Biochemical changes accompanying apoptotic cell death in retinoblastoma cancer cells treated with lipogenic enzyme inhibitors

Retinoblastoma (RB) is a malignant intra-ocular neoplasm that affects children (usually below the age of 5 years). In addition to conventional chemotherapy, novel therapeutic strategies that target metabolic pathways such as glycolysis and lipid metabolism are emerging. Fatty acid synthase (FASN), a lipogenic multi-enzyme complex, is over-expressed in retinoblastoma cancer. The present study evaluated the biochemical basis of FASN inhibition induced apoptosis in cultured Y79 RB cells. FASN inhibitors (cerulenin, triclosan and orlistat) significantly inhibited FASN enzyme activity (P < 0.05) in Y79 RB cells. This was accompanied by a decrease in palmitate synthesis (end-product depletion), and increased malonyl CoA levels (substrate accumulation). Differential lipid profile was biochemically estimated in neoplastic (Y79 RB) and non-neoplastic (3T3) cells subjected to FASN inhibition. The relative proportion of phosphatidyl choline to neutral lipids (triglyceride + total cholesterol) in Y79 RB cancer cells was found to be higher than the non-neoplastic cells, indicative of altered lipid distribution and utilization in tumor cells. FASN inhibitor treated Y79 RB and fibroblast cells showed decrease in the cellular lipids (triglyceride, cholesterol and phosphatidyl choline) levels. Apoptotic DNA damage induced by FASN inhibitors was accompanied by enhanced lipid peroxidation.     

Generalized transduction in Bacillus thuringiensis var. aizawai

J.R.M. INAL. V. KARUNAKARAN AND H.D. BURGES. 1992. Four temperate phages, ØHD67, ØHD130, ØHD228 and ØHD248, which were isolated from Bacillus thuringiensis H-serotype 7 strains, were tested for their ability to mediate transduction within H-serotype 7 and also between H-serotype 7 and 3a3b. The optimum conditions to facilitate transduction were determined. The four phages successfully mediated transduction within serotype 7 of all five auxotrophic markers tested and thus seem to have the ability to mediate generalized transduction. The phages also mediated transduction between H-serotype 7 and H-serotype 3a3b of 10 of 11 auxotrophic markers tested.     

φ20, A Temperate Bacteriophage Isolated from Bacillus anthracis Exists as a Plasmidial Prophage

This study describes the isolation of temperate B. anthracis phages, from 4 out of 20 B. anthracis strains screened, by use of the inducing agents mitomycin C and UV light. Phage φ20 isolated from B. anthracis Sterne 34F₂ (pXO1⁺ pXO2⁻) was shown to have double-stranded DNA of size 48756 bp and a restriction site map showing nine sites for enzymes BamHI, BglII, and SstI is included. The φ20 genome was found to exist as a plasmidial prophage and the phage itself to have a polyhedral head of diameter 65 nm and tail 217 nm long and 15 nm wide.     

Short-term exposure to dim light at night disrupts rhythmic behaviors and causes neurodegeneration in fly models of tauopathy and Alzheimer's disease

The accumulation and aggregation of phosphorylated tau proteins in the brain are the hallmarks for the onset of Alzheimer's disease (AD). In addition, disruptions in circadian rhythms (CRs) with altered sleep-wake cycles, dysregulation of locomotion, and increased memory defects have been reported in patients with AD. Drosophila flies that have an overexpression of human tau protein in neurons exhibit most of the symptoms of human patients with AD, including locomotion defects and neurodegeneration. Using the fly model for tauopathy/AD, we investigated the effects of an exposure to dim light at night on AD symptoms. We used a light intensity of 10 lux, which is considered the lower limit of light pollution in many countries. After the tauopathy flies were exposed to the dim light at night for 3 days, the flies showed disrupted CRs, altered sleep-wake cycles due to increased pTau proteins and neurodegeneration, in the brains of the AD flies. The results indicate that the nighttime exposure of tauopathy/AD model Drosophila flies to dim light disrupted CR and sleep-wake behavior and promoted neurodegeneration.     

M1 chlorophyll chimeras induced by different mutagens and their M2 chlorophyll mutation yields in rice

Studies with gamma rays, fast neutrons, and EMS treatments in rice showed higher frequency of M₁ chlorophyll chimeras in the EMS treatments, a correlation between the frequencies of M₁ chlorophyll chimeras and M₂ chlorophyll mutants, and a higher M₂ mutation frequency in the progeny of chimerical M₁ plants compared to those of normal-looking plants.     

New delay-interval-dependent stability criteria for switched Hopfield neural networks of neutral type with successive time-varying delay components

This paper deals with the problem of delay-interval-dependent stability criteria for switched Hopfield neural networks of neutral type with successive time-varying delay components. A novel Lyapunov–Krasovskii (L–K) functionals with triple integral terms which involves more information on the state vectors of the neural networks and upper bound of the successive time-varying delays is constructed. By using the famous Jensen’s inequality, Wirtinger double integral inequality, introducing of some zero equations and using the reciprocal convex combination technique and Finsler’s lemma, a novel delay-interval dependent stability criterion is derived in terms of linear matrix inequalities, which can be efficiently solved via standard numerical software. Moreover, it is also assumed that the lower bound of the successive leakage and discrete time-varying delays is not restricted to be zero. In addition, the obtained condition shows potential advantages over the existing ones since no useful term is ignored throughout the estimate of upper bound of the derivative of L–K functional. Using several examples, it is shown that the proposed stabilization theorem is asymptotically stable. Finally, illustrative examples are presented to demonstrate the effectiveness and usefulness of the proposed approach with a four-tank benchmark real-world problem.     

A mini-review on the effects of COVID-19 on younger individuals

Coronavirus disease 2019 (COVID-19) pandemic has uprooted our lives like never before since its onset in the late December 2019. The world has seen mounting infections and deaths over the past few months despite the unprecedented measures countries are implementing, such as lockdowns, social distancing, mask-wearing, and banning gatherings in large groups. Interestingly, young individuals seem less likely to be impacted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19. While the rate of transmission, symptom presentation, and fatality is lower in children than people from other age groups, they have been disproportionately affected by strict lockdown measures needed to curb viral spread. In this review, we describe the association between patient age and COVID-19, epidemiology of SARS-CoV-2 infection in children, psychological effects associated with lockdowns and school closures, and possible mechanisms underlying lower transmission rate of COVID-19 in children.     

Targeted genetics in Drosophila cell lines: Inserting single transgenes in vitro

A long-standing problem with analyzing transgene expression in tissue-culture cells is the variation caused by random integration of different copy numbers of transfected transgenes. In mammalian cells, single transgenes can be inserted by homologous recombination but this process is inefficient in Drosophila cells. To tackle this problem, our group, and the Cherbas group, used recombination-mediated cassette exchange (RMCE) to introduce single-copy transgenes into specific locations in the Drosophila genome. In both cases, ?C31 was used to catalyze recombination between its target sequences attP in the genome, and attB flanking the donor sequence. We generated cell lines de novo with a single attP-flanked cassette for recombination, whereas, Cherbas et al. introduced a single attP-flanked cassette into existing cell lines. In both approaches, a 2-drug selection scheme was used to select for cells with a single copy of the donor sequence inserted by RMCE and against cells with random integration of multiple copies. Here we describe the general advantages of using RMCE to introduce genes into fly cells, the different attributes of the 2 methods, and how future work could make use of other recombinases and CRISPR/Cas9 genome editing to further enable genetic manipulation of Drosophila cells in vitro.     

Isolation and propagation of phages naturally associated with the aizawai variety of Bacillus thuringiensis

This study describes the isolation of a phage, using mitomycin C and u.v. light, from each of four strains (HD67, HD130, HD228 and HD248) of Bacillus thuringiensis H-serotype 7 (var. aizawai). It also describes the isolation of two indicator strains (12.13 and HD 102) for these phages (φHD67, φHD130, φHD228 and φHD248) and the ideal conditions, using these indicator strains, for maximum phage production.