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1.
Gracilaria is a potentially valuable source of marine biopolymers such as proteins and polysaccharides. In order to select suitable culture conditions, growth and tolerance of Gracilaria chorda Holmes from Shikoku Island in southwest Japan were investigated under variations of temperature (5–30 ∘C), photon irradiance (20–120 μmol photons m−2 s−1), and photoperiod (12:12 h, 14:10 h light:dark regime) in a unialgal culture. Gracilaria chorda showed wide tolerances for all factors investigated, which is characteristic of eurythermal species. Maximum growth was observed at 18–24 ∘C. The optimum photon irradiance for the algal growth was 60–120 μmol photons m−2s−1. Instead of using ordinary sea salt (NaCl) to prepare artificial seawater, ultra pure salt was adopted. Gracilaria chorda grew faster in artificial seawater made with ultra-pure salt than that made with ordinary sea salt, probably because the former medium was clear, while the latter was milky. Effects of some metal ions on the growth were tested with artificial seawater. Iron ions affected algal growth, but cobalt ions did not. This study enables us to determine suitable culture conditions for G. chorda. A scaled-up 30 l culture of G. chorda under such conditions was successful. 相似文献
2.
Three gracilarioid species, Gracilariopsis bailiniae and Gracilaria tenuistipitata from Vietnam and Gracilaria gracilis from Russia, were studied in order to determine whether Gracilaria gracilis might be a superior species for cultivation in brackish-water ponds for agar production compared with the Vietnamese species.
The effects of different salinity levels on the growth rate and agar production as well as agar properties of three gracilarioid
species were compared in controlled laboratory experiments. Gracilaria tenuistipitata and G. gracilis were tolerant to low salinity (∼10‰), whereas Gp. bailiniae died under these conditions. G. tenuistipitata showed superior growth among the three species examined. Gracilaria gracilis had the highest agar content [36.8–46.6% dry weight (dw)]. Agar yield from Vietnamese gracilarioids did not exceed 30% dw.
Gel strength of native agar from Gracilaria gracilis was two-fold higher that from Vietnamese species (278 g cm−2 vs 130 g cm−2). Alkali pretreatment increased gel strength significantly for Gracilaria gracilis (1.4-fold), and G. tenuistipitata and Gp. bailiniae (2.3-fold) compared with native agar. The results suggest that Gracilaria gracilis may be a suitable species for production of reasonably good quality agar. 相似文献
3.
Franciane Pellizzari Eurico C. Oliveira Nair S. Yokoya 《Journal of applied phycology》2008,20(1):75-82
Gayralia K.L. Vinogr. is a monostromatic green alga of commercial importance in the southern Brazil, and its cultivation is being
considered. This paper reports some basic aspects of the biology of this poorly known genus. Two populations of Gayralia spp., from outer and inner sectors of Paranaguá Bay, showed an asexual life history with a distinct pattern of thallus ontogeny.
In one population (Gayralia sp. 1), zooids developed an expanded monostromatic blade directly, while in the other (Gayralia sp. 2) zooids produced an intermediate saccate stage, before giving rise to a monostromatic blade. Thalli of the two species
differ in size and in cell diameter. The effects of temperature (16–30°C), irradiance (50–100 μmol photons m−2 s−1), and salinity (5–40 psu) on the growth of both populations were assessed. Plantlets of Gayralia sp. 1 from in vitro cultures showed a broader tolerance to all salinity and irradiance levels tested, with the highest growth
rate (GR; mean 17% day−1) at 21.5°C and 100 μmol photons m−2 s−1. Plantlets of Gayralia sp. 1 collected during the winter in the field showed higher GR, ranging from 5% day−1 to 7.5% day−1 in salinities from 20 to 40 psu, and 2.0% day−1 and 4.3% day−1 for plantlets collected during the summer. Gayralia sp. 2 from the field showed highest GR at salinity of 15 psu. These results suggest distinct physiological responses of the
two species, in accordance with their distribution: Gayralia sp. 2 is limited to the inner areas of the estuary, while Gayralia sp. 1 grows in outer areas, where salinity values are higher than 20 psu. These data indicate that Gayralia sp. 1 has a higher potential for aquaculture than Gayralia sp. 2 due to its larger thalli, higher GR, and wider tolerance to environmental variations. 相似文献
4.
Porphyra vietnamensis Tanaka & Pham-Hoang Ho (Bangiales, Rhodophyta) is a tropical seaweed collected from the west coast of India. Thalli of the blade phase are found growing only during the rainy season between July and September. They grow on rocky intertidal or subtidal substrata or as epiphytes on other seaweeds such as Enteromorpha flexuosa and Chaetomorpha media. The gametophytic thallus is monostromatic and covered with spines at the base. The species is monoecious. Male gametangia are found in patches that are distributed in the upper part of the thallus. Archeospores are found at the thallus margins and give rise to the blade phase after one week of germination even at 30 ∘ C. Zygotospores germinated at 25 ∘ C into conchocelis within three days from the date of their inoculation. Conchospores were released at 30 ∘ C. The young blades grew at 32 ∘ C in the laboratory. 相似文献
5.
Alvaro Israel Milagrosa Martinez-Goss Michael Friedlander 《Journal of applied phycology》1999,11(6):543-549
Acclimation responses of the red alga Gracilaria tenuistipitata var. liui collected on the northwest coast of Philippines were determined in laboratory setups and outdoor cultivation tanks in Haifa,
Israel. Growth under laboratory conditions was influenced by all three variables studied, namely, temperature (20 or 30 °C), salinity (20, 30 or39‰) and seawater pH (6.5, 7.0, 8.0 or ≥ 9.0). In 250 mL flasks lacking pH control growth was influenced
by temperature only at 20 ‰, whereas at 39 ‰, growth rates were similar at 20 or 30 °C. In 500 mL cylinders in which pH was controlled, growth rates were significantly different at a pH of 6.5 and 7.0 for all
salinities, with maximal rates occurring in 39 ‰. At pH 8.0, and above, growth rates between salinities were similar and reduced
to approximately 50% at a pH of 9.0 compared to rates at a pH of 6.5. Photosynthesis responses generally resembled growth
responses both, in 250 mL and 500 mL cultures. In 40-L outdoor tanks, weekly growth and agar yields were apparently enhanced
by increasing light intensities (up to full sunlight) and nutrient concentrations (up to 0.2 mM PO3
2- and 2.0 mM NH4
+), and rates averaged four times higher than rates determined in the smaller flask cultures. This study shows broad salinity
tolerance of G. tenuistipitata var. liui and its ability to sustain growth rates that are among the highest measured for Gracilaria spp. in outdoor cultures.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
The growth and lipid content of three Botryococcus braunii strains from China (CHN), United Kingdom (UK) and Japan (JAP) were compared at three temperatures (20, 25 and 30 ∘C), three irradiances (60, 100 and 300 W m−2) and four salinities (0, 0.15, 0.25, and 0.5 M NaCl) for 30 days, respectively. In the temperature trial, the UK strain and
JAP strain grew faster at 25 ∘C than at other temperatures, while the CHN strain performed equally well at 20 and 25 ∘C. The JAP strain grew slowest among the three strains at all temperatures, whereas the growth rate of the CHN and UK strains
was similar at all temperatures except at 20 ∘C. The UK strain contained the highest lipid content, but the CHN strain had the lowest lipid content at most temperatures.
In the light trial, the highest growth rate was found in the UK strain and the lowest growth rate was observed in the JAP
strain at most irradiances. The UK and JAP strains contained more lipids than the CHN strain at 60 and 100 W m−2, but the lipid content was not significantly different among the three strains at 300 W m−2. In the salinity trial, both the CHN and UK strains grew faster than the JAP strain at all salinities, but the growth rate
between the CHN and UK strains was not different. However, the CHN strain had the lowest lipid content whereas the UK strain
produced the highest lipids at most salinities. Our results indicate that the CHN strain and the UK strain grow faster than
the JAP strain, but the UK and JAP strains produce more lipids than the CHN strain. The UK strain should be considered as
a potential B. braunii strain for the exploitation of renewable energy. 相似文献
7.
