Comparison between Echinococcus granulosus sensu stricto (G1) and E. canadensis (G6) mitochondrial genes (cox1 and nad1) and their related protein models using experimental and bioinformatics analysis

BackgroundCystic echinococcosis (CE) as a zoonotic parasitic disease, remains a health challenge in many parts of the world. There are different species of Echinococcus granulosus sensu lato with different pathogenicity and host preferences.Different procedures have been applied for characterization of Echinococcus taxa in which two mitochondrial genes, cox1 and nad1 have been used more common. They have been able to differentiate E. granulosus sensu stricto and E. canadensis species in different hosts. The affinity of E. granulosus sensu stricto and E. canadensis species for localizing different organs seems to be different. To what such affinity and related pathogenicity could be related, is not known, so far. Bioinformatics analysis may be helpful to interpret such difference by investigating the genes and their related protein models between different species infecting human and animals. The current work was designed to study the differences between E. granulosus s.s. and E. canadensis species mitochondrial genes (cox1 and nad1) and related protein models of CE cysts by experimental and bioinformatics analysis.Materials and methodsDifferent human and animal CE cysts were collected and their DNA was extracted and sequenced based on their cox1 and nad1 genes. In order to determine the E. granulosus s.s. and E. canadensis species of the samples, BLAST analysis was performed on sequenced genes. Three sequences were selected for analysis and were deposited in GenBank. Moreover, the sequence number of KT988116.1 which belonged to E. canadensis from our already deposited in GenBank was also selected. Alignment and phylogenetic analysis were performed on the sequences using BioEdit and MEGA7 software. The raw sequences of translated proteins belonged to the mentioned genes were obtained from Protein database in NCBI. The secondary structure was determined by PSIPRED Protein Sequence Analysis Workbench. The tertiary models of COX1 and NAD1 proteins in both genotypes were constructed using Modeler 9.12 software and their physicochemical features were computed using ProtParam tool in ExPASY server.ResultsBLAST analysis on sequenced genes showed that the samples belonged to E. granulosus s.s. and E. canadensis species. These sequences were deposited in GenBank with accession numbers: JN579173.1, KF437811.1, and KY924632.1.The results showed that proteins of COX1 of E. granulosus s.s., COX1of E. canadensis, NAD1of E. granulosus s.s. and NAD1of E. canadensis species, consisted of 135, 122, 120 and 124 amino acids, respectively. The aligned sequences of translated proteins belonged to COX1 and NAD1 enzymes in E. granulosus s.s. and E. canadensis species were different; such that alignment COX1 sequence between E. granulosus s.s. and E. canadensis species showed that amino acids were different in 6 positions. This difference for NAD1 sequences were different in 19 positions. The secondary structure determined by PSIPRED showed differences in coil, strand and helix chains in COX1 and NAD1 proteins in E. granulosus s.s. and E. canadensis species. Comparison between three-dimensional structures (3D) of COX1 protein model in E. granulosus s.s. and E. canadensis species demonstrated an additional helix with two conserved iron binding sites in the COX1 protein of E. granulosus s.s. species.ConclusionE. granulosus s.s. and E. canadensis species differences are reflected in two important proteins: COX1 and NAD1. These differences are demonstrable in the 3D structure of proteins of both strains. So, the present study is adding to our understanding of the difference in molecular sequences between the E. granulosus s.s. (G1) and E. canadensis (G6) which may be used for interpreting the difference between the pathogenicity and localization affinity in these two important helminthic zoonosis.     

Configuration interaction study of H2 using a modified slater-type orbital

A non-standard 1s basis function, χ = (1 + ar²) exp(?ζr), is used to approximate the ground state of the hydrogen molecule in a configuration interaction framework and using numerical integration over MO's. Results are compared to the traditional 1s STO.     

Hybridization and correlation in a model calculation of a two-electron bond

The paper presents a quantitative examination of some aspects of the molecular two-electron problem, using a calculation for a two-electron homonuclear bond based on a restricted set of one 2s and one 2p orbital per nucleus. The single-determinant approximations with pure 2s STO's and with hybrid AO's are considered, as well as “partial” configuration mixing (CI) over MO's involving one hybrid per atom and “complete” CI over the whole four-orbital basis. The calculations simulate an exact calculation as regards hybridization and (left-right) correlation effects. These are studied, for the lowest state, at various distances, introducing the axial electron density as a means for interpreting quantitatively the various effects. The importance of orthogonalizing the 2s AO's to the corresponding 1s AO's and the MO's used to the MO formed by 1s AO's is reviewed, pending further numerical analysis.     

Electron affinities of the lanthanides

The electron affinities (EA's) of the lanthanides (La through Tm) have been determined from the expression EA = IP₁ ? C)r^?1)_n1, where IP₁ is the first ionization potential and (r^?1)_n1 is the relativistic radial integral of an electron in the unfilled shell, the constant C includes the quantum numbers n, 1 of the partly filled shells and the atomic number Z of each element. The EA's vary from +0.5 eV (La) to –0.2eV (Tm) which is consistent with other semi-empirical estimates for certain lanthanide elements.     

Hund's rules

We review the present state of our undertanding of Hund's first and second rules, their domains of validity, and of generalizations in cases where the rules in their original form are invalid. These exceptions occur mainly in atomic configurations with more than one open shell withl ≥ 1, but also in cases with large orbital angular momentaL. We present a derivation of thealternating rule, which is, in some sense, a generalization of Hund's first rule, and present new rules, which generalize Hund's second rule. The importance of the concept ofunnatural parity states for an understanding of these rules is stressed. It is demonstrated that the lowest singlet-triplet average energy for the sameL corresponds to a pair of unnatural parity states (theunnatural parity rule). For sufficiently smalll ₁ andl ₂, the lowest average energy is that of the pair of states with the maximum possibleL (maximum-L rule), though exceptions are found already for moderately large values ofl ₁ andl ₂. Our analysis indicates that the validity of Hund's second rule is to some extent an accidental consequence of the minimisation of an elementary function ofl ₁,l ₂, andL — which does not depend monotonically onL — over states of unnatural parity, and that a more general and more fundamental rule should be formulated in terms of this function. We also discuss the generalisation of Hund's rules to molecules, as well as violations of them, with particular emphasis on the inversion of Hund's first rule by spin-polarization in molecules.     

Pyrethroid and Etofenprox Resistance in Anopheles gambiae and Anopheles coluzzii from Vegetable Farms in Yaoundé, Cameroon: Dynamics,Intensity and Molecular Basis

Previous studies have indicated widespread insecticide resistance in malaria vector populations from Cameroon. However, the intensity of this resistance and underlying mechanisms are poorly known. Therefore, we conducted three cross-sectional resistance surveys between April 2018 and October 2019, using the revised World Health Organization protocol, which includes resistance incidences and intensity assessments. Field-collected Anopheles gambiae s.l. populations from Nkolondom, Nkolbisson and Ekié vegetable farms in the city of Yaoundé were tested with deltamethrin, permethrin, alpha-cypermethrin and etofenprox, using 1× insecticide diagnostic concentrations for resistance incidence, then 5× and 10× concentrations for resistance intensity. Subsamples were analyzed for species identification and the detection of resistance-associated molecular markers using TaqMan® qPCR assays. In Nkolbisson, both An. coluzzii (96%) and An. gambiae s.s. (4%) were found together, whereas only An. gambiae s.s. was present in Nkolondom, and only An. coluzzii was present in Ekié. All three populations were resistant to the four insecticides (<75% mortality rates―MR1×), with intensity generally fluctuating over the time between mod-erate (<98%―MR5×; ≥98%―MR10×) and high (76–97%―MR10×). The kdr L995F, L995S, and N1570Y, and the Ace-1 G280S-resistant alleles were found in An. gambiae from Nkolondom, at 73%, 1%, 16% and 13% frequencies, respectively, whereas only the kdr L995F was found in An. gambiae s.s. from Nkolbisson at a 50% frequency. In An. coluzzii from Nkolbisson and Ekié, we detected only the kdr L995F allele at 65% and 60% frequencies, respectively. Furthermore, expression levels of Cyp6m2, Cyp9k1, and Gste2 metabolic genes were highly upregulated (over fivefold) in Nkolondom and Nkolbisson. Pyrethroid and etofenprox-based vector control interventions may be jeopardized in the prospected areas, due to high resistance intensity, with multiple mechanisms in An. gambiae s.s. and An. coluzzii.     

