Investigation of the Effect of Some Optically Active Imine Compounds on the Enzyme Activities of hCA‐I and hCA‐II under In Vitro Conditions: An Experimental and Theoretical Study

Inhibitors of carbonic anhydrase (hCA; EC 4.2.1.1) are used as medicines for many diseases. Therefore, they are very important. In this study, a known series of Schiff bases were synthesized and their effects on the activities of hCA‐I and hCA‐II, which are cytosolic isoenzymes of carbonic anhydrase, were investigated under in vitro conditions. The synthesized compounds (H1, H2, H3, and H4) were found to cause inhibition on enzyme activities of hCA‐1 and hCA‐II. IC₅₀ values of H1, H2, H3, and H4 compounds were 140, 88, 201, and 271 μM for hCA‐I enzyme activity and 134, 251, 79, and 604 μM for hCA‐II enzyme activity, respectively. The synthesized Schiff bases were characterized by several methods, including ¹H NMR, FT‐IR, elemental analysis, and polarimetric measurements. Correlation coefficient square values (R²) of comparison of the theoretical and experimental ¹H NMR shifts for H1, H2, H3, and H4 compounds were found as 0.9781, 0.9814, 0.9758, and 0.8635, respectively.     

An update comprehensive review on the status of COVID-19: vaccines,drugs, variants and neurological symptoms

Various recently reported mutant variants, candidate and urgently approved current vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many current situations with severe neurological damage and symptoms as well as respiratory tract disorders have begun to be reported. In particular, drug, vaccine, and neutralizing monoclonal antibodies (mAbs) have been developed and are currently being evaluated in clinical trials. Here, we review lessons learned from the use of novel mutant variants of the COVID-19 virus, immunization, new drug solutions, and antibody therapies for infections. Next, we focus on the B 1.1.7, B 1.351, P.1, and B.1.617 lineages or variants of concern that have been reported worldwide, the new manifestations of neurological manifestations, the current therapeutic drug targets for its treatment, vaccine candidates and their efficacy, implantation of convalescent plasma, and neutralization of mAbs. We review specific clinical questions, including many emerging neurological effects and respiratory tract injuries, as well as new potential biomarkers, new studies in addition to known therapeutics, and chronic diseases of vaccines that have received immediate approval. To answer these questions, further understanding of the burden kinetics of COVID-19 and its correlation with neurological clinical outcomes, endogenous antibody responses to vaccines, pharmacokinetics of neutralizing mAbs, and action against emerging viral mutant variants is needed.     

A validated antibody panel for the characterization of tau post-translational modifications

Background

Tau is a microtubule-binding protein, which is subject to various post-translational modifications (PTMs) including phosphorylation, methylation, acetylation, glycosylation, nitration, sumoylation and truncation. Aberrant PTMs such as hyperphosphorylation result in tau aggregation and the formation of neurofibrillary tangles, which are a hallmark of Alzheimer’s disease (AD). In order to study the importance of PTMs on tau function, antibodies raised against specific modification sites are widely used. However, quality control of these antibodies is lacking and their specificity for particular modifications is often unclear.

Methods

In this study, we first designed an online tool called ‘TauPTM’, which enables the visualization of PTMs and their interactions on human tau. Using TauPTM, we next searched for commercially available antibodies against tau PTMs and characterized their specificity by peptide array, immunoblotting, electrochemiluminescence ELISA and immunofluorescence technologies.

Results

We demonstrate that commercially available antibodies can show a significant lack of specificity, and PTM-specific antibodies in particular often recognize non-modified versions of the protein. In addition, detection may be hindered by other PTMs in close vicinity, complicating the interpretation of results. Finally, we compiled a panel of specific antibodies and show that they are useful to detect PTM-modified endogenous tau in hiPSC-derived neurons and mouse brains.

Conclusion

This study has created a platform to reliably and robustly detect changes in localization and abundance of post-translationally modified tau in health and disease. A web-based version of TauPTM is fully available at http://www.tauptm.org.

     

Single-stage photofermentative biohydrogen production from sugar beet molasses by different purple non-sulfur bacteria

Bioprocess and Biosystems Engineering - Biohydrogen production via fermentative routes offers considerable advantages in waste recycling and sustainable energy production. This can be realized by...     

