scholarly journals Endogenously Synthesized (−)-proto-Quercitol and Glycine Betaine Are Principal Compatible Solutes of Schizochytrium sp. Strain S8 (ATCC 20889) and Three New Isolates of Phylogenetically Related Thraustochytrids

2007 ◽  
Vol 73 (18) ◽  
pp. 5848-5856 ◽  
Author(s):  
Anita N. Jakobsen ◽  
Inga M. Aasen ◽  
Arne R. Strøm
Keyword(s):  
Glycine Betaine ◽  
Optical Rotation ◽  
Compatible Solutes ◽  
Docosapentaenoic Acid ◽  
Dry Weight ◽  
Defined Medium ◽  
18S Rrna Gene ◽  
Resonance Spectroscopy ◽  
Rrna Gene ◽  
Specific Optical Rotation

ABSTRACT We report that endogenously synthesized (−)-proto-quercitol (1d-1,3,4/2,5-cyclohexanepentol) and glycine betaine were the principal compatible solutes of Schizochytrium sp. strain S8 (ATCC 20889) and three new osmotolerant isolates of thraustochytrids (strains T65, T66, and T67). The compatible solutes were identified and quantified by use of nuclear magnetic resonance spectroscopy, and their identity was confirmed by mass spectroscopy and measurement of the specific optical rotation. The cellular content of compatible solutes increased with increasing NaCl concentration of a defined medium. (−)-proto-Quercitol was the dominating solute at all NaCl concentrations tested (0.25 to 1.0 M), e.g., cells of S8 and T66 stressed with 1.0 M NaCl accumulated about 500 μmol (−)-proto-quercitol and 100 μmol glycine betaine per g dry weight. To our knowledge, (−)-proto-quercitol has previously been found only in eucalyptus. The 18S rRNA gene sequences of the four (−)-proto-quercitol-producing strains showed 99% identity, and they displayed the same fatty acid profile. The only polyunsaturated fatty acids accumulated were docosahexaenoic acid (78%) and docosapentaenoic acid (22%). A less osmotolerant isolate (strain T29), which was closely phylogenetically related to Thraustochytrium aureum (ATCC 34304), did not contain (−)-proto-quercitol or glycine betaine. Thus, the level of osmotolerance and the osmolyte systems vary among thraustochytrids.

scholarly journals Glycine Betaine, Carnitine, and Choline Enhance Salinity Tolerance and Prevent the Accumulation of Sodium to a Level Inhibiting Growth of Tetragenococcus halophila

2000 ◽  
Vol 66 (2) ◽  
pp. 509-517 ◽  
Author(s):  
Hervé Robert ◽  
Claire Le Marrec ◽  
Carlos Blanco ◽  
Mohamed Jebbar
Keyword(s):  
Glycine Betaine ◽  
High Salinity ◽  
De Novo ◽  
Compatible Solutes ◽  
Dry Weight ◽  
Defined Medium ◽  
Intracellular Sodium ◽  
Growth Media ◽  
Solute Content ◽  
Moderately Halophilic Bacterium

ABSTRACT Natural-abundance 13C-nuclear magnetic resonance was used to probe the intracellular organic solute content of the moderately halophilic bacterium Tetragenococcus halophila. When grown in complex growth media supplemented or not with NaCl,T. halophila accumulates glycine betaine and carnitine. Unlike other moderate halophiles, T. halophila was not able to produce potent osmoprotectants (such as ectoines and glycine betaine) through de novo synthesis when cultured in defined medium under hyperosmotic constraint. Addition of 2 mM carnitine, glycine betaine, or choline to defined medium improved growth parameters, not only at high salinity (up to 2.5 M NaCl) but also in media lacking NaCl. These compounds were taken up when available in the surrounding medium. The transport activity occurred at low and high salinities and seems to be constitutive. Glycine betaine and carnitine were accumulated by T. halophila in an unmodified form, while exogenously provided choline led to an intracellular accumulation of glycine betaine. This is the first evidence of the existence of a choline-glycine betaine pathway in a lactic acid bacterium. An assay showed that the compatible solutes strikingly repressed the accumulation of glutamate and slightly increased the intracellular potassium level only at high salinity. Interestingly, osmoprotectant-treated cells were able to maintain the intracellular sodium concentration at a relatively constant level (200 to 300 nmol/mg [dry weight]), independent of the NaCl concentration of the medium. In contrast, in the absence of osmoprotectant, the intracellular sodium content increased sharply from 200 to 2,060 nmol/mg (dry weight) when the salinity of the medium was raised from 1 to 2 M. Indeed, the imported compatible solutes play an actual role in regulating the intracellular Na+ content and confer a much higher salt tolerance to T. halophila.

