Driving south: a multi-gene phylogeny of the brown algal family Fucaceae reveals relationships and recent drivers of a marine radiation

<p>Abstract</p> <p>Background</p> <p>Understanding the processes driving speciation in marine ecosystems remained a challenge until recently, due to the unclear nature of dispersal boundaries. However, recent evidence for marine adaptive radiations and ecological speciation, as well as previously undetected patterns of cryptic speciation is overturning this view. Here, we use multi-gene phylogenetics to infer the family-level evolutionary history of Fucaceae (intertidal brown algae of the northern Pacific and Atlantic) in order to investigate recent and unique patterns of radiative speciation in the genus <it>Fucus </it>in the Atlantic, in contrast with the mainly monospecific extant genera.</p> <p>Results</p> <p>We developed a set of markers from 13 protein coding genes based on polymorphic cDNA from EST libraries, which provided novel resolution allowing estimation of ancestral character states and a detailed reconstruction of the recent radiative history. Phylogenetic reconstructions yielded similar topologies and revealed four independent trans-Arctic colonization events by Fucaceae lineages, two of which also involved transitions from hermaphroditism to dioecy associated with Atlantic invasions. More recently, reversion of dioecious ancestral lineages towards hermaphroditism has occurred in the genus <it>Fucus</it>, particularly coinciding with colonization of more extreme habitats. Novel lineages in the genus <it>Fucus </it>were also revealed in association with southern habitats. These most recent speciation events occurred during the Pleistocene glaciations and coincided with a shift towards selfing mating systems, generally southward shifts in distribution, and invasion of novel habitats.</p> <p>Conclusions</p> <p>Diversification of the family occurred in the Late-Mid Miocene, with at least four independent trans-Artic lineage crossings coincident with two reproductive mode transitions. The genus <it>Fucus </it>arose in the Pliocene but radiated within a relatively short time frame about 2.5 million years ago. Current species distributions of <it>Fucus </it>suggest that climatic factors promoted differentiation between the two major clades, while the recent and rapid species radiation in the temperate clade during Pleistocene glacial cycles coincided with several potential speciation drivers.</p

Development and characterization of 35 single nucleotide polymorphism markers for the brown alga Fucus vesiculosus

We characterized 35 single nucleotide polymorphism (SNP) markers for the brown alga Fucus vesiculosus. Based on existing Fucus Expressed Sequence Tag libraries for heat and desiccation-stressed tissue, SNPs were developed and confirmed by re-sequencing cDNA from a diverse panel of individuals. SNP loci were genotyped using the SEQUENOM single base extension iPLEXTM system for multiplex assays on the MassARRAY platform, which uses matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) to discriminate allele-specific products. The SNP markers showed a wide range of variability among 16 populations from the south-west of the UK, northern Portugal and Morocco. The analysis of the information provided by these markers will be useful for studying population structure, historical demography and phylogeography of F. vesiculosus. They can also be used for the identification of genes and/or linked genomic regions potentially subject to selection in response to abiotic stressors like temperature extremes and desiccation intensity that vary across habitats and geographical range.Fundação para a Ciência e Tecnologi

Pressurization of some starches compared to heating: Calorimetric, thermo-optical and X-ray examination

Starch suspensions (30%), from pea and corn samples, with amylose (AML) contents ranging from 28% to 75%, were pressurized between 150 and 650 MPa for 30 min at room temperature. Differential scanning calorimetry (DSC), assisted by thermo-optical polarized microscopy (TPM) and X-ray diffractometry (XRD), was used to demonstrate the difference between pressure-gelatinization and heat gelatinization. The higher amylose content made the starch more resistant to pressure-induced gelatinization. Normal corn (28% AML) and pea starches (35% AML) partially gelatinized at 400 MPa and up, however pressurization produced low-quality gels with granular structure. Conversely, high amylose corn starches (55% and 70% AML) did not gelatinize at all (even at 650 MPa), although the starch suspensions underwent slight increases in viscosity. Retrogradation occurred either concurrently or immediately after pressurization as opposed to long-term thermal retrogradation. XRD revealed that a second scan produced vitrification and possible resistant starch formation in gelatinized/gelled starches. © 2008 Elsevier Ltd. All rights reserved.Partial funding from CICYT (Project MAT2004-00496) is acknowledgedPeer Reviewe

Pressurization of some starches compared to heating: Calorimetric, thermo-optical and X-ray examination

Starch suspensions (30%), from pea and corn samples, with amylose (AML) contents ranging from 28% to 75%, were pressurized between 150 and 650 MPa for 30 min at room temperature. Differential scanning calorimetry (DSC), assisted by thermo-optical polarized microscopy (TPM) and X-ray diffractometry (XRD), was used to demonstrate the difference between pressure-gelatinization and heat gelatinization. The higher amylose content made the starch more resistant to pressure-induced gelatinization. Normal corn (28% AML) and pea starches (35% AML) partially gelatinized at 400 MPa and up, however pressurization produced low-quality gels with granular structure. Conversely, high amylose corn starches (55% and 70% AML) did not gelatinize at all (even at 650 MPa), although the starch suspensions underwent slight increases in viscosity. Retrogradation occurred either concurrently or immediately after pressurization as opposed to long-term thermal retrogradation. XRD revealed that a second scan produced vitrification and possible resistant starch formation in gelatinized/gelled starches. © 2008 Elsevier Ltd. All rights reserved.Partial funding from CICYT (Project MAT2004-00496) is acknowledgedPeer Reviewe

The lab In A box: A take-out practical experience for an online invertebrate biology course

Hands-on experience is critical to teaching invertebrate zoology, as students are unfamiliar with many animals and theoretical concepts are sometimes difficult to assimilate. As part of a fully online course, we decided to give students a box of take-home materials so that they could do hands-on work in their homes under the guidance of the teacher or at their own pace following the lecture scripts and presentations. The box contained whole specimens fixed in ethanol for observation and dissection, dried material such as skeletons and shells, and microscope slides. We also included a USB digital microscope to facilitate visualization of details and slides. The experience was very satisfying and proved to be not only a good alternative for mandatory online classes in times of pandemic, but also an interesting resource to supplement face-toface classes

Pines

Pinus is the most important genus within the Family Pinaceae and also within the gymnosperms by the number of species (109 species recognized by Farjon 2001) and by its contribution to forest ecosystems. All pine species are evergreen trees or shrubs. They are widely distributed in the northern hemisphere, from tropical areas to northern areas in America and Eurasia. Their natural range reaches the equator only in Southeast Asia. In Africa, natural occurrences are confined to the Mediterranean basin. Pines grow at various elevations from sea level (not usual in tropical areas) to highlands. Two main regions of diversity are recorded, the most important one in Central America (43 species found in Mexico) and a secondary one in China. Some species have a very wide natural range (e.g., P. ponderosa, P. sylvestris). Pines are adapted to a wide range of ecological conditions: from tropical (e.g., P. merkusii, P. kesiya, P. tropicalis), temperate (e.g., P. pungens, P. thunbergii), and subalpine (e.g., P. albicaulis, P. cembra) to boreal (e.g., P. pumila) climates (Richardson and Rundel 1998, Burdon 2002). They can grow in quite pure stands or in mixed forest with other conifers or broadleaved trees. Some species are especially adapted to forest fires, e.g., P. banksiana, in which fire is virtually essential for cone opening and seed dispersal. They can grow in arid conditions, on alluvial plain soils, on sandy soils, on rocky soils, or on marsh soils. Trees of some species can have a very long life as in P. longaeva (more than 3,000 years)