A raman study of the interaction of Mg2+, Ca2+, and Ba2+ ions with an acidic model membrane

The interaction of dipalmitoylphosphatidylgly cerol DPPG) liposomes with divalent ions of magnesium, calcium and barium has been investigated with laser-Raman spectroscopy over the temperature range of 0–60°C. The effect of Ca²⁺ ions was also investigated as a function of concentration. At a Ca²⁺/DPPG molar ratio of 0.1, the number of trans carbon to carbon bonds in the hydrocarbon domain of the phospholipid and the lateral order of the hydrocarbon chains was increased both below and above the gel to liquid crystal transition. At higher Ca²⁺ concentrations the number of trans bonds and the lateral order is further increased over the entire temperature range studied, while the transition disappears. Magnesium and barium ions have a much smaller ordering effect on the side-chain packing of DPPG liposomes. At a molar ratio of 0.3, the gel to liquid crystal transition is still discernible for DPPG liposomes in the presence of Ba²⁺ ions, but not in the presence of Mg²⁺ ions.     

Effects of restricted sleep with different exercise loads upon subsequent sleep

Seven male cats were adapted to different schedules of restricted sleep. The cat was permitted to go to sleep either 2, 4 or 8 hours per day with the balance to 24-h periode spent in wakefulness enforced by means of a treadmill. Two experiments were run and the same cats served in both runs. The experiments and schedules were separated by at least two weeks during which time cats were maintained under ordinary laboratory conditions. Our experiment used treadmill speed of 2.6 m/min which was easily tolerated and effective in eliminating sleep. Another experiment used treadmill speed of 4.6 m/min which produced more physical exercise. As available sleep time become progressively shorter, REM sleep increased while SWS decreased. If restriction in sleep time was associated with more physical exercise then the composition of the subsequent sleep was different : SWS increased while REM sleep decreased. The functional significance of these opposite effects are presumably different. The immediate SWS response to the prior muscular exercise is suggestive of its recovery function.     

Sleep-waking cycle and behaviour after diethyldithiocarbamate in the rat

Young adult Louis rats were implanted for chronic sleep recording to test the effect of diethyldithiocarbamate (DDC) on sleep. Recordings of EEG and EMG were done continuously for 12 h during the 12 consecutive days. There were 2 days of baseline recording, 3 days of recording with a single daily injection of placebo, 3 days of recording with a single daily injection of DDC (500 mg/kg i.p.), and 3 days of DDC withdrawal recording with placebo injection. Placebo injections did not change the proportion of time spent in different behavioural states. With daily injection of DDC there was an increase in wakefulness, no change in slow-wave sleep and elimination or drastic reduction in paradoxical sleep (PS). There was no PS rebound during the DDC withdrawal days. These results suggest that the reduction of PS produced by DDC and the absence of PS rebound may be due to a lowering in norepinephrine in the brain. In other experiments rats were injected with DDC (500 mg/kg i.p.) daily for 3 days and whole brains were analysed chemically. Norepinephrine was significantly decreased, while 5-hydroxytryptamine, 5-hydroxyindolacetic acid, dopamine and homovanilic acid were unchanged. Seizure activity appeared during relaxed wakefulness in all rats treated with DDC. Taken together it seems that lowering of brain NE is responsible for the appearance of seizure activity and also, for PS reduction. PS reduction might, per se, produce seizure activity.     

Women heterozygous for deficiency of the (p21 → pter) region of the X chromosome are fertile

Summary A woman balanced carrier of a X/15 translocation gave birth to a balanced infertile son and three unbalanced Xp- fertile daughters. This family and the other eleven cases of Xp- fertile women found in the literature demonstrate that loss of the p21 pter region of the X chromosome is compatible with fertility, probably because it leaves on Xp the region which is never inactivated.     

Estimation of beta-structure content of proteins by means of deconvolved FTIR spectra

Fourier self-deconvolution was applied to the infrared spectra of five globular proteins with a high beta-structure content and to the essentially alpha-helical protein hemoglobin. The featureless amide I' bands around 1650 cm-1 were thereby resolved into six to nine components, depending on the protein. Specific components were assigned to the beta-structure segments in each protein. The frequencies and the number of 'beta-bands' differ from one protein to another. The areas of the components were evaluated by means of a Gauss-Newton iteration procedure. It appears that the total area of the beta-bands, as a fraction of the total amide I' band area, reflects the relative beta-structure content of each protein studied.     

FSH and LH plasma levels in bitches with differences in risk for urinary incontinence

To determine whether the height of the plasma gonadotropin levels after spaying is associated with urinary incontinence, the concentrations of plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined once in 191 intact and 308 spayed bitches. The bitches were grouped according to their risk for urinary incontinence and the medians of their respective gonadotropin levels were compared. For intact anestrous bitches, the FSH- and LH-plasma concentrations were 5.2 (4, 8) ng/mL (median (Q1, Q3)) and 0.5 (0.5-0.5) ng/mL, respectively. In the first year after spaying, the gonadotropin concentrations rose significantly, then stabilised at a level around 10 times those of intact bitches (FSH 62.5 (44, 91) ng/mL; LH 6.1(4, 11) ng/mL). The plasma gonadotropin concentrations of long-term spayed (>12 months) continent bitches (n=209) were higher (FSH 66.8 (46, 104) ng/mL; LH 6.5 (4, 11) ng/mL) than in spayed incontinent bitches (n=60) (FSH 51.5 (38, 74) ng/mL; LH 5.5 (3, 8) ng/mL), the latter also had a higher body weight. Multiple regression analysis showed that the FSH-plasma concentration and not the body weight was decisive for the occurrence of urinary incontinence. The results of this study suggest that levels of gonadotropins are associated, directly or indirectly in the pathophysiology of urinary incontinence after spaying.     

