NaGdF4:Eu3+ Nanoparticles for Enhanced X-ray Excited Optical Imaging.

X-ray luminescent nanoparticles (NPs), including lanthanide fluorides, have been evaluated for application to deep tissue in vivo molecular imaging using optical tomography. A combination of high material density, higher atomic number and efficient NIR luminescence from compatible lanthanide dopant ions indicates that particles that consist of ALnF4 (A = alkaline, Ln = lanthanide element) may offer a very attractive class of materials for high resolution, deep tissue imaging with X-ray excitation. NaGdF4:Eu3+ NPs produced an X-ray excited luminescence that was among the most efficient of nanomaterials that have been studied thus far. We have systematically studied factors such as (a) the crystal structure that changes the lattice environment of the doped Eu3+ ions within the unit cell; and extrinsic factors such as (b) a gold coating (with attendant biocompatibility) that couples to a plasmonic excitation, and (c) changes in the NPs surface properties via changes in the pH of the suspending medium-all with a significant impact on the X-ray excited luminescence of NaGdF4:Eu3+NPs. The luminescence from an optimally doped hexagonal phase NaGdF4:Eu3+ nanoparticle was 25% more intense compared to that of a cubic structure. We observed evidence of plasmonic reabsorption of midwavelength emission by a gold coating on hexagonal NaGdF4:Eu3+ NPs; fortunately, the NaGdF4:Eu3+ @Au core-shell NPs retained the efficient 5D0→7F4 NIR (692 nm) luminescence. The NaGdF4:Eu3+ NPs exhibited sensitivity to the ambient pH when excited by X-rays, an effect not seen with UV excitation. The sensitivity to the local environment can be understood in terms of the sensitivity of the excitons that are generated by the high energy X-rays (and not by UV photons) to crystal structure and to the surface state of the particles

Pharmacognostic and preliminary phytochemical screening of Trachyspermum khasianum H. Wolff.

Traditional systems of medicine are one of the widely practised systems of medicine in the northeastern part of India. Since ancient times plants are believed to have miraculous healing properties and playing a vital role in the management of different disease conditions. This study aimed to determine the pharmacognostical and phytochemicals properties of a rare ethnomedicinal plant Trachyspermum khasianum H. Wolff mainly found in the north-eastern part of India (Assam and Meghalaya). T. khasianum is a plant used as traditional medicine for the treatment of throat-pain, toothache and stomach ache by traditional healers of Meghalaya, India. The pharmacognostical evaluations of T. khasianum H. Wolff i.e., leaves, stems and roots like macroscopy and microscopy were carried out separately. The physicochemical parameters include moisture contents, water extractive, ethanol extractive, chloroform extractive, total ash values such as acid insoluble ash and water-soluble ash were evaluated. The different prepared extracts were submitted for various phytochemicals screening such as tests for alkaloids, glycosides, phenolic compounds, flavonoids, tannins, carbohydrates, proteins, and amino acids, fixed oils and fats, terpenoids, and diterpenes. Further study required to be carried out to determine the specific components responsible for the reported therapeutic activities

Pharmacognostic and preliminary phytochemical screening of Trachyspermum khasianum H. Wolff.

101-109Traditional systems of medicine are one of the widely practised systems of medicine in the northeastern part of India. Since ancient times plants are believed to have miraculous healing properties and playing a vital role in the management of different disease conditions. This study aimed to determine the pharmacognostical and phytochemicals properties of a rare ethnomedicinal plant Trachyspermum khasianum H. Wolff mainly found in the north-eastern part of India (Assam and Meghalaya). T. khasianum is a plant used as traditional medicine for the treatment of throat-pain, toothache and stomach ache by traditional healers of Meghalaya, India. The pharmacognostical evaluations of T. khasianum H. Wolff i.e., leaves, stems and roots like macroscopy and microscopy were carried out separately. The physicochemical parameters include moisture contents, water extractive, ethanol extractive, chloroform extractive, total ash values such as acid insoluble ash and water-soluble ash were evaluated. The different prepared extracts were submitted for various phytochemicals screening such as tests for alkaloids, glycosides, phenolic compounds, flavonoids, tannins, carbohydrates, proteins, and amino acids, fixed oils and fats, terpenoids, and diterpenes. Further study required to be carried out to determine the specific components responsible for the reported therapeutic activities

Cephamycin Resistance in Clinical Isolates and Laboratory-derived Strains of Escherichia coli, Nova Scotia, Canada

AmpC β-lactamase, altered porins, or both are usually responsible for cefoxitin resistance in Escherichia coli. We examined the relative importance of each. We studied 18 strains of clinical isolates with reduced cefoxitin susceptibility and 10 initially-susceptible strains passaged through cefoxitin-gradient plates. Of 18 wild-resistant strains, 9 had identical promoter mutations (including creation of a consensus 17-bp spacer) and related pulsed-field gel electrophoresis patterns; the other 9 strains were unrelated. Nine strains had attenuator mutations; two strains did not express OmpC or OmpF. After serial passage, 8 of 10 strains developed cefoxitin resistance, none developed promoter or attenuator mutations, 6 lost both the OmpC and OmpF porin proteins, and 1 showed decreased production of both. One strain had neither porin alteration or increased AmpC production. Porin mutants may occur more commonly and be less fit and less inclined to spread or cause disease than strains with increased β-lactamase expression

Novel lanthanide-labeled metal oxide nanoparticles improve the measurement of in vivo clearance and translocation

Abstract The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized. Following instillation, the concentrations of particles in organs were determined with inductively coupled plasma mass spectrometry. The protein corona coating the nanoparticles was found to be similar to the coating on more environmentally relevant nanoparticles such as iron oxide. Measurements of the solubility of the nanoparticles in surrogates of biological fluids indicated very little propensity for dissolution, and the elemental ratio of particle constituents did not change, adding further support to the contention that intact nanoparticles were measured. The particles were intratracheally instilled into the mouse lung. After 24 hours, the target organs were harvested, acid digested and the nanoparticle mass in each organ was measured by inductively coupled plasma mass spectrometry (ICP-MS). The nanoparticles were detected in all the studied organs at low ppb levels; 59% of the particles remained in the lung. A significant amount of particles was also detected in the feces, suggesting fast clearance mechanisms. The nanoparticle system used in this work is highly suitable for quantitatively determining deposition, transport and clearance of nanoparticles from the lung, providing a quantified measure of delivered dose.</p

Tapping the nucleotide pool of the host: novel nucleotide carrier proteins of Protochlamydia amoebophila

Protochlamydia amoebophila UWE25 is related to the Chlamydiaceae comprising major pathogens of humans, but thrives as obligate intracellular symbiont in the protozoan host Acanthamoeba sp. The genome of P. amoebophila encodes five paralogous carrier proteins belonging to the nucleotide transporter (NTT) family. Here we report on three P. amoebophila NTT isoforms, PamNTT2, PamNTT3 and PamNTT5, which possess several conserved amino acid residues known to be critical for nucleotide transport. We demonstrated that these carrier proteins are able to transport nucleotides, although substrate specificities and mode of transport differ in an unexpected manner and are unique among known NTTs. PamNTT2 is a counter exchange transporter exhibiting submillimolar apparent affinities for all four RNA nucleotides, PamNTT3 catalyses an unidirectional proton-coupled transport confined to UTP, whereas PamNTT5 mediates a proton-energized GTP and ATP import. All NTT genes of P. amoebophila are transcribed during intracellular multiplication in acanthamoebae. The biochemical characterization of all five NTT proteins from P. amoebophila in this and previous studies uncovered that these metabolically impaired bacteria are intimately connected with their host cell’s metabolism in a surprisingly complex manner

Diversity of swine Bordetella bronchiseptica isolates evaluated by RAPD analysis and PFGE

The degree of genetic diversity in 45 Bordetella (B.) bronchiseptica strains comprised of a vaccine strain (N = 1), reference strains (N = 3) and field isolates (N = 41) was evaluated using random amplified polymorphic DNA (RAPD) fingerprinting and pulsed-field gel electrophoresis (PFGE). Three candidate primers were selected for RAPD analysis after screening 20 random decamer oligonucleotides for their discriminatory abilities. The OPA-07, OPA-08 and OPA-18 primers yielded 10, 10, and 6 distinct fingerprint patterns, respectively. The most common identical RAPD pattern was produced by OPA-07 which was shared by 32 isolates (71.1%), the pattern produced by OPA-08 was shared by 26 isolates (57.8%), and the pattern produced by OPA-18 was shared by 40 isolates (88.9%). The RAPD patterns of the vaccine strain and the 3 reference strains did not match any of the patterns produced by the field isolates when primers OPA-07 and OPA-08 were used. PFGE using the restriction endonuclease XbaI produced a total of 15 patterns consisting of 4 PFGE types (A, B, B1 and C, differing by ≥ 4 bands) and 11 A subtypes (differing by ≤ 3 bands). Most of the field isolates exhibited identical type A and B patterns, suggesting that they were related. The vaccine strain and the three reference strains showed different PFGE patterns as compared to the identical type A strains

Structural basis of terephthalate recognition by solute binding protein TphC

From Springer Nature via Jisc Publications RouterHistory: received 2021-03-24, accepted 2021-10-06, registration 2021-10-12, pub-electronic 2021-10-29, online 2021-10-29, collection 2021-12Publication status: PublishedFunder: Commonwealth Scholarship Commission (CSC); doi: https://doi.org/10.13039/501100000867; Grant(s): INCN-2018-57Funder: RCUK | Engineering and Physical Sciences Research Council (EPSRC); doi: https://doi.org/10.13039/501100000266; Grant(s): EP/M013219/1, EP/023755/1Funder: RCUK | Biotechnology and Biological Sciences Research Council (BBSRC); doi: https://doi.org/10.13039/501100000268; Grant(s): BB/M011208/1, BB/M011208/1, BB/P01738X/1Abstract: Biological degradation of Polyethylene terephthalate (PET) plastic and assimilation of the corresponding monomers ethylene glycol and terephthalate (TPA) into central metabolism offers an attractive route for bio-based molecular recycling and bioremediation applications. A key step is the cellular uptake of the non-permeable TPA into bacterial cells which has been shown to be dependent upon the presence of the key tphC gene. However, little is known from a biochemical and structural perspective about the encoded solute binding protein, TphC. Here, we report the biochemical and structural characterisation of TphC in both open and TPA-bound closed conformations. This analysis demonstrates the narrow ligand specificity of TphC towards aromatic para-substituted dicarboxylates, such as TPA and closely related analogues. Further phylogenetic and genomic context analysis of the tph genes reveals homologous operons as a genetic resource for future biotechnological and metabolic engineering efforts towards circular plastic bio-economy solutions