Solar-driven photocatalysis with charge-transfer modulation is a green approach for enhancing the oxygen reduction reaction(ORR)to generate hydrogen peroxide(H_(2)O_(2)).In this study,we introduced a novel method for ...Solar-driven photocatalysis with charge-transfer modulation is a green approach for enhancing the oxygen reduction reaction(ORR)to generate hydrogen peroxide(H_(2)O_(2)).In this study,we introduced a novel method for synthesizing high-valence Sn^(δ+)in SnS_(2),combined with gC_(3)N_(4)to create gC_(3)N_(4)/SnS_(2).Density functional theory(DFT)calculations exhibited that the interface between SnS_(2)and gC_(3)N_(4)creates interband states through strong hybridization,revealing that photoexcited electrons flowed from C in gC_(3)N_(4)to S in SnS_(2),forming a Z-scheme heterojunction.The optimal gC_(3)N_(4)/SnS_(2)-2(2%SnS_(2)loaded)achieved a high H_(2)O_(2)production rate of 7.186 mmol g^(-1)h^(-1)and an apparent quantum efficiency(AQE)of 33.8%at 405 nm with isopropanol(IPA),converting 88.8%IPA to acetone in 2 h.The gC_(3)N_(4)/SnS_(2)composite improved the charge transfer resistance and elongated the non-radiative electron decay time.Notably,SnS_(2)doping of gC_(3)N_(4)decreased the antibonding orbital occupancy and lowered the energy barrier for O_(2) and OOH^(*)adsorption.In situ surface-enhanced Raman spectroscopy(SERS)analysis confirmed the generation of OOH^(*)on gC_(3)N_(4)/SnS_(2)during light irradiation.A techno-economic analysis(TEA)was conducted to evaluate the economic viability of photocatalytic H_(2)O_(2)production,revealing that it was not economically feasible owing to challenges in the separation process.This study provides unique perspectives on the approaches to inducing a high valence state of Sn^(δ+)for enhancing photocatalytic H_(2)O_(2)generation and the challenge of commercializing H_(2)O_(2)production via photocatalysis.展开更多
Blastopsylla occidentalis Taylor是原产于澳大利亚的木虱种类,目前已经扩散到北美、南美、非洲、欧洲和亚洲。本文记述了B.occidentalis在中国的发生,并首次记录了其在澳大利亚以外的地区被寄生。这个种依赖于桉属Eucalyptus植物,其...Blastopsylla occidentalis Taylor是原产于澳大利亚的木虱种类,目前已经扩散到北美、南美、非洲、欧洲和亚洲。本文记述了B.occidentalis在中国的发生,并首次记录了其在澳大利亚以外的地区被寄生。这个种依赖于桉属Eucalyptus植物,其寄主超过20种,这可能是使其在世界范围扩散的一个重要因素。指出了B.occidentalis与桉树芽木虱Blastopsylla barbara Li为同种异名。展开更多
AIM: To investigate p53 mutation and p21 expression in hepatocarcinogenesis induced by hepatitis B virus (HBV) and aflatoxin B1 (AFB1) in tree shrews, and to reveal the role of these genes in hepatocarcinogenesis.METH...AIM: To investigate p53 mutation and p21 expression in hepatocarcinogenesis induced by hepatitis B virus (HBV) and aflatoxin B1 (AFB1) in tree shrews, and to reveal the role of these genes in hepatocarcinogenesis.METHODS: Tree shrews were divided into four groups:group A, those infected with HBV and fed with AFB1 (n = 39);group B, those infected with HBV alone (n = 28); group C,those fed with AFB1 alone (n = 29); and group D, normal controls (n = 20). The tree shrews underwent liver biopsies once every 15 wk. Expression of p53 and p21 proteins and genes in the biopsies and tumor tissues of the experimental tree shrews was detected, respectively, by immunohistochemistry,and by Southem blotting and reverse transcription-polymerase chain reaction and sequencing.RESULTS: The incidence of hepatocellular carcinomas (HCC) was higher in group A (66.7%) than that in group B (3.57%) and C (30%). The time of HCC occurrence was also earlier in group A than that in group C (120.0±16.6 wk vs 153.3±5.8 wk, respectively, P<0.01). p53 protein was not detected by immunohistochemistry in all groups before the 75^th wk of the experiment. At the 105^th wk, the positive rates fo p53 were 78.6%, 60% and 71.4% in groups A, B and C, respectively, which were significantly higher than that in group D (10%) (all P<0.05). An abnormal band of p53 gene was observed in groups A and C. The mutation points of p53gene in tree shrews with HCC were at codons 275, 78 and 13. The nucleotide sequence and amino acid sequence of tree shrew's wild-type p53 showed 91.7% and 93.4% homologies with those of human p53,respectively. The immunopositivity for p21 was found before HCC development. The incidence of HCC was significantly higher in tree shrews that were positive for p21 than those negative for p21 (80.0% vs 11.0%, P<0.001).The incidence of HCC in p21 positive animals in group A was significantly higher than those positive for p21 in group C (P<O.05).CONCLUSION: A remarkable synergistic effect on HCC development exists between HBV and AFB1. p53 mutation promotes the development of HCC. HBV and AFB1 may synergistically induce p53 gene mutation, and stimulate ras gene expression, ras gene is activated at the earlier stage during hepatocarcinogenesis, p21 protein may be an early marker, and the alterations of p53 may be a late event in the development of HCC.展开更多
Background: Feed accounts for up to 75% of costs in beef production systems,thus any improvement in feed efficiency(FE) will benefit the profitability of this enterprise.Residual feed intake(RFI) is a measure of FE th...Background: Feed accounts for up to 75% of costs in beef production systems,thus any improvement in feed efficiency(FE) will benefit the profitability of this enterprise.Residual feed intake(RFI) is a measure of FE that is independent of level of production.Adipose tissue(AT) is a major endocrine organ and the primary metabolic energy reservoir.It modulates a variety of processes related to FE such as lipid metabolism and glucose homeostasis and thus measures of inter-animal variation in adiposity are frequently included in the calculation of the RFI index.The aim of this study was to determine the effect of phenotypic RFI status and gender on the expression of key candidate genes related to processes involved in energy metabolism within AT.Dry matter intake(DMI) and average daily gain(ADG) were measured over a period of 70 d for 52 purebred Simmental heifers(n = 24) and bulls(n = 28) with an initial BW±SD of 372±39.6 kg and 387±50.6 kg,respectively.Residual feed intake was calculated and animals were ranked within gender by RFI into high(inefficient; n = 9 heifers and n = 8 bulls)and low(efficient; n = 9 heifers and n = 8 bulls) groups.Results: Average daily gain ±SD and daily DMI ±SD for heifers and bul s were 1.2±0.4 kg and 9.1±0.5 kg,and 1.8±0.3 kg and 9.5±1 kg respectively.High RFI heifers and bulls consumed 10% and 15% more(P < 0.05) than their low RFI counterparts,respectively.Heifers had a higher expression of all genes measured than bulls(P < 0.05).A gender × RFI interaction was detected for HMGCS2(P < 0.05) in which high RFI bulls tended to have lower expression of HMGCS2 than low RFI bulls(P < 0.1),whereas high RFI heifers had higher expression than low RFI heifers(P < 0.05) and high RFI bulls(P < 0.05).SLC2 A4 expression was consistently higher in subcutaneous AT of low RFI animals across gender.Conclusion: The findings of this study indicate that low RFI cattle exhibit upregulation of the molecular mechanisms governing glucose metabolism in adipose tissue,in particular,glucose clearance.The decreased expression of SLC2 A4 in the inefficient cattle may result in less efficient glucose metabolism in these animals.We conclude that SLC2 A4 may be a potential biomarker for RFI in cattle.展开更多