Application of computerized infrared and Raman spectroscopy to conformation studies of casein and other food proteins

Summary The ability of modern biotechnology to produce new or modified proteins has outpaced current understanding of the relationship between protein structure and protein function. Resolution-enhanced infrared spectroscopy and Raman spectroscopy are excellent non-destructive techniques for investigating the secondary structure of proteins under a wide variety of conditions. The techniques yield rapid, reliable estimates of the proportion of helical structure, -strands, and turns of proteins in solution, as gels, or as solids. These methodologies can also detect subtle variations in protein conformation that frequently occur upon change of the biomolecular environment. In particular, it is possible to study structural changes which arise from alterations in pH, ionic strength, nature of solvent, and from interactions with other molecules or ions, such as another protein or Ca²⁺ ions. The first part of this paper will briefly review various important aspects of the techniques. The subsequent part describes application to structural problems of casein and other food proteins.     

Human Parechovirus 1 Infection Occurs via αVβ1 Integrin

Human parechovirus 1 (HPeV-1) (family Picornaviridae) is a global cause of pediatric respiratory and CNS infections for which there is no treatment. Although biochemical and in vitro studies have suggested that HPeV-1 binds to αVβ1, αVβ3 and αVβ6 integrin receptor(s), the actual cellular receptors required for infectious entry of HPeV-1 remain unknown. In this paper we analyzed the expression profiles of αVβ1, αVβ3, αVβ6 and α5β1 in susceptible cell lines (A549, HeLa and SW480) to identify which integrin receptors support HPeV-1 internalization and/or replication cycle. We demonstrate by antibody blocking assay, immunofluorescence microscopy and RT-qPCR that HPeV-1 internalizes and replicates in cell lines that express αVβ1 integrin but not αVβ3 or αVβ6 integrins. To further study the role of β1 integrin, we used a mouse cell line, GE11-KO, which is deficient in β1 expression, and its derivate GE11-β1 in which human integrin β1 subunit is overexpressed. HPeV-1 (Harris strain) and three clinical HPeV-1 isolates did not internalize into GE11-KO whereas GE11-β1 supported the internalization process. An integrin β1-activating antibody, TS2/16, enhanced HPeV-1 infectivity, but infection occurred in the absence of visible receptor clustering. HPeV-1 also co-localized with β1 integrin on the cell surface, and HPeV-1 and β1 integrin co-endocytosed into the cells. In conclusion, our results demonstrate that in some cell lines the cellular entry of HPeV-1 is primarily mediated by the active form of αVβ1 integrin without visible receptor clustering.     

Mutation Rates and Discriminating Power for 13 Rapidly-Mutating Y-STRs between Related and Unrelated Individuals

Rapidly Mutating Y-STRs (RM Y-STRs) were recently introduced in forensics in order to increase the differentiation of Y-chromosomal profiles even in case of close relatives. We estimate RM Y-STRs mutation rates and their power to discriminate between related individuals by using samples extracted from a wide set of paternal pedigrees and by comparing RM Y-STRs results with those obtained from the Y-filer set. In addition, we tested the ability of RM Y-STRs to discriminate between unrelated individuals carrying the same Y-filer haplotype, using the haplogroup R-M269 (reportedly characterised by a strong resemblance in Y-STR profiles) as a case study. Our results, despite confirming the high mutability of RM Y-STRs, show significantly lower mutation rates than reference germline ones. Consequently, their power to discriminate between related individuals, despite being higher than the one of Y-filer, does not seem to improve significantly the performance of the latter. On the contrary, when considering R-M269 unrelated individuals, RM Y-STRs reveal significant discriminatory power and retain some phylogenetic signal, allowing the correct classification of individuals for some R-M269-derived sub-lineages. These results have important implications not only for forensics, but also for molecular anthropology, suggesting that RM Y-STRs are useful tools for exploring subtle genetic variability within Y-chromosomal haplogroups.     

mtDNA variability in two Bantu‐speaking populations (Shona and Hutu) from Eastern Africa: Implications for peopling and migration patterns in sub‐Saharan Africa

In this study, we report novel data on mitochondrial DNA in two of the largest eastern Bantu‐speaking populations, the Shona from Zimbabwe and the Hutu from Rwanda. The goal is to evaluate the genetic relationships of these two ethnic groups with other Bantu‐speaking populations. Moreover, by comparing our data with those from other Niger‐Congo speaking populations, we aim to clarify some aspects of evolutionary and demographic processes accompanying the spread of Bantu languages in sub‐Saharan Africa and to test if patterns of genetic variation fit with models of population expansion based on linguistic and archeological data. The results indicate that the Shona and Hutu are closely related to the other Bantu‐speaking populations. However, there are some differences in haplogroup composition between the two populations, mainly due to different genetic contributions from neighboring populations. This result is confirmed by estimates of migration rates which show high levels of gene flow not only between pairs of Bantu‐speaking populations, but also between Bantu and non‐Bantu speakers. The observed pattern of genetic variability (high genetic homogeneity and high levels of gene flow) supports a linguistic model suggesting a gradual spread of Bantu‐speakers, with strong interactions between the different lines of Bantu‐speaker descent, and is also in agreement with recent archeological findings. In conclusion, our data emphasize the role that population admixture has played at different times and to varying degrees in the dispersal of Bantu languages. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.