Insight into the Effect of Submicellar Concentrations of Sodium Deoxycholate on the Structure, Stability, and Activity of Bovine and Human Serum Albumin: An Interesting Comparison between Single and Double Tryptophan Proteins.

The progressive escalation in the applications of bile salts in diverse fields has triggered research on their interaction with various biological macromolecules, especially with proteins. A proper understanding of the interaction process of bile salts, particularly in the lower concentrations range, with the serum albumin seems important since the normal serum concentration of bile salts is approximately in the micromolar range. The current study deals with a comprehensive and comparative analysis of the interaction of submicellar concentrations of sodium deoxycholate (NaDC) with two homologous transport proteins: bovine serum albumin (BSA) and human serum albumin (HSA). HSA and BSA with one and two tryptophans, respectively, provide the opportunity for an interesting comparison of tryptophan fluorescence behavior on interaction with NaDC. The study suggests a sequential interaction of NaDC in three discrete stages with the two proteins. A detailed study using warfarin and ibuprofen as site markers provides information about the sites of interaction, which is further confirmed by inclusive molecular dynamics simulation analysis. Moreover, the comparison of the thermodynamics and stability of the NaDC-serum albumin complexes confirms the stronger interaction of NaDC with BSA as compared to that with HSA. The differential interaction between the bile salt and the two serum albumins is further established from the difference in the extent of decrease in the esterase-like activity assay of the proteins in the presence of NaDC. Therefore, the present study provides important insight into the effect of submicellar concentrations of NaDC on the structure, stability, and activity of the two homologous serum albumins and thus can contribute not only to the general understanding of the complex nature of serum albumin-bile salt interactions but also to the design of more effective pharmaceutical formulations in the field of drug delivery and biomedical research.

Understanding the Association Between Obesity and Obstructive Sleep Apnea Syndrome: A Case-Control Study.

Introduction Obstructive sleep apnea (OSA) represents a sleep-related impairment linked to upper airway function. The question of whether OSA drives obesity or if shared underlying factors contribute to both conditions remains unresolved. Hence, this present study aims to understand the interplay between obstructive sleep apnea syndrome (OSAS) and obesity through in-depth analysis of anthropometric data within control subjects and OSA patients. Methodology A case-control study was conducted, which included 40 cases and 40 matched healthy controls. Study participants with reported symptoms of snoring, daytime drowsiness, or both were included in the study. All the study participants underwent comprehensive anthropometric assessments such as height, weight, body mass index (BMI), neck circumference, waist circumference, hip circumference, waist-to-hip ratio, skin-fold thickness, and thickness measurements of biceps, triceps, suprailiac, and subscapular muscles. Results Within the OSA group, significant disparities emerged in mean age, waist circumference, waist-to-hip ratio, and diverse fat accumulations encompassing visceral, subcutaneous, trunk, and subcutaneous leg fat. Notably, skin-fold thickness at specific sites - biceps, triceps, subscapula, and suprailiac - demonstrated considerable augmentation relative to the control group. Furthermore, mean values associated with height, weight, BMI, neck circumference, fat percentage, subcutaneous arm fat, entire arm composition, and trunk skeletal muscle either equaled or exceeded those in the control group. However, statistical significance was not attained in these comparisons. Conclusion This investigation underscored a pronounced correlation between numerous endpoints characterizing OSA patients and markers of obesity. Consequently, addressing altered levels of obesity-linked anthropometric variables through pharmacological interventions might hold promise as a pivotal strategy for improving symptoms associated with OSA.

Phosphatidylethanolamine and Cholesterol Promote Hemifusion Formation: A Tug of War between Membrane Interfacial Order and Intrinsic Negative Curvature of Lipids.

Membrane fusion is an important process for the survival of eukaryotes. The shape of lipids plays an important role in fusion by stabilizing nonlamellar fusion intermediates. Lipids with intrinsic positive curvature such as lysophosphatidylcholine and others inhibit hemifusion formation, whereas lipids having intrinsic negative curvature, e.g., phosphatidylethanolamine and cholesterol (CH), are known to promote hemifusion formation. In this work, we have measured the effect of dioleoylphosphatidylethanolamine (DOPE) and CH on the depth-dependent organization, dynamics, and fusion of dioleoylphosphatidylcholine membranes. Both DOPE and CH promote hemifusion formation despite their ability to order the interfacial and acyl chain region of the membrane and block water percolation at these regions. Generally, membrane ordering and inhibition of water percolation at the acyl chain region are detrimental to membrane fusion. This clearly emphasizes the importance of intrinsic negative curvature of lipids in membrane fusion. Interestingly, DOPE and CH show differential effects on the rate of hemifusion formation, which might be owing to their ability to induce order at the interfacial region and intrinsic negative curvature. Overall, our result is significant in understanding the role of lipidic shape in membrane fusion.

The Surrogacy Regulation Act of 2021: A Right Step Towards an Egalitarian and Inclusive Society?

With the advent of major scientific and technological advancements in obstetrics and gynecology, surrogacy is quickly becoming a viable alternative to enable people of all genders to become parents. However, its path toward reality is still fraught with legal and ethical dilemmas. With the Surrogacy Act of 2021 coming into effect earlier this year, the present article aims to dissect the various legal nuances involved while also considering the societal norms governing the actual scenario at ground zero. Our review discusses the aspects of eligibility criteria, the health implications, the rights of the surrogate mother and the child born, the financial burden, and compensation. We aimed to bring attention to this act and its implications on marginalized segments of society, with an attempt to bring beneficial changes for them. In this review, we provide viable alternatives adopted across the globe to solve the identified issues to make the present act non-discriminatory and more rewarding to all involved beneficiaries.

A novel heterozygote allele in caprine melanocortin 1 receptor (MC1R) gene: an association with heat stress traits.

Climate change negatively influences the productive and reproductive abilities of goats. There is a need to understand the relationship between heat stress and genes that may aid in the development of climate-resilient goats. Melanism variation in goats plays a role in thermoregulation, in which the melanogenic genes have a pleiotropic effect on the regulation of physiological responses and behavior that are altered due to heat stress in the animals. Thus, the present study was conducted to establish a possible association between the coat color gene (MC1R) and heat stress characteristics. The physiological responses and cortisol levels were recorded in forty different coat-colored goats. The genotyping of the animals revealed four SNPs at the 183rd (C/T), 332nd (C/G), 748th (G/T), and 801st (C/G) positions, among which the black and brown goat populations had novel SNPs at the 332nd position. Eight haplotypes were constructed, and an association study revealed that haplotypes (CCGG, TCGG, and CCTC) that were linked to white animals had lower cortisol values, rectal temperature, skin temperature, and respiration rate. The multivariate and cluster analyses revealed that the white goats were distinct from the rest of the goats. In addition, the docking results revealed the residues that were forming the interaction complex, which could play a role in melanogenesis in the animals and, in turn, the heat stress ability of the goats. Altogether, the results of the present study could pave the way for more research into coat color genes and their relationship with heat stress traits.

Identification of potential proteins translated from circular RNA splice variants.

Circular RNAs (circRNAs) are covalently closed RNA molecules generated from precursor RNAs by the head-to-tail backsplicing of exons. Hundreds of studies demonstrated that circRNAs are ubiquitously expressed and regulate cellular events by modulating microRNA (miRNA) and RNA-binding protein (RBP) activities. A few circRNAs are also known to translate into functional polypeptides regulating cellular physiology. All these functions primarily depend on the full-length sequence of the circRNAs. CircRNA backsplice junction sequence is the key to identifying circRNAs and their full-length mature sequence. However, some multi-exonic circRNAs exist in different isoforms sharing identical backsplice junction sequences and are termed circRNA splice variants. Here, we analyzed the previously published HeLa cell RNA-seq datasets to identify circRNA splice variants using the de novo module of the CIRCexplorer2 circRNA annotation pipeline. A subset of circRNAs with splice variants was validated by the circRNA-rolling circle amplification (circRNA-RCA) method. Interestingly, several validated circRNAs were predicted to translate into proteins by the riboCIRC database. Furthermore, polyribosome fractionation followed by quantitative PCR confirmed the association of a subset of circRNAs with polyribosome supporting their protein-coding potential. Finally, bioinformatics analysis of proteins derived from splice variants of circCORO1C and circASPH suggested altered protein sequences and structures that could affect their physiological functions. Together, our study identified novel circRNA splice variants and their potential translation into protein isoforms which may regulate various physiological processes.

