Evaluation of the Efficacy of Methyl Bromide in the Decontamination of Building and Interior Materials Contaminated with Bacillus anthracis Spores

The primary goal of this study was to determine the conditions required for the effective inactivation of Bacillus anthracis spores on materials by using methyl bromide (MeBr) gas. Another objective was to obtain comparative decontamination efficacy data with three avirulent microorganisms to assess their potential for use as surrogates for B. anthracis Ames. Decontamination tests were conducted with spores of B. anthracis Ames and Geobacillus stearothermophilus, B. anthracis NNR1Δ1, and B. anthracis Sterne inoculated onto six different materials. Experimental variables included temperature, relative humidity (RH), MeBr concentration, and contact time. MeBr was found to be an effective decontaminant under a number of conditions. This study highlights the important role that RH has when fumigation is performed with MeBr. There were no tests in which a ≥6-log₁₀ reduction (LR) of B. anthracis Ames was achieved on all materials when fumigation was done at 45% RH. At 75% RH, an increase in the temperature, the MeBr concentration, or contact time generally improved the efficacy of fumigation with MeBr. This study provides new information for the effective use of MeBr at temperatures and RH levels lower than those that have been recommended previously. The study also provides data to assist with the selection of an avirulent surrogate for B. anthracis Ames spores when additional tests with MeBr are conducted.     

Simple Procedure for Rapid Identification of Vibrio cholerae from the Aquatic Environment

Biochemical tests commonly used to screen for Vibrio cholerae in environmental samples were evaluated, and we found that a combination of alkaline peptone enrichment followed by streaking on thiosulfate citrate bile salts sucrose agar and testing for arginine dihydrolase activity and esculin hydrolysis was an effective rapid technique to screen for aquatic environmental V. cholerae. This technique provided 100% sensitivity and ≥70% specificity.     

Print news coverage of cancer: What prevention messages are conveyed when screening is newsworthy?

Background: Americans are generally favorable towards cancer screening, but fatalistic about cancer prevention. News coverage shapes perceptions of cancer control in meaningful ways, but there is little consensus as to the impact of news on our understanding of and engagement in cancer screening practices. Our analysis of cancer screening-related print news coverage during a four month period in 2005 suggests that the newsworthiness of new screening technologies may undermine public confidence in currently available and effective secondary prevention programs, while promoting tests whose effectiveness is debated or not yet established. Methods and results: We conducted a structured text analysis of 517 cancer-related news articles from 15 leading daily newspapers and a subsequent qualitative analysis of the 79 screening news articles. Screening articles were analyzed for content related to criteria for screening effectiveness. Content patterns for each type of screening and cancer were also noted. News coverage consistently conveyed screening as important and highlighted the need to protect and expand access to screening. At the same time, to the extent that story content was framed by the newsworthiness of new tests and technologies this often indirectly called into question effective and established protocols and programs without providing any actionable alternative. Conclusion: This analysis revealed unexpected messages about screening that are potentially problematic for cancer control. The cancer control community should continue efforts to understand and shape news coverage of screening in order to promote balanced and action-oriented content. Research has shown that Americans hold conflicting views regarding cancer—having a favorable opinion of screening while simultaneously feeling fatalistic about prevention. Our analysis of print news stories on cancer screening suggests that the determination of screening's “newsworthiness” is related to newly developed tests and protocols, which may create demand for new tests whose effectiveness is unknown and undermine confidence in established and effective screening programs.     

Effectiveness of five antidandruff cosmetic formulations against planktonic cells and biofilms of dermatophytes

This study aimed to investigate the in vitro antifungal effectiveness of five different formulations against dandruff and ringworm dermatophytes. Candida albicans was also included in our assays. Fungal susceptibility tests were performed with planktonic cells and biofilms of reference strains. Microbiological and physicochemical quality parameters were assessed for all formulations. Our data indicated that the formulations were effective against the dermatophytes strains, and to our knowledge, the effectiveness of cosmetic formulations against fungal biofilms is shown for the first time. The formulations were considered effective against the explored dermatophytes and were considered safe given the adequate microbiological and physicochemical characteristics shown in the proposed assays.     

Comparative effect of three rodenticides warfarin,bromadiolone and brodifacoum on the Indian field mouse,Mus booduga gray

Three anticoagulant rodenticides, warfarin, bromadiolone and brodifacoum, were evaluated in the laboratory for their activity against the Indian field mouse, Mus booduga. In oral intubation studies M. booduga was found to be more susceptible to bromadiolone and brodifacoum than warfarin. Feeding studies with 0.005% bromadiolone and brodifacoum baits produced 83% mortality after a single day's feeding while a similar mortality was achieved with 0.025% warfarin only after 6 days of consecutive feeding. The anticoagulant baits were less palatable than the plain (unpoisoned) bait. Laboratory feeding tests confirmed that 0.005% of the active ingredient would be an effective bait concentration for field use of both bromadiolone and brodifacoum. The single-feed potency of bromadiolone and brodifacoum indicate that these rodenticides may be more effective and economical than warfarin in the field.     

Malacorhinus irregularis for biological control of Mimosa pigra: host-specificity,life cycle,and establishment in Australia

Malacorhinus irregularis Jacoby (Coleoptera: Chrysomelidae: Galerucinae: Galerucini), from Mexico is identified as a potential biological control agent for Mimosa pigra L. (Mimosaceae), a serious weed of northern Australia and Asia. The adults feed on leaves of the host, and the larvae develop on seedlings, roots, and perhaps other plant parts. The damage to the target plant is substantial, indicating that this insect could be an effective control agent. Host-specificity tests examined the suitability of seedlings and leaves for larval development, and suitability of leaves for adult feeding. In no-choice tests, no larval development occurred on any of the 81 test plant species other than M. pigra. The extent of adult feeding on the test plants was negligible in the tests using a choice-minus-control design, being less than 1% of that which occurred on M. pigra. We conclude that M. irregularis is a specialist on its host and the risk associated with its release in Australia is low. It was released in infestations of M. pigra in the Northern Territory of Australia in 2000. Establishment and abundance was monitored at one site where the number and distribution of adult beetles fluctuated widely as soil moisture conditions varied through the seasons. Adults were found for two years after release and local defoliation of plants was attributed to this species. Although only limited observations were made, adult feeding was not recorded from Neptunia major (Benth). Windler plants growing in close proximity to M. pigra, indicating specificity under field conditions.     

Nisin-activated hydrophobic and hydrophilic surfaces: assessment of peptide adsorption and antibacterial activity against some food pathogens

An effective antimicrobial packaging or food contact surface should be able to kill or inhibit micro-organisms that cause food-borne illnesses. Setting up such systems, by nisin adsorption on hydrophilic and hydrophobic surfaces, is still a matter of debate. For this purpose, nisin was adsorbed on two types of low-density polyethylene: the hydrophobic native film and the hydrophilic acrylic acid-treated surface. The antibacterial activity was compared for those two films and it was highly dependent on the nature of the surface and the nisin-adsorbed amount. The hydrophilic surfaces presented higher antibacterial activity and higher amount of nisin than the hydrophobic surfaces. The effectiveness of the activated surfaces was assessed against Listeria innocua and the food pathogens Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. S. aureus was more sensitive than the three other test bacteria toward both nisin-functionalized films. Simulation tests to mimic refrigerated temperature showed that the films were effective at 20 and 4 °C with no significant difference between the two temperatures after 30 min of exposure to culture media.     

Chemicals for preventing moulding in damp hay

Fewer than one third of more than 100 chemicals tested prevented moulding when 0.5% of active ingredient was added to hay containing 35% water or, alternatively, when 0.02% of active ingredient was added with 0.2% propionic acid or ammonium propionate. Chemicals which prevented moulding in these tests when used alone included aliphatic acids with 2–6 carbon atoms, sorbic acid, short chain aldehydes and phenols, propionic acid, fully or half-neutralized with ammonia, and 8-quinolinol and its derivatives. Formic acid, aliphatic acids with 7–9 carbon atoms, longer chain aldehydes and some fungicides delayed moulding for one to two weeks. Only formaldehyde, 8-quinolinol and its derivatives, and p-nitrophenol increased the activity of 0.2% propionic acid. Although the effective doses of propionic acid, ammonium propionate, and propionic acid, half-neutralised with ammonia, were similar, there was evidence that the presence of free acid in the formulation aided redistribution to overcome undertreatment of pockets in the hay. Further tests of 2-phenyl phenol, phenyl propionate and 8-quinolinol showed that the latter was the best candidate for development. Fungi of the Aspergillus glaucus group were first to colonise most tests that failed, indicating their high degree of tolerance of a wide range of chemicals, and their value as test organisms for prospective preservatives.     

