Journal of Phycology
1529-8817
0022-3646
Anh Quốc
Cơ quản chủ quản: Wiley-Blackwell Publishing Ltd , WILEY
Lĩnh vực:
Plant ScienceAquatic Science
Phân tích ảnh hưởng
Thông tin về tạp chí
The Journal of Phycology was founded in 1965 by the Phycological Society of America. The Journal is a leading international journal and publishes research from all over the world. All aspects of basic and applied research on algae are included to provide a common medium for the ecologist, physiologist, cell biologist, molecular biologist, morphologist, oceanographer, acquaculturist, systematist, geneticist, and biochemist. The Journal also welcomes research that emphasizes algal interactions with other organisms and the roles of algae as components of natural ecosystems.
Các bài báo tiêu biểu
EXPLORING THE NATURAL ROLE OF MICROCYSTINS—A REVIEW OF EFFECTS ON PHOTOAUTOTROPHIC ORGANISMS<sup>1</sup> Cyanobacterial blooms and the production of cyanotoxins represent a serious global problem. Although the effects of a group of important cyanotoxins, microcystins (MCs), have been studied intensively in various organisms, little is known about the natural functions of these cyclic heptapeptides. MCs may have allelopathic effects. This paper summarizes the information from the studies that have investigated the effects of MCs on photoautotrophs in vitro and in vivo . Interactions with terrestrial plants, macrophytes, macroalgae, and planktonic microalgae are reported in detail with respect to the ecological relevancy of experimental conditions related to allelopathy. Our review shows that only a limited number of studies described harmful effects of MCs at concentrations that are typical for the environment. Consequently, the ability of MCs to act as general allelopathic compounds against photoautotrophs seems unlikely. However, further research is needed for definitive confirmation or rejection of the allelopathic hypothesis as well as, an explanation of the crucial question of MC function in the context of new information from evolutionary and molecular biology.
Tập 42 Số 1 - Trang 9-20 - 2006
AN OUTBREAK OF DOMOIC ACID POISONING ATTRIBUTED TO THE PENNATE DIATOM <i>PSEUDONITZSCHIA AUSTRALIS</i><sup>1</sup> ABSTRACT A bloom of the pennate diatom Pseudonitzschia australis Frenguelli (= Nitzschia pseudoseriata Hasle) occurring in Monterey Bay, California, in early September 1991 coincided with an episode of mortality in brown pelicans (Pelicanus occidentalis) and Brandt's cormorants (Phalacrocorax penicillatus). High levels of domoic acid (DA), the amnesic shellfish poisoning toxin, were recorded in the plankton samples. Furthermore, high levels of DA, as well as numerous remnants of P. australis frustules, were found in the stomach contents of affected birds and in the visceral contents of local anchovies, a principal food source of seabirds. This is the first confirmed report of DA poisoning since the original 1987 episode in Atlantic Canada caused by Nitzschia pungens Grunow forma multiseries Hasle. It suggests another species of planktonic pennate diatom is capable of producing DA and that herbivorous finfish can act as vectors for this toxin.
Tập 28 Số 4 - Trang 439-442 - 1992
EVIDENCE A PHOTOPROTECTIVE FOR SECONDARY CAROTENOIDS OF SNOW ALGAE<sup>1</sup> ABSTRACT Snow algae occupy a unique habitat in high altitude and polar environments. These algae are often subject to extremes in nutrient availability, acidity, solar irradiance, desiccation, and ambient temperature. This report documents the accumulation of secondary carotenoids by snow algae in response to the availability of nitrogenous nutrients. Unusually large accumulations of astaxanthin esters in extra‐chloroplastic lipid globules produce the characteristics red pigmentation typical of some snow algae (e.g. Chlamydomonas nivalis (Bauer) Wille). Consequently these compounds greatly reduce the amount of light available for absorption by the light‐harvesting pigment‐protein complexes, thus potentially limiting photoinhibition and photodamage caused by intense solar radiation. The esterification of astaxnthin with fatty acids represents a possible mechanism by which this chromophore can be concentrated within cytoplasmic globules to maximize its photoprotective efficiency.
