Jarmila Zídková

Autophagy inhibition in early but not in later stages prevents 3T3-L1 differentiation: Effect on mitochondrial remodeling.

Autophagy is essential for successful white adipocyte differentiation but the data regarding the timing and relevance of autophagy action during different phases of adipogenesis are limited. We subjected 3T3-L1 preadipocytes to a standard differentiation protocol and inhibited the autophagy within time-limited periods (days 0-2; 2-4; 4-6; 6-8) by asparagine or 3-methyladenine. In the normal course of events, both autophagy flux and the mRNA expression of autophagy related genes (Atg5, Atg12, Atg16, beclin 1) is most intensive at the beginning of differentiation (days 0-4) and then declines. The initiation of differentiation is associated with a 50% reduction of the mitochondrial copy number on day 2 followed by rapid mitochondrial biogenesis. Preadipocytes and differentiated adipocytes differ in the mRNA expression of genes involved in electron transport (Nufsd1, Sdhb, Uqcrc1); ATP synthesis (ATP5b); fatty acid metabolism (CPT1b, Acadl); mitochondrial transporters (Hspa9, Slc25A1) and the TCA cycle (Pcx, Mdh2) as well as citrate synthase activity. Autophagy inhibition during the first two days of differentiation blocked both phenotype changes (lipid accumulation) and the gene expression pattern, while having no or only a marginal effect over any other time period. Similarly, autophagy inhibition between days 0-2 inhibited mitotic clonal expansion as well as mitochondrial network remodeling. In conclusion, we found that autophagy is essential and most active during an initial stage of adipocyte differentiation but it is dispensable during its later stages. We propose that the degradation of preadipocyte cytoplasmic structures, predominantly mitochondria, is an important function of autophagy during this phase and its absence prevents remodeling of the mitochondrial gene expression pattern and mitochondrial network organization.

SsrA genes of streptomycetes and association of proteins to the tmRNA during development and cellular differentiation

Transfer‐messenger RNA (tmRNA, 10Sa RNA, ssrA) is bacterial RNA having both tRNA and mRNA properties and playing an essential role in recycling of 70S ribosomes that are stalled on defective mRNA. The trans‐translational system is thought to play a crucial role in bacterial survival under adverse conditions. Streptomycetes are Gram‐positive soil bacteria exposed to various physical and chemical stresses that activate specialized responses such as synthesis of antibiotics and morphological differentiation. Comparative sequence analysis of ssrA genes of streptomycetes revealed the most significant differences in the central parts of tag‐reading frames, in the stop codons and in the 15–34 nucleotide sequences following stop codons. A major challenge in understanding the interactions that control the function of tmRNA is the definition of protein interactions. Proteins from various phases of development of Streptomyces aureofaciens associated with tmRNA were analyzed. Using affinity chromatography on tmRNA‐Sepharose and photo cross‐linking experiments with [32P]labeled tmRNA seven proteins, the β and β′‐subunits of DNA dependent RNA polymerase, polyribonucleotide nucleotidyltransferase (PNPase), ribosomal protein SS1, ATP‐binding cassette transporters, elongation factor Tu, and SmpB were identified among the proteins associated with tmRNA of S. aureofaciens. We examined the functional role of ribosomal protein SS1 in a defined in vitro trans‐translation system. Our data show that the protein SS1 that structurally differs from S1 of Escherichia coli is required for translation of the tmRNA tag‐reading frame.

A new allergen family involved in pollen food-associated syndrome: Snakin/gibberellin-regulated proteins

At least two pollen food associated syndromes were described with cypress pollen allergy involving peach and citrus. Snakin/gibberellin regulated proteins are described herein to be the cross-reactive allergens between Cupressus sempervirens pollen and fruit/vegetables.

6S RNA modulates growth and antibiotic production in Streptomyces coelicolor

The aim of this study was to contribute to clarifying the role of 6S RNA in the development and control of antibiotic biosynthesis in Streptomyces coelicolor. Due to the low energetic cost of gene silencing via 6S RNA, it is an easy and rapid means of down-regulating the expression of specific genes in response to signals from changes in the environment. The expression of 6S RNA in S. coelicolor is not constitutive, and its accumulation is adapted to changes in nutritional conditions. The 6S RNA of S. coelicolor is capable of interacting with RNA polymerase β β′ subunits and is a template for the transcription of short pRNAs. Deletion of the ssrS gene from S. coelicolor affects the growth rate and causes changes in the expression of several pathway-specific genes involved in actinorhodin biosynthesis. The complementation of the ΔssrS strain with ssrS gene restored the wild-type levels of growth and actinorhodin production. We conclude that 6S RNA contributes to the optimization of cellular adaptation and is an important factor involved in the regulation of growth and expression of key genes for the biosynthesis of actinorhodin.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species—A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.

Cypress Pollinosis: from Tree to Clinic.

