A Nanoporous Alumina Membrane Based Electrochemical Biosensor for Histamine Determination with Biofunctionalized Magnetic Nanoparticles Concentration and Signal Amplification.

Histamine is an indicator of food quality and indispensable in the efficient functioning of various physiological systems. Rapid and sensitive determination of histamine is urgently needed in food analysis and clinical diagnostics. Traditional histamine detection methods require qualified personnel, need complex operation processes, and are time-consuming. In this study, a biofunctionalized nanoporous alumina membrane based electrochemical biosensor with magnetic nanoparticles (MNPs) concentration and signal amplification was developed for histamine determination. Nanoporous alumina membranes were modified by anti-histamine antibody and integrated into polydimethylsiloxane (PDMS) chambers. The specific antibody modified MNPs were used to concentrate histamine from samples and transferred to the antibody modified nanoporous membrane. The MNPs conjugated to histamine were captured in the nanopores via specific reaction between histamine and anti-histamine antibody, resulting in a blocking effect that was amplified by MNPs in the nanopores. The blockage signals could be measured by electrochemical impedance spectroscopy across the nanoporous alumina membrane. The sensing platform had great sensitivity and the limit of detection (LOD) reached as low as 3 nM. This biosensor could be successfully applied for histamine determination in saury that was stored in frozen conditions for different hours, presenting a potentially novel, sensitive, and specific sensing system for food quality assessment and safety support.

Description of three new species of Benedictus (Coleoptera, Chrysomelidae, Galerucinae, Alticini) from China, with comments on their biology and modified ethanol traps for collecting flea beetles.

The diversity and biology of the moss and leaf litter-inhabiting flea beetles are still poorly known. In this study, three new species of Benedictus are described from China: Benedictusfuanensis Ruan & Konstantinov, sp. nov., Benedictusquadrimaculatus Ruan & Konstantinov, sp. nov., and Benedictuswangi Ruan & Konstantinov, sp. nov. Comments on their biology are given. Benedictusquadrimaculatus has a highly unusual morphological feature not reported before in flea beetles: black spots on the abdominal tergites that are visible through the elytra. Traditional and modified ethanol traps were tested and proven useful for collecting leaf litter- and moss-inhabiting flea beetles. Based on our tests, eight traps could collect one specimen each day in the testing sites in Fujian Province; three traps could collect one specimen each day in the testing sites in Guangdong Province.

Eco-friendly bio-encapsulation from sodium alginate-trehalose-kaolin and its performance evaluation in improving plant growth under salt or/and drought conditions.

Plant growth-promoting bacterium plays a significant role in improving plant tolerance to abiotic stresses. However, there are low survival and poor effect in field application, especially in unfavorable environments. Our previous study suggested that encapsulation of Bacillus pumilus G5 from polyvinyl alcohol­sodium alginate could improve plant growth and soil fertility under drought and salt soil conditions. However, in the G5 microbeads, the polyvinyl alcohol could not be degraded after entering the soil, and the loss of viable bacteria was severe during the drying process. Achieving a more eco-friendly and efficient formulation based on biodegradable polymers can have significant effects on increasing the quantity and quality of agricultural products. Herein, G5 has immobilized in the composite wall of sodium alginate-trehalose-kaolin microbeads and then evaluated the performance, and applied on the Pharbitis nil under salt or/and drought stress by pot experiment. A 2 % sodium alginate, 1 % trehalose, and 1 % kaolin formulation for the coating films resulted in optimal G5 microbeads embedding efficiency, viable bacteria, degradation rate, and sustained release. Also, the G5 microbeads exhibited longer storage life than that of the G5 suspension. Scanning electron microscopy revealed that the G5 microcapsules had a near-spherical structure with a particle size of around 1000 µm forming a continuous dense composite wall membrane with obvious protrusions and folds on the surface, which facilitated the release of the G5 strain. The interior of the G5 capsule was rough and suitable for bacterial attachment. Infrared spectroscopy showed that the G5 microcapsules are a simple physical mixture with no chemical reaction between the excipients, making the G5 microcapsules chemically stable. The inclusion of the G5 microcapsules considerably induced Pharbitis nil seedlings growth and biomass under drought and/or salt stress. In the rhizosphere soil of Pharbitis nil, the G5 microcapsules increased the total cultivable bacteria population, the activities of invertase, urease, phosphatase, and catalase, and the contents of available nitrogen and available phosphorus. We concluded that a suitable formulation by bio-encapsulation with eco-friendly excipients for alleviating drought and/or salt stress in plants will be advantageous in sustainable agriculture.

Encapsulation of Bacillus pumilus G5 from polyvinyl alcohol­sodium alginate (PVA-SA) and its implications in improving plant growth and soil fertility under drought and salt soil conditions.

Drought and salt stresses adversely affect the growth and yield of plants in agricultural production. Bacillus pumilus, an important plant growth-promoting bacterium, play a significant role in improving plant tolerance to abiotic stresses. In this study, B. pumilus G5 were immobilized in polyvinyl alcohol­sodium alginate (PVA-SA) microbeads and then applied on the Pharbitis nil under drought and salt stresses by pot experiment. Orthogonal array experiments showed that the optimal immobilization conditions of PVA-SA immobilized G5 microbeads were adsorbent 6.0%, PVA: SA 1:1 (3.0%), CaCl2 4.0%, and bacterium: embedding agent (PVA-SA) 3:4; And the G5 microbeads produced at the optimal condition exhibited better cultivable bacteria count, encapsulation rate, expansion rate and mechanical strength. Pot experiment showed that G5 microbeads significantly increased the length and diameter of root and stem, and dry weight of P. nil during experimental stage under drought and salt stress. G5 microbeads also increased the total cultivable bacteria population, the activities of invertase (INV), urease (URE), phosphatase (PHO) and catalase (CAT), and the contents of available nitrogen (AN) and available phosphorus (AP) in the rhizosphere soil of P. nil. Therefore, our study obtained the optimal process of G5 microbeads, and confirmed its effect on improved plant growth and soil chemical and biological properties of P. nil. Thus it can be used as sustainable tool for eco-friendly bio-inoculants at salinity soil within arid and semi-arid areas.

Two new species and new records of Otocepheidae (Acari, Oribatida) from Yunnan, Southwest China.

This work includes taxonomic data on four species of oribatid mites of the family Otocepheidae from Yunnan, China. Two new species of the genera Basiceramerus and Eurostocepheus are described, respectively. Basiceramerusovatus sp. nov. differs from B.bangladeshensis Corpuz-Raros & Gruèzo, 2008 by the wavy marginalis passing the base of the adanal setae, prodorsal condyles well separated from median ones, a ventral ridge present, and the anal plate foveolate; it differs from B.igorotus Corpuz-Raros & Gruèzo, 2011 from Vietnam by the wavy marginalis passing the base of the adanal setae, a connected tutorium and lamelliform expansion, a ventral ridge present, a smooth genital plate, and seta an 2 located close to the median margin of the anal opening; it differs from B.igorotus from the Philippines by the lamellar setae inserted behind the tip of the lamella, separated prodorsal condyles, lyrifissure im posterior to gla, genital plate smooth, anal plate foveolate, and the wavy marginalis passing the base of the adanal setae. Eurostocepheus (Eurostocepheus) sinutussp. nov. differs from other known species of this genus by having a ventral groove between the genital aperture and the ventral ridge, eight pairs of notogastral setae, and distinctly shorter and thinner notogastral setae p 1, p 2, p 3, h 3. Eurostocepheus (Eurostocepheus) aquilinus Aoki, 1965 and E. (E.) mahunkai Mondal & Kundu, 1999 are reported for the first time from China.

Three new species of the subgenus Otocepheus (Acrotocepheus) (Acari, Oribatida, Otocepheidae) from China.

Three new species of subgenus Otocepheus (Acrotocepheus): O. (A.) digitatussp. nov., O. (A.) multigranulatussp. nov., and O. (A.) occultatussp. nov. are proposed and described based on adult material collected from China, and O. (A.) duplicornutus Aoki, 1965 is reported in China for the first time. A key to Chinese species of the subgenus Acrotocepheus is provided.

Taxonomic study on the genus Fissicepheus (Acari: Oribatida: Otocepheidae) from China.

Four new species of the genus Fissicepheus Balogh Mahunka, 1967 from China are described on the basis of adults: Fissicepheus (Fissicepheus) aokii sp. nov., types from Shanxi Province, F. (F.) combicondylus sp. nov., from Guangdong Province, F. (F.) confragosus sp. nov., from Sichuan Province, and F. wangae sp. nov. from Beijing City. A revised generic diagnosis and a key to the 26 known species worldwide of Fissicepheus are provided. Compared with the diagnosis of the subgenus F. (Psammocepheus) Aoki, 1970, F. (P.) haradai Choi, 1986 is moved to the nominotypical subgenus: F. (F.) haradai Choi, 1986.

Nitrogen-doped carbon quantum dots as fluorescent probe for "off-on" detection of mercury ions, l-cysteine and iodide ions.

The application of fluorescent nanoparticles to the detection of inorganic ions and organic compounds has been attracted wide attention recently. In this paper, an "off-on" method for highly sensitive and selective detection of Hg2+ and l-cysteine (l-Cys) or Hg2+ and I- using home-made nitrogen-doped carbon quantum dots (N-CQDs) as fluorescent probe was reported. The N-CQDs with a fluorescence quantum yield of 42.2% were prepared using tartaric acid, citric acid and ethanediamine as the precursors in the oleic acid media. The fluorescence of the obtained N-CQDs could be quenched selectively and sensitively by the addition of Hg2+ (turn-off) with a detection limit of 83.5nM. When l-Cys or I- was added into the N-CQDs-Hg2+ system, the fluorescence was recovered effectively (turn-on). This process could be used to the detection of l-Cys or I- with a detection limit of 45.8 and 92.3nM, respectively.