Incidence of Agrobacterium tumefaciens Biovar 1 in and on 'Paradox' (Juglans hindsii × Juglans regia) Walnut Seed Collected from Commercial Nurseries.

The walnut rootstock 'Paradox' (Juglans hindsii × J. regia) is susceptible to Agrobacterium tumefaciens, which often results in a high incidence of crown gall in nursery or walnut production orchards. Though A. tumefaciens is susceptible to the commonly used preplant soil fumigants, crown gall incidence can rise above acceptable levels. We examined the ability of Paradox seed to acquire A. tumefaciens as a function of harvest method used prior to planting. Over a 2-year period at two participating commercial nurseries, Paradox seed were collected directly from the mother tree without contacting the soil or gathered after sitting on the orchard floor for up to 28 days. A. tumefaciens was never detected in or on the 2,650 seeds collected directly from the mother tree. Both virulent and avirulent A. tumefaciens strains were detected in and on the husk of nuts incubated on the orchard floor at a frequency directly proportional to the time spent on the orchard floor. Regardless of A. tumefaciens contamination in or on the husk, A. tumefaciens was never detected in the seed interior. Avoiding soilborne populations of A. tumefaciens at the time of seed collection will play an important role in managing crown gall.

An improved regulatory sampling method for mapping and representing plant disease from a limited number of samples.

A key challenge for plant pathologists is to develop efficient methods to describe spatial patterns of disease spread accurately from a limited number of samples. Knowledge of disease spread is essential for informing and justifying plant disease management measures. A mechanistic modelling approach is adopted for disease mapping which is based on disease dispersal gradients and consideration of host pattern. The method is extended to provide measures of uncertainty for the estimates of disease at each host location. In addition, improvements have been made to increase computational efficiency by better initialising the disease status of unsampled hosts and speeding up the optimisation process of the model parameters. These improvements facilitate the practical use of the method by providing information on: (a) mechanisms of pathogen dispersal, (b) distance and pattern of disease spread, and (c) prediction of infection probabilities for unsampled hosts. Two data sets of disease observations, Huanglongbing (HLB) of citrus and strawberry powdery mildew, were used to evaluate the performance of the new method for disease mapping. The result showed that our method gave better estimates of precision for unsampled hosts, compared to both the original method and spatial interpolation. This enables decision makers to understand the spatial aspects of disease processes, and thus formulate regulatory actions accordingly to enhance disease control.

Cationic Surfactants: Potential Surface Disinfectants to Manage Agrobacterium tumefaciens Biovar 1 Contamination of Grafting Tools.

Nursery production of walnut seedlings is a 2-year process, during which crown gall, caused by Agrobacterium tumefaciens, often develops at grafting wounds. In this study, the spread of crown gall via contaminated tools and the efficacy of several disinfectants against A. tumefaciens were demonstrated. The cationic surfactants benzalkonium chloride (BC), cetyltrimethylammonium bromide (CTAB), and Physan 20 eliminated 100% of the A. tumefaciens population in water suspensions treated at 7, 5, and 2 ppm, respectively. Sodium hypochlorite eliminated 100% of the A. tumefaciens population at 0.5 ppm. Sodium hypochlorite efficacy, however, was reduced by 64% in the presence of total solids (0.7 g/ml) which are commonly found in field situations. At similar concentrations of total solids, the efficacy of cationic surfactants decreased, on average, by only 13%. The minimum effective treatment needed to eliminate A. tumefaciens on infested scalpels was a 5-s exposure to BC or CTAB at 5,000 ppm (0.5%). Infested scalpels treated with BC or CTAB at less than 5,000 ppm caused gall formation in 14 ± 7% of cuts made on Datura stramonium stems. This was significantly less than the tumor incidence (100%) in cuts made with inoculated blades not treated BC or CTAB.

Role of Systemic Agrobacterium tumefaciens Populations in Crown Gall Incidence on the Walnut Hybrid Rootstock 'Paradox'.

