Complexity of transcriptional regulation within the Rag locus: identification of a second Nwc promoter region within the Rag2 intron

Nwc represents a mysterious third evolutionarily conserved gene within the Rag locus. Here, we analyzed the phenotype of Nwctmpro1 mice, in which the Rag2 intragenic region containing the previously identified promoter responsible for initiating transcription of Nwc in all cells except lymphocytes was deleted by homologous recombination. Despite strong nonlymphocyte-specific inhibition of Nwc transcription which runs through the regulatory region of Rag genes, their expression remained suppressed, and no developmental, morphological, anatomical, functional, physiological, or cellular defects in Nwctmpro1 mice could be observed. However, careful analysis of the Rag2 intergenic region uncovered a second evolutionarily conserved Nwc promoter region from which a previously unknown Nwc transcript can be generated in nonlymphocytes of Nwctmpro1 and normal mice. The above results reveal an unexpected additional complexity of transcriptional regulation within the Rag/Nwc locus and show that strong inhibition of Nwc transcription in nonlymphoid cells is well tolerated. Complete inactivation of Nwc is necessary to get insight into its function at transcriptional and posttranscriptional levels

Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings

Wheat (Triticum aestivum L.) seedlings contain four alanine aminotransferase (AlaAT) homologues. Two of them encode AlaAT enzymes, whereas two homologues act as glumate:glyoxylate aminotransferase (GGAT). To address the function of the distinct AlaAT homologues a comparative examination of the changes in transcript level together with the enzyme activity and alanine and glutamate content in wheat seedlings subjected to low oxygen availability, nitrogen and light deficiency has been studied. Shoots of wheat seedlings were more tolerant to hypoxia than the roots as judging on the basis of enzyme activity and transcript level. Hypoxia induced AlaAT1 earlier in roots than in shoots, while AlaAT2 and GGAT were unaffected. The increase in AlaAT activity lagged behind the increase in alanine content. Nitrogen deficiency has little effect on the activity of GGAT. In contrast, lower activity of AlaAT and the level of mRNA for AlaAT1 and AlaAT2 in wheat seedlings growing on a nitrogen-free medium seems to indicate that AlaAT is regulated by the availability of nitrogen. Both AlaAT and GGAT activities were present in etiolated wheat seedlings but their activity was half of that observed in light-grown seedlings. Exposure of etiolated seedlings to light caused an increase in enzyme activities and up-regulated GGAT1. It is proposed that hypoxia-induced AlaAT1 and light-induced peroxisomal GGAT1 appears to be crucial for the regulation of energy availability in plants grown under unfavourable environmental conditions

Properties of selected β-glucan concentrates as potential components of meat products

Celem pracy była ocena wybranych właściwości trzech koncentratów β-glukanu (dwóch z owsa i jednego z jęczmienia). Porównano je z cechami preparatu błonnika pszennego Vitacel® WF-200, stosowanego w polskim przemyśle mięsnym. Oznaczono wodochłonność preparatów przed i po obróbce cieplnej metodą wirówkową oraz oceniono ich barwę (instrumentalnie i sensorycznie). W przypadku koncentratów β-glukanu z owsa i jęczmienia określono również intensywność zapachu zbożowego. Wodochłonność koncentratów z owsa wzrastała po obróbce cieplnej (ponad dwukrotnie) i była wtedy istotnie większa niż wodochłonność koncentratu z jęczmienia i preparatu WF-200. Przed obróbką cieplną zależność ta była odwrotna. Koncentraty z owsa charakteryzowały się większą jasnością (L*) oraz mniejszymi parametrami a* i b* niż koncentrat z jęczmienia. Barwa koncentratów β-glukanu z owsa i jęczmienia była ciemniejsza niż preparatu WF-200. Koncentraty z owsa charakteryzowały się mniejszą intensywnością zapachu zbożowego niż koncentrat z jęczmienia. Właściwości koncentratów z owsa ocenianych jako potencjalne dodatki do przetworów mięsnych były lepsze niż koncentratu z jęczmienia.The aim of this work was to assess selected properties of three β-glucan concentrates from oat and barley. They were compared with characteristics of Vitacel® WF-200 wheat fibre, which is used in Polish meat industry. Water holding capacity (before and after heat treatment, using centrifugal method) and colour (instrumental and sensory) of the preparations were determined. In the case of β-glucan concentrates from oat and barley the intensity of cereal smell was also assessed. Water holding capacity (WHC) of oat β-glucan concentrates increased more than two times after heat treatment and was thereafter significantly higher than the WHC of barley β-glucan concentrate and wheat fibre. This relationship was opposite before heat treatment. The oat β-glucan concentrates were lighter and had lower a* and b* colour values than the concentrate from barley. β-glucan concentrates from oat and barley were darker than WF-200 wheat fibre. Oat β-glucan concentrates displayed less intensive cereal smell than the barley β-glucan concentrate. They had more advantageous characteristics as potential additives to meat products than the concentrate from barley

