Hominin Dispersal into the Nefud Desert and Middle Palaeolithic Settlement along the Jubbah Palaeolake,Northern Arabia

The Arabian Peninsula is a key region for understanding hominin dispersals and the effect of climate change on prehistoric demography, although little information on these topics is presently available owing to the poor preservation of archaeological sites in this desert environment. Here, we describe the discovery of three stratified and buried archaeological sites in the Nefud Desert, which includes the oldest dated occupation for the region. The stone tool assemblages are identified as a Middle Palaeolithic industry that includes Levallois manufacturing methods and the production of tools on flakes. Hominin occupations correspond with humid periods, particularly Marine Isotope Stages 7 and 5 of the Late Pleistocene. The Middle Palaeolithic occupations were situated along the Jubbah palaeolake-shores, in a grassland setting with some trees. Populations procured different raw materials across the lake region to manufacture stone tools, using the implements to process plants and animals. To reach the Jubbah palaeolake, Middle Palaeolithic populations travelled into the ameliorated Nefud Desert interior, possibly gaining access from multiple directions, either using routes from the north and west (the Levant and the Sinai), the north (the Mesopotamian plains and the Euphrates basin), or the east (the Persian Gulf). The Jubbah stone tool assemblages have their own suite of technological characters, but have types reminiscent of both African Middle Stone Age and Levantine Middle Palaeolithic industries. Comparative inter-regional analysis of core technology indicates morphological similarities with the Levantine Tabun C assemblage, associated with human fossils controversially identified as either Neanderthals or Homo sapiens.     

Evidence for a circulating sodium transport inhibitor in essential hypertension.

The active sodium transport of white cells and red cells obtained from patients with essential hypertension was impaired. Incubating white cells from normotensive subjects in serum obtained from patients with essential hypertension caused an impairment in sodium transport in the white cells of normotensive subjects similar to that found in the white cells of hypertensive patients. The impairment in sodium transport was due to a fall in the ouabain-sensitive component of the total sodium efflux rate constant. These results show that the serum of patients with essential hypertension contains a substance which influences sodium transport and that it has ouabain-like activity. They also suggest that it is this substance which causes the impairment in sodium transport in the leucocytes of patients with essential hypertension. These findings support the hypothesis that the rise in blood pressure in patients with essential hypertension is due to an increased concentration of a circulating sodium transport inhibitor which is continuously correcting a tendency for sodium retention by the kidney.     

Exclusion of deceased donors post-procurement of tissues

The EU Tissues and Cells Directive (2004/23/EC, 2006/17/EC, 2006/86/EC) (EUTCD) provides standards for quality and safety for all aspects of banking of tissues and cells for clinical applications. Commission Directive 2006/17/EC stipulates that the complete donor record with all the medical information is assessed for suitability before releasing tissues for clinical use. The aim of this study was to investigate the medical reasons for post-procurement donor exclusion, to identify the various potential sources for gathering information about donors’ medical and behavioural history and to evaluate their contribution to maximising the safety of donations. Information was collected from the Tissue Services (TS) records of 1000 consecutive deceased donors submitted to National Health Service Blood and Transplant (NHSBT) medical officers for authorisation for release for subsequent tissue processing and then for transplantation. Of the 1000 donors 60 (6%) were excluded because they did not fulfil the donor selection requirements of the EUTCD and NHSBT donor selection guidelines. The main reasons for medical exclusion were the presence of significant local or systemic infection in 32 donors (53% of those excluded for medical reasons) and a history of past or occult malignancy in 9 donors (15% of those excluded for medical reasons) which was not identified prior to procurement. The information leading to post-procurement exclusion was obtained from autopsy reports in 35 of the 60 excluded donors for medical reasons (58%) and from the general practitioner for 10 donors (17% of those excluded for medical reasons). In summary, careful evaluation of complete donor records reduces the potential risk of disease transmission by tissue allografts and ensures compliance with regulations and guidelines. The findings may lead to changes in donor selection policies with the aim of improving efficiency without compromising safety.     

Increased rigidity of eglin c at acidic pH: evidence from NMR spin relaxation and MD simulations

To gain physical insights into how proteins respond to changes in pH, the picosecond to nanosecond time scale dynamics of the small serine protease inhibitor eglin c have been studied by NMR spin relaxation experiments and MD simulations under two pH solution conditions, pH 7 and 3. Like many proteins, eglin c is destabilized by a lowering of the pH, although it retains enough stability to maintain its native conformation at pH 3. Backbone (15)N relaxation results show comparable global tumbling times (tau(m)) and model-free order parameters (S(2)) under the two pH conditions, indicating that the molecule maintains its overall molecular shape and structure at low pH, although the backbone rigidity is slightly increased (/ = 0.6%). In contrast, the side-chain methyl dynamics, as measured from (2)H relaxation experiments, show a substantial increase in rigidity at lower pH (/ = 14.8%). Molecular dynamics simulations performed at these pH states produce results consistent with NMR measurements, showing that the two methods are in qualitative agreement. Although a full accounting of the physical basis for the concurrent conformational rigidification and destabilization at low pH requires further investigation, the high level of detail in the MD simulations provides a potential molecular mechanism: the breaking of the hydrogen bond between the side chains of Asp46 and Arg53, and changes in electrostatic interactions, appear to allow the binding loop to move closer to the core part of the protein, resulting in a more compact structure at low pH. This more compact structure may be responsible for the increased level of restriction of molecular motion. As these findings show, the stability of a molecular structure is distinct from its conformational rigidity, and the two can even change in opposite directions, against na?ve expectation.     

Volatiles from biofumigant plants have a direct effect on carpogenic germination of sclerotia and mycelial growth of <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>

Aims

Sclerotia of Sclerotinia sclerotiorum survive in soil and germinate to produce apothecia which release airborne ascospores. Current control methods rely predominantly on the use of fungicides to kill ascospores. The aim of this research was to identify potential biofumigation treatments which suppress sclerotial germination, providing a potential alternative and long-term approach to disease management.

Methods

Microcosm and in vitro experiments were conducted using dried and milled plant material from six different biofumigant crop plants to determine effects on carpogenic germination of sclerotia and mycelial growth of S. sclerotiorum.

Results

All biofumigant plants significantly reduced germination of S. sclerotiorum sclerotia in the microcosm experiments, but were less effective against larger sclerotia. In vitro experiments showed a direct effect of biofumigant volatiles on both the mycelial growth of S. sclerotiorum, and carpogenic germination of sclerotia, where the most effective treatment was B. juncea ‘Vittasso’.

Conclusions

It was clear from this study that biofumigant crop plants have potential as part of an integrated disease management system for control of S. sclerotiorum. The microcosm experiments described here provide a straightforward and reliable screening method for evaluating different biofumigants for activity.

     

Environmental temperature versus spontaneous running—wheel activity in the red squirrel,TAMIASCIURUS HUDSONICUS

The effect of ambient temperature on the daily running activity of the red squirrel TAMIASCIURUS HUDSONICUS was investigated. Running-wheel activity (min/day) of live-trapped male and female animals was monitored for 7 days in the laboratory after 10–16 days adaptation at environmental temperatures of 10°, 20°, 30° and 35°C and the mean daily activity correlated with T_a. The data show that activity and environmental temperature are inversely related. It is believed that the level of spontaneous running-wheel activity at these temperatures is a function of the heat balance of the animal.

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Zusammenfassung Die Wirkung der Umgebungstemperatur auf die Laufaktivität des Rothörnches, TAMIASCIURUS HUDSONICUS wurde im Laboratorium untersucht. Die Laufaktivität (Min./Tag) von lebend gefangenen männlichen und weiblichen Tieren wurde in einer Temperaturkammer nach je 10–16 Tagen Anpassung nacheinander bei Umgebungstemperaturen von 10°, 20°, 30° und 35°C als Mittel aus 7 Tagen-Versuche berechnet und mit der Temperatur korreliert. Die Werte zeigen, dass die Umgebungstemperatur und spontane Laufaktivität negativ korreliert sind. Es wird die Auffassung vertreten, dass das Ausmass der Laufaktivität bei diesen Temperaturen eine Funktion des Wärmegleichgewichtes der Tiere ist.

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Resume On a observé en laboratoire les effets de la température ambiante sur les déplacements de l'écureuil roux (TAMIASCIURUS HUDSONICUS). Pour l'expérience, on a utilisé des animaux des deux sexes capturés vivants et placés successivement, après 10 à 16 jours d'adaptation, à des températures de 10°, 20°, 30° et 35°C. On a ensuite calculé la corrélation entre la moyenne journalière (en minutes/jour) de 7 jours d'exposition d'une part, la température d'autre part. Les résultats montrent que la température ambiante et l'activité déambulatoire spontanée de cette sorte d'écureuils sont en relation inverse. On pense que l'importance de cette activité est fonction, par ces températures, de l'équilibre thermique des animaux examinés.

     

Studies on the regulation of plasma cholesterol levels in squirrel monkeys of two genotypes

Certain individual squirrel monkeys ("hypo-responders") are able to remain normocholesterolemic when fed diets containing cholesterol (0.5 mg/kcal). Other squirrel monkeys ("hyperresponders") when fed the same diet become hypercholesterolemic. The purpose of these studies was to identify the mechanisms which allow hyporesponders to compensate for dietary cholesterol. Using formula diets and sterol balance techniques, we have compared cholesterol absorption, synthesis, excretion, and turnover in hypo- and hyperresponding monkeys. Cholesterol absorption was essentially identical in the two groups (about 55 mg/day). Cholesterol synthesis was likewise similar in the two groups (about 35 mg/day) and there was no evidence of feedback inhibition at the level of cholesterol fed. Hyporesponders had faster turnover rates and smaller body cholesterol pools than did hyperresponders. Excretion of neutral steroids was similar for hypo- and hyperresponders and did not change with cholesterol feeding. In contrast, hyporesponders increased bile acid excretion shortly after cholesterol feeding was begun. Hyperresponders responded more slowly and to a lesser degree. It is concluded that, in this species, the mechanism of control of plasma cholesterol levels is related to the rate of conversion of cholesterol to bile acids.     

Classical Noncholinergic Neurotransmitters and the Vesicular Transport System for Acetylcholine

Abstract: The acetylcholine transporter exhibits such low affinity and specificity for acetylchoiine that it appeared possible it could fail to select against other neurotransmitters. Potential interactions of classical noncholinergic neurotransmitters with cholinergic synaptic vesicles purified from electric organ were studied. No active transport of [³H]serotonin, [³H]noradrenaline, or [³H]glutamate occurred. Serotonin, noradrenaline, and N -acetylaspartyl glutamate inhibited active transport of [³H]acetylcholine by the vesicles. Dopamine previously had been shown to inhibit transport. Glutamate and γ-aminobutyric acid were shown here not to inhibit active transport of [³H]-acetylcholine. Noradrenaline was competitive with respect to [³H]acetylcholine in this effect. Serotonin, noradrenaline, and dopamine inhibited binding of [³H]vesamicol to the vesicles, and dopamine was a competitive inhibitor of the binding of this allosteric ligand of the acetylcholine transporter. The results indicate that the acetylcholine transporter does not transport any other classical neurotransmitter, but serotonin, noradrenaline, and dopamine bind to the acetylcholine site.     

Effects of repeated creatine supplementation on muscle, plasma, and urine creatine levels

The purpose of this case study was to examine the effects of repeated creatine administration on muscle phosphocreatine, plasma creatine, and urine creatine. One male subject (age, 32 years; body mass, 78.4 kg; height, 160 cm; resistance training experience, 15 years) ingested creatine (20 g.d(-1) for 5 days) during 2 bouts separated by a 30-day washout period. Muscle phosphocreatine was measured before and after supplementation. On day 1 of supplementation, blood samples were taken immediately before and hourly for 5 hours following ingestion of 5 g of creatine, and a pharmacokinetic analysis of plasma creatine was conducted. Twenty-four-hour urine collections were conducted before and for 5 days during supplementation. Muscle phosphocreatine increased 45% following the first supplementation bout, decreased 22% during the 30-day washout period, and increased 25% following the second bout. There were no meaningful differences in plasma creatine pharmacokinetic parameters between bouts 1 and 2. Total urine creatine losses during supplementation were 63.2 and 63.4 g during bouts 1 and 2, respectively. The major findings were that (a) a 30-day washout period is insufficient time for muscle phosphocreatine to return to baseline following creatine supplementation but is sufficient time for plasma and urine creatine levels to return to presupplementation values; (b) postsupplementation muscle phosphocreatine levels were similar following bouts 1 and 2 despite 23% higher presupplementation muscle phosphocreatine before bout 2; and (c) the increased muscle phosphocreatine that persisted throughout the 30-day washout period corresponded with maintenance of increased body mass (+2.0 kg). Athletes should be aware that the washout period for muscle creatine to return to baseline levels may be longer than 30 days in some individuals, and this may be accompanied by a persistent increase in body mass.     

Rapid hypotonic method for flow cytofluorometry of monolayer cell cultures. Some pitfalls in staining and data analysis.

The rapid hypotonic staining procedure developed by Krishan for DNA determinations by flow cytofluorometry has been proven accurate for in vivo cell samples and for cell lines growing in suspension culture. We show that the unmodified procedure may produce distorted DNA histograms when used for staining cells growing in monolayer cultures, however. To eliminate these distortions, it was necessary to avoid the use of trypsin by staining the attached cells directly, using a hypotonic fluorochrome solution to which nonionic detergent was added. Two sublines of HeLa S3 cells are shown to exhibit major differences in their staining characteristics. By using our revised staining procedure, the two sublines appear to produce very satisfactory DNA histograms. However, in only one subline does the S phase fraction calculated from the histograms agree with the autoradiographical labeling index. Mitotic cells remain intact under these staining conditions, and the principal observed effect of nonionic detergents in this case is to decrease the coefficient of variation of fluorescence intensity.