Javier Orduña-Rojas Karla Y. García-Camacho Priscila Orozco-Meyer Rafael Ríosmena-Rodríguez Isaí Pacheco-Ruiz José A. Zertuche-González Alf E. Meling-López 《Journal of applied phycology》2008,20(2):169-175
Agar properties of two potentially commercial important seaweeds from the Gulf of California were studied. Maximum yield in
Gracilaria vermiculophylla (45.7%) occurred during the summer months, coinciding with high water temperatures (31°C) whereas minimum yields (11.6%)
were obtained during the coldest months of the year when populations of this species diminish in the bay. Gracilariopsis longissima showed two yield peaks, one in spring and another in fall, before the maximum and minimum seawater temperatures. Gel strength
in native agar from the two species was low (<22.5 g cm−2) for most of the year. G. vermiculophylla native agar showed a slight increase in gel strength from June to August, which were the hottest months. Maximum value was
85 g cm−1 in August. Maximum gel strength in G. longissima was observed in October (91 g cm−1), and an unusual native agar with no detectable gel strength was observed in March and April samples. Gelling temperatures
range from 27.7 to 36.5°C in G. vermiculophyla and from 26.6 to 34.9°C in G. longissima, meanwhile melting points were 73.9 – 53.5°C and 75.5 – 56.6°C, respectively. Sulfate content was high, 6.3–13.9% in G. vermiculophylla and 1.9–11.9% in G. longissima, and on the other hand 3,6 anhydrogalactose content was low 12.1–26.7% and 9.1–23%, respectively compared to other species.
Results obtained showed that mean native agar yields of Gracilaria vermiculophylla and Gracilariopsis longissima from the Gulf of California are comparable to other tropical Gracilaria. However, the low gel strength, high sulfate content and low 3,6 anhydrogalactose content observed in the native agar extracted
from these species make this an agaroid, thus alternative methods of extraction should be used to evaluate the possibility
of commercial utilization of both species. 相似文献
8.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献
9.
Vishal Gupta Manoj Kumar Puja Kumari C. R. K. Reddy Bhavanath Jha 《Journal of applied phycology》2011,23(2):209-218
This study reports on the optimization of protoplast yield from two important tropical agarophytes Gracilaria dura and Gracilaria verrucosa using different cell-wall-degrading enzymes obtained from commercial sources. The conditions for achieving the highest protoplast
yield was investigated by optimizing key parameters such as enzyme combinations and their concentrations, duration of enzyme
treatment, enzyme pH, mannitol concentration, and temperature. The significance of each key parameter was also further validated
using the statistical central composite design. The enzyme composition with 4% cellulase Onozuka R-10, 2% macerozyme R-10,
0.5% pectolyase, and 100 U agarase, 0.4 M mannitol in seawater (30‰) adjusted to pH 7.5 produced the highest protoplast yields
of 3.7 ± 0.7 × 106 cells g−1 fresh wt for G. dura and 1.2 ± 0.78 × 106 cells g−1 fresh wt for G. verrucosa when incubated at 25°C for 4–6 h duration. The young growing tips maximally released the protoplasts having a size of 7–15 μm
in G. dura and 15–25 μm in G. verrucosa, mostly from epidermal and upper cortical regions. A few large-size protoplasts of 25–35 μm, presumably from cortical region,
were also observed in G. verrucosa. 相似文献
10.
Production of biomass and phycocyanin (PC) were investigated in highly pigmented variants of the unicellular rhodophyte Galdieria sulphuraria, which maintained high specific pigment concentrations when grown heterotrophically in darkness. The parental culture, G. sulphuraria 074G was grown on solidified growth media, and intensely coloured colonies were isolated and grown in high-cell-density fed-batch
and continuous-flow cultures. These cultures contained 80–110 g L−1 biomass and 1.4–2.9 g L−1 PC. The volumetric PC production rates were 0.5–0.9 g L−1 day−1. The PC production rates were 11–21 times higher than previously reported for heterotrophic G. sulphuraria 074G grown on glucose and 20–287 times higher than found in phototrophic cultures of Spirulina platensis, the organism presently used for commercial production of PC. 相似文献
11.
