360 research outputs found
Green Payments and Dual Policy Goals
No full textJinhua Zhao, and two anonymous reviewers for insightful comments. Valuable guidance from Editor Robert Innes is especially acknowledged. Errors and omissions are the responsibility of the author. This publication is available online on the CARD Web site: www.card.iastate.edu. Permission is granted to reproduce this information with appropriate attribution to the author. Questions or comments about the contents of this paper should be directed to Hongli Feng, 57
A New Anthracene Derivative from Marine Streptomyces sp. W007 Exhibiting Highly and Selectively Cytotoxic Activities
No full textA new anthracene derivative, 3-hydroxy-1-keto-3-methyl-8-methoxy-1,2,3,4-tetrahydro-benz[α]anthracene, was isolated from the marine strain Streptomyces sp. W007, and its structure was established by spectroscopic analysis including mass spectra, 1D- and 2D-NMR (1H–1H COSY, HMBC, HSQC and NOESY) experiments. 3-hydroxy-1-keto-3-methyl-8-methoxy-1,2,3,4-tetrahydro-benz[α]anthracene showed cytotoxicity against human lung adenocarcinoma cell line A549
Transcriptomic analysis of Synechocystis sp PCC6803 under low-temperature stress
No full textIn this study, cDNA microarrays were developed from 3569 mRNA reads to analyze the expression profiles of the transcriptomes of Synechocystis sp. PCC6803 under low temperature (LT) stress. Among the genes on the cDNA microarrays, 899 LT-affected genes exhibited a 1.5-fold (or greater) difference in expression compared with the genes from normal unstressed Synechocystis sp. PCC6803. Of the differentially expressed genes, 353 were up-regulated and 246 were down-regulated. The results showed that genes involved in photosynthesis were activated at LT (10A degrees C), including genes for photosystem I, photosystem II, photosynthetic electron transport, and cytochrome b6/f complex. Moreover, desB, one of four genes that encode the fatty acid desaturases, was also induced by LT. However, the LT conditions to some degree enhanced the transcription of some genes. In addition, LT (10A degrees C) may reduce cellular motility by regulating the transcription of spkA (sll1575), a serine/threonine protein kinase. The results reported in this study may contribute to a better understanding of the responses of the Synechocystis cell to LT, including pathways involved in photosynthesis and repair.In this study, cDNA microarrays were developed from 3569 mRNA reads to analyze the expression profiles of the transcriptomes of Synechocystis sp. PCC6803 under low temperature (LT) stress. Among the genes on the cDNA microarrays, 899 LT-affected genes exhibited a 1.5-fold (or greater) difference in expression compared with the genes from normal unstressed Synechocystis sp. PCC6803. Of the differentially expressed genes, 353 were up-regulated and 246 were down-regulated. The results showed that genes involved in photosynthesis were activated at LT (10A degrees C), including genes for photosystem I, photosystem II, photosynthetic electron transport, and cytochrome b6/f complex. Moreover, desB, one of four genes that encode the fatty acid desaturases, was also induced by LT. However, the LT conditions to some degree enhanced the transcription of some genes. In addition, LT (10A degrees C) may reduce cellular motility by regulating the transcription of spkA (sll1575), a serine/threonine protein kinase. The results reported in this study may contribute to a better understanding of the responses of the Synechocystis cell to LT, including pathways involved in photosynthesis and repair
Vegetation Mapping of Mammoth Cave National Park Using Multispectral Imagery
No full textVegetation Mapping of Mammoth Cave National Park Using Multispectral Imagery
Author: Hongli Yang and Robin Q. Zhang (Mentor)
Up-to-date and detailed vegetation map provides critical information for habitat management. In addition, a vegetation map is necessary for the Park’s Fire Management, for classification of fuel types, and for delineation of fire management units. There have been several attempts of vegetation mapping in 1934, 1975 and 1997. Recent advancements in mapping technology and the availability of high resolution Lidar data call for a new vegetation map for the Park’s management team.
