Integrated bacterial transcriptome and host metabolome analysis reveals insights into "Candidatus Liberibacter asiaticus" population dynamics in the fruit pith of three citrus cultivars with different tolerance.

"Candidatus Liberibacter asiaticus" (CLas), the causal agent of citrus Huanglongbing (HLB), is able to multiply to a high abundance in citrus fruit pith. However, little is known about the biological processes and phytochemical substances that are vital for CLas colonization and growth in fruit pith. In this study, CLas-infected fruit pith of three citrus cultivars ("Shatangju" mandarin, "Guanxi" pomelo, and "Shatian" pomelo) exhibiting different tolerance to CLas were collected and used for dual RNA-Seq and untargeted metabolome analysis. Comparative transcriptome analysis found that the activation of the CLas noncyclic TCA pathway and pathogenic-related effectors could contribute to the colonization and growth of CLas in fruit pith. The pre-established Type 2 prophage in the CLas genome and the induction of its CRISPR/cas system could enhance the phage resistance of CLas and, in turn, facilitate CLas population growth in fruit pith. CLas infection caused the accumulation of amino acids that were correlated with tolerance to CLas. The accumulation of most sugars and organic acids in CLas-infected fruit pith, which could be due to the phloem blockage caused by CLas infection, was thought to be beneficial for CLas growth in localized phloem tissue. The higher levels of flavonoids and terpenoids in the fruit pith of CLas-tolerant cultivars, particularly those known for their antimicrobial properties, could hinder the growth of CLas. This study advances our understanding of CLas multiplication in fruit pith and offers novel insight into metabolites that could be responsible for tolerance to CLas or essential to CLas population growth.IMPORTANCECitrus Huanglongbing (HLB, also called citrus greening disease) is a highly destructive disease currently threatening citrus production worldwide. HLB is caused by an unculturable bacterial pathogen, "Candidatus Liberibacter asiaticus" (CLas). However, the mechanism of CLas colonization and growth in citrus hosts is poorly understood. In this study, we utilized the fruit pith tissue, which was able to maintain the CLas at a high abundance, as the materials for dual RNA-Seq and untargeted metabolome analysis, aiming to reveal the biological processes and phytochemical substances that are vital for CLas colonization and growth. We provided a genome-wide CLas transcriptome landscape in the fruit pith of three citrus cultivars with different tolerance and identified the important genes/pathways that contribute to CLas colonization and growth in the fruit pith. Metabolome profiling identified the key metabolites, which were mainly affected by CLas infection and influenced the population dynamic of CLas in fruit pith.

Preparation and strength formation mechanism of alkali-stimulated spontaneous combustion gangue-granulated blast furnace slag backfill.

Spontaneous combustion gangue (SCG) is often used as aggregate in traditional cemented paste backfill (CPB) for mine backfill, but the activation of SCG is insufficient. To stimulate the activity of SCG for the preparation of spontaneous combustion gangue-granulated blast furnace slag backfill (SGB), a new CPB was prepared by activating SCG via a mechanochemical composite activation method and adding ground granulated blast furnace slag (GGBS) to improve its activity. The mixing ratio was optimized by the response surface method and satisfaction function, and the strength formation mechanism was analyzed by scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR). The results showed that SCG had a certain pozzolanic activity, and the optimal grinding time was 30 min. The optimal mix ratio was 82.58% mass concentration, 2.93% alkali content, 30% GGBS content, and 52.92% fine gangue rate. Calcium silicate hydrate (C-S-H) gel and calcium aluminate sulfate hydrate (C-A-S-H) gel were the main reaction products of backfill, and with increasing curing age, C-S-H gel in the reaction system was gradually converted into C-A-S-H gel. FTIR analysis results showed that there were H-O-H, Si-O, and Si-O-T (T was Si or Al) bonds in the product, indicating that C-S-H gel and C-A-S-H gel were formed in the product. A new damage constitutive model was developed. The damage constitutive model could completely describe the backfill stress-strain curve. The study verified the feasibility of preparing cemented paste backfill with SCG and GGBS, which was beneficial to clean coal mine production and environmental protection.

Structure, variation and assembly of body-wide microbiomes in endangered crested ibis Nipponia nippon.

