Search

Background Huanglongbing (HLB) or citrus greening is a devastating disease of citrus. The gram-negative bacterium Candidatus Liberibacter asiaticus (Las) belonging to the α-proteobacteria is responsible for HLB in North America as well as in Asia. Currently, there is no cure for this disease. Early detection and quarantine of Las-infected trees are important management strategies used to prevent HLB from invading HLB-free citrus producing regions. Quantitative real-time PCR (qRT-PCR) based molecular diagnostic assays have been routinely used in the detection and diagnosis of Las. The oligonucleotide primer pairs based on conserved genes or regions, which include 16S rDNA and the β-operon, have been widely employed in the detection of Las by qRT-PCR. The availability of whole genome sequence of Las now allows the design of primers beyond the conserved regions for the detection of Las explicitly. Results We took a complimentary approach by systematically screening the genes in a genome-wide fashion, to identify the unique signatures that are only present in Las by an exhaustive sequence based similarity search against the nucleotide sequence database. Our search resulted in 34 probable unique signatures. Furthermore, by designing the primer pair specific to the identified signatures, we showed that most of our primer sets are able to detect Las from the infected plant and psyllid materials collected from the USA and China by qRT-PCR. Overall, 18 primer pairs of the 34 are found to be highly specific to Las with no cross reactivity to the closely related species Ca. L. americanus (Lam) and Ca. L. africanus (Laf). Conclusions We have designed qRT-PCR primers based on Las specific genes. Among them, 18 are suitable for the detection of Las from Las-infected plant and psyllid samples. The repertoire of primers that we have developed and characterized in this study enhanced the qRT-PCR based molecular diagnosis of HLB. [ABSTRACT FROM AUTHOR]

Names of body parts have an extremely important value not only in historical linguistics, but also in grammar of which they are the cognitive basis. Some of the concept of spatial orientation is the result of extension of body-parts. Similarly, many names of things have a relationship with names of body-parts. By examining words of spatial orientation and time, we conclude that Hakka has "zoomorphic model" and "anthropomorphic model" in space and time cognition, but She used "human model" and "astronomical reference" to understand the spatial orientation, and we also found that there are some problems in studying etymology. By examining some of the names of things, we identified that there are many similarities when She and the Hakka naming things. They are guided by these mechanisms--" Top-down strategy ", " Part-to-whole strategy " and sometimes refer to the shape of things, character, function and other factors. We point out that the classification and the naming of things of Hakka is different from the nomenclature and classification of systematic biology. It is influenced by traditional culture, following indigenous mechanisms in classification and naming of things. There are similarities and differences of the cognitive models obtained by studying body-part names of Hakka and She. They reflected the same characteristics and also unique features of cognition of human beings. The unique features confirm the "Sapir - Whorf Hypothesis". [ABSTRACT FROM AUTHOR]

Background: Haff disease is unexplained rhabdomyolysis caused by consumption of fishery products in the previous 24 h. It was first identified in Europe in 1924 but the condition is extremely rare in China. Here we describe a past outbreak of acute food borne muscle poisoning that occurred in Guangdong Province (South China) in 2009. Methods: The first full outbreak of Haff disease reported in Jiangsu Province (East China) in 2010, indicated that the incidence of the disease may be increasing in China. We, therefore first retrospectively reviewed epidemiologic, trace-back, environmental studies, and laboratory analyses, including oral toxicity testing to ascertain risk and chemical analysis to identify toxin(s), from the 2009 Guangdong outbreak. Then we compared data from the 2009 outbreak with data from all other Haff disease outbreaks that were available. Results: Clinical symptoms and laboratory findings indicated that the 2009 Guangdong outbreak disease was consistent with rhabdomyolysis. Epidemiologic, trace-back, environmental studies and laboratory analyses implied that the disease was caused by freshwater Pomfrets consumed prior to the onset of symptoms. We also identified common factors between the 2009 Guangdong outbreak and previous Haff disease outbreaks reported around the world, while as with other similar outbreaks, the exact etiological factor(s) of the disease remains unknown. Conclusions: The 2009 Guangdong outbreak of 'muscle poisoning' was retrospectively identified as an outbreak of Haff disease. This comprised the highest number of cases reported in China thus far. Food borne diseases emerging in this unusual form and the irregular pattern of outbreaks present an ongoing public health risk, highlighting the need for improved surveillance and diagnostic methodology. [ABSTRACT FROM AUTHOR]

