A comparison of filtration rates among pelagic tunicates using kinematic measurements

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Marine Biology 157 (2010): 755-764, doi:10.1007/s00227-009-1359-y.Salps have higher filtration rates than most other holoplankton, and are capable of packaging and exporting primary production from surface waters. A method of kinematic analysis was employed to accurately measure salp feeding rates. The data were then used to explain how diverse body morphologies and swimming motions among species and lifecycle stages influence salp feeding performance. We selected five species, representing a range of morphologies and swimming styles, and used digitized outlines from video frames to measure body-shape change during a pulse cycle. Time-varying body volume was then calculated from the digitized salp outlines to estimate the amount of fluid passing through the filtering mesh. This non-invasive method produced higher feeding rates than other methods and revealed that body volume, pulse frequency and degree of contraction are important factors for determining volume filtered. Each species possessed a unique combination of these three characteristics that resulted in comparable filtration (range: 0.44 - 15.33 ml s-1) and normalized filtration rates (range: 0.21 – 1.27 s-1) across species. The convergence of different species with diverse morphologies on similar normalized filtration suggests a tendency towards a flow optimum.This work was supported by NSF project OCE-0647723

STAGES IN THE ORIGIN OF VERTEBRATES: ANALYSIS BY MEANS OF SCENARIOS

Vertebrates lack an epidermal nerve plexus. This feature is common to many invertebrates from which vertebrates differ by an extensive set of shared-derived characters (synapomorphies) derived from the neural crest and epidermal neurogenic placodes. Hence, the hypothesis that the developmental precursor of the epidermal nerve plexus may be homologous to the neural crest and epidermal neurogenic placodes. This account attempts to generate a nested set of scenarios for the prevertebrate-vertebrate transition, associating a presumed sequence of behavioural and environmental changes with the observed phenotypic ones. Toward this end, it integrates morphological, developmental, functional (physiological/behavioural) and some ecological data, as many phenotypic shifts apparently involved associated transitions in several aspects of the animals. The scenarios deal with the origin of embryonic and adult tissues and such major organs as the notochord, the CNS, gills and kidneys and propose a sequence of associated changes. Alternative scenarios are stated as the evidence often remains insufficient for decision. The analysis points to gaps in comprehension of the biology of the animals and therefore suggests further research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72629/1/j.1469-185X.1989.tb00471.x.pd

Peptide and Peptide-Like Modulators of 20S Proteasome Enzymatic Activity in Cancer Cells

The involvement of the ubiquitin–proteasome pathway in the degradation of critical intracellular regulatory proteins suggested a few years ago the potential use of proteasome inhibitors as novel therapeutic agents being applicable in many different disease indications, and in particular for cancer therapy. This article reviews recent salient medicinal chemistry achievements in the design, synthesis, and biological characterization of both synthetic and natural peptide-like proteasome inhibitors, updating recent reviews on this class of agents. As shown herein, different compound classes are capable of modulating the subunit-specific proteolytic activities of the 20S proteasome in ways not previously possible, and one of them, bortezomib, has provided proof-of-concept for this therapeutic approach in cancer clinical settings

Plastid phylogenomics resolves ambiguous relationships within the orchid family and provides a solid timeframe for biogeography and macroevolution

