2013 年我們參加了三個大型會議, 一個是 1 月在東華大學舉辦的動物行為暨生態學研討會, 一個是 5 月在美國 Colorado 的 Denver 市舉辦的 American Society for Microbiology 的 Annual Meeting, 一個是 8 月在惠蓀林場舉辦的第 18 屆細菌學研討會.
2013 動物行為暨生態學研討會 (東華大學, 花蓮)
斑腿樹蛙蝌蚪的腸道細菌組成以及其可能對宿主的幫助
張永欣1、楊懿如2、陳俊堯1
1慈濟大學生命科學系
2東華大學自然資源學系
外來種斑腿樹蛙與臺灣原生種布氏樹蛙在形態上相似,親緣關係也很接近,然而蝌蚪對環境的選擇和耐受性有相當大的差異。由於腸道細菌能幫助宿主獲得養份而增加存活的機會,本研究檢視這兩種相近樹蛙的蝌蚪在腸道菌相上的差異,並探討對宿主可能提供的幫助。研究中採集三個樣點斑腿樹蛙的蝌蚪,放大16S rDNA 基因片段檢驗菌種組成。我們發現同樣點不同蝌蚪個體間腸道菌相幾乎相同。進行16S rDNA 序列分析後發現主要菌群為 Firmicutes(43%)、Fusobacteria(27%)、Proteobacteria(10%) 和 Actinobacteria(10%),且序列中 76% 為絶對厭氧菌,顯示與環境菌群已有差異。與布氏樹蛙蝌蚪相比,斑腿樹蛙蝌蚪腸道裡出現大量 Fusobacteria 和 Actinobacteria,Firmicutes 佔的比例大幅增加而Bacteroidetes 和 Proteobacteria 減少。Bacteoides 屬(Bacteroidetes門)細菌具有利用植物多醣的能力,序列減少可能代表食物或環境中植物成份的比例降低。斑腿樹蛙蝌蚪腸道細菌序列中 16% 為和 Cetobacterium 菌屬(Fusobacteria門)接近的序列。該菌屬已在人類腸道,魚類腸道和棲息環境被發現,具有合成維生素 B12 的能力,此類細菌的共生是否幫助斑腿樹蛙快速擴張棲地值得進一步研究。
張永欣1、楊懿如2、陳俊堯1
1慈濟大學生命科學系
2東華大學自然資源學系
外來種斑腿樹蛙與臺灣原生種布氏樹蛙在形態上相似,親緣關係也很接近,然而蝌蚪對環境的選擇和耐受性有相當大的差異。由於腸道細菌能幫助宿主獲得養份而增加存活的機會,本研究檢視這兩種相近樹蛙的蝌蚪在腸道菌相上的差異,並探討對宿主可能提供的幫助。研究中採集三個樣點斑腿樹蛙的蝌蚪,放大16S rDNA 基因片段檢驗菌種組成。我們發現同樣點不同蝌蚪個體間腸道菌相幾乎相同。進行16S rDNA 序列分析後發現主要菌群為 Firmicutes(43%)、Fusobacteria(27%)、Proteobacteria(10%) 和 Actinobacteria(10%),且序列中 76% 為絶對厭氧菌,顯示與環境菌群已有差異。與布氏樹蛙蝌蚪相比,斑腿樹蛙蝌蚪腸道裡出現大量 Fusobacteria 和 Actinobacteria,Firmicutes 佔的比例大幅增加而Bacteroidetes 和 Proteobacteria 減少。Bacteoides 屬(Bacteroidetes門)細菌具有利用植物多醣的能力,序列減少可能代表食物或環境中植物成份的比例降低。斑腿樹蛙蝌蚪腸道細菌序列中 16% 為和 Cetobacterium 菌屬(Fusobacteria門)接近的序列。該菌屬已在人類腸道,魚類腸道和棲息環境被發現,具有合成維生素 B12 的能力,此類細菌的共生是否幫助斑腿樹蛙快速擴張棲地值得進一步研究。
兩生類蝌蚪由環境細菌中篩選及建立特有的腸道菌相
張永欣、陳俊堯
慈濟大學生命科學系
