Physical effects of habitat-forming species override latitudinal trends in temperature.

Latitudinal and elevational temperature gradients (LTG and ETG) play central roles in biogeographical theory, underpinning predictions of large-scale patterns in organismal thermal stress, species' ranges and distributional responses to climate change. Yet an enormous fraction of Earth's taxa live exclusively in habitats where foundation species modify temperatures. We examine little-explored implications of this widespread trend using a classic model system for understanding heat stresses - rocky intertidal shores. Through integrated field measurements and laboratory trials, we demonstrate that thermal buffering by centimetre-thick mussel and seaweed beds eliminates differences in stress-inducing high temperatures and associated mortality risk that would otherwise arise over 14° of latitude and ~ 1 m of shore elevation. These results reveal the extent to which physical effects of habitat-formers can overwhelm broad-scale thermal trends, suggesting a need to re-evaluate climate change predictions for many species. Notably, inhabitant populations may exhibit deceptive resilience to warming until refuge-forming taxa become imperiled.

Persistent spatial structuring of coastal ocean acidification in the California Current System.

The near-term progression of ocean acidification (OA) is projected to bring about sharp changes in the chemistry of coastal upwelling ecosystems. The distribution of OA exposure across these early-impact systems, however, is highly uncertain and limits our understanding of whether and how spatial management actions can be deployed to ameliorate future impacts. Through a novel coastal OA observing network, we have uncovered a remarkably persistent spatial mosaic in the penetration of acidified waters into ecologically-important nearshore habitats across 1,000 km of the California Current Large Marine Ecosystem. In the most severe exposure hotspots, suboptimal conditions for calcifying organisms encompassed up to 56% of the summer season, and were accompanied by some of the lowest and most variable pH environments known for the surface ocean. Persistent refuge areas were also found, highlighting new opportunities for local adaptation to address the global challenge of OA in productive coastal systems.

Consequences of transient fluid forces for compliant benthic organisms.

The diversity of form among benthic marine plants and animals on rocky coasts is remarkable. Stiff and strong organisms grow alongside others that are compliant and flimsy. Given the severity of wave action on many shores and thus the potential for the imposition of large hydrodynamic forces, this immediately raises the question of how, from this overall spectrum of designs, flexible and weak organisms survive. A number of explanations have been proposed, most emphasizing one or more of several possible advantages of deformability. Here, we explore quantitatively two of the more common of these explanations: (i) that strength can be traded against extensibility in allowing stretchy organisms to withstand transient wave forces, and (ii) that greater compliance (and thus longer organism response times) allows universally for the amelioration of brief loads. We find that, although these explanations contain kernels of validity and are accurate for a subset of conditions, they are not as general as has often been assumed.

Iontophoretic administration of 2% lidocaine HCl and 1:100,000 epinephrine in humans.

OBJECTIVE: The primary objective was to evaluate the clinical safety and effectiveness of the iontophoretic administration of lidocaine HCl 2% and epinephrine 1:100,000 to induce local dermal anesthesia before intravenous (i.v.) cannulation. DESIGN: Section I: Open, nonblinded. Section II: Randomized, double-blind, placebo-controlled. SETTING: Section I: Healthy adult volunteers. Section II: Patients presenting for scheduled outpatient eye surgery. PATIENTS: Section I: Seven healthy adult volunteers. Section II: Forty-four patients requiring i.v. cannulation before scheduled eye surgery. INTERVENTIONS: Section I: Volunteers received iontophoresis of lidocaine HCl 2% with epinephrine 1:100,000 for a total delivery current of 40 mA min. Section II: Patients received iontophoresis for a total delivery current of 40 mA min of lidocaine HCl 2% with epinephrine 1:100,000 (active) or saline (control) immediately before intravenous cannulation with a 20-gauge i.v. catheter. MAJOR OUTCOME MEASURES: Section I: Venous blood plasma lidocaine levels, adverse events associated with iontophoresis. Section II: Patient and investigator assessment of analgesia, patient acceptance of iontophoresis, adverse events associated with iontophoresis. RESULTS: Section I: No detectable levels of lidocaine were identified in any blood plasma sample. Adverse effects were minimal and transitory. Section II: Pain was decreased following lidocaine iontophoresis in comparison with controls, as determined by the patients and investigators. Iontophoresis was well accepted by the patients. Adverse effects were minimal and transitory. CONCLUSIONS: Iontophoresis of lidocaine 2% with 1:100,000 epinephrine for short delivery times does not lead to delivery of clinically important systemic levels of lidocaine in healthy adults. Iontophoresis of lidocaine 2% with 1:100,000 epinephrine provides adequate skin anesthesia for placement of peripheral small-gauge i.v. catheters.

Flow and flexibility. I. Effects Of size, shape and stiffness in determining wave forces on the stipitate kelps eisenia arborea and pterygophora californica

Wave action on exposed rocky coasts can be severe, generating large hydrodynamic forces that have been proposed to constrain the size of intertidal animals and plants. In contrast, flows subtidally are more benign, and organisms, particularly seaweeds, may grow quite large. The large dimensions of these flexible macroalgae allow them to move during much or most of a passing wave cycle, reducing relative water velocities and modifying the forces the plants must endure. The consequences of such wave-induced motion are explored for the stipitate understory kelps Eisenia arborea and Pterygophora californica using a numerical model that approximates these seaweeds as vertically oriented cantilever beams subjected to lateral hydrodynamic forces acting at their stipe tips. Bending moments and peak stresses induced in the stipes of these species during the passage of waves are calculated as functions of plant size and shape and of water depth and sea state. Model predictions for a subset of conditions are validated against real-time measurements of bending moments acting on a Pterygophora individual in the field. The results suggest that the allometric patterns of growth exhibited by Eisenia and Pterygophora can greatly reduce the stresses generated in the stipes of these plants relative to isometric growth. Low stipe stiffness acts as a general, particularly effective, stress-lowering mechanism. The dynamic swaying associated with this low stiffness can also modulate the magnitudes of peak stresses induced in the stipes of these kelps. In particular, in shallow water under large waves, dynamic loading can substantially increase induced stress, suggesting that plant motion is an important factor affecting the loading regime encountered by these organisms.

Why the urchin lost its spines: hydrodynamic forces and survivorship in three echinoids

Two species of sea urchins (Colobocentrotus atratus and Echinometra mathaei) commonly co-occur on wave-swept intertidal shores in the Indo West Pacific. E. mathaei is a typical spiny urchin and is confined to cavities in the rock. In contrast, C. atratus has an unusual morphology, in which the spines are much reduced, and is found on substrata fully exposed to wave-induced velocities and accelerations. Previous researchers have suggested that spine reduction may therefore be a morphological adaptation to hydrodynamic forces. However, measurement of the drag, lift and accelerational forces on sea urchins show that the adaptive significance of spine reduction is less straightforward than it initially appears. The reduction in drag in C. atratus as compared with that in E. mathaei is to a large extent offset by an increase in lift. Instead, the 'streamlined' morphology of C. atratus seems best adapted to provide a reduction in the force imposed by water acceleration, thereby making it feasible for C. atratus to venture safely into the tumultuous flows of the surf zone.

Characterization of a major late herpes simplex virus type 1 mRNA.

