ROLE OF RAB 14 DURING PHAGOSOMAL MATURATION AND ITS IMPLICATION IN THE DROSOPHILA MELANOGASTER IMMUNE RESPONSE

Phagocytosis is a vital component of Drosophila cellular immunity. The sequential interaction of a phagosome with the endocytic compartments entails docking and fusion and requires the role of many RabGTPases. We identified Rab14 as a possible regulator of phagosome maturation in an in vivo screen. Expression studies indicated the presence of Rab14 in hemocytes in both larval and adult stages. To further characterize the role of Rab14 during phagocytosis, a Rab14null mutant was generated. The Rab14 mutant displayed no difference in the phagocytic uptake of E.coli or S.aureus, however the kinetics of phagosome maturation for both microbes was decreased. Cell biology studies indicated delayed acquisition of the late endosomal marker, Rab7 and the lysosomal marker, Spinster, on the S.aureus phagosome. Since recruitment of the early endosomal marker Rab5 was not affected, we concluded Rab14 functions downstream to Rab5 and is essential for efficient Rab7 recruitment on microbial phagosomes. Rab14 itself was recruited during both the early and late phagosomal stages and in accordance with that, it showed colocalization with both Rab5 and Rab7 on endosomes. Rab14 mutants also showed a defect in endosomal maturation, suggesting Rab14 is also essential during endocytosis. Rab14 mutants demonstrated defects in the induction of the specific antimicrobial peptides Cecropin and Defensin in response to S.aureus infection, indicating a possible crosstalk between the cellular and humoral response. Along with that, Rab14 mutants also showed defects in the expression of the Toll ligand Spatzle, in response to infection. Hence we propose Rab14 regulates expression of specific antimicrobial peptides through the cytokine Spatzle. The inefficient cellular and humoral responses result in increased susceptibility of Rab14 mutants to bacterial infection. This could be rescued by hemocyte-specific expression of Rab14, suggesting its role in the hemocytes is essential for the immune response against S. aureus. Our study identifying a role for Rab14 during phagosomal maturation gives insight on the pathogenesis of M.tuberculosis, a pathogen which manipulates Rab14 to subvert phagosome maturation. Moreover it identifies Rab14 function during cellular and humoral responses as an integral component of the Drosophila immune response against S.aureus

Alternative feed sources: Effect on gut microbiota, immunity and health of rainbow trout

Shifting from conventional fishmeal- and soymeal-based aquafeed to low-cost, sustainable dietary alternatives is essential for expansion and resilience in aquaculture. Possible alternative feed resources include under-utilised organic wastes from agriculture and households and by-products from forestry. These resources usually have high nutrient content and may contain bioactive compounds (β-glucans, mannans, lignocellulose etc.) that elicit immunomodulatory responses, modulate gut microbiota and thus improve overall wellbeing in cultured fish. This thesis investigated the dietary potential of Neurospora intermedia, Yarrowia lipolytica and cello-oligosaccharides obtained from industrial by-products, municipal side-streams and forest by-products in diets for rainbow trout.  In a 30-day fish trial, N. intermedia was included in the diet by replacing 30% of the fishmeal-based control diet and diets containing fungi were processed with and without pre-conditioning (heat-treatment). The results showed high apparent digestibility coefficient of the N. intermedia diets and a gradual shift in overall gut microbiota, with increased abundance of Lactococcus from day 0 to 30. Preconditioning had no effect on digestibility or gut microbiota. Pre-treated Y. lipolytica yeast biomass in whole (WY) or autolysed (AY) form was incorporated in rainbow trout diets at 2% or 5% level in a 45-day trial. The 5% WY diet resulted in elevated expression of immune-related genes of the complement pathway, membrane receptor pathway, cytokines and adaptive immune pathway. There was a small impact of dietary Y. lipolytica on faecal microbiota in rainbow trout. The bioactivity of cello-oligosaccharides (COS) was examined by feeding rainbow trout diets containing 0-1.5% graded COS in a 45-day trial. Inclusion of 0.5-1.5% COS slightly increased lactic acid bacteria in faeces and marginally modulated gut immunity with respect to expression of complement and toll-like receptors. The COS diets also increased oxidative stress-reducing capacity in the gut and serum of the fish. These results indicate, N. intermedia, Y. lipolytica and COS can be used successfully as potential functional feed or additive for rainbow trout

A Graphical Digital Personal Assistant That Grounds and Learns Autonomously

We present a speech-driven digital personal assistant that is robust despite little or no training data and autonomously improves as it interacts with users. The system is able to establish and build common ground between itself and users by signaling understanding and by learning a mapping via interaction between the words that users actually speak and the system actions. We evaluated our system with real users and found an overall positive response. We further show through objective measures that autonomous learning improves performance in a simple itinerary filling task

