Isolation and characterization of distinctive pyrene-degrading bacteria from an uncontaminated soil.

Considerable efforts that isolate and characterize degrading bacteria for polycyclic aromatic hydrocarbons (PAHs) have focused on contaminated environments so far. Here we isolated three distinctive pyrene (PYR)-degrading bacteria from a paddy soil that was not contaminated with PAHs. These included a novel Bacillus sp. PyB-9 and efficient degraders, Shigella sp. PyB-6 and Agromyces sp. PyB-10. All three strains could utilize naphthalene, phenanthrene, anthracene, fluoranthene and PYR as sole carbon sources, and degraded PYR in a range of temperatures (27-37 °C) and pH (5-8). Strains PyB-6 and PyB-10 almost completely degraded 50 mg L-1 PYR within 15 days, and 75.5% and 98.9% of 100 mg L-1 PYR in 27 days, respectively. The kinetics of PYR biodegradation was well represented by the Gompertz model. Ten and twelve PYR metabolites were identified in PYR degradation process by strains PyB-6 and PyB-10, respectively. Chemical analyses demonstrated that the degradation mechanisms of PYR were the same for strains PyB-6 and PyB-10 with initial dioxygenation mainly on C-4,5 positions of PYR. The degradation of 4,5-phenanthrenedicarboxylic acid was branched to 4-phenanthrenecarboxylic acid pathway and 5-hydroxy-4-phenanthrenecarboxylic acid pathway, both of which played important roles in PYR degradation by strains PyB-6 and PyB-10. To our knowledge, Shigella sp. and Agromyces sp. were found for the first time to possess the capability for PAHs degradation. These findings contributed to upgrading the bank of microbial resource and knowledge on PAH biodegradation.

Feeding dietary fermentable fiber improved fecal microbial composition and increased acetic acid production in a nursery pig model.

The objective of this study was to determine the fermentable fiber (FF) content of several common fibrous ingredients fed to nursery pigs, and then evaluate the effect of dietary FF level on growth performance and fecal microbial composition. In experiment 1, 54 nursery pigs were randomly allotted to be fed nine diets with six replicate pigs per diet. Dietary treatments included a corn-soybean meal basal diet and eight test diets based on a mixture of the corn-soybean meal diet and corn distillers dried grains with solubles, sunflower meal, oat bran, wheat bran, corn bran, sugar beet pulp (SBP), apple pomace (AP) or soybean hulls (SH). In experiment 2, 180 nursery pigs were housed in 30 pens (six pigs per pen) and randomly allotted to be fed five diets with different FF to total dietary fiber (TDF) ratios, which were 0.52, 0.55, 0.58, 0.61, and 0.64, respectively. Results showed that the FF content in SBP, AP, and SH was greater (P < 0.01) than that in other ingredients. Water binding capacity of fibrous ingredients was positively correlated (P < 0.05) to the digestibility of TDF, acid detergent fiber, and non-starch polysaccharides in test ingredients. Pigs fed the SBP, AP and SH diets had greater (P < 0.05) fecal acetic acid and total short-chain fatty acids (SCFAs) concentrations compared with pigs fed other diets. Fecal acetic acid and total SCFAs concentrations were positively correlated (P < 0.05) with FF content in experimental diets. Average daily weight gain and average daily feed intake of pigs quadratically increased (P < 0.01) as the ratios of FF to TDF increased. Pigs in FF64% group showed higher (P < 0.05) ACE index and fecal acetic acid concentration compared with pigs fed the dietary FF/TDF ratio of 0.52 to 0.61. Compared with the classification system of soluble dietary fiber and insoluble dietary fiber, FF could better describe the mechanism by which dietary fiber has beneficial effects on pig gut health.

In nursery pigs, dietary fiber has received increasing attention because of its beneficial effects on the development and functional aspects of the gut. The most common physicochemical classification of dietary fiber is to divide it into two categories based on its solubility in water, as an indicator of its potential function and physiological effects in the gastrointestinal tract. Generally, soluble fiber, as the primary source of microbiota-derived short-chain fatty acids, is considered a useful predictor of the degree of microbial fermentation in the gut. Although fiber solubility may provide the first valuable information regarding physiological considerations of fermentability, it is not applicable to all fibrous ingredients, such as soluble carboxymethylcellulose, which is difficult to ferment. Therefore, this study aimed to determine the fermentable fiber (FF) content of several common fibrous ingredients fed to nursery pigs, and then evaluate the effect of dietary FF level on growth performance and fecal microbial composition of nursery pigs.

Research on the spatial correlation and formation mechanism between traditional villages and rural tourism.

