A review on oligomeric polydispersity and oligomers-dependent holding chaperone activity of the small heat-shock protein IbpB of Escherichia coli

Inclusion body-associated proteins IbpA and IbpB of MW 16 KDa are the two small heat-shock proteins (sHSPs) of Escherichia coli, and they have only holding, but not folding, chaperone activity. In vitro holdase activity of IbpB is more than that of IbpA, and in combination, they synergise. Both IbpA and IbpB monomers first form homodimers, which as building blocks subsequently oligomerize to make heavy oligomers with MW of MDa range; for IbpB, the MW range of heavy oligomers is 2.0-3.0 MDa, whereas for IbpA oligomers, the values in MDa are not so specified/reported. By temperature upshift, such large oligomers of IbpB, but not of IbpA, dissociate to make relatively small oligomeric assemblies of MW around 600-700KDa. The larger oligomers of IbpB are assumed to be inactive storage form, which on facing heat or oxidative stress dissociate into smaller oligomers of ATP-independent holding chaperone activity. These smaller oligomers bind with stress-induced partially denatured/unfolded and thereby going to be aggregated proteins, to give them protection against permanent damage and aggregation. On withdrawal of stress, IbpB transfers the bound substrate protein to the ATP-dependent bi-chaperone system DnaKJE-ClpB, having both holdase and foldase properties, to finally refold the protein. Of the two sHSPs IbpA and IbpB of E. coli, this review covers the recent advances in research on IbpB only.

746 Single-Centre Experience with Three Metallic Ureteric Stents (Allium URS, Memokath-051 and Resonance) for Chronic Ureteric Obstruction

Aim

To evaluate efficacy of Allium URS, Memokath 051 and Resonance metallic ureteric stents as an alternative to polymer stents/nephrostomy in managing chronic ureteric obstruction (CUO).

Method

Retrospective analysis of consecutive patients with CUO managed with Allium URS, Memokath-051 or Resonance (September 2015/July 2020). Baseline patient variables (age, gender, underlying aetiology, ASA) and stricture characteristics (length, level, continuity) were recorded. Intra- and post-operative clinical and radiological follow-up assessments at 6 weeks, 3 months and then every 6 months, as well as any emergency attendances, were reviewed for placement success, stent complications, serum creatinine, and mortality. Outcomes included placement success rate, functional stent survival, and mean renal function.

Results

Overall, 129 stent insertion episodes (SIEs) (Allium URS: 23, Memokath 051: 48, Resonance: 58) occurred in 76 patients (Allium URS: 16; Memokath-051: 31; Resonance: 29). Placement success was high (Allium URS: 95.7%; Memokath-051 and Resonance: both 100%). Median functional stent survival was 11.4 months for Allium URS, 5.5 months for Memokath-051 and 11.7 months for Resonance. 47.8% of Allium URS SIEs (11/23), 64.6% of Memokath-051 SIEs (31/48) and 19% of Resonance SIEs (11/58) experienced complication (most frequently obstruction followed by migration and infection). There were no complications for Resonance SIEs for benign indication. In the first year following SIE, serum creatinine ranged from +21.3% to + 46.7% for Allium URS, -7.8% to + 8.9% for Memokath-051, and -9.4% to + 27.3% for Resonance.

Conclusions

Allium URS, Memokath 051 and Resonance metallic ureteric stents are all viable management options of CUO. Resonance was particularly efficacious for patients with benign aetiology.

525 Minimally Invasive Surgical Treatment of Benign Prostatic Hyperplasia: A Systematic Review

Introduction

Minimally invasive surgical treatments (MISTs) of benign prostatic hyperplasia (BPH) have evolved to offer men daycase care with preservation of urinary continence and sexual function. This systematic review evaluates trends in minimally invasive BPH surgery over the last decade

Method

Systematic review (PRISMA) of Embase/MEDLINE databases (2010-2020). MISTs included Rezum, Urolift, Prostatic Artery Embolisation (PAE), Temporary Implantable Nitinol Device (TIND), Intraprostatic Injection, Transurethral Microwave Therapy (TUMT) and Transurethral Needle Ablation (TUNA). Primary outcome: urinary functional change (International Prostate Symptom Score (IPSS)/maximum flow (Qmax)). Secondary outcomes: sexual functional change (International Index of Erectile Function-5 (IIEF-5)), technical failures and complications.

Results

74 studies were included (total: 8,917 patients). Primary: all interventions offered improvement in IPSS and Qmax (intervention (no. studies): range IPSS change, range Qmax change, range months follow-up; Rezum (4): -46.7% to -62.7%, +17.6% to + 55.6%, 6-48; Urolift (11): -35.2% to -64.2%, +16.7% to + 89.6%, 1-60; PAE (36): -36.8% to -85.2%, +17.4% to + 155.2%, 3-38; TIND (2): -36.8% to -59.6%, +32.9% to + 95.9%, 12-36; Intraprostatic Injection (14): -24.3% to -62%, +8.7% to + 98.4%, 3-24; TUMT (4): -56.1% to -58.7%, +12.9% to + 60.2%, 6-60; TUNA (3): -17.6% to -63.2%, +3.9% to + 39%, 1-120). Secondary: 33 studies of all interventions bar TIND and TUMT reported IIEF-5 change; sexual function was largely preserved. Technical failures and Clavien-Dindo ≥3 complications were rare.

Conclusions

MISTs for BPH are efficacious and safe. Randomised comparisons with long-term urinary and sexual follow-up are needed to guide choice; until then, patients should be carefully counselled based on individual priorities and circumstances.

Elucidation of Diverse Physico-Chemical Parameters in Mammalian Small Heat Shock Proteins: A Comprehensive Classification and Structural and Functional Exploration Using In Silico Approach

Small heat shock proteins (sHSPs), often known as molecular chaperones, are most prevalent in nature. Under certain stress-induced conditions, these sHSPs act as an ATP-independent variation and thus prevent the inactivation of various non-native substrate proteins and their aggregation. They also assist other ATP-dependent chaperones in the refolding of these substrates. In the case of prokaryotes and lower eukaryotes, the chaperone functions of sHSPs can bind a wide range of cellular proteins but preferentially protect translation-related proteins and metabolic enzymes. Eukaryotes usually encode a larger number of sHSPs than those of prokaryotes. The chaperone functions of mammalian sHSPs are regulated by phosphorylation in cells and also by temperature. Their sHSPs have different sub-cellular compartments and cell/tissue specificity. The substrate proteins of mammalian sHSPs or eukaryotic sHSPs accordingly reflect their multi-cellular complexity. The sHSPs of animals play roles in different physiological processes as cell differentiation, apoptosis, and longevity. In this work, the characterization, location, tissue specificity, and functional diversity of sHSPs from seven different mammalian species with special emphasis on humans have been studied. Through this extensive work, a novel and significant attempt have been made to classify them based on their omnipresence, tissue specificity, localization, secondary structure, probable mutations, and evolutionary significance.

A Computational Study to Prevent HIV Invasion by Bovine LF in Mucosal-Layer via Blocking of DC-SIGN_GP120 Interaction

Background:

Invasion of HIV in human occurs through DC-SIGN’s interaction via the mucosal lining during sexual transmission. Bovine Lactoferrin (bLF) has been known to hinder this invasion via its interaction with DC-SIGN. Hitherto, protein assays have taken place but molecular-level studies remain unexplored.

Methodology:

The 3D structures of the three proteins were studied. After protein docking (bLF_DCSIGN and gp120_DC-SIGN), the complexes underwent simulation. Stability parameters and binding patterns with residues were explored.

Results and Conclusion:

ΔG values, net area for solvent accessibilities and conformational fluctuations in DC-SIGN affirm the binding of bLF with DC-SIGN to be more spontaneous and steadier contrary to that with gp120. Residue participation inferred more interactions to occur from bLF complex with a greater percentage of arginine (which strengthens the interaction) while electrostatic interaction between Lys45 (bLF) and Glu26 (DC-SIGN) strengthened the complex. Arg37 played an active role from DC-SIGN to form the stabilizing charged-neutral H-bond, while Lys63 from bLF formed two more such stabilizing charged-neutral H-bond with DC-SIGN. The prime binding sites in DC-SIGN; Arg37 and Gln34 occupy helices. The binding pockets in DC-SIGN may be blocked by bLF spontaneously, to hinder their interaction with gp120. No ionic-ionic interaction was observed from gp120_DCSIGN complex. 88th residue, which was a predominant residue in the binding pocket was found to experience a conformational shift from coils to sheets after interaction of DC-SIGN with bLF. This would instigate the pharmaceutical research as non-toxic LF would be economic as a remarkable peptide inhibitor opposing HIV.

Mutational Impact on the Interaction Between Human IL27 and gp130: In silico Approach for Defending HIV Infection

INTRODUCTION

With advances in proteomics, it is essential to investigate the molecularlevel participation of IL27 and gp130 to hinder HIV infection. Their interaction causes cell-cycle arrest in HIV+ cells by activating the receptor-associated JAK signaling and causing apoptosis of cancerous cells.

METHODOLOGY

The best human wild-type WT_IL27 model was prepared after varied molecular modeling techniques. The vital tyrosine residues in WT_IL27 were identified, mutated and IL27 was re-modeled. Both wild-type and mutant IL27 were docked individually with human gp130 ectodomain complex. Best cluster sized complex was opted and the complexes (WT and MT) were MD (molecular dynamics) simulated. Protein-protein interacting residues, binding patterns, thermodynamic stability, solvent accessibility and many such parameters were evaluated to affirm the stability in the mutant complex. Statistical significances were drawn too.

RESULT AND DISCUSSION

With statistical significances also, the mutant type (MT) IL27 was comprehended as the most stable one. Their functionality remained the same. Ionic interactions were the most dominating ones. Exceptionally several Arg residues from MT_IL27 appeared to play a major role, thereby stabilizing the simulated MT_IL27-gp130 complexes. Manifold energy estimations for the complexes, electrostatic potential and increment in %helices and %β-sheets revealed the simulated MT_IL27-gp130 complex to be more stable. In the MT_complex, residues forming 3-ten helices remained constant with major increase in α-helices. This thereby infers the complex as the steadiest and most interactive one.

