Xanthine oxidoreductase (XOR) is a molybdoflavoprotein mainly involved in purine catabolism. It exists in two forms, the oxidase (XO) and dehydrogenase (XDH) which are inter-convertible within mammalian cells. Althoug...Xanthine oxidoreductase (XOR) is a molybdoflavoprotein mainly involved in purine catabolism. It exists in two forms, the oxidase (XO) and dehydrogenase (XDH) which are inter-convertible within mammalian cells. Although various researchers have reported the extraction of mammalian XOR, no extractions have yet been carried out in Malta and subsequently no characterizations are available. In this study, XOR was successfully purified from bovine, caprine and ovine milk through a multistep purification process involving both chemical and chromatographic techniques. The molecular weights of the native enzyme were found to be 295 kDa, 281 kDa and 275 kDa, representing the bovine, caprine and ovine XOR respectively. Western blot showed XOR to be represented on SDS-PAGE by a minimum of three major bands having molecular weights of 151 kDa, 131 kDa and 85 kDa. While all samples showed activity on native PAGE, spectrophotometric assays revealed the bovine XOR to be the most active. Surprisingly, the addition of NAD+ to the assay mixture inhibited enzyme activity of the bovine and caprine XOR whereas the ovine XOR doubled its activity in response to NAD+. The latter also showed a lower binding affinity to heparin. Following incubation with trypsin, XOR was irreversibly converted to its oxidase form in all samples as reflected by the observed increase in XO activity.展开更多
Exporting is of great interest for SMEs in Jordan from both microeconomic and macroeconomic perspective.The objective of this study was to identify to what extent specific internal factors contribute to export success...Exporting is of great interest for SMEs in Jordan from both microeconomic and macroeconomic perspective.The objective of this study was to identify to what extent specific internal factors contribute to export success of SMEs in Jordan.This study hypothesized that export performance of SMEs is directly affected by three groups of internal factors.These include firm characteristics,managerial characteristics,and marketing strategy.A multiple case approach is used to conduct this research and a structured interview is developed to collect the data directly from the participants.A pattern matching approach was used to test the hypotheses.The results show that export performance is positively affected by firm characteristics,managerial characteristics,and marketing strategy.Additionally,the demographic characteristics of managers and adaptation of distribution channels are unlikely to have an influence on export performance.This was unexpected,because of the plenty of empirical evidences in the literature that support the impact of these variables on export success.展开更多
For small and medium sized enterprises,portfolio management can be a difficult exercise;especially when the available paths forwards are shrouded in mystery.To overcome this,they are required to research and decide up...For small and medium sized enterprises,portfolio management can be a difficult exercise;especially when the available paths forwards are shrouded in mystery.To overcome this,they are required to research and decide upon the path to follow,but this can be difficult when the information to gather is unclear,leading to ad-hoc processes and inconsistency.The motivation for this project originated from a small and medium sized enterprise experiencing this problem of unknown critical information and a technological portfolio with significant potential.With no procedure or method in place,they conducted the research in an ad-hoc way resulting in uncertainty and low repeatability of decisions.To tackle this problem,innovation structuring frameworks were synthesised with appropriate risks and context to pose a new structure for information capture.The resulting structure was tested within the small and medium sized enterprise to investigate the repeatability of the information capture and the subsequent ranking.The proposed structure was also analysed by-process experts for its wider applicability.For the small and medium sized enterprise,this led to a consistent and repeatable method that delivered increased confidence about selecting a path forwards for its portfolio.In addition,it was found to be applicable to external organisations increasing the moders worth and applicability.The implications of this work have led to a change in the operational procedure of the small and medium sized enterprise to utilise the defined process for researching new ideas for their portfolio which can lead to repeatable and trustworthy decisions.This also has applicability to other similar companies and could lead them through a repeatable process as presented here.展开更多
Conspicuous coloration in animals serves many functions such as anti-predation.Anti-predation strategies include motion dazzle and flash behavior.Motion dazzle markings can reduce the probability of being preyed on be...Conspicuous coloration in animals serves many functions such as anti-predation.Anti-predation strategies include motion dazzle and flash behavior.Motion dazzle markings can reduce the probability of being preyed on because the predators misjudge their movement.In flash behavior,prey demonstrate conspicuous cue while fleeing;the predators follow them;however,the prey hide their markings and the predators assume that the prey has vanished.To investigate whether bovids use conspicuous hindquarter markings as an anti-predatory behavior,we undertook phylogenetically controlled analyses to explore under what physiological characteristics and environmental factors bovids might have this color pattern.The results suggested that rump patches and tail markings were more prevalent in bovids living in larger-sized groups,which supports the hypothesis of intraspecific communication.Moreover,we observed the occurrence of conspicuous white hindquarter markings in bovids having smaller body size and living in larger groups,suggesting a motion dazzle function.However,the feature of facultative exposing color patterns(flash markings)was not associated with body size,which was inconsistent with predictions and implied that bovids may not adopt this as an anti-predator strategy.It was concluded that species in bovids with conspicuous white hindquarter markings adopt motion dazzle as an anti-predation strategy while fleeing and escaping from being prey on.展开更多
文摘Xanthine oxidoreductase (XOR) is a molybdoflavoprotein mainly involved in purine catabolism. It exists in two forms, the oxidase (XO) and dehydrogenase (XDH) which are inter-convertible within mammalian cells. Although various researchers have reported the extraction of mammalian XOR, no extractions have yet been carried out in Malta and subsequently no characterizations are available. In this study, XOR was successfully purified from bovine, caprine and ovine milk through a multistep purification process involving both chemical and chromatographic techniques. The molecular weights of the native enzyme were found to be 295 kDa, 281 kDa and 275 kDa, representing the bovine, caprine and ovine XOR respectively. Western blot showed XOR to be represented on SDS-PAGE by a minimum of three major bands having molecular weights of 151 kDa, 131 kDa and 85 kDa. While all samples showed activity on native PAGE, spectrophotometric assays revealed the bovine XOR to be the most active. Surprisingly, the addition of NAD+ to the assay mixture inhibited enzyme activity of the bovine and caprine XOR whereas the ovine XOR doubled its activity in response to NAD+. The latter also showed a lower binding affinity to heparin. Following incubation with trypsin, XOR was irreversibly converted to its oxidase form in all samples as reflected by the observed increase in XO activity.