Health research in the state of Odisha, India: A decadal bibliometric analysis (2011-2020).

Background: Bibliometric analyses are an important tool for evaluating health research outputs in terms of their distribution, trends, contributors, focus, and funding sources. The transition from millennium to sustainable development goals has led to a gradual shift in the health policy, and possibly, research priorities of low-income settings in the Empowered Action Group (EAG) states lagging in socioeconomic and health parameters, and also ranking low on innovations and research. In this study, we depict the recent trends, quantity, type, focus, and sources of health-related research in the EAG state of Odisha, India. Methods: Peer-reviewed published original research articles related to human health published between 1 January, 2011 and 31 December, 2020 and where the study population was the residents of Odisha, or the study site was in Odisha, exclusively or partially, were analyzed. The publication characteristics were tabulated, including the title, journal name, open access, date of publication, number of authors, designation of the authors, number of institutes involved, and name of the institute of the first author. The details of the study setting, study site, ethical clearance, and funding source were also analyzed. Results: The study identified 2,285 articles from database searches and included 666 articles after screening for bibliometric analysis. Most of the manuscripts had between three and six authors (43.5%). Two institutes from the state, the Regional Medical Research Center (ICMR-RMRC) and Kalinga Institute of Industrial Technology (KIIT), together contributed to 22.4% of the published manuscripts. Nearly 45.9% of the studies were community-based while 45.3% were hospital-based. While most of the published work was on infectious diseases, the proportion came down with time. An overwhelming majority of the studies were observational and less than 10% were experimental in design. Conclusions: The analysis shows a substantial increase in the number of publications in this decade. Priority setting of healthcare problems, increased funding, and capacity-building can give a much-necessitated impetus to more quality- and evidence-based research for aiding policy implementation and improvement of the overall health.

Pathogenicity and virulence of Rickettsia.

Rickettsiae include diverse Gram-negative microbial species that exhibit obligatory intracellular lifecycles between mammalian hosts and arthropod vectors. Human infections with arthropod-borne Rickettsia continue to cause significant morbidity and mortality as recent environmental changes foster the proliferation of arthropod vectors and increased exposure to humans. However, the technical difficulties in working with Rickettsia have delayed our progress in understanding the molecular mechanisms involved in rickettsial pathogenesis and disease transmission. Recent advances in developing genetic tools for Rickettsia have enabled investigators to identify virulence genes, uncover molecular functions, and characterize host responses to rickettsial determinants. Therefore, continued efforts to determine virulence genes and their biological functions will help us understand the underlying mechanisms associated with arthropod-borne rickettsioses.

PanCircBase: An online resource for the exploration of circular RNAs in pancreatic islets.

Circular RNAs (circRNAs) are a novel class of covalently closed RNA molecules that recently emerged as a critical regulator of gene expression in development and diseases. Recent research has highlighted the importance of novel circRNAs in the biosynthesis and secretion of insulin from ß-cells of pancreatic islets. However, all circRNAs expressed in pancreatic islets or ß-cells are not readily available in the database. In this study, we analyzed publicly available RNA-sequencing datasets of the pancreatic islets to catalog all circRNAs expressed in pancreatic islets to construct the PanCircBase (https://www.pancircbase.net/) database that provides the following resources: 1) pancreatic islet circRNA annotation details (genomic position, host gene, exon information, splice length, sequence, other database IDs, cross-species conservation), 2) divergent primers for PCR analysis of circRNAs, 3) siRNAs for silencing of target circRNAs, 4) miRNAs associated with circRNAs, 5) possible protein-coding circRNAs and their polypeptides. In summary, this is a comprehensive online resource for exploring circRNA expression and its possible function in pancreatic ß-cells.

Phenotypic and genetic changes associated with the seesaw effect in MRSA strain N315 in a bioreactor model.

