Yukiko Yonemori, Shogo Kokubu, Gregory N. Nishihara, H. Endo, Ryuta Terada
The responses of photochemical efficiency to desiccation and salinity gradients in an intertidal edible brown macroalga, Sargassum fusiforme (Harvey) Setchell (Sargassaceae, Fucales), were determined using a pulse amplitude modulation (PAM)‐chlorophyll fluorometer. The effective quantum yields (ΔF/Fm'; = ΦPSII) of photosystem II (PSII) dropped to zero after 360‐min aerial exposure under low irradiance (20 μmol photons m−2 s−1) and 120‐min exposure under high irradiance (700 μmol photons m−2 s−1) for this species at 20°C and 50% relative humidity. Under these conditions, ΔF/Fm' failed to recover to initial levels even after 1‐day rehydration in seawater. In general, ΔF/Fm' decreased as desiccation reduced the absolute water content (AWC, %). Nevertheless, when AWC was above ca. 20%, ΔF/Fm' was mostly restored to initial levels after 1‐day rehydration in seawater, suggesting strong tolerance to dehydration. Furthermore, S. fusiforme appeared to tolerate a broad range of salinity (i.e. 15–50 psu) during six days of culture; however, ΔF/Fm' declined when salinity was <10 and 60 psu. Strong tolerance to dehydration and salinity stress likely provides S. fusiforme an advantage that allows it to flourish in the intertidal habitat.
{"title":"The effects of desiccation and salinity gradients on the PSII photochemical efficiency of an intertidal brown alga, Sargassum fusiforme from Kagoshima, Japan","authors":"Yukiko Yonemori, Shogo Kokubu, Gregory N. Nishihara, H. Endo, Ryuta Terada","doi":"10.1111/pre.12491","DOIUrl":"https://doi.org/10.1111/pre.12491","url":null,"abstract":"The responses of photochemical efficiency to desiccation and salinity gradients in an intertidal edible brown macroalga, Sargassum fusiforme (Harvey) Setchell (Sargassaceae, Fucales), were determined using a pulse amplitude modulation (PAM)‐chlorophyll fluorometer. The effective quantum yields (ΔF/Fm'; = ΦPSII) of photosystem II (PSII) dropped to zero after 360‐min aerial exposure under low irradiance (20 μmol photons m−2 s−1) and 120‐min exposure under high irradiance (700 μmol photons m−2 s−1) for this species at 20°C and 50% relative humidity. Under these conditions, ΔF/Fm' failed to recover to initial levels even after 1‐day rehydration in seawater. In general, ΔF/Fm' decreased as desiccation reduced the absolute water content (AWC, %). Nevertheless, when AWC was above ca. 20%, ΔF/Fm' was mostly restored to initial levels after 1‐day rehydration in seawater, suggesting strong tolerance to dehydration. Furthermore, S. fusiforme appeared to tolerate a broad range of salinity (i.e. 15–50 psu) during six days of culture; however, ΔF/Fm' declined when salinity was <10 and 60 psu. Strong tolerance to dehydration and salinity stress likely provides S. fusiforme an advantage that allows it to flourish in the intertidal habitat.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44269181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Yamaguchi, Masaki Zaima, Masao Adachi, Y. Tomaru, H. Asahara, N. Nishiwaki
Several diatom species can utilize various forms of organic phosphorus via enzymatic hydrolysis. The present study identified which phosphorus compounds are preferentially utilized by planktonic diatom Chaetoceros tenuissimus cultures using a 31P nuclear magnetic resonance (NMR)‐based method. Our 31P NMR analysis, which involves a sample extraction procedure using DIAION™ CR11, detected and quantified phosphorus compounds present at concentrations of at least 7.5 μM in the seawater‐based media, including orthophosphate, phosphate monoester, phosphate diester, phosphonate, and other compounds. Based on this analysis, we examined the temporal variations of phosphorus compounds in C. tenuissimus cultures in which orthophosphate, phosphate monoester, phosphate diester, and phosphonate compounds were present simultaneously. Cells pre‐grown under phosphorus‐replete conditions utilized orthophosphate as the preferential phosphorus source and switched to phosphate monoester after exhausting orthophosphate. Enzymatic activity for phosphate monoester hydrolysis, namely phosphomonoesterase (synonym to alkaline phosphatase) activity, appeared when C. tenuissimus began to utilize phosphate monoester. In contrast, C. tenuissimus pre‐grown on phosphorus‐depleted media simultaneously hydrolyzed phosphate monoester and phosphate diester compounds, released orthophosphate from these compounds, and utilized the released orthophosphate and original orthophosphate without discrimination. Overall, we demonstrated that 31P NMR‐based method can comprehensively analyze the variations of dissolved phosphorus compounds in diatom cultures. Our results showed selective utilization of phosphorus compounds by C. tenuissimus and suggested that phosphate monoester and phosphate diester compounds were important phosphorus sources for this diatom in orthophosphate‐depleted coastal waters.
{"title":"Selective utilization of phosphorus compounds by Chaetoceros tenuissimus (Bacillariophyceae): Approach using 31P nuclear magnetic resonance analysis","authors":"H. Yamaguchi, Masaki Zaima, Masao Adachi, Y. Tomaru, H. Asahara, N. Nishiwaki","doi":"10.1111/pre.12485","DOIUrl":"https://doi.org/10.1111/pre.12485","url":null,"abstract":"Several diatom species can utilize various forms of organic phosphorus via enzymatic hydrolysis. The present study identified which phosphorus compounds are preferentially utilized by planktonic diatom Chaetoceros tenuissimus cultures using a 31P nuclear magnetic resonance (NMR)‐based method. Our 31P NMR analysis, which involves a sample extraction procedure using DIAION™ CR11, detected and quantified phosphorus compounds present at concentrations of at least 7.5 μM in the seawater‐based media, including orthophosphate, phosphate monoester, phosphate diester, phosphonate, and other compounds. Based on this analysis, we examined the temporal variations of phosphorus compounds in C. tenuissimus cultures in which orthophosphate, phosphate monoester, phosphate diester, and phosphonate compounds were present simultaneously. Cells pre‐grown under phosphorus‐replete conditions utilized orthophosphate as the preferential phosphorus source and switched to phosphate monoester after exhausting orthophosphate. Enzymatic activity for phosphate monoester hydrolysis, namely phosphomonoesterase (synonym to alkaline phosphatase) activity, appeared when C. tenuissimus began to utilize phosphate monoester. In contrast, C. tenuissimus pre‐grown on phosphorus‐depleted media simultaneously hydrolyzed phosphate monoester and phosphate diester compounds, released orthophosphate from these compounds, and utilized the released orthophosphate and original orthophosphate without discrimination. Overall, we demonstrated that 31P NMR‐based method can comprehensively analyze the variations of dissolved phosphorus compounds in diatom cultures. Our results showed selective utilization of phosphorus compounds by C. tenuissimus and suggested that phosphate monoester and phosphate diester compounds were important phosphorus sources for this diatom in orthophosphate‐depleted coastal waters.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47771206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ukraine's private clinics step into the breach of a targeted health system.","authors":"Nataliia Bushkovska","doi":"10.1136/bmj.o1081","DOIUrl":"10.1136/bmj.o1081","url":null,"abstract":"","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":"48 1","pages":"o1081"},"PeriodicalIF":0.0,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79655714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gertia stigmatica is an atypical member of the Kareniaceae that has a peridinin‐containing plastid rather than a tertiary, (acyloxy)fucoxanthin‐containing, haptophyte‐derived plastid, as is found in the canonical genera Karenia, Karlodinium, and Takayama. While the origin of G. stigmatica's plastid is uncertain per its original published description, with alternative hypotheses stating that it could have originated before or after the acquisition of a haptophyte‐derived plastid, the description of the species indicates that it does possess ultrastructural and genetic features that firmly place it within the Kareniaceae. As a photosynthetic, plastid‐containing organism, G. stigmatica, like other algae, possesses two galactolipids, mono‐ and digalactosyldiacylglycerol (MGDG and DGDG, respectively), that form the basis of its plastid‐associated photosynthetic membranes. MGDG and DGDG have been extensively characterized in peridinin‐containing dinoflagellates, where it has been observed that these dinoflagellates can be segregated into two clusters. One cluster is characterized by MGDG and DGDG possessing the polyunsaturated C18/C18 fatty acids (sn‐1/sn‐2 regiochemistry) octadecapentaenoic acid (18:5(n‐3)) and octadecatetraenoic acid (18:4(n‐3)), while the second cluster possesses eicosapentaenoic acid (20:5(n‐3)) in the sn‐1 position while retaining a polyunsaturated C18 fatty acid in the sn‐2 position. By contrast, Karenia brevis and Karenia mikimotoi have been observed to be enriched in species of MGDG and DGDG, such as 18:5(n‐3)/14:0 MGDG and DGDG, uncommon to peridinin‐containing dinoflagellates. Our objective was to characterize the galactolipids of G. stigmatica to compare it to both peridinin‐containing dinoflagellates and other members of the Kareniaceae to search for insight, such as (a) remnant 14:0 fatty acid‐containing galactolipid(s), into the evolution of its plastid. Our results show that G. stigmatica possesses 20:5(n‐3)/18:5(n‐3) MGDG and DGDG as the primary galactolipids, with little evidence of those galactolipid species enriched in K. brevis and K. mikimotoi. The implications of this for the evolution of the G. stigmatica plastid are discussed.
{"title":"Galactolipid composition of Gertia stigmatica (Dinophyceae), an atypical member of the Kareniaceae with a peridinin‐containing, non‐haptophyte‐derived plastid","authors":"Jeffrey D. Leblond, Kyra Sabir, Jori E. Graeff","doi":"10.1111/pre.12488","DOIUrl":"https://doi.org/10.1111/pre.12488","url":null,"abstract":"Gertia stigmatica is an atypical member of the Kareniaceae that has a peridinin‐containing plastid rather than a tertiary, (acyloxy)fucoxanthin‐containing, haptophyte‐derived plastid, as is found in the canonical genera Karenia, Karlodinium, and Takayama. While the origin of G. stigmatica's plastid is uncertain per its original published description, with alternative hypotheses stating that it could have originated before or after the acquisition of a haptophyte‐derived plastid, the description of the species indicates that it does possess ultrastructural and genetic features that firmly place it within the Kareniaceae. As a photosynthetic, plastid‐containing organism, G. stigmatica, like other algae, possesses two galactolipids, mono‐ and digalactosyldiacylglycerol (MGDG and DGDG, respectively), that form the basis of its plastid‐associated photosynthetic membranes. MGDG and DGDG have been extensively characterized in peridinin‐containing dinoflagellates, where it has been observed that these dinoflagellates can be segregated into two clusters. One cluster is characterized by MGDG and DGDG possessing the polyunsaturated C18/C18 fatty acids (sn‐1/sn‐2 regiochemistry) octadecapentaenoic acid (18:5(n‐3)) and octadecatetraenoic acid (18:4(n‐3)), while the second cluster possesses eicosapentaenoic acid (20:5(n‐3)) in the sn‐1 position while retaining a polyunsaturated C18 fatty acid in the sn‐2 position. By contrast, Karenia brevis and Karenia mikimotoi have been observed to be enriched in species of MGDG and DGDG, such as 18:5(n‐3)/14:0 MGDG and DGDG, uncommon to peridinin‐containing dinoflagellates. Our objective was to characterize the galactolipids of G. stigmatica to compare it to both peridinin‐containing dinoflagellates and other members of the Kareniaceae to search for insight, such as (a) remnant 14:0 fatty acid‐containing galactolipid(s), into the evolution of its plastid. Our results show that G. stigmatica possesses 20:5(n‐3)/18:5(n‐3) MGDG and DGDG as the primary galactolipids, with little evidence of those galactolipid species enriched in K. brevis and K. mikimotoi. The implications of this for the evolution of the G. stigmatica plastid are discussed.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47595751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new species of the southern hemisphere genus Clymene, C. sutherlandiae, is described based on collections from the Otago coast, south east South Island of New Zealand, and from a site in western Tasmania. Found on mid‐upper intertidal rocks on open coasts, and frequently adjacent to sandy shores, this is a second species for the genus, previously known solely from the type species C. coleana found in the North Island, northern South Island and Chatham Islands of New Zealand.
