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During the drilling process, high-temperature environments can cause the performance of traditional drilling fluids to decline, affecting drilling efficiency and environmental protection. To address this issue, this study added polymetallic hydroxide to anti-temperature and environmentally protective drilling fluid treatment agents, verifying its performance through linear expansion experiments, anti-expansion experiments, mud ball experiments, and thermogravimetric analysis.The experimental results indicate that at 20 minutes, the expansion rate of bentonite is 44.2% in water and 22.3% in KCl, and at 120 minutes, the expansion rate is 70.4% in water and 50.4% in KCl. When mixing different polymetallic hydroxides with bentonite clay, M1-Fe exhibited the lowest swelling among Fe-doped polymetallic hydroxide samples, with rates of 13.3% at 20 minutes and 22.7% at 120 minutes. Among Cu-doped samples, M2-Cu showed the lowest expansion, at 15.9% at 20 minutes and 25.3% at 120 minutes. For Zn-doped samples, M3-Zn had the lowest expansion rates, at 16.5% at 20 minutes and 27.3% at 120 minutes.The results demonstrate that Fe-doped polymetallic hydroxide samples exhibit excellent swelling inhibition and thermal stability at high temperatures. These samples significantly improve the high-temperature stability and environmental performance of drilling fluids, showing great potential for widespread use in high-temperature drilling. [ABSTRACT FROM AUTHOR]

Surfeit locus protein 4 (SURF4) functions as a cargo receptor that is capable of transporting newly formed proteins from the lumen of the endoplasmic reticulum into vesicles and Golgi bodies. However, the role of SURF4 in the central nervous system remains unclear. The aim of this study is to investigate the role of SURF4 and its underlying mechanisms in cerebral ischemia/reperfusion (I/R) injury in rats, and whether it can be used effectively for novel therapeutic intervention. We also examined whether transcranial direct-current stimulation (tDCS) can exert a neuroprotective effect via SURF4-dependent signalling. Following cerebral I/R injury in rats, a significant increase was observed in the expression of SURF4. In both I/R injury and oxygen–glucose deprivation (OGD) insult, suppressing the expression of SURF4 demonstrated a neuroprotective effect, while overexpression of SURF4 resulted in increased neuronal death. We further showed that the levels of nerve growth factor precursor (proNGF), p75 neurotrophin receptor (p75NTR), sortilin, and PTEN were increased following cerebral I/R injury, and that SURF4 acted through the PTEN/proNGF signal pathway to regulate neuronal viability. We demonstrated that tDCS treatment reduced SURF4 expression and decreased the infarct volume after cerebral I/R injury. Together, this study indicates that SURF4 plays a critical role in ischemic neuronal injury and may serve as a molecular target for the development of therapeutic strategies in acute ischemic stroke. [ABSTRACT FROM AUTHOR]

Peach is one of the most widely grown fruit crops in China, nectarine [Prunus persica (L.) Batsch var. nucipersica (Suckow) C.K. Schneid.] is an important commercial variety of peach. MicroRNAs (miRNAs) play important functions in post-transcriptional gene regulation in plants. In this study, miRNAs and their target genes were identified and predicted by sequencing four small RNA libraries prepared from nectarine leaf and fruit tissues infected with different virus/viroid combinations using next-generation sequencing technology (NGS). A total of 116 known peach miRNAs were identified, and 303 putative novel miRNAs were predicted. Some of these miRNAs were found to be highly conserved. Most of the novel miRNAs were 24-nt in length and many of these miRNAs came from MIR5271 and MIR7717 families. All differently expressed miRNAs had 2785 putative target genes. Comparative profiling revealed that 45 miRNAs exhibited significant differential expression between leaf and fruit tissue. Moreover, expression levels of these miRNAs were significantly affected in the two tissues despite the fact that the trees were infected by different virus/viroid combinations. We also found that there were more differentially expressed miRNAs in leaves tissue than in fruits, and a few miRNAs were identified that play important roles in the response to virus/viroid infection. Our results show that the expression of some miRNAs appears to be tissue-specific, and virus/viroid infection had a greater effect on the miRNA expression profiles in leaves than in fruits of nectarine. We hypothesize that virus/viroid infection induces the production of many novel miRNAs and also affects their lengths. [ABSTRACT FROM AUTHOR]

