The incidence of antibacterial activity in marine demospongiae; systematic and geographic considerations

Thirty species of temperate-zone sponges representative of all orders of the Demospongiae have been tested for antibacterial activity. The results indicate the following: that a higher percentage of temperate than tropical species produced active extracts (87% as opposed to 58%); that sponge extracts more frequently inhibited the growth of marine bacteria than they did non-marine bacteria (76.5% compared to 56%); that 46.5% of the extracts tested inhibited growth of Gram-negative bacteria while only 6.5% inhibited growth of Gram-positive bacteria. There is no obvious correlation between incidence of antibacterial activity and latitude of occurrence, systematic group or growth form of the sponge. It is suggested that antibacterial agents produced by sponges may have a role in enhancing the efficiency with which sponges retain bacterial food.     

Antibacterial,antiviral and antioxidant activities of aerial part extracts of Peganum harmala L. grown in Tunisia

Ethyl acetate, chloroform, butanol, and methanol extracts from the aerial part of Peganum harmala were tested for antibacterial, antioxidant, and antiviral activities. The antibacterial activity was evaluated by the determination of minimum inhibitory concentration (MIC) using the solid medium technique. Oxacillin, amoxicillin, ticarcillin, cefotaxim, and amphotericin were used as control agents. The antiviral activity was evaluated against human cytomegalovirus (HCMV) strain AD-169 (ATCC Ref. VR 538) and Coxsackie B virus type 3 (CoxB-3) using a cytopathic effect (CPE) reduction assay. The antioxidant activity was evaluated using two tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging and ammonium thiocyanate methods. Among tested extracts; the chloroform extract displayed a higher antibacterial activity against Gram-positive than Gram-negative bacteria. The butanol extract demonstrated the highest antioxidant activity. The methanol extract showed significant antiviral activity against CoxB-3 virus. The chloroform extract may be an important source of bactericidal compounds against Gram-positive bacteria.     

Relationships of biological and taxonomic characteristics to chemically mediated bioactivity in Mediterranean littoral sponges

The aim of this study was to detect relationships of bioactive properties (antibacterial, antifungal, antiviral antimitotic and cytotoxic activities) of Mediterranean littoral sponges with some of their biological characteristics (growth habits, presence of symbiotic or epibiotic organisms, structural defences) and their systematic position. Antimitotic and cytotoxic activities were present in 80.6% and 73.6% of the species respectively, 42.2% of the species showed antibacterial activity, 29.8% were antiviral and 22.5% were antifungal. Only antiviral and antifungal activities were significantly dependent on taxonomical order, being especially important in the Axinellida. Antiviral, antifungal and antibacterial activities predominated in erect forms, and were poorly represented in encrusting forms, which, however, included a higher percentage of cytotoxic and antimitotic species. Nevertheless, only antiviral activity was significantly related to growth habit. All types of activities were significantly dependent on sponge skeletal features: the highest percentages of species with cytotoxic activity were found among horny and siliceous sponges. Also, antiviral and antibacterial activities were better represented in horny sponges. Antibacterial, antifungal and antiviral activities were dependent on the presence/absence of epibionts and seemed to be more efficient as antifouling defences than antimitotic and cytotoxic activities. Only cytotoxic activity was significantly more wide-spread in species harbouring cyanophyceae. Correspondence analysis revealed that cytotoxic and antimitotic activities were both related to encrusting forms, a siliceous skeleton, occasional epibiosis and the presence of cyanophyceae. Antifungal, antibacterial and antiviral activities were mainly related to erect or globular form, siliceous and horny skeleton and habitual (species-specific) epibiosis.     

Bioactive potential of seagrass bacteria against human bacterial pathogens

Study of marine organisms for their bioactive potential, being an important part of marine ecosystem, has picked up the rhythm in recent years with the growing recognition of their importance in human life. Investigation was carried out to isolate 32 strains of endo and epiphytic bacteria in 2 seagrass species viz., Syringodium isoetifolium and Cymodocea serrulata. Morphologically different bacterial strains were tested against 5 antibiotic resistant human bacterial pathogens, of which 10 associated bacteria shown inhibitory activity against one or more bacterial pathogens. Minimum inhibitory concentration (MIC) and Minimum bacterial concentration (MBC) determination with extracellular bioactive compounds from the associated bacteria reveals that, the strain ENC 5 showed inhibitory activity against all the bacterial pathogens with the maximum sensitivity against Pseudomonas aeruginosa at the MIC value of 500 microg ml(-1).     

Biosynthesis and effects of copper nanoparticles on plants

Copper nanoparticles have improved properties compared to the bulk copper material. Copper nanoparticles indeed find applications in gas sensors, heat transfer fluids, catalysis, solar energy and batteries. Antibacterial and antifungal activities of copper nanoparticles find applications in the agriculture and healthcare sectors. Nonetheless, careless use of copper nanoparticles may cause environmental pollution and health effects. Here we review the biosynthesis of copper nanoparticles using plant materials, named phytosynthesis, and micro-organisms. We also discuss the effect of copper nanoparticles on crops and pathogenic micro-organisms. Copper nanoparticles varying in sizes from 5 to 295 nm have been synthesized using leaf extracts and latex from plants, and using bacteria and fungi. Biosynthesized copper nanoparticles show good antimicrobial activity inhibiting the growth of pathogenic bacteria and pathogenic fungi. Copper nanoparticles enhance the germination and growth of some plants at lower concentrations, whereas high concentrations result in retarded growth.     

Antifungal activity of volatile metabolites emitted by mycelial cultures of saprophytic fungi

The antifungal activity of molecular identified Chilean saprobiontic fungi, Trichoderma viride, Schizophyllum commune and Trametes versicolor, on the fungal plant pathogens Botrytis cinerea and Fusarium oxysporum, and the saprotrophic mould Mucor miehei was investigated using two types of inhibition bioassay: (1) bi-compartmented Petri dishes and (2) two Erlenmeyer flasks connected by their upper parts. The chemical composition of volatile organic compounds (VOCs) released by saprobiontic fungi was also investigated using headspace solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC-MS) analysis. Of the saprobiontic fungi evaluated, one isolate of S. commune showed the highest inhibitory activity against B. cinerea and M. miehei, 86.0±5.4 and 99.5±0.5% respectively. The volatile profiles of fungal isolates were shown to contain a different class of compounds. The major components in the headspace of mycelial cultures were 6-pentyl-α -pyrone (T. viride), ethanol and β -bisabolol (S. commune), and a sesquiterpene alcohol (Tr. versicolor). This is the first study reported on the release of VOCs by Chilean native fungi and their antifungal activity wrt. plant pathogenic fungi.     

Environmental contamination using accumulation of metals in marine sponge,Sigmadocia fibulata inhabiting the coastal waters of Gulf of Mannar,India

Coastal marine ecosystems in many parts of the world are under unrelenting stress caused by urban development, pollutants and other ecological impacts such as building of infrastructure, land reclamation for port and industrial development, habitat modification, tourism and recreational activities. The present work is a first extensive field study using the marine sponge, Sigmadocia fibulata as a bioindicator to detect metal pollution between inshore and offshore environment of the ‘Gulf of Mannar’, India. Samples of S. fibulata were collected from different places of inshore (0.1–0.5?km) and offshore (3–5?kms) locations. Metal concentrations in water and bioaccumulation in sponges were determined by ICP-MS (Inductively coupled plasma-mass spectrometry). Enrichment of metal contamination was more in the inshore, when compared to offshore environment. Higher concentrations of metals Fe, Al, Ni, Mn, Cu, Cr, Co, Ba, Zn, V, Pb and Cd in inshore waters (3–6.4 times than offshore) may be due to the discharge of monsoonal rains, carrying a discharge of industrial and agricultural wastes and sewage directly into the coast. This is substantiated by a highly significant positive correlation between concentrations of metals in the water and accumulation in sponges. The bioaccumulation of metals in sponge tissue were in order of Fe?>?Al?>?Ni?>?Mn?>?Cu?> Cr?>?Co?>?Ba?>?Zn?>?V?>?Cd?>?Pb in both the inshore and offshore regions. Apparently, the macromolecule composition (sugars, proteins and lipids) was significantly reduced by the accumulation of metals in inshore sponges. The current findings indicated that the frequent monitoring is necessary to assess the eco-health of the marine environment by choosing bio-indicator species like S. fibulata, which provide accurate, reliable measurements of environmental quality.     

Active pharmaceutical ingredient (api) from an estuarine fungus, Microdochium nivale (Fr.)

Various marine habitats sustain variety of bio-sources of ecological and biotech potentials. Pharmaceutical potential compound Cyclosporine A was reported from marine fungus Microdochium nivale associated with Porteresia coarctata, a marine salt marsh grass from mangrove environment distributed along the Central West Coast (CWC) of India. This study involves association of M. nivale with P. coarctata plant, fermentation conditions, purification of Cyclosporine A, chemical characterization etc. Its antifungal inhibition and MIC (Minimum inhibitory concentration) against Aspergillus strains (A. niger, A. japonicus, A. fresenii), yeasts and dermatophytes (Candida sp., Cryptococcus neoformans, Trichophyton mentagrophytes, T. tonsurans, T. violaceum, Microsporium gypsum and Fusarium sp.) were evaluated. However, the MIC against A. japonicus, C. neoformans, Candida sp. and T. tonsurans were confirmed to be as low as 12.5-25 mg disc(-1). The antifungal properties of Cyclosporine A against Aspergillus species, yeast and dermatophytes revealed that CyclosporineAwould be a potential compound for life threatening diseases caused by above fungi in both human and animals. Furthermore, we have reported herewith another source of Cyclosporin Aderived from filamentous fungus, M. nivale. occurring in marine environment.     

Microbial diversity in the marine sponge Aplysina cavernicola (formerly Verongia cavernicola) analyzed by fluorescence in situ hybridization (FISH)

We have employed electronmicroscopical methods (SEM, TEM) to document the microbial community associated with the marine sponge Aplysina cavernicola (formerly Verongia cavernicola, class Demospongiae). Five dominant bacterial types were identified, three of which resemble the morphotypes originally described by Vacelet (1975). One bacterial type possesses morphological properties that are characteristic of the genus Planctomyces. In addition, morphologically uniform bacteria which reside inside the nuclei of host cells were observed. Using in situ hybridization with fluorescently labelled rRNA probes directed against known bacterial groups, the phylogenetic affiliation of the mesohyl bacteria was assessed. It could be shown that the vast majority of mesohyl bacteria belongs to the domain Bacteria with a low GC content. Among the Bacteria, the delta-Proteobacteria were most abundant, followed by the gamma-Proteobacteria and representatives of the Bacteroides cluster. Clusters of Gram-positive bacteria with a high GC content were also found consistently in low amounts. No hybridization signal was obtained with probes specific to the domain Archaea, to the alpha- and beta-Proteobacteria and to the Cytophaga/Flavobacterium cluster. This study describes for the first time the application of the “top-to-bottom approach” using 16S rRNA probes and in situ hybridization to assess the microbial diversity in Aplysina sponges. Received: 18 December 1998 / Accepted: 12 March 1999     

Studies on Rhizospheric Mycoflora of Tea (Camellia sinensis):In vitro Antagonism with Dominant Bacteria

The rhizospheres of established tea bushes have some specificcharacteristics which are associated with the long lived nature of teaplants,viz.,negative rhizospheric effect,lowering of soil pH,antagonistic activities among microbial communities and dominan…     

Antimicrobial activity of methanol extract of Origanum majorana L. (Sweet marjoram)

In-vitro microbicidal activity of the methanol extract of Origanum majorana L. was tested against seven fungi (Fusarium solani, Candida albicans, Aspergillus niger, A. parasiticus, Rhizopus oryzae, Rhizoctonia otyzae-sativae and Altemaria brassicicola) and six bacteria (Bacillus subtilis, B. megaterium, Escherichia coil, Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus). The methanol extract of O. majorana can be used as an effective herbal protectant against different pathogenic bacteria and fungi. High toxicity against the growth of Aspergillus niger was diagnosed.     

Interactions of bacteria and fungi on decomposing litter: differential extracellular enzyme activities

Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradative enzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria.     

Screening and bioassays for biologically-active substances from forty marine sponge species from San Diego,California, USA

Biologically-active substances were investigated from 35 demosponge species and 5 calcareous sponge species collected from intertidal or shallow subtidal habitats near San Diego, California, USA, from 1978 to 1980. Crude methanolic extracts of each species were tested for suppression of growth by bacteria (7 species) and a yeast. Antimicrobial activity was found in 26 Demospongiae and 2 Calcarea. Strong activity was found in 11 demosponges and, subsequently, 38 natural products with antimicrobial activity were isolated from 8 of these species (Aplysina fistularis, Dysidea amblia, Leiosella idia, Euryspongia sp., Toxadocia zumi, Axinella sp., Haliclona?cinerea and ?Pachychalina lunisimilis). Twenty-eight of these natural products (usually as pure compounds) were assayed for: (1) suppression of growth of marine fungi (3 spp.) and a red alga; (2) behavior modifications of invertebrate adults (4spp.); (3) toxicity to a goldfish; (4) inhibition of sexual reproduction of a brown alga; (5) inhibition of settlement and/or metamorphosis of late larvae or invertebrate juveniles (4spp.). Many of the natural products were also incorporated into pelleted fish food and tested for feeding-behavior modifications of fishes (5 spp.). Three of the compounds from Dysidea amblia were inactive in all tests. All other natural products were active in at least one assay, although none was active in all assays. The discussion relates the possession of biologically-active substances to the ecology of each sponge species; for example, sponges with antimicrobial substances are rarely overgrown.     