腸道菌相的組成平衡直接影響動物的健康。水生動物的腸道與外界環境接觸,其菌相組成有機會持續受到棲地環境菌相的影響。本研究利用五種同水域採集的蝌蚪(澤蛙、莫氏樹蛙、布氏樹蛙、小雨蛙、黑蒙西氏小雨蛙)探討兩生類是否能篩選得到腸道細菌。我們發現蝌蚪腸道菌群和環境菌群幾乎全不同。種內菌相差異遠小於種間差異,顯示宿主各自使用特定機制篩選腸道細菌。底泥中主要的古細菌為 Thaumarchaeota 門(70%),Euryarchaeota 門僅佔 6%,與哺乳類腸道古細菌全為 Euryarchaeota 門的狀況大不相同。腸道內優勢序列主要屬於 Thaumarchaeota,且多同為環境優勢菌種,顯示腸道古細菌主要來自底泥。底泥的優勢真細菌 Betaproteobacteria(26%)、Alphaproteobacteria(20%)和Deltaproteobacteria(20%)均非腸道內的主要菌群,而腸道優勢菌群 Gammaproteobacteria 和 Firmicutes 也只各佔底泥裡的 2%,顯示腸道內真細菌已特化適應腸道內生活,而不易在環境中被偵測到。本研究結果證實蝌蚪菌相主要可能來自環境,而在相同環境菌相中不同蝌蚪各自篩選建立本身獨特的腸道菌相。
張永欣、陳俊堯
慈濟大學生命科學系
腸道菌相的組成平衡直接影響動物的健康。水生動物的腸道與外界環境接觸,其菌相組成有機會持續受到棲地環境菌相的影響。本研究利用五種同水域採集的蝌蚪(澤蛙、莫氏樹蛙、布氏樹蛙、小雨蛙、黑蒙西氏小雨蛙)探討兩生類是否能篩選得到腸道細菌。我們發現蝌蚪腸道菌群和環境菌群幾乎全不同。種內菌相差異遠小於種間差異,顯示宿主各自使用特定機制篩選腸道細菌。底泥中主要的古細菌為 Thaumarchaeota 門(70%),Euryarchaeota 門僅佔 6%,與哺乳類腸道古細菌全為 Euryarchaeota 門的狀況大不相同。腸道內優勢序列主要屬於 Thaumarchaeota,且多同為環境優勢菌種,顯示腸道古細菌主要來自底泥。底泥的優勢真細菌 Betaproteobacteria(26%)、Alphaproteobacteria(20%)和Deltaproteobacteria(20%)均非腸道內的主要菌群,而腸道優勢菌群 Gammaproteobacteria 和 Firmicutes 也只各佔底泥裡的 2%,顯示腸道內真細菌已特化適應腸道內生活,而不易在環境中被偵測到。本研究結果證實蝌蚪菌相主要可能來自環境,而在相同環境菌相中不同蝌蚪各自篩選建立本身獨特的腸道菌相。
環境持續在兩生類蝌蚪發育過程中影響腸道菌相的組成
張永欣、陳俊堯
慈濟大學生命科學系
脊椎動物維持與腸道細菌相互依賴的共生關係。哺乳類的腸道有大量共生細菌,並可藉由與親代共處而傳給子代。兩生類親代在產卵後即離開,蝌蚪孵化後没有機會繼承腸道菌相,迫使兩生類可能無法與細菌建立緊密的共生關係。本研究檢視布氏樹蛙是否利用繁殖時的泡巢做為傳遞腸道細菌的工具,比較親代和環境兩個主要力量對菌相組成造成的影響。我們將同泡巢的蝌蚪放入不同環境中飼養後以 PCR-DGGE 技術檢視蝌蚪腸道菌相,發現蝌蚪腸道菌相和泡巢及池水菌相組成差異很大。同環境同泡巢的蝌蚪具有相近的菌相,同泡巢在不同環境長大的蝌蚪則菌相明顯改變,不同泡巢的蝌蚪放在同來源的池水中培養後,腸道裡開始出現相同菌種,顯示環境是影響菌相的主要力量。一個月後我們將部份蝌蚪移入另一個環境,發現腸道菌相又會受新環境影響而改變。16S rDNA序列庫分析結果指出腸道主要菌群為 Bacteroidetes、Firmicutes 和 Proteobacteria,正好均為哺乳類腸道主要菌群。顯示兩生類可能已有類似哺乳類與腸道菌的共生關係。
張永欣、陳俊堯
慈濟大學生命科學系
脊椎動物維持與腸道細菌相互依賴的共生關係。哺乳類的腸道有大量共生細菌,並可藉由與親代共處而傳給子代。兩生類親代在產卵後即離開,蝌蚪孵化後没有機會繼承腸道菌相,迫使兩生類可能無法與細菌建立緊密的共生關係。本研究檢視布氏樹蛙是否利用繁殖時的泡巢做為傳遞腸道細菌的工具,比較親代和環境兩個主要力量對菌相組成造成的影響。我們將同泡巢的蝌蚪放入不同環境中飼養後以 PCR-DGGE 技術檢視蝌蚪腸道菌相,發現蝌蚪腸道菌相和泡巢及池水菌相組成差異很大。同環境同泡巢的蝌蚪具有相近的菌相,同泡巢在不同環境長大的蝌蚪則菌相明顯改變,不同泡巢的蝌蚪放在同來源的池水中培養後,腸道裡開始出現相同菌種,顯示環境是影響菌相的主要力量。一個月後我們將部份蝌蚪移入另一個環境,發現腸道菌相又會受新環境影響而改變。16S rDNA序列庫分析結果指出腸道主要菌群為 Bacteroidetes、Firmicutes 和 Proteobacteria,正好均為哺乳類腸道主要菌群。顯示兩生類可能已有類似哺乳類與腸道菌的共生關係。
