A new loach, Cobitis shikokuensis (Teleostei: Cobitidae), from Shikoku Island, Japan

A new species of spinous loach, Cobitis shikokuensis, is described based on 297 specimens from Shikoku Island, Japan. The new species was formerly known as the Shikoku group of Cobitis takatsuensis. It can be distinguished from other species of Cobitis and closely related genera by a combination of the following characters: dorsal fin with 6 branched soft rays; anal fin with 5 branched soft rays; one brownish streak across eye from the tip of nose, no streak on cheek; a black spot smaller than eye diameter near the dorsal corner of the caudal fin base; 3–5 small brownish speckles on ventral side of caudal peduncle; high caudal peduncle with well-developed fleshy keels on dorsal and ventral side; a lamina circularis at base of dorsal part of pectoral fin absent; first branched soft ray of pectoral fin broad in males; pectoral soft rays widely branched from the approximate midpoint; last anal fin ray with 2 elements; interorbital width 11.2–17.1% of head length.     

Isolation and Purification of Colon Lamina Propria Dendritic Cells from Mice with Colitis

Dendritic cells are prime antigen presenting cells for stimulation of T cell immune responses. These cells are present in trace amounts in normal tissue. At sites of disease the increased frequency of these cells interacting with T cells may provide the basis for the release of pro-inflammatory mediators and contribute to localised cell and tissue damage. Studies on dendritic cells in the colon lamina propria of inflammatory bowel disease (IBD) mice have been limited due to the difficulties encountered in the isolation and purification of sufficient numbers of these cells. This is the first detailed, reproducible method provided in the literature for the isolation of colon lamina propria dendritic cells from mice with colitis, yielding optimum purity of cells and sufficient numbers to advance the study of dendritic cell function in the colons of mice. The most frequently used identification marker of murine DC is the CD11c surface antigen. We have adapted, combined, and improved procedures developed for the isolation of other cell types, to develop an efficient procedure for the isolation of dendritic cells from colon tissue. This protocol describes a step-by-step method for optimising the purity and recovery of lamina propria CD11c+ dendritic cells from mice colons.     

Iksookimia yongdokensis, a new cobitid fish (Pisces: Cobitidae) from Korea with a key to the species ofIksookimia

A new cobitid fish,Iksookimia yongdokensis, is described from rivers flowing to the southeastern coast of Korea. The species is distinguishable from its congeners by the following characteristics: reduced laminar circularis at the base of the pectoral fins in males; color pattern including 9–13 vertical bars on the body; 13–14 gill rakers; 17–20 caudal vertebrae; and small scales with a large focal area. Its unique discontinuous distribution on the Korean Peninsula is discussed and the biogeographic implications considered.     

Paleoecological significance of laminated diatomaceous oozes during the middle-to-late Pleistocene,North Atlantic Ocean (IODP Site U1304)

We examined diatom assemblages in a series of remarkable laminated diatomaceous ooze (LDO) horizons in the marine sediments from Integrated Ocean Drilling Program (IODP) Site U1304 to reconstruct the middle-to-late Pleistocene paleoceanographic evolution of the northern North Atlantic Ocean. Four confirmed diatom biohorizons combined with calcareous nannofossil and paleomagnetic stratigraphies established the chronological framework for the material. The planktonic, araphid, needle-like species Thalassiothrix longissima was the greatest contributor to the LDO facies. From the results of a principal component analysis using the percent abundances of 65 significant (p = 5%) diatom taxa, except for Tx. longissima, which was extremely dominant in almost all horizons observed, we identified two principal component (PC) axes. Taxa probably associated with the stratigraphic distribution of the major zonal marker Neodenticula seminae (ranging from 1.26 to 0.84 Ma in this ocean) loaded on PC1 with a high value. PC2 was related to the ocean surface temperature. The stratigraphic variability of the PC2 score indicated that switching between warm- and cold-water assemblages occurred concurrently with LDO deposition (or extreme Tx. longissima dominance) episodes in several horizons (particularly after 0.84 Ma), suggesting that the Subarctic Convergence (SAC) oceanic front passed over Site U1304 during Pleistocene glacial/interglacial cycles. Our floral evidence supports the model of nearly monospecific LDO formation caused by the enhanced physical accumulation of particular diatoms such as Tx. longissima. On the other hand, Nd. seminae, which probably contributes to spring phytoplankton blooms in the modern ocean, was present only between 1.26 and 0.84 Ma in this area. Thus, we infer that the main contributor of export flux in the regional annual primary production cycle would have shifted drastically from one of a spring phytoplankton bloom leader (Nd. seminae) to minor but mass dump assemblages (Tx. longissima etc.) in the mid-Pleistocene.     

Characterisation of columnar neurons and visual signal processing in the medulla of the locust optic lobe by system identification techniques

We describe visual responses of seventeen physiological classes of columnar neuron from the retina, lamina and medulla of the locust (Locusta migratoria) optic lobe. Many of these neurons were anatomically identified by neurobiotin injection. Characterisation of neuronal responses was made by moving and flash stimuli, and by two system identification techniques: 1. The first-order spatiotemporal kernel was estimated from response to a spatiotemporal white-noise stimulus; 2. A set of kernels to second order was derived by the maximal-length shift register (M-sequence) technique, describing the system response to a two-channel centre-surround stimulus. Most cells have small receptive fields, usually with a centre diameter of about 1.5°, which is similar to that of a single receptor in the compound eye. Linear response components show varying spatial and temporal tuning, although lateral inhibition is generally fairly weak. Second-order nonlinearities often have a simple form consistent with a static nonlinear transformation of the input from the large monopolar cells of the lamina followed by further linear filtering.Abbreviations LMC large monopolar cell - LVF long visual fibre - RF receptive field - SMC small monopolar cell - SVF short visual fibre     

四膜虫(Tetrahymena thermophila)核纤层的研究

采用非树脂包进埋去包埋超薄切片电镜技术,并结合选择性生化抽提方法以及间接免疫荧光染色方法显示,在四膜虫(Tetrahymena thermophila)细胞内存在典型的核纤层结构。蛋白分离纯化与免疫印迹法分析结果说明四膜虫细胞核纤层可能主要由分子量为66KD的多肽构成。蛋白分离纯化结果表明四膜虫细胞的核纤层蛋白可能不如高等动物细胞的丰富。     

Understanding the roles of nuclear A- and B-type lamins in brain development

The nuclear lamina is composed mainly of lamins A and C (A-type lamins) and lamins B1 and B2 (B-type lamins). Dogma has held that lamins B1 and B2 play unique and essential roles in the nucleus of every eukaryotic cell. Recent studies have raised doubts about that view but have uncovered crucial roles for lamins B1 and B2 in neuronal migration during the development of the brain. The relevance of lamins A and C in the brain remains unclear, but it is intriguing that prelamin A expression in the brain is low and is regulated by miR-9, a brain-specific microRNA.