Biochemical characterization of the Arctic char (<it>Salvelinus alpinus</it>) ovarian progestin membrane receptor

<p>Abstract</p> <p>Membrane progestin receptors are involved in oocyte maturation in teleosts. However, the maturation-inducing steroid (MIS) does not appear to be conserved among species and several progestins may fulfill this function. So far, complete biochemical characterization has only been performed on a few species. In the present study we have characterized the membrane progestin receptor in Arctic char (Salvelinus alpinu<it>s</it>) and show that the 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) receptor also binds several xenobiotics, thus rendering oocyte maturation sensitive to environmental pollutants. We identified a single class of high affinity (K_d, 13.8 ± 1.1 nM), low capacity (B_max, 1.6 ± 0.6 pmol/g ovary) binding sites by saturation and Scatchard analyses. Receptor binding displayed rapid association and dissociation kinetics typical of steroid membrane receptors, with t_1/2s of less than 1 minute. The 17,20beta-P binding also displayed tissue specificity with high, saturable, and specific 17,20beta-P binding detected in ovaries, heart and gills while no specific binding was observed in muscle, brain or liver. Changes in 17,20beta-P binding during oocyte maturation were consistent with its identity as the oocyte MIS membrane receptor. Incubation of fully-grown ovarian follicles with gonadotropin induced oocyte maturation, which was accompanied by a five-fold increase in 17,20beta-P receptor binding. In addition, competition studies with a variety of steroids revealed that receptor binding is highly specific for 17,20beta-P, the likely maturation-inducing steroid (MIS) in Arctic char. The relative-binding affinities of all the other progestogens and steroids tested were less than 5% of that of 17,20beta-P for the receptor. Several ortho, para derivatives of DDT also showed weak binding affinity for the 17,20beta-P receptor supporting the hypothesis that xenobiotics may bind steroid receptors on the oocyte's surface and might thereby interfere with oocyte growth and maturation.</p

Comparison and Evaluation of Multiple Users' Usage of the Exposure and Risk Tool: Stoffenmanager 5.1.

Stoffenmanager is an exposure and risk assessment tool that has a control banding part, with risk bands as outcome and a quantitative exposure assessment part, with the 90th percentile of the predicted exposure as a default outcome. The main aim of the study was to investigate whether multiple users of Stoffenmanager came to the same result when modelling the same scenarios. Other aims were to investigate the differences between outcomes of the control banding part with the measured risk quota and to evaluate the conservatism of the tool by testing whether the 90th percentiles are above the measured median exposures. We investigated airborne exposures at companies in four different types of industry: wood, printing, metal foundry, and spray painting. Three scenarios were modelled and measured, when possible, at each company. When modelled, 13 users visited each company on the same occasion creating individual assessments. Consensus assessments were also modelled for each scenario by six occupational hygienists. The multiple users' outcomes were often spread over two risk bands in the control banding part, and the differences in the quantitative exposure outcomes for the highest and lowest assessments per scenario varied between a factor 2 and 100. Four parameters were difficult for the users to assess and had a large impact on the outcome: type of task, breathing zone, personal protection, and control measures. Only two scenarios had a higher measured risk quota than predicted by the control banding part, also two scenarios had slightly higher measured median exposure value than modelled consensus in the quantitative exposure assessment part. Hence, the variability between users was large but the model performed well

Assessment of pond and integrated aquaculture (IAA) systems in six districts of Tanzania

Integrated agriculture and aquaculture systems (IAA) are well known for their ability to improve the overall farm productivity and profitability. This is through recycling of on-farm resources, such as nutrient rich fish pond water and agriculture remains that would otherwise be considered as wastes. The present study explores the existing and potential IAA systems in Tanzania. It also examines management strategies and their influence on fish yield and the economic returns between IAA and non-IAA fish farming. The study assesses farmer’s socio-demographic characteristics and their perception towards fish farming. The study was conducted through an on-site survey of 129 fish ponds owned by 89 farmers in six districts in Tanzania, involving 65 and 64 IAA and non-IAA ponds respectively. Results indicate that tilapia-vegetables is the most common type of IAA practiced by fish famers. Despite higher fish feed use and stocking density in non-IAA ponds, IAA ponds had an average fish yield of 2.46 t ha-1, which was significantly (p0.05) higher than the fish yield of 1.54 t ha-1 found for non-IAA ponds. IAA ponds had also 1.6 and 2.9 times higher (p 0.05) revenue and net profit, respectively, than non-IAA ponds. Additionally, the net return from IAA ponds in an integrated system was significantly (p0.05) higher than when practiced as stand-alone activities. IAA famers were more positive towards fish farming compared to non-IAA farmers. Thus, IAA systems should be promoted among small-scale farmers to cover for an increased fish demand and to improve food security

Integration of Nile tilapia (Oreochromis niloticus) and vegetables (Amaranthus hybridus and Brassica rapa pekinensis) for improved production, water use efficiency and nutrient recycling

Sustainable agriculture intensification is an urgent challenge in developing countries including Tanzania. One potential solution is to adopt farming systems that increase farm production by optimizing resource use efficiency, and integrated aquaculture system, which involves farming of fish and crops, is an example of such systems. This study investigated the impact of Integrated agriculture and aquaculture (IAA) farming on water use efficiency, fish and vegetable production and overall system profitability, and how these parameters are affected by fish stocking densities. Oreochromis niloticus (2.5 g average initial weight) were cultured at low stocking density (five fish m−3, LSD), medium stocking density (eight fish m−3, MSD), and high stocking density (12 fish m−3, HSD) for 205 days. Brassica rapa pekinensis and Amaranthus hybridus cultivated adjacent to the fish tanks were irrigated with; (i) fish tank water, without any fertilizer inputs; (ii) fish tank water, partially fertilized; (iii) tap water, fully fertilized (farmers’ practice); and (iv) tap water without any fertilizer inputs. Although the use of tank water from the high fish stocking density resulted in significantly higher vegetable yield, high fish stocking resulted in lower fish growth, profitability and water use efficiency compared to the other fish stocking densities, probably because of low survival rates (28%) at high stocking densities. The integration of fish at a medium stocking density with vegetables resulted in significantly higher net income than when fish and vegetables were grown separately

Characterization of antibodies for quantitative determination of spiggin protein levels in male and female three-spined stickleback (Gasterosteus aculeatus)

Spiggin is an adhesive glycoprotein produced in the kidney of sticklebacks during the breeding season and is subsequently secreted into the urinary bladder from where it is employed for nest building. Since the production of the protein has been shown to be under androgenic control, spiggin has been suggested to be a useful biomarker for androgenic substances in the environment. In this study, two polyclonal spiggin antibodies based on synthetic peptides and one polyclonal antibody directed against native spiggin have been characterized. The antibodies ability to identify spiggin was investigated by quantitative immunoassay. For both peptide antibodies the quantification range was determined to be between 1 and 80 ng spiggin and determination of renal spiggin levels from immature and mature males displayed a 15-fold increase in total spiggin content of the kidney resulting in a 6-fold increase in male kidney weight due to hypertrophy. The kidney somatic index (KSI) was found to correlate well with the total renal spiggin content and therefore it appears that KSI in sticklebacks could be used as an initial method to identify substances displaying androgenic effects. Furthermore, western blot analysis revealed that the polyclonal antibodies recognize different spiggin isoforms and that spiggin can be detected in the urinary bladder and kidney of both males and female sticklebacks. In order to develop a quantitative detection method for native spiggin it is necessary to produce a standard that can be used in a bioassay. Due to the adhesive and polymerization characteristics of spiggin the protein is difficult to use as a standard in bioassays. So far spiggin has been shown to exist in at least 14 isoforms, all of which contain polymerization domains. To overcome the solubility problem we have produced recombinant spiggin gamma, with only one polymerization domain, that can be expressed in E. coli. Western blot analysis demonstrated that the polyclonal antibodies were able to detect recombinant spiggin gamma protein in bacterial cell lysate, suggesting that it may be developed into a useful source of standard spiggin to be used for quantitative determination of androgen induced spiggin production in sticklebacks

Lawn as a cultural and ecological phenomenon: A conceptual framework for transdisciplinary research

AbstractGlobalisation and urbanisation are driving the worldwide homogenisation of urban landscapes. The flora and fauna of cities in different parts of the world are very similar, irrespective of geography and climate. One of the most powerful symbols of modern urban landscapes is the lawn. There are just a few management options for urban lawns, regardless of how they are used and where in the city they are situated. Today, lawns occupy much of the green open spaces in cities (70–75%) and are located in private front and rear gardens, public parks, cemeteries, golf courses and along roads. Most people in the Western world view lawns as a ‘natural’ and even compulsory element of the urban landscape, without questioning their social, symbolic, ecological or aesthetic values. In this article we discuss the conceptual framework and methodological approaches being used in an ongoing transdisciplinary collaboration project including stakeholders to study lawns in Sweden as a social and ecological phenomenon. The overall aim is to understand the role of lawns in sustainable urban planning, design and management. The transdisciplinary approach allows us to exchange knowledge between scientific disciplines in order to influence the studies within each subject throughout the project and to achieve a multi-dimensional understanding of the lawn as a phenomenon. The involvement and close collaboration of stakeholders in the project allows us to obtain first-hand information on planning issues connected to lawns and existing planning data from cities and to focus on true implementation aspects rather than just theoretical recommendations

Molecular cloning and characterization of a nuclear androgen receptor activated by 11-ketotestosterone

