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The biggest Phanerozoic mass extinctionoccurred at the Permian-Triassic boundary and resulted in the loss of about 95% or more of all marine species. For quite some time, many kinds of abnormal environmental events were adopted to explain the abnormal reduction of carbon isotope at the Permian-Triassic boundary, however there still has not been a unified opinion. In this paper, based on the carbon cycle balance model of the earth under a long-period scale, the contributions of possible cataclysm events at the Permian-Triassic boundary to the carbon isotope records in carbonates were quantitatively simulated. The results proved that a single event, such as volcanism, terrestrial ecosystem collapse or another factor, was not strong enough to lead to the negative bias of carbon isotope at the Permian-Triassic boundary. Even though the release of methane hydrate can result in a comparably large negative excursion of inorganic carbon, this explanation becomes unsuitable when both the shifting Permian-Triassic boundary and the fluctuation record of other inorganic carbon isotopes in the early Triassic as a whole are considered. Therefore, it is suggested that the dynamic equilibrium between inorganic carbon reserves and organic carbon reserves was possibly disturbed by a superimposed effect of multiple events.

The purpose of the present study was to investigate the correlation between acute heat stress and relevant histopathology and biochemical parameters of kidney function. A total of 80 healthy Arbor Acer (AA) broiler chickens were randomly divided into two groups: CT (Control Temperature; 22±1°C) group and HT (High Temperature; 38±1°C) group. Histopathological images revealed alteration in kidney (renal tubular lumen dilation with tubular necrosis, especially after 10h of heat stress) of broiler chickens in HT group leading to disturbance of acid base balance. Blood urea nitrogen (BUN) and creatinine (CREA) as serum markers of renal dysfunction were elevated significantly (p<0.05) after 5h, and especially, after 10h of heat stress (p<0.01) as compared with CT group. These results indicated that the evaluation of morphological and functional parameters in kidney is required, in order to monitor broiler chickens exposed to heat stress. [ABSTRACT FROM AUTHOR]

In the present study, the effects of melt superheat treatment on the microstructural evolution and wear behaviours of hypereutectic Al-20Si alloy were investigated. The morphology of primary and eutectic Si phase was analysed by optical microscopy (OM) and scanning electron microscopy (SEM). The results of OM and SEM reveal that increasing the melt superheat temperature can significantly refine the primary and eutectic Si of hypereutectic Al-20Si alloy. The average size of primary Si was reduced from 94 to 47 μm, and its morphology was transformed from coarse and irregular shape to fine blocky shape or particles, while the eutectic Si was modified into fine fibrous structure. The differential scanning calorimeter curves show an exothermic reaction happens when the melt temperature arrives at 940·5°C, and the exothermic peak is at 951°C. Friction and wear tests show that the friction coefficient and specific wear rate of Al-20Si alloy gradually decrease with increasing melt superheat treatment temperature. In addition, the wear mechanism of hypereutectic Al-20Si alloy before and after refining the primary and eutectic Si phase was also discussed. [ABSTRACT FROM AUTHOR]

Enterococci are considered as important opportunistic pathogens causing different infections in farm animals. The main aim of the experiment was to describe the prevalence of high-level aminoglycoside resistant (HLAR) Enterococci isolated from Tibetan pigs. In current study, 51 samples were identified by polymerase chain reaction (PCR) followed by testing the high level streptomycin resistance (HLSR) and high level gentamicin resistance (HLGR) by Minimum Inhibitory Concentration (MIC). The aminoglycoside modifying enzyme (AME) genes aac(6')-Ie-aph(2')-Ia, aph(2)-Ic, aph(3)-IIIa, ant(4)-Ia, ant(6')-Ia and ant(3')-(9) in Enterococci were detected by PCR. Results showed that the prevalence of HLSR, HLGR and HLGR + HLSR was found to be 68.6, 76.5, and 39.2% respectively; and ant (4')-Ia and aac(6')-Ie-aph(2')-Ia genes showed 62.7 and 70.6% prevalence, respectively; however, other AME genes were found all negative. In conclusion, the isolates of Enterococci from Tibetan pigs have produced high level resistance to aminoglycoside. [ABSTRACT FROM AUTHOR]

