Life Sciences Commons^™

Isolation, Characterization, And Diversity Of Microorganisms From Amber, Raúl J. Cano

Biological Sciences

Retrieval of viable bacteria from fossil material dating from the Oligocene back to the Miocene opens the opportunity to study the evolution of prokaryotes through the evolution of their DNA, their physiology, and their ecology. This unique system in which ancient organisms and their genes may be compared directly, rather than by inference, with modern homologues is without precedent. Clearly, however, confirmation of the fossil origin of such isolates must be made in a manner that would allay reasonable skepticism. Present approaches of verification of authenticity of fossil DNA are either arbitrary or potentially unconvincing, because of their dependence on …

Dietary Iron And Recurrence Of Colorectal Adenomas, Marilyn Tseng, Robert S. Sandler, E. Robert Greenberg, Jack S. Mandel, Robert W. Haile, John A. Baron

Kinesiology and Public Health

Previous research suggests that iron acts as a prooxidant to increase the risk of colorectal neoplasia. This study examined effects of dietary intake of iron on colorectal adenoma recurrence using data from an antioxidant clinical trial. All subjects were free of polyps at study entry but had at least one adenoma removed within the 3 months before enrollment. Follow-up colonoseopies were conducted after 1 and 4 years. Patients who developed one or more adenomatous polyps between years 1 and 4 were classified as cases; all others were controls. Dietary iron intake at baseline and at the end of the study …

Communicating The Role Of Science In Managing Giant Sequoia Groves, Douglas D. Piirto, Robert R. Rogers, Mary C. Bethke

Natural Resources Management and Environmental Sciences

Management of giant sequoia groves has been and continues to be a hotly debated issue. The debate has reached Congress, with all parties seeking resolution as to what constitutes an ecologically and publicly acceptable management approach. Determining the correct management approach and communicating that approach to the general public is the crux of the problem. Emerging concepts and principles of forest ecosystem management may provide a mechanism to seek resolution of these management problems related to giant sequoia. The Memorandum of Understanding between the members of the recently formed Giant Sequoia Ecology Cooperative provided the impetus for the development of …

Comparison Of Sampling Methods Used To Estimate Spider (Araneae) Species Abundance And Composition In Grape Vineyards, Michael J. Costello, Kent M. Daane

Horticulture and Crop Science

The effectiveness of 3 methods for sampling spiders in grape vineyards was tested. The sampling methods were as follows: (1) a drop-cloth method in which spiders were dislodged from a 5.1-m2 area of grapevine onto a drop cloth, (2) a funnel method in which spiders were dislodged into a 0.74-m2 funnel, and (3) a D-vac method in which 50 sections of grapevine (30-cm sections, total area of 5.4 m2) were suctioned with a gasoline-powered vacuum. Data from all sampling methods were adjusted for area sampled and compared with an absolute control, in which foliage from an entire vine was removed …

Using Impedance For Mechanical Conditioning Of Tomato Transplants To Control Excessive Stem Elongation, Lauren C. Garner, Thomas Björkman

Horticulture and Crop Science

Mechanical stimulation is known to control excessive stem elongation in highdensity tomato (Lycopersicon esculentum Mill.) transplants. Mechanical stimulation using physical impedance provided height control equivalent to that obtained using brushing. Low-cost materials can be used to apply the impedance. Mylar film in a plastic frame was equivalent to expensive acrylic sheets in its effect on plant height (40 mm shorter than nontreated, a 40% reduction in the elongation rate during the treatment period), stem diameter (18% thicker), and biomass (14% lighter) when they applied a pressure of 66 N·m-2• Stem elongation was not reduced ifless pressure was applied (25 or50 …

Brushing Pansy (Viola Tricolor L.) Transplants: A Flexible, Effective Method For Controlling Plant Size, Lauren C. Garner, F. A. Langton

Horticulture and Crop Science

Though brushing is an effective method for controlling excessive elongation in many species, its adoption by the commercial plug transplant industry will depend on the ease and flexibility of its application. Brushing was applied to pansy (Viola tricolor L.) seedlings growing at a density of 1500 plants m^-2 by daily stroking with 20/20 gauge netting. In dose response experiments, final petiole length appeared to approach a lower asymptote as number of brush strokes increased, and the number of strokes required to give near full reduction in length increased under environmental conditions favouring extension growth. Ten or 20 daily …

