Cereulide producing B. cereus and amylosin producing B. subtilis and B. mojavensis : characterization of strains and toxigenicities

B. cereus is one of the most frequent occurring bacteria in foods . It produces several heat-labile enterotoxins and one stable non-protein toxin, cereulide (emetic), which may be pre-formed in food. Cereulide is a heat stable peptide whose structure and mechanism of action were in the past decade elucidated. Until this work, the detection of cereulide was done by biological assays. With my mentors, I developed the first quantitative chemical assay for cereulide. The assay is based on liquid chromatography (HPLC) combined with ion trap mass spectrometry and the calibration is done with valinomycin and purified cereulide. To detect and quantitate valinomycin and cereulide, their [NH4+] adducts, m/z 1128.9 and m/z 1171 respectively, were used. This was a breakthrough in the cereulide research and became a very powerful tool of investigation. This tool made it possible to prove for the first time that the toxin produced by B. cereus in heat-treated food caused human illness. Until this thesis work (Paper II), cereulide producing B. cereus strains were believed to represent a homogenous group of clonal strains. The cereulide producing strains investigated in those studies originated mostly from food poisoning incidents. We used strains of many origins and analyzed them using a polyphasic approach. We found that the cereulide producing B. cereus strains are genetically and biologically more diverse than assumed in earlier studies. The strains diverge in the adenylate kinase (adk) gene (two sequence types), in ribopatterns obtained with EcoRI and PvuII (three patterns), tyrosin decomposition, haemolysis and lecithine hydrolysis (two phenotypes). Our study was the first demonstration of diversity within the cereulide producing strains of B. cereus. To manage the risk for cereulide production in food, understanding is needed on factors that may upregulate cereulide production in a given food matrix and the environmental factors affecting it. As a contribution towards this direction, we adjusted the growth environment and measured the cereulide production by strains selected for diversity. The temperature range where cereulide is produced was narrower than that for growth for most of the producer strains. Most cereulide was by most strains produced at room temperature (20 - 23ºC). Exceptions to this were two faecal isolates which produced the same amount of cereulide from 23 ºC up until 39ºC. We also found that at 37º C the choice of growth media for cereulide production differed from that at the room temperature. The food composition and temperature may thus be a key for understanding cereulide production in foods as well as in the gut. We investigated the contents of [K+], [Na+] and amino acids of six growth media. Statistical evaluation indicated a significant positive correlation between the ratio [K+]:[Na+] and the production of cereulide, but only when the concentrations of glycine and [Na+] were constant. Of the amino acids only glycine correlated positively with high cereulide production. Glycine is used worldwide as food additive (E 640), flavor modifier, humectant, acidity regulator, and is permitted in the European Union countries, with no regulatory quantitative limitation, in most types of foods. B. subtilis group members are endospore-forming bacteria ubiquitous in the environment, similar to B. cereus in this respect. Bacillus species other than B. cereus have only sporadically been identified as causative agents of food-borne illnesses. We found (Paper IV) that food-borne isolates of B. subtilis and B. mojavensis produced amylosin. It is possible that amylosin was the agent responsible for the food-borne illness, since no other toxic substance was found in the strains. This is the first report on amylosin production by strains isolated from food. We found that the temperature requirement for amylosin production was higher for the B. subtilis strain F 2564/96, a mesophilic producer, than for B. mojavensis strains eela 2293 and B 31, psychrotolerant producers. We also found that an atmosphere with low oxygen did not prevent the production of amylosin. Ready-to-eat foods packaged in micro-aerophilic atmosphere and/or stored at temperatures above 10 °C, may thus pose a risk when toxigenic strains of B. subtilis or B. mojavensis are present.

Diet and the development of atherosclerosis: a whole-diet approach from childhood to adulthood