For my research, I will use Landsat-8 Operational Land Imager (OLI) imagery as the main data source for analysis. Obtained from USGS between June 2015 and February 2016, Landsat-8 dataset will cover Mammoth Cave National Park in 30m pixels for the multispectral band and 15m for the panchromatic band, during both the leaf-on and leaf-off seasons. I will apply Landsat-8 dataset to categorize vegetation types according to their different reflectance characteristics. Utilizing both leaf-off and leaf-on images will distinguish coniferous and deciduous trees better. In addition, I plan to use a vegetation index to identify specific vegetation species. To test classification accuracy, I will use the field plots for different vegetation categories. The classification results will also be compared to 2011 National Land Cover Image
Genomewide Analysis of Carotenoid Cleavage Dioxygenases in Unicellular and Filamentous Cyanobacteria
No full textCarotenoid cleavage dioxygenases (CCDs) are a group of enzymes that catalyze the oxidative cleavage steps from carotenoids to various carotenoid cleavage products. Some ccd genes have been identified and encoded enzymes functionally characterized in many higher plants, but little in cyanobacteria. We performed a comparative analysis of ccd sequences and explored their distribution, classification, phylogeny, evolution, and structure among 37 cyanobacteria. Totally 61 putative ccd sequences were identified, which are abundant in Acaryochloris marina MBIC 11017, filamentous N-2-fixing cyanobacteria, and unicellular cyanobacterial Cyanothece. According to phylogenetic trees of 16S rDNA and CCD, nced and ccd8 genes occur later than the divergence of ccd7, apco, and ccd1. All CCD enzymes share conserved basic structure domains constituted by a single loop formed with seven beta-strands and one helix. In this paper, a general framework of sequence-function-evolution connection for the ccd has been revealed, which may provide new insight for functional investigation.Carotenoid cleavage dioxygenases (CCDs) are a group of enzymes that catalyze the oxidative cleavage steps from carotenoids to various carotenoid cleavage products. Some ccd genes have been identified and encoded enzymes functionally characterized in many higher plants, but little in cyanobacteria. We performed a comparative analysis of ccd sequences and explored their distribution, classification, phylogeny, evolution, and structure among 37 cyanobacteria. Totally 61 putative ccd sequences were identified, which are abundant in Acaryochloris marina MBIC 11017, filamentous N-2-fixing cyanobacteria, and unicellular cyanobacterial Cyanothece. According to phylogenetic trees of 16S rDNA and CCD, nced and ccd8 genes occur later than the divergence of ccd7, apco, and ccd1. All CCD enzymes share conserved basic structure domains constituted by a single loop formed with seven beta-strands and one helix. In this paper, a general framework of sequence-function-evolution connection for the ccd has been revealed, which may provide new insight for functional investigation
Molecular Evolution of Lycopene Cyclases Involved in the Formation of Carotenoids in Eukaryotic Algae
No full textCarotenoids play crucial roles in structure and function of the photosynthetic apparatus of bacteria, algae, and higher plants. The formation of carotenoids from lycopene is catalyzed by the enzyme lycopene cyclase (LCY), which is structurally and functionally conserved in all organisms. A comparative genomic analysis regarding the LCY revealed that the higher plant (Arabidopsis thaliana) and the green alga (Ostreococcus sp. RCC809, Ostreococcus tauri, Ostreococcus lucimarinus, Micromonas sp. RCC299, Micromonas pusiua, Chlorella vulgaris, Volvox carteri, and Coccomyxa sp. C-169) possess two different LCY (beta- and epsilon-type). This indicated that an ancient gene duplication event must have occurred, which produced two classes of LCY in algae. However, some other green alga retained only one class of LCY, such as Haematococcus pluvialis (beta), Dunaliella salina (beta), Chlamydomonas reinhardtii (epsilon), and Chlorella sp. NC64A (epsilon), and the other gene copy was lost in these species. Furthermore, the similar LCY lost occurred in red alga (Cyanidioschyzon merolae) and Heterokontophyta (Phaeodactylum tricornutum and Thalassiosira pseudonana), which possess only the LCYB. In addition, the protein sequence of LCYB is highly similar to capsanthin-capsorubin synthase (CCS), which is another carotenogenic enzyme of plants. As a result, it is proposed that the CCS evolved from a duplicated LCYB. The discovery of two classes of LCY families in some algae suggests that carotenoid biosynthesis is differentially regulated in response to development and environmental stress in these algae, like members of LCY families are differentially regulated during development or stress in some higher plants.Carotenoids