Production of hydrophilic phytotoxins by <Emphasis Type="Italic">Mycosphaerella fijiensis</Emphasis>

We have established a reproducible strategy to purify hydrophilic phytotoxins present in the aqueous filtrate of Mycosphaerella fijiensis Morelet. The lyophilized culture filtrate is initially treated with activated charcoal, then successively purified using vacuum liquid chromatography and semipreparative high performance liquid chromatography. Phytotoxic activity was tested using a leaf-spot assay on healthy banana leaves. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Occurrence of Cucurbit Yellow Stunting Disorder Virus (CYSDV) and Beet Pseudo-yellows Virus in Cucurbit Crops in Spain and Transmission of CYSDV by Two Biotypes of Bemisia tabaci

The relative occurrence in Spain of two whitefly transmitted closteroviruses causing similar yellowing diseases in melon and cucumber greenhouse crops was studied. Based on a RT-PCR assay, a 1994–1997 survey of Spanish greenhouses showed that the recently described Bemisia tabaci-transmitted cucurbit yellow stunting disorder virus (CYSDV) has displaced the Trialeurodes vaporariorum-transmitted beet pseudo-yellows virus (BPYV), a virus that was present in the area since the late 1970s. The CYSDV transmission rates by each of the two biotypes of B. tabaci present in Spain were compared. The results showed that the ubiquitous B biotype and the resident Q biotype (found in Spain and Portugal) were able to transmit CYSDV with similar efficiency.     

Evaluation of whitefly-mediated inoculation techniques to screen Lycopersicon esculentum and wild relatives for resistance to Tomato yellow leaf curl virus

For two consecutive years nine hybrids and three varieties of tomato, four Lycopersicon peruvianum and four Lycopersicon chilense accessions were screened for Tomato yellow leaf curl virus (TYLCV) resistance. Three inoculation techniques using Bemisia tabaci, the vector of TYLCV, were compared: (1) artificial mass inoculation-simultaneous infection of cultivated and wild material in greenhouses; (2) artificial cage inoculation-individual infection in insect-proof cages; (3) natural field infection. Artificial inoculations led to higher levels of infection, but different patterns of response to each inoculation technique were found depending on the resistance level. Tomato varieties showed an important fruit set reduction after both artificial and natural inoculations. In contrast, field infection was milder in tomato hybrids, in which yield was barely affected. These hybrids showed a wide range of reactions with the two artificial inoculation techniques, but infection was always more severe after mass inoculation. Extreme severity of mass infection made it difficult to differentiate among variable degrees of resistance that were more reliably detected with cage inoculation. The hybrids F3524, F3522, Fiona, and Tyking showed the highest level of resistance. F3524 and F3522 had an acceptable yield in field and cage assays, but their resistance collapsed under massive conditions of infection. Tyking and Fiona exhibited the best response in all conditions, although their yield was moderately reduced in mass assays. Mass inoculation was not adequate for the screening of wild Lycopersicon. Some susceptible plants escaped infection, probably as a consequence of non-preference mechanisms and loss of vector infectivity. Individual inoculation in cages prevented the risk of non-infection, ensuring 100% disease incidence. This technique allowed the selection of highly resistant wild sources. L. chilense LA 1969 and LA 1963 had the highest level of resistance with the three inoculation techniques. L. peruvianum PI-126944 and L. chilense LA 1932, which were only tested in mass and field conditions, also exhibited a promising response. The results proved that the inoculation technique influences the response of tomato and wild Lycopersicon spp to TYLCV. It is concluded that artificial cage inoculation, although more time-consuming, is the most efficient, adequate, and reliable technique to screen both cultivated and wild Lycopersicon species for resistance to TYLCV. This revised version was published online in July 2006 with corrections to the Cover Date.     

New sources for high resistance of tomato to the tomato spotted wilt virus from Lycopersicon peruvianum

Mechanical inoculation and transmission by thrips in a growth chamber were used in order to screen Lycopersicon peruvianumand Lycopersicon chilense germplasm for tomato spotted wilt virus (TSWV) resistance. Two highly aggressive Spanish TSWV isolates (HA-931100 and T-941117), having different restrictotypes were used. L. peruvianum accessions PI-126935, PI-126944, CIAPAN 16, PE-18 and CIAPAN 17 showed high resistance to both isolates in mechanical and thrips transmission. Their resistance appears useful in breeding programmes.     

Use of the 1H nuclear magnetic resonance spectra signals from polyphenols and acids for chemometric characterization of cider apple juices

The low field region (5.8-9.0 ppm) corresponding to aromatic protons and the region 1.8-3.0 ppm of the (1)H NMR spectra were used for characterization and chemometric differentiation of 52 apple juices obtained from six cider apple varieties. The data set consisted of 14 integrated areas corresponding to resonances from acids and phenolic compounds. Multivariate procedures based on hierarchical cluster and discriminant analysis were performed on selected signals of the spectra to determine whether it was possible to distinguish the different juices. Cluster analysis was able to satisfactorily classify the six apple varieties. Discriminant analysis, by means of stepwise procedure for variables selection and leave-one-out for cross-validation, was applied to 40 samples from the year 2001, obtaining recognition and prediction abilities of 100%. The most discriminant variables corresponded to poliphenols, (-)-epicatechin, phloridzin-phloretin, and p-coumaric, chlorogenic, and malic acids. The classification model was applied to 12 samples from apples harvested in the years 2002 and 2003, and the prediction ability was 91.7%.     

Reproductive phenology of Creole horses in Ecuador in the absence of photoperiod variation: The effects of forage availability and flooding affecting body condition of mares

Horse reproduction tends to be seasonal. The main adjusting factor in their original temperate ranges is photoperiod variation, although it is absent in equatorial areas where horses were introduced by European colonizers. Hence, dates of reproduction in these areas may be influenced by factors affecting mares’ conditions and the success of foaling. Here we study reproductive timing in Creole horses in Ecuador reared in an extensive production system. We found that foaling peaked in August. Mares’ conditions showed one peak in June‐July, before the start of the breeding season, and another in December, and it was highly variable along the year. Mares’ conditions increased after a period of vegetation growth and thus appeared negatively associated with the increment of grass greenness (normalized difference vegetation index data). Seasonal flooding of some pasturelands during March and April appeared to seriously impair mares’ conditions and probably influenced the timing of foaling toward the dry season. Our results evidenced that horse breeding in these equatorial areas tended to be seasonal and point to some key factors that influence phenology by affecting body condition of mares, which may have implications for horse biology and management.     

Carbon sequestration in a limestone quarry mine soil amended with sewage sludge

To reclaim a limestone quarry, 200 and 400 Mg/ha of municipal sewage sludge were mixed with an infertile calcareous substrate and spread as mine soil in 1992. Soil samples were taken 1 week later and again after 17 yr of mine soil rehabilitation so as to assess changes in the amount and persistence of soil organic carbon (SOC). Sludge application increased SOC as a function of the sludge rate at both sampling times. Seventeen years after the sludge amendments, the nonhydrolysable carbon was increased in the 400 Mg/ha of sludge treatment. The recalcitrance of SOC was less in sludge‐amended soils than in the control treatment at the initial sampling, but 17 yr later this trend had reversed, showing qualitative changes in soil organic carbon. The CO₂‐C production had not differed between treatments, yet the percentage of mineralized SOC was less in the high sludge dose. When the size of active (C_active) and slow (C_slow) potentially mineralizable C pools was calculated by curve fitting of a double‐exponential equation, the proportion of C_active was observed to be smaller in the 400 Mg/ha sludge treatment. Soil aggregate stability, represented by the mean weight diameter of water‐stable soil aggregates, was significantly greater in mine soil treated with the high dose of sludge (18.5%) and SOC tended to be concentrated in macro‐aggregates (5–2 mm). Results suggest that SOC content in sludge‐amended plots was preserved due by (i) replacement of the labile organic carbon of sludge by more stable compounds and (ii) protection of SOC in aggregates.     

Computed tomography is a feasible method for quantifying bone density in Macaca mulatta

Osteopathologies are a result of advanced age and decreased bone density and represent a global health problem. It is therefore important to generate models for longitudinal studies of the pathophysiology in order to improve early diagnosis and develop preventive therapies. For this kind of research, the use of computed tomography (CT) to evaluate bone health offers advantages over other techniques since it provides more complete information. The aim of this prospective, pilot study was to obtain measurements of the left femur from a population in captivity of 32 rhesus monkeys (Macaca mulatta) in order to standardize the model for future research. Healthy subjects from 5 to 28 years old were chosen. Three groups with different ages were formed as follows: (1) 5–9 years, (2) 10–19 years, and (3) 20–28 years. Semi‐automatic segmentation by threshold defined the regions of interest, which were subdivided in the range of 300–700 Hounsfield units (HU) for trabecular bone and >700 HU for cortical bone. Then, the proportional ratios of the volumes of trabecular bone and cortical bone were obtained. Significant differences (analysis of variance test) in the averages of Hounsfield units, cortical, and trabecular bone proportions from each age group proved that a decrease in bone density begins at approximately 20 years of age. The values presented here, as well as the method to obtain them from CT scans, can be used as a baseline in a primate model for long‐term research in bone pathology diagnosis and treatment.     

Chemical components with health implications in wild and cultivated Mexican common bean seeds (Phaseolus vulgaris L.)

Common bean effects on health have been related to its dietary fiber content and other active compounds. This study assessed the content of flavonoids, coumestrol, phenolic acids, galactooligosaccharides, and phytic acid in wild and cultivated Mexican common bean seeds (raw and cooked) and that of flavonoids, coumestrol, and phenolic acids in germinated bean seeds. The presence of isoflavones in raw bean seeds was not confirmed by the UV spectra. Quercetin, kaempferol, p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, and vanillic acid mean contents were 10.9, 52.3, 10.1, 9.6, 5.4, and 18.2 microg/g, respectively; raffinose, stachyose, verbascose, and phytic acid mean contents were 8.5, 56.3, 5.5, and 11.5 mg/g, respectively, in raw seeds. All compounds were affected by autoclaving, and germination resulted in a de novo synthesis of flavonols, phytoestrogens, and phenolic acids. The impact on health of common bean seed is affected by dietary burden, specific compounds content, and processing. On the other hand, germinated bean seed or beans sprouts may be sources of antioxidants and phytoestrogens.     

Isolation of antioxidant compounds from orange juice by using countercurrent supercritical fluid extraction (CC-SFE).

Antioxidants from orange juice are isolated by the use of countercurrent supercritical fluid extraction (CC-SFE) and characterized by reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) and diode-array detection (DAD). A pilot-scale SFE plant equipped with a packed column has been employed for countercurrent extraction and fractionation of raw orange juice with carbon dioxide. Several experiments have been performed in order to study the effect of the countercurrent conditions on the content of antioxidative compounds. In this study, the main variable that has been considered is the solvent-to-feed ratio (S/F) because it plays an essential role in the extraction efficiency. The values tested covered a wide range of sample and solvent (CO(2)) flow rates. In each experimental run, two different extracted fractions and the residual nonextracted juice were obtained and characterized. Different flavonoids have been identified in the fractions obtained after CC-SFE. The possibility of using this process for antioxidant compounds enrichment is discussed.