Phosphatidylserine Membrane Translocation in Human Spermatozoa: Topography in Membrane Domains and Relation to Cell Vitality

The complex structure of the human spermatozoa membrane comprises five topographic domains. Transmembrane asymmetry of the distribution of phospholipids including phosphatidylserine (PS) is considered a marker of cell activity. The objective of the study was to determine which cytomembrane domains of human spermatozoa are involved in PS membrane translocation and to identify the possible relationship of PS translocation with spermatozoa morphology and vitality. In normozoospermic semen of 35 donors, annexin-V labeling with fluorescein determined PS translocation. Propidium iodide staining distinguished between vital and dead spermatozoa. Three types of PS membrane translocation have been distinguished: (1) in the midpiece, (2) in the acrosomal part and (3) simultaneously in the midpiece and acrosomal part. In morphologically normal vital spermatozoa, PS translocation occurred in the midpiece but never in the equatorial region. In dead spermatozoa, simultaneous PS translocation in the midpiece and acrosomal part was most often observed. The difference between proportions of, respectively, vital and dead spermatozoa presenting PS translocation located in different domains was significant (P < 0.0001). In vital cells, there was no difference in PS translocation prevalence between morphologically normal and abnormal spermatozoa (P > 0.05). The strict relation of PS translocation to specific membrane domains indicates functional specificity. It seems doubtful to include this phenomenon in physiological mechanisms of elimination of abnormal spermatozoa

Photochemical Degradation of Disazo Dyes, R-Salt Derivatives, on Dyed Cotton

Direct disazo dyes, R-salt derivatives, were synthesized and examined. The dyes were prepared by coupling of appropriate components with tetrazotized diacyl derivatives of aromatic diamines. Derivatives of dicarboxylic acids with the general formula HOOC―(CH2)n―COOH (n = 0 ÷ 4) were used as acylating agents. Photochemical degradation rates of dyes on dyed cotton fabric were studied. Compositions of azo-hydrazone tautomers, their aggregates, and their decay rates in UV-Vis light were determined. It was assumed that the length of aliphatic chain in the molecule affects the rate of its photochemical degradation T1/2, tautomeric composition, and dyes aggregation in azo and hydrazo forms

Fluctuations of Otoacoustic Emissions and Medial Olivocochlear Reflexes: Tracking One Subject over a Year

The purpose of the study was to measure the variability of transiently evoked otoacoustic emissions (TEOAEs) and the medial olivocochlear reflex (MOCR) over a long period of time in one person. TEOAEs with and without contralateral acoustic stimulation (CAS) by white noise were measured, from which MOCR strength could be derived as either a dB or % change. In this longitudinal case study, measurements were performed on the right and left ears of a young, normally hearing adult female once a week for 1 year. The results showed that TEOAE level and MOCR strength fluctuated over the year but tended to remain close to a baseline level, with standard deviations of around 0.5 dB and 0.05 dB, respectively. The TEOAE latencies at frequencies from 1 to 4 kHz were relatively stable, with maximum changes ranging from 0.5 ms for the 1 kHz band to 0.08 ms for the 4 kHz band. TEOAE levels and MOCR strengths were strongly and negatively correlated, meaning that the higher the TEOAE level, the lower the MOCR. Additionally, comparison of fluctuations between the ears revealed positive correlation, i.e., the higher the TEOAE level or MOCR in one ear, the higher in the second ear

The Reliability of Contralateral Suppression of Otoacoustic Emissions Is Greater in Women than in Men

The aim of this study was to compare the reliability of the medial olivocochlear reflex (MOCR) between men and women. The strength of the MOCR was measured in terms of the suppression of transiently evoked otoacoustic emissions (TEOAEs) by contralateral acoustic stimulation (CAS). The difference between TEOAEs with and without CAS (white noise) was calculated as raw decibel TEOAE suppression as well as normalized TEOAE suppression expressed in percent. In each subject, sets of measurements were performed twice. Reliability was evaluated by calculating the intraclass correlation coefficient, the standard error of measurement, and the minimum detectable change (MDC). The study included 40 normally hearing subjects (20 men; 20 women). The estimates of MOCR for both genders were similar. Nevertheless, the reliability of the MOCR was poorer in men, with an MDC around twice that of women. This can be only partially attributed to slightly lower signal-to-noise ratios (SNRs) in men, since we used strict procedures calling for high SNRs (around 20 dB on average). Furthermore, even when we compared subgroups with similar SNRs, there was still lower MOCR reliability in men