In the present study, the genome sequence of a potential novel virus, tentatively named "rose virus C" (RVC), was mined from publically available transcriptomic data from a Rosa chinensis plant. The complete genome sequence of RVC consists of 8,386 nt, excluding a 3′ poly(A) tail, and contains five ORFs. Phylogenetic analysis showed that RVC clustered with members of the genus Carlavirus, family Betaflexiviridae. The replicase gene had 48.8-52.1% nt sequence identity to those of other carlaviruses, while the CP gene had 40.4-45.9% nt sequence identity, which is far below the species demarcation cutoff of 72%. The incidence of RVC in rose plants was low (5.4%). Overall, our data suggest that RVC is a novel atypical virus of the genus Carlavirus. [ABSTRACT FROM AUTHOR]

Cestrum species are being used as hedge and ornamental plants in Turkey. In this study, a Cestrum elegans plant showing chlorotic spots, rings and reddening was subjected to high throughput sequencing of small RNAs, in order to clarify its etiology. Results suggested the presence of tomato chlorosis virus (ToCV), which was further confirmed by RT-PCR using two specific primers amplifying RNA-dependent RNA polymerase (RdRp) and coat protein (CP) of the virus. When 25 Cestrum samples were tested using CP primers, one symptomatic C. elegans and four symptomless C. nocturnum were infected by ToCV. The obtained sequences shared 83–99.9% nucleotide identity with ToCV isolates available in the GenBank. Phylogenetic relationship among Turkish tomato isolates of ToCV and those available in the GenBank showed that two Cestrum spp. isolates of ToCV were closely related to Turkish tomato isolates, while the other three clustered with isolates from different countries. [ABSTRACT FROM AUTHOR]

China rose (Rosa chinensis Jacq.) is an important ornamental plant grown widely in China. In May 2019, we sampled and analyzed a China rose plant by high-throughput sequencing using small RNAs. A luteovirus, rose spring dwarf-associated virus (RSDaV), was detected in this plant, and its complete nucleotide sequence of 5816 nucleotides was determined. The China rose isolate of RSDaV contains five major open reading frames (ORFs) and three putative small ORFs, typical of members of the genus Luteovirus. It shares 94.4% nt sequence identity with the Californian (USA) isolate of the virus. Genomic analysis revealed a deletion of a single U at nt position 5295, which introduced a frameshift mutation, and an insertion of nine nucleotides (AUAAAUGAU) at position 5706-5714, which did not change the reading frame. The aa sequence in that portion of the protein was 90.5% identical to that of the Californian isolate. This is the first report on the occurrence of RSDaV infecting rose plants in China. [ABSTRACT FROM AUTHOR]

This article reports the first occurrence of mume-associated luteovirus (MaLV) in apricot trees in China. The virus was identified in a sample from diseased trees in the Xinjiang Uygur Autonomous Region using RNA-sequencing. The sequencing revealed three contigs that were annotated as MaLV, with a 97% nucleotide sequence identity to a Japanese mei isolate. RT-PCR testing confirmed the presence of MaLV in some of the samples. Further research is needed to identify the causal agent of the disease and determine the impact of the virus on different stone fruit species in China. The study was supported by the National Key R & D Program of China and the earmarked fund for China Agriculture Research System. [Extracted from the article]

