The impact of engineered nanomaterials on the environment: Release mechanism, toxicity, transformation, and remediation.

The presence and longevity of nanomaterials in the ecosystem, as well as their properties, account for environmental toxicity. When nanomaterials in terrestrial and aquatic systems are exposed to the prevailing environmental conditions, they undergo various transformations such as dissociation, dissolution, and aggregation, which affects the food chain. The toxicity of nanomaterials is influenced by a variety of factors, including environmental factors and its physico-chemical characteristics. Bioaccumulation, biotransformation, and biomagnification are the mechanisms that have been identified for determining the fate of nanomaterials. The route taken by nanomaterials to reach living cells provides us with information about their toxicity profile. This review discusses the recent advances in the transport, transformation, and fate of nanomaterials after they are released into the environment. The review also discusses how nanoparticles affect lower trophic organisms through direct contact, the impact of nanoparticles on higher trophic organisms, and the possible options for remediation.

Genomic insights of Vibrio harveyi RT-6 strain, from infected "Whiteleg shrimp" (Litopenaeus vannamei) using Illumina platform.

The pathogenicity of "Vibriosis" in shrimps imposes prominent menace to the sustainable growth of mariculture economy. Often the disease outbreak is associated speciously with Vibrio harveyi and its closely related species. The present study investigated the complete genome of the strain V. harveyi RT-6 to explore the molecular mechanism of pathogenesis. The genome of V. harveyi possesses a single chromosome of 6,374,398 bp in size, G + C content (44.7%) and 5730 protein coding genes. The reads of 1.3 Gb were retained from Illumina Hiseq 2500 sequencing method, assembled into 5912 predicted genes, 114 tRNAs genes, and 11 rRNAs genes. Unigenes were annotated by matching against Clusters of Orthologous Groups of proteins (COG)-5730, Gene ontology (GO)-1088, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases-3401. Furthermore, 13 insertion sequences-(IS), virulence factors and prophage regions were also identified. A total of 94 pathogenic genes and 36 virulence factor genes were mainly identified using Virulence Factors Database (VFDB). Out of the 36 virulence factors, 23 genes responsible for encoding flagella-based motility protein were exclusively predicted to take part in pathogenic mechanism. The Whole Genome Sequencing (WGS) of the strain RT-6 (accession number: SRR5410471) highlighted the underlying genes and specifically accountable functional genes that were responsible for pathogenic infections in shrimps.

De novo assembly and annotation of the whole genomic analysis of Vibrio campbellii RT-1 strain, from infected shrimp: Litopenaeus vannamei.

OBJECTIVES: This study aimed to sequence the whole genome of Vibrio campbellii RT-1 strain. METHODS: V. campbellii strain was isolated from an infected shrimp, Litopenaeus vannamei collected from aquaculture ponds, India (12.1899° N, 79.9249° E). The whole genome sequencing (WGS) was performed using the Illumina Hiseq 2500 platform and assembled de novo using SPAdes and Velvet optimiser. Furthermore, the gene prediction and annotation were performed by a rapid prokaryotic genome tool-Prokka. RESULTS: The genome of V. campbellii RT-1 strain has one circular chromosome with 6327218 bp long. V. campbellii RT-1 strain contains 5787 predicted genes with an average of 45% GC content. A total of 86 known genes associated with pathogenicity were identified and 28 genes were found to be responsible for virulence factors. Furthermore, 1112 unigenes were subjected to Gene Ontology (GO) terms, and 4895 predicted proteins were annotated with Clusters of orthologous (COGs) functional groups. CONCLUSIONS: The phylogenetic position of V. campbellii RT-1 strain was established through whole genome sequencing and genomic tools which provides a strong platform to further study on genomic alterations and phenotype of V. campbellii.

Ultrasonic-assisted green synthesis of flower like silver nanocolloids using marine sponge extract and its effect on oral biofilm bacteria and oral cancer cell lines.

The knowhow followed for synthesis, characterization and application of nanomaterials has become an important branch of nanoscience. The use of marine sponges for the synthesis of metal nanoparticles is still in the budding level of current nanobiotechnology. This paper reports a single step one pot biosynthesis utilizing marine sponge (Haliclona exigua) extract as a reducing agent by means of a conventional ultrasonic bath on the formation and growth of flower like silver nanocolloids. These silver nanocolloids were characterized through UV visible spectroscopy, High Resolution Transmission Electron Microscope, Fourier Transform Infrared spectroscopy and X-ray Diffractometer. Further, antibacterial activity and antiproliferative activity were done against oral biofilm bacteria and oral cancer cell lines for the biosynthesized flower like silver nanocolloids. Water soluble organic amines were responsible for the syntheses of nanomaterials which have a size range from 100 to 120 nm. An average size of 9.1 mm zone of inhibition was recorded with 10.0 µg of silver nanocolloids against oral biofilm bacteria. The estimated half maximal inhibitory concentration value for flower like silver nanocolloids was 0.6 µg/ml for oral cancer cell lines.

Physiological and biochemical response in green mussel Perna viridis subjected to continuous chlorination: Perspective on cooling water discharge criteria.

Heavy infestation by Perna viridis has been observed in the sub-seabed seawater intake tunnel and CWS of a tropical coastal power station in-spite of continuous low dose chlorination regime (0.2 ± 0.1 mg L-1) (CLDC), indicating periodical settlement and growth. Continuous arrival of mussels (colonized in the sub seabed tunnel intake section) at the pump house indicated that the mussels were able to tolerate and survive in a chlorinated environment, for varying time periods and were dislodged when they become weak and subsequent death, leading to flushing out of the system. In the present study, effect of continuous chlorination [0.2 mg L-1 (in-plant use); 0.5 mg L-1 (shock dose) & 1.0 mg L-1 (high levels)] was evaluated on mussels to assess; (a) time taken for mortality, (b) action of chlorine on physiological, genetic, metabolic and neuronal processes. 100% mortality of mussels was observed after 15 (0.2 mg L-1); 9 (0.5 mg L-1) and 6 days (1.0 mg L-1) respectively. Extended valve closure due to chlorination resulted in stress, impairing the respiratory and feeding behavior leading to deterioration in mussel health. Pseudofaeces excretion reduced to 68% (0.2 mg L-1); 10% (0.5 mg L-1) and 89% (1.0 mg L-1) compared to controls. Genotoxicity was observed with increase in % tail DNA fraction in all treatments such as 86% (0.2 mg L-1); 76% (0.5 mg L-1) and 85% (1.0 mg L-1). Reactive Oxygen Species (ROS) stress biomarkers increased drastically/peaked within the first 3 days of continuous chlorination with subsequent quenching by antioxidant enzymes. Gill produced highest generation of ROS; 38% (0.2 mg L-1); 97% (0.5 mg L-1); 98% (1.0 mg L-1). Additionally, it was shown that 84% (0.2 mg L-1), 72% (0.5 mg L-1), and 80.4% (1.0 mg L-1) of the neurotransmitter acetylcholinesterase activity was inhibited by chlorine at the nerve synapse. The cumulative impact of ROS generation, neuronal toxicity, and disrupted functions weakens the overall health of green mussels resulting in mortality.

Biodeterioration of polyethylene by jellyfish nematocyst protein.

Plastic pollution is one of the major global problems existing now-a-days and has become a cause of serious concern in coastal and marine ecosystems. Increased accumulation of plastics in the aquatic environment by anthropogenic sources results the alteration of the aquatic ecosystem and its functioning. Several variables have an impact on biodegradation, ranging from microbe species to polymer type, physicochemical qualities, and environmental circumstances. The present study was attempted to investigate polyethylene degradation ability of nematocyst protein extracted from the lyophilized nematocyst samples using three different mediums such as distilled water, Phosphate buffered saline (PBS), and seawater. The biodeteriorization potential of nematocyst protein and its interaction with the polyethylene was studied using ATR-IR, phase contrast bright-dark field microscope, and scanning electron microscopic studies. The results uncover the biodeteriorization of polyethylene by jellyfish nematocyst protein without any external physicochemical process and provide evidence for further research.

