Defensive glands in Stylotermitidae (Blattodea, Isoptera).

The large abundance of termites is partially achieved by their defensive abilities. Stylotermitidae represented by a single extant genus, Stylotermes, is a member of a termite group Neoisoptera that encompasses 83% of termite species and 94% of termite genera and is characterized by the presence of the frontal gland. Within Neoisoptera, Stylotermitidae represents a species-poor sister lineage of all other groups. We studied the structure of the frontal, labral and labial glands in soldiers and workers of Stylotermes faveolus, and the composition of the frontal gland secretion in S. faveolus and Stylotermes halumicus. We show that the frontal gland is a small active secretory organ in soldiers and workers. It produces a cocktail of monoterpenes in soldiers, and some of these monoterpenes and unidentified proteins in workers. The labral and labial glands are developed similarly to other termite species and contribute to defensive activities (labral in both castes, labial in soldiers) or to the production of digestive enzymes (labial in workers). Our results support the importance of the frontal gland in the evolution of Neoisoptera. Toxic, irritating and detectable monoterpenes play defensive and pheromonal functions and are likely critical novelties contributing to the ecological success of these termites.

Cysteine proteases: Battling pathogenic parasitic protozoans with omnipresent enzymes.

Millions of people worldwide lie at the risk of parasitic protozoic infections that kill over a million people each year. The rising inefficacy of conventional therapeutics to combat these diseases, mainly due to the development of drug resistance to a handful of available licensed options contributes substantially to the rising burden of these ailments. Cysteine proteases are omnipresent enzymes that are critically implicated in the pathogenesis of protozoic infections. Despite their significance and druggability, cysteine proteases as therapeutic targets have not yet been translated into the clinic. The review presents the significance of cysteine proteases of members of the genera Plasmodium, Entamoeba, and Leishmania, known to cause Malaria, Amoebiasis, and Leishmaniasis, respectively, the protozoic diseases with the highest morbidity and mortality. Further, projecting them as targets for molecular tools like the CRISPR-Cas technology for favorable manipulation, exploration of obscure genomes, and achieving a better insight into protozoic functioning. Overcoming the hurdles that prevent us from gaining a better insight into the functioning of these enzymes in protozoic systems is a necessity. Managing the burden of parasitic protozoic infections pivotally depends upon the betterment of molecular tools and therapeutic concepts that will pave the path to an array of diagnostic and therapeutic applications.

Exploring insights of syntaxin superfamily proteins from Entamoeba histolytica: a prospective simulation, protein-protein interaction, and docking study.

Entamoeba histolytica (Eh), a parasitic protozoan and the causative agent of invasive Amoebiasis, invade the host tissue through an effective secretory pathway. There are several lines of evidence suggesting that amoebic trophozoite pore-forming complex amoebapore and a large class of proteases enzymes including rhomboid proteases, cysteine proteases, and metalloproteases are implicated in host tissue invasion. For successful delivery of these molecules/cargos, trophozoites heavily rely on sorting machinery from the endoplasmic reticulum, Golgi to plasma membrane. Although, sole secretion machinery in E. histolytica is not characterized yet. Therefore, here our aim is to understand the properties of key molecules N-ethylmaleimide-sensitive fusion protein attached to protein receptors (SNAREs) in E. histolytica. SNAREs proteins are an important component of the membrane-trafficking machinery and have been associated in a range of processes including vesicle tethering, fusion as well as specificity of vesicular transport in all eukaryotic cells. SNARE proteins are architecturally simple, categorized by the presence of one copy of a homologous coiled-coil forming motif. However, the structural information and protein-protein interaction study of Eh-associated syntaxin proteins are still not known. Here, we characterize the syntaxin 1 like molecule and VAMP from Eh through physiochemical profiling, modeling, atomistic simulation, protein-protein interaction, and docking approaches on the proteins containing SNARE and synaptobrevin domain. The modeled structures and the critical residues recognized through protein interaction and docking study may provide better structural and functional insights into these proteins and may aid in the development of newer diagnostic assays.

