[The identification of a novel reassortant H3N2 avian influenza virus based on nanopore sequencing technology and genetic characterization].

Objective: To identify a novel reassortant H3N2 avian influenza virus using nanopore sequencing technology and analyze its genetic characteristics. Methods: The positive samples of the H3N2 avian influenza virus, collected from the external environment in the farmers' market of Guangzhou, were cultured in chicken embryos. The whole genome was sequenced by targeted amplification and nanopore sequencing technology. The genetic characteristics were analyzed using bioinformatics software. Results: The phylogenetic trees showed that each gene fragment of the strain belonged to the Eurasian evolutionary branch, and the host source was of avian origin. The HA gene was closely related to the origin of the H3N6 virus. The NA gene was closely related to the H3N2 avian influenza virus from 2017 to 2020. The PB1 gene was closely related to the H5N6 avian influenza virus in Guangxi Zhuang Autonomous Region and Fujian Province from 2016 to 2022 and was not related to the PB1 gene of the H5N6 avian influenza epidemic strain in Guangzhou. The other internal gene fragments had complex sources with significant genetic diversity. Molecular characteristics indicated that the strain exhibited the molecular characteristics of a typical low pathogenic avian influenza virus and tended to bind to the receptors of avian origin. On important protein sites related to biological characteristics, this strain had mutations of PB2-L89V, PB1-L473V, NP-A184K, M1-N30D/T215A, and NS1-P42S/N205S. Conclusions: This study identified a novel reassortant H3N2 avian influenza virus by nanopore sequencing, with the PB1 gene derived from the H5N6 avian influenza virus. The virus had a low ability to spread across species, but further exploration was needed to determine whether its pathogenicity to the host was affected.

[Metagenomic data-analysis reveals enrichment of lipopolysaccharide synthesis in the gut microbiota of atrial fibrillation patients].

Objective: To investigate the functional changes of key gut microbiota (GM) that produce lipopolysaccharide (LPS) in atrial fibrillation (AF) patients and to explore their potential role in the pathogenesis of AF. Methods: This was a prospective cross-sectional study. Patients with AF admitted to Beijing Chaoyang Hospital of Capital Medical University were enrolled from March 2016 to December 2018. Subjects with matched genetic backgrounds undergoing physical examination during the same period were selected as controls. Clinical baseline data and fecal samples were collected. Bacterial DNA was extracted and metagenomic sequencing was performed by using Illumina Novaseq. Based on metagenomic data, the relative abundances of KEGG Orthology (KO), enzymatic genes and species that harbored enzymatic genes were acquired. The key features were selected via the least absolute shrinkage and selection operator (LASSO) analysis. The role of GM-derived LPS biosynthetic feature in the development of AF was assessed by receiver operating characteristic (ROC) curve, partial least squares structural equation modeling (PLS-SEM) and logistic regression analysis. Results: Fifty nonvalvular AF patients (mean age: 66.0 (57.0, 71.3), 32 males(64%)) were enrolled as AF group. Fifty individuals (mean age 55.0 (50.5, 57.5), 41 males(82%)) were recruited as controls. Compared with the controls, AF patients showed a marked difference in the GM genes underlying LPS-biosynthesis, including 20 potential LPS-synthesis KO, 7 LPS-biosynthesis enzymatic genes and 89 species that were assigned as taxa harbored nine LPS-enzymatic genes. LASSO regression analysis showed that 5 KO, 3 enzymatic genes and 9 species could be selected to construct the KO, enzyme and species scoring system. Genes enriched in AF group included 2 KO (K02851 and K00972), 3 enzymatic genes (LpxH, LpxC and LpxK) and 7 species (Intestinibacter bartlettii、Ruminococcus sp. JC304、Coprococcus catus、uncultured Eubacterium sp.、Eubacterium sp. CAG:251、Anaerostipes hadrus、Dorea longicatena). ROC curve analysis revealed the predictive capacity of differential GM-derived LPS signatures to distinguish AF patients in terms of above KO, enzymatic and species scores: area under curve (AUC)=0.957, 95%CI: 0.918-0.995, AUC=0.940, 95%CI 0.889-0.991, AUC=0.972, 95%CI 0.948-0.997. PLS-SEM showed that changes in lipopolysaccharide-producing bacteria could be involved in the pathogenesis of AF. The key KO mediated 35.17% of the total effect of key bacteria on AF. After incorporating the clinical factors of AF, the KO score was positively associated with the significantly increased risk of AF (OR<0.001, 95%CI:<0.001-0.021, P<0.001). Conclusion: Microbes involved in LPS synthesis are enriched in the gut of AF patients, accompanied with up-regulated LPS synthesis function by encoding the LPS-enzymatic biosynthesis gene.