Fish <1 year old were sampled during 1 year using nets inshore at South Georgia. Some fish were kept in aquaria. Growth rates
were estimated using the exponential model. During June to October 1980, field growth rates of Parachaenichthys georgianus and Champsocephalus gunnari were 0.33 and 0.48% SL day−1, respectively. Gobionotothen marionensis (1979 cohort) grew at 0.40% SL day−1 during June to November in the field, and 0.34% SL day−1 in the laboratory from September to March. Notothenia coriiceps grew at 0.28% SL day−1 in the laboratory during September to March. During November to December, Artedidraco mirus grew at 0.82% SL day−1 in the field. The 1980 cohort of G. marionensis grew at 1.39% SL day−1 during November to January in the field. During January, the field growth rate of G. gibberifrons was 1.39% SL day−1. Growth rates increased three-fold from winter to summer. Temperature can only explain one-half of this range in growth rates,
whereas all of this range can be explained by food availability. Therefore, seasonal food resource limitation has a major
effect on Antarctic fish growth.
Received: 30 June 1997 / Accepted: 7 September 1997 相似文献
12.
Voigt CC Kelm DH Visser GH 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2006,176(3):213-222
Recently, it was argued that extrinsic factors, such as high foraging costs, lead to elevated field metabolic rates (FMR).
We tested this suggestion by comparing the FMR of nectar-feeding and fruit-eating bats. We hypothesized that the foraging
effort per energy reward is higher for nectar-feeding mammals than for fruit-eating mammals, since energy rewards at flowering
plants are smaller than those at fruiting plants. Using the doubly labelled water method, we measured the FMR of nectar-feeding
Glossophaga commissarisi and fruit-eating Carollia brevicauda, which coexisted in the same rainforest habitat and shared the same daytime roosts. Mass-specific FMR of G. commissarisi exceeded that of C. brevicauda by a factor of almost two: 5.3±0.6 kJ g−1 day−1 for G. commissarisi and 2.8±0.4 kJ g−1 day−1 for C. brevicauda. Since nectar-feeding bats imbibe nectar droplets of only 193 J energy content during each flower visit, a G. commissarisi bat has to perform several 100 flower visits per night to meet its energy requirement. The fruit-eating C. brevicauda, on the other hand, needs to harvest only 3–12 Piper infructescenses per night, as the energy reward per Piper equals ca. 6–30 kJ. We argue that the flowering and fruiting plants exert different selective forces on the foraging behaviour
and energetics of pollinators and the seed dispersers, respectively. A comparison between nectar-feeding and non-nectar-feeding
species in various vertebrate taxa demonstrates that pollinators have elevated FMRs. 相似文献
13.
Six species of Gracilaria, G. corticata J. Agardh, G. crassa Harvey, G. millardetii J. Agardh, G. salicornia (J. Ag.) Dawson, G. verrucosa (Huds.) Papenfuss and Gracilaria sp, collected from different stations along the Kenya coast were studied. The yield of hot water native agar extract ranges from 8.1–30% of dry weight, with G. verrucosa and G. salicornia having the greatest and the least yield, respectively. The gel-strength of 1.5% agar solution was highest in G. verrucosa (220 g cm–2) and lowest in G. corticata (< 60 g cm – 2) whereas the highest gelling temperature was recorded for Gracilaria sp. (40.4 °C) and the lowest in G. verrucosa (28.9 °C). 3,6 anhydrogalactose content was the highest in G. verrucosa and the lowest in G. corticata while sulphate content was higher in the latter. 相似文献
14.
