Cation Permeability of Voltage-Gated Hair Cell Ca2+ Channels of the Vertebrate Labyrinth

Some hearing, vestibular, and vision disorders are imputable to voltage-gated Ca²⁺ channels of the sensory cells. These channels convey a large Ca²⁺ influx despite extracellular Na⁺ being 70-fold more concentrated than Ca²⁺; such high selectivity is lost in low Ca²⁺, and Na⁺ can permeate. Since the permeation properties and molecular identity of sensory Ca²⁺ channels are debated, in this paper, we examine the Na⁺ current flowing through the L- and R-type Ca²⁺ channels of labyrinth hair cells. Ion currents and cytosolic free Ca²⁺ concentrations were simultaneously monitored in whole-cell recording synchronous to fast fluorescence imaging. L-type and R-type channels were present with different densities at selected sites. In 10 nM Ca²⁺, the activation and deactivation time constants of the L-type Na⁺ current were accelerated and its maximal amplitude increased by 6-fold compared to physiological Ca²⁺. The deactivation of the R-type Na⁺ current was not accelerated, and its current amplitude increased by 2.3-fold in low Ca²⁺; moreover, it was partially blocked by nifedipine in a voltage- and time-dependent manner. In conclusion, L channel gating is affected by the ion species permeating the channel, and its selectivity filter binds Ca²⁺ more strongly than that of R channel; furthermore, external Ca²⁺ prevents nifedipine from perturbing the R selectivity filter.     

Pain Modulation from the Locus Coeruleus in a Model of Hydrocephalus: Searching for Oxidative Stress-Induced Noradrenergic Neuroprotection

Pain transmission at the spinal cord is modulated by noradrenaline (NA)-mediated actions that arise from supraspinal areas. We studied the locus coeruleus (LC) to evaluate the expression of the cathecolamine-synthetizing enzyme tyrosine hydroxylase (TH) and search for local oxidative stress and possible consequences in descending pain modulation in a model of hydrocephalus, a disease characterized by enlargement of the cerebral ventricular system usually due to the obstruction of cerebrospinal fluid flow. Four weeks after kaolin injection into the cisterna magna, immunodetection of the catecholamine-synthetizing enzymes TH and dopamine-β-hydroxylase (DBH) was performed in the LC and spinal cord. Colocalization of the oxidative stress marker 8-OHdG (8-hydroxyguanosine; 8-OHdG), with TH in the LC was performed. Formalin was injected in the hindpaw both for behavioral nociceptive evaluation and the immunodetection of Fos expression in the spinal cord. Hydrocephalic rats presented with a higher expression of TH at the LC, of TH and DBH at the spinal dorsal horn along with decreased nociceptive behavioral responses in the second (inflammatory) phase of the formalin test, and formalin-evoked Fos expression at the spinal dorsal horn. The expression of 8-OHdG was increased in the LC neurons, with higher co-localization in TH-immunoreactive neurons. Collectively, the results indicate increased noradrenergic expression at the LC during hydrocephalus. The strong oxidative stress damage at the LC neurons may lead to local neuroprotective-mediated increases in NA levels. The increased expression of catecholamine-synthetizing enzymes along with the decreased nociception-induced neuronal activation of dorsal horn neurons and behavioral pain signs may indicate that hydrocephalus is associated with alterations in descending pain modulation.     

Lutein: a valuable ingredient of fruit and vegetables

Lutein is a human serum carotenoid which is not synthesized by humans and thus must be obtained by the ingestion of food containing it such as fruits and vegetables. Lutein is present in different forms in those foods as all-trans-lutein, cis-lutein, epoxi-lutein, and lutein linked to proteins. It discusses if the intake of lutein or diets supplemented with lutein or diets rich in fruits and vegetables are important in the prevention of diseases like some cancers, cardiovascular diseases, etc., that may be affected by the antioxidant effect of lutein; or in the prevention of age-related macular degeneration and other eye diseases. The concentration of lutein in fruits and vegetables depends on the species. We've included the concentration of lutein in 74 species reported by different authors since 1990. Currently the quantification of lutein is mainly performed by HPLC, but more investigations into a quantification method for lutein, lutein isomers, and epoxi-lutein are necessary. Improvement of lutein extraction methods is important as well. Methods commonly used in the vegetable and fruit industry like heat treatment, storage conditions, etc. can change lutein concentrations; other factors depend on the plant, for instance the variety, the stage of maturity, etc.     

Effects of SARS-CoV-2 Inflammation on Selected Organ Systems of the Human Body

Introduction and purpose of the study: SARS-CoV-2 virus does not only affect the respiratory system. It may cause damage to many organ systems with long-term effects. The latest scientific reports inform that this virus leaves a long-term trace in the nervous, circulatory, respiratory, urinary and reproductive systems. It manifests itself in disturbances in the functioning of the organs of these systems, causing serious health problems. The aim of the study was to review the latest research into the long-term effects of COVID-19 and determine how common these symptoms are and who is most at risk. Based on a literature review using the electronic scientific databases of PubMed and Web of Science on the long-term effects of SARS-CoV-2 infection, 88 studies were included in the analysis. The information contained in the analyzed literature shows that the SARS-CoV-2 virus can cause multi-organ damage, causing a number of long-term negative health complications. Conclusions: There is evidence that the virus can cause long-term complications lasting more than six months. They mainly concern disturbances in the functioning of the nervous, circulatory and respiratory systems. However, these studies are small or short-lasting, and many are speculative.     

Strain-specific polyketide synthase genes of Aspergillus niger

In silico comparison of 34 putative pks genes in Aspergillus niger strain CBS 513.88 versus A. niger strain ATCC 1015 genome revealed significant nucleotide identity (>95% covering a minimum of 99% of the gene sequence) for 31 of these genes (approximately 91%). A. niger CBS 513.88 harbors three putative pks genes (An01g01130, An11g05940, and An15g07920), for which nucleotide identity was not found in A. niger ATCC 1015. To compare the results of the in silico analysis with the in vivo situation, experimental data were obtained for a large number of A. niger strains obtained from different substrates and geographical regions. Three putative pks genes that were found to be variable between the two A. niger strains using bioinformatics tools were in fact strain-specific genes based on experimental data. The PCR amplification signals for the An01g01130, An11g05940, and An15g07920 pks genes were detected in only 97%, 71%, and 26% of the strains, respectively. Southern blot analyses confirmed the PCR data. Because one of the strain-specific pks genes (An15g07920) is located in a putative ochratoxin cluster, we focused our investigation on that region. We assessed the ochratoxin production capability of the 119 A. niger strains and found a positive association between the presence of this pks gene and the capability of the respective strain to produce ochratoxin.     

The effect of cocoa fermentation and weak organic acids on growth and ochratoxin A production by Aspergillus species

The acidic characteristics of cocoa beans have influence on flavor development in chocolate. Cocoa cotyledons are not naturally acidic, the acidity comes from organic acids produced by the fermentative microorganisms which grow during the processing of cocoa. Different concentrations of these metabolites can be produced according to the fermentation practices adopted in the farms, which could affect the growth and ochratoxin A production by fungi. This work presents two independent experiments carried out to investigate the effect of some fermentation practices on ochratoxin A production by Aspergillus carbonarius in cocoa, and the effect of weak organic acids such as acetic, lactic and citric at different pH values on growth and ochratoxin A production by A. carbonarius and Aspergillus niger in culture media. A statistical difference (ρ<0.05) in the ochratoxin A level in the cured cocoa beans was observed in some fermentation practices adopted. The laboratorial studies demonstrate the influence of organic acids on fungal growth and ochratoxin A production, with differences according to the media pH and the organic acid present. Acetic acid was the most inhibitory acid against A. carbonarius and A. niger. From the point of view of food safety, considering the amount of ochratoxin A produced, fermentation practices should be conducted towards the enhancement of acetic acid, although lactic and citric acids also have an important role in lowering the pH to improve the toxicity of acetic acid.     

Microbiological characterization of randomly selected Portuguese raw milk cheeses with reference to food safety

Seventy raw milk cheeses made in different regions of Portugal, both hard and soft varieties, made with cow's, ewe's, or goat's milk or combinations of these, were sampled within their quoted shelf lives for microbiological safety. On the basis of the presence or numbers of Escherichia coli, E. coli O157, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, cheeses were categorized as satisfactory, acceptable, unsatisfactory, or unacceptable and potentially hazardous. Twenty-two of the 70 cheeses were classified as satisfactory or acceptable. Thirty-seven of the cheeses were considered unsatisfactory because of the presence of E. coli, S. aureus, or both, while 11 of the cheeses were graded as unacceptable and potentially hazardous because of the presence of excessive numbers of S. aureus, E. coli, or L. monocytogenes and the presence of Salmonella in three of these. All cheeses graded as unacceptable and potentially hazardous were soft or semisoft cheeses made with ewe's and goat's milk, with the exception of two hard cheeses made with cow's milk. E. coli O157 was not detected in any of the cheeses. According to the present results, it seems that the presence or counts of pathogenic or indicator organisms in raw milk cheeses cannot be related to the processing conditions, milk type, or region of production.     

Ternary Biopolymer Based on Wheat Gluten,Whey Protein Concentrate and Montmorillonite

The aim of the research was to obtain biopolymers based on wheat gluten, whey protein concentrate (WPC) and montmorillonite (MON). Ternary biopolymers were formed as heat-induced gels and they were hardened by water evaporation. Adding 7 % of MON and 5 % WPC to gluten caused ca. four times higher values of storage modulus. Increased moduli values with adding MON and WPC to gluten were probably caused by reinforcing effect of MON, which decreased mobility of gluten chains and possible interactions between gluten and whey proteins by disulphide interchange. Increase in gluten protein concentration and addition of WPC and MON caused increase in viscosity measured by dissipation of ultrasound vibrations. Evaporation of water from the gels formed very hard material with high puncture force values. Obtained gels were very plastic and it was easy to form any type of shapes. They could be used to produce biodegradable pottery (e.g. flowerpots) with the mechanical properties similar to non-degradable clay products.