CONCLUSION

The residual exploration with the detailed structural analysis would aid in the effective drug discovery by targeting the drugs at the interacting sites with the specific binding patterns as analyzed from the study. Conformational stability and other several parameters for thermodynamic stability and accomplishment of strong interaction were also explored. Altogether, this probe provides a limelight towards the mutational alterations in WT IL27, which might allow it to act as a strong peptide inhibitor by shielding HIV entry, more potently.

Patterns of lymph node sampling and the impact of lymph node density in favorable histology Wilms tumor: An analysis of the national cancer database

INTRODUCTION

There is controversy about the role of lymph node (LN) sampling or dissection in the management of favorable histology (FH) Wilms tumor (WT), specifically how it performed and how it may impact survival.

OBJECTIVE

The objective of this study was to analyze factors affecting LN sampling patterns and the impact of LN yield and density (number of positive LNs/LNs examined) on overall survival (OS) in patients with advanced-stage favorable histology Wilms tumor (FHWT).

METHODS

The National Cancer Database (NCDB) was queried for patients with FHWT during 2004-2013. Demographic, clinical and OS data were abstracted for those who underwent surgical resection. Poisson regression was performed to analyze how factors influenced LN yield. Patients with positive LNs had LN density calculated and were further analyzed.

RESULTS

A total of 2340 patients met criteria, with a median age at diagnosis of 3 years (range 0-78 years). The median number of LNs examined was three (range 0-87). Lymph node yield was affected by age, race, insurance, tumor size, laterality, advanced stage, LN positivity, and institutional volume. A total of 390 (16.6%) patients had LN-positive disease. Median LN density for these LN-positive patients was 0.38 (range 0.02-1) (Summary Figure). Estimated 5-year OS was significantly improved for those with LN density ≤0.38 vs. >0.38 (94% vs. 84.6%, P = 0.012). In this population, on multivariate analysis, age and LN density were significant predictors of OS.

DISCUSSION

It is difficult to compile large numbers of cases in rare diseases like WT, and fortunately a large administrative database such as the NCDB can serve as a great resource. However, administrative data come with inherent limitations such as missing data and inability to account for a variety of factors that may influence LN yield and/or OS (specimen designation, pathologist experience, surgeon experience/volume, institutional Children's Oncology Group (COG) association, etc.). In this specific disease, the American Joint Committee on Cancer staging (captured by the NCDB) is different than the COG WT staging system that is used clinically, and the NCDB does not capture oncologic outcomes beyond OS.

CONCLUSIONS

In a review of the NCDB, various factors associated with LN yield and observed LN density were identified to be significantly associated with OS in patients with LN-positive FHWT. This reinforces the need for adequate LN sampling at the time of WT surgery, to maximize surgical disease control. It was proposed that LN density as a metric may allow for improved risk-stratification, and possibly allow for therapeutic reduction in a sub-set of patients with low LN density.

DUAL ACTION OF ARECOLINE ON ADRENAL FUNCTION AND GLUCOSE-GLYCOGEN HOMEOSTASIS IN METABOLIC STRESS IN MICE

Background

People chew betel nut (Areca catechu) for physical work and stress reduction, but it contains arecoline, which has both therapeutic value and untoward effects on endocrine and gonadal functions.

Objective

Aim of the present study is to investigate its role on adrenal with its target in metabolic stress in mice.

Materials and methods

Mice were deprived of water / food, each for 5 days / treated with arecoline (10 mg / kg body wt daily for 5 days) / arecoline after water or food deprivation, for 5 days each.

Results

Water or food-deprivation caused adrenocortical hyperactivity, evident from abundance of enlarged mitochondria and smooth endoplasmic reticulum (SER) with elevation of corticosterone level (C: 68.31 ± 2.30, WD: 159.31 ± 4.10 / FD: 194.12 ± 3.40 μg/ mL). Arecoline treatment alone or in water deprivation (C: 68.31 ± 2.30, AR: 144.50 ± 4.33, AR+WD: 194.42 ± 3.35 μg/ mL) / food deprivation (AR + FD: 180.89 ± 4.51 μg/ mL) stress also stimulated adrenocortical activity as recorded in metabolic stress. In contrast, adrenomedullary activity was not altered following water/ food deprivation. Arecoline treatment alone or in metabolic stress suppressed adrenomedullary activity by showing depletion of chromaffin granules (E/NE?), epinephrine (E) and norepinephrine (NE) concentrations. Both the stress decreased blood glucose and liver glycogen levels. Arecoline treatment decreased blood glucose level, with a rise in liver glycogen level, but elevated blood glucose level in water deprivation unlike in starvation.

Conclusion

Arecoline alone or in metabolic stress involves adrenal and probably other endocrine glands (pancreas, posterior pituitary and rennin-angiotensin system) to maintain homeostasis in metabolic stress in mice.

Higgs physics at the CLIC electron-positron linear collider

The Compact Linear Collider (CLIC) is an option for a future [Formula: see text] collider operating at centre-of-mass energies up to [Formula: see text], providing sensitivity to a wide range of new physics phenomena and precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages: [Formula: see text], 1.4 and [Formula: see text]. The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung ([Formula: see text]) and [Formula: see text]-fusion ([Formula: see text]), resulting in precise measurements of the production cross sections, the Higgs total decay width [Formula: see text], and model-independent determinations of the Higgs couplings. Operation at [Formula: see text] provides high-statistics samples of Higgs bosons produced through [Formula: see text]-fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes [Formula: see text] and [Formula: see text] allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit.

Elucidation of the molecular mechanism of heat shock proteins and its correlation with K722Q mutations in Lon protease

Cells withstand the effects of temperature change with the help of small heat shock proteins IbpA and IbpB. The IbpAB protein complex interacts with Lon protease in their free form and gets degraded at physiological temperature when there is no temperature stress. However, the proteolytic degradation of IbpAB is diminished when Lon is mutated. The mutation K722Q in Lon brings about some structural changes so that the proteolytic interactions between the heat shock proteins with that of the mutated Lon protease are lost. However, the detailed molecular aspects of the interactions are not yet fully understood. In the present, we made an attempt to analyze the biochemical aspects of the interactions between the small heat shock proteins IbpAB with wild type and mutant Lon protease. We for the first time deciphered the molecular details of the mechanism of interaction of small heat shock proteins with Lon protease bearing K722Q mutation i.e. the interaction pattern of heat shock proteins with mutant Lon protease at physiological temperature in absence of proteolytic machinery. Our study may therefore be useful to elucidate the mechanistic details of the correlation with IbpA, IbpB and Lon protease.

Time-constrained mother and expanding market: emerging model of under-nutrition in India

Background

Persistent high levels of under-nutrition in India despite economic growth continue to challenge political leadership and policy makers at the highest level. The present inductive enquiry was conducted to map the perceptions of mothers and other key stakeholders, to identify emerging drivers of childhood under-nutrition.

Methods

We conducted a multi-centric qualitative investigation in six empowered action group states of India. The study sample included 509 in-depth interviews with mothers of undernourished and normal nourished children, policy makers, district level managers, implementer and facilitators. Sixty six focus group discussions and 72 non-formal interactions were conducted in two rounds with primary caretakers of undernourished children, Anganwadi Workers and Auxiliary Nurse Midwives.

Results

Based on the perceptions of the mothers and other key stakeholders, a model evolved inductively showing core themes as drivers of under-nutrition. The most forceful emerging themes were: multitasking, time constrained mother with dwindling family support; fragile food security or seasonal food paucity; child targeted market with wide availability and consumption of ready-to-eat market food items; rising non-food expenditure, in the context of rising food prices; inadequate and inappropriate feeding; delayed recognition of under-nutrition and delayed care seeking; and inadequate responsiveness of health care system and Integrated Child Development Services (ICDS). The study emphasized that the persistence of child malnutrition in India is also tied closely to the high workload and consequent time constraint of mothers who are increasingly pursuing income generating activities and enrolled in paid labour force, without robust institutional support for childcare.

Conclusion

The emerging framework needs to be further tested through mixed and multiple method research approaches to quantify the contribution of time limitation of the mother on the current burden of child under-nutrition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3189-4) contains supplementary material, which is available to authorized users.

Green synthesized cerium oxide nanoparticle: A prospective drug against oxidative harm

Cerium oxide nanoparticle (CeONP) of size 2-3nm was synthesized by a new, simple and green method at ambient temperature, using cerium nitrate as prime precursor and Aloe vera leaf extract as stabilizing agent. Of the two oxidation states (+3) and (+4) of cerium, it was dominantly present in (+3) state in CeONP and cyclic conversion of Ce(III)O→Ce(IV)O→Ce(III)O by reaction with H2O2 implied uninterrupted antioxidant property of CeONP. Moreover, the higher oxygen defect in the crystal lattice produced particles with higher antioxidant activity. CeONP was found to neutralize the deleterious effects of H2O2 viz., cell death, generation of intracellular reactive oxygen species and loss of connectivity in mouse neural cells. Therefore, CeONP might have potential use in future as an anti-oxidant drug.

In-silico characterization of Formin Binding Protein 4 Family of proteins

Members of the Formin Binding Protein 4 Family or the FNBP4 were indirectly reported to be associated with many of the biological processes. These proteins possess two WW domains. So far there are practically no reports regarding the characterization and classification of the protein by any means. Keeping in mind the importance of the proteins from this FNBP4 family, we have tried an in silico approach to come up with a comprehensive analysis of the proteins. We have analyzed the proteins by considering their sequence conservation, their phylogenetic distributions among the different organisms. We have also investigated the functional properties of the WW domains in the proteins. Finally, we have made an attempt to elucidate the structural details of the domains and predicted the possible modes of their interactions. Our findings show that FNBP4 is eukaryotic in its distribution and follows a trend of evolution where animal and plant homologues have evolved in an independent manner. While the WW domain is the only common motif present across the FNBP4 family of proteins, there are different classes (mainly two) of WW domains that are found among different FNBP4 proteins. Structure function predictions indicate a possible role of FNBP4 in either protein stabilization control or transcript processing. Our study on FNBP4 may therefore open up new avenues to generate new interest in this highly important but largely unexplored class of proteins. Future studies with proteins from this family may answer many important questions of protein-protein interactions in different biologically important processes.

Hypoglycosylation of dystroglycan due to T192M mutation: a molecular insight behind the fact

Abnormal glycosylation of dystroglycan (DG), a transmembrane glycoprotein, results in a group of diseases known as dystroglycanopathy. A severe dystroglycanopathy known as the limb girdle disease MDDGC9 [OMIM: 613818] occurs as a result of hypoglycosylation of alpha subunit of DG. Reasons behind this has been traced back to a point mutation (T192M) in DG that leads to weakening of interactions of DG protein with laminin and subsequent loss of signal flow through the DG protein. In this work we have tried to analyze the molecular details of the interactions between DG and laminin1 in order to propose a mechanism about the onset of the disease MDDGC9. We have observed noticeable changes between the modeled structures of wild type and mutant DG proteins. We also have employed molecular docking techniques to study and compare the binding interactions between laminin1 and both the wild type and mutant DG proteins. The docking simulations have revealed that the mutant DG has weaker interactions with laminin1 as compared to the wild type DG. Till date there are no previous reports that deal with the elucidation of the interactions of DG with laminin1 from the molecular level. Our study is therefore the first of its kind which analyzes the differences in binding patterns of laminin1 with both the wild type and mutant DG proteins. Our work would therefore facilitate analysis of the molecular mechanism of the disease MDDGC9. Future work based on our results may be useful for the development of suitable drugs against this disease.

Periodic dynamics of fermionic superfluids in the BCS regime

We study the zero temperature non-equilibrium dynamics of a fermionic superfluid in the BCS limit and in the presence of a drive leading to a time-dependent chemical potential μ(t). We choose a periodic driving protocol characterized by a frequency ω and compute the fermion density, the wavefunction overlap, and the residual energy of the system at the end of N periods of the drive. We demonstrate that the BCS self-consistency condition is crucial in shaping the long time behaviour of the fermions subjected to the drive and provide an analytical understanding of the behaviour of the fermion density nkF (where kF is the Fermi momentum vector) after a drive period and for large ω. We also show that the momentum distribution of the excitations generated due to such a drive bears the signature of the pairing symmetry and can be used, for example, to distinguish between s- and d-wave superfluids. We propose experiments to test our theory.

Ovotesticular disorder of sexual development due to 47,XYY/46,XY/45,X mixed gonadal dysgenesis in a phenotypic male presenting as cyclical haematuria: clinical presentation and assessment of long-term outcomes

Ovotesticular disorder of sexual differentiation (OTDSD) is a rare cause of disorder of sexual differentiation predominantly having 46,XX karyotype, female phenotype and ambiguous genitalia. We report a 15-year-old having male body habitus, axillary and pubic hair, well-developed penis and right-descended testis with history of penoscrotal hypospadias correction, presenting with three episodes of cyclical haematuria, who biochemically had normal serum testosterone (338 ng dl(-1) ) which increased following hCG stimulation (614 ng dl(-1) ), elevated estradiol (17.35 pg ml(-1) ) along with elevated luteinising hormone (11.3 mIU l(-1) ) and follicle-stimulating hormone (31 mIU l(-1) ). Ultrasonography followed by micturating cystourethrogram and cystoscopy confirmed the presence of prostate, uterus, cervix and vagina draining into the urogenital sinus continuing till the penile urethra and left intra-abdominal gonad. Patient underwent hysterectomy and left gonadectomy. Histopathologic study of resected gonad confirmed presence of ovotestis. Low estradiol (1.2 pg ml(-1) ) following gonadectomy confirmed the ovotestis origin of estradiol. Chromosomal analysis revealed complex karyotype predominant being 47,XYY (50%) followed by 46,XY (26%) and 45,X (24%). This is perhaps the first report of 47,XYY/46,XY/45,X causing OTDSD in a phenotypic male.

A structural insight into the prokaryotic heat shock transcription regulatory protein σ(32): an implication of σ(32)-DnaK interaction

The heat shock response mechanism is a very vital biochemical process and is mainly controlled by σ(32) protein. The function of σ(32) is temperature dependent and at lower temperatures σ(32) is inactivated by its interactions with DnaK. This interaction is completely abolished above 42°C till date no molecular details of the interactions are available. In the present scenario, an attempt has been made to analyze first the predicted structure of σ(32) obtained by comparative modeling techniques and then to study the interactions between σ(32) and DnaK. From this molecular modeling study we could specifically identify the binding sites of the interactions of σ(32) with DnaK which will enlighten the mechanism of regulation of its activity and stability by DnaK. Our study provides the idea for future mutational experiments in order to find out the possible roles of the amino acids of region2 and region3 of σ(32) in stability as well as in binding with DnaK.

Microfluidic sorting with blinking optical traps

It is shown that by appropriately choosing the periodicity of a blinking optical trap only larger sized colloidal spheres can be selectively trapped out of a mixed population. This happens because smaller sized, more agile, spheres escape out of the trap volume during the off period of the trap beam. Therefore, by scanning an array of blinking traps over a mixed sample, bigger spheres can be forced to move with the traps and eventually could be taken to the output side. Experimental demonstration of sorting between 1 µm and 2 µm diameter silica spheres is presented.

Interdistrict variations in child health status and health services utilization: lessons for health sector priority setting and planning from a cross-sectional survey in rural India

BACKGROUND

There are limited data on interdistrict variations in child health status and health services utilization within the states of India. We conducted this study to identify and understand district-wise variations in child morbidity, mortality, healthcare seeking, and the status of health facilities in India.