Taxonomic review and microbial ecology in bacterial nanocellulose fermentation

Acetic acid bacteria (AAB) have a long history of use in several fermentation processes. Their exploitation gradually emerged in biotechnologic applications, especially in the biosynthesis of useful chemicals and processes for the manufacture of several fermented food products. Taxonomic studies, from traditional to polyphasic approaches, have gradually allowed the proper classification of several ABB into distinct genera and species, among them, the bacterial nanocellulose (BNC) producers, notably Komagataeibacter xylinus. Despite the advantages in using specific (isolated) strains for biotechnologic processes toward controlling the kinetics and process yield, mixed culture fermentations may provide an interesting approach to tailoring the properties of BNC and to increase the product yield when aiming at industrial scale. Microbial population dynamics may play a synergistic role in the coordinative substrate consumption and metabolites production, especially if using complex media (as is the case with low cost substrates, eg, residues from other processes). This chapter will first review the main historic steps involved in the taxonomic classification of AAB. It will then address the lying potential behind mixed microbial fermentations, from kombucha to nata de coco, both sharing in common, the contribution of cellulose-producing bacteria for the fermentation process.(undefined

Effect of the COVID-19 Pandemic on Resting-State Brain Activity in Individuals with Tinnitus

This study looked at the possible effect of the COVID-19 pandemic on individuals who came to our clinic seeking relief from tinnitus. The performance of the subjects during the COVID-19 pandemic was compared with similar individuals who came to our clinic before the pandemic began. The study involved 50 adults with chronic tinnitus, made up of a study group (24 subjects tested during the COVID-19 pandemic of 2020–2021) and a control group before the pandemic began (26 subjects tested from 2013 to 2017). None of the 24 reported having contracted COVID-19. Data collection involved the Tinnitus Handicap Inventory (THI) questionnaire, audiological tests, and quantitative electroencephalography (qEEG). In terms of THI scores, there were no statistically significant differences between the two groups. However, with regard to qEEG, some changes were observed, with significant decreases in alpha and beta band activity in the study group compared to the control group, particularly over the auditory cortex. We conclude that COVID-19 did not have a discernible impact on the general well-being of individuals with tinnitus. However, it did appear to alter brain activity, specifically in the alpha and beta bands over the auditory cortex, and these reults warrant further investigation

Promising approaches for the assembly of the catalytically active, recombinant Desulfomicrobium baculatum hydrogenase with substitutions at the active site

Abstract Background Hydrogenases (H2ases) are metalloenzymes capable of the reversible conversion of protons and electrons to molecular hydrogen. Exploiting the unique enzymatic activity of H2ases can lead to advancements in the process of biohydrogen evolution and green energy production. Results Here we created of a functional, optimized operon for rapid and robust production of recombinant [NiFe] Desulfomicrobium baculatum hydrogenase (Dmb H2ase). The conversion of the [NiFeSe] Dmb H2ase to [NiFe] type was performed on genetic level by site-directed mutagenesis. The native dmb operon includes two structural H2ase genes, coding for large and small subunits, and an additional gene, encoding a specific maturase (protease) that is essential for the proper maturation of the enzyme. Dmb, like all H2ases, needs intricate bio-production machinery to incorporate its crucial inorganic ligands and cofactors. Strictly anaerobic, sulfate reducer D. baculatum bacteria are distinct, in terms of their biology, from E. coli. Thus, we introduced a series of alterations within the native dmb genes. As a result, more than 100 elements, further compiled into 32 operon variants, were constructed. The initial requirement for a specific maturase was omitted by the artificial truncation of the large Dmb subunit. The assembly of the produced H2ase subunit variants was investigated both, in vitro and in vivo. This approach resulted in 4 recombinant [NiFe] Dmb enzyme variants, capable of H2 evolution. The aim of this study was to overcome the gene expression, protein biosynthesis, maturation and ligand loading bottlenecks for the easy, fast, and cost-effective delivery of recombinant [NiFe] H2ase, using a commonly available E. coli strains. Conclusion The optimized genetic constructs together with the developed growth and purification procedures appear to be a promising platform for further studies toward fully-active and O2 tolerant, recombinant [NiFeSe] Dmb H2ase, resembling the native Dmb enzyme. It could likely be achieved by selective cysteine to selenocysteine substitution within the active site of the [NiFe] Dmb variant