Formulation of a soil biofungicide for control of damping-off of Chinese cabbage (Brassica chinensis) caused by Rhizoctonia solani

A granulate biofungicide named PBGG was developed by combining Pseudomonas boreopolis with Brassica seed pomace, glycerin and sodium alginate. Application of 1.0% (w/w) of PBGG to the soil infested with Rhizoctonia solani AG-4 significantly reduced the percentage of colonization of cabbage seeds by the pathogen and stimulated proliferations of actinomycetes. Among Streptomyces populations, Streptomyces padanus (strain SS-07) and Streptomyces xantholiticus (strain SS-09) were the two most effective strains with strong antagonistic effects to R. solani. Application of 1% (w/w) PBGG in soil significantly increased population densities of S. padanus and S. xantholiticus. Treating soil with S. padanus (strain SS-07) or S. xantholiticus (strain SS-09) alone or in combination with 1% (w/w) PBGG significantly reduced the percentage of colonization of cabbage seeds by R. solani, compared to untreated controls. S. padanus was the most effective agent in reducing the percentage of seed colonization by the pathogen. Results of greenhouse tests showed that the most effective treatment was the amendment of pathogen-infested soil by S. padanus + 1% (w/w) PBGG which resulted in a disease incidence of 6.5–8.6%, compared to 27.8–31.7% for the treatment of S. xantholiticus + 1% (w/w) PBGG, 36.9–38.6% for the treatment of 1% (w/w) PBGG alone, and 61.8–64.8% for the treatment of control (unamended soil). Results of greenhouse and field tests also showed that soil amendment of 1% (w/w) PBGG alone or 1% (w/w) PBGG mixed with S. padanus (strain SS-07) or S. xantholiticus (strain SS-09) was not harmful to seed germination of Chinese cabbage. The study suggests that amendment of R. solani infested soil with S. padanus + 1% (w/w) PBGG prior to sowing is an effective method for control of damping-off of Chinese cabbage.     

The Escherichia coli WP2/WP100 rec assay for detection of potential chemical carcinogens

46 chemicals of various classes and structures, including 30 known animal carcinogens, were evaluated for genotoxic effects using the Escherichia coli rec assay with strains WP2 (wild-type) and WP100 (uvrA⁻¹recA⁻) in qualitative and quantitative spot tests and in quantitative suspension tests. The rec assay detected 17 of 30 known carcinogens as genotoxic agents, including mitomycin C and diethylnitrosamine, both negative in the Salmonella/Ames test as utilized in these studies. The rec assay in conjunction with the Salmonella/Ames test 30 known carcinogens as genotoxic agents. Azo/aminoazo carcinogens showed little genotoxicity, and the aromatic amine 2-acetylaminofluorene was non-genotoxic in the rec assay. The rec assay was more effective than pol tests with E. coli strains W3110/p3478 and strains WP2/WP67. Effectiveness of the rec assay was related to the DNA repair-defective nature of the uvrA⁻ recA⁻ genotype of strain WP100.     

Potential for cell culture techniques as a wildlife management tool for screening primary repellents

The identification of new chemical repellents for wildlife damage management is impeded by the need to perform cumbersome and expensive behavioral tests. Here, we report the development of in vitro cell culture methods to increase the speed and efficiency of repellent screening while reducing costs, as well as the number of animals necessary for research. Our methods exploit the fact that effective primary repellents depend on the stimulation of pain receptors. We cultured trigeminal nociceptors (pain receptors) from Norway rat (Rattus norvegicus, laboratory strain), white leghorn chicken (Gallus gallus), coyote (Canis latrans), white-tailed deer (Odocoileus virginianus) and Canada goose (Branta canadensis), and then applied digital fluorescence microscopy to measure changes in intracellular calcium (an index of cellular activation) in response to applications of known and effective repellents. Capsaicin, bradykinin and acetylcholine were more effective stimuli for rat, coyote, and deer neurons than cells from chicken.     

Genetic control of effective juvenile resistance to leaf rust in collection samples of Triticum aestivum L.

Of 153 samples reported to be resistant to leaf rust (Puccinia recondita Rob. ex. Desm.), only 70 were not affected by a complex P. recondita population. According to phytopathological tests (inoculation with test clones), 14 samples possessed the Lr19 gene; 36, the Lr24 gene; 1, the Lr41 gene; and 19 presumably had the Lr9 gene. The presence of these genes for resistance was confirmed by hybridological analysis for 26 samples. Of 28 samples reported to carry new effective genes for resistance other than the known genes, 23 were susceptible to the P. recondita population. In four of the other five samples, resistance proved to be controlled by known genes. Possible causes of false identification of new effective genes for leaf rust resistance in wheat are discussed.     

