Search

Soil microbes’ response to sudden environmental changes is very complicated and has been lively debated. There are a handful of questions yet to answer: are there any succession rules for different...

This study isolated and characterized a novel polysaccharide (PNPS-0.3) from the residue of Panax notoginseng by gradient elution. PNPS-0.3 mainly consisted of a backbone of →4)- α-D-GalAp-(1 → 4-β-L-Rhap-1 → 4)-β-D-Galp-(1 → residues, with an α-L-Araf-1 → 5)-α-L-Araf-(1 → branch connecting to the backbone at O-3 of →4-β-L-Rhap-1 → and a molecular weight of 76,655 Da. Furthermore, the adjuvant potential of PNPS-0.3 with bone marrow dendritic cells (BMDCs) was investigated. The results suggested that PNPS-0.3 could induce maturation of BMDCs by reshaping the morphology, upregulating the CD40, CD80, CD86 and MHC II membrane phenotypic markers, and by promoting the secretion of TNF-α and IL-12 proinflammatory cytokines. Moreover, PNPS-0.3 can trigger the DC-induced T-cell immune response, as indicated by the higher expressions of CD4, CD8, CD69, and MHC II in T cells with increased secretion of INF-β. Furthermore, PNPS-0.3 can bind to the pattern recognition receptors (PRR) of Toll-like receptor 4 (TLR 4), Toll-like receptor 2 (TLR 2), and mannose receptor (MR) on BMDCs. PNPS-0.3 also upregulated the expressions of Myd88, IKKβ, PP65, T-P65, and NF-κB, suggesting that the TLR4/TLR2-NF-κB signaling pathway was involved in the immunomodulatory mechanism. In conclusion, the immunoadjuvant potential of novel PNPS-0.3 was characterized, which is beneficial for the future utilization and development of P. notoginseng.

Salicylic acid (SA) and nitric oxide (NO) are key signal molecules involved in the reduction of Al accumulation in many plants. The purpose of this study was to investigate whether they could reduce the root content of Al and/or its binding to the root cell wall (CW) fractions in Panax notoginseng, and to investigate the corresponding regulatory mechanisms. Effects of Al treatments on the endogenous SA and NO contents of P. notoginseng were detected. Exogenous SA and paclobutrazol (PAC, a SA synthesis inhibitor) treatments were conducted to test the effects on endogenous NO content; exogenous sodium nitroprusside (SNP, a NO doner) and 2-phenyl-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxyde (cPTIO, a NO synthesis inhibitor) treatments were conducted to test the effects on endogenous SA content. Pectin methyltransferase (PMT) and pectin methylesterase (PME) activity and the gene expression, pectin methylesterification degree (PMD), pectin content, and the accumulation of Al in roots were also studied under the treatments described above. Al stress induced a significant increase of the activity and expression of phenylalanine ammonia-lyase (PAL), and promoted the significant increase of endogenous SA content of P. notoginseng roots. The Al promoted accumulation of endogenous NO could be enhanced by exogenous SA treatment, but was reduced by PAC. Accumulation of endogenous NO that promoted by Al could be enhanced by exogenous SA treatment, but was reduced by PAC treatment. However, SNP or cPTIO treatments had no significant effect on the Al-induced endogenous SA content of P. notoginseng. This showed that NO acted downstream of SA signaling of P. notoginseng under Al stress. Al stress can increase the activity and genes expression of PME in the roots of P. notoginseng, reduce PMD, increase CW pectin content, and thus, the binding capacity of CW pectin to Al was enhanced in P. notoginseng roots. Exogenous SA or SNP both reduced the Al-binding capacity of root CW pectin by decreasing the pectin content, and increased the PMD by inhibiting the genes expression and activity of PME. The effects of PAC or cPTIO on the above-mentioned indicators under Al stress were opposite to that of exogenous SA or SNP treatments. The Al stress induced accumulation of pectin and the reduction of PMD in the root CW of P. notoginseng could be reversed by the treatments of exogenous SA or SNP, then the Al contents in root CW pectin were reduced. Al stress activated the endogenous SA and NO signaling pathways in P. notoginseng, and NO acted downstream of SA. It showed that the Al-activated NO-SA signaling pathway contributed in the reduction of Al binding to the root under Al stress.

