Utjecaj akarboze na katalitičke aktivnosti alanin aminotransferaze i aspartat aminotransferaze u jetri kontrolnih i dijabetičnih CBA miševa

The purpose of this study was to examine the short-term effects of diet containing 0.1% (m/m) of acarbose in standard laboratory chow on specific liver enzyme activities: alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in control and diabetic CBA mice. Diabetes was induced by intravenous injection of alloxan monohydrate in a dose of 75 mg kg-1 mouse body mass seven days before the treatment with acarbose. There were four groups of CBA mice in the experiment: control (C) mice (n = 6) and diabetic (D) mice (n = 8) fed standard chow; control (C/A-100) mice (n = 8) and diabetic (D/A-100) mice (n = 8) fed standard chow containing 0.1% acarbose. Diabetes induced the decrease of the ALT catalytic activities to 69.6% of control value. A similar level of decreased ALT catalytic activity was detected in the liver of control and diabetic mice fed with chow containing 0.1% acarbose. No changes in the specific and total activities of AST in the liver of the experimental groups were observed.Svrha ovog rada bila je ispitati kratkotrajni učinak 0.1% (m/m) akarboze u suhoj hrani na katalitičku koncentraciju specifičnih jetrenih enzima: alanin aminotransferaze (ALT) i aspartat aminotransferaze (AST) u jetri kontrolnih i dijabetičnih CBA miševa. Dijabetes je bio izazvan i.v. injekcijom aloksan-monohidrata u dozi od 75 mg kg -1 tjelesne mase miša sedam dana prije početka ishrane s akarbozom. U pokusu su ispitane četiri skupine CBA miševa: kontrolna (C) (n = 6) i dijabetična (D) (n = 8) skupina bile su sedam dana na standardnoj ishrani, te kontrolna (C / A – 100) (n = 8) i dijabetična (D / A-100) (n = 8) skupina koje su hranjene 0.1 % akarbozom umiješanom u standardnu hranu. U skupini D katalitička koncentracija ALT-a bila je značajno snižena u usporedbi s kontrolnom skupinom C. Sličan pad katalitičke koncentracije ALT-a zabilježen je i u jetri kontrolnih i dijabetičnih miševa hranjenih suhom hranom u koju je bila umiješana akarboza (0.1%). U ispitanim skupinama nisu zabilježene promjene u specifičnoj i ukupnoj aktivnosti AST-a

Ukupna taložna tvar na području Primorsko-goranske županije u razdoblju 1975.-2008.

Dustfall measurements in Primorsko-goranska county started in 1975 in the Bakar Bay (Site 2 - Bakar and Site 3 - Kraljevica). The measurements were extended to the city of Rijeka (Site 1 - Rijeka) in 1982, to the nearby islands (Site 4 - Krk and Site 5 - Cres) in 1986, and inland to Gorski Kotar (Site 6 - Delnice and Site 7 - Lividraga) in 1995. This article brings the results of dustfall measurements from 1975 to 2008. Dustfall was low in the city, the nearby islands, and Gorski Kotar. Recommended and limit values were occasionally exceeded in the Bakar Bay due to emissions from the coke plant and harbour at Site 2 (1979-1997) and from the shipyard at Site 3. Lead content in the dustfall was below the national limits, save for two occasions at Site 2. Deposition of sulphur and nitrogen at the inland sites were below the respective critical load values.Ispitivanja ukupne taložne tvari u Primorsko-goranskoj županiji započela su 1975. godine na području Bakarskog zaljeva. Mjerenja su se 1982. god proširila na grad Rijeku, 1986. na otoke Krk i Cres, a 1995. i na područje Gorskog kotara. U radu su prikazani rezultati mjerenja ukupne taložne tvari u razdoblju 1975.-2008. na sedam odabranih postaja: u gradu Rijeci, dvije na području Bakarskog zaljeva (Bakar i Kraljevica), dvije na otocima (Krk i Cres) te dvije u Gorskom kotaru (Delnice i Lividraga). Analizirano je kretanje prosječnih godišnjih vrijednosti ukupno istaloženih tvari te u njima prisutnih količina sagorivog pepela, sulfata, nitrata, amonija i olova. Na području grada Rijeke, otoka Krka i Cresa te Gorskog kotara količina ukupne taložne tvari je niska. Količine ukupne taložne tvari povremeno su prelazile preporučenu graničnu vrijednost u Bakru (1979.-1994.), zbog emisija iz koksare i iz luke za rasuti teret te u Kraljevici, gdje se osamdesetih godina osjećao utjecaj koksare u Bakru, a od sredine devedesetih pojačani rad u brodogradilištu. Količine olova u taložnoj tvari su niske na svim postajama, osim povremenih skokova u Bakru, kada su prijeđene preporučene vrijednosti. Količine istaloženog sumpora i dušika na području Gorskog kotara ispod su odgovarajućih vrijednosti kritičnog opterećenja za ispitivana područja

