52 research outputs found
Body mass estimation from footprint size in hominins.
Although many studies relating stature to foot length have been carried out, the relationship between foot size and body mass remains poorly understood. Here we investigate this relationship in 193 adult and 50 juvenile habitually unshod/minimally shod individuals from five different populations-Machiguenga, Daasanach, Pumé, Hadzabe, and Samoans-varying greatly in body size and shape. Body mass is highly correlated with foot size, and can be predicted from foot area (maximum length × breadth) in the combined sample with an average error of about 10%. However, comparisons among populations indicate that body shape, as represented by the body mass index (BMI), has a significant effect on foot size proportions, with higher BMI samples exhibiting relatively smaller feet. Thus, we also derive equations for estimating body mass from both foot size and BMI, with BMI in footprint samples taken as an average value for a taxon or population, estimated independently from skeletal remains. Techniques are also developed for estimating body mass in juveniles, who have relatively larger feet than adults, and for converting between foot and footprint size. Sample applications are given for five Pliocene through Holocene hominin footprint samples from Laetoli (Australopithecus afarensis), Ileret (probable Homo erectus), Happisburgh (possible Homo antecessor), Le Rozel (archaic Homo sapiens), and Barcin Höyük (H. sapiens). Body mass estimates for Homo footprint samples appear reasonable when compared to skeletal estimates for related samples. However, estimates for the Laetoli footprint sample using the new formulae appear to be too high when compared to skeletal estimates for A. afarensis. Based on the proportions of A.L. 288-1, this is apparently a result of relatively large feet in this taxon. A different method using a ratio between body mass and foot area in A.L. 288-1 provides estimates more concordant with skeletal estimates and should be used for A. afarensis
Freeze-Dried Somatic Cells Direct Embryonic Development after Nuclear Transfer
The natural capacity of simple organisms to survive in a dehydrated state has long been exploited by man, with lyophylization the method of choice for the long term storage of bacterial and yeast cells. More recently, attempts have been made to apply this procedure to the long term storage of blood cells. However, despite significant progress, practical application in a clinical setting is still some way off. Conversely, to date there are no reports of attempts to lyophilize nucleated somatic cells for possible downstream applications. Here we demonstrate that lyophilised somatic cells stored for 3 years at room temperature are able to direct embryonic development following injection into enucleated oocytes. These remarkable results demonstrate that alternative systems for the long-term storage of cell lines are now possible, and open unprecedented opportunities in the fields of biomedicine and for conservation strategies
Presence of intestinal Mycobacterium avium subspecies paratuberculosis (MAP) DNA is not associated with altered MMP expression in ulcerative colitis
<p>Abstract</p> <p>Background</p> <p><it>Mycobacterium avium </it>subspecies <it>paratuberculosis </it>(MAP) is suspected to be a causative agent in human Crohn's disease (CD). Recent evidence suggests that pathogenic mycobacteria and MAP can induce the expression of Matrix Metalloproteinases (MMP), which are the main proteases in the pathogenesis of mucosal ulcerations in inflammatory bowel disease (IBD). Within this study we assessed the prevalence of intestinal MAP specific DNA in patients with Crohn's disease, ulcerative colitis (UC), and healthy controls. We further analysed regulation patterns of MMPs in mucosal tissues of UC patients with and without intestinal MAP DNA detection.</p> <p>Methods</p> <p>Colonic biopsy samples were obtained from 63 Norwegian and German IBD patients and 21 healthy controls. RNA was quantified by quantitative real-time polymerase chain reaction (PCR) to study MMP gene expression in both pathological and healthy mucosal specimens. The presence of MAP DNA in colonic mucosa was examined using MAP specific PCR.</p> <p>Results</p> <p>MAP DNA was detected in 20% of UC patients and 33% of healthy controls but only in 7% of patients with CD. UC patients treated with corticosteroids exhibited a significantly increased frequency of intestinal MAP DNA compared to those not receiving corticosteroids. Expression of MMP-1, -2, -7, -9, -13, -19, -28 and TNF-α did not differ between UC patients with presence of intestinal MAP DNA compared to those without. MMP-2, MMP-9 and MMP-13 were significantly decreased in UC patients receiving corticosteroids.</p> <p>Conclusions</p> <p>The presence of intestinal MAP specific DNA is not associated with altered MMP expression in UC <it>in vivo</it>. Corticosteroids are associated with increased detection of intestinal MAP DNA and decreased expression of certain MMPs. Frequent detection of MAP DNA in healthy controls might be attributable to the wide environmental distribution of MAP and its presence in the food-chain.</p
The tumour suppressor RASSF1A promotes MDM2 self-ubiquitination by disrupting the MDM2–DAXX–HAUSP complex
