DNA damage and biliary PAH metabolites in flatfish from Southern California bays and harbors, and the Channel Islands

Southern California bays and harbors have been shown to contain high concentrations of a variety of contaminants, including polycyclic aromatic hydrocarbons (PAHs), metals, and pesticides. Conventional monitoring tools do not assess exposure to PAHs in fish, or sublethal effects, which can be more sensitive indicators of stress than traditional methods. This study was conducted to evaluate DNA damage (a sublethal effect) and PAH exposure in flatfish from southern California bays and harbors, and the Channel Islands. California halibut (Paralichthys californicus) were collected from eight bays and harbors (Ventura Harbor, Channel Islands Harbor, Marina del Rey, King Harbor, Alamitos Bay, Long Beach Harbor, Newport Bay, San Diego Bay), and a reference site off Camp Pendleton. Pacific sanddab (Citharichthys sordidus) were collected near four of the Channel Islands (San Miguel Island, Santa Cruz Island, Anacapa Island, Santa Barbara Island). Metabolites of high molecular weight PAHs in fish bile were characterized using a semi-quantitative technique that measures fluorescent aromatic compounds (FACs) in fish bile. DNA damage in fish blood cells was assessed by measuring the amount of single-strand breaks in stained DNA using the Comet assay. The concentration of FACs in fish from all bays and harbors was elevated, with average concentrations ranging from three to ten times greater than FACs in reference fish. FAC levels were elevated in Pacific sanddabs from a Channel Islands station located between Santa Cruz Island and Anacapa Island. DNA damage varied by a factor of five among California halibut from bays and harbors, with significant damage occurring in fish from Alamitos Bay. There was a significant association between FAC concentrations and DNA damage in California halibut at Marina del Rey and Ventura Harbor, but not at other locations, presumably due to contaminants other than PAHs.     

Myasthenia Gravis

Taken from the weekly Pediatric Grand Rounds held at the University Hospital of San Diego County, University of California, San Diego, School of Medicine, June 20, 1972     

The Transformation of Rural Mexico: Reforming the Ejido Sector.

The Transformation of Rural Mexico: Reforming the Ejido Sector. Wayne A. Cornelius and David Myhre. eds. San Diego, CA: Center for US-Mexican Studies, University of California, San Diego, 1998. 438 pp.     

Range and Frequency of Africanized Honey Bees in California (USA)

Africanized honey bees entered California in 1994 but few accounts of their northward expansion or their frequency relative to European honey bees have been published. We used mitochondrial markers and morphometric analyses to determine the prevalence of Africanized honeybees in San Diego County and their current northward progress in California west of the Sierra Nevada crest. The northernmost African mitotypes detected were approximately 40 km south of Sacramento in California’s central valley. In San Diego County, 65% of foraging honey bee workers carry African mitochondria and the estimated percentage of Africanized workers using morphological measurements is similar (61%). There was no correlation between mitotype and morphology in San Diego County suggesting Africanized bees result from bidirectional hybridization. Seventy percent of feral hives, but only 13% of managed hives, sampled in San Diego County carried the African mitotype indicating that a large fraction of foraging workers in both urban and rural San Diego County are feral. We also found a single nucleotide polymorphism at the DNA barcode locus COI that distinguishes European and African mitotypes. The utility of this marker was confirmed using 401 georeferenced honey bee sequences from the worldwide Barcode of Life Database. Future censuses can determine whether the current range of the Africanized form is stable, patterns of introgression at nuclear loci, and the environmental factors that may limit the northern range of the Africanized honey bee.     

A festival of cell-cycle controls.

The second biennial Salk Cell Cycle meeting convened on 22 June 2001 in San Diego, California. Organized by Tony Hunter and Susan Forsburg of the Salk Institute, the five-day conference was highlighted by enlightening science and plenty of San Diego sunshine. Presentations covered a broad range of contemporary cell-cycle topics, ranging from regulation of DNA replication and mitosis to DNA damage recognition and checkpoint control.     

Third International Conference on Bispecific Antibodies and Targeted Cellular Cytotoxicity,Rosa Marina Hotel,Ostuni Brindisi,Italy, 13–17 June 1992

Third International Conference on Bispecific Antibodies and Targeted Cellular Cytotoxicity, Rosa Marina Hotel, Ostuni Brindisi, Italy, 13–17 June 1992     

RANGE CHARACTERISTICS OF PACIFIC COAST BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN THE SOUTHERN CALIFORNIA BIGHT

