Proteomic analysis of zygote and ookinete stages of the avian malaria parasite Plasmodium gallinaceum delineates the homologous proteomes of the lethal human malaria parasite Plasmodium falciparum

Delineation of the complement of proteins comprising the zygote and ookinete, the early developmental stages of Plasmodium within the mosquito midgut, is fundamental to understand initial molecular parasite-vector interactions. The published proteome of Plasmodium falciparum does not include analysis of the zygote/ookinete stages, nor does that of P. berghei include the zygote stage or secreted proteins. P. gallinaceum zygote, ookinete, and ookinete-secreted/released protein samples were prepared and subjected to Multidimensional protein identification technology (MudPIT). Peptides of P. gallinaceum zygote, ookinete, and ookinete-secreted proteins were identified by MS/MS, mapped to ORFs (> 50 amino acids) in the extent P. gallinaceum whole genome sequence, and then matched to homologous ORFs in P. falciparum. A total of 966 P. falciparum ORFs encoding orthologous proteins were identified; just over 40% of these predicted proteins were found to be hypothetical. A majority of putative proteins with predicted secretory signal peptides or transmembrane domains were hypothetical proteins. This analysis provides a more comprehensive view of the hitherto unknown proteome of the early mosquito midgut stages of P. falciparum. The results underpin more robust study of Plasmodium-mosquito midgut interactions, fundamental to the development of novel strategies of blocking malaria transmission.     

Salicylic acid triggers genotoxic adaptation to methyl mercuric chloride and ethyl methane sulfonate, but not to maleic hydrazide in root meristem cells of Allium cepa L

Salicylic acid (SA), 0.01 mM, a signalling phytohormone, was tested for induction of adaptive response against genotoxicity of methyl mercuric chloride (MMCl), 0.013 mM; ethylmethane sulfonate (EMS), 2.5 mM, or maleic hydrazide (MH), 5 mM, in root meristem cells of Allium cepa. Induction of adaptive response to EMS by hydrogen peroxide (H2O2), 1 mM, and yet another secondary signal molecule was tested for comparison. Assessed by the incidence of mitoses with spindle and/or chromosome aberration and micronucleus, the findings provided evidence that SA-conditioning triggered adaptive response against the genotoxic-challenges of MMCl and EMS, but failed to do so against MH. H2O2, which is known to induce adaptive response to MMCl and MH, failed to induce the same against EMS in the present study. The findings pointed to the possible role of signal transduction in the SA-induced adaptive response to genotoxic stress that perhaps ruled out an involvement of H2O2.     

Lessons of slicing membranes: interplay of packing, free area, and lateral diffusion in phospholipid/cholesterol bilayers

We employ 100-ns molecular dynamics simulations to study the influence of cholesterol on structural and dynamic properties of dipalmitoylphosphatidylcholine bilayers in the fluid phase. The effects of the cholesterol content on the bilayer structure are considered by varying the cholesterol concentration between 0 and 50%. We concentrate on the free area in the membrane and investigate quantities that are likely to be affected by changes in the free area and free volume properties. It is found that cholesterol has a strong impact on the free area properties of the bilayer. The changes in the amount of free area are shown to be intimately related to alterations in molecular packing, ordering of phospholipid tails, and behavior of compressibility moduli. Also the behavior of the lateral diffusion of both dipalmitoylphosphatidylcholine and cholesterol molecules with an increasing amount of cholesterol can in part be understood in terms of free area. Summarizing, our results highlight the central role of free area in comprehending the structural and dynamic properties of membranes containing cholesterol.     

Atrial natriuretic peptide and thyroid hormones’ relation to plasma and heart calcium and magnesium concentrations of wistar rats exposed to cold and hot ambients

Plasma ANP (atrial natriuretic peptide), thyroid hormones, and calcium and magnesium levels as well as heart tissue calcium and magnesium concentrations were determined in male Wistar rats after exposure of 114 rats at low temperature (4°C) and 95 rats at high temperature (35–36°C) for 28 d. Plasma ANP, triiodothyronine (T₃), thyroxine (T₄), thyroid-stimulating hormone (TSH), free T₃, and free T₄ were estimated by radioimmunoassay, and plasma and heart tissue levels of Ca and Mg by flame atomic absorption spectrophotometry. Results were compared to a control group exposed at 20–22°C (76 rats). All the above parameters in control rats did not show statistically significant variations during the study. A significant increase of plasma ANP, T₃, T₄, Ca, and Mg concentrations developed during cold exposure, whereas a gradual decrease of plasma ANP, T₃, T₄, and Mg concentrations was revealed during hot exposure. A significant increase of heart tissue Mg concentrations developed during hot exposure. Results also indicate that plasma ANP and T₃ levels are proportionally related, whereas an inverse relationship exists between plasma ANP and T₃ levels and heart Mg concentrations, in both cold and hot exposed rats. In conclusion, ANP and thyroid hormones in relation to Ca and Mg play an important role in temperature adaptation.     

