Growth induced by pulsatile infusion of an amidated fragment of human growth hormone releasing factor in normal and GHRF-deficient rats

The discovery of human pancreatic growth hormone releasing factors (GHRFs) and subsequent characterization of human hypothalamic GHRF has led to studies on the role of these peptides in stimulating growth hormone (GH) release, and attempts to use GHRF peptides to increase growth rates in short children are already underway. However, there is no experimental evidence in animals that exogenous GHRF promotes growth in vivo. Although anaesthetized rats release GH reproducibly in response to GHRF injections, the responses in conscious male rats are much more variable, perhaps because of their highly episodic endogenous GH secretory pattern. In contrast, female rats secrete GH in a more continuous pattern and respond reproducibly to repeated injections of GHRF. We report here that it is possible to establish a 'male' type of GH secretory pattern in normal female rats by long-term pulsatile intravenous (i.v.) infusions of the active human GHRF fragment GHRF (1-29)NH2. We found that this treatment accelerates growth and increases pituitary GH content, whereas continuous infusions of this GHRF fragment at the same daily dose are ineffective. Pulsatile, but not continuous GHRF also stimulates growth in animals made GHRF-deficient by neonatal monosodium glutamate treatment. Thus exogenous GHRF will stimulate growth in both GHRF-deficient and normal animals provided it is administered in an appropriate pattern.     

Proteomic analysis of active multiple sclerosis lesions reveals therapeutic targets

Understanding the neuropathology of multiple sclerosis (MS) is essential for improved therapies. Therefore, identification of targets specific to pathological types of MS may have therapeutic benefits. Here we identify, by laser-capture microdissection and proteomics, proteins unique to three major types of MS lesions: acute plaque, chronic active plaque and chronic plaque. Comparative proteomic profiles identified tissue factor and protein C inhibitor within chronic active plaque samples, suggesting dysregulation of molecules associated with coagulation. In vivo administration of hirudin or recombinant activated protein C reduced disease severity in experimental autoimmune encephalomyelitis and suppressed Th1 and Th17 cytokines in astrocytes and immune cells. Administration of mutant forms of recombinant activated protein C showed that both its anticoagulant and its signalling functions were essential for optimal amelioration of experimental autoimmune encephalomyelitis. A proteomic approach illuminated potential therapeutic targets selective for specific pathological stages of MS and implicated participation of the coagulation cascade.     

Exome sequencing identifies GRIN2A as frequently mutated in melanoma

The incidence of melanoma is increasing more than any other cancer, and knowledge of its genetic alterations is limited. To systematically analyze such alterations, we performed whole-exome sequencing of 14 matched normal and metastatic tumor DNAs. Using stringent criteria, we identified 68 genes that appeared to be somatically mutated at elevated frequency, many of which are not known to be genetically altered in tumors. Most importantly, we discovered that TRRAP harbored a recurrent mutation that clustered in one position (p. Ser722Phe) in 6 out of 167 affected individuals (～4%), as well as a previously unidentified gene, GRIN2A, which was mutated in 33% of melanoma samples. The nature, pattern and functional evaluation of the TRRAP recurrent mutation suggest that TRRAP functions as an oncogene. Our study provides, to our knowledge, the most comprehensive map of genetic alterations in melanoma to date and suggests that the glutamate signaling pathway is involved in this disease.     

The opsins of the vertebrate retina: insights from structural,biochemical, and evolutionary studies

The vertebrate retina contains several classes of visual pigments responsible for such diverse functions as image- and nonimage-forming vision, the entrainment of circadian cycles, and the pupilary light response. With vision being vital to the survival of many species, the elucidation of the structural and biochemical properties of visual pigments has been the focus of a large body of research that has led to rapid advances in the field of photoreception. In this review, the current understanding of the structure, function, biochemistry, and evolution of the opsins that make up the photopigments in the vertebrate retina will be reviewed. These include the rod and cone opsins, melanopsin, RGR, peropsin, and VA-opsin. The goal is to highlight important questions that have been answered and to define some of the remaining questions in the field that will provide future directions for research.     

Calcineurin activity is required for the completion of cytokinesis

Successful completion of cytokinesis requires the spatio-temporal regulation of protein phosphorylation and the coordinated activity of protein kinases and phosphatases. Many mitotic protein kinases are well characterized while mitotic phosphatases are largely unknown. Here, we show that the Ca²⁺- and calmodulin-dependent phosphatase, calcineurin (CaN), is required for cytokinesis in mammalian cells, functioning specifically at the abscission stage. CaN inhibitors induce multinucleation in HeLa cells and prolong the time cells spend connected via an extended intracellular bridge. Upon Ca²⁺ influx during cytokinesis, CaN is activated, targeting a set of proteins for dephosphorylation, including dynamin II (dynII). At the intracellular bridge, phospho-dynII and CaN are co-localized to dual flanking midbody rings (FMRs) that reside on either side of the central midbody ring. CaN activity and disassembly of the FMRs coincide with abscission. Thus, CaN activity at the midbody plays a key role in regulating the completion of cytokinesis in mammalian cells.     

Diatom flora of Mink Creek, Idaho, USA

Diatoms were collected from an open-canopy and closed-canopy site on Mink Creek, Bannock County, Idaho, a third-order Rocky Mountain stream. Ninety diatom taxa were identified. Achnanthes minutissima Kuetz. And Navicula lanceolata (Ag. ) Kuetz. dominated the open-canopy site, whereas Cocconeis placentula var. euglypta (Ehr.)CI. comprised greater than 40% of the diatom assemblage at the closed-canopy site. Seven of the 10 most important diatoms were present at both sites. A high degree of similarity was evident between natural and artificial substrates at both sites. Although most taxa were present at both sites, it is apparent from this study that differences in the abundance of taxa occur according to variations in light.     

Benthic community structure in two adjacent streams in Yellowstone National Park five years after the 1988 wildfires

Physical characteristics, benthic macroinvertebrates, and periphyton assemblages in two adjacent headwater streams in Yellowstone National Park were evaluated five years after the 1988 wildfires. The catchment of one stream was burned by wildfire (burned stream) while the other catchment was unburned (unburned stream). Physical measures revealed channel alteration in the burned stream relative to the unburned stream Periphyton biomass was lower in the burned than the unburned stream (29.2 vs. 50.5 g/m 2 AFDM, respectively), further demonstrating the unstable physical conditions of that system. Kendall's coefficient of concordance (an index of similarity) between diatom assemblages was 0.22, indicating distinct assemblage composition between streams. Navicula permitis Hust. was the most abundant diatom in the burned stream while Hannaea arcus (Ehr.) Patr. was dominant in the unburned stream. Macroinvertebrate taxa richness, density, and biomass were all greater in the unburned stream, although Chironomidae was the most abundant taxon in both streams. Results suggest the removal of terrestrial/riparian vegetation by wildfire can directly influence benthic assemblages by altering the inherent disturbance regime of the physical habitat templet.     

Cyclic nucleotide levels in the perfused rat heart subjected to hypoxia.

Isolated rat hearts were subjected to hypoxic perfusion on a recirculating Langendorff apparatus. Following a 30-min-period of aerobic stabilization the hearts were perfused for 30 min with media equilibrated with 84% N2, 12%O2 and 4% CO2. At the end of the hypoxic period myocardial concentrations of cyclic AMP and cyclic GMP were determined by radioimmunoassay. Exposure to hypoxia resulted in a significant increase in cyclic AMP (p less than 0.01) and a decrease in cyclic GMP (p less than 0.05) as compared to hearts perfused for 60 min with media gassed with 96% O2. 4% CO2.     

Degradation of encephalitogenic protein in aerobic ascorbic acid solutions.

Aerobic ascorbic acid solutions are capable of extensively cleaving the peptide chain of the myelin basic protein. Cleavage occurred most readily with C-terminal to aspartic acid, serine, threonine, glutamic acid and leucine residues.