X-ray Pictures of Micro-organisms

1913 ◽  
Vol 108 (5) ◽  
pp. 115-115
Author(s):  
Alfred Gradenwitz
Keyword(s):  
X Ray ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 5673-5680
Author(s):  
Muthukrishnan Francklin Philips ◽  
Jothirathinam Thangarathinam ◽  
Jayakumar Princy ◽  
Cyril Arockiaraj Crispin Tina ◽  
Cyril Arockiaraj Crispin Tina ◽  
...  

The authors report the preparation of the nanocomposite comprising of vanadium pentoxide (V2O5) and selenium (Se) nanoparticles and functionalized multiwalled carbon nanotubes (MWCNTs) (V2O5@Se NPs/MWCNTs). Since Se NPs possesses extraordinary physicochemical properties including larger surface area with higher adsorption capacity, V2O5 NPs were adsorbed onto Se NPs surface through physisorption process (designated as V2O5@Se NPs). The nanocomposite synthesized hydrothermally was evaluated for its antimicrobial activity. The morphology and microstructure of the nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy (UV-Vis) were employed to analyze the spectral properties of nanocomposite. The microbicidal efficacy of nanocomposite was tested against Gram-negative (G-)ZGram-positive (G+) bacteria and fungus. This is the first report on the synthesis of V2O5@Se NPs/MWCNTs nanocomposites by chemical method that showed microbicidal effect on micro-organisms. The thiol (-SH) units facilitates the enrichment of V2O5@Se NPs onto MWCNTs surface. Ultimately, it reflects on the significant antimicrobial activity of V2O5@Se NPs/MWCNTs.


1990 ◽  
Vol 22 (1-2) ◽  
pp. 1-16 ◽  
Author(s):  
P. G. Rouxhet ◽  
N. Mozes

The thermodynamic approach of adhesion and DLVO theory are complementary to predict initial bacterial adhesion; the interplay between short- and long-range forces, respectively, may be due to surface roughness. Due to the influence of electrical double layer interactions, adhesion can be promoted by treatments leading to modification of the cell or support surface properties. Adhesion is influenced by cell-cell interactions, by the cpresence of polymer molecules on the surface and by the composition of the medium. X-ray photoelectron spectroscopy can be applied to determine the elemental composition of the surface of microorganisms; some information on the chemical functions can also be obtained. The surface composition is related to physico-chemical properties which play a determining role in adhesion and flocculation, in particular the hydrophobicity and the zeta potential.


2011 ◽  
Vol 10 (3) ◽  
pp. 221-229 ◽  
Author(s):  
J.M. Kotler ◽  
R.C. Quinn ◽  
B.H. Foing ◽  
Z. Martins ◽  
P. Ehrenfreund

AbstractPhyllosilicate minerals and hydrated sulphate minerals have been positively identified on the surface of Mars. Studies conducted on Earth indicate that micro-organisms influence various geochemical and mineralogical transitions for the sulphate and phyllosilicate minerals. These minerals in turn provide key nutrients to micro-organisms and influence microbial ecology. Therefore, the presence of these minerals in astrobiology studies of Earth–Mars analogue environments could help scientists better understand the types and potential abundance of micro-organisms and/or biosignatures that may be encountered on Mars. Bulk X-ray diffraction of samples collected during the EuroGeoMars 2009 campaign from the Mancos Shale, the Morrison and the Dakota formations near the Mars Desert Research Station in Utah show variable but common sedimentary mineralogy with all samples containing quantities of hydrated sulphate minerals and/or phyllosilicates. Analysis of the clay fractions indicate that the phyllosilicates are interstratified illite–smectites with all samples showing marked changes in the diffraction pattern after ethylene glycol treatment and the characteristic appearance of a solvated peak at ∼17 Å. The smectite phases were identified as montmorillonite and nontronite using a combination of the X-ray diffraction data and Fourier–Transform Infrared Spectroscopy. The most common sulphate mineral in the samples is hydrated calcium sulphate (gypsum), although one sample contained detectable amounts of strontium sulphate (celestine). Carbonates detected in the samples are variable in composition and include pure calcium carbonate (calcite), magnesium-bearing calcium carbonate (dolomite), magnesium, iron and manganese-bearing calcium carbonate (ankerite) and iron carbonate (siderite). The results of these analyses when combined with organic extractions and biological analysis should help astrobiologists and planetary geologists better understand the potential relationships between mineralogy and microbiology for planetary missions.


