Orthophthaldehyde as a fluorescent probe for the feasible and sensitive assay of heptaminol: application to dosage forms and real human plasma

The antihypotensive drug heptaminol was determined using a spectrofluorimetric method and ortho-phthaladehyde as a fluorescence probe. The drug was mixed with the reagent in the presence of 2-mercaptoethanol and the reaction was carried out in slightly alkaline aqueous solution containing 0.1 M sodium hydroxide. The resulting product exhibited high fluorescence activity that was measured at 451 nm after excitation at 334 nm. The linearity range of the method was 5–100 ng ml⁻¹ with a lower detection limit of 1.8 ng ml⁻¹. The procedure was evaluated according to the International Council of Harmonization guidelines. The proposed method was applied to analyze the drug in pharmaceutical tablets and oral drops. In addition, the present study represents the first spectrofluorimetric method for the determination of the cited drug in real human plasma. The method provided high recovery percentages without any interference from coexisting pharmaceutical excipients or the components of human plasma.     

Construction of a domestic wastewater disinfection filter from biosynthesized and commercial nanosilver: a comparative study

Overproduction of desired metabolites usually sacrifices cell growth. Here we report that quorum sensing (QS) can be exploited to coordinate cell growth and lactic acid production in Escherichia coli. We engineered two QS strains: one strain overexpressing acyl-homoserine lactone (AHL) synthesis genes (“ON”), the other strain overexpressing both AHL synthesis and degradation gene (aiiA) (“ON to semi-OFF”). To clarify the impact of the QS system on lactic acid production, D-lactate dehydrogenase gene ldhA was deleted from the E. coli genome, and Enhanced Green Fluorescence Protein (eGFP) was used as the reporter. Compared to the “ON” strain, the “ON to semi-OFF” strain showed delayed log growth and decreased egfp expression at stationary phase. When egfp was replaced by ldhA for lactic acid production, compared to the wild-type strain, the “ON to semi-OFF” strain demonstrated 231.9% and 117.3% increase in D-lactic acid titer and space-time yield, respectively, while the “ON” strain demonstrated 83.6%, 31%, and 36% increase in growth rate, maximum OD600, and glucose consumption rate, respectively. Quantitative real-time PCR revealed that both ldhA and the genes for phosphotransferase system were up-regulated in ldhA-overexpressing “ON” strain compared to the strain only harboring QS system. Moreover, the “ON” strain showed considerable increase in glucose consumption after a short lag phase. Compared to the reference strain harboring only ldhA gene in vector, both the “ON” and “ON to semi-OFF” strains demonstrated synchronization between cell growth and D-lactic acid production. Collectively, QS can be leveraged to coordinate microbial growth and product formation.     

Separation of ephedrine and pseudoephedrine enantiomers using a polysaccharide‐based chiral column: A normal phase liquid chromatography–high‐resolution mass spectrometry approach

Chiral considerations are found to be very much relevant in various aspects of forensic toxicology and pharmacology. In forensics, it has become increasingly important to identify the chirality of doping agents to avoid legal arguments and challenges to the analytical findings. The scope of this study was to develop an liquid chromatography–mass spectrometry (LCMS) method for the enantiomeric separation of typical illicit drugs such as ephedrines (ie, 1S,2R(+)‐ephedrine and 1R,2S(?)‐ephedrine) and pseudoephedrine (ie, R,R(?)‐pseudoephedrine and S,S(+)‐pseudoephedrine) by using normal phase chiral liquid chromatography–high‐resolution mass spectrometry technique. Results show that the Lux i‐amylose‐1 stationary phase has very broad and balancing‐enantio‐recognition properties towards ephedrine analogues, and this immobilized chiral stationary phase may offer a powerful tool for enantio‐separation of different types of pharmaceuticals in the normal phase mode. The type of mobile phase and organic modifier used appear to have dramatic influences on separation quality. Since the developed method was able to detect and separate the enantiomers at very low levels (in pico grams), this method opens easy access for the unambiguous identification of these illicit drugs and can be used for the routine screening of the biological samples in the antidoping laboratories.     

Trehalose administration attenuates atherosclerosis in rabbits fed a high-fat diet

Disruption of macrophage autophagy is a major contributor to macrophage dysfunction and subsequent inflammation leading to atherosclerosis. Trehalose is a natural disaccharide that is able to induce macrophage autophagy-lysosomal biogenesis and reduce inflammation. Here, we studied the efficacy of intravenous trehalose administration in reducing atherosclerotic plaque burden in high-cholesterol-fed rabbits. Adult male New Zealand white Rabbits were fed with a high-fat diet containing 1% cholesterol for 8 weeks followed by a cholesterol-free diet for the next 4 weeks. In the latter 4-week phase of the cholesterol-free diet, one group received intravenous trehalose solution at a dose of 350 mg/kg, three times per week. In the control group, an equivalent volume of PBS (3 mL) was administered with the same protocol. At the end of the 12th week of the study, all rabbits were anesthetized and aortic arch sections were collected followed by hematoxylin and eosin staining and assessment of plaque grading. Fasting serum lipids were also measured using routine enzymatic methods. At the end of the 12th week, there were no significant differences in the body weight and blood lipids between the control- and trehalose-treated groups. Intravenous trehalose administration significantly attenuated atherosclerotic plaque development as revealed by reduced plaque grading ( P = 0.048) and intima/media thickness ratio ( P = 0.017). Intimal thickening was also found to be reduced in the trehalose versus control group, though this reduction did not reach statistical significance. The present study provided evidence as to the efficacy of short-term intravenous trehalose administration in regressing atherosclerotic plaque in high-fat-fed rabbits.     

Campanian–early Eocene cephalopods from Kharga Oasis,Western Desert,Egypt

The Campanian–lower Eocene sedimentary succession in the Kharga Oasis yields rare cephalopods that have so far received little attention. Eight cephalopod species; six nautiloids and two ammonites, are identified in the study area. The nautiloids are referred to five genera in three families. All nautiloid species are recorded from the Paleocene and Eocene rocks, two of which are described as new, as follows: Cimomia kurkurensis nov. sp. and Deltoidonautilus hassani nov. sp. The two ammonite species are Libycoceras ismaelis (von Zittel, 1884) and Baculites ovatus Say, 1820, representing the families Sphenodiscidae and Baculitidae, respectively. Baculites anceps of Quaas (1902, non Lamarck, 1822) from the Maastrichtian of the Western Desert of Egypt is here assigned to Baculites ovatus. The palaeobiogeography of these species is studied in detail.     

The combined effect of water deficit stress and TiO2 nanoparticles on cell membrane and antioxidant enzymes in Helianthus annuus L.

Nanotechnology has become one of the several approaches attempting to ameliorate the severe effect of drought on plant''s production and to increase the plants tolerance against water deficit for the water economy. In this research, the effect of foliar application of TiO₂, nanoparticles or ordinary TiO₂, on Helianthus annuus subjected to different levels of water deficit was studied. Cell membrane injury increased by increasing the level of water deficit and TiO₂ concentration, and both types of TiO₂ affected the leaves in analogous manner. Ord-TiO₂ increased H₂O₂ generation by 67–240% and lipid peroxidation by 4–67% in leaves. These increases were more than that induced by Nano-TiO₂ and the effect was concentration dependent. Proline significantly increased in leaves by water deficit stress, reaching at 25% field capacity (FC) to more than fivefold compared to that in plants grown on full FC. Spraying plants with water significantly decreased the activities of enzymes in the water deficit stressed roots. The water deficit stress exerted the highest magnitude of effect on the changes of cell membrane injury, MDA, proline content, and activities of CAT and GPX. Nano-TiO₂ was having the highest effect on contents of H₂O₂ and GPX activity. In roots, the level of water deficit causes highest effect on enzyme activities, but TiO₂ influenced more on the changes of MDA and H₂O₂ contents. GPX activity increased by 283% in leaves of plants treated with 50 and 150 ppm Nano-TiO₂, while increased by 170% in those treated with Ord-TiO₂, but APX and CAT activities increased by 17–197%, in average, with Ord-TiO₂. This study concluded that Nano-TiO₂ didn’t ameliorate the effects of drought stress on H. annuus but additively increased the stress, so its use in nano-phytotechnology mustn’t be expanded without extensive studies.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-022-01153-z.     

Designing an immunoinformatic vaccine for peri-implantitis using a structural biology approach

ObjectivesPeri-implantitis is a destructive inflammatory process that affects the soft and hard tissues around dental implants. porphyromonas gingivalis, an anaerobic gram-negative bacterium, appears to be the main culprit. Since there is no efficient and specific vaccine to treat peri-implantitis, the goal of our research has been to develop a multi-epitope vaccination utilizing an immunoinformatics approach that targeted P. gingivalis type I fim A.Materials and methodsP. gingivalis peptides 6JKZ and 6KMF are suitable for vaccine development. B- and T-cell epitopes from 6KMF and 6JKZ were detected and evaluated based on critical factors to produce a multi-epitope vaccine construct. It was assessed based on allergenicity, antigenicity, stability. The vaccine's dual major histocompatibility complex (MHC-I and MHC-II) binding epitopes allowed it to reach a larger population. P. gingivalis fimbriae induce immune subversion through TLR -CXCR4 receptor complex pathway. The ClusPro 2.0 server was used to do the molecular docking using TLR2 - CXCR4 and vaccine epitopes as receptor and ligand respectively.ResultsThe designed vaccine was non-allergenic and had a high antigenicity, solubility, and stability. The 3D structure of the vaccine revealed strong interaction with CXCR4(TLR2) using molecular docking. The vaccine-CXCR4 interface was more consistent, possibly because the vaccination has a higher affinity for the CXCR4-TLR2 complex.ConclusionThis study details the vaccine's distinct and sustained interaction with the CXCR4(TLR2) immunological receptor and its consistent and effective utterance in the bacterial system. As a result, our vaccine formulation will evoke a significant memory response and induce an adaptive immune response against P. gingivalis.     