METHODS

A cross-sectional population-based cluster survey was conducted from April to July 2007 in 16 districts of eight states in India. Two districts with similar demographic profile and health criteria were selected from each study state.

RESULTS

A total of 216 794 households and 24 812 under-5 children were surveyed. There were wide interdistrict variations in the health status of children within the same state and between different states across India. Interdistrict difference of >5 points/1000 live-births was found for infant mortality rate and under-5 mortality rate in all eight study states, while in six out of eight states this difference was >10 points/1000 live-births. Four states had a difference of >10 points/1000 live-births between respective districts for neonatal mortality rate. The interdistrict differences were also noted in childhood morbidity and health-seeking behaviour. Analysis of proportion of health facilities conforming to Indian public health standards revealed that the difference was m10% for availability of vaccines in five states, emergency services in three, laboratory services and logistics in four each, and referral facility in three of the eight study states.

CONCLUSION

This study underscores an important information gap in the country where planners seem to rely heavily on a few selected national-level databases that may not be adequate at the micro level. The current process of sporadic health surveys also appears inadequate and inappropriate. There is a need for district-specific data for planning, improving quality of service and generating demand for health service utilization to improve child survival in India. The findings of this study may prove useful for child health programme planning in India.

Evolutionary analysis of prokaryotic heat-shock transcription regulatory protein σ³²

Heat-stress to any living cell is known to trigger a universal defense response, called heat-shock response, with rapid induction of tens of different heat-shock proteins. Bacterial heat-shock genes are transcribed by the σ(32)-bound RNA polymerase instead of the normal σ(70)-bound RNA polymerase. In this study, the diversity in sequence, variation in secondary structure and function amongst the different functional regions of the proteobacterial σ(32) family of proteins, and their phylogenetic relationships have been analyzed. Bacterial σ(32) proteins can be subdivided into different functional regions which are referred to as regions 2, 3, and 4. There is a great deal of sequence conservation among the functional regions of proteobacterial σ(32) family of proteins though some mutations are also present in these regions. Region 2 is the most conserved one, while region 4 has comparatively more variable sequences. In the present work, we tried to explore the effects of mutations in these regions. Our study suggests that the sequence diversities due to natural mutations in the different regions of proteobacterial σ(32) family lead to different functions. So far, this study is the first bioinformatic approach towards the understanding of the mechanistic details of σ(32) family of proteins using the protein sequence information only. This study therefore may help in elucidating the hitherto unknown molecular mechanism of the functionalities of σ(32)family of proteins.

Kinetic and structural characterization of DmpI from Helicobacter pylori and Archaeoglobus fulgidus, two 4-oxalocrotonate tautomerase family members

The tautomerase superfamily consists of structurally homologous proteins that are characterized by a β-α-β fold and a catalytic amino-terminal proline. 4-Oxalocrotonate tautomerase (4-OT) family members have been identified and categorized into five subfamilies on the basis of multiple sequence alignments and the conservation of key catalytic and structural residues. Representative members from two subfamilies have been cloned, expressed, purified, and subjected to kinetic and structural characterization. The crystal structure of DmpI from Helicobacter pylori (HpDmpI), a 4-OT homolog in subfamily 3, has been determined to high resolution (1.8Å and 2.1Å) in two different space groups. HpDmpI is a homohexamer with an active site cavity that includes Pro-1, but lacks the equivalent of Arg-11 and Arg-39 found in 4-OT. Instead, the side chain of Lys-36 replaces that of Arg-11 in a manner similar to that observed in the trimeric macrophage migration inhibitory factor (MIF), which is the title protein of another family in the superfamily. The electrostatic surface of the active site is also quite different and suggests that HpDmpI might prefer small, monoacid substrates. A kinetic analysis of the enzyme is consistent with the structural analysis, but a biological role for the enzyme remains elusive. The crystal structure of DmpI from Archaeoglobus fulgidus (AfDmpI), a 4-OT homolog in subfamily-4, has been determined to 2.4Å resolution. AfDmpI is also a homohexamer, with a proposed active site cavity that includes Pro-1, but lacks any other residues that are readily identified as catalytic ones related to 4-OT activity. Indeed, the electrostatic potential of the active site differs significantly in that it is mostly neutral, in contrast to the usual electropositive features found in other 4-OT family members, suggesting that AfDmpI might accommodate hydrophobic substrates. A kinetic analysis has been carried out, but does not provide any clues about the type of reaction the enzyme might catalyze.

Sequence of the 3' untranslated region of brome mosaic virus coat protein messenger RNA

The 3' terminal 337 bases of BMV (brome mosaic virus) coat protein mRNA (BMV RNA4) are presented. This sequence includes the terminal portion of the coat protein cistron and the complete 300-base 3' noncoding sequence. The 3' noncoding sequence displays significant complementarity to the 5' terminal sequence of BMV RNA3 but not to the 5' terminal sequence of BMV RNA4.

