Assessment of genetic differentiation among relict populations of Calophyllum brasiliense Camb. (Calophyllaceae) from Northeast Argentina

Calophyllum brasiliense is a tropical tree that grows exclusively in riparian forest and in almost permanently flooded areas. In Argentina two small populations located within riparian forest from Misiones and Corrientes Provinces have been recently identified. These riparian communities have been extensively fragmented and are at risk of local extinction due to flooding caused by a nearby dam and other anthropogenic changes that threaten this habitat. Genetic characterization using information from 56 RAPD loci revealed low expected heterozygosity in both populations (He = 0.273). Most genetic variability was distributed within populations, and a significant ϕST statistic value (0.283, p<0.05) showed the existence of a large genetic differentiation between them. Furthermore, the SGS analysis revealed a nonrandom distribution of genotypes in Misiones? population. Although these populations could have belonged to a large and continuous forest in the past, the process of habitat fragmentation may have favoured the divergence between them; sufficient time has passed to cause their genetic differentiation. As these populations represent the new southernmost species distribution, the genetic information obtained in this study should be analyzed in conjunction with ecological evaluations in order to develop management strategies that can ensure its conservation.Laboratorio de Sistemática y Biología Evolutiv

Assessment of genetic differentiation among relict populations of Calophyllum brasiliense Camb. (Calophyllaceae) from Northeast Argentina

Calophyllum brasiliense is a tropical tree that grows exclusively in riparian forest and in almost permanently flooded areas. In Argentina two small populations located within riparian forest from Misiones and Corrientes Provinces have been recently identified. These riparian communities have been extensively fragmented and are at risk of local extinction due to flooding caused by a nearby dam and other anthropogenic changes that threaten this habitat. Genetic characterization using information from 56 RAPD loci revealed low expected heterozygosity in both populations (He = 0.273). Most genetic variability was distributed within populations, and a significant ϕST statistic value (0.283, p<0.05) showed the existence of a large genetic differentiation between them. Furthermore, the SGS analysis revealed a nonrandom distribution of genotypes in Misiones? population. Although these populations could have belonged to a large and continuous forest in the past, the process of habitat fragmentation may have favoured the divergence between them; sufficient time has passed to cause their genetic differentiation. As these populations represent the new southernmost species distribution, the genetic information obtained in this study should be analyzed in conjunction with ecological evaluations in order to develop management strategies that can ensure its conservation.Laboratorio de Sistemática y Biología Evolutiv

Efecto de dos protocolos de antisepsia del campo operatorio sobre la reducción del número de bacterias de la piel en bovinos sometidos a cirugías reproductivas a campo

The effect of two surgical field antisepsis protocols on the reduction of the number of skin bacteria in bovines subjected to field reproductive surgeries was determined. Samples were taken before (M1), and after antisepsis (M2) and at the end of the surgical procedure (M3) in 12 crossbred bovines aged 12 to 24 months. Trichotomy of the operating field was performed prior to the two antisepsis protocols: 7.5% povidone-iodine and 2% Chlorhexidine Gluconate (both with 3-min contact time and 2-min contact clearance with isopropyl alcohol) and later embrocation with 1% povidone-iodine solution and 0.5% chlorhexidine solution, respectively. The skin swabs were processed by the count technique of colony forming units (CFU/ml). The bacterial load of the two protocols was analysed with the Mann-Whitney-Wilcoxon test for independent samples, without finding significant differences between protocols by evaluation time (p˃0.05). The Friedman test indicated a significant reduction between M1 with M2 and M3 (p&lt;0.05), but not between M2 and M3 (p&gt;0.05).Se determinó el efecto de dos protocolos de antisepsia del campo operatorio sobre la reducción del número de bacterias de la piel en bovinos sometidos a cirugías reproductivas a campo. Se tomaron muestras antes (M1,) luego de la antisepsia (M2) y al finalizar el procedimiento quirúrgico (M3) en 12 12 bovinos mestizos de 18 a 24 meses de edad. Se realizó la tricotomía del campo operatorio previo a los dos protocolos de antisepsia: Iodopovidona al 7.5% y Gluconato de Clorhexidina al 2% (ambos con 3 min de contacto y aclaramiento con alcohol isopropílico de 2 min de contacto) y posterior embrocado con iodopovidona solución al 1% y clorhexidina solución al 0.5%, respectivamente. Los hisopados de piel fueron procesadas por la técnica de recuento de unidades formadoras de colonias (UFC/ml). La carga bacteriana de los dos protocolos fue analizada con el test de Mann-Whitney-Wilcoxon para muestras independientes, sin encontrar diferencias significativas entre protocolos por momento de evaluación (p˃0.05). El test de Friedman indicó una reducción significativa entre M1 con M2 y M3 (p&lt;0,05), pero no entre M2 y M3 (p&gt;0.05)

Phytochemicals as antibiotic alternatives to promote growth and enhance host health

