Long-term changes in frequencies ofPythium iwayamai andP. paddicum in upland- and paddy-field soils

The long-term changes in the frequencies ofPythium iwayamai andP. paddicum in upland- and flooded paddy-field soils were compared. The frequencies of both species fell in both soils within the first 6 months after they had been buried. After 36 and 48 months,P. iwayamai showed higher frequency thanP. Paddicum in upland-field soil, whileP. paddicum showed higher frequency thanP. iwayamai in paddy-field soil. These findings indicate respectively higher colonization ability to organic matters ofP. iwayamai in upland-field soil andP. paddicum in paddy-field soil.This study was partly supported by a Grant-in-Aid (no. 63560048) from the Ministry of Education, Science and Culture, Japan.     

细胞培养物中污染支原体的去除

经小鼠体内、体外加用不同的抗菌素处理及克隆的方法处理细胞污染的支原体,三株细胞经两次、一株细胞经三次处理后,经培养法、ＤＮＡ染色法及ＰＣＲ法检查支原体污染均为阴性,并证明对其抗体分泌没有任何影响,不失为一个理想的去除支原体的方法,从而使有重要应用价值的支原体污染细胞的应用成为可能。     

应用重离子束苏制核微孔滤膜除菌除支原体的研究

本文采用苏制核微孔滤膜进行了除菌、除支原体实验研究,核孔膜孔径分别为０．０７、０．１、０．５、０．７及１．５微米,采用的菌种为白色葡萄球菌、链球菌和大肠杆菌,支原体为解脲脲原体,实验结果表明：０．０７及０．１微米的核孔膜可完全滤除细菌及支原体,０．５微米的核孔膜可滤除绝大部分细菌,不能滤除支原体,１．５微米的核孔膜只能滤除少量细菌。     

The Presence of (+)-S-Adenosyl-l-Methionine in the Rat Brain and Its Lack of Effect on Phenylethanolamine N-Methyltransferase Activity

Abstract: (+)-S-Adenosyl- l -methionine [(+)-SAM] was isolated from rat brain and was quantified by HPLC followed by UV spectrophotometric measurements and by ¹H-NMR. Its estimated ratio in brain is 3% of total SAM. Because of its commercial unavailability, (+)-SAM was also prepared from chemically synthesized SAM by separation of the two diastereoisomers on a preparative reverse-phase Nucleosil C8 column. The (+) diastereoisomer thus obtained was then assayed in vitro both as an inhibitor and a substrate of phenylethanolamine N -methyltransferase. Enzymatic activity was measured by HPLC analysis. It was shown that (+)-SAM has no effect on phenylethanolamine N -methyltransferase activity; therefore, it is unlikely that (+)-SAM plays any possible role in regulation of adrenaline synthesis in the brain.     

Comparison of the conserved region in the dnaA gene from three mollicute species

Abstract Polymerase chain reaction was carried out to amplify the conserved region (789 bp in the case of Mycoplasma capricolum ) of the dnaA gene (1350 bp in the case of M. capricolum ) of 15 representatives of the class Mollicutes using degenerate oligonucleotide primers. The dnaA gene fragments were amplified from M. mycoides subsp. capri, Spiroplasma apis and S. citri . The amino acid sequences deduced from the nucleotide sequences of the amplified fragments showed very low similarities to those of the corresponding regions of four walled bacteria. The values of similarity between any two of the three mollicute species were lower than those between any two of the four walled bacteria.     

Object detection by honeybees: Why do they land on edges?

Behavioural experiments using a variety of experimental situations (Figs. 1, 3, 6, 7, 9) were conducted to investigate the visual cues which bees use in the task of object-ground discrimination. The bees' flight and landing behaviour was video-filmed throughout the experiments. The evaluation of the video data shows that bees trained to find a randomly textured figure raised above a similarly textured ground land mainly on the boundaries of the figure, facing its inner surface (Fig. 2a, b). Bees can also be trained to find a hole, i.e. a low texture viewed through a window cut in a raised texture, but these bees are not attracted to the edges of the hole (Fig. 5a, b). Bees trained to a single edge between a low and a raised random texture land at the edge mainly facing the raised side (Table 1). Bees approaching the edge from the high side cross the edge in most cases without landing on it (Table 1). Bees trained to an edge between 2 striped patterns, one raised above the other, again land on the edge facing the raised pattern, regardless of whether the stripes on the 2 patterns run parallel or perpendicular to each other or to the edge (Fig. 8). In this case, the bees acquire range information by flying in oblique directions with respect to the orientation of the stripes (Fig. 10). All of the results suggest that the edge elicits landings when the bee perceives a local increase in the speed of image motion, signalling an abrupt decrease in range. This is corroborated by the results of further experiments in which artificial motion was used to simulate range differences between the two sides of an edge (Table 2). We conclude that image speed is a powerful cue in range discrimination as well as object detection. Dedicated to G. Adrian Horridge on the occasion of his retirement     

Chemotaxis away from thiocyanic and isothiocyanic esters in Pseudomonas aeruginosa

Abstract A novel mycoplasmal species designated as Mycoplasma penetrans has recently been isolated from patients infected with human immunodeficiency virus. The 16S rRNA gene from this mycoplasma was cloned and its nucleotide sequence determined. This sequence was aligned with previously published homologous sequences from several mycoplasmas and with related Gram-positive bacteria and a phylogenetic tree was constructed. The results indicate that M. penetrans belongs to the evolutionary group Pneumoniae.     

Water conditions influence the detectability of Crossodactylus gaudichaudii (Anura,Hylodidae) in streams of the Atlantic Forest

Stream-dwelling amphibians' occurrence, behaviour and reproductive success are strongly influenced by dynamic abiotic factors, for example, water flow and spray. These factors can disproportionately affect these frogs due to their dependency on specific favourable conditions for development and incapacity to disperse from unfavourable environments. We analysed the influence of environmental covariates on the detectability of Crossodactylus gaudichaudii, an amphibian species endemic to streams in the Brazilian Atlantic Forest. We conducted sampling in the streams of the Duas Bocas Biological Reserve, Brazil, and we measured air and water temperature, air humidity and pH of water on each sampling occasion. We estimated the effects of variables on the detectability of the species using single-season occupancy models. Our results indicated that the detectability of the species increases on occasions with higher water temperatures (24–26°C) and lower pH (5.0–5.5). We investigated the influence of these covariates only on the detectability of adult frogs, but it is likely that the physiochemical properties of stream water are more important to aquatic larvae, and hence, the probability of their detection. Given this, further studies should examine the relevance of covariates on the detectability of adult frogs as well as larvae.     

Nanostructured material-based optical and electrochemical detection of amoxicillin antibiotic

The penicillin derivative amoxicillin (AMX) plays an important role in treating various types of infections caused by bacteria. However, excessive use of AMX may have negative health effects. Therefore, it is of utmost importance to detect and quantify the AMX in pharmaceutical drugs, biological fluids, and environmental samples with high sensitivity. Therefore, this review article provides valuable and up-to-date information on nanostructured material-based optical and electrochemical sensors to detect AMX in various biological and chemical samples. The role of using different nanostructured materials on the performance of important optical sensors such as colorimetric sensors, fluorescence sensors, surface-enhanced Raman scattering sensors, chemiluminescence/electroluminescence sensors, optical immunosensors, optical fibre-based sensors, and several important electrochemical sensors based on different electrode types have been discussed. Moreover, nanocomposites, polymer, and MXenes-based electrochemical sensors have also been discussed, in which such materials are being used to further enhance the sensitivity of these sensors. Furthermore, nanocomposite-based photo-electrochemical sensors and the market availability of biosensors including AMX have also been discussed briefly. Finally, the conclusion, challenges, and future perspectives of the above-mentioned sensing techniques for AMX detection are presented.     

Searching by parts: Towards fine-grained image retrieval respecting species correlation

Most of the existing works on fine-grained image categorization and retrieval focus on finding similar images from the same species and often give little importance to inter-species similarities. However, these similarities may carry species correlations such as the same ancestors or similar habits, which are helpful in taxonomy and understanding biological traits. In this paper, we devise a new fine-grained retrieval task that searches for similar instances from different species based on body parts. To this end, we propose a two-step strategy. In the first step, we search for visually similar parts to a query image using a deep convolutional neural network (CNN). To improve the quality of the retrieved candidates, structural cues are introduced into the CNN using a novel part-pooling layer, in which the receptive field of each part is adjusted automatically. In the second step, we re-rank the retrieved candidates to improve the species diversity. We achieve this by formulating a novel ranking function that balances between the similarity of the candidates to the queried parts, while decreasing the similarity to the query species. We provide experiments on the benchmark CUB200 dataset and Columbia Dogs dataset, and demonstrate clear benefits of our schemes.