Cardiovascular diseases (CVDs) are the leading cause of mortality in the world. Studies of the impact of single nutrients on the risk for CVD have often provided inconclusive results, and recent research in nutritional epidemiology with a more holistic whole-diet approach has proven fruitful. Moreover, dietary habits in childhood and adolescence may play a role in later health and disease, either independently or by tracking into adulthood. The main aims of this study were to find childhood and adulthood determinants of adulthood diet, to identify dietary patterns present among the study population and to study the associations between long-term food choices and cardiovascular health in young Finnish adults. The study is a part of the multidisciplinary Cardiovascular Risk in Young Finns study, which is an ongoing, prospective cohort study with a 21-year follow-up. At baseline in 1980, the subjects were children and adolescents aged 3 to 18 years (n included in this study = 1768), and young adults aged 24 to 39 years at the latest follow-up study in 2001 (n = 1037). Food consumption and nutrient intakes were assessed with repeated 48-hour dietary recalls. Other determinations have included comprehensive risk factor assessments using blood tests, physical measurements and questionnaires. In the latest follow-up, ultrasound examinations were performed to study early atherosclerotic vascular changes. The average intakes showed substantial changes since 1980. Intakes of fat and saturated fat had decreased, whereas the consumption of fruits and vegetables had increased. Intake of fat and consumption of vegetables in childhood and physical activity in adulthood were important health behavioural determinants of adult diet. Additionally, a principal component analysis was conducted to identify major dietary patterns at each study point. A similar set of two major patterns was recognised throughout the study. The traditional dietary pattern positively correlated with the consumption of traditional Finnish foods, such as rye, potatoes, milk, butter, sausages and coffee, and negatively correlated with fruit, berries and dairy products other than milk. This type of diet was independently associated with several risk factors of CVD, such as total and low-density lipoprotein cholesterol, apolipoprotein B and C-reactive protein concentrations among both genders, as well as with systolic blood pressure and insulin levels among women. The traditional pattern was also independently associated with intima media thickness (IMT), a subclinical predictor of CVD, in men but not in women. The health-conscious pattern, predominant among female subjects, non-smokers and urbanites, was characterised by more health-conscious food choices such as vegetables, legumes and nuts, tea, rye, fish, cheese and other dairy products, as well as by the consumption of alcoholic beverages. This pattern was inversely, but less strongly, associated with cardiovascular risk factors. Tracking of the dietary pattern scores was observed, particularly among subjects who were adolescents at baseline. Moreover, a long-term high intake of protein concurrent with a low intake of fat was positively associated with IMT. These findings suggest that food behaviour and food choices are to some extent established as early as in childhood or adolescence and may significantly track into adulthood. Long-term adherence to traditional food choices seems to increase the risk for developing CVD, especially among men. Those with intentional or unintentional low fat diets, but with high intake of protein may also be at increased risk for CVD. The findings offer practical, food-based information on the relationship between diet and CVD and encourage further use of the whole-diet approach in epidemiological research. The results support earlier findings that long-term food choices play a role in the development of CVD. The apparent influence of childhood habits is important to bear in mind when planning educational strategies for the primary prevention of CVD. Further studies on food choices over the entire lifespan are needed.

Genetic diversity and microcystin production by Anabaena in the Gulf of Finland, Baltic Sea

Syanobakteerit (sinilevät) ovat olleet Itämeressä koko nykymuotoisen Itämeren ajan, sillä paleolimnologiset todisteet niiden olemassaolosta Itämeren alueella ovat noin 7000 vuoden takaa. Syanobakteerien massaesiintymät eli kukinnat ovat kuitenkin sekä levinneet laajemmille alueille että tulleet voimakkaimmiksi viimeisten vuosikymmenien aikana. Tähän on osasyynä ihmisten aiheuttama kuormitus, joka rehevöittää Itämerta. Suomenlahti, jota tämä tutkimus käsittelee, on kärsinyt tästä rehevöitymiskehityksestä muita Itämeren altaita enemmän. Syanobakteerit muodostavat jokakesäisiä kukintoja Suomenlahdella - niin sen avomerialueilla kuin rannoillakin. Yleisimmät kukintoja muodostavat syanobakteerisuvut ovat Nodularia, Anabaena ja Aphanizomenon. Kukinnat aiheuttavat paitsi esteettistä haittaa myös terveydellisen riskitekijän. Niiden myrkyllisyys liitetään usein Nodularia-suvun tuottamaan nodulariini-maksamyrkkyyn. Itämeren Aphanizomenon-suvun on todettu olevan myrkytön. Vaikka Itämeren kukintoja aiheuttavista Nodularia- ja Aphanizomenon-syanobakteereista tiedetään varsin paljon, on molekyylimenetelmiin pohjautuva syanobakteeritutkimus ohittanut Itämeren Anabaena-suvun monelta osin. Tämän työn tarkoituksena oli syventää käsitystämme Itämeren Anabaena-syanobakteerista, sen mahdollisesta myrkyllisyydestä, geneettisestä monimuotoisuudesta ja fylogeneettisista sukulaisuussuhteista. Tässä työssä eristettiin 49 planktista Anabaena-kantaa, joista viisi tuottivat mikrokystiinejä. Tämä oli ensimmäinen yksiselitteinen todiste, että Itämeren Anabaena tuottaa maksamyrkyllisiä mikrokystiini-yhdisteitä. Jokainen eristetty myrkyllinen Anabaena-kanta tuotti useita mikrokystiini-variantteja. Lisäksi mikrokystiinejä löydettiin kukintanäytteistä, joissa oli myrkkyä syntetisoivia geenejä sisältäneitä Anabaena-syanobakteereita. Myrkkyjä löydettiin molempina tutkimusvuosina 2003 ja 2004. Myrkkyjen esiintyminen ei siten ollut vain yksittäinen ilmiö. Tässä työssä saimme viitteitä siitä, että maksamyrkyllinen Anabaena-syanobakteeri esiintyisi vähäsuolaisissa vesissä. Tämä riippuvuussuhde jää kuitenkin tulevien tutkimuksien selvitettäväksi. Tässä työssä havaittiin mikrokystiinisyntetaasi-geenien inaktivoituminen Itämeren Anabaena-kannassa ja kukintanäytteissä. Kuvasimme Anabaena-kannan mikrokystiinisyntetaasigeenien sisältä insertioita, jotka hyvin todennäköisesti inaktivoivat myrkyntuoton. Insertion sisältäneeltä kannalta löysimme kuitenkin kaikki mikrokystiinisyntetaasigeenit osoittaen, että geenien olemassaolo ei välttämättä varmista kannan mikrokystiinintuottoa. Mielenkiintoista oli se, että inaktivaation aiheuttavia insertioita löytyi kukintanäytteistä molemmilta tutkimusvuosilta. Vastaavia insertioita ei kuitenkaan löydetty makean veden Anabaena-kannoista tai järvinäytteistä. On yleistä, että syanobakteerikukinnoista löytyy usean syanobakteerisuvun edustajia. Myrkyllisiä sukuja tai lajeja ei voida kuitenkaan erottaa mikroskooppisesti myrkyttömistä. Käsillä olevassa tutkimuksessa kehitettiin molekyylimenetelmä, jolla on mahdollista määrittää kukinnan mahdollisesti maksamyrkylliset syanobakteerisuvut. Tätä menetelmää sovellettiin Itämeren kukintojen tutkimiseen. Itämeren pintavesistä ja ranta-alueiden pohjasta eristetyt Anabaena-kannat osoittautuivat geneettisesti monimuotoisiksi. Tämä Anabaena-syanobakteerien geneettinen monimuotoisuus vahvistettiin monistamalla geenejä suoraan kukintanäytteistä ilman kantojen eristystä. Makeiden vesien ja Itämeren Anabaena-kannat ovat geneettisesti hyvin samankaltaisia. Geneettisissä vertailuissa kävi kuitenkin ilmi, että pohjassa elävien Anabaena-kantojen geneettinen monimuotoisuus oli suurempaa kuin pintavesistä eristettyjen kantojen. Itämeren Anabaena-kantojen sekvenssit muodostivat omia ryhmiä sukupuun sisällä, jolloin on mahdollista, että nämä edustavat Itämeren omia Anabaena-ekotyyppejä. Tämä tutkimus oli ensimmäinen, jossa uusin molekyylimenetelmin systemaattisesti selvitettiin Itämeren Anabaena-syanobakteerin geneettistä populaatiorakennetta, fylogeniaa ja myrkyntuottoa. Tulevaisuudessa monitorointitutkimuksissa on otettava huomioon myös Itämeren Anabaena-syanobakteerin mahdollinen maksamyrkyntuotto – erityisesti vähäsuolaisemmilla rannikkovesillä.

Environmentally benign Fe chelates in plant nutrition

The low solubility of iron (Fe) depresses plant growth in calcareous soils. In order to improve Fe availability, calcareous soils are treated with synthetic ligands, such as ethylenediaminetetraacetic acid (EDTA) and ethylenediimi-nobis(2-hydroxyphenyl)acetic acid (EDDHA). However, high expenses may hinder their use (EDDHA), and the recalcitrance of EDTA against biodegra-dation may increase the potential of cadmium (Cd) and lead (Pb) leaching. This study evaluated the ability of biodegradable ligands, i.e. different stereo-isomers of ethylenediaminedisuccinic acid (EDDS), to provide Fe for lettuce (Lactuca sativa L.) and ryegrass (Lolium perenne cv. Prego), their effects on uptake of other elements and solubility in soils and their subsequent effects on the activity of oxygen-scavenging enzymes in lettuce. Both EDTA and EDDHA were used as reference ligands. In unlimed and limed quartz sand both FeEDDS(S,S) and a mixture of stereo-isomers of FeEDDS (25% [S,S]-EDDS, 25% [R,R]-EDDS and 50% [S,R]/[R,S]-EDDS), FeEDDS(mix), were as efficient as FeEDTA and FeEDDHA in providing lettuce with Fe. However, in calcareous soils only FeEDDS(mix) was comparable to FeEDDHA when Fe was applied twice a week to mimic drip irrigation. The Fe deficiency increased the manganese (Mn) concentration in lettuce in both acidic and alkaline growth media, whereas Fe chelates depressed it. The same was observed with zinc (Zn) and copper (Cu) in acidic growth media. EDDHA probably affected the hormonal status of lettuce as well and thus depressed the uptake of Zn and Mn even more. The nutrient concentrations of ryegrass were only slightly affected by the Fe availability. After Fe chelate splitting in calcareous soils, EDDS and EDTA increased the solubility of Zn and Cu most, but only the Zn concentration was increased in lettuce. The availability of Fe increased the activity of oxygen-scavenging enzymes (ascorbate peroxidase, guaiacol peroxidase, catalase). The activity of Cu/ZnSOD (Cu/Zn superoxide dismutase) and MnSOD in lettuce leaves followed the concentrations of Zn and Mn. In acidic quartz sand low avail-ability of Fe increased the cobalt (Co) and nickel (Ni) concentrations in let-tuce, but Fe chelates decreased them. EDTA increased the solubility of Cd and Pb in calcareous soils, but not their uptake. The biodegradation of EDDS was not affected by the complexed element, and [S,S]-EDDS was biodegraded within 28 days in calcareous soils. EDDS(mix) was more recalcitrant, and after 56 days of incubation water-soluble elements (Fe, Mn, Zn, Cu, Co, Ni, Cd and Pb) corresponded to 10% of the added EDDS(mix) concentration.

Lignocellulose degradation and humus modification by the fungus Paecilomyces inflatus

Composting is the biological conversion of solid organic waste into usable end products such as fertilizers, substrates for mushroom production and biogas. Although composts are highly variable in their bulk composition, composting material is generally based on lignocellulose compounds derived from agricultural, forestry, fruit and vegetable processing, household and municipal wastes. Lignocellulose is very recalcitrant; however it is rich and abundant source of carbon and energy. Therefore lignocellulose degradation is essential for maintaining the global carbon cycle. In compost, the active component involved in the biodegradation and conversion processes is the resident microbial population, among which microfungi play a very important role. In composting pile the warm, humid, and aerobic environment provides the optimal conditions for their development. Microfungi use many carbon sources, including lignocellulosic polymers and can survive in extreme conditions. Typically microfungi are responsible for compost maturation. In order to improve the composting process, more information is needed about the microbial degradation process. Better knowledge on the lignocellulose degradation by microfungi could be used to optimize the composting process. Thus, this thesis focused on lignocellulose and humic compounds degradation by a microfungus Paecilomyces inflatus, which belongs to a flora of common microbial compost, soil and decaying plant remains. It is a very common species in Europe, North America and Asia. The lignocellulose and humic compounds degradation was studied using several methods including measurements of carbon release from 14C-labelled compounds, such as synthetic lignin (dehydrogenative polymer, DHP) and humic acids, as well as by determination of fibre composition using chemical detergents and sulphuric acid. Spectrophotometric enzyme assays were conducted to detect extracellular lignocellulose-degrading hydrolytic and oxidative enzymes. Paecilomyces inflatus secreted clearly extracellular laccase to the culture media. Laccase was involved in the degradation process of lignin and humic acids. In compost P. inflatus mineralised 6-10% of 14C-labelled DHP into carbon dioxide. About 15% of labelled DHP was converted into water-soluble compounds. Also humic acids were partly mineralised and converted into water-soluble material, such as low-molecular mass fulvic acid-like compounds. Although laccase activity in aromatics-rich compost media clearly is connected with the degradation process of lignin and lignin-like compounds, it may preferentially effect the polymerisation and/or detoxification of such aromatic compounds. P. inflatus can degrade lignin and carbohydrates also while growing in straw and in wood. The cellulolytic enzyme system includes endoglucanase and β-glucosidase. In P. inflatus the secretion of these enzymes was stimulated by low-molecular-weight aromatics, such as soil humic acid and veratric acid. When strains of P. inflatus from different ecophysiological origins were compared, indications were found that specific adaptation strategies needed for lignocellulosics degradation may operate in P. inflatus. The degradative features of these microfungi are on relevance for lignocellulose decomposition in nature, especially in soil and compost environments, where basidiomycetes are not established. The results of this study may help to understand, control and better design the process of plant polymer conversion in compost environment, with a special emphasis on the role of ubiquitous microfungi.

Tuotantotekniikan ja säilytysajan vaikutus kasvihuonekurkkujen ja -tomaattien aistittavaan laatuun.

Finland has moved from growing vegetables by natural light to year-round greenhouse production using artificial lighting. Determination of sensory effects on greenhouse-grown vegetables is important as sensory evaluation provides information which chemical methods can not. It can tell us about the quality of samples which affects the consumers' behaviour. There are different opinions on how the quality of vegetables should be determined. The consumers are dissatisfied with the quality of vegetables and fruits, although the variety of products is larger than ever. The aim of this study was to find out how artificial lighting contributes to the sensory quality of greenhouse tomatoes and cucumbers compared to traditional natural lighting, and how storage affects the sensory attributes of the samples. In this study there were two sets of tomatoes and two sets of cucumbers, representing two different harvest seasons. Sensory evaluation involved two steps. The first step was to sort the samples and the second step was to generate a profile using descriptive analysis. Sorting was found to give some approximate information on differences between tomato and cucumber samples. MDS-maps dimensions were presented by age and lighting technique. The reliability of sorting results was quite good. The quality of the natural products was inconsistent. Production technology had more of an effect on cucumber samples than tomato samples. Natural light cucumbers were, for example sweeter and softer than artificial light cucumbers. Age had an especially large effect on cucumber appearance characteristics. There were less differences between tomato samples than cucumber samples. Production technology had less of an effect on tomato samples than age, e.g. hardness decreased during storage. In this study, it was found that artificial lighting has little effect on the sensory quality of Finnish greenhouse tomatoes compared with tomatoes grown under natural light.

Streptococcus milleri -ryhmä : Tunnistus lajitasolle ja esiintyvyys tietyissä infektioissa

S. milleri -ryhmän bakteerit ovat osa ihmisen suun, nielun, suoliston ja genitaalialueen normaaliflooran bakteeristoa. Kommensaalien lisäksi ryhmään kuuluu myös merkittäviä patogeenejä, jotka esiintyvät varsin runsaina löydöksinä monenlaisissa märkivissä infektioissa. Ryhmään kuuluu kolme lajia: S. anginosus, S. constellatus ja S. intermedius. Lajit ovat varsin samankaltaisia ja raportoidaankin usein vain ryhmänimellä. Lajit ovat kuitenkin erotettavissa, sillä ne eroavat toisistaan tuottamiensa entsyymien suhteen ja esiintyvyydessään kehon eri osissa. Työn tarkoituksena oli tunnistaa erityyppisistä kliinisistä infektioista otetuista näytteistä eristettyjä S. milleri -ryhmään luokiteltuja kantoja lajitasolle ja selvittää niiden esiintymisyleisyyttä näissä infektioissa. Näytteenottopaikat jaettiin viiteen ryhmään: naisten urogenitaalialue (15 kantaa), miesten urogenitaalialue (8 kantaa), oraaliset (28 kantaa), umpisuoli (34 kantaa) ja "muut" (12 kantaa). Lajitunnistuksen lisäksi selvitettiin kantojen hemolyyttisyys ja mahdollinen Lancefield-seroryhmä (A, C, F, G). Lajien erottelu perustuu eroihin bakteerien kyvyissä hajottaa tiettyjä substraatteja (entsyymiprofilointi), hemolyyttisyys määritettiin verimaljalla ja seroryhmitys tehtiin kaupallisella vasta-aine-sakkautumistestillä (Streptex latex Z1- 50). Työssä testattiin käytössä olevia ja kehiteltiin uusia, lähinnä ennalta muodostuneiden entsyymien tunnistamiseen perustuvia erottelumenetelmiä. Vertailtavina oli kolme entsyymiprofiliontimenetelmää, joista yksi on fluorogeeninen (4-Metyyli-umbelliferyyli-subtraatit) ja kaksi kromogeenistä (Weetabs ja RoscoDiagnostic tablets). Kannoilta määritettiin seuraavat aktiivisuudet: ?-fukosidaasi, (?-glukosidaasi, glukosidaasi, ?-galaktosidaaasi, ?-N-asetyyli-galaktosaminidaasi, ?-N-asetyyli-glukosaminidaasi, sialidaasi ja hyaluronidaasi. Työhön sisältyy myös erilaisten kasvatusalustojen sekä pH:n vaikutusten arviointia bakteerienentsyymiaktiivisuuksiin ja testituloksiin. Lisäksi työssä testattiin kromatografisensoluseinärasvahappoanalyysin soveltuvuutta lajien erotteluun. Menetelmiä tarkasteltiin herkkyyden sekäkäytännön suorittamisen ja aiheutuvien kustannusten kannalta. Asetetut tavoitteet saavutettiin. Kaikki käytetyt menetelmät osoittautuivat toimiviksi. Entsyymitestien tuloksetkorreloivat keskenään ja kirjallisuuden kanssa hyvin. Kannat karakterisoitiin, tunnistettiin lajitasolle ja lajiensiintyvyyttä kehon eri osissa voitiin vertailla. Mikään entsyymitesti ei osoittautunut ylivoimaisesti parhaaksi tai huonoimmaksi, vaikkakin yksittäistensubstraattien kohdalla eri testien herkkyydet vaihtelivatkin huomattavasti. Rasvahappoanalyysi ei erotellutkantoja toivotulla tavalla, joten sen käytöstä luovuttiin työn melko varhaisessa vaiheessa. Tutkituista 97 S. milleri -kannasta tunnistettiin 58 S. anginosus-kantaa, 29 S. constellatus-kantaa ja 10 S.ntermedius-kantaa. Eri lajit noudattivat entsyymiprofiiliaan muutamaa poikkeusta lukuunottamatta hyvinkinsäännöllisesti. Lajien sisäinen variaatio hemolyysiominaisuuksissa oli merkittävää ja S. inilleri -ryhmän erilajien sekä hemolyysisltään ja seroryhmältään erilaisten kantojen esiintyvyydessä kehon eri osissa havaittiinselkeitä eroja. Avainsanat: entsyymiprofilointi, fluorogeeniset ja kromogeeniset substraatit, seroryhmä, hemolyysi, esiintyvyys

Ravinnon hiilihydraattien glykemiaindeksin vaikutus keskiglukoosipitoisuuteen ja glukoosikäyrän alaiseen pinta-alaan henkilöillä, joilla on heikentynyt glukoosinsieto

Johdanto Korkeat aterianjälkeiset veren glukoosipitoisuushuiput ovat haitallisia verisuonille jo ennen varsinaisten diabeteskriteerien täyttymistä. Valitsemalla alhaisen glykemiaindeksin (GI) hiilihydraatteja ruokavalioon, voidaan veren glukoosipitoisuutta alentaa diabeetikoilla. Tyypin 2 diabeteksen lisääntymisen takia on tarpeellista etsiä keinoja ehkäistä sairauden puhkeamista riskiryhmissä. Glukoosimonitorilla on mahdollista seurata aiempaa tarkemmin glykemiaindeksin vaikutusta veren glukoosipitoisuuteen. Tavoitteet Selvittää, miten korvaamalla ruokavalion tavanomaiset hiilihydraatit joko korkean tai alhaisen GI:n hiilihydraateilla voidaan vaikuttaa vuorokauden keskiglukoosipitoisuuteen. Lisäksi tavoitteena oli selvittää, voidaanko vain hiilihydraattien laatua muuttamalla, puuttumatta niiden määrään tai muuhun ruokavalioon, vaikuttaa glukoosiaineenvaihduntaan henkilöillä, joilla on heikentynyt glukoosin sieto. Tutkittavat ja menetelmät Tutkimus toteutettiin satunnaistettuna vaihtovuorokokeena, jossa tutkittavina oli 56 51-73-vuotiasta henkilöä, joista naisia oli 41 ja miehiä 15. Tutkittavilla oli heikentynyt glukoosinsieto tai ruokavaliohoitoinen tyypin 2 diabetes. Tutkittavat korvasivat ruokavalionsa päähiilihydraatit 7-10 vuorokauden ajaksi glykemiaindeksiltään joko alhaiseksi (GI = 38) tai korkeaksi (GI = 72) arvioiduilla tutkimushiilihydraateilla. Kolmen viimeisen vuorokauden ajaksi tutkittaville asennettiin glukoosimonitoriin kytketty ihonalainen sensori, joka mittasi kudosnesteen glukoosipitoisuutta ja tutkimusjaksojen lopuksi tutkittaville tehtiin oraalinen glukoosirasituskoe. Tulokset Alhaisen GI:n ruokavaliolla kahden vuorokauden glukoosikäyrien alainen pinta-ala oli pienempi kuin korkean GI:n ruokavaliolla (16487 vs. 17270 mmol/l*48h; p = 0,009, n = 47). Vastaavasti kahden vuorokauden keskiglukoosipitoisuudet olivat 5,7 mmol/l ja 6,0 mmol/l, p = 0,009, n = 47. Glykosyloitunut hemoglobiini oli alhaisen GI:n ruokavalion jälkeen pienempi (5,33% vs. 5,38 %, p = 0,017, n = 53). Tutkittavien paino pieneni kummallakin ruokavaliolla; alhaisen GI:n ruokavaliolla 1,02 kg ja korkean GI:n ruokavaliolla 0,31 kg (p alle 0,001, n = 56). Vaikutusta plasman paastoglukoosiin ja seerumin paastoinsuliiniin ei ollut. Johtopäätökset Korvaamalla ruokavalion päähiilihydraatit alhaisen GI:n hiilihydraateilla, voidaan pitkäaikaista glukoositasoa pienentää ja näin ollen mahdollisesti ehkäistä heikentyneen glukoosinsiedon kehittymistä tyypin 2 diabetekseksi. Koska paastoglukoosipitoisuus ja paastoinsuliinipitoisuus eivät muuttuneet, lienee erityisesti aterianjälkeisillä glukoosihuipuilla merkitystä elimistön pitkäaikaiselle glukoositasolle henkilöillä, joilla on heikentynyt glukoosinsieto.

Äidinmaito - terveysjuomaa ja normaalibakteereita

The chemical composition of breast milk has been studied in detail in the past decades. Hundreds of new antibacterial and antiviral components have been found. Several molecules have been found to promote the proper function of neonatal intestine. However, microbiological studies of breast milk have been, until recently, focused mainly on detecting harmful and pathogenic bacteria and viruses. Natural microbial diversity of human milk has not been widely studied before the work reported in this thesis. This is mainly because breast milk has traditionally been thought to be sterile - even if a certain amount of commensal bacteria have usually been detected in milk samples. The first part of this licentiate thesis contains a short literature review about the anatomy and physiology of breast feeding, human milk chemical and microbiological composition, mastitis, intestinal flora and bacteriocins. The second part reports on the experiments of the licentiate work, concentrating on the microbial diversity in the milk of healthy breast-feeding mothers, and the ability of these bacteria to produce antibacterial substances against pathogenic bacteria. The results indicate that human milk is a source of commensal bacteria for infant intestine. 509 random isolates from 40 breast milk samples were isolated and identified by 16S rRNA sequencing. Median bacterial count was about 600 colony forming units per milliliter. Over half of the isolates were staphylococci, and almost one third streptococci. The most common species were skin bacteria Staphylococcus epidermidis and oral bacteria Streptococcus salivarius and Streptococcus mitis. Lactic acid bacteria, identified as members of Lactobacillus-, Lactococcus- and Leuconostoc -genera, were found in five milk samples. Enterococci were found in three samples. A novel finding in this study is the capability of these commensal bacteria to inhibit the growth of pathogens. In 90 precent of the milk samples commensal bacteria inhibiting the growth of Staphylococcus aureus were found. In 40 precent of samples the colonies could block the growth completely. One fifth of the isolated Staph. epidermidis strains, half of Str. salivarius strains, and all lactic acid bacteria and enterococci could inhibit or block the growth of Staph. aureus. In further study also Listeria innocua- and Micrococcus luteus active isolates were found in 33 and 11 precent of milk samples (out of 140). Furthermore, two Lactococcus lactis isolates from the breast milk were shown to produce bacteriocin nisin, which is an antimicrobial molecule used as a food preservative. The importance of these human milk commensal bacteria in the development of newborn intestinal flora and immune system, as well as in preventing maternal breast infections, should be further explored.

