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.     

Stable oil bodies sheltered by a unique oleosin in lily pollen

Stable oil bodies were purified from mature lily (Lilium longiflorum Thunb.) pollen. The integrity of pollen oil bodies was maintained via electronegative repulsion and steric hindrance possibly provided by their surface proteins. Immunodetection revealed that a major protein of 18 kDa was exclusively present in pollen oil bodies and massively accumulated in late stages of pollen maturation. According to mass spectrometric analyses, this oil body protein possessed a tryptic fragment of 13 residues matching that of a theoretical rice oleosin. A complete cDNA fragment encoding this putative oleosin was obtained by PCR cloning with primers derived from its known 13-residue sequence. Sequence analysis as well as immunological non-cross-reactivity suggests that this pollen oleosin represents a distinct class in comparison with oleosins found in seed oil bodies and tapetum. In pollen cells observed by electron microscopy, oil bodies were presumably surrounded by tubular membrane structures, and encapsulated in the vacuoles after germination. It seems that pollen oil bodies are mobilized via a different route from that of glyoxysomal mobilization of seed oil bodies after germination.     

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.     

Movement of the tube cell in the lily style in the absence of the pollen grain and the spent pollen tube

Our model proposes that pollen tube growth is a form of cell movement where the tube tip can be considered analogous to a migrating cell which leaves a trail of extracellular matrix (the spent pollen tube) behind. We demonstrate that the tube cell can convey the sperm cells to the ovule and effect fertilization even in the absence of the pollen grain and the spent pollen tube. Adhesion is an integral part of cell attachment and movement in animal systems. We show that in vivo-grown pollen tubes grow beneath the cuticle of the stylar transmitting tract epidermis and directly adhere to one another and the outer wall of the epidermal cells. A fibrous wall material is found to cover the tip of the pollen tube cell wall and the surface of the transmitting tract cells where the two adhere. Fixation methods to preserve adhesive compounds were used. The pollen-tubes grown in vivo, but not in vitro, show star-shaped clusters of F-actin microfilaments in the region back from the tip, as seen by rhodamine-phalloidin staining. These configurations are similar to focal adhesions seen in moving animal cells.     

A unique caleosin in oil bodies of lily pollen

In view of the recent isolation of stable oil bodies as well as a unique oleosin from lily pollen, this study examined whether other minor proteins were present in this lipid-storage organelle. Immunological cross-recognition using antibodies against three minor oil-body proteins from sesame suggested that a putative caleosin was specifically detected in the oil-body fraction of pollen extract. A cDNA fragment encoding this putative pollen caleosin, obtained by PCR cloning, was confirmed by immunodetection and MALDI-MS analyses of the recombinant protein over-expressed in Escherichia coli and the native form. Caleosin in lily pollen oil bodies seemed to be a unique isoform distinct from that in lily seed oil bodies.