Phorbol ester-mediated re-expression of endogenous LAT adapter in J.CaM2 cells: a model for dissecting drivers and blockers of LAT transcription.

Linker for activation of T cells (LAT) is a raft-associated, transmembrane adapter protein critical for T-cell development and function. LAT expression is transiently upregulated upon T-cell receptor (TCR) engagement, but molecular mechanisms conveying TCR signaling to enhanced LAT transcription are not fully understood. Here we found that a Jurkat subline J.CaM2, initially characterized as LAT deficient, conditionally re-expressed LAT upon the treatment with a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). We took advantage of the above observation for studying cis-elements and trans-acting factors contributing to the activation-induced expression of LAT. We identified a LAT gene region spanning nucleotide position -14 to +357 relative to the ATG start codon as containing novel cis-regulatory elements that were able to promote PMA-induced reporter transcription in the absence of the core LAT promoter. Interestingly, a point mutation in LAT intron 1, identified in J.CaM2 cells, downmodulated LAT promoter activity by 50%. Mithramycin A, a selective Sp1 DNA-binding inhibitor, abolished LAT expression upon PMA treatment as did calcium ionophore ionomycin (Iono) and valproic acid (VPA), widely used as an anti-epileptic drug. Our data introduce J.CaM2 cells as a model for dissecting drivers and blockers of activation induced expression of LAT

Effect of Gel-fat preparate on the quality of poultry roasts

Badano wpływ dodatku preparatu Gel-fat na wybrane wyróżniki jakości modelowych pieczeni drobiowych. Przygotowano 3 warianty pieczeni, zróżnicowanych pod względem dodatku preparatu Gel-fat i zawartości tłuszczu (wariant I kontrolny – bez dodatku preparatu i zawierający 15% tłuszczu, wariant II – zawierający 1% preparatu oraz 15% tłuszczu oraz wariant III – 1% dodatku preparatu Gel-fat oraz 20% tłuszczu). W pieczeniach oznaczano ubytki termiczne, wyciek tłuszczu oraz podstawowy skład chemiczny, dokonano pomiarów parametrów barwy L*, a*, b* oraz maksymalnej siły penetracji, a także przeprowadzono ocenę sensoryczną. Na podstawie otrzymanych wyników stwierdzono, że produkty zawierające preparat Gel-fat (również z większym udziałem tłuszczu) charakteryzowały się mniejszymi ubytkami termicznymi (średnio o 3 jednostki procentowe), nie wykazano natomiast różnic w ilości wytopionego tłuszczu. Zastosowanie dodatku preparatu Gel-fat nie wpłynęło istotnie na podstawowy skład chemiczny, siłę penetracji, parametry barwy oraz na cechy sensoryczne pieczeni drobiowych. Zwiększenie udziału surowca tłuszczowego w recepturze przyczyniło się do istotnego zmniejszenia wartości siły penetracji, warunkowało również podstawowy skład chemiczny pieczeni (większa zawartość tłuszczu i mniejsza zawartość wody).The effect of Gel-fat preparate on selected model quality of the poultry roasts was investigated in this study. It was prepared 3 variants of poultry roasts, varied in terms of additive Gel-fat preparate and fat raw material (control variant – without Gelfat addition and 15% fat raw material content, II variant – with 1% Gel-fat addition and 15% fat raw material content, III variant – with 1% Gel-fat addition and 20% fat raw material content). In roasts were measured thermal losses, fat leakage and basic chemical composition, color parameters L*, a*, b* and the maximum force of penetration, as well as sensory characteristic. Based on these results it was found that products containing Gel-fat preparate (with higher proportion of fat also) had lower thermal losses (an average of about 3 units), whereas there was no difference in the amount of fat leakage. Additive of Gel-fat preparate did not infl uence signifi cantly on the basic chemical composition, the force of penetration, color parameters and sensory characteristics of roasts poultry. Higher proportion of fat in the formulation resulted in a signifi cant decrease in the force of penetration. It also infl uenced the basic chemical composition of roasts (higher fat content and lower water content)

Effect of oat fibre Vitacel HF 600 on quality of beef-pork burgers

Celem pracy było zbadanie wpływu dodatku preparatu błonnika owsianego Vitacel® HF 600 na fizyczne, chemiczne i sensoryczne wyróżniki jakości hamburgerów wołowo-wieprzowych o stałym składzie surowcowym (85% mięso wołowe kl. II, 15% podgardle wieprzowe). Przygotowano cztery warianty produktów: kontrolny (niezawierający błonnika owsianego) oraz z dodatkiem 1,5, 3,0 i 6,0% preparatu błonnikowego. Jakość hamburgerów poddanych pieczeniu w piecu konwekcyjno-parowym oceniano po 24 h przechowywania w warunkach chłodniczych. Stwierdzono, że wprowadzenie do składu recepturowego hamburgerów błonnika owsianego nie miało istotnego wpływu na podstawowy skład chemiczny i siłę cięcia, ale różnicowało istotnie parametry barwy powierzchni produktów. Zastosowanie dodatku preparatu Vitacel® HF 600 do hamburgerów nie spowodowało pogorszenia pożądalności wyróżników sensorycznych poddanych ocenie. Istotne różnice między produktami stwierdzono jedynie w ocenie twardości. Biorąc pod uwagę uzyskane wyniki, wnioskowano, że ilość dodatku preparatu Vitacel® HF 600 do farszu na hamburgery o przyjętym składzie recepturowym nie powinna być większa niż 3,0%.The aim of the study was to evaluate the effect of oat fibre preparation Vitacel® HF 600 on selected quality characteristics of beef-pork hamburgers with a consistent raw material composition (85% beef trimmings class II, 15% pork jowl without skin). Products of four formulations were prepared: control (without addition of the oat fibre preparation), and containing: 1.5, 3.0 and 6.0% of the oat fibre preparation (in relation to the weight of the raw meat and water). Evaluation of the quality of hamburgers included determination of the yield of product by the weighing method, the content of water, protein and fat by the near-infrared (NIR) spectrometry method, the content of salt by the potentiometric method, measurement of water activity, instrumental measurement of colour parameters L*a*b*, texture (shear force) and sensory assessment of colour, odour, taste, hardness, juiciness and overall sensory acceptability of products. The evaluation of quality characteristics of hamburgers was carried out for four production batches in products subjected to heat treatment. It was found that the addition of 6.0% of oat fibre preparation into the batter for hamburgers resulted in significant decrease of the yield and water activity of products, as compared to the control product. The oat fibre preparation had no significant effect on the basic chemical composition and shear force of hamburgers but differentiated the colour of the surface of products. Based on the results of sensory evaluation of hamburgers containing the Vitacel® HF 600 preparation no significantly negative effect of this functional additive on appearance and colour, odour, taste, juiciness and overall acceptability of products was found. However, product containing 1.5% of the oat fibre preparation characterized by a significantly more desirable hardness than the product containing 6.0% of this preparation. Correlation analysis showed a statistically significant, relatively strong correlation between sensory evaluation of colour and the value of redness (a*), between sensory evaluation of juiciness and fat content in hamburgers. Taking into account the production yield, the results of instrumental colour measurements and sensory evaluation of hardness, it may be concluded that the addition level of Vitacel® HF 600 preparation into the batter for beef-pork hamburgers of adopted raw material composition should not exceed 3.0%