Temporal Dynamics of Wheat Blast Epidemics and Disease Measurements Using Multispectral Imagery.

Wheat blast is a devastating disease caused by the Triticum pathotype of Magnaporthe oryzae. M. oryzae Triticum is capable of infecting leaves and spikes of wheat. Although symptoms of wheat spike blast (WSB) are quite distinct in the field, symptoms on leaves (WLB) are rarely reported because they are usually inconspicuos. Two field experiments were conducted in Bolivia to characterize the change in WLB and WSB intensity over time and determine whether multispectral imagery can be used to accurately assess WSB. Disease progress curves (DPCs) were plotted from WLB and WSB data, and regression models were fitted to describe the nature of WSB epidemics. WLB incidence and severity changed over time; however, the mean WLB severity was inconspicuous before wheat began spike emergence. Overall, both Gompertz and logistic models helped to describe WSB intensity DPCs fitting classic sigmoidal shape curves. Lin's concordance correlation coefficients were estimated to measure agreement between visual estimates and digital measurements of WSB intensity and to estimate accuracy and precision. Our findings suggest that the change of wheat blast intensity in a susceptible host population over time does not follow a pattern of a monocyclic epidemic. We have also demonstrated that WSB severity can be quantified using a digital approach based on nongreen pixels. Quantification was precise (0.96 < r> 0.83) and accurate (0.92 < ρ > 0.69) at moderately low to high visual WSB severity levels. Additional sensor-based methods must be explored to determine their potential for detection of WLB and WSB at earlier stages.

QTL mapping for yield and lodging resistance in an enhanced SSR-based map for tef.

Tef is a cereal crop of cultural and economic importance in Ethiopia. It is grown primarily for its grain though it is also an important source of fodder. Tef suffers from lodging that reduces both grain yield and quality. As a first step toward executing a marker-assisted breeding program for lodging resistance and grain yield improvement, a linkage map was constructed using 151 F(9) recombinant inbred lines obtained by single-seed-descent from a cross between Eragrostis tef and its wild relative Eragrostis pilosa. The map was primarily based on microsatellite (SSR) markers that were developed from SSR-enriched genomic libraries. The map consisted of 30 linkage groups and spanned a total length of 1,277.4 cM (78.7% of the genome) with an average distance of 5.7 cM between markers. This is the most saturated map for tef to date, and for the first time, all of the markers are PCR-based. Using agronomic data from 11 environments and marker data, it was possible to map quantitative trait loci (QTL) controlling lodging, grain yield and 15 other related traits. The positive effects of the QTL identified from the wild parent were mainly for earliness, reduced culm length and lodging resistance. In this population, it is now possible to combine lodging resistance and grain yield using a marker-assisted selection program targeting the QTL identified for both traits. The newly developed SSR markers will play a key role in germplasm organization, fingerprinting and monitoring the success of the hybridization process in intra-specific crosses lacking distinctive morphological markers.

A comparison between genotyping-by-sequencing and array-based scoring of SNPs for genomic prediction accuracy in winter wheat.

The utilization of DNA molecular markers in plant breeding to maximize selection response via marker-assisted selection (MAS) and genomic selection (GS) has revolutionized plant breeding. A key factor affecting GS applicability is the choice of molecular marker platform. Genotyping-by-sequencing scored SNPs (GBS-scored SNPs) provides a large number of markers, albeit with high rates of missing data. Array scored SNPs are of high quality, but the cost per sample is substantially higher. The objectives of this study were 1) compare GBS-scored SNPs, and array scored SNPs for genomic selection applications, and 2) compare estimates of genomic kinship and population structure calculated using the two marker platforms. SNPs were compared in a diversity panel consisting of 299 hard winter wheat (Triticum aestivum L.) accessions that were part of a multi-year, multi-environments association mapping study. The panel was phenotyped in Ithaca, Nebraska for heading date, plant height, days to physiological maturity and grain yield in 2012 and 2013. The panel was genotyped using GBS-scored SNPs, and array scored SNPs. Results indicate that GBS-scored SNPs is comparable to or better than Array-scored SNPs for genomic prediction application. Both platforms identified the same genetic patterns in the panel where 90% of the lines were classified to common genetic groups. Overall, we concluded that GBS-scored SNPs have the potential to be the marker platform of choice for genetic diversity and genomic selection in winter wheat.

