Ammonia removal in selected aquaculture water reuse biofilters

Four fixed-film biological filters (rotating biological contactor, biodrum, trickling filter, and a submerged anaerobic filter) were tested for the removal of ammonia using a simulated warmwater fish and invertebrate culture water supply. Filter design may be determined based on the results of ammonia removal efficiency over a wide range of hydraulic loads. The rotating biological contactor (RBC) provided the best ammonia removal (over 90%) up to about 0·06 m³ m^?2 day^?1 (1·2 gpd ft^?2). The biodrum removed over 80% of the ammonia to a hydraulic load of 0·05 m³ m^?2 day^?1 (0·9 gpd ft^?2). The trickling filter removed 50% of the ammonia at a hydraulic loading of 0·012 m³ m^?2 day^?1 (0·3 gpd ft^?2).     

Combination active optical and passive thermal infrared sensor for low-level airborne crop sensing

An integrated active optical, and passive thermal infrared sensing system was deployed on a low-level aircraft (50 m AGL) to record and map the simple ratio (SR) index and canopy temperature of a 230 ha cotton field. The SR map was found to closely resemble that created by a RapidEye satellite image, and the canopy temperature map yielded values consistent with on-ground measurements. The fact that both the SR and temperature measurements were spatially coincident facilitated the rapid and convenient generation of a direct correlation plot between the two parameters. The scatterplot exhibited the typical reflectance index-temperature profile generated by previous workers using complex analytical techniques and satellite imagery. This sensor offers a convenient and viable alternative to other forms of optical and thermal remote sensing for those interested in plant and soil moisture investigations using the ‘reflectance index-temperature’ space concept.     

Gas sensor array for blueberry fruit disease detection and classification

A conducting polymer gas sensor array (electronic nose) was evaluated for detecting and classifying three common postharvest diseases of blueberry fruit: gray mold caused by Botrytis cinerea, anthracnose caused by Colletotrichum gloeosporioides, and Alternaria rot caused by Alternaria sp. Samples of ripe rabbiteye blueberries (Vaccinium virgatum cv. Brightwell) were inoculated individually with one of the three pathogens or left non-inoculated, and volatiles emanating from the fruit were assessed using the gas sensor array 6–10 d after inoculation in two separate experiments. Principal component analysis of volatile profiles revealed four distinct groups corresponding to the four inoculation treatments. MANOVA, conducted on profiles from individual assessment days or from combined data, confirmed that the four treatments were significantly different (P < 0.0001). A hierarchical cluster analysis indicated two super-clusters, i.e., control cluster (non-inoculated fruit) vs. pathogen cluster (inoculated fruit). Within the pathogen cluster, fruit infected by B. cinerea and Alternaria sp. were more similar to each other than to fruit infected by C. gloeosporioides. A linear Bayesian classifier achieved 90% overall correct classification for data from experiment 1. Tenax? trapping of volatiles with short-path thermal desorption and quantification by gas chromatography–mass spectrometry was used to characterize volatile compounds emanated from the four groups of berries. Six compounds [styrene, 1-methyl-2-(1-methylethyl) benzene, eucalyptol, undecane, 5-methyl-2-(1-methylethyl)-2-cyclohexen-1-one, and thujopsene] were identified as contributing most in distinguishing differences in the volatiles emanating from the fruit due to infection. A canonical discriminant analysis model using the relative concentration of each of these compounds was developed and successfully classified the four categories of berries. This study underscores the potential feasibility of using a gas sensor array for blueberry postharvest quality assessment and fungal disease detection.     

Development and validation of a soil-based geographic information system model of habitat of Fossaria bulimoides, a snail intermediate host of Fasciola hepatica

