Development of a miniaturized nitrate reduction test for the identification of oral bacteria

A miniaturized nitrate reduction test (MNRT) for oral bacteria was developed and its reliability compared with a conventional nitrate reduction test (CNRT). In the MNRT 100 [mu]l aliquots of freshly grown heavy suspension of various oral bacterial species, in physiological saline, were added to equal volumes of 0.1% filter-sterilized KNO3 solution in distilled water in wells of transparent plastic plates. Duplicate plates were incubated aerobically or anaerobically at 35[deg]C for 12-15 h. At the end of the incubation period the test was performed by adding either a trace amount of a non-liquid reagent (mixture of -(+)-tartaric acid, sulfanilic acid and 1-naphthylenediamine dihydrochloride, 10:1:1, wt/wt) or conventional liquid reagents A and B (sulfanilic acid and N,N-dimethyl-1-naphthylamine). In the conventional nitrate reduction test (CNRT), tubes of a basal anaerobic broth were inoculated with the same bacterial species used for MNRT, and the nitrate reduction tests performed after anaerobic incubation of the cultures for 4-6 days. Several hundred anaerobic and facultative bacterial isolates belonging to genera Veillonella, Bacteroides, Fusobacterium, Selenomonas, Actinomyces and Capnocytophaga were characterized by MNRT and CNRT. Analysis of the data showed that MNRT and CNRT systems were comparable. In the MNRT system Veillonella parvula and Selenomonas sputigena were capable of reducing nitrate only under anaerobic conditions. Actinomycetes reduced the nitrates under aerobic and anaerobic conditions, while all black-pigmented Bacteroides, Fusobacterium and Capnocytophaga species did not reduce nitrate. These findings suggest that the MNRT is reliable, rapid and may be conveniently used in clinical or research laboratories with a heavy microbiological work load.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24746/1/0000168.pd

Carbon storage in soils of Southeastern Nigeria under different management practices

<p>Abstract</p> <p>Background</p> <p>Changes in agricultural practices-notably changes in crop varieties, application of fertilizer and manure, rotation and tillage practices-influence how much and at what rate carbon is stored in, or released from, soils. Quantification of the impacts of land use on carbon stocks in sub-Saharan Africa is challenging because of the spatial heterogeneity of soil, climate, management conditions, and due to the lack of data on soil carbon pools of most common agroecosystems. This paper provides data on soil carbon stocks that were collected at 10 sites in southeastern Nigeria to characterize the impact of soil management practices.</p> <p>Results</p> <p>The highest carbon stocks, 7906-9510 gC m^-2, were found at the sites representing natural forest, artificial forest and artificial grassland ecosystems. Continuously cropped and conventionally tilled soils had about 70% lower carbon stock (1978-2822 gC m^-2). Thus, the soil carbon stock in a 45-year old <it>Gmelina </it>forest was 8987 gC m^-2, whereas the parts of this forest, that were cleared and continuously cultivated for 15 years, had 75% lower carbon stock (1978 gC m^-2). The carbon stock of continuously cropped and conventionally tilled soils was also 25% lower than the carbon stock of the soil cultivated by use of conservation tillage.</p> <p>Conclusion</p> <p>Introducing conservation tillage practices may reduce the loss of soil carbon stocks associated with land conversion. However, the positive effect of conservation tillage is not comparable to the negative effect of land conversion, and may not result in significant accumulation of carbon in southeastern Nigeria soils.</p

Abundant Degenerate Miniature Inverted-Repeat Transposable Elements in Genomes of Epichloid Fungal Endophytes of Grasses

Miniature inverted-repeat transposable elements (MITEs) are abundant repeat elements in plant and animal genomes; however, there are few analyses of these elements in fungal genomes. Analysis of the draft genome sequence of the fungal endophyte Epichloë festucae revealed 13 MITE families that make up almost 1% of the E. festucae genome, and relics of putative autonomous parent elements were identified for three families. Sequence and DNA hybridization analyses suggest that at least some of the MITEs identified in the study were active early in the evolution of Epichloë but are not found in closely related genera. Analysis of MITE integration sites showed that these elements have a moderate integration site preference for 5′ genic regions of the E. festucae genome and are particularly enriched near genes for secondary metabolism. Copies of the EFT-3m/Toru element appear to have mediated recombination events that may have abolished synthesis of two fungal alkaloids in different epichloae. This work provides insight into the potential impact of MITEs on epichloae evolution and provides a foundation for analysis in other fungal genomes

Hiding from the Moonlight: Luminosity and Temperature Affect Activity of Asian Nocturnal Primates in a Highly Seasonal Forest

The effect of moonlight and temperature on activity of slow lorises was previously little known and this knowledge might be useful for understanding many aspects of their behavioural ecology, and developing strategies to monitor and protect populations. In this study we aimed to determine if the activity of the pygmy loris (Nycticebus pygmaeus) is affected by ambient temperature and/or moonlight in a mixed deciduous forest. We radio-collared five females and five males in the Seima Protection Forest, Cambodia, in February to May, 2008 and January to March, 2009 and recorded their behaviour at 5 minutes intervals, totalling 2736 observations. We classified each observation as either inactive (sleeping or alert) or active behaviour (travel, feeding, grooming, or others). Moon luminosity (bright/dark) and ambient temperature were recorded for each observation. The response variable, activity, was binary (active or inactive), and a logit link function was used. Ambient temperature alone did not significantly affect mean activity. Although mean activity was significantly affected by moonlight, the interaction between moonlight and temperature was also significant: on bright nights, studied animals were increasingly more active with higher temperature; and on dark nights they were consistently active regardless of temperature. The most plausible explanation is that on bright cold nights the combined risk of being seen and attacked by predators and heat loss outweigh the benefit of active behaviours

Regulating the 1918-19 pandemic: flu, stoicism and the Northcliffe press

Social historians have argued that the reason the 1918–19 ‘Spanish’ influenza left so few traces in public memory is that it was ‘overshadowed’ by the First World War, hence its historiographical characterisation as the ‘forgotten’ pandemic. This paper argues that such an approach tends to overlook the crucial role played by wartime propaganda. Instead, I put emotion words, emotives and metaphors at the heart of my analysis in an attempt to understand the interplay between propaganda and biopolitical discourses that aimed to regulate civilian responses to the pandemic. Drawing on the letters of Wilfred Owen, the diaries of the cultural historian Caroline Playne and the reporting in the Northcliffe press, I argue that the stoicism exhibited by Owen and amplified in the columns of The Times and the Daily Mail is best viewed as a performance, an emotional style that reflected the politicisation of ‘dread’ in war as an emotion with the potential to undermine civilian morale. This was especially the case during the final year of the conflict when war-weariness set in, leading to the stricter policing of negative emotions. As a protean disease that could present as alternately benign and plague-like, the Spanish flu both drew on these discourses and subverted them, disrupting medical efforts to use the dread of foreign pathogens as an instrument of biopower. The result was that, as dread increasingly became attached to influenza, it destabilised medical attempts to regulate the civilian response to the pandemic, undermining Owen’s and the Northcliffe press’s emotives of stoicism

PRODUCTION OF HIGHLY POLARIZED SOLID 3He IN A POMERANCHUK CELL

La meilleure façon de produire du solide 3He fortement polarisé dans une cellule est de solidifier dans un fort champ magnétique du liquide 3He prérefroidi. Cet article est conçu comme une présentation pédagogique de la méthode de Pomeranchuk (solidification adiabatique de 3He liquide) appliquée à ce but.Highly polarized solid 3He in bulk is best produced by solidification, in a magnetic field, of precooled liquid 3He. The paper is a tutorial introduction to the application of the Pomeranchuk method (adiabatic solidification of liquid 3He) for this purpose