Degradation of barnacle nauplii: implications to chitin regulation in the marine environment

Biologia ◽  
2013 ◽  
Vol 68 (4) ◽  
Author(s):  
Lidita Khandeparker ◽  
Chetan Gaonkar ◽  
Dattesh Desai
Keyword(s):  
Marine Environment ◽  
Pathogenic Bacteria ◽  
Treatment Time ◽  
Marine Ecosystem ◽  
Degradation Process ◽  
Bacterial Attachment ◽  
Scanning Electron Micrographs ◽  
Nutrient Regeneration ◽  
Experimental Conditions ◽  
Microbial Decomposition

AbstractThe exoskeleton of most invertebrate larval forms is made of chitin, which is a linear polysaccharide of β (1→4)-linked N-acetylglucosamine (GlcNAc) residues. These larval forms offer extensive body surface for bacterial attachment and colonization. In nature, degradation of chitin involves a cascade of processes brought about by chitinases produced by specific bacteria in the marine environment. Microbial decomposition of larval carcasses serves as an alternate mechanism for nutrient regeneration, elemental cycling and microbial production. The present study was undertaken to assess the influence of chitinase enzyme on the degradation of the nauplii of barnacle, Balanus amphitrite. The survival and abundance of bacteria during the degradation process under different experimental conditions was monitored. To the best of our knowledge, no such study is conducted to understand the degradation of larval exoskeleton using chitinase and its influence on bacteria. An increase in the chitinase activity with increase in temperature was observed. Scanning electron micrographs of chitinase treated nauplii showed scars on the surface of the barnacle nauplii initially and further disruption of the exoskeleton was observed with the increase in the treatment time. Bacterial abundance of the chitinase treated nauplii increased with the increase in enzyme concentration. Pathogenic bacteria such as Vibrio cholerae, V. alginolyticus, V. parahaemolyticus which were initially associated with the exoskeleton were absent after chitinase treatment, however, Bacillus spp. dominated subsequent to chitinase treatment and this might have important implications to marine ecosystem functioning.

scholarly journals High Voltage Electric Discharge for Recovery of Chlorogenic Acid from Tobacco Waste

2021 ◽  
Vol 13 (8) ◽  
pp. 4481
Author(s):  
Marija Banožić ◽  
Antun Jozinović ◽  
Jovana Grgić ◽  
Borislav Miličević ◽  
Stela Jokić
Keyword(s):  
Chlorogenic Acid ◽  
Process Parameters ◽  
Electric Discharge ◽  
High Voltage ◽  
Treatment Time ◽  
Strong Dependence ◽  
Extraction Procedure ◽  
Polynomial Equation ◽  
Experimental Conditions ◽  
Tobacco Waste

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

scholarly journals Photocatalytic Treatment of Wastewater Containing Simultaneous Organic and Inorganic Pollution: Competition and Operating Parameters Effects

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 855
Author(s):  
Ahmed Amine Azzaz ◽  
Salah Jellali ◽  
Nasser Ben Harharah Hamed ◽  
Atef El Jery ◽  
Lotfi Khezami ◽  
...  
Keyword(s):  
Ultra Violet ◽  
Degradation Process ◽  
Molar Ratio ◽  
Experimental Conditions ◽  
Retention Capacity ◽  
Isotherm Study ◽  
Related Data ◽  
Ph Values ◽  
Pseudo Second Order ◽  
Maximum Retention

