Phycology

Metabolic rates and primary productivity of the marine macroalgae Dictyopteris delicatula in Taganga Bay, Colombian Caribbean

by Juan Diego Gaitán-Espitia

Revista de Biologíia Marina y Oceanografíia, 2011

Metabolic rates and photosynthetic performance of Dictyopteris delicatula were measured in the south of
Taganga... more Metabolic rates and photosynthetic performance of Dictyopteris delicatula were measured in the south of
Taganga Bay and on Inca-Inca beach, Colombia, during September and November 2007, as part of a monitoring program
of water quality and pollution associated with the stormwater system of the city of Santa Marta. Concentrations of
chlorophyll-a of D. delicatula did not show significant differences between both areas but the average rates of net
primary productivity and respiration differed significantly, likely due to the effect of the nutrient loadings from the
stormwater outlet in Taganga Bay, altering the physiological processes of the macroalgal community

Pozdně středověká štola ve Vimperku : příspěvek archeobotaniky rozsivek k určení funkce vodovodního díla - A Late Medieval adit in Vimperk, Czech Republik : archaeological and diatom Analysis

by Jaromír Beneš

Co-authored with J. Kaštovský, A. Majer

Case study about using diatom analysis in medieval archaeology defining quality of water in the Late Medieval adit in... more Case study about using diatom analysis in medieval archaeology defining quality of water in the Late Medieval adit in town of Vimperk, South Bohemia. First use of diatom analysis in Czech archaeology.

Význam analýzy druhového spektra rozsivek (Bacillariophyceae) pro archeologii - The use of diatom analysis (Bacillariophyceae) in archaeology

by Jaromír Beneš

In Czech, co-authored with J. Kaštovský

Article for Czech archaeologist summarizing use of diatom analysis in archaeology Article for Czech archaeologist summarizing use of diatom analysis in archaeology

Young Voices - An Applied Theatre Method Aiming to Bridge the Gap Between Youth and Adults

by yiota demetriou

Thesis for MA by Research at SANM - University of Hull, 2010-2011

This dissertation focuses on an applied theatre project, Young Voices that has attempted to develop a method, which... more This dissertation focuses on an applied theatre project, Young Voices that has attempted to develop a method, which inquires how performance forms can facilitate youth inclusion. Issues related to young people have been discussed extensively throughout time and within many disciplines. Stanley Cohen (1972), J.J Arnett (1999), Sharon Nichols and Thomas Good (2004) and Monica Barry (2005), have examined the ‘anxieties’ that are often associated with the perceived image of young people in society and how these may often lead to their social exclusion. This method is to be used by youth workers with their role as ‘intercessors’ between young people and the adults that surround them (i.e. their parents, guardians, teachers); it adopts Augusto Boal’s Theatre of the Oppressed (TO) ethos, uses elements of his Forum Theatre (FT) workshop techniques and the theory/technique of verbatim theatre. The project’s research process is in the form of applied and verbatim theatre workshops; performance presentation and a performance lecture addressed to youth workers. The method looks at increasing and facilitating communication between various isolated adolescent groups through applied theatre using various ‘Boalian’ workshop techniques and FT to identify the participants ‘oppressions’. It intends at facilitating communication through applied theatre and verbatim theatre between youth and youth workers, by capturing the participants ‘oppressions’ and presenting them to an audience of their peers and youth workers. And it aims at facilitating communication through the combination of applied theatre and verbatim theatre with the attempt of beginning to bridge the gap amongst young people and the adults around them, through a recommended step by suggesting the involvement of the participant’s surrounding adults. The Young Voices method has been developed from the collaboration of several youth groups from around Scarborough and its district. The complete process attempts to assist teenagers in discussing their concerns from their own perspectives towards empowering them and raising awareness about how their opinions should be required for matters that concern them.

Antagonistic interactions between filamentous heterotrophs and the cyanobacterium Nostoc muscorum

by Miro Svercel

Background

Little is known about interactions between filamentous heterotrophs and filamentous... more Background

Little is known about interactions between filamentous heterotrophs and filamentous cyanobacteria. Here, interactions between the filamentous heterotrophic bacteria Fibrella aestuarina (strain BUZ 2) and Fibrisoma limi (BUZ 3) with an axenic strain of the autotrophic filamentous cyanobacterium Nostoc muscorum (SAG 25.82 ) were studied in mixed cultures under nutrient rich (carbon source present in medium) and poor (carbon source absent in medium) conditions.

Findings

F. aestuarina BUZ 2 significantly reduced the cyanobacterial population whereas F. limi BUZ 3 did not. Physical contact between heterotrophs and autotroph was observed and the cyanobacterial cells showed some level of damage and lysis. Therefore, either contact lysis or entrapment with production of extracellular compounds in close vicinity of host cells could be considered as potential modes of action. The supernatants from pure heterotrophic cultures did not have an effect on Nostoc cultures. However, supernatant from mixed cultures of BUZ 2 and Nostoc had a negative effect on cyanobacterial growth, indicating that the lytic compounds were only produced in the presence of Nostoc. The growth and survival of tested heterotrophs was enhanced by the presence of Nostoc or its metabolites, suggesting that the heterotrophs could utilize the autotrophs and its products as a nutrient source. However, the autotroph could withstand and out-compete the heterotrophs under nutrient poor conditions.

Conclusions

Our results suggest that the nutrients in cultivation media, which boost or reduce the number of heterotrophs, were the important factor influencing the outcome of the interplay between filamentous heterotrophs and autotrophs. For better understanding of these interactions, additional research is needed. In particular, it is necessary to elucidate the mode of action for lysis by heterotrophs, and the possible defense mechanisms of the autotrophs.

Cultivation of filamentous cyanobacteria (blue-green algae) in agro-industrial wastes and wastewaters

by Marwa Eldalatony

Recently research interest has focused on the production of biofuel from microalgae. Microalgae are photosyntheticmore Recently research interest has focused on the production of biofuel from microalgae. Microalgae are photosynthetic
microorganisms that grow utilizing solar energy, nevertheless, the quantities of fertilizers
that should be used for their production are enormous. One alternative to the use of synthetic fertilizers
is to employ wastes and wastewaters (W&WWs), especially from the agro-industrial sector which are
rich in inorganic pollutants such as nitrogen and phosphorus, which can be recovered. Simultaneously
with the cultivation of microalgae using wastes and wastewaters for biomass production, treatment of
the wastes and wastewaters occur through removal of the pollutants. Filamentous cyanobacteria appear
to be suitable candidates for cultivation in wastes and wastewaters because they produce biomass in satisfactory
quantity and can be harvested relatively easily due to their size and structure. In addition their
biomass composition can be manipulated by several environmental and operational factors in order to
produce biomass with concrete characteristics. Herein we review the factors that affect the biomass composition
of cyanobacteria and present several studies that discuss the culture of filamentous cyanobacteria
in agro-industrial wastes and wastewaters, with special emphasis on Spirulina

Carrageenan of Eucheuma isiforme (Solieriaceae, Rhodophyta) from Nicaragua

by Yolanda Freile-Pelegrín

Antibacterial activity of montmorillonites modified with silver

by Yolanda Freile-Pelegrín

Co authored with S.M. Magana, P. Quintana, D.H. Aguilar, J.A. Toledo, C. Angeles-Chavez, M.A. Cortes, L. Leon, T. Lopez, R.M. Torres Sanchez

The antibacterial properties of silver modified montmorillonites from Pellegrini Lake, Argentina were tested in growth... more The antibacterial properties of silver modified montmorillonites from Pellegrini Lake, Argentina were tested in growth inhibition of Escherichia
coli bacteria. Montmorillonite was first submitted to different treatments: (a) calcination at 550 ◦C for 3 h and (b) grinding during 300 s. After that,
the samples were loaded with silver by ion exchange. Structural characterization was performed by X-ray diffraction (XRD), Fourier transformed
infrared spectroscopy (FTIR), and BET specific surface area measurements. Scanning electron microscopy (SEM) and high resolution transmission
electron microscopy (HRTM) showed that metallic silver nanoparticles precipitates over the clay surface after silver modification. Nevertheless, the
displacement of the (0 0 1) reflection observed by XRD in the calcined sample, and the diminution in Na+ content evaluated by energy dispersive
X-ray spectroscopy (EDXS), indicate that Ag ions were interchanged in the structure of the clays. Both samples showed good antibacterial activity
against E. coli, measured by the disk susceptibility and the minimum inhibitory concentration (MIC) tests. The ground montmorillonite required
a lower MIC than the thermally treated, although the last one presented a bigger inhibition zone in the disk method. The results shows that the
antibacterial activity is generated by the Ag+ present in the clay, as confirmed by X-ray photoelectronic spectroscopy (XPS); however the overall
antibacterial properties are affected by the availability of the ionic silver to be in contact with the bacteria.

