Mallomonas acaroides Perty emend. Ivanov bloom in the Calcescu subalpine lake of the Pagang Mountains, Romania

Mallomonas acaroides Perty emend. Ivanov bloom in the Calcescu subalpine lake of the Parang Mountains, Romania. Plankton samples collected in autumn 1992 from the glacial Calcescu Lake, located at an altitude of 1924 m in the Parang Mountains, southern Carpathians, revealed an unexpected bloom of Mallomonas acaroides var. acaroides. according to TEM observations the population was very uniform, exhibited individuals with elongated, ellipsoidal to almost cylindrical cells bearing all over their surface outstandingly long, slender bristles, with helmet shaped tips. Bristles lacking helmet shaped tips, with gradually tapering distal ends and recurved proximal teeth were also present, but very rare. Most individuals possessed very thin, poorly silicified, imbricated scales, mostly without or with rudimentary meshwork on the shield. This is the first record of such Mallomonas bloom in a Romanian alpine lake, very similar with that documented by Kristiansen in a Bulgarian mountain lake

Adatok a Baláta-tó algaflórájához

Halász (1943) és Uherkovich (1978) 177 faj előfordulását közölte a Baláta-tóból. 1991-ben, valamint 1995-1996-ban végzett vizsgálataink során további 137 taxon került elő, melyek közül számos faj egyúttal Magyarország flórájára nézve is új. A flóra különösen gazdag Desmidiales és Synurophyceae fajokban. A talált fajok egy része kizárólag savas vizekben, lápokon fordul elő, mások kevésbé specializáltak, sőt néhány alkalikus, hipertróf vizekből is előkerül. Mindezek alapján a Baláta-tó átmeneti lápnak minősíthető. Vizsgálataink megerősítik Boros (1924) századeleji megállapítását, amely szerint a Baláta-tó és a Rétyi Nyír (Erdély, Kovászna megye) között igen nagy a florisztuikai hasonlóság

Recent occurrence of Mallomonas intermedia Kisselev (Synurophyceae, Chrysophyta) in Transylvania (Romania), based on scanning electron microscopy

Plankton samples collected from a yellow watered bog pool of the mesotrophic “Călăţele Pădurii” peat bog (Romanian Western Mountains, Transylvania), exhibited an outstandingly rich Mallomonas population. The observations carried out by light and scanning electron microscopy revealed that the population belongs to Mallomonas intermedia Kisselev. Based on the presence of lance head bristles, distributed all over the cell armour (except few anterior collar, unilaterally serrated ones), it became evident that the population belong to the nominate variety (var. intermedia). Mallomonas intermedia var. saliceaensis formerly described from Transylvania differs by the type variety by the presence of exclusively serrated bristles. The present finding proved that Mallomonas intermedia could not be properly identified at infraspecific level solely based on the ultra structure of scales, without knowing the structure of bristles too

Incorporation of carotenoid esters into liposomes

Carotenoid esters are investigated for their interaction with liposomal membranes and compared with their corresponding free (non-esterified) carotenoids. A monoester (beta-cryptoxanthin) and two diesters (zeaxanthin and lutein) were chosen. Egg yolk phosphatidylcholine liposomes served as the membrane model. We measured the sizes of the liposomes by photon correlation spectroscopy. The incorporation yields were determined spectrophotometrically. From liposomes simultaneously doped with the fluorescent dye Laurdan, fluidity changes of the liposomes were obtained. In summary, the results indicate that the carotenoid esters: (i) get incorporated, but at a lower yield than their corresponding free carotenoids, (ii) also increase the membrane rigidity as do the free carotenoids, and (iii) increase the liposome sizes significantly, but after extrusion through an 0.1 µm filter the sizes resemble with the exception of the liposomes incorporated with lutein diesters, they remain bigger indicating an elastic property due to two different accessible locations in the membrane