811 research outputs found
Not more than three tissue kallikreins identified from organs of the guinea pig
The large and varied multigene families of tissue kallikreins of rat and mouse are considered to selectively release as many bioactive peptides. In order to determine whether a similar family of enzymes is expressed in the organs of the guinea pig purification studies were performed. Tissue kallikreins from the submandibular gland, coagulating gland/prostate complex and the pancreas were separated by affinity chromatography on benzamidine-Sepharose. Amino-terminal sequences, the patterns of hydrolysis rates of a number of peptide p-nitroanilides, inactivation rates by active site-directed irreversible inhibitors, specific kininogenase activities and types of kinin released were used to probe the identity of the isolated enzymes. Guinea pig tissue kallikreins 1 and 2 have been reported previously. In the present study we have identified a third type, designated tissue kallikrein la because of its sequence similarity to kallikrein 1, which differs from the latter in the catalytic properties. The inferred occurrence of not more than two or three independent tissue kallikrein genes in the guinea pig contrasts with the varied family of enzymes expressed by the large number of such genes present in rats and mice. Expression in the guinea pig (and also in humans) of only a small number of tissue kallikreins makes specific processing of a multitude of biologically active peptides by such enzymes unlikely
Opponent left-handedness does not affect fight outcomes for Ultimate Fighting Championship hall of famers
BACKGROUND
Concluding remarks:"Biobanking for cancer research: Rules and roles," november 2010, Bari, Italy
Voedselkeuzes en draagkracht: de mogelijke consequenties van veranderingen in de draagkracht van Nederlandse kustwateren op het voedsel van schelpdieretende wad- en watervogels
De Waddenzee en de Noordzeekustzone zijn aangewezen als Natura2000-gebieden. Naast een verplichting tot instandhouding is voor de Waddenzee een verbeterdoelstelling geformuleerd voor de schelpdieretende vogelsoorten Eider (als broedvogel en als niet-broedvogel), Topper, Kanoet, Scholekster en Steenloper (voor deze soorten als niet-broedvogel). Voor de Noordzeekustzone zijn voor schelpdieretende kustvogels en voor de aangewezen habitattypen alleen behoudsdoelstellingen geformuleerd. Anno 2010 voldoen de populaties van de Topper, de Kanoet en de Steenloper aan de Instandhoudingsdoelstellingen voor de Waddenzee. De aantallen van de Eider en de Scholekster liggen lager dan de geformuleerde doelstellingen. In de Noordzeekustzone liggen de aantallen Zwarte Zee-eenden, Eiders en Scholeksters onder de geformuleerde Instandhoudingsdoelstellingen. Voor de Kanoet werden deze gehaald tussen 1999-2000 en 2003-2004 maar de actuele situatie is onduidelijk. Gedurende de laatste decennia waren verscheidene factoren van belang voor de aantalsontwikkeling van de meeste schelpdieretende vogelsoorten. Het toenmalige Ministerie van LNV (nu EL&I) heeft in 2008 aan IMARES vragen gesteld die in het kader van een zogenaamd BO-project moesten worden beantwoord. Voor de belangrijkste soorten schelpdieretende vogels (de hierboven genoemde soorten plus de Zwarte Zeeeend) gaat het om de volgende vragen: In hoeverre is het benodigde voedsel aanwezig? Is het beschikbare voedsel van voldoende kwaliteit? Is het preferente voedsel beschikbaar en bereikbaar? Krijgen de vogels voldoende gelegenheid om het voedsel ook te bemachtigen (onder invloed van ecologische en antropogene factoren)? Deze basisvragen zijn door het Ministerie voor de 6 te onderzoeken vogelsoorten (Eider, Zwarte Zeeeend, Toppereend, Scholekster, Kanoet en Steenloper) vertaald naar de in Hoofdstukken 3 t/m 8 weergegeven kennisvragen per soort. Deze richten zich vooral op de voedselecologie van de genoemde schelpdieretende soorten. De centrale vraag die in dit rapport wordt besproken is in hoeverre de condities binnen de Waddenzee en de Noordzeekustzone van invloed zijn of kunnen zijn op de populatieomvang van de genoemde soorten. De belangrijkste factoren die hierop invloed kunnen hebben zijn habitatgeschiktheid en voedselvoorziening. Habitatgeschiktheid is in deze gebieden vooral gekoppeld aan de aanwezigheid van geschikte leefgebieden en verstoring, voedselvoorziening aan de beschikbaarheid van voldoende hoeveelheden geschikte prooidieren
Prostate-specific antigen: gene structure and regulation of expression
As a start of our study of prostate-specific and androgen-dependent expression of PA,
various PA cDNAs (Chapter II) and the PA gene (Chapter Ill) were isolated and
characterized. The PA gene turned out to be a member of a small kaHikrein family,
encompassing two other closely related genes Ithe human Glandular Kal!ikrein-1 gene
(hGK-1), and the tissue kallikrein gene {KLK1)]. Genetic characterization of the human
kallikrein genes showed clustering in a 60 kb segment on chromosome 19q13.2-13.4
(Chapters IV and V). The hGK-1 gene shows a strong homology to PA and is, similarly
to PA, exclusively expressed in prostate tissue. KLK1 is mainly expressed in kidney,
pancreas and salivary glands.
In addition to PA eDNA, hGK-1 cDNAs were isolated and characterized. This allowed
the comparison of PA and hGK-1 mRNA expression. Using hGK-1 and ?A-specific
eDNA probes, androgen-stimulated mRNA expression of PA and hGK-1 could be
determined (Chapter VI). Further, an androgen responsive element in the promoter
region of the PA gene was defined and tested for its functional activity (Chapter Vl!).
The homology of the PA, hGK-1 and KLK1 genes does not only include the open
reading frame, but extends into the promoter regions, although the genes are at least
partially expressed in different tissues and at different levels. The above mentioned
aspects, resulted in the development of a model system for the study of tissue-specific
and hormone-responsive gene expression in the human prostate
Schatting van de primaire productie in de Waddenzee in de laatste drie decennia
In dit rapport wordt een schatting gepresenteerd van de primaire productie in de oostelijke en de westelijke Waddenzee gedurende de laatste drie decennia. Deze gegevens worden in een ander onderdeel van het project Meerjarige effect- en productiemetingen aan MZI's in de Westelijke Waddenzee en Oosterschelde gebruikt voor het valideren van een model dat het effect berekend van opschaling van MZI’s (mosselzaadinvangsystemen) op de draagkracht voor schelpdieren in de Waddenzee
Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments
Laboratory experiments were carried out to investigate the effect of protozoan, copepod and combined grazing on Phaeocystis biomass. Phaeocystis cf. globosa single cells were offered to 3 different protozoan species, to the calanoid copepod Temora longicornis, as well as to mixtures of both grazer types. The heterotrophic dinoflagellate Oxyrrhis marina and the oligotrich ciliate Strombidinopsis acuminatum ingested Phaeocystis at much higher rates than did the copepod. Nevertheless, protozoan growth and ingestion rates were submaximal, indicating Phaeocystis to be suboptimal food.
The oligotrich ciliate Strombidium elegans did not feed on Phaeocystis. In grazing experiments with mixtures of both predator types, the decline of Phaeocystis single cells could be explained by protozoan grazing alone, implying no grazing by the copepods on Phaeocystis. Instead, copepods ingested the protozoans at high rates. Predation on 0. marina and S. acuminatum by T. longicornis resulted in a
reduction of the total grazing pressure on Phaeocystis of 21 and 67 % respectively. We conclude that mesozooplankton predation on herbivorous ciliates and heterotrophic dinoflagellates, which consumed Phaeocystis cells, can considerably reduce the overall grazing pressure and may enhance Phaeocystis
bloomng
How standardization of the pre-analytical phase of both research and diagnostic biomaterials can increase reproducibility of biomedical research and diagnostics.
Comparison of published biomedical studies shows that a large proportion are irreproducible, causing severe damage to society and creating an image of wasted investments. These observations are of course damaging to the biomedical research field, which is currently full of future promise. Precision medicine and disease prevention are successful, but are progressing slowly due to irreproducible study results. Although standardization is mentioned as a possible solution, it is not always clear how this could decrease or prevent irreproducible results in biomedical studies. In this article more insight is given into what quality, norms, standardization, certification, accreditation and optimized infrastructure can accomplish to reveal causes of irreproducibility and increase reproducibility when collecting biomaterials. CEN and ISO standards for the sample pre-analytical phase are currently being developed with the support of the SPIDIA4P project, and their role in increasing reproducibility in both biomedical research and diagnostics is demonstrated. In particular, it is described how standardized methods and quality assurance documentation can be exploited as tools for: 1) recognition and rejection of 'not fit for purpose' samples on the basis of detailed sample metadata, and 2) identification of methods that contribute to irreproducibility which can be adapted or replaced
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