Synthesis and properties of novel aromatic poly(ester-imide)s bearing 1,5-bis(benzoyloxy)naphthalene units

Two series of new aromatic poly(ester-imide)s were prepared from 1,5-bis(4-aminobenzoyloxy)naphthalene (p-1) and 1,5-bis(3-aminobenzoyloxy)naphthalene (m-1), respectively, with six commercially available aromatic tetracarboxylic dianhydrides via a conventional two-stage synthesis that included ring-opening polyaddition to give poly(amic acid)s followed by chemical imidization to polyimides. The intermediate poly(amic acid)s obtained in the first stage had inherent viscosities of 0.41-0.84 and 0.66-1.37 dl/g, respectively. All the para-series and most of the meta-series poly(ester-imide)s were semicrystalline and showed less solubility. Two of the meta-series poly(ester-imide)s derived from less rigid dianhydrides were amorphous and readily soluble in polar aprotic solvents, and they could be solution-cast into transparent and tough films with good mechanical properties. The meta-series polymers derived from rigid dianhydrides were generally semicrystalline and showed less solubility. Except for one example, the meta-series poly(ester-imide)s displayed discernible T_gs in the range 239-273 °C by DSC. All of these two series poly(ester-imide)s did not show significant decomposition below 450 °C in nitrogen or in air.     

Two-color excitation of NO in a supersonic free jet. Autoionization of high rydberg states

High Rydberg states of NO above the ionization limit have been measured for the isolated molecule in a supersonic free jet by two-color multiphoton ionization. Three Rydberg series (ns, np and nf) were identified, which appeared by rotational and the vibrational autoionization. The rotational structures of the 13s(υ = 1), 13p(υ = 1) and 12f(υ = 1) states have been analyzed in detail. The fluorescence dip spectra for the intermediate A²Σ⁺(3sσ) state have been measured simultaneously and the cross sections of the one-photon absorption to the high Rydberg states from the A²Σ⁺(υ = 1) state have been determined.     

Kα3,4 satellites in Mg–Cl elements

The Kα_3,4 satellites in Mg–Cl elements are measured a high-resolution double-spectrometer. Intensity ratio of the Kα_3,4 satellites in these elements relative to the Kα_1,2,3,4 emission lines are compared with those obtained theoretically by a sudden approximation. Moreover, the origin of the Kα_3,4 satellites, especially, for Mg, Al, and Si could not be explained clearly by the contribution of the 1s2s→2s2p and 1s2p→(2p)² spectator holes using GRASP2 code.     

A reproducible method for preparation and operation of microwave excited electrodeless discharge lamps: SIMPLEX optimization of experimental factors for a cadmium lamp

