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Morphodynamics of cape Pisak (Seline, Mala Paklenica)
No full textPredmet istraživanja ovog rada su morfološke promjene rta Pisak u mjestu Seline u općini Starigrad Paklenica i njegova morfodinamika. Opisana su prirodno-geografska obilježja šireg područja rta Pisak. U radu su analizirane kontinuirane promjene obalne linije od 60-ih godina 20. stoljeća do 2022. godine koristeći arhivske avio snimake (Državna Geodetska Uprava). Analize su napravljene pomoću ArcGIS Pro softvera. Temeljem napravljenih analiza promjena obalne linije, rt Pisak podijeljen je na četiri zone istraživanja gdje je uočena različita morfodinamika. Na cijelom području zabilježen je trend erozije žala, koji je većim dijelom posljedica antropogenih utjecaja ali je vrlo vjerojatno povezan i s izdizanjem relativne morske razne na širem području istraživanja.The subject of this study is the analysis of morphological changes of the cape Pisak in the village of Seline, as a part of the municipality of Starigrad Paklenica and its morphodynamics. The natural and geographical characteristics of the broader area of the cape Pisak are described. The study analyses the continuous changes in the shoreline position from the 1960s to 2022 using archival aerial photographs (State Geodetic Administration). The analyses were performed using ArcGIS Pro software. Based on the analysis of shoreline changes the cape Pisak was divided into four research zones with different morphodynamic properties. Throughout the area, a trend of shoreline erosion was observed, largely due to anthropogenic impacts on the cape Pisak but most probably also related to relative sea level rise
Nedostatak ergodičnosti kao novi mehanizam spontanog narušenja simetrije
No full textDisordered systems are characterized by global symmetries which can be explored through ensembles of matrices which respect these symmetries. Probability distributions of rotationally invariant matrix models are independent of the eigenvectors of said matrices. This leads to an apriori assumption that invariant matrix eigenvectors are randomly distributed across their vector space. There exists theoretical work on the breaking of this symmetry in eigenvector distributions for models which have disjoint eigenvalue support. In this thesis we present these arguments as well as reinforce them with numerical simulations in both the matrix space and the eigenvector/eigenvalue space of the problem. Finally, we present Anderson localization as a well-known effect in study of disordered systems and hint at possible application of the mentioned symmetry-breaking effect in construction of toy models for Anderson localization.Neuređeni sustavi karakterizirani su globalnim simetrijama koje se mogu istraživati putem ansambla matrica koje poštuju te simetrije. Distribucije vjerojatnosti rotacijski invarijantnih matričnih modela ne ovise o svojstvenim vektorima tih matrica. To dovodi do apriorne pretpostavke da su svojstveni vektori invarijantnih matrica nasumično raspoređeni u svom vektorskom prostoru. U literaturi postoji teorijski rad na temu narušavanja te simetrije u distribucijama svojstvenih vektora za modele s disjunktnom potporom svojstvenih vrijednosti. U ovom radu iznosimo argumente izložene u tom radu te ih dodatno potkrepljujemo numeričkim simulacijama u matričnom prostoru i prostoru svojstvenih vrijednosti/svojstvenih vektora. Na kraju predstavljamo Andersonovu lokalizaciju kao poznati efekt u području neuređenih sustava te ukazujemo na moguću primjenu spomenutog učinka narušavanja simetrije u konstrukciji pojednostavljenih modela Andersonove lokalizacije
Seasonal variability of microbial communities in the Palud salt swamp
No full textIako su močvare stoljećima promatrane kao bezvrijedna i nepotrebna područja u zadnjim se desetljećima
taj stav postepeno promijenio. Danas su močvarni ekosustavi prepoznati kao vrlo vrijedna staništa zbog
izuzetno visoke produktivnosti te zbog bogatstva vrsta od najsitnijih mikroorganizama pa sve do biljaka
i životinja. Cilj rada bio je istražiti sezonsku dinamiku autohtone mikrobne zajednice i fekalnih bakterija
u posebnim hidrografskim uvjetima voda slane močvare Palud i usporediti je sa morskom mikrobnom
zajednicom u neposrednoj blizini močvare. Područje posebnog ornitološkog rezervata Palud – Palù od
posebnog je značaja za sve organizme koje žive na tome području, a močvara koja se nalazi u samome
središtu rezervata je specifičan ekosustav na području sjevernog Jadrana. Uzorkovanje se je izvodilo na
9 prethodno određenih postaja, na području posebnog ornitološkog rezervata Palud – Palù, a održalo se
je 7 puta u periodu od kraja srpnja 2021., do svibnja 2022. Određena je sanitarna kakvoća vode te
brojnost autohtone mikrobne zajednice u močvari, moru te u močvarnom kanalu koji povezuje močvaru
s morem. Također je napravljena i statistička analiza podataka radi prikaza korelacije između
sezonalnosti i mjerenih abiotičkih čimbenika, kao i grupacija postaja ovisno o poziciji uzorkovanja i
ovisno o prisutnosti indikatorskih mikroorganizama ili autohtone mikrobne zajednice. Tijekom toplijih
mjeseci (ljeto 2021. i proljeće 2022.) koncentracija indikatora fekalnog onečišćenja, ali i brojnost
autohtone mikrobne zajednice je bila veća nego tijekom hladnijih mjeseci (jesen 2021. i zima 2022.).
Dobiveni rezultati uspoređeni su s prosječnim podacima za sjeverni Jadran dostupnim u literaturi, kao i
s dugoročnim prosjecima podataka za postaju RV001 na 1 NM zapadno od Rovinja. Rezultati su
pokazali da hidrografski parametri u močvari imaju velike sezonske oscilacije, ali i da morske mijene
imaju izuzetno važnu ulogu u funkcioniranju mikrobne zajednice i čitavog ekosustava.Although wetlands have been viewed as worthless and unnecessary areas for centuries, this attitude has
gradually changed in recent decades. Today, wetland ecosystems are recognized as very valuable
habitats due to their extremely high productivity and the richness of species, from the smallest
microorganisms to plants and animals. The aim of this research is to investigate the seasonal dynamics
of the indigenous microbial community and fecal bacteria in the special hydrographic conditions of the
waters of the Palud salt marsh and compare it with the marine microbial community in the immediate
vicinity of the marsh. The area of the special ornithological reserve Palud - Palù is of special importance
for all organisms that live in that area, and the marsh located in the very center of the reserve is a specific
ecosystem in the area of the northern Adriatic. Sampling was carried out at 9 previously determined
stations, in the area of the special ornithological reserve Palud - Palù and took place 7 times in the period
from the end of July 2021 to May 2022. The sanitary quality of the water and the abundance were
determined autochthonous microbial communities in the marsh, the sea and in the marsh channel that
connects the marsh with the sea. A statistical analysis of the data was also made to show the correlation
between seasonality and measured abiotic factors, as well as the grouping of stations depending on the
sampling position and depending on the presence of indicator microorganisms or autochthonous
microbial communities. During the warmer months (summer 2021 and spring 2022), the concentration
of fecal pollution indicators, as well as the abundance of the autochthonous microbial community, was
expected to be higher than during the colder months (autumn 2021 and winter 2022). The obtained
results were compared with average data for the northern Adriatic available in the literature, as well as
with long-term data averages for station RV001 at 1 NM west of Rovinj. The results showed that
hydrographic parameters in the marsh have large seasonal oscillations, but also that sea changes play an
extremely important role in the functioning of the microbial community and the entire ecosystem
Genska raznolikost i filogeografija riba roda Gobio (Gobionidae) i njihovih ektoparazita roda Gyrodactylus (Platyhelminthes: Monogenea) u Hrvatskoj i Austriji
No full textFreshwater fishes of the genus Gobio are widely distributed in Eurasia, where they show great
phenotypic similarity between different species, but also considerable intraspecific morphological
variability. The genetic research so far showed that there is also a remarkable genetic diversity
present within the genus, and that Gobio is genetically very diverse in the Danube River drainage.
