Aflatoxin B1 sensitive isolates of Lactobacillus casei and Lb. lactis

Iz sireva gauda, trapist, podravac i a la belpaese izdvajane su štapićaste bakterije mliječne kiseline. Identifikacijom 25 izolata utvrđeno je da 3 pripadaju vrsti Lactobacillus lactis, a 22 izolata vrsti Lactobacillus casei var. casei. Aflatoksin B1 djeluje inhibitorno na čvrstoj podlozi na sve ispitane sojeve, dok u lakmus mlijeku svi sojevi proizvode kiselinu i gruš, brže nego u kontrolnom mlijeku bez aflatoksina. Pored toga, svi sojevi Lb. casei i jedan soj Lb. lactis u lakmus mlijeku sa aflatoksinom izdvajaju sirutku i plin, a dva soja Lb. lactis ne izdvajaju. Prema tome, veliki broj izolata homofermentativnih bakterija mliječne kiseline u prisustvu aflatoksina B1 postaju heterofermentativni.The lactic acid bacteria were isolated from cheeses Gauda, Trapist, Podravce na a la Belpaese. There were determinated 25 isolates. Among them 22 belong to species of Lactobacillus casei var. and 3 to Lb. lactis. The aflatoxin B1 inhibition of growth all isolates of lactic acid bacteria on the agar medium. On the other hand, all strains formed more acid and faster milk curdling in the aflatoxin B1 presence, than in control milk. In the same time on the surface of the curd occured the milk serum and gas was detected, except in the case with two strains of Lb. lactis. The data suggests that isolated homofermentative lactic acid bacteria become heterofermentative due to the influence of aflatoxin

Organic-inorganic nanocomposites for biomedical applications

Polyurethane (PU) and PU nanocomposites with good biocompatibility and mechanical properties can be used as the biomedical matrix and tissue engineering biomaterials. Magnetic nanoparticles, especially ferrite nanoparticles have attracted much interest due to their specific physicochemical properties in various areas including magnetic recording, biosensing, catalyst, drug delivery systems, magnetic resonance imaging (MRI) and cancer therapy. Despite all these advantages, the nanoparticle agglomeration reduces the efficiency of the nanoparticles, so the nanoparticle incorporation into an appropriate polymeric matrix to prepare organic-inorganic nanocomposites is a right direction in the current scenario of biomedical nanotechnology. In this study, organic-inorganic PU nanocomposites based on zinc and copper ferrites and with the same composition of PU were prepared. The properties of PU nanocomposites were evaluated by nanoindentation, water contact angle and water absorption measurements. The presence of the nanoferrite nanoparticles affects properties of PU nanocomposites such as bulk morphology, mechanical, and biological properties. The biocompatibility of PU nanocomposites was investigated by MTT assay and cell attachment using endothelial cells. According to the results, the prepared PU nanocomposites with noncytotoxic chemistry could be a potential choice for vascular implants development.RAD 2023 : 11th International Conference on Radiation Natural Sciences, Medicine, Engineering, Technology and Ecology (RAD 2023) 19–23.06.2023; Herceg Novi, Montenegr

Expression, purification and immunological characterization of recombinant protein fragment from SARS-CoV-2

Serological testing is important method for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection. Nucleocapsid (N) protein is the most abundant virus derived protein and strong immunogen. We aimed to find its efficient, low-cost production, suitable for serological diagnosis. SARS-CoV-2 recombinant fragment of nucleocapsid protein (rfNP; 58–419 aa) was expressed in E. coli in soluble form, purified by immobilized metal ion affinity chromatography and strong cation exchange chromatography after which it was analyzed by Mass and CD spectrometry and characterized biochemically and immunologically. Purified rfNP has secondary structure of full-length recombinant N protein, with high percentage of disordered structure (34.2%) and of β-sheet (40.7%). rfNP was tested in immunoblot using sera of COVID-19 convalescent patients. ELISA was optimized with sera of RT-PCR confirmed positive symptomatic patients and healthy individuals. IgG detection sensitivity was 96% (47/50) and specificity 97% (67/68), while IgM detection was slightly lower (94% and 96.5%, respectively). Cost-effective approach for soluble recombinant N protein fragment production was developed, with reliable IgG and IgM antibodies detection of SARS-CoV-2 infection.Book of Abstract

The role of school climate and socio-demographic characteristics in explaining students achievements in Primary school Ilača-Banovci, Ilača

U radu je ispitana uloga školske klime i socijalno demografskih obilježja u objašnjenju postignuća učenika u Osnovnoj školi Ilača-Banovci. Zbog heterogenosti učenika s obzirom na različite čimbenike, u ovom je istraživanju naglasak stavljen na socijalno demografska obilježja učenika i njihovih obitelji, a to su dob i spol učenika, zaposlenost roditelja, obrazovanje i radni odnos roditelja, prihodi i struktura obitelji. U radu su postavljeni specifični istraživački problemi: ispitati razlike u školskom postignuću te percepciji školske klime učenika različitih socijalno demografskih obilježja, kao i povezanost između učeničke percepcije školske klime i školskog postignuća učenika. Za mjerenje školske klime korišten je Hrvatski upitnik školske klime za učenike (HUŠK-U, Velki i Antunović, 2014). U skladu s postavljenim ciljevima najprije su analizirane razlike u školskom postignuću učenika različitih socijalno demografskih obilježja (dob i spol učenika te zaposlenost roditelja, obrazovanje i radni odnos roditelja, prihodi i struktura obitelji) te zatim razlike u percepciji školske klime s obzirom na ista socijalno demografska obilježja. Nakon toga izračunata je povezanost između školskog postignuća i percepcije školske klime. Dobivena je statistički značajna razlika u općem školskom uspjehu uzevši u obzir razred kojeg učenici pohađaju. Pri tome učenici 5. i 6. razreda postižu nešto bolji školski uspjeh na kraju školske godine 2019./20. od učenika 7. i 8. razreda. Školski uspjeh učenika nije se statistički značajno razlikovao uzevši u obzir ostala socijalno demografska obilježja. Formiran je ukupan rezultat u upitniku te se može zaključiti da učenici školsku klimu percipiraju vrlo pozitivnom te da učenička percepcija klime nije povezana sa školskim postignućem.This paper examines the role of school climate and socio-demographic characteristics in explaining student achievement in the Ilača-Banovci Elementary School. Due to the heterogeneity of students with respect to various factors, this study focused on the sociodemographic characteristics of students and their families, namely students age and gender, parents’ employment, parents’ education, income and family structure. This paper presents specific research problems: to examine the differences in school achievement and perception of school climate in students' of different socio-demographic characteristics, as well as the relationship between students' perception of school climate and students' school achievement. To measure the school climate the Croatian School Climate Questionnaire for Students (HUŠKU, Velki and Antunović, 2014) was used. In accordance with the set goals, the differences in school achievement of students of different socio-demographic characteristics (age and gender of students and employment of parents, education and employment of parents, income and family structure) were analyzed first and then the differences in perception of school climate with regard to the same socio-demographic features. After that, the correlation between school achievement and perception of school climate was calculated. A statistically significant difference in overall school achievement was obtained with respect to the grade that students attend. At the same time, 5th and 6th grade students achieve slightly better school successes at the end of the 2019/20 school year in comparison to the 7th and 8th grade students. Students' school success did not statistically significantly differ with respect to the other socio-demographic characteristics. The overall result in the questionnaire was formed and it can be concluded that students perceive the school climate very positively and that students' perception of the climate is not related to school achievement

Isolation of Hemoglobin from Bovine Erythrocytes by Controlled Hemolysis in the Membrane Bioreactor

In this work, we describe an optimized procedure based on gradual hemolysis for the isolation of hemoglobin derived from bovine slaughterhouse erythrocytes in a membrane bioreactor. The membrane bioreactor system that provided high yields of hemoglobin (mainly oxyhemoglobin derivate) and its separation from the empty erythrocyte membranes (ghosts) was designed at a pilot scale. Ten different concentrations of hypotonic media were assessed from the aspect of the extent of hemolysis, hematocrit values of the erythrocyte suspensions, cell swelling, and membrane deformations induced by decreased salt concentration. Effective gradual osmotic hemolysis with an extent of hemolysis of 88% was performed using 35 mM Na-phosphate/NaCl buffer of pH 7.2-7.4. Under these conditions most of the cell membranes presented the appearance of the normal ghosts under phase contrast microscope. The hemoglobin purity of gt 80% was confirmed by SDS-PAGE. Kinetic studies showed that maximal concentration of hemoglobin was reached after 40 min, but the process cycle at which recovery of 83% was achieved lasted for 90 min. The dynamics of both steps, (1) transport through the membrane of erythrocytes during process of hemolysis and (2) transport through the reactor filters, were evaluated

Immunomodulatory effects of Trichinella spiralis-derived excretory-secretory antigens