OBJECTIVES: Over the past decade, daptomycin treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections has led to the emergence of daptomycin nonsusceptible (DAP-NS) MRSA strains and a subsequent interest in combinatorial antibiotic therapies. We investigated the phenotypic and genetic changes associated with the seesaw effect, which describes the correlation between daptomycin resistance and increased ß-lactam susceptibility in DAP-NS MRSA and the reverse phenomenon of DAP-NS strains acquiring renewed susceptibility to daptomycin after ß-lactam exposure. METHODS: A continuous bioreactor model was used to study the effects of incremental doses of daptomycin followed by oxacillin on MRSA strain N315. Minimum inhibitory concentrations for daptomycin and oxacillin were determined for the bioreactor-derived samples. Transmission electron microscopy and cytochrome C binding assays were used to measure cell wall thickness and cell membrane charge, respectively, in the bioreactor-derived samples. Whole-genome sequencing was used to identify mutations associated with the seesaw effect. RESULTS: Although daptomycin resistance conferred enhanced susceptibility to oxacillin, oxacillin treatment of DAP-NS strains was accompanied by a lowered minimum inhibitory concentration for daptomycin. Additionally, there was a reduction in relative positive cell surface charge and cell wall thickness. However, the mutations acquired in our DAP-NS populations were not accompanied by additional genomic changes after treatment with oxacillin, implicating alternative mechanisms for the seesaw effect. CONCLUSION: In this study, we successfully produced and characterized the seesaw effect in MRSA strain N315 in a unique bioreactor model.

Identification of Potential circRNA-microRNA-mRNA Regulatory Network in Skeletal Muscle.

Circular RNAs (circRNAs) are a newly discovered family of regulatory RNAs generated through backsplicing. Genome-wide profiling of circRNAs found that circRNAs are ubiquitously expressed and regulate gene expression by acting as a sponge for RNA-binding proteins (RBPs) and microRNAs (miRNAs). To identify circRNAs expressed in mouse skeletal muscle, we performed high-throughput RNA-sequencing of circRNA-enriched gastrocnemius muscle RNA samples, which identified more than 1,200 circRNAs. In addition, we have identified more than 14,000 and 15,000 circRNAs in aging human skeletal muscle tissue and satellite cells, respectively. A subset of abundant circRNAs was analyzed by RT-PCR, Sanger sequencing, and RNase R digestion assays to validate their expression in mouse skeletal muscle tissues. Analysis of the circRNA-miRNA-mRNA regulatory network revealed that conserved circNfix might associate with miR-204-5p, a suppressor of myocyte enhancer factor 2c (Mef2c) expression. To support the hypothesis that circNfix might regulate myogenesis by controlling Mef2c expression, silencing circNfix moderately reduced Mef2c mRNA expression and inhibited C2C12 differentiation. We propose that circNfix promotes MEF2C expression during muscle cell differentiation in part by acting as a sponge for miR-204-5p.

Interferon-Lambda Intranasal Protection and Differential Sex Pathology in a Murine Model of SARS-CoV-2 Infection.

Outbreaks of emerging viral pathogens like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are a major medical challenge. There is a pressing need for antivirals that can be rapidly deployed to curb infection and dissemination. We determined the efficacy of interferon lambda-1 (IFN-λ) as a broad-spectrum antiviral agent to inhibit SARS-CoV-2 infection and reduce pathology in a mouse model of disease. IFN-λ significantly limited SARS-CoV-2 production in primary human bronchial epithelial cells in culture. Pretreatment of human lung cells with IFN-λ completely blocked infectious virus production, and treatment with IFN-λ at the time of infection inhibited virus production more than 10-fold. To interrogate the protective effects of IFN-λ in response to SARS-CoV-2 infection, transgenic mice expressing the human angiotensin-converting enzyme 2 (ACE-2) were tested. One dose of IFN-λ administered intranasally was found to reduce animal morbidity and mortality. Our study with SARS-CoV-2 also revealed a sex differential in disease outcome. Male mice had higher mortality, reflecting the more severe symptoms and mortality found in male patients infected with SARS-CoV-2. The results indicate that IFN-λ potentially can treat early stages of SARS-CoV-2 infection and decrease pathology, and this murine model can be used to investigate the sex differential documented in COVID-19. IMPORTANCE The COVID-19 pandemic has claimed millions of lives worldwide. In this report, we used a preclinical mouse model to investigate the prophylactic and therapeutic value of intranasal IFN-λ for this acute respiratory disease. Specific vaccines have been responsible for curbing the transmission of SARS-CoV-2 in developed nations. However, vaccines require time to generate and keep pace with antigenic variants. There is a need for broad-spectrum prophylactic and therapeutic agents to combat new emerging viral pathogens. Our mouse model suggests IFN-λ has clinical utility, and it reflects the well-documented finding that male COVID-19 patients manifest more severe symptoms and mortality. Understanding this sex bias is critical for considering therapeutic approaches to COVID-19.