The complete genomic sequence of a Chinese Potato virus X isolate FX21 (PVX-FX21) was determined from three overlapping cDNA clones. The genome of PVX-FX21 is 6435 nucleotides in length excluding the poly(A) tail and contains five open reading frames (ORFs). Its entire genomic sequence shares 95.2–96.3% identities with Asian and European isolates, and 77.3–77.8% with American isolates. Phylogenetic analysis of the complete genomic sequence reveals two groups: the Eurasian group and the American group. PVX-FX21 belongs to the Eurasian group and forms a separate sub-branch with three Asian isolates. Similar analyses of the coat protein genes of 37 PVX isolates also reveal two major groups. All PVX isolates from Asia are clustered to group I, whereas isolates from Europe and America are clustered to both groups. Nucleotide sequence diversity analyses show that there is no geographical differentiation between PVX isolates and that constraint on the ORF encoding RNA-dependent RNA polymerase is much higher than those on the other four ORFs. [ABSTRACT FROM AUTHOR]

In 2005, rose plants ( Rosa rugosa cv. ‘Plena’) exhibiting typical phytoplasma disease symptoms of stunting, yellowing, witches’-broom and dieback were observed in Pingyin, Shandong Province, China. The disease, rose witches’-broom (RoWB), is progressively destructive and can be graft-transmitted. Polymerase chain reaction (PCR), sequencing of PCR products and electron microscopy were used to investigate the possible association of phytoplasma with RoWB. All results indicated that presence of phytoplasma in the symptomatic rose plants. Sequence alignment of 16S rRNA gene, tuf gene and rp gene confirmed that the phytoplasma associated with RoWB is the causal agent of Paulownia witches’-broom disease, which might be transmitted from the paulownia tree that is several meters away. To our knowledge, this is the first report of the molecular characterization of phytoplasma infecting rose in China. [ABSTRACT FROM AUTHOR]

Temozolomide (TMZ) resistance is an important cause of clinical treatment failure and poor prognosis in gliomas. Increasing evidence indicates that cancer-derived exosomes contribute to chemoresistance; however, the specific contribution of glioma-derived exosomes remains unclear. The aim of this study was to explore the role and underlying mechanisms of exosomal macrophage migration inhibitory factor (MIF) on TMZ resistance in gliomas. We first demonstrated that MIF was upregulated in the exosomes of TMZ-resistant cells, engendering the transfer of TMZ resistance to sensitive cells. Our results indicated that exosomal MIF conferred TMZ resistance to sensitive cells through the enhancement of cell proliferation and the repression of cell apoptosis upon TMZ exposure. MIF knockdown enhanced TMZ sensitivity in resistant glioma cells by upregulating Metalloproteinase Inhibitor 3 (TIMP3) and subsequently suppressing the PI3K/AKT signaling pathway. Additionally, exosomal MIF promoted tumor growth and TMZ resistance of glioma cells in vivo , while IOS-1 (MIF inhibitor) promotes glioma TMZ sensitive in vivo . Taken together, our study demonstrated that exosome-mediated transfer of MIF enhanced TMZ resistance in glioma through downregulating TIMP3 and further activating the PI3K/AKT signaling pathway, highlighting a prognostic biomarker and promising therapeutic target for TMZ treatment in gliomas., Competing Interests: The authors declare no competing interests., (© 2021 The Authors.)

