Fluorescence, browning index, and color in infant formulas during storage

Free and total fluorescent compounds, browning index, and color formation were measured in milk-based powdered infant formulas (IF) during 2 years of storage at 20 and 37 degrees C. The excitation spectra from 415 nm emission show three peaks (ex lambda1 = 270 nm, lambda2 = 325/315 nm, lambda3 = 350 nm) and from 347 nm excitation two emission peaks (415 and 520 nm), and no wavelength shifts were observed. Temperature and time of storage exert in general no significant effect on the development of fluorescence emission intensity and browning index. However, an important increase in pentodilysine was recorded-probably because of the iron and ascorbic acid contents of the samples-as well as in browning index in adapted IF. In both IF a color increase (deltaE) throughout storage was observed, this increase being greater in samples stored at 37 degrees C than in those stored at 20 degrees C. The increase in color with time fitted a linear regression model. Color appeared to be an indicator of sufficient sensitivity to measure the effect of temperature or storage time.     

A calorimetric study of thermal denaturation of recombinant human lactoferrin from rice

Thermal denaturation of recombinant human lactoferrin from transgenic rice with different degrees of iron saturation has been studied by differential scanning calorimetry. The maximum temperature, enthalpy change, and activation energy of denaturation were higher when recombinant lactoferrin was more saturated with iron, indicating an increase in the stability of the protein structure. Maximum temperature and activation energy values for apo- and holo-lactoferrins were practically identical to those reported for the same forms of lactoferrin from human milk, which indicates a similar thermal stability. However, the value of enthalpy change for denaturation of the recombinant lactoferrin was 2.5-3-fold lower than that found for the human milk protein. This finding may reflect the influence that the different glycosylation pattern may have in the relationship between lactoferrin domains. Denaturation of recombinant lactoferrin in milk was compared with denaturation in phosphate buffer, and results indicated that the protein was more heat-sensitive when treated in milk than in buffer.     

Role of Azospirillum brasilense nitrate reductase in nitrate assimilation by wheat plants

Summary The nitrogen metabolism of wheat plants inoculated with various Azospirillum brasilense strains and nitrate reductase negative (NR^–) mutants was studied in two monoxenic test tube experiments. The spontaneous mutants selected with chlorate under anaerobic conditions with nitrite as terminal electron acceptor fixed N₂ in the presence of 10 mM NO₃ ^– and were stable after the plant passage. One strain (Sp 245) isolated from surface-sterilized wheat roots produced significant increases in plant weight at both NO₃ levels (1 and 10 mM) which were not observed with the NR^– mutants or with the two other strains. Similar effects were observed in a pot experiment with soil on dry weight and total N incorporation but only at the higher N fertilizer level. In the monoxenic test tube experiments plants inoculated with the mutants showed lower nitrogenase activities than NR⁺ strains at the low NO₃ ^– level (1 = mM) but maintained the same level of activity with 10 mM NO₃ ^– where the activity of all NR⁺ strains was completely repressed. The nitrate reductase activity of roots increased with the inoculation of the homologous strains and with the mutants at both NO₃ ^– levels. At the low NO₃ ^– level this also resulted in increased activity in the shoots, but at the high NO₃ ^– level the two homologous strains produced significantly lower nitrate reductase activity in shoots while the mutants more than doubled it. The possible role of the bacterial nitrate reductase in NO₃ ^– assimilation by the wheat plant is discussed.     

Yield and nutritional requirements of cassava in response to potassium fertilizer in the second cycle

Potassium (K) is one of the most absorbed nutrients by cassava because it acts on the synthesis and starch accumulation in the storage roots. Here, we show that K application at the beginning of the second vegetative cycle of cassava submitted to shoot pruning increased the yield of roots and starch, and the nutrient demand of plants. Application of 45–89 kg ha^?1 dipotassium oxide (K₂O) in the second cycle increased the yield of storage roots and starch from 36–49% and K applied at this time had a greater effect on the synthesis and allocation of starch in the storage roots. K supply increased the accumulation of N and S by 2.0- to 3.0-fold and the accumulation of other nutrients by 1.4- to 1.7-fold. The removal of phosphorus (P), manganese (Mn), and zinc (Zn) by storage roots was not affected by K application, whereas the removal of other nutrients increased by 1.3- to 4.3-fold.     

Red deer (Cervus elaphus hispanicus) management in the dehesa system in Central Extremadura,Spain

In this paper we report the results of a study on the suitability of the dehesa (Mediterranean woodlands) as habitat of red deer (Cervus elaphus hispanicus) in a closed country estate of about 4300 ha total surface situated in the San Pedro Mountain, in Central Extremadura, Spain. We have described the deer management with respect to habitat, exploitation mode, deer feeding, population control and production of goods and services. It is concluded that the dehesa system is a rich natural resource that preserves and improves the degraded environment.

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Resumen En el presente trabajo se estudia la dehesa como hábitat del ciervo (Cervus elaphus hispanicus). Se ha tomado como referencia una finca cerrada de 4300 ha de ST situada en la Sierra de San Pedro, en Extremadura, España. Se describen los sistemas de gestión actuales del ciervo en cuanto a hábitat, modo de explotación, alimentación, control de población y producción de bienes y servicios. Concluyendo con la necesidad de fomentar este tipo de explotaciones cinegéticas de dehesa que ayudan a conservar y potenciar el medio ambiente en zonas despobladas y deprimidas

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Abbreviations CS collected surface - DMFCU deedmixed feed cattle units - Fi final inventory - FS fertilized surface - Ii Initial inventory - K Potassium - N Nitrogen - NBF number of breeding females - NBFIi number of breeding females of initial inventory - NBFR number of breeding females released - NBM number of breeding males - NBMIi number of breeding males of initial inventory - NBMR number of breeding males released - NCCR number of captive calves released - NCFi number of calves of final inventory - NCR number of calves released - NFR number of female renovation - NYMR number of young males released - NYFR number of young females released - P phosphorus - PP permanent Pastures - pts pesetas - QS Quercus stalks - RDED resources directly eaten by deer - SPOM selected hunted down poor quality males - SS sowed surface - TN total needs of deer - TNR total number released - UAS useable agrarian surface - WB wooded brush - WQS wooded Quercus surface - WS wooded surface     

Field validation of chlordecone soil sequestration by organic matter addition

Purpose

The use of chlordecone (CLD) has caused pollution of soils, which are now a source of contamination for crops and ecosystems. Because of its long-term impacts on human health, exposure to CLD is a public health concern and contamination of crops by CLD must be limited. To this end, we conducted field trials on chlordecone sequestration in soil with added compost.

Materials and methods

The impact of added compost on chlordecone sequestration was measured in nitisols. After characterization of the soil, the transfer of chlordecone from soil to water was assessed in a leaching experiment and from soil to two crop plants in a nitisol plot. Finally, to understand the underlying processes, changes in CLD content were measured in soil fractions and soil porous properties were assessed after the addition of compost.

Results and discussion

A rapid seven-fold decrease in water extractable CLD was observed in amended soils. Five percent amendment led to a significant reduction in the contamination of crops by CLD; edible radish tubers were 50% more contaminated without added compost and cucumber fruits were 60% more contaminated. After the addition of compost, CLD content increased in the fraction of pre-humified or partially mineralized organic debris. Finally, in contrast to andosols, adding compost to nitisols did not affect the soil microstructure.

Conclusions

Increasing chlordecone sequestration by adding compost could be an alternative solution until soil decontamination techniques become available. This could be a provisional way to control further release of CLD from contaminated soils towards other environmental compartments.     

A follow-up of Beagle dogs intradermally infected with Leishmania chagasi in the presence or absence of sand fly saliva

In this study, we compare the development of infection and/or disease in Beagle dogs intradermally infected with Leishmania chagasi, in the presence or absence of Lutzomyia longipalpis saliva, with those of intravenously infected animals.Spleen samples of all the animals inoculated with parasites had positive polymerase chain reaction tests for Leishmania DNA. Positive spleen cultures for Leishmania were detected earlier (P < or = 0.018) and were more frequent (five out of the five animals) in intravenously infected animals than in the intradermally infected animals, in presence (two out of the six animals) or absence (three out of the five animals) of salivary gland lysate of L. longipalpis. Significant increase in serum antibodies against Leishmania was observed only in the intravenously infected group (P = 0.004). In addition, dogs with infection confirmed by isolation of amastigotes or detection of parasite DNA were, nevertheless, negative for anti-Leishmania antibodies up to 5 months or more after infection. Only animals of the intravenously infected group developed progressive decreases in hematocrit (Pearson r = -0.8076, P = -0.0026) and hemoglobin (Pearson r = -0.8403, P = 0.0012) during the infection period. No significant difference in the course of infection was observed between groups of intradermally infected animals. The data presented herein confirms that the intradermal inoculation of dogs with Leishmania produces an asymptomatic form of infection. It also fails to show an advantage in using L. longipalpis saliva as an infection-enhancing agent in experimental canine leishmaniasis.     

Sap flow in papaya plants: Laboratory calibrations and relationships with gas exchanges under field conditions

In papaya plants a study to quantify the water flow through the trunk is important for to promote a good water management in commercial orchard. The objective was to study the relationship between water flow through the trunk and temperature measurements determined by probes inserted in the papaya plant stem in laboratory. In addition, was possible to study the relationship between sap flow and instantaneous gas exchange in field conditions. We constructed an instrument that maintained a stable water flux through a 0.30 m stem section with a constant pressure, simulating the xylem sap flow through the stem. Water flux was adjusted by varying pressure of water in the stem section. The mathematical model used to fit the relation between K (Granier heat coefficient) values and sap flow density was the exponential model: u = 0.5511 × K^1.9104. Field studies was conducted in a commercial orchard located in North of the State of Rio de Janeiro, with 12 plants in October 2002, and eight plants in January 2003. We verified that instantaneous transpiration, measured by a portable system of gas exchange (porometry), presented a good (R² = 0.75) positive relationship with xylem sap flow. Estimates of papaya sap flow can be obtained by scaling portable photosynthesis system measurements with exposed leaves, however the relationship is non-linear in higher instantaneous transpiration rates. The causes of the non-linear relationship in higher transpiration are discussed. In addition, was possible to obtain a good (R² = 0.76) relationship between net photosynthesis rate and xylem sap flow in papaya field-grown.