The Tropical Brown Alga Lobophora variegata: A Source of Antiprotozoal Compounds

by Yolanda Freile-Pelegrín

Co authored with Zulema Cantillo-Ciau, Rosa Moo-Puc, Leovigildo Quijano

Lobophora variegata, a brown alga collected from the coast of the Yucatan
peninsula, Mexico, was studied for... more Lobophora variegata, a brown alga collected from the coast of the Yucatan
peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis,
Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest
activity against T. vaginalis, with an IC50 value of 3.2 μg/mL. For the fractions, the best
antiprotozoal activity was found in non-polar fractions. The chloroform fraction of the
extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as
1-O-palmitoyl-2-O-myristoyl-3-O-(6´´´-sulfo-α-D-quinovopyranosyl)-glycerol (1), together
with small amounts of 1,2-di-O-palmitoyl-3-O-(6´´´-sulfo-α-D-quinovopyranosyl)-glycerol (2)
and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6´´´-sulfo-α-Dquinovopyranosyl)-
glycerol (3). Their structures were elucidated on the basis of chemical
and enzymatic hydrolysis and careful analysis of FAB-MS and NMR spectroscopic data.
This is the first report on the isolation of SQDGs from L. variegata. The mixture of 1–3
showed good activity against E. histolytica and moderate activity against T. vaginalis with
IC50s of 3.9 and 8.0 μg/mL, respectively, however, the activity of 1–3 is not as effective as
metronidazole. These results afford ground information for the potential use of the whole
extract and fractions of this species in protozoal infections.

Antibacterial activity in marine algae from the coast of Yucatan, Mexico

by Yolanda Freile-Pelegrín

Co-authored with Juan Luis Morales

Citation Information. Botanica Marina. Volume 47, Issue 2, Pages 140–146, ISSN (Print) 0006-8055, DOI: 10.1515/BOT.2004.014, April 2004

Ethanolic and lipid-soluble extracts from 21 marine algal species (10 Chlorophyta, 2 Phaeophyta and 9 Rhodophyta) from... more Ethanolic and lipid-soluble extracts from 21 marine algal species (10 Chlorophyta, 2 Phaeophyta and 9 Rhodophyta) from the coast of Yucatan, Mexico, were evaluated for antibacterial activity against pathogenic microbes (4 Gram-positive, 5 Gram-negative and one fungus). All species with antibacterial activity (18) were active against the Gram-positive bacteria (Bacillus subtilis, Streptococcus faecalis and Micrococcus luteus), and most of the algal species exhibited activity against B. subtilis (89% in ethanolic soluble extracts and 94% in lipid-soluble extracts). The lipid-soluble extract of Ceramium nitens exhibited the highest activity among the species tested. The results are significant because no antibacterial activity has been found in previous research on this, or any other, species from this genus. The antimicrobial activities associated with extracts from different thallus regions (apical, basal and stolon) of selected Caulerpa species (C. ashmeadii, C. paspaloides and C. prolifera) were also evaluated. Results generally indicate that the stolon of Caulerpa has the highest antibacterial activity.

Mariculture of Kappaphycus alvarezii (Rhodophyta, Solieriaceae) color strains in tropical waters of Yucata´n, Me´xico

by Daniel Robledo

Co-authored with Julieta Munoz and Yolanda Freile-Pelegrin

Three color strains of the n-carrageenan producing red alga Kappaphycus alvarezii were cultured in Dzilam, Yucata´n,... more Three color strains of the n-carrageenan producing red alga Kappaphycus alvarezii were cultured in Dzilam, Yucata´n, over a 6-month period using the fixed off bottom monoline culture
method to determine the technical viability of producing commercially this seaweed in the tropical waters of the Yucata´n peninsula. Seawater temperature ranged from 28 to 31 8C, with a daily fluctuation range between 25.9 and 31.9 8C. Irradiance showed a strong fluctuation along the
study period with maximal recorded irradiance during April (881.8 Amol photon m
2 s
1). Ammonia accounted for 55.1–89.8% of total DIN depending on the season, and salinity did not change significantly. Temperature was the only environmental factor that explained 96% of the
observed variation in K. alvarezii growth rate (R2=0.96). The highest average growth rates obtained were 6.5F1% day
1 for the red strain, 7.1F1.8% day
1 for the brown strain, and
8.1F1.6% day
1 for green strain during June. Lowest growth rates were obtained during August and September for the green strain (2.0F0.6% day
1). Despite the significant differences in growth between months no significant differences among color strains were found ( PN0.05). The
growth rates of K. alvarezii were exponential during April to June. A 10-fold increase in weight was obtained after 30 days in cultivation for all the colored strains. As propagule weight increased the growth rate was reduced. Further, biomass yield (% weight gained) fluctuated as propagule weight increased and averaged 33.2F8.4% for the green, 35.4F6.0% for the red and 36.3F10.8% for the brown strain after 15 days. The highest carrageenan yield was obtained for the green strain (40.7%), whereas average carrageenan yields for the red strain were 32.7F3.9% and 37.5F1.1% for the brown. This study shows that K. alvarezii can be grown in the tropical waters of the Yucata´n peninsula during the dry and part of the wet season. This period coincided with the closed
season of the main fisheries. Thus, seaweed farming could be proposed as an alternative activity in the area.

Physiological characterization of Dunaliella sp. (Chlorophyta, Volvocales) from Yucatan, Mexico

by Daniel Robledo

Co-authored with Francisca Garcıa, Yolanda Freile-Pelegrın

Physiological responses of Dunaliella salina and Dunaliella viridis, isolated from solar saltworks on the Yucatan... more Physiological responses of Dunaliella salina and Dunaliella viridis, isolated from solar saltworks on the Yucatan Peninsula, were studied. Optimal growth temperature for D. salina was 22 C (3.06 · 106 cells mL1) and 26 C for D. viridis (4.04 · 106 cells mL1). Total carotenoid content in D. salina increased with temperature to a maximum of 35.14 pg cell1 at 38 C. Dunaliella salina a-carotene and bcarotene content was 0.083 ± 0.003 and 0.598 ± 0.020 mg 100 g dry wt1 respectively, whereas lower values were found in D. viridis cultured
under same experimental conditions (0.018 ± 0.002 and 0.136 ± 0.012 mg 100 g dry wt1 respectively). The highest specific growth rate in D. salina was obtained at 10% NaCl (0.28 d1), while its cell volume increased from 524 to 2066.93 lm3 when cultured from 10% to 35% NaCl. Maximum photosynthetic rates were attained when increasing from optimal growing temperature to 30 C for D. viridis (108 nmol O2 lg chl a h1) and D. salina (139 nmol O2 lg chl a h1). Photosynthetic responses to temperature variations indicated physiological adjustments in both species, with higher acclimation in D. salina. Evaluation of physiological attributes of these species
will be used for to carry out mass cultivation.

MORPHOLOGY AND PHOTOSYNTHESIS OF CAULERPA (CHLOROPHYTA) IN RELATION TO GROWTH FORM

by Daniel Robledo

Co-authored with L Collado-Vides

Morphological and photosynthetic performance
were analyzed in species of the genus Caulerpa from
an exposed... more Morphological and photosynthetic performance
were analyzed in species of the genus Caulerpa from
an exposed coral reef and a sheltered reef lagoon.
Morphological characters, such as distance between
modules, number of modules, stolon branches and
rhizoid clusters per centimeter of stolon, indicated
a uniformity among species within a specific habitat.
‘‘Guerilla,’’ or diffusive, growth forms were characteristic
for lagoon species and ‘‘phalanx,’’ or compact,
growth forms for reef species. Differences in
photosynthesis were found between Caulerpa species.
Sun-tolerant species were found on the reef,
and both sun- and shade-tolerant species were present
in the lagoon. In the lagoon, shade-tolerant species,
such as C. lanuginosa J. Agardh, were found
growing in the understory, and sun-tolerant species,
such as C. paspaloides (Bory) Greville, formed the
canopy. C. cupressoides (West in Vahl) C. Agardh was
the only species found in both environments; it
showed higher photosynthetic rates and a compressed
morphology when growing on the reef and
lower photosynthetic rates and expanded morphology
for lagoonal ramets. These results suggest that
C. cupressoides possesses a broad phenotypic ability
to acclimate to lagoonal and reef settings in comparison
to other Caulerpa species, enhancing its ecological
success in this particular system.