Panax notoginseng is normally cultivated in acidic red soil with high soluble Al, however, the distribution pattern of Al in P. notoginseng is unknown. The aim of this study is to investigate the Al distribution in different organs of P. notoginseng grown in different acid soil, in order to get a deeper insight into the Al tolerance mechanism in this species. P. notoginseng was sampled from different sites and subjected to Al determination. Al tolerance and accumulation were investigated by exposing the seedlings to different Al concentrations in hydroponic solution. The expression of pectin methylesterase genes was determined by quantitative RT-PCR. The soil pH ranged from 4.68 to 6.13. The total Al concentration in soil was 76.7–168.5 g·kg−1 and active Al was 1.34–5.01 g·kg−1. Al concentration differed with organs of P. notoginseng, following the order: rootlet > rhizome > main root > leaf and stem. Furthermore, Al concentration in the cell wall, organelle and cytoplasmic supernatant of P. notoginseng was approximately 15:2:1 and most Al in the cell wall was bound to pectin component. Al treatment significantly increased the content of pectin and enhanced the expression of PME3, PME7, and PME40 of P. notoginseng root. P. notoginseng was able to grow under high active Al condition and accumulated high Al in its underground parts. The pectin component in the cell wall was the major binding site of Al of P. notoginseng root.

The objective of this study was to assess the genetic diversity of porcine reproductive and respiratory syndrome virus circulating in Fujian province (southeastern China). Based on 53 ORF5 nucleotide sequences collected from nine sites, both highly pathogenic (sublineage 8.7) and lineage 1 strains were circulating in Fujian in 2009-2014 along with lineages 3 and 5.1. Notably, the lineage 1 strains were closely related to the NADC30 strain circulating in North America and were the predominant strains in 2014. In addition, we found that nonstructural protein 2 (NSP2) was the most variable nonstructural protein in Fujian isolates, with a 36-amino-acid (aa) insertion and seven different deletions detected in the 53 sequences examined. Similarly, analysis of GP5 amino acid sequences showed that the isolates were highly variable in primary neutralizing epitopes. Interesting, FJ3.2 and FJ7-2 strains have the mutation N44K, but they exhibited high replication and high titers in MARC-145 and PAM cells. The complete genome sequences determined for 12 type 2 isolates were 82.1-99.3% identical and were 15,016-15,407 nucleotides (nt), in length excluding the poly(A) tail. The strains also shared 88.2-99.4% identity with strain VR2332 (the prototype North American strain), 83.4-99.2% identity with strain JXA1 (the prototype high-pathogenicity Chinese strain), 88.2-97.1% identity with strain CH-1a (the prototype classical Chinese strain), and 82.9-97.1% identity with strain NADC30 (the prototype NADC30-like strain). Strikingly, phylogenetic and molecular evolutionary analyses indicated that strain FJW05 is a spontaneous recombinant between a circulating lineage 1 virus and the vaccine strain JXA1-R, which is derived from the highly pathogenic strain JXA-1. Collectively, the data highlight the epidemiology of porcine reproductive and respiratory syndrome in Fujian and may aid in selecting a suitable vaccine for use on pig farms.