Life-cycle and foraging patterns of native <Emphasis Type="Italic">Bombus terrestris</Emphasis> (L.) (Hymenoptera,Apidae) in the Mediterranean region

Life-cycle and foraging patterns of native Bombus terrestris populations were investigated at two sites in the Mediterranean region of Turkey, Phassalis (0 – 100 m above sea level [a.s.l.]) and Termessos (500 – 700 m a.s.l.). Bumble-bee activity was recorded during standard bee walks from November 2003 until the end of October 2004, each site being visited three times every month during the one-year period. The yearly dynamics of flight, the flowering plant species visited, and the visitation frequencies of these plants were recorded during every bee walk at both sites. There were considerable differences between the two populations with regard to the dates when the queens emerged from diapause (the emerging season), the timing of the appearance of sexuals (young queens and males), and the total number of plant species visited. Bombus terrestris queens emerged from diapause in November-December at the Phassalis site (coastal area) and in February-March at the Termessos site. The queens aestivated at the Phassalis site, whereas they hibernated at the Termessos site. Only one generation per year was produced at each site. The duration of the queens’ diapause lasted 5 – 8 months and length of the life cycle 190 – 215 days. Native B. terrestris populations were noted to forage on 47 flowering plant species from 20 families (10 at the Phassalis site and 40 at the Termessos site) during the study period. Two of the plant species (Arbutus unedo L. and Vitex agnus-castus L.) have long flowering periods and play a crucial role in the life cycle of native B. terrestris populations. The emergence of queens at the aestivation site was synchronized with the flowering of Arbutus unedo L., while the emergence of sexuals coincided with the flowering of Vitex agnus-castus L. at both sites. Received 30 May 2007; revised 5 December 2007; accepted 8 January 2008.     

The chromate-inducible chrBACF operon from the transposable element TnOtChr confers resistance to chromium(VI) and superoxide

Large-scale industrial use of chromium(VI) has resulted in widespread contamination with carcinogenic chromium(VI). The abilities of microorganisms to survive in these environments and to detoxify chromate require the presence of specific resistance systems. Here we report identification of the transposon-located (TnOtChr) chromate resistance genes from the highly tolerant strain Ochrobactrum tritici 5bvl1 surviving chromate concentrations of >50 mM. The 7,189-bp-long TnOtChr of the mixed Tn21/Tn3 transposon subfamily contains a group of chrB, chrA, chrC, and chrF genes situated between divergently transcribed resolvase and transposase genes. The chrB and chrA genes, but not chrF or chrC, were essential for establishment of high resistance in chromium-sensitive O. tritici. The chr promoter was strongly induced by chromate or dichromate, but it was completely unresponsive to Cr(III), oxidants, sulfate, or other oxyanions. Plasmid reporter experiments identified ChrB as a chromate-sensing regulator of chr expression. Induction of the chr operon suppressed accumulation of cellular Cr through the activity of a chromate efflux pump encoded by chrA. Expression of chrB, chrC, or chrF in an Escherichia coli sodA sodB double mutant restored its aerobic growth in minimal medium and conferred resistance to superoxide-generating agents menadione and paraquat. Nitroblue tetrazolium staining on native gels showed that ChrC protein had superoxide dismutase activity. TnOtChr appears to represent a mobile genetic system for the distribution of the chromate-regulated resistance operon. The presence of three genes protecting against superoxide toxicity should provide an additional survival advantage to TnOtChr-containing cells in the environments with multiple redox-active contaminants.     

In Vitro Regeneration of Achillea millefolium L from Shoot-tips and Root Segments of Seedlings

This report describes, for the first time, an efficient plant regeneration system for Achillea millefolium L (yarrow), a medicinal plant, via shoot multiplication from shoot-tips and adventitious shoot regeneration from root segments. Higher numbers of shoots were obtained when shoot-tips were cultured on MSMO medium supplemented with 3.0 mg l^?1 BA and 0.5 mg l^?1 IAA, or 5.0 mg l^?1 KIN and 1.0 mg l^?1 IBA, producing 17.3 and 17.0 shoots per explant at 100% frequency, respectively. For adventitous shoot regeneration, only root segments developed shoots when cultured on medium containing a combination of 1 mg l^?1 TDZ, 0.5 mg l^?1 IAA and 0.5 mg l^?1 GA3 (18.9 shoots per explant at 100% frequency), while other types of explants (i.e., cotyledons, leaf lamina and petiole segments) or hormonal combinations tested were found ineffective. Regenerated shoots rooted readily on MSMO medium containing different concentrations of IAA, IBA, NAA or 2,4-D, however, NAA at 0.5 mg l^?1, or IBA at 0.5 or 1.0 mg l^?1 were found to be the most productive. Nearly all of the regenerated plants (98%) survived through the hardening process when the rooted plantlets were kept at 55–65% relative humidity for 2 weeks, which were then planted in pots containing potting soil and kept at 25–35% humidity.     

