Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.

• MeSH
• bílkoviny řas metabolismus   MeSH
• buněčná membrána enzymologie   MeSH
• Chlorella fyziologie   účinky záření   MeSH
• enzymy metabolismus   MeSH
• oxid dusnatý fyziologie   MeSH
• systémy druhého messengeru * MeSH
• ultrafialové záření * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bílkoviny řas MeSH
• enzymy MeSH
• oxid dusnatý MeSH

This review surveys whatever little is known on the influence of different environmental factors like light, temperature, nutrients, chemicals (such as plant hormones, vitamins, etc.), pH of the medium, biotic factors (such as algal extracellular substances, algal concentration, bacterial extracellular products, animal grazing and animal extracellular products), water movement, water stress, antibiotics, UV light, X-rays, gamma-rays, and pollution on the spore germination in algae. The work done on the dormancy of algal spores and on the role of vegetative cells in tolerating environmental stress is also incorporated.

• MeSH
• ekosystém * MeSH
• Eukaryota fyziologie   účinky záření   MeSH
• spory fyziologie   účinky záření   MeSH
• viabilita buněk MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Lyngbya major (a wall alga), survived throughout year, maximally to >80 % at atmospheric temperature (AT) of 17-36 degrees C and relative humidity (RH) 60-100 % in rainy and spring seasons, but the survival was 43-64 % in winter when AT decreased to 5 degrees C and RH was 65-98 %, and 15-23 % in summer when AT reached 48 degrees C and RH was 23-60 %. All soil algae (Lyngbya birgei, Aphanothece pallida, Gloeocapsa atrata, Oscillatoria subbrevis, O. animalis) survived >90 % in rainy season when soil moisture content (SMC) was 89-100 %. Lowering of SMC to a minimum of 55 % in spring and 39 % in winter led L. birgei, O. subbrevis and O. animalis to survive from 75, 66, and 65 %, respectively, in spring and 12, 14, and 20 % in winter, and A. pallida and G. atrata not at all in both seasons. All soil algae did not survive in summer when SMC was 12-30 %. Myxosarcina burmensis survived only in rainy and spring seasons when pond water temperature (PWT) was 19-25 degrees C and 18-26 degrees C, respectively, and not in winter and summer when PWT was 2-14 degrees C and 25-36 degrees C, respectively. L. major and A. pallida survived almost equally well under both submerged and air-exposed conditions for 15 d but less if submerged for more time than air-exposed on moist soil surface, while L. birgei, G. atrata, O. subbrevis, and O. animalis survived submergence in liquid medium better and longer than air-exposure on moist soil surface. Pond alga M. burmensis survived submergence better than air-exposure, true to its aquatic habitat. All algae survived less and died without forming any resistant cells when exposed to physical and physiological water stress (imposed by growing them on highly agarized media or in salinized liquid media), light stress (at 0, 2 and 10 micromol m(-2) s(-1) light intensity) or following UV shock (0.96-3.84 kJ/m(2)). A. pallida and G. atrata cells did not divide on 8 % agarized solid media, in > or =0.3 mol/L salinized liquid media, and in darkness. The presence of sheath over L. major and L. birgei filament cells and mucilage cover over A. pallida and G. atrata cells protect them against physical desiccation to some extent but not against UV shock.

• MeSH
• ekosystém MeSH
• fyziologický stres MeSH
• mikrobiální viabilita * účinky záření   MeSH
• půda MeSH
• půdní mikrobiologie * MeSH
• roční období MeSH
• sinice fyziologie   účinky záření   MeSH
• teplota MeSH
• ultrafialové záření MeSH
• vlhkost MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• půda MeSH

The effect of temperature, light and nutrient composition on morphological traits was determined in seven nostocacean cyanobacteria (Anabaena planctonica, A. sphaerica var. conoidea, A. spiroides, Aphanizomenon gracile, Nostoc sp., Scytonema sp., and Tolypothrix sp.). Their morphological variability was high but only some of the features showed changes reflecting varied growth conditions. The frequency of heterocyst occurrence decreased with increasing nitrogen concentration. Within the range studied, the effect of temperature on heterocyst frequency of Tolypothrix sp. and planktonic Anabaena strains could be fitted by a normal curve with a clear optimum while linear correlation was found in Aphanizomenon gracile. T-and S-type branching was observed in both Scytonema sp. and Tolypothrix sp. strains. T-type branching was found to be markedly dependent on nitrogen concentration. The abundance of necridic cells of Tolypothrix sp. increased linearly with temperature and light intensity. Regularity of trichome coiling of A. spiroides depended on culture medium, suggesting that nutrient composition may be the main controlling factor. In contrast, the effect of the experimental conditions on the dimensions of vegetative cells and heterocysts was weak. Their variability was markedly higher within each experimental treatment than between treatments.

