Inflationary Perturbations in Palatini Generalised Gravity

We examine the generation of primordial perturbations during an inflationary epoch in generalised theories of gravity when the equations of motion are derived using the Palatini variational principle. Both f(R) and Scalar-Tensor theories are considered and we compare our results with those obtained under the conventional metric formalism. Non-linear generalisations of the action lead to different theories under the two variational choices and we obtain distinct results for scalar and tensor spectral indices and their ratio. We find the following general result; inflation driven solely by f(R) modifications alone do not result in suitable curvature perturbations whilst Scalar-Tensor theories generate nearly scalar invariant curvature perturbations but no tensor modes.Comment: 9 page

Biomimetic hydroxyapatite nanocrystals are an active carrier for Salmonella bacteriophages

open access articlePurpose: The use of bacteriophages represents a valid alternative to conventional antimicrobial treatments, overcoming the widespread bacterial antibiotic resistance phenomenon. In this work, we evaluated whether biomimetic hydroxyapatite (HA) nanocrystals are able to enhance some properties of bacteriophages. The final goal of this study was to demonstrate that biomimetic HA nanocrystals can be used for bacteriophage delivery in the context of bacterial infections, and contribute – at the same time – to enhance some of the biological properties of the same bacteriophages such as stability, preservation, antimicrobial activity, and so on. Materials and methods: Phage isolation and characterization were carried out by using Mitomycin C and following double-layer agar technique. The biomimetic HA water suspension was synthesized in order to obtain nanocrystals with plate-like morphology and nanometric dimensions. The interaction of phages with the HA was investigated by dynamic light scattering and Zeta potential analyses. The cytotoxicity and intracellular killing activities of the phage–HA complex were evaluated in human hepatocellular carcinoma HepG2 cells. The bacterial inhibition capacity of the complex was assessed on chicken minced meat samples infected with Salmonella Rissen. Results: Our data highlighted that the biomimetic HA nanocrystal–bacteriophage complex was more stable and more effective than phages alone in all tested experimental conditions. Conclusion: Our results evidenced the important contribution of biomimetic HA nanocrystals: they act as an excellent carrier for bacteriophage delivery and enhance its biological characteristics. This study confirmed the significant role of the mineral HA when it is complexed with biological entities like bacteriophages, as it has been shown for molecules such as lactoferrin

Whole blood transcriptome analysis in ewes fed with hemp seed supplemented diet

the hemp plant (Cannabis sativa L.) has a long tradition of being used for many di erent purposes such as industry, medicine and nutrition. In particular, because hemp seed (HS) is rich in oil protein and considerable amounts of dietary ber, vitamins and minerals that are particularly suitable also for animal nutrition. Di erent studies have evaluated HS on qualitative and quantitative properties of livestock products but as of today, nobody has investigated the molecular pathway behind HS supplementation in farm animals. Thus, in this study, we will report the rst RNA sequencing of the whole-blood transcriptome of ewes fed either with a controlled diet (CTR, n = 5) or with a diet supplemented with 5% of hemp seed (HSG, n = 5). Applying a false discovery rate (FDR) <0.05 and a log2FC either higher than 0.5 or lower than −0.5, we identi ed 314 di erentially regulated genes in the HS-supplemented group compared to the CTR group. Several genes encoding for di erent subunits belonging to the complex I, II, III, IV and ATP-synthase were up-regulated making oxidative phosphorylation (FDR: 3.05e-19) and thermogenesis (FDR: 2.17e-16) the highest up-regulated pathways in our study. Moreover, we found up-regulation in di erent genes involved in lactose biosyntheses such as GALK1 and PGM1 and, as a result, we observed a statistically higher lactose percentage in the HSG group (p < 0.05). These results indicate that HS supplementation positively a ects the energy production pathway in lactating ewes conferring them also more resistance to adverse climatic conditions such as low temperature. Finally, the higher milk lactose content makes the derived dairy products more pro table

Modified Gravity and Cosmology

In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f(R), general higher-order theories, Horava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Parameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.Comment: 312 pages, 15 figure

Planck 2015 results. XX. Constraints on inflation

We present the implications for cosmic inflation of the Planck measurements of the cosmic microwave background (CMB) anisotropies in both temperature and polarization based on the full Planck survey. The Planck full mission temperature data and a first release of polarization data on large angular scales measure the spectral index of curvature perturbations to be n s = 0.968 ± 0.006 and tightly constrain its scale dependence to dn s /dlnk = −0.003 ± 0.007 when combined with the Planck lensing likelihood. When the high-ℓ polarization data is included, the results are consistent and uncertainties are reduced. The upper bound on the tensor-to-scalar ratio is r 0.002 <0.11 (95% CL), consistent with the B-mode polarization constraint r<0.12 (95% CL) obtained from a joint BICEP2/Keck Array and Planck analysis. These results imply that V(ϕ)∝ϕ 2 and natural inflation are now disfavoured compared to models predicting a smaller tensor-to-scalar ratio, such as R 2 inflation. Three independent methods reconstructing the primordial power spectrum are investigated. The Planck data are consistent with adiabatic primordial perturbations. We investigate inflationary models producing an anisotropic modulation of the primordial curvature power spectrum as well as generalized models of inflation not governed by a scalar field with a canonical kinetic term. The 2015 results are consistent with the 2013 analysis based on the nominal mission data

THE GENOME SEQUENCE OF SOLANUM COMMERSONII DUN., A VALUABLE SOURCE OF RESISTANT GENES FOR POTATO BREEDING

The tetraploid cultivated potato (Solanum tuberosum, 2n=4x=48) is the fourth most important crop for humans. Since the cultivated varieties are derived from a small number of genotypes, potato is characterized by a low genetic variability. Fortunately, it has about 200 wild tuber-bearing relatives that represent an incredible source of genetic variation and a reservoir of useful genes for the development of new varieties with improved resistance, nutrient content and productivity. However, several constrains hamper wild germplasm utilization. Among them, sexual incompatibility between wild and cultivated species and linkage drag make classical breeding methods time-consuming and laborious. In addition, few genomic resources ara available that can help breeders in their work of producing genetic variability and select superior clones. For all these reasons there has been an under-utilization of the potato genetic resources. The objective of this research was to develop new genomic tools that enable the expansion of the existing breeding strategies for an efficient exploitation of potato genetic resources. Nowadays, sequencing technology combined with the availability of the S. tuberosum reference genome allows the characterization of the genetic variations affecting the cultivated potato. However, no genome sequence is available for a wild potato species. Therefore our study was addressed to sequence the genome of one of the most important tuber-bearing species, S. commersonii (2n=2x=24), that possesses several resistances to biotic and abiotic stresses. We de novo sequenced the genome of S. commersonii to 103x coverage using Illumina technology producing a 862 Mb genome. On the basis of sequence homology, 39,290 protein-coding genes were predicted and supported by transcript data and further annotation. We used the orthology and paralogy proteins relationships for the reconstruction of the complete collection of evolutionary histories of all S. commersonii protein-coding genes across a phylogeny of 12 sequenced plants. Interestingly, we discovered 8,578 S. commersonii-specific gene families lacking in S. tuberosum. HMM models and manual curation were used to annotate 2,523 non-redundant NBS-encoding R gene candidates, and comparison analysis with potato R-genes supported the idea that a locus rearrangement occurred during evolution. In order to find out the genetic determinants of S. commersonii resistance to low temperatures and capacity to cold harden, we focused on genes involved in abiotic stress response. Out of roughly 2,800 cold resistance genes, we found that 126 were unique in S. commersonii. To investigate further, a transcriptome analysis by using a custom microarray chip was carried out in two different experimental conditions. This allowed us to detect all the expressed genes involved in cold acclimation and to hypothesize the molecular dinamics at the basis of the different response to low temperature in S. commersonii vs. S. tuberosum. The experimental work carried out in this PhD reports the first genome sequence for a wild relative of the cultivated potato The genome sequence of S. commersonii has substantially increased our understanding on wild potatoes and these information might be used to overcome the limitations due to the low variability of domesticated germplasm. It will also offer the potential of better using wild relatives for potato breeding and evolutionary studies

Salmonella Rissen Φ1: a molecular switch

Introduction: Bacteria develop resistance against phages by losing the phage receptor or reducing its binding specificity or by a temporary change of phage receptor specificity. Here we describe the phage resistance mechanism adopted by S. Rissen which acts through a molecular switch. Material & Methods: Phage was isolated from the S. Rissen strain (RW) and used to select the phage resistant strain RRϕ1+. We evaluate both the differences in bacterial morphology and the genetic variations between the two strains by biochemical and comparative genomic analyses. Results: Biochemical analyses showed that the presence of the phage influences biofilm production, phage resistance and the switch of the O-antigen from smooth to rough, Genomic analysis showed that the sensitive and resistant strains differ by 10 genes. Only the phosphomannomutase_1 and 2 genes, involved in mannose synthesis pathway, showed different expression levels. The SNP of the two genes are located near HTs known to regulate phase variation. We used S rissen to see whether a character under strong selection pressure- such as phage resistance is repeatable. In four independent experiment phage resistance was acquired by the same molecular mechanism. Conclusion: S. rissen uses the same and evolutionary flexible tool (phase variation) to control several characters: biofilm production, phage resistance, and O-antigen structure