In recent years, the survival and development of traditional villages in China have been serious challenges. Rural tourism is regarded as an important way to solve rural problems, and the combination of rural culture and tourism has become a new power point for rural development. Therefore, it is necessary to explore the spatial distribution structure between traditional villages and rural tourism. In this paper, rural tourism was represented by the rural tourism characteristic village (RTCV), and Henan Province, China, was taken as a study area to analyze the distribution pattern and spatial correlation of rural tourism and traditional village (TV) and discuss the relationship between the spatial correlation and regional natural environment and socioeconomic factors. The results show that the coupling of the spatial correlation between RTCVs and TVs in Henan was clear. They could be divided into 5 regions based on geographical factors. In addition, the research summarized 4 typical spatial structures between TVs and RTCVs in Henan based on the regional symbiosis theory, and the spatial pattern formation mechanism of TVs and RTCVs was discussed based on three driving mechanisms. The spatial structure of the two can provide reference value for other developing countries and regions to achieve sustainable rural development.

A variant of RAG1 gene identified in severe combined immunodeficiency: a case report.

BACKGROUND: The recombination-activating gene 1 (RAG1) protein is essential for the V (variable)-D (diversity)-J (joining) recombination process. Mutations in RAG1 have been reported to be associated with several types of immune disorders. Typical clinical features driven by RAG1 variants include persistent infections, severe lymphopenia, and decreased immunoglobulin levels . CASE PRESENTATION: In this study, a 2-month-24-days-old infant with recurrent fever was admitted to our hospital with multiple infections and absence of T and B lymphocytes. The infant was diagnosed with severe combined immunodeficiency (SCID). A homozygous variation c.2147G>A (NM_000448.2: exonme2: c.2147G>A (p.Arg716Gln)) was identified in the RAG1 gene using whole-exome sequencing and Sanger sequencing. The predicted 3D structure of variant RAG1 indicated altered protein stability. Additionally, decreased expression of variant RAG1 gene was detected at both the mRNA and protein levels. CONCLUSIONS: Our study identified a novel homozygous variant in RAG1 gene that causes SCID. This finding expands the variant spectrum of RAG1 in SCID and provides further evidence for the clinical diagnosis of SCID.

[Clinical application of blood purification in treatment of severe adenovirus pneumonia].

OBJECTIVE: To study the role of blood purification in the treatment of severe adenovirus pneumonia. METHODS: A total of 57 children with severe adenovirus pneumonia who underwent mechanical ventilation from February to June, 2019, were enrolled. According to whether blood purification was performed, they were divided into a purification group with 22 children and a conventional group with 35 children. Related clinical indices were collected, including duration of fever, duration of mechanical ventilation, length of stay in the intensive care unit (ICU), and mortality rate. The purification group was analyzed in terms of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) before blood purification and at 48 hours after blood purification, as well as stroke volume variation (SVV), thoracic fluid content (TFC), arterial partial pressure of oxygen/fraction of inhaled oxygen (P/F) value, and partial pressure of carbon dioxide (PCO2) before blood purification and at 6, 12, 24, and 48 hours after blood purification. RESULTS: Compared with the conventional group, the purification group had significantly shorter duration of fever, duration of mechanical ventilation, and length of stay in the ICU (P<0.05), and there was no significant difference in the mortality rate between the two groups (P>0.05). The purification group had significant reductions in IL-6 and TNF-α after blood purification, (P<0.05) and significant reductions in SVV and TFC at 12, 24, and 48 hours after blood purification (P<0.01), as well as a significant increase in P/F value and a significant reduction in PCO2 at 6, 12, 24, and 48 hours after blood purification (P<0.01). CONCLUSIONS: Blood purification as an auxiliary therapy can effectively improve the clinical symptoms of children with severe adenovirus pneumonia, and is thus an option for the treatment of severe adenovirus pneumonia in children.

[Clinical features of severe type 7 adenovirus pneumonia: an analysis of 45 cases].

