Etude par Spectroscopie Infrarouge de la Transformation Hélice—Chaine Statistique des Polypeptides. I. Etude Comparée de l'Interaction de la Poly-L-alanine et d'un Amide Modèle avec l'Acide Trifluoroacétique

Infrared spectra of poly-L -alanine in trifluoroacetic acid-chloroform mixtures have been investigated and compared with those of a model amide (N-methylacetamide). The purpose of this work is to determine the nature of peptide-acid specific interactions responsible for the helix-random coil transition of polymer chains. Analysis is made in using amide (A, I, II, III) and acid (νC?O, νOH) vibrations which are specially sensitive to molecular interactions. We examined a model compound to determine the spectral characteristics of the different complexes or species formed between amide and acid. At a low acid concentration, hydrogen-bonded complexes: ? (NH) C?O…?HOOCCF₃ (1) are evidenced but no association between amide NH and acid CO groups (complexes A) is observed. For higher acid concentrations complexes (I) are progressively changed into ions pairs and free ions, which result from amide protonation by acid, according to the exothermic equilibrium (I)?? (NH)COH⁺, ^?OOCCF₃(II). Amidium and carboxylate bands are localized between 1680–1705 cm^?1 and 1620–1625 cm^?1, respectively. If the cation band is always clearly seen, the anion band is only observed for the most acidic solutions. For the polymer, a gradual complexation of type (I) is observed for all acid concentrations. From our results, the assumption of an (A) type interaction seems very unlikely but cannot be excluded. Moreover, proton transfer—similar to that observed with a model amide—is never evidenced since, in particular, the amidium band characteristic of protonation is never seen. In contrast to previous investigations, we conclude that the helix-random coil transition of polypeptides is not due to the protonation of the peptide functions. This transition does suggest a strong interaction by hydrogen bonds between polymer and acid molecules.     

Reviews

Book reviewed in this article: Molecules and Morphology in Evolution: Conflict or Compromise? —Edited by Colin Patterson. 1987. Molecules and morphology in evolution: conflict or compromise? —Colin Patterson (ed.). Zoogeography of Caribbean Insects. —James K. Liebherr (ed.). 1988.     

The Structure of the Individual Mental Lexicon from the Standpoint of L. S. Vygotsky's Ideas

Research on the structure of an individual's mental lexicon has shown that, among the set of concepts belonging to a single semantic field, there is typically one particular concept that stands out. The processes of storage, identification, and retrieval of this concept are faster and more successful than they are for the others. For example, in the vertical hierarchy of the concept fruit—apple—antonovka [McIntosh to give a familiar U. S. example—Trans.], apple plays this type of lead role and also occupies the most prominent position in the horizontal series apple—pear—plum—cherries—orange. Concepts with such characteristics are referred to as basic, source, or primary concepts. What is the reason for their special status?     

Low temperature infrared spectra of polyglycines and C--H...O==C hydrogen bonding in polyglycine II

Infrared spectra of polyglycines I and II obtained at ?170°C. have been compared with those obtained at room temperature. The changes in frequency of some of the C—H stretching bands are consistent with the earlier suggestion that C—H …? O?C hydrogen bonds are present in the structure of polyglycine II.     

New techniques in female pudendal somatosensory evoked potential testing

Objective—The primary nerves innervating the female genitalia are the dorsal nerve of the clitoris (DNC) and the perineal nerve, which innervate the clitoris and the external genitalia/distal vagina, respectively. We describe two novel electrodiagnostic techniques for evaluating the integrity of these female genital somatosensory pathways.

Subjects and methods—Seventy-seven healthy women (mean age 29.3 years) were enrolled for this study. We performed DNC somatosensory evoked potentials (SEPs), stimulating through self-adhesive disk electrodes on either side of the clitoris. Perineal nerve SEPs were evoked through a vaginal probe. Cortical responses were measured through cup electrodes affixed to the scalp at Cpz and Fpz. Stimulus parameters were duration 0.1?ms, frequency 4.1?Hz, filters 5–5,000?Hz, at three times sensory threshold.