Seasonal variation in photosynthesis and biochemical composition of Caulerpa spp. (Bryopsidales, Chlorophyta) from the Gulf of Mexico

by Daniel Robledo

Co-authored with Yolanda Freile-Pelegrín

Photosynthesis, pigment content, soluble carbohydrate, and protein levels of six Caulerpa species were examined on... more Photosynthesis, pigment content, soluble carbohydrate, and protein levels of six Caulerpa species were examined on a
seasonal basis from samples taken along the northern coast of the Yucatan Peninsula, Mexico, between June 1998 and
August 1999. For Caulerpa ashmeadii, C. mexicana, C. paspaloides, and C. racemosa photosynthetic capacity changed depending on seasonal trends in photon flux density and water temperature in the study area. This pattern was not evident in Caulerpa prolifera and C. cupressoides. Maximum photosynthetic rates of 18.3 6 0.8 mg O2 g dry weight21 h21 were obtained in C. mexicana during the cold season. Photosynthetic efficiency (a) showed a similar pattern to that of Pmax coinciding with low irradiances (photon flux density [PFD]: 151 6 67 mmol photons m22 s21) and water temperature (23.8 6 1.98C), and the highest levels of dissolved inorganic nitrogen and dissolved reactive phosphorous in the water (9.1 mmol l21 and 0.5 mmol l21, respectively). Compensation (Ec) and saturation (Ek) irradiances were low and ranged from 3 to 35 and 44 to 280 mmol photons m22 s21, respectively. Maximum chlorophyll a and b (Chl a and b) levels occurred in C. racemosa and C. cupressoides during the cold to rainy seasons. The highest Chl b : a ratios were observed during the coldest months for all studied species. Protein and carbohydrate contents in Caulerpa spp. followed an inverse seasonal pattern. In
general, high protein levels were observed in the dry season coinciding with increasing light and seawater temperatures.
Photosynthesis in Caulerpa spp. from the Yucatan Peninsula coast is affected by high temperatures during the dry and rainy seasons. There is also a seasonal shift in the species proximate constituents indicative of a rapid growth period from January to May and a carbohydrate accumulation period during the rest of the year.

Regulation of two photosynthetic pigment-related genes during stress-induced pigment formation in the green alga, Dunaliella salina

by Daniel Robledo

Co-authored with L Sanchez-Estudillo, Yolanda Freile-Pelegrin, R Rivera-Madrid and JA Narvaez-Zapata

The expression of mRNAs coding for
1-deoxyxylulose-5-phosphate synthase (DXS)
and phytoene synthase (PSY)... more The expression of mRNAs coding for
1-deoxyxylulose-5-phosphate synthase (DXS)
and phytoene synthase (PSY) were studied in
Dunaliella salina grown under nitrogen-sufficient
(NS) and nitrogen-limited (NL) conditions. Under
NS conditions growth was 2.5 times higher
than under NL conditions. No differences were
found in chlorophyll a content per cell, and total
carotenoid content per cell was 5.33 pg 1)1 for
the NS treatment and 7.76 pg 1)1 for the NL.
DXS transcripts exhibited diminished expression
under NL conditions, peaking at day 15 of cultivation
in both treatments. Simultaneously, PSY
transcripts exhibited constant expression under
both conditions. These results suggest that these
genes play an important role in the balance of
photosynthetic pigments during pigment accumulation.

No habitat correlation of zooxanthellae in the coral genus Madracis on a Curaçao reef.

by Onno Diekmann

Prospects of biodiesel production from microalgae in India

by Marwa Eldalatony

Biodiesel production from heterotrophic microalgal oil

by Marwa Eldalatony

Microalgae for biodiesel production and other applications: A review

by Marwa Eldalatony

Biodiesel from microalgae

by Marwa Eldalatony