Increased chemical weathering during the deglacial to mid-Holocene summer monsoon intensification.

Chemical weathering and the ensuing atmospheric carbon dioxide consumption has long been considered to work on geological time periods until recently when some modelling and natural records have shown that the weathering-related CO2 consumption can change at century to glacial-interglacial time scale. Last glacial to interglacial transition period is a best test case to understand the interplay between Pco2-temperature-chemical weathering when a pulse of rapid chemical weathering was initiated. Here we show, from a high resolution 54 ka record from the Andaman Sea in the northern Indian Ocean, that the chemical weathering responds to deglacial to mid-Holocene summer monsoon intensification in the Myanmar watersheds. The multi-proxy data (Al/K, CIA, Rb/Sr, 87Sr/86Sr for degree of weathering and 143Nd/144Nd for provenance) reveal an increase in silicate weathering with initiation of interglacial warm climate at ~17.7 ka followed by a major change at 15.5 ka. Inferred changes in chemical weathering have varied in tandem with the regional monsoonal proxies (δ18Osw-salinity changes of Northern Indian Ocean, effective Asian moisture content and δ18O records of Chinese caves) and are synchronous with changes in summer insolation at 30°N and δ18O of GISP2 implying that chemical weathering was not a later amplifier but worked in tandem with global climate change.

Specific and nonspecific immunostimulation study of Euphorbia hirta on Pseudomonas fluorescens-infected Cyprinus carpio.

CONTEXT: Infectious diseases are one of the major factors affecting the production of fish worldwide. The pathogens (especially bacteria) affect the immune system of fish and the administration of immunostimulants can increase resistance to infectious diseases by enhancing both specific and nonspecific defense mechanisms. OBJECTIVE: In the present study, we have conducted an experiment on the pathogen-infected Cyprinus carpio Linn. (Cyprinidae), using Euphorbia hirta Linn. (Euphorbiaceae) plant leaves as immunostimulants. MATERIALS AND METHODS: The aqueous extract of the leaves was prepared and the immunostimulant action was recorded by giving different concentrations of plant extract supplemented diet. RESULTS AND DISCUSSION: The results obtained from the studies show that the higher concentration of the extract (50 g/kg diet) provided significant immune response (specific and nonspecific) on the fish. The 50 g/kg leaf extract of E. hirta enhanced the phagocytic ratio on 10th and 15th day after the infection. The results of the specific and nonspecific immunostimulation studies are statistically significant. CONCLUSION: This work will guide the researchers for the discovery of significant aquaculture nutrients to improve the immunostimulant action on fish.

Optimization of artificial fertilization in the stinging catfish Heteropneustes fossilis (Bloch).

Determination of optimum sperm requirement in artificial breeding helps to improve the fertilization efficiency, sperm economy and minimize the sacrificing of males for milt. Quantification of sperm cells was done by spectrophotometer at 420 nm followed by haemocytometer counting. Best correlation (r2 = 0.97) was recorded. The minimum number of sperm required for optimal fertilization success in Heteropneustes fossilis was determined. An average fertilization success of 78-93% was recorded at 8 × 103 to 8 × 107 sperm per egg. The optimum contact duration of gametes was 5 minutes. The highest fertilization rate of 98.18% was recorded at 8 × 107 spermatozoa.egg-1.

Immunomodulatory activity of Aegle marmelos in freshwater fish (Catla catla) by non-specific protection.

CONTEXT: The production of fish is limited by infectious diseases; when a fish grows in an immunosuppressed condition, it becomes highly susceptible to disease. OBJECTIVE: The present research work investigates immunomodulatory action of Aegle marmelos (Linn.) Corr. Serr. (Rutaceae) in Catla catla Hamilton (Cyprinidae) for enhancing immune protection of the fish against bacterial infections. MATERIAL AND METHODS: Doses of 0, 5, 10, 15, 20, 25 and 30 g aqueous plant leaf extract/kg feed were administered orally to the freshwater fish, Catla catla for a period of 30 days to investigate its efficiency to enhance the non-specific immune responses against the fish pathogen Pseudomonas aeruginosa (Schröter) Migula (Pseudomonadaceae). RESULTS AND DISCUSSION: The fish were challenged with pathogens through water medium for 30 days and the immunomodulatory effect of the Aegle marmelos was evaluated on the blood samples every 5 days until 15 days after infection. The results obtained from the study shows that the 25 g leaf extract/kg of feed was found to be competent to enhance optimum immune response. The effectiveness of the immunostimulant action was found to be best for the first 5 days after challenging with pathogen and subsequently, the immune response was found to decline in all the concentrations of plant extract. CONCLUSION: The results of the study will be helpful for further investigation in the field to improve the immunocompetence of fish against bacterial pathogens.

Vaccine adjuvants - Current status and prospects on controlled release adjuvancity.