Cellular damage of plant pathogenic fungi by antifungal compounds produced by Bacillus spp. isolates

The use of microorganisms as biological control agents (BCAs) has become an effective alternative to chemical means of controlling plant pathogens. The antagonistic and inhibitory activity of 71 Bacillus spp. strains, which were isolated from different Mexican sites, were tested against several phytopathogen fungi, Fusarium oxysporum, Fusarium equiseti, Fusarium avenaceum, Bipolaris spp. and Alternaria spp. From the antagonism study, the strain ELI149 showed a marked inhibition of growth against all tested fungi; therefore crude metabolites from this strain were extracted using ethyl acetate and amberlite resin and probed against the same fungi as well as strains of Mucor sp., Penicillium spp. and Paecilomyces spp. The results indicated that amberlite was more suitable for extraction of secondary metabolites with antifungal activity. Finally, observation of cell damage in the tested pathogenic fungi showed marked morphological changes on reproductive structures in all tested fungi indicating that antibiosis was the mechanism of the antagonistic effect. These results suggest that metabolites from the Bacillus strains have a wide spectrum of antibiotic activities, which can be used as biocontrol agents for controlling fungal plant diseases of agricultural importance.     

Plasmid mediated antibiotic resistance in marine bacteria

This research work was conducted in Uppanar estuary to ascertain the role of plasmids in the antibiotic resistance of bacteria. Water and sediment samples were collected for a period of three months. When tested against 20 antibiotics 22 MAR strains were isolated from the samples, which were found resistant to 5-13 antibiotics. They belong to 7 genera and 10 species. Gram-negative bacteria namely Neisseria mucosa, N. sicca, Branhamella catarrhalis, Klebsiella ozaenae, Citrobacterintermedius, Pseudomonas fluorescens and Enterobacter aerogenes were isolated. Gram-positive bacteria were of Bacillus subtilis, B. megaterium and Micrococcus luteus. When plasmid curing was done using acredine orange, the resistance against penicillin-G, ampicillin, tetracycline, amoxycillin, kanamycin, and chloramphenicol were totally lost in all strains, which confirmed the role of plasmid in these strains against antibiotics. Ten strains belong to different species were selected for the plasmid isolation and electrophoresis was done. Presence of plasmids in all strains was confirmed and the molecular weight was in the range of 2850 to 3170 bp. The study revealed that MAR strains are common in Uppanar estuary and they are plasmid mediated. This environment is seemed to be deteriorating at an alarming rate.     

The enumeration and characterization of bacteria and fungi associated with marine wood-boring isopods,and the ability of these microorganisms to digest cellulose and wood

Bacteria and fungi associated with the marine wood-boring isopods Limnoria lignorum and Sphaeroma serratum, and with their wood burrows and seawater were investigated. Plate counts using nutrient agar and Czapex Dox agar media in natural and in artificial seawater were used. The diversity and number of bacteria associated with the two isopods were much higher than those associated with wood or seawater, whereas the opposite was true for fungi. The hydrolytic activity of the predominant genera on carboxymethylcellulose and on different types of wood was investigated. The magnitude of fungal cellulase activity exceeded that of bacteria. Activities of bacterial extracellulases exceeded those of intracellulases, while the opposite was observed for fungi. Cellulolytic activity of the predominant isolates biodegraded labkh, peach, white oak and mahogany in decreasing order of activity. Evidence provided by the cellulolytic activities, detected in woodcontaining cultures, suggests that the predominant micro-organisms isolated may play an important role in the woodboring process. Specimens used in the present study were collected from Port Fouad at Port Said Harbour, Egypt.     