The article discusses a study which confirmed that 15 serovars and diverse genotypes of Haemophilus parasuis were widely distributed in southern China. A total of 112 H. parasuis strains were subjected to serovar analysis by gel diffusion (GD) and indirect hemagglutination (IHA) tests and to genotype analysis by means of pulse-field gel electrophoresis (PFGE). The study found that the 23 nontypeable strains showed 22 different PFGE profiles.

Pure and Ta-doped barium titanate hafnate (BaHf01Ti09O3, short for BHT) ceramics were prepared by conventional solid state reaction method. The microstructures and ferroelectric properties of BaHf0.1Ti0.9-xTax03 (x = 0, 0.005, 0.01, 0.015, 0.02) ceramics have been investigated. From the x-ray diffraction patterns it is indicated that Ta5+ ions have entered the unit cell maintaining the perovskite structure of solid solution and the lattice constant of Ta-doped BHT ceramics increases with the increase of Ta content. After doped Ta the grains become closely global or sheet. It is found that both the remanent polarization and the coercive electric field gradually decrease as the Ta content increases from 0.5 mol% to 2 mol%. [ABSTRACT FROM AUTHOR]

Strontium lanthanum niobate (SLN) ceramics were prepared by the conventional mixed-oxide method and the crystalline microstructure, surface morphology and electric properties were investigated. The x-ray diffraction pattern shows that there exist no other phases. The grains turn from club-shaped into sheet and become uniform as lanthanum content increases from 0.03 to 0.12. The dielectric constant decreases with the increasing lanthanum content. As the lanthanum content increases from 0.03 to 0.12, the hysteresis loop becomes gradually slimmer and slimmer, and then both the remanent polarization and the coercive field decrease. [ABSTRACT FROM AUTHOR]

BaSnTiO (short for BTS) ceramics are prepared via the conventional solid state reaction method. The microstructures, diffuse phase transiton, dielectric and ferroelectric properties of BTS ceramics were investigated. These results indicate that Sn ions have entered the unit cell maintaining the perovskite structure of solid solution. The incorporation of SnO can limit grain growth in the BTS ceramics. The Curie temperature of BTS ceramics decreases with the increasing of tin content. Addition of tin can decrease dielectric loss of BTS ceramics at room temperature. The diffuseness of the phase transition of BTS ceramics enhances with the increasing of tin content. The coercive electric field ( E) increases as tin content increases when x is 0.10-0.20. Moreover, the remanent polarization ( P) of BTS ceramics decreases with the increasing of tin content. [ABSTRACT FROM AUTHOR]

Pure and Mn-doped BaTiSnO ceramics are prepared via the conventional solid state reaction method. The microstructures, dielectric properties, and diffuse transition of BaTiSnO ceramics with 0, 0.2, 1 and 2 at.% Mn have been investigated. The results indicate that manganese ions enter the unit cell maintaining the perovskite structure of solid solution. Grain size of BaTiSnO ceramics sharply decreases after doping MnO. However, once MnO content is more than 0.2 at.%, the average grain size of Mn-doped BaTiSnO ceramics increases with the increasing of MnO content. The addition of manganese leads to the increase of the Curie temperature. The diffuseness of the phase transition of Mn-doped BTS ceramics decreases with the increase of Mn content, which may be due to grain size effect. [ABSTRACT FROM AUTHOR]