Results—DNC and perineal nerve SEPs from both the right and left sides were reproducible and easily discerned. The mean P1 latencies were: right DNC 39.4?ms (SD 2.8?ms), left DNC 39.3?ms (SD 3.3?ms), right perineal nerve 37.8?ms (SD 3.4?ms), left perineal nerve 37.6?ms (SD 3.1?ms). We recorded SEP responses from 90 to 92% of subjects for the DNC, and 69% for the perineal nerve.

Conclusions—We are able to evoke somatosensory potentials from the four primary somatic nerves that mediate female genital cutaneous sensation. In healthy subjects, the DNC responses are robust and maintain laterality. The perineal nerve responses are less consistently obtained, but when recorded, are easily discerned. These preliminary data provide a foundation from which to study female genital innervation, particularly as it applies to sexual function.     

Relations of Bromine,Iron, Rubidium,Strontium, and Zinc Content to Morphometric Parameters in Pediatric and Nonhyperplastic Young Adult Prostate Glands

The variation with age of the Br, Fe, Rb, Sr, and Zn mass fractions and some histological characteristics of intact prostate glands of 50 subjects aged 0–30 years was investigated by an energy-dispersive X-ray fluorescence and a quantitative morphometric analysis. Mean values?±?standard error of the mean (M?±?SΕΜ) for the mass fractions (in milligrams per kilogram wet-mass basis) of these trace elements in pre-puberty were: Br—10.5?±?1.3, Fe—28.6?±?4.1, Rb—3.05?±?0.27, Sr—0.42?±?0.08, and Zn—32.9?±?3.2. During puberty and postpuberty, when there is a significant increase in circulating androgens, the mean values were: Br—5.60?±?0.57, Fe—19.3?±?1.6, Rb—3.50?±?0.28, Sr—0.24?±?0.03, and Zn—113?±?10. Mean values (M?±?SΕΜ) of percent volumes (%) of the stroma, epithelium, and lumen in the prostate before puberty were 73.4?±?2.6, 20.4?±?1.7, and 4.45?±?0.94, respectively, versus 46.5?±?2.5, 38.5?±?1.9, and 14.9?±?1.2 during puberty and postpuberty. A significant positive correlation between the prostatic Zn and percent volume of both glandular epithelium (r?=?0.573, p?≤?0.001) and glandular lumen (r?=?0.725, p?≤?0.001) was found. For the first time, it has been demonstrated that the glandular lumen is a main pool of Zn accumulation, and that the stroma is a main pool of Br and Fe accumulation in the normal human prostate, for the age range 14 to 30 years. It was concluded that the Zn binds tightly within the prostatic fluid because the volume of glandular lumen reflects the volume of prostatic fluid.     

Anthocyanins ofImpatiens holstii

1. 1.
   Byly chromatografovány antokyany t?í typ?Impatiens holstii. Bylo zji?-těno, ?e typ A (f. nana, sorta Záre, s ?arlatovými květy) obsahuje ve stonku—gluko-sidy malvidinu, v petalech—glukosidy pelargonidinu a peonidinu, v sepalech— glukosid malvidinu a cyanidinu, v pylu—glukosidy a snad i xylosidy malvidinu; typ B (f. nana, sorta Zá?e, s ?ervenofialovými květy) obsahuje ve stonku— malvidin, v petalech—peonidin, v sepalech—malvidin a cyanidin, v pylu— malvidin; typ C (vzp?ímený typ, s ?ervenofialovými květy) obsahuje v petalech—malvidin a peonidin, v sepalech—malvidin a cyanidin, v pylu—malvidin. U typ? ? a ? eukry nebyly sledovány.     
   
   

Digest: Fossils,evolutionary models,and diatoms*

Adaptation to new environments by organisms has been and is of much interest in scientific research. Does the diatom lineage Stephanodiscus niagarae/yellowstonensis follow models compatible with adaptation to a new environment? Voje (2019) shows that in this lineage, none of the current models tested—decelerated evolution, Ornstein-Uhlenbeck, and random walk—fully explained how multiple traits—valve diameter, the number of costae, and spines per valve—evolved. More accurate models are needed to understand the evolutionary history of these diatoms.     

Olfaction and Taste: Invasive Odours and Disappearing Objects

The metaphorisation of sight and hearing, the objective senses, dominate the founding ideas, or philosophemes, of Western philosophy. The senses of taste and smell are of little relevance in the formation of conceptual knowledge or in classificatory systems; they are, by virtue of their dissolving objects, incapable of giving objective knowledge in Western metaphysics. Derrida and Ulmer developed a metaphorology that exploits the chemical basis of the subjective senses of taste and smell. The anthropology of the senses takes this questioning of metaphysics into issues of how olfaction and taste function in sociality. In the routine practices of everyday life, is olfaction able to create the sense of community that it does in rituals? Or, has the repression of smell in humanity's evolution towards ‘civilisation’ muted the connective ability of multiple odour particles? In a culture and metaphysics that presumes the separability of the self from the other and the self from the object, is there a place for senses that make a nonsense of separation and objectivity through their state of meaningful dissolution? Through philosophy's metaphorisation, has taste been stripped of its sensuousness and made a sense for aesthetics and not flavours and textures? In a metaphorics premised in judgement and discernment, can taste be a sense that founds sociality? In blurring the boundaries between self and other that are necessary to form and maintain the distinction, the dissolvability of smell and taste makes another metaphorics and other socialities possible. Of all the senses, that of smell—which is attracted without objectifying—bears clearest witness to the urge to lose oneself in and become the ‘other’. As perception and the perceived—both are united—smell is more expressive than the other senses (Horkheimer and Adorno 1979:184).     

UV-visible derivative spectroscopy under high pressure

High hydrostatic pressure affects proteins, changing their intra- or intermolecular interactions, conformation and solvation. How to detect these changes? In this paper, via some selected examples, we show the potentiality (but also the limits) of the ultraviolet derivative spectroscopy specially adapted to high pressure experiments.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

The importance of HLA typing in cases of disputed paternity

In dispute paternity, the biologists must reply to two questions: 1. Is the paternity excluded or possible? 2. If it is possible, what is its probability? Valid answers can be given, using several genetic markers, among which HLA genes are specially interesting. Looking at HLA-A, B, C, DR typing of child, mother and presumed father, we propose a method which allows a direct calculation of paternity probability. Crossing over between HLA genes in presumed father and in mother are also considered in this method. In our experience, adding the date provided by the HLA genes and other genetic markers, we obtained, either formal exclusions, or possible paternities with a probability almost always higher than 90%.     

Theory of cell lineage graphs and their application to the intestinal epithelium

Elucidation of the molecular basis of cell lineage details is a major activity of both developmental biologists and those studying renewing systems in the adult. Given this priority I was surprised to find how little theory has been developed for the main object of this work, the lineage diagram. Even simple questions like—how many different diagrams are plausible?—do not appear to have been addressed and so I decided it would be timely to try to do so here. The results are applied to the intestinal epithelium as an example with special emphasis on the interpretation of recent mutation-based lineages studies.     

Reviews

Book reviewed in this article: South African perspectives on species: an evaluation of the recognition concept: Species and Speciation .—E. S. Vrba (ed.). Mind from Matter?-an essay on evolutionary epistemology .—Max Delbrück. The structure and affinities of the Hedyloidea: a new concept of the butterflies .—M. J. Scoble.     

Mechanism of the interactions of aliphatic alcohols with bovine serum albumin in the ternary systems—1H n.m.r. study: 1. Aqueous solutions BSA-alcohols-urea

The molecular mechanism of the interaction of aliphatic alcohols (A) with bovine serum albumin (BSA) protein was studied in aqueous solutions at increasing concentrations (0–8 m) of urea (U). ¹H n.m.r. spectra of alcohols were monitored in D₂O in the control binary systems (A—U) and (A—BSA), and in the ternary systems (A—U—BSA) at pH 7.0. Marked and selective broadening of the n.m.r. lines of alcohols in the system (A—BSA) was reduced upon addition of urea, indicating that alcohols are poorly bound by urea-denaturated BSA. The reduction in the ability to associate with BSA depends on chain position of the alcohol molecule and is much higher for α-methylenes (next to ?OH) than for other proton groups. Besides this reduction seems to be a two-step phenomenon dependent upon urea concentration. The results obtained can be explained by competition in formation by the peptide linkages of a protein of the hydrogen bonds with ?OH group of alcohols or fragments of urea molecules.     

Electro weak enantioselection and the origin of life

All biomolecules are of one hand — but what determines which hand? Why is life based on L-amino acids and D-sugars rather than D-amino acids and L-sugars? We believe the symmetry-breaker could be the weak force, which causes enantiomers to differ very slightly in energy. In this paper we present our calculations of this parity-violating energy difference (PVED) for a range of important biomolecules, and in nearly all cases it is indeed the ‘natural’ enantiomer which is the more stable.     

Meaning in Nature: Organic Manufacture?

The paper examines Marcello Barbieri’s (2007) Introduction to Biosemiotics. Highlighting debate within the biosemiotic community, it focuses on what the volume offers to those who explain human intellect in relation to what Turing called our ‘physical powers.’ In scrutinising the basis of world-modelling, parallels and contrasts are drawn with other work on embodied-embedded cognition. Models dominate biology. Is this a qualitative fact or does it point to biomechanisms? In evaluating the 18 contributions, it is suggested that the answers will shape the field. First, they will decide if biochemistry and explanatory reduction can be synergised by biosemantics. Second, they will show if our intellectual powers arise from biology. Does thinking use—not a language faculty—but what Marko? and colleagues call semiosis by the living? Resolution of such issues, it is suggested, can change how we view cognition. Above all, if the biomechanists win the day, cultural models can be regarded as extending natural meaning. On such a view, biomechanisms prompt us to act and perceive as we model our own natural models. This fits Craik’s vision: intellect gives us the alphanumerical ‘symbols’ that allow thoughts to have objective validity. For the biomechanist, this is explained—not by brains alone—but, rather, by acting under the constraints of historically extended sensoria.     

Studies on the Formation and Characteristics of antibodies in frogs

Было установлсно, что — кроме темиературы — вторым решающим Фактором для осуществления образования антител является количестяо антигена и время его введения. Антитела, иолученные у лятушек, были с помощыо крахмалыюго элсктро?ореэа локалиэованы в гамма-и бетаглобулиновоо ?ракции сывороточных белков. Было установлено, что в сыворотке. лятушек и в гамма-глобулиновой ?ракции находятся приблиэиэительно те же тииы молекул, как и в сыворотке млекопитающих с приэнаками болышего количества типа 18S. Гетероагглютинины нины лягушки не теряют под влиянием меркаптоэтанола своэй активности. Было установлено также, что лягушечьи иммунные гетероагглютипины, что касаетсн агглютинации эритроцитов других яидов животных, являются совершенно специ?ическими.     

First Record of Theropod and Ornithopod Tracks and Detailed Description of Sauropod Trackways from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous) of Uruguay

The record of dinosaur tracks and trackways from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous) is described in detail: two trackways and four isolated tracks. Ichnites are preserved in sandstones of interdune facies of the Batoví (lower) Member. The interpretation herein presented indicates a sauropod affinity of the trackways, while the isolated prints are considered to have been made by an ornithopod and small theropods. The fossil record for this formation was primarily integrated by fresh-water organisms. The presence of new groups (sauropods and ornithopods) has specially contributed to the reconstruction of the terrestrial fauna, represented up until this time only by theropods.