Boat-based photoidentification surveys of bottlenose dolphins (Tursiops truncatus) were conducted from 1982 to 1989 in three discrete coastal study areas within the Southern California Bight: (1) Santa Barbara, California; (2) Orange County, California; (3) Ensenada, Baja California, Mexico. A total of 207 recognizable dolphins were identified in these three “secondary” study areas. These individuals were compared to 404 dolphins identified from 1981 to 1989 in our “primary” study area, San Diego, California, to examine the coastal movement patterns of bottlenose dolphins within the Southern California Bight. A high proportion of dolphins photographed in Santa Barbara (88%), Orange County (92%), and Ensenada (88%) were also photographed in San Diego. Fifty-eight percent (n= 120) of these 207 dolphins exhibited back-and-forth movements between study areas, with no evidence of site fidelity to any particular region. Minimum range estimates were 50 and 470 km. Minimum travel-speed estimates were 11-47 km/d, and all dolphin schools sighted during the study were within 1 km of the shore. These data suggest that bottlenose dolphins within the Southern California Bight are highly mobile within a relatively narrow coastal zone. Home-range dimensions and movement patterns for many vettebrate species are influenced, in part, by variation in food resources. The unique range characteristics documented during this study may reflect the highly dynamic nature of this coastal ecosystem and the associated patchy distribution of food resources available to these bottlenose dolphins.     

A new Senecio (Compositae) from California

Senecio ganderi is described as new from San Diego County, California. It is referable to theAurei species-group and is distinguished by its orange-yellow corollas, cordate to subcordate basal leaves, and its restriction to chaparral and recently burned areas.     

Exotic plant invasions in an endemic‐rich habitat: The spread of an introduced Australian grass,Agrostis avenacea J. F. Gmel., in California vernal pools

Abstract The present abundance and historical spread of an exotic grass, Agrostis avenacea, is documented for California, USA, and for the vernal pools of San Diego County in particular. Agrostis avenacea is native to Australia where it is a common grass of ephemeral and fluctuating wetlands. California vernal pools, by reason of their extreme variability and high endemism, have been thought to be relatively resistant to invasion. The recent expansion of A. avenacea in San Diego County demonstrates, however, that the alleged resistance is probably a function of a relatively small pool of invaders and a low probability of targeted dispersal. Although A. avenacea is now abundant in pools with little current disturbance, human disturbance appears to have been a major factor that facilitated its initial establishment. This specific instance adds to the mounting evidence that there are probably few, if any, habitats immune to invasion.     

Morphologic evidence of poxvirus in "tattoo" lesions from captive bottlenosed dolphins.

Skin lesions known as "tattoos", were observed in several captive Atlantic bottlenosed dolphins (tursiops truncatus) maintained at the Naval Ocean Systems Center, San Diego, California. Biopsy of typical lesions and subsequent ultrastructural examination revealed intracytoplasmic particles with poxvirus morphology.     

Pre-mission invasion of Erodium cicutarium in California

Abstract. The California grassland is dominated by alien plant species. It is generally assumed that the invasion of aliens began with the initial introduction of livestock by Spanish missionaries in 1769. In this paper we present pollen evidence which indicates that Erodium cicutarium, a Mediterranean annual, was well established in the Santa Barbara region several years before the founding of the first California mission at San Diego in 1769. Historical evidence shows that it took the Spanish nearly a decade to develop a livestock base in California. Disturbance by livestock was therefore not a necessary prerequisite for invasion by alien plants. Historical and macrofossil evidence indicates that E. cicutarium invaded California from Baja California.     

A Concept of Educational Activity for Schoolchildren

About two years ago, on a cool Southern California day, Vasili Davydov addressed a group of social scientists at the University of California, San Diego. He began his talk with a paradox. He had come, he said, to tell us about educational activity. He promised to exhibit principles that promote educational activity, and applied programs deriving from those principles. Then he laughed. "But you'll never see educational activity in the school," he said, and laughed again.     

Spatially explicit and multi-sourced genetic information is critical for conservation of an endangered plant species,San Diego thornmint (<Emphasis Type="Italic">Acanthomintha ilicifolia</Emphasis>)

San Diego thornmint Acanthomintha ilicifolia (Gray) Gray (Lamiaceae) is a winter herb restricted to San Diego county in the United States and Baja California Norte in Mexico. Historic records document 80 occurrences of this species, with 55 extant occurrences in San Diego County currently known. We compared three measures of genetic variation to inform ongoing conservation efforts: putatively neutral genetic structure revealed from isozyme markers, apparent cytogenetic variation confirmed using flow cytometry, and potentially adaptive morphological variation quantified in a common-garden study. Together, these data indicated that this rare endemic is genetically complex, revealing significant differentiation of neutral and potentially adaptive genetic variation among populations, and possessing at least two cytotypes, sometimes even within the same population. While additional study is required to resolve the extent of potential local adaptation in this species, conservation plans should limit the movement of germplasm among occurrences and monitor populations in order to limit potential long-term impacts to population viability. Given that these findings challenge the canonical model of genetic structure in rare plants (low genetic variation and limited genetic structure), we recommend guidelines to apply genetic information to conservation strategies.     

What price medical malpractice insurance?