This research aimed at exploring the genetic diversity and phylogeography of Gobio in Croatia and
Austria through DNA barcoding, and additionally investigating the diversity of ectoparasites of the
genus Gyrodactylus which reside on Gobio, potentially enhancing our understanding of the host’s
phylogeographic patterns through insights from the parasites’. The results of this research
uncovered the presence of the new mitochondrial lineage of Gobio in Croatia, which is closely
related to other southeast European Gobio species, and a distinct phylogeographic pattern within
the genus in Austria and Croatia. The parasites of the genus Gyrodactylus also showed great
diversity, with several new lineages uncovered, but without a clear phylogeographic structure.
Furthermore, the phylogenetic analysis indicates that Gyrodactylus colonized fishes of the genus
Gobio in the Danube River drainage twice independently.Slatkovodne ribe roda Gobio široko su rasprostranjene u Euroaziji, gdje pokazuju veliku fenotipsku
sličnost među vrstama, ali također značajnu intraspecijsku morfološku varijabilnost. Genska
istraživanja dosad provedena na ovim ribama pokazala su da unutar roda postoji velika genska
raznolikost i da je ta raznolikost izražena kod pripadnika roda Gobio u dunavskom slijevu. Cilj
ovog istraživanja bio je istražiti gensku raznolikost i filogeografiju roda Gobio u Hrvatskoj i
Austriji primjenom DNA barkodiranja te istražiti raznolikost ektoparazita roda Gyrodactylus, koji
se mogu pronaći na spomenutim ribama, s ciljem boljeg razumijevanja filogeografskih uzoraka
domaćina uvidom u filogeografske uzorke parazita. Rezultati ovog istraživanja otkrivaju u
Hrvatskoj dosad nepoznatu mitohondrijsku liniju riba roda Gobio, koja je u bliskom srodstvu s
drugim vrstama roda Gobio iz jugoistočne Europe te da je prisutan filogeografski uzorak među
pripadnicima ovog roda u Austriji i Hrvatskoj. Paraziti roda Gyrodactylus su također pokazali
veliku gensku raznolikost te su otkrivene nove genske linije tog roda, međutim nije utvrđeno
postojanje jasne filogeografske strukture. Ipak, filogenetska analiza ukazuje na to da su paraziti tog
roda dvaput neovisno kolonizirali ribe roda Gobio u dunavskom slijevu
Establishment of human cell lines with endogenous expression of protein tubulin fluorescently tagged using the CRISPaint method
No full textZa promatranje procesa unutar žive stanice, većinom se koristi fluorescencijska mikroskopija.
Glavni zahtjev fluorescencijske mikroskopije je to da željeni predmet proučavanja u stanici
mora fluorescirati. Jedan od načina za promatranje stanice pod fluorescencijskim mikroskopom
je da se stanični proteini obilježe fluorescentnim proteinima. Međutim, egzogeno unešene
sekvence za fuzionirane proteine generiraju proteine s neprirodnom razinom ekspresije, a
endogeni protein ostaje neobilježen. Endogeno obilježavanje staničnih proteina s
fluorescentnim proteinima jedan je od načina za njihovu vizualizaciju bez utjecaja na jačinu
ekspresije. Tehnologija CRISPR-Cas (engl. Clustered Regularly Interspaced Short
Palindromic Repeats) često je korištena u genetičkom inženjerstvu za jednostavno i precizno
uređivanje genoma. U ovom radu je korištena novo razvijena metoda CRISPaint (engl.
CRISPR-assisted insertion tagging). To je sustav koji uz pomoć tehnologije CRISPR-Cas
omogućava ugradnju gena za fluorescentni protein u genom tj. u ciljanu sekvencu gena, da bi
se proizveo endogeni protein obilježeni fluorescentnim biljegom. Optimizirala sam protokol za
transfekciju uz pomoć plazmida sustava CRISPaint-a i uspostavila sam dvije ljudske stanične
linije, HeLa i RPE1, s endogeno obilježenim proteinom tubulinom sa zelenim fluorescentnim
proteinom. Ove stanične linije se dalje mogu koristiti za promatranje stanične diobe pod
fluorescencijskim mikroskopom, a metoda CRISPaint se može primijeniti za endogeno
obilježavanje i drugih proteina od interesa.Fluorescence microscopy is used to observe processes inside a living cell and its main
requirement is that the desired object of study in the cell must fluoresce. One way to observe a
cell under a fluorescence microscope is to label cellular proteins with fluorescent proteins (FP).
However, exogenously introduced sequences for fusion proteins produce proteins with
unnatural expression levels while the endogenous protein remains unlabeled. Endogenous
labeling of cellular proteins with FP is one way to visualize them without affecting the strength
of expression. CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats)
technology is today often used in genetic engineering to simply and precisely edit the genome.
In this work, the newly developed method CRISPaint (CRISPR-assisted insertion tagging) was
used. It is a system that, using CRISPR-Cas technology, enables the incorporation of a gene for
FP into the genome in order to produce an endogenous fluorescently tagged protein. I optimized
the transfection protocol using CRISPaint system plasmids and established two human cell
lines, HeLa and RPE1, with endogenously labeled protein tubulin with green FP. These cell
lines can be used to observe cell division under a fluorescence microscope and the CRISPaint
method can be applied for endogenous labeling of other proteins
Diversity of vegetative compatibility types of fungus Cryphonectria parasitica and genetic analysis of ORFA region of Cryphonectria hypovirus 1 in populations of Istria and Cres island
No full textGljiva Cryphonectria parasitica uzrokuje bolest rak kore pitomog kestena (Castanea sativa),
te je u proteklom stoljeću ugrozila šume pitomog kestena diljem Europe. Prisutnost virusa
Cryphonectria hypovirus 1 (CHV1) u populacijama gljive povezana je sa smanjenjem
virulentnosti i blažim tijekom bolesti raka kore kestena, tj. tijekom vremena dolazi do
uspostavljanja prirodne biološke kontrole bolesti. Kako bi se razumjela sama raznolikost gljive,
analizirani su tipovi vegetativne kompatibilnosti (vc) ove gljive. U ovom istraživanju utvrđena
je raznolikost istraživanih populacija pomoću Shannonovog indeksa (H') koji u populaciji
gljive otoka Cresa iznosi 1,52, a u populaciji Istre 1,33. U populaciji C. parasitica otoka Cresa
potvrđeno je šest različitih EU tipova, dok je u populaciji Buje, Istra potvrđeno pet. Također,
50% izolata gljive populacije otoka Cresa sadrži virus CHV1, dok u populaciji Istre virus nije
nađen. Računalnom analizom sekvenci virusne RNA u creskoj populaciji gljive nađeno je devet
haplotipova virusa. Analizirane sekvence virusa CHV1 imaju ukupno 39 polimorfizama u 985
nukleotida, te je potvrđeno da CHV1 u populaciji Cresa pripada talijanskom podtipu.Fungus Cryphonectria parasitica causes the chestnut blight disease in sweet chestnut
(Castanea sativa) and has endangered the forests of sweet chestnut across Europe in the last
century. The presence of Cryphonectria hypovirus 1 (CHV1) in fungal populations is