Prunus necrotic ringspot virus (PNRSV) is a viral pathogen with worldwide distribution, infecting many commercial fruit trees and ornamental plants. So far, the correlation between PNRSV infection and China rose mosaic disease has not been studied. Rose mosaic disease is characterized by severe symptoms, including mosaic, line pattern, and ringspot. Six viruses that were potentially associated with mosaic disease, including PNRSV, were tested in China roses. Only PNRSV was detected in China roses showing mosaic disease, and asymptomatic samples tested negative for this virus. This result was confirmed by small RNA sequencing, but rose leaf rosette-associated virus and rose spring dwarf-associated virus were also identified in both samples with mosaic disease and asymptomatic samples. This implied that PNRSV might be associated with China rose mosaic disease. Full genome sequences of two PNRSV isolates were determined, and the RNA1, 2 and 3 segments were found to be 3,332, 2,594 and 1,951 nucleotides (nt) in length, respectively. The three RNA segments shared 88.7–89.1% nt sequence identity in the 3′UTR, while RNA2 and RNA3 shared 98.2–99.4% identity. The higher variability in RNA1 suggests that it might have been under greater selection pressure. Phylogenetic analysis showed that the two PNRSV isolates clustered in group PV-32. Full-length infectious cDNA clones of PNRSV from China rose were constructed and used to agroinfiltrate cucumber seedlings. The inoculated cucumber leaves showed yellowing, chlorotic spots, necrosis, dwarfing, and decline at 23 to 39 days post-inoculation, demonstrating the virulence of the PNRSV isolate from China rose. These data lay a foundation for determining the molecular mechanism of rose mosaic disease caused by PNRSV. [ABSTRACT FROM AUTHOR]

"Gandarusa" with the attachment of parasitic plants were planted besides three one-month-old "Gandarusa". The perianths had six tepals, the outer three tepals were ovate, while the inner three tepals were elliptic glabrous. "Gandarusa" ( I Justicia gendarussa i , family Acanthaceae) is an evergreen shrub. [Extracted from the article]

The complete nucleotide sequence of fig fleck-associated virus from Xinjiang Uygur Autonomous Region of China (FFkaV-CN) was determined. The 6,723-nucleotide-long viral genome, excluding a terminal poly(A) tail, contains three open reading frames (ORFs). Pairwise comparisons showed that FFkaV-CN shares 83% and 92% sequence identity with FFkaV-Italy based on the complete genomic sequence and CP aa sequence, respectively, slightly higher than the species demarcation criterion for the genus Maculavirus. Phylogenetic analysis showed that FFkaV-CN and FFkaV-Italy clustered into one group. These results indicate that FFkaV-CN is a novel strain of FFkaV with a genome organization somewhat different from what was reported for FFkaV-Italy. [ABSTRACT FROM AUTHOR]

The causal agent of apple mosaic disease has been previously thought to be solely caused by apple mosaic virus (ApMV). In this study, we report that a novel ilarvirus is also associated with apple mosaic disease. Next-generation sequencing analysis of an apple tree showing mosaic symptoms revealed that the tree was infected with three apple latent viruses (apple stem pitting virus, apple stem grooving virus, and apple chlorotic leaf spot virus) and a novel ilarvirus (given the name apple necrotic mosaic virus (ApNMV)) that is closely related to Prunus necrotic ringspot virus (PNRSV) and ApMV. The genome of ApNMV consists of RNA1 (3378 nt), RNA2 (2767 nt), and RNA3 (1956 nt). A phylogenetic analysis based on the coat protein amino acid sequences indicated that the novel virus belongs to the same subgroup 3 of the genus Ilarvirus as PNRSV and ApMV. The presence of mosaic leaves, which tend to be unevenly distributed in diseased apple trees, was correlated with the internal distribution of ApNMV. RT-PCR detection of mosaic-diseased apple trees in Japan indicated that ApNMV was detected in apple trees introduced from China, whereas ApMV was detected from cultivated apple trees in domestic orchards. Consistent with these findings, a survey of mosaic-diseased apple trees in major apple-producing provinces in China revealed that the majority of apple trees showing mosaic symptoms in China are infected with ApNMV. [ABSTRACT FROM AUTHOR]

Contigs with sequence homologies to apple chlorotic leaf spot virus (ACLSV) were identified by high-throughput sequencing analysis in three peach samples. Complete genomic sequences of RP19-1 and RP19-2 of the virus consisted of 7,466 and 7,465 nucleotides (nts), respectively, excluding the poly (A) tails. They shared the highest identity with Ta Tao 5, but lower than 70% of sequence similarity with other ACLSV isolates. Furthermore, phylogenetic analysis revealed that these two isolates clustered with Ta Tao 5, which is distinct from other ACLSV isolates. According to the criteria for species demarcation within the genus Trichovirus, these two isolates as well as Ta Tao 5 should be recognized as a new virus species, tentatively named “Peach chlorotic leaf spot virus”. [ABSTRACT FROM AUTHOR]

Potato virus M (PVM, genus Carlavirus, family Betaflexviridae) is considered to be one of most economically important pathogens of pepino in China. However, the details and the mechanisms underlying PVM evolution are unknown. In this study, we determined and analyzed 40 TGB 1 gene sequences, 67 TGB 2 and TGB 3 gene sequences, and 88 CP and NABP gene sequences from viruses isolated from 19 samples of pepino ( Solanum muricatum) and one sample of tomato ( S. lycopersicum) collected from different areas of China. Recombination analysis identified only one clear recombinant in the TGB2-TGB3-CP region, but no recombinants were detected for each of the five individual genes. Phylogenetic analysis showed that all PVM isolates could be divided into at least two lineages in trees derived from the TGB 2, CP, and NABP gene sequences, and the lineages seemed to reflect geographical origin. The five PVM genes in this study were found to be under strong negative selection pressure. The PVM isolates examined showed frequent gene flow between the Chinese and European populations, and also within the Chinese population. Clear star phylogenies and the neutral equilibrium model test showed that pepino isolates of PVM appear to be experiencing a new expansion after a recent introduction into China, and these isolates display low levels of genetic diversity. To our knowledge, this study is the first report describing genetic structure, recombination, and gene flow in PVM populations, and it provides strong evolutionary evidence for the virus populations from different geographic regions of China. [ABSTRACT FROM AUTHOR]

In this study, we generated sequences of the apple chlorotic leaf spot virus (ACLSV) coat protein (CP) gene. Genetic variation and phylogenetic analyses were carried out on these sequences along with others reported previously. ACLSV populations clustered into four types: in three of the four types, combinations of three amino acids at positions of 40, 75 and 79 were conserved. The fourth phylogenetic type, newly identified here, was characterized by co-variation of Ser-Tyr-Ser. Statistically significant genetic differentiation and infrequent gene flow were detected among the four types. Two natural recombinants were detected for the first time among ACLSV isolates/genotypes from China. [ABSTRACT FROM AUTHOR]

Sequences of the protein 1 (P1) and coat protein (CP) coding regions of 22 sugarcane streak mosaic virus (SCSMV) isolates were determined. Phylogenetic analysis showed that SCSMV had at least three major lineages, and the lineages seemed to reflect geographical origin. The sudden expansions of the Chinese and Indian subpopulations were supported by calculations showing deviations from the neutral equilibrium model for the individual lineages with an overall lack of nucleotide diversity. Our study shows that Chinese and Indian SCSMV isolates are part of a distinct population, and the subpopulations probably reflect founder effects. [ABSTRACT FROM AUTHOR]

Potato virus M (PVM), pepino mosaic virus (PepMV), tomato mosaic virus (ToMV), and potato virus S (PVS) infect pepino and cause serious crop losses. In this study, a multiplex RT-PCR method was developed for simultaneous detection and differentiation of PVS, ToMV, PepMV and PVM. The method was highly reliable and sensitive; validation was accomplished by testing pepino samples collected from different regions of China. In this survey, PVM, ToMV and PVS were detected in 37.0 %, 31.0 % and 5.5 % of samples tested, respectively, confirming the widespread occurrence of these three viruses in China. PepMV was not detected in any of the samples, which indicated that this virus may not be prevalent in China. The results suggest that the new multiplex RT-PCR method has potential to be used routinely for surveys of pepino for virus infection. [ABSTRACT FROM AUTHOR]

Two complete nucleotide sequences of cherry green ring mottle virus (CGRMV) isolated from peach in Hebei (Hs10) and Fujian (F9) Provinces, China, were determined. Five open reading frames (ORFs) were found in the genomes of both isolates. The F9 and Hs10 isolates shared 82.2 % and 83.4-94.4 % nucleotide sequence identity, respectively, with two CGRMV isolates from cherry. Analysis of the nucleotide and amino acid sequences from the five ORFs of both isolates showed that Hs10 shares the greatest sequence identity with P1A (GenBank AJ291761) from cherry. Phylogenetic analysis indicated that CGRMV isolates from peach and cherry are closely related to members of the genus Foveavirus. [ABSTRACT FROM AUTHOR]

A survey for the incidence of Hop stunt viroid (HSVd) infection in China was conducted using dot-blot hybridization. Out of 553 tested samples, 127 samples of stone fruits (apricot, peach, plum and almond), grapevine and hop were positive for HSVd, giving a mean infection rate of 23 %. Phylogenetic analysis revealed that most of the HSVd variants isolated from stone fruits, grapevine and hop were clustered into known hop and plum groups. However, two grapevine variants, HSVd.g50 and HSVd.g57, could not be clustered into any known groups, indicating a previously unknown phylogenetic group of HSVd isolates. HSVd.g38 was the single grapevine variant that clustered with the plum group isolates, supporting cross transmission between grapevine and stone fruits and the heterogeneity of grapevine isolates. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequences of two isolates of apple chlorotic leaf spot virus (Z1 and Z3) collected from peach in Henan Province, China, were determined. The genomes of both Z1 and Z3 were found to contain three open reading frames (ORFs). Sequence analysis showed that genomic sequences of Z1 and Z3 isolates shared 67.4%-82.9% and 67.2%-82.6% identity, respectively, with the other eight isolates of ACLSV that have been reported previously. Based on the putative amino acid sequences of the products of the three ORFs, Z1 and Z3 isolates showed the greatest identity to isolate PBM1 (GenBank accession number AJ243438) from plum and the least identity with isolate Ta Tao5 (GenBank Accession Number: EU223295) from peach. Considering the low level of sequence identity between Z1/Z3 isolate and Ta Tao5 isolate, two types of ACLSV may exist in peach. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM), the most common brain tumor in adults, is neurologically destructive and has a dismal response to virtually all therapeutic modalities. One phenomenon that can contribute to this complexity is the presence of a relatively small subset of glioma stem cells (GSCs) within the tumor and the activation of pathways that control cellular differentiation. The Notch signaling pathway, which is responsible for maintaining a balance between cell proliferation and apoptosis, is believed to be deregulated in cancer stem cells (CSCs), leading to tumor growth through the generation or expansion of CSCs. In this study, Notch- 1 small interfering RNA (siRNA) was used to silence Notch- 1 gene expression in GSCs. An MTT assay demonstrated inhibitory effects on the proliferation of GSCs in vitro. Real-time PCR showed that Notch- 1 expression levels were markedly decreased in GSCs transfected with Notch- 1 siRNA in vitro . Notch- 1 silenced GSCs engrafted on Balb/c nude mice showed a significantly greater reduction in oncogenicity than the control group ( P < 0.05). Furthermore, direct intratumoral injections of Notch- 1-siRNA/PEI significantly delayed the growth of pre-established tumors in nude mice ( P < 0.05). These results suggest that siRNA-mediated silencing of the Notch- 1 gene may represent a novel target for gene therapy of GBM. [ABSTRACT FROM AUTHOR]

