The use of cycloamylose to probe the “charge-relay” system

The effect of the combination of imidazolyl and carboxyl groups on the cleavage of m-t-butylphenyl acetate in the presence of α-cyclodextrin was examined to shed light on the role of the “charge-relay” system in serine esterases. 2-Benzimidazole-acetic acid, which has both the imidazolyl and carboxyl groups in the same molecule, accelerates the cleavage of m-t-butylphenyl acetate in the presence of α-cyclodextrin. On the other hand, neither benzimidazole (which has only an imidazolyl group) nor 2-naphthaleneacetic acid (which has only a carboxyl group) exhibited measurable acceleration. The cleavage of m-t-butylphenyl acetate by the α-cyclodextrin-2-benzimidazolecetic acid system takes place through inclusion complex formation between m-t-butylphenyl acetate and α-cyclodextrin, followed by catalysis associated with the combination of the carboxyl anion, the neutral imidazolyl group, and the alkoxide anion. The most probable explanation for the combination of the three groups in the catalysis involves nucleophilic attack by the imidazolyl group, assisted by the carboxyl and alkoxide anions. The mechanism of the combination of the imidazolyl, carboxyl, and hydroxyl groups is apparently different from those shown by the “charge-relay” system in enzymatic reactions.     

Reevaluation of use of retardation chromatography to demonstrate selective monosaccharide “binding” by erythrocyte membranes

Summary Retardation chromatography has been reported to show stereoselective binding of the preferred sugar-transport substrate,d-glucose, by human red cell ghosts or by certain protein extracts of such membranes. However, no detectable differential elution of glucose (as compared with the poorly transported analogue,l-sorbose) was observed with columns of diethylaminoethanol-cellulose impregnated with ghost proteins prepared by either of the recommended procedures (using Triton X-100, or NaI followed by extensive dialysis). Celite columns bearing intact ghosts did show marked initial relative delay in glucose emergence, but this persisted only partially through the elution peak, to be followed by a nearly equivalent and much more protracted retardation of the sorbose. Moreover, this differentiation required that the columns be handled sufficiently gently as to leave intact whole-cell membranes or fairly gross vesicles; freeze-thaw treatment or abrasive stirring abolished both the early glucose retardation and the subsequent sorbose retention. Although conflicting seriously with the simple selective-binding interpretation, these phenomena accord with the suggestion that the sugarcomplexing entities on the columns continue to operate as carriers mediating sugar access into membrane-enclosed compartments. Effects of experimental manipulation of elution rates and of applied sugar levels lend further support to this interpretation. The capacity of the vesicular spaces so vastly exceeds that of the binding itself that resolution of the latter cannot be achieved through this approach.Initial studies were carried out at Department of Pharmacology, University of Louisville School of Medicine, Louisville, Ky.     

Trichosporon asteroides Isolated from Cutaneous Lesions of a Suspected Case of “paracoccidioidomycosis ceti” in a Bottlenose Dolphin (Tursiops truncatus)

Mycopathologia - “Paracoccidioidomycosis ceti” is a rare zoonotic fungal infection affecting dolphins and is endemic worldwide. The causative agents are Paracoccidioides species;...     

“Wisdom of the Elders” or “Loss of Experience” as a Mechanism to Explain the Decline in Traditional Ecological Knowledge: A Case Study on Awaji Island,Japan

Human Ecology - Previous studies have reported that older people are more knowledgeable about nature than the younger generation. The relationship between people’s age and level of knowledge...     

Successful use of a novel lux® i-Amylose-1 chiral column for enantioseparation of “legal highs” by HPLC

Bath salts, fumigations, cleaners and air fresheners, behind these terms substances are hidden, which count as “Legal Highs”. These fancy names are used to pretend Legal Highs as harmless compounds, to circumvent legal regulations for marketing as well as to increase the sales. Besides classic illicit drugs of synthetic origin such as amphetamines, cocaine and MDMA, the trade of these compounds, also known as new psychoactive substances (NPS), is not uncommon today. In many countries, NPS are still not subject to drug control. Among them, there are stimulants such as new amphetamine derivatives or cathinones, which possess a chiral centre. Little is known about the fact that the two possible enantiomers may differ in their pharmacological effect. The aim of this study was to test a novel HPLC column for the enantioseparation of a set of 112 NPS coming from different chemical groups and collected by internet purchases during the years 2010–2018. The CSP, namely Lux® 5 μm i-Amylose-1, LC Column 250 x 4.6 mm, was run in normal phase mode under isocratic conditions, UV detection was performed at 245 nm and 230 nm, injection volume was 10 μl and flow rate was 1 ml/min. With a mobile phase consisting of n-hexane/isopropanol/diethylamine (90:10:0.1), herein, 79 NPS were resolved into their enantiomers successfully, for 37 of them baseline resolution was achieved. After increase of lipophily of the mobile phase to 99:1:0.1, another 27 compounds were baseline separated. It was found that all separated NPS are traded as racemic compounds.     

Correction to: Creating a “family tree” on fertilizer inventory use in life cycle assessment of oil palm: visualization of earlier studies and its implications

The International Journal of Life Cycle Assessment - The original version of this article unfortunately contained a mistake.     

A Case of “Late-Onset” Idiopathic Infantile Hypercalcemia Secondary to Mutations in the CYP24A1 Gene

ObjectiveMutations in the 24-hydroxylase gene, CYP24A1, have recently been reported to cause idiopathic infantile hypercalcemia (IIH), a rare disease presenting in the first year of life that is characterized by increased sensitivity to vitamin D, leading to severe symptomatic hypercalcemia.MethodsWe present a case report and review the relevant literature.ResultsA 24-year-old Caucasian man presented with repetitive signs of nephrolithiasis since the age of 18 years, hypercalciuria (17.1 mmol/24 h), slightly elevated serum calcium concentration (2.64 mmol/L), and inappropriately high levels of 1,25-dihydroxyvitamin D (101 pg/mL) in combination with suppressed levels of circulating parathormone (7.9 pg/mL). Exogenous vitamin D intoxication as well as granulomatous disease or malignancy were excluded. Genetic analysis revealed a loss-of-function mutation in CYP24A1. Of note, our patient denied any prior clinical signs of impaired calcium homeostasis during childhood.ConclusionHere, we describe the exceptional case of a patient with hypercalciuria and recurrent nephrolithiasis secondary to mutations in CYP24A1, without any signs of IIH in childhood, indicating that the phenotypic spectrum includes mild “late-onset” disease that becomes symptomatic in adolescence. Therefore, reduced CYP24A1 activity should be considered as a possible reason for recurrent nephrolithiasis in adults. (Endocr Pract. 2014;20: e91-e95)