HSF1 and GM-CSF expression, its association with cardiac health, and assessment of organ function during heat stress in crossbred Jersey cattle.

The study aimed to evaluate the differential expression of HSF1 and GM-CSF mRNA in PBMCs and correlate it with myocardial injury in crossbred Jersey heifers during heat stress. The study also assessed the effect of heat stress on cardiac electrical activity, vascular health, liver function and kidney function. The experiment was conducted in two phases: for heat stressed animals; HS in June (THI ranged from 80.0 to 89.8) and for control group i.e. not exposed to heat stress in January (THI ranged between 70.1 and 71.4). Results of the study revealed that the relative abundance of HSF1 and GM-CSF mRNA increased significantly (P < 0.05) in HS. Serum cardiac biomarkers such as CK-MB, AST and CRP were significantly elevated (P < 0.05) in HS. cTnI was detected 'positive' in nineteen out of twenty four cases in HS. Correlation of HSF1 and GM-CSF expression with concentration of LDH, CKMB, CRP and AST in HS was negative but non-significant (P > 0.05). Significant (P < 0.05) ECG findings in HS were increased heart rate, decreased RR interval, decreased PR interval, decreased QRS amplitude and decreased amplitude of P wave. Marked reduction (P < 0.05) in serum cholesterol and triglyceride levels was observed in HS. ALP, AST, bilirubin and urea levels in serum were significantly elevated (P < 0.05) in HS. In conclusion, cardiac enzymes in serum were significantly elevated in HS indicating myocardial injury. HSF1 and GM-CSF mRNA expression alone was inadequate in conferring cytoprotection to cardiac cells in HS. Cardiac electrical activity, vascular status, liver and kidney function were significantly altered in HS.

Virulence potential of Rickettsia amblyommatis for spotted fever pathogenesis in mice.

Rickettsia amblyommatis belongs to the spotted fever group of Rickettsia and infects Amblyomma americanum (Lone Star ticks) for transmission to offspring and mammals. Historically, the geographic range of A. americanum was restricted to the southeastern USA. However, recent tick surveys identified the progressive northward invasion of A. americanum, contributing to the increased number of patients with febrile illnesses of unknown etiology after a tick bite in the northeastern USA. While serological evidence strongly suggests that patients are infected with R. amblyommatis, the virulence potential of R. amblyommatis is not well established. Here, we performed a bioinformatic analysis of three genome sequences of R. amblyommatis and identified the presence of multiple putative virulence genes whose products are implicated for spotted fever pathogenesis. Similar to other pathogenic spotted fever rickettsiae, R. amblyommatis replicated intracellularly within the cytoplasm of tissue culture cells. Interestingly, R. amblyommatis displayed defective attachment to microvascular endothelial cells. The attachment defect and slow growth rate of R. amblyommatis required relatively high intravenous infectious doses to produce dose-dependent morbidity and mortality in C3H mice. In summary, our results corroborate clinical evidence that R. amblyommatis can cause mild disease manifestation in some patients.

Identification and Characterization of Circular Intronic RNAs Derived from Insulin Gene.