Antimicrobial delivery has been advocated for guided tissue regeneration (GTR) or guided bone regeneration (GBR) therapies involving patients with aggressive or unresolved periodontitis/peri-implantitis. Electrospun c...Antimicrobial delivery has been advocated for guided tissue regeneration (GTR) or guided bone regeneration (GBR) therapies involving patients with aggressive or unresolved periodontitis/peri-implantitis. Electrospun chitosan membranes demonstrate several advantages over traditional GTR barrier membranes because they stimulate healing, mimic the topology of the extracellular matrix, and allow for diffusion of nutrients and wastes into/out of the graft site, and were shown to stimulate bone formation in a rabbit calvarial criticalsize defect model. Previously, we have shown improvements in mechanical properties and degradation kinetics by crosslinking electrospun membranes with 5 mM or 10 mM genipin. We have also demonstrated the ability of elecrospun chitosan membranes to inhibit lippopolysaccharide (LPS)-induced monocyte activation. In this study, minocycline was incorporated into the chitosan membrane by passive absorption at 5 or 10 mg/mL. The minocycline-loaded membranes and control membranes (carrier only) were tested against Porphyromonas gingivalis (P. gingivalis) by repeated zone of inhibition (ZOI) measurements. Testing showed that uncrosslinked and genipin-crosslinked membranes have similar capacity to absorb aqueous solutions (swelling ratio 1.7 - 2.2). Minocycline loading resulted in bacterial inhibition for up to 8 days from crosslinked membranes (with 11 mm initial ZOI) whereas uncrosslinked membranes loaded with minocycline only inhibited bacteria for 4 days (with 8 mm initial ZOI). These in vitro results suggest that genipin-crosslinked electrospun chitosan membranes loaded with minocycline may be able to reduce early bacterial contamination of GTR graft sites.展开更多
Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host...Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency.The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） diet.Ruminal fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary periods.Quantitative real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes.Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet digestibility.Results：Abundance of methanogens,did not differ between RFI phenotypes.However,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF diet.Conclusions：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.展开更多
The measurement of atmospheric O_(2)concentrations and related oxygen budget have been used to estimate terrestrial and oceanic carbon uptake.However,a discrepancy remains in assessments of O_(2)exchange between ocean...The measurement of atmospheric O_(2)concentrations and related oxygen budget have been used to estimate terrestrial and oceanic carbon uptake.However,a discrepancy remains in assessments of O_(2)exchange between ocean and atmosphere(i.e.air-sea O_(2)flux),which is one of the major contributors to uncertainties in the O_(2)-based estimations of the carbon uptake.Here,we explore the variability of air-sea O_(2)flux with the use of outputs from Coupled Model Intercomparison Project phase 6(CMIP6).The simulated air-sea O_(2)flux exhibits an obvious warming-induced upward trend(~1.49 Tmol yr−2)since the mid-1980s,accompanied by a strong decadal variability dominated by oceanic climate modes.We subsequently revise the O_(2)-based carbon uptakes in response to this changing air-sea O_(2)flux.Our results show that,for the 1990−2000 period,the averaged net ocean and land sinks are 2.10±0.43 and 1.14±0.52 GtC yr−1 respectively,overall consistent with estimates derived by the Global Carbon Project(GCP).An enhanced carbon uptake is found in both land and ocean after year 2000,reflecting the modification of carbon cycle under human activities.Results derived from CMIP5 simulations also investigated in the study allow for comparisons from which we can see the vital importance of oxygen dataset on carbon uptake estimations.展开更多
Background:Previous research in both calves and other species has suggested n-3 polyunsaturated fatty acids(PUFA)andβ-glucans may have positive effects on immune function.This experiment measured performance,behaviou...Background:Previous research in both calves and other species has suggested n-3 polyunsaturated fatty acids(PUFA)andβ-glucans may have positive effects on immune function.This experiment measured performance,behaviour,metabolite and immunological responses to pre-weaning supplementation of dairy bull calves with n-3 PUFA in the form of fish oil andβ-glucans derived from seaweed extract.44 Holstein Friesian bull calves,aged 13.7±2.5 d and weighing 48.0±5.8 kg were artificially reared using an electronic feeding system.Each calf was offered5 L(120 g/L)per day of milk replacer(MR)and assigned to one of four treatments included in the MR,(1)Control(CON);(2)40 g n-3 PUFA per day(FO);(3)1 gβ-glucans per day(GL)and(4)40 g n-3 PUFA per day&1 g/dβ-glucans(FOGL)in a 2×2 factorial design.Milk replacer and concentrate was offered from d 0–62(pre-weaning),while concentrate provision continued for a further 31 d post-weaning period.Individual daily feed intake and feeding behaviour was recorded throughout,while bodyweight and blood analyte data were collected at regular intervals.Results:Overall mean concentrate DMI from d 0–93 was 1.39,1.27,1.00 and 0.72 kg/d for CON,FO,GL and FOGL calves,respectively(SEM=0.037;P<0.0001).Calves supplemented with GL were significantly lighter(P<0.0001)at both weaning(d 62)and turnout to pasture(d 93)than un-supplemented calves,with a similar effect(P<0.0001)evident for calves receiving FO compared to un-supplemented contemporaries.Supplementation with GL reduced the number of unrewarded visits where milk was not consumed(P<0.0001)while supplementation with FO increased mean drinking speed(P<0.0001).Supplementation with GL resulted in greater concentrations of haptoglobin(P=0.034),greater serum osmolality(P=0.021)and lower lymphocyte levels(P=0.027).In addition,cells from GL supplemented calves exhibited a lower response than un-supplemented contemporaries to both Phytohaemagglutinin A stimulated IFN-γ(P=0.019)and Concanavalin A stimulated IFN-γ(P=0.012)following in vitro challenges.Conclusions:Pre-weaning supplementation of bull calves with either n-3 PUFA orβ-glucan resulted in reduced voluntary feed intake of concentrate and consequently poorer pre-weaning calf performance.There was no evidence for any beneficial effect of either supplementation strategy on calves’immune responses.展开更多
