Journal Articles - UP - MSI
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- Genetic variation in Symbiodinium isolates from giant clams based on random-amplified-polymorphic DNA (RAPD) patternsBaillie, B. K.; Belda-Baillie, C. A.; Silvestre, V.; Sison, M.; Gomez, A. V.; Gomez, E. D.; Monje, V. (Springer, 2000-06-16)We have compared the random-amplified-polymorphic DNA (RAPD) patterns of Symbiodinium isolates from seven species of giant clams to investigate the large genetic variation that we previously reported for this group of dinoflagellate symbionts using allozyme analysis. Comparisons of 163 RAPD characters by unweighted pair-group arithmetic-average cluster analysis (UPGMA) corroborate our previous findings that giant clams associate with a large number of genetically distinguishable algal symbionts, and that the isolates from a single Tridacna gigas individual form a group of closely related algae. However, the overall topology of the UPGMA tree constructed from RAPD data differs from that of the previous allozyme data, indicating that the combined data we have collected to date are insufficient to accurately infer phylogenetic affiliations between the isolates studied. Comparisons of our data set with those published for strains of Gymnodinium catenatum, a toxic dinoflagellate with a sexual life stage, shows that our isolates are even more diverse. Algal isolates from giant clams have a level of RAPD variation comparable to organisms that are able to undergo sexual recombination. This study demonstrates the sensitivity of the RAPD technique in detecting genetic diversity in this group of algae, and highlights the need for more comparative data for the major clades of Symbiodinium.
- Characterization of the UDP-glucose pyrophosphorylase gene from the marine red alga Gracilaria gracilisLluisma, Arturo O.; Ragan, Mark A. (Springer, 1998-12)UDP-glucose pyrophosphorylase (UGPase) is a key enzyme in carbohydrate metabolism, particularly polysaccharide biosynthesis, in red algae. In this report, we characterize at the genomic and cDNA levels the putative UGPase gene of the agarophytic red alga Gracilaria gracilis. The gene is single-copy, devoid of introns, and produces two kinds of transcripts that differ in size by 332 basepairs. The large and small transcripts appear to utilize distinct polyadenylation signals. The putative protein has 495 amino acids, and is about 50% identical in sequence to its homologs in plants, animals and fungi. Sequencing of the genomic clone revealed that another gene, potentially encoding a DNA helicase and containing a 76 bp-intron near its 3′ end, occurs 376 bp downstream of the UGPase gene.
- Characterization of a galactose-1-phosphate uridylyltransferase gene from the marine red alga Gracilaria gracilisLluisma, A. O.; Ragan, M. A. (Springer, 1998-08-27)The metabolism of D-galactose is a major feature of red-algal physiology. We have cloned and sequenced a gene from the red alga Gracilaria gracilis that encodes a key enzyme of D-galactose metabolism, galactose-1-phosphate uridylyltransferase (GALT). This gene, designated GgGALT1, is apparently devoid of introns. A potential TATA box, four potential CAAT boxes, and a repeated sequence occur in the 5′-flanking region. The predicted 369-aa peptide shares significant sequence similarity with GALTs from other organisms (human, 47%; Saccharomyces cerevisiae, 49%; Solanum tuberosum, 49%). Southern-hybridization analysis reveals two related, but apparently not identical, GALT genes in the nuclear genome of G. gracilis. Sequence analysis indicates that the GgGALT1 enzyme lacks a rubredoxin “knuckle” motif, which in bacterial and fungal GALTs is involved in binding zinc. An open reading frame encoding a potential peptidyl tRNA hydrolase occurs 179 bp downstream from the GgGALT1 gene.
- Agelasine F from a Philippine Agelas sp. sponge exhibits in vitro antituberculosis activityMangalindan, Gina; Talaue, Meliza; Cruz, Lourdes; Franzblau, Scott; Adams, Linda; Richardson, Adam; Ireland, Chris; Concepcion, Gisela (Georg Thieme Verlag KG, 2000-12-31)Marine sponge samples were collected in Baler, Aurora, Philippines, and extracts were tested for in vitro antituberculosis activity. An orange Agelas sp. sponge yielded the known compound, agelasine F, which inhibited some drug resistant strains of Mycobacterium tuberculosis in vitro at concentrations as low as 3.13 μg/ml. Activity against M. tuberculosis residing within macrophages required concentrations of 13 - 22 μg/ml which was below the IC50 for Vero cells (34 μg/ml).
- Influence of tidal location on morphology, photosynthesis and pigments of the agarophyte, Gelidiella acerosa, from Northern PhilippinesGanzon-Fortes, E. T. (Springer, 1997-12)The red seaweed agarophyte, Gelidiella acerosa (Forsskål) (Feldmann& Hamel) was collected from tidepools, high intertidal rocks, and shallow subtidal areas along a reef flat in Ilocos Norte, northern Philippines. The three populations were compared during the summer (dry) and rainy (wet) seasons to determine changes in morphology and photoacclimation capacity as possible use in mariculture. During summer months (February to April) after exposure to environmental extremes (i.e. the highest percent of minus tides during daylight, high light regimes, desiccation, and solar bleaching), the populations differed in their morphologies and responses to increasing irradiance levels (P–I curve). Tidepool plants were the tallest, bushiest, and with increased diameter of cortical cells; while, high intertidal plants were the shortest, with sparse branching pattern and decreased diameter of cortical cells. Although their saturation irradiances indicated shade tolerance (Ik = 52 − 112 µmol photon m -2 s-1). Their differential light saturation curves (P-I curves) suggested a capacity to acclimate to ambient light regimes. For example, plants from the high intertidal zone showed higher photosynthetic rates and saturation irradiances, slightly lower initial slopes of the P-I curves and levels of light harvesting accessory pigments, rphycoerhythrin (R-PE) and rphycocyanin (R-PC), after being exposed to higher light regimes. In contrast, plants from tidepools and shallow subtidal areas had lower photosynthetic rates and saturation irradiances, slightly steeper initial slopes of the P-I curves and levels of R-PE and R-PC, having been exposed to lower light regimes. During the rainy months (June to November) no significant responses in these parameters were recorded. Comparison of the P-I responses of vegetative and tetrasporic plants showed these to vary with season. The data suggest that when plants became reproductive their physiological fitness either was unchanged or slightly enhanced. These results indicate that all three populations of G. acerosa could be used as seed stock for mariculture.
