Convenient pH-responsive removal of Acid Black 1 by green l-histidine/iron oxide magnetic nanoadsorbent from water: performance and mechanistic studies

This study was aimed at developing green histidine-modified Fe₃O₄ nanoparticles (His-MNPs) for the adsorptive removal of Acid Black 1 (AB1) from aqueous solution. The His-MNPs were characterized by atomic force microscopy, scanning electron microscopy-energy dispersive X-ray spectrometry, infra-red spectra and thermogravimetry. These MNPs were spherical (average diameter 11–28 nm) with polydispersity index of 1.40 and about 13% mass coating of histidine. To optimize AB1 adsorption on His-MNPs and understand its mechanism, the influences of different operational variables (pH, adsorbent amount, temperature, initial AB1 concentration, contact time, ionic strength, etc.) on adsorption were examined with adsorption isotherms, kinetics and thermodynamic studies. The AB1 adsorption from water was fast with equilibrium time ≤ 45 min. The adsorption equilibrium was best fitted to the Langmuir isotherm model (q_max = 166.7 mg g⁻¹ at the adsorbent dose of 0.2 g L⁻¹, temperature 30 °C and pH 4). The linearity order for other isotherms was as follows: Dubinin–Radushkevich (D–R) < Temkin < Freundlich. The kinetics of the AB1 adsorption demonstrated the best compliance with the pseudo-second-order model, predominantly controlled by film diffusion as compared to intraparticle diffusion. Thermodynamic parameters (ΔH° and ΔG°) reflected the exothermic and spontaneous adsorption process. The values of ΔG°, ΔH°, activation energy and D–R free adsorption energy were all consistent with the physisorptive removal of AB1. The spectral (electronic and IR) and pH studies further corroborated the mechanism of AB1 removal by His-MNPs. The His-MNPs showed efficient adsorption, easy regeneration and excellent reusability, assisted by their pH-responsive properties. The prepared adsorbent can provide a safe, effective and economical alternative strategy for removing azo dyes from wastewater.

Effective and eco-friendly separation of Acid Black 1 dye from water by electrostatic adsorption onto reusable Histidine-Fe₃O₄ nanoparticles, credited to their pH-responsiveness.     

Sequence analysis of genes associated with resistance to chloroquine and sulphadoxine pyrimethamine in P. falciparum and P. vivax isolates from the Bannu district of Pakistan

Plasmodium vivax and Plasmodium falciparum are becoming resistant to drugs including antifolates, sulphonamides and chloroquine. This study was focused at sequence analysis of resistant genes of these parasites against sulphadoxine–pyrimethamine and chloroquine, from Bannu, Pakistan. Known mutations were detected at codons 57, 58 and 117 of pvdhfr gene of P. vivax, while none of the isolates had any pvdhps mutation. Similarly P. falciparum isolates exhibited double 59R + 108N mutations in pfdhfr, and single 437G in pfdhps thus demonstrating the existance of triple mutant 59R + 108N + 437G haplotype in this region. The key chloroquine resistance mutation, 76T in pfcrt was observed in 100% of the P. falciparum isolates, with haplotype SVMNT which is also associated with resistance to amodiaquine. Some novel mutations were also observed in pvdhfr and pfdhfr genes.     

Accumulation of Cadmium in Transplanted Lichen Pyxine cocoes (Sw.) Nyl., with Reference to Physiochemical Variation and Kinetics of Cadmium Biosorption

Bulletin of Environmental Contamination and Toxicology - The safe utilization and risk assessment of produced water (PW) from oil and gas fields for desert irrigation have received increasing...     

Aberrant guanosine triphosphate-beta-tubulin interaction in Alzheimer's disease

Guanosine triphosphate (GTP) is an absolute requirement for tubulin polymerization in situ. The nucleotide photoaffinity probe 8-azidoguanosine 5'-triphosphate (8N3GTP) has been shown to be a biological mimic of GTP in this system and, also, an effective active site probe of the exchangeable GTP binding site. Using [32P]8N3GTP we demonstrate that the exchangeable GTP site of the beta subunit of tubulin is available to added guanine nucleotide in normal aged brain homogenates, whereas it is variably unavailable in Alzheimer's diseased brain. Inability of 8N3GTP to photolabel beta tubulin appears to be associated with neurofibrillary tangle density. These results support the hypothesis that microtubule formation is abnormal in brains affected by Alzheimer's disease.     