Circular RNAs (circRNAs) are a large family of noncoding RNAs that have emerged as novel regulators of gene expression. However, little is known about the function of circRNAs in pancreatic ß-cells. Here, transcriptomic analysis of mice pancreatic islet RNA-sequencing data identified 77 differentially expressed circRNAs between mice fed with a normal diet and a high-fat diet. Surprisingly, multiple circRNAs were derived from the intron 2 of the preproinsulin 2 (Ins2) gene and are termed as circular intronic (ci)-Ins2. The expression of ci-Ins2 transcripts in mouse pancreatic islets, and ßTC6 cells were confirmed by reverse transcription PCR, DNA sequencing, and RNase R treatment experiments. The level of ci-Ins2 was altered in ßTC6 cells upon exposure to elevated levels of palmitate and glucose. Computational analysis predicted the interaction of several RNA-binding proteins with ci-Ins2 and their flanking region, suggesting their role in the ci-Ins2 function or biogenesis. Additionally, bioinformatics analysis predicted the association of several microRNAs with ci-Ins2. Gene ontology and pathway analysis of genes targeted by miRNAs associated with ci-Ins2 suggested the regulation of several key biological processes. Together, our findings indicate that differential expression of circRNAs, especially ci-Ins2 transcripts, may regulate ß-cell function and may play a critical role in the development of diabetes.

An in vivo and in silico analysis of novel variation in TMBIM6 gene affecting cardiopulmonary traits of Indian goats.

Transmembrane Bax Inhibitor Motif-containing 6 (TMBIM6) gene acts as calcium leak channel and negatively regulates autophagy and autophagosome formation. The TMBIM6 gene was amplified and searched for variation in three different goat populations (i.e. Black Bengal, Ganjam and Raighar) of Odisha state of the India. The result indicated two substitutions i.e. 55th position (C55T) and 95th position (C95A) in the amplified region of the gene resulting in change of amino acids (Leu > Phe and Thr > Asn). The identified SNPs were combined to form haplotypes and animals were grouped accordingly. Structural analysis showed minor changes (5%) in between mutant and wild TMBIM6 protein structures. However, any functional variation could not be identified with respect to the calcium ligand and open pore state. But an alteration of calcium binding site was found. The binding interaction of calcium with the TMBIM6 protein was hydrophobic in nature in closed state whereas hydrophilic in open pore stage. The stress releasing function was the result of calcium leakage controlled by amino acids coded by exon 4 and exon 5 regions of TMBIM6 gene. The effect of breed and haplotype on cardiopulmonary traits was studied. The data on cardiopulmonary traits of body i.e. rectal temperature, skin temperature, heart rate and respiration rate were recorded when ambient temperature usually remained the highest. The statistical analysis showed, significant difference in rectal temperature, skin temperature and respiration rate among these goat populations. The haplotypes (CC and TA) were found to have a significant (P < 0.05) effect on rectal temperature, skin temperature and respiration rate. However, any such significant effect could not be identified in recorded heart rate. The objective of the present study to identify the genetic variations in TMBIM6 gene having significant effect on cardiopulmonary traits which can be further uses as the molecular markers to improve heat tolerance mechanism in goats.

Photophysical Properties of Coumarin 1 in Bile Salt Aggregates: An Insight into the Role of Bile Salt Structure on the Aggregation Behavior.

The photophysical behavior of Coumarin 1 (Cou1), a well-known 7-aminocoumarin derivative, is very sensitive to the microenvironment in which it resides. In the present study, the effect of six bile salt variants on the photophysical behavior of Cou1 has been investigated. Dihydroxy (deoxycholates) as well as trihydroxy (cholates) bile salts with conjugated and unconjugated side chains have been chosen to get insight into the role of bile salt structure on the microenvironment of Cou1. Cou1 photophysics was found to be extremely sensitive to the aggregation process of the bile salt variants. The reduced polarity of the micellar environment stabilizes the planar intramolecular charge transferred state of Cou1, resulting in significant modulation in its photophysics in the bile salt media. The changes in the fluorescence parameters such as fluorescence intensity, emission energy, fluorescence quantum yield, anisotropy, and lifetime of Cou1 reveal that there is a distinct difference in the aggregation behavior of deoxycholates from that of cholates. The deoxycholates form micelles more or less critically similar to those of conventional surfactants, whereas the cholates self-assemble rather noncritically over a wide concentration range, thus signifying the vital role of the extra hydroxyl group in the aggregation pattern of trihydroxy bile salts. The conjugated bile salts are found to provide a relatively more compact, rigid, and hydrophobic microenvironment to Cou1 as compared to their unconjugated counterparts. Considering the significant modulation in the photophysical properties of Cou1, it has been employed as a molecular reporter for monitoring the aggregation process of bile salt variants and important information could be obtained about the effect of bile salt structure on the aggregation pattern and also about the micellar properties.