The current study was performed to investigate the prevalence, associated risk factors exploration and phylogenetic analysis of Echinococcus granulosus (E. granulosus) genotypes isolated from Tibetan pigs. A total 373 Tibetan pigs were examined during 2014 and 2015, and the variables potentially associated with E. granulosus infection were explored with a multivariable logistic regression model. E. granulosus cysts (n=37) were collected from Tibetan pigs (lungs or livers). Fragments amplification of mitochondrial (mt) DNA of cox1 (shorter and longer) and atp6 were employed. The genotype of E. granulosus were identified by sequence and phylogenetic analysis. Results showed the prevalence of E. granulosus in Tibetan pigs was 9.9%. The prevalence of E. granulosus in male and female Tibetan pigs was 6.8% and 13.3%, with a significant difference in the two genders (P<0.05). In different seasons, the infection rate of E. granulosus in Tibetan pigs were ranged from 5.8% to 12.3%. E. granulosus infection rates in different growing stages of Tibetan pigs were ranged from 4.4% to 15.9%, with a statistical difference in the three stages (P<0.01). The prevalence of E. granulosus in Tibetan pigs were 7.9% in 2014 and 13.0% in 2015. Genders and growing stages were demonstrated to be risk factors to influence the prevalence significantly through multivariable logistic regression model. All the three fragments were successfully amplified from each of the 37 cysts. E. granulosus genotypes of G4 and G6 were identified by comparing with reference sequences of E. genotypes available at NCBI database and phylogenetic analysis by using MEGA software.

Cucumber mosaic virus (CMV) isolates are currently divided into two main groups, I and II according to their genomic sequences. The group I is further divided into two subgroups IA and IB. We performed a phylogenetic analysis of the genome regions containing 1a, 2a, 2b, coat protein (CP), and movement protein (MP) genes of 5 CMV isolates from China and other 28 CMV isolates available in the GenBank. The results indicated that CMV isolates could be genetically divided into three groups I, II, and III according to the genes encoding MP, CP, 1a, and 2a proteins and to the 2 groups according to the gene 2b. Group I could be further divided into two subgroups (IA and IB) according to the genes encoding CP, MP, 2a, and 2b proteins and to the three subgroups (IA, IB, and IC) according to the gene encoding 1a protein. Four of 5 examined Chinese CMV isolates belonged to the subgroup IB, while the remaining isolate was a natural inter-subgroup reassortant. We found that the 2b gene of CMV was under positive selection, while the other genes were under negative selection. No evidence of the selection associated with a host adaptation or geographic distribution was found.

The effect of valvular and subvalvular morphologic features and balloon size/mitral anulus size ratio on results of valvuloplasty were prospectively studied in 38 consecutive patients undergoing mitral valvuloplasty. The severity of valvular and subvalvular disease was graded echocardiographically from grade I to IV (mild to severe) for immobility, thickening, calcification of mitral leaflets and subvalvular thickening and fusion, yielding a maximal total score of 16. The diastolic mitral anulus diameter was measured in the apical four chamber view. After valvuloplasty, the mitral valve area increased from 0.9 +/- 0.3 to 2.2 +/- 0.5 cm2 (p less than 0.001) with increasing mitral regurgitation in 12 (32%) of the 38 patients. Multiple stepwise analysis revealed that the ratio of balloon size and annular size and the severity of subvalvular disease are two independent factors that correlated significantly with the mitral valve area after valvuloplasty (multiple r = 0.65, p less than 0.0002). One of 34 patients with mild subvalvular disease of grade III or less had an unsatisfactory increase in mitral valve area to less than or equal to 1.5 cm2, whereas 3 of 4 patients with severe (grade IV) subvalvular disease had a valve area less than or equal to 1.5 cm2 (p less than 0.002) after valvuloplasty. The increase in mitral regurgitation after valvuloplasty correlated significantly with the ratio of balloon to mitral anulus size and the severity of subvalvular disease (multiple r = 0.53, p less than 0.003). (ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous balloon valvotomy by means of a new sequential single- and and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dilatation procedure was initially performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two balloons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dilatation was successful in all patients; the mitral valve pressure gradient decreased from 19 +/ 6 to 5 +/ 2 mm Hg, the cardiac output increased from 4.0 +/ 0.5 to 5.2 +/ 0.6 L/min, and the MVA increased from 0.8 +/ 0.2 to 1.9 +/ 0.4 cm2 (p less than 0.01 each). The MVA after dilatation was relative to the effective balloon dilatation diameter selected (r = 0.57; p less 0.01). A small atrial septal defect was observed in 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced in 3 of 23 patients by the dilatation. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamics in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 +/ 18 mm of two balloons) is necessary for effective dilatation.