Variation of extractives content in heartwood and sapwood of Eucalyptus globulus trees

The variation in extractives content in sapwood and heartwood was investigated among 12 trees in each of four commercial plantations of Eucalyptus globulus in central Portugal. The study was carried out at the 15% height level and extractions used successively dichloromethane, ethanol and water. At all sites, heartwood had significantly more extractives than sapwood, on average 3.8 and 2.4%, respectively. Most extractives consisted of ethanol soluble material (on average 52% of total extractives). Among the sites, there was a statistically significant difference in the content of extractives but the most important source of variation was the within-tree variation between sapwood and heartwood. Differences in the content of extractives were also observed among trees. A strong relation between extractives content and heartwood proportion was found. The potential loss of pulp yield and problems associated with accumulation of extractives are directly related to the heartwood proportion in the eucalypt stems. Forest management should take into account heartwood development and selection for minimising heartwood extractives.     

A multiplex PCR for the detection of Brucella spp. and Leptospira spp. DNA from aborted bovine fetuses

Bovine brucellosis and leptospirosis are important causes of bovine abortion around the world. Both diseases can be serologically diagnosed, but many factors may cause false positive and negative results. Direct methods based on bacteriological isolation are usually employed, but they are difficult, time consuming and dangerous. Monoplex polymerase chain reaction (PCR) have been successfully described for the detection of Brucella spp. and Leptospira spp. Aiming at improvement in the direct diagnosis, a multiplex PCR (mPCR) for the detection of these agents in aborted bovine fetuses is described. The detection threshold of the mPCR was evaluated in experimentally contaminated bovine clinical samples using a conventional proteinase K/SDS or a boiling-based extraction protocols. The mPCR was applied to two groups of clinical samples: 63 episodes of bovine abortion and eight hamsters experimentally infected with Leptospira interrogans serovar pomona. Adopting microbiological isolation as reference, the test showed a sensitivity of 100% in both groups of clinical samples. Seven samples collected from bovine fetuses were Brucella spp. culture negative but showed positive results in mPCR. Regarding Leptospira spp. detection, similar results were observed in three bovine clinical samples. All hamsters infected with Leptospira were positive in both microbiological culture and mPCR. The boiling extraction protocol showed better results in some clinical samples, probably by the removal of PCR inhibitors by heat treatment. The high sensitivity, simplicity and the possibility of detection of both bacteria in a single tube reaction support the use of the mPCR described in the routine diagnosis.     

Postpartum Ovarian Activity in South Asian Zebu Cattle

Timely onset of postpartum ovarian activity is vital for optimal reproductive performance of dairy cows. Much depends upon genetic constitution of an animal although several factors interplay to govern the onset of postpartum ovarian activity. South Asian zebu cattle have much longer service period when compared with other exotic or crossbred cattle reared in the same Asian environment, which suggests differences in their genetic makeup. However, the cows with same genetic configuration expressed better reproductive potential when reared under different environment, such as in Brazil and Mexico, which suggests the role of extrinsic factors such as management, nutrition, environment and disease conditions. Better management of animals (provision of proper shade, water and housing, efficient oestrous detection and timely insemination), good quality nutrition supplemented with appropriate minerals and vitamins, prevention of diseases (vaccination, deworming, suitable therapeutic interventions) and application of biotechnology have helped in improving postpartum ovarian activity and, therefore, reproductive performance of zebu cattle in Asia. No comprehensive study appears to have been carried out on the various aspects of reproduction in zebu cattle reared under South Asian socio-agro-climatic conditions. This paper is a modest effort to collect what ever information available and to critically review the postpartum ovarian activity in zebu cattle with special reference to the effect of the various managemental practices and pharmacological interventions.     

Metabolic alkalosis: a quick reference.

This article serves as a quick reference for metabolic alkalosis. Guidelines for analysis and causes, signs, and a stepwise approach are presented.     

Spray-drying of the microalga Dunaliella salina: effects on beta-carotene content and isomer composition.

The effects of spray-drying of the unicellular microalga Dunaliella salina on its beta-carotene content and geometric isomer composition have been studied. The efficacy of a range of synthetic and natural antioxidants in preventing degradation of beta-carotene has been determined. Losses of beta-carotene and isomerization were minimal during processing for both the control (no exogenous antioxidants) and the samples containing butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). However, the use of tocopherol-based antioxidants resulted in degradation of 52-72% of beta-carotene during the drying process. All dried powders of Dunaliella proved to be unstable during storage in the presence of light and air, with beta-carotene degraded according to a first-order kinetic model. Of the antioxidants studied, only TBHQ was successful in significantly minimizing degradation (degradation constants of 0.03 and 0.04 days(-)(1), compared to 0.53 days(-)(1) for the respective control). For control powders and those with BHT added to the feed, the degradation constants were reduced to values between 0.27 and 0.37 days(-)(1) by restricting light and flushing with nitrogen; however, storage in the dark alone had no effect. For more slowly degrading powders having TBHQ added to the feed, it was clear that degradation of beta-carotene was influenced by both light and oxygen. During storage the 9-cis isomer of beta-carotene was significantly more unstable than the all-trans form. TBHQ was, however, successful in reducing relative losses of this isomer for samples stored in the dark. The results suggest a dominant photodegradative mechanism for the loss of the 9-cis isomer of beta-carotene.     

Effectiveness of early-generation testing applied to upland rice breeding

A plant breeding program is a long-term investment. Therefore, periodic assessment of the effectiveness of a breeding strategy is essential to maximize genetic gains per unit of time and resource invested. In this work, we assessed the effectiveness of the early-generation testing (EGT) approach used in the upland rice (Oryza sativa L.) breeding program at Embrapa (Brazilian Agricultural Research Corporation), Brazil, estimating the genetic progress achieved for three traits in two distinct phases, spanning 15 years. In the first phase (from 2003 to 2010), it was used the bulk method within F₃ progenies with prior testing of F₂ crosses, while in the second phase (from 2010 to 2017), it was used the bulk method within F₂ progenies. The dataset comprised 70 yield trials, involving 1884 F_3:5 progenies (phase I) and 925 F_2:4 progenies (phase II) from an elite population, and 10 check cultivars, evaluated for grain yield (GY), plant height (PH) and days to flowering (DTF). For estimating the genetic gain, we adapted a generalized linear regression method to compute bi-segmented linear regression coefficients. Desirable genetic gains were achieved only for GY in both phases of the breeding program, with 78.75 kg ha^?1 year^?1 (2.68%) in the first phase, and 53.78 kg ha^?1 year^?1 (1.54%) in the second phase. These results show the effectiveness of EGT, especially via bulk method within F₃ progenies with prior testing of F₂ crosses, applied to upland rice breeding. Some refinements are discussed in the method to make it more cost-effective and more efficient in achieving genetic gains.     

Carotenoids from Marine Microalgae: A Valuable Natural Source for the Prevention of Chronic Diseases

Epidemiological studies have shown a relation between antioxidants and the prevention of several chronic diseases. Microalgae are a potential novel source of bioactive molecules, including a wide range of different carotenoids that can be used as nutraceuticals, food supplements and novel food products. The objective of this review is (i) to update the research that has been carried out on the most known carotenoids produced by marine microalgae, including reporting on their high potentialities to produce other less known important compounds; (ii) to compile the work that has been done in order to establish some relationship between carotenoids and oxidative protection and treatment; (iii) to summarize the association of oxidative stress and the various reactive species including free radicals with several human diseases; and (iv) to provide evidence of the potential of carotenoids from marine microalgae to be used as therapeutics to treat or prevent these oxidative stress-related diseases.