Ecological properties of the hybridogenetic green frog complex (Pelophylax esculentus complex; Ranidae, Anura) from the northwestern area of Croatia

Na području Bjelovarsko-Bilogorske županije, u razdoblju od 02.05. do 06.05.2007. godine uhvaćene su jedinke zelenih žaba (Pelophylax esculentus kompleksa). Uzorak od 84 jedinke korišten je za izolaciju sadržaja želudca i bedrene kosti. Cilj istraživanja bio je odrediti sastav prehrane i procijeniti dob jedinki pojedine vrste P. esculentus kompleksa. Željela se utvrditi dob postizanja spolne zrelosti jedinki pojedine vrste. Određivanje sastava prehrane uključivalo je izolaciju i determinaciju ostataka plijena dok se za procjenu dobne strukture uzorka koristila metoda skeletokronologije. Rezultati istraživanja pokazali su da jedinke proučavanog kompleksa svoju prehranu temelje na plijenu iz razreda Insecta. Najmlađe jedinke (dvije godine) pripadaju vrstama P. kl. esculentus i P. lessonae dok najstarija jedinka (13 godina) pripada vrsti P. ridibundus. Utvrđeno je da spolna zrelost jedinki P. kl. esculentus i P. lessonae vrste nastupa u dobi od 3 do 4 godine života. Ovim radom istaknute su razlike između vrsta P. esculentus kompleksa unutar promatranog uzroka.We studied 84 specimen of the green frog complex (Pelophylax esculentus complex) caught in the area of Bjelovarsko-Bilogorska county, in the period from May 2nd until May 6th 2007. We isolated the stomach content and one femural bone from each individual. The purpose of the study was to determine the content of the diet and to do the age analysis of each species within the P. esculentus complex. Also, we wanted to determine the age at maturity for each P. esculentus complex species. Results showed that all three species base their diet on the prey from the class Insecta. The youngest individuals (two years) belong to the P. kl. esculentus and P. lessonae species while the oldest individual (13 years) belongs to the P. ridibundus species. The latter species reach sexual maturity by the age of 3 to 4 years. This study highlights the differences among P. esculentus complex species

Effect of sex hormones on the expression of chloride/formate exchanger (Cfex, Slc26a6) in rat organs

Izmjenjivač klora i mravlje kiseline (Cfex/Slc26a6) je transmembranski protein koji prenosi ione klora, bikarbonata, oksalata, mravlje kiseline i hidroksilne ione u sisavaca. Dosadašnja istraživanja pretpostavljaju ulogu tog proteina u nastanku oksalatnih kamenaca u urinarnom traktu, s većom učestalošću u muškaraca. Zbog slabe istraženosti u štakora, kao učestalo rabljenih pokusnih životinja, njegova lokalizacija i moguća spolno-ovisna ekspresija istražena je u različitim tkivima/organima štakora. Specifičnost anti-CFEX protutijela utvrđena je heterolognim ekspresijskim sustavom u kojemu su stanice HEK293 transfecirane cjelovitom cDNA za rCfex. Metodom RT-PCR, ekspresija mRNA za rCfex utvrđena je u tankom crijevu, bubrezima, jetri i gušterači. Imunofluorescencijskom analizom protein rCfex je lokaliziran u četkastim membranama enterocita i proksimalnih kanalića bubrega, kanalikularnim membranama hepatocita i izvodnim kanalićima gušterače. U bubrezima je kastracija smanjivala, a testosteron povećavao njegovu ekspresiju. Dakle, mRNA/protein rCfex je prisutan u različitim tkivima/organima štakora, dok je u bubrezima njegova ekspresija dominantna u mužjaka uslijed stimulacijskog učinka androgena nakon puberteta.The chloride/formate exchanger (Cfex/Slc26a6) is a transmembrane protein mediating chloride, bicarbonate, oxalate, formate and hydroxyl ions transport in mammals. Previous findings support its possible role in the oxalate urinary tract stones formation, with higher incidence in men. Due to lack of data in rats, as commonly used experimental animals, its cell localization and possible sex-related expression was investigated in various rat organs/tissues. Specificity of anti-CFEX antibody was verified by heterologous expression systems using a full-length rCfex cDNA-transfected HEK293 cells. By RT-PCR, rCfex mRNA was detected in the kidneys, liver, pancreas and small intestine. By immunofluorescence, protein rCfex was localized in the apical membrane of enterocytes and renal proximal tubules, hepatocyte canalicular membranes, and luminal domain of pancreatic ducts. Its renal expression was downregulated by castration, and upregulated by testosteron. Therefore, the rCfex mRNA/protein is expressed in various rat organs/tissues, whereas its renal expression is maledominant due to post-pubertal androgen stimulation

Prijenosnici natrija i glukoze: nove mete ciljanih terapija u liječenju raka?

