The use of ultrasonic imaging to evaluate the effect of protozoan grazing and movement on the topography of bacterial biofilms.

AIMS: This study evaluated the effect of protozoan movement and grazing on the topography of a dual-bacterial biofilm using both conventional light microscopy and a new ultrasonic technique. METHODS AND RESULTS: Coupons of dialysis membrane were incubated in Chalkley's medium for 3 days at 23 degrees C in the presence of bacteria (Pseudomonas aeruginosa and Klebsiella aerogenes) alone, or in co-culture with the flagellate Bodo designis, the ciliate Tetrahymena pyriformis or the amoeba Acanthamoeba castellanii. Amoebic presence resulted in a confluent biofilm similar to the bacteria-only biofilm while the flagellate and ciliate created more diverse biofilm topographies comprising bacterial microcolonies and cavities. CONCLUSIONS: The four distinct biofilm topographies were successfully discerned with ultrasonic imaging and the method yielded information similar to that obtained with conventional light microscopy. SIGNIFICANCE AND IMPACT OF THE STUDY: Ultrasonic imaging provides a potential way forward in the development of a portable, nondestructive technique for profiling the topography of biofilms in situ, which might aid in the future management of biofouling.

Emerging areas of research reported during the CDC National Conference on Pfiesteria: from biology to public health.

Since its identification in 1996, the marine dinoflagellate Pfiesteria piscicida Steidinger & Burkholder has been the focus of intense scientific inquiry in disciplines ranging from estuarine ecology to epidemiology and from molecular biology to public health. Despite these research efforts, the extent of human exposure and the degree of human illness directly associated with Pfiesteria is still in the process of being defined. Unfortunately, during this same time Pfiesteria has also stimulated media coverage that in some instances jumped ahead of the science to conclude that Pfiesteria presents a widespread threat to human health. Political and economic forces also came into play when the tourism and seafood industries were adversely impacted by rumors of toxin-laden water in estuaries along the east coast of the United States. Amid this climate of evolving science and public concern, Pfiesteria has emerged as a highly controversial public health issue. In October 2000 Centers for Disease Control and Prevention sponsored the National Conference on Pfiesteria: From Biology to Public Health to bring together Pfiesteria researchers from many disparate disciplines. The goal of this meeting was to describe the state of the science and identify directions for future research. In preparation for the conference an expert peer-review panel was commissioned to review the existing literature and identify research gaps; the summary of their review is published in this monograph. During the meeting primary Pfiesteria researchers presented previously unpublished results. The majority of those presentations are included as peer-reviewed articles in this monograph. The discussion portion of the conference focused upon researcher-identified research gaps. This article details the discussion segments of the conference and makes reference to the presentations as it describes emerging areas of Pfiesteria research.

Qualitative study of clinic staff members' experiences using an immunization registry.

OBJECTIVES: To examine individual clinic staff members' experiences with using an immunization registry and to compare staff members' perceptions of immunization registries across different provider sites. DESIGN: Cross-sectional survey using in-depth interviews and direct observation. SETTINGS: The pediatric department of an urban community health center and 2 urban hospital-based pediatric primary care clinics. PARTICIPANTS: Twenty-five subjects were recruited using maximum variation sampling at each site. The subjects included clerks, clinic assistants, licensed practical nurses, a nurse practitioner, and registered nurses. MAIN OUTCOME MEASURES: Clinic staff members' perceptions of an immunization registry and frequency of registry use. RESULTS: Differences were observed in subjects' perceptions of an immunization registry across provider sites. Although most subjects had positive attitudes toward the registry, they did not necessarily believe that the registry decreased their workload. The ability to access immunization registry data and actual use of the registry seem to be related to training of clinic personnel, location of the registry terminal, and helpfulness and availability of registry staff. CONCLUSION: Obtaining the opinions of immunization registry users is an important strategy to evaluate the usefulness of a registry in a site and target possible areas for improvement.

Effects of chronic kombucha ingestion on open-field behaviors, longevity, appetitive behaviors, and organs in c57-bl/6 mice: a pilot study.

Kombucha is a lightly fermented tea beverage popularly consumed as a self-prescribed folk-remedy for numerous ailments. Kombucha is claimed to enhance cognition, aid weight loss, and prolong life. This pilot study reports longevity, general health, and open-field exploratory behavioral outcomes from a 3-y longitudinal study of 64 C57-BL/6 mice (males and females), half of which chronically drank kombucha, and all of which experienced natural mortality. Compared by MANOVA to controls, mice that drank kombucha showed greater vertical exploration (P = 0.001) and a sex-interactive effect in novel object manipulation (P = 0.049). MANOVA of kombucha-drinking mice compared to controls detected differences in appetitive behaviors (food consumption, P < 0.001; beverage consumption, P = 0. 008), and gross body weight (P < 0.001). Appetitive behaviors changed with the addition of voluntary exercise on a running wheel, with differing patterns of change noted for males and females. Both male and female mice who drank kombucha lived longer than controls (P < 0.001), with the greatest variability among the male mice (sex interactive effect, P < 0.001). Comparable effects and mechanisms in humans remain uncertain, as do health safety issues, because serious health problems and fatalities have been reported and attributed to drinking kombucha.

Acoustic absorption due to proton transfer in solutions of proteins, peptides and amino acids at neutral pH.

Measurements of ultrasonic absorption in the frequency range 2 to 60 MHz have been made on solutions of the amino acid histidine, dipeptides glycyl tyrosine and histidyl tyrosine, and proteins lysozyme and bovine serum albumin. Measurements were carried out at 37 degrees C and covered the pH range 6.8 to 7.7. Mechanisms for the observed excess acoustic absorption involving bimolecular and intramolecular proton transfer are considered.

Chimeric rhinoviruses as tools for vaccine development and characterization of protein epitopes.

Chimeric human rhinoviruses (HRVs) have the potential to serve as vaccines against a wide variety of diseases. Such vaccines can be developed optimally by generating libraries of chimeric HRVs displaying immunogens from dangerous pathogens or tumor cells in many different conformations. Extremely large numbers of conformationally defined presentations of foreign epitopes can be produced efficiently by flanking transplanted epitopes with linkers, or adapters, of small segments of randomized amino acids. In addition, the individual residues of the immunogenic sequences can be encoded in proportion to their prevalence in databases, generating composite immunogens that function as mimotopes. The diversity of sequences and conformations improves the likelihood of generating immunologically valuable vaccine candidates. Chimeric viruses thus generated can be propagated and purified to select for viruses whose growth and physical stability are like those of wild-type HRV. Viruses containing a foreign epitope in antigenically relevant conformations can then be captured by immunoselection with neutralizing antibodies directed against the foreign pathogen. Using this approach, we have been able to generate HRV chimeras that present V3 loop sequences of the human immunodeficiency virus type 1 (HIV-1) in immunologically relevant conformations. Antisera directed against such chimeras can neutralize multiple strains of HIV-1 in cell culture, suggesting that the HRV14:HIV-1 chimeras may be presenting their V3 loop sequences in manners that mimic those of multiple strains of HIV. Immunologically interesting chimeras can be examined using X-ray crystallography to yield detailed information about the structures of chimeras with immunogenic epitopes. This information may lead to a greater understanding of key functional and structural elements of immunogenicity. The chimeric HRV system allows one to present virtually any protein epitope or mimitope thereof, identify viruses with immunological characteristics that mimic those of the foreign pathogen, and examine the structures of these immunogenic sequences at the atomic level.