Enhancing Staphyloxanthin Synthesis in Staphylococcus aureus Using Innovative Agar Media Formulations.

Background Staphyloxanthin, a carotenoid pigment found in Staphylococcus aureus, serves not only to impart color but also functions as a crucial antioxidant contributing to virulence. Traditionally, milk agar has been employed to enhance staphyloxanthin production, however, no alternative media have been explored. Objectives This study aims to enhance staphyloxanthin production in Staphylococcus aureus using beetroot and carrot formulations. Methods To assess the efficacy of the media, we utilized filter paper, slide spot tests, and microscopic visualization as preliminary identification techniques. Ultraviolet-visible (UV-Vis) spectroscopy and paper chromatography were employed for characterization. Pigment quantification was conducted using microtiter plate assays, and genotypical detection was performed using Reverse Transcriptase-quantitative Polymerase Chain Reaction (RT-qPCR). Results Beetroot agar exhibited the highest pigment intensity, followed by beetroot with carrot agar, milk agar, carrot agar, and nutrient agar with the lowest intensity. These novel media formulations increased staphyloxanthin synthesis yield, resulting in spectrum shifts ranging from 450 nm (yellow) of milk agar to 470 nm (carrot agar) /480 nm (orange) of beetroot agar. Conclusion This study demonstrates that beetroot and carrot agar can effectively enhance staphyloxanthin production in Staphylococcus aureus. Furthermore, we propose the potential for large-scale cultivation of these pigments in future studies for various industrial applications, such as integration into paints, fabrics, and sunscreen lotions, due to their antioxidant properties.

Zinc toxicity to aminergic neurotransmitters in rat brain.

The present study was aimed to evaluate zinc toxicity to aminergic system in different areas of the brain of male albino rat, Rattus norvegicus. Zinc toxicity, evaluated as per Probit method was found to be 500 mg/kg body weight. For acute-dose studies, rats were given a single lethal dose of zinc chloride for one day only and for chronic-dose studies, the rats were administered with sub-lethal doses (1/10(th) of lethal dose) of zinc chloride every day for 90 days continuously. Various constituents of the aminergic system viz. dopamine, norepinephrine, and epinephrine and the catabolizing enzyme, monoamine oxidase (MAO) were determined in different regions of rat brain such as olfactory lobe, hippocampus, cerebellum, and pons-medulla on selected time intervals/days under acute and chronic treatment with zinc. The results revealed that while the levels of all aminergic neurotransmitters were elevated differentially in the above mentioned areas of brain, MAO activity registered nonsignificant inhibition in all brain regions under zinc toxicity. All these changes in the aminergic system were subsequently manifested in the behavior of rat exhibiting the symptoms of mild tremors, reduced locomotor activity and emotions, restlessness followed by lacrymation, salivation, etc. From these observations, it was obvious that zinc treatment caused severe perturbations in the functions of the nervous system. Restoration of the aminergic system along with behavior to the near normal levels under chronic treatment indicates the onset of detoxification mechanisms or development of tolerance to zinc toxicity in the animal which was not probably so efficient under acute treatment.

Cholinergic system under aluminium toxicity in rat brain.

The present investigation envisages the toxic effects of aluminium on the cholinergic system of male albino rat brain. Aluminium toxicity (LD(50)/24 h) evaluated as per Probit method was found to be 700 mg/kg body weight. One-fifth of lethal dose was taken as the sublethal dose. For acute dose studies, rats were given a single lethal dose of aluminium acetate orally for one day only and for chronic dose studies, the rats were administered with sublethal dose of aluminium acetate once in a day for 25 days continuously. The two constituents of the cholinergic system viz. acetylcholine and acetylcholinesterase were determined in selected regions of rat brain such as cerebral cortex, hippocampus, hypothalamus, cerebellum, and pons-medulla at selected time intervals/days under acute and chronic treatment with aluminium. The results revealed that while acetylcholinesterase activity was inhibited, acetylcholine level was elevated differentially in all the above mentioned areas of brain under aluminium toxicity, exhibiting area-specific response. All these changes in the cholinergic system were subsequently manifested in the behavior of rat exhibiting the symptoms such as adipsia, aphagia, hypokinesia, fatigue, seizures, etc. Restoration of the cholinergic system and overt behavior of rat to the near normal levels under chronic treatment indicated the onset of either detoxification mechanisms or development of tolerance to aluminium toxicity in the animal which was not probably so efficient under acute treatment.

A new model for vitamin K-dependent carboxylation: the catalytic base that deprotonates vitamin K hydroquinone is not Cys but an activated amine.

Vitamin K-dependent (VKD) proteins require carboxylation for diverse functions that include hemostasis, apoptosis, and Ca(2+) homeostasis, yet the mechanism of carboxylation is not well understood. Combined biochemical and chemical studies have led to a long-standing model in which a carboxylase Cys catalytic base deprotonates vitamin K hydroquinone (KH(2)), leading to KH(2) oxygenation and Glu carboxylation. We previously identified human carboxylase Cys-99 and Cys-450 as catalytic base candidates: Both were modified by N-ethylmaleimide (NEM) and Ser-substituted mutants retained partial activity, suggesting that the catalytic base is activated for increased basicity. Mutants with Cys-99 or Cys-450 substituted by Ala, which cannot ionize to function as a catalytic base, were therefore analyzed. Both single and double mutants had activity, indicating that Cys-99 and Cys-450 do not deprotonate KH(2). [(14)C]NEM modification of C99A/C450A revealed one additional reactive group; however, Ser-substituted mutants of each of the eight remaining Cys retained substantial activity. To unequivocally test, then, whether any Cys or Cys combination acts as the catalytic base, a mutant with all 10 Cys substituted by Ala was generated. This mutant showed 7% wild-type activity that depended on factor IX coexpression, indicating a VKD protein effect on carboxylase maturation. NEM and diethyl pyrocarbonate inhibition suggested that the catalytic base is an activated His. These results change the paradigm for VKD protein carboxylation. The identity of the catalytic base is critical to understanding carboxylase mechanism and this work will therefore impact both reinterpretation of previous studies and future ones that define how this important enzyme functions.

Blood pressure and adiposity: A comparative study of socioeconomically diverse groups of Andhra Pradesh, India.

The effect of adiposity on blood pressures, systolic (SBP), and diastolic (DBP), was examined in a sample of 1119 individuals (456 males, 663 females), 18-75 years, from socioeconomically diverse populations from Southern Andhra Pradesh, India. The populations were graded into four socioeconomic groups, group I-seminomadic Yerukalas, group II-hard working scheduled caste Mala and the Muslims, group III-land owning agricultural castes Reddy and Balija, and group IV-sedentary urban dwelling castes such as Brahmins, Vyshyas, and Marwadis. There was a trend of increase in mean blood pressures and the frequency of hypertensives (SBP ≥160 and/or DBP ≥95) with increasing age in all groups, and the increase was more distinct from group I to group IV. Mean values of body mass index (BMI: weight/height2 ) and body fat (SF4: sum of biceps, triceps, subscapular, and suprailiac skinfolds) also showed an increasing trend from group I to group IV. A somewhat opposite trend was evident in two indices of fat distribution, centripetal fat ratio (CFR: ratio of subscapular to the sum of subscapular and triceps skin fold thicknesses) and the relative fat pattern index (RFPI: ratio of subscapular skinfold thickness to the sum of subscapular and suprailiac skinfold thicknesses). Step-wise regression analysis indicated that while one or the other adiposity measures along with one of the age terms significantly contributed to SBP variation among males in the affluent groups III and IV, neither any adiposity measure nor age explain the variation in group I, and only body fat, not age, in group II. A qualitatively similar pattern was observed in females, except that BMI explained a significant amount of variation in SBP in group I, and only age and not any of the adiposity measures, in group IV. Besides age, BMI and fat pattern indices accounted for a significant amount of variation in DBP, while RFPI explained a significant amount of variation in group IV. The amount of variation in SBP explained by the age and adiposity measures increased from the traditional to urbanized groups in males (2.4% to 24.8%) and females (11.4% to 43.6%). A similar trend was observed in case of DBP in both males (0.2% to 15.4%) and females (7.6% to 21.8%). Analysis of covariance of the pooled sample suggested that each of five categorical variables-physical activity, smoking, income, food habit, and group membership-independently explained a significant amount of residual variation in SBP of males, while only food habit and social status did so in females. DBP variation, however, was significantly accounted for by only three of the five (excluding food habit and smoking) categorical variables in males and by none in females. The effect of categorical variables on the residual variation in SBP becomes increasingly significant from the traditional to the urbanized groups in males, while this trend is not consistent in females. Am. J. Hum. Biol. 10:5-21, 1998. © 1998 Wiley-Liss, Inc.