[Molecular-related epidemic characteristics of influenza A (H3N2) viruses in Guangzhou, 2019].

Objective: To isolate the influenza A (H3N2) viruses from different sources in Guangzhou in 2019 and analyze these viruses' evolution and variation characteristics. Methods: The hemagglutinin (HA) and neuraminidase (NA) genes of H3N2 isolates from outpatient monitoring, influenza outbreaks, and inpatient severe cases in Guangzhou in 2019 were sequenced. Bioinformatics software analyzed the variations and evolution characteristics of HA and NA genes. Results: The epidemic peaks of influenza A (H3N2) viruses were made up of period Ⅰ (from January to August) and period Ⅱ (from November to December). The positive rate of influenza A (H3N2) in males was 13.46% (703/5 221), which was higher than that in females (11.50%, 510/4 435) (χ2=8.43,P=0.00). The group's positive rate of 10-20 years old was the highest (25.18%,665/2 641). The isolates from different sources were highly homologous and closely related to 3C.2a.1 branches, which could be further divided into three small groups of Group 1-3. Gene recombination was observed between different branches. The mutations of HA antigen sites gradually appeared from Group 1 to Group 3, leading to new antigen drift. Variations of HA antigenic sites mainly occurred in the region of A and B. The mutations of receptor binding sites of Group 1 and Group 3 viruses occurred in the anterior and posterior walls. There were two glycosylation sites lacked on region A of HA antigen observed in the isolates of Group 2-3. Conclusions: Genetic variations of H3N2 influenza viruses in Guangzhou included gene mutations and gene recombination. Under the pressure of the vaccine, the evolution of viruses was rapid. Therefore, the monitoring of molecular-related epidemic characteristics of the H3N2 influenza virus was necessary.

Two classic OBPs modulate the responses of female Holotrichia oblita to three major ester host plant volatiles.

Insects possess a fairly sophisticated olfactory system in their antennae to detect odorants essential for their survival and reproduction. Among them, insect first perceives odour sources by odorant-binding proteins (OBPs) to locate host-plants. Methyl salicylate, (Z)-3-hexenyl acetate and dibutyl phthalate are major volatile components of Ulmus pumila and Ricinus communis and elicit strong responses of the scarab beetle Holotrichia oblita adults. However, olfactory perception of the scarab beetle to these odorant compounds is unclear. In the current study, we cloned the OBP6 and OBP7 of H. oblita. The expression pattern shows that the two genes were highly expressed in the antennae of female beetles. Binding assays verified that the HoblOBP6 had a better binding affinity to methyl salicylate, and so did HoblOBP7 to (Z)-3-hexenyl acetate and dibutyl phthalate. The effect on the responses of female beetles to the three compounds was decreased significantly after these two genes were silenced by RNA interference. These results indicate that HoblOBP6 and HoblOBP7 are essential for female H. oblita perception of methyl salicylate, (Z)-3-hexenyl acetate and dibutyl phthalate. Our study provides important insights into the olfactory mechanism of female H. oblita to ester plant volatiles and could facilitate the development of potential pest control strategies in the field.

[Efficacy comparison of primary percutaneous coronary intervention by drug-coated balloon angioplasty or drug-eluting stenting in acute myocardial infarction patients with de novo coronary lesions].