play crucial roles in structure and function of the photosynthetic apparatus of bacteria, algae, and higher plants. The formation of carotenoids from lycopene is catalyzed by the enzyme lycopene cyclase (LCY), which is structurally and functionally conserved in all organisms. A comparative genomic analysis regarding the LCY revealed that the higher plant (Arabidopsis thaliana) and the green alga (Ostreococcus sp. RCC809, Ostreococcus tauri, Ostreococcus lucimarinus, Micromonas sp. RCC299, Micromonas pusiua, Chlorella vulgaris, Volvox carteri, and Coccomyxa sp. C-169) possess two different LCY (beta- and epsilon-type). This indicated that an ancient gene duplication event must have occurred, which produced two classes of LCY in algae. However, some other green alga retained only one class of LCY, such as Haematococcus pluvialis (beta), Dunaliella salina (beta), Chlamydomonas reinhardtii (epsilon), and Chlorella sp. NC64A (epsilon), and the other gene copy was lost in these species. Furthermore, the similar LCY lost occurred in red alga (Cyanidioschyzon merolae) and Heterokontophyta (Phaeodactylum tricornutum and Thalassiosira pseudonana), which possess only the LCYB. In addition, the protein sequence of LCYB is highly similar to capsanthin-capsorubin synthase (CCS), which is another carotenogenic enzyme of plants. As a result, it is proposed that the CCS evolved from a duplicated LCYB. The discovery of two classes of LCY families in some algae suggests that carotenoid biosynthesis is differentially regulated in response to development and environmental stress in these algae, like members of LCY families are differentially regulated during development or stress in some higher plants
Vegetation Mapping of Mammoth Cave National Park Using Multispectral Imagery
No full textVegetation Mapping of Mammoth Cave National Park Using Multispectral Imagery
Author: Hongli Yang and Robin Q. Zhang (Mentor)
Up-to-date and detailed vegetation map provides critical information for habitat management. In addition, a vegetation map is necessary for the Park’s Fire Management, for classification of fuel types, and for delineation of fire management units. There have been several attempts of vegetation mapping in 1934, 1975 and 1997. Recent advancements in mapping technology and the availability of high resolution Lidar data call for a new vegetation map for the Park’s management team.
For my research, I will use Landsat-8 Operational Land Imager (OLI) imagery as the main data source for analysis. Obtained from USGS between June 2015 and February 2016, Landsat-8 dataset will cover Mammoth Cave National Park in 30m pixels for the multispectral band and 15m for the panchromatic band, during both the leaf-on and leaf-off seasons. I will apply Landsat-8 dataset to categorize vegetation types according to their different reflectance characteristics. Utilizing both leaf-off and leaf-on images will distinguish coniferous and deciduous trees better. In addition, I plan to use a vegetation index to identify specific vegetation species. To test classification accuracy, I will use the field plots for different vegetation categories. The classification results will also be compared to 2011 National Land Cover Image.
In conclusion, my research will produce a new vegetation map for the Mammoth Cave National Park. These maps will provide critical information for habitat and fire management.
Keywords: Mammoth Cave National Park, Landsat-8 OLI, vegetation mapping, National Land Cover Imag
Gene cloning and expression profile of a novel carotenoid hydroxylase (CYP97C) from the green alga Haematococcus pluvialis
No full textA full-length complementary DNA (cDNA) sequence of epsilon-ring CHY (designated Haecyp97c) was cloned from the green alga Haematococcus pluvialis by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends methods. The Haecyp97c cDNA sequence was 1,995 base pairs (bp) in length, which contained a 1,620-bp open reading frame, a 46-bp 5'-untranslated region (UTR), and a 329-bp 3'-UTR with the characteristic of the poly (A) tail. The deduced protein had a calculated molecular mass of 58.71 kDa with an estimated isoelectric point of 7.94. Multiple alignment analysis revealed that the deduced amino acid sequence of HaeCYP97C shared high identity of 72-85 % with corresponding CYP97Cs from other eukaryotes. The catalytic motifs of cytochrome P450s were detected in the amino acid sequence of HaeCYP97C. The transcriptional levels of Haecyp97c and xanthophylls accumulation under high light (HL) stress have been examined. The results revealed that Haecyp97c transcript was strongly increased after 13-28 h under HL stress. Meanwhile, the concentrations of chlorophylls, carotenes, and lutein were decreased, and zeaxanthin and astaxanthin concentrations were increased rapidly, respectively. These facts indicated that HaeCYP97C was perhaps involved in xanthophyll biosynthesis, which plays an important role in adaption to HL for H. pluvialis.A full-length complementary DNA (cDNA) sequence of epsilon-ring CHY (designated Haecyp97c) was cloned from the green alga Haematococcus pluvialis by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends methods. The Haecyp97c cDNA sequence was 1,995 base pairs (bp) in length, which contained a 1,620-bp open reading frame, a 46-bp 5'-untranslated region (UTR), and a 329-bp 3'-UTR with the characteristic of the poly (A) tail. The deduced protein had a calculated molecular mass of 58.71 kDa with an estimated isoelectric point of 7.94. Multiple alignment analysis revealed that the deduced amino acid sequence of HaeCYP97C shared high identity of 72-85 % with corresponding CYP97Cs from other eukaryotes. The catalytic motifs of cytochrome P450s were detected in the amino acid sequence of HaeCYP97C. The transcriptional levels of Haecyp97c and xanthophylls accumulation under high light (HL) stress have been examined. The results revealed that Haecyp97c transcript was strongly increased after 13-28 h under HL stress. Meanwhile, the concentrations of chlorophylls, carotenes, and lutein were decreased, and zeaxanthin and astaxanthin concentrations were increased rapidly, respectively. These facts indicated that HaeCYP97C was perhaps involved in xanthophyll biosynthesis, which plays an important role in adaption to HL for H. pluvialis
Methyl jasmonate- or gibberellins A(3)-induced astaxanthin accumulation is associated with up-regulation of transcription of beta-carotene ketolase genes (bkts) in microalga Haematococcus pluvialis
No full textThe microalga Haematococcus pluvialis accumulates astaxanthin in response to abiotic stresses. Since methyl jasmonate (MJ) and gibberellins A(3) (GA(3)) are involved in the stress responses of plants, the impact of these compounds on astaxanthin metabolism was studied. Alga cells treated separately with MJ and GA(3) accumulated more astaxanthin than the controls. MJ and GA(3) treatment increased the transcription of three beta-carotene ketolase genes (bkts). MJ- and GA(3)-responsive cis-acting elements were identified in the 5'-flanking regions of bkt genes. These results suggest that MJ and GA(3) constitute molecular signals in the network of astaxanthin accumulation. Induction of astaxanthin accumulation by MJ or GA(3) without any other stimuli presents an attractive application potential. (C) 2010 Elsevier Ltd. All rights reserved
Genome-wide analysis of putative peroxiredoxin in unicellular and filamentous cyanobacteria
No full textAbstract Background Cyanobacteria are photoautotrophic prokaryotes with wide variations in genome sizes and ecological habitats. Peroxiredoxin (PRX) is an important protein that plays essential roles in protecting own cells against reactive oxygen species (ROS). PRXs have been identified from mammals, fungi and higher plants. However, knowledge on cyanobacterial PRXs still remains obscure. With the availability of 37 sequenced cyanobacterial genomes, we performed a comprehensive comparative analysis of PRXs and explored their diversity, distribution, domain structure and evolution. Results Overall 244 putative prx genes were identified, which were abundant in filamentous diazotrophic cyanobacteria, Acaryochloris marina MBIC 11017, and unicellular cyanobacteria inhabiting freshwater and hot-springs, while poor in all Prochlorococcus and marine Synechococcus strains. Among these putative genes, 25 open reading frames (ORFs) encoding hypothetical proteins were identified as prx gene family members and the others were already annotated as prx genes. All 244 putative PRXs were classified into five major subfamilies (1-Cys, 2-Cys, BCP, PRX5_like, and PRX-like) according to their domain structures. The catalytic motifs of the cyanobacterial PRXs were similar to those of eukaryotic PRXs and highly conserved in all but the PRX-like subfamily. Classical motif (CXXC) of thioredoxin was detected in protein sequences from the PRX-like subfamily. Phylogenetic tree constructed of catalytic domains coincided well with the domain structures of PRXs and the phylogenies based on 16s rRNA. Conclusions The distribution of genes encoding PRXs in different unicellular and filamentous cyanobacteria especially those sub-families like PRX-like or 1-Cys PRX correlate with the genome size, eco-physiology, and physiological properties of the organisms. Cyanobacterial and eukaryotic PRXs share similar conserved motifs, indicating that cyanobacteria adopt similar catalytic mechanisms as eukaryotes. All cyanobacterial PRX proteins share highly similar structures, implying that these genes may originate from a common ancestor. In this study, a general framework of the sequence-structure-function connections of the PRXs was revealed, which may facilitate functional investigations of PRXs in various organisms.</p
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