From critters to cancers: bridging comparative and clinical research on oxygen sensing, HIF signaling, and adaptations towards hypoxia.

The objective of this symposium at the First International Congress of Respiratory Biology (ICRB) was to enhance communication between comparative biologists and cancer researchers working on O(2) sensing via the HIF pathway. Representatives from both camps came together on August 13-16, 2006, in Bonn, Germany, to discuss molecular adaptations that occur after cells have been challenged by a reduced (hypoxia) or completely absent (anoxia) supply of oxygen. This brief "critters-to-cancer" survey discusses current projects and new directions aimed at improving understanding of hypoxic signaling and developing therapeutic interventions.

Recruitment limitation in Dungeness crab populations is driven by variation in atmospheric forcing.

Ecologists have long debated the relative importance of biotic interactions vs. abiotic forces on the population dynamics of both marine and terrestrial organisms. Investigation of stock size in Dungeness crab (Cancer magister) is a classic example of this debate.

Heat-shock response of the upper intertidal barnacle Balanus glandula: thermal stress and acclimation.

In the intertidal zone in the Pacific Northwest, body temperatures of sessile marine organisms can reach 35 degrees C for an extended time during low tide, resulting in potential physiological stress. We used immunochemical assays to examine the effects of thermal stress on endogenous Hsp70 levels in the intertidal barnacle Balanus glandula. After thermal stress, endogenous Hsp70 levels did not increase above control levels in B.

Crustacean hemocyanin gene family and microarray studies of expression change during eco-physiological stress.

Proteins in the arthropod hemocyanin gene family are involved in major physiological processes, including aerobic respiration, the innate immune response, and molting. Members of this family, hemocyanin, cryptocyanin, and phenoloxidase, are multisubunit molecules that assemble into hexamers and higher aggregates. The hemocyanin hexamers show species-specific subunit heterogeneity.

Linking stages of life history: How larval quality translates into juvenile performance for an intertidal barnacle (Balanus glandula).

Many marine invertebrates with complex life cycles produce planktonic larvae that experience environmental conditions different from those encountered by adults. Factors such as temperature and food, known to impact the larval period, can also affect larval size and consequently the size of newly settled juveniles. After documenting natural variation in the size of cyprids (the final larval stage) of the barnacle Balanus glandula, we experimentally manipulated temperature and food given to larvae to produce cyprids of differing sizes but within the size range of cyprids found in the field.

Offspring size effects mediate competitive interactions in a colonial marine invertebrate.

Over the past 30 years, numerous attempts to understand the relationship between offspring size and fitness have been made, and it has become clear that this critical relationship is strongly affected by environmental heterogeneity. For marine invertebrates, there has been a long-standing interest in the evolution of offspring size, but there have been very few empirical and theoretical examinations of post-metamorphic offspring size effects, and almost none have considered the effect of environmental heterogeneity on the offspring size/fitness relationship. We investigated the post-metamorphic effects of offspring size in the field for the colonial marine invertebrate Botrylloides violaceus.

Functional and phylogenetic analyses of phenoloxidases from brachyuran (Cancer magister) and branchiopod (Artemia franciscana, Triops longicaudatus) crustaceans.

Arthropod phenoloxidases catalyze the melanization and sclerotization of the new postmolt exoskeleton, and they function in the immune response. Hemocyanin, phylogenetically related to phenoloxidase, can function as a phenoloxidase under certain conditions. We investigated the relative contributions of hemocyte phenoloxidase and hemocyanin in the brachyuran crab Cancer magister, using the physiological ratio at which they occur in the hemolymph, and found that hemocyte phenoloxidase has higher activity.

Evolution of novel functions: cryptocyanin helps build new exoskeleton in Cancer magister.

Hemocyanin, the blue blood protein of many arthropods and molluscs, reversibly binds oxygen at its highly conserved copper-oxygen-binding sites and supplies tissues with oxygen. Cryptocyanin, closely related structurally and phylogenetically to arthropod hemocyanin, lacks several of the six critical copper-binding histidines, however, and has lost the ability to bind oxygen. Despite this loss of function, cryptocyanin continues to be synthesized, an indication that it has been exploited to carry out new functions.

