Net depth response of a depth-controllable (towed) gillnet for fish sampling

SUMMARY: Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.     

Rice <Emphasis Type="Italic">terpene synthase 18</Emphasis> (<Emphasis Type="Italic">OsTPS18</Emphasis>) encodes a sesquiterpene synthase that produces an antibacterial (<Emphasis Type="Italic">E</Emphasis>)-nerolidol against a bacterial pathogen of rice

Plant volatile compounds, including terpenes, are known to be involved in the rice defense system. In the present analysis of a terpene synthase, OsTPS18, in rice, we found that OsTPS18 was localized in the cytoplasm and synthesized the sesquiterpenes (E)-nerolidol and (E)-β-farnesene. The amounts of (E)-nerolidol and (E)-β-farnesene increased after jasmonic acid (JA) treatment. (E)-Nerolidol had significant antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo). These results suggest that (E)-nerolidol plays an important role in JA-induced resistance against Xoo and that it functions as an antibacterial compound in rice.     

牛体外受精时老化卵对受精率与染色体异常发生的影响

通过延长体外培养时间得到牛老化卵，对其体外受精率与染色体的异常发生进行了研究，体外受精48h后的受精率，46h培养组与22h和34h培养组之间差异显著（P＜0．05），随着老化时间的延长，受精率及胚胎发育速度明显降低。染色体分析结果表明，46h组的受精卵的染色体异常发生率为61．6％，22h组44．6％，2组之间差异显著（P＜0．05），单倍体（n=31)的发生率也随着老化时间的延长而增加，这些单倍体的性染色体的构成表明，含有X－性染色体的胚的出现率显著高于含有Y－染色体的胚的出现率（P＜0．05）。单倍体的发生是由卵的老化而引起单一配子的孤雌发生，体外培养时间的延长对正常的2倍体的性别无明显影响。     

Involvement of microaerophilic iron-oxidizing bacteria in the iron-oxidizing process at the surface layer of flooded paddy field soil

Journal of Soils and Sediments - To reveal whether microaerophilic Fe(II)-oxidizing bacteria (FeOB) participate in the Fe(II) oxidation at the oxic-anoxic interface in flooded paddy field soil,...     

Cellularity of developing subcutaneous adipose tissue in Landrace and Meishan pigs: Adipocyte size differences between two breeds

Experiments were designed to compare the adipocyte cellularity of subcutaneous adipose tissue between growing Landrace (low backfat) and Meishan (high backfat) pigs at 1 week, 3 weeks, 6 weeks, 3 months and 5 months of age. As pigs aged, body weight and backfat thickness of both breeds significantly increased. When compared at equal ages, backfat thickness adjusted to equal body weight was greater for Meishan pigs. The mean diameter of fat cell size also increased with age, and by 6 weeks adipocytes from both outer and inner layers of subcutaneous adipose tissue were larger in Meishan pigs. At 5 months, approximately 80% of the adipose tissue mass in Meishan pigs was attributable to adipocytes measuring 95–165 µm in diameter, whereas adipocytes of 75–145 µm comprised most of the tissue mass in the Landrace. Although the contribution of smaller adipocytes (25–45 µm) to the tissue volume was negligible, both breeds showed a biphasic diameter distribution at all ages, suggesting that adipocyte hyperplasia is still active. Our results demonstrate that cellularity differences exist between the subcutaneous adipose tissues of Landrace and Meishan pigs, and adipocyte hypertrophy is the most overwhelming contributor to the greater backfat deposition for Meishan pigs.     

A simultaneous estimation procedure for the parameters of the maximum size–density line and self-thinning curve to predict stand development of fast-growing tropical species

A simultaneous estimation procedure for the parameters of two functions, i.e., the maximum size–density line and the self-thinning curve, is presented to predict stand development for fast-growing tropical species. This procedure assumes that the rate of periodic reduction in stand density with increasing quadratic mean diameter on a logarithmic scale (r) will increase inversely proportionally to the distance from the maximum size–density line and consequently equals the slope of the line at distance 0. Under this assumption, the maximum size–density line can be incorporated into the self-thinning curve to form an integrated equation with three parameters: k and m, the slope and constant of the maximum size–density line, and a, the rate of reduction of r of the self-thinning curve. These parameters are estimated simultaneously using measurement data on stand density, quadratic mean diameter, and the corresponding r. This procedure was evaluated by application to two data sets: 186 measurements of Acacia mangium and 95 measurements of Paraserianthes falcataria, for which the parameters k and m have previously been calculated. The parameters estimated using this procedure were in good agreement with previous ones based on the A. mangium data set, and the differences found for the P. falcataria data set were also small, within the error variances. Therefore, it is concluded that the proposed procedure would give almost the same estimates from a single calculation step as the previous procedure that required two separate calculation steps.     

Morphological analysis of viral communities in the floodwater of a Japanese paddy field

Capsid size distributions of viral communities in the floodwater of a Japanese paddy field under a long-term fertilizer trial were surveyed during the rice cultivation period by using transmission electron microscopy. The capsid size distributions were monophasic, and the median values fell within the range of 50-70 nm. The quartile intervals were narrow from either 40-50 nm or 50-60 nm to either 60-70 nm or 70-80 nm for most samples. There was no clear seasonal variation in the capsid size distribution of viral communities. The difference in size distributions among different fertilizer plots was also not found. Viral communities in the floodwater were predominated by isometric icosahedral forms. Viruses with octahedral capsids and elongated ones were rare and sporadic in the floodwater.     

Peripheral neuroblastoma in a young labrador retriever

A 2-year-old Labrador Retriever developed atrophy of the right temporal muscle, subsequently showed generalized seizure and died 2 months after the clinical onset. Postmortem examination revealed the tumor masses in the right mandibulopharyngeal area, nasopharynx and intracranial space. Histopathologically, these tumor masses were composed of small round neoplastic cells and neuropil-like stroma separated by fibrovascular septa. In the neoplastic masses, small neoplastic cells with round to oval hyperchromatic nuclei and scanty cytoplasm predominated, and angulated neoplastic cells with larger nuclei and moderate cytoplasm were scattered. Immunohistochemically, neoplastic cells were positive for neuron specific enorase, neurofilament protein, chromogranin A, synaptophysin and tyrosine hydroxylase. Based on these findings, this case was diagnosed as peripheral neuroblastoma, presumably originated from the sympathetic ganglion, maybe right craninal cervical ganglion.     

A comparative pathological study on canine necrotizing meningoencephalitis and granulomatous meningoencephalomyelitis

Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the cerebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.