity at the start of disease taper leads to less subsequent flares. Leflunomide is a good maintenance treatment as single treatment.

Genotyping of Salmonella with lineage-specific genes: correlation with serotyping

BACKGROUND

The bacterial genus Salmonella encompasses a large number of serotypes that are genetically very similar but biologically quite different, especially in pathogenic properties and host specificity. Serotyping has been used for the classification, identification, and epidemiological investigation due to its excellent discriminating power, but it cannot distinguish the different pathogenic lineages within a polyphyletic serotype. Additionally, very few institutions have the comprehensive set of antisera for typing. Therefore various studies have been performed to explore alternative assays to differentiate Salmonella isolates, such as the search for genes that can be used as potential molecular substitutes for serotyping. However, the genes tested so far have often given inconsistent results.

METHODS

In this study, the discriminating power of seven genes to differentiate 309 Salmonella strains representing 26 serotypes was evaluated and the results were compared with those of other methods.

RESULTS

The seven newly selected genes have a good power to differentiate different serovars. The tree based on the concatenated sequences of these genes revealed phylogenetic relationships of the bacteria consistent with that of the whole genome tree.

CONCLUSION

Individual Salmonella lineages each have specific genes that can be used to differentiate Salmonella isolates on a phylogenetic basis.

Magnetic resonance imaging in early rheumatoid arthritis: a multicenter, prospective study

To identify the magnetic resonance imaging (MRI) features of hands and wrists in early rheumatoid arthritis (RA). A total of 129 early arthritis patients (≤1 year) were enrolled in the study. At presentation, MRI of the hands was performed, with clinical and laboratory analyses. After a 1-year follow-up, clinical diagnosis of early RA or non-RA was confirmed by two rheumatologists. The characteristics of MRI variables at baseline in RA patients not fulfilling ACR 1987 criteria [RA-87(-)] were compared with those fulfilling ACR1987 criteria [RA-87(+)] and non-RA. In the 129 early arthritis patients, 90 were diagnosed with RA in a 1-year follow-up. There were 47.8 % (43/90) of the RA patients not fulfilling ACR 1987 criteria [RA-87(-)]. The scores of synovitis in RA-87(-) patients were similar with those in RA-87(+) [Synovitis score, 14.0 (IQR, 4.0-25.0) vs. 14.0 (IQR, 10.0-25.0), p > 0.05]. Compared with those in non-RA, RA-87(-) patients had higher synovitis scores and occurrence of synovitis in proximal interphalangeal (PIP) joints [synovitis score, 14.0 (IQR, 4.0-25.0) vs. 6.0 (IQR, 2.0-14.5), p = 0.046; occurrence of PIP synovitis: 53.5 vs. 27.3 %, p = 0.02]. There was no significant difference of bone marrow edema, bone erosion, and tenosynovitis between RA-87(-) and non-RA. Synovitis in PIP joints was independent predictor for RA-87(-) [OR, 3.1 (95 %CI 1.2-8.1)]. High synovitis scores and synovitis in PIP joints on MRI were important in early RA, especially those not fulfilling ACR 1987 criteria.

Comparative genomic analysis between typhoidal and non-typhoidal Salmonella serovars reveals typhoid-specific protein families

BACKGROUND

The genus Salmonella contains more than 2600 serovars. While most cause a self-limiting gastroenteritis, four serovars, S. Typhi, S. Paratyphi A, B and C, elicit typhoid, a potentially fatal systemic infection. Because of the prevalence in certain regions, such as South Asia, and the disease severity of typhoidal Salmonella infections, comprehensive studies are needed to elucidate the pathogenesis of diseases caused by these typhoidal serovars.

RESULTS

We performed comparative genomic analyses on eight human typhoidal strains and 27 non-human typhoidal Salmonella strains to elucidate their evolutionary relationships and identify the genes specific to the four typhoidal serovars. Our results indicate that Salmonella may have an open pan-genome. A core-genome based phylogeny demonstrated that divergence between S. Paratyphi A and S. Typhi took place not long ago and S. Paratyphi B shared a recent common ancestor with S. Paratyphi C. Of great interest, the divergence between S. Paratyphi B and S. Paratyphi C was shown to be more recent than that between S. Paratyphi A and S. Typhi. Alignment and comparisons of the genomes identified unique complements of protein families to each of the typhoidal serovars. Most of these protein families are phage related and some are candidate virulence factors. Importantly, we found 88 protein families specific to two to three of the four typhoidal serovars. All but two of the 88 genes are present in S. Typhi, with a few in the three paratyphoidal serovars but none in the non-human typhoidal serovars. Most of these genes are predicted to encode hypothetical proteins and some are known to code for virulence factors such as Vi polysaccharide related proteins.