Glucose, the key source of metabolic energy, is imported into cells by two categories of transporters: 1) facilitative glucose transporters (GLUTs) and 2) secondary active sodium-glucose cotransporters (SGLTs). Cancer cells have an increased demand for glucose uptake and utilisation compared to normal cells. Previous studies have demonstrated the overexpression of GLUTs, mainly GLUT1, in many cancer types. As the current standard positron emission tomography (PET) tracer 2-deoxy-2-(18F)fluoro-D-glucose (2-FDG) for imaging tumour cells via GLUT1 lacks in sensitivity and specificity, it may soon be replaced by the newly designed, highly sensitive and specific SGLT tracer α-methyl-4-(F-18)fluoro-4-deoxy-Dglucopyranoside (Me-4FDG) in clinical detection and tumour staging. This tracer has recently demonstrated the functional activity of SGLT in pancreatic, prostate, and brain cancers. The mRNA and protein expression of SGLTs have also been reported in colon/colorectal, lung, ovarian, head, neck, and oral squamous carcinomas. So far, SGLTs have been poorly investigated in cancer, and their protein expression and localisation are often controversial due to a lack of specific SGLT antibodies. In this review, we describe current knowledge concerning SGLT1 and SGLT2 (over)expression in various cancer types. The findings of SGLTs in malignant cells may help in developing novel cancer therapies with SGLT2 or SGLT1/SGLT2 inhibitors already used in diabetes mellitus treatment.Glukoza, glavni izvor metaboličke energije, ulazi u stanicu na dva načina: 1) olakšanom difuzijom pomoću prijenosnika glukoze GLUT i 2) sekundarno aktivnim prijenosom pomoću prijenosnika natrija i glukoze SGLT. Stanice raka imaju povećani unos glukoze u usporedbi s normalnim stanicama. Prethodna istraživanja pokazala su povećanu ekspresiju prijenosnika GLUT, uglavnom GLUT1, u mnogim tipovima raka. Radiofarmaceutik (engl. tracer) 2-deoksi-2-(18F) fluoro-D-glukoza (2-FDG), koji se koristi za detekciju tumorskih stanica putem GLUT1, nije dovoljno osjetljiv i specifičan. Uskoro bi mogao biti zamijenjen α-metil-4-(F-18) fluoro-4-deoksi-D-glukopiranozidom (Me-4FDG), novim i visoko osjetljivim, i specifičnim SGLT-radiofarmaceutikom u kliničkoj detekciji i određivanju stadija tumora. Tim je radiofarmaceutikom nedavno dokazana funkcionalna aktivnost prijenosnika SGLT u raku gušterače, prostate i mozga. Ekspresija mRNA i proteina SGLT također je pronađena u raku debelog crijeva, pluća, jajnika, glave, vrata i pločastih stanica usne šupljine. Prijenosnici SGLT nedovoljno su istraženi u raku, a njihova ekspresija i lokalizacija često su oprečne zbog nedostatka specifičnih SGLT-protutijela. U ovom preglednom radu opisujemo trenutačna znanja o povećanoj ekspresiji prijenosnika SGLT1 i SGLT2 u različitim tipovima raka. Spoznaje o ekspresiji i/ili lokalizaciji prijenosnika SGLT u malignim stanicama pomoći će u razvoju novih terapija u liječenju raka korištenjem već poznatih antidijabetika, SGLT2 ili SGLT1/SGLT2 inhibitora

In female rats, ethylene glycol treatment elevates protein expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) without inducing hyperoxaluria