以艾氏樹蛙探討小環境與食卵性對蝌蚪腸道菌相的影響
許雅婷1、張永欣1、陳俊堯1、楊育昌2、何翰蓁3
1慈濟大學生命科學系
2特有生物研究所
3慈濟大學醫學系解剖學科
腸道菌相平衡與否對動物健康扮演的重要的角色。哺乳類動物可經由和親代接觸獲得腸道有益菌群,兩生類的卵通常獨立孵化而降低繼承親代腸道細菌的機會,故腸道細菌主要應由環境篩選獲得。艾氏樹蛙選擇竹筒或樹洞產卵,蝌蚪生長水域與其他兩生類相比較為狹小,而且容易變動。在這樣的小環境中我們預期細菌群聚的多樣性較低, 而且組成中容易在有養份時出現較多的伺機性異營菌。艾氏樹蛙蝌蚪以親代產下的未受精卵為食,是兩生類中少數有機會在孵化後接觸親代的物種。本研究中我們以艾氏樹蛙蝌蚪為材料,探討小環境菌相及食卵習性對蝌蚪腸道菌群組成造成的影響。我們利用PCR-DGGE技術分析蝌蚪腸道細菌的16S rDNA基因片段組成後,發現同竹筒的個體間菌相組成較相似,而採自不同樣點或同樣點不同竹筒的蝌蚪樣本中,腸道菌相的差異明顯。此外,部份蝌蚪腸道菌種可在環境樣本中發現,而且環境細菌多樣性較高,顯示蝌蚪可由環境篩選獲得細菌。分析腸道細菌16S rDNA序列庫後發現蝌蚪腸道細菌主要是Bacteroidetes、Firmicutes、Verrucomicrobia、Gammaproteobacteria 和Betaproteobacteria。這些序列多為新種,已知最近菌種常為哺乳類腸道分離菌,顯示在艾氏樹蛙可能已有類似哺乳類的共生關係。進一步和其他草食性蝌蚪菌相比較後發現艾氏樹蛙蝌蚪腸道內和動物具有共生關係的Bacteroidetes、Verrucomicrobia比例較草食性蝌蚪高,Gammaproteobacteria門中也以腸道內常見的Enterobacteriaceae科細菌為主。顯示艾氏樹蛙可能由親代獲得部份腸道細菌。
許雅婷1、張永欣1、陳俊堯1、楊育昌2、何翰蓁3
1慈濟大學生命科學系
2特有生物研究所
3慈濟大學醫學系解剖學科
腸道菌相平衡與否對動物健康扮演的重要的角色。哺乳類動物可經由和親代接觸獲得腸道有益菌群,兩生類的卵通常獨立孵化而降低繼承親代腸道細菌的機會,故腸道細菌主要應由環境篩選獲得。艾氏樹蛙選擇竹筒或樹洞產卵,蝌蚪生長水域與其他兩生類相比較為狹小,而且容易變動。在這樣的小環境中我們預期細菌群聚的多樣性較低, 而且組成中容易在有養份時出現較多的伺機性異營菌。艾氏樹蛙蝌蚪以親代產下的未受精卵為食,是兩生類中少數有機會在孵化後接觸親代的物種。本研究中我們以艾氏樹蛙蝌蚪為材料,探討小環境菌相及食卵習性對蝌蚪腸道菌群組成造成的影響。我們利用PCR-DGGE技術分析蝌蚪腸道細菌的16S rDNA基因片段組成後,發現同竹筒的個體間菌相組成較相似,而採自不同樣點或同樣點不同竹筒的蝌蚪樣本中,腸道菌相的差異明顯。此外,部份蝌蚪腸道菌種可在環境樣本中發現,而且環境細菌多樣性較高,顯示蝌蚪可由環境篩選獲得細菌。分析腸道細菌16S rDNA序列庫後發現蝌蚪腸道細菌主要是Bacteroidetes、Firmicutes、Verrucomicrobia、Gammaproteobacteria 和Betaproteobacteria。這些序列多為新種,已知最近菌種常為哺乳類腸道分離菌,顯示在艾氏樹蛙可能已有類似哺乳類的共生關係。進一步和其他草食性蝌蚪菌相比較後發現艾氏樹蛙蝌蚪腸道內和動物具有共生關係的Bacteroidetes、Verrucomicrobia比例較草食性蝌蚪高,Gammaproteobacteria門中也以腸道內常見的Enterobacteriaceae科細菌為主。顯示艾氏樹蛙可能由親代獲得部份腸道細菌。
ASM 113rd Annual Meeting (Denver, Colorado, USA)
Starvation-induced phenotypic and genetic diversification of Vibrio vulnificus
Hwajiun Chen1, Chun-Yao Chen2
Institute of Medical Sciences1 and Department of Life Sciences2, Tzu-Chi University,Hualien, Taiwan.
Starvation is a common stress experienced by bacteria living in aquatic environments,and can effectively act as a major selective force in shaping phenotypic presentationof natural populations. In this study we examined the survival and diversificationof Vibrio vulnificus in long-term starvation. Motility, hemolytic, and proteolyticactivities were used as phenotypic indicators to track diversification in starvedpopulation. Phenotypic variants (PVs) were detected at day 4, and graduallydiversified during starvation. Phenotypic diversification was seen in starvedpopulations kept under 1-3% salinity seawater. Cell density and strains affectedthe extent of this diversification. PVs with reduced motility always appearedearly in starved population, before PVs with reduction in proteolytic or hemolyticactivities were detected. We detected various rpoS mutants in survivor populationsafter day 28. Six starvation survivors, including 3 with rpoS mutations and 3without rpoS mutation, were chosen to compete in long-term starvation. All thesestarvation survivors show competitive advantage over parent strain, and 2 of 3 rpoSmutants were more competitive than survivors without rpoS mutation, indicatingthe advantage of losing rpoS. This suggest the reduction in motility, increase inproteolytic activity, reduction in hemolytic activity and lose of rpoS may provideadvantage for V. vulnificus under starvation.
