[Investigation on cognition, diagnosis and treatment status of chest tightness variant asthma among Chinese pediatricians].

Objective: To evaluate the awareness, diagnosis and treatment of chest tightness variant asthma (CTVA) among pediatricians in China. Methods: The survey was conducted by convenient sampling method. Pediatricians with professional title of attending physician and above from different grades hospitals in 30 provinces were invited to conduct online questionnaire surveys through WeChat, pediatricians scan QR codes to complete electronic questionnaires in the mini program from January 16th to February 4th, 2021. The contents of questionnaire included the awareness, diagnosis and treatment of CTVA, and comparing the differences between pediatricians in secondary hospitals and tertiary hospitals. Results: A total of 1 529 pediatricians participated in the survey, and 1 484 (97.06%) pediatricians completed the questionnaire and included in the analysis, including 420 males (28.30%). The awareness rate of CTVA among pediatricians was 77.83 % (1 155/1 484). Pediatricians in tertiary hospitals had higher rates of awareness of CTVA than pediatricians in secondary hospitals [81.86% (898/1 097) vs 66.41% (257/387), P<0.001] and had better execution of the guidelines [89.15% (978/1 097) vs 79.59% (308/387), P<0.001]. A total of 93.06 % (1 381/1 484) of pediatricians' first-line treatment included inhaled corticosteroids (ICS) for CTVA. Among them, a higher proportion of pediatricians in tertiary hospitals used ICS included regimens for first-line treatment of CTVA compared with pediatricians in secondary hospitals [94.90% (1 041/1 097) vs 87.86% (340/387), P<0.001]. The reported well control rate of CTVA was 32.08% (476/1 484), which was significantly lower in secondary hospitals than that in tertiary hospitals [17.31% (67/387) vs 37.28% (409/1 097), P<0.001]. Conclusion: Most pediatricians are well aware of CTVA, among which there is a certain gap in clinical practice between pediatricians in secondary hospitals and tertiary hospitals in terms of understanding, diagnosis, and treatment of CTVA.

[A multicenter retrospective study on the etiology of necrotizing pneumonia in children].

Objective: To investigate the etiology of necrotizing pneumonia (NP) in children and the clinical characteristics of NP caused by different pathogens in China. Methods: A retrospective, case-control study was performed in children with NP who were admitted to 13 hospitals in China from January 2008 to December 2019. The demographic and clinical information, laboratory data, etiological and radiological findings were analyzed. The data were divided into three groups based on the following years: 2008-2011, 2012-2015 and 2016-2019, and the distribution characteristics of the pathogens in different period were compared. Meanwhile, the pathogens of pediatric NP in the southern and northern China were compared. And the clinical characteristics of the Mycoplasma pneumoniae (MP) NP and the bacterial NP were also compared. T-test or Mann-Whitney nonparametric test was used for comparison of numerical variables, and χ2 test was used for categorical variables. Results: A total of 494 children with NP were enrolled, the median ages were 4.7 (0.1-15.3) years, including 272 boys and 222 girls. Among these patients, pathogens were identified in 347 cases and the pathogen was unclear in the remaining 147 cases. The main pathogens were MP (238 cases), Streptococcus pneumoniae (SP) (61 cases), Staphylococcus aureus (SA) (51 cases), Pseudomonas aeruginosa (13 cases), Haemophilus influenzae (10 cases), adenovirus (10 cases), and influenza virus A (7 cases), respectively. MP was the most common pathogen in all three periods and the proportion increased yearly. The proportion of MP in 2016-2019 was significantly higher than that in 2012-2015 (52.1% (197/378) vs. 36.8% (32/87), χ2=6.654, P=0.010), while there was no significant difference in the proportion of MP in 2012-2015 and that in 2008-2011 (36.8% (32/87) vs. 31.0% (9/29), χ²=0.314, P=0.575).Regarding the regional distribution, 342 cases were in the southern China and 152 in the northern China. Also, MP was the most common pathogen in both regions, but the proportion of MP was higher and the proportion of SP was lower in the north than those in the south (60.5% (92/152) vs. 42.7% (146/342), χ2=13.409, P<0.010; 7.9% (12/152) vs. 14.3% (49/342), χ2=4.023, P=0.045). Comparing the clinical characteristics of different pathogens, we found that fever and cough were the common symptoms in both single MP and single bacterial groups, but chest pain was more common (17.0% (34/200) vs. 6.1% (6/98), χ2=6.697, P=0.010) while shortness of breath and wheezing were less common in MP group (16.0% (32/200) vs. 60.2% (59/98), χ2=60.688, P<0.01; 4.5% (9/200) vs. 21.4% (21/98), χ2=20.819, P<0.01, respectively). The white blood cell count, C-reactive protein and procalcitonin in the bacterial group were significantly higher than those in the MP group (14.7 (1.0-67.1)×109/L vs. 10.5 (2.5-32.2)×109/L, 122.5 (0.5-277.3) mg/L vs. 51.4 (0.5-200.0) g/L, 2.13 (0.05-100.00) µg/L vs. 0.24 (0.01-18.85) µg/L, Z=-3.719, -5.901 and -7.765, all P<0.01). Conclusions: The prevalence of pediatric NP in China shows an increasing trend during the past years. MP, SP and SA are the main pathogens of NP, and the most common clinical symptoms are fever and cough. The WBC count, C-reactive protein and procalcitonin in bacterial NP are significantly higher than those caused by MP.

