Fragmentation Status of Tall-Tussock Grassland Relicts in the Flooding Pampa,Argentina

Since European settlement vast areas of the tall tussock grassland dominated by Paspalum quadrifarium Lam. and Paspalum exaltatum J. Presl (“pajonal” grassland) in the Flooding Pampa of Argentina were converted to croplands and short grasslands. With the use of Landsat satellite images, we analyzed current (1998–2000) cover and spatial integrity of the pajonal community, and compared it with a vegetation map made 50 yr ago (1956–1960). Six categories of land cover were adopted: crops, sown pastures, short grassland, pajonal, wetlands, and anthropogenic areas. With the use of metrics from FRAGSTATS, landscape pattern and composition were analyzed at two scales: 1) regionally, by comparing two edaphic domain areas with relatively low and high restrictions for agriculture (low-restriction domain [LRD] and high-restriction domain [HRD], respectively); and 2) at landscape scale, by comparing ten 22 500-ha randomly selected areas (landscapes) within each edaphic domain. Current relative cover of pajonal grassland (2 173 600 ha) was 32.5%, and similar values were obtained within each edaphic domain. However, the number of pajonal patches was higher and their mean patch size, the Euclidean nearest-neighbor distance among patches (degree of isolation), and their border regularity were lower in the LRD than in the HRD. At landscape scale, the mean size of pajonal patches diminished with the percent of agricultural land within both edaphic domains. The isolation among pajonal patches increased with percent of agricultural land in the HRD, whereas no relationship between the isolation of pajonal patches and percent of agriculture was found in the LRD. As suggested by comparison with past vegetation, current pajonal status mostly results from replacement of pajonal grassland by short grassland types, cultivated pastures, and annual crops (52% and 44% of previously occupied areas in LRD and HRD, respectively), but some expansion of pajonal grassland was also observed (10% and 4% of previously unoccupied areas in LRD and HRD, respectively).     

Breed differences in calving interval in the humid Mexican tropic

The objective of this study was to evaluate the influence of breed, breed and sex of the calf, farm, calving number (CN), type of calving, and their interactions on CI using records from four different beef breeds performing in the humid tropical environment of Mexico. The influence of these factors on CN was also evaluated. CI and CN varied with farm, breed of the dam, and with breed of the dam by calf breed interaction (P<0.001), while CI also varied with CN. Significant differences between Bos indicus and Bos taurus breeds for CI (432 vs. 488 days) and for CN (2.13 vs. 1.92) were observed (P<0.001). The interaction effects observed between breed of the dam by breed of the calf on CI and on CN were due to a favorable F₁ calf effect on CI observed only in Angus cows, although with an apparent unexpected negative impact on CN.     

Technological Properties of Biodegradable Films Produced with Myofibrillar Proteins Extracted from Gilded cat-fish (Brachyplatystoma rousseauxii) Carcasses and Parings

ABSTRACT

This paper aimed to investigate whether the type of fish residue used for extraction of myofibrillar proteins (MP) impacts the technological properties of biodegradable films. The MPs were extracted from two types of Gilded cat-fish (Brachyplatystoma rousseauxii) residues: (1) carcass with muscle attached from the production of mechanically separated meat (MSM) and (2) parings from fillet trimming (PAR). The percentage composition and color of the MPs from MSM (P-MSM) and parings (P-PAR) significantly differed, mainly regarding the ash and lipid contents. The presence of these non-protein compounds in P-MSM led to the formation of films with inferior technological and thermal properties, which indicates the type of residue used impacted the film properties.     