Aim To investigate whether the sex-dependent expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) changes in a rat model of ethylene glycol (EG)-induced hyperoxaluria. Methods Rats were given tap water (12 males and 12 females; controls) or EG (12 males and 12 females; 0.75% v/v in tap water) for one month. Oxaluric state was confirmed by biochemical parameters in blood plasma, urine, and tissues. Expression of sat-1 and rate-limiting enzymes of oxalate synthesis, alcohol dehydrogenase 1 (Adh1) and hydroxy-acid oxidase 1 (Hao1), was determined by immunocytochemistry (protein) and/or real time reverse transcription polymerase chain reaction (mRNA). Results EG-treated males had significantly higher (in μmol/L; mean ± standard deviation) plasma (59.7 ± 27.2 vs 12.9 ± 4.1, P < 0.001) and urine (3716 ± 1726 vs 241 ± 204, P < 0.001) oxalate levels, and more abundant oxalate crystaluria than controls, while the liver and kidney sat-1 protein and mRNA expression did not differ significantly between these groups. EG-treated females, in comparison with controls had significantly higher (in μmol/L) serum oxalate levels (18.8 ± 2.9 vs 11.6 ± 4.9, P < 0.001), unchanged urine oxalate levels, low oxalate crystaluria, and significantly higher expression (in relative fluorescence units) of the liver (1.59 ± 0.61 vs 0.56 ± 0.39, P = 0.006) and kidney (1.77 ± 0.42 vs 0.69 ± 0.27, P < 0.001) sat-1 protein, but not mRNA. The mRNA expression of Adh1 was femaledominant and that of Hao1 male-dominant, but both were unaffected by EG treatment. Conclusions An increased expression of hepatic and renal oxalate transporting protein sat-1 in EG-treated female rats could protect from hyperoxaluria and oxalate urolithiasis

Spolno-neovisna ekspresija izmjenjivača klora i mravlje kiseline Cfex (Slc26a6) u gušterači, tankom crijevu i jetri štakora i povišena ekspresija u bubrezima mužjaka

Chloride/formate exchanger (CFEX; SLC26A6) mediates oxalate transport in various mammalian organs. Studies in Cfex knockout mice indicated its possible role in development of male-dominant hyperoxaluria and oxalate urolithiasis. Rats provide an important model for studying this pathophysiological condition, but data on Cfex (rCfex) localisation and regulation in their organs are limited. Here we applied the RT-PCR and immunochemical methods to investigate rCfex mRNA and protein expression and regulation by sex hormones in the pancreas, small intestine, liver, and kidneys from intact prepubertal and adult as well as gonadectomised adult rats treated with sex hormones. rCfex cDNA-transfected HEK293 cells were used to confirm the specificity of the commercial anti-CFEX antibody. Various biochemical parameters were measured in 24-h urine collected in metabolic cages. rCfex mRNA and related protein expression varied in all tested organs. Sex-independent expression of the rCfex protein was detected in pancreatic intercalated ducts (apical domain), small intestinal enterocytes (brush-border membrane; duodenum > jejunum > ileum), and hepatocytes (canalicular membrane). In kidneys, the rCfex protein was immunolocalised to the proximal tubule brush-border with segment-specific pattern (S1=S2 jejunum > ileum) i kanalikularnoj membrani hepatocita. U bubrezima je a) prijenosnik rCfex imunolokaliziran u četkastoj membrani proksimalnih kanalića sa segment-specifičnim obrascem (S1=S2 ženke) zbog stimulacijskoga učinka androgena nakon puberteta. Međutim, izlučivanje oksalata urinom nije bilo sukladno ekspresiji bubrežnoga prijenosnika rCfex. Dakle, nejasan je učinak povišene ekspresije prijenosnika rCfex u proksimalnim kanalićima mužjaka na izlučivanje oksalata, a postojanje prijenosnika u kanalikularnoj membrani hepatocita mogući je put izlučivanja oksalata putem žuči

Prilog poznavanju faune vodozemaca i gmazova donjeg dijela rijeke Une i njenog priobalnog pojasa

