Microelectrode glucose biosensor based on nanoporous platinum/graphene oxide nanostructure for rapid glucose detection of tomato and cucumber fruits

Microelectrode glucose biosensor based on three-dimensional hybrid nanoporous platinum/graphene oxide nanostructure was developed for rapid glucose detection of tomato and cucumber fruits. The nanostructure was fabricated by a two-step modification method on microelectrode for loading a larger amount of glucose oxidase. The nanoporous structure was prepared on the surface of the platinum microelectrode by electrochemical etching, and then graphene oxide was deposited on the prepared nanoporous electrode by electrochemical deposition. The nanoprorous platinum/graphene oxide nanostructure had the advantage of improving the effective surface area of the electrode and the loading quantity of glucose oxidase. As a result, the biosensor achieved a wide range of 0.1-20.0 mM in glucose detection, which had the ability to accurately detect the glucose content. It was found that the three-dimensional hybrid nanostructure on the electrode surface realized the rapid direct electrochemistry of glucose oxidase. Therefore, the biosensor achieved high glucose detection sensitivity (11.64 μA mM -1cm -2), low detection limit (13 μM) and rapid response time (reaching 95% steady-state response within 3 seconds), when calibrating in glucose standard solution. In agricultural application, the as-prepared biosensor was employed to detect the glucose concentration of tomato and cucumber samples. The results showed that the relative deviation of this method was less than 5% when compared with that of HPLC, implying high accuracy of the presented biosensor in glucose detection in plants.

Optical properties of honey: FTIR spectroscopy and refractometry

115 samples of honey of various botanical types, geographical origin and harvest year (2019– 2021) were analysed using attenuated total reflection infrared spectroscopy of impaired total reflection, refractometry and biochemical analysis. Initial honey samples in liquid and crystallised states were investigated. Crystalline D-glucopyranose (glucose), D-fructopyranose (fructose), their 40% solutions and invert sugar were used as auxiliary substances. Biochemical analysis was used to determine the glucose content in honey samples. Based on the obtained data, a relationship between the results of biochemical analysis and refractometry (refractive index, the content of invert sugars, humidity) was established. We deduced equations that allow the content of glucose and fructose in honey to be evaluated by the refractive index. Studying honey by IR spectroscopy showed that all investigated samples, regardless of the botanical and geographical origins, can be classified into three groups dominated by: I – glucose, II – fructose and III – mixed, with a close content of two monosaccharides. This allowed the bands characteristic of α- and β-pyranose forms of glucose and fructose to be identified, as well as the nature of their changes depending on the ratio of both monosaccharides in honey as a result of their crystallisation to be assessed. It is noted that the ratio of monosaccharides determines not only the stability of the liquid crystal structure and crystallisation rate in honey but also their optical, biochemical and nutritional properties, which are important for the preferred use of honey in medical and pharmacopoeial practice, dietetics and cosmetology.

Celastrol Protects against Cerebral Ischemia/Reperfusion Injury in Mice by Inhibiting Glycolysis through Targeting HIF-1α/PDK1 Axis

Cerebral ischemia/reperfusion (I/R) injury is closely related to dysfunctional glucose metabolism. Celastrol is a bioactive compound that has been found to exhibit neuroprotective effects in cerebral ischemia, while whether it can protect against cerebral I/R injury by regulating glycolysis remains unclear. The goal of this study is to investigate the role of celastrol on cerebral I/R injury and its underlying mechanisms in transient middle cerebral artery occlusion (tMCAO) mice. Methods. To observe the protective effect of celastrol and select its optimal dosage for further study, neurological score, TTC staining, and HE staining were used to evaluate neurological function, cerebral infarct volume, and cortical cell damage, respectively. QRT-PCR and Western blot were used to detect the mRNA and protein expression of hypoxia inducible factor-1α (HIF-1α), pyruvate dehydrogenasekinase1 (PDK1), lactate dehydrogenase A (LDHA), glucose transporter1 (GLUT1), and hexokinase2 (HK2), respectively. The lactate production, ATP level, and glucose content were assessed by assay kits. Results. Our results indicated that celastrol dose-dependently improved neurological function and reduced cerebral infarct volume and cortical cell death of tMCAO mice, and its optimal dosage was 4.5 mg/kg. In addition, celastrol significantly blocked I/R-induced increase of LDHA, GLUT1, HK2, and lactate production as well as decrease of ATP level and glucose content. Moreover, celastrol inhibited the I/R-induced upregulation of HIF-1α and PDK1. Overexpression of HIF-1α by DMOG reversed the protective effect of celastrol on cerebral I/R injury and blocked celastrol-induced suppression of glycolysis. Conclusions. Taken together, these results suggested that celastrol protected against cerebral I/R injury through inhibiting glycolysis via the HIF-1α/PDK1 axis.

Improved Production of HIV-1 Subtype C Protease from Transgenic E. Coli

Background: Human Immunodeficiency Virus 1 (HIV-1) subtype C is responsible for the majority of infections of patients in Southern Africa. The HIV protease is a primary target for the development of highly efficient anti-retroviral pharmaceuticals because of its pivotal role in the maturation of the virus in the host cell. For target validation of novel HIV protease inhibitors, there is a need for the availability of an abundance of this protease. Objective: This study reports an optimized method to produce HIV-1 protease derived from HIV-1 subtype C. Methods: It involves the use of a transgenic E. coli strain that overexpresses the native form of the enzyme via inclusion bodies. A stringent method for the isolation, purification, and renaturation resulted in the production of highly pure active HIV-1 protease. In order to facilitate an increase in protease yields, an optimized growth strategy was developed. In this regard, a chemically defined medium with lower glucose content and devoid of essential amino acids of the TCA cycle was used as an alternative to the widely used nutrient-rich Luria Bertani (LB) medium. Results: Results indicated an increase in protease yield up to twice the amount, thereby making this medium an attractive alternative for increasing biomass and HIV protease production for future research. Conclusion: An optimized method for HIV-1 protease derived from HIV-1 subtype C production using chemically defined media was established. This was achieved using a known method to isolate and purify the enzyme with the use of a specialized feeding strategy.

A Study on Isolation and Identification of Exopolysaccharide (EPS) producing Bacteria from Soil

Polysaccharides are important potent molecules with their structural and compositional complexity which led to wide range of applications in various industries. The exopolysaccharides of microbial origin are released in response to extreme environmental conditions for the purpose of survival. The present study focuses on the isolation of exopolysaccharide producing bacteria from the soil sample and oil contaminated soil sample. Screening for the EPS production by the isolates is determined by the dry weight determination of precipitates of EPS and quantitative estimation of glucose content of EPS by PhenolSulphuric acid method. In the present study, out of 5 bacterial isolates isolated on screening, Lactobacillus sps and Pseudomonas sps. isolates produced the precipitates of EPS whose dry weight was determined to be 0.09g and 0.17g respectively. Further, glucose concentration of EPS was quantitatively determined. The glucose content of Lactobacillus sps. isolate was 0.1125mg/ml and Pseudomonas sps. isolate is 0.2875mg/ml. The EPS producing isolates were further grown in the presence of carbon sources like Glucose, Lactose, Maltose and Sucrose to determine the best utilizable carbon for their growth. The most utilizable carbon source for maximum growth of EPS producing isolates was determined to be sucrose with 2% concentration. All the 5 bacterial isolates were screened for their ability of antibiotic resistance. The EPS producing isolates, Lactobacillus sps, Pseudomonas sps were found to be resistant towards all the antimicrobial agents owing to the presence of EPS protective layer around their cell wall than non-EPS producing isolates. Keywords: Exopolysaccharide, Screening, Carbon sources, Antibiotic resistance.

Performa Dan Metabolit Darah Induk Kambing Bunting Yang Diberi Pakan Suplemen Selama Kebuntingan

