Ancient DNA – history of life

Drevna DNA predmet je mnogih istraživanja današnjice. Intrigira brojne znanstvenike koji proučavaju genetički materijal povijesnih ostataka kako bi interpretirali njihovo biološko i socijalno značenje. Osnovna svrha tih istraživanja je shvaćanje evolucijske povijesti života. Ovaj rad prikazuje postepen razvoj ovog aspekta u znanosti kroz lepezu različitih istraživanja koja su dovela do usavršavanja metoda rada s drevnom DNA i revolucijom na području molekularne genetičke evolucije. Također, obrađen je i problem degradacije i kontaminacije DNA uzoraka koji je glavni limitirajući faktor u istraživanjima. Napravljen je osvrt i na ulogu drevne DNA u modernoj znanosti.Ancient DNA is a subject of many researches today. It arouses interest of many scientists who explore genetic material of ancient remains to interprete their biological and social meaning. The basic purpose of these studies is to understand evolutional history of life. This paper presents development of this aspect in science thanks to many different studies that resulted in improvement of aDNA methods and revolution in understanding molecular genetic evolution. Degradation and contamination of aDNA, which is limiting factor during researches, is disscused. A review of the role of ancient DNA in modern science is given in this paper, too

The infulence of tufa deposition on macroalgae and epiphytic in Lake Prošće

Biomineralizacija je proces kojim organizmi stvaraju ili sudjeluju u stvaranju minerala. Prisutna je među različitim skupinama organizama, no, eventualne posljedice njenog postojanja u ekološkom kontekstu još uvijek nisu najjasnije. U ovom istraživanju je kao model za proučavanje utjecaja biomineralizacije na epifitsku faunu uzeta alga roda Chara čiji su primjerci skupljeni s dubina od 1, 5 i 10 metara u Prošdanskom jezeru koje se nalazi u sklopu sedrotvornog sustava NP Plitvička jezera. Analiza epifitske faune je pokazala visoku raznolikost, a njena brojnost je negativno korelirana s količinom taloga sedre na površini talusa. Analiza izotopa 13C i 18O taloga sedre je dala naslutiti da je sedra istaložena na površini talusa alge rezultat biološke aktivnosti, odnosno, fotosinteze, što podupire činjenicu da se na površini alge roda Chara događa proces biomineralizacije. Spektrofotometrijskim određivanjem količine fotosintetskih pigmenata u tkivu alge je uočeno smanjenje omjera klorofil a : klorofil b i povećanje omjera klorofil a : karotenoidi sa smanjenjem dubine jezera. To je najvjerojatnije rezultat aktivacije mehanizama za efikasnije iskorištavanje svjetlosti i zaštitu od potencijalno štetnog zračenja. Također, uočena je statistički značajna korelacija između količine fotosintetskih pigmenata i udjela sedre na površini talusa.Biomineralization is the process by which organisms create or participate in creating a mineral. It is widespread among different groups of organisms. However, consequences that this process has in ecological context are still not clear. Alga of genus Chara was the model organism in this research where effect of biomineralization on epiphitic fauna was studied. Alga was collected in Lake Prošde which is a part of tufa depositing system Plitvice lakes at depths of 1, 5 and 10 meters. Analysis of epiphitic fauna showed high diversity, and its abundance was negatively correlated with tufa deposits on the surface of the talus. Analysis of the isotops 13C and 18O of tufa deposits indicates that tufa deposits on the surface of the talus are a result of biological activity. Spectrophotometric measurements of the amount of photosynthetic pigments in algal talus showed decrease in the ratio chlorophill a : chlorophill b and increase in the ratio chlorophill a : carotenoids with decreasing depth of the lake. This is most likely a result of the mechanisms which tend to increase efficiency of light utilization and protect alga from potentially harmful radiation. Also, amount of photosynthetic pigments and amount of tufa deposited on algal surface showed statistically significant correlation