Yuan Zi Huo Shan Nan Xu Yang Yang Wang Jian Heng Zhang Yin Jiang Zhang Wei Ning Wu Ya Qu Chen Pei Min He 《Journal of applied phycology》2011,23(2):173-182
Due to the discharge of nutrients into the East China Sea, severe eutrophication has appeared in Hangzhou Bay. Therefore,
we cultivated Gracilaria verrucosa on a large scale in the Jinshan enclosed sea with an area of 1.72 km2 in the northern part of Hangzhou Bay to perform bioremediation. The Fengxian enclosed sea with an area of 2.3 km2 and 50 km far from Jinshan was used as the control. The results showed that the Hangzhou Bay was severely eutrophicated before
G. verrucosa cultivation. During the period of cultivation between August 2006 and July 2007, the annual growth rate of G. verrucosa was 9.42% day−1, and the sea water quality was improved from worse than grade IV to grades II–III, with the concentration of dissolved inorganic
nitrogen (DIN) and PO4-P significantly lower than that in the Fengxian enclosed sea (p < 0.01). The concentration of NH4-N, NO3-N, NO2-N, and PO4-P after G. verrucosa cultivation was decreased by 54.12%, 75.54%, 49.81%, and 49.00%, respectively. The density of phytoplankton in the Jinshan
enclosed sea with cultivation of G. verrucosa was 6.90 –126.53 × 104 cells m−3, which was significantly lower than that in the Fengxian enclosed sea. In addition, species diversity, richness, and evenness
was significantly increased after cultivation of G. verrucosa in the Jinshan enclosed sea compared with that in the Fengxian enclosed sea. The density of Skeletonema costatum, Prorocentrum micans, and Prorocentrum donghaiense, which were the usual species of red tides at the coastal sea of China, in the Jinshan enclosed sea with cultivation of G. verrucosa was significantly lower. Based on these results, if the water quality in the Jinshan enclosed sea were to be maintained at
grade I (DIN ≤0.20 mg L−1) or II (DIN ≤0.30 mg L−1), 21.8 t or 18.0 t fresh weight of G. verrucosa need to be cultivated, respectively. These results indicated that large-scale cultivation of G. verrucosa could play a significant role in the bioremediation of Hangzhou Bay. 相似文献
15.
Sou Nagasoe Dae-Il Kim Yohei Shimasaki Yuji Oshima Mineo Yamaguchi Tsuneo Honjo 《Harmful algae》2006,5(1):20-25
The effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee were examined in the laboratory. Exposed to 45 different combinations of temperature (10–30 °C) and salinity (0–40) under saturating irradiance, G. instriatum exhibited its maximum growth rate of 0.7 divisions/day at a combination of 25 °C and a salinity of 30. Optimum growth rates (>0.5 divisions/day) were observed at temperatures ranging from 20 to 30 °C and at salinities from 10 to 35. The organism could not grow at ≤10 °C. In addition, G. instriatum burst at a salinity of 0 at all temperatures, but grew at a salinity of 5 at temperatures between 20 and 25 °C. It is noteworthy that G. instriatum is a euryhaline organism that can live under extremely low salinity. Factorial analysis revealed that the contributions of temperature and salinity to its growth of the organism were almost equal. The irradiance at the light compensation point (I0) was 10.6 μmol/(m2 s) and the saturated irradiance for growth (Is) was 70 μmol/(m2 s), which was lower than Is for several other harmful dinoflagellates (90–110 μmol/(m2 s)). 相似文献
16.
Abstract
Freshwater ecosystems derive organic carbon from both allochthonous and autochthonous sources. We studied the relative contributions
of different carbon sources to zooplankton in a small, polyhumic, steeply stratified lake, using six replicate surface-to-sediment
enclosures established during summer and autumn 2004. We added 13C-enriched bicarbonate to the epilimnion of half the enclosures for three weeks during each season and monitored carbon stable
isotope ratios of DIC, DOC, POC and Daphnia, along with physical, chemical and biological variables. During summer, 13C-enriched DIC (δ13C up to 44 ± 7.2‰) was soon taken up by phytoplankton (δ13C up to −5.1 ± 13.6‰) and was transmitted to Daphnia (δ13C up to −1.7 ± 7.2‰), demonstrating consumption of phytoplankton. In contrast, during autumn, 13C-enriched DIC (δ13C up to 56.3 ± 9.8‰) was not transmitted to Daphnia, whose δ13C became progressively lower (δ13C down to −45.6 ± 3.3‰) concomitant with decreasing methane concentration. Outputs from a model suggested phytoplankton contributed
64–84% of Daphnia diet during summer, whereas a calculated pelagic carbon mass balance indicated only 30–40% could have come from phytoplankton.