Limited knowledge of bird microbiome in the all-body niche hinders our understanding of host-microbial relationships and animal health. Here, we characterized the microbial composition of the crested ibis from 13 body sites, representing the cloaca, oral, feather and skin habitats, and explored assembly mechanism structuring the bacterial community of the four habitats respectively. The bacterial community characteristics were distinct among the four habitats. The skin harboured the highest alpha diversity and most diverse functions, followed by feather, oral and cloaca. Individual-specific features were observed when the skin and feathers were concentrated independently. Skin and feather samples of multiple body sites from the same individual were more similar than those from different individuals. Although a significant proportion of the microbiota in the host (85.7%-96.5%) was not derived from the environmental microbiome, as body sites became more exposed to the environment, the relative importance of neutral processes (random drift or dispersal) increased. Neutral processes were the most important contributor in shaping the feather microbiome communities (R2 = .859). A higher percentage of taxa (29.3%) on the skin were selected by hosts compared to taxa on other body habitats. This study demonstrated that niche speciation and partial neutral processes, rather than environmental sources, contribute to microbiome variation in the crested ibis. These results enhance our knowledge of baseline microbial diversity in birds and will aid health management in crested ibises in the future.

Inhibiting Coking of Lubricating Oil and Thermal Insulation of Bearing Chamber Wall by TCA-2 Nitride Ceramic Coating.

High temperature around the rear bearing chamber of supersonic aero-engines often causes the coking of the lubricating oil on the shaft end cover. To figure out the problem, a method using the TCA-2 nitride ceramic coating with the thickness of several micrometers is proposed. A simulation experiment method of lubricating oil coking for high-temperature parts is developed, and the anticoking performance of the samples with the coating is studied. The results showed that the TCA-2 coating inhibits the coke of lubricating oil on the metal surface within a certain temperature range by about 40.7% under the 500 °C attributed to the decrease in the surface activity of high-temperature metal and increase in the heat resistance. The TCA-2 coating also shows good compatibility with the lubricating oil since the acid value change of lubricating oil decreases after the thermal oxidation experiment. The TCA-2 coating can effectively reduce the surface temperature of the oil side.

[Carbon source metabolic diversity of soil microbial community under different climate types in the area affected by Wenchuan earthquake].

The MS8.0 Wenchuan earthquake in 2008 led to huge damage to land covers in northwest Sichuan, one of the critical fragile eco-regions in China which can be divided into Semi-arid dry hot climate zone (SDHC) and Subtropical humid monsoon climate zone (SHMC). Using the method of Bilog-ECO-microplate technique, this paper aimed to determine the functional diversity of soil microbial community in the earthquake-affected areas which can be divided into undamaged area (U), recover area (R) and damaged area without recovery (D) under different climate types, in order to provide scientific basis for ecological recovery. The results indicated that the average-well-color-development (AWCD) in undamaged area and recovery area showed SDHC > SHMC, which was contrary to the AWCD in the damaged area without recovery. The AWCD of damaged area without recovery was the lowest in both climate zones. The number of carbon source utilization types of soil microbial in SHMC zone was significantly higher than that in SDHC zone. The carbon source utilization types in both climate zones presented a trend of recover area > undamaged area > damaged area without recovery. The carbon source metabolic diversity characteristic of soil microbial community was significantly different in different climate zones. The diversity index and evenness index both showed a ranking of undamaged area > recover area > damaged area without recovery. In addition, the recovery area had the highest richness index. The soil microbial carbon sources metabolism characteristic was affected by soil nutrient, aboveground vegetation biomass and vegetation coverage to some extent. In conclusion, earthquake and its secondary disasters influenced the carbon source metabolic diversity characteristic of soil microbial community mainly through the change of aboveground vegetation and soil environmental factors.

[Framework design of MRI guided phased HIFU system and software development].

This paper introduced a new structure of MRI guided P-HIFU therapy system and software implementation based on the current P-HIFU system and interface provided by MRI vendor. The tests showed that the system's software can achieve the appropriate form of treatment need.

A method for protein extraction from different subcellular fractions of laticifer latex in Hevea brasiliensis compatible with 2-DE and MS.

BACKGROUND: Proteomic analysis of laticifer latex in Hevea brasiliensis has been received more significant attentions. However, the sticky and viscous characteristic of rubber latex as cytoplasm of laticifer cells and the complication of laticifer latex membrane systems has made it challenge to isolate high-quality proteins for 2-DE and MS. RESULTS: Based on the reported Borax/PVPP/Phenol (BPP) protocol, we developed an efficient method for protein preparation from different latex subcellular fractions and constructed high-resolution reference 2-DE maps. The obtained proteins from both total latex and C-serum fraction with this protocol generate more than one thousand protein spots and several hundreds of protein spots from rubber particles as well as lutoid fraction and its membranes on the CBB stained 2-DE gels. The identification of 13 representative proteins on 2-DE gels by MALDI TOF/TOF MS/MS suggested that this method is compatible with MS. CONCLUSION: The proteins extracted by this method are compatible with 2-DE and MS. This protein preparation protocol is expected to be used in future comparative proteomic analysis for natural rubber latex.