193 research outputs found
ToksiÄno djelovanje kadmija i pojava rezistencije u euglene
By monitoring the fate of individual Euglena cells on agar plates, extreme sensitivity to low concentrations of cadmium ions during cell division was detected. Toxic effects of cadmium were somewhat more pronounced in the light. The antagonistic role of zinc was confirmed.
In etiolated Euglena cadmium inhibited chlorophyll and carotenoid synthesis. The protective role of the resting medium in comparison to the rich Euglena medium is attributed to differences in susceptibility to cadmium in different physiological states of the cells.
The properties of a cadmium resistant clone were investigated. This clone contained half the amount of chlorophyll normally present in Euglena, and the normal amount of carotenoids. On the submicroscopie level, most changes occurred in the chloroplasts. All stages from severely disorganized chloroplasts characterized by dilated and swollen thylakoids, to normal cells, were observed. Similarities with changes occurring during adaptation to the herbicide DCMU are discussed.PraÄenjem sudbine pojedinaÄnih stanica na povrÅ”ini agara dokazana je velika osjetljivost staniÄne diobe u euglene na toksiÄno djelovanje niskih koncentracija kadmija.
PotvrÄeno je antagonistiÄko djelovanje cinka.
U etioliranoj eugleni kadmij inhibira sintezu klorofila i karoteno- ida. ZaÅ”titna uloga mirujuÄeg medija u usporedbi s bogatim Euglena medijem pripisuje se razliÄitoj osjetljivosti euglene kod raznih fizioloÅ”kih stanja stanica.
Istraživana su svojstva klona rezistentnog na kadmij, koji je imao smanjenu koncentraciju klorofila (oko 50%) kroz viÅ”e uzastopnih generacija. Istovremeno je sadržaj karotenoida ostao nepromijenjen u odnosu na kontrolu. U submikroskopskom podruÄju najviÅ”e promjena se dogodilo u strukturi kloroplasta. NaÄeni su svi prijelazi od vrlo oÅ”teÄenih kloroplasta s karakteristiÄnim razmaknutim i nabubralim tilako- idima, do kloroplasta s normalnom strukturom. Razmatra se sliÄnost s promjenama koje se deÅ”avaju za vrijeme adaptacije euglene na herbicid DCMU
Svojstva i struktura bezbojne mutante vrste Euglena gracilis
The structure and growth were examined in a white, completely pigmentless, mutant of Euglena gracilis. Although it lacks any pigments, coloured stigma and defined plastids, some non-osmiophilic structures resembling stigma vesicles and, possibly, very aberrant remnants of plastids appear in this strain. The value of the exact characterization of bleached mutants is discussed.Istraživani su rast i ultrastruktura bijele bezbojne mutante vrste Euglena gracilis. Iako bez pigmenta, u stanicama postoje ostaci stigme i plastida, koji sadržavaju samo koncentriÄne lamele i ostatke globula.
Ukazano je na potrebu toÄnije karakterizacije izblijeÄenih mutanti euglena
Changes in the Chloroplast-Ultrastructure of Netrium digitus (Desmidiaceae) after a Period of Darkness
WƤhrend in den belichteten Zellen von Netrium digitus die Chloro- plasten vorwiegend ein undifferenziertes Thylakoidsystem besitzen, kommt bei mehr als 10 Tage dauernden Lichtabschluss vorwiegend eine granaƤhnliche Struktur zum Vorschein. Nach etwa 4 Wochen Verdunkelung treten dagegen irreversible VerƤnderungen ein, die ein Absterben der Zellen zur Folge haben.U osvijetljenim stanicama vrste Netrium digitus veÄina kloroplasta sadrži manje-viÅ”e nediferencirani sistem tilakoida. Nakon perioda tame (10 dana ili viÅ”e) u kloroplastima javljaju se pretežno strukture sliÄne grana-podruÄjima (Ā»pseudogranaĀ«).In illuminated cells of Netrium digitus the majority of the ehloro- plasts contains a more or less undifferentiated thylakoid system. After periods of darkness (of ten days and more) a predominant grana-like structure (Ā»pseudogranaĀ«) appears in the chloroplasts
Djelovanje 1-0-(indol-3ā-ilacetil)-Ć-D-glukopiranoze i indol-3-iloctene kiseline na neke jednostaniÄne zelene alge
The results of the present study have thus shown that low concentrations (0.01ā1.0 micro M) of IAA and IA0G do not stimulate the division of the unicellular algae tested.
High concentrations of IAA and IA0G (10-3 M), tested only on Chlamydomonas reinhardii, inhibited the cell division with subsequent loss of flagella and giant cell formation.
The results indicate a lower toxicity of IA0G in comparison to the effect of IAA.
I am indebted to Dr. D. Keglevic for the sample of 1-0-(Indol-3ā-ylacetyl)-0-D-glucopyranose and to Dr. M. Pokorny for carrying out the thin layer chromatography.Niske koncentracije IAA i IAĆG (0,01ā1,0 uM) ne stimuliraju diobu ispitivanih jednostaniÄnih alga.
Visoke koncentracije IAA i IAĆG (10-3 m), koje su ispitane samo na vrsti Chlamydomonas reinhardii, inhiibiraju staniÄnu diobu uz gubitak biÄeva i pojavu gigantskih stanica.
Rezultati ukazuju na slabiju toksiÄnost IAĆG u usporedbi s uÄinkom IAA
MeÄusobni odnos mineralne ishrane i temperature na rast vrste Euglena gracilis
In Euglena gracilis strain Ā»ZĀ« grown in the complex medium (on a repetitive light-dark cycle) the need for exogenous nutrients rises with temperature. At 18 Ā°C no need in added nutrients has been observed.
The rate of growth as expressed in increase in cell number, amount of chlorophyll and carotenoids rises at higher temperatures with additional phosphates (K2HP04 and KH2PO4), mixture of microelements and magnesium sulphate.
Addition of ammonium mono-H orthophosphate at the concentration used inhibits cell division but does not affect chlorophyll synthesis, and cells with very high chlorophyll concentration are obtained.
The study indicates that the illumination regimen induces marked differences in the relative rates of cellular biosynthesis.Potreba za dodatkom pojedinih soli kompleksnom mediju za uzgoj vrste Euglena gracilis soj Ā»ZĀ« raste s poviÅ”enjem temperature. Kod 18Ā° nema potrebe u dodatnim hranidbenim tvarima.
Dodatkom amonijevog fosfata (K2HP04 i KH2PO4), mjeÅ”avine mikro- elemenata i magnezijevog sulfata, s porastom temperature poveÄava se brzina rasta izražena porastom broja stanica, porastom koliÄine klorofila i karotenoida.
Dodatak amonijevog fosfata pri upotrebljenoj koncentraciji djeluje inhibitorno na diobu stanica, ali ne i na sintezu klorofila, tako da se dobivaju stanice s vrlo visokom koncentracijom klorofila.
Istraživanja pokazuju da režim osvjetljavanja izaziva znatne razlike u relativnim odnosima biosintetskih funkcija stanice
Der Effekt des Belichtungsregimes auf das Temperatur-Induzierte und spontane Ausbleichen von Euglena gracilis
Ustanovljeno je, da je postotak bezbojnih euglena (bilo nastalih spontano, bilo indukcijom kod poviÅ”ene temperature) u kontinuirano osvijetljenim kulturama znaÄajno poviÅ”en u odnosu na periodiÄki osvijetljene kulture (14 h svjetlosti: 10 h tame).Es wird gezeigt, dass bei kontinuierlich belichteten Kulturen von Euglena gracilis der Prozentsatz der sowohl temperaturbedingt als auch spontan entstehenden apochlorotischen Kolonien in bezug auf die periodisch belichteten Kulturen (14 Std Licht: 10 Std Dunkelheit) signifikant hƶher ist
ToksiÄno djelovanje kadmija i pojava rezistencije u euglene
By monitoring the fate of individual Euglena cells on agar plates, extreme sensitivity to low concentrations of cadmium ions during cell division was detected. Toxic effects of cadmium were somewhat more pronounced in the light. The antagonistic role of zinc was confirmed.
In etiolated Euglena cadmium inhibited chlorophyll and carotenoid synthesis. The protective role of the resting medium in comparison to the rich Euglena medium is attributed to differences in susceptibility to cadmium in different physiological states of the cells.
The properties of a cadmium resistant clone were investigated. This clone contained half the amount of chlorophyll normally present in Euglena, and the normal amount of carotenoids. On the submicroscopie level, most changes occurred in the chloroplasts. All stages from severely disorganized chloroplasts characterized by dilated and swollen thylakoids, to normal cells, were observed. Similarities with changes occurring during adaptation to the herbicide DCMU are discussed.PraÄenjem sudbine pojedinaÄnih stanica na povrÅ”ini agara dokazana je velika osjetljivost staniÄne diobe u euglene na toksiÄno djelovanje niskih koncentracija kadmija.
PotvrÄeno je antagonistiÄko djelovanje cinka.
U etioliranoj eugleni kadmij inhibira sintezu klorofila i karoteno- ida. ZaÅ”titna uloga mirujuÄeg medija u usporedbi s bogatim Euglena medijem pripisuje se razliÄitoj osjetljivosti euglene kod raznih fizioloÅ”kih stanja stanica.
Istraživana su svojstva klona rezistentnog na kadmij, koji je imao smanjenu koncentraciju klorofila (oko 50%) kroz viÅ”e uzastopnih generacija. Istovremeno je sadržaj karotenoida ostao nepromijenjen u odnosu na kontrolu. U submikroskopskom podruÄju najviÅ”e promjena se dogodilo u strukturi kloroplasta. NaÄeni su svi prijelazi od vrlo oÅ”teÄenih kloroplasta s karakteristiÄnim razmaknutim i nabubralim tilako- idima, do kloroplasta s normalnom strukturom. Razmatra se sliÄnost s promjenama koje se deÅ”avaju za vrijeme adaptacije euglene na herbicid DCMU
VariabilitƤt der Stachelform und der Coenobienbildung eines Stammes von Scenedesmus quadricauda (Turpin) BrƩbisson
Scenedesmus quadricauda izoliran iz bazena BotaniÄkog vrta u Zagrebu uzgojen je u Äistoj kulturi. ProuÄavane su promjene oblika i položaja bodlji te stvaranje jednostaniÄnih populacija. Prolazne nepravilnosti u obliku i rasporedu bodlji primijeÄene su kod rasta u starim kulturama, u hranidbenim otopinama s visokom koncentracijom soli kao i kod rasta u filtra tima kulture Euglene. JednostaniÄne populacije kao i oblici bez bodlji pojavile su se naroÄito kod sniženja pH medija na 5ā5,6.Scenedesmus quadricauda wurde aus einem Becken des Botanischen Gartens in Zagreb isoliert und bakterienfrei kultiviert. Coenobienformwechsel und Einzellen-Bildung wurden studiert. VorĆ¼bergehende Anomalien in Form und Verteilung der Stacheln konnten in alten Kulturen, in NƤhrlƶsungen mit hoher Salzkonzentration und nach Kultivieren in Eugenakultur-Filtraten beobachtet werden. Einzellige sowie stachelfreie Formen konnten besonders durch Herabsetzen des pH des Mediums auf 5 ā 5,6 induziert werden
Djelovanje N-fenil-izopropil-karbamata na euglenu
The effects of the herbicide isopropyl NāN phenylcarbamate (IPC) on wild type Euglena and three bleached mutants (yellow, pale yellow and white) have been studied.
IPC is a slowly acting, rather weak, herbicide which inhibits cell division in all Euglena strains studied. This inhibition depends on the nutritional history of cells and the adaptability of the strain to the ethanol used to dissolve IPC.
Wild type Euglena is most sensitive to IPC, especially if cultured in the light, although the lethal dose has been found to be the same for all strains studied (10-3 M).
Most metabolic changes, such as appearance of monstrous forms, and inhibition of chlorophyll and paramylum synthesis, are seen at an intermediate dose of about 5 X 10-4 M.
IPC does not cause bleaching i. e. irreversible permanent loss of chloroplasts.
This study confirms that IPC does not only act on autotrophic plant cells, but on cells of heterotrophic organisms as well.ProuÄavano je djelovanje herbicida N-fenil-izopropil-karbamata (IPC) na divlji tip euglene i njene izblijeÄene mutante (žutu, blijedo žutu i bijelu).
IPC je sporo-djelujuÄi, dosta slab herbicid, koji inhibira staniÄnu diobu u svim prouÄavanim sojevima euglene. Ova inhibicija ovisi o prethodnim hranidbenim uvjetima i prilagodljivosti dotiÄnog soja na etanol u kojem je IPC otopljen.
Divlji tip euglene je pokazao najveÄu osjetljivost na IPC, naroÄito pri uzgoju na svjetlosti, iako je letalna doza (10-3 M) ista za sve prouÄavane sojeve.
VeÄina metaboliÄkih promjena, kao Å”to su pojava monstruoznih oblika, inhibicija sinteze klorofila i paramiluma opaža se kod srednje doze od gko 5X10-4 M.
IPC ne izaziva izbljeÄivanje tj. ireverzibilni trajni gubitak kloroplasta.
Ovo istraživanje potvrÄuje da IPC ne djeluje samo na autotrofnu biljnu stanicu veÄ takoÄer i na stanice heterotrofnih organizama
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