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Start Over Coverage 183-189

1. Myxozoans infecting the sharptooth catfish, Clarias gariepinus in the Okavango River and Delta, Botswana, including descriptions of two new species, Henneguya samochimensis sp. n. and Myxobolus gariepinus sp. n.

Creator:
Reed, Cecilé C., Basson, Linda, and Van As, Liesl L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Myxozoa, Myxobolus, Henneguya, new species, taxonomy, Clarias, and Botswana
Language:
English
Description:
During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Photosynthetic electron transport, photophosphorylation, and antioxidants in two ecotypes of reed (Phragmites communis Trin.) from different habitats

Creator:
Zhu, X. Y., Chen, G. C., and Zhang, C. L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
antioxidant, ascorbate peroxidase, chloroplast, cyclic electron flow, Mg2+-ATPase, natural drought, photosystem 1 and 2 activities, stomatal resistance, superoxide dismutase, and transpiration rate
Language:
Multiple languages
Description:
We compared chloroplast photochemical properties and activities of some chloroplast-localised enzymes in two ecotypes of Phragmites communis, swamp reed (SR, C3-like) and dune reed (DR, C4-like) plants growing in the desert region of north-west China. Electron transport rates of whole electron transport chain and photosystem (PS) 2 were remarkably lower in DR chloroplasts. However, the electron transport rate for PS1 in DR chloroplasts was more than 90 % of the activity similar in the SR chloroplasts. Activities of Mg2+-ATPase and cyclic and non-cyclic photophosphorylations were higher in DR chloroplasts than in the SR ones. The activities of chloroplast superoxide dismutase (SOD) and ascorbate peroxidase (APX), both localised at or near the PS1 complex and serving to scavenge active oxygen around PS1, and the content of ascorbic acid, a special substrate of APX in chloroplast, were all higher in DR chloroplasts. Hence reed, a hydrophytic plant, when subjected to intense selection pressure in dune habitat, elevates its cyclic electron flow around PS1. In consequence, it provides extra ATP required by C4 photosynthesis. Combined high activities of active oxygen scavenging components in DR chloroplasts might improve protection of photosynthetic apparatus, especially PS1, from the damage of reactive oxygen species. This offers new explanation of photosynthetic performance of plant adaptation to long-term natural drought habitat, which is different from those, subjected to the short-term stress treatment or even to the artificial field drought. and X. Y. Zhu, G. C. Chen, C. L. Zhang.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public