ASSVd infection inhibits the vegetative growth of apple trees by affecting leaf metabolism.

Apple scar skin viroid (ASSVd) can infect apple trees and cause scar skin symptoms. However, the associated physiological mechanisms are unclear in young saplings. In this study, ASSVd-infected and control 'Odysso' and 'Tonami' apple saplings were examined to clarify the effects of ASSVd on apple tree growth and physiological characteristics as well as the leaf metabolome. The results indicated that leaf ASSVd contents increased significantly after grafting and remained high in the second year. Leaf size, tree height, stem diameter, branch length, and leaf photosynthetic efficiency decreased significantly in viroid-infected saplings. In response to the ASSVd infection, the chlorophyll a and b contents decreased significantly in 'Odysso', but were unchanged in 'Tonami'. Moreover, the N, P, K, Fe, Mn, and Ca contents decreased significantly in the leaves of viroid-infected 'Odysso' or 'Tonami'. Similarly, the CAT and POD contents decreased significantly in the viroid-infected saplings, but the SOD content increased in the viroid-infected 'Tonami' saplings. A total of 15 and 40 differentially abundant metabolites were respectively identified in the metabolome analyses of 'Odysso' and 'Tonami' leaves. Specifically, in the viroid-infected 'Odysso' and 'Tonami' samples, the L-2-aminobutyric acid, 6″-O-malonyldaidzin, and D-xylose contents increased, while the coumarin content decreased. These metabolites are related to the biosynthesis of isoflavonoids and phenylpropanoids as well as the metabolism of carbohydrates and amino acids. These results imply that ASSVd affects apple sapling growth by affecting physiological characteristics and metabolism of apple leaves. The study data may be useful for future investigations on the physiological mechanisms underlying apple tree responses to ASSVd.

Changes in soil bacterial community and functions by substituting chemical fertilizer with biogas slurry in an apple orchard.

Growing concerns about the negative environmental effects of excessive chemical fertilizer input in fruit production have resulted in many attempts looking for adequate substitution. Biogas slurry as a representative organic fertilizer has the potential to replace chemical fertilizer for improvement of sustainability. However, it is still poorly known how biogas slurry applications may affect the composition of soil microbiome. Here, we investigated different substitution rates of chemical fertilizer with biogas slurry treatment (the control with no fertilizer and biogas slurry, CK; 100% chemical fertilizer, CF; biogas slurry replacing 50% of chemical fertilizer, CBS; and biogas slurry replacing 100% of chemical fertilizer, BS) in an apple orchard. Soil bacterial community and functional structure among treatments were determined using Illumina sequencing technology coupled with Functional Annotation of Prokaryotic Taxonomy (FAPROTAX) analysis. Leaf nutrient contents, apple fruit and soil parameters were used to assess plant and soil quality. Results showed that most of fruit parameters and soil properties were significantly varied in the four treatments. CBS treatment increased the contents of soil organic matter, alkali nitrogen and available potassium average by 49.8%, 40.7% and 27.9%, respectively. Treatments with biogas slurry application increased the single fruit weight, fresh weight, and dry weight of apple fruit average by 15.6%, 18.8% and 17.8, respectively. Soil bacterial community dominance and composition were significantly influenced by substituting of chemical fertilizer with biogas slurry. Biogas slurry application enhanced the relative abundance of some beneficial taxa (e.g. Acidobacteria Gp5 and Gp7, Parasegetibacter) and functional groups related to carbon and nitrogen cycling such as chemoheterotrophy, cellulolysis, and nitrogen fixation. Soil available phosphorus and potassium, pH and electrical conductivity were identified having a high potential for regulating soil bacterial specific taxa and functional groups. This study showed that the proper ratio application (50%: 50%) of biogas slurry with chemical fertilizer could regulate soil bacterial composition and functional structure via changes in soil nutrients. The variations of bacterial community could potentially take significant ecological roles in maintaining apple plant growth, soil fertility and functionality.

