ON A NEW SPECIES OF BOULTONIA

Early in 1927, Prof. J. S. Lee erected the genus Boultonia, the genotype ofwhich is Boultonia willsi. In the same publication, he described another speciesBoultonia rawi from the Penchi Series of the Moscovian age. This latter specieshas been afterwards transferred by various authors to Wedekindellina. Later in1934, Prof. S. Chen described a new species of Boultonia, B. cylindrica, from the     

Morphological and structural adaptation of nodules of cowpea to functioning under sub- and supra-ambient oxygen pressure

Nodules of cowpea (Vigna unguiculata (L.) Walp. cv. Vita 3:Bradyrhizobium CB 756) from 28-d-old plants cultured for 23 d with their root systems maintained in O₂ levels from 1 to 80% (v/v, in N₂) in the external gas phase showed a range of structural changes which have been interpreted in relation to an over- or under-supply of O₂. A response to the partial pressure of O₂ in the gas phase (pO₂) was noted with respect to nodule size, lenticel development, the relative distributions of cortical and infected central tissue, the differentiation of cortex, especially the inner cortex, the frequency and size of infected and uninfected interstitial cells, the volume of extracellular spaces both in cortex and infected tissue, and in the frequency of bacteroids. As a consequence of these changes the surface area of inner cortex relative to the nitrogenase-containing units of fixing tissue (infected cells or bacteroids) was increased by as much as 20-fold. Effectiveness of bacteroid functioning increased from 0.10 ± 0.02 · 10^-9 μmol acetylene reduced per bacteroid in air-grown nodules to 0.9 ± 0.16 · 10^-9 (same units) per bacteroid in those cultured in 1% O₂. This work was supported by a grant from the Australian Research Council (to C.A.A.) and an Australian International Development Assistance Bureau postgraduate fellowship (to F.D.D.). The authors wish to thank Dr. W.F.C. Blumer for his considerable help with morphometric analysis, Dr. J. Kuo for guidance in the use of histological techniques, and to Dr. J.S. Pate for the suggestion that lenticel development might be quantified by surface staining of nodules.     

Defective autophagy in multidrug resistant cells may lead to growth inhibition by BH3‐mimetic gossypol

The clinical efficacy of many chemotherapeutic agents has been reduced due to the development of drug resistance. In this article, we aimed to validate gossypol, a natural BH3 mimetic found in cottonseeds, as a potential therapeutic to overcome multidrug resistance (MDR). Gossypol was found to retain its efficacy in v‐Ha‐ras‐transformed NIH 3T3 cells that overexpressed P‐glycoprotein (Ras‐NIH 3T3/Mdr), which was similar to the efficacy observed in their parental counterparts (Ras‐NIH 3T3). A rhodamine assay revealed that the alteration of MDR activity did not contribute to the cytotoxic effect of gossypol. Gossypol caused a G₂/M arrest by the induction of p21^Cip1 and the down‐regulation of p27^Kip1 expression in Ras‐NIH 3T3 cells, whereas no significant G₂/M arrest was exhibited in Ras‐NIH 3T3/Mdr cells. Surprisingly, a 48‐h treatment with gossypol induced apoptotic cell death in Ras‐NIH 3T3 cells; however, gossypol induced both apoptosis and necrosis in Ras‐NIH 3T3/Mdr cells, as determined with flow cytometry analysis. More notably, gossypol preferentially induced autophagy in Ras‐NIH 3T3 cells but not in Ras‐NIH 3T3/Mdr cells. Coimmunoprecipitation and flow cytometric analysis revealed that gossypol‐induced autophagy is independent of the dissociation of Beclin 1 from Bcl‐2 in Ras‐NIH 3T3 cells. Taken together, these results suggest that the antiproliferative activity of gossypol appears to be due to cell‐cycle arrest at the G₂/M phase, with the induction of apoptosis in Ras‐NIH 3T3 cells. In addition, defective autophagy might contribute to apoptotic and necrotic cell death in response to gossypol in Ras‐NIH 3T3/Mdr cells. J. Cell. Physiol. 228: 1496–1505, 2013. © 2012 Wiley Periodicals, Inc.     

The fine structure of neuroglia in the central nervous system of nereid polychaetes

Summary The principal supportive elements of the nereid central nervous system are non-neuronal cells that are referred to as supportive glia. Supportive glial cells form a conspicuous cortex in the nerve cord. The inner region of this cortex consists of closely packed processes and cell bodies of fibrous supportive glial cells that are arranged in concentric layers around the perimeter of the neuropile. The fibrous appearance of the glial cells results from dense bundles of cytoplasmic filaments. Many fibrous glial processes penetrate the neuropile and ramify among the neuronal elements. Larger, irregularly shaped cells are the chief supportive glial elements of the peripheral region of the cortex where they line the stromal sheath (neural lamella) and invest the neuronal perikarya with extensive concentric systems of lamellate processes. These glial cells usually possess a relatively undifferentiated cytoplasm with scattered glycogen granules, but occasionally have a well developed Golgi apparatus, endoplasmic reticulum and densely packed particulate glycogen. The supportive glia exhibits numerous desmosomes as well as 5-layered (tight) and 7-layered (gap) junctions. Interspersed among the supportive glial cells are non-neuronal cells referred to as granulocytes. These cells have abundant large, granular inclusions, electron lucent vesicles, plasmalemmal infoldings and microtubules. The granulocytes may be derived from undifferentiated glial cells or may represent coelomocytes that have invaded the nervous tissue.Supported by USPHS Grants No. NIH 5P01 NS-07512, NIH 2T01 GM-00102, and NB-00840.The author acknowledges the excellent technical assistance of Sarah Wurzelmann and Stanley Brown, and thanks Dr. Berta Scharrer for many stimulating discussions.     

Selective Increases in Phosphoinositide Signaling Activity and G Protein Levels in Postmortem Brain from Subjects with Schizophrenia or Alcohol Dependence

Abstract: Comparisons of the activity of the G protein-mediated phosphoinositide signal transduction system and of G protein levels were made in two regions of frontal cortex from eight schizophrenic, alcohol-dependent, and control subjects. G protein-mediated phosphoinositide hydrolysis was measured by stimulating cortical membranes incubated with [³H]phosphatidylinositol with 0.3–10 µM guanosine 5′-O-(3-thio)triphosphate (GTPγS). In frontal cortex areas 8/9, GTPγS-induced phosphoinositide hydrolysis was 50% greater in schizophrenic than control or alcohol-dependent subjects, whereas there were no differences among these groups of subjects in the response to GTPγS in frontal cortex area 10. Agonists for dopaminergic, cholinergic, purinergic, serotonergic, histaminergic, and glutamatergic receptors coupled to the phosphoinositide signaling system increased [³H]phosphatidylinositol hydrolysis in a GTPγS-dependent manner. Responses to most agonists were similar in all three subject groups in both cortical regions, with the largest difference being a 40% greater response to dopaminergic receptor stimulation in frontal cortex 8/9 from schizophrenic subjects. Measurements of the levels of phospholipase C-β, and of α-subunits of G_q, G_o, G_i1, G_i2, and G_s, made by immunoblot analyses revealed no differences among the groups of subjects except for increased Gα_o in schizophrenic subjects and increased Gα_o and Gα_i1 in alcohol-dependent subjects. These results demonstrate that schizophrenia is associated with increased activity of the phosphoinositide signal transduction system and increased levels of Gα_o, whereas the phosphoinositide system was unaltered in alcohol dependence, but Gα_o and Gα_i1 were increased.     

Selective-Differential Medium for Isolation and Differentiation of Pectinatus from Other Brewery Microorganisms

An agar medium, LL-agar (lactate-lead acetate) was designed to selectively differentiate members of the genus Pectinatus (S. Y. Lee, M. S. Mabee, and N. O. Jangaard, Int. J. Syst. Bacteriol. 28:582-594, 1978; S. Y. Lee, M. S. Mabee, N. O. Jangaard, and E. K. Horiuchi, J. Inst. Brew. 86:28-30, 1980) from other brewery microorganisms. Selectivity was achieved by the use of sodium lactate as the sole source of carbon and phenylethyl alcohol as an inhibitor for aerobic gram-negative bacteria and yeast. Differentiation was established by the introduction of lead acetate into the medium, which reacted with the H₂S liberated by Pectinatus and resulted in a blackening of the Pectinatus colonies while the other brewery organisms, when present, remained white. In combination with the Lee tube (J. E. Ogg, S. Y. Lee, and B. J. Ogg, Can. J. Microbiol. 25:987-990, 1979) and this medium, isolation of Pectinatus organisms from beer samples was accomplished with convenience and simplicity.     