[Genetic variants in the surfactant protein C gene 218 site are associated with pediatric interstitial lung disease: seven cases study].

Objective: To investigate the clinical features and outcomes of pulmonary surfactant protein C gene (SFTPC) 218 site mutation in children with pulmonary interstitial disease. Methods: In this retrospective study, the clinical data, outcomes and influencing factors of 7 cases of SFTPC gene 218 site mutations in infants with interstitial lung disease in three hospitals from January 2013 to December 2016 were analyzed. Results: Seven cases were full-term children, 4 cases had the onset within 3 months after birth, 2 cases after 1 year old, 1 case within 3 months to 1 year, clinical manifestations of these cases were cough, shortness of breath, dyspnea, and limited growth and development, could not maintain life without additional oxygen supplementation, blood gas analysis showed hypoxemia, 4 cases had clubbing. Chest CT showed diffuse ground glass-like change in both lungs. Three cases were positive for cytomegalovirus (CMV)-IgM or CMV-DNA. The mutations in 7 cases were exon 3, 5 of which were SFTPC gene c.218T>C, p.lle73Thr (heterozygous mutation), and 2 cases were SFTPC gene c.218T>A, p.lle73Asn (homozygous mutation), 1 case combined with ABCA3 gene mutations. Four patients were treated with prednisone alone, one with prednisone plus hydroxychloroquine, and two with symptomatic treatment. Three patients died, 3 patients improved, and 1 patient was lost to follow-up. Conclusions: The severity and prognosis of the children with SP-C 218 site mutation may be affected by many factors. Some children who received glucocorticoid alone do not have a good response.

Xylan utilization regulon in Xanthomonas citri pv. citri Strain 306: gene expression and utilization of oligoxylosides.

Xanthomonas citri pv. citri strain 306 (Xcc306), a causative agent of citrus canker, produces endoxylanases that catalyze the depolymerization of cell wall-associated xylans. In the sequenced genomes of all plant-pathogenic xanthomonads, genes encoding xylanolytic enzymes are clustered in three adjacent operons. In Xcc306, these consecutive operons contain genes encoding the glycoside hydrolase family 10 (GH10) endoxylanases Xyn10A and Xyn10C, the agu67 gene, encoding a GH67 α-glucuronidase (Agu67), the xyn43E gene, encoding a putative GH43 α-l-arabinofuranosidase, and the xyn43F gene, encoding a putative ß-xylosidase. Recombinant Xyn10A and Xyn10C convert polymeric 4-O-methylglucuronoxylan (MeGXn) to oligoxylosides methylglucuronoxylotriose (MeGX3), xylotriose (X3), and xylobiose (X2). Xcc306 completely utilizes MeGXn predigested with Xyn10A or Xyn10C but shows little utilization of MeGXn. Xcc306 with a deletion in the gene encoding α-glucuronidase (Xcc306 Δagu67) will not utilize MeGX3 for growth, demonstrating the role of Agu67 in the complete utilization of GH10-digested MeGXn. Preferential growth on oligoxylosides compared to growth on polymeric MeGXn indicates that GH10 xylanases, either secreted by Xcc306 in planta or produced by the plant host, generate oligoxylosides that are processed by Xyn10 xylanases and Agu67 residing in the periplasm. Coordinate induction by oligoxylosides of xyn10, agu67, cirA, the tonB receptor, and other genes within these three operons indicates that they constitute a regulon that is responsive to the oligoxylosides generated by the action of Xcc306 GH10 xylanases on MeGXn. The combined expression of genes in this regulon may allow scavenging of oligoxylosides derived from cell wall deconstruction, thereby contributing to the tissue colonization and/or survival of Xcc306 and, ultimately, to plant disease.

'Candidatus Pasteuria aldrichii', an obligate endoparasite of the bacterivorous nematode Bursilla.

A novel bacterium of the genus Pasteuria was discovered parasitizing bacterivorous nematodes of the genus Bursilla, in selected bermudagrass (Cynodon) field plots in Davie, FL, USA. Soil containing this bacterium was sampled and supplied with bi-weekly inoculations of cultured species of the genus Bursilla in order to build and maintain a source of endospores for continuous in vivo conservation of the bacteria for further study and characterization. 16S rRNA gene sequence similarities supported its congeneric ranking with other members of the genus Pasteuria that have been identified from nematodes and cladocerans. There were, however, no clear sister candidates for this organism, which supported the evidence of endospore ultrastructure and host-range studies, suggesting it belonged to a novel taxon. Because members of the genus Pasteuria cannot yet be isolated, definitive type strains could not be maintained; therefore, the name 'Candidatus Pasteuria aldrichii' is proposed for this organism.

Airway neutrophilia in COPD is not associated with increased neutrophil survival.

Neutrophilic airway inflammation is a prominent feature of chronic obstructive pulmonary disease (COPD) and correlates with disease severity. The mechanisms that determine the extent of neutrophilia could involve increased influx or prolonged survival of neutrophils. The aim of the study was to assess whether neutrophil pro-survival mechanisms are increased in the airways of subjects with COPD owing to the presence of anti-apoptotic factors in the bronchial lining fluid. Induced sputum samples were collected from 20 subjects with stable COPD, 14 healthy smokers and 14 healthy controls. Quantification of apoptotic neutrophils was based on typical morphological cell changes. Anti-apoptotic, pro-survival activity in the sputum was studied by culturing peripheral blood neutrophils with the fluid phase of induced sputum. Apoptosis was assessed both by morphology and flow cytometry using Annexin V/7-aminoactinomycin D staining. COPD patients and healthy smokers had significantly higher percentages of sputum neutrophils than healthy controls. However, there were no significant differences between the three subject groups in either the proportion of apoptotic neutrophils in sputum or the in vitro anti-apoptotic activity detected in the sputum fluid phase. In conclusion, prolonged survival of neutrophils in sputum is not a feature of chronic obstructive pulmonary disease and cannot explain the increased numbers of airway neutrophils in this disease.

Detection of Pasteuria penetrans infection in Meloidogyne arenaria race 1 in planta by polymerase chain reaction.

We report on the development of a PCR-based assay to detect Pasteuria penetrans infection of Meloidogyne arenaria in planta using specific primers for recently sequenced sigE, spoIIAB and atpF genes of P. penetrans biotype P20. Amplification of these genes in crude DNA extracts of ground tomato root galls using real-time kinetic PCR distinguished infected from uninfected M. arenaria race 1 by analysis of consensus thresholds for single copy genes. Fluorescent in situ hybridization (FISH) using the sigE primer sequence as a probe shows hybridization to P. penetrans cells in various stages of vegetative (pre-endospore) development. Ratios of gene copies for sigE and 16S rDNA were obtained for P. penetrans and compared to Bacillus subtilis as a genomic paradigm of endospore-forming bacteria. Phylogenetic analysis of the sigE gene from Gram-positive, endospore-forming bacteria finds P. penetrans most closely related Paenbacillus polymyxa. The sporulation genes (spo genes), particularly sigE, have sequence diversity that recommends them for species and biotype differentiation of the numerous Pasteuria isolates that infect a large number of plant-parasitic nematodes.

Pasteuria spp.: Systematics and Phylogeny of These Bacterial Parasites of Phytopathogenic Nematodes.