Cypress (Cupressus sp.pl) is a genus within the Cupressaceae family. This family covers all of the Earth’s continents except for Antarctica, and it includes about 160 species. The most important taxa for allergic diseases belong to five different genera: Cupressus, Hesperocyparis, Juniperus, Cryptomeria, and Chamaecyparis. Cupressaceae species share a common pollen type that can even include the genus Taxus (Taxaceae) when this plant is also present. As Juniperus oxycedrus pollinates in October, Cupressus sempervirens in January and February, Hesperocyparis arizonica (prev. Cupressus arizonica) in February and March, and Juniperus communis in April, the symptomatic period is long-lasting. Due to global warming, the pollination period tends to last longer, and there is a trend for Cupressaceae bioclimate niches to migrate north. In Mediterranean areas, C. sempervirens (Italian cypress or Mediterranean cypress) is by far the most common pollinating species. It accounts for half of the total pollination level. The group 1 major allergens belong to the pectate-lyase family, and members share 70 to 97% sequence homology within the different Cupressaceae. Group 2 allergens correspond to the polygalacturonase protein family, while group 3, a minor allergen, belongs to the family of “thaumatin-like proteins,” a pathogenesis-related protein 5. Group 4 allergens are Ca++-binding protein (4 EF-hands). Aside from these four groups, about 15 other allergens have been reported. Prominent among these is a basic low-molecular mass cross-reactive allergen that was identified recently, and which is suspected to be involved in pollen food syndromes which are common with peach and citrus. The prevalence of cypress allergy in the general population ranges from 0.6 to 3%, depending on the degree of exposure to the pollen. Depending on the geographic area and the studied population, 9 to 65% of outpatients consulting an allergist may have sensitization to cypress pollen. Repeated cross-sectional studies performed at different time intervals have demonstrated a threefold increase in the percentage of cypress allergy around the Mediterranean area. Risk factors include a genetic predisposition and/or a strong exposure to pollen, and the natural history of cypress allergy allows identification of a subgroup of patients as allergic rather than atopic. Concerning the clinical expression, rhinitis is the most prevalent symptom, while conjunctivitis is the most disabling. Pharmacological treatment of cypress allergies is not different from that of other seasonal allergies. Immunotherapy has been used, initially by subcutaneous injections, but currently mostly through the sublingual route. Although clinical trials have included only a limited number of patients, it has proven effective and safe. Avoidance can be implemented at the individual level, as well as at the community level, through the use of alternative plants, low-pollinating cypresses, or by trimming hedges before pollination.

Effect of selenium-enriched defatted rape seeds on tissue cadmium and essential elements utilization in rats

The effect of selenium-enriched defatted rapeseeds (DRS) added to the diet on Se uptake by rat organisms (whole blood, liver, kidney) was investigated in model conditions. Additionally, the response of other essential trace and major mineral elements (Cu, Ca, Fe, K, Mg, Mn, P, S, and Zn) in rat organisms on selenium and/or DRS addition was assessed. The experimental diets for the individual experimental groups were prepared as follows: group DRS 0 (control diet), group DRS 30 (30% of soybean meal in the diet replaced with DRS), group DRS60 (60% of soybean meal in the diet replaced with DRS), and group DRS100 (100% of soybean meal in the diet replaced with DRS), either unenriched or naturally fortified with Se. Whereas Se content in the blood and liver of the animals remained unchanged, increased Se levels were observed in kidney of the selenized DRS100 group compared to the others. Moreover, the results showed decreasing Cd content in the rat liver with increasing Se content in the diet, confirming antagonism of these elements. Concerning the essential elements, the application of the selenized DRS did not result in any serious imbalance in the utilization of these elements. In contrast, Se addition seems to be helpful for the improved utilization of essential elements such as P, S, and Zn, compared to the DRS-containing diet without Se fortification.

Nano-selenium and its nanomedicine applications: a critical review

Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration.

The Response of Macro- and Micronutrient Nutrient Status and Biochemical Processes in Rats Fed on a Diet with Selenium-Enriched Defatted Rapeseed and/or Vitamin E Supplementation

The response of nutrient status and biochemical processes in (i) Wistar and (ii) spontaneously hypertensive (SHR) rats upon dietary intake of selenium- (Se-) enriched defatted rapeseed (DRS) and/or vitamin E fortification was examined to assess the health benefit of DRS in animal nutrition. Twenty-four individuals of each type of rat were used: The control group was fed with an untreated diet (Diet A). In Diets B and C, soybean meal was replaced with defatted DRS, which comprised 14% of the total diet. The selenized DRS application resulted in ~3-fold increase of Se content in the diet. Diet C was also fortified with the addition of vitamin E, increasing the natural content by 30%. The Se content of the blood and kidneys tended to increase in the DRS groups, where the changes were significant (P < 0.05) only in the case of SHR rats. The iodine (I) content and the proportion of iodide in rat livers indicated a lower transformation rate of iodide into organoiodine compounds compared to the control. Slight and ambiguous alterations in the antioxidative response of the rat were observed in the DRS groups, but the addition of vitamin E to the diet helped to moderate these effects.

Immunodominant Semen Proteins III: IgG 1 and IgG 4 Linkage in Female Immune Infertility

Active immune mechanism in the female reproductive tract may produce high levels of anti-seminal/sperm antibodies. Generated antibodies in the process of isoimmunization seem to be associated with female immune infertility. The aim of our study consists in the profiling of specific serum immunoglobulin classes and subclasses in infertile women. We focus on the distribution of serum seminal/sperm-specific antibodies in order to find those apparently related to female isoimmunization. Immunoglobulins G1-4, A1,2, M and E were measured by ELISA in serum from 30 infertile and 10 fertile females. Anti-seminal/sperm IgG1 and IgG4 fractions were predominantly detected. Anti-seminal IgG1 and IgG4 were observed approximately in the 2:1 ratio, anti-sperm fraction in the 1:2 ratio. Strikingly, the approximate ratio between IgG1 and IgG2 was 3:1 in seminal specific and 2:1 in sperm specific antibodies. Surprisingly, IgG3 antibodies were nearly negative for both antigen fractions, seminal and sperm. Concerning our results, the proportionality does exist between seminal and sperm antibody fractions. Based on the poorly detectable levels of semen specific IgE, M, A1,2, G3, the markers of pathologic female isoimmunization appear to be the serum IgG1 and IgG4. These preliminary findings may contribute to a detailed patient diagnosis and an improved therapy.