文摘Exporting is of great interest for SMEs in Jordan from both microeconomic and macroeconomic perspective.The objective of this study was to identify to what extent specific internal factors contribute to export success of SMEs in Jordan.This study hypothesized that export performance of SMEs is directly affected by three groups of internal factors.These include firm characteristics,managerial characteristics,and marketing strategy.A multiple case approach is used to conduct this research and a structured interview is developed to collect the data directly from the participants.A pattern matching approach was used to test the hypotheses.The results show that export performance is positively affected by firm characteristics,managerial characteristics,and marketing strategy.Additionally,the demographic characteristics of managers and adaptation of distribution channels are unlikely to have an influence on export performance.This was unexpected,because of the plenty of empirical evidences in the literature that support the impact of these variables on export success.
基金This work was supported by EPSRC under Grant No.EP/G037353/1(IDC Systems)and iMETRUM Ltd.
文摘For small and medium sized enterprises,portfolio management can be a difficult exercise;especially when the available paths forwards are shrouded in mystery.To overcome this,they are required to research and decide upon the path to follow,but this can be difficult when the information to gather is unclear,leading to ad-hoc processes and inconsistency.The motivation for this project originated from a small and medium sized enterprise experiencing this problem of unknown critical information and a technological portfolio with significant potential.With no procedure or method in place,they conducted the research in an ad-hoc way resulting in uncertainty and low repeatability of decisions.To tackle this problem,innovation structuring frameworks were synthesised with appropriate risks and context to pose a new structure for information capture.The resulting structure was tested within the small and medium sized enterprise to investigate the repeatability of the information capture and the subsequent ranking.The proposed structure was also analysed by-process experts for its wider applicability.For the small and medium sized enterprise,this led to a consistent and repeatable method that delivered increased confidence about selecting a path forwards for its portfolio.In addition,it was found to be applicable to external organisations increasing the moders worth and applicability.The implications of this work have led to a change in the operational procedure of the small and medium sized enterprise to utilise the defined process for researching new ideas for their portfolio which can lead to repeatable and trustworthy decisions.This also has applicability to other similar companies and could lead them through a repeatable process as presented here.
基金This study received support from the Tibet Major Science and Technology Project(XZ201901-GA-06).
文摘Conspicuous coloration in animals serves many functions such as anti-predation.Anti-predation strategies include motion dazzle and flash behavior.Motion dazzle markings can reduce the probability of being preyed on because the predators misjudge their movement.In flash behavior,prey demonstrate conspicuous cue while fleeing;the predators follow them;however,the prey hide their markings and the predators assume that the prey has vanished.To investigate whether bovids use conspicuous hindquarter markings as an anti-predatory behavior,we undertook phylogenetically controlled analyses to explore under what physiological characteristics and environmental factors bovids might have this color pattern.The results suggested that rump patches and tail markings were more prevalent in bovids living in larger-sized groups,which supports the hypothesis of intraspecific communication.Moreover,we observed the occurrence of conspicuous white hindquarter markings in bovids having smaller body size and living in larger groups,suggesting a motion dazzle function.However,the feature of facultative exposing color patterns(flash markings)was not associated with body size,which was inconsistent with predictions and implied that bovids may not adopt this as an anti-predator strategy.It was concluded that species in bovids with conspicuous white hindquarter markings adopt motion dazzle as an anti-predation strategy while fleeing and escaping from being prey on.
文摘微卫星(simples equencere peats, SSRs)广泛分布于生物基因组中,是最常用的分子标记之一。本研究利用生物信息学方法搜索和统计了7种牛科动物转录组中完整型SSRs序列,揭示不同重复类型SSRs变异水平,并对其生物信息学特征进行比较分析。在牛科动物转录组中,牛、绵羊和山羊SSRs总丰度较高,三者基本一致(157.98, 157.09 vs 158.52个/Mb);其次是瘤牛和水牛(140.70 vs 129.63个/Mb);牦牛微卫星总丰度较低(96.99个/Mb),藏羚羊微卫星总丰度最低(63.71个/Mb)。牛科动物转录组中SSRs所占比例普遍偏低,范围为0.156%~0.753%,三碱基SSRs占主导地位,并且以(CCG)n和(AGG)n为优势重复基元,这可能与转录组编码区三联体密码子高度保守有关。在这7种牛科动物转录组中,相同单碱基至六碱基SSRs重复拷贝数(repeat copy number, RCN)分布高度一致。通过牛科动物转录组SSRs变异系数(coefficient of variability, CV)分析表明,单碱基SSRs和二碱基SSRs重复拷贝数变异水平较高,其次RCN变异模式如下:三碱基SSRs>四碱基SSRs>六碱基SSRs>五碱基SSRs,六碱基SSRs重复拷贝数变异水平有稍微增加的趋势。本研究为牛科动物SSR标记的开发、遗传多样性评估和遗传育种提供科学依据。