OBJECTIVE: To study the clinical features of severe type 7 adenovirus pneumonia in children. METHODS: A retrospective analysis was performed for the clinical data of children who were diagnosed with severe type 7 adenovirus pneumonia from February to June, 2019. RESULTS: Among the 45 children, the male/female ratio was 3:2 and the median age was 14 months. All children had repeated fever, cough, and pulmonary moist rales, and the mean duration of fever was 14±4 days. The median time from fever to dyspnea was 8 days, and the time from fever to mechanical ventilation was 11.6±2.5 d. There was no significant increase in white blood cell count, with neutrophils as the main type. There were slight reductions in hemoglobin and albumin, while platelet and fibrinogen remained normal. There were increases in aspartate aminotransferase, lactate dehydrogenase, procalcitonin, and C-reaction protein. The detection rate of mixed pathogens was 84%. Effusion in both lungs was the major change on chest imaging (64%). Bronchoscopic manifestations were endobronchitis, tracheomalacia, and plastic bronchitis. The incidence rate of respiratory complications was 100%, and extrapulmonary complications mainly involved the circulatory system (47%), digestive system (36%), and nervous system (31%). Among the 45 children, 16 were administered with 400 mg/kg intravenous immunoglobulin (IVIG) daily for 5 days, with a mean duration of fever of 16±5 days, and 29 were administered with 1 g/kg IVIG daily for 2 days, with a mean duration of fever of 13±4 days; there was a significant difference in the mean duration of fever between the two groups (P=0.046). The overall mortality rate was 11%. CONCLUSIONS: Severe type 7 adenovirus pneumonia in children has severe conditions, with a high incidence rate of complications and a high mortality rate, so it should be diagnosed and treated as early as possible.

[Application of dexmedetomidine in children with agitation during ventilator weaning].

OBJECTIVE: To study the clinical effect and safety of dexmedetomidine in children with agitation during ventilator weaning. METHODS: A prospective open observational study was performed for children who were admitted to the intensive care unit and experienced mechanical ventilation between March 2017 and August 2018. They were given dexmedetomidine due to the failure in the spontaneous breathing test (SBT) caused by agitation. A sedation-agitation scale score of ≥5 was defined as agitation. The children were observed in terms of the sedation state at 0.5, 1, 2, 6, and 12 hours after the administration of dexmedetomidine, blood gas parameters before extubation and at 1, 24, and 48 hours after extubation, vital signs (heart rate, respiratory rate and mean arterial pressure) before SBT, before extubation, and at 10, 60, and 120 minutes and 24 hours after extubation, and incidence rates of adverse events related to the use of dexmedetomidine. RESULTS: A total of 19 children were enrolled in this study. All the children were in a state of agitation at the time of enrollment. At 0.5, 1, 2, 6, and 12 hours after the administration of dexmedetomidine, 12, 17, 17, 18, and 18 children respectively reached the sedation state. There were no significant differences in the oxygenation index, arterial partial pressure of carbon dioxide, heart rate, respiratory rate, and mean arterial pressure at each time point before and after extubation (P>0.05). No adverse events were observed, such as severe hypotension and respiratory depression, and only one child experienced reversible bradycardia. CONCLUSIONS: Dexmedetomidine is safe and effective in children with agitation during ventilator weaning, but prospective randomized controlled trials are needed for verification.

Prognostic Value of B-Type Natriuretic Peptide, Leukocytosis, and Hyperglycemia in Children with Severe Hand, Foot, and Mouth Disease.

OBJECTIVE: Our goal is to determine the prognostic value of serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP), leukocytosis, and hyperglycemia in patients with severe hand, foot, and mouth disease (HFMD). DESIGN: This is a prospective cohort study conducted from March 2011 through October 2012 at Hunan Children's Hospital. SETTING: Hunan Children's Hospital, a large children's teaching hospital with 1,500-beds located in the Changsha region of Hunan Province in China. PATIENTS: 295 children who were presented with clinical manifestation of severe HFMD, and required hospitalization. INTERVENTIONS: Standard supportive treatment for HFMD as recommended by the national guidelines. MEASUREMENTS: Admission blood samples were analyzed for NT-proBNP, leukocyte count, and serum glucose. Independent prognostic value of NT-proBNP for predicting mortality was evaluated using the Cox proportional hazard model adjusting for various covariates. MAIN RESULTS: Area under the curve of receiver operating characteristic (AUROC) analysis suggested that a serum concentration of NT-proBNP concentration more than 1,500 pg/mL is an optimal cutoff point. Twenty-four patients (8.1%) had an NT-proBNP more than 1,500 pg/mL, and a 3-day mortality of 46% (11/24). Adjusted for tachycardia, tachypnea, hypertension, hyperglycemia, leukocytosis, and conscious disturbance on presentation, elevated NT-proBNP was associated with a 22.5-fold (95% confidence interval, 3.56-142.66) increased risk of 3-day mortality. We have further improved the specificity and AUROC values by the HFMD laboratory score, which combines NT-proBNP, leukocytosis, and hyperglycemia. CONCLUSIONS: Routine admission surveillance for NT-proBNP is useful for identifying patients with HFMD at risk for mortality. Further studies are needed to determine whether early intervention in patients with highly elevated NT-proBNP can improve outcome.

Diagnostic value of serum procalcitonin in patients with chronic renal insufficiency: a systematic review and meta-analysis.

