Enhancing bacterial survival through phenotypic heterogeneity

What are the benefits of phenotypic heterogeneity? The ability of bacterial populations to develop phenotypically heterogeneous subpopulations has been recognized for decades. A recent study found that genetic hallmarks of phenotypic heterogeneity are ubiquitous among bacterial species of the intestinal microbiota, underscoring that this is a broadly employed, underappreciated survival strategy for both pathogenic and commensal bacterial species. Phenotypic heterogeneity—functional diversity among genetically identical cells—can permit division of labor and cooperative behaviors or serve as a bet-hedging strategy to help ensure the survival of the population as a whole. Division of labor occurs when biological processes are separated among subpopulations, conferring an overall fitness advantage to the population. For example, the opportunistic pathogen Pseudomonas aeruginosa forms multiple unique cell types that perform specialized roles in the formation of biofilm. Some cells contribute to biofilm extracellular matrix production and initiate biofilm development, while others exhibit surface motility and allow biofilm expansion. In the bet-hedging strategy, incorporating phenotypic variants into a population increases the likelihood that some members will survive a stress. In settings where environmental changes are rapid and stark, phenotypic heterogeneity helps ensure the survival of the population at the expense of individuals not well suited to the current environment, which are selected against and lost. This strategy is advantageous over traditional sense-and-respond mechanisms, which require an adaptation time that may be insufficient in the face of sudden or severe environmental changes. Mechanisms of phenotypic heterogeneity may be particularly important in the context of disease, as these mechanisms are more common in host-associated bacteria than in aquatic or terrestrial species

SUE: A Special Purpose Computer for Spin Glass Models

The use of last generation Programmable Electronic Components makes possible the construction of very powerful and competitive special purpose computers. We have designed, constructed and tested a three-dimensional Spin Glass model dedicated machine, which consists of 12 identical boards. Each single board can simulate 8 different systems, updating all the systems at every clock cycle. The update speed of the whole machine is 217ps/spin with 48 MHz clock frequency. A device devoted to fast random number generation has been developed and included in every board. The on-board reprogrammability permits us to change easily the lattice size, or even the update algorithm or the action. We present here a detailed description of the machine and the first runs using the Heat Bath algorithm.Comment: Submitted to Computer Physics Communications, 19 pages, 5 figures, references adde

Blood parasites in endangered wildlife - Trypanosomes discovered during a survey of haemoprotozoa from the Tasmanian devil

The impact of emerging infectious diseases is increasingly recognised as a major threat to wildlife. Wild populations of the endangered Tasmanian devil, Sarcophilus harrisii, are experiencing devastating losses from a novel transmissible cancer, devil facial tumour disease (DFTD); however, despite the rapid decline of this species, there is currently no information on the presence of haemoprotozoan parasites. In the present study, 95 Tasmanian devil blood samples were collected from four populations in Tasmania, Australia, which underwent molecular screening to detect four major groups of haemoprotozoa: (i) trypanosomes, (ii) piroplasms, (iii) Hepatozoon, and (iv) haemosporidia. Sequence results revealed Trypanosoma infections in 32/95 individuals. Trypanosoma copemani was identified in 10 Tasmanian devils from three sites and a second Trypanosoma sp. was identified in 22 individuals that were grouped within the poorly described T. cyclops clade. A single blood sample was positive for Babesia sp., which most closely matched Babesia lohae. No other blood protozoan parasite DNA was detected. This study provides the first insight into haemoprotozoa from the Tasmanian devil and the first identification of Trypanosoma and Babesia in this carnivorous marsupial

Gravitino Dark Matter in the CMSSM and Implications for Leptogenesis and the LHC

In the framework of the CMSSM we study the gravitino as the lightest supersymmetric particle and the dominant component of cold dark matter in the Universe. We include both a thermal contribution to its relic abundance from scatterings in the plasma and a non--thermal one from neutralino or stau decays after freeze--out. In general both contributions can be important, although in different regions of the parameter space. We further include constraints from BBN on electromagnetic and hadronic showers, from the CMB blackbody spectrum and from collider and non--collider SUSY searches. The region where the neutralino is the next--to--lightest superpartner is severely constrained by a conservative bound from excessive electromagnetic showers and probably basically excluded by the bound from hadronic showers, while the stau case remains mostly allowed. In both regions the constraint from CMB is often important or even dominant. In the stau case, for the assumed reasonable ranges of soft SUSY breaking parameters, we find regions where the gravitino abundance is in agreement with the range inferred from CMB studies, provided that, in many cases, a reheating temperature \treh is large, \treh\sim10^{9}\gev. On the other side, we find an upper bound \treh\lsim 5\times 10^{9}\gev. Less conservative bounds from BBN or an improvement in measuring the CMB spectrum would provide a dramatic squeeze on the whole scenario, in particular it would strongly disfavor the largest values of \treh\sim 10^{9}\gev. The regions favored by the gravitino dark matter scenario are very different from standard regions corresponding to the neutralino dark matter, and will be partly probed at the LHC.Comment: JHEP version, several improvements and update

Classification of non-indigenous species based on their impacts: Considerations for application in marine management

Assessment of the ecological and economic/societal impacts of the introduction of non-indigenous species (NIS) is one of the primary focus areas of bioinvasion science in terrestrial and aquatic environments, and is considered essential to management. A classification system of NIS, based on the magnitude of their environmental impacts, was recently proposed to assist management. Here, we consider the potential application of this classification scheme to the marine environment, and offer a complementary framework focussing on value sets in order to explicitly address marine management concerns. Since existing data on marine NIS impacts are scarce and successful marine removals are rare, we propose that management of marine NIS adopt a precautionary approach, which not only would emphasise preventing new incursions through pre-border and at-border controls but also should influence the categorisation of impacts. The study of marine invasion impacts requires urgent attention and significant investment, since we lack the luxury of waiting for the knowledge base to be acquired before the window of opportunity closes for feasible management

Leptogenesis through direct inflaton decay to light particles

We present a scenario of nonthermal leptogenesis following supersymmetric hybrid inflation, in the case where inflaton decay to both heavy right handed neutrino and SU(2)_L triplet superfields is kinematically disallowed. Lepton asymmetry is generated through the decay of the inflaton into light particles by the interference of one-loop diagrams with right handed neutrino and SU(2)_L triplet exchange respectively. We require superpotential couplings explicitly violating a U(1) R-symmetry and R-parity. However, the broken R-parity need not have currently observable low-energy signatures. Also, the lightest sparticle can be stable. Some R-parity violating slepton decays may, though, be detectable in the future colliders. We take into account the constraints from neutrino masses and mixing and the preservation of the primordial lepton asymmetry.Comment: 11 pages including 3 figures, uses Revtex, minor corrections, references adde

Search For Trapped Antihydrogen

We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.Comment: 12 pages, 7 figure

Diversity and patterns of marine non‐native species in the archipelagos of Macaronesia

Aims The present study is the first attempt to grasp the scale and richness of marine biological invasions in Macaronesia. We pioneered a comprehensive non-native species (NNS), inventory in the region to determine their diversity patterns and native distribution origins. NNS were defined here as the result of both introductions and range expansions. We also used statistical modelling to examine relationships among NNS richness, anthropogenic activities, demographic and geographical variables across Macaronesia. Location Macaronesia. Methods A comprehensive literature search was conducted for marine NNS records in Macaronesia, registering the first record's location and year from 1884 to 2020. We used univariate and multivariate analyses to evaluate differences and similarities in community composition. By applying a Generalized Linear Model (GLM), we tested hypotheses regarding NNS richness as a function of anthropogenic activities, demographic and geographical variables. Results A total of 144 marine non-native species (NNS) were recorded for the whole of Macaronesia. The highest NNS richness was registered in the Canary Islands (76 NNS), followed by the Azores (66 NNS), Madeira (59 NNS) and finally Cabo Verde (18 NNS). Some differences amongst archipelagos were observed, such as the high number of non-native macroalgae in the Azores, fishes in the Canary Islands and tunicates in Cabo Verde. Overall, macroalgae, tunicates and bryozoans were the predominant taxonomic groups in the Macaronesian archipelagos. Madeira and Canary Islands were the archipelagos with more similarity in marine NNS, and Cabo Verde the most divergent. Finally, GLM suggested that non-native richness patterns across Macaronesia were dependent on the considered archipelago and strongly affected by (1) minimum distance to the mainland, (2) the total number of ports and marinas and (3) total marinas area (km2). Conclusions The model results and NNS listing in the present study will likely raise the awareness and response regarding marine NNS in the whole Macaronesia region, serving as a baseline for future research as well as implementing and enforcing regulations related to the introduction of marine NNS in oceanic islands

Identification of New Wheat Genes for Durable Resistance of Adult Plants to Yellow Rust (Puccinia striiformis Westend. f. sp. Ericks)

Yellow rust is a wheat disease caused by Puccinia striiformis, this pathogen causes economic losses in susceptible materials, which represent up to 70% of wheat varieties. Currently, the incorporation of genetic resistance through molecular tools, is a process used in the generation of new varieties resistant to this pathogen. A strategy employed to identify genes involved in the resistance to yellow rust is to screen differential EST obtained by suppressive subtractive hybridization. In this research, cDNA was extracted from healthy and inoculated plants from the resistant line V-26 from INIFAP. A set of 200 differentially expressed EST were cloned and sequenced, and 31 of them were selected for expression profile analysis by RT-PCR; additionally, with the aim of validate RT-PCR results, five genes were selected for RT-qPCR analysis in genotypes inoculated by P. striiformis. The results showed high levels of expression of selected genes in genotypes classified as resistant in the field conditions (21, 143, 230, 242, 261 and 277), while in the susceptible genotype 16, few genes were induced by the rust. Expression profiles confirmed significant differences between resistant and susceptible lines