From 2014 to 2015, four novel highly pathogenic PRRS virus (HP-PRRSV) strains named 14LY01-FJ, 14LY02-FJ 15LY01-FJ, and 15LY02-FJ were isolated from high morbidity (100%) and mortality (40%-80%) in piglets and sows in Fujian Province. To further our knowledge about these novel virus strains, we characterized their complete genomes and determined their pathogenicity in piglets. Full-length genome sequencing analysis showed that these four isolates were closely related to type 2 (North American type, NA-type) isolates, with 88.1%-96.3% nucleotide similarity, but only 60.6%-60.8% homology to the Lelystad virus (LV) (European type, EU-type). The full length of the four isolates was determined to be 15017 or 15018 nucleotides (nt), excluding the poly(A) tail. Furthermore, the four isolates had three discontinuous deletions (aa 322-432, aa 483, and aa 504-522) within hypervariable region II (HV-II) of Nsp2, as compared to the reference strain VR-2332. This deletion pattern in the four isolates is consistent with strain MN184 and strain NADC30 isolated from America. Phylogenetic and molecular evolutionary analyses indicated that these virulent strains originated from a natural recombination event between the JXA1-like HP-PRRSV (JXA-1 is one of the earliest Chinese HP-PRRSV strains; sublineage 8.7) and the NADC30-like (lineage 1) PRRSV. Animal experiments demonstrated that these four strains caused significant weight loss and severe histopathological lung lesions as compared to the negative control group. High mortality rate (40% or 80%) was found in piglets infected with any one of the four strains, similar to that found with other Chinese HP-PRRSV strains. This study showed that the novel variant PRRSV was HP-PRRSV, and it is therefore critical to monitor PRRSV evolution in China and develop a method for controlling PRRS.

Background The large family of pentatricopeptide repeat (PPR) proteins is widely distributed among land plants. Such proteins play vital roles in intron splicing, RNA editing, RNA processing, RNA stability and RNA translation. However, only a small number of PPR genes have been identified in rice. Results In this study, we raised a mutant from tissue-culture-derived plants of Oryza sativa subsp. japonica ‘Zhonghua 11’, which exhibited a lethal chlorosis phenotype from germination to the third-leaf stage. The mutant was designated seedling-lethal chlorosis 1 (slc1). The slc1 mutant leaves showed extremely low contents of photosynthetic pigments and abnormal chloroplast development, and were severely defective in photosynthesis. Map-based cloning of OsSLC1 revealed that a single base (G) deletion was detected in the first exon of Os06g0710800 in the slc1 mutant, which caused a premature stop codon. Knockout and complementation experiments further confirmed that OsSLC1 is responsible for the seedling-lethal chlorosis phenotype in the slc1 mutant. OsSLC1 was preferentially expressed in green leaves, and encoded a chloroplast-localized PPR protein harboring 12 PPR motifs. Loss-of-function of OsSLC1 affected the intron splicing of multiple group II introns, and especially precluded the intron splicing of rps16, and resulted in significant increase in the transcript levels of 3 chloroplast ribosomal RNAs and 16 chloroplast development-related and photosynthesis-related genes, and in significant reduction in the transcript levels of 1 chloroplast ribosomal RNAs and 2 chloroplast development-related and photosynthesis-related genes. Conclusion We characterized a novel chloroplast-localized PPR protein, OsSLC1, which plays a vital role in the intron splicing of multiple group II introns, especially the rps16 intron, and is essential for early chloroplast development and seedling survival in rice.

The present study aims to optimize the ethanol-reflux extraction conditions for extracting saponins from steamed Panax notoginseng (SPN). Four variables including the extraction time (0.5–2.5 h), ethanol concentration (50–90%), water to solid ratio (W/S, 8–16), and times of extraction (1–5) were investigated by using the Box-Behnken design response surface methodology (BBD-RSM). For each response, a second-order polynomial model with high R2 values (>0.9690) was developed using multiple linear regression analysis and the optimum conditions to maximize the yield (31.96%), content (70.49 mg/g), and antioxidant activity (EC50 value of 0.0421 mg/mL) for saponins extracted from SPN were obtained with a extraction time of 1.51 h, ethanol concentration of 60%, extraction done 3 times, and a W/S of 10. The experimental values were in good consistency with the predicted ones. In addition, the extracted SPN saponins could significantly increase the levels of blood routine parameters compared with the model group (p < 0.01) and there was no significant difference in the hematopoiesis effect between the SPN group and the SPN saponins group, of which the dose was 15 times lower than the former one. It is suggested that the SPN saponins extracted by the optimized method had similar functions of “blood tonifying” at a much lower dose.