The Medical Review and Advisory Board has been established as a committee of the Commission on Professional Welfare of the California Medical Association to make studies and recommendations toward solution of the growing problems of professional liability insurance and malpractice actions in California. The members of the Board are: Joseph F. Sadusk, Jr., Oakland, Chairman; Wilbur Bailey, M.D., Los Angeles, vice-chairman; Howard W. Bosworth, M.D., Los Angeles; H. I. Burtness, M.D., Santa Barbara; Paul W. Frame, Jr., M.D., Sacramento; Verne G. Ghormley, M.D., Fresno; Carl M. Hadley, M.D., San Bernardino; Joseph J. O'Hara, M.D., San Diego; William F. Quinn, M.D., Los Angeles; Rees B. Rees, M.D., San Francisco; and Bernard Silber, M.D., Redwood City; Mr. Rollen Waterson, 564 Market Street, San Francisco 4, is executive secretary, and Mr. Howard Hassard is legal counsel.     

An interview with Dr. Paolo Sassone-Corsi on his highly cited paper published in Cell Cycle

Paolo Sassone-Corsi graduated in genetics at the University of Naples, Italy, and then conducted post-doctoral studies at the CNRS in Strasbourg, France, and at The Salk Institute, San Diego California. After being Directeur de Recherche at the CNRS in France from 1990 to 2006, he moved to the University of California, Irvine, where he is Distinguished Professor and Chair of the Department of Pharmacology. His research focuses on the mechanisms of gene expression, including chromatin remodeling, circadian rhythms and germ cells.     

Host-parasite interactions: an interview with Emily Troemel

Emily Troemel is a Professor at the University of California San Diego, where her lab uses Caenorhabditis elegans to study host–pathogen interactions and the shaping of the immune response. In this interview, Emily shared her thoughts on peer review and its role in training future scientists, and the possibility of a new form of immunity in epithelia.     

Q & A

Leslie Orgel is a Professor and Senior Fellow at the Salk Institute in La Jolla, California, and an Adjunct Professor at the University of California at San Diego. The first part of his career was devoted to the theoretical inorganic chemistry of transition metal ions. This led to the publication of a book on Ligand-Field Theory. Since 1964, he has concentrated on aqueous solution chemistry that might be relevant to the origin of life. He has authored or co-authored two books on the origin of life.     

A UNIQUE COLONIAL MARINE CENTRIC DIATOM,COENOBIODISCUS MURIFORMIS GEN. ET SP. NOV.1

A new colonial centric marine diatom, Coenobio-discus muriformis gen. et sp. nov. (family Coscinodiscaceae) has been found in San Diego Bay, San Diego, California. The colony is composed of a single layer of 200-530 cells linked girdle to girdle by a compartmentalized matrix. The colony has the shape of a slightly concavo-convex disk approximately 400 μ. in diameter. Each cell is about 10 μ, in diameter and the valves have many structural features in common with those of Thalassiosira. The organic matrix contains 6-11 partitions that radiate from each cell, forming a number of extracellular chambers. The organic matrix does not contain chitin or cellulose as a major constituent. Histochemical similarities are found with the capsular and tubular material of previously described diatoms. The colonies reproduce without passing through a unicellular vegetative stage.     

Poor reproductive success of Gray Vireos in a declining California population

Since the 1940s, populations of Gray Vireos (Vireo vicinior) in California have collapsed, presumably because of parasitism by Brown‐headed Cowbirds (Molothrus ater). In 2012 and 2013, we studied the vireo's nesting ecology to assess factors affecting two of California's largest remaining populations in the chaparral of San Diego County. Nest success was extremely low, with a model‐averaged probability of nest survival of only 0.08 (N = 95). More nest failures were due to predation (83%) than to cowbird parasitism (13%). Video‐recording at 30 nests revealed that California Scrub‐Jays (Aphelocoma californica) were the most common nest predator (67%). Of eight variables tested, height of shrubs surrounding the nest had the strongest negative influence on nest survival, but was more strongly correlated with cowbird parasitism than with jay predation. Despite frequent renesting, seasonal productivity was well below the level required to sustain a population, especially in northern San Diego County where we found no Gray Vireos at six of seven sites where they had been present from 1997 to 2001 and where cowbird parasitism was more frequent. The vireo's continuing range collapse contrasts with recent climate‐change models predicting a range expansion, highlighting the importance of demographic studies. Low nest success is likely contributing to population declines in California, and the additive effect of cowbird parasitism suppresses productivity. Conservation of Gray Vireos in California will likely require development of alternative approaches to cowbird and scrub‐jay control appropriate to sites widely scattered in rugged chaparral.     

Short communication. Statolith microstructure from hatchlings of the oceanic squid, Gonatus onyx (Cephalopoda, Gonatidae) from the Northeast Pacific

Statolith microstructure was studied in hatchlings of deepwater-spawned gonatid squid Gonatus onyx, caught between 1350 and 1420 m over a bottom depth of 2100 m in the San Clemente Basin off San Diego, California. It was found that the shape and size of the hatchling statolith were similar to those of the first-check statolith observed in paralarvae and small juveniles of G.onyx. The inner part of the bipartite postnuclear zone (= first-check statolith) is formed during late embryo-genesis, and the first check within the statolith microstructure must be considered as a starting point of increment counting for age estimation of Gonatus spp.