Haloarchaea as Cell Factories to Produce Bioplastics

Plastic pollution is a worldwide concern causing the death of animals (mainly aquatic fauna) and environmental deterioration. Plastic recycling is, in most cases, difficult or even impossible. For this reason, new research lines are emerging to identify highly biodegradable bioplastics or plastic formulations that are more environmentally friendly than current ones. In this context, microbes, capable of synthesizing bioplastics, were revealed to be good models to design strategies in which microorganisms can be used as cell factories. Recently, special interest has been paid to haloarchaea due to the capability of some species to produce significant concentrations of polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), and polyhydroxyvalerate (PHV) when growing under a specific nutritional status. The growth of those microorganisms at the pilot or industrial scale offers several advantages compared to that of other microbes that are bioplastic producers. This review summarizes the state of the art of bioplastic production and the most recent findings regarding the production of bioplastics by halophilic microorganisms with special emphasis on haloarchaea. Some protocols to produce/analyze bioplastics are highlighted here to shed light on the potential use of haloarchaea at the industrial scale to produce valuable products, thus minimizing environmental pollution by plastics made from petroleum.     

Discovery and molecular characterization of a group A rotavirus strain detected in an Argentinean vicuña (Vicugna vicugna)

The wild vicuña (Vicugna vicugna) is one of the four species of native South American camelids (SACs) in addition to the wild guanaco, and their domesticated counterparts, alpaca and llama, respectively. Serological data have indicated the presence of group A rotaviruses (RVA) specific antibodies in all 4 members of the SAC, and so far, RVA has been detected from alpacas, llamas and guanacos. A total of 59 fecal samples from healthy wild newborn and juvenile vicuñas, raised in captivity in Jujuy, Argentina were collected and analyzed by ELISA to detect RVA antigen. Two samples (3%) were found to contain G8 RVA strains and one strain (RVA/Vicuña-wt/ARG/C75/2010/G8P[14]) was selected for further genome analyses, revealing the G8-P[14]-I2-R2-C2-M2-Ax-N2-T6-E3-Hx genotype constellation. Unfortunately, no sequence data could be obtained for NSP1 and NSP5. Except for the E3 NSP4 genotype, this partial genotype constellation is reminiscent to bovine RVA strains and bovine-like RVA strains isolated from sheep, guanaco, antelope and humans. This relationship was confirmed phylogenetically, providing further evidence of the widespread presence of this genotype constellation in animals belonging to the artiodactyls. In particular, a close phylogenetic relationship was found between C75 and guanaco RVA strain RVA/Guanaco-wt/ARG/Chubut/1999/G8P[14] for at least 5 gene segments, suggesting a partial conservation of the genotype constellation of RVA strains infecting different species of SACs, even though nowadays their natural habitats are not overlapping. The further monitoring of the sanitary health of wild newborn and juvenile vicuñas is essential to improve the management practices applied in their sustainable exploitation.     

Replacing methyl bromide in annual strawberry production with glucosinolate-containing green manure crops

The use of biocidal green manure crops is an agronomic technique for amending soil with fresh organic matter containing volatile compounds active in controlling some soil-borne pests and diseases. Two new selections of the Brassicaceae family were cultivated, incorporated before planting strawberries and tested as an alternative to fumigation with methyl bromide. Two biocidal green manure crops (Brassica juncea L sel ISCI20, Eruca sativa Mill cv Nemat) containing glucosinolate-myrosinase systems, a conventional green manure (barley), untreated soil and a fumigated control were evaluated during two seasons. The effect of these soil management systems on subsequent strawberry performance was evaluated by monitoring yield and plant growth parameters. In both years, biocidal plant green manure treatments led to a fruit yield lower than with methyl bromide, but higher than with conventional green manure or untreated soil. These results confirm the good prospects for biocidal green manures, not only as an environmentally friendly alternative to methyl bromide in conventional agriculture, but also in organic agriculture as an alternative to conventional green manure crops.     

Behaviour and welfare of fattening lambs supplemented with varying sizes and types of straw

The aim was to evaluate the effect of size (long or chopped wheat straw), type (barley or wheat) and presence/absence (1 week) of straw supplementation on behaviour and welfare of fattening lambs. Sixteen lambs (65 days) were individually housed to be used in two simultaneous experiments (8 lambs each) for 5 weeks of fattening. After a habituation period, they were offered straw that differed either in size (Experiment 1) or type (Experiment 2), which was followed by a week without straw and then reallocation of straw. Maintenance behaviours, play and stereotypies were analysed using video recording. Physiological stress responses were measured using blood samples taken at the end of the week without straw and after the reallocation of the straw. A preference test was performed during the last week. Concentrate and roughage consumption, average daily gain and conversion index were estimated. Lambs provided with long straw spent more time eating forage, playing and performed fewer stereotypies (Experiment 1). Lambs given wheat straw increased their play behaviour compared with those given barley straw, without affecting stereotypies (Experiment 2). When the straw was removed, lambs performed more behaviours associated with stress; however, this was not reflected in blood stress indicators. Lambs clearly preferred long straw over chopped straw, but no clear preference was observed between wheat and barley straw. The amount of forage intake was consistent with the time spent eating forage, but the amount of concentrate intake did not vary with eating concentrate behaviour, since the amount of concentrate intake was higher when the straw was removed, especially in Experiment 2. Our results show that size more than type of straw supplement impact the behaviour of lambs. Long straw reduces the stereotypies and increases play. This may improve the welfare and performance of fattening lambs, adding ethical value to a highly appreciated product.     

Foliar fertilization of peach (Prunus persica (L.) Batsch) with different iron formulations: Effects on re-greening,iron concentration and mineral composition in treated and untreated leaf surfaces

A trial to assess the effects of applying several Fe-containing formulations on Fe-deficient (chlorotic) peach leaves was carried out under field conditions. Solutions consisting of an Fe-containing compound (FeSO₄·7H₂O, Fe(III)–citrate, Fe(III)–EDTA, Fe(III)–DTPA or Fe(III)–IDHA) and one of five different surfactant treatments (no surfactant, an organo-silicon, an ethoxylated oil, a non-ionic alkyl polyglucoside and a household detergent) were applied to one half of the leaf via dipping, first at the beginning of the trial and then after 4 weeks. The re-greening of treated and untreated leaf areas was estimated with a SPAD apparatus, on a weekly basis, during 8 weeks. At the end of the experimental period, leaves were detached, and tissue Fe, N, P, K, Ca, Mg, Mn, Zn and Cu concentrations were determined in Fe-treated and untreated leaf areas. Treatment with Fe-containing solutions always resulted in leaf chlorophyll (Chl) increases, which however significantly depended on the Fe-source, the surfactant-type and the combination between both formulation components. Untreated leaf zones experienced a Chl increase only in some cases, and this depended on the type of surfactant used. Iron application significantly increased the Fe concentration of treated and untreated leaf areas, especially with some formulations. Foliar treatment with Fe-containing solutions induced significant changes in the concentration of several nutrients as compared to those found in Fe-deficient peach leaves, with changes being similar in treated and untreated leaf areas, although in some elements the extent of the changes was of a different magnitude in both materials. This indicates that some leaf mineral composition changes typical of chlorotic leaves are dependent on leaf Fe concentration rather than on leaf Chl levels. Results obtained are relevant to help understand the factors involved in the penetration and bioavailability of leaf-applied Fe, and to assess the potential of foliar Fe fertilization to control Fe deficiency in fruit trees.     

Wild halophytic species as forage sources: Key aspects for plant breeding

The use of wild halophytic species as forage resources in saline environments has gained increasing attention. Argentina ranks third in area of saline soils in the world, with a third of its territory showing various degrees of salinity, sodicity and/or alkalinity. On this type of soils, rangelands are the main forage resource for livestock production. Many wild species have forage potential and can also be used for the rehabilitation of rangelands and for intercropping. Information about these species, as well as on the physiological and genetic bases associated with salinity tolerance, provides relevant tools for efficient selection methods. This study addresses Argentine wild halophyte species with forage potential and describes selection criteria with an emphasis on the following taxa: (a) Poaceae: subfamily Chloridoideae and tribes Paniceae and Triticeae, (b) Fabaceae and (c) Amaranthaceae (formerly known as Chenopodiaceae). The review is intended to contribute to the general discussion on strategies for the improvement of wild plant genetic resources, using forage species naturally growing in saline soils in Argentina as a case study.