Adrenal chromaffin granules and secretory granules from thyroid parafollicular cells have several common antigens

The presence of various antigens in two types of isolated endocrine vesicles (chromaffin granules and secretory vesicles of thyroid parafollicular cells) was investigated by immunoblotting. The two types of vesicles have three common secretory proteins: chromogranin A, chromogranin B and secretogranin II. Furthermore, six common membrane antigens were found: cytochrome b-561, carboxypeptidase H, glycoprotein II, glycoprotein III, synaptin/synaptophysin and SV 2. These results demonstrate that vesicles obtained from neural crest-derived endocrine cells not only share several common secretory peptides and proteins, but also have common properties as far as their membrane antigens are concerned.     

Oxidation of methyl derivatives of pteridin-4-one, lumazine and related pteridines by bovine milk xanthine oxidase.

1. Pteridin-4-ones, methylated at nitrogen or carbon, N-methylated lumazines and related oxopteridines were studied as substrates of a highly purified bovine milk xanthine oxidase (xanthine : oxygen oxidoreductase, EC 1.2.3.2). 2. The enzyme can oxidise at high rates both uncharged and anionic substrates. Variation of enzymic activity with pH is mainly due to pH-dependent changes in the active enzymic center. 3. Milk xanthine oxidases at different stages of purification convert pteridin-4-one into the 4,7-dione (compound 13 in this article). 4. Methylation at C-6 in the pyrazine moiety enhances enzymic attack at C-2 in the pyrimidine ring. N-Methylation may increase or reduce rates of oxidation. 5. For oxidation at C-2, the most favorable form of the substrate bears a double bond at C(2) = N(3). Attack at C-7 is enhanced strongly in structures bearing a double bond at C(6) = C(7). 6. In general, pteridines react with xanthine oxidase as non-hydrated molecules. However, oxidation of 8-methyllumazine at C-7 may take place by dehydrogenation of the 7-CHOH group of the covalently hydrated molecule.     

Peptic ulcers and erosions are common in Israeli children undergoing upper endoscopy

Background: Peptic ulcers and erosions (PU&E) are thought to be uncommon in children. Patients with early exposure to Helicobacter pylori may be at a higher risk for early onset PU&E. Children in Israel have a high prevalence and early acquisition of Helicobacter pylori (H. pylori) and have easy access to pediatric gastroenterologists and endoscopy. Our aim was to describe the prevalence and characteristics of PU&E in this population referred by Pediatric Gastroenterologists for an upper endoscopy. Methods: We conducted a retrospective study over the years January 2003–May 2006. Over these years we had information on 751 diagnostic upper endoscopies. PU&E was regarded as erosive gastritis/duodenitis or ulcer in either the stomach or duodenum. H. pylori status was assessed using rapid urease test and gastric biopsies. Results: PU&E was detected in 169 (22.5%) patients (ulcers 51 (6.8%), erosions 118 (15.7%)). One hundred twenty‐four had gastric PU&E and 58 had duodenal PU&E. H. pylori was positive in 112 (66.3%). H. pylori‐associated PU&E becomes common after age 10 years, with gastric PU&E presenting much earlier than duodenal disease. Most of the H. pylori‐negative PU&E were idiopathic and improved symptomatically on PPI treatment. Interestingly, 43% of patients with PU&E in our cohort were either immigrants from the former Soviet Union or of Israeli Arab origin. Conclusions: PU&E appears to be common in this selected population with a relatively high incidence of gastric PU&E. H. pylori associated PU&E becomes common after age 10 years with gastric PU&E presenting much earlier than duodenal disease. Non H. pylori PU&E in children comprises approximately a third of all PU&E, are mostly idiopathic and appear earlier than H. pylori associated PU&E.     

Translation efficiency in humans: tissue specificity,global optimization and differences between developmental stages

Various studies in unicellular and multicellular organisms have shown that codon bias plays a significant role in translation efficiency (TE) by co-adaptation to the tRNA pool. Yet, in humans and other mammals the role of codon bias is still an open question, with contradictory results from different studies. Here we address this question, performing a large-scale tissue-specific analysis of TE in humans, using the tRNA Adaptation Index (tAI) as a direct measure for TE. We find tAI to significantly correlate with expression levels both in tissue-specific and in global expression measures, testifying to the TE of human tissues. Interestingly, we find significantly higher correlations in adult tissues as opposed to fetal tissues, suggesting that the tRNA pool is more adjusted to the adult period. Optimization based analysis suggests that the tRNA pool—codon bias co-adaptation is globally (and not tissue-specific) driven. Additionally, we find that tAI correlates with several measures related to the protein functionally importance, including gene essentiality. Using inferred tissue-specific tRNA pools lead to similar results and shows that tissue-specific genes are more adapted to their tRNA pool than other genes and that related sets of functional gene groups are translated efficiently in each tissue. Similar results are obtained for other mammals. Taken together, these results demonstrate the role of codon bias in TE in humans, and pave the way for future studies of tissue-specific TE in multicellular organisms.     

Arab football in Israel as an 'integrative enclave'

Over the last two decades, football (soccer) has become a major institution within the popular culture of the Arab-Palestinian citizens of Israel. The centrality of football has given different identity agents opportunities to impose different meanings on the sport, depending on the agents' definitions of collective identity. This article utilizes ethnographic observation in the football stadium and coverage by Arab and Hebrew sports media to illustrate and analyse this battle over meaning. The Hebrew sports media, the Arab sports press, and the Arab audience are three different agents that attach divergent meanings to the notable presence of Arab players in the Israeli football leagues. The article argues that the overlapping interests of the Hebrew sports media on the one hand and the Arab football fans, players, and bureaucrats on the other lead to the construction of the football sphere as an integrative enclave in the general Israeli public sphere. The article considers the relevance of Gramsci's theory of hegemony to explain the production of the integrative meaning of football, and it suggests integrating this explanation with other recent theories regarding the tensions between different discourses of citizenship.     

Association between tree-ring and needle δ<Superscript>13</Superscript>C and leaf gas exchange in <Emphasis Type="Italic">Pinus halepensis</Emphasis> under semi-arid conditions

Associations between δ¹³C values and leaf gas exchanges and tree-ring or needle growth, used in ecophysiological compositions, can be complex depending on the relative timing of CO₂ uptake and subsequent redistribution and allocation of carbon to needle and stem components. For palaeoenvironmental and dendroecological studies it is often interpreted in terms of a simple model of δ¹³C fractionation in C₃ plants. However, in spite of potential complicating factors, few studies have actually examined these relationships in mature trees over inter- and intra-annual time-scales. Here, we present results from a 4 years study that investigated the links between variations in leaf gas-exchange properties, growth, and dated δ¹³C values along the needles and across tree rings of Aleppo pine trees growing in a semi-arid region under natural conditions or with supplemental summer irrigation. Sub-sections of tissue across annual rings and along needles, for which time of formation was resolved from growth rate analyses, showed rapid growth and δ¹³C responses to changing environmental conditions. Seasonal cycles of growth and δ¹³C (up to ~4‰) significantly correlated (P<0.01) with photosynthetically active radiation, vapour pressure deficit, air temperature, and soil water content. The irrigation significantly increased leaf net assimilation, stomatal conductance and needle and tree-ring growth rate, and markedly decreased needle and tree-ring δ¹³C values and its sensitivity to environmental parameters. The δ¹³C estimates derived from gas-exchange parameters, and weighted by assimilation, compared closely with seasonal and inter-annual δ¹³C values of needle- and tree-ring tissue. Higher stomatal conductances of the irrigated trees (0.22 vs. 0.08 mol m⁻² s⁻¹ on average) corresponded with ~2.0‰ lower average δ¹³C values, both measured and derived. Derived and measured δ¹³C values also indicated that needle growth, which occurs throughout the stressful summer was supported by carbon from concurrent, low rate assimilation. For Aleppo pine under semi-arid and irrigated conditions, the δ¹³C of tree-ring and needle material proved, in general, to be a reasonable indicator of integrated leaf gas-exchange properties.     

Evaluation of intrauterine antibiotic treatment of clinical metritis and retained fetal membranes in dairy cows

Retained fetal membranes (RFM) and clinical metritis (CM) are frequently diagnosed disease conditions in dairy cows and considered of major economic impact due to negative effect on reproduction and milk production. The objective of this study was to evaluate the efficacy of i.u. tetracycline for the treatment of RFM and CM in dairy cows. Affected cows were randomly assigned to two groups; treatment group animals received i.u. 5g chlortetracycline twice weekly for 2 wks, and no treatment group. A total of 1416 cows and 804 heifers in 5 herds calved during the study period. CM was diagnosed in 18.6% (inter farm range; 15.2-23.5%) and 30% (19.4-42.3%) of cows and heifers, respectively. RFM was diagnosed in 13.1% (9.4-18.1%) and 9.2% (3.6-13.8%) of cows and heifers, respectively. Conception rates after first insemination were 38.3%, 42.5% and 18% in normal, treated and non-treated CM cows, respectively. Numbers of days open were 140.5, 136.2 and 165.5 in normal, treated and non-treated CM cows, respectively. Based on 305-d corrected milk yield, cows and heifers affected by RFM and CM produced 300-500kg less milk compared with their normal herd mates. Cows treated for CM produced 654kg more milk per 305-d corrected lactation compared to non-treated control cows. Treatment of RFM had no effect on reproductive performance or milk production. In conclusion, i.u. chlortetracycline treatment was proven to prevent the detrimental effect of CM on reproductive performance in heifers and cows and on milk production in cows only.     

ATP-dependent uptake of 5-hydroxytryptamine by secretory granules isolated from thyroid parafollicular cells.

The current study was done to test the hypotheses that parafollicular granules contain a vacuolar ATPase (V-ATPase) similar to that found in chromaffin granules, that the transport of H+ into granules mediated by this enzyme drives the granular uptake of 5-hydroxytryptamine (5-HT, serotonin), and that secretagogues stimulate both the acidification of parafollicular granules and their ability to take up 5-HT by opening an anion channel in the granular membrane. Our studies indicate that parafollicular granules contain a V-ATPase that is antigenically similar to that of the V-ATPase of adrenal chromaffin granules; however, the parafollicular granular membrane differs from that of chromaffin granules in permeability to Cl- and K+. The membranes of granules derived from resting parafollicular cells appear to be relatively impermeable to Cl- but permeable to K+. Parafollicular granules (and ghosts derived from them) manifest ATP-dependent transmembrane transport of 5-HT. This transport is more dependent on the pH difference (delta pH) than on the membrane potential component of the proton electrochemical gradient across the granular membrane. Transport of 5-HT is thus inhibited more by exposure of parafollicular granules to agents, such as nigericin, that collapse delta pH than by those, such as valinomycin, that decrease transmembrane difference in potential. ATP-dependent uptake of 5-HT by granules isolated from secretagogue-stimulated parafollicular cells is greater than that into granules isolated from unstimulated cells. Since secretagogues open a Cl- channel in parafollicular granule membranes, which enhances acidification of the granules, the facilitation of 5-HT uptake by secretagogues is probably due to an increase in delta pH.     

The influence of lipids on voltage-gated ion channels

Voltage-gated ion channels are responsible for transmitting electrochemical signals in both excitable and non-excitable cells. Structural studies of voltage-gated potassium and sodium channels by X-ray crystallography have revealed atomic details on their voltage-sensor domains (VSDs) and pore domains, and were put in context of disparate mechanistic views on the voltage-driven conformational changes in these proteins. Functional investigation of voltage-gated channels in membranes, however, showcased a mechanism of lipid-dependent gating for voltage-gated channels, suggesting that the lipids play an indispensible and critical role in the proper gating of many of these channels. Structure determination of membrane-embedded voltage-gated ion channels appears to be the next frontier in fully addressing the mechanism by which the VSDs control channel opening. Currently electron crystallography is the only structural biology method in which a membrane protein of interest is crystallized within a complete lipid-bilayer mimicking the native environment of a biological membrane. At a sufficiently high resolution, an electron crystallographic structure could reveal lipids, the channel and their mutual interactions at the atomic level. Electron crystallography is therefore a promising avenue toward understanding how lipids modulate channel activation through close association with the VSDs.     

Separation of dissociated thyroid follicular and parfollicular cells: association of serotonin binding protein with parafollicular cells

Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported.