New observations on the bioluminescence of echinoderms

Bioluminescence has been observed in two species of Ophiuroidea, six species of Asteroidea, nine species of Holothuroidea and two species of Crinoidea. The luminescent responses are described and the intensities and time courses of the responses of some species are given.
Histological investigations have indicated possible luminous cells in the Holothuroidea, but the results in other classes remain equivocal. Preliminary analyses of the chemistry of bioluminescence indicate that a similar system may be responsible for bioluminescence in all four classes, although the visible manifestations of the system vary considerably.     

The periodate oxidation of bovine bone sialoprotein, and some observations on its structure

1. Bovine bone sialoprotein (mol.wt. 23000) contains N-acetylneuraminic acid and N-glycollylneuraminic acid, fucose, galactose, mannose, N-acetylgalactosamine and N-acetylglucosamine residues in the form of a very small number, perhaps one, of highly branched oligosaccharide structures linked covalently to peptide. 2. Periodate oxidation of the sialoprotein results in quantitative destruction only of the sialic acid and fucose residue consistent with the earlier findings of their positions as terminal groups. 3. Terminal sialic acid residues are attached to galactopyranose residues by 2,3-linkages, and to some N-acetylgalactosamine residues (at C-6). 4. Sequential Smith degradation indicates that N-acetylgalactosamine residues may be present as points of branching (linked in C-1, C-3 and C-6) and N-acetylglucosamine residues are located in the inner part of the structure, adjacent to the carbohydrate–peptide bond(s). 5. Mannose residues appear to be linked in the 1,3-positions.     

Patterns of sequence variation in the mitochondrial D-loop region of shrews

Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews (genus Sorex) for the region between the tRNA(Pro) and the conserved sequence block-F revealed variable numbers of 79-bp tandem repeats. These repeats were found in all 19 individuals sequenced, representing three subspecies and one closely related species of the masked shrew group (Sorex cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an adjacent 76-bp imperfect copy of the tandem repeats. One individual was heteroplasmic for length variants consisting of five and seven copies of the 79-bp tandem repeat. The sequence of the repeats is conducive to the formation of secondary structure. A termination-associated sequence is present in each of the repeats and in a unique sequence region 5' to the tandem array as well. Mean genetic distance between the masked shrew taxa and the pygmy shrew was calculated separately for the unique sequence region, one of the tandem repeats, the imperfect repeat, and these three regions combined. The unique sequence region evolved more rapidly than the tandem repeats or the imperfect repeat. The small genetic distance between pairs of tandem repeats within an individual is consistent with a model of concerted evolution. Repeats are apparently duplicated and lost at a high rate, which tends to homogenize the tandem array. The rate of D- loop sequence divergence between the masked and pygmy shrews is estimated to be 15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid sequence evolution in shrews may be due either to their high metabolic rate and short generation time or to the presence of variable numbers of tandem repeats.      

The response of tropical Atlantic decapod crustaceans to artificially lighted trawls

Micronektonic decapod crustaceans were sampled repeatedly ata depth of 200 ± 25 m at two positions centred on 20°30'N,19°40'W and 31°10'N, 21°05'W to assess their responseto an artificial light fitted to an opening/closing rectangularmidwater trawl. Of the 20 decapod species identified, the numbersand biomass of the three numerically dominant diel migrantsOplophorus spinostu, Sysiellaspis debilis and Acanthephyra purpureawere significantly reduced in hauls taken with the artificiallight switched on, when compared with catches with it switchedoff. There was little measurable response in the frequentlyoccurring species Gennadas valens or Gennadas brevirostris,or in other less frequently occurring species.     

大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育

本实验用免疫组织化学ＡＢＣ法研究了大鼠胼胝体内神经肽Ｙ免疫反应阳性（ＮＰＹ－ＩＲ）纤维的生后发育。结果发现,许多ＮＰＹ－ＩＲ纤维在大鼠出生时便存在于胼胝体内。ＮＰＹ－ＩＲ胼胝体纤维的密度在生后１周内继续逐渐增高,在第２周内达到最高峰。之后,ＮＰＹ－ＩＲ胼胝体纤维的密度逐渐下降,至第３周末时接近成年时的水平,即仅有少量ＮＰＹ－ＩＲ纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多ＮＰＹ－ＩＲ胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。