Haemophilus parasuiscan cause Glässer’s disease characterized by fibrinous polyserositis, polyarthritis, and meningitis. The current prevention of Glässer’s disease is mainly based on the inactive vaccines; however, the protective efficacy usually fails in heterogeneous or homologous challenges. Here, the predominant lineage ofH. parasuis(LY02 strain) in Fujian province, China, characterized as serovar 5, was used to evaluate the protective immunity against acuteH. parasuisinfection in piglets after inactivation. Following challenging withH. parasuis,only mild lesions in the pigs immunized with the killed vaccine were observed, whereas the typical symptoms of Glässer’s disease presented in the nonimmunized piglets. A strong IgG immune response was induced by the inactive vaccine. CD4+and CD8+T lymphocyte levels were increased, indicating the potent cellular immune responses were elicited. The significantly high levels of IL-2, IL-4, TGF-β, and IFN-γin sera from pigs immunized with this killed vaccine suggested that the mixed Th1 and Th2 immune responses were induced, associated with the high protection againstH. parasuisinfection compared to the nonimmunized animals. This study indicated that the inactivated LY02 strain ofH. parasuiscould serve as a potential vaccine candidate to prevent the prevalence ofH. parasuisin Fujian province, China.

To more fully understand the extent of genetic diversity of PRRSV in China, we analyzed the Nsp2 and ORF5 gene sequences of 35 representative PRRSV isolates from 2008 to 2012. Sequence analysis revealed that the Nsp2 and ORF5 genes have undergone genetic variation. Furthermore, the isolate FJLYDX04 contains five insertions at positions 599 to 603 and is the first isolate from China reported to have an insertion in Nsp2. Our results suggest that the highly pathogenic PRRSV has become the dominant strain in China and that Chinese PRRSV has undergone rapid evolution and can circumvent immune responses induced by currently used vaccines.

The production and quality of Tie-Guan-Yin tea (Camellia sinensis) decrease with time after continuous picking over multiple years. However, it is unclear how the soils of consecutively cultured tea plantations affect the growth of tree seedlings. In this study, soil samples were collected from 4-, 9-, and 30-age Tie-Guan-Yin plantations within the original production area, Longjuan town, Anxi County, China. The toxicity of soil samples were tested by laboratory bioassay. Then, new tea seedlings were transplanted in situ into the land of three age tea plantations. One year after transplantation, the growth indexes, physiological parameters (protective enzymes and primary metabolites), photosynthesis parameters, and main tea quality indicators were measured. The results showed that the 4-, 9-, and 30-age soils inhibited lettuce root growth by 10.32, 24.19, and 48.04 %, respectively. The consecutively cultured soil negatively impacted on the growth, physiology, photosynthesis, and overall quality of transplanted tea seedlings. For example, seedlings grown in the 30-age soil had 20 % lower growth rates, 17 % less soluble sugar, 28 % less soluble protein, 37 % less polyphenol, 34 % less theanine, 25 % less amino acid, 37 % less caffeine, and 40 % less of eight catechols than tea seedlings grown in new soil with no history of tea production. These results indicated that the soils of consecutively cultured tea plantations resulted in significant autotoxicity which negatively affected tea seedling growth, metabolism, tea yield, and tea quality. Greater understanding of the causes and mechanisms of autotoxicity is critical to the reclamation of longstanding tea plantation and improvement of the yield and quality of the tea they produce.

Effect of different water conditions on the physiological indexes (e.g.seed water content, vigor, antioxidase activities)of Panax notoginseng seeds were studied under process of after-ripening and germination.The results showed show that compared with 2.5% treatment, under the treatment of 5%, P.notoginseng seeds possessed stable seed water content, the seed vigor was exceed by 51%,variation of antioxidant enzyme (SOD, POD, CAT) activity and malondialdehyde (MDA) content were small, crude fat and total sugar content decreased significantly.With the increase of PEG 6000 concentration, the germination characteristic indexes obviously decreased, antioxidase activities increased firstly and decreased afterwards, content of MDA, soluble protein and total sugar increased obviously.There were significant positive correlation between germination characteristic indexes and osmotic substance content(r0.900, P0.01), and significant negative correlation with MDA (r0.900, P0.01).In conclusion, because the characteristic of dehydration intolerance of P.notoginseng seeds, 5% water content of sand burying stratification treatment was the best for after-ripening, 15% concentration of PEG 6000 treatment was the highest tolerance limit of germination process.

The objective of the present investigation was to estimate the seroprevalence T. gondii infection in breeding sows in Western Fujian Province, the People's Republic of China. Sera collected from breeding sows during 2006-2007 from 6 different regions in Western Fujian Province were assayed for antibodies to T. gondii by an indirect hemagglutination antibody (IHA) test. Antibodies to T. gondii were detected in 87 (14.38%) of 605 breeding sows. Differences in seroprevalence were observed between sampling regions, ranging from 10.14% to 37.50%. The present investigation demonstrated that the prevalence of T. gondii infection in breeding sows in Fujian Province was high. Integrated control strategies and measures should be implemented to prevent and control T. gondii infection in breeding sows, which in turn will have significant implications for the control of human infection with T. gondii in this province.

A multiplex polymerase chain reaction (PCR) was designed for the simultaneous detection of three viruses involved in reproductive and respiratory failure in pigs: porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV) and porcine circovirus type 2 (PCV-2). Each target produced a specific amplicon with a size of 718 bp (PRRSV), 288 bp (CSFV), or 466 bp (PCV-2). The sensitivity of the multiplex PCR using purified plasmid constructs containing the specific viral target fragments was 2.0 × 10(4), 2.5 × 10(3), and 6.0 × 10(2) copies for PRRSV, CSFV, and PCV-2, respectively. Non-specific reactions were not observed when other viruses, bacteria, and PK-15/Marc-145 cells were used to assess the multiplex PCR. Among 82 clinical samples from Fujian province, co-infection by PRRSV and CSFV was 12.19%, co-infection by PRRSV and PCV-2 was 21.95%, CSFV and PCV-2 was 13.41%, and co-infection by the three viruses was 3.66%. In conclusion, the multiplex PCR should be useful for routine molecular diagnosis and epidemiology. The multiplex PCR was effective in detecting various combinations of one or more of these viruses in pig specimens.

To better understand the pathogenesis of duck virus enteritis (DVE), the levels of viral DNA in various tissues of ducklings during acute stage of virulent duck enteritis virus (DEV) infection were investigated by using quantitative real-time polymerase chain reaction. The results show that the viral levels of DEV in systemic organs have a close correlation with the progression of disease. The rapid dissemination and active replication of virulent DEV in multiple systemic organs at the early phase of acute infection accelerate the progression of disease. The levels of viral DNA increase sharply soon after developed clinical signs of disease, and the extent of increase and the magnitude of DEV DNA load in various tissues of ducklings after the exhibition of clinical signs may be a critical determinant of the outcome of DEV infection. The relatively high levels of DEV in bursa and small intestine tissues of dead ducklings most likely reflect the abundance of target epithelial and lymphoid cells in these tissues, which therefore play a key role in the pathogenesis of acute DVE and manifest as severe tissue lesions on the bursa and small intestine.

Duck virus enteritis is an acute and contagious herpesvirus infection of duck, geese and swans with high morbidity and mortality. The kinetics of viral DNA loads and immunohistochemical localization of virulent duck enteritis virus, as well as histopathological examination in various tissues of ducks following oral infection, were investigated. The time course for the appearance of viral antigen and tissue lesions in various tissues was coincident with the levels of duck enteritis virus at the various sites, suggesting that the levels of duck enteritis virus in systemic organs have a close correlation with the progression of disease. The abundance of target epithelial and lymphoid cells may contribute to the high levels of virus infection and replication in lymphoid and intestinal tissues.