Tertiary structural changes associated with iron binding and release in hen serum transferrin: a crystallographic and spectroscopic study

The iron binding and release of serum transferrin are pH-dependent and accompanied by a conformational change between the iron-bound (holo-) and iron-free (apo-) forms. We have determined the crystal structure of apo-hen serum transferrin (hAST) at 3.5A resolution, which is the first reported structure to date of any full molecule of an apo-serum transferrin and studied its pH-dependent iron release by UV-vis absorption and near UV-CD spectroscopy. The crystal structure of hAST shows that both the lobes adopt an open conformation and the relative orientations of the domains are different from those of apo-human serum transferrin and human apolactoferrin but similar to that of hen apo-ovotransferrin. Spectroscopic analysis reveals that in hen serum transferrin, release of the first iron starts at a pH approximately 6.5 and continues over a broad pH range (6.5-5.2). The complete release of the iron, however, occurs at pH approximately 4.0. The near UV-CD spectra show alterations in the microenvironment of the aromatic residues surrounding the iron-binding sites.

Three regulatory regions of the Aedes aegypti glutamine synthetase gene differentially regulate expression: identification of a crucial regulator in the first exon

Aedes aegyptiglutamine synthetase (GS) is expressed constitutively at various developmental stages and its relative mRNA abundance increases in the midgut following blood feeding in support of the biosynthesis of chitin, a component of the peritrophic matrix. To understand the regulation of GS expression better, GS-luciferase reporter fusion genes were constructed and analysed in transiently transfected C6/36 cells. These studies have identified three GS regions: GS-A, -B and -C (C1, C2) that are required for efficient transcription. The crucial regulatory DNA sequence is located within 140 nucleotides of the GS-C region in the first exon. GS-B region between -209 and +4 contains a negative modulator that represses transcription of the GS-C promoter, but the 5'-GS-A region, between -476 and -282, can negate the transcription inhibition of GS-B and promote GS transcription of the GS-C promoter. Electrophoretic mobility shift assays showed that nuclear proteins for GS-A, GS-B and GS-C1 are present in the C6/36 cells, and therefore that GS-A, GS-B and GS-C1 indeed possess regulatory function. By contrast, nuclear proteins isolated from both cultured cells and midgut tissues bound to GS-C2, suggesting that GS-C2 plays an important role in GS transcription and that GS-C2 is regulated by several different and redundant transcription factors to achieve constitutive expression in a wide variety of tissues.

Structure of diferric hen serum transferrin at 2.8 Å resolution

Hen serum transferrin in its diferric form (hST) has been isolated, purified and the three-dimensional structure determined by X-ray crystallography at 2.8 A resolution. The final refined structure of hST, comprising 5232 protein atoms, two Fe(3+) cations, two CO(3)(2-) anions, 54 water molecules and one fucose moiety, has an R factor of 21.5% and an R(free) of 26.9% for all data. The structure has been compared with the three-dimensional structure of hen ovotransferrin (hOT) and also with structures of some other transferrins, viz. rabbit serum transferrin (rST) and human lactoferrin (hLF). The overall conformation of the hST molecule is essentially the same as that of other transferrins. However, the relative orientation of the two lobes, which is related to the species-specific receptor-recognition property of transferrins, has been found to be different in hST from that in hOT, rST and hLF. On the basis of superposition of the N lobes, rotations of 5.8, 16.9 and 11.3 degrees are required to bring the C lobes of hOT, rST and hLF, respectively, into coincidence with that of hST. A number of additional hydrogen bonds between the two domains in the N and C lobes have been identified in the structure of hST compared with that of hOT, which indicate a greater compactness of the lobes of hST than those of hOT. Being products of the same gene, hST and hOT have 100% sequence identity and differ only in the attached carbohydrate moiety. On the other hand, despite having similar functions, hST and rST have only 51% sequence similarity. However, the nature of the interdomain interactions of hST are closer to rST than to hOT. A putative carbohydrate-binding site has been identified in the N lobe of hST at Asn52 and a fucose molecule could be modelled at the site. The variations in interdomain and interlobe interactions in hST, together with altered lobe orientation with respect to hOT, rST and hLF, which are the representatives of the other subfamily of transferrins, are discussed.

Haemosuccus pancreaticus: treatment by arterial embolization

AIM

Haemosuccus pancreaticus is bleeding into the pancreatic duct from a peripancreatic artery. This condition most commonly follows pseudoaneurysm formation secondary to acute or chronic pancreatitis. It is a rare disorder, challenging in both diagnosis and therapy. We present an eight-year experience of managing these patients using endovascular embolization as the primary therapy.

MATERIALS AND METHODS

We retrospectively reviewed the imaging, laboratory results and clinical notes of the five patients who presented to this institution between 1991-1999 with gastrointestinal bleeding subsequently found to be haemosuccus pancreaticus.

RESULTS

There were four men and one women aged 38-75 years. All had a history of gastrointestinal haemorrhage and had acute (n=1) or chronic pancreatitis with a complicating pseudoaneurysm. All underwent embolization as the primary therapy for the pseudoaneurysm. There was immediate technical success in all cases without major complication. No patient required operative surgery for the pseudoaneurysm. Follow-up ranged from 18 months to 7 years. One patient died four years after embolization due to hepatic failure but the other four remain well without further gastrointestinal bleeding.

CONCLUSION

Endovascular embolization is an effective and safe treatment for haemosuccus pancreaticus.

