scholarly journals Identification of Virulence Determinants for Endocarditis in Streptococcus sanguinis by Signature-Tagged Mutagenesis

2005 ◽  
Vol 73 (9) ◽  
pp. 6064-6074 ◽  
Author(s):  
Sehmi Paik ◽  
Lauren Senty ◽  
Sankar Das ◽  
Jody C. Noe ◽  
Cindy L. Munro ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Virulence Factors ◽  
Ribonucleotide Reductase ◽  
Large Scale ◽  
Broth Culture ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Streptococcus Sanguinis ◽  
Competitive Index ◽  
Homoserine Kinase

ABSTRACT Streptococcus sanguinis is a gram-positive, facultative anaerobe and a normal inhabitant of the human oral cavity. It is also one of the most common agents of infective endocarditis, a serious endovascular infection. To identify virulence factors for infective endocarditis, signature-tagged mutagenesis (STM) was applied to the SK36 strain of S. sanguinis, whose genome is being sequenced. STM allows the large-scale creation, in vivo screening, and recovery of a series of mutants with altered virulence. Screening of 800 mutants by STM identified 38 putative avirulent and 5 putative hypervirulent mutants. Subsequent molecular analysis of a subset of these mutants identified genes encoding undecaprenol kinase, homoserine kinase, anaerobic ribonucleotide reductase, adenylosuccinate lyase, and a hypothetical protein. Virulence reductions ranging from 2-to 150-fold were confirmed by competitive index assays. One putatively hypervirulent strain with a transposon insertion in an intergenic region was identified, though increased virulence was not confirmed in competitive index assays. All mutants grew comparably to SK36 in aerobic broth culture except for the homoserine kinase mutant. Growth of this mutant was restored by the addition of threonine to the medium. Mutants containing an insertion or in-frame deletion in the anaerobic ribonucleotide reductase gene failed to grow under strictly anaerobic conditions. The results suggest that housekeeping functions such as cell wall synthesis, amino acid and nucleic acid synthesis, and the ability to survive under anaerobic conditions are important virulence factors in S. sanguinis endocarditis.

scholarly journals Association of Novel Streptococcus sanguinis Virulence Factors With Pathogenesis in a Native Valve Infective Endocarditis Model

2020 ◽  
Vol 11 ◽  
Author(s):  
Anthony M. Martini ◽  
Bridget S. Moricz ◽  
Allison K. Ripperger ◽  
Phuong M. Tran ◽  
Molly E. Sharp ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Virulence Factors ◽  
Native Valve ◽  
Streptococcus Sanguinis

scholarly journals Novel Methods Using an Arthrobacter sp. to Create Anaerobic Conditions for Biobutanol Production from Sweet Sorghum Juice by Clostridium beijerinckii

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 178
Author(s):  
Chalida Daengbussadee ◽  
Lakkana Laopaiboon ◽  
Anuphon Kaewmaneewat ◽  
Likit Sirisantimethakom ◽  
Pattana Laopaiboon
Keyword(s):  
Sweet Sorghum ◽  
Large Scale ◽  
Clostridium Beijerinckii ◽  
Control Treatment ◽  
Strictly Aerobic ◽  
Strictly Anaerobic ◽  
Aerobic Bacterium ◽  
Butanol Production ◽  
Anaerobic Conditions ◽  
Sweet Sorghum Juice

Biobutanol can be produced by Clostridia via an acetone–butanol–ethanol (ABE) fermentation under strictly anaerobic conditions. Oxygen-free nitrogen (OFN) gas is typically used to create anaerobic conditions for ABE fermentations. However, this method is not appropriate for large-scale fermentations as it is quite costly. The aim of this work was to study the feasibility of butanol production from sweet sorghum juice (SSJ) by Clostridium beijerinckii TISTR 1461 using various methods to create anaerobic conditions, i.e., growth of a strictly aerobic bacterium, an Arthrobacter sp., under different conditions and a chemical method using sodium dithionite (SDTN) to consume residual oxygen. SSJ containing 60 g/L of total sugar supplemented with 1.27 g/L of (NH4)2SO4 was used as a substrate for butanol production. The results showed that 0.25 mM SDTN could create anaerobic conditions, but in this case, C.beijerinckii TISTR 1461 could produce butanol at a concentration (PB) of only 8.51 g/L with a butanol productivity (QB) of 0.10 g/L·h. Arthrobacter sp. BCC 72131 could also be used to create anaerobic conditions. Mixed cultures of C.beijerinckii TISTR 1461 and Arthrobacter sp. BCC 72131 created anaerobic conditions by inoculating the C.beijerinckii 4 h after Arthrobacter. This gave a PB of 10.39 g/L with a QB of 0.20 g/L·h. Comparing butanol production with the control treatment (using OFN gas to create anaerobic conditions, yielding a PB of 9.88 g/L and QB of 0.21 g/L·h) indicated that using Arthrobacter sp. BCC 72131 was an appropriate procedure for creating anaerobic conditions for high levels of butanol production by C. beijerinckii TISTR 1461 from a SSJ medium.

Deoxyribonucleotide Synthesis in an Escherichia coli Mutant (H 1491) which Lacks Ribonucleotide Reductase Subunit B2

1989 ◽  
Vol 44 (7-8) ◽  
pp. 715-718 ◽  
Author(s):  
Jens Harder ◽  
Hartmut Follmann ◽  
Klaus Hantke
Keyword(s):  
Escherichia Coli ◽  
Dna Synthesis ◽  
Ribonucleotide Reductase ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Sensitive Mutant ◽  
E Coli ◽  
Key Enzyme ◽  
Minimal Media

An iron-sensitive mutant of E. coli with a Mudl phage insertion in the nrdB gene lacks subunit B2 of the key enzyme of DNA synthesis, ribonucleotide reductase. Nevertheless, these cells are capable of growing in minimal media under anaerobic conditions, indicating a second enzyme or pathway for deoxyribonucleotide synthesis. We here show that ribonucleotide reduction cannot be unambiguously measured in bacterial extracts whereas phosphorylase- catalyzed deoxyribosyl transfer does occur; however these salvage reactions could not function in vivo in the absence of deoxyribosides. It is suggested that the cells possess a specific, anaerobic ribonucleotide reductase which escapes detection under aerobic standard conditions, similar to the situation found in strictly anaerobic methanogens.

Versatile Cryostated Optically Transparent Thin-Layer Electrochemical (OTTLE) Cell for Variable-Temperature UV-Vis/IR Spectroelectrochemical Studies

1994 ◽  
Vol 48 (12) ◽  
pp. 1522-1528 ◽  
Author(s):  
F. Hartl ◽  
H. Luyten ◽  
H. A. Nieuwenhuis ◽  
G. C. Schoemaker
Keyword(s):  
Thin Layer ◽  
Low Temperatures ◽  
Variable Temperature ◽  
Experimental Setup ◽  
Strictly Anaerobic ◽  
Carbonyl Complexes ◽  
Anaerobic Conditions ◽  
Optically Transparent ◽  
Solution Layer ◽  
Preset Temperature

This article describes the construction of a novel optically transparent thin-layer electrochemical (OTTLE) cell for IR and UV-Vis spectroelectrochemical experiments at variable temperature. The cell has a three-electrode set melt-sealed into a smooth polyethylene spacer which is sandwiched between two CaF2 windows. The width of this spacer (0.18–0.20 mm) defines the thickness of the thin solution layer. The whole electrode assembly is housed in a thermostated Cu block of the OTTLE cell which fits into a double-walled nitrogen-bath cryostat. The experimental setup permits relatively fast electrolysis within the tested temperature range of 295 to 173 K under strictly anaerobic conditions and protection of light-sensitive compounds. Other important merits of the cell design include lack of leakage, facile cleaning, almost negligible variation of the preset temperature, and facile manipulation in the course of the experiments. The applicability of the variable-temperature IR/UV-Vis OTTLE cell is demonstrated by stabilization of a few electrogenerated carbonyl complexes of Mn(I) and Ru(II) with 3,5-di- tert. butyl-1,2-benzo(semi)quinone (DB(S)Q) and N, N′-diisopropyl-1,4-diaza-1,3-butadiene (iPr-DAB) ligands, respectively, at appropriately low temperatures.

scholarly journals Redesigning Escherichia coli Metabolism for Anaerobic Production of Isobutanol

2011 ◽  
Vol 77 (14) ◽  
pp. 4894-4904 ◽  
Author(s):  
Cong T. Trinh ◽  
Johnny Li ◽  
Harvey W. Blanch ◽  
Douglas S. Clark
Keyword(s):  
Escherichia Coli ◽  
Anaerobic Growth ◽  
Mode Analysis ◽  
Glycolytic Flux ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Content Type ◽  
E Coli ◽  
Model Predictions ◽  
Chromosomal Genes

ABSTRACTFermentation enables the production of reduced metabolites, such as the biofuels ethanol and butanol, from fermentable sugars. This work demonstrates a general approach for designing and constructing a production host that uses a heterologous pathway as an obligately fermentative pathway to produce reduced metabolites, specifically, the biofuel isobutanol. Elementary mode analysis was applied to design anEscherichia colistrain optimized for isobutanol production under strictly anaerobic conditions. The central metabolism ofE. coliwas decomposed into 38,219 functional, unique, and elementary modes (EMs). The model predictions revealed that during anaerobic growthE. colicannot produce isobutanol as the sole fermentative product. By deleting 7 chromosomal genes, the total 38,219 EMs were constrained to 12 EMs, 6 of which can produce high yields of isobutanol in a range from 0.29 to 0.41 g isobutanol/g glucose under anaerobic conditions. The remaining 6 EMs rely primarily on the pyruvate dehydrogenase enzyme complex (PDHC) and are typically inhibited under anaerobic conditions. The redesignedE. colistrain was constrained to employ the anaerobic isobutanol pathways through deletion of 7 chromosomal genes, addition of 2 heterologous genes, and overexpression of 5 genes. Here we present the design, construction, and characterization of an isobutanol-producingE. colistrain to illustrate the approach. The model predictions are evaluated in relation to experimental data and strategies proposed to improve anaerobic isobutanol production. We also show that the endogenous alcohol/aldehyde dehydrogenase AdhE is the key enzyme responsible for the production of isobutanol and ethanol under anaerobic conditions. The glycolytic flux can be controlled to regulate the ratio of isobutanol to ethanol production.

Histochemical Demonstration of Certain DPN-Linked Dehydrogenases and of Aldolase in the Red and White Fibres of Pigeon Breast-Muscle

1962 ◽  
Vol s3-103 (61) ◽  
pp. 41-46
Author(s):  
J. C. GEORGE ◽  
C. L. TALESARA
Keyword(s):  
Enzyme Activity ◽  
Histochemical Demonstration ◽  
Breast Muscle ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
High Concentration ◽  
Hydrogen Acceptor ◽  
Localization Pattern ◽  
Important Link

The distribution and localization-pattern of certain DPN-linked dehydrogenases (malic, lactic, D-glucose, glutamic, and a-glycerophosphate) were demonstrated histochemically in the red and white fibres of pigeon breast-muscle by using neotetrazolium as the hydrogen acceptor, under strictly anaerobic conditions. All the dehydrogenases studied showed distinctly higher enzyme activity in the narrow red fibres than in the broad white fibres. That of a-glycerophosphate was, however, found to be appreciably more abundant than other dehydrogenases in the broad fibres. A high concentration of aldolase, which forms an important link in the chain of enzymes in glycolysis, was histochemically demonstrated in the broad, white, glycogen-loaded fibres.

scholarly journals Postcaesarean open-heart surgery for Streptococcus sanguinis infective endocarditis

2013 ◽  
Vol 2013 (nov14 1) ◽  
pp. bcr2013010103-bcr2013010103 ◽  
Author(s):  
K. Kongwattanakul ◽  
S. Tribuddharat ◽  
S. Prathanee ◽  
O. Pachirat
Keyword(s):  
Infective Endocarditis ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Open Heart ◽  
Streptococcus Sanguinis

scholarly journals Myothermic apparatus

1928 ◽  
Vol 103 (723) ◽  
pp. 117-137 ◽  
Keyword(s):  
Heat Production ◽  
Present Author ◽  
Single Stimulus ◽  
Relative Accuracy ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Essential Condition ◽  
Energy Exchanges

The investigation to be described in subsequent papers represent an attempt to clear up, with the greatest accuracy possible, a number of outstanding or controversial points in connection with the energy exchanges of muscle. During the course of them a new and striking phenomenon has been encountered, in respect of the resting heat-production of muscles kept under strictly anaerobic conditions. It has been necessary, moreover, for various purposes, to follow the heat-production of stimulated or recovering muscles for long periods, sometimes for an hour or more. The apparatus available proved inadequate for these new purposes, and had to be designed and constructed afresh. The present paper is a description of the methods finally adopted; the results obtained are given separately. In almost every respect the apparatus now employed will yield more reliable results, and is simpler to use, than any previously described, at any rate by the present author. The essential condition which it fulfils is that it will read, with relative accuracy, not only the heat suddenly produced by a single stimulus, but that liberated over long intervals at rest, or in recovery, or by prolonged discontinuous stimulation.

Influence du mode de culture dans la toxinogénèse de Plectridium tetani

1970 ◽  
Vol 16 (2) ◽  
pp. 135-136 ◽  
Author(s):  
G. Vinet ◽  
V. Fredette
Keyword(s):  
Tetanus Toxin ◽  
Culture Medium ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions

Production of tetanus toxin under strictly anaerobic conditions does not favor high titers comparable to those obtained when the surface of the culture medium is largely exposed to the air.

scholarly journals Coexistence of Antibiotic Resistance Genes and Virulence Factors Deciphered by Large-Scale Complete Genome Analysis

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Yu Pan ◽  
Jiaxiong Zeng ◽  
Liguan Li ◽  
Jintao Yang ◽  
Ziyun Tang ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Virulence Factors ◽  
Resistance Genes ◽  
Large Scale ◽  
Antibiotic Resistance Genes ◽  
Comprehensive Analysis ◽  
Health Concern ◽  
Human Pathogens ◽  
Bacterial Genomes ◽  
Gene Acquisition

ABSTRACT Widespread use of antibiotics has enhanced the evolution of highly resilient pathogens and poses a severe risk to human health via coselection of antibiotic resistance genes (ARGs) and virulence factors (VFs). In this study, we rigorously evaluate the abundance relationship and physical linkage between ARGs and VFs by performing a comprehensive analysis of 9,070 bacterial genomes isolated from multiple species and hosts. The coexistence of ARGs and VFs was observed in bacteria across distinct phyla, pathogenicities, and habitats, especially among human-associated pathogens. The coexistence patterns of gene elements in different habitats and pathogenicity groups were similar, presumably due to frequent gene transfer. A shorter intergenic distance between mobile genetic elements and ARGs/VFs was detected in human/animal-associated bacteria, indicating a higher transfer potential. Increased accumulation of exogenous ARGs/VFs in human pathogens highlights the importance of gene acquisition in the evolution of human commensal bacteria. Overall, the findings provide insights into the genic features of combinations of ARG-VF and expand our understanding of ARG-VF coexistence in bacteria. IMPORTANCE Antibiotic resistance has become a serious global health concern. Despite numerous case studies, a comprehensive analysis of ARG and VF coexistence in bacteria is lacking. In this study, we explore the coexistence profiles of ARGs and VFs in diverse categories of bacteria by using a high-resolution bioinformatics approach. We also provide compelling evidence of unique ARG-VF gene pairs coexisting in specific bacterial genomes and reveal the potential risk associated with the coexistence of ARGs and VFs in organisms in both clinical settings and environments.

Sign in / Sign up

Export Citation Format

Share Document