Utjecaj prijenosa gena na evoluciju bakterija mliječne kiseline

In the case of preparing various dairy products, the exploitation of lactic acid bacteria has been essential in the course of past millennia in all known nations. Numerous comparative analyses of gene and genome sequences reveal that the exchange of genetic material within and between bacterial species is far more general and frequent than has previously been thought. Consequently, the horizontal gene transfer between distant species or within the same species is an important factor in the Lactobacillales evolution. Knowledge about the exchange of lactobacillus genetic information through horizontal gene transfer, mobile genetic elements, and its evolution is very important due to characterizations and stability maintenance of autochthonous as well as industrial lactic acid bacteria strains in dairy products that benefit human health.Tijekom tisućljeća u cijelom su svijetu bakterije mliječne kiseline bile prijeko potrebne za pripremu raznovrsnih mliječnih proizvoda. Brojne usporedne analize sekvencija gena i genoma prokariota pokazuju da su izmjene genetičkoga materijala unutar i između bakterijskih vrsta mnogo uobičajenije i češće nego se prije mislilo. Stoga je horizontalni prijenos gena između udaljenih vrsta i unutar iste vrste osobito važan za evoluciju bakterija reda Lactobacillales. Radi dobrobiti za ljudsko zdravlje, izmjena genetičkih informacija tijekom horizontalnog prijenosa gena, pokretni genetički elementi i evolucija laktobacila vrlo su značajni zbog karakterizacije i očuvanja stabilnosti autohtonih, a i industrijskih sojeva bakterija mliječne kiseline u mliječnim proizvodima

The Role of Mismatch Repair in Bacterial Evolution

Experimental (directed) evolution is a study of evolution under defined and reproducible conditions, particularly on model laboratory populations of bacteria. Recently, remarkable success of directed evolution has been reported, ranging from industrial enzymes, with substantially improved activities and thermostabilities, to vaccines and pharmaceuticals as well as a generation of novel microorganisms with desired properties. It has become clear that the major process influencing evolution is DNA Mismatch Repair (MMR). The MMR system controls genome stability of the species and is highly conserved from bacteria to humans. It maintains the integrity of DNA by repairing errors made during the replication process and by preventing genetic recombination between diverged DNAs. Inactivation of MMR results in the generation of hereditary mutators with highly increased mutation rates as well as in abolishment of genetic barriers between species. Most of the mutations are deleterious, but some of them are beneficial and enable mutators to survive environmental stress. In the stable environment mutators lose their advantage because of accumulating deleterious mutations. Strains with beneficial mutations could survive by reacquiring MMR wild type alleles in horizontal gene transfer through hyperrecombination phenotype of MMR mutators. During evolutionary history, MMR functions have been repeatedly lost and reacquired by horizontal gene transfer, which gives rise to the mosaic gene structure of MMR genes. This mosaicism is a hallmark of the evolutionary process

The Effects of Olive and Pumpkin Seed Oil on Serum Lipid Concentrations

Low-fat diets increase serum triacilglycerol and decrease HDL-cholesterol concentrations, thereby potentially adversely affecting cardiovascular disease (CVD) risk. The present study compared the CVD risk profi le of a high-MUFA diets (olive oil) and high-PUFA diets (pumpkin seed oil). The most signifi cant difference between the two groups was that the atherogenic index in groups given olive oil was significantly lower (for approximately 60 %) than atherogenic index recorded in control group, while in the group receiving pumpkin seed oil this reduction was approximately 40 %. Collectively, these fi ndings point to the fact that both a high MUFA and PUFA diet may be preferable to a low-fat diet because of more favorable effects on the CVD risk profile

What is Nutrigenomics?

Uspjehom projekta sekvencioniranja ljudskog genoma, povećalo se razumijevanje uzroka, a time i prevencije različitih bolesti u ljudi. Spoznalo se da mijenjajući prehrambene navike možemo spriječiti pojavu nekih bolesti. Tako se na području istraživanja prehrane razvija nova disciplina, nutrigenomika. Taj novi smjer molekularne prehrane omogućuje upoznavanje pozadine interakcije hrane koju konzumiramo i našeg genetičkog profi la, a time nam daje i mogućnost razvoja novih načina liječenja i prevencije bolesti. U ovom radu opisani su osnovni ciljevi i metode nutrigenomike te njena praktična primjena u razvoju koncepta individualne prehraneThe success of sequencing the human genome has led to the increasing understanding of causes and thus the prevention of various human illnesses. It is understood that by adjusting ones dieting habits one can prevent disease appearance. Such knowledge has made way for a new discipline in the fi eld of nutrition research, nutrigenomics. This novel direction of molecular nutrition provides insight into the interaction of the food we consume and our genetic profi le, and therefore grants the possibility to develop new methods of treatment and disease prevention. This article encloses the description of the primary objective and the methods of nutrigenomics as well as its practical implementation in the development of an individual diet concept

Evolucija bakterija tijekom stacionarne faze rasta

Metagenomics and advances in molecular biology methods have enhanced knowledge of microbial evolution, metabolism, functions, their interactions with other organisms and their environment. The ability to persist and adapt to changes in their environment is a common lifestyle of 1 % of the known culturable bacteria. Studies in the variety of species have identified an incredible diversity of bacterial lifespan. The holy grail of molecular biology is to understand the integrated genetic and metabolic patterns of prokaryotic organisms like the enteric bacterium Escherichia coli. The usual description of E. coli life cycle comprises four phases: lag, logarithmic, stationary, and death phase, omitting their persistence and evolution during prolonged stationary phase. During prolonged stationary/starvation period, in batch bacterial culture, selected mutants with increased fitness express growth advantage in stationary phase (GASP), which enables them to grow and displace the parent cells as the majority population. The analyses of growth competition of Gram-negative and/or Gram-positive mixed bacterial cultures showed that GASP phenomenon can result in four GASP phenotypes: strong, moderate, weak or abortive. Bacterial stress responses to starvation include functions that can increase genetic variability and produce transient mutator state, which is important for adaptive evolution.Metagenomika i suvremene metode molekularne biologije omogućili su razumijevanje evolucije, metabolizma i funkcije mikroorganizama te njihovih interakcija s drugim organizmima u okolišu. Otpornost i prilagodba na promjene u okolišu uobičajeni su za 1 % poznatih bakterija što se mogu uzgajati u laboratoriju. Istraživanjem različitih bakterijskih vrsta uočena je njihova velika raznolikost. Escherichia coli je „sveti gral“ molekularne biologije u razumijevanju genetike i metaboličkih modela. Životni se ciklus E. coli sastoji od četiri faze: lag, logaritamske, stacionarne i faze odumiranja, zanemarujući bakterijsku postojanost i evoluciju tijekom produljene stacionarne faze. U šaržnoj bakterijskoj kulturi, tijekom produljene stacionarne faze ili vremena izgladnjivanja, preživjele stanice mutanata brže rastu (engl. growth advantage in stationary phase - GASP), pa prerastaju i zamjenjuju većinu roditeljskih stanica. Analiza kompetitivnoga rasta Gram-pozitivnih i/ili Gram-negativnih bakterija, tijekom produljene stacionarne faze u mješovitim kulturama, pokazala je postojanje četiriju GASP fenotipova: jaki, umjereni, slabi i nerazvijeni. Bakterijski odgovor na izgladnjivanje obuhvaća stanične funkcije koje mogu povećati genetičku raznolikost i stvarati mutator stanice bitne za adaptivnu evoluciju bakterija

Pretilost – međudjelovanje genoma i okoline

Obesity has become one of the major threats for public health in industrialised world among adults, but also among adolescents and children. It is influenced by the interaction of genes, nutrition, environment, and lifestyle. Environmental and lifestyle risk factors include foetal and lifelong environment, nutrient quality, chemical and microbial exposure, and psychical stress, all of which are important contributing influences. Removing or limiting chemical and pharmaceutical obesogens from human environment could make a difference in the growing epidemic of obesity. Additionally, nutrigenomics describes how modifications in individual diets can improve health and prevent chronic diseases, as well as obesity, by understanding the effects of a genetic profile in the interaction between food and increase in body weight. Furthermore, individual genetic variations in genome represent an individual′s predisposition for obesity. Therefore, the use of individual genetic information, avoiding obesogens, and a healthy lifestyle could help to improve the management of obesity and maintain a healthy weight.U industrijaliziranom svijetu među odraslim osobama, adolescentima i djecom pretilost je postala jedna od glavnih prijetnja za javno zdravlje ljudi. Njezina je pojavnost pod utjecajem međudjelovanja gena, prehrane, okoliša i načina života. Važni čimbenici rizika vezani su uz okolinu i način života, uključujući čimbenike prisutne već u okruženju fetusa te one prisutne tijekom cijeloga života kao što su kvaliteta prehrane, izloženost kemikalijama, mikroorganizmima i psihičkom stresu. Uklanjanje ili ograničavanje kemijskih tvari i lijekova koji uzrokuju pretilost iz ljudske okoline moglo bi utjecati na opadanje epidemije pretilosti. Dodatno, nutrigenomika opisuje kako se promjenama u prehrani pojedinca može poboljšati zdravstveno stanje i spriječiti razvoj kroničnih bolesti, uključujući i pretilost, a pritom je potrebno poznavati utjecaj genskog profila na međudjelovanje hrane i porasta tjelesne mase. Nadalje, genske varijacije u genomu pojedinih osoba stvaraju i njihovu predispoziciju za razvoj pretilosti. Stoga se zahvaljujući informacijama o genskom profilu pojedinca, izbjegavanjem tvari koje uzrokuju pretilost i zdravim načinom života može poboljšati kontrola pretilosti i održavati optimalna tjelesna masa

Characterization of a S-adenosyl-l-methionine (SAM)-accumulating strain of Scheffersomyces stipitis

S-adenosyl-l-methionine (SAM) is an important molecule in the cellular metabolism of mammals. In this study, we examined several of the physiological characteristics of a SAM-accumulating strain of the yeast Scheffersomyces stipitis (M12), including SAM production, ergosterol content, and ethanol tolerance. S. stipitis M12 accumulated up to 52.48 mg SAM/g dry cell weight. Proteome analyses showed that the disruption of C-24 methylation in ergosterol biosynthesis, a step mediated by C-24 sterol methyltransferase (Erg6p), results in SAM accumulation by S. stipitis M12 compared to the wild-type strain. A comparative proteome-wide analysis identified 25 proteins that were differentially expressed by S. stipitis M12. These proteins are involved in ribosome biogenesis, translation, the stress response, ubiquitin-dependent catabolic processes, the cell cycle, ethanol tolerance, posttranslational modification, peroxisomal membrane stability, epigenetic regulation, the actin cytoskeleton and cell morphology, iron and copper homeostasis, cell signaling, and energy metabolism. [Int Microbiol 2015; 18(2):117-125]Keywords: Scheffersomyces stipitis · S-adenosyl- l-methionine (SAM) · SAM accumulating yeast · C-24 sterol methyltransferase (Erg6p

Polimorfizmi gena FTO na raskrižju metaboličkih puteva pretilosti i epigenetskih utjecaja

In this review, we summarize the current state of knowledge on the fat mass and obesity-associated (FTO) gene and its role in obesity. The FTO-encoded protein is involved in multiple molecular pathways contributing to obesity as well as other metabolic complexities. This review emphasizes the epigenetic influence on the FTO gene as a new approach in the treatment and management of obesity. Several known substances have a positive effect on reducing FTO expression. Depending on which variant of the single nucleotide polymorphism (SNP) is present, the profile and level of gene expression changes. Implementation of environmental change measures could lead to reduced phenotypic manifestation of FTO expression. Treating obesity through FTO gene regulation will have to include various complex signal pathways in which FTO takes part. Identification of FTO gene polymorphisms may be useful for the development of individual obesity management strategies, including the recommendation of taking certain foods and supplements.U ovom preglednom radu sažete su trenutne spoznaje o genu FTO (engl. fat mass and obesity-associated gene) i njegovoj ulozi u razvoju pretilosti. Protein kodiran genom FTO je uključen u razne molekularne puteve koji pridonose pretilosti i drugim metaboličkim poremećajima. Ovaj rad naglašava epigenetski utjecaj gena FTO kao novog pristupa u liječenju pretilosti. Nekoliko poznatih tvari ima pozitivan utjecaj na redukciju ekspresije gena FTO. Ovisno o tome koja je varijanta jednostrukog nukleotidnog polimorfizma (engl. single nucleotide polymorphism, SNP) prisutna, mijenja se profil i razina ekspresije gena. Promjenom uvjeta okoliša može se smanjiti fenotipsko ispoljavanje ekspresije gena FTO. U liječenje pretilosti regulacijom gena FTO treba uključiti različite složene signalne puteve u kojima sudjeluje i sam gen. Identifikacija polimorfizama gena FTO može biti korisna za razvoj individualnih strategija upravljanja pretilošću, uključujući donošenje preporuka za konzumiranje određenih namirnica i suplemenata

Evolucija bakterija tijekom stacionarne faze rasta

Metagenomics and advances in molecular biology methods have enhanced knowledge of microbial evolution, metabolism, functions, their interactions with other organisms and their environment. The ability to persist and adapt to changes in their environment is a common lifestyle of 1 % of the known culturable bacteria. Studies in the variety of species have identified an incredible diversity of bacterial lifespan. The holy grail of molecular biology is to understand the integrated genetic and metabolic patterns of prokaryotic organisms like the enteric bacterium Escherichia coli. The usual description of E. coli life cycle comprises four phases: lag, logarithmic, stationary, and death phase, omitting their persistence and evolution during prolonged stationary phase. During prolonged stationary/starvation period, in batch bacterial culture, selected mutants with increased fitness express growth advantage in stationary phase (GASP), which enables them to grow and displace the parent cells as the majority population. The analyses of growth competition of Gram-negative and/or Gram-positive mixed bacterial cultures showed that GASP phenomenon can result in four GASP phenotypes: strong, moderate, weak or abortive. Bacterial stress responses to starvation include functions that can increase genetic variability and produce transient mutator state, which is important for adaptive evolution.Metagenomika i suvremene metode molekularne biologije omogućili su razumijevanje evolucije, metabolizma i funkcije mikroorganizama te njihovih interakcija s drugim organizmima u okolišu. Otpornost i prilagodba na promjene u okolišu uobičajeni su za 1 % poznatih bakterija što se mogu uzgajati u laboratoriju. Istraživanjem različitih bakterijskih vrsta uočena je njihova velika raznolikost. Escherichia coli je „sveti gral“ molekularne biologije u razumijevanju genetike i metaboličkih modela. Životni se ciklus E. coli sastoji od četiri faze: lag, logaritamske, stacionarne i faze odumiranja, zanemarujući bakterijsku postojanost i evoluciju tijekom produljene stacionarne faze. U šaržnoj bakterijskoj kulturi, tijekom produljene stacionarne faze ili vremena izgladnjivanja, preživjele stanice mutanata brže rastu (engl. growth advantage in stationary phase - GASP), pa prerastaju i zamjenjuju većinu roditeljskih stanica. Analiza kompetitivnoga rasta Gram-pozitivnih i/ili Gram-negativnih bakterija, tijekom produljene stacionarne faze u mješovitim kulturama, pokazala je postojanje četiriju GASP fenotipova: jaki, umjereni, slabi i nerazvijeni. Bakterijski odgovor na izgladnjivanje obuhvaća stanične funkcije koje mogu povećati genetičku raznolikost i stvarati mutator stanice bitne za adaptivnu evoluciju bakterija

Analytical methods in food forensics

U Europskoj uniji propisane kontrole za sigurnost hrane prema zakonskim aktima određuju provjeru hrane prije stavljanja na tržište. Tijekom proteklog desetljeća provjera kakvoće, autohtonosti i sljedivosti hrane poboljšana je ubrzanim razvojem osjetljivih, robusnih, učinkovitih i cjenovno prihvatljivih analitičkih metoda. Ovaj rad opisuje najučinkovitije analitičke metode za forenziku hrane i prikazuje njihovu primjenu u određivanju: (1) kvalitativnih i kvantitativnih sastojaka hrane, (2) sigurnosti hrane obzirom na patogene mikroorganizme, nutritivne alergene, ostatke pesticida i toksina, (3) sljedivosti sukladno zemljopisnom i botaničkom podrijetlu te utjecaju tehnološke obrade i skladištenja. Obzirom na način ispitivanja, opisane analitičke metode podijeljene su u četiri skupine: biokemijske, molekularno-genetske, spektroskopske i spektrometrijske te separacijske metode.The European Union food safety legislation prescribes controls in order to implement the testing of food before putting it on the market. Over the past decade checking quality, originality and the traceability of food has improved the rapid development of sensitive, robust, efficient and affordable analytical methods. This paper describes the most effective analytical methods for forensic food and shows their use in determining: (i) qualitative and quantitative food ingredients, (ii) food safety due to pathogens, allergens, nutritional, residues of pesticides and toxins, (iii) traceability according to geographical and botanical origin and the impact of technological processing and storage. Given the way tests are described analytical methods are divided into four groups as following: biochemical, molecular-genetic, spectroscopic and spectrometric, and separation method