The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter（OM）.Sampling of the liquid layer for 14...The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter（OM）.Sampling of the liquid layer for 14 days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4 hr,and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336 hr. Sorption to soil was the major fate for ractopamine in soil：water systems, i.e., 42%–51% of the dose at14 days. The major portion of the sorbed fraction was comprised of non-extractables; a smaller fraction of the sorbed dose was extracted into water and acetone, portions which would be potentially mobile in the environment. Partitioning coefficients for all soils suggested strong sorption of ractopamine to soil which is governed by hydrophobic interactions and cation exchange complexes within the soil OM. Ractopamine degradation was observed, but to mostly non-polar compounds which had a higher potential than ractopamine to sorb to soil. The formation of volatiles was also suggested. Therefore, despite rapid and extensive soil sorption,these studies indicated a portion of ractopamine, present in manures used to fertilize soils,may be mobile in the environment via water-borne events.展开更多
Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was...Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was conducted with alfalfa（Medicago sativa） and wheat（Triticum aestivum） grown in two soils having different concentrations of organic matter（1.3% and 2.1%）, amended with 0, 0.5, and 10 μg/g of ractopamine. Plant growth ranged from 2.7 to 8.8 g dry weight（dw） for alfalfa, and 8.7 to 40 g dw for wheat and was generally greater in the higher organic matter content soil. The uptake of ractopamine in plant tissues ranged from non-detectable to 897 ng/g and was strongly dependent on soil ractopamine concentration across soil and plant tissue. When adjusted to the total fortified quantities, the amount of ractopamine taken up by the plant tissue was low, 〈 0.01% for either soil.展开更多
Chitosan nanofiber membranes have been known to have a high degree of biocompatibility and support new bone formation with controllable biodegradation. The surface area of these membranes may allow them to serve as lo...Chitosan nanofiber membranes have been known to have a high degree of biocompatibility and support new bone formation with controllable biodegradation. The surface area of these membranes may allow them to serve as local delivery carriers for different biologic mediators. Simvastatin, a drug commonly used for lowering cholesterol, has demonstrated promising bone regenerative capability. The aim of this study was to evaluate simvastatin loaded chitosan nanofiber membranes for guided bone regeneration (GBR) applications and their ability to enhance bone formation in rat calvarial defects. Nanofibrous chitosan membranes with random fiber orientation were fabricated by electrospinning technique and loaded with 0.25 mg of simvastatin under sterile conditions. One membrane was implanted subperiosteally to cover an 8 mm diameter critical size calvarial defect. Two groups: 1) Control: non-loaded chitosan membranes;2) Experimental: chitosan membranes loaded with 0.25 mg of simvastatin were evaluated histologically and via micro-computed tomography (micro-CT) for bone formation at 4 and 8 weeks time points (n = 5/group per time point). Both groups exhibited good biocompatibility with only mild or moderate inflammatory response during the healing process. Histologic and micro-CT evaluations confirmed bone formation in calvarial defects as early as 4 weeks using control and experimental membranes. In addition, newly-formed bony bridges consolidating calvarial defects histologically along with partial radiographic defect coverage were observed at 8 weeks in both groups. Although control and experimental groups demonstrated no significant statistical differences in results of bone formation, biodegradable chitosan nanofiber membranes loaded with simvastatin showed a promising regenerative potential as a barrier material for guided bone regeneration applications.展开更多
Background:Cotton fiber maturity is an important property that partially determines the processing and performance of cotton.Due to difficulties of obtaining fiber maturity values accurately from every plant of a gene...Background:Cotton fiber maturity is an important property that partially determines the processing and performance of cotton.Due to difficulties of obtaining fiber maturity values accurately from every plant of a genetic population,cotton geneticists often use micronaire(MIC) and/or lint percentage for classifying immature phenotypes from mature fiber phenotyp es although they are complex fiber traits.The recent development of an algorithm for determining cotton fiber maturity(MIR)from Fourier transform infrared(FT-IR)spectra explores a novel way to measure fiber maturity efficiently and accurately.However,the algorithm has not been tested with a genetic population consisting of a large number of progeny pla,nts.Results:The merits and limits of the MIC-or lint percentage-bas ed phenotyping method were demonstrated by comparing the observed phenotypes with the predicted phenotypes based on their DNA marker genotypes in a genetic population consisting of 708 F2 plants with various fiber maturity.The observed MIC-based fiber phenotypes matched to the predicted phenotypes better than the observed lint percenta ge-based fiber phenotypes.The lint percentage was obtained from each of F2 plants,whereas the MIC values were unable to be obtained from the entire population since certain F2 plants produced insufficient fiber mass for their measurements.To test the feasibiility of cotton fiber infrared maturity(MIR)as a viable phenotyping tool for genetic analyses,we me asured FT-IR spectra from the second population composed of 80 F2 plants with various fiber maturities,determined MIR values using the algorithms,and compared them with their genotypes in addition to other fiber phenotypes.The results showed that MIR values were successfully obtained from each of the F2 plants,and the observed MIR-based phenotypes fit well to the predicted phenotypes based on their DNA marker genotypes as well as the observed phenotypes based on a combination of MIC and lint percentage.Conclusions:The M,R value obtained from FT-IR spectra of cotton fibers is able to accurately assess fiber maturity of all plants of a population in a quantitative way.The technique provides an option for cotton geneticists to determine fiber maturity rapidly and efficiently.展开更多