Objective: To compare the safety profile, angiographic and clinical outcomes between drug-coated balloon(DCB) only strategy versus drug eluting stent(DES) implantation in primary percutaneous coronary intervention(PCI) for acute myocardial infarction(AMI) patients. Methods: A total of 380 AMI patients who underwent primary PCI in Beijing Chaoyang Hospital from January 2016 to May 2019 were enrolled. They were allocated into DEB group(n=180) or DES group(n=200). The Primary endpoint was the major adverse cardiac events(MACE) in hospital and within 3 months after discharge, the composite event of cardiac death, non-fatal myocardial infarction(MI), target vessel revascularization(TVR) and in stent thrombosis. The secondary endpoints included: (1)TIMI blood flow grade and myocardial perfusion grade (TMP grade) of infarct-related vessels before and after PCI. (2)The degree of ST segment resolution(STR) between half hour and two hours after PCI, and STR was represented by percentage of summed ST-segment reduction between baseline and post-PCI. Using the most significant lead of ST segment elevation, calculating the rate of decline in the ST segment after treatment; or the most significant lead of the ST segment depression, to calculate the rate of recovery in the ST segment after treatment. STR<50% was defined as incomplete STR. (3)The occurrence of coronary artery dissection during operation. (4)The peak value of myocardial enzymes. (5)The incidence of bleeding in hospital and within 3 months after discharge. The inverse probability weighting method based on propensity score (IPTW) was used to compare the effects of the two treatments on MACE occurrence in the logistic regression model. Results: There was no significant difference in sex, age, risk factors of coronary heart disease, type and site of AMI, interventional therapy data(P>0.05) between the two groups. The ratio of bifurcation lesions in DCB group was significantly higher than that in DES group, and the diameter of the DCB was smaller while the length was longer than that of DES (all P<0.05). One death occurred in each group during hospitalization. Compared with the DES group, the incidence of MI ï¼»2.8%(5/180) vs. 0.5% (1/200), P=0.10ï¼½ and TVR ï¼»2.8%(5/180) vs. 0.5%(1/200), P=0.10ï¼½ in the DCB group during hospitalization showed an increasing trend, and were mostly associated with delayed coronary dissection. The incidence of MACE was similar between the two groups (3.3%(6/180) and 1.0%(2/200), P=0.15) during hospitalization. There was no MACE occurred in the two groups within 3 months after discharge. There was no significant difference between the two groups in TIMI grade, TMP grade, incomplete STR rate and peak value of myocardial enzyme (all P>0.05). The incidence of coronary artery dissection was significantly higher in DCB group than in DES group (8.3%(15/180) and 3.0%(6/200), P=0.02), but most of them were type B or A dissection and did not need special treatment. There was no significant difference in bleeding event between the two groups(P=0.91). Logistic regression analysis showed that there was no difference in the risk of MACE during hospitalization between DES and DCB groups for AMI patients receiving PCI (compared with DCB, OR=0.35, 95%CI 0.08-1.43, P=0.13). Conclusions: The initial safety and efficacy profiles of DCB are similar with those of DES for the AMI patients during PCI. The study highlights that the incidence of coronary dissection (type A or B) is higher post DCB treatment than post DES, but it does not affect blood flow. However, the incidence of in-hospital MI due to delayed coronary dissection trends to be higher post DCB. So we should pay close attention to the risk of delayed coronary dissection after DCB in AMI patients with de novo lesion.

[Epidemiological and genetic characteristics of H5 subtype avian influenza virus in Guangzhou, 2014-2019].