Bilateral Variation in the Origin and Course of the Vertebral Artery

Understanding the great vessels of the aortic arch and their variations is important for both the endovascular interventionist and the diagnostic radiologist. An understanding of the variability of the vertebral artery remains most important in angiography and surgical procedures where an incomplete knowledge of anatomy can lead to serious implications. In the present case, a bilateral variation in the origin and course of vertebral artery was observed. The left vertebral artery took origin from the arch of aorta and entered the foramen transversarium of the fourth cervical vertebra. The right vertebral artery took origin from the right subclavian artery close to its origin and entered the foramen transversarium of the third cervical vertebra. The literature on the variations of the artery is studied and its clinical significance and ontogeny is discussed

A new model for the infrared emission of IRAS F10214+4724

We present a new model for the infrared emission of the high redshift hyperluminous infrared galaxy IRAS F10214+4724 which takes into account recent photometric data from Spitzer and Herschel that sample the peak of its spectral energy distribution. We first demonstrate that the combination of the AGN tapered disc and starburst models of Efstathiou and coworkers, while able to give an excellent fit to the average spectrum of type 2 AGN measured by Spitzer, fails to match the spectral energy distribution of IRAS F10214+4724. This is mainly due to the fact that the nuSnu distribution of the galaxy falls very steeply with increasing frequency (a characteristic of heavy absorption by dust) but shows a silicate feature in emission. We propose a model that assumes two components of emission: clouds that are associated with the narrow-line region and a highly obscured starburst. The emission from the clouds must suffer significantly stronger gravitational lensing compared to the emission from the torus to explain the observed spectral energy distribution.Comment: 4 pages, 1 figure, to be published in 'The Spectral Energy Distribution of Galaxies' J. Tuffs \& C.C.Popescu, ed

Lyman-break galaxies at z~5 -I. First significant stellar mass assembly in galaxies that are not simply z~3 LBGs at higher redshift

We determine the ensemble properties of z~5 Lyman break galaxies (LBGs) selected as V-band dropouts to i(AB)<26.3 in the Chandra Deep Field South using their rest-frame UV-to-visible SEDs. By matching the selection and performing the same analysis that has been used for z~3 samples, we show clear differences in the properties of two samples of LBGs which are separated by ~1Gyr in lookback time. We find that z~5 LBGs are typically much younger (<100Myr) and have lower stellar masses (10^9Msol) than their z~3 counterparts. The difference in mass is significant even when considering the presence of an older, underlying population in both samples. Such young and moderately massive systems dominate the luminous z~5 LBG population (>70%), whereas they comprise <30% of LBG samples at z~3. This result is robust under all reasonable modelling assumptions. These intense starbursts appear to be experiencing their first (few) generations of large-scale star formation and are accumulating their first significant stellar mass. Their dominance in luminous LBG samples suggests that z~5 witnesses a period of wide-spread, recent galaxy formation. As such, z~5 LBGs are the likely progenitors of the spheroidal components of present-day massive galaxies. This is supported by their high stellar mass surface densities, their core phase-space densities, as well as the ages of stars in the bulge of our Galaxy and other massive systems. Their high star formation rates per unit area suggest that these systems host outflows or winds that enrich the intra- and inter-galactic media with metals. Their estimated young ages are consistent with inefficient metal-mixing on galaxy-wide scales. Therefore these galaxies may contain a significant fraction of metal-free stars as has been proposed for z~3 LBGs (Jimenez & Haiman 2006). [Abridged]Comment: Accepted for publication in MNRAS. 21 pages, 9 postscript figures. For a PDF file with high resolution figures, see http://www-astro.physics.ox.ac.uk/~averma

Interstitial pregnancy: a case report

Interstitial pregnancy is a life-threatening event. Strong clinical suspicion and prompt action can reduce maternal morbidity and mortality. Specific ultrasound features point towards the diagnosis. Various treatment modalities are available as there is no consensus for a treatment of choice. The management option depends upon the general condition of the patient and also on fact whether the ectopic pregnancy has ruptured or not. Here we present a case of an unruptured interstitial pregnancy

Posterior reversible encephalopathy syndrome: a case report

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic syndrome that is characterised by neurological symptoms and radiological features. The symptoms include vomiting, headache, seizures, variable loss of eyesight and loss of consciousness. Imaging studies show white mater abnormalities and edema. Management includes control of blood pressure and prevention of seizures along with timely delivery. Some patients might require ICU admission and a multidisciplinary team management. The condition has a good prognosis if timely management is instituted. Here we present a case report on PRES syndrome.