Aluminium triggers genotoxic adaptation to methyl mercuric chloride and ethyl methane sulfonate, but not to maleic hydrazide in plant cells in vivo

Non-toxic, conditioning doses of aluminium chloride were tested for induction of adaptive response to the genotoxic challenge doses of methyl mercuric chloride (MMCl), maleic hydrazide (MH) and ethyl methane sulfonate (EMS). Embryonic shoot cells of Hordeum vulgare and root meristem cells of Allium cepa were employed as the assay systems. Plant tissues fixed at different recovery hours following the challenge treatments with or without prior Al-conditioning were analyzed for cells with genotoxicity markers that include spindle and/or chromosome aberrations and micronuclei (MNC). The results provided evidence that Al(3+) triggered adaptive response that protected the plant cells from the genotoxicity of MMCl and EMS. Al(3+), however, failed to induce adaptive response against the genotoxicity of MH. A comparison of Al-induced adaptive response with that induced by heavy metals: Cd(2+), Cu(2+), Hg(2+), Ni(2+), Pb(2+), Zn(2+) and oxidative agents: hydrogen peroxide (H(2)O(2)) and paraquat (PQ) pointed to the similarity of Al-adaptive response to that of PQ rather than to other heavy metals or H(2)O(2). Al-induced adaptive response demonstrated in the present study to MMCl and EMS possibly involved antioxidant defense and DNA repair systems, respectively.     

In silico structural and functional modelling of Antifreeze protein (AFP) sequences of Ocean pout (Zoarces americanus, Bloch & Schneider 1801)

Antifreeze proteins (AFPs) are known to polypeptide components formed by certain plants, animals, fungi and bacteria which support to survive in sub-zero temperature. Current study highlighted the seven different antifreeze proteins of fish Ocean pout (Zoarces americanus), in which protein (amino acids sequence) were collected from National Centre for Biotechnology Information and finely characterized using several in silico tools. Such biocomputational techniques applied to figure out the physicochemical, functional and conformational characteristics of targeted AFPs. Multiple physicochemical properties such as Isoelectric Point, Extinction Coefficient and Instability Index, Aliphatic Index, Grand Average Hydropathy were calculated and analysed by ExPASy-ProtParam prediction web server. EMBOSS: pepwheel online tool was used to represent the protein sequences in a helical form. The primary structure analysis shows that most of the AFPs are hydrophobic in nature due to the high content of non-polar residues. The secondary structure of these proteins was calculated using SOPMA tool. SOSUI server and CYS_REC program also run for ideal prediction of transmembrane helices and disulfide bridges of experimental proteins respectively. The modelling of 3D structures of seven desired AFPs were executed by the homology modelling programmes; SWISS MODEL and ProSA web server. UCSF Chimera, Antheprot 3D, PyMOL and RAMPAGE were used to visualize and analysis of the structural variation of the predicted protein model. MEGA7.0.9 software used to know the phylogenetic relationship among these AFPs. These models offered excellent and reliable baseline information for functional characterization of the experimentally derived protein domain composition by using the advanced tools and techniques of Computational Biology.     

Rotaviral nonstructural protein 4 triggers dynamin‐related protein 1‐dependent mitochondrial fragmentation during infection

Dynamic equilibrium between mitochondrial fission and mitochondrial fusion serves as an important quality control system within cells ensuring cellular vitality and homeostasis. Viruses often target mitochondrial dynamics as a part of their obligatory cellular reprogramming. The present study was undertaken to assess the status and regulation of mitochondrial dynamics during rotavirus infection. Distinct fragmentation of mitochondrial syncytia was observed during late hours of RV (SA11, Wa, A5‐13) infection. RV nonstructural protein 4 (NSP4) was identified as the viral trigger for disrupted mitochondrial morphology. Severance of mitochondrial interconnections was found to be a dynamin‐related protein 1 (Drp1)‐dependent process resulting synergistically from augmented mitochondrial fission and attenuated mitochondrial fusion. Cyclin‐dependent kinase 1 was subsequently identified as the cellular kinase responsible for fission‐active Ser616 phosphorylation of Drp1. In addition to its positive role in mitochondrial fission, Drp1 also resulted in mitochondrial translocation of E3‐ubiquitin ligase Parkin leading to degradation of mitochondrial fusion protein Mitofusin 1. Interestingly, RV‐NSP4 was found to interact with and be involved in recruiting fission‐active pool of Serine 616 phosphoDrp1 (Ser616 pDrp1) to mitochondria independent of accessory adaptors Mitochondrial fission factor and Fission protein 1 (Fis1). Inhibition of either Drp1 or Ser616 pDrp1 resulted in significant decrease in RV‐NSP4‐induced intrinsic apoptotic pathway. Overall, this study underscores an efficient strategy utilised by RV to couple apoptosis to mitochondrial fission facilitating dissemination of viral progeny.     

Comprehensive profiling of functional attributes,virulence potential and evolutionary dynamics in mycobacterial secretomes

Mycobacterium is an interesting genus which not only includes intimidating pathogens, associated with severe devastations globally, but also comprises of non-pathogenic eco-friendly members that detoxify environmental pollutants. Secretory proteins of the mycobacterial communities are essential components which are firmly believed to facilitate proper cross-talk and apt communication with host cellular surroundings and environmental niche. Secretory elements also play vital roles in mycobacterial pathogenesis. In the present endeavor, an extensive profiling of mycobacterial secretomes, considering both pathogenic and non-pathogenic members, has been executed. Thorough analysis on amino acid composition and functional behavior of the mycobacterial secretory proteins has also been performed. In-depth scrutiny of biosynthetic cost of the secretory proteins with respect to the non-secretory ones indicated that the genus Mycobacterium strictly follows the policy of cost-minimization among the sets of imperative secretory proteins. Comprehensive assessment of potential virulence among the key secretory components signified that the pathogenic mycobacterial members possess a larger share of potentially virulent secretory elements in comparison to their non-pathogenic counterparts. Present analysis also revealed contrasted evolutionary features of the secretomes wherein secretory proteins were found to evolve faster than non-secretory proteins in mycobacterial pathogens but not in the concerned non-pathogens. Outcomes of present investigation promise to provide novel insights into the enigma of mycobacterial pathogenesis, bioremediation and adaptation in diverse niche and aid further scientific investigations associated with concerned research area.