Simultaneous Extrema in the Entropy Production for Steady-State Fluid Flow in Parallel Pipes

Steady-state flow of an incompressible fluid in parallel pipes can simultaneously satisfy two contradictory extremum principles in the entropy production, depending on the flow conditions. For a constant total flow rate, the flow can satisfy (i) a pipe network minimum entropy production (MinEP) principle with respect to the flow rates, and (ii) the maximum entropy production (MaxEP) principle of Ziegler and Paltridge with respect to the choice of flow regime. The first principle - different to but allied to that of Prigogine - arises from the stability of the steady state compared to non-steady-state flows; it is proven for isothermal laminar and turbulent flows in parallel pipes with a constant power law exponent, but is otherwise invalid. The second principle appears to be more fundamental, driving the formation of turbulent flow in single and parallel pipes at higher Reynolds numbers. For constant head conditions, the flow can satisfy (i) a modified maximum entropy production (MaxEPMod) principle of \v{Z}upanovi\'c and co-workers with respect to the flow rates, and (ii) an inversion of the Ziegler-Paltridge MaxEP principle with respect to the flow regime. The interplay between these principles is demonstrated by examples.Comment: Revised version 2; 5 figure

T-cell subpopulations αβ and γδ in cord blood of very preterm infants : The influence of intrauterine infection

Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPreterm infants are very susceptible to infections. Immune response mechanisms in this group of patients and factors that influence cord blood mononuclear cell populations remain poorly understood and are considered insufficient. However, competent immune functions of the cord blood mononuclear cells are also described. The aim of this work was to evaluate the T-cell population (CD3+) with its subpopulations bearing T-cell receptor (TCR) αβ or TCR γδ in the cord blood of preterm infants born before 32 weeks of gestation by mothers with or without an intrauterine infection. Being a pilot study, it also aimed at feasibility check and assessment of an expected effect size. The cord blood samples of 46 infants age were subjected to direct immunofluorescent staining with monoclonal antibodies and then analyzed by flow cytometry. The percentage of CD3+ cells in neonates born by mothers with diagnosis of intrauterine infection was significantly lower than in neonates born by mothers without infection (p = 0.005; Mann-Whitney U test). The number of cells did not differ between groups. Infection present in the mother did not have an influence on the TCR αβ or TCR γδ subpopulations. Our study contributes to a better understanding of preterm infants' immune mechanisms, and sets the stage for further investigations.Peer reviewedFinal Published versio

Seroprevalence and entomological study on Chikungunya virus at the Croatian littoral

During 2011–2012, a total of 1008 serum samples from randomly selected inhabitants of seven Croatian counties located on the Adriatic Coast were tested for the presence of chikungunya virus (CHIKV) IgG antibodies using indirect immunofluorescence assay. Nine participants (0.9%) from four counties were found to be seropositive to CHIKV. Seroprevalence varied from 0.5% to 1.8% between counties. Additionally, a total of 3,699 mosquitoes were captured in 126 localities from August 16 to September 24, 2011. Three mosquito species were found: Ae. albopictus (3010/81.4%), Cx. pipiens (688/18.6%) and only one specimen of the Cs. longiareolata. Female mosquitoes (N = 1,748) were pooled. All pools tested negative for CHIKV RNA using a real-time RT-PCR

Estudio de la expresión génica en cultivos celulares de músculo esquelético estimulados por despolarización