Ancient DNA – history of life

Drevna DNA predmet je mnogih istraživanja današnjice. Intrigira brojne znanstvenike koji proučavaju genetički materijal povijesnih ostataka kako bi interpretirali njihovo biološko i socijalno značenje. Osnovna svrha tih istraživanja je shvaćanje evolucijske povijesti života. Ovaj rad prikazuje postepen razvoj ovog aspekta u znanosti kroz lepezu različitih istraživanja koja su dovela do usavršavanja metoda rada s drevnom DNA i revolucijom na području molekularne genetičke evolucije. Također, obrađen je i problem degradacije i kontaminacije DNA uzoraka koji je glavni limitirajući faktor u istraživanjima. Napravljen je osvrt i na ulogu drevne DNA u modernoj znanosti.Ancient DNA is a subject of many researches today. It arouses interest of many scientists who explore genetic material of ancient remains to interprete their biological and social meaning. The basic purpose of these studies is to understand evolutional history of life. This paper presents development of this aspect in science thanks to many different studies that resulted in improvement of aDNA methods and revolution in understanding molecular genetic evolution. Degradation and contamination of aDNA, which is limiting factor during researches, is disscused. A review of the role of ancient DNA in modern science is given in this paper, too

Scanning electron microscopy of human islet cilia

Human islet primary cilia are vital glucose-regulating organelles whose structure remains uncharacterized. Scanning electron microscopy (SEM) is a useful technique for studying the surface morphology of membrane projections like cilia, but conventional sample preparation does not reveal the submembrane axonemal structure, which holds key implications for ciliary function. To overcome this challenge, we combined SEM with membrane-extraction techniques to examine primary cilia in native human islets. Our data show well-preserved cilia subdomains which demonstrate both expected and unexpected ultrastructural motifs. Morphometric features were quantified when possible, including axonemal length and diameter, microtubule conformations, and chirality. We further describe a ciliary ring, a structure that may be a specialization in human islets. Key findings are correlated with fluorescence microscopy and interpreted in the context of cilia function as a cellular sensor and communications locus in pancreatic islets

Prvo sistematsko istraživanje adulta i drugi popis tulara (Insecta, Trichoptera) za područje Nacionalnog parka Plitvička jezera s osvrtom na povijest istraživanja, bioraznolikost, rasprostranjensot i ekologiju

The Plitvice Lakes National Park is a unique area in the world with a great variety of aquatic habitats, including tufa barriers. UNESCO has protected this area since 1979. In this paper, detailed faunistic results of the first research on Trichoptera species conducted from 1997 to 2001 are shown. Sampling was done using both light and emergence traps, and 77 caddisfly species were determined using the two methods. Furthermore, a brief overview of the Trichoptera research history in the Plitvice Lakes area is given along with a detailed presentation of caddisfly fauna and an extended checklist of Trichoptera species. In the Plitvice Lakes 89 Trichoptera species have been recorded so far. Flight periods are given for each species. Also, the reasons of such a high degree of Trichoptera biodiversity (the highest in Croatia) in the Plitvice Lakes are highlighted. A comparison of species assemblages collected from the 12 localities was made along with the comparison of Trichoptera fauna composition in different aquatic habitats in the Plitvice Lakes NP: springs, streams, lakes and tufa barriers.Plitvička jezera jedinstveno su područje u svijetu s velikom raznolikošću slatkovodnih staništa od kojih se posebno ističu sedrene barijere. Ovo je područje pod zaštitom UNESCO-a od 1979. godine. Radom se prikazuju detaljni faunistički rezultati prvih sistematskih istraživanja tulara (Trichoptera, Insecta) na području Nacionalnog parka Plitvička jezera. Tulari su prikupljani metodama svjetlosnih i emergencijskih klopki u periodu od 1997. do 2001. godine, a zabilježeno je ukupno 77 vrsta. U radu se daje osvrt na povijest istraživanja tulara na području Nacionalnog parka, detaljan pregled faune tulara zabilježene na tome području te prikaz drugog, nadopunjenog popisa Trichoptera NP Plitvička jezera. Na području Nacionalnog Parka dosadašnjim je istraživanjima zabilježeno 89 vrsta tulara. Za sve vrste prikazuje se period leta te se ukazuje na razloge ovako velike bioraznolikosti tulara (najveća u Hrvatskoj) na području Plitvička jezera. Izvršena je usporedba zabilježene faune na svim lokalitetima istraživanja (12 lokaliteta) na području Plitvičkih jezera, te usporedba sastava faune tulara na različitim slatkovodnim tipovima staništa na tome prostoru: izvorima, potocima, jezerima i sedrenim barijerama

Epithelial abnormalities in the small intestine of Zambian children with stunting