PPD results after 3-6 years of BCG vaccination and its effect on latent tuberculosis infection in children / 中国学校卫生

Objective@#To understand the results of tuberculin skin test (PPD) in preschool children after the vaccination of BCG, and to analyze the effect of BCG vaccination on latent tuberculosis infection in children.@*Methods@#From January to November 2018, a total of 1 359 preschool children from 14 kindergartens in 8 districts and cities of Jiangsu Province were selected for tuberculin test(PPD), and chest X-ray examination was performed on children with strong PPD results.@*Results@#The positive rate of PPD in preschool children in Jiangsu Province was 23.33%, of which strong positive and moderate positive (PPD≥10 mm) were totaled 6.47%. There were 149 boys (21.29%) with PPD positive reactions and 168 girls(25.50%) with PPD positive reactions, and differences of PPD positive reactions with different genders were of no statistical significance (χ2=3.36, P>0.05) And there were 201 children (25.35%) with PPD positive reactions in northern Jiangsu, 116 children (20.50%) with PPD positive reactions in southern Jiangsu. There were significant differences in the results of PPD positive and negative reactions between different regions(χ2=4.35, P<0.05). There was 1 case of PPD positive reactions among 3-year-old children(0.71%), 19 cases among 4-year-old children(3.89%), 31 cases among 5-year-old children(8.96%), and 37 cases among 6-year-old children(9.63%), and the differences of PPD positive reactions of different age groups were of statistical significance(χ2=21.69, P<0.01).@*Conclusion@#The positive rate of PPD in preschool children in Jiangsu Province is very low, indicating that PPD can be used as a detection method for latent infection in children. The overall positive rate of PPD in preschool children in Jiangsu Province is also low, and appropriate measures should be taken to protect susceptible children and effectively prevent and control childhood tuberculosis.

[Nasal mucosa remodeling in chronic rhinosinusitis without nasal polyps].

OBJECTIVE: To explore the feature of nasal mucosa remodeling in chronic rhinosinusitis without nasal polyps (CRSsNP). METHOD: Histological specimens from 30 selected patients with CRSsNP who underwent endoscopic sinus surgery and 10 control subjects were studied. The paraffin sections were stained with hematoxylin-eosin(HE), alcian blue-periodic acid-Schiff (AB-PAS), Masson trichrome (MT) and Picric acid-Sirius red. The damage of epithelium, goblet cells and gland hyperplasia, deposition of collagen in extracellular matrix, the thickness of basement membrane and the type of collagen were observed respectively. RESULT: Grade 0, Grade 1, Grade 2 and Grade 3 of epithelial damage were significantly different in the CRSsNP group when compared with the control group (P < 0.01 or P < 0.05). Evident mucus gland hyperplasia and collagen deposition in extracellular matrix were observed in CRSsNP group (P < 0.01). The number of goblet cells and the thickness of basement membrane were increased obviously in CRSsNP group (P < 0.01). The collagen deposited in extracellular matrix was mainly composed of collagen type I. Collagen type III and collagen type IV was much less than collagen type I. CONCLUSION: The nasal mucosa remodeling was observed in CRSsNP group and was characterized by epithelial damage, basement membrane thickening, deposition of collagen in extracellular matrix, goblet cells and mucus gland hyperplasia.

[Changes in amino acid and fatty acid contents as well as activity of some related enzymes in apple fruit during aroma production].

Aroma volatiles from apple (Malus domestica Borkh. var. Starkrimson) fruit at different stages of maturity were collected by solid adsorbent-Tenax-GC and determined by thermodesorption and GC-MS. Production of propyl acetate, butyl acetate, ethyl 2-methyl-butanoate and total ester volatiles and changes in concentration of the precursors of aroma biosynthsis--free amino acids and fatty acids and activities of lipoxygenases (LOX) and alcohol acetyltransferase (AAT) in apple fruits during ripening were studied. The results showed that propyl acetate and total esters were very low when the endogenous ethylene formation of the fruit was very low. At the stage of the increase in ethylene production, the rate of formation of propyl acetate and total esters increased. Butyl acetate appeared at the beginning of ethylene rise and increased thereafter. Ethyl 2-methyl-butanoate was produced at the beginning of climacteric stage and then increased sharply (Figs.1). These facts suggest that the aroma production is closely related to ethylene production. Among the 14 free amino acids detected in fruit, isoleucine which is considered to be the biosynthetic precursor of some branched chain esters showed a great increase during fruit ripening while the others decreased or remained stable (Table 1). The accumulation of isoleucine suggested that isoleucine supply in fruit may not limit the biosynthesis of esters with branched chain alkyl groups. Concentrations of free fatty acids such as palmitic, linolenic, oleic, linoleic, stearic acids increased before the increase of aroma production, decreased with the increase of aroma production and showed an increase at postclimacteric stages (Fig.2). LOX activity increased at climacteric stages and declined rapidly thereafter. AAT activity increased sharply at the early stage of fruit maturity when the aroma was very low and remained at a stable high level during fruit ripening (Fig.3) indicating that the AAT activity is not the limiting factor for aroma formation in apple fruit.