Objective: To analyze the characteristics of spread and genetic evolution of H5 subtype avian influenza virus in Guangzhou from 2014 to 2019. Methods: H5 subtype virus was detected by fluorescence quantitative RT-PCR from the environmental samples in Guangzhou poultry markets. The genes of HA and NA of 48 isolates randomly selected were sequenced, including 46 isolates from environmental samples and 2 isolates from cases. The characteristics of molecular variation and genetic evolution were analyzed by using bioinformatics software. Results: A total of 1 094 strains of H5 subtype avian influenza virus were isolated from 52 284 samples (2.09%). All the strains belonged to Clade 2.3.4.4.C. NA gene belonged to H6N6 of Eurasian lineage. The cleavage sites of all the strains showed the characteristics of highly pathogenicity. Receptor binding sites were avian-derived receptors. However, mutations of S123P, S133A and T156A occurred, which implied that these strains could tend to bind to human receptors. There was an additional glycosylation site at 140 in strains isolated after 2017. The variation of antigen loci mainly occurred in B and E regions. Conclusions: H5 subtype avian influenza virus spread in Guangzhou from 2014 to 2019 with annual increased proportion of positive rate, and the sequencing results indicated that it belonged to Clade 2.3.4.4.C of H5N6 highly pathogenic virus, and genetic evolution and mutation continued, especially the common mutations which could enhance the binding capacity to human receptors. It is necessary to strengthen the surveillance.

[Epidemiological characteristics of a case infected with avian influenza A (H5N6) virus associated with exposure to aerosol].

Objective: To investigate the epidemiological and clinical characteristics of a case infected with avian influenza A (H5N6) virus associated with exposure to aerosol and provide evidence for the prevention and control of human infection with avian influenza virus. Methods: Epidemiological investigation was conducted to identify the history of exposure, infection route, and disease progression. Real-time fluorescent quantitative RT-PCR was used to test the samples collected from the case, close contacts, environment and poultry market. Results: The case had no history of exposure to live poultry and poultry market. But before the onset the case had a history of exposure to the live poultry placed in a car with doors and windows closed. The samples collected from the case's lower respiratory tract and the remaining frozen chicken meat were all influenza A (H5N6) virus positive. Conclusions: The source of infection was the live poultry, and the infection route might be the exposure to aerosol in a car with doors and windows closed, where the poultry were temporarily stored. It is necessary to promote centralized poultry slaughtering, cold chain distribution and fresh poultry sale, as well as strengthen health education and establish the concept of consuming fresh poultry.

[Relationship between red blood cell distribution width and left atrial appendage thrombogenic milieu in old patients with non-valvular atrial fibrillation].

Objective: To estimate the correlation between red cell distribution width (RDW) level and left atrial appendage thrombogenic milieu (LAATM) in elderly patients with non-valvular atrial fibrillation (NVAF). Methods: This was a retrospective case-control study. A total of 782 NVAF patients (age>60 years old) who finished transesophageal echocardiography (TEE) from January 2010 to December 2016 at Chaoyang Hospital was retrospectively screened, and diveded into LAATM group (n=65) and non LAATM group (n=717). RDW level was compared between the two groups. Potential association between RDW and LAATM was analyzed using multivariate logistic regression analysis. The accuracy of RDW for detecting LAATM was evaluated through receiver operating curve (ROC) analysis. Results: There were significant differences in age, history of heart failure, course of atrial fibrillation (AF), type of AF, NT-proBNP level, RDW level, left ventricular end systolic diameter, left ventricular end diastolic diameter, left ventricular ejection fraction (LVEF), left atrial diameter, CHADS(2) score and CHA(2)DS(2)-VASc score between the two groups (P<0.05). RDW level in LAATM group was significant higher than non LAATM group (13.4% (12.6%, 14.1%) vs. 12.1% (11.2%,13.0%), P<0.001). Multivariate logistic regression showed that RDW level associated with LAATM (OR=4.07, 95%CI 2.09-7.91, P<0.001). In ROC analysis, area under the curve was 0.81 (95%CI 0.74-0.88, P<0.001). When RDW level was 13.1%, LAATM could be diagnosed (sensitivity was 73.1% and specificity was 80.5%). Conclusions: RDW value is associated with the presence of LAATM in elderly NVAF patients. The RDW level has a certain reference value for predicting LAATM.

[The clinical significance of Th17 cells in patients with myelodysplastic syndrome and iron overload].