connected to the reduction of the fungus’ virulence and a milder disease progress of chestnut
blight, or in other words, a natural biological control is established over time. In order to
understand the diversity of C. parasitica populations, an analysis of its vegetative compatibility
(vc) types has been carried out. In this research, the diversity of the analysed populations was
determined using the Shannon Diversity Index (H’), which was determined to be 1.52 in the
fungal population of the island Cres, and 1.33 in the population of Buje, Istria. In the population
of the C. parasitica of the island Cres six different EU-types were found, whereas in the
population of Istria there were five. Moreover, 50% of the fungal isolates in the population of
the island Cres were infected with the CHV1 virus, while in the population of Istria the virus
was not found. By analysing CHV1 viral sequences in the population of Cres nine CHV1
haplotypes were found. Analysed sequences of the CHV1 virus have 39 polymorphisms in 985
nucleotides in total, and it has been determined that the CHV1 in the population of Cres belongs
to the Italian subtype of the virus
Design and preparation of imidazole, pyrazole and 5-methylisatin acetylcholinesterase reactivators
No full textU ovom diplomskom radu sintetizirana su tri prekursora Ugijeve reakcije koji sadrže oksimsku
i karboksilnu skupinu: 6-(2-hidroksiiminometilimidazol-1-il)heksanska kiselina, 2-(4-
hidroksiiminometil-pirazol-1-il)heksanska kiselina i 7-(5-metil-3-(hidroksiimino)-2-
oksoindolin-1-il)heksanska kiselina. Dobiveni 5-metilisatinski prekursor poslužio je kao
reaktant za Ugijevu reakciju s benzil-aminom, tert-butil-izocijanidom i formaldehidom pri
čemu se usporedila mogućnost izvođenja sinteze u otopini, mikrovalnom reaktoru te
mehanokemijski. Pripravljeni spojevi pročišćeni su dostupnim kromatografskim tehnikama i
karakterizirani dostupnim analitičkim metodama (UPLC-UV/MS, 1D, 2D NMR). U
računalnom dijelu rada uspoređeno je vezanje produkta Ugijeve reakcije i literaturno opisanih
reaktivatora u aktivnom mjestu sarinom inhibiranoga enzima acetilkolinesteraze pomoću
molekulskog uklapanja.In this diploma thesis new Ugi reaction's precursors containing oxime and carboxyl groups were
synthesized: 6-(2-hydroxyiminomethylimidazol-1-yl)hexanoic acid, 2-(4-
hydroxyiminomethyl-pyrazol-1-yl)hexanoic acid and 7-(5-methyl-3-(hydroxyimino)-2-
oxoindolin-1-yl)hexanoic acid. The 5-methylisatin precursor was used as a reactant for the Ugi
reaction with benzyl-amine, tert-butyl-isocyanide and formaldehyde. Besides the classical
syntheses in solution, the Ugi reaction was performed in a microwave reactor as well as
mechanochemically. The compounds were purified by available chromatographic techniques
and characterized by available analytical methods (UPLC-UV/MS, 1D, 2D NMR). The binding
of the Ugi reaction's products and acetylcholinesterase reactivators in the active site of the sarininhibited enzyme acetylcholinesterase were compared by molecular docking
Differences in coloration of the sympatric Dalmatian wall lizard (Podarcis melisellensis) and Italian wall lizard (Podarcis siculus)
No full textKrška gušterica (Podarcis melisellensis) i primorska gušterica (Podarcis siculus) dvije su
simpatrijske vrste gušterica iz porodice Lacertidae. U Hrvatskoj su rasprostranjene na području
jadranske obale i otoka, a ako se nađu na istom staništu u kompeticijskom su odnosu. U
populacijama obje vrste primjetan je spolni dimorfizam u izgledu i obojenju.. Cilj ovog rada
bio je utvrditi obojenje karakteristično za svaku vrstu, kao i za svaki spol unutar vrste.
