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Cellulose Synthase (Cesa) Genes In The Green Alga Mesotaenium Caldariorum, Alison W. Roberts, Eric M. Roberts, Deborah P. Delmer

Biological Sciences Faculty Publications

Cellulose, a microfibrillar polysaccharide consisting of bundles of β-1,4-glucans chains, is a major component of plant and most algal cell walls and is also synthesized by some prokaryotes. Seed plants and bacteria differ in the structures of their membrane terminal complexes that make cellulose and, in turn, control the dimensions of the microfibrils produced. They also differ in the domain structures of their CesA gene products (the catalytic subunit of cellulose synthase), which have been localized to terminal complexes and appear to help maintain terminal complex structure. Terminal complex structures in algae range from rosettes (plant-like) to linear forms (bacterium-like). …

A Simple Method For Estimating Larval Supply In Reef Fishes And A Preliminary Test Of Population Limitation By Larval Delivery In The Kelp Bass Paralabrax Clathratus, Mark A. Steele, John C. Malone, Amy M. Findlay, Mark H. Carr, Graham E. Forrester

Biological Sciences Faculty Publications

This paper describes a method for estimating larval supply of a temperate reef fish, the kelp bass Paralabrax clathratus, that is simple, inexpensive, requires relatively low effort, and integrates larval supply over time. Using this method, we sampled larval supply concurrently at 4 sites spread over about 35 km for nearly an entire settlement season. With these data and visual estimates of recruitment (the density of young-of-the-year after the end of the settlement season), we tested the hypothesis that spatial patterns in recruitment were set by larval supply. This hypothesis was rejected: kelp bass recruitment to the 4 sites …

Trace Elements In Otoliths Indicate The Use Of Open-Coast Versus Bay Nursery Habitats By Juvenile California Halibut, Graham E. Forrester, Stephen E. Swearer

Biological Sciences Faculty Publications

Many coastal fishes use inshore nursery habitats as juveniles, but it is often difficult to define which nursery areas supply most recruits to adult populations. We tested whether trace element concentrations in otoliths can be used to identify which of 2 nursery habitats (bays or shallow open coast) were occupied by juvenile California halibut. Juveniles from bays in 1998 had concentrations of Cu and Pb in their otoliths that were higher than those in open coast juveniles of the same year. This broad-scale difference between bay and open coast juveniles remained intact when bay juveniles from 1994 to 1997 were …

Silkworm Genomics - Progress And Prospects, J. Nagaraju, Marian R. Goldsmith

Biological Sciences Faculty Publications

The biology and genetics of silkworm, Bombyx mori, is the most advanced of any lepidopteran species. Its rich repertoire of genetic resources and potential applications in sericulture and as a model for other Lepidoptera led to the initiation of genomics research. During the past decade much effort has been made in the areas of marker development, and molecular maps have been constructed in standard strains with the use of RFLPs, RAPDs, ISSRs, STSs, and microsatellites. The potential applications of molecular markers and linkage maps include stock identification, Marker Assisted Selection (MAS), identification of Quantitative Trait Loci (QTL), and, ultimately, …

Function Of The Heterocercal Tail In Sharks: Quantitative Wake Dynamics During Steady Horizontal Swimming And Vertical Maneuvering, C. D. Wilga, G. V. Lauder

Biological Sciences Faculty Publications

The function of the heterocercal tail in sharks has long been debated in the literature. Previous kinematic data have supported the classical theory which proposes that the beating of the heterocercal caudal fin during steady horizontal locomotion pushes posteroventrally on the water, generating a reactive force directed anterodorsally and causing rotation around the center of mass. An alternative model suggests that the heterocercal shark tail functions to direct reaction forces through the center of mass. In this paper, we quantify the function of the tail in two species of shark and compare shark tail function with previous hydrodynamic data on …

Hybridization Diversity Of The Chorion Multigene Families Of Bombyx Mandarina With Reference To Several Genetic Stocks Of Bombyx Mori, Bungo Sakaguchi, Marian R. Goldsmith, Nikolaus A. Spoerel, Yumiko Nakajimai, Yutaka Kawaguchi, Katsumi Koga

Biological Sciences Faculty Publications

Genomic Southern blotting analyses of Bombyx mori and B. mandarina were performed with the 5′-exons or 5′-flanking sequences of two members of genes A/B.L11 and A/B.L12. They represent multigene families encoding chorion proteins that are expressed in the middle period of choriogenesis. Many bands cross-hybridized with the probes in B. mandarina and in different strains and races of B. mori, supporting the idea that the middle chorion multigene families have remained essentially the same in the two species. Both the exon and the 5′-flanking probes exhibited similar patterns within the European stocks of B. mori, indicating that the examined …