CONCLUSIONS

By comprehensive genomic comparisons, we identified protein families specific to the human typhoidal serovars, which will greatly facilitate investigations on typhoid pathogenesis.

Identification of genes to differentiate closely related Salmonella lineages

Background

Salmonella are important human and animal pathogens. Though highly related, the Salmonella lineages may be strictly adapted to different hosts or cause different diseases, from mild local illness like gastroenteritis to fatal systemic infections like typhoid. Therefore, rapid and accurate identification of Salmonella is essential for timely and correct diagnosis of Salmonella infections. The current identification methods such as 16S rRNA sequencing and multilocus sequence typing are expensive and time consuming. Additionally, these methods often do not have sufficient distinguishing resolution among the Salmonella lineages.

Methodologies/Principal Findings

We compared 27 completely sequenced Salmonella genomes to identify possible genomic features that could be used for differentiation of individual lineages. We concatenated 2372 core genes in each of the 27 genomes and constructed a neighbor-joining tree. On the tree, strains of each serotype were clustered tightly together and different serotypes were unambiguously separated with clear genetic distances, demonstrating systematic genomic divergence among the Salmonella lineages. We made detailed comparisons among the 27 genomes and identified distinct sets of genomic differences, including nucleotide variations and genomic islands (GIs), among the Salmonella lineages. Two core genes STM4261 and entF together could unambiguously distinguish all Salmonella lineages compared in this study. Additionally, strains of a lineage have a common set of GIs and closely related lineages have similar sets of GIs.

Conclusions

Salmonella lineages have accumulated distinct sets of mutations and laterally acquired DNA (e.g., GIs) in evolution. Two genes entF and STM4261 have diverged sufficiently among the Salmonella lineages to be used for their differentiation. Further investigation of the distinct sets of mutations and GIs will lead to novel insights into genomic evolution of Salmonella and greatly facilitate the elucidation of pathogeneses of Salmonella infections.

Helicobacter pylori in the oral cavity and gastric mucosa: a meta-analysis

BACKGROUND

Helicobacter pylori have been found in the oral cavity and stomach. This study is to establish whether there might be any associations between isolates of H. pylori in the oral cavity and those in the stomach by meta-analysis.

METHODS

Studies reporting raw data on the prevalence of H. pylori infection in the oral cavity in gastric H. pylori-positive and H. pylori-negative patients, in patients with gastroesophageal diseases, and in healthy individuals and studies reporting data on the eradication rate in the oral cavity or stomach, published in the English language, were identified through MEDLINE and EMBASE up to May 2010.

RESULTS

The prevalence of H. pylori infection in the oral cavity in gastric H. pylori-positive patients was significantly higher (45.0%) than that in gastric H. pylori-negative patients (23.9%). The pooled odds ration (OR) was 3.61 and the 95% CI was 1.91-6.82 (P < 0.0001). Different diagnostic methods produced different pooled ORs with PCR the highest (OR = 5.11, 95% CI: 2.08-12.54, P = 0.0004) and rapid urease test (RUT) the lowest (OR = 2.00, 95% CI: 0.80-5.00, P = 0.14). The 44.8% (91/203) prevalence of H. pylori infection in the oral cavity in patients with clinical and/or histological gastroesophageal diseases was significantly higher than the 13.2% (21/159) in patients with non-ulcerous dyspepsia or healthy controls (OR = 5.15, 95% CI: 2.97-8.92, P < 0.00001). The eradication efficiency in stomach is 85.8% (187/218), while in oral cavity it is only 5.7% (9/158). The OR is 55.59, P < 0.00001.

CONCLUSIONS

There is a close relation between the infection of H. pylori in the oral cavity and stomach. H. pylori in the oral cavity are more difficult to be eradicated than in the stomach. It may be a source of reinfection.

SPC-P1: a pathogenicity-associated prophage of Salmonella paratyphi C

Background

Salmonella paratyphi C is one of the few human-adapted pathogens along with S. typhi, S. paratyphi A and S. paratyphi B that cause typhoid, but it is not clear whether these bacteria cause the disease by the same or different pathogenic mechanisms. Notably, these typhoid agents have distinct sets of large genomic insertions, which may encode different pathogenicity factors. Previously we identified a novel prophage, SPC-P1, in S. paratyphi C RKS4594 and wondered whether it might be involved in pathogenicity of the bacteria.

Results

We analyzed the sequence of SPC-P1 and found that it is an inducible phage with an overall G+C content of 47.24%, similar to that of most Salmonella phages such as P22 and ST64T but significantly lower than the 52.16% average of the RKS4594 chromosome. Electron microscopy showed short-tailed phage particles very similar to the lambdoid phage CUS-3. To evaluate its roles in pathogenicity, we lysogenized S. paratyphi C strain CN13/87, which did not have this prophage, and infected mice with the lysogenized CN13/87. Compared to the phage-free wild type CN13/87, the lysogenized CN13/87 exhibited significantly increased virulence and caused multi-organ damages in mice at considerably lower infection doses.

Conclusions

SPC-P1 contributes pathogenicity to S. paratyphi C in animal infection models, so it is possible that this prophage is involved in typhoid pathogenesis in humans. Genetic and functional analyses of SPC-P1 may facilitate the study of pathogenic evolution of the extant typhoid agents, providing particular help in elucidating the pathogenic determinants of the typhoid agents.

Localization of cerebral functional deficits in patients with non-neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NP-SLE) is a common complication of systemic lupus erythematosus (SLE), and clinical interventions are of only limited efficacy despite relatively high prevalence. Such complications have been studied extensively, but the pathoetiology of NP-SLE has not yet been elucidated. Diagnosis of NP-SLE focuses primarily on psychological manifestations, and the underlying mechanisms leading to neuropsychiatric complications remain unknown. To address potential changes in brain function before NP-SLE development, we used resting-state functional magnetic resonance imaging (MRI) to compare regional brain activity in SLE patients versus matched controls. We report that regional activity in cerebellum and in areas of the default mode network are attenuated in patients with SLE, and moreover individual alterations in cerebellar activity correlated positively with the disease activity index. These findings provide direct evidence that significant alteration of brain function, resembling that observed in patients with NP-SLE, is already present in SLE patients without neuropsychiatric complications, highlighting the need for early evaluation and intervention in SLE patients. Furthermore, the disease activity rating correlated with regional functional alterations in the cerebellum, suggesting that the cerebellum could play a role in the pathogenesis of NP-SLE.

Proteome analysis of Neisseria meningitidis serogroup strains C associated with outbreaks in China

OBJECTIVE

During 2003-2005, an outbreak of meningitis due to Neisseria meningitidis serogroup C occurred in China. With the aim to find strain clues result in the final epidemics, the ancestral strain 053442, a clinical isolate, and a carrier strain 053426 with different gene type were analyzed.

METHODS

Clinical strain 053442 and carrier strain 053426 were cultured on GC agar plates under the same condition. Two-dimensional electrophoresis was performed using the pH 3-10 nonlinear IPG strips of 24 cm length, and all the protein spots were identified by matrix-assisted laser desorption/ionization time of flight spectrometry.

RESULTS

502 and 380 protein spots were identified in 053426 and 053442 respectively, relating to 266 and 202 different genes covering a wide range of cellular functions. The express volume and number of proteins involved in energy metabolism, protein synthesis and amino acid biosynthesis in 053426 were higher than in 053442. Virulence factor Opa, Opc and a series of proteins involved in pilus assembly and retraction were identified in 053442, which appear to be of primary importance in colonization and invasion of human cells. Compared to 053442, virulence protein species were less in 053426, with lower express volumes too. No Opa and Opc were detected in 053426.

CONCLUSIONS

The different protein expression profiles of the clinical strain 053442 and carrier strain 053426 in the present study provide some clues of the different pathogenicity of the two strains, which may account for result in the final epidemics.

Salmonella paratyphi C: genetic divergence from Salmonella choleraesuis and pathogenic convergence with Salmonella typhi

Background

Although over 1400 Salmonella serovars cause usually self-limited gastroenteritis in humans, a few, e.g., Salmonella typhi and S. paratyphi C, cause typhoid, a potentially fatal systemic infection. It is not known whether the typhoid agents have evolved from a common ancestor (by divergent processes) or acquired similar pathogenic traits independently (by convergent processes). Comparison of different typhoid agents with non-typhoidal Salmonella lineages will provide excellent models for studies on how similar pathogens might have evolved.

Methodologies/Principal Findings

We sequenced a strain of S. paratyphi C, RKS4594, and compared it with previously sequenced Salmonella strains. RKS4594 contains a chromosome of 4,833,080 bp and a plasmid of 55,414 bp. We predicted 4,640 intact coding sequences (4,578 in the chromosome and 62 in the plasmid) and 152 pseudogenes (149 in the chromosome and 3 in the plasmid). RKS4594 shares as many as 4346 of the 4,640 genes with a strain of S. choleraesuis, which is primarily a swine pathogen, but only 4008 genes with another human-adapted typhoid agent, S. typhi. Comparison of 3691 genes shared by all six sequenced Salmonella strains placed S. paratyphi C and S. choleraesuis together at one end, and S. typhi at the opposite end, of the phylogenetic tree, demonstrating separate ancestries of the human-adapted typhoid agents. S. paratyphi C seemed to have suffered enormous selection pressures during its adaptation to man as suggested by the differential nucleotide substitutions and different sets of pseudogenes, between S. paratyphi C and S. choleraesuis.

Conclusions

S. paratyphi C does not share a common ancestor with other human-adapted typhoid agents, supporting the convergent evolution model of the typhoid agents. S. paratyphi C has diverged from a common ancestor with S. choleraesuis by accumulating genomic novelty during adaptation to man.

Proteome analysis of sorbitol fermentation specific protein inVibrio cholerae by 2-DE and MS

Vibrio cholerae can be differentiated into epidemic and non-epidemic strains by sorbitol fermentation speed, but little research has been done on its mechanisms. In this study, we investigated differential protein expression of the two strains in response to sorbitol metabolism. V. cholerae strains were cultured in media with and without sorbitol, respectively. Proteins were separated by 2-DE, and those that showed different expression in the two media were identified by MALDI-TOF MS. Fifteen proteins in epidemic strains and 11 proteins in non-epidemic strains showed a different expression in sorbitol medium. Among them, 4 proteins were common to epidemic and non-epidemic strains. Gene sequence analysis showed that some mutations occurred in these proteins between the two strains. Potential functions of these proteins included sugar uptake, amino acid uptake, electron transport, sulfate and thiosulfate transport.

Effects of transfection reagents and Helicobacter pylori on morphology of AGS cells

AIM: To investigate the effects of different transfection reagents on the morphology of AGS cells and to explore whether these reagents can induce humming bird type of AGS cells as Helicobacter pylori (H. pylori) does.

METHODS: AGS cells were transfected with polycation transfection reagents (polyethylenimine, Sofast Cell Transfection reagent) and the new generation of lipid transfection reagents (Effectene Transfection Reagent). Then morphological changes of the cells were observed. Meanwhile, AGS cells were infected with H. pylori 26695, and then the morphology of the cells was compared with that of the cells transfected with transfection reagents.

RESULTS: H. pylori 26695 induced humming bird type of AGS cells 4 h after infection. Both polycation transfection reagents also induced humming bird type of AGS cells, and the cells were elongated in shape, which was similar to that induced by H. pylori 26695. The humming bird type always appeared whether the cells were transfected with DNA or without DNA at 4 h. The morphological changes were positively related with the dosages of the reagents. The apoptosis of the cells were observed when 10 µL reagents were used, and it became severe as the dosage reached 15 µL. The new generation of lipid transfection reagents had no effect on the morphology of AGS cells.

CONCLUSION: Polycation transfection reagents should not be used in the research of AGS cell morphology. Further study should be performed to find out whether there are some common pathways between the morphology variation induced by H　pylori and polycation transfection reagents.

[An epidemiological study on etiology of mental retardation]

A cross-sectional epidemiological study was conducted to assess the prevalence and etiology of mental retardation (MR) among children under 14 years of age. The definition of MR and the criteria for diagnosis were adopted from WHO (1985). The IQ/DQ was evaluated with standardized psychological tests. The etiology of MR was specified by medical, genetic and psychosocial studies. A total of 862 retarded children were found among 85,170 surveyed. The overall adjusted prevalence rate was 1.20%. The percentage of mild, moderate, severe and profound MR was 60.6%, 22.7%, 9.6%, and 7.1%, respectively. Specific causes were found in 673 cases (79.1%). The etiology was unknown in 21.9% children. Timing of the causes showed prenatal in 34% perinatal 11.9%, postnatal 33%. Biomedical causes consisted of 89.6% and sociocultural factors, 10.4%. Among the prenatal factors, genetic diseases ranked first and manifested as chromosomal abnormalities and inborn errors of metabolism. Among the postnatal causes, sequelae of CNS infections and other forms of acquired brain insult were most important. Most children of socio-cultural MR were at school age and of the mild category. Our results show that most MR cases are preventable.