摘要:

ABSTRACTBiological factors have been found which can cause variable toxicity of colony and clonal isolates ofAnabaena flos‐aquae(Lyngb.) de Bréb. when cultured in the laboratory. These factors help to explain some of the variable toxicity of and animal susceptibility toA. flos‐aquaeblooms in nature. Two bacteria in the Enterobacteriaceae isolated from a toxic waterbloom, depressed toxin production in selected bacteria‐free toxic clones ofA. flos‐aquae.These toxin‐depressing bacteria decreased culture toxicity 3‐fold from 80 to 240 mg/kg (intra‐peritoneal in male mice). Many colony isolates from a toxic bloom had minimum lethal dosages (LDmin) greater than 240 mg/kg. This was because they were composed of mixtures of toxic and nontoxic filaments. The oral LDminof the toxin fromA. flos‐aquaeclonal isolate NRC‐44‐1 varied significantly for 6 different animal species. Using these oral LDminit is estimated that a surface‐concentrated bloom of toxicA. flos‐aquae,having a biomass density of 20 mg/ml dry weight, would cause death of ducks or calves when 20 ml/kg was consumed whereas a monogastric animal such as a ra

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02894.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTMultinucleate cells ofCoelastrumundergo precisely directed cytokinesis, guided by phycoplast microtubules, to form a number of uninucleate daughter cells which subsequently adhere to form characteristically patterned aggregates. As there is no movement of the daughter cells relative to one another before their adhesion, the disposition of cells in daughter colonies reflects the pattern of cytokinesis of parent cells. Centrioles lie at the poles of the mitotic nuclei which are partially enclosed by a perinuclear envelope of endoplasmic reticulum. The centrioles disappear at the time of cytokinesis of the parental cell and apparently reformde novoonce the daughter cells have acquired a cell wall following their adhesion. The trilaminar layer of cell wall, often termed the pectic layer, does not stain with ruthenium red and resists acetolysis suggesting that it contains sporopollenin rather than pectin.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02895.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTAlgae were sampled along temperature gradients of 30 thermal springs in Colorado, Idaho, Montana and Wyoming. From a maximum temperature of 74.5 C downstream, to ca. 62 C, the diversity of the algae was limited to the various forms ofSynechococcus lividusCopeland; from ca. 62 to 40–45 C it coexisted with other algae. WhenS. lividuswas in direct sunlight the mean length was greatest at the highest temperatures of its existence, becoming shorter as the water cooled; the mean reduction in length was 0.132 μm for each 1 C reduction in temperature. The cells in a shaded stream did not exhibit the reduction in size with reduced temperature, but remained about the same length from 73 C downstream to 45 C. The longer cells from the highest temperatures of their existence in any stream could not become established in the cooler water downstream, so the range of cell lengths (diversity) became less as the water cooled. Unknown dissolved substance(s) depressed the upper temperature limit in two streams and had a reverse effect on the expected length–temperature relationship; the shortest cells were at the higher temperatures. Generally, total dissolved substances had a positive effect on the length; the longest cells were in the water with the highest total dissolved solids (TDS) at the upper temperature limits of 70–74.5 C. In the temperature range of 55–60 C the higher TDS were not as effective in developing long

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02896.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe in vitro temperature inactivation of the electron transport system (ETS) activity was measured for 11 phytoplankton species. The average inactivation temperature is between 18–23 C, but exceptions with inactivation temperatures as high as 43 C were noted for a tide pool phytoplankton,Dunaliella tertiolectaButcher. Despite differences in temperatures at which the ETS activity begins to decrease, experimental values for the energies of activation (E) of electron transport are very similar and average ca. 12 kcal/mol. The results show the necessity of applying temperature corrections to in vitro ETS activity measurements when oceanic in situ oxygen consumption is computed from ETS activity measurements. The progress of thermal inactivation of the ETS activity in phytoplankton species studied yields biphasic curves. The biphasic nature of the curves is expressed when using both relatively high and low temperature of inactivation and in more or less heat sensitive species. These curves are described in terms of microsomal and mitochondrial substrate dependence. Based on the obtained temperature response of the ETS activity, the adaption of phytoplankton species to growth temperature is discusse

