The environmental fate and behaviour of antifouling paint booster biocides: A review

Antifouling paint booster biocides are a group of organic compounds added to antifouling paints to improve their efficacy. They have become prevalent since the requirement for alternative antifouling paints formulations for small boats (< 25 m). This need followed a ban on the use of triorganotin biocides in antifouling paints for small boats, in the late 1980's. Worldwide, around eighteen compounds are currently used as antifouling biocides, viz. benzmethylamide, chlorothalonil, copper pyrithione, dichlofluanid, diuron, fluorofolpet, Irgarol 1051, Sea‐Nine 211, Mancozeb, Polyphase, pyridine‐triphenyl‐borane, TCMS (2,3,5,6‐tetrachloro‐4‐methylsulfonyl) pyridine, TCMTB [2‐(thiocyanomethylthio)benzothia‐zole], Thiram, tolyfluanid, zinc pyrithione (ZPT), ziram and Zineb. Any booster biocide released into the environment is subjected to a complex set of processes. These processes include transport mechanisms, transformation, degradation, cross media partitioning, and bioaccumulation. This paper reviews the fate and behaviour data currently available in the public domain concerning antifouling paint booster biocides.     

Functional evolution of two subtly different (similar) folds

Background

The function of proteins is a direct consequence of their three-dimensional structure. The structural classification of proteins describes the ways of folding patterns all proteins could adopt. Although, the protein folds were described in many ways the functional properties of individual folds were not studied.

Results

We have analyzed two β-barrel folds generally adopted by small proteins to be looking similar but have different topology. On the basis of the topology they could be divided into two different folds named SH3-fold and OB-fold. There was no sequence homology between any of the proteins considered. The sequence diversity and loop variability was found to be important for various binding functions.

Conclusions

The function of Oligonucleotide/oligosaccharide-binding (OB) fold proteins was restricted to either DNA/RNA binding or sugar binding whereas the Src homology 3 (SH3) domain like proteins bind to a variety of ligands through loop modulations. A question was raised whether the evolution of these two folds was through DNA shuffling.     

Self-assembled PEG monolayer based SPR immunosensor for label-free detection of insulin

A simple and rapid continuous-flow immunosensor based on surface plasmon resonance (SPR) has been developed for detection of insulin as low as 1 ng ml-1 (ppb) with a response time of less than 5 min. At first, a heterobifunctional oligo(ethyleneglycol)-dithiocarboxylic acid derivative (OEG-DCA) containing dithiol and carboxyl end groups was used to functionalize the thin Au-film of SPR chip. Insulin was covalently bound to the Au-thiolate monolayer of OEG-DCA for activating the sensor surface to immunoaffinity interactions. An on-line competitive immunosensing principle is examined for detection of insulin, in which the direct affinity binding of anti-insulin antibody to the insulin on sensor surface is examined in the presence and absence of various concentrations of insulin. Immunoreaction of anti-insulin antibody with the sensor surface was optimized with reference to antibody concentration, sample analysis time and flow-rate to provide the desired detection limit and determination range. With the immunosensor developed, the lowest detectable concentration of insulin is 1 ng ml-1 and the determination range covers a wide concentration of 1-300 ng ml-1. The developed OEG-monolayer based sensor chip exhibited high resistance to non-specific adsorption of proteins, and an uninterrupted highly sensitive detection of insulin from insulin-impregnated serum samples has been demonstrated. After an immunoreaction cycle, active sensor surface was regenerated simply by a brief flow of an acidic buffer (glycine.HCl; pH 2.0) for less than 1 min. A same sensor chip was found reusable for more than 25 cycles without an appreciable change in the original sensor activity.     

Surface plasmon resonance biosensor for dopamine using D3 dopamine receptor as a biorecognition molecule