Genotyping live fish larvae: Non-lethal and noninvasive DNA isolation from 3-5 day old hatchlings.

Genotyping fish larvae is a valuable technique for numerous fields of study. While methods for collecting DNA from early stage larvae have been published, a non-lethal, non-invasive genotyping protocol for hatchlings that is amenable to high-throughput approaches is desirable. Here, we describe a method to individually genotype live, free-swimming, early fish larvae by characterizing their environmental DNA (eDNA). We demonstrate the utility of the method by assigning parentage to a sample (n = 50) of 3-5-day-old sheepshead minnow (Cyprinodon variegatus) larvae hatchlings, with very high rates of genotyping success (98%) and survival (92%) using mitochondrial and microsatellite DNA data. This method could be easily adapted to characterize early fish larvae from other model and non-model fish species, such as Danio rerio (zebrafish) and Medaka medaka.

Regression of oral leukoplakia with alpha-tocopherol: a community clinical oncology program chemoprevention study.

BACKGROUND: Oral leukoplakia is an important model for developing chemoprevention approaches for lesions in the upper aerodigestive tract. These lesions most often result from exposure to carcinogens such as tobacco and alcohol and may precede development of invasive cancer. The potent antioxidant alpha-tocopherol (vitamin E) has prevented the development of cancers of the oral cavities in animal models. PURPOSE: The objectives of this study were to evaluate the toxicity and efficacy of alpha-tocopherol in patients with oral leukoplakia and to assess the feasibility of performing chemoprevention trials through the network of the Community Clinical Oncology Program (CCOP). METHODS: A single-arm phase II study using the nontoxic agent alpha-tocopherol to treat oral premalignant leukoplakia was performed at seven institutions affiliated with the CCOP through The University of Texas M. D. Anderson Cancer Center. Patients with symptomatic leukoplakia or dysplasia were treated orally with alpha-tocopherol (400 IU) twice daily for 24 weeks. Follow-up was performed at 6, 12, and 24 weeks after the start of treatment to assess toxicity and response, and serum alpha-tocopherol levels were determined at baseline and at 6 and 24 weeks. RESULTS: Of the 43 patients who have completed 24 weeks of treatment, 20 (46%) had clinical responses and nine (21%) had histologic responses. Mean serum alpha-tocopherol levels were 16.1 micrograms/mL at baseline and increased to 34.29 micrograms/mL after 24 weeks of treatment. Patient-recorded drug calendars, as well as serum drug levels, indicated excellent patient compliance; an average of 95% of the prescribed pills were taken. Treatment was extremely well tolerated; no grade 3 or 4 toxic effects were reported. CONCLUSIONS: Administration of alpha-tocopherol resulted in both clinical and histologic responses in premalignant leukoplakia lesions. The study also demonstrated that chemoprevention trials can be performed through the CCOP. The major problems were that a high percentage of patients were not assessable for response, some patients withdrew because expenses were not reimbursable, and there was limited participation within the CCOP network. These problems may reflect difficulties inherent in the implementation of multi-institutional chemoprevention trials. IMPLICATIONS: The efficacy of alpha-tocopherol alone and in combination with other chemopreventive agents for carcinogenesis in the upper aerodigestive tract should be explored in future trials.

Efficient Use of Historical Data for Genomic Selection: A Case Study of Stem Rust Resistance in Wheat.

Genomic selection (GS) is a methodology that can improve crop breeding efficiency. To implement GS, a training population (TP) with phenotypic and genotypic data is required to train a statistical model used to predict genotyped selection candidates (SCs). A key factor impacting prediction accuracy is the relationship between the TP and the SCs. This study used empirical data for quantitative adult plant resistance to stem rust of wheat (Triticum aestivum L.) to investigate the utility of a historical TP (TPH ) compared with a population-specific TP (TPPS ), the potential for TPH optimization, and the utility of TPH data when close relative data is available for training. We found that, depending on the population size, a TPPS was 1.5 to 4.4 times more accurate than a TPH , and TPH optimization based on the mean of the generalized coefficient of determination or prediction error variance enabled the selection of subsets that led to significantly higher accuracy than randomly selected subsets. Retaining historical data when data on close relatives were available lead to a 11.9% increase in accuracy, at best, and a 12% decrease in accuracy, at worst, depending on the heritability. We conclude that historical data could be used successfully to initiate a GS program, especially if the dataset is very large and of high heritability. Training population optimization would be useful for the identification of TPH subsets to phenotype additional traits. However, after model updating, discarding historical data may be warranted. More studies are needed to determine if these observations represent general trends.