Binding of Plasma Membrane Lipids Recruits the Yeast Integral Membrane Protein Ist2 to the Cortical ER

Recruitment of cytosolic proteins to individual membranes is governed by a combination of protein–protein and protein–membrane interactions. Many proteins recognize phosphatidylinositol 4,5-bisphosphate [PI(4,5)P₂] at the cytosolic surface of the plasma membrane (PM). Here, we show that a protein–lipid interaction can also serve as a dominant signal for the sorting of integral membrane proteins. Interaction with phosphatidly-inositolphosphates (PIPs) at the PM is involved in the targeting of the polytopic yeast protein Ist2 to PM-associated domains of the cortical endoplasmic reticulum (ER). Moreover, binding of PI(4,5)P₂ at the PM functions as a dominant mechanism that targets other integral membrane proteins to PM-associated domains of the cortical ER. This sorting to a subdomain of the ER abolishes proteasomal degradation and trafficking along the classical secretory (sec) pathway. In combination with the localization of IST2 mRNA to the bud tip and other redundant signals in Ist2, binding of PIPs leads to efficient accumulation of Ist2 at domains of the cortical ER from where the protein may reach the PM independently of the function of the sec-pathway.     

Neutral sphingomyelinase inhibition alleviates apoptosis,but not ER stress,in liver ischemia–reperfusion injury

Previous studies have revealed the activation of neutral sphingomyelinase (N-SMase)/ceramide pathway in hepatic tissue following warm liver ischemia reperfusion (IR) injury. Excessive ceramide accumulation is known to potentiate apoptotic stimuli and a link between apoptosis and endoplasmic reticulum (ER) stress has been established in hepatic IR injury. Thus, this study determined the role of selective N-SMase inhibition on ER stress and apoptotic markers in a rat model of liver IR injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60?min, followed by 60?min reperfusion. Levels of sphingmyelin and ceramide in liver tissue were determined by an optimized multiple reactions monitoring (MRM) method using ultrafast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Spingomyelin levels were significantly increased in all IR groups compared with controls. Treatment with a specific N-SMase inhibitor significantly decreased all measured ceramides in IR injury. A significant increase was observed in ER stress markers C/EBP-homologous protein (CHOP) and 78?kDa glucose-regulated protein (GRP78) in IR injury, which was not significantly altered by N-SMase inhibition. Inhibition of N-SMase caused a significant reduction in phospho-NF-kB levels, hepatic TUNEL staining, cytosolic cytochrome c, and caspase-3, -8, and -9 activities which were significantly increased in IR injury. Data herein confirm the role of ceramide in increased apoptotic cell death and highlight the protective effect of N-SMase inhibition in down-regulation of apoptotic stimuli responses occurring in hepatic IR injury.     

The Correlation of Serum Trace Elements and Heavy Metals with Carotid Artery Atherosclerosis in Maintenance Hemodialysis Patients

Changes in essential trace elements and heavy metals may affect the atherosclerotic state of patients on maintenance hemodialysis (HD). The aim of the study was to evaluate the relation between the serum levels of some trace elements and heavy metals (iron, zinc, manganese, copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio) and carotid artery intima-media thickness (CIMT) in HD patients. Fifty chronic HD patients without known atherosclerotic disease and 48 age- and sex-matched healthy individuals were included in the study. The serum levels of trace elements (iron, zinc, manganese, copper, and magnesium) and heavy metals (cobalt, cadmium, and lead) were measured by Atomic Adsorption Spectrophotometer (UNICAM-929). CIMT was assessed by carotid artery ultrasonography. The serum levels of iron, zinc, and manganese were lower; levels of copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio were higher in HD patients compared to controls. CIMT in HD patients were higher than the control group (0.64?±?0.11 vs 0.42?±?0.05, p?相似文献