There are heightened concerns globally on emerging drug-resistant superbugs and the lack of new antibiotics for treating human and animal diseases. For the agricultural industry, there is an urgent need to develop strategies to replace antibiotics for food-producing animals, especially poultry and livestock. The 2nd International Symposium on Alternatives to Antibiotics was held at the World Organization for Animal Health in Paris, France, December 12-15, 2016 to discuss recent scientific developments on strategic antibiotic-free management plans, to evaluate regional differences in policies regarding the reduction of antibiotics in animal agriculture and to develop antibiotic alternatives to combat the global increase in antibiotic resistance. More than 270 participants from academia, government research institutions, regulatory agencies, and private animal industries from >25 different countries came together to discuss recent research and promising novel technologies that could provide alternatives to antibiotics for use in animal health and production; assess challenges associated with their commercialization; and devise actionable strategies to facilitate the development of alternatives to antibiotic growth promoters (AGPs) without hampering animal production. The 3-day meeting consisted of four scientific sessions including vaccines, microbial products, phytochemicals, immune-related products, and innovative drugs, chemicals and enzymes, followed by the last session on regulation and funding. Each session was followed by an expert panel discussion that included industry representatives and session speakers. The session on phytochemicals included talks describing recent research achievements, with examples of successful agricultural use of various phytochemicals as antibiotic alternatives and their mode of action in major agricultural animals (poultry, swine and ruminants). Scientists from industry and academia and government research institutes shared their experience in developing and applying potential antibiotic-alternative phytochemicals commercially to reduce AGPs and to develop a sustainable animal production system in the absence of antibiotics.Fil: Lillehoj, Hyun. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Liu, Yanhong. University of California; Estados UnidosFil: Calsamiglia, Sergio. Universitat Autònoma de Barcelona; EspañaFil: Fernandez Miyakawa, Mariano Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Chi, Fang. Amlan International; Estados UnidosFil: Cravens, Ron L.. Amlan International; Estados UnidosFil: Oh, Sungtaek. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Gay, Cyril G.. United States Department of Agriculture. Agricultural Research Service; Argentin

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

Epidemiology of Streptococcus pneumoniae and Staphylococcus aureus colonization in healthy Venezuelan children

Streptococcus pneumoniae and Staphylococcus aureus cause significant morbidity and mortality worldwide. We investigated both the colonization and co-colonization characteristics for these pathogens among 250 healthy children from 2 to 5 years of age in Merida, Venezuela, in 2007. The prevalence of S. pneumoniae colonization, S. aureus colonization, and S. pneumoniae–S. aureus co-colonization was 28%, 56%, and 16%, respectively. Pneumococcal serotypes 6B (14%), 19F (12%), 23F (12%), 15 (9%), 6A (8%), 11 (8%), 23A (6%), and 34 (6%) were the most prevalent. Non-respiratory atopy was a risk factor for S. aureus colonization (p = 0.017). Vaccine serotypes were negatively associated with preceding respiratory infection (p = 0.02) and with S. aureus colonization (p = 0.03). We observed a high prevalence of pneumococcal resistance against trimethoprim–sulfamethoxazole (40%), erythromycin (38%), and penicillin (14%). Semi-quantitative measurement of pneumococcal colonization density showed that children with young siblings and low socioeconomic status were more densely colonized (p = 0.02 and p = 0.02, respectively). In contrast, trimethoprim–sulfamethoxazole- and multidrug-resistant-pneumococci colonized children sparsely (p = 0.03 and p = 0.01, respectively). Our data form an important basis to monitor the future impact of pneumococcal vaccination on bacterial colonization, as well as to recommend a rationalized and restrictive antimicrobial use in our community

Pαx6 Expression in Postmitotic Neurons Mediates the Growth of Axons in Response to SFRP1

During development, the mechanisms that specify neuronal subclasses are coupled to those that determine their axonal response to guidance cues. Pax6 is a homedomain transcription factor required for the specification of a variety of neural precursors. After cell cycle exit, Pax6 expression is often shut down in the precursor progeny and most postmitotic neurons no longer express detectable levels of the protein. There are however exceptions and high Pax6 protein levels are found, for example, in postmitotic retinal ganglion cells (RGCs), dopaminergic neurons of the olfactory bulb and the limbic system in the telencephalon. The function of Pax6 in these differentiating neurons remains mostly elusive. Here, we demonstrate that Pax6 mediates the response of growing axons to SFRP1, a secreted molecule expressed in several Pax6-positive forebrain territories. Forced expression of Pax6 in cultured postmitotic cortical neurons, which do not normally express Pax6, was sufficient to increment axonal length. Growth was blocked by the addition of anti-SFRP1 antibodies, whereas exogenously added SFRP1 increased axonal growth of Pax6-transfected neurons but not that of control or untransfected cortical neurons. In the reverse scenario, shRNA-mediated knock-down of Pax6 in mouse retinal explants specifically abolished RGCs axonal growth induced by SFRP1, but had no effect on RGCs differentiation and it did not modify the effect of Shh or Netrin on axon growth. Taken together these results demonstrate that expression of Pax6 is necessary and sufficient to render postmitotic neurons competent to respond to SFRP1. These results reveal a novel and unexpected function of Pax6 in postmitotic neurons and situate Pax6 and SFRP1 as pair regulators of axonal connectivity