Incorporation of phenylcarbonyl groups in the sidechain: A tool to induce ordered assembly of peptides on surfaces.

The possibility of introducing various functionalities on peptides with relative ease allows them to be used for molecular applications. However, oligopeptides prepared entirely from proteinogenic amino acids seldom assemble as ordered structures on surfaces. Therefore, sidechain modifications of peptides that can increase the intermolecular interactions without altering the constitution of a given peptide become an attractive route to self-assembling them on surfaces. We find that replacing phenylalanine residues with unusual amino acids that have phenylcarbonyl sidechains in oligopeptides increases the formation of ordered self-assembly on a highly ordered pyrolytic graphite surface. Peptides containing the modified amino acids provided extended long-range ordered assemblies, while the analogous peptides containing phenylalanine residues failed to form long-range assemblies. X-ray crystallographic analysis of the bulk structures of these peptides and the analogous peptides containing phenylalanine residues reveal that such modifications do not alter the secondary structure in crystals. It also reveals that the secondary hydrogen bonding interaction through phenylcarbonyl sidechains facilitates extended growth of the peptides on graphite.

Synthesis of peptides containing oxo amino acids and their crystallographic analysis.

An isolated uncharged hydrogen bond acceptor such as the carbonyl functionality of an aldehyde or a keto group is absent in natural amino acids. Although glutamine and asparagine are known to hydrogen bond through the amide carbonyl group in their side chains, they also possess the amide NH2 group, which can act as a hydrogen bond donor. This makes the structural study of peptides containing an oxo residue, with an isolated carbonyl group in the side chain, interesting. Here, we report the synthesis of δ- and ε-oxo amino acids and their incorporation into oligopeptides as the N-terminal residue. The resultant oxo peptides were extensively studied using X-ray crystallography to understand the interactions offered by the oxo group in peptide crystals. We find that the oxo groups are capable of providing additional hydrogen bonding opportunities to the peptides, resulting in increased intermolecular interactions in crystals. The study thus offers avenues for the utilization of oxo residues to introduce intermolecular interactions in synthetic peptides.

High Frequency of Recessive WFS1 Mutations Among Indian Children With Islet Antibody-negative Type 1 Diabetes.

BACKGROUND: While the frequency of islet antibody-negative (idiopathic) type 1 diabetes mellitus (T1DM) is reported to be increased in Indian children, its aetiology has not been studied. We investigated the role of monogenic diabetes in the causation of islet antibody-negative T1DM. METHODS: We conducted a multicenter, prospective, observational study of 169 Indian children (age 1-18 years) with recent-onset T1DM. All were tested for antibodies against GAD65, islet antigen-2, and zinc transporter 8 using validated ELISA. Thirty-four islet antibody-negative children underwent targeted next-generation sequencing for 31 genes implicated in monogenic diabetes using the Illumina platform. All mutations were confirmed by Sanger sequencing. RESULTS: Thirty-five (21%) children were negative for all islet antibodies. Twelve patients (7% of entire cohort, 34% of patients with islet antibody-negative T1DM) were detected to have pathogenic or likely pathogenic genetic variants. The most frequently affected locus was WFS1, with 9 patients (5% of entire cohort, 26% of islet antibody-negative). These included 7 children with homozygous and 1 patient each with a compound heterozygous and heterozygous mutation. Children with Wolfram syndrome 1 (WS) presented with severe insulin-requiring diabetes (including 3 patients with ketoacidosis), but other syndromic manifestations were not detected. In 3 patients, heterozygous mutations in HNF4A, ABCC8, and PTF1A loci were detected. CONCLUSION: Nearly one-quarter of Indian children with islet antibody-negative T1DM had recessive mutations in the WFS1 gene. These patients did not exhibit other features of WS at the time of diagnosis. Testing for monogenic diabetes, especially WS, should be considered in Indian children with antibody-negative T1DM.

Heterogeneity in Kidney Histology and Its Clinical Indicators in Type 2 Diabetes Mellitus: A Retrospective Study.

The heterogeneous spectrum of kidney disease in diabetes ranges from albuminuric or non-albuminuric diabetic kidney disease to non-diabetic kidney diseases. Presumptive clinical diagnosis of diabetic kidney disease may lead to an erroneous diagnosis. MATERIAL AND METHOD: We analyzed the clinical profile and kidney biopsy of a total of 66 type 2 diabetes patients. Based on kidney histology, they were divided into-Class I (Diabetic Nephropathy), Class II (Non-diabetic kidney disease), and Class III (Mixed lesion). Demographic data, clinical presentation, and laboratory values were collected and analyzed. This study tried to examine the heterogeneity in kidney disease, its clinical indicator, and the role of kidney biopsy in the diagnosis of kidney disease in diabetes. RESULTS: Class I consisted of 36(54.5%), class II 17(25.8%), and class III 13(19.7%) patients. The commonest clinical presentation was nephrotic syndrome 33(50%) followed by chronic kidney disease 16(24.4%) and asymptomatic urinary abnormality 8(12.1%). Diabetic retinopathy (DR) was present in 27(41%) cases. DR was significantly higher in the class I patients (p < 0.05). Specificity and positive predictive values of DR for DN were 0.83 and 0.81, respectively (sensitivity 0.61; negative predictive values 0.64). The Association of the duration of diabetes and the level of proteinuria with DN was statistically not significant (p > 0.05). Idiopathic MN (6) and Amyloidosis (2) were the most common isolated NDKD; whereas diffuse proliferative glomerulonephritis (DPGN) (7) was the commonest NDKD in mixed disease. Another common form of NDKD in mixed disease was Thrombotic Microangiopathy (2) and IgA nephropathy (2). NDKD was observed in 5(18.5%) cases in presence of DR. We noted biopsy-proven DN even in 14(35.9%) cases without DR, in 4(50%) cases with microalbuminuria and 14(38.9%) cases with a short duration of diabetes. CONCLUSION: Almost half (45%) of cases with atypical presentation have non-diabetic kidney disease (NDKD), though even among these cases with atypical presentation diabetic nephropathy (either alone or in mixed form) is commonly seen in 74.2% of cases. DN has been seen in a subset of cases without DR, with microalbuminuria, and with a short duration of diabetes. Clinical indicators were insensitive in distinguishing DN Vs NDKD. Hence, a kidney biopsy may be a potential tool for the accurate diagnosis of kidney disease.

Subcutaneous entomophthoramycosis in a child presenting as panniculitis: a case report from Bihar, India.

A 5-year-boy from Bihar, India was admitted to a tertiary care hospital with painful swelling over both lower limbs and buttocks, which had been increasing progressively for the past 1 year. The condition was initially undiagnosed and was later misdiagnosed as non-infective panniculitis, delaying treatment. Subsequently, the patient was diagnosed with subcutaneous entomophthoramycosis caused by Basidiobolus spp. A preliminary diagnosis was made by considering the history, clinical features, radiological findings and histopathological examination of the biopsied tissue. The confirmatory diagnosis was made using conventional techniques on aspirated pus, which included KOH wet mount and fungal culture on Sabouraud dextrose agar tubes incubated at 28°C and 37°C, respectively. Lactophenol cotton blue mount and slide culture were performed for identification of the fungal isolate. The patient responded well to oral itraconazole and oral potassium iodide. Delayed diagnosis and extensive involvement in a rare case of subcutaneous entomophthoramycosis causing panniculitis emphasizes the importance of correct diagnosis and appropriate, effective treatment.

Synthesis of Novel Triazolyl/Oxadiazolyl/Thiadiazolyl-Piperazine as Potential Anticonvulsant Agents.

Reaction of piperazine with chloroacetylchloride in dry acetone yield compound 1: , which on reaction with hydrazine hydrate yielded compound 2: , which was further reacted with various substituted phenylisothiocyanates in absolute alcohol to afford compounds 3-8: i. e. 2-(carbazolylacetyl)-N-(substitutedphenyl)-hydrazinepiperazinothioamides. Compounds 3-8: on reaction with aqueous NaOH, ethanolic NaOH and conc. H2SO4 afford triazoles 9-14: , oxadiazoles 15-20: and thiadiazoles 21-26: respectively. Twenty four newly synthesized compounds were evaluated for their anticonvulsant activity and acute toxicity. The structures of these compounds were established on the basis of analytical and spectral data.

Neutralizing antibody response against subcutaneously injected bacteriophages in rabbit model.

Bacteriophage therapy is currently experiencing a renaissance. Therapeutic efficacy of bacteriophages depends on phage-bacterial and phage-host interactions. The appearance of neutralizing anti-phage antibody has been speculated to be one of the few reasons for bacteriophage therapy's failure. This study aimed to know whether there is a rise in the neutralizing antibody on the parenteral injection of bacteriophages in an animal model. This study included bacteriophages against five different bacteria, namely Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella Typhi and Staphylococcus aureus. These bacteriophages were isolated, propagated and purified. Bacteriophage specificity was confirmed by spot testing on the respective bacterial lawn. Weekly subcutaneous injection of purified bacteriophages (109PFU) was given to five rabbits for six weeks. Blood samples were collected before administering the next dose every week. The antibody response was tested by phage neutralization followed by plaque assay by using double agar overlay method. The rise in anti-phage neutralizing antibodies was observed usually after the 3rd week after immunization. Complete neutralization of bacteriophages could be seen between 3 and 5 weeks after immunization. A further rise in bacteriophage counts (PFU), especially on 1:1000 and 1:2000 serum dilutions, could be noticed by the end of 6th week against most bacteriophages injected. Background anti-phage neutralizing antibodies were observed against bacteriophage specific to Escherichia coli. However, it was absent against bacteriophages specific to other four bacteria. Bacteriophage interacts with mammalian host and induces anti-phages neutralizing antibody production. However, neutralization of phage depends on repeated administration and duration of therapy. The significant rise in neutralizing antibody could be seen at the end of 3rd week. Therefore, bacteriophage can be effectively used in acute cases where therapy duration is less than 2 weeks. However, for prolonged therapy, bacteriophage cocktail of different antigenicity may be suggested.