Greater than 75% of English walnut production in the United States occurs on the walnut rootstock Juglans hindsii × J. regia 'Paradox', which is highly susceptible to infection by Agrobacterium tumefaciens. When seed were germinated and grown in the presence of A. tumefaciens, in the absence of wounding, 94% of the seedlings exhibited tumors while 89% contained systemic A. tumefaciens populations. When seedlings were wound inoculated, A. tumefaciens established endophytic populations in stem tissue and often migrated from the site of infection. Distribution of A. tumefaciens in the stem was random and may exhibit seasonal variation. A. tumefaciens populations in root tissue were more readily detected than in stem tissue and may serve as a reservoir for subsequent infection of the aerial portions of the tree. Importantly, 7% of inoculated, asymptomatic seedlings contained endophytic populations of A. tumefaciens. In all, 17% of seedlings inoculated as seeds developed galls at secondary stem-wound sites. These results provide an ecological and epidemiological foundation upon which to modify existing tree-handling practices in both nursery and orchard production environments to manage crown gall incidence.

Cutaneous T cell lymphoma-mycosis fungoides and Sezary syndrome: an update.

Mycosis fungoides (MF) is the most common form of cutaneous T cell lymphoma (CTCL) and, for unclear reasons, its incidence appears to be increasing. Due to significant differences in biological behavior, cutaneous T cell lymphomas have recently been reclassified. MF and Sezary syndrome (SS) are now separately classified as indolent and aggressive CTCLs, respectively. The cause of MF and SS remains elusive. Because establishing the diagnosis of MF, particularly in early stages of disease, is often difficult, a guideline with clinical and histological diagnostic criteria has recently been proposed. With the exception of very early stage disease, no cure is available. However, the number of available therapeutic options has increased considerably in recent years, and partial and complete remissions are achievable. Prognosis and selection of appropriate therapy largely depends on stage of disease. A detailed practice guideline with an algorithmic, stage-based approach to therapy has recently been put forth and will likely aid clinicians in managing patients with MF and SS. Despite the indolent nature in most individuals, the disease has a tremendous psychological impact, not only because of the visible nature of the skin lesions, but also due to the rarity of the disease and its chronicity. Knowledge of this disease, therapeutic options and expectations of therapy will greatly enhance care of afflicted patients.

Modeling of Relationships Between Weather and Septoria tritici Epidemics on Winter Wheat: A Critical Approach.

ABSTRACT Two models for predicting Septoria tritici on winter wheat (cv. Riband) were developed using a program based on an iterative search of correlations between disease severity and weather. Data from four consecutive cropping seasons (1993/94 until 1996/97) at nine sites throughout England were used. A qualitative model predicted the presence or absence of Septoria tritici (at a 5% severity threshold within the top three leaf layers) using winter temperature (January/February) and wind speed to about the first node detectable growth stage. For sites above the disease threshold, a quantitative model predicted severity of Septoria tritici using rainfall during stem elongation. A test statistic was derived to test the validity of the iterative search used to obtain both models. This statistic was used in combination with bootstrap analyses in which the search program was rerun using weather data from previous years, therefore uncorrelated with the disease data, to investigate how likely correlations such as the ones found in our models would have been in the absence of genuine relationships.

Quantification of raindrop kinetic energy for improved prediction of splash-dispersed pathogens.

ABSTRACT An electronic sensor, based on a piezoelectric transducer, was tested in the laboratory using simulated raindrops, and in natural rainfall. Data were also collected for splash dispersal using tracer dyes in laboratory experiments and the Long Ashton splashmeter in field experiments. Droplets impacting on sensor produce sound waves that are detected by an omnidirectional microphone sealed within an acoustic chamber. An electrical charge, proportional to the sound wave, is produced by the microphone and is converted to a categorical scale and then stored to provide an accumulation of impacts over a specified period of time. Calibration of the sensor was done using single-droplet impacts of known mass and impacting velocity. A linear relationship was shown between the categorical scale and the kinetic energy of impacting droplets (adjusted r(2) = 0.99). The best relationship fitted between splash dispersal from dye cup, and kinetic energy was a second-order polynomial (adjusted r(2) > 0.99). Splash height, recorded by the Long Ashton splashmeter during 41 natural rainfall events, was correlated closely with sensor output (adjusted r(2) = 0.87). Our studies indicate that the sensor provides quantitative data which could be incorporated into disease management systems to provide estimates of inoculum dispersal gradients within crop canopies.

Psychiatric morbidity in patients with systemic lupus erythematosus.

We investigated psychiatric morbidity in patients with systemic lupus erythematosus, in a hospital-based study. Thirty patients (23 consecutive out-patients and seven unselected in-patients) were prospectively assessed by a multidisciplinary team for the presence of psychiatric disorders and disease activity. Psychiatric assessment was done with structured interviews. Demographic information was recorded in a structured proforma; all the patients completed the Presumptive Stressful Life Event Scale. A close relative was interviewed in every case. Patients who had psychiatric disorders were compared with the rest with respect to demographic variables, lupus disease activity, use of steroids, and stressful life events. We found a 50% prevalence of psychiatric disorders. The patients with psychiatric disorders were similar to those who had no psychopathology with respect to age, sex, duration of illness, lupus activity and the use of steroids. However, they had experienced more stressful life events in the last year.

Homobotcinolide: a biologically active natural homolog of botcinolide from Botrytis cinerea.

A novel natural product exhibiting biological activity was isolated from a strain of Botrytis cinerea that had infected raspberry fruit (Rubus ideaus). Liquid fermentation and bioassay-directed fractionation of the organism yielded a compound with molecular formula C22H38O8 that is trivially named homobotcinolide. It significantly inhibited etiolated wheat coleoptile growth. Greenhouse-grown bean, corn, and tobacco plants were also affected by exogenous application of homobotcinolide, severe chlorosis and necrosis being exhibited in corn. The compound is a polyhydroxylated nonalactone esterified with 4-hydroxy-2-decenoic acid.

Total joint arthroplasty in a predominantly African-American population. Part two: Hip arthroplasty.

This second part of a two-part series examines total hip arthroplasty in an African-American population. Total hip arthroplasty has revolutionized orthopedic surgery since it began more than two decades ago. The quality and durability of results have enabled patients to pursue a more normal lifestyle, greatly relieved of their pain. Although many studies have reviewed the long-term results of total hip arthroplasty, none have addressed the results in a predominantly African-American population. This study retrospectively reviews the results of total hip arthroplasty in 62 African-American patients. Patients' attitudes toward this surgery, their co-morbid conditions, complications, and results were examined with regard to activity level and acceptance of the procedure.

Koninginin C: a biologically active natural product from Trichoderma koningii.

Koninginin C, a congener of koninginins A and B, was isolated from Trichoderma koningii fermented on a shredded wheat medium. The compound inhibited the growth of etiolated wheat coleoptiles by 100% at 10(-3) M. It was a fine, white crystalline substance with a molecular formula of C16H28O4 and a melting point of 70-72 degrees C.

Cyanine dye labeling reagents--carboxymethylindocyanine succinimidyl esters.

Ten carboxymethylindocyanine dyes which form the basis of a new series of fluorescent probes have been synthesized and converted into succinimidyl active esters for fluorescent labeling of proteins or other amino-containing substances. Fluorescence emission maxima for members of the series range from 575 to 780 nm. Hydrophilic, water-soluble reagents have been obtained which yield labeled antibodies with little tendency to form precipitates. The fluorescence intensities achieved are higher than those produced by labeling with the cyanine isothiocyanates described previously (Mujumdar et al.: Cytometry 10:11-19, 1989). The utility of these reagents has been demonstrated in antibody labeling for two-color immunofluorescent imaging of internal structures in a mammalian cell and for two-color flow-cytometry experiments. The use of values of chromophore-equivalent weight (W/Ceq), calculated from quantitative absorption data on dye samples, is proposed as an aid in formulating labeling procedures.

Making childhood asthma management education happen in the community: translating health behavioral research into local programs.

The public health benefits of research can be realized only if proven new techniques are translated into readily usable processes and materials and widely adopted by professionals and patients alike. To accomplish this, a systematic technology transfer process is needed. One recent outcome of health behavior research has been identification of the skills needed by children and parents to effectively manage childhood asthma. Methods for teaching these skills were tested on hundreds of families in a variety of health care settings. They were then packaged in program manuals that guide health professionals through the teaching process and provide all necessary materials for conducting sessions. The resulting four programs teach attack prevention and control skills. They also emphasize coping skills and help families come to terms with the behavioral factors that impinge on asthma management and affect compliance with medical advice. A technology transfer project for getting initial community adoption of these programs is described. The evolution of the project, including the development of the programs themselves, packaging considerations, establishment of a unique partnership for dissemination, development of a model workshop for stimulating health professionals, implementation of programs, and follow up and evaluation, is described. Successful elements are identified at each step.