In the present study, methylene blue (MB) removal from aqueous solutions via the photocatalytic process using TiO2 as a catalyst in the presence of external ultra-violet light (UV) was investigated. The results of adsorption in the absence of UV radiation showed that adsorption reached an equilibrium state at 60 min. The experimental kinetic data were found to be well fitted by the pseudo-second-order model. Furthermore, the isotherm study suggested that dye uptake by TiO2 is a chemisorption process with a maximum retention capacity of 34.0 mg/g. The photodegradation of MB was then assessed under various experimental conditions. The related data showed that dye mineralization decreased when dye concentrations were increased and was favored at high pH values and low salt concentrations. The simultaneous presence of organic and inorganic pollution (Zinc) was also evaluated. The effect of the molar ratio Zn2+/MB+ in the solution at different pH values and NaCl concentrations was also monitored. The corresponding experimental results showed that at low values of Zn2+ in the solution (30 mg/L), the kinetic of the MB removal became faster until reaching an optimum at Zn2+/MB+ concentrations of 60/60 mg/L; it then slowed down for higher concentrations. The solutions’ carbon contents were measured during the degradation process and showed total mineralization after about 5 h for the optimal Zn2+/MB+ condition.

scholarly journals Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Process ◽  
Light Irradiation ◽  
Enhancement Effect ◽  
Electron Hole ◽  
Experimental Conditions ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

Effect of pasteurization at 76 and 63 °C on the absorption of colostral IgG in calves

2000 ◽  
Vol 67 (4) ◽  
pp. 619-623 ◽  
Author(s):  
JEFF W. TYLER ◽  
JEFF LAKRITZ ◽  
DOUGLAS E. HOSTETLER ◽  
VICTORIA DOUGLAS ◽  
DUSTY M. WEAVER ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Adult Life ◽  
Disease Status ◽  
Heat Treating ◽  
Passive Transfer ◽  
Experimental Conditions ◽  
Biological Behaviour ◽  
Critical Determinant ◽  
Calf Health ◽  
Potential Disadvantage

The timely ingestion and absorption of colostral immunoglobulin is a critical determinant of neonatal calf health. Calves are born without appreciable concentrations of the serum immunoglobulins needed to protect against pathogenic bacteria, viruses and protozoa (Tyler & Parish, 1995). The beneficial effect of passive transfer of colostral immunoglobulin also extends beyond the neonatal period and persists into juvenile and adult life (Robison et al. 1988; Tyler et al. 1998; DeNise et al. 1989). Calves with failure of passive transfer, defined as serum protein < 50 g/l or serum IgG < 10 g/l, have increased mortality risks that persist until 10 weeks of age (Tyler et al. 1998).Several diseases are potentially spread by the ingestion of colostrum, including bovine leukosis and Johne's disease (Perrin & Polack, 1988; Streeter et al. 1995). In one study 22% of latently infected cows were demonstrated to shed Mycobacterium paratuberculosis in their colostrum (Streeter et al. 1995). Optimal programmes to prevent and eradicate these diseases generally include the provision that calves are given colostrum derived from cows of known negative disease status. Pasteurization or heat treatment of colostrum may provide a mechanism whereby calves are provided with protection against neonatal disease without creating undue potential for infection by chronic, economically relevant diseases.Attempts to heat disinfect colostrum are common in goat herds (MacKenzie et al. 1987). Pasteurization has been demonstrated to be effective against the caprine arthritis–encephalomyelitis virus (Adams et al. 1983; MacKenzie et al. 1987). Although Myco. paratuberculosis appears to resist pasteurization, this form of processing has been demonstrated to decrease the likelihood of positive colostral cultures for Myco. paratuberculosis under experimental conditions (Meylan et al. 1996). Sterilizing the milk and colostrum given to calves is a logical and reasonable strategy to prevent transmission of infectious microorganisms. The potential disadvantage of heat treating colostrum is that the immunoglobulins in colostrum may become denatured (Smith & Sherman, 1994). Pasteurization causes only a slight decrease in the colostral concentration of IgG in cattle (Meylan et al. 1996); however, the biological behaviour of these pasteurized immunoglobulins has not been critically examined. Therefore, we cannot be completely confident that immunoglobulin absorption, persistence in serum and biological activity are unchanged by this processing.The goal of this study was to determine the effect of pasteurization at 76 and 63 °C on the absorption of IgG from colostrum. Should these procedures decrease immunoglobulin absorption, the use of pasteurization in disease eradication programmes would require increased efforts to optimize the passive transfer of immunoglobulin.