• MeSH
• dusík metabolismus   MeSH
• kultivační média metabolismus   MeSH
• půdní mikrobiologie MeSH
• sinice cytologie   růst a vývoj   metabolismus   účinky záření   MeSH
• světlo MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• dusík MeSH
• kultivační média MeSH

Batch cultures of Chlorella vulgaris and C. variegata reproducing about twice every 5 d within 0-15 d had vegetative cells and autospore mother cells in the ratio of about 19 : 1. Continuous slow or negligible and/or no growth in > 15-d-old control cultures or in young cultures supplied with the antibiotics streptomycin, penicillin, amoxycillin (10-1000 ppm) or tetracycline (10, 100 ppm), and pesticides carbofuran, gammaxine, moticop or iralon (1-100 ppm) was due to slow autospore mother cells dehiscence (leading to an increase in their percentage); while negligible and/or no growth of both algal species in sewage water (100, 25%), detergent (0.1-1%), petrol or kerosene (5-20 %), benzene, toluene or phenol (5, 10%) and pesticides rogor or endosulfan (1, 10 ppm) was due to vegetative cells failure to differentiate into auto-spore mother cells (leading to decreased/zero autospore mother cells percentage) and/or rapid death of all cells. C. variegata was equally or slightly more sensitive to different chemical stress than C. vulgaris.

• MeSH
• antibakteriální látky farmakologie   MeSH
• Chlorella vulgaris účinky léků   růst a vývoj   ultrastruktura   MeSH
• detergenty farmakologie   MeSH
• odpadní vody mikrobiologie   MeSH
• pesticidy farmakologie   MeSH
• ropa MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Indie MeSH
• Názvy látek
• antibakteriální látky MeSH
• detergenty MeSH
• odpadní vody MeSH
• pesticidy MeSH
• ropa MeSH

Suitable morphological characteristics for identification of zygnematalean algae were determined using a combination of classical light microscopy (LM) techniques, fluorescence microscopy (with blue and green excitation), scanning electron microscopy (SEM) and specialized culture methods. Characteristics of spore germination, growth and reproduction under culture conditions identified Zygnema chalybeo-spermum in a mixture of zygnematalean spores collected from a small fishpond in Czechia. Reproduction in general, particularly aplanospore formation and lateral conjugation was more frequent and occurred earlier in a nutrient poor medium than in a nutrient rich medium, where vegetative growth was more vigorous. Variability in spore size was wide and influenced by the origin (sexual and/or asexual) of the spores. Asexual spores, particularly partenospores were rounded and significantly smaller than sexual ones. Thus spore morphology alone (size and shape) is not a particularly helpful characteristic for species identification. The mesospore of mature spores contained lipids and a sporopolenin-like material (algaenan), which showed green autofluorescence with blue excitation. The mesospore ornamentation, the only characteristic found that is suitable for identification purposes, can be observed easily in LM and SEM after exospore removal by KOH treatment. Detailed LM and SEM observations of the zygospores of all Zygnema species thus could provide basic data necessary for the preparation of an atlas and key for species identification which, after completion with molecular methods, brings clarification into the genetic relationships between morphospecies.

• MeSH
• druhová specificita MeSH
• Eukaryota klasifikace   izolace a purifikace   fyziologie   MeSH
• kultivační média MeSH
• mikrobiologie vody MeSH
• mikroskopie MeSH
• sladká voda mikrobiologie   MeSH
• spory hub izolace a purifikace   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• kultivační média MeSH