Pasteuria spp. include endospore-forming bacterial pathogens of cladoceran crustaceans and plant-parasitic nematodes. Propagation of these nematode pathogens requires attachment of soilborne endospores to nematode hosts, infection, growth, sporulation, and release of endospores to repeat the cycle of infection and propagation. The ability of these bacteria to suppress the levels of plant-parasitic nematodes in the field has made them particularly promising candidates for biocontrol of nematode diseases of plants. Genes encoding 16S ribosomal RNA have been sequenced for the cladoceran (water flea) parasite and type species, Pasteuria ramosa, and for Pasteuria spp. isolated from root-knot (Meloidogyne arenaria race 1 and Meloidogyne sp.), soybean cyst (Heterodera glycines), and sting (Belonolaimus longicaudatus) nematodes. These have provided a phylogenetic basis for their designation to a distinct clade within the family Alicyclobacillaceae of the gram-positive endospore-forming bacteria. Two apparent biotypes of P. penetrans demonstrating a host preference for different Meloidogyne spp. showed identical 16S rDNA sequences, suggesting host-recognition evolves within a given species. The sequences of genes encoding sporulation transcription factors, sigE and sigF, from P. penetrans biotype P-20 show different phylogenetic relationships to other endospore-forming bacteria, supporting their application to further discriminate Pasteuria spp. and biotypes. Distribution of an adhesin-associated epitope on polypeptides from different Pasteuria isolates provides an immunochemical approach to differentiate species and biotypes with specific host preferences. Application of bioinformatics to genomic data, as well as further characterization of the biochemical basis for host recognition, will facilitate development of Pasteuria spp. as benign alternatives to chemical nematicides.

Molecular cloning of a teleost growth hormone receptor and its functional interaction with human growth hormone.

This paper reports the first full-length cDNA sequence of a growth hormone receptor (GHR) from a teleost fish and its functional expression in cultured eukaryotic cells. The cDNA sequence, from Carassius auratus (goldfish), encodes a protein of 602 amino acids (aa) akin in architecture to the GHRs of other species. Despite the presence of motifs characteristic of GHR, the overall homology between the goldfish GHR and other GHRs is very low ( approximately 40% aa identity). CHO cells transfected with this receptor cDNA can be stimulated to proliferate by human growth hormone (hGH). In addition, the transfected cells can transactivate a co-expressed mammalian serine protease inhibitor (Spi) 2.1 promoter upon stimulation by hGH, indicating the successful interaction of the fish receptor with the mammalian ligand to evoke the down-stream post-receptor events. Tissue distribution studies indicated that the receptor is mostly expressed in the liver and hypothalamus of goldfish. A single mRNA transcript of a size of about 4 kb was found in the goldfish liver.

[The identification of BmNPV gp64 envelope gene].

gp64 glycoprotein, an abundant and the only membrane glycoprotein encoded by the baculovirus genome, contains a signal peptide sequence at N-terminus, a transmembrane anchor at c-terminus and a ectodomain between them. The efficient signal sequences and the transmembrane anchor sequences of AcMNPV gp64 gene have been exploited in baculovirus expression system. Using 1.3 kb AcMNPV gp64 gene coding sequence as the probe, the nucleotide sequence of BmNPV gp64 gene was determined, and a 1530 nucleotide open reading frame flanked by an AT-rich sequence was identified that could encode a polypeptide with 509 amino acid residues. Computer analysis indicated BmNPV gp64 gene is 84.3% identical to AcMNPV at the level of nucleotide sequence and 94.7% identical at the level of predicted amino acid sequence.

Characterization of the ecdysteroid UDP-glucosyltransferase gene of Spodoptera litura multinucleocapsid nucleopolyhedrovirus.

The ecdysteroid UDP-glucosyltransferase (EGT) gene of Spodoptera litura multinucleocapsid nucleopolyhedrovirus (SpltMNPV), Guangzhouisolate was sequenced. The open reading frame of the gene is 1530 nucleotides long, encoding a putative protein of 509 amino acids with Mr of 58,500. The 5' noncoding region has a TATA box. A polyadenylation signal, AATAAA, is contained downstream of the translation stop codon. A putative signal peptide is present at the N-terminus of the protein. Homology comparison with other baculovirus egt genes showed that these genes are highly conserved. The SpltMNPV egt gene is closely related to that of Spodoptera littoralis nucleopolyhedrovirus (SliNPV) with the identities of 84% in nucleotide and 91% in amino acid, respectively. In this study, an alignment of amino acid sequences has been made and a tentative phylogenetic tree of twelve baculovirus egts is presented.

[Cloning and analysis of the regulatory gene fragment induced with seed extract in Rhizobium huakuii strain 7653R].

The large plasmids of strain 7653R were digested with restriction enzyme EcoRI. Their DNA fragments were cloned into the expression vector pMP220 to construct a lacZ fusion pool, which were transferred into the recipient strain 7653R. Tri-transconjugants were selected onto plates containing X-gal and seed extract. Five blue colonies were assayed of their beta-galactosidase activity after incubation with or without seed extract. A positive induced strain HN18 was obtained. Hybridization of nodDABC probe on the recombinant plasmid pHN18 showed a 1.7 kb positive band. The evidence makes a deduction that the pHN18 contains a promoter of nod operon.