Estimation of methanotroph abundance in a freshwater lake sediment

The numbers of methane-oxidizing bacteria (methanotrophs) in the sediments of Lake Washington were estimated using three culture-independent methods. Quantitative slot-blot hybridizations were performed with type I and type II methanotroph-specific probes. These data were compared to data from quantitative hybridizations using a pmoA-specific probe and a eubacterial probe. From the combined hybridization data, the methanotroph population in Lake Washington was estimated to be 3.6 x 10(8)-7.4 x 10(8) cells/g dry weight. Methanotroph community structure and number were also investigated using polar lipid fatty acid (PLFA) analysis. Analysis of biomarker PLFAs characteristic of both type I (16:1 omega 8) and type II (18:1 omega 8) methanotrophs was used to estimate the abundance of these bacteria in Lake Washington sediments. From the PLFA data, the methanotroph population in Lake Washington was estimated to be 7.1 x 10(8)-9.4 x 10(9) cells/g dry weight. As a third method of quantitation, we calculated the methanotroph population using the total methane oxidation rate for whole cells in Lake Washington sediment to be 1.3 x 10(8)-1.2 x 10(9) cells/g dry weight. The three independent estimates of the number of methanotrophs in Lake Washington sediment agree within a two- to fourfold range. These data suggest that the three techniques used in this study detect the functionally significant population of methanotrophs in Lake Washington. Furthermore, these techniques will be useful for obtaining estimates of methanotroph abundance in additional environments.     

Serological survey for heartworm (Dirofilaria immitis) in dogs in Washington

The serologic prevalence of Dirofilaria immitis infection in 601 dogs in Washington was investigated in 1989-1990. Blood samples for serum were obtained from dogs approximately 2 yr of age or older in humane society shelters (n = 392) or veterinary clinics (n = 209). Serum samples were tested for heartworm infection using an enzyme-linked immunosorbent assay antigen test. Three (0.5%) dogs were positive for D. immitis infection, all of which were born and lived several years in states other than Washington. Heartworms have not been detected during the last 9 yr in the 1,203 dogs examined at the Washington Animal Disease Diagnostic Laboratory, Pullman, Washington. Consequently, the likelihood of indigenous heartworm infections in dogs in Washington remains low at this time.     

Seasonal Migration of Meloidogyne chitwoodi and its Role in Potato Production

Seasonal vertical migration of Meloidogyne chitwoodi through soil and its impact on potato production in Washington and Oregon was studied. Nematode eggs and second-stage juveniles (J2) were placed at various depths (0-180 cm) in tubes filled with soil and buried vertically or in holes dug in potato fields. Tubes were removed at intervals over a 12-month period and soil was bioassayed on tomato roots. Upward migration began in the spring after water had percolated through the tubes. Nematodes were detected in the top 5 cm of tubes within 1-2 months of burial, depending on depth of placement. Potatoes were grown in field plots for 4 or 5 months before the tubers were evaluated for infection. One hundred eggs and J2 per gram soil placed at 60 and 90 cm caused significant tuber damage at the Washington and Oregon sites, respectively. At the Washington site, inoculum placed at 90, 120, and 150 cm caused potato root infection without serious impact on tuber quality, but inoculum diluted 2-8 times and placed at 90 cm did not cause root or tuber infection. Nematode migration was dependent on soil texture; 9 days after placement at the bottoms of tubes, J2 had moved up 55 cm in sandy loam soil (Oregon) but only 15 cm in silt loam (Washington). Thus, the importance of M. chitwoodi which occur deep in a soil profile may depend on soil texture, population density, and length of the growing season.     

How will knowing genome sequences affect the life of the average cell biologist?

A report on work presented at the 39th Annual Meeting of the American Society for Cell Bilogy, Washington DC, December 11-15, 1999     

Colonization of America by Drosophila subobscura: spatial and temporal lethal-gene allelism

About twenty years ago Drosophila subobscura, a western Palearctic species, colonized both North and South America. Lethal genes in the O chromosome has been subject to much research. Lethal gene allelisms between American populations far away have been studied. These allelisms were not negligible, but all cases were due to the lethal gene completely associated to the O5 chromosomal inversion. Here we analyze the lethal genes in a new American population of D. subobscura (Centralia, Washington), located fairly close to a previously studied population (Bellingham, Washington) and separated in space and time with other American populations (Gilroy I and II in California and Santiago de Chile). The frequencies of lethal and semilethal genes of Centralia were 16.9+/-4.6 and 6.2+/-3.0, respectively. The intrapopulational allelism of Centralia was 0.122+/-0.036. Interpopulational allelisms were studied using the lethal genes from the populations separated in space and time from Centralia. The interpopulational allelisms between Centralia and Gilroy I (California) and between Centralia and Bellingham (Washington) were higher than the intrapopulational allelism (0.155+/-0.032 and 0.153+/-0.024, respectively). In all these cases allelism was due to a complete association between a lethal gene and the O5 chromosomal inversion. Accordingly, no other lethal genes are shared in these populations.     

