Donated human milk as a determinant factor for the gut bifidobacterial ecology in premature babies

Correct establishment of the gut microbiome is compromised in premature babies, with Bifidobacterium being one of the most affected genera. Prematurity often entails the inability to successfully breastfeed, therefore requiring the implementation of other feeding modes; breast milk expression from a donor mother is the recommended option when their own mother’s milk is not available. Some studies showed different gut microbial profiles in premature infants fed with breast milk and donor human milk, however, it is not known how this affects the species composition of the genus Bifidobacterium. The objective of this study was to assess the effect of donated human milk on shaping the gut bifidobacterial populations of premature babies during the first three months of life. We analyzed the gut bifidobacterial communities of 42 premature babies fed with human donor milk or own-mother milk by the 16S rRNA-23S rRNA internal transcriber spaces (ITS) region sequencing and q-PCR. Moreover, metabolic activity was assessed by gas chromatography. We observed a specific bifidobacterial profile based on feeding type, with higher bifidobacterial diversity in the human donor milk group. Differences in specific Bifidobacterium species composition may contribute to the development of specific new strategies or treatments aimed at mimicking the impact of own-mother milk feeding in neonatal units

Dynamics of Collapse of flexible Polyelectrolytes and Polyampholytes

We provide a theory for the dynamics of collapse of strongly charged polyelectrolytes (PEs) and flexible polyampholytes (PAs) using Langevin equation. After the initial stage, in which counterions condense onto PE, the mechanism of approach to the globular state is similar for PE and PA. In both instances, metastable pearl-necklace structures form in characteristic time scale that is proportional to N^{4/5} where N is the number of monomers. The late stage of collapse occurs by merger of clusters with the largest one growing at the expense of smaller ones (Lifshitz- Slyozov mechanism). The time scale for this process T_{COLL} N. Simulations are used to support the proposed collapse mechanism for PA and PE.Comment: 14 pages, 2 figure

DNA condensation and redissolution: Interaction between overcharged DNA molecules

The effective DNA-DNA interaction force is calculated by computer simulations with explicit tetravalent counterions and monovalent salt. For overcharged DNA molecules, the interaction force shows a double-minimum structure. The positions and depths of these minima are regulated by the counterion density in the bulk. Using two-dimensional lattice sum and free energy perturbation theories, the coexisting phases for DNA bundles are calculated. A DNA-condensation and redissolution transition and a stable mesocrystal with an intermediate lattice constant for high counterion concentration are obtained.Comment: 26 pages, 10 figure

Readiness Potential in Parkinson's Disease: Effects of L-Dopa Therapy and Brain Transplants

Accurate local positioning systems usually use a network of anchor nodes at known locations to track mobile nodes based on the measurement of the time of arrival (TOA) at anchor nodes of beacon signals transmitted by the mobile nodes. To localize the mobile node either TOA processing, where the unknown transmit time is estimated along with the node location, or time difference of arrival (TDOA) processing, where the transmit time is eliminated before estimating the node location, can be used. We show that the position error bound of both these formulations are the same by analyzing the Cramér-Rao lower bound. When processing data collected in field trials, however, we observed that the TOA processing yields better localization accuracy, and explain this behavior using differential geometry-based curvature measures that show that the TDOA cost function has greater degree of non-linearity.T. Sathyan, M. Hedley, M. Mallic

Effect of intrapartum antibiotics prophylaxis on the bifidobacterial establishment within the neonatal gut

Antibiotics are important disruptors of the intestinal microbiota establishment, linked to immune and metabolic alterations. The intrapartum antibiotics prophylaxis (IAP) is a common clinical practice that is present in more than 30% of labours, and is known to negatively affect the gut microbiota composition. However, little is known about how it affects to Bifidobacterium (sub)species level, which is one of the most important intestinal microbial genera early in life. This study presents qualitative and quantitative analyses of the bifidobacterial (sub)species populations in faecal sam-ples, collected at 2, 10, 30 and 90 days of life, from 43 healthy full-term babies, sixteen of them delivered after IAP use. This study uses both 16S rRNA–23S rRNA internal transcribed spacer (ITS) region sequencing and q-PCR techniques for the analyses of the relative proportions and absolute levels, respectively, of the bifidobacterial populations. Our results show that the bifidobacterial populations establishment is affected by the IAP at both quantitative and qualitative levels. This practice can promote higher bifidobacterial diversity and several changes at a compositional level. This study underlines specific targets for developing gut microbiota-based products for favouring a proper bifidobacterial microbiota development when IAP is required

Impact of prematurity and perinatal antibiotics on the developing intestinal microbiota: A functional inference study

The microbial colonization of the neonatal gut provides a critical stimulus for normal maturation and development. This process of early microbiota establishment, known to be affected by several factors, constitutes an important determinant for later health. Methods: We studied the establishment of the microbiota in preterm and full-term infants and the impact of perinatal antibiotics upon this process in premature babies. To this end, 16S rRNA gene sequence-based microbiota assessment was performed at phylum level and functional inference analyses were conducted. Moreover, the levels of the main intestinal microbial metabolites, the short-chain fatty acids (SCFA) acetate, propionate and butyrate, were measured by Gas-Chromatography Flame ionization/Mass spectrometry detection. Results: Prematurity affects microbiota composition at phylum level, leading to increases of Proteobacteria and reduction of other intestinal microorganisms. Perinatal antibiotic use further affected the microbiota of the preterm infant. These changes involved a concomitant alteration in the levels of intestinal SCFA. Moreover, functional inference analyses allowed for identifying metabolic pathways potentially affected by prematurity and perinatal antibiotics use. Conclusion: A deficiency or delay in the establishment of normal microbiota function seems to be present in preterm infants. Perinatal antibiotic use, such as intrapartum prophylaxis, affected the early life microbiota establishment in preterm newborns, which may have consequences for later healt

Lithography-free fabrication of extraordinary transmission plasmonic metasurfaces over large areas employing ultrafast lasers

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordPlasmonic metasurfaces based on the extraordinary optical transmission effect (EOT) can be deliberately designed to efficiently transmit specific spectral bands from the visible to the long-infrared regimes, but can also provide high electric field confinement in regions much smaller than the operation wavelength [1] . Such nano/microphotonic devices (which, as shown in Fig. 1(a) , consist of subwavelength periodically or randomly arranged apertures on ultrathin metallic films) could therefore find applications in important technological fields such as compact multispectral imaging, biosensing, transmissive colour displays, non-linear optics or enhancement of the Raman signal. However, due to their subwavelength nature, fabrication of EOT metasurfaces operating in the visible and infrared spectral regimes is typically conducted through expensive, micro- and nanofabrication techniques carried out in strict cleanroom environments. Therefore, patterning of large areas required for applications currently dominated by conventional optical elements are translated into several fabrication steps and long lithography writing times: procedures that significantly increase the operation cost and energy consumption to a non-acceptable level for most industrial entities.Engineering and Physical Sciences Research Council (EPSRC

Conformational Instability of Rodlike Polyelectrolytes due to Counterion Fluctuations

The effective elasticity of highly charged stiff polyelectrolytes is studied in the presence of counterions, with and without added salt. The rigid polymer conformations may become unstable due to an effective attraction induced by counterion density fluctuations. Instabilities at the longest, or intermediate length scales may signal collapse to globule, or necklace states, respectively. In the presence of added-salt, a generalized electrostatic persistence length is obtained, which has a nontrivial dependence on the Debye screening length. It is also found that the onset of conformational instability is a re-entrant phenomenon as a function of polyelectrolyte length for the unscreened case, and the Debye length or salt concentration for the screened case. This may be relevant in understanding the experimentally observed re-entrant condensation of DNA.Comment: 8 pages, 4 figure