A delayed-recruitment model of population dynamics,with an application to baleen whale populations

Summary This paper studies the delay equation x _k+1=x _k+F(x _k–), which has been employed as a model of baleen whale population dynamics. The two main questions discussed are (a) stability of equilibria, and (b) optimal exploitation policies.This paper was written while the author was visiting CSIRO Division of Fisheries & Oceanography, Cronulla, NSW, Australia. Support from CSIRO, from the National Research Council of Canada (Grant A-3990), and from the Killam Foundation is gratefully acknowledged. The author thanks Dr. K. R. Allen, Prof. V. T. Buchwald, Dr. B. S. Goh, and Dr. G. P. Kirkwood for their assistance.     

Applied Spatial Data Analysis with R. by BIVAND, R. S., PEBESMA, E. J., and GOMEZ-RUBIO, V.

Applied Spatial Data Analysis with R (R. S. Bivand, E. J. Pebesma, and V. Gomez‐Rubio) Jay M. Ver Hoef Bayesian Disease Mapping: Hierarchical Modeling in Spatial Epidemiology (A. B. Lawson) J. Law Disease Surveillance: A Public Health Informatics Approach (J. S. Lombardo and D. L. Buckeridge, editors) Iris Pigeot Survival Analysis for Epidemiologic and Medical Research (S. Selvin) M. G. Valsecchi Survival and Event History Analysis: A Process Point of View (O. O. Aalen, O. Borgan, and H. K. Gjessing) Patricia Grambsch Nonlinear Dimensionality Reduction (J. A. Lee and M. Verleysen) Haonan Wang Model Selection and Model Averaging (G. Claeskens and N. L. Hjort) Thomas M. Loughin Meta‐Analysis of Binary Data Using Profile Likelihood (D. Böhning, R. Kuhnert, and S. Rattanasiri) Eloise Kaizar Wavelet Methods in Statistics with R (G. P. Nason) Jeffrey S. Morris Adaptive Design Theory and Implementation Using SAS and R (M. Chang) Feifang Hu Ecological Models and Data in R (B. M. Bolker) Rachel M. Fewster Applied Multiway Data Analysis (P. M. Kroonenberg) Renato Coppi Brief Reports by the Editor Sampling of Populations: Methods and Applications, 4th edition (P. S. Levy and S. Lemeshow) Applied Survival Analysis: Regression Modeling of Time‐to‐Event Data, 2nd edition (D. W. Hosmer, S. Lemeshow, and S. May) SAS for Data Analysis: Intermediate Statistical Methods (M. G. Marasinghe and W. J. Kennedy) Advances in Mathematical and Statistical Modeling (B. C. Arnold, N. Balakrishnan, J. M. Sarabia, and R. Mínguez, editors) An Introduction to Generalized Linear Models, 3rd edition (A. J. Dobson and A. G. Barnett) Design and Analysis of Bioavailability and Bioequivalence Studies, 3rd edition (S.‐C. Chow and J.‐P. Liu)     

The mechanism of acute fasting‐induced antidepressant‐like effects in mice

Acute fasting induced antidepressant‐like effects. However, the exact brain region and mechanism of these actions are still largely unknown. Therefore, in this study the antidepressant‐like effects of acute fasting on c‐Fos expression and BDNF levels were investigated. Consistent with our previous findings, immobility time was remarkably shortened by 9 hrs fasting in the forced swimming test. Furthermore, these antidepressant‐like effects of 9 fasting were inhibited by a 5‐HT_2A/2C receptor agonist (±)‐1‐(2, 5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane hydrochloride (DOI), and the effect of DOI was blocked by pretreatment with a selective 5‐HT_2A receptor antagonist ketanserin. Immunohistochemical study has shown that c‐Fos level was significantly increased by 9 hrs fasting in prefrontal cortex but not hippocampus and habenular. Fasting‐induced c‐Fos expression was further enhanced by DOI in prefrontal cortex, and these enhancements were inhibited by ketanserin. The increased BDNF levels by fasting were markedly inhibited by DOI in frontal cortex and hippocampus, and these effects of DOI on BDNF levels were also blocked by ketanserin. These findings suggest that the antidepressant‐like effects of acute fasting may be exerted via 5‐HT_2A receptor and particularly sensitive to neural activity in the prefrontal cortex. Furthermore, these antidepressant‐like effects are also mediated by CREB and BDNF pathway in hippocampus and frontal cortex. Therefore, fasting may be potentially helpful against depression.     

Electron-microscopic cytochemical localization of diamine and polyamine oxidases in pea and maize tissues

An electron-microscopic cytochemical method was used to localize diamine oxidase (DAO) in pea and polyamine oxidase (PAO) in maize (Zea mays L.). The method, based on the precipitation of amine-oxidase-generated H₂O₂ by CeCl₃, was shown to be specific for DAO and PAO and permitted their localization in plant tissues with a high degree of resolution. Both enzymes are localized exclusively in the cell wall. Both DAO- and PAO-activity staining is most intense in the middle lamellar region of the wall and in cells exhibiting highly lignified walls. The oxidases could provide H₂O₂ for peroxidase-mediated cross-linking reactions in the cell wall and may, in this capacity, play a role in the regulation of plant growth.Abbreviations AG 1-aminoguanidine - AT 3-amino-1,2,4-triazole - -HEH -hydroxyethylhydrazine - DAO(s) diamine oxidase(s) - PAO(s) polyamine oxidase(s) - Put putrescine - Spd spermidine - Spm spermine The authors wish to thank Nancy Piatczyc for the technical assistance with electron-microscopy studies. We are grateful to Dr. Stanley J. Roux, University of Texas at Austin, for providing us with samples of maize cell-wall exudates. This work was supported by grants to R.D.S from the National Aeronautics and Space Administration (NAGW-1049 and NAGW-1382).     

Reduction of Salmonella on alfalfa seeds using peroxyacetic acid and a commercial seed washer is as effective as treatment with 20 000 ppm of Ca(OCl)2

Aims: The efficacy of a commercial seed washer and 1 and 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for reducing Salmonella on alfalfa seeds was investigated. Methods and Results: Alfalfa seeds were inoculated with Salmonella Stanley to achieve c. 5 log CFU g^?1. Seeds were then treated with 1 or 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for 15 min in a commercial seed washer that uses air to enhance contact of the sanitizer with the seed. Experiments were also conducted using industry and laboratory methods. An c. 1‐log reduction in number of Salm. Stanley was demonstrated regardless of the chemical treatment or method of treatment. Although this 1‐log reduction was significant (P < 0·05), differences among the treatments were not significant. Treating the seed with 1 and 3% peroxyacetic acid resulted in similar Salm. Stanley reductions of 1·77 and 1·34 log, respectively, not being statistically significant (P > 0·05). Conclusions: These results suggest that under conditions tested, 1 or 3% peroxyacetic acid solutions are equally effective as 20 000 ppm of Ca(OCl)₂ in the reduction of Salm. Stanley on alfalfa seed when used in conjunction with a commercial seed washer. Significance and Impact of the Study: A 1% peroxyacetic acid solution could potentially be used in place of 20 000 ppm of Ca(OCl)₂ for treatment of seeds used for sprouting_. The commercial seed washer did not enhance removal of Salm. Stanley from alfalfa seeds, but did facilitate removal of excess soil from seeds.     

A new species ofAdenophora (Campanulaceae) from Korea

Adenophora erecta S. Lee, J. Lee et S. Kim, is described as a new species from an open north-facing mountain slope on the coast of Sukpo-Dong, Ullungdo Is., Kyungsangbukdo, Korea. This species resemblesA. remotiflora Miq., but is well separated by having the leaves compactly arranged along the upper part of the stem, condensed raceme, distinct veins on the corolla and especially shallow dome-shaped epigynous nectar disc.     

Human brain cortex: mitochondrial oxidative damage and adaptive response in Parkinson disease and in dementia with Lewy bodies

Frontal cortex samples from frozen human brains were used to assess tissue respiration; content of mitochondria; mitochondrial oxygen uptake; activity of respiratory complexes and of mitochondrial nitric oxide synthase (mtNOS); content of cytochromes a, b, and c; oxidative damage (protein carbonyls and TBARS); and expression of Mn-SOD in patients with Parkinson disease (PD) and with dementia with Lewy bodies (DLB) in comparison with those of normal healthy controls. Brain cortex and mitochondrial O₂ uptake and complex I activity were significantly lower in PD and DLB, whereas mtNOS activity, cytochrome content, expression of Mn-SOD, mitochondrial mass, and oxidative damage were significantly higher in the frontal cortex in PD and DLB. The decreases in tissue and mitochondrial O₂ uptake and in complex I activity are considered the consequences of mitochondrial oxidative damage. The increases in mtNOS activity and in mitochondrial mass are interpreted as an adaptive response of the frontal cortex that involves increased NO signaling for mitochondrial biogenesis. The adaptive response would partially compensate for mitochondrial dysfunction in these neurodegenerative diseases and would afford a human evolutionary response to shortage of ATP in the frontal cortex.     

Dendritic reorganization in pyramidal neurons in medial prefrontal cortex after chronic corticosterone administration

Chronic stress produces deficits in cognition accompanied by alterations in neural chemistry and morphology. For example, both stress and chronic administration of corticosterone produce dendritic atrophy in hippocampal neurons (Woolley C, Gould E, McEwen BS. 1990. Exposure to excess glucocorticoids alters dendritic morphology of adult hippocampal pyramidal neurons. Brain Res 531:225–231; Watanabe Y, Gould E, McEwen BS, 1992b. Stress induces atrophy of apical dendrites of hippocampal CA3 pyramidal neurons. Brain Res 588:341–345). Prefrontal cortex is also a target for glucocorticoids involved in the stress response (Meaney MJ, Aitken DH. 1985. [³H]Dexamethasone binding in rat frontal cortex. Brain Res 328:176–180); it shows neurochemical changes in response to stress (e.g., Luine VN, Spencer RL, McEwen BS. 1993. Effect of chronic corticosterone ingestion on spatial memory performance and hippocampal serotonergic function. Brain Res 616:55–70; Crayton JW, Joshi I, Gulati A, Arora RC, Wolf WA. 1996. Effect of corticosterone on serotonin and catecholamine receptors and uptake sites in rat frontal cortex. Brain Res 728:260–262; Takao K, Nagatani T, Kitamura Y, Yamawaki S. 1997. Effects of corticosterone on 5‐HT_1A and 5‐HT₂ receptor binding and on the receptor‐mediated behavioral responses of rats. Eur J Pharmacol 333:123–128; Sandi C, Loscertales M. 1999. Opposite effects on NCAM expression in the rat frontal cortex induced by acute vs. chronic corticosterone treatments. Brain Res 828:127–134), and mediates many of the behaviors that are altered by chronic corticosterone administration (e.g., Lyons DM, Lopez JM, Yang C, Schatzberg AF. 2000. Stress‐level cortisol treatment impairs inhibitory control of behavior in monkeys. J Neurosci 20:7816–7821). To determine if glucocorticoid‐induced morphological changes also occur in medial prefrontal cortex, the effects of chronic corticosterone administration on dendritic morphology in this corticolimbic structure were assessed. Adult male rats received s.c. injections of either corticosterone (10 mg in 250 μL sesame oil; n = 8) or vehicle (250 μL; n = 8) daily for 3 weeks. A third group of rats served as intact controls (n = 4). Brains were stained using a Golgi‐Cox procedure and pyramidal neurons in layer II‐III of medial prefrontal cortex were drawn; dendritic morphology was quantified in three dimensions. Sholl analyses demonstrated a significant redistribution of apical dendrites in corticosterone‐treated animals: the amount of dendritic material proximal to the soma was increased relative to intact rats, while distal dendritic material was decreased relative to intact animals. Thus, chronic glucocorticoid administration dramatically reorganized apical arbors in medial prefrontal cortex. This reorganization likely reflects functional changes and may contribute to stress‐induced changes in cognition. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 245–253, 2001     

Seasonal stability of sulfuric acid accumulation in the Dictyotales (Phaeophyceae)

Concerning the accumulation of S0₄^2‐ in cells, three types of species are known in the Dictyotales: (i) acidic type (high H₂S0₄ accumulation); (ii) high MgS0₄ accumulation type; and (iii) nonacidic type (low S0₄^2‐ accumulation). Seasonal changes of intracellular pH and concentrations of inorganic ions were examined in six dictyotalean species. In acidic species (Dictyopteris prolifera (Okamura) Okamura and Spatoglossum eras‐sum J. Tanaka), intracellular concentrations of S0₄^2‐ and H⁺ estimated by pH were high through all seasons. In high MgS0₄ accumulating species (Dictyotasp. and Padina arborescens Holmes), intracellular concentrations of S0₄^2‐ and Mg²⁺ were high through all seasons. In nonacidic species (Dictyota dichotoma (Hudson) Lamouroux and Dictyopteris undulata Holmes), intracellular concentration of sulfuric acid ion was low all year round.     

A new FGFR inhibitor disrupts the TGF‐β1‐induced fibrotic process

Pulmonary fibrosis (PF) is chronic and irreversible damage to the lung characterized by fibroblast activation and matrix deposition. Although recently approved novel anti‐fibrotic agents can improve the lung function and survival of patients with PF, the overall outcomes remain poor. In this study, a novel imidazopurine compound, 3‐(2‐chloro‐6‐fluorobenzyl)‐1,6,7‐trimethyl‐1H‐imidazo[2,1‐f]purine‐2,4(3H,8H)‐dione (IM‐1918), markedly inhibited transforming growth factor (TGF)‐β‐stimulated reporter activity and reduced the expression of representative fibrotic markers, such as connective tissue growth factor, fibronectin, collagen and α‐smooth muscle actin, on human lung fibroblasts. However, IM‐1918 neither decreased Smad‐2 and Smad‐3 nor affected p38MAPK and JNK. Instead, IM‐1918 reduced Akt and extracellular signal‐regulated kinase 1/2 phosphorylation increased by TGF‐β. Additionally, IM‐1918 inhibited the phosphorylation of fibroblast growth factor receptors 1 and 3. In a bleomycin‐induced murine lung fibrosis model, IM‐1918 profoundly reduced fibrotic areas and decreased collagen and α‐smooth muscle actin accumulation. These results suggest that IM‐1918 can be applied to treat lung fibrosis.     

A role for gibberellic acid in orienting microtubules and regulating cell growth polarity in the maize root cortex

The role of gibberellins and cortical microtubules in determining the polarity of cell growth in the root cortex of maize (Zea mays L.) was examined. Inhibition of gibberellin biosynthesis, either naturally through mutation (d5 mutant) or by means of chemicals such as 2S,3S paclobutrazol, caused thickening of root apices and increased their starch content. Immunofluorescence microscopy of cortical microtubules, coupled with a comparison of cell widhts, lengths and shapes, indicated that the meristem and immediate post-mitotic zone were the targets of gibberellin deficiency. Cortical cells in these regions were impaired in their ability to develop highly ordered transversal arrays of cortical microtubules. Consequently, the cells became wider and shorter. Application of gibberellic acid re-established the arrangements of cortical microtubules and the polarity of cell growth characteristic for roots having normal levels of gibberellins, it also decreased the starch content. These results indicate that gibberellins are morphogenetically active substances, not only in shoots but also in roots of maize.Abbreviations CMT cortical microtubule - GA gibberellin - GA₃ gibberellic acid - MT microtubule - PIG postmitotic isodiametric growth The authors acknowledge the support to F.B. from the Royal Society (London UK). We also thank Dr. J. Lenton (University of Bristol, Long Ashton Research Station) who kindly supplied us with 2S,3S paclobutrazol and grains of the GA-deficient d5 mutant of maize.     

Separation of Enantiomers by Inclusion Gas Chromatography: On the Influence of Water in the Molecular Complexation of Methyl 2‐Chloropropanoate Enantiomers and the Modified γ‐Cyclodextrin Lipodex‐E

A profound influence of water has previously been detected in the complexation of the enantiomers of methyl 2‐chloropropanoate (MCP) and the chiral selector octakis(3‐O‐butanoyl‐2,6‐di‐O‐pentyl)‐γ‐cyclodextrin (Lipodex‐E) in NMR and sensor experiments. We therefore investigated the retention behavior of MCP enantiomers on Lipodex‐E by gas chromatography (GC) under hydrous conditions. Addition of water to the N₂ carrier gas modestly reduced the retention factors k of the enantiomers, notably for the second eluted enantiomer (S)‐MCP. This resulted in an overall decrease of enantioselectivity ‐Δ_S,R(ΔG) in the presence of water. The effect was fully reversible. Consequently, for a conditioned column in the absence of residual water, the determined thermodynamic data, i.e. Δ_S,R(ΔH) = –12.64 ± 0.08 kJ mol^‐1 and Δ_S,R(ΔS) = –28.18 ± 0.23 J K^‐1 mol^‐1, refer to a true 1:1 complexation process devoid of hydrophobic hydration. Chirality 28:124–131, 2015. © 2015 Wiley Periodicals, Inc.