2020 ◽  
Author(s):  
Benedikt Geier ◽  
Janina Oetjen ◽  
Bernhard Ruthensteiner ◽  
Maxim Polikarpov ◽  
Harald Gruber-Vodicka ◽  
...  

AbstractOur understanding of metabolic interactions between small symbiotic animals and bacteria or parasitic eukaryotes that reside within their body is extremely limited. This gap in knowledge originates from a methodological challenge, namely to connect histological changes in host tissues induced by beneficial and parasitic (micro)organisms to the underlying metabolites. To close this gap, we developed chemo-histo-tomography (CHEMHIST), a culture-independent approach to connect anatomic structure and metabolic function in millimeter-sized symbiotic animals. CHEMHIST combines spatial metabolomics based on mass spectrometry imaging (MSI) and microanatomy-based micro-computed X-ray tomography (microCT) on the same animal. Both high-resolution MSI and microCT allowed us to correlate the distribution of metabolites to the same animal’s three-dimensional (3D) histology down to sub-micrometer resolutions. Our protocol is compatible with tissue specific DNA sequencing and fluorescence in situ hybridization (FISH) for the taxonomic identification and localization of the associated micro(organisms). Building CHEMHIST upon in situ imaging, we sampled an earthworm from its natural habitat and created an interactive 3D model of its physical and chemical interactions with bacteria and parasitic nematodes in its tissues. Combining MSI and microCT, we introduce a workflow to connect metabolic and anatomic phenotypes of small symbiotic animals that often represent keystone species for ecosystem-functioning.SignificanceMetabolites mediate the establishment and persistence of most inter-kingdom symbioses. Still, to pinpoint the metabolites each partner displays upon interaction remains the biggest challenge in studying multi-organismal assemblages. Addressing this challenge, we developed a correlative imaging workflow to connect the in situ production of metabolites with the organ-scale and cellular 3D distributions of mutualistic and pathogenic (micro)organisms in the same host animal. Combining mass spectrometry imaging and micro-computed X-ray tomography provided a culture-independent approach, which is essential to include the full spectrum of naturally occurring interactions. To introduce the potential of combining high-resolution tomography with metabolite imaging, we resolve the metabolic interactions between an invertebrate host, its symbiotic bacteria and tissue parasites at unprecedented detail for model and non-model symbioses.


2019 ◽  
Author(s):  
Martin Lepsik ◽  
Roman Sommer ◽  
Sakonwan Kuhaudomlarp ◽  
Mickaёl Lelimousin ◽  
Emanuele Paci ◽  
...  

ABSTRACTPathogenic micro-organisms utilize protein receptors in adhesion to host tissues, a process that in some cases relies on the interaction between lectin and human glycoconjugates. Oligosaccharide epitopes are recognized through their three-dimensional structure and their flexibility is a key issue in specificity. In this paper, we analyse by X-ray crystallography the structures of the lectin LecB from two strains of Pseudomonas aeruginosa in complex with Lewis x oligosaccharide present on cell surfaces of human tissues. An unusual conformation of the glycan was observed in all binding sites with a non-canonical syn orientation of the N-acetyl group of N-acetyl-glucosamine. A PDB-wide search revealed that such an orientation occurs only in 2% of protein/carbohydrate complexes. Theoretical chemistry calculations showed that the observed conformation is unstable in solution but stabilised by the lectin. A reliable description of LecB/Lewis x complex by force field-based methods had proven as especially challenging due to the special feature of the binding site, two closely apposed Ca2+ ions which induce strong charge delocalisation. By comparing various force-field parametrisations, we design general protocols which will be useful in near future for designing carbohydrate-based ligands (glycodrugs) against other calcium-dependent protein receptors.


2021 ◽  
Author(s):  
Thibaud Rossel ◽  
Bing Zhang ◽  
Raphael Gobat

<div><div><div><p>Designing the perfect sensor is the dream of any chemist. Since decades, a wide diversity of chemosensors targeting analytes has been explored in chemistry. Their chemical optimization is hard and with no guarantee of success. In this context, we propose a fast and easy-to-assemble colorimetric bio-chemical receptor coined Enzyvitand. It consists only of commercial chemicals. It relies on the reunification of combinatorial chemistry, first and second coordination spheres interactions and indicators displacement assays. All harbored within a protein cavity. The sensor is highly modular, cheap and evolvable. Thanks to its solved X-ray structure, we rationally designed it for the naked-eye recognition of dopamine. Hence, our sensor imitates a biological receptor for the recognition of neurotransmitters. Its immediate high versatility and evolvability is valuable for the selective detection of a wide assortment of analytes from small molecules up to micro-organisms. For the future, we anticipate new biotechnological or immunotherapeutic applications of our bio-sensor.</p></div></div></div>


2020 ◽  
Vol 45 (1) ◽  
pp. 3-14
Author(s):  
Winston I. Lu ◽  
Dominic P. Lu

The purpose of this research was to proce or disprove the widely held beliefs that X-ray radiation used in medical or dental applications may affect the normal oral flora, and may also have effects on the micro-organisms existing in the oral cavity of every person. Such beliefs might be due to the common knowledge that radiation therapy has been utilized for the long time in the cancer patients to destroy the cancerous cells, and that radiation are also widely used in agriculture to prolong the shelf life of the farm products by destroying the decay-causing microorganisms existing in the agricultural products such as meats, produce, etc. Since very few research has been conducted in this concerned area, and not much pertinent information in the scientific literature could be found in this regard, a research experiment was set up to find out if these common beliefs have any merits. The research experiment involved selecting BDORT(By-digital O-Ring Test) positive dishes to incubate human saliva collected from a volunteer patient. Once dish served as control which was not subjected X-ray irradiation. Other dishes were subjected X-ray irradiation with various doses of irradiation strength at various time interval such as 1, 3, 5, 7, and 9 seconds to find out if any significant change taken place in the bacteria colonies. The bacterial colonies in the irradiated dishes then compared with that of the control dish so as to draw a conclusion if radiation for medical and dental X-ray machines would actually have any bactericidal or/and bacteriostatic effects on the oral micro-organisms flora. Finally, dishes were brought to a local hospital Radiology Department to use high dose of irradaition (used for cancer therapy) on the dishes to find out to what extent if such a high dose X-ray irradiation emitted from therapeutic cancer therapy machine would affect the number of bacterial colonies in the dishes as when compared with when dishes were under low doses of X-ray irradiation from dental or medical diagnostic X-ray machines. During the experiment, dishes, when irradiated, were sent to a certified medical technologist in the hospital laboratory to count the number of the bacterial colonies, and each change in the bacterial colony number were recorded in to data for biostatic analysis. The data were compared with BDORT negativity scores collected each time before and after dishes were irradiated, thus to find out if any corresponding confirmity between traditional laboratory findings and the score changes from BDORT findings. The results of this experiment revealed the fact that radiation from regular diagnostic X-ray machines possess little effect on bacteria, and that they have little effect on both cells and bacteria present in the human body. Neverthless, dramatically increasing the high radiation dosages does have potential to both inhibit and destroy bacteria. Therefore,using irradiation techniques to inhibit bacterial growth is only useful in agriculture practices, since tens of thousands of irradaiation dosages are necessary for bacteria inhibition. in human, over 500 RADs (radiation absorption dose) is lethal. Therefore, bacterial inhibition could not be practical in humans since it requires tens of thousands of RADs to be useful in the aspect.


2021 ◽  
Author(s):  
Thibaud Rossel ◽  
zhang Bing ◽  
Raphael Gobat

Designing the perfect sensor is the dream of any chemist. Since decades, a wide diversity of synthetic receptors targeting analytes has been explored in chemistry. Their chemical optimization is hard and with no guarantee of success. In this context, we propose a fast and self assembling colorimetric bio-chemical receptor coined Enzyvitand. It consists only of commercial chemicals. It relies on the reunification of combinatorial chemistry , first and second coordination spheres interactions and indicators displacement assays. All harbored within a protein cavity. The sensor is highly modular, cheap and evolvable. Thanks to its solved X-ray structure, we rationally designed it for the selectiv naked-eye recognition of dopamine over other neutrotransmitters through second coordination sphere. Hence, our sensor imitates a biological receptor for the recognition of neurotransmitters. Finally, it works in complex samples such as urine. Its immediate high versatility and evolvability is valuable for the selective detection of a wide assortment of analytes from small molecules up to micro-organisms. For the future, we anticipate new biotechnological or immunotherapeutic applications of our synthetic oligomer.


Sign in / Sign up

Export Citation Format

Share Document