Outer Surface Lipoprotein Layer Homeostasis and Gene Regulation in Borrelia burgdorferi

The outer surface lipoprotein (osp) layer forms an interface between the internal and the external environment of the Lyme disease spirochete, Borrelia burgdorferi. The homeostatic maintenance of the osp layer effectuates adaptation of B. burgdorferi as it gets transmitted from the tick vector to a mammalian host and vice-versa. However, the regulation of the outer surface lipoproteins (osps) is still a conundrum for borrelia scientists. Part of this dissertation inquires about the homeostatic maintenance of the osp layer. We found that the deletion of the dominantly expressed tick phase osp, OspA, induces expression of two other osps. OspD, and BBJ41. Also, increased expression of OspC was seen in borrelia mutants lacking OspA, OspD, and BBJ41. These results suggest constant osp layer maintenance, irrespective of the presence or the absence of the dominant Osps, like OspA and OspC. Furthermore, our conclusive electron microscopic study demonstrates that the overall density of the osp layer remains identical in wild type and mutant B. burgdorferi, lacking either several osps or the dominantly expressed OspA. OspA is abundantly expressed on the borrelial surface as it persists in an unfed tick. A blood meal causes rapid downregulation of OspA as B.burgdorferi prepares to infect the mammalian host. The downregulation of OspA is speculated to be regulated by an unknown repressor protein. The remaining part of this dissertation pertains to the investigation of this unknown repressor protein for ospA. The borrelia oxidative stress regulator protein, BosR, has been attributed with an indirect role in OspA downregulation. However, due to its homolgy with a family of transcriptional repressors, BosR is more likely to cause direct repression of OspA. Therefore, we investigated the direct interaction of BosR and the ospA regulatory region. The DNA binding experiments demonstrated that borrelia oxidative stress regulator, BosR, binds directly to the cisI and cisII regulatory regions of ospA promoter. Thus, conclusively, BosR acts as a repressor protein which causes OspA downregulation in B. burgdorferi

Regional nitrogen cycle: an Indian perspective

During the past century through food and energy production, human activities have altered the world's nitrogen cycle by accelerating the rate of reactive nitrogen creation. India has made impressive strides in the agricultural front, in which N fertilizer plays a major role. There has been a marked change in the supply and use of land, water, fertilizers, seeds and livestock, but the N use efficiency remained at a low level. Exploring the nature of these changes and quantification of the impacts on the N cycle has become essential. Hence we have presented data on various N pools and fluxes based on a conceptual N model. In India, efforts should focus on understanding the fate and consequences of the applied N and to increase the efficiency of N use

A rare case presentation of large mucinous ovarian cystadenocarcinoma in a young female

Here authors report a case of large ovarian mucinous cystadenocarcinoma in a young female complicating young pregnancy. Ovarian mucinous adenocarcinoma is a rare ovarian tumour that arises from the surface epithelium of the ovary. A 25-year young female, 9 days post-partum presented to the hospital with complain of abdominal distension. USG finding suggesting large solid cystic mass 36 × 14 cm arising from pelvis extending up to epigastrium. MRI pelvis evident of heterogenous hyperintense solid cystic mass lesion giving bunch of grapes appearance with size 24.5 × 25 × 11.5 cms seen in intra peritoneal space extending cranially up to epigastrium and caudally into pelvis giving anterior displacement of uterus.  And posterior displacement of bowel loops. A large part of lesion is cystic with solid component with multiple internal echoes

Supernumerary marker chromosome and global developmental delay: Role of microarray - case report and review of literature

Small supernumerary marker chromosomes (sSMCs) are defined as structurally abnormal chromosomes that cannot be identified or characterized by conventional karyotype analysis and are generally equal in size or smaller than chromosome 20. Here, we present the molecular characterization of an sSMCs derived from chromosome 15 in prenatal diagnosis in a 38-years-old femal

Mammalian translation termination intermediates captured using PDMS microfluidics-based time-resolved cryo-EM (TRCEM)

