The suitability of a faecal suspension of sheep as inocula for the estimation of utilizable crude protein of feeds by in vitro incubation

The objective of this review is to outline those parts of modelling approaches in pig production which are not highly developed; these are the partitioning of protein and lipid accretion in different anatomical body parts. The authors introduce present models with a critical evaluation and draw some conlusions for further developments. Based on present knowledge this paper demonstrates the process of protein and fat accretion in different body compartments in pigs and influencing factors. A further aim is to assist in the conceptual development of a new pig model, which is more detailed, precise and accurate than currently available models. Exsisting models are generally deficient with regard to the translation of lipid and protein gain into lean and fatty tissue. Only assumed values for this translation have been used so far and the concepts underlying these values are not well understood. Therefore, it may be appropriate to develop a compartimental model to predict protein and fat deposition in growing and fattening pigs. With this new approach the model can supply sufficiently the changing consumer demands regarding to the possibility of meat quality prediction.     

Soil inorganic carbon storage pattern in China

Soils with pedogenic carbonate cover about 30% (3.44 × 10⁶ km²) of China, mainly across its arid and semiarid regions in the Northwest. Based on the second national soil survey (1979–1992), total soil inorganic carbon (SIC) storage in China was estimated to be 53.3±6.3 PgC (1 Pg=10¹⁵ g) to the depth investigated to 2 m. Soil inorganic carbon storages were 4.6, 10.6, 11.1, and 20.8 Pg for the depth ranges of 0–0.1, 0.1–0.3, 0.3–0.5, and 0.5–1 m, respectively. Stocks for 0.1, 0.3, 0.5, and 1 m of depth accounted for 8.7%, 28.7%, 49.6%, and 88.9% of total SIC, respectively. In contrast with soil organic carbon (SOC) storage, which is highest under 500–800 mm yr⁻¹ of mean precipitation, SIC storage peaks where mean precipitation is <400 mm yr⁻¹. The amount and vertical distribution of SIC was related to climate and land cover type. Content of SIC in each incremental horizon was positively related with mean annual temperature and negatively related with mean annual precipitation, with the magnitude of SIC content across land cover types showing the following order: desert, grassland >shrubland, cropland >marsh, forest, meadow. Densities of SIC increased generally with depth in all ecosystem types with the exception of deserts and marshes where it peaked in intermediate layers (0.1–0.3 m for first and 0.3–0.5 m for latter). Being an abundant component of soil carbon stocks in China, SIC dynamics and the process involved in its accumulation or loss from soils require a better understanding.     

Concordant phylogeography and cryptic speciation in two Western Palaearctic oak gall parasitoid species complexes

Little is known about the evolutionary history of most complex multi‐trophic insect communities. Widespread species from different trophic levels might evolve in parallel, showing similar spatial patterns and either congruent temporal patterns (Contemporary Host‐tracking) or later divergence in higher trophic levels (Delayed Host‐tracking). Alternatively, host shifts by natural enemies among communities centred on different host resources could disrupt any common community phylogeographic pattern. We examined these alternative models using two Megastigmus parasitoid morphospecies associated with oak cynipid galls sampled throughout their Western Palaearctic distributions. Based on existing host cynipid data, a parallel evolution model predicts that eastern regions of the Western Palaearctic should contain ancestral populations with range expansions across Europe about 1.6 million years ago and deeper species‐level divergence at both 8–9 and 4–5 million years ago. Sequence data from mitochondrial cytochrome b and multiple nuclear genes showed similar phylogenetic patterns and revealed cryptic genetic species within both morphospecies, indicating greater diversity in these communities than previously thought. Phylogeographic divergence was apparent in most cryptic species between relatively stable, diverse, putatively ancestral populations in Asia Minor and the Middle East, and genetically depauperate, rapidly expanding populations in Europe, paralleling patterns in host gallwasp species. Mitochondrial and nuclear data also suggested that Europe may have been colonized multiple times from eastern source populations since the late Miocene. Temporal patterns of lineage divergence were congruent within and across trophic levels, supporting the Contemporary Host‐tracking Hypothesis for community evolution.     

Cadmium exerts its toxic effects on photosynthesis via a cascade mechanism in the cyanobacterium,Synechocystis PCC 6803

Despite intense research, the mechanism of Cd²⁺ toxicity on photosynthesis is still elusive because of the multiplicity of the inhibitory effects and different barriers in plants. The quick Cd²⁺ uptake in Synechocystis PCC 6803 permits the direct interaction of cadmium with the photosynthetic machinery and allows the distinction between primary and secondary effects. We show that the CO₂‐dependent electron transport is rapidly inhibited upon exposing the cells to 40 µm Cd²⁺ (50% inhibition in ～15 min). However, during this time we observe only symptoms of photosystem I acceptor side limitation and a build of an excitation pressure on the reaction centres, as indicated by light‐induced P700 redox transients, O₂ polarography and changes in chlorophyll a fluorescence parameters. Inhibitory effects on photosystem II electron transport and the degradation of the reaction centre protein D1 can only be observed after several hours, and only in the light, as revealed by chlorophyll a fluorescence transients, thermoluminescence and immunoblotting. Despite the marked differences in the manifestations of these short‐ and long‐term effects, they exhibit virtually the same Cd²⁺ concentration dependence. These data strongly suggest a cascade mechanism of the toxic effect, with a primary effect in the dark reactions.     

Photo-induced crosslinking of histones H3 and H1 to DNA in deoxyribonucleoprotein: implication in studying histone-DNA interactions.

A thymine-modified derivative of histone H3, isolated as a result of heat treatment of covalently crosslinked DNA-protein photoadduct from UV-irradiated chromatin, was obtained. Sequence analysis of one of its tryptic peptides revealed that lysine-14 of the N-terminal tail of the histone H3 molecule covalently binds to thymine residue of DNA. This type of UV-crosslinking is most probably the only type for histone H3 and, possibly, for H1.     

Influence of chromatin structure, antibiotics, and endogenous histone methylation on phosphorylation of histones H1 and H3 in the presence of protein kinase A in rat liver nuclei in vitro

In vitro phosphorylation of histones H1 and H3 by cAMP-dependent protein kinase A and endogenous phosphokinases in the presence of [γ-³²P]ATP was studied in isolated rat liver nuclei with different variants of chromatin structural organization: condensed (diameter of fibrils 100–200 nm; N-1) and partly decondensed (diameter of fibrils ～30 nm; N-2). In the N-1 state histone, H1 is phosphorylated approximately twice as much than histone H3. Upon the decondensation of the chromatin in the N-2 state, 1.5-fold decrease of total phosphorylation of H1 is observed, while that of H3 does not change, although the endogenous phosphorylation of both histones is reduced by half. Changes in histone phosphorylation in the presence of low or high concentrations of distamycin and chromomycin differ for H1 and H3 in N-1 and N-2. It was found that distamycin (DM) stimulates the phosphorylation of tightly bound H1 fraction, which is not extractable by polyglutamic acid (PG), especially in N-1. Chromomycin (CM) increases the phosphorylation of both histones in PG extracts and in the nuclear pellets, particularly in N-2. At the same time, in N-1 one can detect phosphorylation of a tightly bound fraction of histones H1 whose N-termini are located on AT-rich sites that become inaccessible for protein kinase in the process of chromatin decondensation in N-2. At the same time, in N-2 the accessibility for protein kinase A of tightly bound H1 fractions, whose N-termini are located on GC-rich sites, increases dramatically. High concentrations of both CM and DM in N-1 and N-2 stimulated phosphorylation of the non-extractable by PG fraction of H1 whose N-termini are located on sites where AT ≈ GC. CM at high concentration stimulated 4–7 times the phosphorylation of a small fraction of H3, which is extracted by PG from both types of nuclei. We detected an effect of endogenous methylation of histones H1 and H3 in the nuclei on their subsequent phosphorylation depending on the chromatin structure, histone-chromatin binding strength, and concentration of DM.     

Oligopeptidase B from <Emphasis Type="Italic">Serratia proteamaculans</Emphasis>. III. Inhibition analysis. Specific interactions with metalloproteinase inhibitors

Inhibition of the novel oligopeptidase B from Serratia proteamaculans (PSP) by basic pancreatic trypsin inhibitor, Zn²⁺ ions, and o- and m-phenanthroline was investigated. A pronounced effect of calcium ions on the interaction of PSP with inhibitors was demonstrated. Inversion voltamperometry and atomic absorption spectrometry revealed no zinc ions in the PSP molecule. Hydrophobic nature of the enzyme inhibition by o- and m-phenanthroline was established.     

H1 Histone in Developing and Aging Coleoptiles of Etiolated Wheat Seedlings

It has been established that the DNA and H1 histone contents in aged coleoptile of 8-day-old etiolated wheat seedling are about 40 and 30%, respectively, lower than those in young seedlings. H1 histone in wheat seedlings is represented as six electrophoretically different subfractions. The ratios of H1 histone subfractions in wheat coleoptile and initial leaf are similar. In contrast to some animal cells, apoptosis in wheat coleoptile is not accompanied by changes in the set and ratios of H1 histone subfractions. Aging of coleoptiles is associated with a progressive diminution of the H1 histone and DNA contents. H1 histone/DNA ratio in aged coleoptile is 1.5-2-fold higher than that in the young organs. Therefore, the content of H1 histone in chromatin of coleoptile decreases with age more slowly than DNA content.