Macroevolutionary consequences of developmental mode in temnopleurid echinoids from the Tertiary of southern Australia.

Taxonomic revision and cladistic analysis of a morphological dataset for Australian Tertiary temnopleurids resolve the phylogeny of the group and allow the testing of a series of hypotheses about the evolution of larval development and consequences of changes in development. Australian Tertiary temnopleurids encompass all three major developmental types found in marine invertebrates (planktotrophy, lecithotrophy, and brooding). Planktotrophy is plesiomorphic for this clade, and nonplanktotrophic larval development evolved independently at least three times during the Tertiary.

Phylogeny and evolution of developmental mode in temnopleurid echinoids.

The phylogenetic relationships of 24 nominal species of temnopleurid echinoid were established using molecular and morphological data sets. The analysis combined sequence data from mitochondrial 16S rRNA and cytochrome c oxidase subunit I genes and the nuclear 18S-like small subunit rRNA gene with morphological data concerning coronal, lantern, spine, and pedicellarial traits. All four data sets contain similar phylogenetic information, although each provides support at a different taxonomic level.

Ontogeny of decapod crustacean hemocyanin: effects of temperature and nutrition.

Hemocyanin is present throughout the decapod crustacean's life, usually as one-hexamer and two-hexamer oligomers. Hemocyanins of some decapod crustaceans undergo changes in subunit composition and oxygen affinity during development. Maternal hemocyanin is taken up from the hemolymph via endocytosis by the oocyte.

Respecified larval proleg and body wall muscles circulate hemolymph in developing wings of Manduca sexta pupae.

Most larval external muscles in Manduca sexta degenerate at pupation, with the exception of the accessory planta retractor muscles (APRMs) in proleg-bearing abdominal segment 3 and their homologs in non-proleg-bearing abdominal segment 2. In pupae, these APRMs exhibit a rhythmic 'pupal motor pattern' in which all four muscles contract synchronously at approximately 4 s intervals for long bouts, without externally visible movements. On the basis of indirect evidence, it was proposed previously that APRM contractions during the pupal motor pattern circulate hemolymph in the developing wings and legs.

Cryptocyanin, a crustacean molting protein: evolutionary link with arthropod hemocyanins and insect hexamerins.

Cryptocyanin, a copper-free hexameric protein in crab (Cancer magister) hemolymph, has been characterized and the amino acid sequence has been deduced from its cDNA. It is markedly similar in sequence, size, and structure to hemocyanin, the copper-containing oxygen-transport protein found in many arthropods. Cryptocyanin does not bind oxygen, however, and lacks three of the six highly conserved copper-binding histidine residues of hemocyanin.

Functional adaptations of oxygen-transport proteins.

Oxygen-transport proteins are multisubunit, circulating molecules that provide an efficient supply of oxygen to metabolically active metazoans. Hemoglobins, hemerythrins and hemocyanins have evolved in both structural and functional diversity and exhibit functional repertoires beyond that of simple, monomeric tissue myoglobins. Their phylogenetic distribution is intriguing, especially with respect to those organisms that express more than one type of oxygen-transport protein.

cDNA cloning of a developmentally regulated hemocyanin subunit in the crustacean Cancer magister and phylogenetic analysis of the hemocyanin gene family.

The complete cDNA sequence and protein reading frame of a developmentally regulated hemocyanin subunit in the Dungeness crab (Cancer magister) is presented. The protein sequence is aligned with 18 potentially homologous hemocyanin-type proteins displaying apparent sequence similarities. Functional domains are identified, and a comparison of predicted hydrophilicities, surface probabilities, and regional backbone flexibilities provides evidence for a remarkable degree of structural conservation among the proteins surveyed.

Developmental changes in hemocyanin expression in the Dungeness crab, Cancer magister.

The copper-based respiratory protein hemocyanin undergoes a developmental shift in subunit composition and function analogous to that seen in many hemoglobins. We studied hemocyanin gene expression in the Dungeness crab (Cancer magister) by Northern blot analysis. Animals were raised under controlled conditions, and total RNA was isolated from 13 developmental stages as well as from six tissue types in the adult animal.