Optically active organic and inorganic nanomaterials for biological imaging applications: A review.

Recent advancements in the field of nanotechnology have enabled targeted delivery of drug agents in vivo with minimal side effects. The use of nanoparticles for bio-imaging has revolutionized the field of nanomedicine by enabling non-invasive targeting and selective delivery of active drug moieties in vivo. Various inorganic nanomaterials like mesoporous silica nanoparticles, gold nanoparticles, magnetite nanoparticles graphene-based nanomaterials etc., have been created for multimodal therapies with varied multi-imaging modalities. These nanomaterials enable us to overcome the disadvantages of conventional imaging contrast agents (organic dyes) such as lack of stability in vitro and in vivo, high reactivity, low-quantum yield and poor photo stability. Inorganic nanomaterials can be easily fabricated, functionalised and modified as per requirements. Recently, advancements in synthesis techniques, such as the ability to generate molecules and construct supramolecular structures for specific functionalities, have boosted the usage of engineered nanomaterials. Their intrinsic physicochemical properties are unique and they possess excellent biocompatibility. Inorganic nanomaterial research has developed as the most actively booming research fields in biotechnology and biomedicine. Inorganic nanomaterials like gold nanoparticles, magnetic nanoparticles, mesoporous silica nanoparticles, graphene-based nanomaterials and quantum dots have shown excellent use in bioimaging, targeted drug delivery and cancer therapies. Biocompatibility of nanomaterials is an important aspect for the evolution of nanomaterials in the bench to bedside transition. The conduction of thorough and meticulous study for safety and efficacy in well-designed clinical trials is absolutely necessary to determine the functional and structural relationship between the engineered nanomaterial and its toxicity. In this article an attempt is made to throw some light on the current scenario and developments made in the field of nanomaterials in bioimaging.

16S rDNA sequence analysis of culturable marine biofilm forming bacteria from a ship's hull.

Marine bacteria from the hull of a ship in the form of biofilms or microfouling were isolated, cultured, and identified by phylogenetic analysis using 16S rDNA sequences. With an average length of 946 bp, all the 16 sequences were classified using the Ribosomal database project (RDP) and were submitted to the National Center for Biotechnology Information. Phylogenetic analysis using 16S rDNA sequences indicated that the 16 strains belonged to the Firmicutes (IK-MB6 Exiguobacterium aurantiacum, IK-MB7 Exiguobacterium arabatum, IK-MB8 Exiguobacterium arabatum, IK-MB9 Jeotgalibacillus alimentarius, IK-MB10 Bacillus megaterium, IK-MB11 Bacillus pumilus, IK-MB12 Bacillus pumilus, IK-MB13 Bacillus pumilus, IK-MB14 Bacillus megaterium), High GC, Gram-positive bacteria (IK-MB2 Micrococcus luteus, IK-MB5 Micrococcus luteus, IK-MB16 Arthrobacter mysorens), G-Proteobacteria (IK-MB3 Halomonas aquamarina, IK-MB15 Halotalea alkalilenta), CFB group bacteria (IK-MB1 Myroides odoratimimus), and Enterobacteria (IK-MB4 Proteus mirabilis). Among the 16 strains, representatives of the Firmicutes were dominant (56.25%) compared to the high GC, Gram-positive bacteria (18.75%), G-Proteobacteria (12.5%), CFB group bacteria (6.25%), and Enterobacteria (6.25%). Analysis revealed that majority of marine species found in marine biofilm are of anthropogenic origin.

PYRROLO isolated from marine sponge associated bacterium Halobacillus kuroshimensis SNSAB01 - Antifouling study based on molecular docking, diatom adhesion and mussel byssal thread inhibition.

In the present study, an attempt has been made to explore the antifouling potential of bioactive compound isolated from sponge associated bacterium Halobacillus kuroshimensis SNSAB01. The crude extract of SNSAB01 strongly inhibited the growth of fouling bacterial strains with least minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The bioactive compound was characterized through FT-IR, HPLC, GCMS and NMR predicted as 'pyrrolo". From the mass spectral library, structure was elucidated as pyrrolo [1, 2-a] pyrazine-1, 4-dione, hexahydro. The in silico studies provided encouraging docking scores with two interactions by GLN 200 and GLU 304. The extract inhibited 89% diatom adhesion at 350 µg/ml concentration against Amphora sp. An EC50 value of 150 µg/ml for 50% inhibition of byssal thread of Perna viridis and LC50 was found to be 500 µg/ml. The LC50/EC50 ratio of 3.0 indicated nontoxic to nature. The result suggested that pyrrolo[1,2-a]pyrazine-1,4-dione can be used for antifouling coating.

Antibacterial macro molecules from marine organisms.

Marine ecosystem comprises of microorganisms, plants, invertebrates and vertebrates which were rich source of diverse antimicrobial products, which were structurally unique belonging to a known class of macromolecules like peptides, terpenes, alkaloids and proteins, etc. Natural macromolecules from marine ecological niches are a promising source of antibacterial agents against several drug resistant strains of pathogenic microorganisms; whereas rest of the metabolites were derived from marine flora and fauna while some arise from microbes associated with living organisms. >30,000 natural macromolecules have been identified and reported from marine organisms, however only few macromolecules are being explored and validated. The discovery of marine antibacterial macromolecules plays a significant part in the field of drug discovery and biomedical research. Despite the fact that literatures were documented on the antifungal, antiviral, antimalarial and anticancer properties, this review exclusively highlights the different antibacterial natural macromolecules from marine sources like bacteria, fungi, sponge, algae, bryozoans, tunicates, corals, cnidarians, arthropods and echinoderm along with their mode of action.

Silver nanoparticles with anti microfouling effect: a study against marine biofilm forming bacteria.

Marine biofilms are the preliminary entities due to attachment of bacteria on surfaces immersed in seawater and aggregated in a hydrated polymeric matrix. Such biofilms or microfouling play a major role in the succession of marine biofouling which attracts the larvae of barnacles, mussels and other sessile invertebrates. Different approaches have been used to prevent micro and macrofouling on marine industrial settings. Silver nanoparticles are renowned for their influential antimicrobial activity. On this back drop the present work is focused on the effect of biosynthesized silver nanoparticles against marine biofilm forming bacterial species. Aspects such as circular zone of inhibition, quantification of biofilm formation and bacterial growth were assessed for bacterial species isolated from the marine biofilm in the presence and sabsence of silver nanoparticles. The size of the circular zone formation was directly proportional to the concentration of biosynthesized silver nanoparticles that reflected the antimicrobial effect. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The growth of bacteria in the presence and absence of silver nanoparticles concluded the bactericidal ability of the silver nanoparticles. However, further research is required to examine these factors.

Biosynthesis of gold nanoparticles utilizing marine sponge Acanthella elongata (Dendy, 1905).

The growing trend of exploring bacteria, fungi, actinomycetes and plant materials for the biosynthesis of nanoparticles is considered as eco friendly and a green technological approach. In this backdrop the present study reports the synthesis of gold (Au) nanoparticles from gold precursor using the extract derived from the marine sponge, Acanthella elongata (Dendy, 1905) belonging to the primitive phylum Porifera. Water-soluble organics present in the marine sponge extract were mainly responsible for the reduction of gold ions to nano-sized Au particles. The sponge extract added to 10-3 M HAuCl4 aqueous solution at 45°C changed to pinkish ruby red color solution and confirm the bioreduction within 4 h with continuous stirring. UV-visible spectrum of the aqueous medium containing gold nanoparticles showed a peak around 526 nm. High-resolution transmission electron micrographs (HR-TEM) confirmed the monodispersed and spherical shaped with the size ranges from 7 to 20 nm, however a maximum number of particles were in 15 nm diameter. Through Fourier transform infrared spectroscopy (FT-IR) analysis, the reducing agent in the marine sponge extract was identified which is attributed for the biosynthesis of gold colloids. The XRD analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles.