Marilou P Sison-Mangus

University of California, Santa Cruz | UCSC · Department of Ocean Sciences

Auxospore production is a sexual reproductive strategy by diatoms to re-attain normal size after the size-reducing effect of clonal reproduction. Aside from the minimum size threshold used as a sex clock by diatoms, the environmental or chemical triggers that can induce sex in diatoms are still not well understood. Here we investigated the influenc...

Sargassum polycystum is an economically important seaweed endemic to Southeast Asian waters. Genetic diversity studies conducted for this alga have been based on samples from various areas in the Indo-Pacific region. Here, we examined the phylogenetic patterns of S. polycystum in Eastern Samar, Philippines using the nuclear ribosomal DNA (rDNA) reg...

Increasing occurrence of harmful algal blooms across the land–water interface poses significant risks to coastal ecosystem structure and human health. Defining significant drivers and their interactive impacts on blooms allows for more effective analysis and identification of specific conditions supporting phytoplankton growth. A novel iterative Ra...

Marine bacteria employ various strategies to maintain their competitive advantage over others in a mixed community. The use of Type VI Secretion Systems (T6SS), a protein secretion apparatus used as a molecular weapon for interbacterial competition and eukaryotic interactions, is one of the competitive strategies that is least studied among heterot...

Many aquatic organisms can thrive in polluted environments by having the genetic capability to withstand sub-optimal conditions. However, the contributions of microbiomes under these stressful environments are poorly understood. We investigated whether a mercury-tolerant microbiota can extend its phenotype to its host by ameliorating host survival...

Host-associated microbiota have been claimed to play a role in hosts' responses to parasitic infections, often protecting the hosts from infection. We tested for such a role in the crustacean Daphnia and the parasitic bacterium Pasteuria ramosa, a widely used model system for host-parasite interactions. We first determined the infection phenotype (...

The successional dynamics of microbial communities are influenced by the synergistic interactions of physical and biological factors. In our motivating data, ocean microbiome samples were collected from the Santa Cruz Municipal Wharf, Monterey Bay at multiple time points and then 16S ribosomal RNA (rRNA) sequenced. We develop a Bayesian semiparamet...

Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and...

Importance: Little is known about how human pathogens respond, and adapt to ever changing parameters of natural habitats outside of the human host and how environmental adaptation alters dissemination. Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, experiences fluctuations in temperature in its natural aquatic habita...

Microbiota have diverse roles in the functioning of their hosts; experiments using model organisms have enabled investigations into these functions. In the model crustacean Daphnia, little knowledge exists about the effect of microbiota on host well being. We assessed the effect of microbiota on Daphnia magna by experimentally depriving animals of...

The association of phytoplankton with bacteria is ubiquitous in nature and the bacteria that associate with different phytoplankton species are very diverse. The influence of these bacteria in the physiology and ecology of the host and the evolutionary forces that shape the relationship are still not understood. In this study, we used the Pseudo-ni...

The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has...

Background The increase in availability of genomic sequences for a wide range of organisms has revealed gene duplication to be a relatively common event. Encounters with duplicate gene copies have consequently become almost inevitable in the context of collecting gene sequences for inferring species trees. Here we examine the effect of incorporatin...

Taxa and genes used in this study. GenBank accession numbers for genes newly sequenced and included in study.

Trees from combined and individual analyses of slow-evolving-copy genes. The maximum likelihood topologies presented were recovered using the same alignment used to generate Figure 1 (maximum parsimony) and Figure 2 (Bayesian).

Trees from combined and individual analyses of fast-evolving-copy genes. The maximum parsimony, maximum likelihood and Bayesian analyses of fast-evolving-copy genes recovered identical topologies.

Primers used in the study. The sequences represent primers used in 5'RACE of opsin genes.

Sequence alignments used in this study. Amino acid alignments of UVRh, BRh, LWRh, EF-1α and COI.

Penalized likelihood age estimates. The data provided represent estimates calculated from alignments including either slow- or fast-evolving copies of duplicate genes.

Divergence time estimates. The data in the figure show the impact of incorporating fast-evolving genes on Bayesian divergence time estimates using priors of age of ingroup node = 70 Ma, rtrate = 0.002 substitutions per site per million years and brownmean = 0.02.

Bayesian age estimates. The data provided represent estimates obtained using the slow-evolving-copy gene data set and several combinations of prior values.

Bayesian age estimates. The data in the table represent estimates obtained using the fast-evolving-copy gene data set and several combinations of prior values.

The functional significance of gene duplication is rarely addressed at the level of animal behavior. Butterflies are excellent models in this regard because they can be trained and the use of their opsin-based visual pigments in color vision can be assessed. In the present study, we demonstrate that the lycaenid Polyommatus icarus uses its duplicat...

Butterfly long-wavelength (L) photopigments are interesting for comparative studies of adaptive evolution because of the tremendous phenotypic variation that exists in their wavelength of peak absorbance (lambda(max) value). Here we present a comprehensive survey of L photopigment variation by measuring lambda(max) in 12 nymphalid and 1 riodinid sp...

Butterflies and primates are interesting for comparative color vision studies, because both have evolved middle- (M) and long-wavelength- (L) sensitive photopigments with overlapping absorbance spectrum maxima (lambda(max) values). Although positive selection is important for the maintenance of spectral variation within the primate pigments, it rem...

Although previous investigations have shown that wing coloration is an important component of social signaling in butterflies, the contribution of opsin evolution to sexual wing color dichromatism and interspecific divergence remains largely unexplored. Here we report that the butterfly Lycaena rubidus has evolved sexually dimorphic eyes due to cha...

The basic precondition for color vision is the presence of at least two receptor types with different spectral sensitivities. The sensitivity of a receptor is mostly defined by the opsin-based visual pigment expressed in it. We show here, through behavioral experiments, that the nymphalid butterfly Heliconius erato, although it expresses short and...

The continuous increase of human activities in the tropical coastal zones threatens the water quality necessary for cultivating giant clams. In order to investigate the potential for disturbances, of natural and/or anthropogenic origin, to affect growth in giant clams, transplantation experiments were conducted in the north of the Philippines. Afte...

have compared the random-ampli®edpolymorphic 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 dino¯agellate symbionts using allozyme analysis. Comparisons of 163 RAPD characters by unweighted pair-group arithmetic-average cluster a...

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 clu...

This study investigated the effects of different clonal strains of Symbiodinium sp. (zooxanthellae) on clam growth and survival, while monitoring the persistence of the induced symbioses in outdoor tanks and in the field using allozyme and random amplified polymorphic DNA (RAPD) analyses. Aposymbiotic clam larvae that were inoculated with homologou...

The taxonomy of zooxanthellae in marine invertebrate symbioses is not well understood owing mainly to their lack of reliable morphological differences. Nevertheless, previous work using protein and DNA electrophoreses has set the stage for advancing our taxonomic understanding of cnidarian zooxanthellae. Here we present the use of allozymes as gene...