A comparative analysis of cAMP-dependent protein kinase regulatory subunits in sea urchin and rat spermatozoa

8-Azido cAMP photoaffinity labeling of cAMP-dependent protein kinase regulatory subunits (R1 = 49 K;R2 = 55K) was done on spermatozoa from species lacking, and species containing an epididymis. Spermatozoa from sea urchin and trout contained only R1, while rat caudaepididymal spermatozoa contained both R1 and R2 subunits. This was established by the Mr value of the 8-azido cAMP photolabeled moieties, and a biochemical analysis based on the known differences of protein-nucleotide interactions of Type I and II cAMP-dependent protein kinases. Sea urchin and trout sperm R1 subunits were similar to mammalian sperm R1 subunits in co-migration on SDS-polyacrylamide gels and in both saturation and specificity of nucleotide binding. Calcium enhanced photoprobe binding to rat R1 and R2 subunits and to sea urchin R1 subunit without revealing a sea urchin R2 subunit. Likewise, phosphodiesterase incubation of sea urchin and trout spermatozoa prior to photolabeling did not reveal R2 subunits. These data suggest that the cAMP regulation of sperm physiology may require R1 subunit in species both with and without an epididymis. Further taxonomic study is necessary to determine whether evolutionary acquisition of the epididymis and internal fertilization may have created unique environments favoring the addition of sperm R2 regulatory subunits of cAMP-dependent protein kinase.     

The ultrastructure of the pharynx of Cosmocerca ornata (nematoda)

Summary The ultrastructure of the pharynx of Cosmocerca ornata is described. The tissues of the corpus can be differentiated into alternating radial and marginal regions on the basis of (i) their relative position in the corpus, (ii) the structure of the muscle fibres and (iii) cytoplasmic inclusions. The radial fibres contain two sizes of filaments, whereas the marginal fibres contain only one type. It is suggested that the former group are contractile and the latter supportive in function. The cuticle lining the triradiate lumen of the pharynx is simple in structure, whereas that lining the marginal canals is more complex. The marginal canal cuticle contains three layers and the centre one is composed of two types of rings which alternate in a vertical plane. Ring A is in continuity with the sub-cuticular cytoplasm and ring B contains alternating, radially arranged blocks of differing density. It is suggested that this arrangement serves to maintain the marginal canal in a distended state whilst the central lumen is contracted. Teeth are present at the junction of the marginal canal and central lumen, and together with those of the pharyngeal bulb, serve to filter solid material from the fluid contents. The wall of the pharyngeal bulb contains muscles and gland cells.     

Identification and phylogenetic analysis of orf viruses isolated from outbreaks in goats of Assam, a northeastern state of India

Two outbreaks of orf virus (ORFV) (a parapoxvirus) infection in goats, which occurred in Golaghat and Kamrup districts of Assam, a northeastern part of India, were investigated. The disease was diagnosed by standard virological and molecular techniques. The entire protein-coding region of B2L gene of two isolates were cloned and sequenced. Phylogenetic analysis based on B2L amino acid sequences showed that the ORFVs identified in these outbreaks were closely related to each other and both were closer to ORFV-Shahjahanpur 82/04 isolate from north India. The present study revealed that the precise characterization of the genomic region (B2L gene) might provide evidence for the genetic variation and movement of circulating ORFV strains in India.     

Role of Helicobacter pylori in gastric cancer: Updates

Helicobacter pylori (H. pylori) infection is highly prevalent in human, affecting nearly half of the world’s population; however, infection remains asymptomatic in majority of population. During its co-existence with humans, H. pylori has evolved various strategies to maintain a mild gastritis and limit the immune response of host. On the other side, presence of H. pylori is also associated with increased risk for the development of various gastric pathologies including gastric cancer (GC). A complex combination of host genetics, environmental agents, and bacterial virulence factors are considered to determine the susceptibility as well as the severity of outcome in a subset of individuals. GC is one of the most common cancers and considered as the third most common cause of cancer related death worldwide. Many studies had proved H. pylori as an important risk factor in the development of non-cardia GC. Although both H. pylori infection and GC are showing decreasing trends in the developed world, they still remain a major threat to human population in the developing countries. The current review attempts to highlight recent progress in the field of research on H. pylori induced GC and aims to provide brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment and transform the normal gastric epithelium to neoplastic one. This review also emphasizes on the mechanistic understanding of how colonization and various virulence attributes of H. pylori as well as the host innate and adaptive immune responses modulate the diverse signaling pathways that leads to different disease outcomes including GC.