摘要:

ABSTRACTBy immuno‐electron microscopy it was shown that phycoerythrin is located on the outer surface of the phycobilisome and allophycocyanin is on the inside near the photosynthetic membrane in the red algaPorphyridium purpureum(Bory) Drew&Ross(P. cruentum).These findings are consistent with the idea that the phycobilisome junctions as a light harvesting antenna and energy sink, which directs the energy to chlorophyll in the photosynthetic membrane. A technique was devised in which unfixed phycobilisomes, attached to thylakoid vesicles, were separately reacted with three monospecific antisera (to B‐phycoerythrin, R‐phycocyanin and allophycocyanin) and the reaction products were secondarily marked by reaction with ferritin‐conjugated goat‐antirabbit gamma globulin fraction. This was subsequently followed by glutaraldehyde fixation and staining with phosphotungstic acid. The entire procedure was carried out on an electron microscope grid. The results confirm the previously proposed phycobilisome structu

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02912.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.tb02913.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT14C‐amino acids were supplied toPlatymonas subcordiformis(Wille) Hazen and the incorporation of radioactivity into protein and other compounds was followed. Alanine was rapidly metabolized by both N‐limited and N‐sufficient cells. Arginine and lysine were metabolized rapidly by N‐limited cells, but were sequestered from metabolism in N‐sufficient cells. This suggests the existence of two functionally distinct pools; a “metabolic” pool that is rapidly metabolized and preferentially used for incorporation into protein, and a “storage” pool rich in basic amino acids that is sequestere

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02914.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTInitial Cu++sorption byCyclotella meneghinianaKütz. (Cu++‐sensitive) andChlamydomonas reinhardtiiDangeard (Cu++‐resistant) was rapid in the first 5 min of Cu++incubation with little sorption after 2 h. On a cell to cell basis,Cyclotellasorbed ca. five times more Cu++from the medium thanChlamydomonas.In MBL medium with EDTACyclotellaandChlamydomonascells sorbed 21.0 and 4.41 nM Cu++/106cells respectively in 6 h with 0.3 mg Cu++/l in the medium. Proportionally similar quantities of Cu++were sorbed when the cells were Cu++incubated in MBL + citrate or filtered lake water. Cleaned cell walls ofCyclotellasorbed little Cu++(1.7 nM/106cells) as compared to living cells (17.5 nM Cu++/106cells) in 3 h. Therefore, in livingCyclotellamost of the Cu++taken up must be absorbed by the protoplasm or perhaps by the organic layer surrounding the silica wall. Cleaned cell walls ofChlamydomonassorbed 3.5 nM Cu++/106cells and livingChlamydomonascells sorbed 2.6 nM Cu++/106cells. This indicates that most of the Cu++sorbed byChlamydomonascells remained bound to the cell wall and probably did not readily enter into the protoplasm: When placed in Cu++free medium after Cu++incubation,CyclotellaandChlamydomonascells released 46 and 59% respectively of the Cu++so

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02915.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe effects ofBdellovibrio bacteriovorus(Stolp&Starr) culture supernatants onPhormidium luridumvar.olivaceaBoresch andSynechococcussp. were examined by transmission electron microscopy. Both normal (nonheat‐treated) and heat‐treated bdellovibrio supernatant caused the formation of intrathylakoidal vesicles inP. luridumin 24–48 h. This vesiculation increased until 96–129 h when theP. luridumshowed loss of the mucopeptide layer in the cell envelope and subsequently lysed. Similar treatment ofSynechococcussp. with the bdellovibrio supernatants showed a different ultrastructural pattern with the apparent dissolution of many of the photosynthetic membranes in the bluegreen cells. Myelin‐like membranous configurations were seen in some of these treated cells. The results suggest that an autolytic mechanism inP. luridumandSynechococcussp. is stimulated by the bdellovibrio s

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02916.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTCultures ofIsochrysis galbanaParks andPhaeodactylum tricornutumBohlin were grown in iron‐limited chemostats. With increasing iron deficiency, photosynthetic rate per cell and assimilation number decreased. The pattern of photosynthesis was also altered; in Fe deficient cells the proportion of14C fixed in glycine and serine decreased with an accompanying increase into alanine after 3 min assimilation. Although there was no significant effect of Fe deficiency on the proportion of14C incorporated into total amino acids and amides, the percentage of total14C fixed in protein increased with increasing Fe deficiency. Cellular levels of chlorophylla, carotenoids, cytochromes and protein also decreased with increasing Fe deficiency. However, the reduction in chlorophylla/cell was not as great as that of cytochrorne f1and Fe deficient cells therefore showed a marked increase in chlorophyll a:cytochrorne f1rati

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02917.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTLaboratory studies on blade growth inAlaria esculenta(L.) Grev. showed 3 periods of rapid blade elongation during the year: October–November, February–April and late June. The first two periods are characteristic of many Laminariales; the unique June peak may reflect local nutrient conditions. While the distal blade functions as a source, supplying organic matter to the blade meristem, the stipe can be a source during periods of rapid growth or a sink during late summer when blade growth is slow. Maximum enhancement of elongation rate of blade meristems was observed in 40–50 cm blades; longer blades showed no further increase in growth rate. This blade length‐growth promotion relationship may be independent of seasonal variations in meristematic activity.14C tracer experiments suggested that separate growth promotion effects by distal blade, sporophylls and stipe were not additive in the intact thallus. The preferential source of assimilate for blade meristem growth was the distal blade. Secondary sources: sporophylls, which were activated following excision of the primary source; and stipe, which began to translocate assimilate when both sources were removed. The role of secondary sources in nature is discussed. Profiles of radioactivity in alcohol‐soluble organic matter in blades are evaluated in relation to tracer profiles in higher plants and mechanisms of tran

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02918.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe unusual morphology of the coccoid, neustonic algaNautococcus mammilatusKorschikov prompted its study with the electron microscope. Ultrastructural features including a fibrous cell wall with definite periodicity and an external tomentum were observed. These and other features of the alga are compared with those of related, species, and the use of cell wall characteristics in taxonomy is discussed.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02919.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.tb00588.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTYoung zygotes from crosses ofChlamydomonas reinhardtiiDang. mutant and wild‐type strains were incubated, in the presence or absence of light and/or nitrogen to determine whether continuation of conditions inducing gamete formation permits zygospore formation without loss of viability. Different culture media, continuous illumination vs. dark incubation and various durations of the maturation period were tested, for effect on zygospore germination efficiency, zygospore “burst size” and zoospore viability. Following either the routine maturation procedure of dark incubation on standard minimal medium, or following a new procedure of incubation under continuous illumination on N‐free medium, zygospore formation can be ensured and high germination efficiencies obtained within 3 days after mating. Tetrad analysis indicates meiosis occurs normally whether zygotes have been matured in the presence or absence of light or nitrogen. Preliminary data suggest an effect of increased maturation time on the transmission of cytoplasmic genes, if a N‐free continuous illumination maturation protocol is followed. Two experimental approaches for the maturation ofC. reinhardtiizygotes are suggested and advantages of each are

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1977.tb02920.x

出版商:Blackwell Science Inc    

年代:1977

数据来源: WILEY