Comment on "Late Mousterian persistence near the Arctic Circle"

Slimak et al. (Reports, 13 May 2011, p. 841) reanalyzed the lithic assemblage from the northern site of Byzovaya (Russia) and concluded that it was Mousterian and produced by Neandertals. The previous interpretation of this assemblage as falling within Early Upper Paleolithic variability remains the most parsimonious explanation; pending additional fossil discoveries, there is no evidence supporting the occurrence of Neandertals at these high latitudes.     

Comment on "Productivity is a poor predictor of plant species richness"

Adler et al. (Reports, 23 September 2011, p. 1750) analyzed the standardized sampling data from 48 herbaceous-dominated plant communities and concluded that "Productivity is a poor predictor of plant species richness" at fine-scale. However, their method was biased toward site-number-dominated plant communities. They also failed to provide enough data for regional analysis and detailed information for within-site analysis.     

Antagonistic effect of indigenous skin bacteria of brook charr (Salvelinus fontinalis) against Flavobacterium columnare and F. psychrophilum

Industrial fish production exposes fish to potentially stressful conditions, which in turn may induce infections by opportunistic pathogens. Probiotics appear to be a promising way to prevent opportunistic infections in aquaculture. In this study, we tested the inhibitory potential of endogenous bacterial communities found in the mucus of brook charr (Salvelinus fontinalis) against two major pathogens Flavobacterium columnare and Flavobacterium psychrophilum. Nine bacterial strains were isolated from brook charr skin mucus and tested for potential antagonistic activity. Results from both agar diffusion assays and broth co-culture assays showed the presence of antagonism. We identified seven bacterial strains, collected from unstressed fish, which exerted strong antagonism against F. psychrophilum and/or F. columnare. These strains were mixed and used to treat columnaris disease in an in vivo experiment in which four distinct fish families were tested. This treatment resulted in a decrease of mortality (54-86%) across fish families indicating that candidates from the host microbiota are potentially suitable for probiotic development. This would allow for the efficient (ability to adhere and colonize the host mucus) and durable management (antagonistic effect against pathogens which would be harmless for the host and safe for its environment) of opportunistic diseases in aquaculture.     

Infectiousness of pigs infected by the Porcine Reproductive and Respiratory Syndrome virus (PRRSV) is time-dependent

The time-dependent transmission rate of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and the correlation between infectiousness, virological parameters and antibody responses of the infected pigs were studied in experimental conditions. Seven successive transmission trials involving a total of 77 specific pathogen-free piglets were carried out from 7 to 63 days post-inoculation (dpi). A semi-quantitative real time RT-PCR was developed to assess the evolution of the viral genome load in blood and nasal swabs from inoculated and contact pigs, with time. Virus genome in blood was detectable in inoculated pigs from 7 to 77 dpi, whereas viral genome shedding was detectable from nasal swabs from 2 to 48 dpi. The infectiousness of inoculated pigs, assessed from the frequency of occurrence of infected pigs in susceptible groups in each contact trial, increased from 7 to 14 dpi and then decreased slowly until 42 dpi (3, 7, 2, 1 and 0 pigs infected at 7, 14, 21, 28 and 42 dpi, respectively). These data were used to model the time-dependent infectiousness by a lognormal-like function with a latency period of 1 day and led to an estimated basic reproduction ratio, R₀ of 2.6 [1.8, 3.3]. The evolution of infectiousness was mainly correlated with the time-course of viral genome load in the blood whereas the decrease of infectiousness was strongly related to the increase in total antibodies.     

Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes

Summary Biotic and abiotic stresses cause significant yield losses in legumes and can significantly affect their productivity. Biotechnology tools such as marker-assisted breeding, tissue culture, in vitro mutagenesis and genetic transformation can contribute to solve or reduce some of these constraints. However, only limited success has been achieved so far. The emergence of “omic” technologies and the establishment of model legume plants such as Medicago truncatula and Lotus japonicus are promising strategies for understanding the molecular genetic basis of stress resistance, which is an important bottleneck for molecular breeding. Understanding the mechanisms that regulate the expression of stress-related genes is a fundamental issue in plant biology and will be necessary for the genetic improvement of legumes. In this review, we describe the current status of biotechnology approaches in relation to biotic and abiotic stresses in legumes and how these useful tools could be used to improve resistance to important constraints affecting legume crops.     

Impact of season and grafter skill on nucleus retention and pearl oyster mortality rate in Pinctada margaritifera aquaculture

The mollusc Pinctada margaritifera is the top economic aquaculture species in French Polynesia (export value) and forms the basis of the black pearl industry. Mass production of this unique gem, produced by a living organism, relies on a surgical operation requiring tissue from a donor pearl oyster to be grafted, together with a nucleus made of shell, into the gonad of a receiving pearl oyster. This technique is performed by expert grafters, whose work constitutes the first step influencing pearl farm production yield. This study makes the first report of effects mediated by individual grafters and by the season of grafting on three rates scored at 45 days post operation: nucleus retention, nucleus rejection and pearl oyster mortality. These results were obtained in a very large scale grafting experiment, designed and conducted in a single culture site in the atoll of Arutua (Tuamotu Archipelago) and involving a total of 52,910 grafts performed by ten professional grafters, during two contrasting seasons: autumn (four grafting experiments) and spring (three grafting experiments). Statistical analysis using linear mixed-effect model for both univariate and multivariate analysis was performed. The results show a very highly significant season effect (p < 0.001), with a higher rate of nucleus retention in autumn than spring: 91.1 versus 79.4 %, respectively. A very highly significant season effect was also recorded for nucleus rejection rate (p < 0.001), which was greater in spring than in autumn: 12.6 versus 7.7 %. Oyster mortality rate was up to six times higher in spring than in autumn (p < 0.001). Within the two seasons, there was no significant difference between the grafting experiments for any of the three variables, adding robustness to the inter-season results. Taking into account this seasonal variation effect, grafter skill had a significant impact on the three variables (p < 0.001), making it possible to rank grafters from most to least efficient. Aside from skill differences between grafters, grafting in autumn may significantly increase graft success. Water temperature and its indirect consequences could be one of the most important environmental factors implicated in overall efficiency. These findings may help the potential development of an annual grafting schedule according to season/ lagoon temperature as a way to maximize production yield for the black-lipped pearl oyster industry in French Polynesia.     

Intraguild predation between an exotic and a native coccinellid in Argentina: the role of prey density

Journal of Pest Science - Harmonia axyridis Pallas is a generalist predator native to Asia. It has been released both for classical and neoclassical biological control programs worldwide. Its...     

Surgical endodontics in dogs: a review

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage--a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst--a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez--cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwigs epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.