Haemolymph ecdysteroids in the solitary and gregarious larvae of Schistocerca gregaria

In the penultimate and last instar larvae of Schistocerca gregaria, 20-hydroxyecdysone (20E) makes up 74–84% of detected ecdysteroids in the females, and 63–74% in the males. Remaining ecdysteroids include ecdysone, a compound with HPLC and TLC retention times of makisterone A, and highly polar metabolites. Except for the last instar females, the contents of ecdysone and the unknown compound are higher in the solitary phase, while that of polar metabolites is higher in the gregarious phase. The phases also differ in that the molt-inducing ecdysteroid peaks last longer in the gregarious than in the solitary larvae. Peak concentrations reach 3.0–4.0 μg 20E equiv./ml in penultimate female instar, 2.5–3.0 μg/ml in penultimate male instar, and 1.5–2.0 μg/ml in the last larval instar of both sexes. © 1996 Wiley-Liss, Inc.     

Metabolic regulation analysis of <Emphasis Type="Italic">icd</Emphasis>-gene knockout <Emphasis Type="Italic">Escherichia coli</Emphasis> based on 2D electrophoresis with MALDI-TOF mass spectrometry and enzyme activity measurements

An integrated study of cell growth characteristics, enzyme activities and protein expression patterns was carried out to investigate how the central metabolism of Escherichia coli changes upon knockout of the isocitrate dehydrogenase (ICDH) gene (icd) in the tricarboxylic acid cycle. Deletion of the icd gene led to reduced specific growth rate and reduced specific glucose consumption rate. The reduced specific growth rate in the icd mutant was due mainly to the lower intracellular ATP/ADP ratio as well as to the lower NADPH/NADP⁺ ratio compared with those in the parent strain. However, the specific carbon dioxide evolution rate was found to be higher in the icd mutant strain compared to the parent E. coli. This may be due to the higher activity of 6-phosphogluconate dehydrogenase, phosphoenol pyruvate carboxykinase and NADP⁺-dependent malic enzymes. The glyoxylate pathway was also utilized, as evidenced by the significant upregulation of isocitrate lyase and malate synthase activity in the icd mutant E. coli. The appearance of the glyoxylate pathway caused lower acetate production. Of 21 proteins showing altered expression levels, 17 were successfully identified with the aid of MALDI-TOF mass spectrometry. The results showed that the abolition of ICDH activity significantly affected the respiratory system and electron transport chain, as evidenced by the significant downregulation of proteins encoded by the genes nuoE, nuoH, cydA and cyoA in icd mutant E. coli compared to the parent.     

Ovarian dynamics and their associations with peripheral concentrations of gonadotropins,ovarian steroids,and inhibin during the estrous cycle in goats

Ovarian changes determined by daily transrectal ultrasound and its relationship with FSH, LH, estradiol-17beta, progesterone, and inhibin were investigated in six goats for three consecutive interovulatory intervals. Estrous cycles were synchronized using two injections of prostaglandin F2alpha analogue 11 days apart. All follicles 3 mm or greater in diameter and corpora lutea were measured daily. A follicular wave was defined as one or more follicles growing to 5 mm or greater in diameter. The day that the follicles reached 3 mm in diameter was defined as the day of wave emergence, and the first wave after ovulation was defined as wave 1. During the interovulatory interval (mean +/- SEM, 21.3 +/- 0.4 days; n = 18), follicular waves emerged at 0.3 +/- 0.5, 6.5 +/- 0.2, and 12.1 +/- 0.4 days for wave 1, wave 2, and wave 3, respectively, in goats with three waves of follicular development and at -0.6 +/- 0.3, 4.7 +/- 0.2, 9.4 +/- 0.5, and 13.4 +/- 0.5 days for wave 1, wave 2, wave 3, and wave 4, respectively, in goats with four waves of follicular development (Day 0 = the day of ovulation). The mean diameter of the largest follicle of the ovulatory wave was significantly larger than those of the largest follicles of the other waves. Corpora lutea could be identified ultrasonically at Day 3 postovulation and attained 12.1 +/- 0.3 mm in diameter on Day 8. Transient increases in plasma concentrations of FSH were detected around the day of follicular wave emergence. The level of FSH was negatively correlated with that of inhibin. These results demonstrated that follicular waves occurred in goats and that the predominant follicular wave pattern was four waves with ovulation from wave 4. These results also suggested that the emergence of follicular waves was closely associated with increased secretion of FSH.