Rab GTPases take centre stage in understanding Entamoeba histolytica biology.

Rab GTPases constitute the largest subgroup in the Ras superfamily of GTPases. It is well established that different Rab GTPases are localized in discrete subcellular localization and regulate the membrane trafficking in nearly all eukaryotic cells. Rab GTPase diversity is often regarded as an expression of vesicular trafficking complexity. The pathogenic amoeba Entamoeba histolytica harbours 91 Rab GTPases which is the highest among the currently available genome sequences from the eukaryotic kingdom. Here, we review the current status of amoebic Rab GTPases diversity, unique biochemical and structural features and summarise their predicted regulators. We discuss how amoebic Rab GTPases are involved in cellular processes such as endocytosis, phagocytosis, and invasion of host cellular components, which are essential for parasite survival and virulence.

The exocyst complex and Rab5 are required for abscission by localizing ESCRT III subunits to the cytokinetic bridge.

Cytokinesis is the final step of cell division following chromosome segregation that generates two daughter cells. The conserved exocyst complex is required for scission of the intercellular cytokinetic bridge, although the molecular mechanisms it employs in this process are unclear. We identify and validate the early endocytic GTPase Rab5 as interacting with the exocyst complex in mammalian cells. Rab5 localizes in the cytokinetic bridge and on the midbody ring in a manner similar to the exocyst complex. Depletion of Rab5 led to delayed abscission. Caenorhabditis elegans orthologs of both exocyst complex subunits and Rab5 localize along the cleavage furrow and are required for cytokinesis in early embryos. Cytokinetic cells depleted of either Rab5 or the exocyst subunits Exoc3 and Exoc4 showed impaired deposition of the endosomal sorting complexes required for transport (ESCRT) III subunits CHMP2B and/or CHMP4B near the midbody ring. The study reveals an evolutionarily conserved role for the early endocytic marker Rab5 in cytokinetic abscission. In addition, it uncovers a key requirement of the exocyst and Rab5 for the delivery of components of the membrane-severing ESCRT III machinery to complete cytokinesis.

A Study to Compare the Efficacy of Platelet-rich Plasma and Minoxidil Therapy for the Treatment of Androgenetic Alopecia.

BACKGROUND: Androgenetic alopecia (AGA) is the most common cause of hair loss in men with limited treatment options. Platelet-rich plasma (PRP) therapy is one of the newer treatment options in the management of AGA which has shown promising results. AIMS AND OBJECTIVES: This study was aimed at comparing the clinical efficacy of PRP therapy with minoxidil therapy. MATERIALS AND METHODS: In the study, patients were randomized into two groups - Group A (given PRP therapy) and Group B (given minoxidil therapy). Both groups were followed up over a period of 6 months, and final analysis was done with the help of global photography, hair pull test, standardized hair growth questionnaire, patient satisfaction score; in addition, a comparison of platelet counts in PRP was done, to know that if a clinical correlation exists between platelet concentration and clinical improvement. A total of 40 patients clinically diagnosed with AGA were enrolled in the study with 20 patients in each group. Four patients from Group A (PRP) and six patients from Group B (minoxidil) could not complete the treatment for 6 months and were eventually excluded. RESULTS: At the end of 6 months, 30 patients were evaluated to compare the efficacy of intradermal PRP and topical minoxidil therapy. On global photography, Group A (PRP) was found to have a comparatively better outcome than Group B (minoxidil). In hair pull test, hair growth questionnaire, and patient satisfaction score, Group A was found to be better than Group B. Mean platelet count at baseline was 3.07 ± 0.5 lac/mm, 3 while platelet count in final PRP prepared was 12.4 ± 1.7 lac/mm, and patients with a higher platelet count in PRP had a much better clinical improvement compared to patients with a low platelet count in PRP. Side effects with PRP therapy were minimal with better results which may improve the compliance of the patient. CONCLUSION: PRP therapy can be a valuable alternative to topical minoxidil therapy in the treatment of AGA.