Tập 29 Số 4 - Trang 427-434 - 1993
OCEAN CLIMATE CHANGE, PHYTOPLANKTON COMMUNITY RESPONSES, AND HARMFUL ALGAL BLOOMS: A FORMIDABLE PREDICTIVE CHALLENGE
Tập 46 Số 2 - Trang 220-235 - 2010
EVOLUTION OF MICROALGAE IN HIGHLY STRESSING ENVIRONMENTS: AN EXPERIMENTAL MODEL ANALYZING THE RAPID ADAPTATION OF <i>DICTYOSPHAERIUM CHLORELLOIDES</i> (CHLOROPHYCEAE) FROM SENSITIVITY TO RESISTANCE AGAINST 2,4,6‐TRINITROTOLUENE BY RARE PRESELECTIVE MUTATIONS<sup>1</sup> The increasing rates of global extinction due to human activities necessitate studies of the ability of organisms to adapt to the new environmental conditions resulting from human disturbances. We investigated the evolutionary adaptation of a microalga to sudden environmental change resulting from exposure to novel toxic chemical residues. A laboratory strain of Dictyosphaerium chlorelloides (Naum.) Kom. and Perm. (Chlorophyceae) was exposed to increasing concentrations of the modern contaminant 2,4,6‐trinitrotoluene (TNT). When algal cultures were exposed to 30 mg·L− 1 − 5 mutants per cell division. Isolated resistant mutants exhibited a diminished fitness in the absence of TNT. Moreover, the gross photosynthetic rate of TNT‐resistant mutants was significantly lower than that of wild‐type cells. Competition experiments between resistant mutants and wild‐type cells showed that in small populations, the resistant mutants were driven to extinction. The balance between mutation rate and the rate of selective elimination determines the occurrence of about 36 TNT‐resistant mutants per million cells in each generation. These scarce resistant mutants are the guarantee of potential for adaptation.
Tập 38 Số 6 - Trang 1074-1081 - 2002
OPTICAL MONITORING AND FORECASTING SYSTEMS FOR HARMFUL ALGAL BLOOMS: POSSIBILITY OR PIPE DREAM? Monitoring programs for harmful algal blooms (HABs) are currently reactive and provide little or no means for advance warning. Given this, the development of algal forecasting systems would be of great use because they could guide traditional monitoring programs and provide a proactive means for responding to HABs. Forecasting systems will require near real‐time observational capabilities and hydrodynamic/biological models designed to run in the forecast mode. These observational networks must detect and forecast over ecologically relevant spatial/ temporal scales. One solution is to incorporate a multiplatform optical approach utilizing remote sensing and in situ moored technologies. Recent advances in instrumentation and data‐assimilative modeling may provide the components necessary for building an algal forecasting system. This review will outline the utility and hurdles of optical approaches in HAB detection and monitoring. In all the approaches, the desired HAB information must be isolated and extracted from the measured bulk optical signals. Examples of strengths and weaknesses of the current approaches to deconvolve the bulk optical properties are illustrated. After the phytoplankton signal has been isolated, species‐recognition algorithms will be required, and we demonstrate one approach developed for Gymnodinium breve Davis. Pattern‐recognition algorithms will be species‐specific, reflecting the acclimation state of the HAB species of interest.Field data will provide inputs to optically based ecosystem models, which are fused to the observational networks through data‐assimilation methods. Potential model structure and data‐assimilation methods are reviewed.
Tập 35 Số 6 - Trang 1477-1496 - 1999
<i>BOLIDOMONAS</i>: A NEW GENUS WITH TWO SPECIES BELONGING TO A NEW ALGAL CLASS, THE BOLIDOPHYCEAE (HETEROKONTA) A new algal class, the Bolidophyceae (Heterokonta), is described from one genus, Bolidomonas, gen. nov., and two species, Bolidomonas pacifica, sp. nov and Bolidomonas mediterranea, sp. nov., isolated from the equatorial Pacific Ocean and the Mediterranean Sea, respectively. Both species are approximately 1.2 μm in diameter and have two unequal flagella; the longer flagellum bears tubular hairs, whereas the shorter is smooth. The flagellar basal apparatus is restricted to two basal bodies, and there is no transitional helix. Cells are naked, devoid of walls or siliceous structures. The internal cellular organization is simple with a single plastid containing a ring genophore and a girdle lamella, one mitochondrion with tubular cristae, and one Golgi apparatus close to the basal bodies. The Mediterranean and the Pacific species differ in the insertion angle between their flagella and their pattern of swimming, these differences possibly being linked to each other. Analyses of the SSU rDNA gene place the two strains as a sister group to the diatoms. Moreover, pigment analyses confirm this position, as fucoxanthin is found as the major carotenoid in both lineages. These data strongly suggest that the ancestral heterokont that gave rise to the diatom lineage was probably a biflagellated unicell.