Although autumn primary production was negligible, zooplankton biomass persisted at the summer level. The model suggested
methanotrophic bacteria contributed 64–87% of Daphnia diet during autumn, although the calculated carbon mass balance indicated a contribution of 37–112%. Thus methanotrophic
bacteria could supply virtually all the carbon requirement of Daphnia during autumn in this lake. The strongly 13C-depleted Daphnia values, together with the outputs from the models and the calculated carbon mass balance showed that methanotrophic bacteria
can be a greater carbon source for Daphnia in lakes than previously suspected. 相似文献
17.
The local species Gracilaria conferta and the foreign G. verrucosa were grown together under a wide range of photon flux density and temperature conditions. Gracilaria verrucosa showed a higher growth rate, especially under low temperatures, and higher photosynthetic performances as well as higher ribulose-1,5-bisphosphate carboxylase activity as compared with G. conferta. Gracilaria verrucosa also showed a better quality and yield of agar, suggesting that this species could be more suitable than G. conferta for outdoor cultivation in Israel and may improve winter growth in ponds. Growth rate and agar quality (gel strength) were rated as the most suitable characteristics influencing the preference of strains for outdoor cultivation. 相似文献
18.
Physiological responses of Pterocladia and Gelidium (Gelidiales,Rhodophyta) from the Azores,Portugal
Manometric studies were conducted on Pterocladia capillacea, Gelidium latifolium and Gelidium spinulosum from the Azores, Portugal to determine optimal values of temperature, light and salinity for growth. Physiological responses were considered in relation to vertical distribution patterns of these species commonly observed throughout the Azores. Optimal parameters for the growth of Pterocladia capillacea, Gelidium latifolium and G. spinulosum were 17 to 25 °C, a photon flux density between 200 and 300 µmol m–2 s–1 and salinities of 25 to 35. 相似文献
19.
Manoj Kumar Vladimir León Angela De Sisto Materano Olaf A. Ilzins 《World journal of microbiology & biotechnology》2007,23(2):211-220
A Bacillus sp. strain DHT, isolated from oil-contaminated soil, grew and produced biosurfactant when cultured in variety of substrate
at salinities of up to 100 g l−1 and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, various pure alkanes and PAHs as a sole carbon
and energy source across a wide range of temperature and salinity. Over the range evaluated, the degradation of hydrocarbon
and biosurfactant production was not influenced by salinity (0–10% wv−1) and temperature (30–45°C). The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane
as the best substrate and toluene as the poorest. From 16S rDNA analysis, strain DHT was related to Bacillus licheniformis. 相似文献
20.
Po Teen Lim Chui Pin Leaw Shigeru Sato Chu Van Thuoc Atsushi Kobiyama Takehiko Ogata 《Journal of applied phycology》2011,23(5):857-864
A clonal culture of a Vietnamese strain of Alexandrium minutum, AlexSp17, was subjected to different salinity treatments to determine the growth and toxin production of this strain that
produces a novel toxin analogue, deoxy GTX4-12ol. The experiment was carried out in batch cultures without pre-acclimatization
at seven salinity treatments from 5 to 35 psu, under constant temperature of 25°C, illumination of 140 μmol photon m−2 s−1, and 12:12 light/dark photoperiod. The strain grew in all salinity treatments, with optimum growth at 10–15 psu. However,
the specific growth rate (0.2 day−1) was lower than those reported in Malaysian strains and other strains from different geographical areas. The optimum range
of salinity for the growth of this species agreed with field observations of the locality of origin. No significant change
in toxin profiles was observed at different salinities. The cellular toxin quota, Qt, was not affected by the salinity-dependent
growth rate. The toxin GTX4-12ol is presumed to be a transformation product of GTX4 from specific cellular reductase enzymes.
Further investigation at the molecular level of toxin biosynthesis and subcellular enzyme activities is needed to provide
insight in the production of this unique toxin analogue. 相似文献