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02897.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTTransmission electron microscopy of the iridescent algaeIridaea flaccida(S&G) Silva,Iridaea cordata(Turn.) Bory var.cordataandI. cordatavar.splendens(S&G) Abbott reveals a multilaminated cuticle covering the thallus. Experimental results show the cuticle: a) can be isolated intact by mechanical scraping or NaOH treatment; b) is iridescent by itself and the denuded thallus is not; and, c) is isolated without any subtending polysaccharide layer, cell walls, or cells. This cuticle acts as a thin layer producing the constructive and destructive light interference which is seen as iridescence. It is formed of alternating electron opaque and translucent layers with a total thickness of 0.5–1.6 μm. Analysis of mechanically isolated cuticle shows that it is composed of protein (50%), carbohydrate (ca. 40%), inorganic salts (5%) and some fatty acids (less than 1.0%). The electron opaque layers may correspond to protein‐rich regions and the electron translucent ones to regions rich in carbohydrates. The cuticle does not appear to affect photosynthesis or respiration, but rather, may protect the alga from physical factors such as desiccation and from predator injury. It is likely that the iridescence in other foliaceous red algae is caused by a similar struc

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02898.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTTotal protein was determined for cells ofAphanothece halophyticaFremy harvested during early log, mid‐log and linear growth phases in media containing 1, 2, and 3 M NaCl. Cells grown in medium containing 1 M NaCl showed a progressive increase in protein content up to a maximum of 76% of dry weight (linear phase). Total protein also increased in cells grown in 2 M NaCl. medium (56.5–72.0%). Cells grown in 3 M NaCl medium showed a progressive decrease in total protein (59.9–43%). Although amounts of protein varied, the percentages of the respective amino acids of hydrolyzed bulk protein were consistent to within 1% for linear phase cells grown in 1, 2, and 3 M NaCl cultures. Percentages of acidic amino acids were 2.3–2.6 times greater than those of the basic amino acids. The amino acid composition of phycocyanin was similar to that of bulk protein. Free amino acids varied with both age of the culture and the concentration of NaCl. The high quantity and quality of the protein observed suggest thatA. halophyticamight be a useful food o

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02899.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTAn isolate ofUlva lactucaL. was brought into axenic culture in both defined synthetic medium and enriched seawater. Haploid clones were established and followed through several generations in both media. Plants possessing distromatic, partially distromatic or completely tubular blades in cross sections, as well as individuals that were completely distromatic in one area of the blade and tubular in another all developed from the same swarmer population. Variations in basal area morphology also occurred. Progeny from swarmers of any of these morphological types showed a similar mixture of morphological variation, indicating non‐mutational variability in phenotypic expression of the blade and basal areas. A mechanism by which such variation may occur without mutation is discusse

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02900.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02901.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe foliose red algaGigartina papillata(C. Ag.) J. Ag. was studied in culture to determine its life history and possible relationship to the life history ofPetrocelis middendorffii(Ruprecht) Kjellman. Carpospores cultured from individual female plants gave rise to either crustosePetrocelis‐like plants that reproduced by tetraspores, or to another generation of foliose female (cystocarpic) plants that reproduced by carpospores. Apices cultured from blades of individual field‐collected female plants produced either papillae with many procarps that developed cystocarps only when crossed with male plants, or papillae with few procarps that produced cystocarps in the absence of male plants. The results are interpreted to demonstrate that two types of life history occur inG. papillata:one, a sexual life history involving a crustose tetrasporophyte; the other, a possibly apomictic life history involving only cystocarpic plants. Hybridization experiments demonstrated, thatG. papillatais interfertile withGigartina‐phase gametophytes cultured from tetraspores ofP. middendorffii.Sexual plants of G.papillataare postulated to represent the naturally‐occurring gametophyte ofP. middendorffiiin California. The possible relationships of the sexual and apomictic plants ofG. papillataare di

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02902.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02903.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY