Stay-green phenotype slows the carotenogenic process in Capsicum annuum (L.) fruits

Stay-green mutants have been very useful for elucidating the chlorophyll catabolism pathway in higher plants. In the present study the possible relationship between the retention/catabolism of chlorophylls and the carotenogenic process taking place in ripening Capsicum annuum (L.) fruits has been investigated. Phytylated, dephytylated and oxidized chlorophyll derivatives, and total and individual carotenoids were analyzed over the whole ripening period. In general terms, the biosynthesis of carotenoid pigments taking place during the ripening of C. annuum fruits is identical in both red and stay-green lines, so that the carotenogenic process is independent of the retention of chlorophylls. However, it has been found that the carotenogenesis is slowed in the stay-green lines. Therefore, although the catabolism of chlorophylls and biosynthesis of carotenoids seem to be separate processes, the fact that they are taking place in the chloroplast/chromoplast suggests that some kind of interaction between the two processes may occur at different levels. Plastids corresponding to the wild genotype (red color fruit phenotype) show high plastoglobuli density and thylakoids are almost absent, whereas in the case of stay-green phenotype, thylakoids and plastoglobuli coexist in the same plastid (chlorochromoplasts). The role of carotenoid pigments on the physiological mechanism for protecting the preserved thylakoid structures is discussed.     

Identification of Ehrlichia ruminantium (Gardel strain) IFN-gamma inducing proteins after vaccination with a killed vaccine

IFN-γ is considered as a key factor in protection against heartwater of ruminants, caused by the obligate intracellular bacterium Ehrlichia ruminantium. In this study, a better definition of the molecular masses of IFN-γ inducing proteins of the Gardel strain of E. ruminantium was obtained by the use of continuous flow electrophoresis (CFE) and sensitized polyclonal lymphocytes. Out of 15 E. ruminantium CFE fractions tested within the 14–39 kDa region, eight were commonly reacted to by all goats. Interestingly, half of these fractions fall within the 23–29 kDa region, shown previously to contain polymorphic B-cell epitopes. Thus, the results suggest that this region also contains T-cell epitopes potentially involved in protection. Also, several proteins were found to be more immunogenic than the serologically immunodominant MAP1 protein. Finally, high activity within the 15–19 kDa region was observed, which confirms previous work done with CD4+ T-cell lines obtained from cattle immunized with a South African strain of E. ruminantium. The proteins falling within the molecular weight ranges defined in this study may have potential as vaccine antigens.     

The effect of biochar with biogas digestate or mineral fertilizer on fertility,aggregation and organic carbon content of a sandy soil: Results of a temperate field experiment

Substitution of mineral fertilizers with organic soil amendments is postulated to improve productivity‐relevant soil properties such as aggregation and organic matter (OM) content. However, there is a lack of studies analyzing the effects of biochar and biogas digestate versus mineral fertilizer on soil aggregation and OM dynamics under temperate field conditions. To address this research gap, a field experiment was sampled four years after establishment on a sandy Cambisol in Germany where mineral fertilizer or liquid biogas digestate was applied with or without 3 or 40 Mg biochar ha^?1 (produced at 650°C). Soil samples were analyzed for soil organic carbon (SOC) content, pH, cation exchange capacity, bulk density, water‐holding capacity, microbial biomass, aggregate size class distribution, and the SOC content associated with these size classes. 40 Mg biochar ha^?1 significantly increased SOC content in all fractions, especially free particulate OM and the 2–0.25 mm fraction. The yield of small macroaggregates (2–0.25 mm) was increased by biochar, but cation exchange capacity, water‐holding capacity, and pH were not consistently improved. Thus, high‐temperature biochar applied to a sandy soil under temperate conditions is primarily recommended to increase SOC content, which could contribute to climate change mitigation if this C remains sequestered over the long‐term. Fertilizer type did not significantly affect SOC content or other measured properties of the sandy Cambisol, suggesting that replacement of mineral fertilizer with digestate has a neutral effect on soil fertility. Co‐application of biochar with digestate provided no advantages for soil properties compared to co‐application with mineral fertilizer. Thus, independent utilization of these organic amendments is equally suitable.     

Field performance characterization of strawberry (Fragaria × ananassa Duch.) plants derived from cryopreserved apices

This study compares agronomic traits of two cultivars of strawberry in plants derived from conventional propagation, micropropagation and cryopreserved apices. The agronomic traits evaluated were fruit production and fruit quality. Differences were found in some of the fruit production traits studied in the plants post-micropropagation and post-cryopreservation when compared to conventionally propagated plants of the cultivar ‘Andana’; showing the first two groups higher second class yield and smaller fruits. Plants of the cultivar ‘Camarosa’ post-cryopreservation showed differences in traits related to fruit quality when compared to the other two groups of plants (internal colour, firmness and soluble solids). No adverse effect on agronomic traits could be associated with the use of cryopreservation. Plants from in vitro and cryopreservation origin were phenotypically similar to the conventional propagated plants in production field.     

Stomatal patchiness in the Mediterranean holm oak (Quercus ilex L.) under water stress in the nursery and in the forest

The evergreen holm oak Quercus ilex L. is the most representative tree in Mediterranean forests. Accurate estimation of the limiting factors of photosynthesis for Q. ilex and the prediction of ecosystem water-use efficiency by mechanistic models can be achieved only by establishing whether this species shows heterogenic stomatal aperture, and, if so, the circumstances in which this occurs. Here, we collected gas-exchange and chlorophyll fluorescence data in Q. ilex leaves from a nursery to measure the effects of stomatal oscillations on PSII quantum yield (Φ(PSII)) under water stress. Stomatal conductance (g(s)) was used as an integrative indicator of the degree of water stress. Images of chlorophyll fluorescence showed heterogeneous Φ(PSII) when g(s) was <50 mmol H(2)O m(-2) s(-1), representative of severe drought and corresponding to a container capacity <45%. Stomatal patchiness was related to a coefficient of variation (CV) of Φ(PSII) values >2.5%. A parallel study in the forest confirmed heterogeneous Φ(PSII) values in leaves in response to declining water availability. Three kinds of Q. ilex individuals were distinguished: those resprouting after a clear-cut (resprouts, R); intact individuals growing in the same clear-cut area as resprouts (controls, C); and intact individuals in a nearby, undisturbed area (forest controls, CF). Patchiness increased in C and CF in response to increasing drought from early May to late July, whereas in R, Φ(PSII) values were maintained as a result of their improved water relations since the pre-existing roots were associated with a smaller aerial biomass. Patchiness was related to a % CV of Φ(PSII) values >4 and associated in the summer with mean g(s) values of 30 mmol H(2)O m(-2) s(-1). Under milder drought in spring, Φ(PSII) patchiness was less strictly related to g(s) variations, pointing to biochemical limitants of photosynthesis. The occurrence of heterogenic photosynthesis caused by patchy stomatal closure in Q. ilex during severe drought should be taken into account in ecosystem modelling in which harsher water stress conditions associated with climate change are predicted.     

The annual pattern of sap flow in two Eucalyptus species established in the vicinity of gold-mine tailings dams in central South Africa

Several hundred mine tailings dams occur in the Witwatersrand Basin Goldfields in central South Africa. Seepage of acid mine drainage (AMD) from these unlined structures is widespread, and a variety of contaminants is released into soil and groundwater. The ‘Mine Woodlands Project’ is aimed at evaluating the use of high-density tree stands over surrounding contaminant plumes to limit the spread of contaminants through hydraulic control of groundwater and enhanced uptake or immobilisation of contaminants. The annual pattern of hourly sap flow in four contiguous Eucalyptus dunnii trees (aged three years) was followed over a full year in a species trial situated near Carltonville. The annual pattern of hourly sap flow was also recorded in four contiguous sample trees (aged four years) of the clonal hybrid E. grandis × E. camaldulensis (E. G×C) at another trial near Orkney. Both species showed high sap flow rates close to reference evaporation rates in response to summer rains. Both showed greatly reduced sap flow rates during the latter half of the dry winter season. Sap flow rates only recovered after the arrival of the first spring rains. Annual sap flow (E. dunnii, 673 mm; E. G×C, 767 mm) was similar to the recorded annual rainfall at each site (E. dunnii, 629 mm; E. G×C, 795 mm), and was substantially lower than total annual reference evaporation (E. dunnii, 1 273 mm; E. G×C, 1 330 mm). We conclude that the roots of both species are not yet deep enough to access the AMD-influenced groundwater, which lies at depths of 14 and 10 m below the ground at the Carltonville and Orkney sites, respectively. Despite prolonged water deficits, both species survived well and maintained sufficient vigour to permit the quick recovery of high transpiration rates in the following summer. This resilience is essential to hasten root growth and improve the chance of contact with groundwater plumes.     

Multibiomarker response shows how native and non‐native freshwater bivalves differentially cope with heat‐wave events

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Correlation of testicular artery Doppler velocimetry with kinetics and morphologic characteristics of epididymal sperm in dogs

Sperm quality can be affected by a reduction in testicular blood flow, which can be measured by Doppler ultrasonography. The aim of this study was to correlate the Doppler velocimetry of the testicular artery with kinetics of the epididymal spermatozoa in dogs. Twenty-two dogs (44 testicles) were evaluated by Doppler ultrasonography in five regions of the testicular artery before orchiectomy. Spermatozoa were recovered by the epididymal tail compression technique and analysed for kinetics on a computer-assisted semen analysis (CASA system). Morphology (modified Karras) and sperm membrane integrity were analysed by eosin–nigrosine staining. Data were analysed by Pearson's correlation test (p < .01). The mean total motility was 69.0% ± 17.7, progressive motility was 43.7% ± 14.7, average path velocity (VAP) was 127.0 µm/s ± 20.7, curvilinear velocity (VCL) was 221.0 µm/s ± 31.1, and sperm velocity index (SVI) was 389.9 ± 56.1. There were positive correlations between the peak systolic velocity (PSV) in the proximal supratesticular region with the SVI (r = .529), VCL (r = .555) and VAP (r = .473), and a negative correlation with the percentage of slow spermatozoa (r = −.463). The results suggest that the testicular artery blood flow velocity can positively affect the speed of spermatozoa movement. For the first time, we have correlated sperm kinetics with the Doppler evaluation of the testicular artery in dogs.     

Genetic evaluation of IS900 partial sequence of Mycobacterium avium subsp. paratuberculosis Brazilian isolates from bovine milk

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis. Insertion sequence IS900 is used for the identification of MAP. The objective of this study was to verify the genetic conservation of IS900 sequences in raw milk samples. To evaluate genetic conservation, 206 quarter milk samples and 16 bulk-tank milk samples were collected. DNA extraction and IS900 PCR were performed in all samples. Six samples amplified the expected fragment. To confirm the identity of the amplified fragments, PCR products were cloned and sequenced. The resulting sequences were compared with other MAP sequences from GenBank, and it was possible to identify eight polymorphic regions and to form five distinct haplotypes. The number of mutations in each haplotype was verified. IS900 sequence is a very well-conserved sequence that could be used as tool for the molecular detection of this agent and epidemiological purposes. The results showed the first genetic analysis on Brazilian isolates of MAP.     

Effect of vitamin E supplementation and partial substitution of poly- with mono-unsaturated fatty acids in pig diets on muscle, and microsome extract alpha-tocopherol concentration and lipid oxidation.

The experiment was organized in a 3 x 2 factorial arrangement with three dietary fat blends and a basal (20 mg kg(-1) diet) or supplemented (220 mg kg(-1)) level of alpha-tocopheryl acetate. Dietary vitamin E and monounsaturated to polyunsaturated fatty acid ratio (dietary MUFA/PUFA) affected muscle alpha-tocopherol concentration (alpha-tocopherol [log microg g(-1)] = 0.18 (+/- 0.105) + 0.0034 (+/- 0.0003) x dietary alpha-tocopherol [mg kg(-1) diet] (P < 0.0001) + 0.39 (+/- 0.122) x dietary MUFA/PUFA (P < 0.0036)). An interaction between dietary alpha-tocopherol and dietary MUFA/PUFA exists for microsome alpha-tocopherol concentration (alpha-tocopherol [log microg g(-1)] = 1.14 ( +/- 0.169) (P < 0.0001) + 0.0056 ( +/- 0.00099) x dietary alpha-tocopherol [mg kg(-1) diet] (P <0.0001) + 0.54 (+/- 0.206) x dietary MUFA/PUFA (P < 0.0131) - 0.0033 (+/- 0.0011) x dietary alpha-tocopherol [mg kg(-1))] x dietary MUFA/PUFA (P < 0.0067)), and hexanal concentration in meat (hexanal [ng x g(-1)] = 14807.9 (+/- 1489.8)- 28.8 (+/- 10.6) dietary alpha-tocopherol [mg x kg(-1)] (P < 0.01) - 8436.6 (+/- 1701.6) x dietary MUFA/PUFA (P < 0.001) + 24.0 (+/- 11.22) x dietary alpha-tocopherol-dietary MUFA/ PUFA (P < 0.0416)). It is concluded that partial substitution of dietary PUFA with MUFA lead to an increase in the concentration of alpha-tocopherol in muscle and microsome extracts. An interaction between dietary alpha-tocopherol and fatty acids exists, in which at low level of dietary vitamin E inclusion, a low MUFA/ PUFA ratio leads to a reduction in the concentration of alpha-tocopherol in microsome extracts and a concentration of hexanal in meat above the expected values.