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The discovery of cyanobacterial phytochrome histidine kinases, together with the evidence that phytochromes from higher plants display protein kinase activity, bind ATP analogs, and possess C-terminal domains similar to bacterial histidine kinases, has fueled the controversial hypothesis that the eukaryotic phytochrome family of photoreceptors are light-regulated enzymes. Here we demonstrate that purified recombinant phytochromes from a higher plant and a green alga exhibit serine/threonine kinase activity similar to that of phytochrome isolated from dark grown seedlings. Phosphorylation of recombinant oat phytochrome is a light- and chromophore-regulated intramolecular process. Based on comparative protein sequence alignments and biochemical cross-talk experiments with the response regulator substrate of the cyanobacterial phytochrome Cph1, we propose that eukaryotic phytochromes are histidine kinase paralogs with serine/threonine specificity whose enzymatic activity diverged from that of a prokaryotic ancestor after duplication of the transmitter module

Salicylic acid-induced protein kinase (SIPK) and wounding-induced protein kinase (WIPK), two distinct members of the mitogen-activated protein (MAP) kinase family, are activated in tobacco resisting infection by tobacco mosaic virus (TMV). WIPK activation by TMV depends on the disease-resistance gene N because infection of susceptible tobacco not carrying the N gene failed to activate WIPK. Activation of WIPK required not only posttranslational phosphorylation but also a preceding rise in its mRNA and de novo synthesis of WIPK protein. The induction by TMV of WIPK mRNA and protein also occurred systemically. Its activation at the mRNA, protein, and enzyme levels was independent of salicylic acid. The regulation of WIPK at multiple levels by an N gene-mediated signal(s) suggests that this MAP kinase may be an important component upstream of salicylic acid in the signal-transduction pathway(s) leading to local and systemic resistance to TMV.

The aim of this study was to examine the physicochemical properties and amino acid composition of rabbit meat after the enrichment of rabbit diet with oregano, sage, and Eleutherococcus senticosus extracts, and to make a comparison with the commercial product XTRACT and control samples. The addition of oregano and sage extracts as well as El. senticosus in the rabbit diet positively influenced the physicochemical properties of rabbit meat by increasing its energy value (P less than 0.05 - sage). Supplementing rabbits feed with oregano and sage extracts led to an improvement of the amino acid composition (P less than 0.01). These findings are also supported by the good health state of rabbits. The diet enriched with the plant extracts is beneficial for the health state of rabbits and the nutritional quality of rabbit meat.

Abscisic acid (ABA) regulation of stomatal aperture is known to involve both Ca2+-dependent and Ca2+-independent signal transduction pathways. Electrophysiological studies suggest that protein phosphorylation is involved in ABA action in guard cells. Using biochemical approaches, we identified an ABA-activated and Ca2+-independent protein kinase (AAPK) from guard cell protoplasts of fava bean. Autophosphorylation of AAPK was rapidly (approx 1 min) activated by ABA in a Ca2+independent manner. ABA-activated autophosphorylation of AAPK occurred on serine but not on tyrosine residues and appeared to be guard cell specific. AAPK phosphorylated histone type III-S on serine and threonine residues, and its activity toward histone type III-S was markedly stimulated in ABA-treated guard cell protoplasts. Our results suggest that AAPK may play an important role in the Ca2+-independent ABA signaling pathways of guard cells

Amino acid composition of the meats of wild and farm pheasants were compared. The following amino acids were determined: Asp, Thr, Ser, Glu, Pro, Gly, Ala, Val, Ile, Leu, Tyr, Phe, His, Lys, Arg. An improved amino acid profile was found in the breast muscle of pheasants kept at the farm in comparison with that of wild pheasants.

Changes in amino acid composition of alfalfa (Medicago sativa L.) phloem sap were studied in response to a water deficit. Sap was collected by stylectomy. As the leaf water potential decreased from -0.4 to -2.0 MPa, there was a significant increase of the total amino acid concentration, due to that of some amino acids: proline, valine, isoleucine, leucine, glutamic acid, aspartic acid, and threonine. Asparagine concentration, which is the main amino acid assayed in the phloem sap of alfalfa (it accounts for 70% of the total content), did not vary with the plant water status. The other amino acid concentrations remained stable as leaf water potential varied; in particular, gamma-amino butyric acid concentration remained unchanged, whereas it varied in response to wounding. The more striking change in the sieve tubes was the accumulation of proline which was observed below a leaf water potential threshold value of about -0.9 MPa (concentration x60 for a decrease of leaf water potential from -0.9 to -2.0 MPa). The role of such changes in phloem sap amino acid concentration in osmotic adjustment of growing tissues is discussed

High performance liquid chromatography (HPLC) method with the pre-column derivatisation by AccQ.Tag agent and following determination of these derivates after their separation in reverse phase column followed by fluorescent detection was used for the determination of amino acids in cheeses. The contents of sixteen free amino acids in twenty five cheeses commercially available in the Czech Republic were measured. The total content of free amino acids in the studied cheeses varied in the range from 27 g/kg to 160 g/kg. Among individual amino acids, seven amino acids were more concentrated in all cheese samples and came from three distinctive taste groups: bitter tasting amino acids (leucine, lysine, and phenylalanine), bitter sweet amino acids (proline and valine), and salty-umami amino acids (glutamic acid and aspartic acid). The differences in the contents of the total and individual free amino acids were influenced by the kind of cheese and mainly by the duration and intensity of proteolysis.

This study examined the ability of late stage (instar XXVI) Japanese spiny lobster Panulirus japonicus phyllosoma larvae to uptake seven L-type amino acids (AAs; aspartic acid, Asp; threonine, Thr; glutamic acid, Glu; glycine, Gly; alanine, Ala; valine, Val; and methionine, Met) from the rearing medium. The time course uptake during incubation for 5 h in solutions containing 1, 2, 5, 10 or 20 microM of each AA was determined using high performance liquid chromatography. There was considerable individual variation in uptake rates and even occasional release of AAs, but larvae showed net uptakes of all seven AAs. Two polar acidic AAs (Glu and Asp) were readily taken up whereas neutral AAs, including three considered as essential for crustaceans (Val, Met, and Thr), had lower uptake rates. Transient releases of AAs by the larvae were common for the AAs with the lowest uptake rates at 1-2 h of incubation. Uptake rates increased with increasing AA concentration but less so for those taken up in larger amounts. Larvae took up AAs to a total of 16.4 micromol/g/h for incubation in the 20 microM solution. The ability to uptake nutrients directly from the medium may be important for the well-being of the larvae.

The relative proportions of free amino acids as well as the amino acid compositions of hydrolysed unprecipitated peptides and hydrolysed whole carcasses were quantified for two aphid species: the gall-dwelling social aphid Pemphigus spyrothecae and the pea aphid Acyrthosiphon pisum. The whole-tissue amino acid profiles of the two taxonomically distant species had a surprisingly high level of correspondence. In contrast, when comparing the A. pisum profiles obtained in the current study to those obtained in an earlier study, major differences were identified. It is concluded that there are good prospects for developing an artificial diet for P. spyrothecae. There may also exist considerable scope for tailoring the existing diets of A. pisum to suit specialised populations which develop poorly on the standard diet. The amino acid profile of P. spyrothecae is the first such profile that has been reported for a gall-forming aphid.