Host-induced silencing of Mi-msp-1 confers resistance to root-knot nematode Meloidogyne incognita in eggplant

RNA interference (RNAi)-based host-induced gene silencing (HIGS) is emerging as a novel, efficient and target-specific tool to combat phytonematode infection in crop plants. Mi-msp-1, an effector gene expressed in the subventral pharyngeal gland cells of Meloidogyne incognita plays an important role in the parasitic process. Mi-msp-1 effector is conserved in few of the species of root-knot nematodes (RKNs) and does not share considerable homology with the other phytonematodes, thereby making it a suitable target for HIGS with minimal off-target effects. Six putative eggplant transformants harbouring a single copy RNAi transgene of Mi-msp-1 was generated. Stable expression of the transgene was detected in T₁, T₂ and T₃ transgenic lines for which a detrimental effect on RKN penetration, development and reproduction was documented upon challenge infection with nematode juveniles. The post-parasitic nematode stages extracted from the transgenic plants showed long-term RNAi effect in terms of targeted downregulation of Mi-msp-1. These findings suggest that HIGS of Mi-msp-1 enhances nematode resistance in eggplant and protect the plant against RKN parasitism at very early stage.

     

The mechanism of phosphatidylcholine‐induced interference of PAP (248‐286) aggregation

Seminal amyloids are well known for their role in enhancing HIV infection. Among all the amyloidogenic peptides identified in human semen, PAP_248‐286 was found to be the most active and was termed as semen‐derived enhancer of viral infection (SEVI). Although amyloidogenic nature of the peptide is mainly linked with enhancement of the viral infection, the most active physiological conformation of the aggregated peptide remains inconclusive. Lipids are known to modulate aggregation pathway of a variety of proteins and peptides and constitute one of the most abundant biomolecules in human semen. PAP_248‐286 significantly differs from the other known amyloidogenic peptides, including Aβ and IAPP, in terms of critical concentration, surface charge, fibril morphology, and structural transition during aggregation. Hence, in the present study, we aimed to assess the effect of a lipid, 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC), on PAP_248‐286 aggregation and the consequent conformational outcomes. Our initial observation suggested that the presence of the lipid considerably influenced the aggregation of PAP_248‐286. Further, ZDOCK and MD simulation studies of peptide multimerization have suggested that the hydrophobic residues at C‐terminus are crucial for PAP_248‐286 aggregation and are anticipated to be major DOPC‐interacting partners. Therefore, we further assessed the aggregation behaviour of C‐terminal (PAP_273‐286) fragment of PAP_248‐286 and observed that DOPC possesses the ability to interfere with the aggregation behaviour of both the peptides used in the current study. Mechanistically, we propose that the presence of DOPC causes considerable inhibition of the peptide aggregation by interfering with the peptide's disordered state to β‐sheet transition.     

DNA-enzyme-mediated cleavage of human immunodeficiency virus type 1 Gag RNA is significantly augmented by antisense-DNA molecules targeted to hybridize close to the cleavage site

DNA-enzymes (Dzs) usually cleave short synthetic target RNAs very efficiently, but this activity diminishes significantly when tested on full-length RNAs, primarily because of the rigid secondary structures near the target sequence. We identified two Dzs, one each for 81-17 and 10-23 Dz, which cleaved the human immunodeficiency virus type 1 (HIV-1) Gag RNA poorly. We sought to use short oligodeoxynucleotides (ODNs) with the hope that it will facilitate Dz-mediated cleavage. The efficiencies of several ODNs were analyzed for their ability to augment the 8-17 Dz-mediated cleavage. We observed that ODNs that hybridized close to 5' and 3' ends of the target sequence were able to enhance significantly 8-17 Dz-mediated cleavage activity in a dose-dependent manner. The same was true for 10-23 Dz with ODNs that hybridized close to the target site. Thus, it was possible to enhance significantly the cleavage activity of poorly cleaving HIV-1 Gag-specific Dzs by using sequence-specific ODNs. This combination of antisense and catalytic Dz will, in principle, result in more effective gene suppression that could be exploited for therapeutic purposes.     

Animal cell differentiation patterns suppress somatic evolution

Cell differentiation in multicellular organisms has the obvious function during development of creating new cell types. However, in long-lived organisms with extensive cell turnover, cell differentiation often continues after new cell types are no longer needed or produced. Here, we address the question of why this is true. It is believed that multicellular organisms could not have arisen or been evolutionarily stable without possessing mechanisms to suppress somatic selection among cells within organisms, which would otherwise disrupt organismal integrity. Here, we propose that one such mechanism is a specific pattern of ongoing cell differentiation commonly found in metazoans with cell turnover, which we call “serial differentiation.” This pattern involves a sequence of differentiation stages, starting with self-renewing somatic stem cells and proceeding through several (non–self-renewing) transient amplifying cell stages before ending with terminally differentiated cells. To test the hypothesis that serial differentiation can suppress somatic evolution, we used an agent-based computer simulation of cell population dynamics and evolution within tissues. The results indicate that, relative to other, simpler patterns, tissues organized into serial differentiation experience lower rates of detrimental cell-level evolution. Self-renewing cell populations are susceptible to somatic evolution, while those that are not self-renewing are not. We find that a mutation disrupting differentiation can create a new self-renewing cell population that is vulnerable to somatic evolution. These results are relevant not only to understanding the evolutionary origins of multicellularity, but also the causes of pathologies such as cancer and senescence in extant metazoans, including humans.     

In vitro and in silico molecular interaction of multiphase nanoparticles containing inositol hexaphosphate and jacalin: Therapeutic potential against colon cancer cells (HCT-15)

Inositol hexaphosphate (IP6) is a natural constituent found in almost all cereals and legumes. It is known to cause numerous antiangiogenic manifestations. Notwithstanding its great potential, it is underutilized due to the chelation and rapid excretion from the body. Jacalin is another natural constituent obtained from seeds of jackfruit and can target disaccharides overexpressed in tumor cells. The current study was in-quested to develop and evaluate a surface-modified gold nanoparticulate system containing IP6 and jacalin which may maximize the apoptotic effect of IP6 against HCT-15 cell lines. IP6 loaded jacalin-pectin-gold nanoparticles (IJP-GNPs) were developed through reduction followed by incubation method. The developed formulation was tested for various in vitro and in silico studies to investigate its potential. HCT-15 cells when exposed to IJP-GNP resulted in significant apoptotic effects in dose as well as time-dependent manner, as measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, micronucleus, and reactive oxygen species assay. IJP-GNP displayed cell cycle arrest at the G0/G1 phase. To further explore the mechanism of chemoprevention, in silico studies were performed. The docking results revealed that the interactive behavior of IP6, P-GNP, and jacalin could target and inhibit the tumor formation activity, supported by in vitro studies. Taken together, all the findings suggested that IP6 loaded nanoparticles may increase the hope of future drug delivery strategy for targeting colon cancer.     

A double blind randomized controlled trial to evaluate the efficacy of green tea in gingivitis

Gingivitis is the most common form of oral disease especially among patients undergoing fixed orthodontic treatment. Green tea, which is extensively used in Asian countries, can help to improve the overall gingival health, which can be assessed by using the gingival indices. Evaluation of the effectiveness of green tea on the gingival health of patients undergoing Orthodontic treatment is of interest. 40 otherwise healthy patients undergoing fixed orthodontic treatment were randomly divided in two groups namely (1) study group and (2) control group. Gingival indices were scored for all the patients. Study group was given mouth rinse with green tea extract and control group was given placebo with no green tea extract. Gingival indices were measured for all the patients after 21 days. Mann Whitney U test and Wilcoxon test was used for statistical analysis. The gingival indices scoring in which the values before and after the use of mouthwash were compared. The p value was found to be statistically significant (p<0.05) in study group. But in control group statistical significant could not be reached.     

Substance P binding sites in the nucleus tractus solitarius of the cat

Substance P binding sites in the nucleus tractus solitarius were visualized with receptor autoradiography using Bolton-Hunter [¹²⁵I]substance P. Substance P binding sites were found to have distinct patterns within the cat nucleus tractus solitarius. The majority of substance P binding sites were present in the medial, intermediate and the peripheral rim of the parvocellular subdivisions. Lower amounts of substance P binding sites were present in the commissural, ventrolateral, interstitial and dorsolateral subdivisions. No substance P binding sites were present in the central region of the parvocellular subdivision or the solitary tract. The localization of substance P binding sites in the nucleus tractus solitarius is very similar to the patterns of substance P immunoreactive fibers previously described for this region. Results of this study add further support for a functional role of substance P in synaptic circuits of the nucleus tractus solitarius.     

Incidence of lab-confirmed dengue fever in a pediatric cohort in Delhi,India

BackgroundOur aim was to estimate the overall and age-specific incidence of lab-confirmed dengue fever using ELISA based assays among children 6 months to 15 years in Delhi.MethodsWe enrolled a cohort of 984 children aged 6 months to <14 years in South Delhi and followed-up weekly for fever for 24 months or till 15 completed years of child-age. Households of the enrolled children were geo-tagged. NS1, IgM and IgG assays were conducted using ELISA method to confirm dengue fever in children with ≥3 consecutive days of fever. Molecular typing was done in a subset of NS1 positive cases to identify the circulating serotypes.Principal findingsWe had a total of 1953 person-years (PY) of follow up. Overall, there were 4208 episodes of fever with peaks during June to November. The overall incidence (95%CI) of fever was 215/100 PY (209 to 222). A total of 74/1250 3-day fever episodes were positive for acute dengue fever (NS1 and/or IgM positive). The overall incidence (95%CI) of acute dengue fever was 37.9 (29.8 to 47.6) per 1000 PY; highest among children aged 5 to 10 years (50.4 per 1000 PY, 95% CI 36.5 to 67.8). Spatial autocorrelation analysis suggested a clustering pattern for the dengue fever cases (Moran’s Index 0.35, z-score 1.8, p = 0.06). Dengue PCR was positive in 16 of the 24 specimens tested; DEN 3 was the predominant serotype identified in 15/24 specimens.ConclusionsWe found a high incidence of dengue fever among under 15-year children with clustering of cases in the community. DEN 3 was the most commonly circulating strain encountered. The findings underscore the need for development of affordable pre-vaccination screening strategy as well as newer dengue vaccines for young children while continuing efforts in vector control.     

Smad and p38-MAPK signaling mediates apoptotic effects of transforming growth factor-beta1 in human airway epithelial cells

Transforming growth factor-beta1 (TGF-beta1) belongs to a family of multifunctional cytokines that regulate a variety of biological processes, including cell differentiation, proliferation, and apoptosis. The effects of TGF-beta1 are cell context and cell cycle specific and may be signaled through several pathways. We examined the effect of TGF-beta1 on apoptosis of primary human central airway epithelial cells and cell lines. TGF-beta1 protected human airway epithelial cells from apoptosis induced by either activation of the Fas death receptor (CD95) or by corticosteroids. This protective effect was blocked by inhibition of the Smad pathway via overexpression of inhibitory Smad7. The protective effect is associated with an increase in the cyclin-dependent kinase inhibitor p21 and was blocked by the overexpression of key gatekeeper cyclins for the G1/S interface, cyclins D1 and E. Blockade of the Smad pathway by overexpression of the inhibitory Smad7 permitted demonstration of a TGF-beta-mediated proapoptotic pathway. This proapoptotic effect was blocked by inhibition of the p38 MAPK kinase signaling with the inhibitor SB-203580 and was associated with an increase in p38 activity as measured by a kinase assay. Here we demonstrate dual signaling pathways involving TGF-beta1, an antiapoptotic pathway mediated by the Smad pathway involving p21, and an apoptosis-permissive pathway mediated in part by p38 MAPK.