The Experts below are selected from a list of 2301 Experts worldwide ranked by ideXlab platform
Yoshihiro Takaki - One of the best experts on this subject based on the ideXlab platform.
-
Algivore or phototroph? Plakobranchus ocellatus (Gastropoda) continuously acquires kleptoplasts and nutrition from multiple algal species in nature. PLoS
2012Co-Authors: Taro Maeda, Yoshito Chikaraishi, Euichi Hirose, Masaru Kawato, Kiyotaka Takishita, Takao Yoshida, Heroen Verbruggen, Jiro Tanaka, Shigeru Shimamura, Yoshihiro TakakiAbstract:The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a Photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (Photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P
-
Algivore or Phototroph? Plakobranchus ocellatus (Gastropoda) Continuously Acquires Kleptoplasts and Nutrition from Multiple Algal Species in Nature
2012Co-Authors: Taro Maeda, Yoshito Chikaraishi, Euichi Hirose, Masaru Kawato, Kiyotaka Takishita, Takao Yoshida, Heroen Verbruggen, Jiro Tanaka, Shigeru Shimamura, Yoshihiro TakakiAbstract:The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a Photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (Photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae.
Jin Wang - One of the best experts on this subject based on the ideXlab platform.
-
Fast and Easy Quantitative Characterization of Methanotroph-Photoautotroph Cocultures.
Biotechnology and Bioengineering, 2020Co-Authors: Kiumars Badr, William Whelan, Jin WangAbstract:Recent research has demonstrated that synthetic methanotroph-Photoautotroph cocultures offer a highly promising route to convert biogas into value-added products. However, there is a lack of techniques for fast and accurate characterization of cocultures, such as determining the individual biomass concentration of each organism in real-time. To address this unsolved challenge, we propose an experimental-computational protocol for fast, easy and accurate quantitative characterization of the methanotroph-Photoautotroph cocultures. Besides determining the individual biomass concentration of each organism in the coculture, the protocol can also obtain the individual consumption and production rates of O2 and CO2 for the methanotroph and Photoautotroph, respectively. The accuracy and effectiveness of the proposed protocol was demonstrated using two model coculture pairs, Methylomicrobium alcaliphilum 20ZR - Synechococcus sp. PCC7002 that prefers high pH high salt condition, and Methylococcus capsulatus - Chlorella sorokiniana that prefers low salt and neutral pH medium. The performance of the proposed protocol was compared with a flow cytometry based cell counting approach. The experimental results show that the proposed protocol is much easier to carry out and delivers faster and more accurate results in measuring individual biomass concentration than the cell counting approach without requiring any special equipment. This article is protected by copyright. All rights reserved.
-
Fast and Easy Quantitative Characterization of Methanotroph-Photoautotroph Cocultures
2020Co-Authors: Kiumars Badr, William Whalen, Jin WangAbstract:Recent research has demonstrated that synthetic methanotroph-Photoautotroph cocultures offer a highly promising route to convert biogas into value-added products. However, there is a lack of techniques for fast and accurate characterization of cocultures, such as determining the individual biomass concentration of each organism in real-time. To address this unsolved challenge, we propose an experimental-computational protocol for fast, easy and accurate quantitative characterization of the methanotroph-Photoautotroph cocultures. Besides determining the individual biomass concentration of each organism in the coculture, the protocol can also obtain the individual consumption and production rates of O2 and CO2 for the methanotroph and Photoautotroph, respectively. The accuracy and effectiveness of the proposed protocol was demonstrated using two model coculture pairs, Methylomicrobium alcaliphilum 20ZR - Synechococcus sp. PCC7002 that prefers high pH high salt condition, and Methylococcus capsulatus - Chlorella sorokiniana that prefers low salt and neutral pH medium. The performance of the proposed protocol was compared with a flow cytometry based cell counting approach. The experimental results show that the proposed protocol is much easier to carry out and delivers faster and more accurate results in measuring individual biomass concentration than the cell counting approach without requiring any special equipment.
-
Photoautotroph-Methanotroph Coculture – A Flexible Platform for Efficient Biological CO2-CH4 Co-utilization
IFAC-PapersOnLine, 2019Co-Authors: Kiumars Badr, Matthew Hilliard, Nathan R. M. Roberts, Jin WangAbstract:Abstract Industrial, municipal, and agricultural waste streams contain stranded organic carbon, which can be converted into biogas through anaerobic digestion. It has been demonstrated that biogas has immense potential as a renewable feedstock for producing high-density fuels and commodity chemicals. However, the utilization of biogas presents a significant challenge due to its low pressure and presence of contaminants such as H 2 S, ammonia, and volatile organic carbon compounds. To tap into this immense potential, effective biotechnologies that co-utilize both CO 2 and CH 4 are needed. Using the basic metabolic coupling principles utilized by many natural consortia, we have demonstrated that Photoautotroph-methanotroph co-cultures offers a flexible and highly promising platform for biological CO 2 /CH 4 co-utilization. In this work, we present the very first effort to quantitatively model the growth dynamics of a Photoautotroph-methanotroph coculture, as well as the experimental and computational tools that are required to characterize the coculture. Together, these advancements will enable us to further examine the potential interspecies interactions within the coculture.
-
Photoautotroph methanotroph coculture a flexible platform for efficient biological co2 ch4 co utilization
IFAC-PapersOnLine, 2019Co-Authors: Kiumars Badr, Matthew Hilliard, Nathan Roberts, Jin WangAbstract:Abstract Industrial, municipal, and agricultural waste streams contain stranded organic carbon, which can be converted into biogas through anaerobic digestion. It has been demonstrated that biogas has immense potential as a renewable feedstock for producing high-density fuels and commodity chemicals. However, the utilization of biogas presents a significant challenge due to its low pressure and presence of contaminants such as H 2 S, ammonia, and volatile organic carbon compounds. To tap into this immense potential, effective biotechnologies that co-utilize both CO 2 and CH 4 are needed. Using the basic metabolic coupling principles utilized by many natural consortia, we have demonstrated that Photoautotroph-methanotroph co-cultures offers a flexible and highly promising platform for biological CO 2 /CH 4 co-utilization. In this work, we present the very first effort to quantitatively model the growth dynamics of a Photoautotroph-methanotroph coculture, as well as the experimental and computational tools that are required to characterize the coculture. Together, these advancements will enable us to further examine the potential interspecies interactions within the coculture.
Hiroshi Kitazato - One of the best experts on this subject based on the ideXlab platform.
-
P423-TH NITROGEN ISOTOPIC COMPOSITION OF BIOLOGICAL CHLOROPHYLLS AND THEIR DEPOSITIONAL DERIVATIVES IN GEOLOGICAL SEDIMENTS
2014Co-Authors: Yoshito Chikaraishi, Hiroshi Kitazato, Shinya NomotoAbstract:Chlorophylls are antenna pigments directly related to the photosynthetic processes of Photoautotrophs. They and their depositional derivatives such as pheophytins and pyropheophytins are abundantly found in oceanic and lacustrine sediments (e.g. Keely and Maxwell, 1991). Therefore, they have widely and conventionally been used as definitive biomarkers of Photoautotrophic activity in the aquatic surface environment (e.g. Sanger, 1998; Nakajima et al., 2003). Moreover, since chlorophylls contain hydrogen, carbon, and nitrogen, their isotopic compositions could record multiple information on the hydrologic and nutrient cycles in the environment where the Photoautotrophs grow (e.g. Chikaraishi et al., 2005). Particularly, nitrogen isotopic composition of chlorophylls and their derivatives (including alkylporphyrins) is a potentially unique proxy for the reconstruction of nitrogen cycle in the geological past as well as modern aquatic environment. However, little information is available for the isotopic relationship among different chlorophyll species within a single Photoautotroph, as well as for the isotopic modification associated with the structural change (e.g. chlorophyll to pheophytin) during depositional processes in the water column and sediments
-
Diazotrophic cyanobacteria as the major Photoautotrophs during mid-Cretaceous oceanic anoxic events: Nitrogen and carbon isotopic evidence from sedimentary porphyrin
Organic Geochemistry, 2008Co-Authors: Yuichiro Kashiyama, Hiroshi Kitazato, Shinya Nomoto, Nanako O. Ogawa, Junichiro Kuroda, Motoo Shiro, Ryuji Tada, Naohiko OhkouchiAbstract:Abstract We determined both the nitrogen and carbon isotopic compositions of nickel-chelated deoxophylloerythroetioporphyrin (Ni DPEP), a major sedimentary porphyrin extracted from the Livello Selli and Livello Bonarelli black shales deposited in the western Tethys Sea during mid-Cretaceous oceanic anoxic events (OAEs). Based on empirical isotopic relationships between the tetrapyrrole nuclei of chlorophylls and Photoautotroph cells, we estimate that the mean nitrogen isotopic composition of the entire Photoautotrophic communities during these periods ranged from −2‰ to +1‰. This result strongly suggests that N2-fixation was an important primary process in Photoautotrophic production during these OAEs. The estimated carbon isotopic composition of the Photoautotrophs was elevated (between −20‰ and −22‰) relative to typical Cretaceous examples, indicating as much as a 5‰ reduction in the magnitude of carbon isotopic fractionation associated with photosynthesis during OAEs in the western Tethys Sea. This anomaly can be well explained if cyanobacteria were the dominant producers because they commonly conduct β-carboxylation and/or active transport of carbon substrates, resulting in reduced carbon isotopic fractionation. We therefore conclude that diazotrophic cyanobacteria were the dominant components of primary production during OAE-1a and OAE-2 in the western Tethys Sea.
-
The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2
Biogeosciences, 2006Co-Authors: Naohiko Ohkouchi, Nanako O. Ogawa, Yuichiro Kashiyama, Junichiro Kuroda, Hiroshi KitazatoAbstract:Abstract. In Livello Bonarelli black shale deposited during Cretaceous Oceanic Anoxic Event 2 (OAE-2, ca. 94 Ma), nitrogen isotopic compositions of bulk sediments are mostly in a narrow range from –2.7 to –0.7‰. We also determined molecular distribution and nitrogen isotopic compositions of geoporphyrins extracted from the black shale. The nitrogen isotopic compositions of C32 Ni deoxophylloerythroetioporphyrin (DPEP) and total Ni porphyrins are –3.5 and –3.3‰, respectively, leading us to the estimation that the mean nitrogen isotopic composition of Photoautotrophic cells were around +1‰ during the formation of Bonarelli black shale. This value is suggestive of N2-fixation, a dominant process for these Photoautotrophs when assimilating nitrogen. Furthermore, Ni-chelated C32 DPEP, derived mainly from chlorophyll a had the highest concentration. Based on this evidence, we conclude that diazotrophic cyanobacteria were major primary producers during that time. Cyanobacteria may be key Photoautotrophs during the formation of black shale type sediments intermittently observed throughout the later half of the Earth's history, and hence may have played a crucial role in the evolution of geochemical cycles even in the later half of the Earth's history.
Naohiko Ohkouchi - One of the best experts on this subject based on the ideXlab platform.
-
Diazotrophic cyanobacteria as the major Photoautotrophs during mid-Cretaceous oceanic anoxic events: Nitrogen and carbon isotopic evidence from sedimentary porphyrin
Organic Geochemistry, 2008Co-Authors: Yuichiro Kashiyama, Hiroshi Kitazato, Shinya Nomoto, Nanako O. Ogawa, Junichiro Kuroda, Motoo Shiro, Ryuji Tada, Naohiko OhkouchiAbstract:Abstract We determined both the nitrogen and carbon isotopic compositions of nickel-chelated deoxophylloerythroetioporphyrin (Ni DPEP), a major sedimentary porphyrin extracted from the Livello Selli and Livello Bonarelli black shales deposited in the western Tethys Sea during mid-Cretaceous oceanic anoxic events (OAEs). Based on empirical isotopic relationships between the tetrapyrrole nuclei of chlorophylls and Photoautotroph cells, we estimate that the mean nitrogen isotopic composition of the entire Photoautotrophic communities during these periods ranged from −2‰ to +1‰. This result strongly suggests that N2-fixation was an important primary process in Photoautotrophic production during these OAEs. The estimated carbon isotopic composition of the Photoautotrophs was elevated (between −20‰ and −22‰) relative to typical Cretaceous examples, indicating as much as a 5‰ reduction in the magnitude of carbon isotopic fractionation associated with photosynthesis during OAEs in the western Tethys Sea. This anomaly can be well explained if cyanobacteria were the dominant producers because they commonly conduct β-carboxylation and/or active transport of carbon substrates, resulting in reduced carbon isotopic fractionation. We therefore conclude that diazotrophic cyanobacteria were the dominant components of primary production during OAE-1a and OAE-2 in the western Tethys Sea.
-
The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2
Biogeosciences, 2006Co-Authors: Naohiko Ohkouchi, Nanako O. Ogawa, Yuichiro Kashiyama, Junichiro Kuroda, Hiroshi KitazatoAbstract:Abstract. In Livello Bonarelli black shale deposited during Cretaceous Oceanic Anoxic Event 2 (OAE-2, ca. 94 Ma), nitrogen isotopic compositions of bulk sediments are mostly in a narrow range from –2.7 to –0.7‰. We also determined molecular distribution and nitrogen isotopic compositions of geoporphyrins extracted from the black shale. The nitrogen isotopic compositions of C32 Ni deoxophylloerythroetioporphyrin (DPEP) and total Ni porphyrins are –3.5 and –3.3‰, respectively, leading us to the estimation that the mean nitrogen isotopic composition of Photoautotrophic cells were around +1‰ during the formation of Bonarelli black shale. This value is suggestive of N2-fixation, a dominant process for these Photoautotrophs when assimilating nitrogen. Furthermore, Ni-chelated C32 DPEP, derived mainly from chlorophyll a had the highest concentration. Based on this evidence, we conclude that diazotrophic cyanobacteria were major primary producers during that time. Cyanobacteria may be key Photoautotrophs during the formation of black shale type sediments intermittently observed throughout the later half of the Earth's history, and hence may have played a crucial role in the evolution of geochemical cycles even in the later half of the Earth's history.
Yoshito Chikaraishi - One of the best experts on this subject based on the ideXlab platform.
-
P423-TH NITROGEN ISOTOPIC COMPOSITION OF BIOLOGICAL CHLOROPHYLLS AND THEIR DEPOSITIONAL DERIVATIVES IN GEOLOGICAL SEDIMENTS
2014Co-Authors: Yoshito Chikaraishi, Hiroshi Kitazato, Shinya NomotoAbstract:Chlorophylls are antenna pigments directly related to the photosynthetic processes of Photoautotrophs. They and their depositional derivatives such as pheophytins and pyropheophytins are abundantly found in oceanic and lacustrine sediments (e.g. Keely and Maxwell, 1991). Therefore, they have widely and conventionally been used as definitive biomarkers of Photoautotrophic activity in the aquatic surface environment (e.g. Sanger, 1998; Nakajima et al., 2003). Moreover, since chlorophylls contain hydrogen, carbon, and nitrogen, their isotopic compositions could record multiple information on the hydrologic and nutrient cycles in the environment where the Photoautotrophs grow (e.g. Chikaraishi et al., 2005). Particularly, nitrogen isotopic composition of chlorophylls and their derivatives (including alkylporphyrins) is a potentially unique proxy for the reconstruction of nitrogen cycle in the geological past as well as modern aquatic environment. However, little information is available for the isotopic relationship among different chlorophyll species within a single Photoautotroph, as well as for the isotopic modification associated with the structural change (e.g. chlorophyll to pheophytin) during depositional processes in the water column and sediments
-
Algivore or phototroph? Plakobranchus ocellatus (Gastropoda) continuously acquires kleptoplasts and nutrition from multiple algal species in nature. PLoS
2012Co-Authors: Taro Maeda, Yoshito Chikaraishi, Euichi Hirose, Masaru Kawato, Kiyotaka Takishita, Takao Yoshida, Heroen Verbruggen, Jiro Tanaka, Shigeru Shimamura, Yoshihiro TakakiAbstract:The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a Photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (Photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P
-
Algivore or Phototroph? Plakobranchus ocellatus (Gastropoda) Continuously Acquires Kleptoplasts and Nutrition from Multiple Algal Species in Nature
2012Co-Authors: Taro Maeda, Yoshito Chikaraishi, Euichi Hirose, Masaru Kawato, Kiyotaka Takishita, Takao Yoshida, Heroen Verbruggen, Jiro Tanaka, Shigeru Shimamura, Yoshihiro TakakiAbstract:The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a Photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (Photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae.