Oxygen supply to bacterial suspensions of high cell densities by hydrogen peroxide

The supply of heterotrophically growing suspensions of Alcaligenes eutrophus PHB^?4 with oxygen formed by the continuous addition of H₂O₂ in the presence of bovine liver catalase was found to be restricted to well-defined conditions. The catalase-H₂O₂ system proved to be suitable during the growth at low cell densities equivalent to 2 g dry weight/liter. When under these conditions the oxygen concentration was held constant at 1.8 mg O₂/liter, the cells grew for 6–8 hr at a rate almost identical to that observed with conventional aeration. However, aeration with H₂O₂ for longer durations (10–20 hr) and at higher cell densities (5?20 g dry weight/liter) led invariably to cell damage and retardation of growth. The impairment of growth observed during the oxygen supply by the catalase?H₂O₂ system was traced back to the formation of gradually increasing steady-state concentrations of H₂O₂ in the medium. Possible sites of cell damage by H₂O₂ such as membrane function, excretion and function of siderophores, and synthesis of cell polymers have been studied, and the cytotoxic mechanism of low concentrations of H₂O₂ was discussed.     

FAMILIAL VALVULAR PULMONIC STENOSIS INVOLVING THREE SIBLINGS

This report describes the cases of three mentally and physically well-developed siblings, 12, 10, and 8 years of age, with varying degrees of isolated valvular pulmonic stenosis not related to age. The severest lesion occurred in the middle patient and was associated with a right-to-left shunt through a patent foramen ovale. The three children had no other siblings, and there was no history of congenital heart disease among close relatives. These cases support the conclusion that genetic factors play a significant role in the development of certain congenital cardiac disorders.     

Hemin feedback inhibition at reticulocyte δ-aminolevulinic acid synthetase and δ-aminolevulinic acid dehydratase

Addition of hemin (5–200 μM) to a rabbit reticulocyte iron-free incubation medium, resulted in a progressive inhibition of heme synthesis as measured by incorporation of (¹⁴C)-glycine. In contrast when (¹⁴C) δ-aminolevulinic acid incorporation into heme was studied, significant inhibition below that of the (¹⁴C)-glycine control only occurred with hemin concentrations greater than 100 μM. Hemin progressively inhibited cellular and mitochondrialδ-aminolevulinic acid synthetase activity, as well as cellular δ-aminolevulinic acid dehydratase activity. The results indicated that elevated levels of hemin initially control heme synthesis by feedback inhibition at the rate-limiting enzyme of heme synthesis, δ-aminolevulinic acid synthetase. Hemin inhibition of δ-aminolevulinic acid dehydratase is only significant for the entrire heme synthetic pathway when greater than one-third of this enzyme's activity is inhibited.     

Reactions of 3-(1-arylhydrazono-L-threo-2,3,4-trihydroxybutyl)-1-methyl-2-Quinoxalinones

The 1-methyl derivatives (3 and 4) of 3-(1-phenyl- (1) and 3-(1-p-bromophenylhydrazono-L-threo-2,3,4-trihydroxybutyl)-2-quinoxalinone (2) were prepared by methylation. Periodate oxidation of 3 gave 1-methyl-3-[1-(phenylhydrazono)glyoxal-1-yl]-2-quinoxalinone (5), which, on reduction with sodium borohydride, gave the corresponding 3-[2-hydroxy-1-(phenylhydrazono)ethyl] derivative (8). Reaction of 5 with hydroxylamine or benzoylhydrazine gave the corresponding 2-oxime (6) and 2-(benzoylhydrazone) (7), respectively. Acetic anhydride causes one molecule of 3 or 4 to undergo elimination of two molecules of water, with simultaneous acetylation and ring closure to afford pyrazoles 9 and 10, respectively. Pyrolysis of the triacetate of 3 led to the elimination of acetic acid from the sugar and the hydrazone residue, to give the 3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl] derivatives (9). Acetic acid was found to effect the same rearrangement, but without acetylation, of 1, 2, and 3 to give the 3-[5-(hydroxymethyl)] derivatives 11, 12, and 13, respectively. The structure of these pyrazoles was confirmed by a series of reactions, including methylation and acetylation. The n.m.r. and i.r. spectra of the compounds were investigated.     

Phenolic synthesis in Perilla cell suspension cultures

Suspension cultures of Perilla ocymoides accumulate caffeic acid, both in free and ester forms, as the only phenylpropanoid end metabolite. Increased levels of growth substances influenced the levels of PAL activity and phenolic accumulation so that cytokinin stimulated, while auxin repressed both parameters. The regulatory role of caffeyl compounds is discussed in relation to their accumulation during the early exponential phase of culture growth.     

Anthropological studies among Libyans. Erythrocyte genetic factors,serum haptoglobin phenotypes and anthropometry

Anthropological studies were done on 1276 Libyans from the Mediterranean cities of Tripoli and Benghazi, and from Sabha southward in The Sahara. The incidences of hemoglobin (Hb)-S and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were low in the coastal areas and significantly high in Sabha. Hb-C occurred sporadically in Tripoli and Sabha, and was absent from Benghazi in the east. One case of Hb-J Benghazi was noted. There were no significant differences in the ABO blood group and Rh₀ (D) type distributions in the three localities. G-6-PD gene Gd^A frequency was significantly high in Sabha. The lowest value of 6-phosphogluconate dehydrogenase (6-PGD) gene PGD^A frequency and highest value of the gene PGD^C were in Sabha. Adenylate kinase (AK) gene AK² was only detectable in Tripoli. Acid phosphatase (AP) gene P^a frequency in Sabha was more than twice that in Tripoli and Benghazi, while P^c was distinctly lower in Sabha than in the northern cities. Haptoglobin gene Hp¹ frequency was almost identical in all areas. Anthropometric measurements revealed overall homogeneity of the three samples, closer similarity in the coastal region to adjacent North African populations, and Negroid influence in the Saharan Libyans. Anthropometry substantiated findings from blood markers.     

Evaluation of amino acid profile in serum of patients with Covid-19 for providing a new treatment strategy

BackgroundAmino acids have an important role in metabolism and may affect COVID-19-related outcomes. In our study, the amino acid serum level of hospitalized COVID19 patients was evaluated to determine a new treatment strategy.MethodsThe amino acid profile covering 43 amino acids in 68 subjects, comprising 30 (14 men and 16 women) controls and 38 (16 men and 22 women) COVID-19 patients, were examined. The amino acid profiles of the participants were screened by LC-MS/MS.ResultsCompared with the control group, serum levels of 27 amino acids increased in the patient group. Alpha-aminopimelic acid, sarcosine, and hydroxyproline amino acids were considerably higher in the control group than in the patient group (p<0.0001). There was no notable difference among control group and the case group for 13 amino acids (p≥0.05). A significant positive correlation was seen among the control and the patient groups in the mean amino acid values (r=0.937; p<0.0001).ConclusionsThese results postulated a clear picture on the serum levels of amino acid in the COVID-19 patients. Serum amino acids measured in hospitalized COVID-19 patients can explain the patient''s metabolic status during the disease.     

Identification of Protor as a novel Rictor-binding component of mTOR complex-2

The mTOR (mammalian target of rapamycin) protein kinase is an important regulator of cell growth. Two complexes of mTOR have been identified: complex 1, consisting of mTOR-Raptor (regulatory associated protein of mTOR)-mLST8 (termed mTORC1), and complex 2, comprising mTOR-Rictor (rapamycininsensitive companion of mTOR)-mLST8-Sin1 (termed mTORC2). mTORC1 phosphorylates the p70 ribosomal S6K (S6 kinase) at its hydrophobic motif (Thr389), whereas mTORC2 phosphorylates PKB (protein kinase B) at its hydrophobic motif (Ser473). In the present study, we report that widely expressed isoforms of unstudied proteins termed Protor-1 (protein observed with Rictor-1) and Protor-2 interact with Rictor and are components of mTORC2. We demonstrate that immunoprecipitation of Protor-1 or Protor-2 results in the co-immunoprecipitation of other mTORC2 subunits, but not Raptor, a specific component of mTORC1. We show that detergents such as Triton X-100 or n-octylglucoside dissociate mTOR and mLST8 from a complex of Protor-1, Sin1 and Rictor. We also provide evidence that Rictor regulates the expression of Protor-1, and that Protor-1 is not required for the assembly of other mTORC2 subunits into a complex. Protor-1 is a novel Rictor-binding subunit of mTORC2, but further work is required to establish its role.