Heavy subunit of cell surface Gal/GalNAc lectin (Hgl) undergoes degradation via endo-lysosomal compartments in Entamoeba histolytica.

The human gut parasite Entamoeba histolytica uses a multifunctional virulence factor, Hgl, a cell surface transmembrane receptor subunit of Gal/GalNAc lectin that contributes to adhesion, invasion, cytotoxicity and immune response in the host. At present, the physiologic importance of Hgl receptor is mostly known for pathogenicity of E. histolytica. However, the molecular mechanisms of Hgl trafficking events and their association with the intracellular membrane transport machinery are largely unknown. We used biochemical and microscopy-based assays to understand the Hgl trafficking in the amoebic trophozoites. Our results suggest that the Hgl is constitutively degraded through delivery into amoebic lysosome-like compartments. Further, we also observed that the Hgl was significantly colocalized with amoebic Rab GTPases such as EhRab5, EhRab7A, and EhRab11B. While, we detected association of Hgl with all these Rab GTPases in early vacuolar compartments, only EhRab7A remains associated with Hgl till its transport to amoebic lysosome-like compartments.

Primary cutaneous mucoepidermal carcinoma.

Mucoepidermal carcinoma (MEC) is a tumour having mixed components of mucus secreting and epidermoid cells. Salivary glands are the the most common site of origin. Primary cutaneous MEC is a rare presentation. We report a primary cutaneous MEC in a 98-year-old woman presenting a noduloulcerative lesion over the dorsum of the nose. Histopathology of the tumour showed nests of epidermoid cells with glandular differentiation and mucin production. The diagnosis was confirmed by immunohistochemistry.

The Monomeric GTPase Rab35 Regulates Phagocytic Cup Formation and Phagosomal Maturation in Entamoeba histolytica.

One of the hallmarks of amoebic colitis is the detection of Entamoeba histolytica (Eh) trophozoites with ingested erythrocytes. Therefore, erythrophagocytosis is traditionally considered as one of the most important criteria to identify the pathogenic behavior of the amoebic trophozoites. Phagocytosis is an essential process for the proliferation and virulence of this parasite. Phagocytic cargo, upon internalization, follows a defined trafficking route to amoebic lysosomal degradation machinery. Here, we demonstrated the role of EhRab35 in the early and late phases of erythrophagocytosis by the amoeba. EhRab35 showed large vacuolar as well as punctate vesicular localization. The spatiotemporal dynamics of vacuolar EhRab35 and its exchange with soluble cytosolic pool were monitored by fluorescence recovery after photobleaching experiments. Using extensive microscopy and biochemical methods, we demonstrated that upon incubation with RBCs EhRab35 is recruited to the site of phagocytic cups as well as to the nascent phagosomes that harbor Gal/GalNAc lectin and actin. Overexpression of a dominant negative mutant of EhRab35 reduced phagocytic cup formation and thereby reduced RBC internalization, suggesting a potential role of the Rab GTPase in the cup formation. Furthermore, we also performed a phagosomal maturation assay and observed that the activated form of EhRab35 significantly increased the rate of RBC degradation. Interestingly, this mutant also significantly enhanced the number of acidic compartments in the trophozoites. Taken together, our results suggest that EhRab35 is involved in the initial stage of phagocytosis as well as in the phagolysosomal biogenesis in E. histolytica and thus contributes to the pathogenicity of the parasite.

Role of EhRab7A in phagocytosis of type 1 fimbriated E. coli by Entamoeba histolytica.