A major, late 6-kilobase (6-kb) mRNa mapping in the large unique region of herpes simplex virus type 1 (HSV-1) was characterized by using two recombinant DNA clones, one containing EcoRI fragment G (0.190 to 0.30 map units) in lambda. WES.B (L. Enquist, M. Madden, P. Schiop-Stansly, and G. Vandl Woude, Science 203:541-544, 1979) and one containing HindIII fragment J (0.181 to 0.259 map units) in pBR322. This 6-kb mRNA had its 3' end to the left of 0.231 on the prototypical arrangement of the HSV-1 genome and was transcribed from right to left. It was bounded on both sides by regions containing a large number of distinct mRNA species, and its 3' end was partially colinear with a 1.5-kb mRNA which encoded a 35,000-dalton polypeptide. The 6-kb mRNA encoded a 155,000-dalton polypeptide which was shown to be the only one of this size detectable by hybrid-arrested translation encoded by late polyadenylated polyribosomal RNA. The S1 nuclease mapping experiments indicated that there were no introns in the coding sequence for this mRNA and that its 3' end mapped approximately 800 nucleotides to the left of the BglII site at 0.231, whereas its 5' end extended very close to the BamHI site at 0.266.

Detailed characterization of the mRNA mapping in the HindIII fragment K region of the herpes simplex virus type 1 genome.

We have isolated as recombinant DNA clones, in the plasmid pBR322, regions of the herpesvirus type 1 genome spanning the region between 0.53 and 0.6 on the prototypical arrangement. This 11,000-base-pair region corresponds to 10% of the large unique region and encodes five major and several minor mRNA species abundant at different times after infection, which range in length from 7 to 1 kilobase. In this report, we have used RNA transfer blots and S1 nuclease digestion of hybrids between viral DNA and polyribosomal RNA to precisely localize (+/- 0.1 kilobase) these mRNA's. Comparison of neutral and alkaline gels of S1 nuclease-digested hybrids indicates no internal introns in the coding sequences of these mRNA's, although noncontiguous leader sequences near (ca. 0.1 kilobase) the 5' ends of any or all mRNA's could not be excluded. The 5' ends of several late mRNA's that are encoded opposite DNA strands map very close to one another, and the 3' ends of a major late and a major early mRNA, which are partially colinear, terminate in the same region. In vitro translation of the viral mRNA's isolated by hybridization with DNA bound to cellulose and fractionation of mRNA species on denaturing agarose gels allowed us to assign specific polypeptide products to each of the mRNA's characterized. Among other results, it was demonstrated unequivocally that two major late mRNA's, which partially overlap, encode the same polypeptide.

Isolation and translation of mRNA encoded by a specific region of the herpes simplex virus type 1 genome.

We have examined in detail the major mRNA species encoded by the region of the herpes simplex virus type 1 genome encoded by HindIII fragment K (0.53-0.59 from the left end of the prototype arrangement of the genome) by using this restriction fragment bound to cellulose as a reagent for isolation of this mRNA. Before viral DNA replication in infected cells (early), a major species of viral mRNA 5.2 kilobases (kb) in length is abundant. After the onset of viral DNA replication (late), four mRNA species are abundant: 7, 5.2, 3.8, and 1.8 kb in size. We have used reverse transcriptase from avian myeloblastosis virus to make DNA complementary to these RNA species and their 3' ends. We have shown by hybridization of this complementary DNA to Southern blots of herpes simplex virus type 1 DNA that the 7-, 5.2-, and 1.8-kb mRNA species have their 3' ends to the right of 0.59 and are at least partially colinear. The 3.8-kb mRNA has a 3' end mapping to the left of the 3' ends of these other species. In vitro translation of HindIII fragment K-specific mRNA in a reticulocyte lysate system yielded three major polypeptide products: 140,000, 122,000, and 54,000 daltons (d). Less prominent species of 86,000 and 65,000 d also were produced. Translation of size-fractionated HindIII fragment K-specific mRNA showed that the 7-, 5.2-, and 3.8-kb mRNA's encoded the 54,000-, 140,000-, and 122,000-d polypeptides, respectively. The 140,000-d polypeptide was the major polypeptide translated using early HindIII fragment K-specific mRNA as a template. The 3.8-kb mRNA also encoded the 86,000-d polypeptide, whereas the 1.8-kb mRNA encoded a polypeptide that was indistinguishable from the 54,000-d polypeptide encoded by the 7-kb mRNA, in addition to the 65,000-d polypeptide. The implications of the data are discussed.