BACKGROUND: The diagnostic value of procalcitonin (PCT) for patients with renal impairment is unclear. METHODS: We searched multiple databases for studies published through December 2011 that evaluated the diagnostic performance of PCT among patients with renal impairment and suspected systemic bacterial infection. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effects models. RESULTS: Our search identified 201 citations, of which seven diagnostic studies evaluated 803 patients and 255 bacterial infection episodes. HSROC-bivariate pooled sensitivity estimates were 73% [95% confidence interval (95% CI) 54-86%] for PCT tests and 78% (95% CI 52-92%) for CRP tests. Pooled specificity estimates were higher for both PCT and CRP tests [PCT, 88% (95% CI 79-93%); CRP, 84% (95% CI, 52-96%)]. The positive likelihood ratio for PCT [likelihood (LR)+ 6.02, 95% CI 3.16-11.47] was sufficiently high to be qualified as a rule-in diagnostic tool, while the negative likelihood ratio was not low enough to be used as a rule-out diagnostic tool (LR- 0.31, 95% CI 0.17-0.57). There was no consistent evidence that PCT was more accurate than CRP test for the diagnosis of systemic infection among patients with renal impairment. CONCLUSIONS: Both PCT and CRP tests have poor sensitivity but acceptable specificity in diagnosing bacterial infection among patients with renal impairment. Given the poor negative likelihood ratio, its role as a rule-out test is questionable.

[Effects of ketamine and alcohol on learning and memory impairment in mice].

OBJECTIVE: To study the effects of ketamine and alcohol on learning and memory in mice and its possible mechanism. METHODS: Forty mice were divided into 4 groups: normal control group, ketamine group, alcohol group, and alcohol plus ketamine group. Ketamine and alcohol were given by intraperitoneal injection and intragastric administration, respectively, 1 time per day, for 14 days. The ability of learning and memory in mice was tested by the method of step-down and Morris water maze. Acetylcholine (ACh) and 5-hydroxy tryptamine(5-HT) in mice brain tissue were analyzed for the possible mechanism. RESULTS: (1) Step-down: The treatment groups lessened the latency and added wrong times (P < 0.05). The number of errors in the combined treatment group significantly increased comparing with the single drug treatment group (P < 0.05). (2) Morris water-maze: The treatment groups prolonged the latency (P < 0.05), reduced the target quadrant activity time significantly (P < 0.05), and decreased the numbers of crossing the former platform significantly (P < 0.05). (3) Biochemical index determination: The concentrations of ACh and 5-HT in treatment groups decreased significantly (P < 0.05), showed a more decreasement comparing with the single drug treatment group. CONCLUSION: Ketamine has a synergistic effect with alcohol on learning and memory impairment in mice, which may be related to the common inhibitive effect on the ACh and 5-HT.

Differentiation between infectious and noninfectious ulcerative keratitis by Raman spectra of human teardrops: a pilot study.

PURPOSE: The aim of this study was to use Raman spectra of tears to differentiate between infectious and noninfectious ulcerative keratitis. METHODS: Raman microspectroscopy was applied using the drop-coating deposition method on Ti/Au-coated glass slides to obtain sample spectra from different human tear groups, including tears from healthy subjects and from patients with infectious and noninfectious ulcerative keratitis. By comparing the difference spectra of the groups, the authors identified local Raman features useful for differentiation of ulcerative keratitis. Principal components (PCs) of normal tears were used as affined spectral coordinates. After performing projections of Raman spectra of both infectious and noninfectious tear samples, the authors compared the two groups to identify global spectral parameters with differential statistical significance. RESULTS: Differentiation between infectious and noninfectious ulcerative keratitis might be made directly through observation of the normalized tear Raman spectra or the transformed principal scores. Spectral segments with differential statistical significance included 878∼888 cm(-1), 885∼888 cm(-1), 945∼993 cm(-1), 1007∼1015 cm(-1), 1074∼1100 cm(-1), 1090∼1094 cm(-1), 1096∼1099 cm(-1), 1386∼1403 cm(-1), 1463∼1469 cm(-1), 1469∼1473 cm(-1), 1557∼1563 cm(-1), 1584∼1588 cm(-1), and 1614∼1621 cm(-1). There were two PCs with statistically significant differences for the two groups of ulcerative keratitis, PC1 (P = 0.01) and PC2 (P = 0.05). CONCLUSIONS: This novel approach using the analysis of Raman spectra of teardrop samples for differentiation of ulcerative keratitis demonstrates the potential application of Raman microspectroscopy for clinical practice. This technology should complement the conventional cytological method for rapid diagnosis in the clinician's office.