SYNTHESIS OF MESOPOROUS SILICA NANOPARTICLES AND DRUG LOADING FOR GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

Objective: To synthesize mesoporous silica nanoparticles using the sol-gel method and to determine the antibacterial activity of mesoporous silica nanoparticles and tetracycline loaded mesoporous silica nanoparticles.Methods: In the synthetic procedure, the surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) is initially dissolved in basic aqueous solution, and the mixture is vigorously stirred. Tetra Ethyl Ortho Silicate (TEOS) is added, and the solution is kept stirring for 6 h. After the reaction is complete, the as-synthesized product is filtered and washed with deionized water. The antibacterial was tested using disc diffusion method and minimum bactericidal concentration (MBC).Results: The synthesized mesoporous silica nanoparticles were characterized by using Scanning Electron Microscope (SEM) micrographs showed spherical particles with an average size of 350 nm. The powder X-Ray Diffraction (XRD) analysis of the material further confirmed the crystallinity of the mesopores as evidenced by the diffraction pattern of an intense peak at θ=24º. Fourier Transform Infra Red Spectroscopy (FTIR) indicated the involvement of carboxyl, amine and hydroxyl groups in the synthetic process. The result shows the inhibitory growth zone of 20 mm and 18 mm for tetracycline loaded mesoporous silica nanoparticles against Escherichia coli and Staphylococcus aureus respectively.Conclusion: To summarize, it has been experimentally demonstrated that mesoporous silica nanoparticle and tetracycline loaded mesoporous silica nanoparticles show very good antimicrobial behavior against the gram-positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria.Keywords: Mesoporous silica nanoparticles, Sol-gel method, Drug loading, Antibacterial activit

Bivalve resources of Moorad Estuary, north Kerala

A bivalve resource survey of Moorad estuary in Badagara District of north Kerala was carried out during February 2004 to assess the bivalve species, their distribution and potential stock. Sampling sites were fixed within five main zones of the Moorad estuary based on the clam fishery activities and local enquiries. The bivalve distribution in a unit area was taken by demarking the area of clam bed with a quadrant. Observations on the area of clam bed, water clarity, depth and temperature were recorded at each site. Surface and bottom water samples were collected and hydrographic parameters like salinity, temperature, pH and dissolved oxygen content, productivity, nitrate, phosphate and silicate were recorded. Sediment samples were collected to analyse the grain size and organic content of the clam beds. All samples were analysed within 24 h except sediment samples. Average density of bivalve per square metre area was analysed and the potential stock was estimated for each bivalve species in the estuary

Fishery and biology of Meretrix casta (Chemnitz) in the Moorad estuary, Kerala

Meretrix casta forms an important fishery in the Moorad estuary. The average annual landing for the period 2000-2004 was 426t, the average catch per effort was 573 kg and total effort was 3182. Clams ranging from 28 to 32 mm size contributed to the fishery. M casta is a continuous breeder with two peaks in March-April and August-September. The precentage edibility ranged between 8 and 16. The standing stock biomass in the Moorad estuary was estimated at 2073 t with an average density of 1096 numbers per sq. m. The present status and management options for this important fishery are discussed

Food and feeding habits of the narrow barred Spanish mackerel Scomberomorus commerson (Lacepede, 1800) off Karnataka, south-west coast of India

Scomberomorus commerson were collected on weekly basis during January 2012 to December 2014 at Mangalore Fishing Harbour. Stomach of 214 narrow barred Spanish mackerel measuring from 48 to 105 cm fork length (FL) for males and 45.5 to 115 cm FL for females were analysed to study their feeding habits. Fish with empty stomach were prevalent in almost all the months. Prey mainly comprised of fishes and crustaceans, with the fish component forming 99.9%. The index of relative importance (IRI) showed that the dominant prey were semi-digested fish remains (44.6%) of Sardinella longiceps (30.1%), Decapterus sp. (18.7%), whitebaits (2.5%), Rastrelliger kanagurta (1.5%) and Epinephelus spp. (1.1%), while Saurida sp. (0.7%), Megalaspis cordyla (0.5%), Scombroides sp. (0.2%) and shrimps (0.1%) were found occasionally in the gut. Index of stomach fullness (SFI) was 0.11 in August and 0.65 in January. Generally, SFI was higher during September to January and lower during February to August. The empty stomach ratio (ESR) ranged from 33.3% (August) to 92.3% (April)

Shift in diet composition of Indian mackerel Rastrelliger kanagurta - an analysis in relation to climate change

The feeding regime of organisms depend on the plankton community structure which is being studied worldwide to assess the changes in marine ecosystem structure due to climate change or anthropogenic activities. An attempt is made here to study the seasonal and long term variation in feed composition of Indian mackerel over a period of 40 years and its relationship with sea surface temperature to elucidate structural changes in food composition if any over period of time and its relationship to the primary and secondary productivity in eastern Arabian Sea marine ecosystem. The diet study during 2011-2014 reported the domination of phytoplankton consisting of Coscinodiscus sp. consistently and the presence of macroplankton and fish larvae whereas the diet during 1960-1961 showed the dominance of zooplankton and copepods. It could be assumed that increase in sea surface temperature which resulted in dominance of phytoplankton community as reported elsewhere in the world is also observed in eastern Arabian Sea which is reflected in the diet regime of Indian mackerel. The results also indicate its facultative feeding behaviour by compensating the low value phytoplankton with high value macroplankton and hence can be considered as a resilient species with regard to climate change

Fabrication of green nanoinsecticides from agri-waste of corn silk and its larvicidal and antibiofilm properties

he corn silk (CS) is composed of the thread- like stigmas of female inflorescences of Zea mays L. and represents an important waste material from maize crop production that can be recycled in further applications. In this research, the CS was used for the bio-fabrication of Ag nanoparticles (AgNPs) that were evaluated against (I–V) larval instars and pupae of the mosquito vector Aedes aegypti. CS-AgNPs were characterized by UV-Vis spectroscopy, TEM, EDAX, XRD, FTIR, DLS, and zeta potential analysis. Z. mays extract analyzed by gas chro- matography mass spectrometry reveals 14 compounds. The larvicidal effectiveness of CS-fabricated AgNPs was 2.35 μg·mL−1 (I Instar) to 6.24 μg·mL−1 (pupae). The field application in water storage reservoirs of both CS extracts and CS-AgNPs (10 × LC50) led to a 68–69% reduction in larval density after 72 h post-treatment. Ecotoxicological impact of CS-fabricated AgNPs was evaluated on the pre- datory efficacy of Poecilia reticulata on all the larval instars and pupae of Ae. aegypti. Finally, CS-AgNPs were tested to elucidate its anti-biofilm attributes. The CS-AgNPs at 125 μg·mL−1 showed a biofilm inhibition of 90% on S. aureus and 79% on S. epidermidis. These results support the use of CS-AgNPs for futuristic green alternative to mosquito vector management

Study on the reproductive behavior among women of rural areas of Pondicherry

Background: The fertility rate in India is declining and it is necessary to know the factors responsible for such decline in different states. It was decided to study reproductive behavior of women contributing to decline in fertility in Pondicherry. The aim and objective of this study is known the reproductive behavior of women in the rural areas on Pondicherry.Methods: Sample of 300 married women aged between 30 and 60 years were selected randomly from village belonging to Katerikuppam PHC and the data collected using the pre tested semi open ended questionnaires by interviewing the subjects at their doorsteps during September to November 2014.Results: The mean age of the subjects was 41.5 ± 9.5 years. There were 793 total pregnancies and live births were 701 and abortions accounted for ten percent and still births were 9 in number. The mean number of pregnancies and live births were 2.6 ± 1.1 and 2.3 ± 1.0 per women respectively. The mean age at menarche, marriage and first pregnancy were 14.3 ± 1.4, 19.6 ± 3.1 and 21.1 ± 3.1 years respectively. The mean number of pregnancies were declined from currently older age to the lower age of the subjects and found to be statistically significant.Conclusions: The mean age at marriage and first pregnancy is increasing and the differences in the mean number of pregnancies and live births are showing declining trend.

Instance of unusual feeding habit of the Indian Mackerel, Rastrelliger kanagurta from the Mangalore Fishing Harbour

The Indian mackerel, Rastrelliger kanagurta contributes significantly to the pelagic fishery catch of Dakshina Kannada coast. The fishing season extends from Aug. to May with peak landings during September-November and April-May. Fishing is done by purseseiners, trawlers, gillnetters, ring seiners and indigeneous non mechanized crafts

Aberrations in the feeding behaviour of the Indian Mackerel, Rastrelliger kanagurta

The food and feeding habits of the mackerel have been studied extensively, which suggest that mackerel generally adopts either filter feeding or preying on the individual animals. Plankton consisting of copepods, diatoms and dino-flagellates and small crustaceans such as the Acetes sp. are reported in their feed. However, a deviation from the normal feeding habit was observed in the gut analysis of mackerel collected on 8th October 2013 from trawlers at Mangalore Fisheries Harbour. Among the 50 stomachs analysed 4% contained oil sardines juveniles and 2% had digested squid remains as a food item. The specimens which ranged from 192 mm to 285 mm in total length and weighed 67 g to 224 g were mature with their gonad in spent or spent recovery stages. The semi-digested oil sardine present in the gut of mackerel ranged in size from 36 to 81 mm

Climate influence on oil sardine and Indian mackerel in Southeastern Arabian sea

The anomalies of sea surface temperature, coastal upwelling index, rainfall, multivariate ENSO index and chlorophyll a were analysed and correlated with catch rate anomalies of oil sardine and Indian mackerel exploited by purse seine along the coastal waters off Karnataka, India in South-Eastern Arabian Sea during period 1990–2014. The purse seines in Karnataka contributed on an average 75% and 65% catch of oil sardine and Indian mackerel respectively. The catch rate anomalies of oil sardine, showed a significant positive correlation with sea surface temperature and negative statistical correlation with multivariate ENSO index. Such significant relationship was not observed in the case of Indian mackerel. The relationship of those parameters to variations in catch distribution of oil sardine and Indian mackerel was explored with a generalized additive model. The GAM results indicated that for sardine, sea surface temperature ( R–sq = 0.339) with 40.8% deviance and for mackerel, chlorophyll a (R–sq =0.419) with 58.9% deviance were better than other climatological factors and can be considered as a climatological predictor of catches in the region. The study also indicated a combination of sea surface temperature and multivariate ENSO index anomalies had better deviance of 56% for oil sardin