Median muotoilema : Muotoilun mediajulkisuus suomalaisessa talouslehdistössä

Designed by the Media The Media publicity of Design in the Finnish Economic Press The meaning of design has increased in consumer societies. Design is the subject of debate and the number of media discussions has also increased steadily. Especially the role of industrial design has been emphasised. In this study I examine the media publicity of design in the Finnish economic press from the late 1980s to the beginning of the 2000s. The research question is connected to media representations: How is design represented in the Finnish economic press? In other words, what are the central topics of design in the economic press, and to what issues are the media debates connected? The usually repeated phrase that design discussions take place only on the cultural pages of the daily press or in cultural contexts is being changed. Design is also linked to the consumer culture and consumers everyday practices. The research material has been collected from the Finnish economic press. The qualitative sample consists of articles from Kauppalehti, Taloussanomat and from several economic papers published by the Talentum Corporation. The approach of the research is explorative, descriptive and hermeneutic. This means that the economic press articles are used to explore how design is represented in the media. In addition, the characteristics of design represented in the media are described in detail. The research is based on the interpretive tradition of studying textual materials. Background assumptions are thus grounded in hermeneutics. Erving Goffman s frame analysis is applied in analysing the economic press materials. The frames interpreted from the articles depict the media publicity of design in the Finnish economic press. The research opens up a multidimensional picture of design in the economic press. The analysis resulted in five frames that describe design from various points of view. In the personal frame designers are described in private settings and through their personal experiences. The second frame relates to design work. In the frame of mastery of the profession, the designers work is interpreted widely. Design is considered from the aspects of controlling personal know-how, co-operation and the overall process of design. The third frame is connected to the actual substance of the economic press. In the frame of economy and market, design is linked to international competitiveness, companies competitive advantage and benefit creation for the consumers. The fourth frame is connected to the actors promoting design on a societal level. In the communal frame, the economic press describes design policy, design research and education and other actors that actively develop design in the societal networks. The last frame is linked to the traditions of design and above all to the examination of the cultural transition. In the frame of culture the traditions of design are emphasised. Design is also connected to the industrial culture and furthermore to the themes of the consumer culture. It can be argued that the frames construct media publicity of design from various points of view. The frames describe situations, action and the actors of design. The interpreted media frames make it possible to understand the relation of interpreted design actions and the culture. Thus, media has a crucial role in representing and recreating meanings related to design. The publicity of design is characterised by the five focal themes: personification, professionalisation, commercialisation, communalisation and transition of cultural focus from the traditions of design to the industrial culture and the consumer culture. Based on my interpretation these themes are guided by the mediatisation of design. The design phenomenon is defined more often on the basis of the media representations in the public discourses. The design culture outlined in this research connects socially constructed and structurally organised action. Socially constructed action in design is connected to the experiences, social recreation and collective development of design. Structurally, design is described as professional know-how, as a process and as an economic profit generating action in the society. The events described by the media affect the way in which people experience the world, the meanings they connect to the events around themselves and their life in the world. By affecting experiences, the media indirectly affects human actions. People have become habituated to read media representations on a daily basis, but they are not used to reading and interpreting the various meanings that are incorporated in the media texts.

Information, risk and trust in the food chain : Ex-ante valuation of consumer willingness to pay for beef quality information using the contingent valuation method

The safety of food has become an increasingly interesting issue to consumers and the media. It has also become a source of concern, as the amount of information on the risks related to food safety continues to expand. Today, risk and safety are permanent elements within the concept of food quality. Safety, in particular, is the attribute that consumers find very difficult to assess. The literature in this study consists of three main themes: traceability; consumer behaviour related to both quality and safety issues and perception of risk; and valuation methods. The empirical scope of the study was restricted to beef, because the beef labelling system enables reliable tracing of the origin of beef, as well as attributes related to safety, environmental friendliness and animal welfare. The purpose of this study was to examine what kind of information flows are required to ensure quality and safety in the food chain for beef, and who should produce that information. Studying the willingness to pay of consumers makes it possible to determine whether the consumers consider the quantity of information available on the safety and quality of beef sufficient. One of the main findings of this study was that the majority of Finnish consumers (73%) regard increased quality information as beneficial. These benefits were assessed using the contingent valuation method. The results showed that those who were willing to pay for increased information on the quality and safety of beef would accept an average price increase of 24% per kilogram. The results showed that certain risk factors impact consumer willingness to pay. If the respondents considered genetic modification of food or foodborne zoonotic diseases as harmful or extremely harmful risk factors in food, they were more likely to be willing to pay for quality information. The results produced by the models thus confirmed the premise that certain food-related risks affect willingness to pay for beef quality information. The results also showed that safety-related quality cues are significant to the consumers. In the first place, the consumers would like to receive information on the control of zoonotic diseases that are contagious to humans. Similarly, other process-control related information ranked high among the top responses. Information on any potential genetic modification was also considered important, even though genetic modification was not regarded as a high risk factor.