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Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 110
Author(s):  
Amit Kumar ◽  
Xu Zhang ◽  
Oscar Vadas ◽  
Fisentzos A. Stylianou ◽  
Nicolas Dos Santos Pacheco ◽  
...  

A model for parasitic motility has been proposed in which parasite filamentous actin (F-actin) is attached to surface adhesins by a large component of the glideosome, known as the glideosome-associated connector protein (GAC). This large 286 kDa protein interacts at the cytoplasmic face of the plasma membrane with the phosphatidic acid-enriched inner leaflet and cytosolic tails of surface adhesins to connect them to the parasite actomyosin system. GAC is observed initially to the conoid at the apical pole and re-localised with the glideosome to the basal pole in gliding parasite. GAC presumably functions in force transmission to surface adhesins in the plasma membrane and not in force generation. Proper connection between F-actin and the adhesins is as important for motility and invasion as motor operation itself. This notion highlights the need for new structural information on GAC interactions, which has eluded the field since its discovery. We have obtained crystals that diffracted to 2.6–2.9 Å for full-length GAC from Toxoplasma gondii in native and selenomethionine-labelled forms. These crystals belong to space group P212121; cell dimensions are roughly a = 119 Å, b = 123 Å, c = 221 Å, α = 90°, β = 90° and γ = 90° with 1 molecule per asymmetric unit, suggesting a more compact conformation than previously proposed


Author(s):  
Amit Kumar ◽  
Xu Zhang ◽  
Oscar Vadas ◽  
Fisentzos Stylianou ◽  
Nicolas Dos Santos Pacheco ◽  
...  

A model for parasitic motility has been proposed in which parasite filamentous actin (F-actin) is attached to surface adhesins by a large component of the glideosome, known as the glideosome-associated connector protein (GAC). This large 286 kDa protein interacts at the cytoplasmic face of the plasma membrane with the phosphatidic acid-enriched inner leaflet and cytosolic tails of surface adhesins to connect them to the parasite actomyosin system. GAC is observed initially to the conoid at the apical pole and re-localised with the glideosome to the basal pole in gliding parasite. GAC presumably functions in force transmission to surface adhesins in the plasma membrane and not in force generation. Proper connection between F-actin and the adhesins is as important for motility and invasion as motor operation itself. This notion highlights the need for new structural information on GAC interactions, which has eluded the field since its discovery. We have obtained crystals that diffracted to 2.6-2.9 Å for full-length GAC from Toxoplasma gondii in native and selenomethionine-labelled forms. These crystals belong to space group P212121, cell dimensions are roughly a=119 Å, b=123Å, c=221Å, α=90, β=90, γ=90 with 1 molecule per asymmetric unit, suggesting a more compact conformation than previously proposed.


Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1344
Author(s):  
Stephanie J. Urwin ◽  
Stephanie Yerdelen ◽  
Ian Houson ◽  
Joop H. ter Horst

A thorough, systematic study into the effect that structurally related impurities have on both the process and product quality during the crystallization of an active pharmaceutical ingredient is presented. The presence of acetanilide and metacetamol influences the crystallization and product quality of paracetamol. Where high concentrations of either impurity were present in the crystallization feed, product recovery decreased by up to 15%. Acetanilide is included in the final product through adsorption onto the particle surface in concentrations up to 0.79 mol%, which can be reduced to acceptable levels through product reslurrying. The presence of metacetamol results in much higher concentrations—up to 6.78 mol% in the final product, of which approximately 1 mol% is incorporated into the crystal lattice, resulting in the perturbation of the unit-cell dimensions. The incidental crystallization and subsequent isolation of metastable Form II paracetamol increased product purity in the presence of a low metacetamol concentration. This metastable product converts to stable paracetamol Form I through reslurrying, offering an efficient metacetamol impurity rejection route. The morphology of the product is modified consistently by both impurities. An elongation of the normal prismatic shape is observed, which in the extreme case of high metacetamol contamination results in the isolation of fine, fragile needles. This problematic morphology is also improved by a reslurrying of the crystallization product to give a more equilateral shape. This systematic study of the influence of acetanilide and metacetamol on the crystallization of paracetamol builds a well-rounded picture of the concomitant impact of impurities on the principal quality attributes of a crystallization product.


Paleobiology ◽  
2021 ◽  
pp. 1-22
Author(s):  
Mathieu G. Faure-Brac ◽  
Romain Amiot ◽  
Christian de Muizon ◽  
Jorge Cubo ◽  
Christophe Lécuyer

Abstract The evolution of thermometabolism in pseudosuchians (Late Triassic to the present) remains a partly unsolved issue: extant taxa (crocodilians) are ectothermic, but the clade was inferred ancestrally endothermic. Here we inferred the thermometabolic regime of two neosuchian groups, Goniopholididae (Early Jurassic to Late Cretaceous) and Dyrosauridae (middle Cretaceous to late Eocene), close relatives of extant crocodilians, in order to elucidate the evolutionary pattern across Metasuchia (Early Jurassic to the present), a clade comprising Neosuchia (Early Jurassic to the present) and Notosuchia (Middle Jurassic until the late Miocene). We propose a new integrative approach combining geochemical analyses to infer body temperature from the stable oxygen isotope composition of tooth phosphate and paleohistology and phylogenetic comparative methods to infer resting metabolic rates and red blood cell dimensions. †Dyrosaurus and †Goniopholis share with extant crocodilians similar lifestyles, body forms, bone tissue organization, body temperatures, metabolic rates, and red blood cell dimensions. Consistently, we infer ectothermy for †Dyrosaurus and †Goniopholis with the parsimonious implication of neosuchians and metasuchians being primitively ectothermic.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sirajul Haq ◽  
Aqsa Waheed Raja ◽  
Sadiq Ur Rehman ◽  
Amine Mezni ◽  
Manel Ben Ali ◽  
...  

The NiO-ZnO nanocomposite (NiO-ZnO NC) was synthesized by ecofriendly process by using Diospyros kaki (D. kaki) extract of leaves as reducing and capping agents. X-ray diffraction (XRD) was used for examined crystallinity, cell dimensions, and crystallite size (7.6 nm). To determine the purity of sample and weight percentage, energy dispersive X-ray (EDX) is used. The surface morphology was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By using Fourier transform infrared spectroscopy (FTIR), functional groups in samples were determined. By using diffuse reflectance data (DRS), band gap energy calculated via Tauc plot was 3.23 eV. The photocatalytic activity was checked against brilliant green (BG) and 4-nitrophenol (4-NP) and 92.5% and 69.7% of brilliant green (BG) and 4-nitrophenol (4-NP) were degraded with rate of degradation which were 0.0281 and 0.011 min−1.


IAWA Journal ◽  
2021 ◽  
pp. 1-13
Author(s):  
Alan Dickson

Abstract A conventional stereo light microscope was used to image polished wood surfaces at cellular resolution over size scales of the growth ring or larger. Bandpass filtering and local area contrast enhancement were used to aid automatic image thresholding and binarisation. An estimate for the location and proportion of cell collapse was introduced based on the distance between uncollapsed cell lumens. Additionally, spatial associations between vessels were determined using a Euclidean distance transform. The analysis of pith to bark cores provided sufficient detail to show significant intra and inter-annual trends in Pinus radiata tracheid dimensions (wall thickness, wall area, and radial widths). These trends were consistent with expectations and in agreement with the literature. Measured cell dimensions may be influenced by cell collapse and deformation as a result of drying. The analysis of air, kiln and oven-dried Eucalyptus nitens showed that cell collapse was highly variable but generally more prominent in the outer third of growth rings. There were significant changes in vessel shape across the growth rings and vessel area was significantly reduced by drying. The technique provides an intermediate step between detailed microscopy and macroscopic imaging that allows spatial analysis at the wood cell level.


Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1049
Author(s):  
Ekaterina Kaneva ◽  
Tatiana Radomskaya ◽  
Roman Shendrik ◽  
Victor Chubarov ◽  
Victoria Danilovsky

In this work we report on a petrographic, crystal-chemical, and optical characterization, obtained from different analytical methods, of amphibole species. Potassic-hastingsite, ideally AKBCa2C(Fe2+4Fe3+)T(Si6Al2)O22W(OH)2, has been found in the Kedrovy district (East Siberia, Russia). The sample occurs as well-formed and large radially radiant aggregates of dark green, almost black crystals. The unit cell dimensions are a = 9.9724(3) Å, b = 18.2968(4) Å, c = 5.3573(1) Å, β = 104.945(3)°, V = 944.44(4) Å3, Z = 2. Site populations were determined by combining single-crystal structure refinement and electron probe microanalysis, and Fe3+/Fe2+ ratio was obtained from X-ray fluorescence analysis. Infrared, diffuse light UV/Vis/NIR absorption, and electron spin resonance spectra are presented and discussed. A thermoelastic behavior of a powder of potassic-hastingsite was studied by in situ high-temperature X-ray diffraction. A thermal expansion and subsequent significant contraction in the unit cell volume during a high-temperature X-ray powder diffraction experiment is observed as a consequence of the deprotonation process, which is locally balanced via oxidation of Fe2+. According to the data obtained for potassic-hastingsite, these processes occur within 400–600 °C. The thermal expansion of the mineral is anisotropic; the thermal expansivity coefficients αa: αb: αc (×10−6) = −18.06 : 9.59 : −1.09 at 400 °C, −26.15 : −1.52 : 2.22 at 600 °C and 23.77 : −25.06 : 42.08 at 750 °C.


Author(s):  
M. Singh ◽  
S. Anthal ◽  
P. Akhileshwari ◽  
M. A. Sridhar ◽  
H. M. Vinusha ◽  
...  

The structure of 2-(((6-methoxypyridin-3-yl)imino)methyl)phenol (MPIMP) (C13H12N2O2) has been determined by X-ray diffraction methods. It crystallizes in the tetragonal crystal system with space group P42/n and unit cell dimensions a = 14.2958(3) Å, b = 14.2958(3) Å, c = 11.0179(3) Å, V = 2251.73(12) Å3, Z = 8. The structure has been refined by full-matrix least square procedure to a final R-value of 0.0518(wR2= 0.1312) for 1709 observed reflections. The molecules linked via two intermolecular (C-H...N and C-H...O) hydrogen bonds. The crystal structure was further stabilized by a strong intramolecular N-H...O hydrogen bond. The Hirshfeld surface analysis reveals the interaction contacts of the molecule and the strength of molecular packing in the crystal. The energy framework has been performed through different intermolecular interaction energies for structural stability. The molecular docking of MPIMP was performed against tuberculosis enzyme Decaprenyl-phosphoryl-b-Dribose 20-epimerase (DprE1, PDB code: 4KW5) to reconnoiter the binding interactions at the active sites.


2021 ◽  
Vol 4 (2) ◽  
pp. 1067-1076
Author(s):  
Pham Hong Thai ◽  
Phan Thanh Ngoc ◽  
Ha Thi Le Huong

Stingless bees are distributed in tropical and subtropical regions. There are over 16,000 species of stingless bees around the world, among which, 42 species are from Asia (Kerr & Maule, 1964). Sixteen species of stingless bees have been identified in Vietnam (Sakagami, 1975; Sakagami, 1978; Engel, 2000; Chinh et al., 2005; Rasmussen, 2008). In this study, the biological characteristics of Tetrigonilla collina, as a representative for Southeast Asian stingless bees, were observed and recorded. The worker cell dimensions were 5.30 ± 0.34mm in length by 4.28 ± 0.37mm in width with a volume of 45.02 ± 5.74mL (food volume: 19.05 ± 3.5mL; ratio: 42.27%). The new cells were mostly built in the morning (from 2:00 to 10:00 am) and the queen laid eggs (2.52 ± 0.81 sec per egg) and capped the cells in the afternoon (from 12:00 to 17:00 pm). The average worker-cell building period was 12.03 ± 3.78 hours. Mainly, six of first ten bees that inserted made food discharges in a cell. The food discharge occurred in a very short time, which was 1.58 ± 0.6 minutes. The new cell numbers of the colony were reduced at the end of the experimental period.


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