Factors that influence the decision to pursue an internship: the importance of mentoring

The purpose of the present study was (1) to determine if students from one veterinary school who participated in a mentoring/employment program with clinical faculty were more likely to pursue internship training than their peers and (2) to determine factors via survey that were influential to veterinary interns in making their decision to pursue post-graduate clinical training. Our hypothesis was that a mentoring relationship with clinical faculty was an important influence on the decision to participate in an internship. From 2006 to 2010, graduating students who participated in a mentoring/employment program with a clinical faculty member were 6.3 times more likely than non-participating students to pursue an internship. The majority of the participating students (90%) were initially hired/mentored as first- or second-year veterinary students. In the survey, interns ranked clinical faculty as having a greater influence than basic science faculty, private practice veterinarians, or house officers on their decision to pursue an internship; 82.8% reported that clinical faculty were most responsible for encouraging them to apply for an internship. Employment by their veterinary teaching hospital (41.5%) or directly by clinical faculty (26.2%) was commonly reported. Most interns (37%) decided to pursue an internship during their fourth year of veterinary school, 29.2% decided during their first year, and 15.3% decided in their second year. These results suggest that clinical faculty play a key role in a student's decision to pursue an internship and that it might be valuable to inform students about internships early in the veterinary curriculum.     

The risks of success in quality vegetable markets: Possible genetic erosion in Marmande tomatoes (Solanum lycopersicum L.) and consumer dissatisfaction

Following consumer complaints about the quality of modern varieties of tomato, landraces have strengthened their quality markets. In Spain, two tomato landraces, ‘Montserrat’ and ‘Pera Girona’, are grown in contiguous areas and have different market niches. We used amplified fragment length polymorphism (AFLP) to characterize 13 accessions of Montserrat, 14 accessions of Pera Girona, and 4 control varieties. We found a narrow genetic base for ‘Montserrat’ and ‘Pera Girona’ (8.5% of polymorphic loci) and no differences between the landraces. We studied agronomical and sensory traits to determine why the two landraces continue to have separate market niches. We found high variability among accessions within each landrace and overlapping among accessions of both landraces for all traits except fruit morphology. Consumers probably came to associate the organoleptic quality of these landraces with their external traits, but due to spontaneous crossings and introgressions these relations have been lost. Selection within landraces will be necessary to reestablish the link between morphology and sensory value and to consolidate these quality markets.     

Meloidogyne virulence locus molecular marker for characterization of selected mi-virulent populations of Meloidogyne spp. is correlated with several genera of betaproteobacteria

Resistance to root-knot nematodes in tomato is conferred by the Mi resistance gene to the three most important species of Meloidogyne: M. arenaria, M. incognita, and M. javanica. Nevertheless, the Mi gene is unable to inhibit the reproduction of selected and naturally Mi-virulent populations of root-knot nematodes. As pathogenicity assays are time consuming, molecular markers were developed for the easy identification of Mi-virulent populations of Meloidogyne. The sequence characterized amplified region-Meloidogyne virulence locus (MVC) molecular marker is reported to differentiate Mi-avirulent and naturally Mi-virulent from selected Mi-virulent populations. This marker was used to compare acquired virulence in populations of M. javanica from Spain. The original populations used to develop the MVC marker were included as control for reference. Results showed that this marker did not amplify genomic DNA extracted from single juveniles or females of any of the populations tested either from Spain or Japan. In silico analyses performed with the recently published complete genome of M. incognita, indicated that the MVC marker is not correlated to a MVC or to any eukaryotic organism but to several betaproteobacteria genus from the family Comamonadaceae.     