Stress-induced rapid release of antibacterials by scleractinian corals

Mechanical stress on the coral Pocillopora damicornis caused the release of material that killed the coral pathogen Vibrio coralliilyticus. The bactericidal material was released into the surrounding seawater rapidly, reaching a maximum killing activity within 1 min of the stress. The coral antibacterial activity, referred to as CAA, was retained following filter sterilization and storage at –20°C. Exposure of V. coralliilyticus to CAA for 30 s, 1 min and 6 min resulted in the death of 82%, 89% and 99% of the bacteria, respectively. Release of CAA following mechanical stress was also observed with four other coral species tested. P. damicornis CAA was bactericidal to a wide variety of Gram-negative and Gram-positive bacteria. This is the first report that hard corals rapidly release fast-acting bactericidal material following mechanical stress. The release of CAA was demonstrated with both aquarium corals and corals taken directly from the sea. It is suggested that CAA is part of hard corals host defense system against infection, the natural stimulation for release of CAAs being the bite of a predator. Previous failures to detect antibacterial activity in hard corals can be attributed to a lack of understanding of the sensitive mechanism by which they are released.Communicated by M. Kühl, Helsingør     

Unravelling host and symbiont phylogenies of halichondrid sponges (Demospongiae, Porifera) using a mitochondrial marker

We present the first comparative phylogenetic analysis of a selected set of marine sponges and their bacterial associates. The Halichondrida form an important order in demosponge systematics and are of a particular interest due to the production of secondary metabolites. We sequenced a fragment of the cytochrome oxidase subunit 1 (CO1) gene of the sponges and their bacterial associates, compared the reconstructed phylogenies and found evidence for radiation in coevolution. The tree of six host-species associations showed four supported cospeciation events between the sponges and the bacteria. In addition, we present the first gene tree of sponges based on a mitochondrial marker. The tree shows major congruences with previous morphological studies and suggests the applicability of a mitochondrial marker in sponge molecular systematics.     

Effects of Arbuscular mycorrhizal fungi isolated from white clovers (Trifolium repens L) on soil bacteria and fungi

White clover potted experiments were performed to investigate the effects of seven indigenous arbuscular mycorrhizal fungi (AMF) communities isolated from different test plots subjected to long-term fertilisation on soil enzyme activities, number of soil bacteria and fungi. The results showed that the inoculation of arbuscular mycorrhizal fungi communities increased the mycorrhizal infection rate of the plants and promoted the growth of plants. The Mnp treatment was most effective. The shoot biomass, root biomass, potassium and nitrogen uptake of the white clover in Mnp treatment group were increased by 61.54%, 84.00%, 62.50% and 46.71% respectively, compared with those in non-inoculation treatment. The inoculation of AMF communities had little effect on the number of bacteria in the soil, but significantly increased the number of soil fungi. Mnk treatment group had the highest number of fungi in the soil, which was 9.91 times that of the non-inoculation treatment group. The catalase and dehydrogenase activities were both significantly improved in Mnp treatment by 28.12% and 205.38% respectively, compared with those of the control treatment (-M). The urease, invertase and cellulase activities reached the highest levels in the Mck treatment; they were increased by 142.79%, 41.17% and 77.62% respectively, compared with those of the control treatment. Pearson correlation analysis showed that the soil enzyme activity was not correlated with the mycorrhizal infection rate, but correlated with the spore number of the AMF community. The impact of AMF community on soil quality is important for us to understand the function of the ecosystems. Relevant study provides important guidance for maintaining the balance of the soil-plant system and the development of sustainable agriculture.     

New denitrifying bacteria isolated from Red Sea sediments

Sediments of various newly discovered deeps in the Red Sea were analyzed for the occurrence of denitrifying bacteria. The samples were collected in 1972 during the Valdivia cruises. Among the 27 different samples investigated, 17 revealed both coccoid and rod-shaped bacteria when enriched in complex nutrient broth (with 10% NaCl). Denitrifiers were recorded abundantly in the sediments, their population decreasing from some 10⁶/g in the surface material to only a few in the subsediment. A total of 16 pure cultures of denitrifying bacteria were isolated from the Suakin-and Thetis-deeps and studied morphologically, physiologically and biochemically. Genetics (molar percentage of guanine plus cytosine, % GC) and numerical taxonomy were included to reveal relationships and improve taxonomic classification. Fifteen isolates were described as Gram-negative, aerobic and facultative anaerobic (with NO ₃ ^- as H⁺-acceptor), polarly flagellated rods (Pseudomonas spp.); one was an inmotile, Gram-positive, facultative anaerobic coccus. None of the 15 Pseudomonas-isolates could be identified with one of the denitrifying species so far described and recognized. The strains should be regarded as hitherto undescribed denitrifying marine bacteria.Supported by the Bundesministerium für Forschung und Technologie, Bonn, Germany (FRG).