El ejercicio y la estimulación eléctrica, que involucra despolarización de membrana, conducen a una adaptación funcional del músculo esquelético. El proceso adaptativo incluye hipertrofia y activación de mecanismos oxidativos, los que van acompañados de un incremento en la expresión génica, que se traduce en la síntesis de proteínas musculares específicas. Sin embargo, los mecanismos moleculares asociados a estas respuestas adaptativas aún no están totalmente dilucidados. Trabajos previos de nuestro laboratorio han demostrado que al despolarizar miotubos de músculo esquelético de rata y miotubos de la línea celular de ratón C2C12 ya sea con una elevada concentración de K+ o mediante estimulación eléctrica, estos responden con un aumento bifásico en la concentración de Ca+2 intracelular. El primer aumento o señal rápida de Ca+2 se localiza en el citoplasma y sería responsable del proceso contráctil. El segundo aumento o señal lenta de Ca+2 se asocia a los núcleos. La señal lenta de Ca+2 intracelular se genera a través de la liberación de Ca+2 por canales que responden a IP3 (IP3R). Estudios realizados en miotubos de la línea celular C2C12 sometidos a despolarización, indican que al utilizar agentes que inhiben la vía de inositol-1,4,5 trisfosfato (IP3) por distintos mecanismos, tales como 2-aminoetoxidifenil borato (2-APB), xestospongina C y U73122, la señal lenta de Ca+2 intracelular es inhibida completamente, sin afectar la señal rápida. El significado fisiológico de la señal lenta de Ca+2 se desconoce, pero se postula que estaría involucrada en la activación de factores transcripcionales y en la consecuente regulación de la expresión génica. En este sentido, nuestro laboratorio ha señalado que la despolarización de células de músculo esquelético produce un aumento transitorio en la expresión de los genes tempranos c-fos, c-jun y egr-1, en la que participa la señal lenta de Ca+2. Hasta la fecha se han realizado pocos estudios que describan los cambios en la expresión génica en respuesta a la despolarización en células musculares, y ningún estudio que relacione la señal lenta de Ca+2 intracelular con la expresión de genes específicos del músculo esquelético. Nuestro trabajo inicial se centró en el estudio de la expresión del gen que codifica para Interleuquina-6 (IL-6), basándonos en antecedentes de la literatura que describen que el ejercicio produce un incremento en la concentración plasmática de esta citoquina. Además, el gen de IL-6 posee en su promotor varias secuencias de consenso que pueden ser moduladas por Ca+2. Mediante RT-PCR demostramos que la despolarización con K+ 84mM de miotubos de rata y de células C2C12, aumenta el nivel de mRNA de IL-6 con una inducción máxima de 3,5 veces entre 3 y 4 hrs, efecto que no depende del Ca+2 extracelular. El tratamiento de las células con BAPTA-AM, quelante intracelular de Ca+2 o con inhibidores de la señal lenta de Ca+2, tales como 2APB, xestospongina C y U73122, disminuyen la inducción de IL-6 en células despolarizadas. Al despolarizar miotubos transfectados con un gen reportero de luciferasa que contiene un fragmento de 651 bp del promotor de IL-6, se observó un aumento de 2 veces en la actividad del promotor en relación a miotubos no estimulados. Este aumento persiste en miotubos tratados con rianodina 25μM, pero disminuye significativamente en presencia de 2-APB y U73122. Mutaciones en los sitios NF-κB y AP-1, presentes en el promotor de IL-6, disminuyen la expresión del gen reportero inducida por K+. En conjunto, estos resultados sugieren la participación de la señal lenta de Ca+2 en la activación transcripcional de IL-6 en miotubos despolarizados con K+, y de NF-κB y AP-1 como elementos regulatorios. Para identificar otros genes que se expresan diferencialmente en respuesta a la despolarización, se realizaron experimentos mediante la técnica de Microarrays de oligonucleótidos (Compugen 22K, 21.920 genes), utilizando el RNA total de miotubos de células C2C12 despolarizados con K+ 84 mM por 5 min, recolectado entre las 2 a 24 horas post-estímulo. De los análisis mediante la base de datos del NCI-CIT, identificamos un total de 127 genes que presentan un aumento o disminución de su expresión de al menos 1,7 veces con respecto al control sin estímulo, en el transcurso del período de 24 h. Se observaron cambios significativos en genes involucrados en respuesta a estrés, metabolismo y comunicación celular, entre otros. Dentro de los genes que se expresan diferencialmente por efecto de la despolarización, figuran el de α-actina esquelética (Acta1) y el de troponina I (Tnni), que codifican proteínas estructurales de músculo. El análisis por microarrays indica que ambos genes presentan su máxima inducción a las 4 horas después de la despolarización, lo que se confirmó mediante RT-PCR. La despolarización con K+ 84mM de miotubos de rata y miotubos de células C2C12 produce un aumento en el nivel de mRNA de 1,5 veces para Tnni y 2 veces para Acta1. El pre-tratamiento de los miotubos con 2-APB o U73122 no afecta la inducción en la expresión de Acta1, pero si disminuye la de Tnni, lo que sugiere la participación de la señal lenta de Ca+2 en la regulación de la expresión génica de Tnni, pero no de Acta1. La importancia de este estudio es que constituye el primer trabajo que demuestra directamente la participación de las señales de Ca+2 intracelular, mediadas por IP3R, como factor de señalización de vías que llevan a la expresión de genes tardíos específicos, tales como IL-6 y Tnni, en células de músculo esquelético sometidas a despolarización. Además, esta tesis destaca porque se encontró un modelo que se presta muy bien para el estudio de la expresión génica mediante la técnica de Microarrays, que permite estudiar efectivamente la relación entre los cambios de potencial y la expresión génica en células de músculo esquelético. Las células musculares con sólo un cambio de potencial de membrana como estímulo, muestran cambios consistentes en una cantidad limitada de genes, lo que permitirá estudiar los mecanismos involucrados en su regulación.FONDAP 15010006; Proyecto de colaboración internacional. Laboratory of Molecular Technology, National Cancer Institute at Frederick, EEUU. SAIC-Frederick, Inc.; CONICYT AT- 403115Versión original del auto

