Newly established tumourigenic primary human colon cancer cell lines are sensitive to TRAIL-induced apoptosis in vitro and in vivo

Most data on the therapeutic potential of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) as well as resistance to FAS ligand (FASL) in colorectal cancer have come from in vitro studies using cell lines. To gain a clearer understanding about the susceptibility of patient tumours to TRAIL and FASL, we derived primary human cancer epithelial cells from colon cancer patients. Characterisation of primary cultures PAP60 and MIH55 determined their highly proliferating advantage, transforming capability and tumorigenicity in vitro and in vivo. Although FASL treatment appeared to cause little apoptosis only in the PAP60 primary culture, increased apoptosis independent of p53 was observed in both primary PAP60 and MIH55 and control cell lines Caco-2, HT29 and DLD-1 after treatment with SuperKiller TRAIL. Expression analysis of death receptors (DR) in the original parental tumours, the primary cultures before and after engraftment as well as the mouse xenografts, revealed a significant upregulation of both DR4 and DR5, which correlated to differences in sensitivity of the cells to TRAIL-induced apoptosis. Treating patient tumour xenograft/SCID mouse models with Killer TRAIL in vivo suppressed tumour growth. This is the first demonstration of TRAIL-induced apoptosis in characterised tumorigenic primary human cultures (in vitro) and antitumour activity in xenograft models (in vivo)

Targeted disruption of the extracellular polymeric network of Pseudomonas aeruginosa biofilms by alginate oligosaccharides

Acquisition of a mucoid phenotype by Pseudomonas sp. in the lungs of cystic fibrosis (CF) patients, with subsequent over-production of extracellular polymeric substance (EPS), plays an important role in mediating the persistence of multi-drug resistant (MDR) infections. The ability of a low molecular weight (Mn=3200 g mol-1) alginate oligomer (OligoG CF-5/20) to modify biofilm structure of mucoid Pseudomonas aeruginosa (NH57388A) was studied in vitro using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) with Texas Red (TxRd®)-labelled OligoG and EPS histochemical staining. Structural changes in treated biofilms were quantified using COMSTAT image-analysis software of CLSM z-stack images, and nanoparticle diffusion. Interactions between the oligomers, Ca2+ and DNA were studied using molecular dynamics simulations (MDS), Fourier transform infrared spectroscopy (FTIR) and isothermal titration calorimetry (ITC). Imaging demonstrated that OligoG treatment (>0.5%) inhibited biofilm formation, demonstrating a significant reduction in both biomass and biofilm height (17.8 vs. 5.5 µm; P <0.05). TxRd®-labelled oligomers readily diffused into established (24 h) biofilms. OligoG treatment (≥2%) induced alterations in the EPS of established biofilms; significantly reducing the structural quantities of sugar residues, and extracellular (e)DNA (P <0.05) with a corresponding increase in nanoparticle diffusion (P<0.05) and antibiotic efficacy against established biofilms. ITC demonstrated an absence of rapid complex formation between DNA and OligoG and confirmed the interactions of OligoG with Ca2+ evident in FTIR and MDS. The ability of OligoG to diffuse into biofilms, potentiate antibiotic activity, disrupt DNA-Ca2+-DNA bridges and biofilm EPS matrix highlights its potential for the treatment of biofilm-related infections

Role Reversals in a Tri-Trophic Prey–Predator Interaction System: A Model-Based Study Using Deterministic and Stochastic Approaches

It is frequently observed that adult members of prey species sometimes use their predation mechanism on juvenile members of predator species. Ecological literature describes this phenomenon as prey–predator role reversal dynamics.Numerous authors have observed and described the biological development behind this feeding behaviour. However, the dynamics of this role reversal have hardly been illustrated in the literature in a precise way. In this regard, we formulated an ecological model using the standard prey–predator interactions, allowing for a reverse feeding mechanism. The mathematical model consisted of a three-species food-web structure comprising the common prey, intermediate predator, and top predator. Note that a role-reversal mechanism was observed between the intermediate and top predators based on the scarcity of the prey population. However, we observed the most critical parameters had a significant effect on this reverse feeding behaviour. The bifurcation analysis is the primary criterion for this identification. The proposed deterministic model is then extended to its stochastic analogue by allowing for environmental influences on the tri-trophic food web structure. The conditional moment approach is applied to obtain the equilibrium distribution of populations and their conditional moments in the system. The stochastic setup analysis also supports the stability of this food chain structure, with some restricted conditions. Finally, to facilitate the interpretation of our mathematical results, we investigated it using numerical simulations

Not Available

Collaborative works with ICMR-NICEDAn investigation was conducted to determine the distribution, virulence gene profile andphenotypes of Shiga toxin-producing Escherichia coli (STEC) strains within a dairy farm inKolkata, India by characterizing the STEC strains isolated from healthy dairy cow and calf stoolsamples, raw milk and farm floor swabs from July 2001 to March 2002. Primary screening bymultiplex-PCR detected stx1 and stx2, the common virulence genes of STEC, in 18.9 % of cowfaeces, 32.4 % of calf stool samples, 21.6 % of farm floor swabs and 4.5 % of raw milk samplesand viable STEC were recovered from 4.5, 9.9, 8.1 and 1.8% of the corresponding PCR-positivesamples. Strains harbouring stx1 (63.3 %) and hlyA (53.3 %) were frequently detected comparedto eae (13.3%). Most of the strains harboured similar sets of reported virulence genes commonamong isolates from diarrhoea patients. Most of the strains also exhibited multidrug resistance,sorbitol fermentation and produced enterohaemolysin. The randomly amplified polymorphicDNA–PCR (RAPD–PCR) profile of the STEC strains isolated from the farm milieu revealeddiverse banding patterns and clonal analysis demonstrated that the strains from different sourceswere not identical but showed some genetic relatedness. The study demonstrates the potential ofdairy farm for housing virulent STEC. (3) (PDF) Dairy farm investigation on Shiga toxin-producing Escherichia coli (STEC) in Kolkata, India with emphasis on molecular characterization. Available from: https://www.researchgate.net/publication/7694281_Dairy_farm_investigation_on_Shiga_toxin-producing_Escherichia_coli_STEC_in_Kolkata_India_with_emphasis_on_molecular_characterization#fullTextFileContent [accessed Apr 18 2023].ICMR-New Delh