Pre-historic cucurbits from the Valley of Oaxaca

About 180 specimens of cucurbits were recovered from the Guila Naquitz Cave in the Valley of Oaxaca, Mexico, from strata dated at 8750-7840 B.C. to 1500 A.D. by Carbon- 14 analyses. 4 Almost 60% of the cucurbit specimens were of wild species of Cucurbita. A single seed may be that of the perennial squash or fig- leaf gourd, C. ficifolia Bouch é. All other cultivated squash material was C. pepo L., the summer squash. Cucurbita pepo prefers cool, dry environmental conditions. This suggests that farmers utilized the cave on a seasonal basis, because cultivars of C. pepo mature later and store better than those of C. moschata Poir. or C. mixta Pang., which would normally be the species expected to be cultivated at this latitude. Specimens of bottle gourd, Lagenaria siceraria (Mol.) Standl., were comparatively rare and comprised only 10% of the total. The scarcity of bottle gourd remains suggests that these gourds were not important for containers and household, use even in preceramic levels, or that they simply did not break many of their vessels during the limited time they occupied the cave. A second possibility is that agriculture was carried out at higher and cooler elevations, which C. pepo prefers but which are unfavorable for Lagenaria. A few Apodanthera seeds were found at all levels.     

ACCELERATED EFFLUX OF [14C] AND [3H] AMINO ACIDS FROM SUPERFUSED SLICES OF RAT BRAIN1

Abstract— The rate of spontaneous efflux of several isotopically-labelled amino acids was measured in superfused slices of rat brain. The group specificity of amino acid efflux was studied by examining the pattern of accelerated efflux in the presence of extracellular unlabeled amino acid. The mediated efflux of γ-aminobutyric acid and l -glutamic acid was highly specific. Less specificity was found for amino acids in the small neutral, large neutral and basic groups. The efflux of γ-aminobutyric acid and l -glutamic acid was accelerated by structurally similar amino acids which are known to depress or excite motor neurons. This finding raises the possibility that the physiological effects of non-specific amino acids during local iontophoresis may be secondary to an accelerated release of more specific transmitter amino acids from neighbouring cells.     

Secretagogue-triggered Transfer of Membrane Proteins from Neuroendocrine Secretory Granules to Synaptic-like Microvesicles

The membrane proteins of all regulated secretory organelles (RSOs) recycle after exocytosis. However, the recycling of those membrane proteins that are targeted to both dense core granules (DCGs) and synaptic-like microvesicles (SLMVs) has not been addressed. Since neuroendocrine cells contain both RSOs, and the recycling routes that lead to either organelle overlap, transfer between the two pools of membrane proteins could occur during recycling. We have previously demonstrated that a chimeric protein containing the cytosolic and transmembrane domains of P-selectin coupled to horseradish peroxidase is targeted to both the DCG and the SLMV in PC12 cells. Using this chimera, we have characterized secretagogue-induced traffic in PC12 cells. After stimulation, this chimeric protein traffics from DCGs to the cell surface, internalizes into transferrin receptor (TFnR)-positive endosomes and thence to a population of secretagogue-responsive SLMVs. We therefore find a secretagogue-dependent rise in levels of HRP within SLMVs. In addition, the levels within SLMVs of the endogenous membrane protein, synaptotagmin, as well as a green fluorescent protein-tagged version of vesicle-associated membrane protein (VAMP)/synaptobrevin, also show a secretagogue-dependent increase.     

The abundance of an invasive freshwater snail Tarebia granifera (Lamarck, 1822) in the Nseleni River,South Africa

The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.     

Effect of Interdomain Linker Length on an Antagonistic Folding-Unfolding Equilibrium between Two Protein Domains

Fusion of one protein domain with another is a common event in both evolution and protein engineering experiments. When insertion is at an internal site (e.g., a surface loop or turn), as opposed to one of the termini, conformational strain can be introduced into both domains. Strain is manifested by an antagonistic folding-unfolding equilibrium between the two domains, which we previously showed can be parameterized by a coupling free-energy term (ΔG_X). The extent of strain is predicted to depend primarily on the ratio of the N-to-C distance of the guest protein to the distance between ends of the surface loop in the host protein. Here, we test that hypothesis by inserting ubiquitin (Ub) into the bacterial ribonuclease barnase (Bn), using peptide linkers from zero to 10 amino acids each. ΔG_X values are determined by measuring the extent to which Co²⁺ binding to an engineered site on the Ub domain destabilizes the Bn domain. All-atom, unforced Langevin dynamics simulations are employed to gain structural insight into the mechanism of mechanically induced unfolding. Experimental and computational results find that the two domains are structurally and energetically uncoupled when linkers are long and that ΔG_X increases with decreasing linker length. When the linkers are fewer than two amino acids, strain is so great that one domain unfolds the other. However, the protein is able to refold as dimers and higher-order oligomers. The likely mechanism is a three-dimensional domain swap of the Bn domain, which relieves conformational strain. The simulations suggest that an effective route to mechanical unfolding begins with disruption of the hydrophobic core of Bn near the Ub insertion site.     

5-(1H-Benzimidazol-1-yl)-3-alkoxy-2-thiophenecarbonitriles as potent, selective, inhibitors of IKK-epsilon kinase

The identification and hit-to-lead exploration of a novel, potent and selective series of substituted benzimidazole–thiophene carbonitrile inhibitors of IKK-ε kinase is described. Compound 12e was identified with an IKK-ε enzyme potency of pIC₅₀ 7.4, and has a highly encouraging wider selectivity profile, including selectivity within the IKK kinase family.     

The contribution of adhesion signaling to lactogenesis

The mammary gland undergoes hormonally controlled cycles of pubertal maturation, pregnancy, lactation, and involution, and these processes rely on complex signaling mechanisms, many of which are controlled by cell–cell and cell–matrix adhesion. The adhesion of epithelial cells to the extracellular matrix initiates signaling mechanisms that have an impact on cell proliferation, survival, and differentiation throughout lactation. The control of integrin expression on the mammary epithelial cells, the composition of the extracellular matrix and the presence of secreted matricellular proteins all contribute to essential adhesion signaling during lactogenesis. In vitro and in vivo studies, including the results from genetically engineered mice, have shed light on the regulation of these processes at the cell and tissue level and have led to increased understanding of the essential signaling components that are regulated in temporal and cell specific manner during lactogenesis. Recent studies suggest that a secreted matricellular protein, CTGF/CCN2, may play a role in lactogenic differentiation through binding to β1 integrin complexes, enhancing the production of extracellular matrix components and contributions to cell adhesion signaling.     

Empirical Evaluation of Oligonucleotide Probe Selection for DNA Microarrays

DNA-based microarrays are increasingly central to biomedical research. Selecting oligonucleotide sequences that will behave consistently across experiments is essential to the design, production and performance of DNA microarrays. Here our aim was to improve on probe design parameters by empirically and systematically evaluating probe performance in a multivariate context. We used experimental data from 19 array CGH hybridizations to assess the probe performance of 385,474 probes tiled in the Duchenne muscular dystrophy (DMD) region of the X chromosome. Our results demonstrate that probe melting temperature, single nucleotide polymorphisms (SNPs), and homocytosine motifs all have a strong effect on probe behavior. These findings, when incorporated into future microarray probe selection algorithms, may improve microarray performance for a wide variety of applications.