Evolution Of Upper Jaw Protrusion Mechanisms In Elasmobranchs, Cheryl Wilga, Robert E. Hueter, Peter C. Wainwright, Philip J. Motta

Biological Sciences Faculty Publications

Upper jaw protrusion is a prominent component of the feeding mechanism in most elasmobranchs and has received considerable attention over the years. In this paper, we review what is known of muscle activity during prey capture in elasmobranchs, particularly that of upper jaw protrusion, and evaluate the extent to which functional modifications have evolved through changes in anatomy or patterns of muscle activity. To date, motor activity during feeding has been documented in only four species of elasmobranchs, although they represent the three major elasmobranch groups: Galea (typical sharks); Squalea (dogfish sharks); and Batoidea (skates and rays). Our efforts show …

Role Of Ca2+ In Excitation-Contraction Coupling In Echinoderm Muscle: Comparison With Role In Other Tissues, Robert B. Hill

Biological Sciences Faculty Publications

The longitudinal muscle of the body wall of Isostichopus badionotus may be considered a model for excitation-contraction coupling in echinoderm muscle. Other echinoderm muscles are reviewed by comparison with the model. Echinoderm muscle is also of interest as a model for ‘mutable collagenous tissue’; however, in that tissue, Ca²⁺ has been proposed to function both in living control systems and in regulation of non-living interstitial substance.

Durophagy In Sharks: Feeding Mechanics Of The Hammerhead Sphyrna Tiburo, Cheryl D. Wilga, Philip J. Motta

Biological Sciences Faculty Publications

This study investigates the motor pattern and head movements during feeding of a durophagus shark, the bonnethead Sphyrna tiburo, using electromyography and simultaneous high-speed video. Sphyrna tiburo feeds almost exclusively on hard-shelled crabs, with shrimp and fish taken occasionally. It captures crabs by ram feeding, then processes or reduces the prey by crushing it between molariform teeth, finally transporting the prey by suction for swallowing. The prey-crushing mechanism is distinct from that of ram or bite capture and suction transport. This crushing mechanism is accomplished by altering the duration of jaw adductor muscle activity and modifying jaw kinematics by …

Influence Of Size And Delayed Settlement On The Recapture Rate Of Newly Settled American Lobsters Homarus Americanus, Mary-Jane James-Pirri, J. Stanley Cobb

Biological Sciences Faculty Publications

Postlarval American lobsters Homarus americanus exhibit variation in size at settlement and timing of settlement but it is not known if this variability influences future survival. The ability to track the fate of individual newly settled lobsters has become possible with the advent of micro-wire tags. In this study micro-wire tags were used to identify individual postlarval and fifth instar lobsters that were released into the field and then recaptured 1 wk later. The influence of size at settlement and timing of settlement on subsequent recapture rate were determined. The overall recapture rate for tagged postlarvae and fifth instars was …

Characterization Of Early Follicular Cdna Library Suggests Evidence For Genetic Polymorphisms In The Inbred Strain C108 Of Bombyx Mori, Marian R. Goldsmith, David R. Mills

Biological Sciences Faculty Publications

Recent work towards the completion of a saturated molecular genetic linkage map for the lepidopteran silkworm, Bombyx mori (n=28), has provided evidence for existing polymorphisms in the inbred strain C108. Two inbred parental strains, p50 and C108, were crossed to produce the F1 (P/C) hybrid offspring. The populations used in this project were comprised of a combination of 29 F2 (F1 x F1) and 31 reciprocal backcross (P/C x C/C, P/C x P/P) progeny. All restriction fragment length polymorphisms (RFLPs) for the initial analysis were hybridized with anonymous probes derived from a random early follicular cDNA (Rcf) library from Bombyx. …

Three-Dimensional Kinematics And Wake Structure Of The Pectoral Fins During Locomotion In Leopard Sharks Triakis Semifasciata, C. D. Wilga, George V. Lauder

Biological Sciences Faculty Publications

The classical theory of locomotion in sharks proposes that shark pectoral fins are oriented to generate lift forces that balance the moment produced by the oscillating heterocercal tail. Accordingly, previous studies of shark locomotion have used fixed-wing aircraft as a model assuming that sharks have similar stability and control mechanisms. However, unlike airplanes, sharks are propelled by undulations of the body and tail and have considerable control of pectoral fin motion. In this paper, we use a new approach to examine the function of the pectoral fins of leopard sharks, Triakis semifasciata, during steady horizontal swimming at speeds of …

