Evidence for tissue-specific forms of glutaminyl cyclase.

Glutaminyl cyclase (QC) is responsible for the presence of pyroglutamyl residues in many neuroendocrine peptides. An examination of the bovine tissue distribution of QC immunoreactivity, enzyme activity, and mRNA confirmed that QC was abundant in brain and pituitary by all three measures. However, enzymatic activity was considerably more widespread than either immunoreactivity or mRNA, suggesting multiple enzyme forms. Partially purified QC from bovine spleen differed significantly from the known bovine pituitary QC in physical and catalytic properties. We propose that this form of glutaminyl cyclase plays a role in the posttranslational processing of constitutively secreted pGlu-containing proteins.     

Sustained Levels of FGF2 Maintain Undifferentiated Stem Cell Cultures with Biweekly Feeding

An essential aspect of stem cell culture is the successful maintenance of the undifferentiated state. Many types of stem cells are FGF2 dependent, and pluripotent stem cells are maintained by replacing FGF2-containing media daily, while tissue-specific stem cells are typically fed every 3rd day. Frequent feeding, however, results in significant variation in growth factor levels due to FGF2 instability, which limits effective maintenance due to spontaneous differentiation. We report that stabilization of FGF2 levels using controlled release PLGA microspheres improves expression of stem cell markers, increases stem cell numbers and decreases spontaneous differentiation. The controlled release FGF2 additive reduces the frequency of media changes needed to maintain stem cell cultures, so that human embryonic stem cells and induced pluripotent stem cells can be maintained successfully with biweekly feedings.     

Gastro-oesophageal reflux complicating highly selective vagotomy.

An unacceptably high incidence of gastro-oesophageal reflux was observed in a small series of patients with duodenal ulcer who had been treated by highly selective vagotomy. Possibly this is due to an altered angle of entry of the oesophagus into the stomach, and we now routinely narrow this angle at operation.     

Understanding How Noncatalytic Carbohydrate Binding Modules Can Display Specificity for Xyloglucan

Plant biomass is central to the carbon cycle and to environmentally sustainable industries exemplified by the biofuel sector. Plant cell wall degrading enzymes generally contain noncatalytic carbohydrate binding modules (CBMs) that fulfil a targeting function, which enhances catalysis. CBMs that bind β-glucan chains often display broad specificity recognizing β1,4-glucans (cellulose), β1,3-β1,4-mixed linked glucans and xyloglucan, a β1,4-glucan decorated with α1,6-xylose residues, by targeting structures common to the three polysaccharides. Thus, CBMs that recognize xyloglucan target the β1,4-glucan backbone and only accommodate the xylose decorations. Here we show that two closely related CBMs, CBM65A and CBM65B, derived from EcCel5A, a Eubacterium cellulosolvens endoglucanase, bind to a range of β-glucans but, uniquely, display significant preference for xyloglucan. The structures of the two CBMs reveal a β-sandwich fold. The ligand binding site comprises the β-sheet that forms the concave surface of the proteins. Binding to the backbone chains of β-glucans is mediated primarily by five aromatic residues that also make hydrophobic interactions with the xylose side chains of xyloglucan, conferring the distinctive specificity of the CBMs for the decorated polysaccharide. Significantly, and in contrast to other CBMs that recognize β-glucans, CBM65A utilizes different polar residues to bind cellulose and mixed linked glucans. Thus, Gln¹⁰⁶ is central to cellulose recognition, but is not required for binding to mixed linked glucans. This report reveals the mechanism by which β-glucan-specific CBMs can distinguish between linear and mixed linked glucans, and show how these CBMs can exploit an extensive hydrophobic platform to target the side chains of decorated β-glucans.     

Bioarchaeological evidence for adaptive plasticity and constraint: Exploring life‐history trade‐offs in the human past

The Developmental Origins of Health and Disease paradigm evaluates the consequences of early life stress on health at later stages of life. Interacting with this paradigm represents a profound opportunity to leverage the lifespan and contextual approaches to human skeletal remains adopted by bioarchaeological research. Teeth and bone provide evidence for stressors experienced early in life. These events represent evidence for adaptive plasticity as Individuals survive the events through reallocation of energy to essential physiological functions, which inhibits enamel and skeletal growth. Age‐at‐death, adult body size, chronic infection, or childhood mortality may be used as covariates to better understand the physiological constraints operating on individual bodies following survival of early life stress. Contextual evidence from cemeteries provides clues to the ecological and cultural contingencies that exacerbate or mitigate the expression of these trade‐offs. Future studies should incorporate newly derived methods that provide reproducible and precise ways to evaluate early life stress, while incorporating populations that are often neglected.     

Discriminability and preference among milking machine functions by dairy cows

An attempt was made to assess discomfort to the cow associated with milking machine function. Seven cows were presented with conditional discrimination tasks between alternative stimuli, using operant conditioning procedures. No discrimination between stimuli was evident. When allowed to choose between wide and narrow pulsation ratios, the 7 cows failed to do more than respond randomly. Four of the cows who were given a choice between potentially more or less aversive stimuli, pulsation vs. zero pulsation, showed no clear preference. The data suggest either that cows cannot discriminate within the experimental range of machine functions, i.e. that no measurable preference existed, or, under the experimental methods used, that cows could not learn the conditional discrimination required.