scholarly journals Biochemical parameters and 18S rRNA gene sequence analysis amongst green microalgal strains from selected aquatic sites of Eastern India

2020 ◽  
Vol 82 (6) ◽  
pp. 1205-1216
Author(s):  
Rashi Vishwakarma ◽  
Dolly Wattal Dhar ◽  
Mrutyunjay Jena ◽  
Madhulika Shukla
Keyword(s):  
18S Rrna ◽  
Reference Strain ◽  
Biochemical Characterization ◽  
Compositional Analysis ◽  
Dry Weight ◽  
18S Rrna Gene ◽  
Soluble Proteins ◽  
Rrna Gene ◽  
Chlorella Sp ◽  
Gene Sequence Analysis

Abstract In the present study, 24 green microalgae strains were isolated from selected aquatic sites of India. These were microscopically identified as Chlamydomonas sp., Scenedesmus sp., Chlorella sp., Dictyosphaerium sp. and Dunaliella sp. Nannochloropsis sp. (MCC 25), was used as a reference strain. Results showed that Dictyosphaerium sp. (MCC 10 and MCC 12) showed relatively higher nutritive content. The total soluble proteins in the reference strain was 21.4%, whereas it showed carbohydrate content of 17.2% and the lipids were 3.4% on a dry weight basis. Best performing strains were identified by biochemical characterization. Five genera were selected for molecular identification since they were the most representative based upon their area of isolation and their optimum content of total soluble proteins, carbohydrates and lipids. 18S rRNA sequencing authenticated their identification as Scenedesmus sp., Dictyosphaerium sp. and Chlorella sp. The sequences of these have been submitted in NCBI database with accession numbers as KT808247–KT808251. The correlation matrix showed positive correlation between carbohydrates and lipids, while negative correlation was seen between proteins and carbohydrates and between proteins and lipids. This study emphasizes the need for complete compositional analysis of the biomass for the possible applicability in the area of value addition.

ISOLATION AND CHARACTERIZATION POLYHYDROBUTYRATE (PHB) PRODUCING BACTERIA FROM WASTE COOKING OIL USING POMEGRANATE MOLASSES AS CARBON SOURCE

2015 ◽  
Vol 77 (31) ◽  
Author(s):  
Laila Muftah Zargoun ◽  
Nor Azimah Mohd Zain ◽  
Shafinaz Shahir
Keyword(s):  
Carbon Source ◽  
Nile Blue ◽  
Dry Weight ◽  
Waste Cooking Oil ◽  
Biochemical Properties ◽  
Resonance Spectroscopy ◽  
Rrna Gene ◽  
Cooking Oil ◽  
Sudan Black B ◽  
Isolation And Characterization

In this study, a polyhydroxybutyrate (PHB) producing bacterium was isolated from waste cooking oil and characterized for its morphological and biochemical properties. Staining methods utilizing Sudan Black B and Nile Blue A were used on isolated bacterium to demonstrate good capability for synthesizing PHB. It was shown that the isolated bacterium species was related to Bacillus thuringiensis LMA by using 16S rRNA gene sequences analysis. During the stationary phase, the Bacillus strain was subjected to 10 % (w/v) of pomegranate molasses as a carbon source and 5 g/L of peptone as a nitrogen source. 2 ml of batch fermentation was collected. Samples were collected twice during the incubation period for detection of PHB using Sudan Black B. The PHB production accounted for up to 57.45% of the cell dry weight. The PHB produced was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Spectroscopy (NMR). The drastic absorption band at approximately 1717 cm-1 indicated the stretching vibration of C=O group in PHB polyester, while the functional groups of PHB were identified methyl (-CH3) at 1.28 ppm, methylene (-CH2) 2.0 and 2.5 ppm, and methylene doublet group (CH3) at 5.3 ppm.

scholarly journals Role of the Glycine Betaine and Carnitine Transporters in Adaptation of Listeria monocytogenes to Chill Stress in Defined Medium

2003 ◽  
Vol 69 (12) ◽  
pp. 7492-7498 ◽  
Author(s):  
Apostolos S. Angelidis ◽  
Gary M. Smith
Keyword(s):  
Listeria Monocytogenes ◽  
Cold Stress ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
Growth Stimulation ◽  
Defined Medium ◽  
Small Degree ◽  
Compatible Solute ◽  
Triple Mutant ◽  
Carnitine Transport

ABSTRACT The food-borne pathogen Listeria monocytogenes proliferates at refrigeration temperatures, rendering refrigeration ineffective in the preservation of Listeria-contaminated foods. The uptake and intracellular accumulation of the potent compatible solutes glycine betaine and carnitine has been shown to be a key mediator of the pathogen's cold-tolerant phenotype. To date, three compatible solute systems are known to operate in L. monocytogenes: glycine betaine porter I (BetL), glycine betaine porter II (Gbu), and the carnitine transporter OpuC. We investigated the specificity of each transporter towards each compatible solute at 4°C by examining mutant derivatives of L. monocytogenes 10403S that possess each of the transporters in isolation. Kinetic and steady-state compatible solute accumulation data together with growth rate experiments demonstrated that under cold stress glycine betaine transport is primarily mediated by Gbu and that Gbu-mediated betaine uptake results in significant growth stimulation of chill-stressed cells. BetL and OpuC can serve as minor porters for the uptake of betaine, and their action is capable of providing a small degree of cryotolerance. Under cold stress, carnitine transport occurs primarily through OpuC and results in a high level of cryoprotection. Weak carnitine transport occurs via Gbu and BetL, conferring correspondingly weak cryoprotection. No other transporter in L. monocytogenes 10403S appears to be involved in transport of either compatible solute at 4°C, since a triple mutant strain yielded neither transport nor accumulation of glycine betaine or carnitine and could not be rescued by either osmolyte when grown at that temperature.

scholarly journals Identification of OpuC as a Chill-Activated and Osmotically Activated Carnitine Transporter in Listeria monocytogenes

2002 ◽  
Vol 68 (6) ◽  
pp. 2644-2650 ◽  
Author(s):  
Apostolos S. Angelidis ◽  
Linda Tombras Smith ◽  
Les M. Hoffman ◽  
Gary M. Smith
Keyword(s):  
Listeria Monocytogenes ◽  
Glycine Betaine ◽  
Low Temperatures ◽  
Direct Sequencing ◽  
Compatible Solutes ◽  
Hyperosmotic Stress ◽  
Resonance Spectroscopy ◽  
Carnitine Transporter ◽  
Food Borne ◽  
Carnitine Transport

ABSTRACT The food-borne pathogen Listeria monocytogenes is notable for its ability to grow under osmotic stress and at low temperatures. It is known to accumulate the compatible solutes glycine betaine and carnitine from the medium in response to osmotic or chill stress, and this accumulation confers tolerance to these stresses. Two permeases that transport glycine betaine have been identified, both of which are activated by hyperosmotic stress and one of which is activated by low temperature. An osmotically activated transporter for carnitine, OpuC, has also been identified. We have isolated a Tn917-LTV3 insertional mutant that could not be rescued from hyperosmotic stress by exogenous carnitine. The mutant, LTS4a, grew indistinguishably from a control strain (DP-L1044) in the absence of stress or in the absence of carnitine, but DP-L1044 grew substantially faster under osmotic or chill stress in the presence of carnitine. LTS4a was found to be strongly impaired in KCl-activated as well as chill-activated carnitine transport. 13C nuclear magnetic resonance spectroscopy of perchloric acid extracts showed that accumulation of carnitine by LTS4a was negligible under all conditions tested. Direct sequencing of LTS4a genomic DNA with a primer based on Tn917-LTV3 yielded a 487-bp sequence, which allowed us to determine that the opuC operon had been interrupted by the transposon. It can be concluded that opuC encodes a carnitine transporter that can be activated by either hyperosmotic stress or chill and that the transport system plays a significant role in the tolerance of L. monocytogenes to both forms of environmental stress.

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

scholarly journals Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Claire Y. T. Wang ◽  
Emma L. Ballard ◽  
Zuleima Pava ◽  
Louise Marquart ◽  
Jane Gaydon ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Plasmodium Falciparum ◽  
18S Rrna ◽  
Drug Efficacy ◽  
18S Rrna Gene ◽  
Molecular Techniques ◽  
Qpcr Assay ◽  
Rrna Gene ◽  
Analytical Sensitivity ◽  
Blood Samples

Abstract Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials.

scholarly journals 16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

Polar Biology ◽  
2021 ◽  
Author(s):  
Eleanor E. Jackson ◽  
Ian Hawes ◽  
Anne D. Jungblut
Keyword(s):  
16S Rrna ◽  
18S Rrna ◽  
High Throughput Sequencing ◽  
Microbial Mats ◽  
Gene Diversity ◽  
Salinity Gradient ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Ice Shelf ◽  
The Impact

AbstractThe undulating ice of the McMurdo Ice Shelf, Southern Victoria Land, supports one of the largest networks of ice-based, multiyear meltwater pond habitats in Antarctica, where microbial mats are abundant and contribute most of the biomass and biodiversity. We used 16S rRNA and 18S rRNA gene high-throughput sequencing to compare variance of the community structure in microbial mats within and between ponds with different salinities and pH. Proteobacteria and Cyanobacteria were the most abundant phyla, and composition at OTU level was highly specific for the meltwater ponds with strong community sorting along the salinity gradient. Our study provides the first detailed evaluation of eukaryote communities for the McMurdo Ice Shelf using the 18S rRNA gene. They were dominated by Ochrophyta, Chlorophyta and Ciliophora, consistent with previous microscopic analyses, but many OTUs belonging to less well-described heterotrophic protists from Antarctic ice shelves were also identified including Amoebozoa, Rhizaria and Labyrinthulea. Comparison of 16S and 18S rRNA gene communities showed that the Eukaryotes had lower richness and greater similarity between ponds in comparison with Bacteria and Archaea communities on the McMurdo Ice shelf. While there was a weak correlation between community dissimilarity and geographic distance, the congruity of microbial assemblages within ponds, especially for Bacteria and Archaea, implies strong habitat filtering in ice shelf meltwater pond ecosystems, especially due to salinity. These findings help to understand processes that are important in sustaining biodiversity and the impact of climate change on ice-based aquatic habitats in Antarctica.

scholarly journals 18S rRNA gene sequences of leptocephalus gut contents, particulate organic matter, and biological oceanographic conditions in the western North Pacific

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsuyoshi Watanabe ◽  
Satoshi Nagai ◽  
Yoko Kawakami ◽  
Taiga Asakura ◽  
Jun Kikuchi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
North Pacific ◽  
Western North Pacific ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Gut Contents ◽  
Rrna Gene ◽  
Marine Snow ◽  
Chlorophyll Maximum

AbstractEel larvae apparently feed on marine snow, but many aspects of their feeding ecology remain unknown. The eukaryotic 18S rRNA gene sequence compositions in the gut contents of four taxa of anguilliform eel larvae were compared with the sequence compositions of vertically sampled seawater particulate organic matter (POM) in the oligotrophic western North Pacific Ocean. Both gut contents and POM were mainly composed of dinoflagellates as well as other phytoplankton (cryptophytes and diatoms) and zooplankton (ciliophoran and copepod) sequences. Gut contents also contained cryptophyte and ciliophoran genera and a few other taxa. Dinoflagellates (family Gymnodiniaceae) may be an important food source and these phytoplankton were predominant in gut contents and POM as evidenced by DNA analysis and phytoplankton cell counting. The compositions of the gut contents were not specific to the species of eel larvae or the different sampling areas, and they were most similar to POM at the chlorophyll maximum in the upper part of the thermocline (mean depth: 112 m). Our results are consistent with eel larvae feeding on marine snow at a low trophic level, and feeding may frequently occur in the chlorophyll maximum in the western North Pacific.

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