75 research outputs found
Instructional Learning Teams: A Case Study
Changing teacher practices to improve student learning is a challenge. For teachersâ practices to change, faculties within schools must build communities of practice. However, supporting teachersâ collaborative learning within a Professional Learning Team can be an elusive challenge. We found through the Instructional Learning Team (ILT) model of professional development that teachers have a focused model to make effective changes to their practice. ILTs promote school improvement by providing a process through which teachers collaboratively focus on sustained reflection about student learning tasks, instruction, and student work using the Japanese Lesson Study and critiquing their work using Newmannâs (1996) Intellectual Quality framework. We followed two teams of teachers over a semester and qualitatively examined changes in four elements of professional learning: shared ideas and values, focus on student learning, reflective dialogue, and deprivatization of practice. Through the ILT process all four elements of professional learning communities increased. This process of changing practice through examining instructional tasks, practices and student work has a direct impact on helping teachers move toward implementing the Common Core State Standards (CCSS)
The Hidden Sexuality of Alexandrium Minutum: An Example of Overlooked Sex in Dinoflagellates
Dinoflagellates are haploid eukaryotic microalgae in which rapid proliferation causes dense
blooms, with harmful health and economic effects to humans. The proliferation mode is
mainly asexual, as the sexual cycle is believed to be rare and restricted to stressful environmental
conditions. However, sexuality is key to explaining the recurrence of many dinoflagellate
blooms because in many species the fate of the planktonic zygotes (planozygotes)
is the formation of resistant cysts in the seabed (encystment). Nevertheless, recent
research has shown that individually isolated planozygotes in the lab can enter other routes
besides encystment, a behavior of which the relevance has not been explored at the population
level. In this study, using imaging flow cytometry, cell sorting, and Fluorescence In
Situ Hybridization (FISH), we followed DNA content and nuclear changes in a population of
the toxic dinoflagellate Alexandrium minutum that was induced to encystment. Our results
first show that planozygotes behave like a population with an âencystment-independentâ
division cycle, which is light-controlled and follows the same Light:Dark (L:D) pattern as the
cycle governing the haploid mitosis. Resting cyst formation was the fate of just a small fraction
of the planozygotes formed and was restricted to a period of strongly limited nutrient
conditions. The diploid-haploid turnover between L:D cycles was consistent with two-step
meiosis. However, the diel and morphological division pattern of the planozygote division
also suggests mitosis, which would imply that this species is not haplontic, as previously
considered, but biphasic, because individuals could undergo mitotic divisions in both the
sexual (diploid) and the asexual (haploid) phases. We also report incomplete genome duplication
processes. Our work calls for a reconsideration of the dogma of rare sex in
dinoflagellates.VersiĂłn del edito
Researchers combat resurgence of bed bug in behavioral studies and monitor trials
The worldwide resurgence of bed bugs has recently created urban pest challenges in California. Regardless of information source â newspaper, Internet, television, university or government â the message is the same: bed bugs are back, and with a vengeance. Until recently, the pest's longstanding rarity and a historical reliance on pesticide-based management have not encouraged research and public education to develop and make available current information on bed bug biology, detection and control. UC is currently directing comprehensive, collaborative programs of research and education to combat this emerging nuisance and public health threat. Laboratory and field tests were conducted by UC researchers on several commercial bed bug monitors and confirm that additional research is needed to improve the performance of existing monitors and to develop new ones
Phylogenetic placement of environmental sequences using taxonomically reliable databases helps to rigorously assess dinophyte biodiversity in Bavarian lakes (Germany).
1. Reliable determination of organisms is a prerequisite to explore their spatial
and temporal occurrence and to study their evolution, ecology, and dispersal. In
Europe, Bavaria (Germany) provides an excellent study system for research on the
origin and diversification of freshwater organisms including dinophytes, due to
the presence of extensive lake districts and ice age river valleys. Bavarian freshwater
environments are ecologically diverse and range from deep nutrientâpoor
mountain lakes to shallow nutrientârich lakes and ponds.
2. We obtained amplicon sequence data (V4 region of small subunitârRNA, c. 410 bp
long) from environmental samples collected at 11 sites in Upper Bavaria. We
found 186 operational taxonomic units (OTUs) associated with Dinophyceae that
were further classified by means of a phylogenetic placement approach.
3. The maximum likelihood tree inferred from a wellâcurated reference alignment comprised
a systematically representative set of 251 dinophytes, covering the currently
known molecular diversity and OTUs linked to type material if possible. Environmental
OTUs were scattered across the reference tree, but accumulated mostly in freshwater
lineages, with 79% of OTUs placed in either Apocalathium, Ceratium, or Peridinium,
the most frequently encountered taxa in Bavaria based on morphology.
4. Twentyâone Bavarian OTUs showed identical sequences to already known and
vouchered accessions, two of which are linked to type material, namely Palatinus
apiculatus and Theleodinium calcisporum. Particularly within Peridiniaceae, delimitation
of Peridinium species was based on the intraspecific sequence variation.
5. Our approach indicates that highâthroughput sequencing of environmental samples
is effective for reliable determination of dinophyte species in Bavarian lakes.
We further discuss the importance of wellâcurated reference databases that remain
to be developed in the future
Distinct Gene Number-Genome Size Relationships for Eukaryotes and Non-Eukaryotes: Gene Content Estimation for Dinoflagellate Genomes
The ability to predict gene content is highly desirable for characterization of not-yet sequenced genomes like those of dinoflagellates. Using data from completely sequenced and annotated genomes from phylogenetically diverse lineages, we investigated the relationship between gene content and genome size using regression analyses. Distinct relationships between log10-transformed protein-coding gene number (YâČ) versus log10-transformed genome size (XâČ, genome size in kbp) were found for eukaryotes and non-eukaryotes. Eukaryotes best fit a logarithmic model, YâČâ=âln(-46.200+22.678XâČ, whereas non-eukaryotes a linear model, YâČâ=â0.045+0.977XâČ, both with high significance (p<0.001, R2>0.91). Total gene number shows similar trends in both groups to their respective protein coding regressions. The distinct correlations reflect lower and decreasing gene-coding percentages as genome size increases in eukaryotes (82%â1%) compared to higher and relatively stable percentages in prokaryotes and viruses (97%â47%). The eukaryotic regression models project that the smallest dinoflagellate genome (3Ă106 kbp) contains 38,188 protein-coding (40,086 total) genes and the largest (245Ă106 kbp) 87,688 protein-coding (92,013 total) genes, corresponding to 1.8% and 0.05% gene-coding percentages. These estimates do not likely represent extraordinarily high functional diversity of the encoded proteome but rather highly redundant genomes as evidenced by high gene copy numbers documented for various dinoflagellate species
Redefinition of Peridinium lomnickii WoĆoszynska (Dinophyta) by scanning electronmicroscopical survey
Peridinium lomnickii Woloszynska was investigated by scanning electron microscopy with special attention to the importance of development of thecal plate during the life cycle. Different life cycle stages (gymnodinoid-, glenodinoid-, peridinioid) are described on the basis of development of cell wall, presence and development of sutures, appearance of pore and the change of the cell shape. Differences and possible relationships between the three existing varieties of the species are discussed. We suggest that the three varieties of P. lomnickii, P. lomnickii var. lomnickii, P. lomnickii var. wierzejskii and P. lomnickii var. splendida, represent the different life cycle stages of the species. These results and the known ontogenic cycle of dinophyta taxa should be taken into consideration, when a phylogenic tree of the dinophytes is constructed
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