Chemistry and Biochemistry Aspects of the 4-Hydroxy-2,3-trans-nonenal

4-hydroxy-2,3-trans-nonenal (C9H16O2), also known as 4-hydroxy-2E-nonenal (C9H16O2; HNE) is an α,β-unsaturated hydroxyalkenal. HNE is a major aldehyde, formed in the peroxidation process of ω-6 polyunsaturated fatty acids (ω-6 PUFAs), such as linoleic and arachidonic acid. HNE is not only harmful but also beneficial. In the 1980s, the HNE was regarded as a “toxic product of lipid peroxidation” and the “second toxic messenger of free radicals”. However, already at the beginning of the 21st century, HNE was perceived as a reliable marker of oxidative stress, growth modulating factor and signaling molecule. Many literature data also indicate that an elevated level of HNE in blood plasma and cells of the animal and human body is observed in the course of many diseases, including cancer. On the other hand, it is currently proven that cancer cells divert to apoptosis if they are exposed to supraphysiological levels of HNE in the cancer microenvironment. In this review, we briefly summarize the current knowledge about the biological properties of HNE.

The Central Role of Multiple P450 Genes and Their Co-factor CPR in the Development of Permethrin Resistance in the Mosquito Culex quinquefasciatus

Mosquitoes’ increasing resistance to insecticides is becoming a major threat for control efforts worldwide. Multiple P450 genes that are up-regulated in permethrin resistant strains of Culex quinquefasciatus have been linked to the development of resistance. In the current study, we characterized the function of six P450 genes, CYP6P14, CYP6BZ2, CYP9J33, CYP9J34, CYP9J40, and CYP9J45, that are overexpressed in the permethrin resistant Culex mosquitoes and showed their capability in metabolism of permethrin. These six P450 genes can convert 3-phenoxybenzoic alcohol (PBCHO) to a less toxic product, 3-phenoxybenzoic acid (PBCOOH), indicating that these P450s play an important role in permethrin degradation pathways. Although we know multiple P450 genes are over-expressed in permethrin resistant Culex mosquitoes, it remains to be seen whether cytochrome P450-reductase (CPR) gene that are co-overexpressed with P450 genes in permethrin resistant mosquitoes do indeed serve as a resistance mechanism. An in-depth investigation of the expression of CPR gene in resistant mosquitoes was conducted in permethrin resistant mosquitoes. The finding of CPR gene overexpression in permethrin resistant mosquitoes suggested the importance of co-overexpression of multiple P450 genes with their obligatory electron donor CPR in the complex detoxification system, boosting the metabolism of permethrin and hence the development of permethrin resistance in Cx. quinquefasciatus.

Genetic polymorphism of ALDH2 in Indonesia’s Minang ethnic

Background: In some people, acetaldehyde, a toxic product from ethanol oxidation, cannot be oxidized to acetate. The excess of acetaldehyde could cause facial flushing, dizziness, and hypertension when they consume ethanol. This ethanol sensitivity is caused by a deficiency of ALDH2. Objective: This study aims to analyze and count the polymorphism frequency of the ALDH2 gene in Indonesia’s Minang ethnic. Methods: DNA samples were taken randomly from hair bulbous of 60 subjects (male and female, 3rd generation). A nested polymerase chain reaction was conducted to amplify the ALDH2 in the samples. Afterward, restriction fragment length polymorphism (RFLP) was conducted to the amplicons using the EcoRI restriction enzyme. The measured parameters were the distribution of the wildtype, atypical homozygote, and heterozygote. Results: Results showed that out of 60 subjects, 53.33% have an atypical homozygote gene (subjects prone to hypersensitive to alcohol), 28.33% have a heterozygote gene, and 18.33% have a wildtype gene. The frequency of the atypical alleles in Minang ethnic is 0.675. Conclusion: The atypical ALDH2 allele was much higher than the normal ALDH2 allele, in which most participants have atypical homozygote ALDH2, suggesting the samples are sensitive to alcohol.

BIOPLASTIC MADE OF ORANGE PEELS

This study uses orange peel waste to create a biopolymer that can be used for different purposes. In order to achieve this, we evaluated various technologies for the production of the biopolymer, and tried to design the most environmentally friendly process possible. One of the reasons why this bioplastic should be manufactured is to participate in the replacement of common environmental hazardous plastic, which has been banned in many places. On the other hand, using orange peel as the main ingredient is an alternative and gives value to an organic waste that has limited use in circular economy solutions. In this research we present a methodology to create a bioplastic of orange peels. As a result, we obtained a biodegradable, flexible and resistant material to be used in the manufacture of containers, utensils, etc. In addition, it is a material that, given the raw materials used, is considered GRAS (Generally Recognized As Save), implying a non-toxic product that is safe for the consumer.

Transport Proteins Enabling Plant Photorespiratory Metabolism

Photorespiration (PR) is a metabolic repair pathway that acts in oxygenic photosynthetic organisms to degrade a toxic product of oxygen fixation generated by the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase. Within the metabolic pathway, energy is consumed and carbon dioxide released. Consequently, PR is seen as a wasteful process making it a promising target for engineering to enhance plant productivity. Transport and channel proteins connect the organelles accomplishing the PR pathway—chloroplast, peroxisome, and mitochondrion—and thus enable efficient flux of PR metabolites. Although the pathway and the enzymes catalyzing the biochemical reactions have been the focus of research for the last several decades, the knowledge about transport proteins involved in PR is still limited. This review presents a timely state of knowledge with regard to metabolite channeling in PR and the participating proteins. The significance of transporters for implementation of synthetic bypasses to PR is highlighted. As an excursion, the physiological contribution of transport proteins that are involved in C4 metabolism is discussed.

Using Daphnia magna Straus to monitor toxicity of sustainable oil sludge bio-phytoremediation

Oil sludge (OS) is the toxic product of various oil refinery processes. Oil sludge biophytoremediation is sustainable remediation efforts were conducted to reduce OS toxicity level and they also need to be monitored through toxicity test. In this study, the toxicants were OS postbiophytoremediation for 24 months (OS24) and 40 months (OS40), and were tested to Daphnia magna. The toxicity test consisted of Range Finding Test, acute and chronic toxicity test. The purpose of this research is to obtain the LC50 value of each OS and the chronic effects shown by D. magna. The method in this study was experimental with Completely Randomized Design (CRD). The LC50-96 hours values were calculated from 50% of dead individuals while D. magna reproduction was calculated from the number of neonates (offspring) produced within three weeks. The LC50 of OS24 and OS40 were 0.042 ppm and 0.366 ppm respectively. Both were categorized as ‘extremely toxic’ refer to Swan, 1994, observed chronic effects were reproduction delays and a decrease in the number of neonates.

The murburn precepts for photoreception

Murburn concept is a redox mechanistic scheme involving interactive equilibriums of discretized or organized proteins/substrates molecules, unbound ions and radicals (or reactive species); which may afford selective/specific electron transfers, particularly at phospholipid interfaces. Earlier, we have applied murburn concept to provide parsimonious explanations (grounded in thermodynamics and kinetics) for various physiological/bioenergetic routines like xenobiotic metabolism, unusual dose responses, aerobic respiration, thermogenesis, homeostasis, trans-membrane potential, oxygenic photosynthesis, etc. While proposing the murburn model for photophosphorylation, we had projected that the murburn mechanism could also be relevant for photoreception physiology. Herein, we expand on this aspect and present the basic scheme and evidence in support for the murburn model of photoreception, with retinal/opsin as the salient photon-impingement response-transducing element. In alignment with our earlier murburn schemes, we propose that diffusible reactive oxygen species (DROS, as exemplified by superoxide, which is currently deemed a toxic product of all-trans retinal and NADPH oxidase interactions) is produced in rod/cone cells upon photoactivation and it plays a crucial role in the visual cycle. This is supported by the fact that layers of photoreceptive neural cells precede the rod/cone cells (with respect to the presentation to oncoming light ray/photon), there exists high oxygen demand in retina, copious ROS are detected in functional retina, NAD(P)H/reductase is involved in the cycle, events occur at sub-micrometer dimensioned phospholipid disks stacked to stabilize DROS and minimize free protons (quite like the thylakoids that harbor carotenoids in chloroplasts and cyanobacteria), etc. In the new scheme, photo-electric activation leads to charge separation and hyperpolarization. This electro-chemical signaling serves is the front-runner to a trigger for action potential relay along a neuron and the superoxide mediated phosphorylation of GDP bound to transducin serves as the initiator of signal transduction cascade. The newly proposed scheme allows a facile electrical connectivity of the retina-photoreceptors with the brain via the optic nerve, and is anatomically correlated with the structure and resolution or retina, and is kinetically viable.

Truncated Expression of a Carboxypeptidase A from Bovine Improves Its Enzymatic Properties and Detoxification Efficiency of Ochratoxin A

Ochratoxin A (OTA) is a toxic secondary metabolite produced mainly by Penicillium spp. and Aspergillus spp. and commonly found in foodstuffs and feedstuffs. Carboxypeptidase A (CPA) can hydrolyze OTA into the non-toxic product ochratoxin α, with great potential to realize industrialized production and detoxify OTA in contaminated foods and feeds. This study constructed a P. pastoris expression vector of mature CPA (M-CPA) without propeptide and signal peptide. The results showed that the degradation rate of OTA by M-CPA was up to 93.36%. Its optimum pH was 8, the optimum temperature was 40 °C, the value of Km was 0.126 mmol/L, and the maximum reaction rate was 0.0219 mol/min. Compared with commercial CPA (S-CPA), the recombinant M-CPA had an improve stability, for which its optimum temperature increased by 10 °C and stability at a wide range pH, especially at pH 3–4 and pH 11. M-CPA could effectively degrade OTA in red wine. M-CPA has the potential for industrial applications, such as can be used as a detoxification additive for foods and feeds.