Purification and preliminary X-ray studies on hen serotransferrin in apo- and holo-forms

Serum transferrins are monomeric glycoproteins with a molecular mass of around 80 kDa, that transport iron to cells via receptor-mediated endocytosis. Although both serum transferrins (STfs) and ovotransferrins (OTfs) are derived from the same gene in aves, the ovotransferrins do not transport iron in vivo. Crystal structures of OTf have been solved, in contrast no three-dimensional structure of avian STf have been determined as yet. Here we report the purification, crystallization, and preliminary crystallographic studies of the hen STf both in apo- (iron free) and holo- (iron loaded) forms. The hen STf has been purified to homogeneity by hydrophobic interaction chromatography. Both the apo- and holo-forms were crystallized by hanging drop vapor diffusion method at 277 K. The apo-crystals diffract to a resolution of 3.0 A and belong to the space group P4(3)2(1)2 with unit cell parameters a=b=90.5 and c=177.9 A. The holo-crystals diffract to a resolution of 2.8 A and belong to space group P2(1) with a=72.8, b=59.6, c=88.2 A, and beta=95.7 degrees.

Glucosamine:fructose-6-phosphate aminotransferase: gene characterization, chitin biosynthesis and peritrophic matrix formation in Aedes aegypti

Glucosamine:fructose-6-phosphate aminotransferase (GFAT) catalyses the formation of glucosamine 6-phosphate and is the first and rate-limiting enzyme of the hexosamine biosynthetic pathway. The final product of the hexosamine pathway, UDP-N-acetyl glucosamine, is an active precursor of numerous macromolecules containing amino sugars, including chitin in fungi and arthropods. Chitin is one of the essential components of insect cuticle and peritrophic matrix. The peritrophic matrix is produced in the midgut of mosquitoes in response to bloodfeeding, and may affect vector competence by serving as a physical barrier to pathogens. It is hypothesized that GFAT plays a regulatory role in biosynthesis of chitin and peritrophic matrix formation in insects. We cloned and sequenced the GFAT gene (AeGfat-1) and its 5' regulatory region from Aedes aegypti. There is no intron in AeGfat-1 and there are two potential transcription start sites. AeGfat-1 cDNA is 3.4 kb in length and its putative translation product is 75.4 kDa. The amino acid sequence of GFAT is highly conserved in lower and higher eukaryotes, as well as in bacteria. AeGfat-1 message is constitutively expressed but is gradually up-regulated in the midgut after bloodfeeding. The putative regulatory region of the gene contains the ecdysone response element, E74, and Broad complex motifs, similar to what is found in the glutamine synthetase gene in Ae. aegypti. Results suggest that Ae. aegypti GFAT-1 may have a regulatory role in chitin biosynthesis and peritrophic matrix formation, and probably is under the regulation of ecdysteroids.

Aedes aegypti glutamine synthetase: expression and gene structure

The peritrophic matrix (PM) is the first natural barrier a mosquito-borne parasite faces when ingested with a blood meal; consequently, understanding the biology of PM formation could provide novel transmission control strategies. Because the PM is composed of chitin (a molecule of repeating units of N-acetyl glucosamine), glycoproteins and glucose, characterizing the regulation of enzymes involved in chitin production should provide information concerning factors that influence PM formation. We previously have shown that glutamine synthetase (GS) provides the glutamine needed in the initial steps of chitin biosynthesis in the yellow fever mosquito, Aedes aegypti. In the present study we show that GS is encoded by a single 4.5 kb gene, designated mGS, containing three exons and two introns. Multiple transcripts are generated from mGS presumably by differential splicing of the introns. Sequences of two cDNAs encoding GS are identical at the protein level, but differ in their 5'-untranslated regions. GS message is constitutively expressed in all developmental stages and in most tissues, with an increase in GS transcription observed in midgut and fat body tissues of female mosquitoes following a blood meal. Transcripts are localized to the apical side of the mosquito midgut epithelium and data suggest that mGS transcription is regulated by an Oct-1 transcription factor.

Systemic spread of an RNA insect virus in plants expressing plant viral movement protein genes

Flock house virus (FHV), a single-stranded RNA insect virus, has previously been reported to cross the kingdom barrier and replicate in barley protoplasts and in inoculated leaves of several plant species [Selling, B. H., Allison, R. F. & Kaesberg, P. (1990) Proc. Natl. Acad. Sci. USA 87, 434-438]. There was no systemic movement of FHV in plants. We tested the ability of movement proteins (MPs) of plant viruses to provide movement functions and cause systemic spread of FHV in plants. We compared the growth of FHV in leaves of nontransgenic and transgenic plants expressing the MP of tobacco mosaic virus or red clover necrotic mosaic virus (RCNMV). Both MPs mobilized cell-to-cell and systemic movement of FHV in Nicotiana benthamiana plants. The yield of FHV was more than 100-fold higher in the inoculated leaves of transgenic plants than in the inoculated leaves of nontransgenic plants. In addition, FHV accumulated in the noninoculated upper leaves of both MP-transgenic plants. RCNMV MP was more efficient in mobilizing FHV to noninoculated upper leaves. We also report here that FHV replicates in inoculated leaves of six additional plant species: alfalfa, Arabidopsis, Brassica, cucumber, maize, and rice. Our results demonstrate that plant viral MPs cause cell-to-cell and long-distance movement of an animal virus in plants and offer approaches to the study of the evolution of viruses and mechanisms governing mRNA trafficking in plants as well as to the development of promising vectors for transient expression of foreign genes in plants.