With this paper the authors wanted to gather more information about the presence of reptilian and amphibian species in the area of lower Una River and its surroundings. For this purpose field surveys in the form of active searching in promising places was conducted on four separate occasions in 2009. Here we present the list of 10 amphibian species (plus one klepton) and 7 reptile species recorded during the course of our study. 11 of these, all together 18 taxa, are in the strictly protected and 7 of them are in the protected category according to the Croatian Nature Protection Act.S ovim radom autori su željeli prikupiti više informacija o prisutnosti vodozemaca i gmazova na širem podruþju donjeg toka rijeke Une. U tu svrhu tokom 2009. godine provedena su iscrpna terenska istraživanja u obliku aktivnog pretraživanja terena na pogodnim staništima. Ovdje donosimo popis 10 vrsta vodozemaca (plus jedan “klepton”) i 7 vrsta gmazova zabilježenih tijekom našeg istraživanja. 11 od njih nalazi se u kategoriji strogo zaštiüenih, a sedam u kategoriji zaštiüenih svojti prema Zakonu o zaštiti prirode Republike Hrvatske

Comparative morphology and ecology of the Pelophylax esculentus complex in Croatia

The Eurasian Pelophylax esculentus hybridogenetic complex, including Pelophylax ridibundus (R), P. lessonae (L), and their hybrid P. kl. esculentus (E), is considered to be one of the most complicated animal hemiclonal systems. It has been attracting the attention of evolutionary and molecular biologists as well as ecologists for decades. Despite the considerable number of studies describing population structure, reproductive modes, and distribution of the species complex, data on the rarely observed REL scenario, i.e., the presence of all three species at one site, are lacking. This study compared the morphological (morphometry, external morphology) and ecological (diet) profiles of all three species from a REL complex population located in the northwestern part of Croatia (Bjelovarsko-Bilogorska County). In terms of external morphology, the species varied interspecifically, but some features, for example, the yellow or green femoral colouration found in P. ridibundus, had not been expected. All three species exhibited a strong predilection for terrestrial prey, but interspecific differences were noticed. This paper aims to provide a better and more comprehensible insight into the ecological relationships of the REL complex, allowing comparisons with other study areas across Europe

Comparative morphology and ecology of the Pelophylax esculentus complex in Croatia

The Eurasian Pelophylax esculentus hybridogenetic complex, including Pelophylax ridibundus (R), P. lessonae (L), and their hybrid P. kl. esculentus (E), is considered to be one of the most complicated animal hemiclonal systems. It has been attracting the attention of evolutionary and molecular biologists as well as ecologists for decades. Despite the considerable number of studies describing population structure, reproductive modes, and distribution of the species complex, data on the rarely observed REL scenario, i.e., the presence of all three species at one site, are lacking. This study compared the morphological (morphometry, external morphology) and ecological (diet) profiles of all three species from a REL complex population located in the northwestern part of Croatia (Bjelovarsko-Bilogorska County). In terms of external morphology, the species varied interspecifically, but some features, for example, the yellow or green femoral colouration found in P. ridibundus, had not been expected. All three species exhibited a strong predilection for terrestrial prey, but interspecific differences were noticed. This paper aims to provide a better and more comprehensible insight into the ecological relationships of the REL complex, allowing comparisons with other study areas across Europe

Composition and age structure of the Pelophylax esculentus complex (Anura ; Ranidae) population in inland Croatia

Pelophylax esculentus is a vertebrate animal with hemiclonal heredity, attracting the interest of many reproductive and evolutionary biologists. It is a hybrid between P. ridibundus and P. lessonae. These three taxa form the so-called Pelophylax esculentus complex with a population structure usually comprising a hybrid taxa and one parental species. Data on population types at the southernmost distribution area of their sympatry are rare. Here we sampled five sites in inland Croatia in order to analyse the population structure, sex ratio and age structure. The individual genotypes of 93 randomly collected water frogs were verified with allozyme markers for three species-specific polymorphic loci. In order to estimate population age structure, the annual growth rate (skeletochronology) and growth index profiles were also investigated. The growth index profiles were analysed by an estimation of number of lines of arrested growth visible in the cross-section of femur bones. Our results revealed the presence of the R-E-L population with a dominance of P. esculentus. Pelophylax ridibundus was the least abundant taxon but with a relatively high age estimate of eight years on average. Its annual growth rate did not differ from the remaining two species. Gene introgression of mostly ridibundus alleles was also observed in hybrids. Most profiles of gonads in hybrids showed presence of both parental genomes with dominance of ridibundus alleles. The study area represents one of the southernmost distributions of the hybrid taxon in Europe, making it attractive to study gene flow and impact of P. esculentus on P. ridibundus, a typical water frog representative of the Balkan Peninsula