Multifarious plant growth-promoting traits of mangrove yeasts: growth enhancement in mangrove seedlings (Rhizophora mucronata) for conservation.

Plant Growth-Promoting Yeasts (PGPY) have garnered significant attention in recent years; however, research on PGPY from mangroves remains a largely unexplored frontier. This study, therefore, focused on exploring the multifaceted plant growth-promoting (PGP) capabilities of yeasts isolated from mangroves of Puthuvype and Kumbalam. The present work found that manglicolous yeasts exhibited diverse hydrolytic properties, with the predominance of lipolytic activity, in addition to other traits such as phosphate solubilization, and production of indole acetic acid, siderophore, ammonia, catalase, nitrate, and hydrogen cyanide. After screening for 15 PGP traits, three strains P 9, PV 23, and KV 35 were selected as the most potent ones. These strains also exhibited antagonistic activity against fungal phytopathogens and demonstrated resilience to abiotic stresses, making them not only promising biocontrol agents but also suited for field application. The potent strains P 9, PV 23, and KV 35 were molecularly identified as Candida tropicalis, Debaryomyces hansenii, and Aureobasidium melanogenum, respectively. The potential of these strains in enhancing the growth performance of mangrove seedlings of Rhizophora mucronata, was demonstrated using the pot-experiment. The results suggested that the consortium of three potent strains (P 9, PV 23, and KV 35) was more effective in increasing the number of shoot branches (89.2%), plant weight (87.5%), root length (83.3%), shoot height (57.9%) and total leaf area (35.1%) than the control seedlings. The findings of this study underscore the significant potential of manglicolous yeasts in contributing to mangrove conservation and restoration efforts, offering a comprehensive understanding of their diverse plant growth-promoting mechanisms and highlighting their valuable role in sustainable ecosystem management.

Plant growth-promoting yeasts (PGPY), the latest entrant for use in sustainable agriculture: a review.

Synthetic fertilizers and pesticides are being extensively used in agriculture in order to increase food production to feed the rapidly growing world population. This has negatively affected the soil microbes thereby reducing the agricultural produce. As a safer alternative, microbial fertilizers are now being used as plant growth promoters to improve agricultural yields. A large number of studies are focused on the role of bacteria and multicellular fungi, but plant growth-promoting traits of yeasts, the unicellular fungi are little known. Hence, the present article reviewed the diverse groups of yeasts with the potential to act as plant growth promoters. Plant growth-promoting yeasts (PGPY) have been mainly isolated from the rhizosphere and phyllosphere of major crop plants such as wheat, maize, and rice. Twenty-three genera of yeasts have been reported to have the potential for plant growth promotion (PGP), most of which belong to the phylum Ascomycetes. Dominant PGPY genera include Candida spp., Rhodotorula spp., Cryptococcus spp., and Saccharomyces sp. PGPY are known to exhibit phyto-beneficial attributes viz phytohormone production, phosphate solubilization, siderophore production, improved soil fertility, aid plants to tolerate abiotic stress and also compete effectively against plant pathogens. Over and above these traits, PGPY is Generally Recognized as Safe, making it an ideal candidate to be effectively employed as part of sustainable agricultural practices to ensure food security. The review warrants a need for an in-depth study on the different sources of PGPY other than rhizosphere/phyllosphere and the genes controlling PGP traits.

Genetic diversity in three populations of Avicennia marina along the eastcoast of India by RAPD markers.

Genetic diversity was analysed in three populations of the mangrove species, Avicennia marina by using random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Ten random decamer primers were used to score the diversity from three locations of eastcoast of India: Parangipettai (Tamil Nadu), Kakkinada (Andhra Pradesh) and Sundarbans (West Bengal). These primers produced 388 scorable DNA fragments, of which 252 (64.98%) were polymorphic, 182 (46.90%) were monomorphic, and 14 (3.61%) were unique. RAPD banding patterns displayed variations between and within the populations, while, there was no morphological variation.

Spatial and temporal distribution of macrobenthos in different mangrove ecosystems of Tamil Nadu Coast, India.

This paper deals with the spatial distribution and diversity of macrobenthos and their relationships between physico-chemical parameters of the water and sediment in different mangrove habitats of Tamil Nadu, India during different seasons (2008). Among the different ecosystems of mangrove benthic faunal assemblages, macrofauna species number, density, richness, and Shannon-Wiener index were the highest and the Simpson dominance index was medial at riverine mangrove community. However, the Pielou Evenness index of riverine mangrove community was slightly lower than other communities. The similarities among the macrobenthic communities at different sampling sites were determined using Bray-Curtis similarity coefficient and ordinations of non-metric multidimensional scaling (MDS). Thirty-one species were recorded in developing (16 polychaetes, six bivalves, seven gastropods, and two crustaceans), 35 species were recorded in riverine (20 polychaetes, six bivalves, five gastropods, and four crustaceans) and 31 species were recorded in island mangrove ecosystem (19 polychaetes, four bivalves, five gastropods, and three crustaceans). Among the three ecosystems, a total of 46 benthic macrofauna consisting of 27 species of polychaetes, eight species of gastropods, seven species of bivalves, and four species of crustaceans were recorded. However, there were obvious differences among the community structures in the three mangrove habitats. This result implied that the different mangrove ecosystem had different effects on the macrofauna communities and shed light on the macrofauna adaptation capability to specific habitats.

In-vitro antioxidant potential and acetylcholinesterase inhibitory effect of Ficus benghalensis aerial root extract.

Aim and objective: The aim of the current study was to evaluate the antioxidant effect, acetylcholinesterase (AChE) inhibitory effect and phytochemical screening of different extracts of aerial root extract of Ficus benghalensis using in-vitro methods. Methods: The aerial root extract was prepared by successive extraction method using different organic solvents having increasing order of polarity. FB aerial root extract was screened for preliminary phytochemical analysis. FB aerial root extracts were evaluated for in-vitro acetylcholinesterase inhibitory effect by the Ellman's method and anti-oxidant potential by DPPH assay and hydroxyl radical neutralizing assay. Results: Preliminary phytochemical screening of FB extracts indicate the existence of the phytochemicals such as phenols, alkaloids, flavonoids, glycosides, anthraquinones, tannins and steroids. The results of the DPPH assay, hydroxyl radical scavenging assay and AChE inhibitory assay show that chloroform and ethyl acetate extracts are having significant antioxidant activity and acetylcholinesterase inhibitory effect as compared to the other extracts, respectively. Conclusion: The results of the current study suggest that the aerial root extract of FB might be a potential drug source for treatment of neurodegenerative disorders like Alzheimer disease.

Nanotherapeutics to overcome conventional cancer chemotherapy limitations.

Cancer is one of the major causes of death worldwide and chemotherapy is a major therapeutic approach for the treatment which may be used alone or combined with other forms of therapy. However, conventional chemotherapy suffers lack of aqueous solubility, lack of selectivity and multidrug resistance. Nanotherapeutics is rapidly progressing aimed to solve several limitations of conventional drug delivery systems. Nonspecific target of cancer chemotherapy leads to damage rapidly proliferating normal cells and can be significantly reduced through folate and transferrin mediated nanotherapeutics which are aimed to target cancerous cells. Multidrug resistance is challenge in cancer chemotherapy which can be significantly reversed by solid lipid nanoparticles, polymeric nanoparticles, mesoporous silica nanoparticles, nanoparticulated chemosensitizer, nanoparticluated poloxamer and magnetic nanoparticles. Hydrophobic nature of chemotherapeutics leads to poor aqueous solubility and low bioavailability which can be overcome by nanocrystals, albumin based nanoparticles, liposomal formulation, polymeric micelles, cyclodextrin and chitosan based nanoparticles. This review focuses the role of nanotherapeutics to overcome lack of selectivity, multidrug resistance and lack of aqueous solubility of conventional cancer chemotherapy.

Effect of neem extract against the bacteria isolated from marine fish.

Marine ornamental fishes are exceedingly valuable due to their high demand in domestic and international markets. There is a growing global interest to rear the fishes in captivity. But problem due to bacteria and fungi are the major hitch in captive condition. Since, the use of antibiotics is banned, an attempt was made to ascertain in vitro assay of the neem leaves extract against the bacterial pathogens isolated from infected fishes. Bacterial strains isolated from infected regions of the clown fishes Amphiprion sebae and A. ocellaris were identified as Aeromonas hydrophila, Enterobacter sp., E. coli, Pseudomonas aeruginosa, Proteus sp., Streptococcus sp., Vibrio cholerae, V. alginolyticus, V. parahaemolyticus and Yersinia enterocolitica. Ethanol and methanol extracts were highly inhibitory to the bacterial isolates when compared to other solvents. Ethanol extracts exhibited low minimum inhibitory concentration (75-250 microg ml(-1)) as compared to other extracts. The present finding revealed that the neem leaf extract significantly reduces the bacterial pathogens and their infection in marine ornamental fishes.

Temperature effect on chemical-induced carcinogenesis in hamster cheek pouch.

7,12-Dimethylbenz[a]anthracene (DMBA), a potent chemical carcinogen, was used to induce oral cancer on hamster buccal pouch, under two temperature regimes (22±2 and 28±2°C) for 25 weeks of observation. The animal group under high temperature showed rapid tumour incidence and weight loss. It also exhibited biochemical changes such as reduced lipid peroxidation in the oral tumour tissue, accompanied by significant increase in the levels of reduced glutathione, glutathione peroxidase and glutathione-s-transferase. Therefore, we propose that elevated temperature is a cofactor, accelerating the process of DMBA-induced carcinogenesis in hamster cheek pouch.

Growth of Avicennia marina and Ceriops decandra seedlings inoculated with halophilic azotobacters.

Inoculation of azotobacter has significant positive effects on the growth characteristics and pigments in mangrove seedlings of Avicennia marina and Ceriops decandra. The bacterial inoculation significantly increased the root dry biomass at the maximum of 75.8% at 30 gl(-1) salinity in Ceriops decandra. But in Avicennia marina, the shoot dry biomass was increased significantly at the maximum of 56.12% at 30 gl(-1) salinity in general, the Azotobacter beijerinkii improved the growth characteristics better in both species of mangroves preferably at higher salinity levels in A. marina and at a range of salinity in C. decandra. The results recommend this forraising vigorous seedlings under nursery conditions.

Antimicrobial activity of tissue and associated bacteria from benthic sea anemone Stichodactyla haddoni against microbial pathogens.

Associated bacteria from Stichodactyla haddoni are found maximum in tentacle tissues than the body tissue. There are eight associated bacterial species viz., Alcaligenes sp, Corynebacterium sp, Aeromonas sp, Sporosarcina sp, Renibacterium sp, Camobacterium sp1, Camobacterium sp2 and Salinococcus sp were recorded. The culture extracts from the associated bacterial species showed sensitivity against human bacterial and fungalpathogens. However, the hexane tissue extract of sea anemone showed maximum sensitivity (24 mm dia.) against the fish bacterial pathogen Aeromonas hydrophila than the other chosen pathogens. Comparatively the tissue extracts showed promising antimicrobial sensitivity than the cell free extracts of associated bacteria, and hence, the tissue samples from the sea anemone Stichodactyla haddoni is recommended for further exploration of novel antimicrobial drugs than the associated bacteria.

Bioprospects of Microbial Enzymes from Mangrove-Associated Fungi and Bacteria.

Mangroves ecosystem provides the unique habitat for the colonization of fungi and bacteria. Interestingly, the enzymes derived from mangroves associated microorganisms have enormous economic value in industries of agriculture, pulp, paper, medicine, sewage treatments, etc. Microbial enzyme activity is required for the metabolism of plants and animals. In addition, the enzymes are also involved in aquatic animal food cycle and degradation of mangroves detritus. However, the understanding of current status of mangroves associated microorganism-derived enzymes and its application is required to improve the future omics studies. Therefore, this chapter is summarizing the current reports and application on enzymes derived from mangroves associated bacteria and fungi.

Making artificial honey using yeast cells from salivary glands of honey bees.

The salivary glands of a honey bee, Apis cerana and the yeast cells isolated from these glands were studied for their effects on sucrose solution. This solution exhibited lowered pH and increased levels of fructose and total amino acids as the time of incubation proceeded. The solution thus made was similar to the natural honey.

Antiviral properties of a mangrove plant, Rhizophora apiculata Blume, against human immunodeficiency virus.

A polysaccharide extracted from the leaf of Rhizophora apiculata (RAP) was assessed in cell culture systems, for its activity against human and simian immunodeficiency viruses. RAP inhibited HIV-1 or HIV-2 or SIV strains in various cell cultures and assay systems. It blocked the expression of HIV-1 antigen in MT-4 cells and abolished the production of HIV-1 p24 antigen in peripheral blood mononuclear cells (PBMC); the 50% effective concentration (EC50) of RAP in HIV-1 infected MT-4 cells and in PBMC was 10.7 and 25.9 microg/ml, respectively. RAP (100 microg/ml) completely blocked the binding of HIV-1 virions to MT-4 cells. RAP also reduced the production of viral mRNA when added before virus adsorption. RAP inhibited syncytium formation in cocultures of MOLT-4 cells and MOLT-4/HIV-1(IIIB) cells. RAP did not prolong activated partial thromboplastin time (APTT) up to 500 microg/ml. These properties may be advantageous should RAP be considered for further development.

Purification of anti-HIV protein from purple fluid of the sea hare Bursatella leachii de Blainville.

The purple fluid of Bursatella leachii, already found to have anti-HIV activity, was selected and tested for purification and characterization of an anti-HIV protein. Only one fraction showed anti-HIV activity at the minimum inhibition concentration of 50 mg/ml. This purified anti-HIV protein has been named as "Bursatellanin-P" after the animal species Bursatella leachii. About 3 mg of the pure protein was obtained from 1000 ml of purple fluid. The anti-HIV activity increased by about 135-fold in the purified sample, as compared with the crude purple fluid. The purified protein, which showed anti-HIV activity, was a single unit with a molecular weight of 60 kDa. The protein was stable between pH 5.8 and 8.0. It lost its activity with heating at 60 degrees C for 10 minutes and also with extreme pH values of 2.0 or 10. The protein was resistant to digestion of proteinase K and mercaptoethanol.

In vitro anti-vaccinia virus activity of some marine plants.

Seventy three marine plant extracts were tested in vitro in chick embryo fibroblast cell culture and their anti-vaccinia virus activity was evaluated in terms of reduction in number of plaques by the extracts. Only seven extracts were found to show the activity. Sargassum wightii, a seaweed had the highest activity, reducing 65 per cent of plaques formed by vaccinia virus.

In vitro anti human immunodeficiency virus activity of mangrove plants.

Mangrove plant extracts were screened in vitro against human immunodeficiency virus (HIV) on MT-4 cells. HIV infected MT-4 cells were cultured for five days in the presence of the extract, at various concentrations. Anti-HIV activity was evaluated by tetrazolium-based colorimetric assay. Seven extracts were found effective. Five of the active extracts completely inhibited the virus adsorption to the cells. Most of the active plants are from the family Rhizophoraceae.

A survey of some Indian medicinal plants for anti-human immunodeficiency virus (HIV) activity.

BACKGROUND & OBJECTIVES: India has an extensive area of forest enriched with plant diversity. Several of these plants have been used as folklore medicines. However, the medicinal plants have rarely been investigated for anti-human immunodeficiency virus activity. Hence, some Indian medicinal plants were screened in vitro against human immunodeficiency virus (HIV). METHODS: The inhibitory effect of plant extracts on HIV replication was monitored in terms of inhibition of virus induced cytopathogenicity in MT-4 cells. The MT-4 cells were infected with HIV. The HIV infected or mock infected MT-4 cells were incubated at 37 degrees C in a CO2 incubator in the presence of the plant extracts. After five days, cell viability was measured by tetrazolium based colorimetric assay. RESULTS & INTERPRETATION: Of the 69 plant species screened, 16 were effective against HIV-1 and 4 were against both HIV-1 and HIV-2. The most effective extracts against HIV-1 and HIV-2 are respectively Cinnamomum cassia (bark) and Cardiospermum helicacabum (shoot + fruit). The findings provide a rationale for further studies on isolation of active principles and pharmacological evaluation.

Radical modulation activity of lignins from a mangrove plant, Ceriops decandra (Griff.) Ding Hou.

The radical modulation activity of hot water and alkaline extracts from leaf of Ceriops decandra, a mangrove plant, was investigated using ESR spectroscopy. IR and NMR analyses demonstrate that the leaf extracts have a lignin-like polyphenolic structure. All these extracts produced radical(s) under alkaline conditions. The radical intensity of sodium ascorbate was slightly reduced at lower concentrations of the extracts, but it was synergistically enhanced at higher concentrations. All the extracts effectively scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction. Pretreatment of mice with the extracts significantly protected them from the lethal infection by E. coli. Similar activity was found in lignins from pine seed shell of Pinus parviflora Sieb. et Zucc. These data further support the medicinal efficacy of plant extracts.

Effect of probiotics on bacterial population and health status of shrimp in culture pond ecosystem.

The artificially manufactured probiotics having beneficial bacteria, Bacillus spp. was applied regularly in a modified extensive shrimp (Penaeus monodon) culture pond, located on the bank of Vellar estuary, Parangipettai. The populations of total heterotrophic bacteria (THB), beneficial bacteria (Bacillus spp.) and pathogenic bacteria (vibrios) were monitored in water and sediment of the pond. The results were compared with a control pond, situated in the same location having same water spread area, stocking density, species managed with same technologies and optimum environmental parameters in which no probiotic was applied. The populations of THB and Bacillus spp. in the experimental pond increased and the vibrios decreased after each application of probiotics. But the result of the control pond showed an increasing trend of the populations of THB, Bacillus spp. and vibrios towards days of culture. The control pond had lower levels of THB and Bacillus spp. and higher levels of vibrios than the probiotic applied (experimental) pond. Also the probiotics maintained optimum transparency and low organic load in the experimental pond as compared to control. In general, water and sediment had almost equal number of Bacillus spp. and vibrios, but sediment had higher THB load than water. The applications of probiotics lesser pathogenic vibrios and enhance beneficial bacilli in the culture leading to improved water quality, promoted growth and survival rates and increased the health status of the shrimp without stress and disease outbreaks. Thus the application of probiotics could lead to disease-free and profitable shrimp culture operations which will be helpful for shrimp farmers as most of them are now-a-days severely affected by microbial diseases.

How to alleviate degradation of mangroves?

This work has experimentally proved that hyper salinity, a major cause for degradation of coastal mangrove habitats, can be alleviated by flushing of hyper saline soil with tidal water and/or with rainwater. Over a period of three years after digging the creeks to flush hyper saline soil with tidal water, an appreciable reduction in soil salinity and a moderate increase in colonization of mangroves are observed. Soil analysis showed a significant reduction in salinity after 2 months of storage of rainwater with a significant and concomitant increase of heterotrophic bacterial counts and nutrients. This study raises the possibility of converting degrading mangrove habitats to luxuriant ones through man-made efforts.