Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anth...Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anthropogenic sources. The aim of this study was to assess the levels of selenium in the sediments of the Aby Lagoon and its tributaries, the Tanoe River and the Tendo Lagoon, and to examine the spatial and seasonal variations of selenium concentrations. Sediment samples were collected from different sites and seasons, and selenium concentrations were measured by atomic fluorescence spectrometry. The results showed that the average concentration of selenium in the sediments of the Aby Lagoon was 0.82 mg/kg, indicating moderate contamination. The concentration of selenium varied between sites and seasons, with higher values in the channel of the Tendo Lagoon and during the dry season. The study highlighted the complexity of selenium dynamics in aquatic ecosystems, and the need to take into account seasonal and spatial variability as well as interactions between environmental factors. The study also suggested potential ecotoxicological risks for some sensitive organisms in certain areas of the lagoon. This study contributes to the knowledge of the dynamics of selenium in lagoon ecosystems and to the assessment of the environmental risks associated with its presence.展开更多
Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid cha...Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).展开更多
Seed viability is an essential feature for genetic resource conservation as well as sustainable crop production.Long-term storage induces seed viability deterioration or seed aging,accompanied by the accumulation of t...Seed viability is an essential feature for genetic resource conservation as well as sustainable crop production.Long-term storage induces seed viability deterioration or seed aging,accompanied by the accumulation of toxic reactive oxygen species(ROS)to suppress seed germination.Controlled deterioration treatment(CDT)is a gen-eral approach for mimicking seed aging.The transcription factor ANAC089 was previously reported to modulate seed primary germination.In this study,we evaluated the ability of ANAC089 to control seed viability during aging.Compared with that in the wild-type line,the mutation of ANAC089 significantly increased H_(2)O_(2),thereby reducing seed viability after CDT,while the overexpression of ANAC089 reduced H_(2)O_(2) and improved seed long-evity,indicating a critical role for ANAC089 in maintaining seed viability through H_(2)O_(2) signaling.A series of stu-dies have shown that ANAC089 targets and negatively regulates the level of ABI5,an important transmitter of abscisic acid(ABA)signals,to affect seed viability after CDT.Furthermore,ABI5 negatively regulated the expres-sion of VTC2,which is involved in the biosynthesis of the antioxidant ascorbic acid and H_(2)O_(2) scavenging.As a result,ANAC089 attenuates the generation of H_(2)O_(2),thereby enhancing seed viability through the ABI5-VTC2 module during the seed aging process.Taken together,our results reveal a novel mechanism by which ANAC089 enhances seed viability by coordinating ABI5 and VTC2 expression,ultimately preventing the overac-cumulation of H_(2)O_(2),which would have led to reduced seed viability.展开更多
Silver fir(Abies alba Mill.)is a flexible European tree species,mainly vegetating within the mountainous regions of Europe,but its growth responses across its latitudinal and longitudinal range have not yet been satis...Silver fir(Abies alba Mill.)is a flexible European tree species,mainly vegetating within the mountainous regions of Europe,but its growth responses across its latitudinal and longitudinal range have not yet been satisfactorily verified under changing environmental conditions.This study describes the tree-ring increment of silver fir in research plots across a latitudinal gradient from the northern range in Czechia(CZ),through Croatia(HR)to the southernmost range in Italy(IT).The research aims to analyze in detail the dynamics and cyclicity of the ringwidth index(RWI)and how it relates to climatic factors(temperature and precipitation),the North Atlantic Oscillation(NAO),and total solar irradiance(TSI),including the determination of latitude.The results show that the main drivers affecting fir growth are the seasonal NAO index and TSI.Monthly temperatures affect RWI early in the vegetation season,while lack of precipitation during the summer is a limiting factor for fir growth,especially in July.Seasonal temperatures and temperatures in June and July negatively impact,while seasonal precipitation