Nutritional assessment of genetically modified rapeseed synthesizing high amounts of mid-chain fatty acids including production responses of growing-finishing pigs

The nutritive value of genetically modified myristic acid-rich rapeseed, in which a acyl-thioesterase gene inserted, was studied. Crude nutrients, amino acid and fatty acid profiles as well as mineral and glucosinolate contents were determined and compared with those of the non-transgenic parental cultivar. The concentration of crude nutrients, minerals and amino acids were found to be within the range of natural variance. The myristic and palmitic acid content increased from 0.1 - 11.4% and from 3.6-20%, respectively, at the expense of oleic acid, which decreased from 68.6-42.6% of total fatty acids. The glucosinolate contents increased from 12.4 micromol/g in the parental plant to 19 micromol/g DM in the GM-plant. Full-fat rapeseed of both cultivars was incorporated in pig diets at a level of 15%, and the digestibility and the production efficiency were tested under ad libitum feeding conditions with ten pigs each over the growing finishing period from 32-105 kg BW. The experimental diets did not show significant differences in digestibility and energetic feeding value. However, feed intake and weight gain decreased presumably due to the increasing glucosinolate intake associated with the feeding of transgenic rapeseed. The dietary fatty acids profile influenced the fatty acid profile of body fat. Myristic acid accumulated in back fat and intramuscular fat while the oleic acid content decreased. The increased glucosinolate intake affected the weight of thyroid glands and their iodine concentration.     

Methane production in cattle calculated by the nutrient composition of the diet

In this study data originating from complete metabolic trials with cattle of both sexes, fed 337 rations at feed intake levels between one to three times maintenance energy requirement were used to regress the total CH4 emission to the level of DM intake and to the nutrient composition, respectively. A major component of the measured CH4 emission cannot be explained by DM intake but is rather due to differences in dietary nutrient composition. The amount of digestible nutrients especially of the carbohydrate fraction (starch, sugar, N-free residuals) are reliable to estimate CH4 release with high precision (r2 = 0.885). Its production rate increased to 1.9-fold higher levels (range 1.8-2.1) per g of N-free residuals compared to that induced per g of protein, starch or sugar, respectively. Furthermore, diets rich in fat reduced CH4 formation in the rumen. The regression equations fit a wide range of diets and diet compositions, and more importantly, they are applicable to various types of production systems.     

Protein kinase CK2 activates the atypical Rio1p kinase and promotes its cell-cycle phase-dependent degradation in yeast

Using co-immunoprecipitation combined with MS analysis, we identified the alpha' subunit of casein kinase 2 (CK2) as an interaction partner of the atypical Rio1 protein kinase in yeast. Co-purification of Rio1p with CK2 from Deltacka1 or Deltacka2 mutant extracts shows that Rio1p preferentially interacts with Cka2p in vitro. The C-terminal domain of Rio1p is essential and sufficient for this interaction. Six C-terminally located clustered serines were identified as the only CK2 sites present in Rio1p. Replacement of all six serine residues by aspartate, mimicking constitutive phosphorylation, stimulates Rio1p kinase activity about twofold in vitro compared with wild-type or the corresponding (S > A)(6) mutant proteins. Both mutant alleles (S > A)(6) or (S > D)(6) complement in vivo, however, growth of the RIO1 (S > A)(6) mutant is greatly retarded and shows a cell-cycle phenotype, whereas the behaviour of the RIO1 (S > D)(6) mutant is indistinguishable from wild-type. This suggests that phosphorylation by protein kinase CK2 leads to moderate activation of Rio1p in vivo and promotes cell proliferation. Physiological studies indicate that phosphorylation by CK2 renders the Rio1 protein kinase susceptible to proteolytic degradation at the G(1)/S transition in the cell-division cycle, whereas the non-phosphorylated version is resistant.     

Interactions and subcellular distribution of DNA replication initiation proteins in eukaryotic cells

For initiation of eukaryotic DNA replication the origin recognition complex (ORC) associates with chromatin sites and constitutes a landing pad allowing Cdc6, Cdt1 and MCM proteins to accomplish the pre-replication complex (pre-RC). In S phase, the putative MCM helicase is assumed to move away from the ORC to trigger DNA unwinding. By using the fluorescence-based assays bioluminescence resonance energy transfer (BRET) and bimolecular fluorescence complementation (BiFC) we show in live mammalian cells that one key interaction in pre-RC assembly, the interaction between Orc2 and Orc3, is not restricted to the nucleus but also occurs in the cytoplasm. BRET assays also revealed a direct interaction between Orc2 and nuclear localization signal (NLS)-depleted Orc3. Further, we assessed the subcellular distribution of Orc2 and Orc3 in relation to MCM proteins Mcm3 and Mcm6 as well as to a key protein involved in elongation of DNA replication, proliferating nuclear cell antigen (PCNA). Our findings illustrate the spatial complexity of the elaborated process of DNA replication as well as that the BRET and BiFC techniques are novel tools that could contribute to our understanding of the processes at the very beginning of the duplication of the genome.     

Topological reorganization of odor representations in the olfactory bulb

Odors are initially represented in the olfactory bulb (OB) by patterns of sensory input across the array of glomeruli. Although activated glomeruli are often widely distributed, glomeruli responding to stimuli sharing molecular features tend to be loosely clustered and thus establish a fractured chemotopic map. Neuronal circuits in the OB transform glomerular patterns of sensory input into spatiotemporal patterns of output activity and thereby extract information about a stimulus. It is, however, unknown whether the chemotopic spatial organization of glomerular inputs is maintained during these computations. To explore this issue, we measured spatiotemporal patterns of odor-evoked activity across thousands of individual neurons in the zebrafish OB by temporally deconvolved two-photon Ca²⁺ imaging. Mitral cells and interneurons were distinguished by transgenic markers and exhibited different response selectivities. Shortly after response onset, activity patterns exhibited foci of activity associated with certain chemical features throughout all layers. During the subsequent few hundred milliseconds, however, MC activity was locally sparsened within the initial foci in an odor-specific manner. As a consequence, chemotopic maps disappeared and activity patterns became more informative about precise odor identity. Hence, chemotopic maps of glomerular input activity are initially transmitted to OB outputs, but not maintained during pattern processing. Nevertheless, transient chemotopic maps may support neuronal computations by establishing important synaptic interactions within the circuit. These results provide insights into the functional topology of neural activity patterns and its potential role in circuit function.     

Photosynthesis supported by a chlorophyll f-dependent,entropy-driven uphill energy transfer in Halomicronema hongdechloris cells adapted to far-red light

Photosynthesis Research - The phototrophic cyanobacterium Halomicronema hongdechloris shows far-red light-induced accumulation of chlorophyll (Chl) f, but the involvement of the pigment in...     

Physiological studies on cAMP synthesis in Bacillus subtilis

Abstract cAMP was detected in Bacillus subtilis SB 19 and in a temperature sensitive mutant ts 33-6 under oxygen limitation. Growth rate and cAMP content were negatively correlated. Dinitrophenol and α-methylglucoside elicited an increase of the synthesis of cAMP and an increase of the intracellular cAMP content. In response to a decrease was increased. This increase of cAMP concentration did not occur if nitrate was present in the growth medium as an alternative terminal electron acceptor.     

Occurrence of isopropylthio compounds in the aquatic ecosystem (Lake Neusiedl, Austria) as a chemical marker for Microcystis flos-aquae

Abstract Volatile organic sulfur compounds occuring during a bloom of different species of Microcystis in Lake Neusiedl, Austria, were analyzed by gas chromatography and mass spectrometry. In open water diisopropyl disulfide and diisopropyl tri-sulfide were the only sulphur compounds to be found. It was shown that Microcystis flos-aquae was the causative agent for the generation of these sulphur compounds, since high concentrations of these substances were found both in the floating scum of cyanobacteria taken from open lake and in axenic cultures of five isolated strains of M. flos-aquae . Strains isolated from colonies of Microcystis aeruginosa were not able to synthesize isopropylthio compounds. Alternatively, methylthio compounds were released. The rather unusual formation of the isopropylthio group can be used as a chemical marker to differentiate between M. flos-aquae and M. aeruginosa as two separate species which hitherto have been regarded as formae. In a canal passing through the reed belt of Lake Neusiedl where Microcystis was missing, these compounds were not detected. Different sulfur compounds (dimethyl disulfide, dimethyl trisulfide, dibutyl sulfide and bis(methylthio) methane) which in part have not yet been reported for freshwater ecosystems occurred at this site. Their origin, however, remains obscure.