The strategy of World Health Organization is to develop efficient and inexpensive vaccine against various infectious diseases amongst children's population. Vaccination is considered as the most cost effective health intervention known to public. Since 90 years various substances have been added in vaccine formulation but still alum is considered as the safest adjuvant for human use licensed by United States Food and Drug Administration. MF 59 and ASO4 are the adjuvants were developed recently and approved for human use. Due to poor adjuvancity, conventional vaccines require multiple recall injection at approximately time intervals to attain optimal immune response. For past approximately two decades the vaccine research has been focused towards the alternation of alum type of adjuvant in order to increase the immunogenicity. The development of new vaccines, is more efficacious or easier to deliver, or both have become an area of research that can certainly benefit from controlled release technology. Especially, the conversion of multiple administration vaccine into single administration vaccine may represent an improved advancement towards the betterment of human health care and welfare. Biodegradable polymer microparticles have been evaluated for delivering antigens in native form, sustained release keeping in mind the safety aspects. In this article we review the overall concept of adjuvants in vaccine technology with special focus towards the prospects of controlled release antigens.

Immunomodulatory effect of Aegle marmelos leaf extract on freshwater fish Cyprinus carpio infected by bacterial pathogen Aeromonas hydrophila.

CONTEXT: Aquatic organisms (especially fish) require potent defense mechanisms to protect themselves against pathogen invasion and disease formation. The use of immunostimulants in fish culture can prevent the diseases through augmentation of both specific and non-specific immunity. OBJECTIVE: A study was conducted to investigate the efficacy of different dietary doses of Aegle marmelos (Linn.) Corr. Serr. (Rutaceae) leaf extract for the immune response and the disease resistance of the freshwater fish, Cyprinus carpio Linn. (Cyprinidae) infected by Aeromonas hydrophila Chester (Aeromonadaceae). MATERIALS AND METHODOLOGY: Hematological, specific immune response, non-specific immune response and enzyme assay studies were performed on fish and were scrutinized after 50 days of feeding trial. RESULTS: Fish were challenged with Aeromonas hydrophila at a dose of 1.5 × 10(4) cells/mL through intraperitoneal injection, and the hematological changes, the immune response, the enzyme activity and the disease resistance of Cyprinus carpio against the pathogen were also studied for 20 days at 5-day intervals. DISCUSSION: The results obtained from the study demonstrated that the fish fed with leaf extract of Aegle marmelos incorporated into feed significantly enhanced the red blood cell count, white blood cell count, hemoglobin, phagocytic activity, nitroblue tetrazolium chloride assay, lysozyme, pathogen clearance and enzyme activity compared with the control group. The survivability was higher in the fish which consumed leaf extract-incorporated feed, and the fish group fed with 5 g diet showed highest percentage survival of the fish. CONCLUSION: These results indicate that Aegle marmelos stimulates the immunity and makes the freshwater fish Cyprinus carpio more resistant to Aeromonas hydrophila.

Immune Augmentation of Single Contact Hepatitis B Vaccine by Using PLGA Microspheres as an Adjuvant.

The present study was aimed to replace the alum type adjuvant for hepatitis B vaccine. The hepatitis B vaccine was encapsulated in poly (DL-lactide-co-glycolide) microspheres by solvent evaporation technique. The formulated microspheres were characterized in terms of morphology, particle size analysis, in vitro release study and in vivo immune response in male Wistar rats. The FT IR spectrum illustrates the characteristics bands of poly (DL-lactide-co-glycolide) microspheres and hepatitis B vaccine at 1750 cm(-1) and 1650 cm(-1), respectively. The hepatitis B vaccine loaded poly (DL-lactide-co-glycolide) microspheres were able to release antigens till day 42. Significant enhancement of specific antibodies to HBsAg was produced till day 90 after a single administration of HBsAg encapsulated poly (DL-lactide-co-glycolide) microspheres. However, the conventional alum adsorbed hepatitis B vaccine was not found to produce any significant specific antibody levels till day 90 after a single dose. The results showed that poly (DL-lactide-co-glycolide) microspheres show potential as an adjuvant for hepatitis B vaccine.

Freezing injury in potato leaves.

Time-temperature profiles of freezing leaves from frost-resistant (Solanum acaule Bitt.) and frost-susceptible (Solanum tuberosum L. subsp. tuberosum Hawkes) types of potatoes did not reveal any major differences. The pattern of change in resistance of leaves to low voltage, low frequency current during freezing was different in the frost-resistant and susceptible leaves. In tissue sections from both types of leaves, cells freeze extracellularly at cooling velocities lower than 5 C per minute. Cells from leaves of resistant plants showed a higher osmotic pressure but not a higher water permeability than those from susceptible plants. The extent of injury caused by even very slow freezing was greater than that caused by equivalent isopiestic desiccation, particularly in susceptible leaves. The higher osmotic pressure in cells of leaves from resistant plants can account for the greater desiccation resistance but not for the frost resistance observed.