Locomotion In Sturgeon: Function Of The Pectoral Fins, C. D. Wilga, G. V. Lauder

Biological Sciences Faculty Publications

Pectoral fins are one of the major features of locomotor design in ray-finned fishes and exhibit a well-documented phylogenetic transition from basal to derived clades. In percomorph fishes, the pectoral fins are often used to generate propulsive force via oscillatory movements, and pectoral fin propulsion in this relatively derived clade has been analyzed extensively. However, in the plesiomorphic pectoral fin condition, exemplified by sturgeon, pectoral fins extend laterally from the body in a generally horizontal orientation, have been assumed to generate lift to balance lift forces and moments produced by the heterocercal tail, and are not oscillated to generate propulsive …

Metamorphosis In The Summer Flounder Paralichthys Dentatus: Changes In Gill Mitochondria-Rich Cells, Alex M. Schreiber, Jennifer Specker

Biological Sciences Faculty Publications

Salinity tolerance changes during larval development and metamorphosis in the summer flounder (Paralichthys dentatus) and other teleosts. The physiological mechanisms responsible for osmoregulation during these early stages of development are not well understood. This study characterized changes in ultrastructure, intracellular membranes and immunoreactive Na⁺/K⁺-ATPase of mitochondria-rich cells (MRCs) in the gills of summer flounder during metamorphosis. Gill ultrastructure at the start of metamorphosis revealed only one type of MRC, which had weak reactivity to osmium and lacked a well-defined apical pit. In juveniles, two types of MRCs were observed: light-staining MRCs (LMRCs) with weak reactivity to …

Flight Of The Vampire: Ontogenetic Gait-Transition In Vampyroteuthis Infernalis (Cephalopoda: Vampyromorpha), Brad A. Seibel, Erik V. Thuesen, James J. Childress

Biological Sciences Faculty Publications

Vampyroteuthis infernalis is a cosmopolitan cephalopod that lives in the oxygen minimum layer between 600 and 800 m depth. Morphometric and physiological studies have indicated that V. infernalis has little capacity for jet propulsion and has the lowest metabolic rate ever measured for a cephalopod. Because fin swimming is inherently more efficient than jet propulsion, some of the reduction in energy usage relative to other cephalopods may result from the use of fins as the primary means of propulsion. V. infernalis undergoes a rapid metamorphosis which consists of changes in the position, size and shape of the fins. This …

Life At Stable Low Oxygen Levels: Adaptations Of Animals To Oceanic Oxygen Minimum Layers, James J. Childress, Brad A. Seibel

Biological Sciences Faculty Publications

Zones of minimum oxygen level are found at intermediate depths in most of the world’s oceans and, although the oxygen partial pressure in some of these ‘oxygen minimum layers’ is only a fraction of a kilopascal, populations of pelagic metazoans exist there. These oxygen minimum layers are areas of the water column and the associated benthos with stable conditions of continuously low oxygen level and low temperature at intermediate depths (400–1000 m depth) over vast areas. Off California, where PO₂at the oxygen minimum is 0.8 kPa, there are abundant populations of animals both in the water column …

Flight Without Horizon References In European Starlings, Robert G. Moyle, Frank H. Heppner

Biological Sciences Faculty Publications

No abstract provided.

Conservation And Variation In The Feeding Mechanism Of The Spiny Dogfish Squalus Acanthias, Cheryl D. Wilga, Philip J. Motta

Biological Sciences Faculty Publications

Changes in the feeding mechanism with feeding behavior were investigated using high-speed video and electromyography to examine the kinematics and motor pattern of prey capture, manipulation and transport in the spiny dogfish Squalus acanthias (Squalidae: Squaliformes). In this study, Squalus acanthias used both suction and ram behaviors to capture and manipulate prey, while only suction was used to transport prey. The basic kinematic feeding sequence observed in other aquatic-feeding lower vertebrates is conserved in the spiny dogfish. Prey capture, bite manipulation and suction transport events are characterized by a common pattern of head movements and motor activity, but are distinguishable …

Feeding Mechanism Of The Atlantic Guitarfish Rhinobatos Lentiginosus: Modulation Of Kinematic And Motor Activity, Cheryl D. Wilga, Philip J. Motta

Biological Sciences Faculty Publications

The kinematics and muscle activity pattern of the head and jaws during feeding in the Atlantic guitarfish Rhinobatos lentiginosus are described and quantified using high-speed video and electromyography to test hypotheses regarding the conservation and modulation of the feeding mechanism. Prey is captured by the guitarfish using suction. Suction capture, bite manipulation and suction transport behaviors in the guitarfish are similar to one another in the relative sequence of kinematic and motor activity, but can be distinguished from one another by variation in absolute muscle activation time, in the presence or absence of muscle activity and in the duration of …

Growth Rates Of Planktonic And Newly Settled American Lobsters Homarusamericanus, Mary-Jane James-Pirri, J. Stanley Cobb

