Loss of imprinting of Igf2 alters intestinal maturation and tumorigenesis in mice

Loss of imprinting (LOI) of the insulin-like growth factor II gene (IGF2) is an epigenetic alteration that results in a modest increase in IGF2 expression, and it is present in the normal colonic mucosa of about 30% of patients with colorectal cancer. To investigate its role in intestinal tumorigenesis, we created a mouse model of Igf2 LOI by crossing female H19+/- mice with male Apc+/Min mice. Mice with LOI developed twice as many intestinal tumors as did control littermates. Notably, these mice also showed a shift toward a less differentiated normal intestinal epithelium, reflected by an increase in crypt length and increased staining with progenitor cell markers. A similar shift in differentiation was seen in the normal colonic mucosa of humans with LOI. Thus, altered maturation of nonneoplastic tissue may be one mechanism by which epigenetic changes affect cancer risk.     

Effect of temperature, age class, and growth on induction of aestivation in Japanese sandeel (Ammodytes personatus) in Ise Bay, central Japan

We investigated the effects of temperature, age class, and growth on induction of aestivation in the Japanese sandeel (Ammodytes personatus) by means of rearing experiments and field surveys in Ise Bay, central Japan. Acoustic surveys and sampling of shoaling and aestivating sandeels indicated that the sandeels completed aestivation when the water temperature increased to 17–20°C. A rearing experiment showed that the mortality of sandeels reared without sand was greater than it was with sand, under replete feeding conditions. In a non‐aestivation rearing experiment without sand, the condition factor of the sandeels decreased when water temperatures exceeded 20°C, although they were fed to repletion. These results suggest that aestivation is induced by rising seawater temperature and plays an important role in energy conservation. The age‐1 group tended to start aestivation earlier than the age‐0 group in the field. Within the age‐0 group, larger sandeels tended to enter aestivation earlier. These observations indicate that fat reserves are an important cue to start aestivation.     

Analysis of juvenile tuna movements as correlated random walk

We explore how a stochastic model provides the most promising avenue towards predicting fish movement. To construct a stochastic model describing fish movement, trajectories of ten juveniles in a water tank were analyzed from a stochastic point of view. The heading angle was defined as a random variable. Our analysis found that the most probable forward heading angle was between 0° and 22.5° (probability ~78%), followed by angles between 22.5° and 45° (probability ~10%). We also found that the choice of future heading angle depends on the current heading angle. Therefore, we treated heading angle state as a first-order Markov process and constructed a correlated random walk model describing juvenile movement in a water tank. Our stochastic model simulated a trajectory similar to observed trajectories. We used the model as a tool for estimating the probability distribution of potential fish path outcomes. We derived the distribution of potential outcomes from a large number of simulations (N = 1000) and investigated these trajectories. We collected a set of juvenile trajectories that collided with the tank and estimated the probability of juvenile collisions with the tank.     

Alanine racemase activity in the microalga <Emphasis Type="Italic">thalassiosira</Emphasis> sp.

ABSTRACT:   In this paper, the authors report the detection of alanine racemase activity in the marine diatom Thalassiosira sp. Since the Thalassiosira sp. was cultured under germ-free conditions, it appeared that D-alanine was not derived from bacteria but was produced through catalysis by algal alanine racemase. The rate of conversion of L-alanine to D-alanine was approximately the same as that for the reverse reaction, and the enzyme catalyzed the equilibration of the D- and L-forms. The crude enzyme preparation obtained from the cells at the stationary phase of the growth cycle had an optimal pH of approximately 9.5. The Lineweaver–Burk analysis showed that the K _m for D- and L-alanine was 16.5 mM and 29.4 mM, respectively. It appears that the enzyme is highly specific for D- or L-alanine because it does not catalyze the racemization of other amino acids. In addition, after gel filtration, the enzyme did not require exogenous pyridoxal 5'-phosphate (PLP) for its activity, however, the effects of several chemicals suggest that the enzyme may be PLP-dependent. The enzyme is more similar to that found in invertebrates when compared with that found in bacteria. This is the first report on the occurrence of alanine racemase activity in the microalga Thalassiosira sp.     

Monitoring of the genetic variability of the hatchery and recaptured fish in the stock enhancement program of the rare species barfin flounder <Emphasis Type="Italic">Verasper moseri</Emphasis>

ABSTRACT:   In relation to the stock enhancement program for barfin flounder, hatchery juveniles produced in 2001 were genotyped using microsatellite DNA markers (msDNA) and then released to natural waters. Subsequently, recaptured individuals, designated as 'tentative recaptured', were examined using msDNA. In order to evaluate the effectiveness of the stock enhancement program, pairwise F _ST and genic differentiation tests were used to estimate the genetic divergence between the wild samples, the hatchery broodstock, and the tentative recaptured samples. Analysis showed significant differentiation among these three groups. Pedigree determination by msDNA was used to establish the origin of the tentative recaptured individuals, in order to elucidate whether they were hatchery produced, 'real recaptured', or wild specimens. Wild individuals were not found. The effective population size of the real recaptured stock was very low ( N _e = 16.6). Equal family survivability was observed between the released and real recaptured stocks, indicating that the genetic variability of the released stock was maintained in the natural environment. Future broodstock management, breeding designs, and family contribution equalization of the offspring to be released will be required in this rare species to avoid unintended genetic differentiation between the wild population and the hatchery broodstock.     

A simple, rapid method for gizzerosine analysis in fish meal by paper electrophoresis

We established a simple, rapid method for gizzerosine analysis in fish meal. Gizzerosine was extracted from fish meal with 0.1?N HCl solution. Samples and standard gizzerosine solutions were absorbed onto a paper disc, which was then set on electrophoresis paper for 18?min, and the paper was dried. Gizzerosine was visualized with Pauly??s reagent, and the intensity of the colored spots was digitized and calculated by image processing method software. We achieved successful separation of gizzerosine from other Pauly??s reagent-positive components in fish meal extracts. The linearity of gizzerosine estimation using this method was within the range 30?C1000?ng (R ²?=?0.99). Gizzerosine was satisfactorily detected and completely separated from histamine and other Pauly??s reagent-positive compounds. This method does not require expensive instruments or tedious pretreatment to eliminate interfering compounds, such as histamine or histidine. It also uses less reagent compared with high-performance liquid chromatography. Moreover, it is a simple, rapid, sensitive, and reproducible method. It is suitable for monitoring gizzerosine in fish meal products that contain as little as 10?ppm gizzerosine.     

Allozyme variation of littleneck clam Ruditapes philippinarum and genetic mixture analysis of foreign clams in Ariake Sea and Shiranui Sea off Kyushu Island, Japan

ABSTRACT:   Allozyme variation of the littleneck clam Ruditapes philippinarum was evaluated in four samples from Nameishi and Matsuo in the Ariake Sea, Ryugatake and Ushibuka in the Shiranui Sea off Kyushu Island, Japan, and in one sample from Jinzhou, China, in the Bohai Sea. A Ruditapes bruguieri sample imported from the Korean Bay off Nampo, North Korea was also studied. Among the R. philippinarum samples, heterozygosity varied from 0.265 to 0.301 and F _IS estimates indicated significant homozygosity excess in 15 of 40 loci analyzed. Deviations from Hardy–Weinberg equilibrium were significant in all samples ( P  < 0.05). Pairwise F _ST estimates indicate that genetic differences between the Chinese and Japanese samples were very low, but significantly different from zero. Mixture proportions with 95% confidence intervals of Chinese R. philippinarum in Nameishi and Matsuo were estimated at 0.4098 [0.2512, 0.5705] and 0.4899 [0.3262, 0.6540], respectively. However, genetic invasion of stocked Chinese R. philippinarum into wild populations in the Ariake Sea remains uncertain due to the low precision of the estimates caused by the high similarity of allele frequencies between Jinzhou and the Ariake Sea.     

Large granular lymphocyte lymphoma in the skin and urinary bladder of a dog

A 10-year-old female Cavalier King Charles Spaniel presented with hematuria, pollakiuria and skin rash. Based on the histopathological and cytological examination of the skin and bladder mucosa, the dog was diagnosed with large granular lymphocytic (LGL) lymphoma of the bladder and skin. The dog responded well to the initial chemotherapy with nimustine for 3 months. Since recurrence of skin erosion and bladder wall thickening were observed, the dog was subsequently administered chemotherapy with other anticancer drugs, including chlorambucil, vincristine, doxorubicin, L-asparaginase, cytosine arabinoside, and cyclophosphamide. The dog survived for 11 months and died due to tumor-related disseminated intravascular coagulation. This is the first report of a canine case of LGL lymphoma in the skin and bladder.     

Occurrence of rocket larkspur witches’ broom caused by “<Emphasis Type="Italic">Candidatus</Emphasis> Phytoplasma asteris” in Japan

In October 2001, a disease of rocket larkspur (Cosolida ambigua (L.) P. W. Ball et Heyw), characterized by witches’ broom, yellows and virescence of flowers, was found in Yakage Town in Okayama Prefecture. Electron microscopy revealed the presence of phytoplasma-like bodies in the phloem of diseased plants. The causal phytoplasma was identified as “Candidatus Phytoplasma asteris” based on 16S rDNA sequence analysis, and demonstrated to be acquired by the leafhopper Macrosteles striifrons. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB258330.