Background： The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolis...Background： The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls（mean liveweight 370 ± 35 kg;mean age 479 ± 15 d） were assigned to one of two groups：（i） restricted feed allowance（RES; n = 30） for 125 d（Period 1） followed by ad libitum access to feed for 55 d（Period 2） or（ii） ad libitum access to feed throughout（ADLIB; n = 30）. Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography.Results： Diet × period interactions were evident for genes involved in ketogenesis（BDH2, P = 0.017）, pyruvate metabolism（LDHa, P = 0.048; PDHA1, P = 0.015） and cellular transport and structure（DSG1, P = 0.019; CACT, P = 0.027）. Ruminal concentrations of propionic acid（P = 0.018） and n-valeric acid（P = 0.029） were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency（P = 0.064）toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1.Conclusions： These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.展开更多
The influence of chitosaccharides on the symbiotic interaction between Bradyrhizobium and soybean was examined. The results show that chitosaccharides either positively or negatively affect soybean nodulation or plant...The influence of chitosaccharides on the symbiotic interaction between Bradyrhizobium and soybean was examined. The results show that chitosaccharides either positively or negatively affect soybean nodulation or plant growth depending on their molecular weight, concentration and the application methods. When directly added to the in vitro culture media, chitosan of high molecular weight inhibit Bradyrhizobium viability in a dose dependent manner while chitooligosaccharides reduce slightly the bacteria viability only at concentration equal or higher than 50 mg·L<sup>-1</sup>. Chitooligosaccharides significantly enhance nodule formation and dry mass in soybean roots at doses between 10 and 100 mg·L<sup>-1</sup>. Both types of chitosaccharides, at the highest doses (>500 mg·L<sup>-1</sup>), negatively affect plant height and root size, whereas medium doses (50 to 100 mg·L<sup>-1</sup>) increase slightly leave number. Under field conditions, foliar application of both chitosaccharides enhances growth and nodulation of soybean plants. Nevertheless, using this application method, chitosan remains more effective than chitooligosaccharides.展开更多
OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups:...OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups: group A, infected with HBV and fed with AFB_1; group B, only infected with HBV; group C, fed with AFB_1 alone; and group D normal control. The tree shrews underwent liver biopsy every. 15 weeks. Liver and tumor tissues were detected by immunohistochemistry and molecular biotechnologies. RESULTS: The incidence of hepatocellular carcinoma (HCC) was higher in group A (66.7%) than in groups B (0) and C (30%). HCC occurrence was earlier in group A than in group C (120.0±16.6 wk vs 153.3±5.8 wk, t=3.336, P<0.01). Mutated p53 protein was not found in all groups before 75 weeks of experiment. At the 105th week, the expression rates of mutated p53 protein were 78.6%, 60.0% and 71.4% in groups A, B and C respectively, which were significantly higher than that in group D (10%) (X^2≥5.03, P<0.05). An abnormal band of the p53 gene was detected in groups A and C. The mutational points of the p53 gene in liver cancer of tree shrews were at codon 275, 78 and 13. Nucleotide sequence and amino acids sequence of tree shrew's wild-type p53 were 91.7% and 93.4% in homology, compared with those of human p53, respectively. CONCLUSIONS: Remarkable synergistic effect on HCC exists between HBV and AFB_1. Mutated p53 protein expressed before occurrence of HCC promotes the development of HCC. HBV and AFB_1 may synergistically induce p53 gene mutation.展开更多
Background： Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This stud...Background： Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This study examined gene transcript abundance of important classes of nutrient transporters in the duodenum of non lactating dairy cows of different feed efficiency potential, namely Holstein-Friesian （HF）, Jersey （JE） and their F1 hybrid. Duodenal epithelial tissue was collected at slaughter and stored at -80℃. Total RNA was extracted from tissue and reverse transcribed to generate cDNA. Gene expression of the following transporters, namely nucleoside amino acid; sugar; mineral; and lipid transporters was measured using quantitative real-time RT-PCR. Data were statistically analysed using mixed models ANOVA in SAS. Orthogonal contrasts were used to test for potential heterotic effects and spearman correlation coefficients calculated to determine potential associations amongst gen, expression values and production efficiency variables. Results： While there were no direct effects of genotype on expression values for any of the genes examined, there was evidence for a heterotic effect （P 〈 0.05） on ABCGS, in the form of increased expression in the F1 genotype compared to either of the two parent breeds. Additionally, a tendency for increased expression of the amino acid transporters, SLC3A1 （P= 0.072）, SLC3A2 （P= 0.081） and SLC6A 14 （P= 0.072） was also evident in the F1 genotype. A negative （P 〈 0.05） association was identified between the expression of the glucose transporter gene SLCSA1 and total lactational milk solids yield, corrected for body weight. Positive correlations （P 〈 0.05） were also observed between the expression values of genes involved in common transporter roles. Conclusion： This study suggests that differences in the expression of sterol and amino acid transporters in the duodenum could contribute towards the documented differences in feed efficiency between HF, JE and their F1 hybrid. Furthermore, positive associations between the expression of genes involved in common transporter roles suggest that these may be co-regulated. The study identifies potential candidates for investigation of genetic variants regulating nutrient transport and absorption in the duodenum in dairy cows, which may be incorporated into future breeding programmes.展开更多
Previously we identified a major cotton fiber strength QTL(qFS-c7-1)on chromosome A07 using a multiparent advanced generation intercross(MAGIC)population.To assess the stability and transferability of this QTL and its...Previously we identified a major cotton fiber strength QTL(qFS-c7-1)on chromosome A07 using a multiparent advanced generation intercross(MAGIC)population.To assess the stability and transferability of this QTL and its utility in cotton breeding,we made ten new populations.These populations were developed from crosses between MAGIC recombinant inbred lines,or between cotton cultivars that are different from the MAGIC parents.A total of 2801 F_(2) plants were grown and their fiber quality traits were measured.We also selected a subset of F_(3) seeds from two populations,and grew F_(3) progeny plots to further evaluate the stability of this QTL.Our results showed that the peak of qFS-c7-1 is at 70–72 Mb region.This QTL had a major effect on fiber strength explaining 21.9%phenotypic variance.Its effect on other fiber quality attributes such as micronaire,short fiber content,length and uniformity varied between populations,and no effect on fiber elongation was observed.The QTL effects were stable in the populations analyzed,and in different generations of the same population.The SSR and SNP markers near and within the QTL peak reported herein will assist selecting superior fiber quality traits in breeding,with a recommendation that the parental cotton lines should be analyzed using the seven DNA markers within the QTL peak before fully implementing marker assisted selection in a cotton breeding program.展开更多
基金supported by the National Research Foundation of South Korea(NRF)grant funded by the Korean government(Grant No.2021R1A6A1A03038785,2023R1A2C1003464,RS-2024-00512818 and RS-2023-00240726)。
文摘Solar-driven photocatalysis with charge-transfer modulation is a green approach for enhancing the oxygen reduction reaction(ORR)to generate hydrogen peroxide(H_(2)O_(2)).In this study,we introduced a novel method for synthesizing high-valence Sn^(δ+)in SnS_(2),combined with gC_(3)N_(4)to create gC_(3)N_(4)/SnS_(2).Density functional theory(DFT)calculations exhibited that the interface between SnS_(2)and gC_(3)N_(4)creates interband states through strong hybridization,revealing that photoexcited electrons flowed from C in gC_(3)N_(4)to S in SnS_(2),forming a Z-scheme heterojunction.The optimal gC_(3)N_(4)/SnS_(2)-2(2%SnS_(2)loaded)achieved a high H_(2)O_(2)production rate of 7.186 mmol g^(-1)h^(-1)and an apparent quantum efficiency(AQE)of 33.8%at 405 nm with isopropanol(IPA),converting 88.8%IPA to acetone in 2 h.The gC_(3)N_(4)/SnS_(2)composite improved the charge transfer resistance and elongated the non-radiative electron decay time.Notably,SnS_(2)doping of gC_(3)N_(4)decreased the antibonding orbital occupancy and lowered the energy barrier for O_(2) and OOH^(*)adsorption.In situ surface-enhanced Raman spectroscopy(SERS)analysis confirmed the generation of OOH^(*)on gC_(3)N_(4)/SnS_(2)during light irradiation.A techno-economic analysis(TEA)was conducted to evaluate the economic viability of photocatalytic H_(2)O_(2)production,revealing that it was not economically feasible owing to challenges in the separation process.This study provides unique perspectives on the approaches to inducing a high valence state of Sn^(δ+)for enhancing photocatalytic H_(2)O_(2)generation and the challenge of commercializing H_(2)O_(2)production via photocatalysis.
文摘Blastopsylla occidentalis Taylor是原产于澳大利亚的木虱种类,目前已经扩散到北美、南美、非洲、欧洲和亚洲。本文记述了B.occidentalis在中国的发生,并首次记录了其在澳大利亚以外的地区被寄生。这个种依赖于桉属Eucalyptus植物,其寄主超过20种,这可能是使其在世界范围扩散的一个重要因素。指出了B.occidentalis与桉树芽木虱Blastopsylla barbara Li为同种异名。
基金Supported by the National Natural Science Foundation of China,No.39260033Natural Science Foundation of Guangxi,No.0143058
文摘AIM: To investigate p53 mutation and p21 expression in hepatocarcinogenesis induced by hepatitis B virus (HBV) and aflatoxin B1 (AFB1) in tree shrews, and to reveal the role of these genes in hepatocarcinogenesis.METHODS: Tree shrews were divided into four groups:group A, those infected with HBV and fed with AFB1 (n = 39);group B, those infected with HBV alone (n = 28); group C,those fed with AFB1 alone (n = 29); and group D, normal controls (n = 20). The tree shrews underwent liver biopsies once every 15 wk. Expression of p53 and p21 proteins and genes in the biopsies and tumor tissues of the experimental tree shrews was detected, respectively, by immunohistochemistry,and by Southem blotting and reverse transcription-polymerase chain reaction and sequencing.RESULTS: The incidence of hepatocellular carcinomas (HCC) was higher in group A (66.7%) than that in group B (3.57%) and C (30%). The time of HCC occurrence was also earlier in group A than that in group C (120.0±16.6 wk vs 153.3±5.8 wk, respectively, P<0.01). p53 protein was not detected by immunohistochemistry in all groups before the 75^th wk of the experiment. At the 105^th wk, the positive rates fo p53 were 78.6%, 60% and 71.4% in groups A, B and C, respectively, which were significantly higher than that in group D (10%) (all P<0.05). An abnormal band of p53 gene was observed in groups A and C. The mutation points of p53gene in tree shrews with HCC were at codons 275, 78 and 13. The nucleotide sequence and amino acid sequence of tree shrew's wild-type p53 showed 91.7% and 93.4% homologies with those of human p53,respectively. The immunopositivity for p21 was found before HCC development. The incidence of HCC was significantly higher in tree shrews that were positive for p21 than those negative for p21 (80.0% vs 11.0%, P<0.001).The incidence of HCC in p21 positive animals in group A was significantly higher than those positive for p21 in group C (P<O.05).CONCLUSION: A remarkable synergistic effect on HCC development exists between HBV and AFB1. p53 mutation promotes the development of HCC. HBV and AFB1 may synergistically induce p53 gene mutation, and stimulate ras gene expression, ras gene is activated at the earlier stage during hepatocarcinogenesis, p21 protein may be an early marker, and the alterations of p53 may be a late event in the development of HCC.
基金funded through The Teagasc Walsh Fellowship programme(Project RMIS:6092)
文摘Background: Feed accounts for up to 75% of costs in beef production systems,thus any improvement in feed efficiency(FE) will benefit the profitability of this enterprise.Residual feed intake(RFI) is a measure of FE that is independent of level of production.Adipose tissue(AT) is a major endocrine organ and the primary metabolic energy reservoir.It modulates a variety of processes related to FE such as lipid metabolism and glucose homeostasis and thus measures of inter-animal variation in adiposity are frequently included in the calculation of the RFI index.The aim of this study was to determine the effect of phenotypic RFI status and gender on the expression of key candidate genes related to processes involved in energy metabolism within AT.Dry matter intake(DMI) and average daily gain(ADG) were measured over a period of 70 d for 52 purebred Simmental heifers(n = 24) and bulls(n = 28) with an initial BW±SD of 372±39.6 kg and 387±50.6 kg,respectively.Residual feed intake was calculated and animals were ranked within gender by RFI into high(inefficient; n = 9 heifers and n = 8 bulls)and low(efficient; n = 9 heifers and n = 8 bulls) groups.Results: Average daily gain ±SD and daily DMI ±SD for heifers and bul s were 1.2±0.4 kg and 9.1±0.5 kg,and 1.8±0.3 kg and 9.5±1 kg respectively.High RFI heifers and bulls consumed 10% and 15% more(P < 0.05) than their low RFI counterparts,respectively.Heifers had a higher expression of all genes measured than bulls(P < 0.05).A gender × RFI interaction was detected for HMGCS2(P < 0.05) in which high RFI bulls tended to have lower expression of HMGCS2 than low RFI bulls(P < 0.1),whereas high RFI heifers had higher expression than low RFI heifers(P < 0.05) and high RFI bulls(P < 0.05).SLC2 A4 expression was consistently higher in subcutaneous AT of low RFI animals across gender.Conclusion: The findings of this study indicate that low RFI cattle exhibit upregulation of the molecular mechanisms governing glucose metabolism in adipose tissue,in particular,glucose clearance.The decreased expression of SLC2 A4 in the inefficient cattle may result in less efficient glucose metabolism in these animals.We conclude that SLC2 A4 may be a potential biomarker for RFI in cattle.
文摘Antimicrobial delivery has been advocated for guided tissue regeneration (GTR) or guided bone regeneration (GBR) therapies involving patients with aggressive or unresolved periodontitis/peri-implantitis. Electrospun chitosan membranes demonstrate several advantages over traditional GTR barrier membranes because they stimulate healing, mimic the topology of the extracellular matrix, and allow for diffusion of nutrients and wastes into/out of the graft site, and were shown to stimulate bone formation in a rabbit calvarial criticalsize defect model. Previously, we have shown improvements in mechanical properties and degradation kinetics by crosslinking electrospun membranes with 5 mM or 10 mM genipin. We have also demonstrated the ability of elecrospun chitosan membranes to inhibit lippopolysaccharide (LPS)-induced monocyte activation. In this study, minocycline was incorporated into the chitosan membrane by passive absorption at 5 or 10 mg/mL. The minocycline-loaded membranes and control membranes (carrier only) were tested against Porphyromonas gingivalis (P. gingivalis) by repeated zone of inhibition (ZOI) measurements. Testing showed that uncrosslinked and genipin-crosslinked membranes have similar capacity to absorb aqueous solutions (swelling ratio 1.7 - 2.2). Minocycline loading resulted in bacterial inhibition for up to 8 days from crosslinked membranes (with 11 mm initial ZOI) whereas uncrosslinked membranes loaded with minocycline only inhibited bacteria for 4 days (with 8 mm initial ZOI). These in vitro results suggest that genipin-crosslinked electrospun chitosan membranes loaded with minocycline may be able to reduce early bacterial contamination of GTR graft sites.
基金provided under the National Development Plan,through the Research Stimulus Fund,administered by the Department of Agriculture,Fisheries & Food,Ireland RSF05 224
文摘Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency.The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） diet.Ruminal fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary periods.Quantitative real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes.Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet digestibility.Results：Abundance of methanogens,did not differ between RFI phenotypes.However,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF diet.Conclusions：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.
基金the World Climate Recruitment Programme’s (WCRP) Working Group on Coupled Modelling (WGCM)the Global Organization for Earth System Science Portals (GO-ESSP)+2 种基金jointly supported by the National Science Foundation of China (Grant Nos. 41991231, 91937302)the China 111 project (Grant No. B13045)supported by Supercomputing Center of Lanzhou University
文摘The measurement of atmospheric O_(2)concentrations and related oxygen budget have been used to estimate terrestrial and oceanic carbon uptake.However,a discrepancy remains in assessments of O_(2)exchange between ocean and atmosphere(i.e.air-sea O_(2)flux),which is one of the major contributors to uncertainties in the O_(2)-based estimations of the carbon uptake.Here,we explore the variability of air-sea O_(2)flux with the use of outputs from Coupled Model Intercomparison Project phase 6(CMIP6).The simulated air-sea O_(2)flux exhibits an obvious warming-induced upward trend(~1.49 Tmol yr−2)since the mid-1980s,accompanied by a strong decadal variability dominated by oceanic climate modes.We subsequently revise the O_(2)-based carbon uptakes in response to this changing air-sea O_(2)flux.Our results show that,for the 1990−2000 period,the averaged net ocean and land sinks are 2.10±0.43 and 1.14±0.52 GtC yr−1 respectively,overall consistent with estimates derived by the Global Carbon Project(GCP).An enhanced carbon uptake is found in both land and ocean after year 2000,reflecting the modification of carbon cycle under human activities.Results derived from CMIP5 simulations also investigated in the study allow for comparisons from which we can see the vital importance of oxygen dataset on carbon uptake estimations.
基金funded by Department of Agriculture,Fisheries&Food,Ireland,under the National Development Plan,through the Research Stimulus Fundthe contribution of Science Foundation Ireland(SFI)[grant number:14/IA/2548]to this work.
文摘Background:Previous research in both calves and other species has suggested n-3 polyunsaturated fatty acids(PUFA)andβ-glucans may have positive effects on immune function.This experiment measured performance,behaviour,metabolite and immunological responses to pre-weaning supplementation of dairy bull calves with n-3 PUFA in the form of fish oil andβ-glucans derived from seaweed extract.44 Holstein Friesian bull calves,aged 13.7±2.5 d and weighing 48.0±5.8 kg were artificially reared using an electronic feeding system.Each calf was offered5 L(120 g/L)per day of milk replacer(MR)and assigned to one of four treatments included in the MR,(1)Control(CON);(2)40 g n-3 PUFA per day(FO);(3)1 gβ-glucans per day(GL)and(4)40 g n-3 PUFA per day&1 g/dβ-glucans(FOGL)in a 2×2 factorial design.Milk replacer and concentrate was offered from d 0–62(pre-weaning),while concentrate provision continued for a further 31 d post-weaning period.Individual daily feed intake and feeding behaviour was recorded throughout,while bodyweight and blood analyte data were collected at regular intervals.Results:Overall mean concentrate DMI from d 0–93 was 1.39,1.27,1.00 and 0.72 kg/d for CON,FO,GL and FOGL calves,respectively(SEM=0.037;P<0.0001).Calves supplemented with GL were significantly lighter(P<0.0001)at both weaning(d 62)and turnout to pasture(d 93)than un-supplemented calves,with a similar effect(P<0.0001)evident for calves receiving FO compared to un-supplemented contemporaries.Supplementation with GL reduced the number of unrewarded visits where milk was not consumed(P<0.0001)while supplementation with FO increased mean drinking speed(P<0.0001).Supplementation with GL resulted in greater concentrations of haptoglobin(P=0.034),greater serum osmolality(P=0.021)and lower lymphocyte levels(P=0.027).In addition,cells from GL supplemented calves exhibited a lower response than un-supplemented contemporaries to both Phytohaemagglutinin A stimulated IFN-γ(P=0.019)and Concanavalin A stimulated IFN-γ(P=0.012)following in vitro challenges.Conclusions:Pre-weaning supplementation of bull calves with either n-3 PUFA orβ-glucan resulted in reduced voluntary feed intake of concentrate and consequently poorer pre-weaning calf performance.There was no evidence for any beneficial effect of either supplementation strategy on calves’immune responses.