Pure and Al-doped BaZr0.2Ti0.8O3 (short for BZT) ceramics are prepared via the conventional solid state reaction method. The microstructures, dielectric properties, and diffuse transition of Al-doped BaZr0.2Ti0.8O3 ceramics were investigated. These results indicate that aluminum ions enter the unit cell maintaining the perovskite structure of solid solution. The addition of aluminum leads to the change of the Curie temperature. The dielectric loss of the Al-doped BZT ceramics is higher than that of pure BZT ceramics, and increases as aluminum content increases. The diffuseness of the phase transition of Al-doped BZT ceramics weakens with the increasing of aluminum content. There is no obvious frequency dispersion around the dielectric constant peaks for Al-doped BZT ceramics. The coercive electric field ( EC) increases as Al content increases, and the remanent polarization ( Pr) of Al-doped BZT ceramics is lower than that of pure BZT ceramics. [ABSTRACT FROM AUTHOR]

This paper reviews various sources of literature on the languages of the She minority. Previous scholarship can generally be divided into three aspects: those that study the genetic affiliation of the She language (Sheyu); those that study the relation between the She speech (Shehua) and Chinese dialects, or between Shehua and Zhuang-Dong languages; and those that study languages of the She people as an endangered language. The paper points out the future development of She research, which will aim at safeguarding languages of the She minority. The status of Sheyu and Shehua and their interrelationship will be better clarified when studies proceed with the perspective of basic core vocabulary. Furthermore, studies on languages of the She minority require interdisciplinary methodologies that combine language competition and mathematical modeling to explore factors contributing to the endangerment of She people's languages. [ABSTRACT FROM AUTHOR]

BaZr0.2Ti0.8O3 films were prepared using inorganic zirconate and the crystalline microstructure, surface morphology and ferroelectric properties of BZT films were investigated. It is found that the crystal structure of the films belongs to tetragonal phase and is close to cubic phase. The obvious polarization versus electric voltage (P-V) hysteresis loop and butterfly-shaped ε-V curves were observed in BaZr0.2Ti0.8O3 films. The remanent polarization (2Pr) and the coercive field (2EC) of BaZr0.2Ti0.8O3 films obtained from the hysteresis loop are 0.1669 μC/cm2 and 21.53 kV/cm, respectively. The dielectric constant and tunability of the BaZr0.2Ti0.8O3 films are 113 and 10.2%, respectively. [ABSTRACT FROM AUTHOR]

The surface morphology and dielectric properties of BaZr0.2Ti0.8O3 ceramics sintered at 1350°C for 0.5 h, 4 h and 8 h in air atmosphere were investigated. As the sintering time increased, the average grain size of the BZT ceramics increased. The temperature dependence of the dielectric constant was studied and an enhanced diffuse phase transition behavior is found to be caused by the decreased grain size. [ABSTRACT FROM AUTHOR]

The gastrin precursor peptide, progastrin (PG), is secreted from enteroendocrine cells in the intestine and increased in patients with hypergastrinemia and colorectal cancers. In recent years, we and others have demonstrated an important role of PG peptides in colorectal carcinogenesis, and were surprised to note significant changes in the behaviors of transgenic mice overexpressing PGs. In the present studies, we examined emotional behaviors of transgenic mice overexpressing PG in the intestinal and peripheral circulation. Aggression, locomotor activity and anxiety-like behaviors of the homozygous transgenic (Tg/Tg) mice and the wild-type (WT) littermates were examined by intruder/resident test, open field and elevated plus maze, respectively. A significant increase in the aggression, locomotor activity, and anxiety-like behaviors was detected in the Tg/Tg vs WT mice. As CCK, CCK2 receptors (CCK2R), and 5-HT1A receptors (5-HT1AR) in the CNS play an important role in these behaviors, possible changes in the expression of CCK and CCK2R and the density of CCK2R and 5-HT1AR were determined by either real-time RT-PCR or autoradiography of ligand binding assays. The results suggest that the expressions of CCK and CCK2R were increased in the hypothalamus, and the density of CCK2R were increased in the hypothalamus and amygdala of Tg/Tg vs WT mice. Similarly, the density of 5-HT1AR was increased in the hypothalamus. Our results suggest that an upregulation of the CCK response system and 5-HT1AR in the hypothalamus of Tg/Tg mice may mediate the alterations in the observed behaviors of these mice.Neuropsychopharmacology (2007) 32, 1813–1821; doi:10.1038/sj.npp.1301304; published online 17 January 2007 [ABSTRACT FROM AUTHOR]

