Umut Şahar

Purpose: The aim of this study was to investigate the dynamic changes in sialic acid composition during embryonic development of the sea urchin Paracentrotus lividus (P. lividus) and to evaluate stage-specific variations in sialic acid composition.Method: Sialic acid variants were analyzed in unfertilized eggs and embryos at the fertilized egg, 4-cell, 128-cell, blastula, gastrula, and pluteus stages using capillary LC–ESI–MS/MS following DMB derivatization. Relative abundances were determined from the peak areas of LC–ESI–MS/MS MRM chromatograms. Statistical differences among developmental stages were evaluated using one-way ANOVA followed by Tukey's multiple comparisons test.Findings: Seven sialic acid species, including Neu5Ac, Neu5Gc, and five O-acetylated derivatives, were identified throughout embryonic development. Neu5Gc was the predominant sialic acid in unfertilized eggs and exhibited a significant reduction immediately after fertilization (P < 0.0001), followed by a transient increase during early cleavage and blastula stages before declining markedly in gastrula and pluteus embryos. Neu5Ac remained relatively stable throughout early development but decreased significantly at the pluteus stage (P < 0.001). Several O-acetylated sialic acid derivatives displayed distinct stage-specific abundance patterns, indicating dynamic remodeling of sialic acid composition during embryogenesis.Conclusion: These findings demonstrate that sialic acid composition is developmentally regulated during P. lividus embryogenesis. The stage-specific alterations in Neu5Gc, Neu5Ac, and their O-acetylated derivatives suggest coordinated regulation of sialylation during early embryonic development and provide a foundation for future studies investigating the functional roles of sialic acid modifications in developmental processes.

The implementation of nanotechnology in pulmonary delivery systems might result in better and more specific therapy. Therefore, a nano-sized drug carrier should be toxicologically inert and not induce adverse effects. We aimed to investigate the responses of a polymer nano drug carrier, a lysine poly-hydroxyethyl methacrylate nanoparticle (NP) [Lys-p(HEMA)], loaded with formoterol, both in vitro and in vivo in an ovalbumin (OVA) asthma model. The successfully synthesized nanodrug formulation showed an expectedly steady in vitro release profile. There was no sign of in vitro toxicity, and the 16HBE and THP-1 cell lines remained vital after exposure to the nanocarrier, both loaded and unloaded. In an experimental asthma model (Balb/c mice) of ovalbumin sensitization and challenge, the nanocarrier loaded and unloaded with formoterol was tested in a preventive strategy and compared to treatment with the drug in a normal formulation. The airway hyperresponsiveness (AHR) and pulmonary inflammation in the bronchoalveolar lavage (BAL), both cellular and biochemical, were assessed. The application of formoterol as a regular drug and the unloaded and formoterol-loaded NP in OVA-sensitized mice followed by a saline challenge was not different from the control group. Yet, both the NP formulation and the normal drug application led to a more deteriorated lung function and increased lung inflammation in the OVA-sensitized and -challenged mice, showing that the use of the p(HEMA) nanocarrier loaded with formoterol needs more extensive testing before it can be applied in clinical settings.

Oligosaccharides from regular milk and lactose-free milk were analyzed by Electrospray Ionization interface coupled with Ion Trap Mass Spectrometry (IT-MS). The negative mode mass spectrometry of sugar compositions was obtained either by direct infusion and mass spectrometry with Liquid Chromatography (LC). Hexose (Hex) and the other oligomeric sugar components were observed in both regular and lactose-free milk. While lactose derivatives (deprotonated lactose dimer, chloride adducts, chloride dimer) in regular milk have seen to be dominated, monosaccharide derivatives (Hex-H2O, Hex, Hex-Cl) in the lactose-free milk were observed as abundant which was lytic product of lactose. Phosphate/sulfate ester substitution on lactose and sialyllactose in both regular and lactose-free milk samples were observed with similar intensity thus it has been understood that these important milk components are not digested during lactose removing process.

Glycans are expressed as conjugates of glycoproteins, glycolipids, and proteoglycans. The huge diversity of glycans on glycoconjugates contributes to many biological processes, from glycan-based molecular recognition to developmental events, such as regeneration in the nervous system. Echinoderms, which have a close phylogenetic relationship with chordates, are an important group of marine invertebrates for body regeneration. Although many major roles of glycans on glycoconjugates are known, their role in the glycosylation profile of the nervous system in sea urchins is poorly understood. In this study, we aimed to determine the terminal glycan profile by lectin blotting and to quantify sialic acids by the capillary liquid chromatography electrospray ionization tandem mass spectrometry system in the nervous tissue of the sea urchin Paracentrotus lividus. We determined the N-acetyl-D-glucosamine, mannose, and sialic acids (mainly α2,3 linked) by lectin blotting and five types of sialic acids (N-glycolylneuraminic acid, N-acetylneuraminic acid, 9-O-acetyl-N-alycolylneuraminic acid, 5-N-acetyl-9-O-acetyl-N-acetylneuraminic acid, and di-O-acetylated-N-alycolylneuraminic acid) by capillary liquid chromatography electrospray ionization tandem mass spectrometry. This potential first description of the terminal glycan profile in the nervous system of the sea urchin is expected to help us understand its role in nervous system development and regeneration.

Para-toluic acid, a major pollutant in industrial wastewater, is hazardous to human health. It has been demonstrated that Gram-negative bacteria are among the most effective degraders of para-toluic acid. In this study, the ability of Comamonas testosteroni strain 3a2, isolated from a petrochemical industry wastewater, to degrade para-toluic acid was investigated. The effect of different carbon (glucose and ethylene glycol) and nitrogen sources (urea, yeast extract, peptone, NaNO₃, NH₄NO₃) on the biodegradation of para-toluic acid by the isolate 3a2 was evaluated. Furthermore, ring hydroxylating dioxygenase genes were amplified by PCR and their expression was evaluated during the biodegradation of para-toluic acid. The results indicated that strain 3a2 was able to degrade up to 1000 mg/L of para-toluic acid after 14 h. The highest degradation yield was recorded in the presence of yeast extract as nitrogen source. However, the formation of terephthalic acid and phthalic acid was noted during para-toluic acid degradation by the isolate 3a2. Toluate 1,2-dioxygenase, terephthalate 1,2 dioxygenase, and phthalate 4,5 dioxygenase genes were detected in the genomic DNA of 3a2. The induction of ring hydroxylating dioxygenase genes was proportional to the concentration of each hydrocarbon. This study showed that the isolate 3a2 can produce terephthalate and phthalate during the para-toluic acid biodegradation, which were also degraded after 24 h.

Biodegradation is a cost-effective process commonly used to eliminate many xenobiotic hydrocarbons such as diesel oils. However, their hydrophobic character reduces the biodegradation efficiency. In order to overcome this hurdle, kurstakins isolated from Bacillus thuringiensis strain 7SA were used as emulsifying agents. The influence of kurstakin molecules on diesel oil degradation by Acinetobacter haemolyticus strain 2SA was evaluated in the presence and absence of the aforementioned lipopeptide. The degradation rates and gene expressions of alkane hydroxylases were evaluated at days 4, 10, 14 and 21. Results showed that kurstakin molecules increased the hydrophobicity of 2SA. Moreover, diesel oil degradation activities were higher in the presence of kurstakin with 29%, 35%, 29% and 23% improvement at 4th, 10th, 14th and 21st day respectively. Statistical analysis indicated that the difference between the degradation rates in the presence and absence of kurstakin was significant with p = 0.03. The detection of three different hydroxylase genes namely alkB, almA and cyp153 in 2SA genome, might have allowed more efficient degradability of alkanes. According to the real-time PCR results, cyp153 was the most induced gene during diesel oil degradation in the presence and absence of kurstakin. Yet, the three genes demonstrated higher levels of expression in the presence of kurstakin when compared to its absence. This study showed that kurstakins enhance the diesel oil biodegradation rate by increasing the hydrophobicity of 2SA. In addition to their anti-fungal activities, kurstakins can be used as biosurfactant to increase biodegradation of diesel oil.

Nicotine, is an alkaloid compound consisting of pyridine and pyrolidine ring. Its closed formula is C10H4N2. During smoking peak plasma concentration changes from 25 to 50 ng/mL. Its half-life is 1–2 h. Nicotine is metabolized primarily in the liver and excreted by the kidneys. The plasma concentration of the nicotine metabolite cotinine is 10 times more than nicotine and its half-life is longer around 15 to 20 h. Cotinine can be found in both amniotic fluid and umbilical cord blood given that it passes across the placental barrier. Adverse effects of nicotine and its metabolites on the fetus are suggested but have not been proven by scientific explanations till now. Sialic acid (Sia) is a modified nine-carbon sugar. They are located on the last end of the glycan chains located in the glycoconjugate structures. They organize a wide range of relationships between cells and their environment such as cellular recognition, adhesion, transmission, differentiation and aging. The aim of this study is to determine the possible changes in the sialic acid levels and types in the plasma after different levels of nicotine applied to Swiss Albino rats in order to assess the effect of long-term per oral nicotine administration.