Evolution of Qol resistance in <Emphasis Type="Italic">Plasmopara viticola</Emphasis> oospores

QoI resistance in P. viticola was first detected in France and Italy in 1999. Molecular and biological assays have been carried out since 2000 in order to provide reliable methods of detecting and quantifying resistance. Oospores were collected in vineyards located in northern and southern Italy. QoI resistance was evaluated by the germination rate of oospores on azoxystrobin amended medium and the frequency of mutant alleles in the DNA extracted from oospores. Both methods correlated to each other and were used side by side to test QoI resistance. Due to the spontaneous occurrence of the G143A mutation in wild type populations and the immigration from surrounding vineyards, resistance frequencies up to 10% were found in samples collected from vineyards never treated with QoIs. Particularly high values, about 90%, were associated with the application of five to six QoI treatments within the same season, while lower percentages, about 30%, were detected in vineyards treated with QoI used in mixture with fungicides belonging to a different resistance group. A progressive decrease of resistance frequency was observed when QoI applications were reduced in number or completely suspended for at least one season. Therefore, a full recovery of sensitivity may be achieved even in vineyards characterized by high levels of resistance, if particular care is taken during disease control by using QoIs only in mixtures and reducing the number of QoI treatments.     

Allelic variation of the ACCase gene and response to ACCase-inhibiting herbicides in pinoxaden-resistant Lolium spp

BACKGROUND: The repeated use of acetyl‐coenzyme A carboxylase (ACCase) inhibiting herbicides to control grass weeds has selected for resistance in Lolium spp. populations in Italy. The efficacy of pinoxaden, a recently marketed phenylpyrazoline herbicide, is of concern where resistance to ACCase inhibitors has already been ascertained. ACCase mutations associated with pinoxaden resistance were investigated, and the cross‐resistance pattern to clodinafop, haloxyfop, sethoxydim, clethodim and pinoxaden was established on homo/heterozygous plants for four mutant ACCase alleles. RESULTS: Seven different mutant ACCase alleles (1781‐Leu, 1999‐Leu, 2041‐Asn, 2041‐Val, 2078‐Gly, 2088‐Arg and 2096‐Ala) and 13 combinations with two types of mutation were detected in the pinoxaden‐resistant plants. The 1781‐Leu allele appears to confer a dominant resistance to pinoxaden, clodinafop, haloxyfop, sethoxydim and clethodim at 60 g AI ha^?1. The 2041‐Asn and 2041‐Val alleles are associated with dominant or partially dominant resistance to FOPs, no substantial resistance to DIMs and a moderate resistance to pinoxaden. The 2088‐Arg allele endows a partially dominant resistance to clodinafop, sethoxydim and most likely to pinoxaden. In addition, non‐target‐site resistance mechanisms seem to be involved in pinoxaden resistance. CONCLUSION: Almost all the ACCase mutations selected in the field by other ACCase inhibitors are likely to confer resistance to pinoxaden. Although pinoxaden is sometimes able to control FOP‐resistant populations, it should not be considered as a sustainable ACCase resistance management tool. The presence of non‐ACCase‐based resistance mechanisms that could confer resistance to herbicides with different modes of action further complicates the resistance management strategies. Copyright © 2011 Society of Chemical Industry     

Arboreal composition changes following white-tailed deer restoration to urban park forests without off-trail park visitor trampling

Human trampling destroys seedlings and saplings without regard to species in urban park forests and the addition of deer browsing compounds the losses. The unexamined research question is: what is the effect of white deer browsing in the absence of human trampling? Radnor Lake State Natural Area, Nashville, TN, USA has been protected from off-pathway human transit since 1973 and white-tailed deer (Odocoileus virginianus Zimmerman) were restored to the Natural Area in 1980. From 1976 to 2007, a plot with tagged trees in the mesic slope forest showed the tree population for 16 species decreased, two remained stable, and one increased. The pattern of increase for sugar maple (Acer saccharum Marsh) was 57 new trees added but 46 trees were lost, which appears as a population increase from 1976 to 1996 and a decrease in 2007. In all five forest communities, the total tree stems per ha declined from 1974 to 2008. During the period 1994–2008, O. virginianus over browsing decimated the seedling population of all species and caused the total for stems per ha for saplings to become smaller than the total stems per ha for trees in each community except the ravine forest, which had the greatest loss of trees. The only consistent change in trees across the five communities when comparing 1974–2008 was the significant tree importance value increase for A. saccharum. The conflicting significant changes for major species, other than A. saccharum, across the Natural Area forest communities informs management for other urban park forests—browsing by O. virginianus results in increased numbers for trees and saplings in the communities the species are well adapted to grow and reproduce in and fewer trees and saplings in the communities with environmental conditions that are not well suited to the species.     