Tập 35 Số 2 - Trang 368-381 - 1999
EXTRACTION, ASSAY AND SOME PROPERTIES OF FLORIDOSIDE PHOSPHATE SYNTHASE FROM <i>PORPHYRA PERFORATA</i> (RHODOPHYTA)<sup>1</sup> ABSTRACT A suitable method for extraction of floridoside phosphate synthase (FPS, UDP‐galactose: sn‐3‐glycerol phosphate: 1→2′α‐D‐galactosyl transferase)from Porphyra perforata J. Ag. was developed. Two assay methods for enzyme activity were utilized, one measuring the amount of floridoside formed by using gas‐liquid chromatography, the other measuring the sn‐3‐glycerol phosphate‐dependent formation of UDP; both assays gave similar results. FPS is a soluble protein, and FPS activity in the extract as determined by the amount of product formed in vitro compared well with the in vivo rate of floridoside synthesis (4–7 μMmol product formed·h−1 ·g−1 fresh wt). The rate of product formation in vitro was linear up to 45 min and proportional to protein concentration in the assay mixture. The temperature optimum was 30–35° C. FPS was active over a range of pH values from 7.0–8.5. It was stable in concentrated solutions in the presence of 0.3 M ammonium sulfate, but activity was lost in diluted solution (protein concentration below 0.2 mg·mL−1 ) or below 0.2 M ion strength. The data suggest that FPS may be an oligomeric protein which occurs free in the cytoplasm or loosely bound to a membrane. It may also be a regulatory protein controlling the overall rate of synthesis of floridoside in vivo .
Tập 26 Số 4 - Trang 683-688 - 1990
BIOVOLUME CALCULATION FOR PELAGIC AND BENTHIC MICROALGAE Microalgal biovolume is commonly calculated to assess the relative abundance (as biomass or carbon) of co‐occurring algae varying in shape and/or size. However, a standardized set of equations for biovolume calculations from microscopically measured linear dimensions that includes the entire range of microalgal shapes is not available yet. In comparison with automated methods, the use of microscopical measurements allows high taxonomic resolution, up to the species level, and has fewer sources of error. We present a set of geometric shapes and mathematical equations for calculating biovolumes of >850 pelagic and benthic marine and freshwater microalgal genera. The equations are designed to minimize the effort of microscopic measurement. The similarities and differences between our proposal for standardization and previously published proposals are discussed and recommendations for quality standards given.
Tập 35 Số 2 - Trang 403-424 - 1999
PHOTOADAPTATION AND THE “PACKAGE” EFFECT IN <i>DUNALIELLA TERTIOLECTA</i> (CHLOROPHYCEAE)<sup>1</sup> ABSTRACT In the marine unicellular chlorophyte, Dunaliella tertiolecta Butcher, the spectrally averaged m vivo absorption cross section, normalized to chlorophyll a (so‐called a* values), vary two‐fold in response to changes in growth irradiance. We used a kinetic approach to examine the specific factors which account for these changes in optical properties as cells photoadapt. Using Triton X‐100 to solubilize membranes, we were able to differentiate between “package” effects and pigmentation effects. Our analyses suggest that 43–49% of the variability in a* is due to changes in pigmentation, whereas 51–57% is due to the “package” effect. Further analyses revealed that changes in cell sue did not significantly affect packaging, while thylakoid stacking and the transparency of thylakoid membranes were important factors. Our results suggest that thylakoid membrane protein/lipid ratios change during photoadaptation, and these changes influence the effective rate of light harvesting per unit chlorophyll a .
Tập 25 Số 1 - Trang 70-78 - 1989