By means of a SIMPLEX optimization procedure, cadmium electrodeless discharge lamps (EDLs) operated at microwave frequencies (2450 MHz) were prepared and optimized with respect to: weight of cadmium, W₁ = 680–750 μg; time interval of the EDL blank under vacuum after water removal, t₁ = 0–1000 s; pressure of argon gas (under microwave excitation) during preparation, A₁ = 1–2.5 torr; microwave power for discharge during preparation, P₁ = 90–10O W; time interval for microwave discharge during preparation, t₂ = 20–28 s; time for EDL to cool before evacuation, t₃ = 240 s; time under vacuum after cooling period, t₄ = 0–500 s; pressure of argon to fill lamp, A₂ = 6–9 torr; microwave power for operation of EDL, P₂ = 55–65 W; and operating temperature of EDL, T = 290–330°C. Under the above conditions, EDLs were prepared reproducibly (atomic fluorescence detection limits were all within a factor of 3 or less). The resulting EDLs were consistently as good as or better than the best EDLs prepared in the past by the laboratory. Throughout the SIMPLEX optimization procedure, no EDL failed; all EDLs behaved as would be predicted by the preparation procedure.     

Effects of X-ray radiation on the surface chemical composition of plasma deposited thin fluorocarbon films

Different thin fluorocarbon (FC) films were deposited on Si(111) using plasma polymerisation and then exposed to X-ray radiation. Changes in the chemical composition of the deposited fluorocarbon films as a function of irradiation time were investigated in situ using X-ray photoelectron spectroscopy. The evaluation of the C1s and F1s core level induced emission as a function of exposure to X-ray radiation (Mg Kα, hν = 1253.6 eV) reveals changes in the surface chemical composition of the FC polymer structure. The presented results indicate a high defluorination under X-ray irradiation. Additionally, binding energy shifts of the F1s and C1s peaks during the exposure associated with surface charging effects were observed. With ongoing exposure the surface charging decreases continuously and the FC surfaces become more conductive due to changes in the polymer structure. Different models have been used to describe the decomposition kinetics and surface composition.     

Crystal Structures of the Plant Phospholipase A1 Proteins Reveal a Unique Dimerization Domain

Phospholipase is an enzyme that hydrolyzes various phospholipid substrates at specific ester bonds and plays important roles such as membrane remodeling, as digestive enzymes, and the regulation of cellular mechanism. Phospholipase proteins are divided into following the four major groups according to the ester bonds they cleave off: phospholipase A1 (PLA1), phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Among the four phospholipase groups, PLA1 has been less studied than the other phospholipases. Here, we report the first molecular structures of plant PLA1s: AtDSEL and CaPLA1 derived from Arabidopsis thaliana and Capsicum annuum, respectively. AtDSEL and CaPLA1 are novel PLA1s in that they form homodimers since PLAs are generally in the form of a monomer. The dimerization domain at the C-terminal of the AtDSEL and CaPLA1 makes hydrophobic interactions between each monomer, respectively. The C-terminal domain is also present in PLA1s of other plants, but not in PLAs of mammals and fungi. An activity assay of AtDSEL toward various lipid substrates demonstrates that AtDSEL is specialized for the cleavage of sn-1 acyl chains. This report reveals a new domain that exists only in plant PLA1s and suggests that the domain is essential for homodimerization.     

Carbon-13 NMR relaxation time measurements of molybdenum carbonyl physisorbed on alumina

In order to obtain information about the motion of Mo(CO)₆ physisorbed on high surface area alumina, the temperature dependences of ¹³C NMR relaxation times, T₁ and T₂, have been measured at 7.05 T. Eight samples prepared under various conditions were studied. Two types of alumina (γ and η) were used and the alumina in two samples was pretreated with iron nitrate. A T₁ minimum of 0.4 s at 220 K observed for most samples corresponds to a correlation time of 2 × 10⁻⁹ s. The dominant relaxation mechanism is not chemical shift anisotropy since T₁ measurements at 3.5 T indicated no field dependence. An increase in the iron content of the alumina decreased T₁ above 273 K but caused only minor changes in T₁ and T₂ at lower temperatures. T₁ was 0.73 s and T₂ was 11 ms for Mo(CO)₆ on the η-alumina sample at 300 K.     