Istraživanje je provedeno na ukupno 60 jedinki, 15 mužjaka i 15 ženki svake vrste, ulovljenima
na tri kopnene lokacije - Knin, Pag i Sinj. Za određivanje boja na tijelu guštera korištena je
spektrofotometrijska analiza. Analizirana je razlika u dorzalnim i lateralnim bojama vezanim
uz kriptičnost – zelena boja na leđima i smeđa boja na bočnoj strani tijela i stražnjem dijelu
leđa te razlika u lateralnim i ventralnim bojama vezanim uz intraspecijsku komunikaciju –
plava boja ljuski bočne strane tijela te boja vrata i boja prsa. Prema dobivenim rezultatima
istraživanja može se zaključiti da kod boja vezanih uz kriptičnost sličnost između vrsta postoji
kod smeđih boja dorzalne i bočne strane tijela. Razlika između vrsta postoji kod boja vezanih
uz intraspecijsku komunikaciju, krška gušterica pokazuje veći udio žute i zelene boje na vratu
u odnosu na pripadnike vrste primorske gušterice. Spolni dimorfizam unutar vrste izražen je
kod krške gušterice gdje mužjaci imaju zeleniju boju leđa, a ženke žuće obojenje prsa. Mužjaci
obje vrste pokazuju plavije obojenje ljuski bočne strane tijela u odnosu na ženke.The Dalmatian wall lizard (Podarcis melisellensis) and the Italian wall lizard (Podarcis
siculus) are two sympatric species from the Lacertidae family. In Croatia they are widespread
on the Adriatic coast and islands. They are in a competitive relationship when found in the
same habitat. Sexual dimorphism in appearance and coloration is noticeable in the populations
of both species. This study aimed to determine characteristic coloration for each species as well
as for each sex within the species. The research was conducted on a total of 60 individuals, 15
males and 15 females of each species caught in three mainland locations - Knin, Pag and Sinj.
Spectrophotometric analysis was used to determine the colors on the lizard's body. We
analyzed difference in dorsal and lateral colors related to crypticity – green and brown color
on the back and brown color on the side of the body and the difference in lateral and ventral
colors related to intraspecies communication – blue color of outer ventral scales and neck and
chest color. According to the results, it can be concluded that there is a similarity between the
species, it exists in colors related to crypticness – brown colors of the dorsal and lateral sides
of the body. Difference between the species exists in the colors related to intraspecies
communication, the Dalmatian wall lizard shows greater proportion of yellow and green color
on the neck compared to members of the Italian wall lizard. Sexual dimorphism within the
species is expressed in the Dalmatian wall lizard where males have a greener back and females
a yellower chest. Males of both species show a bluer coloration of outer ventral scales
compared to female
Macrogeomorphological regionalisation of fauna diversity in achialine caves of the Eastern Adriatic Sea coast
No full textAnhijaline špilje pripadaju specifičnim speleološkim fenomenima Mediteranskog krša. Tijekom
protekla četiri desetljeća istraživanja anhijalinih špilja u Hrvatskoj enormno su se proširila i
intenzivirala. Međutim, ukupna zajednica vodenih beskralješnjaka ostala je nedovoljno poznata.
Istraživanje zajednica je provedeno na 99 uzoraka prikupljenih u 39 anhijalinih špilja tijekom svih
sezona u razdoblju od rujna 2001. do svibnja 2011. godine kako bi se analizirala struktura i
raznolikost vodenih beskralješnjaka te opisale razlike između četiri Makrogeomorfološke regije
Hrvatske definirane prema Bognaru i sur. (2012). Zabilježeno je ukupno 46 svojti vodenih
beskralješnjaka unutar šest koljena. Najdominantniji predstavnici jadranske anhijalne špiljske
faune bili su člankonošci ili točnije rakovi. Identificirali smo vruće točke bioraznolikosti, Vodenu
jamu na otoku Gustac u Kornatskom arhipelagu u makrogeomorfološkoj regiji 2.3. SZ Dalmacija
s arhipelagom. Makrogeomorfološka regija od posebnog interesa za zaštitu je 2.3. SZ Dalmacija s
arhipelagom unutar koje je zabilježen najveći ukupni broj vodenih beskralježnjaka u istraživanim
anhijalinim špiljama, te najveći broj špilja (ukupno četiri) s velikim brojem svojti vodenih
beskralješnjaka (≥15).Anchialine caves belong to the specific speleological phenomenon in the Mediterranean karst. Over
the last four decades, research on the anchialine caves in Croatia has expanded enormously.