BACKGROUND: Environmental enteropathy (EE) contributes to impaired linear growth (stunting), in millions of children worldwide. We have previously reported that confocal laser endomicroscopy (CLE) shows fluorescein leaking from blood to gut lumen METHODS: We performed confocal laser endomicroscopy (CLE) in 75 children and collected intestinal biopsies for histology in 91 children. CLE videos were evaluated, employing the Watson score to determine severity of leakiness. Morphometry was carried out on well-orientated mucosa and 3 biopsies were examined by electron microscopy. RESULTS: Confocal laser endomicroscopy demonstrated substantial leakage from circulation to gut lumen in 73 (97%) children. Histology consistently showed characteristic changes of EE: villus blunting, lamina propria and epithelial inflammation, and depletion of secretory cells (Paneth cells and goblet cells). Epithelial abnormalities included marked variability in epithelial height, disorganised and shortened microvilli, dilated intercellular spaces, pseudostratification, formation of synechiae between epithelium on adjacent villi, crypt destruction, and abundant destructive lesions which may correspond to the microerosions identified on CLE. CONCLUSION: Epithelial abnormalities were almost universal in Zambian children with non-responsive stunting, including epithelial microerosions, cell-cell adhesion anomalies, and defects in secretory cells which may all contribute to impairment of mucosal barrier function and microbial translocation

SARS-CoV-2 infects human engineered heart tissues and models COVID-19 myocarditis

There is ongoing debate as to whether cardiac complications of coronavirus disease-2019 (COVID-19) result from myocardial viral infection or are secondary to systemic inflammation and/or thrombosis. We provide evidence that cardiomyocytes are infected in patients with COVID-19 myocarditis and are susceptible to severe acute respiratory syndrome coronavirus 2. We establish an engineered heart tissue model of COVID-19 myocardial pathology, define mechanisms of viral pathogenesis, and demonstrate that cardiomyocyte severe acute respiratory syndrome coronavirus 2 infection results in contractile deficits, cytokine production, sarcomere disassembly, and cell death. These findings implicate direct infection of cardiomyocytes in the pathogenesis of COVID-19 myocardial pathology and provides a model system to study this emerging disease

Transcriptomic atlas and interaction networks of brain cells in mouse CNS demyelination and remyelination

Demyelination is a hallmark of multiple sclerosis, leukoencephalopathies, cerebral vasculopathies, and several neurodegenerative diseases. The cuprizone mouse model is widely used to simulate demyelination and remyelination occurring in these diseases. Here, we present a high-resolution single-nucleus RNA sequencing (snRNA-seq) analysis of gene expression changes across all brain cells in this model. We define demyelination-associated oligodendrocytes (DOLs) and remyelination-associated MAF

Gold nanoparticle-enhanced X-ray microtomography of the rodent reveals region-specific cerebrospinal fluid circulation in the brain

Cerebrospinal fluid (CSF) is essential for the development and function of the central nervous system (CNS). However, the brain and its interstitium have largely been thought of as a single entity through which CSF circulates, and it is not known whether specific cell populations within the CNS preferentially interact with the CSF. Here, we develop a technique for CSF tracking, gold nanoparticle-enhanced X-ray microtomography, to achieve micrometer-scale resolution visualization of CSF circulation patterns during development. Using this method and subsequent histological analysis in rodents, we identify previously uncharacterized CSF pathways from the subarachnoid space (particularly the basal cisterns) that mediate CSF-parenchymal interactions involving 24 functional-anatomic cell groupings in the brain and spinal cord. CSF distribution to these areas is largely restricted to early development and is altered in posthemorrhagic hydrocephalus. Our study also presents particle size-dependent CSF circulation patterns through the CNS including interaction between neurons and small CSF tracers, but not large CSF tracers. These findings have implications for understanding the biological basis of normal brain development and the pathogenesis of a broad range of disease states, including hydrocephalus

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis.

There is ongoing debate as to whether cardiac complications of coronavirus disease-2019 (COVID-19) result from myocardial viral infection or are secondary to systemic inflammation and/or thrombosis. We provide evidence that cardiomyocytes are infected in patients with COVID-19 myocarditis and are susceptible to severe acute respiratory syndrome coronavirus 2. We establish an engineered heart tissue model of COVID-19 myocardial pathology, define mechanisms of viral pathogenesis, and demonstrate that cardiomyocyte severe acute respiratory syndrome coronavirus 2 infection results in contractile deficits, cytokine production, sarcomere disassembly, and cell death. These findings implicate direct infection of cardiomyocytes in the pathogenesis of COVID-19 myocardial pathology and provides a model system to study this emerging disease