Three-component conformational equilibria of some flexible pyrrolidin-2-(thi)ones in solution by NMR data (δC, δH, and JHH) and their DFT predictions: a confrontation of different approaches

Three standard gas-phase B3LYP/6-31G(d) methods of the analysis of δ_C, δ_H, and J_HH NMR data for solutions initially used for the title γ-lactams 1a-c led to conflicting findings on fractional populations ηs of their fast interconverting conformers A-C, which were also inconsistent with energy data. In order to find the source(s) of these discrepancies, several additional DFT computations were carried out at the double- and triple-zeta theory level with simultaneous modeling of the solutions in explicit solvents with the COSMO or IEF-PCM technique. The WC04/WP04 functionals and IGLO-II (or IGLO-III) basis set were applied for predicting δ_C/δ_H, and J_HH data, respectively. The limits of efficiency and accuracy of a few current NMR-oriented computational protocols were determined by their specific use to the main forms of 1a-c treated as test cases. Thus, an unreliability of the modified Karplus-type equation for this purpose was shown. In turn, only the use of DFT-D3 corrections for the attractive van der Waals dispersion interactions (London forces) not present in conventional DFT, to Gibbs free energies (ΔG) estimated for the forms A-C of 1a-c in solution, yielded energetics and so populations (η_Gs) compatible within ±15% (only ±2%, for 1a) with the best results found by considering the ¹H NMR data. These η_Hs were found by a linear regression of GIAO-predicted δ_H sets reproducing experiment in the best way (r²>0.9996, for 1a and 1b, r²=0.9970, for 1c with strongly degenerated δ_Hs). As for η_Js, they permitted only for evaluations of the ratios (A+B)/C, excepting sufficiently differentiated J_HHs (1b in acetone). In contrast, an application of δ_Cs for assessing η_Cs was unsuccessful. Selected findings were finally compared with the DP4-probability results (η_DP4s) and fairly good agreement was found. The greatest divergence in ηs exists for the CS bond-containing object 1b, what suggests a large effect of the intramolecular London forces on its structure and properties. The present results should be useful guidelines for NMR studies on the other multi-conformer systems in rapid equilibrium between more than two energetically feasible forms.     

Five-membered 2,3-dioxo heterocycles: XCVII. Reaction of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones with Fischer’s base

3-Aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones reacted with 1,3,3-trimethyl-2-methylidene-2,3-dihydro-1H-indole (Fischer’s base) to give (2Z)-1-aryl-2-[3-oxo-3,4-dihydroquinoxalin-2(1H)-ylidene]-5-(1,3,3-trimethyl-2,3-dihydro-1H-indol-2-ylidene)pentane-1,3,4-triones.     

Studies on halogen derivatives of phenylazochromotropic acid: II. Spectrophotometric microdetermination of thorium

A new rapid and accurate method for the spectrophotometric microdetermination of thorium using o, p-dichloro-, p-bromo-, and p-iodophenylazochromotropic acids is given. The optimum conditions favoring the formation of the complexes are extensively investigated. The molecular structure was found to be 1:1 and 1:2 Beer's law is obeyed up to 16.24, 18.56, and 11.60 ppm of Th using the three reagents, respectively.     

A detailed consideration of resonance radiation trapping in the argon inductively coupled plasma

The extent and duration of trapping of argon resonance radiation (106.7 and 104.8 nm) in the ICP was calculated using a model incorporating line shape contributions from both Doppler and pressure broadening. The trap was found to be at the pressure-broadened limit, giving an escape factor of 7.9 × 10^?4 when excitation of the 4s states in the plasma annulus is assumed. Theoretical apparent radiative lifetimes τ_app for argon ³P₁ and ¹P₁ resonance states are calculated to be 8 and 1.9μs respectively. The quartet of 4s states, rapidly mixed by electron collisions, are presumed to share an overall apparent radiative lifetime τ_app = 1.6μs for the purpose of plasma modeling. Effects of this radiation trapping on the argon 4s atom density and on electron-ion recombination are discussed.     