Termination of translation in eukaryotes occurs when a translating ribosome encounters a stop codon (UAA, UAG, or UGA) in its A site. This triggers the recruitment of translation termination factors eRF1, a tRNA-mimicking protein responsible for decoding the stop codon and catalyzing peptide release, and eRF3, a translational GTPase that stimulates peptide release in a GTP-hydrolysis-dependent manner. Upon successful stop codon decoding by eRF1, eRF3 carries out GTP hydrolysis and dissociates from the ribosome. eRF1 subsequently gets accommodated into the peptidyl transferase center (PTC) and catalyzes the release of the nascent peptide. The structures for the pre-accommodated eRF1 with eRF3 trapped on ribosome using non-hydrolysable GTP analogs as well as for the PTC-accommodated eRF1 have been solved using cryogenic electron-microscopy (cryo-EM). The structures reveal the binding mode and interactions between the release factors and the pre-termination complex. However, the mechanism of eRF3 GTPase activation and subsequent eRF1 accommodation into the PTC remains poorly understood. To address this knowledge gap, we used single-particle time-resolved cryo-EM (TRCEM) to capture the structures of intermediates formed during the termination process. For our TRCEM experiments, we first developed a Polydimethylsiloxane (PDMS)-based modular microfluidic mixing-spraying device with a SiO₂ internal coating. The device has a SiO₂-coated PDMS-based 3D splitting-and-recombination (SAR) micro-mixer capable of mixing two fluids within 0.5 ms with more than 90% efficiency. The SiO₂coating strengthens the PDMS channels and acts as a hydrophilic barrier preventing sample adsorption to the PDMS surface. The micro-mixer is connected to a glass microcapillary that acts as the reaction channel. Channels of different lengths can be used to vary the overall reaction time between 10 ms and 1000 ms. The microcapillary is connected to a 3D micro-sprayer for generating a 3D plume of sprayed droplets. A cryo-EM grid is passed through the spray cone to collect droplets and is rapidly plunged into liquid cryogen for vitrification. By using TRCEM as well as the conventional blotting method for cryo-EM sample preparation, we captured the reaction between a pre-termination (pre-TC) mimic and the ternary complex of eRF1, eRF3, and GTP at reaction times of 450 ms, 900 ms, 15 s, and 10 min. Classification of the cryo-EM data resulted in maps for five distinct factor-bound classes. Four maps belonged to intermediates with densities for eRF1 and eRF3 bound to the pre-TC in varying conformations. The fifth map had a density matching the PTC-accommodated eRF1. Population analysis allowed us to arrange the classes chronologically and track the events leading to GTPase activation during the termination process. Atomic model building and refinement allowed us to determine the hydrolysis state of the eRF3-bound GTP and revealed the catalytic mechanism for GTP-hydrolysis. The models revealed a potential mechanism for GDP dissociation post-GTP-hydrolysis

Comparing difference in mean total protein, albumin and globulin based on severity of rhesus isoimmunization: a prospective study

Background: Maternal RBC alloimmunization results from exposure and response to a foreign RBC antigen. Transplacental fetal to maternal hemorrhage is the most common cause of alloimmunization. Rh incompatibility can lead to either fetuses with hydropic features or non-hydropic. The precise mechanism leading to the development of hydrops is uncertain. Biochemical markers have the potential to be used to assess the severity of problem. But of the mechanisms proposed none have been able to totally explain the phenomenon or predict the prognosis. Objective of this study wads to compare the difference in mean total protein, albumin and globulin bases on severity of isoimmunization and comparing it with normal controls.Methods: A Total of 40 pregnant patients were enrolled which included 10 hydropic fetuses of Rh isoimmunised mothers, 10 non hydropic fetuses of Rh isoimmunized mothers. Control group included 18 Rh positive women without any fetal complication and 2 fetuses in women undergoing cordocentesis. Blood sampling was done at time of intrauterine transfusion and sent for estimation of total proteins, albumin, globulin in fetal blood. Pregnancies were followed up till delivery and fetal outcome noted.Results: Mean total protein, albumin and globulin between hydropic, non hydropic group and control group (3.25, 2.17 and 1.18 g/dl) in hydropic, (4.14, 2.70 and 1.44 g/dl) in non hydropic and (4.42, 2.95 and 1.47 g/dl) in control group respectively. Mean total protein, albumin and globulin between mild hydropic (3.43, 2.30 and 2.10 g/dl) and severe hydropic group (2.59, 1.6 and 1.3 g/dl) respectively.Conclusions: There was significantly lower levels of serum total proteins, albumin and globulin in hydropic fetuses as compared to non hydropic fetuses. Thus, hypoproteinemia can be considered a strong marker for development of hydrops in Rh isoimmunized fetuses

Wheat crop inventory using high spectral resolution IRS-P3 MOS-B spectrometer data

Modular Optoelectronic Scanner (MOS-B) spectrometer data over parts of Northern India was evaluated for wheat crop monitoring involving (a) sub pixel wheat tractional area estimation using spectral unmixmg approach and (b) growth assessment b3 red edge shift at different phenological stages. Red shift of 10 nm was observed between crown root initiation stage to flowering stage. Wheat fraction estimates using linear spectral unmixing on Feb. 13. 1999 acquisition of MOS-B data bad high correlatiol7 {0.82) with estimates from Wide Field Sensor (WiFS) data acquired on same date by IRS-P3 platfonn. It was observed that live bands 14.5.8.12.13 MOS-B bands) are saffieient for signature separability of major land cover classes viz. wheat, urban, wasteland, and water based on purely spectral separability, criterion using Transformed Divergence (T.D.) approach. Higher number of bands saturated the T.D. values. [n contrast, performanee of sub pixel fractional area estimation using unmixing decreased drastically for eight bands (4.5.6,728.9. 12,13 MOS-B bands l chosen from optimal band selection criteria in comparison to full set of 13 bands. The relative deviation between area estimated from Wifs and MOS-B increased from 1.72 percent when all thirteen bands were used in unmixing to 26. I0 percent for the above eight bands

Assessment of the customized birth weight formula in a low risk Indian population

Background: Birth weight is probably the single most important factor that affects neonatal mortality, infant and childhood morbidity in both developed and developing countries. Objective of the study was to formulate a model for prediction of fetal weight at term based on individualized fetal growth parameters.Methods: 131 participant low risk gravidas were enrolled into the study. The participants underwent an ultrasound 7 days prior to delivery. All fetal variables of growth of a random 100 participants were incorporated in an equation derived using multiple regressions to predict birth weight at term. The new equation was then prospectively applied to another 31 pregnant women for validation. The diagnostic performance of the new regression formula was then compared to the Hadlock formula.Results: The customised birth weight formula predicted a higher accuracy with MPE±SD of 0.790±9. compared to the Hadlock formula with MPE±SD - 4.42±8.73. The new formula also explained a greater variance in birth weight of 56% compared to the Hadlock formula of 49%.Conclusions: The new model based on individualized fetal growth parameters recognizes the capacity to modulate an accurate final birth weight, thus emphasizing the need for customized population specific birth weight formulas

Future Indian earth observation systems

Indian Earth Observation (EO) capability has increased manifold since the launch of Bhasakra-I in 1979 to Cartosat-Z in 2007. Improvements are not only in spatial, spectral. temporal and radiometric resolutions but also in their coverage and value added products. It has also entered into the arena of passive and active microwave remote sensing. stereo viewing and viewing from the geo-synchronous platform at moderately high resolution. Observations specific to oceans and atmosphere are getting further emphasis. Demand for a constellation of satellites for monitoring disaster situations is strongly made. In this context, India has made extensive plans for continuity and enhancement in EO capability. not only towards its OWn national needs. but also as a contributing participant towards Global Earth Observation System of Systems (GEOSS). Major emphasis of the future plan has been to consolidate theme-specific satellites. in order to fill the gaps in observation including those for disaster monitoring and mitigation, and also to develop synergy with international missions for complementing and supplementing Indian missions. The future Indian EO systems include those for land applications-Resourcesat witli wide swath LlSS- Ill, high resolution Cartosat (0.3 m) and Imaging Radar (RISAT: C-band, multi- polarization). It also proposes to develop space based hyper-spectral sensor and atmospheric corrector. The future ocean application sensors include improved Ocean Color Monitor, Ku band scatterometer and a thermal IR sensor. The two major satellites dedicated for atmospheric observations are INSAT-3D with 6 channel imager and 19 channel sounder. and the ISRO-CNES joint venture Megha Tropiques with three sensors viz. MADRAS, SAPHIRE and ScaRab. Satellite for Argos and Ka band radio altimeter (SA RA I,). a joint ISRO-CNES mission is also underway. L-band polarimetric radiometer. hyper spectral sounder. rain radar, millimeter wave sounder, high resolution imager from geo-synchronous platform are some of the sensors being considered for future missions