Jasmonic acid signalling mediates resistance of the wild tobacco Nicotiana attenuata to its native Fusarium,but not Alternaria,fungal pathogens

We recently characterized a highly dynamic fungal disease outbreak in native populations of Nicotiana attenuata in the southwestern United States. Here, we explore how phytohormone signalling contributes to the observed disease dynamics. Single inoculation with three native Fusarium and Alternaria fungal pathogens, isolated from diseased plants growing in native populations, resulted in disease symptoms characteristic for each pathogen species. While Alternaria sp.‐infected plants displayed fewer symptoms and recovered, Fusarium spp.‐infected plants became chlorotic and frequently spontaneously wilted. Jasmonic acid (JA) and salicylic acid (SA) levels were differentially induced after Fusarium or Alternaria infection. Transgenic N. attenuata lines silenced in JA production or JA conjugation to isoleucine (JA‐Ile), but not in JA perception, were highly susceptible to infection by F. brachygibbosum Utah 4, indicating that products derived from the JA‐Ile biosynthetic pathway, but not their perception, is associated with increased Fusarium resistance. Infection assays using ov‐nahG plants which were silenced in pathogen‐induced SA accumulations revealed that SA may increase N. attenuata's resistance to Fusarium infection but not to Alternaria. Taken together, we propose that the dynamics of fungal disease symptoms among plants in native populations may be explained by a complex interplay of phytohormone responses to attack by multiple pathogens.     

No relationship between canalization and developmental stability of the skull in a natural population of Mastomys natalensis (Rodentia: Muridae)

The aim of the present work was to investigate the relationship between canalization and developmental stability under varying environmental conditions. Three different cohorts of Mastomys natalensis (Rodentia, Muridae), displaying different growth trajectories, were analysed by means of geometric morphometrics. A set of 23 landmarks was digitalized on the dorsal skull of 292 specimens from Morogoro (Tanzania). Patterns of among‐ and within‐individual (measured as fluctuating asymmetry, FA) variation were assessed and compared among and within the three groups to test for the presence of a common mechanism between canalization and developmental stability. Results showed that there was no congruence between canalization and developmental stability: (1) levels of FA and among‐individual variation varied in a discordant fashion, (2) no correspondence between the variance–covariance matrix of among‐ and within individual variation was found, and (3) environmental effects were able to alter the covariance structure of among‐individual variation leaving patterns associated with fluctuating asymmetry unaffected. These findings support the view of multiple mechanisms underlying developmental buffering of shape variation. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 207–216.     

LACK of DNA SYNTHESIS INHIBITORY ACTIVITY IN an IMMUNOSUPPRESSOR OBTAINED FROM SPLEEN

A tissue extract derived from bovine spleen which is an immunosuppressor in vivo inhibits the incorporation of the two DNA pyrimidine nucleosides but does not inhibit the incorporation of purine nucleosides. the results indicate that the immunosuppressive action of the spleen extract is not mediated via inhibition of cell division.     

Quantifying uncertainty from large-scale model predictions of forest carbon dynamics

Linking environmental computer simulation models and geographic information systems (GIS) is now a common practice to scale up simulations of complex ecosystem processes for decision support. Unfortunately, several important issues of upscaling using GIS are rarely considered; in particular scale dependency of models, availability of input data, support of input and validation data, and uncertainty in prediction including error propagation from the GIS. We linked the biogeochemical Forest‐DNDC model to a GIS database to predict growth of Eucalyptus globulus plantations at two different scales (～0.045 ha plot^?1 scale and ～100 ha grid^?1 scale) across Victoria, in south‐eastern Australia. Results showed that Forest‐DNDC was not scale dependent across the range of scales investigated. Reduced availability of input data at the larger scale may introduce severe prediction errors, but did not require adjustment of the model in this study. Differences in the support of input and validation data led to an underestimation of predictive precision but an overestimation of prediction accuracy. Increasing data support, produced a high level of prediction accuracy (^?e%), but a medium level of predictive precision (r²=0.474, ME=0.318) after statistical validation. GIS error contribution could be detected but was not readily or reliably quantified. In a regional case study for 2653 ha of E. globulus plantations, the linked model GIS system estimated a total standing biomass of 95 260 t C for mid‐2003 and a net CO₂ balance of ?45 671 t CO₂‐C yr^?1 for the entire year of 2002. This study showed that regional predictions of forest growth and carbon sequestration can be produced with greater confidence after a comprehensive assessment of upscaling issues.     

Sequential colonization by river periphyton analysed by microscopy and molecular fingerprinting

1. An artificial glass substratum was incubated in the River Danube for a period of 28 days in order to detect the sequential colonization of microorganisms.
2. Light and fluorescent microscopy showed that microalgae and the picoalgal fraction on the slides increased rapidly over the first 2 weeks of colonization. Diatoms were numerically the most abundant component of the periphyton and their species richness and diversity increased rapidly in the early phase of colonization whereas diversity subsequently increased moderately.
3. Evenness of the diatom community was initially high, lower in the intermediate phase and again higher later on. Succession involving early, intermediate and late colonizer species was observed. Community composition during the first 5 days of colonization was very different from later stages whereas there were only minor changes subsequently.
4. Molecular community analysis by means of terminal restriction fragment length polymorphism analysis of PCR amplified 16S rRNA and 18S rRNA genes pointed to even larger differences between the composition of samples obtained early and late in the period.
5. The number of 18S rRNA and 16S rRNA terminal restriction fragments (T-RF-s) was variable over the colonization period and the fragment patterns of both the bacterial and eukaryotic portion of the microbial community were variable, with most T-RF-s unique to a single sample, suggesting a wide diversity and dynamic properties of periphytic organisms.     

Occurrence of Beta-Lactamases in Colistin-Resistant Enterobacterales Strains in Poland – a Pilot Study

Sixty-five colistin-resistant Enterobacterales isolates recovered from different clinical specimens were analyzed. The strains were collected in 12 hospitals all over Poland within a period of nine months. Strains were analyzed for eight genes from the mcr family. The presence of mcr-1 gene was detected in three Escherichia coli strains. The 45/65 isolates were identified as ESBL producers. CTX-M-1-like enzymes were the most common ESBLs (n = 40). One E. coli and seven Klebsiella pneumoniae strains produced carbapenemases, with the NDM being produced by five isolates. Among all the strains tested, four and five were resistant to new drugs meropenem/vaborbactam and ceftazidime/avibactam, respectively.     

YOU CAN USE MY NAME; YOU DON'T HAVE TO STEAL MY STORY – A CRITIQUE OF ANONYMITY IN INDIGENOUS STUDIES

Our claim in this paper is that not being identified as the data source might cause harm to a person or group. Therefore, in some cases the default of anonymisation should be replaced by a careful deliberation, together with research subjects, of how to handle the issues of identification and confidentiality. Our prime example in this article is community participatory research and similar endeavours on indigenous groups. The theme, content and aim of the research, and the question of how to handle property rights and ownership of research results, as well as who should be in charge of the research process, including the process of creating anonymity, should all be answered, before anonymity is accepted.     

The After-Effect of Water Stress on Transpiration Rate and Changes in Abscisic Acid Content of Young Wheat Plants

Young wheat plants (Triticum aestivum L. cv. Weibulls Starke II) were exposed to water stress for 1, 2 or 3 hours by cooling the roots. The plants were subjected to a constant water stress during the stress periods. By this treatment the leaf water potential was lowered from ?6.5 to ?11.5 bars. Leaf water potential, transpiration rate and abscisic acid content were determined during the stress periods and during the recovery. The water stressed plants showed an after-effect on transpiration rate lasting for between 10 and 24 hours depending on the duration of the stress. The amount of water stress in the stressed plants compared with the controls is defined as the difference in leaf water potential between the controls and the stressed plants during the stress period integrated over time. The amount of after-affect on transpiration is analogously defined as the difference in transpiration rate between the controls and the stressed plants during the recovery period integrated over time. There was a linear relationship between the amount of water stress and the amount of after-effect on transpiration of the leaves. The abscisic acid content of the leaves increased between 3.0 and 4.5 times the original content depending on the duration of the stress. However, during the recovery the abscisic acid content reattained the pre-stress level within 3 hours for all three stress periods. There was thus no direct relationship between the after-effect and the abscisic acid content of the leaf.