Till now, the medicines approved for acute myeloid leukemia with internal tandem duplication mutation of FMS-like tyrosine kinase 3 (FLT3-ITD) display not ideal efficacy. This study aimed to evaluate the effects of 15,16-dihydrotanshinone I on FLT3-ITD acute myeloid leukemia cells. The inhibitory effect of this compound against MV4-11 was determined using CCK-8 assay. Western blotting detecting caspase-3, PARP, and annexin V-APC/7- AAD was carried out. Activation of FLT3, STAT5, and Mcl-1 expression was analyzed by western blotting. The results showed that MV4-11 was sensitive toward dihydrotanshinone I in a dose-dependent manner (p<0.05). MV4-11 apoptosis was induced notably after dihydrotanshinone I treatment. Western blotting revealed suppressed activation of FLT3, STAT5 and decreased Mcl-1 (p<0.05). This study suggests that dihydrotanshinone I inhibits MV4-11 proliferation by apoptosis via antagonizing FLT3-ITD/STAT5/Mcl-1 pathway, which might provide a novel therapy for acute myeloid leukemia. [ABSTRACT FROM AUTHOR]

Till now, the medicines approved for acute myeloid leukemia with internal tandem duplication mutation of FMS-like tyrosine kinase 3 (FLT3-ITD) display not ideal efficacy. This study aimed to evaluate the effects of 15,16-dihydrotanshinone I on FLT3-ITD acute myeloid leukemia cells. The inhibitory effect of this compound against MV4-11 was determined using CCK-8 assay. Western blotting detecting caspase-3, PARP, and annexin V-APC/7-AAD was carried out. Activation of FLT3, STAT5, and Mcl-1 expression was analyzed by western blotting. The results showed that MV4-11 was sensitive toward dihydrotanshinone I in a dose-dependent manner (p<0.05). MV4-11 apoptosis was induced notably after dihydrotanshinone I treatment. Western blotting revealed suppressed activation of FLT3, STAT5 and decreased Mcl-1 (p<0.05). This study suggests that dihydrotanshinone I inhibits MV4-11 proliferation by apoptosis via antagonizing FLT3-ITD/STAT5/Mcl-1 pathway, which might provide a novel therapy for acute myeloid leukemia. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about brucellosis cases in China during the 2005-10 period.

A 2.5-nm-thick platinum film with the shape of a Hall bar was deposited by magnetron sputtering on weak ferromagnetic rhombohedral and tetragonal Bi0.9La0.1FeO3 thin films. An anomalous Hall effect (AHE) was observed and studied as a function of magnetic field (H) and temperature (T). For the two samples, besides the obvious difference in the anomalous Hall resistance, the anomalous Hall resistance increases sharply with decreasing temperature, and even changes sign, thus violating the conventional expression. This observation indicates strong proximity effects and local-field-induced magnetic ordering in Pt on weak ferromagnetic thin films of rhombohedral and tetragonal Bi0.9La0.1FeO3 and their contribution to the spin-related measurements should not be neglected. [ABSTRACT FROM AUTHOR]

Citrus huanglongbing (HLB) is a highly destructive disease currently threatening citrus production worldwide. In China, the disease is exclusively associated with 'Candidatus Liberibacter asiaticus', a nonculturable proteobacterium. HLB was observed in Guangdong of China over a hundred years ago. Researchers and citrus growers have been battling with the disease through vigorous research and have exercised various control practices. Much of the early work was not well known outside China. This review is intended to fill in gaps of historical information by reviewing selected literature records. Along the way, the HLB system within southern China was evaluated. Emphases were on comparison of symptomatology, evolution of etiology, control practices, and impacts of using next-generation sequencing technology for 'Ca. L. asiaticus' research and detection. [ABSTRACT FROM AUTHOR]

Objects in agricultural soils will seriously affect the farming operations of agricultural machinery. At present, it still relies on human experience to judge abnormal Gounrd-penetrting Radar (GPR) signals. It is difficult for traditional image processing technology to form a general positioning method for the randomness and diversity characteristics of GPR signals in soil. Although many scholars had researched a variety of image-processing techniques, most methods lack robustness. In this study, the deep learning algorithm Mask Region-based Convolutional Neural Network (Mask-RCNN) and a geometric model were combined to improve the GPR positioning accuracy. First, a soil stratification experiment was set to classify the physical parameters of the soil and study the attenuation law of electromagnetic waves. Secondly, a SOIL-GPR geometric model was proposed, which can be combined with Mask-RCNN's MASK geometric size to predict object sizes. The results proved the effectiveness and accuracy of the model for position detection and evaluation of objects in soils; then, the improved Mask RCNN method was used to compare the feature extraction accuracy of U-Net and Fully Convolutional Networks (FCN); Finally, the operating speed of agricultural machinery was simulated and designed the A-B survey line experiment. The detection accuracy was evaluated by several indicators, such as the survey line direction, soil depth false alarm rate, Mean Average Precision (mAP), and Intersection over Union (IoU). The results showed that pixel-level segmentation and positioning based on Mask RCNN can improve the accuracy of the position detection of objects in agricultural soil effectively, and the average error of depth prediction is 2.87 cm. The results showed that the detection technology proposed in this study integrates the advantage of soil environmental parameters, geometric models, and artificial intelligence algorithms to provide a high-precision and technical solution for the GPR non-destructive detection of soils. [ABSTRACT FROM AUTHOR]

Xanthomonas citri pv. citri (Xcc), a gram-negative bacterium, is the causal agent of citrus canker, one of the most devastating diseases threatening the citrus industry worldwide. Understanding the diversity and population structure of Xcc is a prerequisite for disease epidemiological monitoring and effective disease management. Recent characterization of the clustered regularly interspaced short palindromic repeats (CRISPR)/cas (CRISPR-associated proteins genes) system with a highly variable repeat number among species provides a new molecular typing method for bacterial genetic analysis. In this study, we performed systematic in silico analyses of 28 Xcc genomes and identified a credible CRISPR/cas in Xcc strains. Further analysis of CRISPR polymorphisms (repeat number and spacer types) in 129 Xcc A strains collected from six provinces in China identified 15 types of CRISPR arrays with 25 spacers. Phylogenetic analysis of Xcc strains based on the CRISPR locus produced a more reliable and accurate typing result compared to the commonly used loci. In addition, seven associated cas genes--cas 1, cas 2, cas 3, cas 4, cas 5, cas 7 (csd 2), and cas 8 (csd 1)--were found located adjacent to the CRISPR array. BLAST results showed > 99% similarity of seven cas genes among Xcc strains. Homology analysis of spacer sequences showed that six spacers had possible phage/prophage origin. The characterization of the CRISPR/cas system among Xcc strains provided an updated strain typing method for Xcc diversity analysis and yielded a panoramic view of CRISPR evolution for further studies of Xcc -phage interactions. [ABSTRACT FROM AUTHOR]

With the gradual deterioration of the ecological environment and the increase in requirements for the quality of modern life, the use of pesticides is bound to develop towards higher pesticide utilization and less environmental pollution, and the low-volume spraying for agricultural aviation operation combined with the Drift Reducing Technologies (DRTs) may be a useful way to achieve this goal. Based on an analysis of the spray drift mechanism and the primary factors influencing aerial spraying, previous research on DRTs in aerial spraying were reviewed and summarized, and it was found that DRTs in aerial spraying can effectively reduce the environmental pollution caused by pesticide drift by reducing the spraying amount of pesticides and improving the control effect of pesticides, included aerial electrostatic spray technology, aerial spray adjuvant, aerial air-assisted spray technology, drift reducing nozzles and aerial variable-rate spray technology. And according to the analysis of the current research status, some suggestions and countermeasures to reduce droplet drift of agricultural aviation spraying were put forward from the aspects of strengthening the research on DRTs for plant protection Unmanned Aerial Vehicle (UAV) and adopting reasonable DRTs methods. It is hoped that provide reference and guidance for the enterprises’ product improvement and users’ practical operation, and play the advantages of precision agricultural aviation spraying fully [ABSTRACT FROM AUTHOR]

Prophages, the lysogenic form of bacterial phages, are important genetic entities of 'Candidatus Liberibacter asiaticus' (CLas), a nonculturable α-proteobacterium associated with citrus Huanglongbing. Two CLas prophages have been described, SCI (NC_0l9549.1, Type 1) and SC2 (NC_019550.1, Type 2), which involve the lytic cycle and the lysogenic cycle, respectively. To explore the prophage repertoire, 523 CLas DNA samples extracted from leaf petioles of CLas-infected citrus were collected from southern China and surveyed for Type 1 and Type 2 prophages by specific PCR. Eighteen samples were found lacking both prophages. One sample, JXGC, sequenced using Ulumina HiSeq, generated > 1 (X) million short sequence reads (150 bp per read). Read mapping to known prophage sequences showed a sequence coverage of 46% to SCI and 50% to SC2. BLAST search using SC 1 and SC2 as queries identified three contigs from the JXGC de novo assembly that form a circular P-JXGC-3 (31,449 bp), designated as a new Type 3 prophage. Chromosomal integration of PJXGC-3 was detected to occur within a helicase gene, resulting in a duplication of this gene. P-JXGC-3 had 36 open reading frames (ORFs), 10 of which were not found in Type 1 or Type 2 prophages, including four genes that encoded a restriction-modification (R-M) system (hsdR, hsdS, hsdMl, and hsdM2). Typed by prophage-specific PCR. the CLas strains in southern China contained all combinations of the three prophage types with the exception of a Type 2-Type 3 combination, suggesting active ongoing prophage-phage interactions. Based on gene annotation, PJXGC-3 is not capable of reproduction via the lytic cycle. The R-M system was speculated to play a role against Type I prophage-phage invasion. [ABSTRACT FROM AUTHOR]

To investigate the effect of cAMP response element-binding protein H (CREBH) on metabolic associated fatty liver disease by regulating sirtuin 3 (SIRT3). Two mouse models of fatty liver induced by a methionine-choline deficient (MCD) diet and a high-fat (HF) diet and an in vitro model of palmitic acid (PA) induced lipid-overloaded hepatocytes were constructed to detect the expression of CREBH, SIRT3, total acetylation, and downstream protein interactions and lipid metabolism phenotype, which were further validated in CREBH−/− mice and lentivirus-overexpressing CREBH hepatocytes. In fatty liver and lipid overload models, the expressions of CREBH and SIRT3 were down-regulated and their expression was positively correlated, accompanied by an increase in the level of total protein acetylation. Overexpression of CREBH alleviated excess lipid accumulation, impaired viability, and the ability to metabolize energy through the fatty acid oxidation pathway in hepatocytes in vitro. Furthermore, overexpression of CREBH restored the interaction of the deacetylase SIRT3 with the molecules carnitine palmitoyl-transferase 2 (CPT2) and long-chain acyl CoA dehydrogenase (ACADL) involved in the fatty acid oxidation pathway and their deacetylation status. However, CREBH−/− aggravated the damage of lipid metabolism in the liver tissue of mice. CREBH increased the enzymatic activity of downstream factors by positively regulating the expression of SIRT3, which promoted the oxidative decomposition of fatty acids in hepatocytes and played an important role in fatty acid oxidation in MAFLD. Abbreviations: CREBH, cAMP response element-binding protein H; SIRT3, sirtuin 3; CPT2, carnitine palmitoyl-transferase 2; ACADL, long-chain acyl CoA dehydrogenase; MCD, methionine-choline deficient; HF, high-fat; PA, palmitic acid; MAFLD, metabolic associated fatty liver disease; CD, chow diet; MOI, optimal multiplicity of infection; qRT-PCR, quantitative real-time polymerase chain reaction; K-Ac, lysine acetylation; PPARα, peroxisome proliferator-activated receptor alpha; OE, overexpression; MCAD, medium-chain acyl-CoA dehydrogenase; ACADVL, very-long-chain acyl-CoA dehydrogenase; ACAT1, acetyl-CoA acetyltransferase 1; ECHS1, enoyl-CoA hydratase-1; HMGCS2, 3-hydroxy-3-methylglutaryl-CoA synthetase 2; PTMs, post-translational modifications. [Display omitted] • The expression of CREBH is positively correlated with SIRT3. • CREBH alleviates hepatocyte lipid accumulation by upregulating SIRT3. • CREBH promotes deacetylation and enzyme activation of CPT2 and ACADL involved in fatty acid oxidation by upregulating SIRT3. • CREBH deficiency aggravates lipid metabolism disorders in MAFLD mice. [ABSTRACT FROM AUTHOR]

Miniature inverted-repeat transposable elements (MITEs) are nonautonomous transposons (devoid of the transposase gene tps) that affect gene functions through insertion/deletion events. No transposon has yet been reported to occur in "Candidatus Liberibacter asiaticus," an alphaproteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease). In this study, two MITEs, MCLas-A and MCLas-B, in "Ca. Liberibacter asiaticus" were detected, and the genome was characterized using 326 isolates collected in China and Florida. MCLas-A had three variants, ranging from 237 to 325 bp, and was inserted into a TTTAGG site of a prophage region. MCLas-A had a pair of 54-bp terminal inverted repeats (TIRs), which contained three tandem repeats of TGGTAACCAC. Both "filled" (with MITE) and "empty" (without MITE) states were detected, suggesting the MITE mobility. The empty sites of all bacterial isolates had TIR tandem repeat remnants (TRR). Frequencies of TRR types varied according to geographical origins. MCLas-B had four variants, ranging from 238 to 250 bp, and was inserted into a TA site of another "Ca. Liberibacter" prophage. The MITE, MCLas-B, had a pair of 23-bp TIRs containing no tandem repeats. No evidence of MCLas-B mobility was found. An identical open reading frame was found upstream of MCLas-A (229 bp) and MCLas-B (232 bp) and was predicted to be a putative tps, suggesting an in cis tps-MITE configuration. MCLas-A and MCLas-B were predominantly copresent in Florida isolates, whereas MCLas-A alone or MCLas-B alone was found in Chinese isolates. [ABSTRACT FROM AUTHOR]

Prophages are important genetic elements of bacterial genomes and are involved in lateral gene transfer, pathogenicity, environmental adaptations, and interstrain genetic variability. In this study, the sequence of a prophage terminase gene of 'Candidatus Liberibacter asiaticus', a bacterium associated with citrus Huanglongbing (HLB), was selected as a molecular marker to assess the genetic variation in two 'Ca. L. asiaticus' populations from geographically distinct provinces (Guangdong and Yunnan) in China. The frequency of the prophage terminase gene was 15.8% (19/120) in Guangdong (altitude <500 m) and 97.4% (38/39) in Yunnan (altitude >2,000 m). The difference was highly significant (P < 0.0001) based on χ2 analysis. However, the partial prophage terminase gene sequences obtained from 10 Guangdong strains and 6 Yunnan strains were identical or highly similar, suggesting that at least some bacterial strains in the two locations shared a common recent origin. This is the first report on population variation of 'Ca. L. asiaticus' in China, where HLB was first described. The population variation of 'Ca. L. asiaticus' in the two geographical regions and the related HLB epidemiology were discussed. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the study was to validate a semi-quantitative food frequency questionnaire1 (SQFFQ) against 3 day weighted diet records (WDRs) for middle-aged inhabitants in the Chaoshan area, China., Subjects: 100 middle-age healthy residents., Methods: Validity was examined via descriptive statistics and Pearson's correlations., Results: Pearson's correlation coefficients (CCs) with energy-adjustment quantified by the SQFFQ and 3 day WDRs (minimum-median-maximum) ranged from 0.31(Vegetables)-0.35-0.53 (Cereals) for the selected foods, and 0.12 (retinol)-0.41-0.58 (phosphorous) for the selected nutrients. Favorably high agreement for intakes of foods/nutrients was achieved along with low disagreement., Conclusion: A moderate level of relative validity was observed; this food frequency questionnaire is reliable and valid for dietary assessment with middle-aged inhabitants in the Chaoshan area, China.