Post-cutting quality changes of fresh-cut artichokes treated with different anti-browning agents as evaluated by image analysis

Fresh-cut processing can add convenience to artichoke consumption, although post-cutting browning is still a major problem. Different compounds (ascorbic acid, citric acid, cysteine, and their combination, ethanol, sodium chloride, 4-hexylresorcinol) were tested at different concentrations in two experiments. An algorithm for rapid colour measurements by means of image analysis was implemented, and allowed measurement of L*, a*, and b* values from the whole quarter surface and from the browned areas, while the external appearance of artichoke quarters was evaluated using an anchored subjective scale. Cysteine (0.5%) was the most effective treatment to prevent browning as evaluated by colour attributes and appearance score. Its effectiveness was improved by increasing the pH of the solution from the natural pH (2.1) to pH 3, resulting in L* values of browned areas about 30% higher than controls (27.4 and 21.5 respectively). The mean values of appearance scores for cysteine treated samples were all above the limit of marketability (score 3), significantly higher than in control samples which had mean values below this limit. All colour parameters were significantly correlated with appearance scores, and L* of the whole quarter surface had the highest correlation. The results represent a step forward in research on anti-browning treatments for fresh-cut artichokes, also providing an objective tool for colour evaluation.     

ABOVE- AND BELOW-GROUND NUTRIENT TISSUE CONCENTRATION AND LEAF PIGMENT CHANGES IN PATAGONIAN WOODY SEEDLINGS GROWN UNDER LIGHT AND SOIL MOISTURE GRADIENTS

To understand the ecophysiology of natural regeneration above- and below-ground nutrient tissue concentration and leaf pigment changes in Nothofagus pumilio (lenga) seedlings grown in three light intensities (4%, 26% and 64% of natural irradiance) and two soil moisture levels (40–60% and 80–100% soil capacity) under greenhouse controlled conditions were evaluated. Carbon (C), nitrogen (N), phosphorus (P), magnesium (Mg), potassium (K), calcium (Ca) and pigment (chlorophylls and carotenoids) were measured on seedlings. Carbon, N, Mg, K and Ca increased in low light intensity and soil moisture treatments, while P decreased. Nutrients were higher in above- than in below-ground biomass. Chlorophylls were lower in high light treatments, while carotenoids increased their content. All pigments were greater in low soil moisture treatments. These changes are closely related to their photosynthetic plasticity and biomass compartmentalization. Plants growing in high light were more efficient to produce the same amount of plant biomass.     

Three groups of Babesia canis distinguished and a proposal for nomenclature

Summary

Two stocks of large Babesiae from dogs originating in France, transmitted by Dermacentor reticulatus, two from North Africa, having Rhipicephalus sanguineus as vector, and one from South Africa, transmitted by Haemaphysalis leachi, were compared in cross‐immunity tests in dogs and in the indirect fluorescent antibody test (IFAT).

The French and North African stocks did not immunise against the South African one, while the North African stocks did not protect against a French one. The South African stock partially protected against a French one.

The three groups could be clearly distinguished in the IFAT These differences have practical implications for existing and future vaccines against canine babesiosis and for the serological diagnosis of atypical and chronic cases.

It is proposed to use a trinomial system of nomenclature for these groups: Babesia canis canis (Piana and Galli‐Valerio, 1895), Babesia canis vogeli Reichenow, 1937, and Babesia canis rossi (Nuttall, 1910), having Dermacentor, Rhipicephalus and Haemaphysalis ticks as their vectors respectively.     

The indirect fluorescent antibody test for bovine anaplasmosis

Summary

An indirect fluorescent antibody test was used succesfully for the serodiagnosis of experimental Anaplasma infections in cattle. Specific antibodies were detected three to ten days after anaplasma bodies werd found in the blood, and persistedat least 15 weeks post‐infection.

An American and an African stock of A. marginale were used to prepare antigens, and gave comparable results when tested on sera positive to either of these stocks, as well as to an A. centrale‐like stock from Korea.

There were no cross‐reactions with several Theileria, Babesia, Trypanosoma and Eperythrozoon species.     

Allometric relations for biomass partitioning of Nothofagus antarctica trees of different crown classes over a site quality gradient

Data on tree biomass are essential for understanding the forest carbon cycle and plant adaptations to the environment. We determined biomass accumulation and allometric relationships in the partitioning of biomass between aboveground woody biomass, leaves and roots in Nothofagus antarctica. We measured above- and belowground biomass of N. antarctica trees across different ages (5–220 years) and crown classes (dominant, codominant, intermediate and suppressed) in three site qualities. The biomass allocation patterns were studied by fitting allometric functions in biomass partitioning between leaves (M_L), stem and branches (M_S) and roots (M_R). These patterns were tested for all pooled data and according to site quality and crown classes. Biomass accumulation varied with crown class and site quality. The root component represented 26–72% of the total biomass depending on age and site. N. antarctica scaling exponents for the relationships M_Lvs. M_S, M_Avs. M_R, and M_Svs. M_R were close to those predicted by the allometric biomass partitioning model. However, when biomass allocation was analyzed by site quality the scaling exponents varied following the optimal partitioning theory which states that plants should allocate more biomass to the part of the plant that acquires the most limiting resource. In contrast, the crown class effect on biomass partitioning was almost negligible. In conclusion, to obtain accurate estimations of biomass in N. antarctica trees the allometric approach appears as an useful tool but the site quality should be taken into consideration.     

Transfer of Cd, Pb, Ra and U from Phosphogypsum Amended Soils to Tomato Plants

About 170 million tons of phosphogypsum (PG) are annually generated worldwide as a by-product of phosphoric acid factories. Agricultural uses of PG could become the main sink for this waste, which usually contains significant radionuclide (from the ²³⁸U-series) and toxic metals concentrations. To study PG effects on pollutant uptake by crops, a completely randomised greenhouse experiment was carried out growing Lycopersicum esculentum Mill L. on a reclaimed marsh soil amended with three PG rates (treatments), corresponding to zero (control without PG application), one, three and ten times the typical PG rates used in SW Spain (20 Mg ha^?1). The concentrations of Cd, Pb, U (by inductively coupled plasma mass spectroscopy) and ²²⁶Ra and ²¹⁰Po (by γ-spectrometry and α-counting, respectively) were determined in soil, vegetal tissue and draining water. Cadmium concentrations in fruit increased with PG rates, reaching 44?±?7 μg kg^?1 formula weight with ten PG rates (being 50 μg kg^?1 the maximum allowed concentration by EC 1881/2006 regulation). Cd transfer factors in non-edible parts were as high as 4.8?±?0.5 (dry weight (d.w.)), two orders of magnitude higher than values found for lead, lead, uranium and radium concentrations in fruit remained below the corresponding detection limits—0.5 and 0.25 mg kg^?1 and 0.6 mBq kg^?1, respectively (in a d.w. basis). ²³⁸U (up to 7 μg kg^?1 d.w.) and ²¹⁰Po (up to 0.74 Bq kg^?1 d.w.) could be measured in some fruit samples by α-spectrometry. Overall, the concentrations of these metals and radionuclides in the draining water accounted for less than 1% of the amount applied with PG.     

An invasive insect herbivore disrupts plant volatile-mediated tritrophic signalling

Plants respond to insect attack by emission of volatile organic compounds, which recruit natural enemies of the attacking herbivore, constituting an indirect plant defence strategy. In this context, the egg parasitoid Trissolcus basalis is attracted by oviposition-induced plant volatiles emitted by Vicia faba plants as a consequence of feeding and oviposition by the pentatomid host Nezara viridula. However, this local tritrophic web could be affected by the recent invasion by the alien pentatomid bug Halyomorpha halys, an herbivore that shares the same environments as native pentatomid pests. Therefore, we investigated in laboratory conditions the possible impact of H. halys on the plant volatile-mediated signalling in the local tritrophic web V. faba–N. viridula–T. basalis. We found that T. basalis wasps were not attracted by volatiles induced in the plants by feeding and oviposition activities of H. halys, indicating specificity in the wasps’ response. However, the parasitoid attraction towards plant volatiles emitted as a consequence of feeding and oviposition by the associated host was disrupted when host, N. viridula, and non-associated host, H. halys, were concurrently present on the same plant, indicating that invasion by the alien herbivore interferes with established semiochemical webs. These outcomes are discussed in a context of multiple herbivory by evaluating the possible influences of alien insects on local parasitoid foraging behaviour.     

Theileria orientalis, a cosmopolitan blood parasite of cattle: demonstration of the schizont stage

Serological and morphological comparison of Theileria orientalis stocks from Australia, Britain, Iran, Japan and the USA with a more pathogenic stock from Korea, corresponding to T sergenti of Russian literature, showed that they all belong to one species, for which the name T orientalis is recommended. T orientalis is now known to occur on all continents. Macroschizonts and microschizonts, found in some of the calves infected with the Korean stock, are described and illustrated. Infections with the Korean stock were associated with early hyperthermia during the period schizonts are found, and commonly with high parasitaemias and anaemia even in unsplenectomised calves. The higher pathogenicity of this stock may be related to a faster rate of division. T orientalis may cause latent infection in sheep. With the exception of the stock from the USA, all stocks could be transstadially transmitted by Haemaphysalis longicornis and, or, H punctata.