Although 11-ketotestosterone is a potent androgen and induces male secondary sex characteristics in many teleosts, androgen receptors with high binding affinity for 11-ketotestosterone or preferential activation by 11-ketotestosterone have not been identified. So, the mechanism by which 11-ketotestosterone exhibits such high potency remains unclear. Recently we cloned the cDNA of an 11-ketotestosterone regulated protein, spiggin, from three-spined stickleback renal tissue. As spiggin is the only identified gene product regulated by 11-ketotestosterone, the stickleback kidney is ideal for determination of the mechanism of 11-ketotestosterone gene regulation. A single androgen receptor gene with two splicing variants, belonging to the androgen receptor-β subfamily was cloned from stickleback kidney. A high affinity, saturable, single class of androgen specific binding sites, with the characteristics of an androgen receptor, was identified in renal cytosolic and nuclear fractions. Measurement of ligand binding moieties in the cytosolic and nuclear fractions as well as to the recombinant receptor revealed lower affinity for 11-ketotestosterone than for dihydrotestosterone. Treatment with different androgens did not up-regulate androgen receptor mRNA level or increase receptor abundance, suggesting that auto-regulation is not involved in differential ligand activation. However, comparison of the trans-activation potential of the stickleback androgen receptor with the human androgen receptor, in both human HepG2 cells and zebrafish ZFL cells, revealed preferential activation by 11-ketotestosterone of the stickleback receptor, but not of the human receptor. These findings demonstrate the presence of a receptor preferentially activated by 11-ketotestosterone in the three-spined stickleback, so far the only one known in any animal

Vandringsmönster hos GPS-försedda älgar i GRENSEVILT – konsekvenser för förvaltningen

Att olika arter av däggdjur vandrar mellan olika områden under året (sk säsongsvandringar) förekommeri många områden världen över. Hos hjortdjur såsom älg, kronhjort och rådjur i det boreala skogszonen tycks benägenheten att vandra vara starkt kopplad till typen av levnadsmiljö där den säsongsmässiga variationen i klimatet är en viktig drivande faktor. Benägenhetenatt säsongsvandra medför också stora konsekvenser för förvaltningen av älg och skog eftersom älgarna förflyttar sig över administrativa gränser och mellan olika förvaltningsområden. En av de viktigaste målsättningarna inom forskningsprojektet GRENSEVILT har varit att skapa bättre förutsättningar för förvaltningen av älg hos en älgpopulation som lever längs den svensk-norska gränsen i Värmlands och Dalarnas län samt Innlandet fylke genom att studera älgarnas rörelsemönster. Under vintern 2018, 2019 och 2020 försågs 30 kor och 11 tjurar med GPS-sändare i detta område. GPS-halsbanden blev programmerade till att positionera i regelmässiga intervaller om 2 timmar. Studien omfattar data från de 41 radiomärkta älgarna från det första märkningstillfälleti februari 2018 fram till hösten 2021. Av dessa uppvisade 20 (49%) ett strikt migrerande vandringsmönster mellan sommar och vinterområden, 14 (34%) nyttjade samma område både vinter och sommar och varstationära. De resterande 7 (17%) uppvisade en kombination av dessa två typer av rörelsemönster mellan olika år. Det fanns inga statistiskt säkerställda skillnader mellan könen i fördelningen av rörelsemönster. Medeldatum för de migrerande älgkornas start och slut på vårvandringen var 20 respektive 30 april medan tjurarna startade sin vårvandring i medeltal den 30 april och anlände till sommarområdet 16 maj. De flesta älgarna migrerade till sina vinterområden under december och januari där 49% hade anlänt till vinterområdet den 1 januari medan 92% hade anlänt den 1 februari. I medeltal vandrade tjurarna 52 km (linjärt avstånd)från sommar till vinterområdet medan korna vandrade 19 km. Den längsta vandringssträckan mellan säsongs-hemområden för tjurar var 87 km och förkor 38 km. Det fannsstatistiskt säkerställda skillnader mellan de olika åren för när under året som säsongsvandringarna startade och avslutades. En motsvarande variation mellan år kunde även identifieras för snödjupet och den totala snöperiodens längd. Vandringarna skedde till största delen från mer syd-ostligt belägna vinterområden i Sverige under våren till mer nord-västligt belägna områden i Norge.Medelstorleken på årliga hemområden för stationära kor och tjurar var 6700 respektive 9200 ha medan detta för migrerande kor och tjurar var 17 000 respektive 65 000 ha. Bland de stationära älgarna berörde huvuddelen (70%) endast ett förvaltningsområde medan 59% av de migrerande älgarnas rörelser överlappade 3-5 olika administrativa förvaltningsenheter under ett år. Resultaten visaratt mer än hälften av älgarna nyttjar olika områden under vintern och under den del av jakttiden där den absoluta majoriteten av älgarna fälls vilket medför en ojämn fördelning mellan kostnader (skogsskador) och intäkter (jaktuttag) mellan olika områden. Ett hårt betestryck och omfattande skogsskador under vintern i ett område styrs därmed till största delen av den rådande älgförvaltningen 10-50 km därifrån och som i detta studieområde huvudsakligen ligger i nordlig och nord-västlig riktning. En framtida förvaltningsstrategi bör ske över ÄFO och kommungränser, över läns-och fylkesgränser och i vissa områden även över nationsgränser som i detta fall utgörs av den mellan Sverige och Norge