Helminth-derived products, either released into the circulation during the course of the infection or isolated after in vitro cultivation of the parasite and applied by the injection, are able to suppress the host immune response to autoantigens and allergens, but mechanisms could differ. Prophylactic application of Trichinella spiralis excretory-secretory muscle larvae (ES L1) products ameliorates experimental autoimmune encephalomyelitis (EAE) with the same success as infection did. However, a shift to the Th2-type response in the periphery and in the central nervous system, accompanied by activation of regulatory mechanisms, had a striking, new feature of increased proportion of unconventional CD4(+)CD25(-)Foxp3(+) regulatory cells both in the periphery and in the central nervous system of animals treated with ES L1 before the induction of EAE

Characterization of polyurethane/ferrite nanocomposites

Polyurethane (PU) nanocomposite materials, offer very desirable advantages over pure PU materials,as the nanocomposites have enhanced thermal, surface, mechanical and biological properties. The main goal of this study was to develop a new kind of novel nanocomposites consisting of crosslinked PUs (based on poly(dimetylsiloxane) and hyperbranched polyester) and ferrite nanoparticles (based on copper and zinc) for possible application as coatings on biomedical devices and implants. A series of PU/ferrite nanocomposites was prepared by in situ polymerization in solution. Characterization of prepared nanocomposites nanocomposites was conducted by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Copper and zinc releases were investigated by microwave plasma atomic emission spectrometry (MP-AES). Characteristics of the prepared nanocomposites when in contact with a biological environment were examined through testing their biocompatibility, and adhesion of fibroblast cells. The presence of the nanoferrite nanoparticles influenced on surface and biological properties of PU nanocomposites. The prepared PU nanocomposites with noncytotoxic chemistry could be used as promising materials for vascular implants development.Obradović N, Mančić L, editors. Program and the Book of Abstracts: Serbian Ceramic Society Conference Advanced Ceramics and Application 11: New Frontiers in Multifunctional Material Science and Processing; 2023 Sep 18-20; Belgrade, Serbia. Belgrade: Serbian Ceramic Society; 2023. p. 65

Lignocellulosic waste material as substrate for Avicelase production by a new strain of Paenibacillus chitinolyticus CKS1

A novel strain of Paenibacillus chitinolyticus CKS1 was isolated from forest soil and identified as a potent cellulase producer. The strain was able to grow on various commercial substrates including microcrystalline cellulose (Avicel), carboxymethylcellulose (CMC), and cellobiose but also on lignocellulosic waste material such as medicinal herbs waste and sawdust. On all these substrates the strain produced cellulase composed of two subunits (similar to 70 and similar to 45 kDa) that was active on CMC, Avicel and filter paper. The maximal Avicelase activity (1.94 U/ml) was reached in a medium that contained 0.1% (w/v) of medicinal herbs waste, 3 g l(-1) of yeast extract and 5.0 g l(-1) of casein hydrolysate in 0.1 M phosphate buffer pH 7, after 48 h of incubation at 30 degrees C. The Avicelase performed optimally at 80 degrees C and at pH 4.8. Addition of K+ increased the Avicelase activity almost three fold and the enzyme retained 48.39% of the initial activity after 60 min. The product of Avicel and CMC hydrolysis was glucose with traces of other soluble sugars, indicating that the crude cellulase produced on waste material using the novel P. chitinolyticus strain CKS 1 could be used in eco-friendly processes of cellulose bioconversion, such as enzymatic saccharification of lignocellulosic materials in processes performed under acidophilic conditions and high temperatures

Knowledge, Attitudes and Practices of Parents and Pediatricians Regarding Antibiotic Use among Children: Differences in Relation to the Level of Education of the Parents in the Republic of Srpska Bosnia and Herzegovina

Antibiotics are often misused, especially for the treatment of upper respiratory tract infections (URTIs) in children, where their use is unnecessary and leads to antimicrobial resistance. This study sought to explore the knowledge, attitudes and practices (KAP) of parents and pediatricians on the use of antibiotics among children and whether the level of education of parents has an impact on their KAP. The research was carried out among 1459 parents of children under 6 years of age and among 18 pediatricians. Sixty percent of pediatricians (61.1%) were prescribed antibiotics daily in their practice. Most of the surveyed parents (98.4%) state that doctors are their main source of information when deciding on the use of antibiotics in the treatment of their children. Parents with a higher level of education use television less often as a source of information when making this decision compared to parents with a lower level of education (p = 0.039, i.e., p = 0.003). The majority of parents (80.7%) knew that Panklav (amoxicillin/clavulanic acid) is an antibiotic, while 52.5% identified Pancef (cefixime) as an antibiotic. Parents with a higher level of education correctly identified antibiotics significantly more often (p < 0.001). This study shows that in the Republic of Srpska, parents have adequate knowledge about antibiotics, especially those with a higher level of education, who show better KAP when it comes to antibiotic use