Search results for "lamprey"

Selection of spawning substratum by European river lampreys (Lampetra fluviatilis) in experimental tanks

2014

The selection of spawning substratum by the river lamprey (Lampetra fluviatilis) was studied in two experimental tanks with different flow conditions. In both tanks, four gravel sizes mixed with 15% sand were available to the test animals. In the tank with the lower current speed, lampreys selected in favour of the finest (2–8 mm) gravel size available against gravel sizes 4–20 mm and 8–40 mm. Selection was also significantly different in the tank with higher current speed where selection against the medium-sized substratum (4–20 mm) was evident, but there were no differences between selection for gravel sizes 2–8 mm, 2–40 mm and 8–40 mm relative to availability. Substratum selection and ob…

The Globin Gene Repertoire of Lampreys: Convergent Evolution of Hemoglobin and Myoglobin in Jawed and Jawless Vertebrates

2014

Agnathans (jawless vertebrates) occupy a key phylogenetic position for illuminating the evolution of vertebrate anatomy and physiology. Evaluation of the agnathan globin gene repertoire can thus aid efforts to reconstruct the origin and evolution of the globin genes of vertebrates, a superfamily that includes the well-known model proteins hemoglobin and myoglobin. Here, we report a comprehensive analysis of the genome of the sea lamprey (Petromyzon marinus )w hich revealed 23 intact globin genes and two hemoglobin pseudogenes. Analyses of the genome of the Arctic lamprey (Lethenteron camtschaticum) identified 18 full length and five partial globin gene sequences. The majority of the globin …

Evolution of tissue-specific keratins as deduced from novel cDNA sequences of the lungfish Protopterus aethiopicus.

2005

Lungfishes are possibly the closest extant relatives of the land vertebrates (tetrapods). We report here the cDNA and predicted amino acid sequences of 13 different keratins (ten type I and three type II) of the lungfish Protopterus aethiopicus. These keratins include the orthologs of human K8 and K18. The lungfish keratins were also identified in tissue extracts using two-dimensional polyacrylamide gel electrophoresis, keratin blot binding assays and immunoblotting. The identified keratin spots were analyzed by peptide mass fingerprinting which assigned seven sequences (inclusively Protopterus K8 and K18) to their respective protein spot. The peptide mass fingerprints also revealed the fac…

Lotic life stages of the European river lamprey (Lampetra fluviatilis) : anthropogenic detriment and rehabilitation

2015

Latvijas Vēstures Institūta Žurnāls. 2018, Nr. 2 (107) 

2018

Žurnāls sagatavots LU Akadēmiskās attīstības projekta “Zinātniskā periodiskā izdevuma “Latvijas Vēstures Institūta Žurnāls” sagatavošana un izdošana 2018. gadā” (vad. Guntis Zemītis) ietvaros

Functional characterization of two melanocortin (MC) receptors in lamprey showing orthology to the MC1 and MC4 receptor subtypes

2007

Abstract Background The melanocortin (MC) receptors have a key role in regulating body weight and pigmentation. They belong to the rhodopsin family of G protein-coupled receptors (GPCRs). The purpose of this study was to identify ancestral MC receptors in agnathan, river lamprey. Results We report cloning of two MC receptors from river lamprey. The lamprey receptors, designated MCa and MCb, showed orthology to the MC1 and MC4 receptor subtypes, respectively. The molecular clock analysis suggested that lamprey MC receptor genes were not duplicated recently and diverged from each other more than 400 MYR ago. Expression and pharmacological characterization showed that the lamprey MCa receptor …

Upes nēģa Lampetra fluviatilis populāciju ģenētiskās daudzveidības izpēte ar mikrosatelītiem

2020

Šis bakalaura darbs ir turpinājums kursa darbam - “Kurzemes upēs sastopamo upes nēģu Lampetra fluviatilis mikrosatelītu genotipēšana”. Šis ir pirmais pētījums Latvijā par upes nēģa ģenētisko daudzveidību un populācijas ģenētisko struktūru Latvijas upēs, pamatojoties uz mikrosatelītu DNS variācijām. Darba mērķis bija novērtēt upes nēģa populācijas ģenētisko daudzveidību Latvijā. Iegūtie dati veicinās zināšanas par upes nēģu ģenētisko struktūru un palīdzēs izstrādāt ieteikumus ģenētisko resursu ilgtspējīgai apsaimniekošanai. No piecām upēm (Saka, Venta, Daugava, Salaca, Gauja) kopā tika ievākti 210 upes nēģa audu paraugi no muguras spurām, no kuriem tika izdalīta DNS. Genotipēšana tika veikta…

Eudontomyzon danfordi (Regan, 1911) Species Populations Ecological Status in Maramureş Mountains Nature Park (Romania)

2015

Abstract The Eudontomyzon danfordi characteristic habitats state of Maramureş Mountains Nature Park varies greatly, 19.05% are in excellent conservation status, 47.62% are in good/average status and 33.33% are in a partially degraded condition. The identified human impact categories which induced the decreasing of Eudontomyzon danfordi species habitat state in the studied area are: poaching, minor riverbeds morphodynamic changings, liquid and solid natural flow disruption, destruction of riparian trees and bush vegetation, habitat fragmentation-fish populations isolation, and organic/mining pollution activities.

Genes coding for intermediate filament proteins closely related to the hagfish "thread keratins (TK)" alpha and gamma also exist in lamprey, teleosts…

2005

The "thread keratins (TK)" alpha and gamma so far have been considered highly specialized intermediate filament (IF) proteins restricted to hagfish. From lamprey, we now have sequenced five novel IF proteins closely related to TKalpha and TKgamma, respectively. Moreover, we have detected corresponding sequences in EST and genomic databases of teleosts and amphibians. The structure of the TKalpha genes and the positions of their deduced amino acid sequences in a phylogenetic tree clearly support their classification as type II keratins. The genes encoding TKgamma show a structure typical for type III IF proteins, whereas their positions in phylogenetic trees favor a close relationship to the…

Migratory behaviour and holding habitats of adult river lampreys (Lampetra fluviatilis) in two Finnish rivers

2015

The effect of environmental factors on migratory activity of adult river lampreys entering the Kalajoki and Perhonjoki, rivers in Finland, for spawning was studied using correlation and regression analyses. Telemetric tracking of 60 individuals was utilized to study the migratory patterns and holding habitat requirements of adult river lampreys. The increases in the river discharge, wind forcing towards the river mouth and speed and magnitude of river water cooling had positive effects on the numbers of lampreys entering the rivers whereas the increase in the illumination intensity of the moon had a negative effect on their migration activity. Radio-tagged lampreys typically passed slow-flo…