The caudal spinal cord of coho salmon (Oncorhynchus kisutch): Immunocytochemical evidence of a “caudal serotoninergic system”

Summary The caudal spinal cord of the coho salmon was investigated by means of immunocytochemistry using antisera against serotonin, urotensin I, urotensin II, somatostatin and a urea-extract of bovine Reissner's fiber (AFRU). Populations of serotonin-immunoreactive (IR) neurons were found rostral and dorsal to the urophysis in close spatial association with caudal secretory neurons. Thick, smooth serotonin-IR processes extended toward the external surface of the spinal cord where they displayed conspicuous terminal dilatations. Thin, beaded serotonin-IR fibers appeared to innervate populations of caudal secretory and somatostatin-IR cerebrospinal fluid-contacting neurons. Most caudal neurosecretory cells displayed both urotensin I and urotensin II immunoreactivities; only a minority reacted exclusively with either urotensin I or urotensin II antisera. Urotensin II-IR and somatostatin-IR cerebrospinal fluid (CSF)-contacting neurons were found as an integral component of the central canal wall in the caudal spinal cord and filum terminale; their dendritic processes appeared to contact Reissner's fiber, which displayed a weak AFRU-immunoreactivity while inside the central canal, but became strongly reactive in the interior of the terminal ventricle as it formed the massa caudalis. The distribution of serotoninergic processes points to a regulatory role in the function of caudal secretory and CSF-contacting neurons and to a putative serotonin release into the subarachnoid space and/or meningeal vasculature. It is also suggested that the CSF-contacting neurons of the central canal may participate in a feedback mechanism controlling the secretory activity of the subcommissural organ.Supported by Grant A/1095-1 from the International Foundation for Science, Sweden, to C.Y.; Grant I/63-476 from Volkswagen-Stiftung to E.R.; and Grant S-85-39 from the Dirección de Investigaciones, Universidad Austral de Chile     

Chromosome-specific subsets of human alphoid DNA identified by a chromosome 2-derived clone

We have cloned an alphoid DNA fragment, pBS4D, from the DNA of a human-hamster hybrid cell line containing chromosome 2 as its only cytologically detectable human component. Under high stringency conditions, pBS4D hybridized in situ mostly to chromosome 2 and to a lesser extent to chromosomes 18 and 20. Restriction analysis using the DNA from selected somatic hybrid cell lines revealed that the genomic organization of this alphoid DNA differs on each of these three chromosomes.     

Cobalt-substituted derivatives ofCarcinus hemocyanin

Summary Four derivatives ofCarcinus maenas hemocyanin containing Co(II) in the active site have been prepared under different experimental conditions. Two of them contain one Co(II) ion/active site and most probably represent isomeric forms containing Co(II) either in the fast-reacting or in the slow-reacting position within the active site. A third derivative contains two Co(II) ions active site, which reproduces the metal/protein stoichiometry of native hemocyanin. The fourth derivative is a metal hybrid form containing one Cu(I) ion and one Co(II) ion/active site. The derivatives have been characterized by absorption, circular dichroic and fluorescence spectroscopies. The results indicate that in all derivatives the metal is bound with a low coordination number, in agreement with the presence of three histidine residues/copper ion in the native protein. The two alternative metal-binding positions have different structures as shown by the different spectroscopic properties of the bound Co(II) ions. A marked hyperchromic effect on the optical absorption of Co(II) is observed as a result of the presence of a metal ion in the neighbouring metal-binding position in the active site.     

Anatomy of the hominoid wrist joint: Its evolutionary and functional implications

Observations on the behavior of living hominoids show generic differences in the use and posture of the wrist joint. Both orang-utans and hylobatids usually use the wrist in suspensory behaviors. However, orang-utans emphasize markedly adducted and flexed wrist postures, while hylobatids emphasize violent forearm and wrist rotation. African apes, especially the gorilla, use the wrist more frequently than other hominoids for terrestrial quadrupedal weight-bearing. Humans use the wrist less frequently for supportive purposes than do other hominoids. These behavioral differences correspond to structural specializations in the proximal carpal joint of each of the hominoid genera. Although each of the hominoid genera has apparently modified its proximal carpal joint best to serve its characteristic behaviors, all hominoids share a unique proximal carpal joint that permits approximately 160ℴ of forearm rotation. The hylobatid proximal carpal joint is specialized in exhibiting a marked development of those structures limiting forearm rotation, but it is in most respects the least derived— that is, closest to the nonhominoid anthropoids. Chimpanzees show a proximal carpal joint that is more generalized than those of the other great apes but more derived than that of hylobatids. The human and gorilla proximal wrist joints, on the other hand, show marked modifications for weight-bearing in terrestrial behaviors. Orang-utans have the most derived proximal carpal joint, which in many respects parallels that of the slow-climbing nonhominoid primates. The comparative anatomy and structural specializations of the wrist joint support (a) an early divergence of hylobatids from the common hominoid stock, (b) a common ancestry for gorillas and humans separate from the other hominoids, and (c) a long independent evolutionary period for orang-utans since their divergence from the common hominoid stock, or one that was marked by strong selection pressures for wrist specializations. Unfortunately, the generalized condition of the chimpanzee’s wrist joint and the very derived condition of the orang-utan wrist provide uncertain evidence as to which of the two was first to diverge from the common hominoid stock. Identification of hominoid wrist specializations as reflecting real phylogenetic relationships or parallelisms depends on how well the phytogeny inferred from wrist morphology accords with those arrived at from the study of other systems.     

Vaccinia virus preferentially enters polarized epithelial cells through the basolateral surface.

The uptake of vaccinia virus in polarized epithelial cells was studied to determine whether the site of entry was confined to either the apical or the basolateral membrane. Virus infection was monitored with a recombinant vaccinia virus carrying the luciferase reporter gene. Using cell lines MDCK and MDCK-D11, a clonal line with high transepithelial electrical resistance, we determined that vaccinia virus preferentially enters through the basolateral membrane. The possibility that there is a polarized cell surface distribution of vaccinia virus receptors which may be involved in systemic poxvirus infections is discussed.     

Infraciliature, morphogenesis and life cycle of Endosphaera terebrans (Suctoria, Tokophridae)

The morphology, infraciliature, and life cycle of Endosphaera terebrans, a suctorian endocommensal of peritrichs, have been studied with the aid of silver impregnation. The life cycle of Endosphaera terebrans begins with infection of the host cell by a small larva. The swarmer has a pointed needle-like cellular projection and two rings of cilia. The swarmer penetrates the the peritrich, loses the cilia, and then matures into an adult. The infraciliature of the adult form has four rows of barren kinetosomes that lack kinetodesmal fibers. By endogenous budding, a migratory larva is produced that leaves the host cell through the peristomial disc and that can infect other peritrichs.     

The 32-kilodalton envelope protein of vaccinia virus synthesized in Escherichia coli binds with specificity to cell surfaces.

The nature of interaction between vaccinia virus and the surface of host cells as the first step in virus infection is undefined. A 32-kDa virus envelope protein has been identified as a cell surface binding protein (J.-S. Maa, J. F. Rodriguez, and M. Esteban, J. Biol. Chem. 265:1569-1577, 1990). To carry out studies on the structure-function relationship of this protein, the 32-kDa protein was obtained from Escherichia coli cells harboring the expression plasmid pT7Ek32. The recombinant polypeptide was found to have structural properties similar to those of the native virus envelope protein. Binding studies of 125I-labeled 32-kDa protein to cultured cells of various origins revealed that the E. coli-produced 32-kDa protein exhibited selectivity, specificity, and saturability. Scatchard analysis indicated about 4.5 x 10(4) sites per cell with a high affinity (Kd = 1.8 x 10(-9) M), suggesting interaction of the 32-kDa protein with a specific receptor. The availability of large quantities of the 32-kDa virus protein in bacteria will permit further structural and functional studies of this virus envelope protein and facilitate identification of the specific cell surface receptor.     

SO2-catalysed prehydrolysis of coniferous wood for ethanol production

Summary This paper reports studies of large scale, 1500 kg/h, SO₂-catalysed prehydrolysis of coniferous wood chips, samples then being hydrolyzed by a wood-saccharifying enzyme system followed by fermentation to ethanol in the laboratory. Hemicellulose hydrolysis using SO₂ catalyst (prehydrolysis) was found to be more effective than steam alone (autohydrolysis). Prehydrolysis time was 2 min, with steam pressure at 1.2 to 1.7 MPa (175 to 250 psig), and SO₂ catalyst 2.0 to 2.6% on dry wood. The amount of sugars recovered upon enzyme saccharification of the prehydrolysed wood was about 70% of the weight of the wood. When these combined hemicellulose and cellulose sugars were fermented by a pentose-fermenting strain of yeast,Pichia stipitis R, 372 L ethanol/tonne of (dry) wood was obtained.     

Desangeloylshairidin,X-ray structure determination of a sesquiterpene lactone from Guillonea scabra

The structure and absolute configuration of desangeloylshairidin, a guaianolide isolated from Guillonea scabra, have been established by X-ray diffraction analysis. No conformational change was observed in its seven-membered ring between the crystal and deuterochloroform solution states.