Genetic Gain from Phenotypic and Genomic Selection for Quantitative Resistance to Stem Rust of Wheat.

Stem rust of wheat (Triticum aestivum L.) caused by Puccinia graminis f. sp. tritici Eriks. and E. Henn. is a globally important disease that can cause severe yield loss. Breeding for quantitative stem rust resistance (QSRR) is important for developing cultivars with durable resistance. Genomic selection (GS) could increase rates of genetic gain for quantitative traits, but few experiments comparing GS and phenotypic selection (PS) have been conducted. Our objectives were to (i) compare realized gain from GS based on markers only with that of PS for QSRR in spring wheat using equal selection intensities; (ii) determine if gains agree with theoretical expectations; and (iii) compare the impact of GS and PS on inbreeding, genetic variance, and correlated response for pseudo-black chaff (PBC), a correlated trait. Over 2 yr, two cycles of GS were performed in parallel with one cycle of PS, with each method replicated twice. For GS, markers were generated using genotyping-by-sequencing, the prediction model was initially trained using historical data, and the model was updated before the second GS cycle. Overall, GS and PS led to a 31 ± 11 and 42 ± 12% increase in QSRR and a 138 ± 22 and 180 ± 70% increase in PBC, respectively. Genetic gains were not significant but were in agreement with expectations. Per year, gains from GS and PS were equal, but GS led to significantly lower genetic variance. This shows that while GS and PS can lead to equal rates of short-term gains, GS can reduce genetic variance more rapidly. Further work to develop efficient GS implementation strategies in spring wheat is warranted.

St Louis encephalitis. Quantitative histologic and immunofluorescent studies.

Using techniques of stereology, we measured the severity of lesions in ten cases of acute St Louis encephalitis (SLE) from the 1975 epidemic in northern Illinois. Percentage of fractional volume and numerical profile density on area (N/A) of cellular nodules and N/A of blood vessels with perivascular inflammatory cellular infiltration were significantly correlated in 17 anatomic regions of the CNS. Ranking of the severity of lesions in these regions agreed with subjective estimates of other cases of SLE. Immunofluorescent tests established the presence of SLE viral antigen in cell bodies of neurons. Our findings contribute to better understanding of the pathology of SLE in man.

Epizootic vesicular stomatitis in Colorado, 1982: infection in occupational risk groups.

In 1982-1983, an epizootic of vesicular stomatitis occurred in the western United States. Veterinarians, research workers, and regulatory personnel who were exposed to vesicular stomatitis virus were examined for patterns of human infection and prevalence of vesicular stomatitis New Jersey serotype neutralizing antibody. Insight into the mechanism of transmission was sought by comparing activities of antibody-positive and antibody-negative persons. A statistically significant risk factor was a history of infected animals sneezing in the face of serosurvey participants. Elevated odds ratios were also calculated for those who usually examined the oral cavity of affected animals, had open wounds on hands or arms, and had exposure to saliva through the eye or skin. Relatively intimate direct contact was required; a higher risk was associated with examining horses than cattle. Neutralizing antibody prevalence was significantly higher among exposed persons with illness (23%) than in exposed persons without a history of clinical illness (7%). Overall, however, infectivity of VSNJ for humans during the epizootic was low.

Serological evidence of Hantaan virus infection in the United States.

We found low titers of fluorescent antibodies against Hantaan virus, the etiologic agent of Korean hemorrhagic fever, in sera from 7 of 1,035 patients with febrile illnesses of unknown origin and from 6 of 664 blood donors in the United States. All but 1 of these individuals possessed neutralizing antibodies against Hantaan virus. This was a 31-year-old research technician who had worked with laboratory rodents with virus-induced tumors, but had not traveled abroad, suggesting that infection with Hantaan virus or a closely related agent was locally acquired. However, the precise source of his infection remains unclear.

Lung injury induced by trichloroethylene.