{"title":"Clymene sutherlandiae sp. nov.: A new species of Bangiales (Rhodophyta) from the southern hemisphere","authors":"W. Nelson","doi":"10.1111/pre.12487","DOIUrl":"https://doi.org/10.1111/pre.12487","url":null,"abstract":"A new species of the southern hemisphere genus Clymene, C. sutherlandiae, is described based on collections from the Otago coast, south east South Island of New Zealand, and from a site in western Tasmania. Found on mid‐upper intertidal rocks on open coasts, and frequently adjacent to sandy shores, this is a second species for the genus, previously known solely from the type species C. coleana found in the North Island, northern South Island and Chatham Islands of New Zealand.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43978143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fábio Nauer, Mariana Cabral Oliveira, E. Plastino, Nair Sumie Yokoya, Mutue Toyota Fujii
Studies on the effects of temperature on physiological processes are essential to model macroalgae biogeographic distribution. Tetrasporophytes of Hypnea pseudomusciformis were collected from three floristic provinces (tropical, transition and warm temperate) along the Brazilian coast (~3.000 km), representing three ecotypes. Specimens were cultured under 20°C, 24°C, 28°C and 32°C for 21 days, then physiological parameters (growth rates, photosynthesis and pigments content) were analyzed. H. pseudomusciformis specimens tolerated a temperature variation from 20°C to 32°C. However, all ecotypes displayed a significant decrease in physiological performance at 32°C in all parameters analyzed. We hypothesized that the H. pseudomusciformis ecotype from the tropical province is already living at its thermal physiological limit, reaching its maximum growth only in the winter months (June to September), whereas a warm temperate ecotype reaches maximum growth in the summer months (December to March). This wide thermal optimum may be the reason for the widespread distribution of this species along the Brazilian coast, allowing it to occupy different thermal environments.
研究温度对生理过程的影响是建立大型藻类生物地理分布模型的必要条件。在巴西沿海(约3.000 km) 3个区系省(热带、过渡型和暖温带)收集到假musciformis四孢子植物，代表3种生态型。分别在20°C、24°C、28°C和32°C条件下培养21 d，分析生长率、光合作用和色素含量等生理参数。假mususciformis标本耐受20°C至32°C的温度变化。然而，所有生态型在32°C时的生理性能均显著下降。我们假设来自热带省的假musciformis生态型已经生活在其热生理极限，仅在冬季(6月至9月)达到最大生长，而温暖温带生态型在夏季(12月至3月)达到最大生长。这种广泛的热最佳可能是这个物种沿着巴西海岸广泛分布的原因，使它能够占据不同的热环境。
{"title":"Thermal tolerance of Hypnea pseudomusciformis ecotypes (Cystocloniaceae, Rhodophyta) related to different floristic provinces along the Brazilian coast","authors":"Fábio Nauer, Mariana Cabral Oliveira, E. Plastino, Nair Sumie Yokoya, Mutue Toyota Fujii","doi":"10.1111/pre.12478","DOIUrl":"https://doi.org/10.1111/pre.12478","url":null,"abstract":"Studies on the effects of temperature on physiological processes are essential to model macroalgae biogeographic distribution. Tetrasporophytes of Hypnea pseudomusciformis were collected from three floristic provinces (tropical, transition and warm temperate) along the Brazilian coast (~3.000 km), representing three ecotypes. Specimens were cultured under 20°C, 24°C, 28°C and 32°C for 21 days, then physiological parameters (growth rates, photosynthesis and pigments content) were analyzed. H. pseudomusciformis specimens tolerated a temperature variation from 20°C to 32°C. However, all ecotypes displayed a significant decrease in physiological performance at 32°C in all parameters analyzed. We hypothesized that the H. pseudomusciformis ecotype from the tropical province is already living at its thermal physiological limit, reaching its maximum growth only in the winter months (June to September), whereas a warm temperate ecotype reaches maximum growth in the summer months (December to March). This wide thermal optimum may be the reason for the widespread distribution of this species along the Brazilian coast, allowing it to occupy different thermal environments.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48647701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Genus Neolyngbya (Cyanobacteria) is widely distributed along coastal region of Okinawa, including in Sunabe beach, Chatan, which is the type locality of Neolyngbya latusa sp. nov. (right). Neolyngbya can be found as macroscopic colony attached to rocks or other hard substrates in intertidal zones. Macroscopic colony images of N. intertidalis sp. nov. (top‐left) and N. latusa (middle‐left). Filament appearances of N. intertidalis (bottom‐left) and N. latusa (bottom‐middle) under a light microscope. Not drawn to scale.
{"title":"Issue Information","authors":"","doi":"10.1111/pre.12476","DOIUrl":"https://doi.org/10.1111/pre.12476","url":null,"abstract":"Genus Neolyngbya (Cyanobacteria) is widely distributed along coastal region of Okinawa, including in Sunabe beach, Chatan, which is the type locality of Neolyngbya latusa sp. nov. (right). Neolyngbya can be found as macroscopic colony attached to rocks or other hard substrates in intertidal zones. Macroscopic colony images of N. intertidalis sp. nov. (top‐left) and N. latusa (middle‐left). Filament appearances of N. intertidalis (bottom‐left) and N. latusa (bottom‐middle) under a light microscope. Not drawn to scale.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47719749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Novelties in nomenclature and typification appearing in Phycological Research 70 (2)","authors":"","doi":"10.1111/pre.12484","DOIUrl":"https://doi.org/10.1111/pre.12484","url":null,"abstract":"","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45765460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Gaiani, M. Rey, À. Tudó, M. Rambla, J. Diogène, M. Campàs, C. Alcaraz
Dinoflagellates of the genera Prorocentrum and Dinophysis are known producers of toxic compounds belonging to the okadaic acid (OA) group. The ingestion of shellfish contaminated with these toxins causes a human disease named diarrheic shellfish poisoning (DSP). In this study, the first record of Prorocentrum panamense, a potential toxin‐producer species, was reported in the Canary Islands together with its toxicological characterization. Prorocentrum panamense cells were collected during April 2017 from natural pools located in the Northeastern part of Gran Canaria. This new record represents an expansion of P. panamense distribution area, previously restricted to the Pacific Ocean, Indian Ocean, Arabian Gulf and the Caribbean, and its introduction mechanisms are discussed. Laboratory cultures of P. panamense were settled and toxin production was assessed in both cell pellets and culture media at four different growth phases (latency, exponential, early stationary and late stationary) implementing LC‐MS/MS and neuro‐2a cell‐based assay (CBA). LC‐MS/MS allowed the identification of OA in the fraction corresponding to the late stationary phase, and tests performed on neuro‐2a cells showed, for most of the fractions, OA‐like activity observable by both cell morphology changes and cell mortality. This information is fundamental for a better understanding of the genus Prorocentrum global distribution, its ecology, and risks associated to toxic producing species.
{"title":"New information about the toxicological profile of Prorocentrum panamense (Prorocentrales, Dinophyceae) and its global distribution","authors":"G. Gaiani, M. Rey, À. Tudó, M. Rambla, J. Diogène, M. Campàs, C. Alcaraz","doi":"10.1111/pre.12479","DOIUrl":"https://doi.org/10.1111/pre.12479","url":null,"abstract":"Dinoflagellates of the genera Prorocentrum and Dinophysis are known producers of toxic compounds belonging to the okadaic acid (OA) group. The ingestion of shellfish contaminated with these toxins causes a human disease named diarrheic shellfish poisoning (DSP). In this study, the first record of Prorocentrum panamense, a potential toxin‐producer species, was reported in the Canary Islands together with its toxicological characterization. Prorocentrum panamense cells were collected during April 2017 from natural pools located in the Northeastern part of Gran Canaria. This new record represents an expansion of P. panamense distribution area, previously restricted to the Pacific Ocean, Indian Ocean, Arabian Gulf and the Caribbean, and its introduction mechanisms are discussed. Laboratory cultures of P. panamense were settled and toxin production was assessed in both cell pellets and culture media at four different growth phases (latency, exponential, early stationary and late stationary) implementing LC‐MS/MS and neuro‐2a cell‐based assay (CBA). LC‐MS/MS allowed the identification of OA in the fraction corresponding to the late stationary phase, and tests performed on neuro‐2a cells showed, for most of the fractions, OA‐like activity observable by both cell morphology changes and cell mortality. This information is fundamental for a better understanding of the genus Prorocentrum global distribution, its ecology, and risks associated to toxic producing species.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44172645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryosuke Okazaki, Narumi Teramoto, A. Carlson, Kiyoko Nakanishi, I. Kudo
In this study, we applied a chemostat culture method, for the first time, to measure the nutrient uptake rate of macroalgae. We examined two methods of measuring the nutrient uptake rate of two macroalgae, Saccharina japonica var. religiosa and Ulva australis, by comparing nutrient uptake kinetics between the chemostat culture and batch culture. In the chemostat culture, the nutrient concentration was kept constant by monitoring the change in nutrient concentration using an Auto Analyzer in real time and adding nutrients to compensate for the macroalgae's nutrient consumption. The nutrient uptake in the chemostat culture could be best fitted to the Michaelis–Menten saturation kinetics. In the batch culture, the nutrient concentration decreased with time, either constantly or exponentially due to a rapid uptake of nutrients by the macroalgae. The nutrient uptake rate in the batch culture generally showed a scattered relationship with nutrient concentration, with a weak fitting to the Michaelis–Menten saturation kinetics. This discrepancy seemed to be partly because the change in nutrient concentration was large between the sampling intervals in the batch culture. Determining an appropriate sampling interval for detectable concentration change is difficult unless the nutrient concentration is measured in real time. Therefore, the application of the chemostat culture method to the measurement of the uptake rate by macroalgae could greatly improve our understanding of nutrient uptake kinetics.
{"title":"Application of chemostat culture to nutrient uptake rate measurements by the macroalgae Saccharina japonica var. religiosa (Phaeophyceae) and Ulva australis (Ulvophyceae)","authors":"Ryosuke Okazaki, Narumi Teramoto, A. Carlson, Kiyoko Nakanishi, I. Kudo","doi":"10.1111/pre.12483","DOIUrl":"https://doi.org/10.1111/pre.12483","url":null,"abstract":"In this study, we applied a chemostat culture method, for the first time, to measure the nutrient uptake rate of macroalgae. We examined two methods of measuring the nutrient uptake rate of two macroalgae, Saccharina japonica var. religiosa and Ulva australis, by comparing nutrient uptake kinetics between the chemostat culture and batch culture. In the chemostat culture, the nutrient concentration was kept constant by monitoring the change in nutrient concentration using an Auto Analyzer in real time and adding nutrients to compensate for the macroalgae's nutrient consumption. The nutrient uptake in the chemostat culture could be best fitted to the Michaelis–Menten saturation kinetics. In the batch culture, the nutrient concentration decreased with time, either constantly or exponentially due to a rapid uptake of nutrients by the macroalgae. The nutrient uptake rate in the batch culture generally showed a scattered relationship with nutrient concentration, with a weak fitting to the Michaelis–Menten saturation kinetics. This discrepancy seemed to be partly because the change in nutrient concentration was large between the sampling intervals in the batch culture. Determining an appropriate sampling interval for detectable concentration change is difficult unless the nutrient concentration is measured in real time. Therefore, the application of the chemostat culture method to the measurement of the uptake rate by macroalgae could greatly improve our understanding of nutrient uptake kinetics.","PeriodicalId":20544,"journal":{"name":"Phycological Research","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48712132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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