This study aimed to develop a polyprobe for the simultaneous detection of four viroids that infect grapevine: Hop stunt viroid (HSVd), Australian grapevine viroid (AGVd), Grapevine yellow speckle viroid-1 and 2 (GYSVd-1, 2), using a non-isotopic dot blot hybridization technique. A polyprobe was constructed by cloning tandem full-length sequences of HSVd, AGVd and GYSVd-1 into a single vector. The cRNA polyprobe detected all four viroids with similar sensitivity to that obtained using individual probes. In addition, samples of 78 varieties from Beijing and Xinjiang were analyzed using the polyprobe to survey the incidence of grapevine viroids in China. The result demonstrated that grapevine viroids were detected in 56 (71.8%) varieties. In this study, a rapid, reliable and cost-effective approach to the simultaneous detection of four grapevine viroids has been developed which has the potential for routine use in quarantine and certification programs. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequences of three sugarcane streak mosaic virus (SCSMV) isolates found in sugarcane plants imported from Japan (JP1, JP2) and Indonesia (ID) into China were determined. Sequence analysis showed that, based on the whole genome sequence and the nucleotide sequences encoding the ten mature proteins, the three SCSMV isolates shared identities of 81.62%-81.67% and 76.39%-85.93%, respectively, with a Pakistan (PAK) isolate of SCSMV. Phylogenetic analysis indicated that SCSMV-JP1, -JP2 and -ID were clustered in a subgroup separate from the previously described SCSMV-PAK and -India isolates, and may thus represent a new strain of SCSMV. [ABSTRACT FROM AUTHOR]

The aim of this paper is to construct a specific and high-performance gene therapy system for glioma. We constructed a combined promoter 6HRE-GFAP (Hypoxia Responsive Element, Glial Fibrillary Acidic Protein) by gene recombination techniques according to the hypoxia microenvironment in glioma and tested its efficacy and specificity in cultured cells, and then constructed GFAP-Baxα gene expressing system and determined its promoting of apoptosis in glioma cells. Our primary results showed that in U251 and BT325 cell lines, the activity of GFAP promoter was 16.40 and 4.73-fold of the promoter of hTERT (Human Telomerase Reverse Transcriptase), respectively. The activities of 6HRE-GFAP-promoter increased by 3.08 and 1.30-fold under 2% O2 condition compared with those under 18% O2 condition, while under 0.2% O2 condition increased by 8.90 and 2.69-fold, respectively. The glioma cells showed typical apoptotic signs 90 hours after the transient transfection of GFAP-Baxα. In these primary experiments, it showed that 6HRE-GFAP-Baxα system could promote glioma cell apoptosis. It was specific and effective for glioma gene therapy. [ABSTRACT FROM AUTHOR]

In fission yeast (Schizosaccharomyces pombe), pad gene was cloned with 99.3% nucleotide sequence similarity with published pad in GenBank. In pET-5a expression system, the expression product of cloned pad in E. coli showed activity to degrade the double-strand RNA. Harboring the binary vector pBI121, which contains pad gene, Agrobacterium tumefaciens strain LBA4404 was used to transform the wheat immature embryos pre-cultured 7-10 d. After preregeneration, regeneration and selection culture stage, totally 41 G418 resistant plants were obtained, in which 25 lines were proved to integrate with transgene and express transgene normally by PCR, Dot blot, RT-PCR and ELISA detection. Antivirus test carried out on 25 positive lines with high dose of Barley yellow dwarf virus-GPV revealed that 12 lines had resistance to BVDV-GPV in low level, another 12 lines had resistance to BVDV- GPV in middle level, and 1 line showed resistance to BVDV-GPV in high level. However, both low and middle level of resistance plants showed no symptoms when infected by viruses at low dose, which suggested the dose-dependent effect of the resistance mediated by pad to BYDV-GPV. [ABSTRACT FROM AUTHOR]

Aberrant expression of microRNAs hae been shown to be closely associated with glioblastoma cell proliferation, apoptosis and drug resistance. However, mechanisms underlying the role of mcroRNAs in glioblastoma cell growth and apoptosis are not fully understood. In this study, we report that miR-503 is overexpressed in glioblastoma tissue compared with normal human brain tissue. Mechanistically, miR-503 can be induced by TGF-β1 at the transcriptional level by binding the smad2/3 binding elements in the promoter. Ectopic overexpression of miR-503 promotes cell growth and inhibits apoptosis by targeting PDCD4. In contrast, inhibition of miR-503 reduces cell growth. Furthermore, miR-503 inhibitor augments the growth inhibitory effect of temozolomide in glioblastoma cells. These results establish miR-503 as a promising molecular target for glioblastoma therapy. [ABSTRACT FROM AUTHOR]