Katia Georgieva

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This is the first ultrastructural study of the spermiogenesis and the mature spermatozoon of a cyclophyllidean cestode of the family Gryporhynchidae. The spermiogenesis of Valipora mutabilis begins with the formation of a differentiation zone delimited by arching membranes and containing two centrioles. One of the centrioles develops an axoneme that grows(More)
Ultrastructural characters of spermiogenesis and mature spermatozoon of Triaenorhina rectangula (Fuhrmann, 1908) are examined by transmission electron microscopy. Spermiogenesis follows the Bâ and Marchand's Type III spermiogenesis of cestodes. The process begins with the formation of a differentiation zone containing two centrioles and a cytoplasmic(More)
The response of tobacco plants (Nicotiana tabacum L.)--non-transformed and transformed with a metallothionein gene MThis from Silene vulgaris L.--to increase cadmium supply in the nutrient solution was compared. The transgenic plants accumulated significantly more Cd both in the roots and the leaves. Visual toxicity symptoms and disturbance in water balance(More)
In the present work it is demonstrated that Salicylic acid (SA) and Methyl Jasmonate (MeJA) provided protection of photosynthesis (A) against paraquat (Pq) stress and diminished the oxidative damage caused by Pq. Barley seedlings (12 d old) were supplied with 500 µM SA, 23 µM MeJA or 10 µM Pq via the transpiration stream and kept in the dark for 24 h. They(More)
A review is made of recent publications concerning the mechanisms of damage and acclimation of the photosynthetic apparatus due to high temperature. Under stress the organisms undergo first of all destabilisation followed by normalisation and stability, when limit of tolerance are not exceeded and the adaptive capacity is not overtaxed. The influence of(More)
In the present study we have focused on the heat shock protein-70 (HSP-70) response of spermatogenic and somatic cells in testis of endurance trained rats. As material, adult male Wistar rats distributed into two groups were used: group 1 of control animals and group 2 of endurance trained rats (treadmill-type exercise for eight weeks). Using an ABC(More)
The ultrastructure of the contact surfaces (integument and intestinal wall) of the nematode Passalurus ambiguus has been studied. The integument is composed according to the scheme common for all nematodes and includes a cuticle, hypodermis and a muscular layer. The specificity is with regard to the epicuticle, the different number of the cuticular(More)
A new one-step incubation method using cationic gold colloid was applied to reveal anionic moieties in rat colonic mucosa. Gold particles were detected in all cellular nuclei, basement membranes, mast cell granules and collagen fibres, while the luminal surfaces of all vascular endothelial cells were devoid of gold label. Application of the method for(More)
The effect of protein phosphorylation on the functional activity of PS2 under control and photoinhibitory conditions has been investigated. The time course of phosphorylated and non-phosphorylated PS2 enriched membranes (BBYs) has been monitored by chlorophyll fluorescence using a PAM fluorimeter. The results show that photochemical activity did not change(More)
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