Molecular phylogeny of the hominoids

Početci istraživanja ljudskog filogenetskog stabla su se zasnivali na subjektivnoj metodi koja je koristila morfološka obilježja za njegovu rekonstrukciju. U 20. st. genetika i molekularna biologija uvode ljudski genom kao osnovu istraživanja evolucijskih odnosa. Osnovne metode postaju DNA hibridizacija i sekvencioniranje genoma. Zahvaljujući tim metodama za našu najbližu sestrinsku grupu stavljamo čimpanze. Pažnja se posvećuje i manjim DNA sekvencama poput mitohondrijske DNA ili Y kromosoma. To nam je omogućilo ne samo bolji uvid u našu evolucijsku granu rodoslovnog stabla, već i praćenje ekspanzije ljudskih populacija kroz povijest. Korijen naše civilizacije se nalazi u Africi te se preko Europe i Azije širi u ostatak svijeta. To je potkrijepljeno i teorijom „out of Africa“ koja sugerira razvoj i ekspanziju modernih ljudi iz Afrike u ostatak svijeta. Danas se najveće polemike vode oko “karike koja nedostaje” i njenih dosad pronađenih kandidata.The beginning of scientific research of human phylogenetic tree was based upon the subjective method which applied morphologic characteristics for its reconstruction. In 20. century genetic and molecular biology introduced human genome as the base for evolution relationship research. DNA hybridization and genome sequencing became basic methods. Owing to those methods we put chimpanzee as our nearest sister group. We also put our focus on smaller DNA sequences such as mitochondrial DNA or Y chromosome. That provided not only a better insight to our evolution branch of human family tree, but also to track expansions of human populations during history. The root of our civilization lies in Africa and spreads over Europe and Asia to the rest of the world. That point of view is also supported by „out of Africa“ theory which suggested that modern humans developed in Africa and then spread to the rest of the world. Today, the biggest controversy is the “missing link” and the candidates that represent it

Molecular phylogeny of the hominoids

Početci istraživanja ljudskog filogenetskog stabla su se zasnivali na subjektivnoj metodi koja je koristila morfološka obilježja za njegovu rekonstrukciju. U 20. st. genetika i molekularna biologija uvode ljudski genom kao osnovu istraživanja evolucijskih odnosa. Osnovne metode postaju DNA hibridizacija i sekvencioniranje genoma. Zahvaljujući tim metodama za našu najbližu sestrinsku grupu stavljamo čimpanze. Pažnja se posvećuje i manjim DNA sekvencama poput mitohondrijske DNA ili Y kromosoma. To nam je omogućilo ne samo bolji uvid u našu evolucijsku granu rodoslovnog stabla, već i praćenje ekspanzije ljudskih populacija kroz povijest. Korijen naše civilizacije se nalazi u Africi te se preko Europe i Azije širi u ostatak svijeta. To je potkrijepljeno i teorijom „out of Africa“ koja sugerira razvoj i ekspanziju modernih ljudi iz Afrike u ostatak svijeta. Danas se najveće polemike vode oko “karike koja nedostaje” i njenih dosad pronađenih kandidata.The beginning of scientific research of human phylogenetic tree was based upon the subjective method which applied morphologic characteristics for its reconstruction. In 20. century genetic and molecular biology introduced human genome as the base for evolution relationship research. DNA hybridization and genome sequencing became basic methods. Owing to those methods we put chimpanzee as our nearest sister group. We also put our focus on smaller DNA sequences such as mitochondrial DNA or Y chromosome. That provided not only a better insight to our evolution branch of human family tree, but also to track expansions of human populations during history. The root of our civilization lies in Africa and spreads over Europe and Asia to the rest of the world. That point of view is also supported by „out of Africa“ theory which suggested that modern humans developed in Africa and then spread to the rest of the world. Today, the biggest controversy is the “missing link” and the candidates that represent it

Molecular phylogeny of the hominoids

Početci istraživanja ljudskog filogenetskog stabla su se zasnivali na subjektivnoj metodi koja je koristila morfološka obilježja za njegovu rekonstrukciju. U 20. st. genetika i molekularna biologija uvode ljudski genom kao osnovu istraživanja evolucijskih odnosa. Osnovne metode postaju DNA hibridizacija i sekvencioniranje genoma. Zahvaljujući tim metodama za našu najbližu sestrinsku grupu stavljamo čimpanze. Pažnja se posvećuje i manjim DNA sekvencama poput mitohondrijske DNA ili Y kromosoma. To nam je omogućilo ne samo bolji uvid u našu evolucijsku granu rodoslovnog stabla, već i praćenje ekspanzije ljudskih populacija kroz povijest. Korijen naše civilizacije se nalazi u Africi te se preko Europe i Azije širi u ostatak svijeta. To je potkrijepljeno i teorijom „out of Africa“ koja sugerira razvoj i ekspanziju modernih ljudi iz Afrike u ostatak svijeta. Danas se najveće polemike vode oko “karike koja nedostaje” i njenih dosad pronađenih kandidata.The beginning of scientific research of human phylogenetic tree was based upon the subjective method which applied morphologic characteristics for its reconstruction. In 20. century genetic and molecular biology introduced human genome as the base for evolution relationship research. DNA hybridization and genome sequencing became basic methods. Owing to those methods we put chimpanzee as our nearest sister group. We also put our focus on smaller DNA sequences such as mitochondrial DNA or Y chromosome. That provided not only a better insight to our evolution branch of human family tree, but also to track expansions of human populations during history. The root of our civilization lies in Africa and spreads over Europe and Asia to the rest of the world. That point of view is also supported by „out of Africa“ theory which suggested that modern humans developed in Africa and then spread to the rest of the world. Today, the biggest controversy is the “missing link” and the candidates that represent it

Genetic changes of MLH1 and MSH2 genes could explain constant findings on microsatellite instability in intracranial meningioma

Postreplicative mismatch repair safeguards the stability of our genome. The defects in its functioning will give rise to microsatellite instability. In this study, 50 meningiomas were investigated for microsatellite instability. Two major mismatch repair genes, MLH1 and MSH2, were analyzed using microsatellite markers D1S1611 and BAT26 amplified by polymerase chain reaction and visualized by gel electrophoresis on high-resolution gels. Furthermore, genes DVL3 (D3S1262), AXIN1 (D16S3399), and CDH1 (D16S752) were also investigated for microsatellite instability. Our study revealed constant presence of microsatellite instability in meningioma patients when compared to their autologous blood DNA. Altogether 38% of meningiomas showed microsatellite instability at one microsatellite locus, 16% on two, and 13.3% on three loci. The percent of detected microsatellite instability for MSH2 gene was 14%, and for MLH1, it was 26%, for DVL3 22.9%, for AXIN1 17.8%, and for CDH1 8.3%. Since markers also allowed for the detection of loss of heterozygosity, gross deletions of MLH1 gene were found in 24% of meningiomas. Genetic changes between MLH1 and MSH2 were significantly positively correlated (p = 0.032). We also noted a positive correlation between genetic changes of MSH2 and DVL3 genes (p = 0.034). No significant associations were observed when MLH1 or MSH2 was tested against specific histopathological meningioma subtype or World Health Organization grade. However, genetic changes in DVL3 were strongly associated with anaplastic histology of meningioma (χ2 = 9.14; p = 0.01). Our study contributes to better understanding of the genetic profile of human intracranial meningiomas and suggests that meningiomas harbor defective cellular DNA mismatch repair mechanisms

Escherichia coli – from commensal organism to multiply resistant uropathogen

Escherichia coli sastavni je dio crijevne mikrobiote, no ujedno i najčešći uzročnik infekcija mokraćnog sustava. Brojni čimbenici virulencije mogu različito biti izraženi u različitim sojevima. Opisano je nekoliko uspješnih klonova ekstraintestinalne patogene E. coli (exPEC) koji su se raširili u mnogim krajevima svijeta. Ovi klonovi su zastupljeniji među uzročnicima cistitisa i pijelonefritisa negoli među izolatima iz stolice zdravih osoba, a češće nego sporadični klonovi pokazuju rezistenciju na jedan ili više antibiotika. Trimetoprim-sulfametoksazol je dugo vremena bio prvi lijek izbora u liječenju mnogih kategorija uroinfekcija. Zbog visoke rezistencije koja je bila očita već 1990-tih godina ovaj se antibiotik u mnogim dijelovima svijeta, pa i u Hrvatskoj više ne preporuča u empirijskoj terapiji infekcija mokraćnog sustava. Rezistencija na trimetoprim-sulfametoksazol je u Hrvatskoj iznad 20% i nije se bitno mijenjala posljednjih deset godina. Nasuprot tome, rezistencija na kinolone i beta-laktamske antibiotike u desetgodišnjem razdoblju pokazuje trend porasta. Hrvatska je 2011. g. prešla s američkih na europske standarde pri čemu je došlo do manjih pomaka u stopama rezistencije zbog administrativnog mijenjanja graničnih koncentracija za neke antibiotike. E. coli može akvirirati raznolike mehanizme rezistencije na svaki od antibiotika, pri čemu su, zbog lakše izmjene gena, izuzetno važni geni za rezistenciju koji se nalaze na plazmidima.Escherichia coli is an integral part of gut microbiota but at the same time it is the most frequent causative agent of urinary tract infections (UTI). Numerous virulence factors are variably expressed in different strains. Several successful clones of extraintestinal pathogenic E. coli (exPEC) have spread worldwide. These clones are more prevalent among causative agents of cystitis and pyelonephritis than among fecal isolates in healthy humans and they express resistance to one or more antibiotics more often than sporadic clones. Trimethoprime- sulfamethoxazole was the first line antibiotic for the treatment of several UTI categories for a long time. Due to high rates of resistance that became apparent in the 1990s this antibiotic is no more recommended in empirical therapy of UTI in many parts of the world, including Croatia. Resistance to trimethoprime-sulfamethoxazole is over 20 % in Croatia and this did not change over the last ten years. In contrast, resistance to quinolones and beta-lactams shows increasing trend over the past ten year period. In 2011 Croatia switched from American to European sensitivity testing standards which slightly influenced resistance rates. E. coli can acquire various resistance mechanisms to a variety of antibiotics. Plasmid mediated resistance mechanisms are especially important because of the ease of horizontal gene exchange

The rise and fall of resistant bacteria

Problem rezistencije bakterija na antibiotike jedan je od vodećih problema današnje medicine. Hrvatska sistematski prati stope rezistencije u najčešćih patogena od 1996. g. te je u ovom radu analizirano kretanje stopa rezistencije u Hrvatskoj u razdoblju od 2000. do 2014. g. Trideset pet hrvatskih mikrobioloških laboratorija (pokrivenost populacije >90 %) slalo je podatke o osjetljivosti kliničkih izolata (ponavljani izolati su isključivani) u Referentni centar Ministarstva zdravlja za praćenje rezistencije gdje su podaci agregirani i analizirani. Otpornost streptokoka grupe A na makrolide pokazuje lagani trend pada. Smanjena osjetljivost pneumokoka na penicilin pokazuje manje oscilacije bez izraženog trenda. Rezistencija na vankomicin je prisutna u E. faecium s trendom porasta u zadnje dvije godine. Rezistencija na cefalosporine 3. generacije i kinolone je u E. coli u blagom, ali stalnom porastu, a u K. pneumoniae je znatno viša, ali ne pokazuje porast zadnjih godina. Rezistencija na karbapeneme je u P. aeruginosa u blagom porastu, a u A. baumannii je naglo porasla od 2008. g. Hrvatska ima dobro organiziranu mrežu za praćenje rezistencije i poznavanje stopa rezistencije je važan prvi korak u kontroli širenja rezistencije. U kontroli širenja rezistencije također je bitno jačati ulogu timova za kontrolu bolničkih infekcija te prepustiti antimikrobnu terapiju timovima za rukovođenje antimikrobnom terapijom.Antimicrobial resistance (AMR) is one of the leading problems in modern medicine. Antibiotic resistance surveillance in Croatia was set up in 1996 and antibiotic resistance rates in most frequent bacterial pathogens were analysed for the period 2000 till 2014. Thirty five Croatian microbiology laboratories (population coverage >90 %) have sent antibiotic sensitivity data for clinical isolates (copy isolates were excluded) to the Ministry of Health Reference Center for Antibiotic Resistance Surveillance where these data were aggregated and analysed. Macrolide resistance in group Astreptococci shows a mild decreasing trend. Penicillin non-susceptibility in pneumococci demonstrates slight oscillations without any trend. Vancomycin resistance was recorded in Enterococcus faecium with increasing trend in the last two years. Resistance to 3rd generation cephalosporins and quinolones is slightly but constantly increasing in E. coli and in K. pneumoniae, although significantly higher, it does not demonstrate increase in the last few years. Carbapenem resistance is slightly increasing in P. aeruginosa and has abruptly increased in A. baumannii since 2008. Croatia has a well organized antibiotic resistance surveillance network and knowing local resistance rates is an important first step in controlling antibiotic resistance. For successful AMR control it is also very important to strengthen the role of infection control teams and to establish antibiotic stewardship teams

Structure and diversity of fish communities in the waters of the Drava River hydropower system

Uslijed tehnološkog napretka, riječni ekosustavi su najviše pogođeni izgradnjom brana i hidroelektrana. One pregrađuju rijeke i utječu na njihove tokove, mijenjajući pritom ekološke uvjete. Na Dravi u Hrvatskoj, zahvaljujući njenom hidroenergetskom potencijalu, izgrađena su tri hidroenergetska sustava. U svrhu utvrđivanja stanja ihtiopopulacije rijeke Drave, vršena su istraživanja na devet postaja hidroenergetskih sustava – Varaždin, Čakovec, Dubrava. Postaje i metode uzorkovanja i obrade su standardizirane, te daju sliku strukture ihtiopopulacije za svaku godinu od 1991. g. do 2010. g. Cilj rada bio je utvrditi promjene u strukturi ihtiopopulacija nastale nakon izgradnje triju hidroelektrana na rijeci Dravi. Raznolikost ihtiofaune je opisana pomoću alfa raznolikosti (indeksi raznolikosti, te grafički prikazi redoslijeda gustoća i K-dominantnosti) i beta raznolikosti (SHE analiza). Rezultati indeksa raznolikosti pokazuju da najveći broj vrsta ne znači nužno najveću ihtioraznolikost. Ukupna raznolikost ihtiofaune nije se znatnije promijenila tijekom cjelokupnog razdoblja istraživanja, ali se promijenila struktura zajednica. Akumulacijska jezera su stvorila nove zajednice lakustričkih vrsta riba s izraženom dominacijom.Due to technological progress, river ecosystems are most affected by hydropower plants and dams. They influence and divert the river's flow, changing ecological conditions at the same time. The river Drava, owing to its hydropower potential, has currently three hydropower systems in Croatia. For the purpose of determining ichthyofauna population in the river Drava, research was performed at nine stations of hydropower systems – Varaždin, Čakovec, Dubrava. Stations and sampling methods are standardised, so they represent ichthyofauna structure for every year in the period from 1991 to 2010. The purpose of this thesis is to define changes in ichthyofauna population, which are the result of construction of three hydropower plants on the river Drava. Diversity of ichthyofauna is described by alpha diversity (diversity indices, the K-dominance and the rank/abundance plot) and beta diversity (SHE analysis). Diversity indices results show us that the highest number of species doesn't mean the highest fish diversity. The total fish diversity hasn't significantly changed during the research period, but the structure of fish communities has changed. Hydropower plant reservoirs have created new lacustric species with expresive domination

The impact of E- and N-cadherin switch on phosphorylation status of beta-catenin and the epithelial-mesenchymal transition in intracranial meningiomas

Epitelno-mezenhimska tranzicija (EMT) koju karakterizira kadherinska izmjena, odnosno smanjena ekspresija E-kadherina, a pojačana N-kadherina, ima važnu ulogu u mehanizmima invazivnosti i metastaziranja tumorskih stanica. Klasični signalni put Wnt usko je povezan s procesima EMT, te je poznato da prijelaz β-katenina u jezgru može dovesti do EMT. U ovom istraživanju pokazano je da geni sudionici kadherinske izmjene, CDH1 i CDH2 imaju ulogu u progresiji meningeoma te je zabilježena viša ekspresija N-kadherina u odnosu na E-kadherin. Ekspresija transkripcijskih faktora SNAIL, SLUG i TWIST1 u meningeomima bila je izrazito jača od E- i N-kadherina, a SNAIL i SLUG su bili značajno povezani s višim gradusima (p=0,001) ukazujući na njihovu ulogu u progresiji. Viši gradusi bilježe i porast ekspresije ukupnog β-katenina koju prati i porast ekspresije njegovog aktivnog oblika (p=0,000). Istraživanje ove disertacije donosi prve rezultate genetičkih i proteinskih analiza važnih molekula signalnog puta Wnt i EMT te otkiva njihovu ulogu u intrakranijalnim meningeomima. Također, rezultati istraživanja nude smjernice i nove biljege progresije za buduća istraživanja te otkrivaju nove molekularne mete terapeutskih intervencija.Epithelial to mesenchymal transition (EMT), which is characterized by reduced expression of E-cadherin and increased expression of N-cadherin, plays an important role in the tumor invasion and metastasis. Classical Wnt pathway has a tight link with EMT and it has been shown that nuclear translocation of β-catenin can induce EMT. This research has showed that genes involved in cadherin switch, CDH1 and CDH2, play a role in meningioma progression. Also, increased expression of N-cadherin in relation to E-cadherin was recorded. In meningiomas, transcription factors SNAIL, SLUG, and TWIST1 demonstrated strong expression in relation to E- and N-kadherin. Expression of SNAIL and SLUG was significantly associated with higher grades (p=0,001) indicating their role in meningioma progression. Higher grades also recorded an increased expression of total β-catenin followed by an increased expression of its active form (p=0,000). This dissertation research brings the first results of genetic and protein analyzes of important molecules involved in WNT and EMT signaling pathways and reveals their role in intracranial meningiomas. Results of this research offer guidelines and new markers of progression for future research and reveal new molecular targets of therapeutic interventions

TWIST1 upregulation affects E-cadherin expression in brain metastases

Purpose: E-cadherin is a calcium-dependent glycoprotein whose main role is cell-cell adhesion. Its transcriptional repressor TWIST1 is a basic helix-loop-helix (bHLH) protein that participates in gastrulation and formation of mesodermal tissues during embryogenesis. In adult tissues, the high expression of TWIST1 induces the epithelial-mesenchymal transition (EMT)-a process in which cells become motile and able to metastasize. In this paper, we investigated the involvement of E-cadherin and TWIST1 in the carcinogenesis of brain metastases originating from two different primary sites-breast and lung. ----- Methods: The localization and expression of E-cadherin and its transcriptional repressor TWIST1 were investigated using a DAB-labeled streptavidin-horseradish peroxidase immunohistochemical reaction and specific monoclonal antibodies against TWIST1 and E-cadherin. Image J software was used for semi-quantitative analysis while H-score served for statistical evaluations. ----- Results: Immunohistochemistry showed that the expression of E-cadherin was downregulated in 85.7% of brain metastases, while at the same time, 82.2% of them showed upregulated TWIST1. Statistical analysis confirmed a significant negative correlation between expressions of TWIST1 and E-cadherin (p = 0.001). When the brain metastases expression levels were compared to primary breast tumors in corresponding patients, E-cadherin showed higher expression in primary pairs compared to corresponding metastases. Consistent to its role, TWIST1 was downregulated in all primary tumor samples in comparison to corresponding metastases pairs (p = 0.034). ----- Conclusion: This research provides valuable data regarding molecular events involving two EMT key components that could give directions for new possibilities for brain metastases diagnosis and treatment