Phylogeographical Structure in Mitochondrial DNA of Legume Pod Borer (Maruca vitrata) Population in Tropical Asia and Sub-Saharan Africa

This study was undertaken to assess the genetic diversity and host plant races of M. vitrata population in South and Southeast Asia and sub-Saharan Africa. The cytochrome c oxidase subunit 1 (cox1) gene was used to understand the phylogenetic relationship of geographically different M. vitrata population, but previous studies did not include population from Southeast Asia, the probable center of origin for Maruca, and from east Africa. Extensive sampling was done from different host plant species in target countries. Reference populations from Oceania and Latin America were used. An amplicon of 658 bp was produced by polymerase chain reaction, and 64 haplotypes were identified in 686 M. vitrata individuals. Phylogenetic analysis showed no difference among the M. vitrata population from different host plants. However, the results suggested that M. vitrata has formed two putative subspecies (which cannot be differentiated based on morphological characters) in Asia and sub-Saharan Africa, as indicated by the high pairwise F_ST values (0.44–0.85). The extremely high F_ST values (≥0.93) of Maruca population in Latin America and Oceania compared to Asian and African population seem to indicate a different species. On the continental or larger geographical region basis, the genetic differentiation is significantly correlated with the geographical distance. In addition, two putative species of Maruca, including M. vitrata occur in Australia, Indonesia and Papua New Guinea. The negative Tajima’s D and Fu’s F_S values showed the recent demographic expansion of Maruca population. The haplotype network and Automatic Barcode Gap Discovery analyses confirmed the results of phylogenetic analysis. Thus, this study confirmed the presence of three putative Maruca species, including one in Latin America, one in Oceania (including Indonesia) and M. vitrata in Asia, Africa and Oceania. Hence, the genetic differences in Maruca population should be carefully considered while designing the pest management strategies in different regions.     

Localization of protein-protein interactions in live cells using confocal and spectral imaging FRET microscopy

Microscopy has become an essential tool for cellular protein investigations. The development of new fluorescent markers such as green fluorescent proteins generated substantial opportunities to monitor protein-protein interactions qualitatively and quantitatively using advanced fluorescence microscope techniques including wide-field, confocal, multiphoton, spectral imaging, lifetime, and correlation spectroscopy. The specific aims of the investigation of protein dynamics in live specimens dictate the selection of the microscope methodology. In this article confocal and spectral imaging methods to monitor the dimerization of alpha enhancer binding protein (C/EBPalpha) in the pituitary GHFT1-5 living cell nucleus have been described. Also outline are issues involved in protein imaging using light microscopy techniques and the advantages of lifetime imaging of protein-protein interactions.     

Heterooligomerization between vasotocin and corticotropin-releasing hormone (CRH) receptors augments CRH-stimulated 3',5'-cyclic adenosine monophosphate production

In birds, ACTH release from the anterior pituitary gland during stress is controlled by CRH and arginine vasotocin (AVT). Using 5-wk-old male chicks, simultaneous iv injections of CRH and AVT were found to result in a greater than additive increase in plasma corticosterone levels compared with that obtained with individual administration of either peptide hormone. In order to investigate molecular mechanisms underlying this observation, the chicken CRH receptor (CRHR) and vasotocin VT2 receptor (VT2R) were fused to cyan and yellow fluorescent proteins and expressed in HeLa cells. The resulting CRHR and VT2R fusion proteins were expressed appropriately in the plasma membrane and were found to couple to downstream signal transduction pathways. Quantitative fluorescence resonance energy transfer (FRET) analysis was used to determine whether the CRHR and VT2R formed heterodimers. In the absence of CRH and AVT, the FRET efficiency was 15-18%, and the distance between receptors was 5-6 nm. Treatment of the cells that expressed both cyan fluorescent protein-CRHR and yellow fluorescent protein-VT2R with CRH or AVT alone did not lead to a significant change in the FRET efficiency. However, simultaneous addition of these hormones increased the efficiency of the FRET signal and decreased the distance between the two receptors. In HeLa cells expressing both CRHR and VT2R, treatment with CRH and AVT resulted in a significant increase in cAMP production over that with CRH alone, indicating that heterodimer formation may enhance the ability of the CRHR to activate downstream signal transduction.     

Pulmonary Artery Pseudoaneurysm in COVID-19-Associated Pulmonary Mucormycosis: Case Series and Systematic Review of the Literature

Mycopathologia - Literature on COVID-19-associated pulmonary mucormycosis (CAPM) is sparse. Pulmonary artery pseudoaneurysm (PAP) is an uncommon complication of pulmonary mucormycosis (PM), and...     

Serum glucose-regulated protein 78 (GRP78) levels in COVID-19-associated mucormycosis: results of a case–control study

Mycopathologia - In experimental models, the expression of glucose-regulated protein 78 (GRP78) in endothelial cells played a role in the pathogenesis of mucormycosis. However, the role of GRP78 in...     

The C‐terminal calcium‐sensitive disordered motifs regulate isoform‐specific polymerization characteristics of calsequestrin

Calsequestrin (CASQ) exists as two distinct isoforms CASQ1 and CASQ2 in all vertebrates. Although the isoforms exhibit unique functional characteristic, the structural basis for the same is yet to be fully defined. Interestingly, the C‐terminal region of the two isoforms exhibit significant differences both in length and amino acid composition; forming Dn‐motif and DEXn‐motif in CASQ1 and CASQ2, respectively. Here, we investigated if the unique C‐terminal motifs possess Ca²⁺‐sensitivity and affect protein function. Sequence analysis shows that both the Dn‐ and DEXn‐motifs are intrinsically disordered regions (IDRs) of the protein, a feature that is conserved from fish to man. Using purified synthetic peptides, we show that these motifs undergo distinctive Ca²⁺‐mediated folding suggesting that these disordered motifs are Ca²⁺‐sensitivity. We generated chimeric proteins by swapping the C‐terminal portions between CASQ1 and CASQ2. Our studies show that the C‐terminal portions do not play significant role in protein folding. An interesting finding of the current study is that the switching of the C‐terminal portion completely reverses the polymerization kinetics. Collectively, these data suggest that these Ca²⁺‐sensitivity IDRs located at the back‐to‐back dimer interface influence isoform‐specific Ca²⁺‐dependent polymerization properties of CASQ. © 2014 Wiley Periodicals, Inc. Biopolymers 103: 15–22, 2015.     

Multiwalled carbon nanotubes dispersed in carminic acid for the development of catalase based biosensor for selective amperometric determination of H(2)O(2) and iodate

We report the preparation of stable dispersion of multiwalled carbon nanotubes (MWCNTs) using carminic acid (CA) as a dispersing agent. The transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) results confirmed that MWCNT is well dispersed in CA aqueous solution and CA has been well adsorbed at MWCNT walls. Fourier transform infrared (FTIR) and UV-vis absorption spectra results also confirmed the adsorption of CA at MWCNT. To develop a highly selective amperometric biosensor for H(2)O(2) and iodate, the model enzyme catalase (CAT) was immobilized at CACNT modified glassy carbon electrode surface. The immobilized CAT exhibits well defined quasi reversible redox peaks at a formal potential (E°') of -0.559V in 0.05M pH 7 phosphate buffer solution (PBS). The proposed CAT/CACNT biosensor exhibits excellent amperometric response towards H(2)O(2) and iodate in the linear concentration range between 10μM to 3.2mM and 0.01-2.16mM. The sensitivity values are 287.98μAmM(-1)cm(-2) and 0.253mAmM(-1)cm(-2), respectively. Moreover, the developed CAT biosensor exhibits high affinity for H(2)O(2) and iodate with good selectivity.     

The MADS box gene, FOREVER YOUNG FLOWER, acts as a repressor controlling floral organ senescence and abscission in Arabidopsis

The ectopic expression of a MADS box gene FOREVER YOUNG FLOWER (FYF) caused a significant delay of senescence and a deficiency of abscission in flowers of transgenic Arabidopsis. The defect in floral abscission was found to be due to a deficiency in the timing of cell separation of the abscission zone cells. Down-regulation of INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) may contribute to the delay of the floral abscission in 35S:FYF flowers. FYF was found to be highly expressed in young flowers prior to pollination and was significantly decreased after pollination, a pattern that correlated with its function. Ethylene insensitivity in senescence/abscission and the down-regulation of ETHYLENE RESPONSE DNA-BINDING FACTOR 1 (EDF1) and EDF2, downstream genes in the ethylene response, in 35S:FYF Arabidopsis suggested a role for FYF in regulating senescence/abscission by suppressing the ethylene response. This role was further supported by the fact that 35S:FYF enhanced the delay of flower senescence/abscission in ethylene response 1 (etr1), ethylene-insensitive 2 (ein2) and constitutive triple response 1 (ctr1) mutants, which have defects in upstream genes of the ethylene signaling pathway. The presence of a repressor domain in the C-terminus of FYF and the enhancement of the delay of senescence/abscission in FYF+SRDX (containing a suppression motif) transgenic plants suggested that FYF acts as a repressor. Indeed, in FYF-DR+VP16 transgenic dominant-negative mutant plants, in which FYF was converted to a potent activator by fusion to a VP16-AD motif, the senescence/abscission of the flower organs was significantly promoted, and the expression of BOP2, IDA and EDF1/2 was up-regulated. Our data suggest a role for FYF in controlling floral senescence/abscission by repressing ethylene responses and regulating the expression of BOP2 and IDA in Arabidopsis.     

Structural and functional aspects of the myosin essential light chain in cardiac muscle contraction

The myosin essential light chain (ELC) is a structural component of the actomyosin cross-bridge, but its function is poorly understood, especially the role of the cardiac specific N-terminal extension in modulating actomyosin interaction. Here, we generated transgenic (Tg) mice expressing the A57G (alanine to glycine) mutation in the cardiac ELC known to cause familial hypertrophic cardiomyopathy (FHC). The function of the ELC N-terminal extension was investigated with the Tg-Δ43 mouse model, whose myocardium expresses a truncated ELC. Low-angle X-ray diffraction studies on papillary muscle fibers in rigor revealed a decreased interfilament spacing (≈ 1.5 nm) and no alterations in cross-bridge mass distribution in Tg-A57G mice compared to Tg-WT, expressing the full-length nonmutated ELC. The truncation mutation showed a 1.3-fold increase in I(1,1)/I(1,0), indicating a shift of cross-bridge mass from the thick filament backbone toward the thin filaments. Mechanical studies demonstrated increased stiffness in Tg-A57G muscle fibers compared to Tg-WT or Tg-Δ43. The equilibrium constant for the cross-bridge force generation step was smallest in Tg-Δ43. These results support an important role for the N-terminal ELC extension in prepositioning the cross-bridge for optimal force production. Subtle changes in the ELC sequence were sufficient to alter cross-bridge properties and lead to pathological phenotypes.     

A novel compound from the marine bacterium Bacillus pumilus S6-15 inhibits biofilm formation in gram-positive and gram-negative species

Biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. The aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant gram-positive and gram-negative biofilms. The bacterial extract (50 μg ml(-1)) of S6-01 (Bacillus indicus = MTCC 5559) showed 80-90% biofilm inhibition against Escherichia coli, Shigella flexneri, Proteus mirabilis and S6-15 (Bacillus pumilus = MTCC 5560) showed 80-95% biofilm inhibition against all the 10 tested organisms. Furthermore, they also reduced the hydrophobicity index and extracellular polymeric substances (EPS) production. Structural elucidation of the active principle in S6-15 using GC-MS, (1)H NMR, and (13)C NMR spectral data revealed it to be 4-phenylbutanoic acid. This is the first report of 4-phenylbutanoic acid as a natural product. The purified compound (10-15 μg ml(-1)) showed potential activity against a wide range of biofilms. This study for the first time, reports a novel anti-biofilm compound from a marine bacterium with wide application in medicine and the aquaculture industry.