Trichloroethylene (TCE) produced bronchiolar damage when administered to mice. Administration of 2000 mg/kg caused injury in Clara cells of the bronchiolar epithelium, which was observed at 24 h following TCE treatment; increase of the dosage to 2500 mg/kg induced additionally, alterations in alveolar Type II cells of the parenchyma. Specifically, lamellar bodies were reduced in number and microvilli displayed distorted protrusions. The increase in severity of cellular injury with higher dosages of TCE coincided with increased accumulation of pulmonary calcium and lengthened anesthesia recovery times following TCE-induced anesthesia. Time-course studies conducted with 2000 mg/kg demonstrated rapid and marked reduction in pulmonary microsomal cytochrome P-450 content and aryl hydrocarbon hydroxylase activity. Significant decreases were observed as early as 1 h, and the levels were still depressed at 24 h following TCE treatment. Hepatic necrosis was relatively mild at the dosages of TCE examined. These results demonstrate that TCE is pneumotoxic and affects Clara and alveolar Type II cells.

Prevention and treatment of oral complications in the cancer patient.

The mouth and throat are vulnerable sites in cancer patients, subject to treatment-related stomatitis and mucositis, and infection due to bacteria, viruses, and fungi. The author presents a summary of the conditions and their causes, and an update on current treatments of choice.

The effects of running stress on plasma vitamin A levels in rats.

The plasma concentrations of vitamin A, zinc and proteins and the hepatic level of vitamin A were determined in rats subjected to running as a model for stress and which were receiving standard or vitamin-A free diets. All rats showed a decrease in plasma vitamin A with running compared with non-running control animals. Hepatic levels of vitamin A were higher in these two test groups than in their weight- and age-matched non-running controls. The data support that running, like other forms of stress, decreases plasma vitamin A, consistent with the retention of vitamin A in the liver.

Sensitivity of mycoplasmas of the respiratory tract of pigs and horses to erythromycin and its use in selective media.

The ability of erythromycin in liquid medium to suppress the growth of eight species of acholeplasma and of 13 species of mycoplasma was tested. The Acholeplasma spp and two glycolytic Mycoplasma spp from horses--a slow glucose-metabolising (SGM) mycoplasma and a strain N3, related to M mycoides--were sensitive to erythromycin. Thus the growth of acholeplasmas can be suppressed when attempts are made to isolate pathogens from the porcine respiratory tract, but, in the case of horses, erythromycin would suppress not only Acholeplasma spp but also two Mycoplasma spp of unknown pathogenicity in the equine respiratory tract.

The child protective service worker: a profile of needs, attitudes, and utilization of professional resources.

County child protection units throughout the United States were surveyed to (1) profile the attributes of child protection workers, (2) determine their prevailing attitudes and needs, and (3) assess their access to and utilization of professional literature and consultation resources. Responses were received from 301 child protection workers employed in 33 different states. Respondents were generally depressed about their working conditions, the burden of huge caseloads, and unrealistic expectations of them. Job dissatisfaction was especially prevalent among workers who had been in the field for longer periods of time. Many workers had developed attitudes of resignation to their inability to help clients and had a tendency to avoid client contact. Workers reported doing very little professional reading due to the service requirements of their large caseloads and inaccessibility to journals and other meaningful literature pertinent to the field of child abuse and neglect. The availability of consultation in major specialty areas related to the performance of their child protective duties was frequently inadequate to meet their needs. Participation in formal training prior to first case involvement promoted professional reading and worker confidence in the quality of service provided. Worker job satisfaction and self-perceived professional skills were enhanced by membership in professional associations or societies and membership in or use of multidisciplinary teams. These results suggest the need to further develop national and regional resource centers in support of the practice of child protective service (CPS) workers.

A new microcomputer-controlled neutron activation and analysis system. Description and applications for the analysis of bioenvironmental specimens.

A microcomputer-controlled irradiation and measurement system and a microprocessor-controlled sample changer have been installed at the SLOWPOKE-2 Facility at the Royal Military College of Canada (RMC). These systems can provide the gamut of instrumental neutron activation analysis (INAA) techniques for the analyst. Custom software has been created for system control, data acquisition, and off-line spectral analysis using programs that incorporate Gaussian peak-fitting methods of analysis. The design and use of the equipment is discussed, and the performance is illustrated with results obtained from the analysis of marine sediment and biological reference materials.