Ketersediaan nutrisi pada induk baik melalui suplai dari makanan maupun hasil metabolisme induk mempunyai pengaruh sangat luas pada pertumbuhan fetus selama kebuntingan. Sangat diperlukan upaya perbaikan ketersediaan nutrisi melalui peningkatan sekresi endogen hormon metabolisme dan metabolit penting dan faktor-faktor pertumbuhan lainnya. Pengetahuan profil metabolik dapat berguna dalam memprediksi masalah metabolik. Penelitian ini dirancang mengikuti pola factorial 2 x 4 dengan 9 ulangan, sehingga jumlah kambing yang digunakan sebanyak 72 ekor induk kambing, yang terdiri dari kelompok kambing Peranakan Etawa dan kambing Kacang Pemberian pakan selama kebuntingan dibagi dalam 3 perlakuan induk bunting awal (umur kebuntingan 1 sampai 3 bulan), induk bunting akhir (umur kebuntingan 3 sampai 5 bulan), induk bunting tampa pemberian pakan suplemen dan Induk bunting dengan suplementasi selama kebuntingan. Pemberian pakan suplemen dapat meningkatkan pertambahan berat badan induk bunting. Waktu yang optimum pemberian pakan suplemen pada induk bunting memberikan pertambahan berat badan yang tinggi pada umur kebuntingan 1 sampai 3 bulan (awal). Kandungan glukosa darah dipengaruhi oleh jenis kambing dan umur kebuntingan. Kandungan glukosa darah tertinggi pada induk yang diberi pakan suplemen selama kebuntingan tetapi tidak berbeda pada kebuntingan awal dan akhir. Kandungan metabolit darah (urea dan kreatinine) tidak dipengaruhi oleh umur kebuntingan, dan kandungan metabolit darah relatif lebih tinggi pada ternak yang diberi pakan suplemen The availability of nutrients in the mother either through the supply of food or the results of the metabolism of the mother has a very broad influence on the growth of the fetus during pregnancy. It is necessary to improve the availability of nutrients by increasing the endogenous secretion of metabolic hormones and important metabolites and other growth factors. Knowledge of the metabolic profile can be useful in predicting metabolic problems. This study was designed to follow a 2 x 4 factorial pattern with 9 replications, so that the number of goats used were 72 mother goats, consisting of Etawa Peranakan goats and Kacang goats. 3 months), late pregnant women (gestational age 3 to 5 months), pregnant women without supplementation of feed and pregnant women with supplementation during pregnancy. Supplementary feeding can increase the weight gain of pregnant mothers. The optimum time of giving supplementary feed to pregnant mothers gives high weight gain at 1 to 3 months of gestation (early). Blood glucose content is influenced by the type of goat and gestational age. The blood glucose content was highest in broodstock fed supplements during pregnancy but did not differ in early and late pregnancy. The content of blood metabolites (urea and creatinine) was not affected by gestational age, and the content of blood metabolites was relatively higher in livestock fed supplementary diets.

The difference in temperature between day and night affects the strawberry soluble sugar content by influencing the photosynthesis, respiration and sucrose phosphatase synthase

Plenty of studies have demonstrated that DIF has an effect on the fruit growth. To study the effects of day and night temperature differences on the strawberry sugar quality, an experiment using climate chambers was conducted. Five different differences between the day and night temperatures (DIF) were set, which were 6 °C (28 °C/22 °C, day/night temperature), 8 °C (29 °C/21 °C), 10 °C (30 °C/20 °C), 12 °C (31 °C/19 °C), 14 °C (32 °C/18 °C). The results showed the following indices peaked with a DIF of 12 °C, including the photosynthesis rate, glucose content, fructose content, sucrose content, soluble sugar content and sugar metabolic enzyme activity. The respiration rate increased with the DIF during the day and decreased with the DIF at night. The root dry weight peaked at a DIF of 10 °C, the stolon dry weight peaked at a DIF of 8 °C and the leaf dry weight peaked at a DIF of 6 °C; however, the fruit dry weight reached maximum values at a DIF of 12 °C. The Grey correlation analysis showed that the most important factor in our experiment affecting the fructose content was the sucrose phosphate synthase; however, for the sucrose, glucose, and soluble sugars, the most important factor was the photosynthesis. We found that a DIF of 12 °C (31 °C/19 °C, day/night temperature) was the most suitable for strawberry growth, especially for the sugar content accumulation.

THE IMPACT OF PRODUCTION TREATMENTS OF FEED CONCENTRATE PRODUCED FROM WASTE OF CEREAL PRODUCTION ON ITS BIOLOGICAL VALUE AND EFFICIENCY IN THE COMPOSITION OF COMPOUND FEED FOR CARP

The following article presents a new raw component in compound feed for carp – feed concentrate produced from cereal production waste. The feed concentrate is based on several types of cereal fodder meal - wheat, pea, barley, as well as wheat bran and unshelled oat grain. The feed concentrate is balanced according to the needs of carp and can be used as feed for carp instead of wheat grain or as a part of compound feed for carp. Heat-moisture processing of compound feed before extrusion is one of the main stages that further ensure the stability of technological processes and the final quality of the feed concentrate. The amino acid composition was determined at various temperatures of the feed concentrate after heat-moisture treatment of + 40, 60, 70 and 80º С at a constant moisture content of the concentrate of +282° С. Amino acid score has been calculated for feed concentrates that have been exposed to various heat treatments. The amino score was calculated in relation to the carp's need for essential amino acids. It was found that an increase in the temperature of the concentrate during heat-moisture treatment leads to a decrease in the content of essential amino acids. For example, the total content of methionine and cysteine in the composition of the feed concentrate at a temperature of +75° C was 0.46%, with the minimum allowable total content of these amino acids in the composition of feed 0,5%. Heat-moisture treatment at a product temperature above +75° C leads to a decrease in the content of essential amino acids and the biological value of the feed concentrate.The process of extrusion of feed concentrate from waste of cereal production has been studied. The glucose content in the feed concentrate was studied at various extrusion modes. The glucose content indicates the degree of modification of the starch during the extrusion process, and the more glucose the product contains, the better it is absorbed by the carp. When extruded with an increase in temperature, the starch passes into a viscous-flowing (gelatinized) state, forming a so-called melt, the cooling of which also leads to the formation of a three-dimensional gel network. The feed concentrate granule becomes monolithic in structure; it becomes quite hard and can harm the intestines of carp. Therefore, it contains wheat bran in an amount of 1%, as a component that is able to weaken the feed concentrate granule. The degree of starch destruction in the composition of the extruded feed concentrate with the addition of wheat bran reached its maximum and the granule became porous, its hardness decreased. It was detected that when the temperature of the feed concentrate after extrusion rises above +100°C, the biological value of the feed concentrate decreases, and it becomes unbalanced in the content of such essential amino acids as lysine, threonine, methionine and cysteine. Therefore, the optimum product temperature after extrusion is +90-100˚C.The effectiveness of extruded feed concentrate was determined in the composition of granulated feed for two- and threeyear-old carp. The feed ratio of the compound feed containing the feed concentrate was 0.9 units, which is 64% lower than of the control compound feed, which includes a non-extruded grain group that is not balanced in terms of carp needs.

REPTOR/CREBRF encode key regulators of muscle energy metabolism

Metabolic flexibility of muscle tissue describes the capacity to use glucose or lipids as energy substrates and its disruption is associated with metabolic dysfunction. Cancer-induced cachexia is a metabolic syndrome linked with muscle wasting, changes in muscle energy metabolism and lower life expectancy in cancer patients. The molecular mechanisms driving metabolic changes in muscle, however, are poorly characterized. Here, using a Drosophila model of systemic metabolic dysfunction triggered by yorkie-induced gut tumors, we identify the transcription factor REPTOR as a key regulator of energy metabolism in muscle. We show that REPTOR is upregulated in muscles of adult flies with gut yorkie-tumors, where it is necessary to modulate glucose metabolism. REPTOR expression in muscles is induced by ImpL2, a tumor-derived insulin binding protein that reduces systemic insulin signaling, or by nutritional restriction. Further, in vitro and in vivo studies indicate that high activity of REPTOR is sufficient to increase glucose content, transcriptionally repress phosphofructokinase and increase mitochondrial respiration. Consistent with the fly studies, higher levels of CREBRF, the mammalian ortholog of REPTOR, reduce glycolysis in mouse myotubes while promoting an oxidative phenotype. Altogether, our results implicate REPTOR/CREBRF as key regulators of muscle metabolism and metabolic flexibility that share a conserved function as repressors of glycolysis and promoters of oxidative phosphorylation.

Influence of Floral Origin and Storage Conditions on Physicochemical Properties of Libyan Honeys

Aim: The effect of botanical origin and storage conditions on the quality of two Libyan monofloral honey samples (thyme and ziziphus honeys) were assessed during prolonged storage (12 months) at room temperature. Methodology: Physicochemical properties (moisture, viscosity, electrical conductivity, acidity pH, 5-(hydroxymethyl) furfural (HMF), diastase activity, sugars, and color) were monitored. Results: Generally, moisture, acidity, diastatic activity, and color values were significantly higher in thyme honey, whereas viscosity, electrical conductivity, pH, HMF, and sugars content were higher in ziziphus honeys. In comparison with the initial values, viscosity, acidity, and HMF values of all honey samples increased during storage. Storage period and containers did not affect the electrical conductivity and sucrose contents for the two honey types, which were below the stipulated limits. Moisture content, pH, diastatic activity, color (L*), fructose, and glucose content decreased during storage. Honey samples stored in opaque container showed significantly lower changes in all parameters during the storage period compared to those stored in transparent bottles. The results showed that both honey types stored for 12 months at room temperature could be considered safe for human consumption according to maintaining physicochemical parameters.