Behavior Of Female Eretmocerus Sp. Nr. Californicus Howard (Aphelinidae: Hymenoptera) Attacking Bemisa Argentifolii Bellows And Perring (Aleyrodidae: Homoptera) On Two Native Californian Weeds, David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring

Horticulture and Crop Science

Searching and ovipositional behaviors by female Eretmocems sp. nr. californicus Howard on Bemisia argentifolii Bellows and Perring infesting velvetleaf, Abutilon theophrasti Medic. (Malavaceae), and telegraph weed, Heterotheca grandiflora Nutt. (Asteraceae), were quantified. Adult female behaviors were described and quantified for E. sp. nr. californicus to establish a behavioral time budget analysis. Females departed from leaves of A. theophrasti in 83.3% of the trials, and of those that remained and searched for hosts, walking speeds averaged 0.29 mm/s. Females departed from the leaves of H. grandiflora in 44.4% of the trials, and those remaining readily searched for whitefly hosts with walking …

Palmer Lter: Stable Interannual Successional Patterns Of Phytoplankton Communities In The Coastal Waters Off Palmer Station, Antarctica, Mark A. Moline, Barbara B. Prezelin, Oscar Schofield

Biological Sciences

No abstract provided.

Review Of A Manual Of California Vegetation By J. Sawyer & T. Keeler-Wolf, David J. Keil

Biological Sciences

No abstract provided.

Shortfin Mako, Isurus Oxyrinchus, Impaled By Blue Marlin, Makaira Nigricans (Teleostei: Istiophoridae), Harry L. Fierstine, Gregor M. Cailliet, Julie A. Neer

Biological Sciences

No abstract provided.

An Atlantic Blue Marlin, Makaira Nigricans, Impaled By Two Species Of Billfishes (Teleostei:Istiophoridae), Harry L. Fierstine

Biological Sciences

Billfishes (Istiophoridae and Xiphiidae) are notorious for driving their rostra into animate and inanimate objects, a behavior usually resulting in transverse fracture of the bill and leaving the distal segment embedded (Gudger, 1940; Frazier et aI., 1994). Some billfishes recover from this loss because there are records ofapparently healthy fish with missing rostra (Frazier et aI., 1994). Generally only one rostral fragment is found in each object, but multiple stabbings have been reported. For example, fragments of three swordfish bills were discovered in a whale during flensing (Jonsgard, 1962), several "marlin" spears were found impaled in bales of rubber that …

Instar Susceptibility Of The Monarch Butterfly (Danaus Plexippus) To The Neogregarine Parasite, Ophryocystis Elektroscirrha, Kingston L. H. Leong, Michael A. Yoshimura, H. K. Kaya, H. Williams

Biological Sciences

The susceptibility of the monarch butterfly (Danaus plexippus) larvae to the neogregarine parasite, Ophryocystis elektroscirrha, was tested in the laboratory. Spore loads recovered from infected monarch butterflies were directly related to the inoculum level, larval stage of the host, and spore age. There was a linear relationship between spores ingested by first instar larvae and spore concentration. Larvae feeding on leaves treated with 0, 50, 500, 5000, or 50,000 spores averaged 0, 0, 193, 457, or 1,255 spores, respectively, on the abdomens of the adult butterflies. When first, third, and fifth instar larvae were given 14.5 spores/mg …

Molecular Engineering Of Side-Chain Liquid Crystalline Polymers By Living Polymerizations, Coleen Pugh, Alan L. Kiste

Chemistry and Biochemistry

“Living” anionic, cationic, metalloporphyrin and ring-opening metathesis polymerizations have been used to prepare well-defined side-chain liquid crystalline homopolymers, block and graft copolymers and statistical copolymers. This paper analyzes their successes and failures by reviewing the mechanistic aspects and experimental conditions of each type of polymerization, and identifies other classes of mesogenic monomers that could be polymerized in a controlled manner in the future. The emerging structure/property relationships are then identified using well-defined SCLCPs in which only one structural feature is varied while all others remain constant.

The thermal transitions of liquid crystalline polymethacrylates, polynorbomenes and poly(viny1 ether)s reach their limiting …

Long-Term Monitoring And Analyses Of Physical Factors Regulating Variability In Coastal Antarctic Phytoplankton Biomass, In Situ Productivity And Taxonomic Composition Over Subseasonal, Seasonal And Interannual Time Scales, Mark A. Moline, Barbara B. Prezelin

Biological Sciences

A 3 yr high-resolution temporal data base related to phytoplankton dynamics was collected during the austral spring/summer periods of 1991 to 1994 in shelf waters adjacent to Palmer Station, Antarctica. Here, the data base is used (1) to quantify the variability in phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales; (2) to elucidate environmental mechanisms controlling these temporal patterns; and (3) to ascertain which phytoplankton markers are most suitable for detecting longer-term (i.e. decadal) trends in phytoplankton dynamics in coastal waters of the Southern Ocean. The Long-Term Ecological Research (LTER) coastal study sites …

Micronutrients And The Risk Of Colorectal Adenomas, Marilyn Tseng, Sharon C. Murray, Lawrence L. Kupper, Robert S. Sandler

Kinesiology and Public Health

Recent studies suggest that micronutrients, especially folate, calcium, iron, and antioxidant vitamins, affect the risk of colorectal neoplasia. The objective of this case-control study was to examine the association between these micronutrients and the risk of colorectal adenomas. The study was based on 236 cases with adenomatous polyps or cancer and 409 controls, all colonoscopy patients at University of North Carolina Hospitals between July 1988 and March 1991. After colonoscopy, subjects were interviewed using a semi-quantitative food frequency questionnaire, and average daily nutrient intakes were calculated. Sex-specific odds ratios relative to the lowest quartile of intake for each micronutrient were …

High-Resolution Time-Series Data For 1991/1992 Primary Production And Related Parameters At A Palmer Lter Coastal Site: Implications For Modeling Carbon Fixation In The Southern Ocean, Mark A. Moline, Barbara B. Prezelin

Biological Sciences

Our goal was to provide a high-resolution temporal data base for modeling primary production in shelf waters adjacent to Palmer Station, Antarctica. Here, the resulting 1991/1992 data base is used to: (1) determine in situ productivity over a range of seasonal to subseasonal time scales; (2) identify time scales of significant variability in marine productivity during the peak growing season; (3) identify environmental, experimental and analytical factors that can significantly impact the accuracy of daily, weekly and seasonal productivity estimates; and (4) integrate our findings with previous studies of Antarctic coastal primary pro- duction. Data were gathered every 2–3 days …

Genetic And Social Control Of Male Maturation In Phallichthys Quadripunctatus (Pisces: Poeciliidae), Gita R. Kolluru, David N. Reznick

Biological Sciences

Age and size at maturity can have significant fitness consequences. Selection often favors early-maturing individuals because of their higher survival to maturity and greater relative contribution to population growth rate, but it may also favor delayed maturation if fitness increases with age or size at maturity. Males of several poeciliid fishes exhibit variation in age and size at maturity primarily controlled by a sex-linked gene called the P-locus. Wild-caught Phallichthys quadripunctatus males show a bimodal size distribution, which is often associated with a P-locus polymorphism in other poeciliids. We conducted two experiments to evaluate the inheritance of male age and …

Azorhizobium Caulinodans Uses Both Cytochrome Bd (Quinol) And Cytochrome Cbb3 (Cytochrome C) Terminal Oxidases For Symbiotic N2 Fixation, Alexandre Kaminski, Christopher L. Kitts, Zachary Zimmerman, Robert A. Ludwig

Biological Sciences

Azorhizobium caulinodans employs both cytochrome bd (cytbd; quinol oxidase) and cytcbb3 (cytc oxidase) as terminal oxidases in environments with very low O2 concentrations. To investigate physiological roles of these two terminal oxidases both in microaerobic culture and in symbiosis, knockout mutants were constructed. As evidenced by visible absorbance spectra taken from mutant bacteria carrying perfect gene replacements, both the cytbd- and cytcbb3- mutations were null alleles. In aerobic culture under 2% O2 atmosphere, Azorhizobium cytbd- and cytcbb3- single mutants both fixed N2 at 70 to 90% of wild-type rates; in root nodule symbiosis, both single mutants fixed N2 at 50% …