We isolated natural populations of V. vulnificus from marine samples collected inTaiwan, using selective media VVM and TCBS. Phenotypic variation was seenin most natural populations. In contrast to prediction from laboratory results, themajority (54%) of these isolates have higher proteolytic, lower hemolytic activity andsimilar motility compared to 93U204. All 328 isolates (from 11 populations) havecorrect-sized rpoS amplicons as examined by PCR. We sequenced rpoS from 21 PVsof marine isolates, and changes were only detected in 10 of 330 amino acids. Theseresults indicate that although phenotypic diversification can occur when bacteriawere starved in seawater, mutations that reduce proteolytic activity and motility aspredicted advantageous from laboratory results, were not favored in natural marineenvironments.
Hwajiun Chen1, Chun-Yao Chen2
Institute of Medical Sciences1 and Department of Life Sciences2, Tzu-Chi University,Hualien, Taiwan.
Starvation is a common stress experienced by bacteria living in aquatic environments,and can effectively act as a major selective force in shaping phenotypic presentationof natural populations. In this study we examined the survival and diversificationof Vibrio vulnificus in long-term starvation. Motility, hemolytic, and proteolyticactivities were used as phenotypic indicators to track diversification in starvedpopulation. Phenotypic variants (PVs) were detected at day 4, and graduallydiversified during starvation. Phenotypic diversification was seen in starvedpopulations kept under 1-3% salinity seawater. Cell density and strains affectedthe extent of this diversification. PVs with reduced motility always appearedearly in starved population, before PVs with reduction in proteolytic or hemolyticactivities were detected. We detected various rpoS mutants in survivor populationsafter day 28. Six starvation survivors, including 3 with rpoS mutations and 3without rpoS mutation, were chosen to compete in long-term starvation. All thesestarvation survivors show competitive advantage over parent strain, and 2 of 3 rpoSmutants were more competitive than survivors without rpoS mutation, indicatingthe advantage of losing rpoS. This suggest the reduction in motility, increase inproteolytic activity, reduction in hemolytic activity and lose of rpoS may provideadvantage for V. vulnificus under starvation.
We isolated natural populations of V. vulnificus from marine samples collected inTaiwan, using selective media VVM and TCBS. Phenotypic variation was seenin most natural populations. In contrast to prediction from laboratory results, themajority (54%) of these isolates have higher proteolytic, lower hemolytic activity andsimilar motility compared to 93U204. All 328 isolates (from 11 populations) havecorrect-sized rpoS amplicons as examined by PCR. We sequenced rpoS from 21 PVsof marine isolates, and changes were only detected in 10 of 330 amino acids. Theseresults indicate that although phenotypic diversification can occur when bacteriawere starved in seawater, mutations that reduce proteolytic activity and motility aspredicted advantageous from laboratory results, were not favored in natural marineenvironments.
Gut microbial diversity in oophagous tadpole of Kurixalus eiffingeri, a species that breeds in bamboo stump
Ya-Ting Hsu1 2, Chun-Yao Chen1, Han-Chen Ho2
1 Department of Life Science, Tzu-Chi University
2 Department of Anatomy, Tzu-Chi University
Stable and balanced gut microbiota help the host animal to stay healthy. Mammalian youngsters acquire beneficial gut microbes from parents through daily contacts. Amphibian tadpoles generally hatched long after their parents left the spawning sites, therefore their gut microbiota is more likely to derive from environmental sources. Kurixalus eiffingeri utilizes cut bamboo stumps as its oviposition sites, and the hatched tadpoles live in the bamboo cup, a temporary pond that is highly susceptible to environmental changes. Small and changing habitats provide less diverse microbes for the tadpoles to choose from, therefore we expect to see a low-diversity and opportunist-dominated gut microbiota in these tadpoles. On the other hand, these tadpoles are fed with unfertilized eggs from their mother, providing a good chance to obtain gut microbes from parents. We analyzed tadpole gut microbiota by PCR-DGGE and 16S rDNA library. Gut communities showed less DGGE bands but did share some bands with the environmental communities, suggesting the animals recruit some microbes from the environment. Gut microbial compositions among tadpoles collected from the same bamboo stump were highly similar, but the compositions were significantly different among tadpoles collected from different stumps. Bacteroidetes, Firmicutes, Verrucomicrobia, Gammaproteobacteria and Betaproteobacteria are the dominant bacterial phyla found in the analyzed samples. Very few OTUs are shared among different tadpoles, suggesting local environment has strong influence on gut microbiota. We conclude that environment greatly affects K. eiffingeri tadpole gut microbiota, and Gammaproteobacteria opportunists dominate the community.
