Structure-function relationship of human spinal ligaments

A combination of light, scanning and transmission electron microscopy was used to investigate the morphology and ultrastructure of normal human spinal ligaments sampled from adult surgical specimens. The ligamenta flava consist mostly of dense elastic fibers, whereas the supraspinous and interspinous ligaments are preponderantly collagenous. In all ligaments, the collagen fascicles are characterized by a regular crimp structure. The inner collagen fibers of interspinous ligaments tend to be oriented parallel to the spinous processes while those of the peripheral layers run in postero-cranial direction. The presence of proteoglycan filaments is clearly demonstrated in all of the ligaments examined. They are mainly located at the d band of the collagen fibrils. These findings are discussed in relation to the function of the posterior ligamentous system. It is suggested that the interspinous ligaments are able to transmit tension from the thoracolumbar fascia to the spine. Finally, the spinal ligaments are thought to be involved in the control mechanism of the spine.     

Myeloperoxidase-catalyzed inactivation of alpha 1-protease inhibitor by human neutrophils

We have examined the effect of the myeloperoxidase-hydrogen peroxide-halide system and of activated human neutrophils on the ability of serum alpha 1-protease inhibitor (alpha 1-PI) to bind and inhibit porcine pancreatic elastase. Exposure to the isolated myeloperoxidase system resulted in nearly complete inactivation of alpha 1-PI. Inactivation was rapid (10 to 20 s); required active myeloperoxidase, micromolar concentrations of H2O2 (or glucose oxidase as a peroxide generator), and a halide cofactor (Cl- or I-); and was blocked by azide, cyanide, and catalase. Intact neutrophils similarly inactivated alpha 1-PI over the course of 5 to 10 min. Inactivation required the neutrophils, a halide (Cl-), and a phorbol ester to activate secretory and metabolic activity. It was inhibited by azide, cyanide, and catalase, but not by superoxide dismutase. Neutrophils with absent myeloperoxidase or impaired oxidative metabolism (chronic granulomatous disease) failed to inactivate alpha 1-PI, and these defects were specifically corrected by the addition of myeloperoxidase or H2O2, respectively. Thus, stimulated neutrophils secrete myeloperoxidase and H2O2 which combine with a halide to inactivate alpha 1-PI. We suggest that leukocyte-derived oxidants, especially the myeloperoxidase system, may contribute to proteolytic tissue injury, for example in elastase-induced pulmonary emphysema, by oxidative inactivation of protective antiproteases.     

Intake and digestibility in sheep fed on alkali-treated straw and concentrates,as complete diets or separate feeds

Twelve mature wethers were used in an experiment of change-over design to determine the effect of complete diet feeding on intake and digestibility of diets based on alkalitreated straw and a concentrate containing rolled barley and extracted soya bean meal. Two diets were used: D₁ with a 50:50, and D₂ with a 75:25 ratio of straw:concentrates on a dry matter basis. The straw and concentrates of each diet were given either separately (S) or as a complete diet (C). Complete diets gave a slightly, but not significantly higher intake (C, 86.5) and S, 82.5 g dry matter /kg W^0.75 per day). The separate method gave a significantly higher digestibility coefficient for dry matter (C, 62.2 and S, 65.5; P < 0.05) and for crude fibre (C, 57.2 and S, 62.5; P < 0.01). Water intake increased by 42.7 ml g^?1 Na derived from NaOH. There were no significant interactions between the method of feeding and the type of diet in intake and digestibility of the diets or in the intake of water.     

Ribosomal protein S3 is secreted as a homodimer in cancer cells

Protein secretion is a general phenomenon by which cells communicate with the extracellular environment. Secretory proteins, including hormones, enzymes, toxins, and antimicrobial peptides have various functions in extracellular environments. Here, we determined that ribosomal protein S3 (rpS3) is homodimerized and secreted in several cancer cell lines such as HT1080 (human fibrosarcoma) and MPC11 (mouse plasmacytoma). Moreover, we found that the secreted rpS3 protein increased in doxorubicin-resistant MPC11 cells compared to that in MPC11 cells. In addition, we also detected that the level of secreted rpS3 increased in more malignant cells, which were established with continuous exposure of cigarette smoke condensate. These findings suggest that the secreted rpS3 protein is an indicator of malignant tumors.     

Structural insight into the dual ligand specificity and mode of high density lipoprotein association of apolipoprotein D

Human apolipoprotein D (ApoD) occurs in plasma associated with high density lipoprotein. Apart from the involvement in lipid metabolism, its binding activity for progesterone and arachidonic acid plays a role in cancer development and neurological diseases. The crystal structures of free ApoD and its complex with progesterone were determined at 1.8A resolution and reveal a lipocalin fold. The narrow, mainly uncharged pocket within the typical beta-barrel accommodates progesterone with its acetyl side chain oriented toward the bottom. The cavity adopts essentially the same shape in the absence of progesterone and allows complexation of arachidonic acid as another cognate ligand. Three of the four extended loops at the open end of the beta-barrel expose hydrophobic side chains, which is an unusual feature for lipocalins and probably effects association with the high density lipoprotein particle by mediating insertion into the lipid phase. This mechanism is in line with an unpaired Cys residue in the same surface region that can form a disulfide cross-link with apolipoprotein A-II.     

Method for enhancing solubility of the expressed recombinant proteins in Escherichia coli

The production of correctly folded protein in Escherichia coli is often challenging because of aggregation of the overexpressed protein into inclusion bodies. Although a number of general and protein-specific techniques are available, their effectiveness varies widely. We report a novel method for enhancing the solubility of overexpressed proteins. Presence of a dipeptide, glycylglycine, in the range of 100 mM to 1 M in the medium was found to significantly enhance the solubility (up to 170-fold) of the expressed proteins. The method has been validated using mycobacterial proteins, resulting in improved solubilization, which were otherwise difficult to express as soluble proteins in E. coli. This method can also be used to enhance the solubility of other heterologous recombinant proteins expressed in a bacterial system.     

Effect of a strong cold storage induced desiccation on metabolic solutes,stock quality and regrowth,in seedlings of two oak species

Bare-root seedlings of pedunculate oak (Quercus robur L.) and northern red oak (Quercus rubra L.) were lifted in January and stored at 1.8°C, at 82% relative humidity, until their fresh weight declined by 33%. Root growth potential (RGP), fine root electrolyte leakage (REL), fine root water content (RWC), shoot tip water content (SWC), starch and metabolic solute contents in root and shoot, were measured just after lifting and after treatment. Survival of treated seedlings was also assessed in a field trial. RWC, SWC, REL, RGP were dramatically affected by desiccation during cold storage. In both species, root soluble carbohydrate level, inositol level and isocitrate level increased, whereas root starch level and shoot soluble carbohydrate level decreased. In northern red oak, treated seedlings had higher root contents of soluble carbohydrates, inositol and proline than in pedunculate oak. Moreover, treatment induced proline accumulation only in northern red oak roots. These differences could explain why field survival of treated seedlings was significantly better in northern red oak than in pedunculate oak.