Cell motility and the formation of lamellipodia

A report on work presented at the 39th Annual Meeting of the American Society for Cell Bilogy, Washington DC, December 11-15, 1999     

Recent advances in <Emphasis Type="Italic">Drosophila</Emphasis> genomics

A report on the 45th annual Drosophila Research Conference, Washington DC, USA, 23-28 March 2004.     

Determining the cellular function of myosin VI

A report on work presented at the 39th Annual Meeting of the American Society for Cell Biology, Washington DC, December 11-15, 1999     

Is circadian type associated with sleep duration in twins?

Sleep and Biological Rhythms - We used the community-based University of Washington Twin Registry to investigate the genetic association between circadian type and sleep duration. Habitual sleep...     

From proteases to proteomics

This personal and professional autobiography covers the 50-yr period of 1950-2000 and includes the following topics: History of the University of Washington School of Medicine and its Department of Biochemistry (Mount Rainier and the University of Washington, recruiting faculty, biology, research programs); scientific editing (publication, Biochemistry, Protein Science, electronic publication); Europe revisited (Heidelberg, approaching retirement, the German Research Center, reunion in Vienna); and 50 yr of research on proteolytic enzymes (trypsin, carboxypeptidases, mast cell proteases, future developments).     

Cell-cycle regulation

A report on the 'cell-cycle regulation' minisymposium at the 41st Annual Meeting of the American Society for Cell Biology, Washington DC, USA, 8-12 December 2001.     

A hitchhiker's guide to cell biology: exploitation of host-cell functions by intracellular pathogens

A report on the 'Pathogen-host cell interactions' minisymposium at the 41st Annual Meeting of the American Society for Cell Biology, Washington DC, USA, 8-12 December 2001.     

Regulated secretion

A report from the minisymposium on regulated secretion at the 39th Annual Meeting of the American Society for Cell Bilogy, Washington DC, December 11-15, 1999     

Chemical approaches to understanding biological mechanisms

A report on work with small-molecule inhibitors of cellular processes presented at the 39th Annual Meeting of the American Society for Cell Bilogy, Washington DC, December 11-15, 1999     

Identifying transcribed sequences,and beyond

A report on the 12th International Workshop 'Beyond the Identification of Transcribed Sequences (BITS): Functional, Expression and Evolutionary Analysis', Washington DC, USA, 25-28 October 2002.     

Trading Identities: The Souvenir in Native North American Art from the Northeast, 1700–1900

Trading Identities: The Souvenir in Native North American Art from the Northeast, 1700-1900. Ruth B. Phillips. Seattle: University of Washington Press, 1998. 334 pp.     

Pesticide formulations: Innovations and developments

Book Review

Pesticide formulations: Innovations and developmentsB. Cross and H.B. Scher (Eds.), ACS Symposium Series 371. Washington DC: American Chemical Society, 1988. xi + 288 pages. £54.00. ISBN 0-8412-1483-2     

Dynamics of the nucleus

A report of work on the structure and function of the nuclear envelope and nuclear pores, presented at the 39th annual meeting of the American Society for Cell Biology, Washington DC, December 11-15, 1999.     

Use of genomic data in risk assessment

A report on the Contemporary Concepts in Toxicology workshop 'Use of Genomic Data in Risk Assessment: State of the Art 2001' held by the Society of Toxicology, Washington DC, USA, 7-8 November 2001.     

Immunogold localization of chymotrypsin inhibitor-2, a lysine-rich protein,in developing barley endosperm

Chymotrypsin inhibitor-2, a lysine-rich protein in the barley endosperm, has been localized at the ultrastructural level by immunocytochemistry in developing barley endosperm cells 14 days post anthesis. The protein is deposited in the protein bodies. Two morphologically distinct types of protein bodies, small spherical and large irregularly shaped, are present. Golgi-apparatus-derived vesicles whose content is labelled by chymotrypsin inhibitor-2 antibody-gold particles are observed at the Golgi complex and around the vacuoles. These observations indicate that the transport of the protein to the site of deposition is mediated by the Golgi apparatus.Abbreviations CI chymotrypsin inhibitor - DPA days post anthesis - ER endoplasmic reticulum The authors wish to thank Dr. V.R. Franceschi (Department of Botany, Washington State University, Pullman, USA) for many helpful discussions and advice during the work, and the staff at the Electron Microscope Center at Washington State University for technical assistance.