Autoimmunity and increased c-myb transcription

A single recessive gene, lpr, induces an autoimmune-lymphoproliferative syndrome in several strains of mice. The lymphoid organs of lpr/lpr mice contained cells with increased amounts of myb RNA, which codes for a protein found in the nucleus. A similar human lymphoproliferative disorder also had an increase in c-myb expression. Mouse T cells induced by mitogens to proliferate did not express large amounts of myb RNA, indicating that marked myb expression is not a general feature of lymphocyte activation and proliferation.     

Requirement of AMPA receptor GluR2 phosphorylation for cerebellar long-term depression

Cerebellar long-term depression (LTD) is a model of synaptic memory that requires protein kinase C (PKC) activation and is expressed as a reduction in the number of postsynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors. LTD was absent in cultured cerebellar Purkinje cells from mutant mice lacking the AMPA receptor GluR2 subunit and could be rescued by transient transfection with the wild-type GluR2 subunit. Transfection with a point mutant that eliminated PKC phosphorylation of Ser880 in the carboxy-terminal PDZ ligand of GluR2 failed to restore LTD. In contrast, transfection with a point mutant that mimicked phosphorylation at Ser880 occluded subsequent LTD. Thus, PKC phosphorylation of GluR2 Ser880 is a critical event in the induction of cerebellar LTD.     

Diurnal and Semidiurnal Variations in the Earth's Rotation Rate Induced by Oceanic Tides

Recent space-geodetic observations have revealed daily and subdaily variations in the Earth's rotation rate. Although spectral analysis suggests that the variations are primarily of tidal origin, comparisons to previous theoretical predictions based on various ocean models have been less than satisfactory. This disagreement is partly caused by deficiencies in physical modeling. Rotation predictions based on a reliable tidal-height model, with corresponding tidal currents inferred from a modified form of Laplace's momentum equations, yield predictions of tidal variations in Universal Time that agree with very long baseline interferometer observations to 2 microseconds. This agreement resolves a major discrepancy between theory and observation and establishes the dominant role of oceanic tides for inducing variation in the Earth's rotation at these frequencies.     

Fingerprinting methods to approach multitrophic interactions among microflora and microfauna communities in soil

The soil functioning and the response of the biota to external perturbations such as organic input are based on multitrophic interactions among a wide range of organisms. However, the various components of the soil microflora and microfauna are rarely addressed in ecological studies. We have developed a molecular approach based on terminal restriction fragment length polymorphism (T-RFLP) analysis to assess the community structures of protozoa and nematodes, together with bacteria and fungi that share the same soil environment. Two soils were characterized by a specific fingerprint for each of the four groups of organisms, showing the potential of all T-RFLP procedures to differentiate the community structures. The response of the soil biota to organic inputs was addressed using T-RFLP fingerprints together with physiological profiles of bacteria communities and global microbial activities and densities. Although the impact of compost or manure on the soil biota was only slightly noticeable from the global parameters measured, it was obvious from the community level analyses. However, the different components of the soil biota were altered to various extents, depending on the group of organisms and the soil–organic matter combination. The potential of the T-RFLP strategy to analyze simultaneously different biotic groups from the same soil DNA extract will facilitate the more systematic integration of eukaryotic organisms in ecological studies to investigate multitrophic interactions among the microflora and microfauna in relation with soil processes.     

水稻株型育种生理生态特性的研究现状与展望

阐述了株型育种发展的阶段及各阶段的特点,从茎、叶、穗、分蘖、根５个方面与水稻株型育各种有关的各种形态、生理、生态特性的研究现状进行了综合评述。认为株高增加、叶片直立、分蘖力适中、根系发达不早衰是株型育种目标的共同点,而北方粳稻区穗子直立更有利于提高光能利用率。认为通过籼粳稻杂交、水陆稻杂交,并进行多次人回交或复交,将非Ｆ１优势固定或通过籼粳杂交转能广亲和材料采用“架桥”的方法,是实现优化性状组配的     

Disc extrusion in a Rottweiler dog with caudal cervical spondylomyelopathy after failure of intervertebral distraction/stabilisation

A Rottweiler dog was presented with an 8 week history of hindlimb ataxia. Neurological examination localised the lesion to the cervical spinal cord. Myelography demonstrated dynamic compressive lesions at C5-6 and C6-7 consistent with a diagnosis of caudal cervical spondylomyelopathy. Distraction/stabilisation of both discs was performed using interbody polymethyl methacrylate. Both implants subsequently failed leading to extrusion of the remaining dorsal annulus fibrosus of the C5-6 intervertebral disc and nonambulatory tetraparesis. A ventral slot combined with distraction/stabilisation using screws and polymethyl methacrylate was performed and resulted in nearly full neurological recovery.     

MALIGNANT TRANSFORMATION OF SOLITARY SPINAL OSTEOCHONDROMA IN TWO MATURE DOGS

Canine osteochondroma is an uncommon bony tumor that arises in skeletally immature animals. Consequently, clinical signs typically occur in young dogs as a result of impingement of normal structures by the tumor. Radiographically, osteochondromas are benign in appearance. They are well circumscribed and cause no bony lysis nor periosteal proliferation. Osteochondromas may occur in two forms; solitary or multiple. Although histology and biologic behavior are identical, when in the multiple form the condition has been termed multiple cartilaginous exostoses. Malignant transformation of multiple cartilaginous exostoses has been reported in three mature dogs. We report two dogs with malignant transformation of solitary spinal osteochondromas. Both underwent transformation to osteosarcoma. Despite the benign radiographic appearance of osteochondromas and multiple cartilaginous exostoses, clinical signs should alert the clinician to the possibility of malignant transformation.     

Reproductive dominance of pasture trees in a fragmented tropical forest mosaic

Tropical forest fragmentation threatens biodiversity, yet basic information on population responses for major groups such as plants is lacking. Hypervariable genetic markers were used to reconstruct a population-level pedigree in fragmented tropical forest for the tree Symphonia globulifera. Though seedlings occurred only in remnant forest, the pedigree showed that most seedlings had been produced by sequentially fewer adults in pasture, creating a genetic bottleneck. The pedigree also implicated shifts in the foraging of animals that disperse pollen and seed in a secondary constriction of the bottleneck. These results suggest that tropical conservation strategies should anticipate complex, cryptic responses to fragmentation.     

Correction to: Maintenance requirement and utilisation efficiency of energy and protein for ongrowing pikeperch (Sander lucioperca (L.))

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