Functionalization of Graphene with O and S for Catalytic Degradation of Chlorophenols and Dyes

2021 ◽  
Vol 1019 ◽  
pp. 194-204
Author(s):  
S. Sudhaparimala ◽  
R. Usha
Keyword(s):  
Graphene Oxide ◽  
Organic Dyes ◽  
Analytical Techniques ◽  
Degradation Process ◽  
Experimental Conditions ◽  
Photocatalytic Application ◽  
Wide Range ◽  
Doped Graphene ◽  
The Given ◽  
Graphene Structures

Graphene, functionalized with the heteroatoms like nitrogen, oxygen and sulphur atoms has been well explored for a wide range of applications but only few reports are available on its adsorption and photocatalytic application in the degradation of chlorophenols and organic dyes. A simple and energy-efficient process to prepare graphene oxide and sulphur doped graphene oxide was developed. The micro structure and surface morphology were confirmed by the analytical techniques of Powder X-ray diffractogram (PXRD), Fourier Transformed Raman Spectroscopy (FT-Raman), Scanning Electron Microscopy. The results were suggestive of the structures suitable for screening their catalytic activity in the degradation of the highly toxic polychlorophenols and organic dyes. The adsorption and photo catalytic properties of the asprepared samples were screened for the degradation process and it was found that sulphur doped graphene oxide showed more positive results for the degradation of chlorophenols than graphene oxide. Under the given experimental conditions the decoloration of dyes were not satisfactory. Ultimately, the study provided an economical and efficient, method for tuning graphene structures for the removal of pollutants in wastewater.

Optimization of Agar Preparation Based on Transparency

2021 ◽  
Vol 1033 ◽  
pp. 103-108
Author(s):  
Ying Cai ◽  
Zhan Xia Wu ◽  
Zhao Yu Zhang ◽  
Zhang Hu
Keyword(s):  
Activated Carbon ◽  
Treatment Time ◽  
Orthogonal Experiment ◽  
Economic Benefits ◽  
Experimental Results ◽  
Practical Significance ◽  
Process Conditions ◽  
Processing Temperature ◽  
Experimental Conditions ◽  
Filtration Method

To meet the requirement for high transparency of agar gel used in tissue culture, bacteriological applications, and high-quality cosmetics and food, this study on improving the transparency of agar products was carried out by using activated carbon for decolorization and perlite for aiding filtration. The results showed that the pre-coating filtration method was better than that of the mixed slurry filtration, so an orthogonal experiment optimization was conducted using the pre-coating filtration method based on the single factor experimental results. The experimental results showed that the optimal process conditions based on the transparency index were: concentration of agar of 1.30%, activated carbon dosage of 0.80%, processing temperature of 95 °C, and treatment time of 20 min. Agar products with gel transparency of 58.93% and blue-ray whiteness value of 93.82 could be obtained under these experimental conditions. The order of the factors influencing the decolorization ratio of agar was as follows: activated carbon dosage > concentration of agar > processing temperature > treatment time. The experimental results provided effective procession methods for the production enterprises based on transparency and increased economic benefits, and it was of practical significance.

scholarly journals Principles to enable comprehensive national marine ecosystem status assessments from disparate data: The state of the marine environment in Kuwait

2019 ◽  
Vol 230 ◽  
pp. 106407 ◽  
Author(s):  
Michelle J. Devlin ◽  
Brett P. Lyons ◽  
John Bacon ◽  
Nathan Edmonds ◽  
Dieter Tracey ◽  
...  
Keyword(s):  
Marine Environment ◽  
Marine Ecosystem ◽  
The State ◽  
Disparate Data

scholarly journals Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

2020 ◽  
Vol 14 (4) ◽  
pp. 1347-1383 ◽  
Author(s):  
Mark J. Hopwood ◽  
Dustin Carroll ◽  
Thorben Dunse ◽  
Andy Hodson ◽  
Johnna M. Holding ◽  
...  
Keyword(s):  
Primary Production ◽  
Case Studies ◽  
Marine Environment ◽  
Ocean Circulation ◽  
Marine Ecosystem ◽  
Freshwater Discharge ◽  
The Arctic ◽  
Temporal Region ◽  
Marine Biogeochemistry ◽  
Spatio Temporal

Abstract. Freshwater discharge from glaciers is increasing across the Arctic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier–ocean interactions in recent years, especially with respect to fjord/ocean circulation, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing the importance of glaciers for the marine ecosystem, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Kangerluarsuup Sermia/Bowdoin Fjord, Young Sound and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord–shelf exchange, nutrient availability, the carbonate system, the carbon cycle and the microbial food web are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating), fjord–glacier geometry and the limiting resource(s) for phytoplankton growth in a specific spatio-temporal region (light, macronutrients or micronutrients). Arctic glacier fjords therefore often exhibit distinct discharge–productivity relationships, and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems.

Waste Biomass from Marine Environment as Arsenic and Lead Biosorbent

2009 ◽  
Vol 71-73 ◽  
pp. 597-600 ◽  
Author(s):  
F. Beolchini ◽  
C. Pennesi ◽  
B. Testaferri ◽  
C. Totti ◽  
I. De Michelis ◽  
...  
Keyword(s):  
Marine Environment ◽  
Red Algae ◽  
Strong Dependence ◽  
Experimental Tests ◽  
Waste Biomass ◽  
Lead Uptake ◽  
Experimental Conditions ◽  
Arsenic Uptake ◽  
Metal Biosorption ◽  
Suspended Biomass

This paper deals with arsenic and lead biosorption by different waste biomasses coming from the marine environment. Shoreline seaweeds and seagrasses were used to adsorb metals from aqueous solutions, under different pH. Experimental tests were performed in order to study the equilibrium of biosorption with suspended biomass. The obtained results confirmed the possibility of using marine macrophyte biomass for heavy metal biosorption and evidenced a strong dependence of lead and arsenic uptake on the macrophyte structure. Brown algae were found to be the best sorbents for lead with a maximum observed lead uptake of 140 mg/g; green algae showed a maximum lead uptake in the range 50-70 mg/g; red algae were the worst lead sorbent, in the investigated experimental conditions, with a maximum lead uptake in the range 10-40 mg/g. As concerns arsenic, the macrophytes had in general good sorption abilities when compared with those of activated carbon. Furthermore red algae, that for lead were not effective, resulted to be the best sorbents for arsenic. This was explained by a different speciation in aqueous solution of lead (II), that is cationic with respect to arsenic(V), that is anionic.

Development of a Microwave Treatment Technique for Bacterial Decontamination of Raw Meat

2008 ◽  
Vol 4 (3) ◽  
Author(s):  
Yury Shamis ◽  
Alex Taube ◽  
Yury Shramkov ◽  
Natasa Mitik-Dineva ◽  
Barbara Vu ◽  
...  
Keyword(s):  
High Frequency ◽  
Pathogenic Bacteria ◽  
Thermal Inactivation ◽  
Microwave Treatment ◽  
Treatment Technique ◽  
Single Exposure ◽  
Experimental Conditions ◽  
Lethal Temperatures ◽  
And Staphylococcus Aureus ◽  
Raw Meats

The present study developed and verified a 'cold' microwave (MW) treatment that could lead to the inactivation of two common pathogenic species of bacteria, Escherichia coli and Staphylococcus aureus, in raw meats. A number of experimental conditions were designed and tested to maximise MW exposure without overheating the samples. The non-thermal effect was maximised by multiple exposure to attain efficient MW threshold intensities. It was shown that at sub-lethal temperatures repeated exposure using high frequency MW radiation was significantly more effective in decontaminating bacteria in raw meats compared to a single exposure. It was concluded that non thermal inactivation of pathogenic bacteria in raw meats could be achieved at defined conditions using high frequency MW radiation.

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