However, total anchialine aquatic invertebrate assemblages remain poorly understood. The
assemblages were determined from 99 samples collected in 39 anchialine caves during seasonal
surveys carried out from September 2001 to May 2011 to analyze the structure and diversity of
aquatic invertebrate assemblages and to describe the differences between four
Macrogeomorphological regions of Croatia according to Bognar et al. (2012). A total of 46 taxa of
invertebrates in six phyla were identified. The most dominant representatives of the Adriatic
anchialine cave fauna were arthropods or, more precisely, crustaceans. We identified a hotspot of
biodiversity the pit Vodena jama on the island Gustac in Kornati Archipelago in the
Macrogeomorphological region 2.3. NW Dalmatia with archipelago. Macrogeomorphological
region of particular interest for protection is 2.3. NW Dalmatia with the archipelago within which
the largest total number of aquatic invertebrates were recorded in the investigated anchialine caves,
and the largest number of caves (four in total) with a large number of aquatic invertebrate taxa
(≥15)
Mechanisms regulating the CRISPR-Cas system in Escherichia coli
No full textSustav CRISPR-Cas je adaptivni imunosni sustav za obranu prokariota od stranih genetičkih
elemenata. Regulacija sustava CRISPR-Cas u bakteriji E. coli je kompleksna i nije u potpunosti
razjašnjena. Poznato je da protein H-NS djeluje na razini transkripcije, šaperon HtpG na razini
post-translacije, dok temperatura utječe na aktivnost proteina Cas3 na nepoznati način. U ovom
radu su detaljnije istraženi mehanizmi regulacije aktivnosti sustava CRISPR-Cas na razini
transkripcije i post-translacije. Praćenjem otpornosti stanica na infekciju fagom λvir i
određivanjem količine transkripata gena cas utvrđeno je da protein StpA može inhibirati
promotore Pcas8e i anti-Pcas u nedostatku proteina H-NS, te da pojačana ekspresija ili
inaktivacija proteaze Lon u mutantu hns aktivira zaštitu od infekcije neovisno o sustavu
CRISPR-Cas. Na aktivnost proteina Cas3 utječe ''anti-sense'' mRNA na nepoznat način, dok
temperatura uzrokuje alosteričku promjenu konformacije ovog proteina čime se inhibira
njegova nukleazna aktivnost. Šaperon HtpG nije utjecao na količine proteina Cas3, već
vjerojatno na zauzimanje njegove pravilne konformacije.The CRISPR-Cas system is a prokaryotic adaptive immune system that provides defense
against foreign DNA. The regulation of the CRISPR-Cas system in E. coli is complex and not
fully understood. The repressor H-NS acts at the transcriptional level, HtpG posttranslationally, while the activity of Cas3 is affected by temperature in an unknown way. The
aim of this research was to further elucidate the mechanisms regulating the activity of the
CRISPR-Cas system at the transcriptional and post-translational level. Phage sensitivity assays
and quantification of cas transcripts showed that StpA can inhibit Pcas8e and anti-Pcas
promoters in the absence of H-NS. Overexpression or inactivation of Lon protease in hns
mutants provides protection against phage infection independent of CRISPR-Cas. Cas3 protein
activity is affected by an "anti-sense" mRNA in an unknown way, while allosteric change in
Cas3 structure by temperature inhibits its nuclease activity. HtpG did not affect Cas3 levels, but
the acquisition of the correct conformation