scholarly journals Bacterial Consumption of T4 Phages

2021 ◽  
Vol 9 (9) ◽  
pp. 1852
Author(s):  
Jean-Jacques Godon ◽  
Ariane Bize ◽  
Hoang Ngo ◽  
Laurent Cauquil ◽  
Mathieu Almeida ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Bacterial Species ◽  
Wastewater Sludge ◽  
Nitrogen And Phosphorus ◽  
Bacterial Dna ◽  
Starting Point ◽  
T4 Phage

The bacterial consumption of viruses not been reported on as of yet even though bacteria feed on almost anything. Viruses are widely distributed but have no acknowledged active biocontrol. Viral biomass undoubtedly reintegrates trophic cycles; however, the mechanisms of this phase still remain unknown. 13C-labelled T4 phages monitor the increase of the density of the bacterial DNA concomitant with the decrease of plaque forming units. We used 12C T4 phages as a control. T4 phage disappearance in wastewater sludge was found to occur mainly through predation by Aeromonadacea. Phage consumption also favours significant in situ bacterial growth. Furthermore, an isolated strain of Aeromonas was observed to grow on T4 phages as sole the source of carbon, nitrogen, and phosphorus. Bacterial species are capable of consuming bacteriophages in situ, which is likely a widespread and underestimated type of biocontrol. This assay is anticipated as a starting point for harnessing the bacterial potential in limiting the diffusion of harmful viruses within environments such as in the gut or in water.

scholarly journals Bacterial Predation on T4 Phages

2021 ◽  
Author(s):  
jean-jacques godon ◽  
ariane bize ◽  
hoang ngo ◽  
laurent cauquil ◽  
mathieu almeida ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Bacterial Species ◽  
Sole Source ◽  
Stable Isotope Probing ◽  
Wastewater Sludge ◽  
Nitrogen And Phosphorus ◽  
Bacterial Dna ◽  
Starting Point ◽  
T4 Phage

Abstract Background: Bacterial consumption of viruses has never yet been reported, even though bacteria feed on almost anything. Viruses are omnipresent predators for all organisms, but have no acknowledged active biocontrol. The viral biomass undoubtedly reintegrates the trophic cycles, however the mechanisms of this phase still remain unknown.Methods: Here, we used stable isotope probing with 13C labelled T4 phages to monitor the increase of density of the bacterial DNA concomitant with the decrease of plaque forming units. We used 12C T4 phages as control.Results: T4 phage disappearance in wastewater sludge was found to occur mainly through predation by Aeromonadacea. Phage consumption also favours significant in situ bacterial growth. Furthermore, an isolated strain of Aeromonas was observed to grow on T4 phages as sole source of carbon, nitrogen and phosphorus.Conclusions: bacterial species are capable of consuming bacteriophages in situ, which is likely a widespread and underestimated type of biocontrol. This assay is anticipated as a starting point for harnessing the bacterial potential in limiting the diffusion of harmful viruses within environments such as gut or water.

scholarly journals Bacterial predation on T4 phages

2021 ◽  
Author(s):  
jean-jacques godon ◽  
ariane bize ◽  
hoang ngo ◽  
laurent cauquil ◽  
mathieu almeida ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Bacterial Species ◽  
Sole Source ◽  
Stable Isotope Probing ◽  
Wastewater Sludge ◽  
Nitrogen And Phosphorus ◽  
E Coli ◽  
Starting Point ◽  
T4 Phage

Bacterial consumption of viruses has never yet been reported, even though bacteria feed on almost anything. Viruses are omnipresent predators for all organisms, but have no acknowledged active biocontrol. The viral biomass undoubtedly reintegrates the trophic cycles, however the mechanisms of this phase still remain unknown. Here, we show that an E. coli infecting virus - the coliphage T4- was actively consumed by bacteria. Using stable isotope probing with 13C labelled T4 phages, T4 phage disappearance in wastewater sludge was found to occur mainly through predation by Aeromonadacea. Phage consumption also favours significant in situ bacterial growth. Furthermore, an isolated strain of Aeromonas was observed to grow on T4 phages as sole source of carbon, nitrogen and phosphorus. Results demonstrate how bacterial species are capable of consuming bacteriophages in situ, which is likely a widespread and underestimated type of biocontrol. This assay is anticipated as a starting point for harnessing the bacterial potential in limiting the diffusion of harmful viruses within environments such as gut or water.

scholarly journals Chemical Modification as a Method of Improving Biocompatibility of Carbon Nonwovens

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3198
Author(s):  
Justyna Frączyk ◽  
Sylwia Magdziarz ◽  
Ewa Stodolak-Zych ◽  
Ewa Dzierzkowska ◽  
Dorota Puchowicz ◽  
...  
Keyword(s):  
Surface Modification ◽  
Cellular Response ◽  
Fiber Surface ◽  
Thermal Conversion ◽  
Cartilage Tissue ◽  
Polar Component ◽  
Nonwoven Fabrics ◽  
Biological Compatibility ◽  
Starting Point

It was shown that carbon nonwoven fabrics obtained from polyacrylonitrile fibers (PAN) by thermal conversion may be modified on the surface in order to improve their biological compatibility and cellular response, which is particularly important in the regeneration of bone or cartilage tissue. Surface functionalization of carbon nonwovens containing C–C double bonds was carried out using in situ generated diazonium salts derived from aromatic amines containing both electron-acceptor and electron-donor substituents. It was shown that the modification method characteristic for materials containing aromatic structures may be successfully applied to the functionalization of carbon materials. The effectiveness of the surface modification of carbon nonwoven fabrics was confirmed by the FTIR method using an ATR device. The proposed approach allows the incorporation of various functional groups on the nonwovens’ surface, which affects the morphology of fibers as well as their physicochemical properties (wettability). The introduction of a carboxyl group on the surface of nonwoven fabrics, in a reaction with 4-aminobenzoic acid, became a starting point for further modifications necessary for the attachment of RGD-type peptides facilitating cell adhesion to the surface of materials. The surface modification reduced the wettability (θ) of the carbon nonwoven by about 50%. The surface free energy (SFE) in the chemically modified and reference nonwovens remained similar, with the surface modification causing an increase in the polar component (ɣp). The modification of the fiber surface was heterogeneous in nature; however, it provided an attractive site of cell–materials interaction by contacting them to the fiber surface, which supports the adhesion process.

scholarly journals Rapid Identification of Bacterial Species with Bacterial DNA Microarray in Cirrhotic Patients with Spontaneous Bacterial Peritonitis

2009 ◽  
Vol 48 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Takaaki Sugihara ◽  
Masahiko Koda ◽  
Yoshiko Maeda ◽  
Tomomitsu Matono ◽  
Takakazu Nagahara ◽  
...  
Keyword(s):  
Dna Microarray ◽  
Spontaneous Bacterial Peritonitis ◽  
Bacterial Species ◽  
Rapid Identification ◽  
Bacterial Dna ◽  
Bacterial Peritonitis ◽  
Cirrhotic Patients

scholarly journals Rapid Detection, Identification, and Enumeration ofEscherichia coli Cells in Municipal Water by Chemiluminescent In Situ Hybridization

2001 ◽  
Vol 67 (1) ◽  
pp. 142-147 ◽  
Author(s):  
Henrik Stender ◽  
Adam J. Broomer ◽  
Kenneth Oliveira ◽  
Heather Perry-O'Keefe ◽  
Jens J. Hyldig-Nielsen ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
16S Rrna ◽  
Sensitivity And Specificity ◽  
Bacterial Species ◽  
Rdna Sequence ◽  
Sequence Information ◽  
Sequence Alignments ◽  
E Coli ◽  
Municipal Water

ABSTRACT A new chemiluminescent in situ hybridization (CISH) method provides simultaneous detection, identification, and enumeration of culturableEscherichia coli cells in 100 ml of municipal water within one working day. Following filtration and 5 h of growth on tryptic soy agar at 35°C, individual microcolonies of E. coliwere detected directly on a 47-mm-diameter membrane filter using soybean peroxidase-labeled peptide nucleic acid (PNA) probes targeting a species-specific sequence in E. coli 16S rRNA. Within each microcolony, hybridized, peroxidase-labeled PNA probe and chemiluminescent substrate generated light which was subsequently captured on film. Thus, each spot of light represented one microcolony of E. coli. Following probe selection based on 16S ribosomal DNA (rDNA) sequence alignments and sample matrix interference, the sensitivity and specificity of the probe Eco16S07C were determined by dot hybridization to RNA of eight bacterial species. Only the rRNA of E. coli and Pseudomonas aeruginosa were detected by Eco16S07C with the latter mismatch hybridization being eliminated by a PNA blocker probe targetingP. aeruginosa 16S rRNA. The sensitivity and specificity for the detection of E. coli by PNA CISH were then determined using 8 E. coli strains and 17 other bacterial species, including closely related species. No bacterial strains other thanE. coli and Shigella spp. were detected, which is in accordance with 16S rDNA sequence information. Furthermore, the enumeration of microcolonies of E. coli represented by spots of light correlated 92 to 95% with visible colonies following overnight incubation. PNA CISH employs traditional membrane filtration and culturing techniques while providing the added sensitivity and specificity of PNA probes in order to yield faster and more definitive results.

On properties of seawater defined by temperature, salinity, and pressure

2021 ◽  
Vol 79 (3) ◽  
pp. 121-147
Author(s):  
George Veronis
Keyword(s):  
Vertical Direction ◽  
Great Depth ◽  
Local Potential ◽  
Potential Density ◽  
Marine Research ◽  
Station Data ◽  
Starting Point ◽  
The World ◽  
Gravitational Stability

Hydrographic station data, consisting principally of temperature and salinity determinations, have been used by physical oceanographers to develop a climatological picture of the distribution of these quantities in the oceans of the world. Density as determined by Knudsen's formula, taken together with hydrostatic and geostrophic dynamics, also provides a crude picture of oceanic flow. However, the data probably contain substantially more information than has been derived from them in the past.The quantity that is orthogonal to potential-density curves in the S plane is suggested as a useful variable to complement the information contained in potential density. The derivation of this quantity, denoted by τ in this paper, is straightforward. A polynomial expression for τ that is suitable for computer calculations of τ from hydrographic station data is given. Shown are examples of hydrographic station data from the Atlantic plotted on the τσ diagram. The information contained in the τσ diagram shows many of the features exhibited in the TS plane. Vertical sections of τ appear to provide information about mixing in different parts of the Atlantic. The distribution of τ for abyssal waters at selected stations in the oceans of the world resembles the distribution of abyssal density as plotted by Lynn and Reid (1968). From the data presented, it appears that τ may serve as a good tracer for abyssal water movements.Since τ is defined to be orthogonal to σ, the expectation is that τ is a dynamically passive variable. However, since σ does not correlate with abyssal densities, it appears to lose dynamical significance at great depth, and τ assumes dynamical significance because of its orthogonality to σ. This unexpected feature leads to an exploration of the dynamical significance of σ. A natural starting point is the question of stability of abyssal water.A distinction is made between stability as determined by in situ determinations and as determined by the potential-density (σ) distribution. Simple examples are presented to show that analysis based on σ alone can lead to incorrect conclusions about gravitational stability of the water in the abyssal ocean. The reason is that seawater is a multicomponent thermodynamic system, and the thermodynamic coefficients are functions of pressure, salinity, and temperature. This functional dependence leads to adjustments in density as a water particle moves adiabatically in the vertical direction so that a layer of water that appears to be unstable near the surface may be stable (as determined by in situ determination) at great depth. A local potential density, which is simply the vertical integral of the in situ stability, is derived. This quantity gives a precise picture of gravitational stability in the vertical direction. Some distributions of local potential density are shown.Originally published May 15, 1972, in the Journal of Marine Research 30(2), 227???255.

scholarly journals Bacterial response to graphene oxide and reduced graphene oxide integrated in agar plates

2018 ◽  
Vol 5 (11) ◽  
pp. 181083 ◽  
Author(s):  
V. R. S. S. Mokkapati ◽  
Santosh Pandit ◽  
Jinho Kim ◽  
Anders Martensson ◽  
Martin Lovmar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Bacterial Growth ◽  
Bacterial Species ◽  
Bacterial Activity ◽  
Bacterial Physiology ◽  
Bacterial Response ◽  
Solid Agar ◽  
Reduced Graphene ◽  
Set Up

There are contradictory reports in the literature regarding the anti-bacterial activity of graphene, graphene oxide (GO) and reduced graphene oxide (rGO). This controversy is mostly due to variations in key parameters of the reported experiments, like: type of substrate, form of graphene, number of layers, type of solvent and most importantly, type of bacteria. Here, we present experimental data related to bacterial response to GO and rGO integrated in solid agar-based nutrient plates—a standard set-up for bacterial growth that is widely used by microbiologists. Bacillus subtilis and Pseudomonas aeruginosa strains were used for testing bacterial growth. We observed that plate-integrated rGO showed strong anti-bacterial activity against both bacterial species. By contrast, plate-integrated GO was harmless to both bacteria. These results reinforce the notion that the response of bacteria depends critically on the type of graphene material used and can vary dramatically from one bacterial strain to another, depending on bacterial physiology.

scholarly journals In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  
Keyword(s):  
Lipid A ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Lungs ◽  
Fluorescent Peptide ◽  
Bacterial Lipid

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.

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