Recent phylogenomic analyses based on the maternally inherited plastid organelle have enlightened evolutionary relationships between the subfamilies of Orchidaceae and most of the tribes. However, uncertainty remains within several subtribes and genera for which phylogenetic relationships have not ever been tested in a phylogenomic context. To address these knowledge-gaps, we here provide the most extensively sampled analysis of the orchid family to date, based on 78 plastid coding genes representing 264 species, 117 genera, 18 tribes and 28 subtribes. Divergence times are also provided as inferred from strict and relaxed molecular clocks and birth–death tree models. Our taxon sampling includes 51 newly sequenced plastid genomes produced by a genome skimming approach. We focus our sampling efforts on previously unplaced clades within tribes Cymbidieae and Epidendreae. Our results confirmed phylogenetic relationships in Orchidaceae as recovered in previous studies, most of which were recovered with maximum support (209 of the 262 tree branches). We provide for the first time a clear phylogenetic placement for Codonorchideae within subfamily Orchidoideae, and Podochilieae and Collabieae within subfamily Epidendroideae. We also identify relationships that have been persistently problematic across multiple studies, regardless of the different details of sampling and genomic datasets used for phylogenetic reconstructions. Our study provides an expanded, robust temporal phylogenomic framework of the Orchidaceae that paves the way for biogeographical and macroevolutionary studies.Universidad de Costa Rica/[814-B8-257]/UCR/Costa RicaUniversidad de Costa Rica/[814-B6-140]/UCR/Costa RicaIDEA WILD/[]//Estados UnidosSociedad Colombiana de Orquideología/[]/SCO/ColombiaFundação de Amparo à Pesquisa do Estado de São Paulo/[11/08308-9]/FAPESP/BrasilFundação de Amparo à Pesquisa do Estado de São Paulo/[13/19124-1]/FAPESP/BrasilSwiss Orchid Foundation/[]//SuizaRoyal Botanic Gardens, Kew/[]//InglaterraSwedish Research Council/[2019-05191]//SueciaSwedish Foundation for Strategic Research/[FFL15-0196]/SSF/SueciaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Jardín Botánico Lankester (JBL

Transient up- and down-regulation of expression of myosin light chain 2 and myostatin mRNA mark the changes from stratified hyperplasia to muscle fiber hypertrophy in larvae of gilthead sea bream (Sparus aurata L.)

Hyperplasia and hypertrophy are the two mechanisms by which muscle develops and grows. We study these two mechanisms, during the early development of white muscle in Sparus aurata, by means of histology and the expression of structural and regulatory genes. A clear stage of stratified hyperplasia was identified early in the development of gilthead sea bream but ceased by 35 dph when hypertrophy took over. Mosaic recruitment of new white fibers began as soon as 60 dph. The genes mlc2a and mlc2b were expressed at various levels during the main phases of hyperplasia and hypertrophy. The genes myog and mlc2a were significantly up-regulated during the intensive stratified formation of new fibers and their expression was significantly correlated. Expression of mstn1 and igf1 increased at 35 dph, appeared to regulate the hyperplasia-to-hypertrophy transition, and may have stimulated the expression of mlc2a, mlc2b and col1a1 at the onset of mosaic hyperplasia. The up-regulation of mstn1 at transitional phases in muscle development indicates a dual regulatory role of myostatin in fish larval muscle growth

AEROBIC AND ANAEROBIC SCALING IN FISH

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75506/1/j.1469-185X.1991.tb01134.x.pd

Multifaceted roles of GSK-3 and Wnt/β-catenin in hematopoiesis and leukemogenesis: opportunities for therapeutic intervention

Glycogen synthase kinase-3 (GSK-3) is well documented to participate in a complex array of critical cellular processes. It was initially identified in rat skeletal muscle as a serine/threonine kinase that phosphorylated and inactivated glycogen synthase. This versatile protein is involved in numerous signaling pathways that influence metabolism, embryogenesis, differentiation, migration, cell cycle progression and survival. Recently, GSK-3 has been implicated in leukemia stem cell pathophysiology and may be an appropriate target for its eradication. In this review, we will discuss the roles that GSK-3 plays in hematopoiesis and leukemogenesis as how this pivotal kinase can interact with multiple signaling pathways such as: Wnt/β-catenin, phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homolog (PTEN)/Akt/mammalian target of rapamycin (mTOR), Ras/Raf/MEK/extracellular signal-regulated kinase (ERK), Notch and others. Moreover, we will discuss how targeting GSK-3 and these other pathways can improve leukemia therapy and may overcome therapeutic resistance. In summary, GSK-3 is a crucial regulatory kinase interacting with multiple pathways to control various physiological processes, as well as leukemia stem cells, leukemia progression and therapeutic resistance. GSK-3 and Wnt are clearly intriguing therapeutic targets