Electrostatically Targeted Intermembrane Lipid Exchange with Micropatterned Supported Membranes †
Label-Free Molecular Observations of Membrane-Associated Species using Backscattering Interferometry
The influence of reproductive status on rural Kenyan women's time use
To determine the effects that pregnancy and infant care have on Embu women's commercial, agricultural and household activities, time use patterns were studied for women at different stages of pregnancy and lactation. Time allocation data were collected from 169 households, visited at random intervals over a year, by use of the spot observations technique. Detailed reproductive data were collected monthly, and household socioeconomic data quarterly. Analyses of Embu women's time use by reproductive status reveal that the demands of pregnancy and lactation require women to decrease the amount of time spent on subsistence agriculture, commercial activities, housework, and tending animals; and to devote more time to resting, breastfeeding, and child care. Agricultural and economic activities are curtailed especially in the 3rd trimester of pregnancy and the 1st period of lactation. This data provide insight into how pregnancy and lactation require women to adjust their time allocation between reproductive and farm labor activities. This decrease in time spent on subsistence agriculture, commercial activities, and household work increases the risk of household economic insecurity during the woman's reproductive years.reproductive status time allocation Kenya rural women
Neuronal Activation by GPI-Linked Neuroligin-1 Displayed in Synthetic Lipid Bilayer Membranes
Direct Measurement of Trafficking of the Cystic Fibrosis Transmembrane Conductance Regulator to the Cell Surface and Binding to a Chemical Chaperone
Mutations
in the cystic fibrosis transmembrane conductance regulator
(CFTR) result in the disease cystic fibrosis. Deletion of Phe508,
the most prevalent mutation associated with this disease, disrupts
trafficking of the protein. Small molecule correctors yield moderate
improvements in the trafficking of ΔF508-CFTR to the plasma
membrane. It is currently not known if correctors increase the level
of trafficking through improved cargo loading of transport vesicles
or through direct binding to CFTR. Real-time measurements of trafficking
were utilized to identify the mechanistic details of chemical, biochemical,
and thermal factors that impact CFTR correction, using the corrector
molecule VX-809, a secondary mutation (I539T), and low-temperature
conditions. Each individually improved trafficking of ΔF508-CFTR
to approximately 10% of wild-type levels. The combination of VX-809
with either low temperature or the I539T mutation increased the amount
of CFTR on the plasma membrane to nearly 40%, indicating synergistic
activity. The number of vesicles reaching the surface was significantly
altered; however, the amount of channel in each vesicle remained the
same. Direct binding measurements of VX-809 in native membranes using
backscattering interferometry indicate tight binding to CFTR, which
occurred in a manner independent of mutation. The similar values obtained
for all forms of the channel indicate that the binding site is not
compromised or enhanced by these mutations
Membrane Association Dictates Ligand Specificity for the Innate Immune Receptor NOD2
The
human gut must regulate its immune response to resident and
pathogenic bacteria, numbering in the trillions. The peptidoglycan
component of the bacterial cell wall is a dense and rigid structure
that consists of polymeric carbohydrates and highly cross-linked peptides
which offers protection from the host and surrounding environment.
Nucleotide-binding oligomerization domain-containing protein 2 (NOD2),
a human membrane-associated innate immune receptor found in the gut
epithelium and mutated in an estimated 30% of Crohn’s disease
patients, binds to peptidoglycan fragments and initiates an immune
response. Using a combination of chemical synthesis, advanced analytical
assays, and protein biochemistry, we tested the binding of a variety
of synthetic peptidoglycan fragments to wild-type (WT)-NOD2. Only
when the protein was presented in the native membrane did binding
measurements correlate with a NOD2-dependent nuclear factor kappa-light-chain-enhancer
of activated B cells (NF-κB) response, supporting the hypothesis
that the native-membrane environment confers ligand specificity to
the NOD2 receptor for NF-κB signaling. While <i>N</i>-acetyl-muramyl dipeptide (MDP) has been thought to be the minimal
peptidoglycan fragment necessary to activate a NOD2-dependent immune
response, we found that fragments with and without the dipeptide moiety
are capable of binding <i>and</i> activating a NOD2-dependent
NF-κB response, suggesting that the carbohydrate moiety of the
peptidoglycan fragments is the minimal functional epitope. This work
highlights the necessity of studying NOD2-ligand binding in systems
that resemble the receptor’s natural environment, as the cellular
membrane and/or NOD2 interacting partners appear to play a crucial
role in ligand binding and in triggering an innate immune response
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