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.     

构建全细胞生物传感器测定农田土壤中有机磷农药甲基对硫磷含量

土壤中污染物的生物有效性评估对于准确评价环境污染风险至关重要,而全细胞生物传感器是此类评估的重要工具之一。本研究旨在使用新型全细胞生物传感器建立土壤中甲基对硫磷(methyl parathion,MP)的检测方法。首先,使用筛选出的甲基对硫磷水解酶基因(methyl parathion degrading gene,mpd)和pUC19质粒骨架以及已有的特异性诱导元件pobR为材料,构建全细胞生物传感器。然后,以96孔的酶标板为载体和以5种全细胞生物传感器为指示细胞,建立了土壤提取液样品中甲基对硫磷的分析方法,并应用于实际测试和田间土壤样品中甲基对硫磷的检测。以检测性能的最佳大肠杆菌(Escherichia coli)DH5α/pMP-AmilCP为例,其检测限为6.21−6.66μg/L,线性范围为10−10000μg/L。E.coli DH5α/pMP-RFP和E.coli DH5α/pMP-AmilCP的方法用于分析土壤提取液样品中甲基对硫磷的浓度,具有较好的检测性能。这种全细胞生物传感器方法有助于快速评估土壤中甲基对硫磷的生物有效性强弱,从而有效判断有机磷农药甲基对硫磷对土壤的污染风险。     

聚对苯二甲酸乙二醇酯水解酶检测方法的研究进展

聚对苯二甲酸乙二醇酯(polyethylene terephthalate,PET)是应用最广泛的合成聚酯之一。由于PET不易降解,在环境中积累,对陆地、水生生态系统以及人类健康构成严重威胁。基于生物酶催化的生物降解策略为PET回收利用提供了一种绿色途径,在过去20年间,已发现了多种PET水解酶,并通过蛋白质工程等手段来改善这些酶的降解性能,但是目前仍未找到适合大规模工业应用的PET水解酶。利用传统的检测方法筛选PET水解酶是一个缓慢而复杂的过程。为了促进PET酶法回收的工业化应用,需要研发高效的检测方法。近年来,研究人员开发了多种表征PET水解酶的分析方法。本文总结了可用于筛选PET水解酶的检测方法,如高效液相色谱法、紫外吸光度法和荧光激活液滴分选法等,并对其在筛选PET水解酶的应用方面进行了展望。     

Stereoselective HPLC bioanalysis of atenolol enantiomers in plasma: Application to a comparative human pharmacokinetic study

An enantioselective HPLC bioassay has been developed relying on extraction of (R)- and (S)-atenolol from alkalinized plasma or serum (pH > 12) into dichloromethane containing 5% (v/v) 1-butanol followed by an achiral derivatization of the drug with phosgene leading to (R)- and (S)-oxazolidine-2-one derivatives. Under these conditions there was quantitative conversion of the acetamido group to the corresponding nitrile. These stable derivatives were separated on a (R,R)-diaminocylohexane-dinitrobenzoyl chiral stationary phase [(R,R)-DACH-DNB] using dichloromethane/methanol 98/2 as mobile phase. Determination limits of 0.5 ng for (R)- and 0.6 ng for (S)-atenolol could be achieved using fluorimetric detection. The assay was applied to a human pharmacokinetic study which was performed in a randomized cross-over, double-blind fashion in 12 healthy volunteers, administering single oral doses of 100 mg (R,S)-, 50 mg (R)-, and 50 mg (S)-atenolol AUC_0–24 and C_max values of (R)-atenolol were slightly but significant higher than those of (S)-atenolol. The R/S ratios were 1.09 for AUC(R)/AUC(S) and 1.03 for C_max (R)/C_max(S) (P < 0.01) respectively after administration of the racemic drug. However, there were no differences between AUC, C_max, and t_½ values of each enantiomer, whether they were administered as single enantiometers or in the form of its racemic mixture. © 1993 Wiley-Liss, Inc.     

Bird carcass detection from integrated trials at multiple wind farms

It is often necessary to estimate the number of wind turbine collision fatalities to assess impacts to birds following construction of wind farms. Detection of bird carcasses at wind turbines in the field is affected by carcass persistence and searcher detection rate. Integrated detection trials, which integrate carcass persistence and searcher detection trials into the periodic fatality search, have been proposed as an effective method for estimating these parameters. The purpose of our study was to test whether and how environmental factors affect integrated detection trial outcomes at multiple wind farms. We conducted this study at 10 wind farms in various environments of Japan. Binary data on trial outcomes in open versus forested areas served as our response variable in a generalized additive mixed model informed by days into trial, carcass body mass, season, whether snow covered the ground, and precipitation. For both ground cover types, days into trial and body mass were included in all the top models, suggesting that these factors most influenced bird carcass detection probability in integrated trials. The best model in open areas included days into trial, body mass, snow, and precipitation, and the best model in forested areas included days into trial, body mass, snow, precipitation, and season. Values of area under the curve indicated high accuracy of the best model for both ground cover types. The survey design needs to be appropriate to the size of the target species and to the environment in which the impacts will occur, such as the site's seasonality, its ground cover, and whether snow will cover the ground. Frequency of post-construction fatality monitoring should also be set cautiously, especially at wind farms located on small-bird migration routes, at wind farms in open areas, in areas with snow-covered ground in winter, or in forested areas during spring and summer because detection probabilities decline fastest under such conditions.     

QUALITATIVE ANALYSIS OF BIOECOLOGY DIFFERENTIAL SYSTEM

In this paper, the author studies the quartic bioecology differential system:Here n and q are positive constants, l、m and p are constants. The author also proves some theorems of existence and uniqueness of limit cycles of this differential system.     

Aptamer-functionalized quantum dots as theranostic nanotools against cancer and bacterial infections: A comprehensive overview of recent trends

Aptamers (Apts) are synthetic nucleic acid ligands that can be engineered to target various molecules, including amino acids, proteins, and pharmaceuticals. Through a series of adsorption, recovery, and amplification steps, Apts are extracted from combinatorial libraries of synthesized nucleic acids. Using aptasensors in bioanalysis and biomedicine can be improved by combining them with nanomaterials. Moreover, Apt-associated nanomaterials, including liposomes, polymeric, dendrimers, carbon nanomaterials, silica, nanorods, magnetic NPs, and quantum dots (QDs), have been widely used as promising nanotools in biomedicine. Following surface modifications and conjugation with appropriate functional groups, these nanomaterials can be successfully used in aptasensing. Advanced biological assays can use Apts immobilized on QD surfaces through physical interaction and chemical bonding. Accordingly, modern QD aptasensing platforms rely on interactions between QDs, Apts, and targets to detect them. QD-Apt conjugates can be used to directly detect prostate, ovarian, colorectal, and lung cancers or simultaneously detect biomarkers associated with these malignancies. Tenascin-C, mucin 1, prostate-specific antigen, prostate-specific membrane antigen, nucleolin, growth factors, and exosomes are among the cancer biomarkers that can be sensitively detected using such bioconjugates. Furthermore, Apt-conjugated QDs have shown great potential for controlling bacterial infections such as Bacillus thuringiensis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Campylobacter jejuni, Staphylococcus aureus, and Salmonella typhimurium. This comprehensive review discusses recent advancements in the design of QD-Apt bioconjugates and their applications in cancer and bacterial theranostics.     

山东省假性肥大型肌营养不良的RFLP分析 Ⅰ．可疑携带者的基因型确定

本文选用10个DMD基因内部和桥探针,对山东省9个地区的21个DMD／BMD家系的173名成员进行RFLP分析,其中可疑携带者55人,多数家系应用1－3个探针,有基因重组家庭选用4－5个探针,便可完成多态分析,RFLP分析可以确定85．45％的可疑携带者（≥95％可信限）,即13人确定为携带者,30人排除携带者,另有4人风险大幅提高,通过这些探针的群体多态检测和不同家庭结构和类型的应用分析,我们提出了在中国人群中DMD／SMD基因诊断的基本程序。