In modern biomedical technology, development of high performance sensing methods for dopamine (DA) is a critical issue because of its vital role in human metabolism. We report here, a new kind of bioaffinity sensor for DA based on surface plasmon resonance (SPR) using a D(3) dopamine receptor (DA-RC) as a recognition element. A conjugate of DA was synthesized using bovine serum albumin (BSA) protein and was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The biosensor surface was constructed by the immobilization of the DA-BSA conjugate onto an SPR gold surface by physical adsorption. Atomic force microscopy (AFM) investigations revealed that the DA-BSA conjugate was homogeneously distributed over the sensor surface. Specific interaction of the DA-RC with the immobilized DA-BSA conjugate was studied by SPR. Based on the principle of indirect competitive inhibition, the biosensor could detect DA in a linear dynamic range from 85 pg/ml (ppt) to 700 ng/ml (ppb). The biosensor was highly specific for DA and showed no significant interference from potent interferences such as ascorbic acid (AA), uric acid (UA) and other DA analogues viz., 3,4 dihydroxyphenyl acetic acid (DOPAC) and 3-(3,4 dihydroxyphenyl)-alanine (DOPA). The sensor surface displayed a high level of stability during repeated regeneration and affinity reaction cycles. Since this biosensor is simple, effective and is based on utilization of natural receptor, our study presents an encouraging scope for development of portable detection systems for in-vitro and in-vivo measurement of DA in clinical and medical diagnostics.     

Virus isolation and molecular epidemiology of highly pathogenic avian influenza A(H5N8) from an outbreak in free-ranging wild birds,India 2016

We report the molecular epidemiology of highly pathogenic avian influenza (HPAI) virus involved in an outbreak causing death in free-ranging wild birds at Mysore, Karnataka state of India. The virus was typed as HPAI A(H5N8) by conventional and TaqMan probe based real-time PCR assays. Six isolates of HPAI virus were recovered in 9-day-old embryonated chicken eggs. Haemagglutinin gene-based phylogeny of virus isolates showed >?99.9% nucleotide sequence identity with HPAI A(H5N8) isolates from migratory birds and domestic poultry from China and Korea indicating either these wild birds have routed their migration through Korea and/or eastern China or these dead birds must have directly or indirectly contacted with wild birds migrating from Eastern China and/or Korean regions. The study emphasises the role of migratory wild birds in spread of HPAI across the globe.     

Highly sensitive and selective surface plasmon resonance sensor for detection of sub-ppb levels of benzo[a]pyrene by indirect competitive immunoreaction method

A surface plasmon resonance (SPR)-immunosensor for detection of benzo[a]pyrene (BaP) is developed by using a model BaP-hapten compound, BaP-bovine serum albumin conjugate (BaP-BSA), and an anti-BaP-BSA monoclonal antibody. BaP-BSA conjugate is immobilized on a gold thin-film sensor chip by means of simple physical adsorption. The number of BaP-hapten units in BaP-BSA conjugate is estimated to be 28 from the difference in molecular weight (MW) between BaP-BSA conjugate and BSA based on the results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) measurement. Anti-BaP-BSA antibody on contact with the BaP-BSA conjugate immobilized sensor chip causes an increase in the incident angle of the sensor chip. Binding of anti-BaP-BSA antibody with surface-immobilized BaP-BSA conjugate is inhibited by the presence of BaP in analyte solution, because of the inhibition effect of BaP. The SPR immunosensor for BaP functioning with the indirect competitive immunoreaction of anti-BaP-BSA antibody between the analyte (BaP) in testing solution and the BaP-BSA conjugate immobilized on the sensor chip provides a rapid determination (response time: ca. 15 min) of BaP in the concentration range of 0.01-1000 ppb. The antibody anchored to the sensor chip by antigen-antibody binding is removed on treatment with a pepsin solution (pH 2.0) for few minutes. The SPR sensor chip is found to be reusable for more than 20 times with a little decrease (<7%) in the sensor response. Detection of BaP by direct competitive immunoreactions is also carried out by enzyme-linked immunosorbent assay (ELISA). The concentration of BaP could be determined as low as 0.01 ppb and 2 ppb using the SPR sensor and the ELISA method, respectively. The SPR sensor is found to detect BaP selectively in the presence of 2-hydroxybiphenyl (HBP); the incident angle shift of the SPR sensor for BaP is found to be same irrespective to the presence or the absence of a same concentration (as much as 30 ppb) of HBP together.     

Continuous flow immunosensor for highly selective and real-time detection of sub-ppb levels of 2-hydroxybiphenyl by using surface plasmon resonance imaging

A biosensor based on surface plasmon resonance (SPR) is developed for the detection of 2-hydroxybiphenyl (HBP). A monoclonal antibody against HBP (abbreviated hereafter as HBP-mAb) is developed and used for the detection of HBP by competitive SPR-based immunoassay and enzyme linked immunosorbent assay (ELISA) methods. A novel HBP-hapten compound, HBP-bovine serum albumin conjugate (HBP-BSA), derived by binding several HBP units with BSA by an aliphatic chain spacer is used in the development of antibody and for the functionalization of immunoprobes. HBP-BSA linked to the Au surface of the SPR sensor chip undergoes inhibitive immunoreaction with HBP-mAb in the presence of free HBP. The SPR-based immunoassay provides a rapid determination (response time: approximately 20 min) of the concentration of HBP in the range of 0.1-1000 ppb (ng/ml). Regeneration of the sensor chip is gained by treating the antibody-anchored SPR sensor chip with a pepsin solution (100 ppm (microg/ml); pH 2.0) for few minutes. The SPR sensor chip is reusable for the detection of HBP for more than 20 cycles with average loss of 0.35% reactivity per regeneration step. HBP concentration is determined as low as 0.1 and 3 ppb using the SPR sensor and ELISA measurements, respectively. The developed SPR sensor for HBP is free from interference by coexisting benzo[a]pyrene (BaP), 2,4-dichlorophenoxyacetic acid (2,4-D) and benz[a]anthracene; SPR angle shift obtained to the flow of HBP is almost same irrespective to the presence or absence of a same concentration of these carcinogenic polycyclic aromatic hydrocarbons together. The SPR sensor for HBP is proved to be applicable in simultaneous detection of HBP and BaP in parallel with another SPR sensor for BaP.     

Associations of Forest Type,Parasitism and Body Condition of Two European Passerines,Fringilla coelebs and Sylvia atricapilla

Human-induced forest modification can alter parasite-host interactions and might change the persistence of host populations. We captured individuals of two widespread European passerines (Fringilla coelebs and Sylvia atricapilla) in southwestern Germany to disentangle the associations of forest types and parasitism by haemosporidian parasites on the body condition of birds. We compared parasite prevalence and parasite intensity, fluctuating asymmetries, leukocyte numbers, and the heterophil to lymphocyte ratio (H/L-ratio) among individuals from beech, mixed-deciduous and spruce forest stands. Based on the biology of bird species, we expected to find fewer infected individuals in beech or mixed-deciduous than in spruce forest stands. We found the highest parasite prevalence and intensity in beech forests for F. coelebs. Although, we found the highest prevalence in spruce forests for S. atricapilla, the highest intensity was detected in beech forests, partially supporting our hypothesis. Other body condition or health status metrics, such as the heterophil to lymphocyte ratio (H/L-ratio), revealed only slight differences between bird populations inhabiting the three different forest types, with the highest values in spruce for F. coelebs and in mixed-deciduous forests for S. atricapilla. A comparison of parasitized versus non-parasitized individuals suggests that parasite infection increased the immune response of a bird, which was detectable as high H/L-ratio. Higher infections with blood parasites for S. atricapilla in spruce forest indicate that this forest type might be a less suitable habitat than beech and mixed-deciduous forests, whereas beech forests seem to be a suboptimal habitat regarding parasitism for F. coelebs.     

Novel miniature SPR immunosensor equipped with all-in-one multi-microchannel sensor chip for detecting low-molecular-weight analytes

A simple and versatile miniaturized surface plasmon resonance (SPR) immunosensor enabling parallel analysis of multiple analytes or multiple samples of an analyte has been investigated for detection of a low-molecular-weight (lmw) toxin, 2,4-dichlorophenoxyacetic acid (2,4-D). A specially designed multi-microchannel SPR sensor module, integrating an optical-prism coated with an array of thin Au-films, a multi-microchannel plate (eight channels) and a flow-cell together, has been fabricated. The sensing surface was fabricated simply by physical adsorption of a protein conjugate of 2,4-D, and an indirect competitive immunoassay principle has been applied for the quantification of 2,4-D. Multiple 2,4-D samples were analyzed in a single step and a low-detection-limit (LDL) of 0.1 ppb (ng ml(-1)) 2,4-D was established. Competence of the portable SPR immunosensor for selective detection of 2,4-D despite the presence of various structurally resemblant interferents and from river-water samples has been demonstrated. The independent all-in-one sensor module highly favors shelf-storage between multiple determinations, and reusability of a same multi-microchannel flow-module for more than 35 days with intermittent storage (4-8 degrees C) has been confirmed. The LDL of 2,4-D could be enhanced further by introducing a simple avidin-biotin interaction-based sandwich immunoassay, with which the sensor signal multiplied enormously by a factor of ca. 10 and the LDL enhanced to 0.008 ppb. The miniature SPR sensor demonstrated here for simultaneous analysis of multiple samples with reusability and good storage ability is an important consideration for the advancement of biosensor technology.