Entamoeba histolytica, the causative agent of amoebic colitis and liver abscess in human, ingests the intestinal bacteria and variety of host cells. Phagocytosis of bacteria by the amebic trophozoite has been reported to be important for the virulence of the parasite. Here, we set out to characterize different stages of phagocytosis of type 1 E. coli and investigated the role of a set of amoebic Rab GTPases in the process. The localizations of the Rab GTPases during different stages of the phagocytosis were investigated using laser scanning confocal microscopy and their functional relevance were determined using fluorescence activated cell sorter based assay as well as colony forming unit assay. Our results demonstrate that EhRab7A is localized on the phagosomes and involved in both early and late stages of type 1 E. coli phagocytosis. We further showed that the E. coli or RBC containing phagosomes are distinct from the large endocytic vacuoles in the parasite which are exclusively used to transport human holotransferrin and low density lipoprotein. Remarkably, type 1 E. coli uptake was found to be insensitive to cytochalasin D treatment, suggesting that the initial stage of E. coli phagocytosis is independent of the formation of actin filaments.

Realizing ferromagnetic ordering in SnO2 and ZnO nanostructures with Fe, Co, Ce ions.

We report the defects/vacancies that attribute to room temperature ferromagnetism in SnO2 in contrast to ZnO [Phys. Chem. Chem. Phys., 2016, 18, 5647], which has observed ferromagnetic ordering below room temperature, since both the systems involve similar dopant Fe, Co, and Ce ions. The Fe, Co, Ce doped SnO2 nanostructures were synthesized by a sol-gel process. The Rietveld refinement of the X-ray diffraction data detects a rutile SnO2 structure, with structural defects due to the deformation of the unit cell with doping. The pure, Fe and Co doped SnO2 have nanoparticle formation that is induced to nanorods with Ce co-doping. However, ZnO retained a nanorod-type shape with Fe and Co ions and changed to nanoparticles with Ce co-doping. The rutile SnO2 structure and defect formation with Fe, Co, and Ce ions is also confirmed with Raman vibrational modes. The observed lattice defects due to oxygen vacancies are shown by the photoluminescence study. The weak room temperature ferromagnetism is observed with Fe and Co ions in SnO2, which is enhanced with Ce ions. The zero field (ZFC) and field cooling magnetic measurements indicate an improvement in magnetization with a cusp in the ZFC curve at low temperature, observed due to an antiferromagnetic transition. It also induced variations in the magnetic coercive field due to the phenomenon of superparamagnetism, spin glasses, and magnetic clustered growth. This can be further confirmed with ac magnetic susceptibility measurements that show magnetic transitions as well as frequency dispersive and dependent behaviors of χ'(T)/χ''(T). However, the Fe, Co, Ce doped ZnO exhibit paramagnetic behavior at room temperature due to favorable antiferromagnetic interactions and have a ferromagnetic transition at low temperature with little ferromagnetic cluster growth.

Biophysical studies on calcium and carbohydrate binding to carbohydrate recognition domain of Gal/GalNAc lectin from Entamoeba histolytica: insights into host cell adhesion.

Entamoeba histolytica, an enteric parasite expresses a Gal/GalNAc-specific lectin that contributes to its virulence by establishing adhesion to host cell. In this study, carbohydrate recognition domain of Hgl (EhCRD) was purified and biophysical studies were conducted to understand the thermodynamic basis of its binding to carbohydrate and Ca(++) Here, we show that carbohydrate recognition domain (CRD) of the lectin binds to calcium through DPN motif. To decipher the role of calcium in carbohydrate binding and host cell adhesion, biophysical and cell-based studies were carried out. We demonstrated that the presence of the cation neither change the affinity of the lectin for carbohydrates nor alters its conformation. Mutation of the calcium-binding motif in EhCRD resulted in complete loss of ability to bind calcium but retained its affinity for carbohydrates. Purified EhCRD significantly diminished adhesion of the amebic trophozoites to Chinese Hamster Ovary (CHO) cells as well as triggered red blood cell agglutination. The calcium-binding defective mutant abrogated amebic adhesion to CHO cells similar to the wild-type protein, but it failed to agglutinate RBCs suggesting a differential role of the cation in these two processes. This study provides the first molecular description of the role of calcium in Gal/GalNAc mediated host cell adhesion.

Defects-assisted ferromagnetism due to bound magnetic polarons in Ce into Fe, Co:ZnO nanoparticles and first-principle calculations.

Zn0.94TM0.03Ce0.03O [Zn0.94Fe0.03Ce0.03O (ZFCeO) and Zn0.94Co0.03Ce0.03O (ZCCeO)] nanoparticles were synthesized by a sol-gel process. Elemental analysis of these nanoparticles detects the weight percentage of Zn, Co, Fe, Ce and O in each sample. The Rietveld refinement of the X-ray diffraction pattern obtains the occupancy of dopant atoms, Wurtzite ZnO structure, crystallinity and lattice deformation with doping. The Ce doping into ZFO and ZCO form nanoparticles than nanorods was observed in pure ZnO, ZFO and ZCO samples that described due to chemical and ionic behavior of Ce, Fe, Co and Zn ions. The Raman active modes have peak broadening, intensity changes and peak shifts with metal doping that induces lattice defects. Photoluminescence spectra show blue-shifts at near-band edges and defects that influence broad visible emission with Ce doping. An enhancement in ferromagnetism in the magnetic hysteresis at 5 K is measured. The zero-field cooling and field cooling at H = 500 Oe and T = 300-5 K could confirm antiferromagnetic interactions mediated by defect carriers. The bound magnetic polaron at defect sites is responsible for the observed ferromagnetism. The ac magnetic susceptibility measurements determine the antiferromagnetic to ferromagnetic transition with some magnetic clustered growth in the samples and reveal a frequency independent peak that shows the Neel temperature. Weak room temperature ferromagnetism and optical quenching in ZFCeO are described by valance states of Fe and Ce ions, respectively. Using first-principle calculations, we studied the occupancy of Ce (replacing Zn atoms) in the Wurtzite structure.

Strong Magnetoelectric Coupling of Pb1-xSrx(Fe0.012Ti0.988)O3 Nanoparticles.

Pb1-xSrx(Fe012Ti0.988)O3 (PSFT) nanoparticles were prepared by a chemical synthesis using polyvinyl alcohol as surfactant. X-ray diffraction pattern has been used to analyze the phase structure and average particles size. Transmission electron microscopy is used to confirm the nano size of the PSFT particles. The magnetoelectric (ME) coupling is observed at room temperature by measuring the ME coefficient (αE) as the function of applied dc magnetizing field under the influence of ac magnetic field of 2 Oe and frequency 800 Hz. The maximal value of αE is observed in PSFT3. The ME coupling is also studied by observing the variation of polarization hysteresis measured in the presence of zero and 0.2 T of external magnetic field.

Insights into endosomal maturation of human holo-transferrin in the enteric parasite Entamoeba histolytica: essential roles of Rab7A and Rab5 in biogenesis of giant early endocytic vacuoles.

The pathogenic amoeba Entamoeba histolytica is one of the causative agents of health hazards in tropical countries. It causes amoebic dysentery, colitis and liver abscesses in human. Iron is one of the essential nutritional resources for survival and chronic infection caused by the amoeba. The parasite has developed multiple ways to import, sequester and utilize iron from various iron-binding proteins from its host. In spite of its central role in pathogenesis, the mechanism of iron uptake by the parasite is largely unknown. Here, we carried out a systematic study to understand the role of some of the amoebic homologues of mammalian endocytic Rab GTPases (Rab5 and Rab21, Rab7A and Rab7B) in intracellular transport of human holo-transferrin by the parasite. Flow cytometry and quantitative microscopic image analysis revealed that Rab5 and Rab7A are required for the biogenesis of amoebic giant endocytic vacuoles (GEVs) and regulate the early phase of intracellular trafficking of transferrin. Rab7B is involved in the late phase, leading to the degradation of transferrin in the amoebic lysosome-like compartments. Using time-lapse fluorescence imaging in fixed trophozoites, we determined the kinetics of the vesicular transport of transferrin through Rab5-, Rab7A- and Rab7B-positive compartments. The involvement of Rab7A in the early phase of endocytosis by the parasite marks a significant divergence from its host in terms of spatiotemporal regulation by the Rab GTPases.