High-Power Broadly Tunable Picosecond Ir Laser System For Use In Nonlinear Spectroscopic Applications, D. E. Gragson, B. M. Mccarty, G. L. Richmond, D. S. Alavi

Chemistry and Biochemistry

We developed a high-power tunable picosecond IR laser system suitable for nonlinear spectroscopic investigations. We employ a Ti:sapphire regenerative amplifier that produces 1.9-ps, 17-cm⁻¹, 800-nm pulses at 1 kHz as a pump source. White-light generation in ethylene glycol and optical parametric amplification in potassium titanyl phosphate are used to produce the IR pulses. The tuning range extends from 2.4 to 3.8 μm in the idler and 1.0 to 1.2 μm in the signal. A total efficiency (signal plus idler) as high as 20% was achieved. The spatial, spectral, and temporal characteristics of the IR beam are presented along …

Mechanical Conditioning For Controlling Excessive Elongation In Tomato Transplants: Sensitivity To Dose, Frequency, And Timing Of Brushing, Lauren C. Garner, Thomas Björkman

Horticulture and Crop Science

During production of plug transplants, the high plant density results in rapid stem elongation as plants compete for light. The resulting tall, weak-stemmed plants are difficult to transplant and are easily damaged. One technique that can prevent excessive elongation is mechanical stimulation by brushing. Wide adoption of brushing is limited by a lack of information on how plants respond to variations in applying the technique. Our investigation examined how tomato (Lycopersicon esculentum cv. Oh8245) seedling growth responded to varying doses of mechanical stimulation, varying intervals between brush strokes during stimulation, time of day that stimulation was applied, and growth stage …

Expression Of A Bovine Κ-Cn Cdna In The Mammary Gland Of Transgenic Mice Utilizing A Genomic Milk Protein Gene As An Expression Cassette, Alfonso Gutiérrez, Harry M. Meade, Paul Ditullio, Daniel Pollock, Merry Harvey, Rafael Jiménez-Flores, Gary B. Anderson, James D. Murray, Juan F. Medrano

Dairy Science

Transgenic mice were produced by microinjection of a DNA construct composed of the bovine κ-casein (κ-CN) cDNA under the control of the goat β-CN 5' promoter elements and 3' flanking regions into pronuclear-stage embryos. The gene construct targeted the expression of bovine κ-CN RNA to the mammary gland and secretion of bovine κ-CN in the milk. In the three lines studied (BC-7, BC-31 and BC-67) the transgene was stably integrated and propagated as a Mendelian locus. Expression of the bovine protein in lactating mice from the three transgenic lines was demonstrated by northern and western blots. In ten different tissues …

Issues Concerning The Eradication Or Establishment And Biological Control Of The Mediterranean Fruit Fly, Ceratitis Capitata(Wiedemann) (Diptera: Tephritidae), In California, David H. Headrick, Richard D. Goeden

Horticulture and Crop Science

Classical biological control is suggested as a tool worth developing now for possible future use in the integrated pest management of the Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), in California. Three factors that impact broadly on developing and implementing such a biological control program are: (1) the question of Medfly establishment, (2) quarantine considerations, and (3) agricultural and urban concerns. Each of these factors and their combined effects must be considered when discussing biological control of Medfly in California as shaped by historical perspectives on Medfly invasions, methods of Medfly eradication, and past biological control efforts against Medfly. We …

Two Erroneous, Commonly Cited Examples Of "Swordfish" Piercing Wooden Ships, Harry L. Fierstine, Oliver Crimmen

Biological Sciences

No abstract provided.

Critical Pressures In Multicomponent Lipid Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Epifluorescence microscopy has been used previously to study coexisting liquid phases in lipid monolayers of dihydrocholesterol and dimyristoylphosphatidylcholine at the air/water interface. This binary mixture has a critical point at room temperature (22°C), a monolayer pressure of approx. 10 mN/m, and a composition in the vicinity of 20-30 mol% dihydrocholesterol. It is reported here that this critical pressure can be lowered, raised, or maintained constant by systematically replacing molecules of this phosphatidylcholine with molecules of a phosphatidylethanolamine, or an unsaturated phosphatidylcholine, or mixtures of the two, while maintaining the dihydrocholesterol concentration at 20 mol%. Thus, even complex mixtures of lipids …

Efficacy Of Herbicide Application Methods Used To Control Tanoak (Lithocarpus Densiflorus) In An Uneven-Aged Coast Redwood Management Context, Douglas D. Piirto, Brenda Smith, Eric K. Huff, Scott T. Robinson

Natural Resources Management and Environmental Sciences

Three methods of tanoak (Lithocarpus densiflorus [Hook. & Arn.] Rehd.) control involving the application of the amine or ester form of triclopyr were evaluated in this coast redwood uneven-aged forest management study of herbicides. A cut-stump application with the amine form of triclopyr (Garlon 3A), frill cut with the amine form of triclopyr, basal-bark (outer surface) with the ester form of triclopyr (Garlon 4), and an untreated control were replicated three times. The tanoak control results in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and/ or coast redwood (Sequoia sempervirens [D. Don] Endl.) predominated stands obtained in earlier studies …

Host-Plant Effects On The Behavior Of Eretmocerus Sp. Nr. Californicus Females Raised From Melon, David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring

Horticulture and Crop Science

The behaviors of female Eretmocerus sp. nr. californiens raised from Bemisia argentifolii Bellows & Perring on melon, Cucumis melo L., were analysed on four different host plant species (cotton, melon, sweet potato and Abutilon theophrasti Medic). Comparison with previously published results of similarly treated females reared from sweet potato plants showed performance related differences leading to oviposition. In the present study, the generalized behavioral pathway (walking, host- encounter, antennation, probing and oviposition) did not vary among host plant species for melon- reared parasitoid females. Host assessment by antennation leading to host acceptance for probing varied from 10.5- 12.3 sec among …

Use Of Rostral Characters For Identifying Adult Billfishes (Teleostei: Perciformes: Istiophoridae And Xiphiidae), Harry L. Fierstine, Nicole L. Voigt

Biological Sciences

Seven species of the family Istiophoridae and Xiphias gladiu6 were identified using only features of their rostrum. In the Istiophoridae, two rostral regions were emphasized, one-fourth and one·half the distance between the distal tip and the orbital margin of the lateral ethmoid bone. Characters studied in each region were the depth and width of rostrum and height, width, and position of nutrient canals (as seen in cross-section). Characters studied without reference to region were the distribution of denticles on both dorsal and ventral surfaces of the bilI and position of the prenasal bone. In the Xiphiidae, the only characters studied …

Behaviors Of Female Eretmocerus Sp. Nr. Californicus (Hymenoptera: Aphelinidae) Attacking Bemisia Argentifolii (Homoptera: Aleyrodidae) On Cotton, Gossypium Hirsutum, (Malavaceae) And Melon, Cucumis Melo (Cucurbitaceae), David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring

Horticulture and Crop Science

Behaviors of Eretmocerus sp. nr. californicus females attacking Bemisia argentifolii Bellows & Perring infesting cotton, Gossypium hirsutum L., and melon, Cucumis melo L., were quantified. Adult female behaviors were described and quantified for Eret. sp. nr. californicus to establish a behavioral time budget analysis. Females readily searched for host whitefly nymphs on cotton leaves with walking speeds averaging 0.5 mm/s. Females remained infrequently on melon leaves; those that did remain and search for hosts averaged walking speeds of 0.33 mm/s. The duration of host assessment by antennation was related to subsequent behaviors. Rejecting a host was a shorter process than …

Trade-Offs In Parasitology, Evolution And Behavior, Marlene Zuk, M. J. Bryant, Gita R. Kolluru, V. Mirmovitch

Biological Sciences

No abstract provided.

Description Of The Male Ceranisus Americensis (Girault) (Hymenoptera: Eulophidae), Serguei V. Triapitsyn, David H. Headrick

Horticulture and Crop Science

No abstract provided.