The effect of root architecture on the shearing resistance of root-permeated soils

This paper aims to investigate the effect of the root architecture on the shear strength increment provided by plant roots in the soil. In situ shear tests were conducted for this purpose. Five plant species – Hibiscus tiliaceus L. (Linden hibiscus), Mallotus japonicus (Thunb.) Muell.-Arg. (Japanese Mallotus), Sapium sebiferum (L.) Roxb. (Chinese tallow tree), Casuarina equisetifolia L. (ironwood), and Leucaena leucocephala (Lam.) (white popinac) – were used in this study. Tensile tests on roots of various diameters and surveys on the root system structure were carried out for each of the plant species tested. The shear strength increments (ΔS) provided by the roots of Linden hibiscus, Japanese Mallotus, Chinese tallow tree, ironwood, and white popinac were 0.34t_R, 0.462t_R, 0.688t_R, 0.3t_R, and 0.87t_R, respectively, when t_R was estimated on the basis of the tensile root strength crossing through the shear plane. The shear strength increment provided by plant roots with conspicuous oblique and vertical roots was greater than that of root structures in which lateral roots were dominant. In comparison with other types of root architecture, the R-type root architecture was found to be the most effective root system against shear failure in the soil. Its shear strength increment was slightly greater than that with the V-type root architecture, followed by the VH-type root architecture. The shear strength increment provided by plants with the H-type root architecture was less effective than that contributed by plant species with other types of root architecture.     

Evidence for search image in blackbirds Turdus merula L.: long-term learning

The feeding behaviour of free-flying and captive blackbirds Turdus merula L. was observed over a number of days to investigate their ability to see cryptic food. Sequences of eight tests which contained equal numbers of ‘cryptic’ and ‘conspicuous’ tests were presented to the birds of the first two experiments. The blackbirds in experiment 1 increased their feeding rate for both cryptic and conspicuous food, which suggests that search images were not acquired but that the physical acts of feeding were perfected (or that they altered their acceptance of green food). In contrast, the ‘residual search time’ (the bird's total search time minus handling and movement times) decreased over the series of four tests with cryptic green prey, but remained constant over the four tests with conspicuous prey (experiment 2). The blackbirds exploited the cryptic prey using their previous experience of searching for such food. This suggests that search images can be effective over eight feeding sessions, spanning 4–30 days. Similar results were obtained over a 9-day period with four juvenile blackbirds in captivity (experiment 3). With experience they also became expert in their assessment of backgrounds set up without prey.     

Evaluation of the single radial diffusion technique for detection of nuclear polyhedrosis virus (NPV) infection in Heliothis zea

The single radial diffusion test is an effective method for detection of nuclear polyhedrosis virus infection in Heliothis zea larvae. Virus antigens were detected in some instances 48 hr after the larvae were exposed to virus. Most larvae tested positively for virus antigens 72 hr after exposure to the virus. The tests could be read within 4 hr if the incubation temperature was 35°C, and within 24 hr at 22°C.     

Inhibition of Swarming of Proteus by Sodium Tetradecyl Sulfate, β-Phenethyl Alcohol,and p-Nitrophenylglycerine

The effects of sodium tetradecyl sulfate (STS), β-phenethyl alcohol (PEA), and p-nitrophenylglycerol (PNPG) on motility, swarming, flagellation, and growth of Proteus were examined. Growth-inhibitory concentrations (GIC) and swarming-inhibitory concentrations (SIC) were determined. A characterization of the swarming-inhibitory efficacy of these compounds was based on their GIC/SIC ratio and their concentration inhibition curves. Using the homologous series of sodium alkyl sulfates as a standard reference, we showed that PNPG was more effective than STS, which was the most effective of the homologous series. PEA was less effective than sodium decyl sulfate but more effective than sodium octyl sulfate. Motility tests in liquid medium and electron microscope investigations indicated that the modes of action of the three compounds, all of which effectively inhibit the swarming of Proteus, are different. Whereas STS and PEA inhibit swarming by inhibition of motility, PNPG seems to act on the swarming mechanism sensu strictori, without impairment of motility. STS immobilizes by inhibition of flagellum formation or by some lytic action on the flagella already synthesized. PEA acts by impairing flagellar function, but leaves the flagella morphologically intact.     

Inhibition of Swarming of Proteus by Sodium Tetradecyl Sulfate, beta-Phenethyl Alcohol, and p-Nitrophenylglycerine

The effects of sodium tetradecyl sulfate (STS), β-phenethyl alcohol (PEA), and p-nitrophenylglycerol (PNPG) on motility, swarming, flagellation, and growth of Proteus were examined. Growth-inhibitory concentrations (GIC) and swarming-inhibitory concentrations (SIC) were determined. A characterization of the swarming-inhibitory efficacy of these compounds was based on their GIC/SIC ratio and their concentration inhibition curves. Using the homologous series of sodium alkyl sulfates as a standard reference, we showed that PNPG was more effective than STS, which was the most effective of the homologous series. PEA was less effective than sodium decyl sulfate but more effective than sodium octyl sulfate. Motility tests in liquid medium and electron microscope investigations indicated that the modes of action of the three compounds, all of which effectively inhibit the swarming of Proteus, are different. Whereas STS and PEA inhibit swarming by inhibition of motility, PNPG seems to act on the swarming mechanism sensu strictori, without impairment of motility. STS immobilizes by inhibition of flagellum formation or by some lytic action on the flagella already synthesized. PEA acts by impairing flagellar function, but leaves the flagella morphologically intact.     

Clostridium difficile testing algorithms: What is practical and feasible?

There has been renewed interest in the laboratory diagnosis of Clostridium difficile infections due in large measure to the increase in both numbers and severity of cases of this disease. For the past two decades, enzyme-immunoassays (EIAs) for the detection of first C. difficile toxin A and then toxins A and B have been the most widely used diagnostic test for diagnosis of C. difficile infections. Recently this diagnostic approach has been called into question by the recognition that a screening test which detects glutamate dehydrogenase, a cell wall antigen of C. difficile, was significantly more sensitive than toxins A and B EIAs making it an effective screening test for C. difficile infection. Although sensitive, GDH lacks specificity and so if this test was utilized, a confirmatory test to differentiate false positives from true positives was needed. Studies to date have used cytotoxin neutralization or toxigenic culture as confirmatory tests but both of these have their limitations. A testing algorithm using rapid immunochromatographic devices for detection of GDH and toxins A and B as screening tests will give an accurate test result in approximately 90% of specimens within one hour when using cytotoxin neutralization as a reference method. For the other 10% of specimens, a third test would be needed in the algorithm. This test could be cytotoxin neutralization, toxigenic culture, or PCR for toxin or toxin operon genes.     

Serodiagnosis of Tuberculosis in Asian Elephants (Elephas maximus) in Southern India: A Latent Class Analysis

Background

Mycobacterium tuberculosis, a causative agent of chronic tuberculosis disease, is widespread among some animal species too. There is paucity of information on the distribution, prevalence and true disease status of tuberculosis in Asian elephants (Elephas maximus). The aim of this study was to estimate the sensitivity and specificity of serological tests to diagnose M. tuberculosis infection in captive elephants in southern India while simultaneously estimating sero-prevalence.

Methodology/Principal Findings

Health assessment of 600 elephants was carried out and their sera screened with a commercially available rapid serum test. Trunk wash culture of select rapid serum test positive animals yielded no animal positive for M. tuberculosis isolation. Under Indian field conditions where the true disease status is unknown, we used a latent class model to estimate the diagnostic characteristics of an existing (rapid serum test) and new (four in-house ELISA) tests. One hundred and seventy nine sera were randomly selected for screening in the five tests. Diagnostic sensitivities of the four ELISAs were 91.3–97.6% (95% Credible Interval (CI): 74.8–99.9) and diagnostic specificity were 89.6–98.5% (95% CI: 79.4–99.9) based on the model we assumed. We estimate that 53.6% (95% CI: 44.6–62.8) of the samples tested were free from infection with M. tuberculosis and 15.9% (97.5% CI: 9.8 - to 24.0) tested positive on all five tests.

Conclusions/Significance

Our results provide evidence for high prevalence of asymptomatic M. tuberculosis infection in Asian elephants in a captive Indian setting. Further validation of these tests would be important in formulating area-specific effective surveillance and control measures.     

Suppressive effect of Bacillus subtilis and it's products on phytopathogenic microorganisms

Bacteria isolated from suppressive composts which showed clear zones inhibitory to the growth of phytopathogenic fungi in vitro on agar plates were identified to be Bacillus subtilis. The suppressiveness of the culture broth of these bacteria became obvious in in vivo tests, and the efficacy of the broth to phytopathogens was equivalent to that of available chemicals. The suppressive spectrum of the broth of this bacteria was broad enough to be effective not only to phytopathogenic fungi but also to bacteria. As a suppressive substance, an antibiotic of the iturin group was purified from the broth and identified. MIC values of each component of the iturin to several phytopathogens were determined.