totals in the same months positively influence the RWI in all research plots across meridian.The longest growth cycles in fir RWI were recorded in the northernmost studied plots in CZ.These cyclical fluctuations recede approaching the south.The cyclic increase in RWI is related to the TSI,which decreases its effect from north to south.The TSI's effects vary,positively impacting CZ but negatively influencing HR while remaining relatively neutral in IT.On the other hand,seasonal NAO tends to negatively affect silver fir growth in HR and CZ but has a mildly positive effect in IT.In conclusion,the TSI and the influence of the seasonal NAO index are prevalent in the fir RWI and are accompanied by a greater cyclicity of RWI in Central Europe(temperature optimum)than in the Italian Mediterranean region,where this tree species is limited by climatic conditions,especially lack of precipitation.展开更多
Balsam fir is an important Christmas tree species, especially in eastern Canada. The natural Christmas tree industry faces a challenge in postharvest needle abscission. Though there have been many studies describing t...Balsam fir is an important Christmas tree species, especially in eastern Canada. The natural Christmas tree industry faces a challenge in postharvest needle abscission. Though there have been many studies describing the physiological triggers and consequences in postharvest balsam fir, there have been no studies describing morphological or ultrastructural changes. Therefore, the objective of this study was to examine changes in stomata and chloroplast of postharvest needles. Branches were collected from low and high needle abscission resistance balsam fir genotypes, placed in water, and displayed in typical household conditions for 11 weeks. Needle abscission, chlorophyll fluorescence, and water uptake were monitored throughout. Needles stomata and chloroplasts were examined under a scanning and transmission electron microscope, respectively, each week. All branches had increased abscission, decreased chlorophyll fluorescence, and decreased water uptake over time. Needle surfaces accumulated fungal hyphae, especially in stomata. Chloroplasts demonstrated some dysfunction within two weeks, with notable decreases in chloroplast starch and increases in plastoglobulins. Within several weeks thylakoid membranes had been dismantled as chloroplasts transformed into gerontoplasts. All biophysical and structural changes were more pronounced in low needle abscission resistant genotypes. This research identifies a potential role for needle fungi in postharvest needle abscission and confirms the postharvest senescence of chloroplasts. Though it was previously speculated that chloroplasts must senesce postharvest, this study identifies how quickly this process occurs and that it occurs at different rates in contrasting genotypes.展开更多
Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and...Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and is associated with an increased risk of coronary heart disease, stroke, and leg amputation. The first-line method for diagnosis of PAD is the Ankle Brachial Index (ABI), which is the ratio of ankle to brachial higher systolic pressure measured in ankles and arms. The Toe Brachial Index (TBI), which is the ratio of the toe systolic pressure to brachial higher systolic pressure measured in both arms, is considered to be an alternative to the ABI in screening for PAD. The ABI and TBI are measured on the right and left side, and the lower of these numbers is the patient’s overall ABI and TBI. Clinical studies and meta-analysis reviews have shown that the conventional ABI measurement, which uses a cuff, and handheld sphygmomanometer and continuous-wave Doppler tracings, provides an acceptable-to-high specificity level but low sensitivity when compared with vascular color Doppler ultrasound, and/or angiography methods. Another study has shown that the TBI measurement has greater sensitivity but lower specificity than the ABI when compared with vascular color Doppler ultrasound diagnostic based on waveforms. The aim of this clinical study was to evaluate the specificity and sensitivity of the VasoPad System comparing its results to the vascular color doppler ultrasound waveforms. Materials and Methods: The VasoPad System is an automated device using the pulse wave method to measure the arms and ankles dorsalis and tibial posterior artery blood pressures, the photoplethysmography second derivative (PTGSD) to estimate the toe systolic pressure, a patented photoplethysmography (PTG) index marker and volume plethysmography via cuffs during deflation. Vascular Color Doppler ultrasound can diagnose stenosis through the direct visualization of atherosclerosis or plaques and through waveform analysis. The vascular color Doppler ultrasound provides 3 waveform types. The type 1, triphasic waveform is normal blood flow and no atherosclerosis or plaque, the type 2, diphasic waveform is seen when there are atherosclerosis plaques, but normal blood flow, and the type 3, monophasic waveform reflects stenosis with diameter reduction > 50%. Results: The sum of the overall ABI and TBI VasoPad values, called Sum of Brachial Indices (SBI), gave a specificity of 88.89% and sensitivity of 100% for detecting vascular color Doppler ultrasound biphasic and monophasic waveforms versus triphasic waveforms with a cutoff ≤ 1.36 (P Conclusion: The VasoPad was useful for detecting PAD, which is fully defined as having vessel stenosis > 50% (Doppler monophasic waveforms) but also early stage of atherosclerosis plaque of the lower extremities (Doppler biphasic waveforms). The VasoPad method provided a remarkable sensitivity of 100% and a specificity level similar to those of the conventional ABI test method compared with the vascular color Doppler ultrasound. In addition to being useful to screen and detect PAD, the VasoPad offers early detection of lower extremity atherosclerosis, with normal blood flow (Doppler biphasic waveforms), which could provide greater treatment options and thus reduce the overall number of lower extremity complications.展开更多
文摘Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anthropogenic sources. The aim of this study was to assess the levels of selenium in the sediments of the Aby Lagoon and its tributaries, the Tanoe River and the Tendo Lagoon, and to examine the spatial and seasonal variations of selenium concentrations. Sediment samples were collected from different sites and seasons, and selenium concentrations were measured by atomic fluorescence spectrometry. The results showed that the average concentration of selenium in the sediments of the Aby Lagoon was 0.82 mg/kg, indicating moderate contamination. The concentration of selenium varied between sites and seasons, with higher values in the channel of the Tendo Lagoon and during the dry season. The study highlighted the complexity of selenium dynamics in aquatic ecosystems, and the need to take into account seasonal and spatial variability as well as interactions between environmental factors. The study also suggested potential ecotoxicological risks for some sensitive organisms in certain areas of the lagoon. This study contributes to the knowledge of the dynamics of selenium in lagoon ecosystems and to the assessment of the environmental risks associated with its presence.
文摘Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).
基金supported by the National Natural Science Foundation of China(31970289 to X.H.and 32170562 to P.L.).
文摘Seed viability is an essential feature for genetic resource conservation as well as sustainable crop production.Long-term storage induces seed viability deterioration or seed aging,accompanied by the accumulation of toxic reactive oxygen species(ROS)to suppress seed germination.Controlled deterioration treatment(CDT)is a gen-eral approach for mimicking seed aging.The transcription factor ANAC089 was previously reported to modulate seed primary germination.In this study,we evaluated the ability of ANAC089 to control seed viability during aging.Compared with that in the wild-type line,the mutation of ANAC089 significantly increased H_(2)O_(2),thereby reducing seed viability after CDT,while the overexpression of ANAC089 reduced H_(2)O_(2) and improved seed long-evity,indicating a critical role for ANAC089 in maintaining seed viability through H_(2)O_(2) signaling.A series of stu-dies have shown that ANAC089 targets and negatively regulates the level of ABI5,an important transmitter of abscisic acid(ABA)signals,to affect seed viability after CDT.Furthermore,ABI5 negatively regulated the expres-sion of VTC2,which is involved in the biosynthesis of the antioxidant ascorbic acid and H_(2)O_(2) scavenging.As a result,ANAC089 attenuates the generation of H_(2)O_(2),thereby enhancing seed viability through the ABI5-VTC2 module during the seed aging process.Taken together,our results reveal a novel mechanism by which ANAC089 enhances seed viability by coordinating ABI5 and VTC2 expression,ultimately preventing the overac-cumulation of H_(2)O_(2),which would have led to reduced seed viability.
文摘密码子偏性是影响外源基因表达的重要因素,也是反映基因家族进化的关键线索之一。兰科植物是植物保护中的“旗舰”类群,且多数物种具有药用和观赏价值,但种子不易萌发,而ABI3(abscisic acid insensitive 3)基因是ABA信号转导的中心调控因子,是调控植物种子萌发的关键因子。因此,深入研究兰科ABI3基因密码子偏性,可为解析该基因功能、优化密码子组成奠定基础。本研究以拟南芥ABI3基因为探针,从公共数据库(NCBI)筛选出45条兰科植物ABI3基因,通过CodonW、SPSS、MEGA等生物信息学程序对其进行密码子使用模式和偏好性分析。相关参数分析结果表明,该基因的ENC(effective number of codon)值范围分布为40.84~58.46,其中大于52的占82.2%,CAI(codon adaptation index)平均值为0.203,远小于1,表明ABI3基因的密码子偏性相对较弱;中性绘图分析显示,GC12与GC3的回归曲线的斜率为0.6103,R2=0.7928,P<0.05,有极高的相关性,这暗示着碱基组成对密码子偏性具有重要的影响;ENC-plot分析中,所有基因ENC值都低于期望值,但相差不大,说明兰科ABI3基因密码子主要受碱基突变的影响,同时也受选择压力等其他因素影响。奇偶偏好性分析显示,大多数基因分布在平面图的右侧区域,密码子第3位A/T(U)的使用频率高于G/C。通过RSCU和ΔRSCU分析确定了26个最优密码子,其中以A/T(U)结尾的密码子有14个,以T(U)结尾的密码子有10个,说明兰科植物ABI3基因相对偏好使用A/U结尾的密码子,尤其偏好使用T(U)结尾的密码子,这与大多数单子叶植物密码子使用偏好不同。本研究可为兰科植物ABI3基因的系统发育、功能解析、提高ABI3基因表达效率提供理论基础,同时可为促进植物密码子生物学研究及外源基因改良提供参考。
基金supported by the Czech University of Life Sciences Prague,Faculty of Forestry and Wood Sciences(No.IGA A_21_26)the Ministry of Agriculture of the Czech Republic(No.QK1910292 and QK21020371).
文摘Silver fir(Abies alba Mill.)is a flexible European tree species,mainly vegetating within the mountainous regions of Europe,but its growth responses across its latitudinal and longitudinal range have not yet been satisfactorily verified under changing environmental conditions.This study describes the tree-ring increment of silver fir in research plots across a latitudinal gradient from the northern range in Czechia(CZ),through Croatia(HR)to the southernmost range in Italy(IT).The research aims to analyze in detail the dynamics and cyclicity of the ringwidth index(RWI)and how it relates to climatic factors(temperature and precipitation),the North Atlantic Oscillation(NAO),and total solar irradiance(TSI),including the determination of latitude.The results show that the main drivers affecting fir growth are the seasonal NAO index and TSI.Monthly temperatures affect RWI early in the vegetation season,while lack of precipitation during the summer is a limiting factor for fir growth,especially in July.Seasonal temperatures and temperatures in June and July negatively impact,while seasonal precipitation totals in the same months positively influence the RWI in all research plots across meridian.The longest growth cycles in fir RWI were recorded in the northernmost studied plots in CZ.These cyclical fluctuations recede approaching the south.The cyclic increase in RWI is related to the TSI,which decreases its effect from north to south.The TSI's effects vary,positively impacting CZ but negatively influencing HR while remaining relatively neutral in IT.On the other hand,seasonal NAO tends to negatively affect silver fir growth in HR and CZ but has a mildly positive effect in IT.In conclusion,the TSI and the influence of the seasonal NAO index are prevalent in the fir RWI and are accompanied by a greater cyclicity of RWI in Central Europe(temperature optimum)than in the Italian Mediterranean region,where this tree species is limited by climatic conditions,especially lack of precipitation.