Determination of stability constants of intermediates by coordination capillary GLC. Chiral complexes of NiII and CuII with Schiff's bases (1R, 2R)-N,N′-bis(3′-tert-butylsalycilidene)diaminocyclohexane and (1R,2R)-N,N′-bis[(4-hydroxy[2.2]paracyclophanyl)-5-methylene]diaminocyclohexane as GLC phases

Chiral Ni^II and Cu^II salen complexes dissolved in the polymethylphenylsiloxane phase OV-17 were used as the phases for capillary chromatography. Chiral salen lignads are Schiff's bases obtained from salicylaldehyde (SA) and (1R,2R)-diaminocyclohexane and Schiff's bases obtained by condensation of (1R,2R)- or (1S,2S)-diaminocyclohexane with (R)-4-hydroxy-5-formyl[2.2]paracyclophane (HFPC). The stability constants of the intermediates were calculated from the retention times. The complexes based on HFPC are stronger Lewis acids than those based on SA. The ability of the substrates to form intermediates decreases in the sequence: aromatic aldehydes>halogen-substituted aromatic compounds>halogen-substituted aliphatic compounds.     

Systems Ln-Fe-O (Ln=Eu, Gd): thermodynamic properties of ternary oxides using solid-state electrochemical cells

The standard molar Gibbs energies of formation of LnFeO₃(s) and Ln₃Fe₅O₁₂(s) where Ln=Eu and Gd have been determined using solid-state electrochemical technique employing different solid electrolytes. The reversible e.m.f.s of the following solid-state electrochemical cells have been measured in the temperature range from 1050 to 1255 K.Cell (I): (−)Pt / {LnFeO₃(s)+Ln₂O₃(s)+Fe(s)} // YDT/CSZ // {Fe(s)+Fe_0.95O(s)} / Pt(+);Cell (II): (−)Pt/{Fe(s)+Fe_0.95O(s)}//CSZ//{LnFeO₃(s)+Ln₃Fe₅O₁₂(s)+Fe₃O₄(s)}/Pt(+);Cell (III): (−)Pt/{LnFeO₃(s)+Ln₃Fe₅O₁₂(s)+Fe₃O₄(s)}//YSZ//{Ni(s)+NiO(s)}/Pt(+);andCell(IV):(−)Pt/{Fe(s)+Fe_0.95O(s)}//YDT/CSZ//{LnFeO₃(s)+Ln₃Fe₅O₁₂(s)+Fe₃O₄(s)}/Pt(+).The oxygen chemical potentials corresponding to the three-phase equilibria involving the ternary oxides have been computed from the e.m.f. data. The standard Gibbs energies of formation of solid EuFeO₃, Eu₃Fe₅O₁₂, GdFeO₃ and Gd₃Fe₅O₁₂ calculated by the least-squares regression analysis of the data obtained in the present study are given byΔ_fG°_m(EuFeO₃, s) /kJ mol⁻¹ (± 3.2)=−1265.5+0.2687(T/K)   (1050 ? T/K ? 1570),Δ_fG°_m(Eu₃Fe₅O₁₂, s)/kJ mol⁻¹ (± 3.5)=−4626.2+1.0474(T/K)   (1050 ? T/K ? 1255),Δ_fG°_m(GdFeO₃, s) /kJ mol⁻¹ (± 3.2)=−1342.5+0.2539(T/K)   (1050 ? T/K ? 1570),andΔ_fG°_m(Gd₃Fe₅O₁₂, s)/kJ·mol⁻¹ (± 3.5)=−4856.0+1.0021(T/K)   (1050 ? T/K ? 1255).The uncertainty estimates for Δ_fG°_m include the standard deviation in the e.m.f. and uncertainty in the data taken from the literature. Based on the thermodynamic information, oxygen potential diagrams for the systems Eu-Fe-O and Gd-Fe-O and chemical potential diagrams for the system Gd-Fe-O were computed at 1250 K.