Biological Sciences Faculty Publications

Growth rates, as estimated by the RNA:DNA ratio, were determined for planktonic postlarvae and for recaptured and wild newly settled benthic stages (fifth and sixth instars) of the American lobster Homarus americanus. The mean growth rate of planktonic postlarvae in 1994 was 0.522 ± 0.247 mg protein d^-1. This was significantly higher than planktonic growth rates observed in 1991 (0.449 ± 0.121 mg protein d^-1) but not in 1992 (0.460 ± 0.144 mg protein d^-1). The percentage of poorly nourished planktonic postlarvae, those with growth rates <0.220 mg protein d^-1, ranged from 3 to 13% …

Effect Of Wind And Tidal Advection On Distribution Patterns Of Rock Crab Cancer Irroratus Megalopae In Block Island Sound, Rhode Island, Michael Clancy, J. Stanley Cobb

Biological Sciences Faculty Publications

The planktonic period of benthic marine invertebrates can significantly affect distribution patterns of benthic juveniles. In this paper we address the relationship between advection and the subsequent abundance of planktonic megalopae of the rock crab Cancer irroratus in Block Island Sound, Rhode Island (USA), over an 8 yr period. At small scales (several meters distance with samples taken simultaneously), megalopae were found to be similarly distributed; at larger temporal (tens of minutes) and spatial scales (hundreds of meters) megalopae were very patchy, which indicates a complex, highly variable pattern of abundance typical of planktonic systems. Using the receptor-mode trajectory capability …

Evidence For Cholinergic Inhibitory And Serotonergic Excitatory Neuromuscular Transmission In The Heart Of The Bivalve Mercenaria Mercenaria, Kiyoaki Kuwasawa, Robert A. Hill

Biological Sciences Faculty Publications

The heart of Mercenaria mercenaria is innervated bilaterally at the atria. A pair of cardiac nerves arise as a branch of the cerebro-visceral connective and run to the posterior end of the junction between each atrium and its efferent branchial vessel. Innervation evidently spreads over the heart, since both inhibitory and excitatory junctional potentials (IJPs and EJPs) can be recorded from the atria, the atrio-ventricular (AV) valve or the ventricle.

The cardiac nerves contain inhibitory and excitatory axons. Neural stimulation can cause increases in the frequency or amplitude of beating, depending on the strength and frequency of stimulation. Electrical stimulation …

Strategies For Life In Flow: Tenacity, Morphometry, And Probability Of Dislodgment Of Two Mytilus Species, Emily C. Bell, John M. Gosline

Biological Sciences Faculty Publications

The attachment strength of sessile intertidal organisms is continuously challenged by the hydrodynamic forces generated by breaking waves. This study explores mechanisms by which the attachment strength, or tenacity, can vary for one of the dominant competitors for space in this environment, the marine mussel. Tenacity was measured for 2 co-existing mussel species, Mytilus californianus and Mytilus trossulus, either solitary or within a bed (= bed mussels). The tenacity of M. californianus was higher than M. trossulus, due to increased byssal thread thickness, and the tenacity of solitary mussels was higher than bed mussels, due to the presence …

The Auxin Transport Inhibitor N-(1-Naphthyl)Phthalamic Acid Elicits Pseudonodules On Nonnodulating Mutants Of White Sweetclover, C. Wu, R. Dickstein, A. J. Cary, J. H. Norris

Biological Sciences Faculty Publications

The collection of symbiotic (sym) mutants of white sweetclover (Melilotus alba Desr.) provides a developmental sequence of mutants blocked early in infection or nodule organogenesis. Mutant phenotypes include non-nodulating mutants that exhibit root-hair deformations in response to Rhizobium meliloti, mutants that form ineffective nodules lacking infection threads, and mutants that form infection threads and ineffective nodules. Mutant alleles from both the sym-1 and the sym-3 loci exhibited a non-nodulating phenotype in response to R. meliloti, although one allele in the sym-1 locus formed ineffective nodules at a low frequency. Spot-inoculation experiments on a non-nodulating allele in the sym-3 locus indicated …

Timing Of Metamorphosis In A Freshwater Crustacean: Comparison With Anuran Models, Saran Twombly

Biological Sciences Faculty Publications

Many crustaceans have complex life cycles characterized by a metamorphosis, yet variation in metamorphic traits, and the causes and consequences of this variation, have rarely been examined. Food concentrations were changed during specific larval stages of the freshwater copepod Mesocyclops edax Forbes (Copepoda: Cyclopoida) to examine whether age and size at metamorphosis remain flexible or become fixed during the larval period. Results were compared to predictions of both flexible (the Wilbur—Collins model) and fixed (Leips—Travis model) rate models for the timing of amphibian metamorphosis. Age and size at metamorphosis were variable in all treatments, and age was always more variable …