design of selective peptide antibiotics by using the sequence moment concept

New antibiotics against multidrug-resistant bacteria are urgently needed, but rapid acquisition of resistance limits their usefulness. Endogenous antimicrobial peptides (AMPs) with moderate selectivity, but multimodal mechanism of action, have remained effective against bacteria for millions of years. Their therapeutic application, however, requires optimizing the balance between antibacterial activity and selectivity, so that rational design methods for increasing selectivity are highly desirable. We have created training (n=36) and testing (n=37) sets from frog-derived AMPs with determined therapeutic index (TI). The 'sequence moments' concept then enabled us to find a one-parameter linear model resulting in a good correlation between measured and predicted TI (r2=0.83 and 0.64 for each set, respectively). The concept was then used in the AMP-Designer algorithm to propose primary structures for highly selective AMPs against Gram-negative bacteria. Testing the activity of one such peptide produced a TI>200 as compared to the best AMP in the data-base, with TI=125

Mechanistic and evolutionary questions about epigenetic conflicts between transposable elements and their plant hosts

Transposable elements (TEs) constitute the majority of plant genomes, but most are epigenetically inactivated by their host. Research over the last decade has elucidated many of the molecular components that are required for TE silencing. In contrast, the evolutionary dynamics between TEs and silencing pathways are less clear. Here, we discuss current information about these dynamics from both mechanistic and evolutionary perspectives. We highlight new evidence that palindromic sequences within TEs may act as signals for host recognition and that cis-regulatory regions of TEs may be sites of ongoing arms races with host defenses. We also discuss patterns of TE aging after they are silenced; while there is not yet a consensus, it appears that TEs are removed more rapidly near genes, such that older TE insertions tend to be farther from genes. We conclude by discussing the energetic costs for maintaining silencing pathways, which appear to be substantive. The maintenance of silencing pathways across many species suggests that epigenetic emergencies are frequent

Voltage-gated Na⁺ channel activity increases colon cancertranscriptional activity and invasion via persistent MAPK signaling

© 2015 Macmillan Publishers Limited. All rights reserved. Functional expression of voltage-gated Na+ channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using pharmacological inhibitors/activators and siRNA-mediated gene knockdowns, we correlated channel activity with Rap1-dependent persistent MAPK activation in the SW620 human colon cancer cell line. We further demonstrated that VGSC activity induces downstream changes in invasion-related gene expression via a PKA/ERK/c-JUN/ELK-1/ETS-1 transcriptional pathway. This is the first study illustrating a molecular mechanism linking functional activity of VGSCs to transcriptional activation of invasion-related genes