Ketamine-induced loss of phenotype of fast-spiking interneurons is mediated by NADPH-oxidase

Abuse of the dissociative anesthetic ketamine can lead to a syndrome indistinguishable from schizophrenia. In animals, repetitive exposure to this N-methyl-d-aspartate-receptor antagonist induces the dysfunction of a subset of cortical fast-spiking inhibitory interneurons, with loss of expression of parvalbumin and the gamma-aminobutyric acid-producing enzyme GAD67. We show here that exposure of mice to ketamine induced a persistent increase in brain superoxide due to activation in neurons of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Decreasing superoxide production prevented the effects of ketamine on inhibitory interneurons in the prefrontal cortex. These results suggest that NADPH oxidase may represent a novel target for the treatment of ketamine-induced psychosis.     

Synaptic pruning by microglia is necessary for normal brain development

Microglia are highly motile phagocytic cells that infiltrate and take up residence in the developing brain, where they are thought to provide a surveillance and scavenging function. However, although microglia have been shown to engulf and clear damaged cellular debris after brain insult, it remains less clear what role microglia play in the uninjured brain. Here, we show that microglia actively engulf synaptic material and play a major role in synaptic pruning during postnatal development in mice. These findings link microglia surveillance to synaptic maturation and suggest that deficits in microglia function may contribute to synaptic abnormalities seen in some neurodevelopmental disorders.     

Changes in water-soluble vitamins and antioxidant capacity of fruit juice-milk beverages as affected by high-intensity pulsed electric fields (HIPEF) or heat during chilled storage

The effect of high-intensity pulsed electric fields (HIPEF) or thermal processes and refrigerated storage on water-soluble vitamins and antioxidant capacity of beverages containing fruit juices and whole (FJ-WM) or skim milk (FJ-SM) was assessed. Peroxidase (POD) and lipoxygenase (LOX) inactivation as well as color changes were also studied. High vitamin C retention was observed in HIPEF and thermally treated beverages, but a significant depletion of the vitamin during storage occurred, which was correlated with antioxidant capacity. HIPEF treatment did not affect the concentration of group B vitamins, which also remained constant over time, but thermally treated beverages showed lower riboflavin (vitamin B2) concentration. With regard to enzyme activity, thermal processing was more effective than HIPEF on POD and LOX inactivation. The color of the beverages was maintained after HIPEF processing and during storage. Consequently, HIPEF processing could be a feasible technology to attain beverages with fruit juices and milk with high vitamin content and antioxidant potential.     

Radial growth patterns of dominant trees in two old-growth forests in eastern Fennoscandia

We investigated the characteristics and variability of radial growth patterns and the occurrence of growth releases in dominant trees in two old-growth forests in eastern Finland, one dominated by Picea abies and the other by Pinus sylvestris. The dominant trees exhibited high variation in radial growth patterns suggesting that the trees had experienced very different growing conditions and competitive situations during their lifespans. Based on visual evaluation, five types of radial growth patterns were distinguished: descending, even, unimodal (one peak in the growth rate), bimodal (two peaks in the growth rate with an intermediate depression) and fuzzy (no clear pattern). One or more growth releases were detected in 18% of the sampled Picea and in 21% of the Pinus trees. In both the Picea- and the Pinus-dominated sites, the temporal distribution of growth releases was relatively even, except for a moderate peak in 1855–1860. This suggests that small-scale disturbances have been the predominant disturbance mode in both sites during the last 150 years. We conclude that the detected variability in radial growth patterns likely reflects the overall small-scale heterogeneity of structure and developmental processes that are typical of old-growth forests.