文摘The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter（OM）.Sampling of the liquid layer for 14 days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4 hr,and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336 hr. Sorption to soil was the major fate for ractopamine in soil：water systems, i.e., 42%–51% of the dose at14 days. The major portion of the sorbed fraction was comprised of non-extractables; a smaller fraction of the sorbed dose was extracted into water and acetone, portions which would be potentially mobile in the environment. Partitioning coefficients for all soils suggested strong sorption of ractopamine to soil which is governed by hydrophobic interactions and cation exchange complexes within the soil OM. Ractopamine degradation was observed, but to mostly non-polar compounds which had a higher potential than ractopamine to sorb to soil. The formation of volatiles was also suggested. Therefore, despite rapid and extensive soil sorption,these studies indicated a portion of ractopamine, present in manures used to fertilize soils,may be mobile in the environment via water-borne events.
文摘Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was conducted with alfalfa（Medicago sativa） and wheat（Triticum aestivum） grown in two soils having different concentrations of organic matter（1.3% and 2.1%）, amended with 0, 0.5, and 10 μg/g of ractopamine. Plant growth ranged from 2.7 to 8.8 g dry weight（dw） for alfalfa, and 8.7 to 40 g dw for wheat and was generally greater in the higher organic matter content soil. The uptake of ractopamine in plant tissues ranged from non-detectable to 897 ng/g and was strongly dependent on soil ractopamine concentration across soil and plant tissue. When adjusted to the total fortified quantities, the amount of ractopamine taken up by the plant tissue was low, 〈 0.01% for either soil.
文摘Chitosan nanofiber membranes have been known to have a high degree of biocompatibility and support new bone formation with controllable biodegradation. The surface area of these membranes may allow them to serve as local delivery carriers for different biologic mediators. Simvastatin, a drug commonly used for lowering cholesterol, has demonstrated promising bone regenerative capability. The aim of this study was to evaluate simvastatin loaded chitosan nanofiber membranes for guided bone regeneration (GBR) applications and their ability to enhance bone formation in rat calvarial defects. Nanofibrous chitosan membranes with random fiber orientation were fabricated by electrospinning technique and loaded with 0.25 mg of simvastatin under sterile conditions. One membrane was implanted subperiosteally to cover an 8 mm diameter critical size calvarial defect. Two groups: 1) Control: non-loaded chitosan membranes;2) Experimental: chitosan membranes loaded with 0.25 mg of simvastatin were evaluated histologically and via micro-computed tomography (micro-CT) for bone formation at 4 and 8 weeks time points (n = 5/group per time point). Both groups exhibited good biocompatibility with only mild or moderate inflammatory response during the healing process. Histologic and micro-CT evaluations confirmed bone formation in calvarial defects as early as 4 weeks using control and experimental membranes. In addition, newly-formed bony bridges consolidating calvarial defects histologically along with partial radiographic defect coverage were observed at 8 weeks in both groups. Although control and experimental groups demonstrated no significant statistical differences in results of bone formation, biodegradable chitosan nanofiber membranes loaded with simvastatin showed a promising regenerative potential as a barrier material for guided bone regeneration applications.
基金supported by the USDA-ARS Research Project#6054-21000-017-0ODCotton Incorporated-sponsored project#19-858
文摘Background:Cotton fiber maturity is an important property that partially determines the processing and performance of cotton.Due to difficulties of obtaining fiber maturity values accurately from every plant of a genetic population,cotton geneticists often use micronaire(MIC) and/or lint percentage for classifying immature phenotypes from mature fiber phenotyp es although they are complex fiber traits.The recent development of an algorithm for determining cotton fiber maturity(MIR)from Fourier transform infrared(FT-IR)spectra explores a novel way to measure fiber maturity efficiently and accurately.However,the algorithm has not been tested with a genetic population consisting of a large number of progeny pla,nts.Results:The merits and limits of the MIC-or lint percentage-bas ed phenotyping method were demonstrated by comparing the observed phenotypes with the predicted phenotypes based on their DNA marker genotypes in a genetic population consisting of 708 F2 plants with various fiber maturity.The observed MIC-based fiber phenotypes matched to the predicted phenotypes better than the observed lint percenta ge-based fiber phenotypes.The lint percentage was obtained from each of F2 plants,whereas the MIC values were unable to be obtained from the entire population since certain F2 plants produced insufficient fiber mass for their measurements.To test the feasibiility of cotton fiber infrared maturity(MIR)as a viable phenotyping tool for genetic analyses,we me asured FT-IR spectra from the second population composed of 80 F2 plants with various fiber maturities,determined MIR values using the algorithms,and compared them with their genotypes in addition to other fiber phenotypes.The results showed that MIR values were successfully obtained from each of the F2 plants,and the observed MIR-based phenotypes fit well to the predicted phenotypes based on their DNA marker genotypes as well as the observed phenotypes based on a combination of MIC and lint percentage.Conclusions:The M,R value obtained from FT-IR spectra of cotton fibers is able to accurately assess fiber maturity of all plants of a population in a quantitative way.The technique provides an option for cotton geneticists to determine fiber maturity rapidly and efficiently.