文摘Balsam fir is an important Christmas tree species, especially in eastern Canada. The natural Christmas tree industry faces a challenge in postharvest needle abscission. Though there have been many studies describing the physiological triggers and consequences in postharvest balsam fir, there have been no studies describing morphological or ultrastructural changes. Therefore, the objective of this study was to examine changes in stomata and chloroplast of postharvest needles. Branches were collected from low and high needle abscission resistance balsam fir genotypes, placed in water, and displayed in typical household conditions for 11 weeks. Needle abscission, chlorophyll fluorescence, and water uptake were monitored throughout. Needles stomata and chloroplasts were examined under a scanning and transmission electron microscope, respectively, each week. All branches had increased abscission, decreased chlorophyll fluorescence, and decreased water uptake over time. Needle surfaces accumulated fungal hyphae, especially in stomata. Chloroplasts demonstrated some dysfunction within two weeks, with notable decreases in chloroplast starch and increases in plastoglobulins. Within several weeks thylakoid membranes had been dismantled as chloroplasts transformed into gerontoplasts. All biophysical and structural changes were more pronounced in low needle abscission resistant genotypes. This research identifies a potential role for needle fungi in postharvest needle abscission and confirms the postharvest senescence of chloroplasts. Though it was previously speculated that chloroplasts must senesce postharvest, this study identifies how quickly this process occurs and that it occurs at different rates in contrasting genotypes.
文摘Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and is associated with an increased risk of coronary heart disease, stroke, and leg amputation. The first-line method for diagnosis of PAD is the Ankle Brachial Index (ABI), which is the ratio of ankle to brachial higher systolic pressure measured in ankles and arms. The Toe Brachial Index (TBI), which is the ratio of the toe systolic pressure to brachial higher systolic pressure measured in both arms, is considered to be an alternative to the ABI in screening for PAD. The ABI and TBI are measured on the right and left side, and the lower of these numbers is the patient’s overall ABI and TBI. Clinical studies and meta-analysis reviews have shown that the conventional ABI measurement, which uses a cuff, and handheld sphygmomanometer and continuous-wave Doppler tracings, provides an acceptable-to-high specificity level but low sensitivity when compared with vascular color Doppler ultrasound, and/or angiography methods. Another study has shown that the TBI measurement has greater sensitivity but lower specificity than the ABI when compared with vascular color Doppler ultrasound diagnostic based on waveforms. The aim of this clinical study was to evaluate the specificity and sensitivity of the VasoPad System comparing its results to the vascular color doppler ultrasound waveforms. Materials and Methods: The VasoPad System is an automated device using the pulse wave method to measure the arms and ankles dorsalis and tibial posterior artery blood pressures, the photoplethysmography second derivative (PTGSD) to estimate the toe systolic pressure, a patented photoplethysmography (PTG) index marker and volume plethysmography via cuffs during deflation. Vascular Color Doppler ultrasound can diagnose stenosis through the direct visualization of atherosclerosis or plaques and through waveform analysis. The vascular color Doppler ultrasound provides 3 waveform types. The type 1, triphasic waveform is normal blood flow and no atherosclerosis or plaque, the type 2, diphasic waveform is seen when there are atherosclerosis plaques, but normal blood flow, and the type 3, monophasic waveform reflects stenosis with diameter reduction > 50%. Results: The sum of the overall ABI and TBI VasoPad values, called Sum of Brachial Indices (SBI), gave a specificity of 88.89% and sensitivity of 100% for detecting vascular color Doppler ultrasound biphasic and monophasic waveforms versus triphasic waveforms with a cutoff ≤ 1.36 (P Conclusion: The VasoPad was useful for detecting PAD, which is fully defined as having vessel stenosis > 50% (Doppler monophasic waveforms) but also early stage of atherosclerosis plaque of the lower extremities (Doppler biphasic waveforms). The VasoPad method provided a remarkable sensitivity of 100% and a specificity level similar to those of the conventional ABI test method compared with the vascular color Doppler ultrasound. In addition to being useful to screen and detect PAD, the VasoPad offers early detection of lower extremity atherosclerosis, with normal blood flow (Doppler biphasic waveforms), which could provide greater treatment options and thus reduce the overall number of lower extremity complications.