Ya-Ting Hsu1 2, Chun-Yao Chen1, Han-Chen Ho2
1 Department of Life Science, Tzu-Chi University
2 Department of Anatomy, Tzu-Chi University
Stable and balanced gut microbiota help the host animal to stay healthy. Mammalian youngsters acquire beneficial gut microbes from parents through daily contacts. Amphibian tadpoles generally hatched long after their parents left the spawning sites, therefore their gut microbiota is more likely to derive from environmental sources. Kurixalus eiffingeri utilizes cut bamboo stumps as its oviposition sites, and the hatched tadpoles live in the bamboo cup, a temporary pond that is highly susceptible to environmental changes. Small and changing habitats provide less diverse microbes for the tadpoles to choose from, therefore we expect to see a low-diversity and opportunist-dominated gut microbiota in these tadpoles. On the other hand, these tadpoles are fed with unfertilized eggs from their mother, providing a good chance to obtain gut microbes from parents. We analyzed tadpole gut microbiota by PCR-DGGE and 16S rDNA library. Gut communities showed less DGGE bands but did share some bands with the environmental communities, suggesting the animals recruit some microbes from the environment. Gut microbial compositions among tadpoles collected from the same bamboo stump were highly similar, but the compositions were significantly different among tadpoles collected from different stumps. Bacteroidetes, Firmicutes, Verrucomicrobia, Gammaproteobacteria and Betaproteobacteria are the dominant bacterial phyla found in the analyzed samples. Very few OTUs are shared among different tadpoles, suggesting local environment has strong influence on gut microbiota. We conclude that environment greatly affects K. eiffingeri tadpole gut microbiota, and Gammaproteobacteria opportunists dominate the community.
Microbial diversity associated with rhodophyte Galaxaura filamentosa found in Pacific intertidal zone
Tzu-Yin Chen1, Tsu-Ning Hsieh1, Han-Chen Ho2, Chun-Yao Chen1
1 Department of Life Science, Tzu-Chi University
2 Department of Anatomy, Tzu-Chi University
Diverse microbial communities have established close association with marine macroalga and invertebrates, and may have major impact on host health and fitness. Galaxaura filamentosa is a dominant rhodophyte in intertidal zone in Hualien along the Pacific coast, and can maintain a stable local population thoughout the year, therefore is a good model for studying rhodophyte microbiota. In this study we analyzed the algae-associated bacterial diversity on G. filamentosa using PCR-DGGE and 16S rDNA library analysis. Samples taken from the top, middle, and lower parts of the same plant yielded highly similar microbial composition. Neighboring G. filamentosa individuals, individuals collected at different locations within the same pothole, and individuals collected from 2 adjacent potholes all showed similar microbial composition (ANOSIM, P>0.05), indicating diversification does not occur at meter-level spatial scale. Contrary to the microbial consistency in spatially different samples, individuals collected at different time showed temporal variation. We observed dramatic change in community composition between 2 samples collected in consecutive month. This indicates the composition of macroalgae microbiota is highly dynamic. Analysis of 16S rDNA clone library revealed that the dominant bacterial phyla on G. filamentosa were Cyanobacteria (13%), Proteobacteria (47%) and Bacteroidetes (13%). Many sequences are closely related to sequences previously found on corals. The dominant culturable bacteria genera as measured in summer of 2012 are Vibrio (80%) and Pseudoalteromonas. Microcosm experiment results indicate a week-long shift of salinity from 3.3% to 1.0% did not change the microbial composition on G. filamentosa, suggesting these algae-associated microbial communities are relative stable under environmental fluctuation.
Tzu-Yin Chen1, Tsu-Ning Hsieh1, Han-Chen Ho2, Chun-Yao Chen1
1 Department of Life Science, Tzu-Chi University
2 Department of Anatomy, Tzu-Chi University
Diverse microbial communities have established close association with marine macroalga and invertebrates, and may have major impact on host health and fitness. Galaxaura filamentosa is a dominant rhodophyte in intertidal zone in Hualien along the Pacific coast, and can maintain a stable local population thoughout the year, therefore is a good model for studying rhodophyte microbiota. In this study we analyzed the algae-associated bacterial diversity on G. filamentosa using PCR-DGGE and 16S rDNA library analysis. Samples taken from the top, middle, and lower parts of the same plant yielded highly similar microbial composition. Neighboring G. filamentosa individuals, individuals collected at different locations within the same pothole, and individuals collected from 2 adjacent potholes all showed similar microbial composition (ANOSIM, P>0.05), indicating diversification does not occur at meter-level spatial scale. Contrary to the microbial consistency in spatially different samples, individuals collected at different time showed temporal variation. We observed dramatic change in community composition between 2 samples collected in consecutive month. This indicates the composition of macroalgae microbiota is highly dynamic. Analysis of 16S rDNA clone library revealed that the dominant bacterial phyla on G. filamentosa were Cyanobacteria (13%), Proteobacteria (47%) and Bacteroidetes (13%). Many sequences are closely related to sequences previously found on corals. The dominant culturable bacteria genera as measured in summer of 2012 are Vibrio (80%) and Pseudoalteromonas. Microcosm experiment results indicate a week-long shift of salinity from 3.3% to 1.0% did not change the microbial composition on G. filamentosa, suggesting these algae-associated microbial communities are relative stable under environmental fluctuation.
2013 第 18 屆細菌學研討會
Soil archaeal microbial compositions associated with chemical farmland, organic farmland and afforested land in Hualien rural area
Pei-Yu Hou (侯沛育)1, Shih-Chieh Chang (張世杰)2, Chun-Yao Chen (陳俊堯)1
1 Department of Life Science, Tzu-Chi University (慈濟大學生命科學系)
2 Department of Natural Resources and Environmental Studies, Donghwa University (東華大學自然資源與環境學系)
The Satoyama Initiative aims to conserve sustainable human-influenced natural environments. A balanced land use management can be achieved only after detailed information on the ecological impact associated with each land use type has been established. As the first step, we examined the soil microbial composition of chemical farmland, organic farmland and afforestation land, 3 major land-use types found in Hualien rural area. Soil microbial diversity was similar among these 3 land-use types. The soil archaeal communities in all 3 land-use types are almost exclusively composed of Thaumarchaeota species, but the relative abundance of Terrestrial Group Thaumarchaeota (52%) in the afforested land are much higher than that in agriculture area. We collected soil samples and analyzed microbiota from 4 sites (1 chemical, 1 organic, and 2 afforested sites). NMDS analysis of arhaeal community composition shows that there is variation within sites, but the among-sites variation is much larger. Using microcosms, we demonstrated that application of chemical fertilizer (urea) changed soil microbiota and reduced microbial diversity after 2 weeks, but the microbiota remained largely unchanged after application of organic fertilizer even after 4 weeks. We concluded that chemical farming can quickly alter the soil microbiota, however, diversity and hence ecological functions may not necessarily be changed.