Objective: To study the significance of Th17 cells in patients with myelodysplastic syndrome (MDS) and iron overload. Methods: A total of 77 patients with MDS admitted to Guangzhou First People's Hospital were enrolled from January 2017 to December 2018,who were divided into iron overload group (37 cases) with serum ferritin (SF) over 1000 µg/L and non-ferrous overload group(40 cases). CD(4)(+)T cells in peripheral blood (PB) and bone marrow (BM) were sorted by flow cytometry. The ratio of Th17 cells and cells with abnormal karyotype were compared. IL-17 and IL-6 protein and RNA expression were detected by ELISA and quantitative real-time PCR(qRT-PCR). Results: The proportions of Th17 cells in PB and BM in iron overload group were significantly higher than those in non-iron overload group [(41.06±0.96)% vs. (26.80±1.21)%; (47.39±1.60)% vs. (34.29±1.03)%; P<0.01]. The Th17 positive cells with abnormal karyotype in iron overload group were more than those in non-iron overload group[(4.96±0.53)% vs. (3.67±0.12)% in PB; (10.06±1.67)% vs. (4.36±0.43)% in BM; P<0.01]. Similarly,the protein levels as well as mRNA expression of IL-6 and IL-17 in patients with iron overload were significantly higher than those in non-iron overload group (P<0.01 both in PB and BM). Conclusions: As hematopoietic regulators secreted by Th17 cells, the expression of IL-6 and IL-17 in MDS patients with iron overload are elevated. This may predict the influence of these factors to the differentiation of Th17 cells.

Aeromonas shuberti as a cause of multi-organ necrosis in internal organs of Nile tilapia, Oreochromis niloticus.

A disease with white spots in internal organs of Nile tilapia occurred in Zhanjiang, southern China. Multiple, white nodules, 0.8-2.2 mm in diameter, were scattered throughout the liver, spleen and kidney of diseased fish. Signs of nodules reproduced after artificial infection with the isolated strain. Isolated bacteria were Gram-negative, facultative anaerobic, motile, short rod-shaped, with a length of 1.2-2.2 µm. Morphological and biochemical tests, as well as phylogenetic analysis, all strongly indicated that the isolate from tilapia is identical to Aeromonas schubertii (A. schubertii) which temporary named LF1708 strain. Antibiotic sensitivity assays showed the LF1708 is sensitive to 24 of 27 tested antibiotics. Pathogenicity test revealed that the isolate at the dose of 3.75 × 106 CFU/g killed 100% of experimental tilapia within 2 days and the dose of 1 × 107 CFU/g killed 100% of experimental zebrafish within 1 day. Histopathology of diseased tilapia infected with A. schubertii showed numerous necrotic lesions widely distributed in spleen, liver and kidney, and infiltration with a large number of bacteria. To our knowledge, this was the first report that associated A. schubertii with mortality in tilapia.

[A case of human infection with highly pathogenic avian influenza A (H7N9) virus through poultry processing without protection measure].

Objective: To investigate the infection pattern and etiological characteristics of a case of human infection with highly pathogenic avian influenza A (H7N9) virus and provide evidence for the prevention and control of human infection with highly pathogenic avian influenza virus. Methods: Epidemiological investigation was conducted to explore the case's exposure history, infection route and disease progression. Samples collected from the patient, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (RT-PCR). Virus isolation, genome sequencing and phylogenetic analysis were conducted for positive samples. Results: The case had no live poultry contact history, but had a history of pulled chicken processing without taking protection measure in an unventilated kitchen before the onset. Samples collected from the patient's lower respiratory tract, the remaining frozen chicken meat and the live poultry market were all influenza A (H7N9) virus positive. The isolated viruses from these positive samples were highly homogenous. An insertion which lead to the addition of multiple basic amino acid residues (PEVPKRKRTAR/GL) was found at the HA cleavage site, suggesting that this virus might be highly pathogenic. Conclusions: Live poultry processing without protection measure is an important infection mode of "poultry to human" transmission of avian influenza viruses. Due to the limitation of protection measures in live poultry markets in Guangzhou, it is necessary to promote the standardized large scale poultry farming, the complete restriction of live poultry sales and centralized poultry slaughtering as well as ice fresh sale.