基金funded through Science Foundation Ireland(SFI)contract no 09/RFP/GEN2447
文摘Background： The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls（mean liveweight 370 ± 35 kg;mean age 479 ± 15 d） were assigned to one of two groups：（i） restricted feed allowance（RES; n = 30） for 125 d（Period 1） followed by ad libitum access to feed for 55 d（Period 2） or（ii） ad libitum access to feed throughout（ADLIB; n = 30）. Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography.Results： Diet × period interactions were evident for genes involved in ketogenesis（BDH2, P = 0.017）, pyruvate metabolism（LDHa, P = 0.048; PDHA1, P = 0.015） and cellular transport and structure（DSG1, P = 0.019; CACT, P = 0.027）. Ruminal concentrations of propionic acid（P = 0.018） and n-valeric acid（P = 0.029） were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency（P = 0.064）toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1.Conclusions： These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.
文摘The influence of chitosaccharides on the symbiotic interaction between Bradyrhizobium and soybean was examined. The results show that chitosaccharides either positively or negatively affect soybean nodulation or plant growth depending on their molecular weight, concentration and the application methods. When directly added to the in vitro culture media, chitosan of high molecular weight inhibit Bradyrhizobium viability in a dose dependent manner while chitooligosaccharides reduce slightly the bacteria viability only at concentration equal or higher than 50 mg·L<sup>-1</sup>. Chitooligosaccharides significantly enhance nodule formation and dry mass in soybean roots at doses between 10 and 100 mg·L<sup>-1</sup>. Both types of chitosaccharides, at the highest doses (>500 mg·L<sup>-1</sup>), negatively affect plant height and root size, whereas medium doses (50 to 100 mg·L<sup>-1</sup>) increase slightly leave number. Under field conditions, foliar application of both chitosaccharides enhances growth and nodulation of soybean plants. Nevertheless, using this application method, chitosan remains more effective than chitooligosaccharides.
基金This study was supported by a grant from the National Natural Science Foundation of China(No. 39260033)and a grant from Guangxi Science Foundation, China (No. 0143058).
文摘OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups: group A, infected with HBV and fed with AFB_1; group B, only infected with HBV; group C, fed with AFB_1 alone; and group D normal control. The tree shrews underwent liver biopsy every. 15 weeks. Liver and tumor tissues were detected by immunohistochemistry and molecular biotechnologies. RESULTS: The incidence of hepatocellular carcinoma (HCC) was higher in group A (66.7%) than in groups B (0) and C (30%). HCC occurrence was earlier in group A than in group C (120.0±16.6 wk vs 153.3±5.8 wk, t=3.336, P<0.01). Mutated p53 protein was not found in all groups before 75 weeks of experiment. At the 105th week, the expression rates of mutated p53 protein were 78.6%, 60.0% and 71.4% in groups A, B and C respectively, which were significantly higher than that in group D (10%) (X^2≥5.03, P<0.05). An abnormal band of the p53 gene was detected in groups A and C. The mutational points of the p53 gene in liver cancer of tree shrews were at codon 275, 78 and 13. Nucleotide sequence and amino acids sequence of tree shrew's wild-type p53 were 91.7% and 93.4% in homology, compared with those of human p53, respectively. CONCLUSIONS: Remarkable synergistic effect on HCC exists between HBV and AFB_1. Mutated p53 protein expressed before occurrence of HCC promotes the development of HCC. HBV and AFB_1 may synergistically induce p53 gene mutation.
基金funded by Teagasc as part of the Irish National Development Plan
文摘Background： Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This study examined gene transcript abundance of important classes of nutrient transporters in the duodenum of non lactating dairy cows of different feed efficiency potential, namely Holstein-Friesian （HF）, Jersey （JE） and their F1 hybrid. Duodenal epithelial tissue was collected at slaughter and stored at -80℃. Total RNA was extracted from tissue and reverse transcribed to generate cDNA. Gene expression of the following transporters, namely nucleoside amino acid; sugar; mineral; and lipid transporters was measured using quantitative real-time RT-PCR. Data were statistically analysed using mixed models ANOVA in SAS. Orthogonal contrasts were used to test for potential heterotic effects and spearman correlation coefficients calculated to determine potential associations amongst gen, expression values and production efficiency variables. Results： While there were no direct effects of genotype on expression values for any of the genes examined, there was evidence for a heterotic effect （P 〈 0.05） on ABCGS, in the form of increased expression in the F1 genotype compared to either of the two parent breeds. Additionally, a tendency for increased expression of the amino acid transporters, SLC3A1 （P= 0.072）, SLC3A2 （P= 0.081） and SLC6A 14 （P= 0.072） was also evident in the F1 genotype. A negative （P 〈 0.05） association was identified between the expression of the glucose transporter gene SLCSA1 and total lactational milk solids yield, corrected for body weight. Positive correlations （P 〈 0.05） were also observed between the expression values of genes involved in common transporter roles. Conclusion： This study suggests that differences in the expression of sterol and amino acid transporters in the duodenum could contribute towards the documented differences in feed efficiency between HF, JE and their F1 hybrid. Furthermore, positive associations between the expression of genes involved in common transporter roles suggest that these may be co-regulated. The study identifies potential candidates for investigation of genetic variants regulating nutrient transport and absorption in the duodenum in dairy cows, which may be incorporated into future breeding programmes.
基金This research was funded by the USDA-Agricultural Research Service CRIS projects 6054-21000-018-00D,and Cotton Incorporated project#19-916.
文摘Previously we identified a major cotton fiber strength QTL(qFS-c7-1)on chromosome A07 using a multiparent advanced generation intercross(MAGIC)population.To assess the stability and transferability of this QTL and its utility in cotton breeding,we made ten new populations.These populations were developed from crosses between MAGIC recombinant inbred lines,or between cotton cultivars that are different from the MAGIC parents.A total of 2801 F_(2) plants were grown and their fiber quality traits were measured.We also selected a subset of F_(3) seeds from two populations,and grew F_(3) progeny plots to further evaluate the stability of this QTL.Our results showed that the peak of qFS-c7-1 is at 70–72 Mb region.This QTL had a major effect on fiber strength explaining 21.9%phenotypic variance.Its effect on other fiber quality attributes such as micronaire,short fiber content,length and uniformity varied between populations,and no effect on fiber elongation was observed.The QTL effects were stable in the populations analyzed,and in different generations of the same population.The SSR and SNP markers near and within the QTL peak reported herein will assist selecting superior fiber quality traits in breeding,with a recommendation that the parental cotton lines should be analyzed using the seven DNA markers within the QTL peak before fully implementing marker assisted selection in a cotton breeding program.