Pei-Yu Hou (侯沛育)1, Shih-Chieh Chang (張世杰)2, Chun-Yao Chen (陳俊堯)1
1 Department of Life Science, Tzu-Chi University (慈濟大學生命科學系)
2 Department of Natural Resources and Environmental Studies, Donghwa University (東華大學自然資源與環境學系)
The Satoyama Initiative aims to conserve sustainable human-influenced natural environments. A balanced land use management can be achieved only after detailed information on the ecological impact associated with each land use type has been established. As the first step, we examined the soil microbial composition of chemical farmland, organic farmland and afforestation land, 3 major land-use types found in Hualien rural area. Soil microbial diversity was similar among these 3 land-use types. The soil archaeal communities in all 3 land-use types are almost exclusively composed of Thaumarchaeota species, but the relative abundance of Terrestrial Group Thaumarchaeota (52%) in the afforested land are much higher than that in agriculture area. We collected soil samples and analyzed microbiota from 4 sites (1 chemical, 1 organic, and 2 afforested sites). NMDS analysis of arhaeal community composition shows that there is variation within sites, but the among-sites variation is much larger. Using microcosms, we demonstrated that application of chemical fertilizer (urea) changed soil microbiota and reduced microbial diversity after 2 weeks, but the microbiota remained largely unchanged after application of organic fertilizer even after 4 weeks. We concluded that chemical farming can quickly alter the soil microbiota, however, diversity and hence ecological functions may not necessarily be changed.
Microbiota of colonial Palythoa anemones are dominated by Endozoicomonas bacteria and Symbiodinium dinoflagellates
Mei-Hsiu Wan (萬美秀)1, Han-Chen Ho (何翰蓁)2, Chun-Yao Chen (陳俊堯)1
1 Department of Life Science (慈濟大學生命科學系)
2 Department of Anatomy, Tzu-Chi University, Hualien (慈濟大學解剖學科)
Cnidarians, including corals and anemones, constitute a major portion of animal flora in coral reef. Like corals, anemones are also involved in nutrient and element cycling, by supporting microbial community. In this study we focused on zoanthids, the dominating cnidarian species, in the intertidal zones in Shitiping area. Composition of Palythoa-associated bacterial community is stable over space and time, with 1 band dominated the community. The major DGGE band was found to be a novel Endozoicomonas species. This species was not universally found in zoanthid species in the same area, suggesting at least some extend of host specificity. Novel species belong to Verrucomicrobia and Epsilonproteobacteria were found. Symbiotic dinoflagellates were detected by electron microscopy and PCR. Multiple symbionts sequences were amplified from each individual anemones, but a common dominant band was seen among samples from 3 adjacent tidal pools. This band was sequenced and identified as a member of a novel Symbiodinium clade. This result reveals previously-unknown microbial diversity in zoanthid anemone, and may contribute to our understanding of the intertidal community.
Mei-Hsiu Wan (萬美秀)1, Han-Chen Ho (何翰蓁)2, Chun-Yao Chen (陳俊堯)1
1 Department of Life Science (慈濟大學生命科學系)
2 Department of Anatomy, Tzu-Chi University, Hualien (慈濟大學解剖學科)
Cnidarians, including corals and anemones, constitute a major portion of animal flora in coral reef. Like corals, anemones are also involved in nutrient and element cycling, by supporting microbial community. In this study we focused on zoanthids, the dominating cnidarian species, in the intertidal zones in Shitiping area. Composition of Palythoa-associated bacterial community is stable over space and time, with 1 band dominated the community. The major DGGE band was found to be a novel Endozoicomonas species. This species was not universally found in zoanthid species in the same area, suggesting at least some extend of host specificity. Novel species belong to Verrucomicrobia and Epsilonproteobacteria were found. Symbiotic dinoflagellates were detected by electron microscopy and PCR. Multiple symbionts sequences were amplified from each individual anemones, but a common dominant band was seen among samples from 3 adjacent tidal pools. This band was sequenced and identified as a member of a novel Symbiodinium clade. This result reveals previously-unknown microbial diversity in zoanthid anemone, and may contribute to our understanding of the intertidal community.