Common variable immunodeficiency syndrome with chronic diarrhoea.

Common variable immunodeficiency syndrome (CVID) is a heterogeneous disorder characterised by diminished levels of IgG, IgA and/or IgM, and recurrent bacterial infections. Sinopulmonary infections are most commonly reported followed by gastrointestinal (GI) infections. GI tract represents the largest immune organ with abundance of lymphoid cells, its involvement can manifest variably ranging from asymptomatic involvement to florid symptoms and signs. Diffuse nodular lymphoid hyperplasia (DNLH) of the GI tract is characterised by numerous small polypoid nodules of variable size in the small intestine, large intestine or both. It is commonly seen in association to immunodeficiency states such as CVID, IgA deficiency and chronic infections due to Giardia lamblia and Helicobacter pylori and cryptosporidiosis. Repetitive antigenic stimulation leads to lymphoid hyperplasia. We herein describe a case of DNLH of the intestine and another case of duodenal cytomegalovirus (CMV) infection associated with CVID.

Insights Into the Evolution of Staphylococcus aureus Daptomycin Resistance From an in vitro Bioreactor Model.

The extensive use of daptomycin for treating complex methicillin-resistant Staphylococcus aureus infections has led to the emergence of daptomycin-resistant strains. Although genomic studies have identified mutations associated with daptomycin resistance, they have not necessarily provided insight into the evolution and hierarchy of genetic changes that confer resistance, particularly as antibiotic concentrations are increased. Additionally, plate-dependent in vitro analyses that passage bacteria in the presence of antibiotics can induce selective pressures unrelated to antibiotic exposure. We established a continuous culture bioreactor model that exposes S. aureus strain N315 to increasing concentrations of daptomycin without the confounding effects of nutritional depletion to further understand the evolution of drug resistance and validate the bioreactor as a method that produces clinically relevant results. Samples were collected every 24 h for a period of 14 days and minimum inhibitory concentrations were determined to monitor the acquisition of daptomycin resistance. The collected samples were then subjected to whole genome sequencing. The development of daptomycin resistance in N315 was associated with previously identified mutations in genes coding for proteins that alter cell membrane charge and composition. Although genes involved in metabolic functions were also targets of mutation, the common route to resistance relied on a combination of mutations at a few key loci. Tracking the frequency of each mutation throughout the experiment revealed that mutations need not arise progressively in response to increasing antibiotic concentrations and that most mutations were present at low levels within populations earlier than would be recorded based on single-nucleotide polymorphism (SNP) filtering criteria. In contrast, a serial-passaged population showed only one mutation in a gene associated with resistance and provided limited detail on the changes that occur upon exposure to higher drug dosages. To conclude, this study demonstrates the successful in vitro modeling of antibiotic resistance in a bioreactor and highlights the evolutionary paths associated with the acquisition of daptomycin non-susceptibility.

Conformational transition of κ-casein in micellar environment: Insight from the tryptophan fluorescence.

Intrinsically disordered proteins (IDPs) are under intense analysis due to their structural flexibility and importance in biological functions. Minuscule modulation in the microenvironment induces significant conformational changes in IDPs, and these non-native conformations of the IDPs often induce aggregation and cause cell death. Changes in the membrane composition often change the microenvironment, which promote conformational change and aggregation of IDPs. κ-Casein, an important milk protein, belongs to the class of IDPs containing net negative charges. In this present work, we have studied the interaction of κ-casein with cetyltrimethyl ammonium bromide (CTAB), a positively charged surfactant, utilizing various steady state fluorescence, time-resolved fluorescence and circular dichroism spectroscopy. Our results clearly indicate that κ-casein undergoes at least two conformational transitions in presence of various concentrations of CTAB. The intrinsically disordered κ-casein assumes a partially folded conformation at lower concentration of CTAB, which adopts an unstructured conformation at higher concentration of CTAB. The partially folded conformation of κ-casein at a lower CTAB concentration might be induced by the favorable electrostatic interaction between the positively charged surfactant headgroup and net negative charges of the protein, whereas surfactant nature of CTAB is being pronounced at higher concentration of CTAB.