Probiotic characteristics of strain Lactobacillus brevis SF15b expressing S-proteins

Probiotici su živi mikroorganizmi koji, kada su prisutni u odgovarajućem broju, poboljšavaju zdravlje domaćina. Bakterije mliječne kiseline, među kojima se posebno ističu bakterije iz roda Lactobacillus, su najbolji modeli za probiotičku upotrebu te karakterizaciju pozitivnih učinaka. Cilj ovog rada bio je ispitati probiotička svojstva soja Lactobacillus brevis SF15B koji eksprimira S-proteine. Pritom se kao pozitivna kontrola koristio soj L. helveticus M92 koji eksprimira S-proteine, dok je negativna kontrola bio soj L. plantarum D13 koji navedene proteine ne eksprimira. Osim S-proteina, na površini stanica ispitivanog soja nalaze se i SLAP (Eng. Surface-Layer Associated Proteins). Uloga S-proteina u probiotičkom djelovanju soja SF15B ispitana je iz aspekta adhezije na mucin, prilikom čega je dokazano da prisutnost sloja S-proteina pridonosi boljim adhezijskim svojstvima. Osim toga, soj L. brevis SF15B ima sposobnost preživljavanja u pojedinim nepovoljnim uvjetima koji mogu vladati u ljudskom gastrointestinalnom traktu te pokazuje značajnu proteolitičku aktivnost.Probiotics are live microorganisms which, when administered in adequate amount, confer a health benefit on the host. Lactic acid bacteria, especially bacteria of the genus Lactobacillus, are of first choice microorganisms for probiotic application and characterization of their effect on human health. The aim of this study was to examine probiotic properties of the strain Lactobacillus brevis SF15B which expresses S-layer proteins. Strain L. helveticus M92, which also contains layer of S-proteins on the surface of the bacterial cells, was used as positive control, while strain L. plantarum D13, which doesn`t express mentioned proteins, was used as negative control. Besides S-layer proteins, on the cell surface of strain SF15B there are also SLAPs (Eng. Surface-Layer Associated Proteins). The role of S-layer proteins in probiotic activity of strain SF15B was examined from the aspect of adhesion to mucin, during which it was proven that the presence of S-layer proteins contributes to better adhesion properties. In addition, strain L. brevis SF15B has the ability to survive in the various rigorous conditions which are present in the human gastrointestinal tract and exhibits significant proteolytic activity

NEW DINOSAUR TRACKSITE IN THE LATE JURASSIC OF KIRMENJAK QUARRY (ISTRIA)

A new dinosaur tracksite was found in the Kirmenjak quarry in Istria. It is located about one kilometre from an already existing tracksite. The footprints are placed on a slightly inclined bedding plane at the base of the succession represented by heavily stylolitised limestones of the Kirmenjak informal lithostratigraphic unit. The age of the limestones is late Tithonian. Fifteen footprints of circular shape with no clear digit or claw impressions were found at the site and are interpreted to have been formed on a tidal flat during a sea-level fall. All of the footprints belong to sauropod dinosaurs. Pes prints are circular to elliptical in shape, whereas manus prints are more elliptical and of smaller size. The average length of the pes prints is 55 cm, which would correspond to a sauropod of approximately 16 meters in length. The trackway is of narrow-gauge type, where the internal trackway width often has a negative value. The length of the strides indicates slow movement of the individual with a speed of less than 2 km/h. Based on stratigraphic position and footprint morphology, the new and the pre-existing tracksites represent the same trackbearing layer

Influence of charge ratio of liposome/DNA complexes on their size after extrusion and transfection efficiency

Marija Brgles, Maja Šantak, Beata Halassy, Dubravko Forcic, Jelka TomašicInstitute of Immunology, Research and Development Department, Zagreb, CroatiaBackground: Physicochemical characteristics of liposome/DNA complexes influence transfection efficiency and affect each other in a very intricate way. The result of this is discrepancies in conclusions drawn about the individual influence of each one.Methods: Aiming to elucidate the influence of liposome/DNA charge ratio and size on transfection efficiency and on each other, we used liposome/DNA complexes with charge ratio (+/-) in the range of 1–50 and extruded through membranes of 400, 200, and 100 nm. Plasmid DNA encoding green fluorescent protein was used to measure transfection efficiency by flow cytometry. Sizes of liposome/DNA complexes were measured by dynamic light scattering.Results: Liposome size was reduced after extrusion but this was mainly driven by the charge ratio and not by the size of the membrane pores. Reduction of complex size at each charge ratio positively correlated with transfection efficiency. When the size of the complexes was approximately constant, increasing the charge ratio was found to promote transfection efficiency. Cationic lipid N-(1-(2,3-dioleoyloxy)propyl)N,N,N trimethylammonium chloride was used for modulation of positive charge and a cytotoxicity test showed that increasing its amount increases cytotoxicity.Conclusion: It can be concluded that charge ratio dictates the size of the complex whereas overall size reduction and higher charge ratios promote transfection efficiency in vitro.Keywords: transfection efficiency, liposome charge, liposome siz

Uporaba piezoelektričnog svojstva u poboljšanju kvalitete instrumenata i sigurnosti bolesnika u laparoskopskoj kirurgiji

The piezoelectric properties of some natural crystals and polymers can also be used in surgery. For this purpose, a prototype of an endoscopic instrument was constructed with piezoelectric material attached to its working end with the aim of recognizing pulsating blood vessels during laparoscopic surgery. To test the properties of the new instrument in laboratory conditions, simulated blood circulation was used with the possibility of changing pressure and frequency. The instrument was tested in the pressure range of 40-180 mm Hg at constant frequency of 72/min and frequency range of 36-130 beats per minute at constant pressure of 120 mm Hg. Test results showed that the instrument with certainty recognized a pulsating “blood vessel” in the expected pressure ranges and at different blood pump frequencies. Given the piezoelectric material’s very small dimensions and flexible form, it can be installed at the working end of most standard laparoscopic instruments and thus significantly increase certainty in the recognition of arteries during surgery, which would reduce the possibility of their injury or accidental ligation.Piezoelektrična svojstva nekih prirodnih kristala i nekih polimera moguće je koristiti i u kirurgiji. U tu svrhu konstruiran je prototip endoskopskog instrumenta na čijem je radnom dijelu ugrađen piezoelektrični materijal s ciljem prepoznavanja pulzirajućih krvnih žila tijekom laparoskopskih operacija. Za ispitivanje svojstava novoga instrumenta u laboratorijskim uvjetima korišten je simulirani krvotok s mogućnošću mijenjanja tlaka i frekvencije. Rad instrumenta je ispitivan u rasponu tlakova 40-180 mm Hg uz konstantnu frekvenciju 72/min, te u rasponu frekvencija 36-130 otkucaja u minuti uz konstantan tlak 120 mm Hg. Rezultati ispitivanja pokazuju da instrument sa sigurnošću prepoznaje pulzirajuću „krvnu žilu“ u očekivanom rasponu tlakova i pri različitim frekvencijama rada krvne pumpe. S obzirom na to da se radi o vrlo malim dimenzijama i prilagodljivim oblicima piezoelektričkog materijala, moguće ga je postaviti na radni dio većine standardnih laparoskopskih instrumenata i time značajno povećati sigurnost prepoznavanja arterija tijekom operacijskog zahvata, što bi smanjilo mogućnost njihove ozljede ili slučajnog podvezivanja

Common position of indels that cause deviations from canonical genome organization in different measles virus strains

BACKGROUND: The canonical genome organization of measles virus (MV) is characterized by total size of 15 894 nucleotides (nts) and defined length of every genomic region, both coding and non-coding. Only rarely have reports of strains possessing non-canonical genomic properties (possessing indels, with or without the change of total genome length) been published. The observed mutations are mutually compensatory in a sense that the total genome length remains polyhexameric. Although programmed and highly precise pseudo-templated nucleotide additions during transcription are inherent to polymerases of all viruses belonging to family Paramyxoviridae, a similar mechanism that would serve to non-randomly correct genome length, if an indel has occurred during replication, has so far not been described in the context of a complete virus genome. ----- METHODS: We compiled all complete MV genomic sequences (64 in total) available in open access sequence databases. Multiple sequence comparisons and phylogenetic analyses were performed with the aim of exploring whether non-recombinant and non-evolutionary linked measles strains that show deviations from canonical genome organization possess a common genetic characteristic. ----- RESULTS: In 11 MV sequences we detected deviations from canonical genome organization due to short indels located within homopolymeric stretches or next to them. In nine out of 11 identified non-canonical MV sequences, a common feature was observed: one mutation, either an insertion or a deletion, was located in a 28 nts long region in F gene 5' untranslated region (positions 5051-5078 in genomic cDNA of canonical strains). This segment is composed of five tandemly linked homopolymeric stretches, its consensus sequence is G6-7C7-8A6-7G1-3C5-6. Although none of the mononucleotide repeats within this segment has fixed length, the total number of nts in canonical strains is always 28. These nine non-canonical strains, as well as the tenth (not mutated in 5051-5078 segment), can be grouped in three clusters, based on their passage histories/epidemiological data/genetic similarities. There are no indications that the 3 clusters are evolutionary linked, other than the fact that they all belong to clade D. ----- CONCLUSIONS: A common narrow genomic region was found to be mutated in different, non-related, wild type strains suggesting that this region might have a function in non-random genome length corrections occurring during MV replication