- Contrasting recolonization strategies in multi-species seagrass meadowsRollon, Rene N.; Van Steveninck, Erik D.De Ruyter; Van Vierssen, Wim; Fortes, Miguel D. (Elsevier BV, 1999-12)This study shows that in a multi-species seagrass meadow in a shallow and clear-water site, all the former seagrass species were able to recolonize in the artificially created gaps of 0.25 m2 in size within ca. 2 yr. Extrapolation of the recolonization curves of the different species predicted a full recovery within 10 yr post-disturbance. Fitted curves for the dominant species Enhalus acoroides and Thalassia hemprichii showed contrasting strategies, the latter having a comparatively high intrinsic rate, achieving full recovery within ca. 2 yr post-disturbance. E. acoroides was the latest species to establish and the projected full-recovery time was among the longest (ca. 10 yr). The effect of timing of gap creation was generally not significant (except for Syringodium isoetifolium) neither was the temporal variation in density of most species outside the gaps. As recolonization by sexual propagules was found to be low, increasing the gap size would most probably require a much longer recovery period. A crude estimate for E. acoroides would be >10 yr for 1 m2 of gap. Further, since the densities of most seagrass species vary significantly between sites, and colonization rates depend on adjacent seagrass densities, the recovery curves would also be different across sites.
- The spasmodic peptide defines a new conotoxin superfamilyLirazan, Marcelina B.; Hooper, David; Corpuz, Gloria P.; Ramilo, Cecilia A.; Bandyopadhyay, Pradip; Cruz, Lourdes J.; Olivera, Baldomero M. (American Chemical Society (ACS), 2000-01-29)We purified and characterized a peptide from the venom of Conus textile that makes normal mice assume the phenotype of a well-known mutant, the spasmodic mouse. This “spasmodic” peptide has 27 amino acids, including two γ-carboxyglutamate (Gla) residues. A cDNA clone encoding the precursor for the peptide was identified; a γ-carboxylation recognition signal sequence (γ-CRS) is present in the −1 → −20 region of the peptide precursor. Both the γ-CRS and the position of the Gla residues in the mature toxin are notably different from other Gla-containing conopeptides. The spasmodic peptide has a novel disulfide framework and distinct signal sequence which together define a new P-superfamily of conopeptides. A cDNA encoding another member of the P-superfamily was identified from a different species, Conus gloriamaris.
- Stoichiometric interpretations of C:N:P ratios in organic waste materialsDiego-McGlone, Maria Lourdes San; Smith, Stephen V.; Nicolas, Vivian F. (Elsevier BV, 2000-04)Stoichiometric proportionalities were derived that can be used to convert reported BOD values of organic wastes to C, N and P estimates. Ratios to approximate the dissolved inorganic fractions of N and P from reported TN and TP values were also obtained. Stoichiometric ratios were determined for various kinds of organic waste load.
- γ-Irradiation in the extraction of agar from Gelidiella acerosa (Forsskaal) Feldmann et HamelVillanueva, R. D.; Rumbaoa, R. O.; Gomez, A. V.; Loquias, M. M.; de la Rosa, A. M.; Montaño, N. E. (Walter de Gruyter GmbH, 1998)The yield and quality of agar extracted from γ-irnidialcd Gelidiella acerosa were evaluated. Increasing radiation dose resulted in increasing agar yield. A radiation dose of 15 kGy caused a yield increase of 130%; however, the quality of agar was adversely affected as shown by the decrease in gel strength. Chemical analyses indicated that irradiation decreased the 3,6-anhydrogalactose content of agar, whereas, the sulfate level did not vary significantly. A comparison between boiling and pressure-cooking as methods of agar extraction showed that the latter increased agar yield, but lowered quality.
- Growth, agar yield and quality of selected agarophyte species from the PhilippinesAraño, K. G.; Trono, G. C.; Montaño, N. E.; Hurtado, A. Q.; Villanueva, R. D. (Walter de Gruyter GmbH, 2000-01-30)Three local agarophyte species (Gracilaria firma, Gracilaria sp. and Gracilariopsis bailinae) were grown under controlled outdoor flow-through culture conditions. Growth rates and agar characteristics of the three species were determined. Gracilaria firma showed superior growth and agar quality among the three species. It exhibited the highest growth rate, highest agar gel strength and was observed to be highly resistant to epiphytes. Growth experiments under various light and ammonium combinations showed that the highest photon flux density level (900 μ mol m−2s−1) and moderate ammonium (150 μM NH4Cl) concentration gave the highest growth rates for all species. The single and interactive effects of light and ammonium enrichment on growth and agar characteristics of the three species were highly significant.