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At least 253 records · Page 14Linked to original sources

PubMed1988

Flow cytometric measurement of pollutant stresses on algal cells.

The lichen Usnea fulvoreagens (Räs). Räs. was treated with four pH levels (5.5, 4.5, 3.5, and 2.5) of simulated acid rain (sulfuric acid, nitric acid, and a 1:1 combination of both) and automobile exhaust. The samples were dissociated and analyzed by a Becton-Dickinson FACS 440 flow cytometer. Analyses included measurement of chlorophyll autofluorescence and fluorescence due to uptake of fluorescein diacetate (FDA) and calcofluor white M2R (CFW). Cell parameters measured were esterase activity (FDA), membrane permeability (FDA, CFW), and intracellular pH (FDA). Mean fluorescence intensity from FDA staining and numbers of events were incorporated with autofluorescence information to produce a "stress index" of relative cell stress. Results indicated that highly stressed samples (lower pH treatments and greater exposure to exhaust) exhibited a low "stress index" of FDA fluorescence.

Cell Separation↗

PubMed1995

Effect of titanium surface roughness on proliferation, differentiation, and protein synthesis of human osteoblast-like cells (MG63).

The effect of surface roughness on osteoblast proliferation, differentiation, and protein synthesis was examined. Human osteoblast-like cells (MG63) were cultured on titanium (Ti) disks that had been prepared by one of five different treatment regimens. All disks were pretreated with hydrofluroic acid-nitric acid and washed (PT). PT disks were also: washed, and then electropolished (EP); fine sandblasted, etched with HCl and H2SO4, and washed (FA); coarse sandblasted, etched with HCl and H2SO4, and washed (CA); or Ti plasma-sprayed (TPS). Standard tissue culture plastic was used as a control. Surface topography and profile were evaluated by brightfield and darkfield microscopy, cold field emission scanning electron microscopy, and laser confocal microscopy, while chemical composition was mapped using energy dispersion X-ray analysis and elemental distribution determined using Auger electron spectroscopy. The effect of surface roughness on the cells was evaluated by measuring cell number, [3H]thymidine incorporation into DNA, alkaline phosphatase specific activity, [3H]uridine incorporation into RNA, [3H]proline incorporation into collagenase digestible protein (CDP) and noncollagenase-digestible protein (NCP), and [35S]sulfate incorporation into proteoglycan. Based on surface analysis, the five different Ti surfaces were ranked in order of smoothest to roughest: EP, PT, FA, CA, and TPS. A TiO2 layer was found on all surfaces that ranged in thickness from 100 A in the smoothest group to 300 A in the roughest. When compared to confluent cultures of cells on plastic, the number of cells was reduced on the TPS surfaces and increased on the EP surfaces, while the number of cells on the other surfaces was equivalent to plastic. [3H]Thymidine incorporation was inversely related to surface roughness. Alkaline phosphatase specific activity in isolated cells was found to decrease with increasing surface roughness, except for those cells cultured on CA. In contrast, enzyme activity in the cell layer was only decreased in cultures grown on FA- and TPS-treated surfaces. A direct correlation between surface roughness and RNA and CDP production was found. Surface roughness had no apparent effect on NCP production. Proteoglycan synthesis by the cells was inhibited on all the surfaces studied, with the largest inhibition observed in the CA and EP groups. These results demonstrate that surface roughness alters osteoblast proliferation, differentiation, and matrix production in vitro. The results also suggest that implant surface roughness may play a role in determining phenotypic expression of cells in vivo.

Alkaline Phosphatase↗

PubMed2001

Study of an Au colloid self-assembled electrode and its application to the determination of carbon monoxide.

A novel electrochemical sensor has been developed for the detection of carbon monoxide. The chemically modified electrode, prepared by reaction of cysteine and then an Au colloid of size approximately 15 nm with a platinum microelectrode, has excellent catalytic activity toward carbon monoxide, with an oxidation potential of +600 mV relative to the Ag/AgCl electrode. The CO gas sensor is based on an Au colloid self-assembled modified electrode as working electrode, an Ag/AgCl electrode as reference electrode, a Pt electrode as counter electrode, and a porous film which is in direct contact with the gas-containing atmosphere. The effects on the determination of CO of different internal electrolyte solutions of perchloric acid, hydrochloric acid, sulfuric acid, nitric acid, and phosphate buffer of different concentrations were also studied. The sensor is characterized by a short response time and highly reproducible detection of CO. This sensor can be used in the field of environmental monitoring and control.

Calibration↗

PubMed2005

Changes in cell wall polysaccharides in developing barley (Hordeum vulgare) coleoptiles.

Cell wall polysaccharides in developing barley coleoptiles were examined using acetic acid-nitric acid extraction, alditol acetate and methylation analyses and enzymatic digestion. The coleoptile cell wall from imbibed grain was rich in pectic polysaccharides (30 mol%), arabinoxylan (25 mol%), cellulose (25 mol%) and xyloglucan (6 mol%), but contained only low levels of (1-->3,1-->4)-beta-D-glucan (1 mol%). During 5 days of coleoptile growth, pectic polysaccharides decreased steadily to about 9 mol%, while (1-->3,1-->4)-beta-D-glucan increased to 10 mol%. Following the cessation of growth of the coleoptiles at about 5 days, (1-->3,1-->4)-beta-D-glucan content rapidly decreased to 1 mol%. The cellulose content of the walls remained at about 35-40 mol% throughout coleoptile growth. Similarly, arabinoxylan content remained essentially constant at 25-30 mol% during growth, although the ratio of substituted to unsubstituted 4-linked xylosyl units decreased from about 4:1 to 1:1. Xyloglucan content ranged from 6 mol% to 10 mol% and the oligosaccharide profile determined using a xyloglucan-specific endoglucanase and MALDI-TOF mass spectrometry indicated that the oligosaccharides XXGG and XXGGG were the principal components, with one and two acetyl groups, respectively, Thus, dramatic changes in wall composition were detected during the growth of barley coleoptiles, both with respect to the relative abundance of individual wall constituents and to the fine structure of the arabinoxylans.

Cell Wall↗

PubMed2004

Epidemiology of 377 patients with chemical burns in Guangdong province.

A total of 377 patients with chemical burns from all over Guangdong province were admitted to the Guangzhou Red Cross Hospital during the period from January 1987 to December 2001. There were 296 males and 81 females with a male to female ratio of 3.65:1. The mean age of the patients was 26 years. The majority of patients (89.2%) were in the age range of 15-60 years. Professionally, 244 patients (64.7%) were workers, of whom, 232 (95%) of patients were peasant workers. Most of the chemical burns occurred at places away from home (94.4%), especially in the working environment (67.8%). Only 20 patients (5.5%) were injured at home. Chemical burns by accident and by criminal assault were 337 (88.5%) and 40 (10.5%). Strong acids (60.8%), mainly sulfuric acid, nitric acid, hydrofluoric acid, alkali (33.9%), mainly lime and sodium hydroxide were common causative agents. There was a relationship between the incidence of chemical burns and the season, with more patients in July-September and October-December. There were 215 (57.1%) patients who washed the burnsite with water immediately, but the volumes of water and time of washing were not adequate. Patients with total burn surface area (TBSA) of less than 10% comprised the majority of patients (72.7%), with 188 (65.7%) deep partial thickness burns, 116 (40.6%) with full thickness burns, and 60 (21%) with superficial burns. Extremities (lower limb 56.6% and upper limb 51.4%) were the most frequent area of injury. Ocular burns were the most common accompanying injury (14.7%). Operations of autografts and conjunctival flap were carried out on 159 (42.2%) patients. The average period of hospitalization was 22 days. Only 2 (0.7%) deaths occurred in this study. Counter measures to improve this situation must include safety productive education and professional training, use of protective clothing at work, enhancing the concept of legal responsibility, and restricting management and use of corrosive chemicals. Irrigation of the burnsite promptly with substantial volumes of water and an adequately long time will help reduce the morbidity from chemical burns.

Adolescent↗

PubMed1997

Biosorption of lead and zinc from solutions using Streptoverticillium cinnamoneum waste biomass.

Mycelial wastes of microbial origin from fermentation industries have been recognized as potential biosorbents for decontamination of waste waters containing heavy metals. Dried, nonliving, granulated biomass of Streptoverticillium cinnamoneum was used for the recovery of lead and zinc from solutions. It was found that pretreatment of the biomass with boiling water for 15 min increased the biosorption of lead and zinc by 52 and 41%, respectively. The optimum pH range for lead uptake was 3.5-4.5 while for zinc it was 5.0-6.0. The lead and zinc adsorption data when applied to Freundlich and Langmuir isotherm equations showed good correlation (r2 = 0.97) and hence equal conformity to both models. The Scatchard plots indicated clearly that more than one type of binding sites were involved in the adsorption of lead and zinc by the biomass. The maximum loading capacity of S. cinnamoneum biomass was found to be 57.7 mg/g for lead and 21.3 mg/g for zinc with boiling water pretreatment. The loaded metals could be desorbed effectively with dilute hydrochloric acid, nitric acid and 0.1 M EDTA. Treatment with 0.1 M sodium carbonate permitted reuse of the desorbed biomass although the metal loading capacity in the subsequent cycles decreased by 14-37%. The metal biosorbent granules prepared are a value-added product that has the potential for removal/recovery of lead and zinc from dilute solutions on a commercial scale.

Adsorption↗

PubMed1990

Mechanism of acid-induced folding of proteins.

We have previously shown [Goto, Y., Calciano, L. J., & Fink, A. L. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 573-577] that beta-lactamase, cytochrome c, and apomyoglobin are maximally unfolded at pH 2 under conditions of low ionic strength, but a further decrease in pH, by increasing the concentration of HCl, refolds the proteins to the A state with properties similar to those of a molten globule state. To understand the mechanism of acid-induced refolding of protein structure, we studied the effects of various strong acids and their neutral salts on the acid-unfolded states of ferricytochrome c and apomyoglobin. The conformational transition of cytochrome c was monitored at 20 degrees C by using changes in the far-UV CD and in the Soret absorption at 394 nm, and that of apomyoglobin was monitored by changes in the far-UV CD. Various strong acids (i.e., sulfuric acid, perchloric acid, nitric acid, trichloroacetic acid, and trifluoroacetic acid) refolded the acid-unfolded cytochrome c and apomyoglobin to the A states as was the case with HCl. For both proteins neutral salts of these acids caused similar conformational transitions, confirming that the anions are responsible for bringing about the transition. The order of effectiveness of anions was shown to be ferricyanide greater than ferrocyanide greater than sulfate greater than thiocyanate greater than perchlorate greater than iodide greater than nitrate greater than trifluoroacetate greater than bromide greater than chloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Effects of decalcification on immunoperoxidase staining.

One of the limitations of immunoperoxidase methods applied in surgical pathology is the loss of immunoreactivity during fixation and processing. In this study, the effects of decalcification on the immunoreactivity of various antigens in formalin fixed tissues were examined. The pieces of fixed tissue were placed in four different decalcifying solutions (EDTA, formic acid, nitric acid, and Plank-Rychlo solution) for various time periods and then processed routinely and embedded in paraffin. The paraffin sections of the tissues were stained with immunoperoxidase methods for immunoglobulins, hormones, or tissue/tumor-specific markers. Sections of nondecalcified tissues were used as a control. The immunohistochemical staining intensity and the number of positive cells were not reduced significantly in decalcified tissues within the usual time period of routine decalcification procedures. Many antigens survived even prolonged decalcification. The results of this study indicate that routinely decalcified tissues can be used for immunoperoxidase staining without significant loss of immunoreactivity.

Decalcification Technique↗

PubMed1995

Determination of lead, cadmium, mercury, and copper concentrations in duck eggs in Taiwan.

Samples of duck eggs were collected from 65 farms distributed in 6 counties in Taiwan to analyze the contents of Pb, Cd, Hg, and Cu in albumen and yolk. Lead, Cd, and Cu determinations were performed by microwave digestion together with atomic absorption spectrophotometry, whereas Hg was analyzed by sulfuric acid-nitric acid digestion and cold vapor atomic absorption spectrophotometry. Expressed on a wet weight basis, the average concentrations (ranges) of the four metals were as follows: Pb, 13.6 ng/g (.8 to 27.5) in albumen and 84.7 ng/g (44.8 to 224.7) in yolk; Cd, 1.8 ng/g (< .5 to 4.4) in albumen and 3.8 ng/g (< 1.0 to 5.7) in yolk; Hg, 17.8 ng/g (2.5 to 47.5) in albumen and 9.7 ng/g (1.2 to 20) in yolk; Cu, .83 micrograms/g (.56 to 1.08) in albumen and 1.36 micrograms/g (.95 to 1.95) in yolk. Comparison of the calculated daily intakes of Pb, Cd, and Hg from eggs with the World Health Organization-Food Agriculture Organization provisional tolerated daily intakes suggest that duck eggs are safe with respect to the contents of the three metals. Eggs are poor sources of Cu, supplying less than 2% of the Recommended Dietary Allowance.

Animals↗

PubMedDate not supplied

Supported liquid membrane stability in chiral resolution by chemically and physically modified membranes.

In the present work some stability studies on Supported Liquid Membranes (SLMs) to be used for chiral separations were realized. In particular, primary aim was to determine how a modification of the support surface influences the SLM stability. First, the procedure for support modification was optimised, making a screening of various compounds (sulphuric acid, nitric acid, chromic acid, sodium dodecyl sulphate (SDS), glycerol, oleic alcohol, propylene glycol (PPG), bovine serum albumin (BSA)) and testing their performance by means of contact angle measurements. Next, a second screening was realized by permeation tests in a stirred cell. Finally, to compare the stability of modified with unmodified support in a process of interest for chemical and/or biochemical industries, some permeation tests for resolution of DNB-DL-Leucine were realized in a re-circulation system. Results showed a better surface hydrophilization of chemically modified support and better stability of the sulphonated support. However, in operating conditions a little high stability of the unmodified support was obtained.

Filtration↗

PubMed1985

Acute poisoning by selenious acid.

A 2 yo male child ingested approximately 15 ml of a Gun Blue solution containing selenious acid, nitric acid and copper nitrate. He was immediately given milk and vomited spontaneously blood-stained food with a garlic smell. He was admitted to our Centre less than 3 hr following ingestion. An esophago-gastroscopy showed a second degree burn of both esophagus and stomach. He became comatose and had to be ventilated mechanically. Metabolic acidosis, leucocytosis, hyperglycemia and hemoconcentration were also observed. During the following day he developed a severe intestinal distension, a cardiomyopathy (CPK = 1,302, cardiac arrhythmia), and moderate hepatic, renal and pulmonary dysfunctions. Plasma selenium concentration was 285 micrograms/L and the maximum urinary concentration was 28,459 micrograms/L. After 4 days, his condition had improved considerably and he was about to be extubated when he suddenly developed acute respiratory distress. A similar episode occurred 24 hr later. His lung function progressively deteriorated; later he required the use of an extracorporeal membrane lung. Legionella dumofii was found the causative agent. He died 17 d after ingestion despite aggressive treatment. Acute selenious acid poisoning and its relation to Legionnaire's disease is discussed.

Acid-Base Imbalance↗

PubMed2005

[Safety destruction of tetramethylene disulfotetramine and its medical waste].

OBJECTIVE: To develop suitable methods for safety destruction of tetramethylene disulfotetramine (TETS) and the medical wastes polluted by TETS. METHODS: The chemical stability of TETS was evaluated under the conditions of acid, alkali and high temperature. TETS was treated with sodium hydroxide, hydrochloric acid, sulfuric acid and nitric acid under various treatment conditions, i.e. concentration, temperature and time, followed by determining remaining TETS using gas chromatograms to estimating the degradation efficiency of TETS. TETS was put into ampoule and heated under the different conditions of temperature and time. After heat treatment, TETS residue was determined. For evaluating the absorption factor of active carbon to TETS in water and blood, active carbon was added into the water and blood with content of TETS, incubated at room temperature for 24 hours, and then determined the remaining TETS in water and blood. RESULTS: The complete degradation of TETS was achieved by one of the following treatments: heating with 6.0 mol/L hydrochloric acid at 100 degrees C for half an hour, heating with 3.0 mol/L hydrochloric acid or 6.0 mol/L sodium hydroxide at 100 degrees C for 3 hours, mixing with concentrated sulfuric acid or nitric acid at room temperature for 24 hours, and dry heating at 300 degrees C for 4.5 hours. Active carbon showed a marked effectiveness in absorbing the TETS in blood and water, with the mean absorption efficiency of over 90%. CONCLUSIONS: The results of this study suggest that TETS powder should be degraded by acid or alkali, and that the solid medical wastes polluted by TETS should be destroyed at high temperature. For the blood and water having contents of TETS, the active carbon should be used as to absorbing the TETS and then be destroyed at high temperature.

Bridged-Ring Compounds↗

PubMed2004

Comparative study of crude and purified cellulose from wheat straw.

A sequential totally chlorine-free procedure for isolation of cellulose from wheat straw was proposed in this study. The dewaxed straw was pretreated with 0.5 M NaOH in 60% methanol at 60 degrees C for 2.5 h under ultrasonic irradiation for 0-35 min and sequentially posttreated with 2% H(2)O(2)-0.2% TAED at pH 11.8 for 12 h at 48 degrees C, which together solubilized 85.3-86.1% of the original hemicelluloses and 91.7-93.2% of the original lignin, respectively. The yield of crude cellulose ranged between 46.2 and 49.2% on a dry weight basis related to wheat straw, which contained 11.2-12.2% residual hemicelluloses and 2.5-2.9% remaining lignin. Further treatment of the corresponding crude cellulosic preparations with 80% acetic acid-70% nitric acid under the condition given yielded 36.8-37.7% of the purified cellulose, which contained minor amounts of bound hemicelluloses (2.5-2.8%) and was relatively free of associated lignin (0.1-0.2%). The isolated crude and purified cellulose samples were comparatively studied by FT-IR and CP/MAS (13)C NMR spectroscopy, and the relative crystallinity was also estimated. The final stage treatment with 80% acetic acid-70% nitric acid decreased the hemicelluloses and lignin associated in the crude cellulose but led to 3.1-5.4% degradation of the original cellulose; in addition, the purity of the obtained cellulose was high. However, it was found that the final stage treatment is not severe enough to cause decrystallization of cellulose. The thermal stability of the purified cellulose is higher than that of the corresponding crude cellulose.

Cellulose↗

PubMed2000

[Determination of eight impurity elements in organic dye oil red by ICP-AES].

Simultaneous determination of metal impurities of Fe, Al, Cu, Pb, Zn, Cr, Mn and Ti in organic dye oil red by inductively coupled plasma atomic emission spectrometry (ICP-AES) is presented in this paper. Different sample digestion procedures were compared, and methods for the elimination of spectrum interference were investigated. The proposed sample digestion procedure includes charring with concentrated sulfuric acid and nitric acid, cineration at 500 degrees C, and step-wisely extracting the residue with hydrochloric acid plus peroxide of hydrogen, and hydrochloric acid plus nitric acid (VHCl:VHNO3 = 1:1). The detection limits are 0.15 mg.L-1 for Fe, 1.7 x 10(-2) mg.L-1 for Al, 5.0 x 10(-3) mg.L-1 for Cu, 0.20 mg.L-1 for Pb, 2.7 x 10(-2) mg.L-1 for Zn, 5.7 x 10(-3) mg.L-1 for Cr, 1.3 x 10(-3) mg.L-1 for Mn, 2.1 x 10(-3) mg.L-1 for Ti, respectively. The precision of the method is in the range of 0.8%-21.5% (n = 5), and recovery in the range of 84.6%-118.6%.

English Abstract↗

PubMed1987

Acid rain: effects on arachidonic acid metabolism in perfused and ventilated guinea-pig lung.

Isolated, perfused and ventilated guinea-pig lungs were exposed for 10 min to acid (sulphuric + nitric acid) aerosol mimicking acid rain at pH 4.5 or 2.5, as well as to a control distilled water aerosol (pH 6.0-6.5). Lung perfusing solution was recovered and thromboxane (TX) B2 and leukotriene (LT) B4 were measured by radioimmunoassay (RIA) techniques. In a series of experiments TXB2 release averaged 0.43 +/- 0.18 (+/- SD) ng/min during exposure to distilled water aerosol and increased to 0.70 +/- 0.30 ng/min during exposure to acid aerosol at pH 4.5 (P less than 0.05). In a second series of experiments TXB2 release was 0.46 +/- 0.18 ng/min and increased to 1.07 +/- 0.51 ng/min (P less than 0.01) after acid aerosol at pH 2.5. In both cases LTB4 release, reflecting lipoxygenase activity, was unchanged. LTC4 levels were not measurable under basal conditions as well as after exposure to acid aerosol. A pneumoconstriction was also observed, being more pronounced after acid aerosol at pH 2.5. Individual sulphuric and nitric acid aerosol component solutions at pH 2.5 evoked TXB2 and airway resistance changes corresponding to those observed with the mixed acid aerosol. LTB4 was not modified. Acid rain inhalation may directly stimulate pathways leading to the bronchoconstrictor and pro-aggregating TXA2 synthesis in isolated guinea-pig lung, without affecting the lipoxygenase pathway of arachidonic acid metabolism.

Aerosols↗

PubMed2003

Electrochemical remediation of copper contaminated kaolinite by conditioning anolyte and catholyte pH simultaneously.

This report examined electrochemical remediation of copper contaminated kaolinite by controlling electrolytes' pH for both of anolyte and catholyte simultaneously. Results showed that electrokinetic process and remediation efficiency varied obviously when different buffer systems, including citric acid (test 1 ) nitric acid + EDTA (test 2) and nitric acid (test 3), were used to control catholyte pH and Na2CO3 was used at the same time to control all anolyte one. It was found that under such pH condition soil's pH in soil column kept at 3.0-7.0 successfully, and correspondingly no copper precipitation and decrease of soil electroconductivity appeared, which are usually observed in electrokinetic process due to OH- introduction into soil column by electrochemical reaction occurred in cathode. Electroosmosis flow rates were almost equal for these three tests, indicating that these buffers did not affect Zeta-potential of kaolinite within the examined duration. More acid and basic solution was added into electrokinetic cell when nitric acid was used as buffer than when nitric acid + EDTA and then citric acid were used. Due to introduction of large amounts of ions into soil column, significant higher current was observed for test 3 than other two. Analysis of copper speciation and total quantity in kaolinite indicated that 22.5%, 23.74% and 55.65% Cu were removed from kaolinite for test 1, test 2 and test 3 respectively after only 10 days' electrokinetic remediation.

Chelating Agents↗

PubMed2006

Digestion of plastic materials for the determination of toxic metals with a microwave oven for household use.

A rapid sample-digestion method for the determination of toxic metals, cadmium, chromium, and lead, in polyethylene and polyvinyl chloride has been developed by using a microwave oven for household use. An appropriate amount of the sample taken in a PTFE decomposition vessel was mixed with nitric acid or nitric and sulfuric acids. The vessel was heated in a microwave oven by a predetermined operating program. The digested sample was diluted to a definite volume with water after evaporating most of the nitric acid. The precipitate, if formed, was filtered off by a membrane filter. The metals were determined by ICP-AES. The sample digestion required 5 min (for 20-mg sample) to 25 min (for 60-mg sample). The analytical results obtained for cadmium, chromium, and lead in a polyethylene certified reference material, BCR-680, digested with nitric acid, were in good agreement with the certified values.

Cadmium↗

PubMed2006

Evaluation of four digestive methods for extracting diatoms.

OBJECTIVE: To compare the merit of four digestive methods (nitric acid plus hydrogen peroxide, proteinase K, nitric acid in Disorganization Can and Soluene-350) for extracting diatoms in order to choose the best digestive method for the diagnosis of drowning. METHODS: Liver, kidney and bone marrow of rabbits were minced and then digested by four digestive methods separately with the following indices compared: (1) time demanded for complete digestion; (2) degree of digestion for different tissues; (3) the reclaiming ratio of diatoms; (4) the degree of digestive destruction to diatoms. RESULTS: For sufficiently digesting the same tissue, the demanded times for the different methods ranked from the longest to the shortest were as follows: Soluene-350, proteinase K, nitric acid plus hydrogen peroxide, nitric acid in Disorganization Can. Nitric acid in Disorganization Can method and nitric acid plus hydrogen peroxide method digested the tissues more thoroughly than proteinase K, than Soluene-350 methods. For Cyclotella and Cybella, proteinase K method reclaimed most diatoms and nitric acid plus hydrogen peroxide method reclaimed less, while nitric acid in Disorganization Can and Soluene-350 methods reclaimed the least. For Navicula, the majority of diatoms could be extracted using proteinase K method, but only a few diatoms with other three methods. Under scanning electron microscopy (SEM), the structure of diatoms remained almost perfect after digestion with proteinase K, but destroyed to some extent with other three methods. CONCLUSION: This study demonstrated that different diatoms (in fresh or sea water) have different resistance to different digestive reagents. As far as the reliability and applicability of the diatom test is concerned, proteinase K method is of the best choice, nitric acid plus hydrogen peroxide can be its substitute. Soluene-350 cannot be used for extracting sea water diatoms.

Animals↗