Transparent Tiger barb Puntius tetrazona, a fish model for in vivo analysis of nocardial infection.

Nocardiosis afflicts multiple species of cultured fish, resulting in substantial economic losses to the aquaculture industry, however, lack of detailed knowledge on disease pathogenesis has hampered the development of effective prevention and control strategies. In this study, we injected a green fluorescent protein (GFP)-labeled Nocardia seriolae strain into a transparent mutant strain of Tiger barb (Puntius tetrazona) to monitor tissue pathogen accumulation and tissue damage in vivo, and to clarify the relationship between pathogenic processes and overt symptoms. GFP-labeled bacteria were phagocytized by leukocytes and could proliferate within these cells, which in turn led to leukocyte aggregation, leukocyte death, and granuloma formation. In addition, intracellular bacteria could permanently colonize various tissues via leukocyte circulation, causing multi-organ infection as revealed by changes of tissue transparency. Histology revealed granulomatous lesions in organs such as muscle, kidney, and spleen that was corresponded to the tissue opacities in vivo. Confocal microscopy confirmed massive accumulations of GFP-labeled bacteria within these granulomas, which often contained a necrotic core. Tiger barb transparency allows for real-time observation of in vivo pathological changes within the same animal, and the pathogenic process can be evaluated based on the shape and size of body opacities. Thus, transparent Tiger barb is a promising model to study the pathogenesis of nocardiosis.

[The impact of different doses of atorvastatin on plasma endothelin and platelet function in acute ST-segment elevation myocardial infarction after emergency percutaneous coronary intervention].

Objective: To investigate the effects of different doses of atorvastatin on plasma endothelin and platelet function in acute ST-segment elevation myocardial infarction (STEMI) patients after emergency percutaneous coronary intervention(PCI). Methods: A total of 120 patients with acute STEMI treated with emergency PCI were enrolled and randomly divided into 20 mg of atorvastatin treatment group (standard group, n=60), and 40 mg of atorvastatin treatment group (intensive group, n=60). The blood C reactive protein (CRP), blood lipid profiles, plasma endothelin (ET) were measured before atorvastatin treatment and after 7 days of treatment, respectively. The platelet fibrin clot strength induced by ADP (MAADP) was determined by thrombelastography(TEG). Results: Seven days after of atorvastatin treatment, the level of plasma ET in intensive group was significantly lower than that in standard group [(0.49±0.21)pmol/L vs (0.63±0.58)pmol/L, P<0.05]. Moreover, the MAADP in intensive group was significantly decreased compared with the standard group [(38.4±17.4) mm vs (45.7±14.5) mm, P<0.05]. There was a positive correlation between the ET level and MAADP in intensive group after treatment (r=0.378, P<0.05). However, no significantly differences could be viewed in the CRP and LDL-C levels between the two groups (P>0.05). Conclusion: In patients with acute STEMI, early administration of 40 mg atorvastatin after emergency PCI could significantly reduce the vascular endothelial injury, improve endothelial function, and reduce the residual platelet activity.

[Epidemiological study on the relationship between the siesta and blood pressure].

OBJECTIVE: Use epidemiological approaches to investigate the correlation between the siesta and blood pressure. METHOD: From March 1(st,) 2011 to June 30(th) 2013, a total of 950 people were collected from East Jiaozhou Qingdao region using variable sampling methods including stratified method, the entire group method, random and proportional methods. Medical professionals conducted a person-to-person survey, collecting the data and inputting it into computers, after which a database was established using STATA 12.0. We analyzed the correlation between the siesta time and blood pressure/hypertension by using rank correlation method (Spearman). Logistic regression method was used to analyze the relationship between high blood pressure and different time and habit of the siesta after adjusting age, sex and BMI. RESULTS: There was a negative correlation between the time of siesta and the systolic pressure with r=-0.18, P<0.001; there was no relationship between the time of siesta and the diastolic pressure with r=-0.07, P=0.02; also, there is a negative correlation between the time of siesta and the hypertension morbidity, with r=-0.22, P<0.001. In the Logistic regression analysis about the period of time to take a nap and the risk of hypertension, it was found that the relative risk factors for hypertension were more than 60-year-old, BMI >25 kg/m(2) and no siesta habits. CONCLUSIONS: The time of siesta is negatively correlated to the systolic pressure, rather than the diastolic pressure, and it can generally reduce the incidence of hypertension. The relative risk factors of hypertension are more than 60-year-old, BMI >25 kg/m(2) and no siesta habits in all four seasons. We recommend that take a nap a day, or it might be even better for systolic blood pressure to take longer siesta.

Transmission of avian influenza A(H7N9) virus from father to child: a report of limited person-to-person transmission, Guangzhou, China, January 2014.

We investigated a possible person-to-person transmission within a family cluster of two confirmed influenza A(H7N9) patients in Guangzhou, China. The index case, a man in his late twenties, worked in a wet market that was confirmed to be contaminated by the influenza A(H7N9) virus. He developed a consistent fever and severe pneumonia after 4 January 2014. In contrast, the second case, his five-year-old child, who only developed a mild disease 10 days after disease onset of the index case, did not have any contact with poultry and birds but had unprotected and very close contact with the index case. The sequences of the haemagglutinin (HA) genes of the virus stains isolated from the two cases were 100% identical. These findings strongly suggest that the second case might have acquired the infection via transmission of the virus from the sick father. Fortunately, all 40 close contacts, including the other four family members who also had unprotected and very close contact with the cases, did not acquire influenza A(H7N9) virus infection, indicating that the person-to-person transmissibility of the virus remained limited. Our finding underlines the importance of carefully, thoroughly and punctually following-up close contacts of influenza A(H7N9) cases to allow detection of any secondary cases, as these may constitute an early warning signal of the virus's increasing ability to transmit from person-to-person.

Identification of a transparent mutant tiger barb Puntius tetrazona and its use for in vivo observation of a Pleistophora sp. (Microsporidia) infection.

A transparent mutant tiger barb Puntius tetrazona was identified and characterized by its transparent body, which allows clear visualization of internal organs. Hybridization of this mutant with the albino variant produces a transparent and albinoid double phenotype, and the transparency of this mutant is controlled by a recessive allele. Light microscopic and ultrastructural examinations show that in contrast to normal individuals, transparent mutants lack iridophores, and light penetrates unimpeded through the body. Pleistophora sp. infection was observed in vivo, allowing live observation of parasite dissemination and the consequent pathological alterations in the fish body as well as the simultaneous acquisition of data on the dynamics and spatial pattern of pathogenic invasion. It is superior to common fish models, as dynamic experimental data can be obtained from individual fish.

Distributed parallel processing for multidimensional maximum entropy reconstruction.

We have developed a two-dimensional maximum entropy spectrum reconstruction program designed to run in parallel on workstation clusters. Test reconstructions of planes extracted from a three-dimensional NMR data set indicate that the parallel speedup is nearly equal to the number of processors provided that the individual processors have comparable performance and that there are at least as many planes as processors. The program also works well in a typical laboratory setting consisting of heterogeneous workstations.

Automated resonance assignment of proteins using heteronuclear 3D NMR. 2. Side chain and sequence-specific assignment.

A sequential assignment protocol for proteins was developed using heteronuclear 3D NMR. The protocol consists of an amino acid type recognition algorithm and a primary sequence mapping algorithm. The former measures the similarity between each detected spin pattern and 20 standard amino acid coupling patterns. Both chemical shift and topologically likeness are considered. The mapping algorithm uses the amino acid type information to direct detected polypeptides to proper position onto protein primary sequence. The assignment protocol can be applied to spin systems generated by many different approaches. We designed a few computer programs to derive a protein's backbone and side chain spin systems using heteronuclear 3D NMR. The results was then input to the sequential assignment protocol. All of the algorithms were tested on NMR data of a 90-residue N-domain of chicken skeletal troponin-C.