Soil maps were investigated for their potential to indicate the spatial distribution of habitat of the amphibious snail, Fossaria bulimoides, the intermediate host of Fasciola hepatica in Louisiana. On a 760 ha farm adjacent to the Gulf of Mexico, most snail habitats clustered along interfaces of cheniers (relict beaches with sandy soils) with marsh (heavy, gleyed clays). A few small foci occurred on the cheniers above interfaces. Virtually no habitats occupied marsh away from these interfaces, on this or several other farms previously examined. Habitat and soil map overlays were analyzed in a raster-based geographic information system (GIS) with a 10 m pixel size; a model of habitat was generated as bands 50–90 m wide at chenier-marsh interfaces. The model was extrapolated to a 29 000 ha study area and tested on 12 additional farms not adjacent to the Gulf. On these farms, snail surveys were carried out as transects on three strata: waveface (WF, former beachfront) and backslope (BS) chenier-marsh interfaces, and chenier. The perimeters of all habitats encountered were outlined. The interface of marsh with chenier backslopes occupied 5.25% of the area of the farms, but held 21.69% of snail habitat area. Additionally, chenier soils of the Hackberry-Mermentau complex (HM) occupied 12.32% of farm area, but held 61.39% of habitat. Habitat area was related by regression analysis to the proportion of farm consisting of HM soils (r² = 0.41, P < 0.05).     

Development and evaluation of a rapid absorbed enzyme immunoassay test for the diagnosis of Johne''s disease in cattle

An absorbed enzyme immunoassay (EIA) test for Johne's disease in cattle was developed in which absorption of cross-reacting antibodies occurred as a rapid reaction in solution rather than overnight with whole organisms and a subsequent centrifugation step. Total test time was reduced to less than 2 h with a minimum of manipulations. The test was evaluated in cattle herds from Johne's disease-endemic and Johne's disease-free regions of Australia. Specificity was 99.8%. Calculations of sensitivity were affected by the history of the herd under test. However, the EIA detected in excess of 80% of animals before onset of clinical disease and 65% of faecal shedders were EIA positive on, or before, first detection of Mycobacterium paratuberculosis in their faeces. The test should aid epidemiological studies and be a useful tool in the management and control of Johne's disease.     

The prevalence of itchmite, Psorergates ovis, among sheep flocks with a history of fleece derangement

An investigation of sheep flocks in the main sheep raising areas of New South Wales showed that the itchmite Psorergates ovis was frequently associated with fleece derangement. In 26 of the 41 flocks examined, P. ovis was the only ectoparasite detected. P. ovis and the sheep body louse Damalinia ovis, were found in 5 flocks. No external parasites were found on sheep examined from the 10 remaining flocks. The type of fleece derangement most frequently recorded was rubbing which in some cases was combined with areas of chewed fleece. Among flocks, there were positive relations between the prevalence of fleece derangement and prevalence of itchmite or scurf and between itchmite count and mean scurf score. Within flocks, itchmite infested sheep or sheep with scurf had higher prevalences of fleece derangement than sheep on which no mites or no scurf were found. Itchmite infested sheep had a higher prevalence of scurf than those with no detectable mite infestation. There were no significant differences in itchmite populations or fleece derangement between untreated flocks and flocks treated with synthetic pyrethroids, organophosphates or arsenic and rotenone.     

Monitoring Mycoplasma gallisepticum and Mycoplasma synoviae infection in breeder chickens after treatment with enrofloxacin.

Three experimental strains of breeder chickens were accidentally exposed to Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS), presumably from a newly introduced group of leghorn-type pullets. The experimental strains subsequently became infected and were diagnosed positive for MG and MS by the serum plate agglutination (SPA) test and confirmed by the hemagglutination inhibition (HI) test and the polymerase chain reaction (PCR) of tracheal swabs. Treatment with 10 mg/kg enrofloxacin via drinking water for 14 days was elected. Before and after initiation of treatment, MG and MS were monitored for changes by SPA, HI, PCR, and culture, with sampling intervals ranging from 1 wk to 7 wk. MG and MS SPA, HI, PCR, and culture were performed at each sampling period, with the exception of weeks 1.0 and 6.5. Week 1.0 included SPA and His for MG and MS. Week 6.5 included PCR and culture for MG and MS. The MG and MS SPA results were positive throughout the 29-wk trial period. MG HI titers declined until the last sampling, whereas the MS HI titers did not decline significantly. PCR for MG yielded only one positive result, which occurred before treatment. MS PCR remained positive throughout the trial period. MG was never isolated from any sample; however, one MS organism was isolated during treatment. The treatment regimen was effective for MG on the basis of PCR results. Treatment with enrofloxacin did not eliminate SPA reactions during the 29-wk trial period. MG HI titers remained in the suspicious range throughout the remainder of the trial period. Four weeks after the treatment ended, MG HIs were reduced by approximately 40%, with MS HIs remaining high throughout the 29-wk period. PCR appeared to be a sensitive and specific test on the basis of correlation with HIs. On the basis of the isolation of MS during treatment and continued subsequent PCR positive reactions, the treatment for MS with enrofloxacin was not as efficacious as for MG.     

Variation for agronomic and processing traits in Solanum tuberosum haploids × wild species hybrids

Summary The broad range of wild and cultivated species relatives of the commerical potato (Solanum tuberosum L.), guarantees the existence of a gene reservoir to be screened for traits that are absent or present only in low frequencies in the cultivated germplasm. Haploids (2n=2x=24) extracted from the cultivated tetraploid (2n=4x=48) germplasm cross easily with diploid (2n=2x=24) potato species and produce fertile progeny. As most haploid × species hybrids tuberize under long day conditions they can be maintained clonally and evaluated for the traits of interest. Three populations involving Tuberosum haploids × Solanum bukasovii (tub x buk), Tuberosum haploids × Solanum sparsipilum, (tub × spl) and Tuberosum haploids × Solanum berthaultii (tub x ber) clones, were planted at two locations in Wisconsin. The haploids were derived from W231, a selected clone from the University of Wisconsin Potato Breeding Program. The objectives were: to evaluate the H-S populations for agronomic and processing traits, and to determine the phenotypic associations between them. Data were recorded on haulm maturity (HM), tuber weight (TW) and tuber number (NT) per plant, specific gravity (SG), chip color after harvest (CH), and chip color after storage at 4° C and one week of reconditioning at room temperature (CH1). Results for SG and CH indicated good potential of the germplasm evaluated to introgress these traits into the commercial potatoes. For instance, the SG mean for tub x buk, tub x spl and tub x ber were 1.079, 1.086 and 1.082, respectively, and their means for CH were 4.8, 3.9 and 3.5. Chip color after storage and reconditioning was found in low frequency in the populations. Four clones in the tub x spl population, and three clones in the tub x ber population had CH1 4.0, the commercially acceptable score for this trait. Significant (p 0.01) phenotypic correlations (r) were found between HM and SG (r=–0.46 in tub x buk, r=–0.61 in tub x spl, and r=–0.34 in tub x ber), NT and TW (r=0.79 in tub x buk, r=0.88 in tub x spl, and r=0.71 in tub x ber), and TW and SG (r=0.40 in tub x buk, and r=0.36 in tub x spl). The correlation coefficients between processing traits were not significant, which may indicate the presence of separate genetic mechanisms governing the inheritance of these traits.     

Male fertility and cytology of triploid hybrids between tetraploidSolanum commersonii (2n=4x=48, 2EBN) and Phureja-Tuberosum haploid hybrids (2n=2x=24, 2EBN)

Summary Solanum commersonii Dun. is a diploid (2n=2x=24, 1EBN) wild species of potential value for potato breeding. It is a reproductively isolated species and cannot be crossed with Tuberosum haploids (2n=2x=24, 2EBN) or other diploid 2EBNSolanum species. In order to overcome the EBN barriers, triploid hybrids were produced between Phureja-Tuberosum haploid hybrids, which form 2n pollen grains by parallel spindles, and tetraploidS. commersonii. Microsporogenesis analysis of the triploids indicated a trend towards low values of chromosome distribution at Anaphase I; lagging chromosomes were often observed as well. Despite these abnormalities, the percentage of stainable pollen was very high, ranging from 5.0% to 74.3%. A high variation in pollen grain diameter was also evident. Parallel and tripolar orientation of spindles at Metaphase II of microsporogenesis was a common feature of all the triploids analyzed, but dyads and triads were observed at a very low frequency. Therefore, also the frequency of 2n pollen was very low; the different size of stainable pollen appears to represent the ploidy levels which are possible according to the distribution of chromosomes in Anaphase I. The results obtained also suggest thatS. commersonii could have minor genes acting at the end of meiosis in such a way that, despite the presence of parallel/tripolar spindles, dyads/triads are not formed.Contribution no. 124 from the Research Center for Vegetable Breeding.