烟草普通花叶病毒在烟草胞质体中的增殖

 本试验证明了TMV-RNA在有细胞核的烟草原生质体中能大量增殖,但在无核的胞质体中却难以增殖。     

Complementary process to response bias in the centromedian nucleus of the thalamus

Activity in several areas of the human brain and the monkey brain increases when a subject anticipates events associated with a reward, implicating a role for bias of decision and action. However, in real life, events do not always appear as expected, and we must choose an undesirable action. More than half of the neurons in the monkey centromedian (CM) thalamus were selectively activated when a small-reward action was required but a large-reward option was anticipated. Electrical stimulation of the CM after a large-reward action request substituted a brisk performance with a sluggish performance. These results suggest involvement of the CM in a mechanism complementary to decision and action bias.     

Total synthesis of norzoanthamine

Norzoanthamine, an alkaloid isolated from Zoanthus sp., can suppress the loss of bone weight and strength in ovariectomized mice. Norzoanthamine derivatives can also strongly inhibit the growth of P-388 murine leukemia cell lines and human platelet aggregation. However, norzoanthamine's densely functionalized complex stereostructure and scarce availability from natural sources have proved a synthetic challenge. We report the stereoselective total synthesis of norzoanthamine in 41 steps, with an overall yield of 3.5% (an average of 92% yield each step).     

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.     

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.     

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.     

A Case Report of a Malignant Fibrous Histiocytoma in a T-cell Receptor β Chain and p53 Double-knockout Mouse

A subcutaneous tumor was found in the right abdomen of a 16-week-old male TCRβ and p53 double-knockout mouse. The tumor had indistinct borders with the surrounding tissue. The cut surface after formalin fixation was pale yellowish white, partially dark red and partly white. Histologically, the tumor was composed of three distinct regions. The first region showed pleomorphic cells arranged in sheets. The second region showed spindle cells arranged in interlacing fascicles. The final region contained a mixture of the above mentioned two types of cells. Furthermore, a small amount of collagen fibers, round cells, multinucleated giant cells, and cells with eosinophilic granules were observed between these tumor cells. Immunohistochemical examination and electron microscopy identified that the pleomorphic cells and spindle cells were histiocytes and fibroblasts, respectively, and that the round cells were undifferentiated mesenchymal cells. Based on these findings, the tumor was diagnosed as a malignant fibrous histiocytoma.     

Practical aspects of the fertility of dairy cattle

To establish sustainability in the dairy industry, it is important that cows become pregnant at a biologically optimal time and at an economically profitable interval after calving. In this review, the results obtained from Holstein cattle in an experimental herd for dairy research are summarized. First, the effect of age at first calving of heifers on productive and reproductive performance was examined. A reduction in calving age from 25.1 to 21.5 months with the same growth rate during the first 12 months after birth had no negative effects on the heifers' performance. Second, the postpartum follicular dynamics of lactating cows were traced in relation to their fertility, and the emergence and fate of cystic ovarian follicles were examined. The premature initiation of ovarian activity does not always improve the fertility of cows as indicated by the number of days open. Third, the occurrences of anestrous ovulation during the early postpartum period were analyzed with reference to the frequency of reversion to anestrus. The premature onset of estrous activity also did not improve fertility, and relapse back into anestrus after the onset of the estrous cycle often occurred during the breeding period. Fourth, some indices for the occurrence of postpartum reproductive events were evaluated as an indicator of the reproductive performance of lactating cows. The milk yield and percentage of body weight loss could be indicators for reproductive events. Finally, the potency of a pedometry system for the detection of typical and atypical estrous behaviors of heifers and lactating cows was evaluated in terms of efficiency and accuracy. The location of the pedometers and housing conditions for the animals affected the estrus detection of the system. These results represent the reproductive potential of modern high-yielding dairy cattle and provide a baseline to evaluate their reproduction.