Navicula grimmei and Nitzschia palea occurring almost equally in a mixed population on department moist garden soil surface when maintained in fresh supernatant (of soil-water medium) at pH 7.0, temperature of 26 +/- 1 degree C and under continuous light (intensity of approximately equal to 30 micromol m(-2) s(-1)) in a culture chamber exhibited a similar cell survival period (of 28 d) and percentage (at the beginning 100 % and mid of survival period 65 %) and stop gliding 11 d prior to cell death (with gliding speed reduced in both from 204-330 microm/min at the beginning to 82.5-99 microm/min at the mid of gliding period) irrespective of their size differences. However, a sharp fall in the cell gliding period, gliding cell percentage and speed occurred at various levels (different from cell survival period and percentage) in both diatoms in a similar extent under water stress (2, 4 and 6 % agarized supernatant, liquid supernatant with 0.2-1.0 mol/L NaCl, blot-dryness of cells for 5-15 min), pH extreme of liquid supernatant (< or =5.0, > or =9.0), temperature extremes in liquid supernatant (< or =15, > or =40 degrees C), UV exposure (0.96-5.76 kJ/m2), lack of all nutrients from the medium (double distilled water), darkness or low light intensities (2 and 10 micromol m(-2) s(-1)), presence of 'heavy' metals (Ni, Cu, Zn, Co, Fe, Hg; 1-200 ppm), organic substances in liquid supernatant (DDT, captan, urea, 2,4-D, 100-2000 ppm; thiourea, 50-1000 ppm). N. palea sway (turn around at either ends) or not only when gliding but independent of cell gliding speed, which decreased continuously under all conditions.

• MeSH
• kokultivační techniky MeSH
• koncentrace vodíkových iontů MeSH
• organické látky MeSH
• pohyb MeSH
• rozsivky fyziologie   účinky záření   MeSH
• teplota MeSH
• těžké kovy MeSH
• ultrafialové záření * MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• organické látky MeSH
• těžké kovy MeSH
• voda MeSH

Pithophora oedogonia and Cladophora glomerata survived lowest 60 and 58%, respectively, in June when the pond diurnal water temperature (PDWT) increased to a maximum of 28 degrees C. The lowering of PDWT only by 1 degrees C in July improved survivability of both algae to their almost maximum level of 100 and 96%, respectively. Further lowering of PDWT to 17-22 degrees C in November initiated akinete formation in P. oedogonia. The process of akinete initiation, maturation and germination continued till April when PDWT increased to 20-24 degrees C, but not beyond that in May when PDWT was 21-26 degrees C. By this time, probably all akinetes have germinated in situ, and the alga was entirely vegetative. P. oedogonia population is not synchronous in nature, since during the 5-6-month reproductive season, some filaments were in active vegetative stage, some had akinete initiation, some had completed akinete formation, and some had akinetes germinating. C. glomerata grew dense vegetative in November and initiated (zoo)sporangial primordia formation (to some extent) in February (when PDWT was lowest, viz. 10-14 degrees C) till April. Meanwhile, no (zoo)-sporangial primordia either produced any zoospore or germinated into a germ tube; and all released their cytoplasmic content and died (along with some vegetative cells) with an increase in PDWT to 21-26 degrees C in May. Vaucheria geminata vegetative patches appeared on the soil surface, 2nd week of January by lowering of atmospheric diurnal temperature (ADT) to 9-16 degrees C in the 1st week. The alga started sexual reproduction by the 2nd week of March (when ADT increased to 20-23 degrees C) and completed the process of reproduction by the 1st week of April (when ADT increased to 24-26 degrees C) and died thereafter. P. oedogonia, C. glomerata and V. geminata survived better and longer in submerged conditions than air-exposed (which was true for P. oedogonia and C. glomerata aquatic habitat and also indicated that the soil alga V. geminata could survive to some extent if submerged in rain water). P. oedogonia formed akinetes and C. glomerata (zoo)sporangial primordia only in submerged condition and not when air-exposed on moist soil surface. V. geminata did not complete the life cycle both under submerged and air-exposed conditions. Vegetative survival in P. oedogonia, C. glomerata, V. geminata, Aphanothece pallida, Gloeocapsa atrata, Scytonema millei, Myxosarcina burmensis, Phormidium bohneri, Oscillatoria animalis, O. subbrevis, Lyngbya birgei, L. major, Microcoleus chthonoplastes and Rhizoclonium crassipellitum, reproduction in P. oedogonia, C. glomerata and V. geminata, cell division in A. pallida and G. atrata, heterocyst and false branch formation in S. millei, all, were adversely affected at approximately 28.5 degrees C for t12 h at light intensity of approximately 160 micromol m(-2) s(-1); high intensity does not ameliorate high temperature damage to any algae. The presence of liquid water, than its absence, outside the different algae moderated the severity of heat to some extent but not when the heat was severe.

• MeSH
• Eukaryota cytologie   růst a vývoj   MeSH
• mikrobiální viabilita * MeSH
• mikroskopie MeSH
• půdní mikrobiologie * MeSH
• sladká voda mikrobiologie   MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH