Yolk Emulsion Research Articles

Destabilization of Egg Yolk Emulsion After IgY Removal Through Enzymatic Treatments

AbstractThe objective of this study was to destabilize the protein–lipid complex in egg yolk precipitate obtained after the removal of soluble proteins, referred to as the pellet, through enzymatic treatment for further phospholipids extraction. A combination of proteolytic and lipolytic enzymes was applied to release the lipids from the pellet or weaken the pellet emulsion. Emulsions prepared using Protease P/Lipase AY30, Protease II/Lipase AY30 and Protease M/Lipase AY30 treated pellets had larger oil droplets (78, 65, 56 µm) and higher coalescence rates (51, 41, 35 %) than those of Protex 51FP, pellet, Protex 7L and Protease A with oil droplet size of 20, 18, 15 and 13 µm and coalescence rates of 31, 8, 7.5 and 8 %, respectively. Cream and liquid subnatant fractions obtained after further centrifugation of hydrolysates were subjected to lipid analyses. Over 90 % of phosphatidylcholine (PC) present in the pellet and 80 % of that in the original egg yolk were recovered in the cream from Protease P/Lipase AY30 treatment, while the recovery of PC from the egg yolk was significantly lower in creams from Protex 7L or Protease 51FP treatments (12 and 10 %, respectively). Pellets treated with Protease M, Protex 7L or Protex 51FP in combination with Lipase AY30 led to a significant loss of PC due to the conversion of PC to lysophosphatidylcholine or its degradation. Cream fractions obtained from the study represented a better material for the recovery of PL than intact egg yolk using environmentally‐friendly techniques such as supercritical carbon dioxide (SC‐CO2) extraction.

Detection of mechanism and anticancer activity of the new quinoline compounds MC20 and MC21*

s / Journal of Biotechnology 185S (2014) S37–S125 S93 III – left ear =3.61, wave V – left ear =3.15; dog 3: wave V – left ear =3.57, right ear =4.45). Conclusion: In congenital hydrocephalic dogs from this study, increased amplitudes of BAER waves III and V were observed. These changes are rare in BAER evaluations and can be explained by the inhibition of cortical auditory neurons or of descending auditory pathways. http://dx.doi.org/10.1016/j.jbiotec.2014.07.316 The optimization of isolating and identifying of Fusobacterium necrophorum species involved into sheep’s and cattle’s affections Laura Aneta Tudor1,∗, Paul Grigorescu1, Elena Mitranescu2, Laurentiu Tudor2 1 Faculty of Veterinary Medicine “Spiru-Haret” Bucharest, Romania 2 Faculty of Veterinary Medicine, Bucharest, Romania E-mail address: anetalauratudor@yahoo.com (L.A. Tudor). There have been effectuated comparatively investigations for isolating and identifying of Fusobacterium necrophorum species from many samples of necrotic-pus material harvested from sheep and cattle with different affections generated by this bacteria. For this scope, from the samples has been simultaneous inseminated on three different selective mediums: agar VL with horse blood, green brilliant and sodium azide; agar heart–brain with violet crystal, phenethyl-alcohol and yolk emulsion; agar heart–brain with horse blood, kanamycin and vancomycin. Following the effectuated researches, on agar VL with horse blood, green brilliant and sodium azide it has been isolated 24 F. necrophorum stems, on agar hearth-brain with violet crystal, phenethyl-alcohol and yolk emulsion it has been isolated 36 stems and 11 stems on agar heart–brain with horse blood, kanamycin and vancomycin. Based on the obtained results, we consider that the agar VL with horse blood, green brilliant and sodium azide is the most efficient for isolating and identifying the F. necrophorum species, presenting the advantage of faster growing up of colonies (48h maximum) comparatively of agar heart–brain with violet crystal, phenethylalcohol and yolk emulsion that make the colonies to be visible just after 72h of incubation. http://dx.doi.org/10.1016/j.jbiotec.2014.07.317 Detection of mechanism and anticancer activity of the new quinoline compounds MC20 and MC21* Tugba Kul Koprulu1,∗, Saban Tekin2, Salih Okten3, Merve Cinar4, Seda Duman5, Osman Cakmak4 1 Department of Biology, Gaziosmanpasa University, Faculty of Science & Art, Tokat, Turkey 2 Department of Molecular Biology & Genetics, Gaziosmanpasa University, Faculty of Science & Art, Tokat, Turkey 3 Primary Education, Division of Science Education, Faculty of Education, Kirikkale University, Kirikkale, Turkey 4 Department of Chemistry, Faculty of Art and Science, Yildiz Technical University, Davutpasa, Istanbul, Turkey 5 Departments of Chemistry, Gaziosmanpasa University, Faculty of Science & Art, Tokat, Turkey E-mail address: tugbakul koprulu@hotmail.com (T.K. Koprulu). Various quinoline compounds have received great attention due to their potent biological activities. The aim of this study was to investigate the anticancer properties and mechanism of action of the novel quinoline derivatives, MC20 and MC21. Antiproliferative and cytotoxic activities of MC20 and MC21 were tested on HeLa (human cervix carcinoma), HT29 (human colon carcinoma), and C6 (rat brain carcinoma) cell lines in vitro using BrdU cell proliferation ELISA, sulphorhodamine B (SRB), and lactate dehydrogenase (LDH) assay. The mechanism of anticancer activity of MC20 and 21 were determined using DNA laddering assay which indicates apoptosis. Results indicated that the new quinoline derivatives, MC20 andMC21weremore antiproliferative and cytotoxic against tumor cells than anticancer drug, 5-flourourasil (5-FU). MC20 and MC21 caused DNA laddering in tumor cells in DNA laddering assays, indicating that they prevent proliferation of tumor cells by inducing apoptosis. The results showed that the MC20 and MC21 are potential anticancer drug candidate with high antiproliferative activity on tumor cells in vitro. *This study is supported by a grant (TBAG 112T394) from TUBITAK. http://dx.doi.org/10.1016/j.jbiotec.2014.07.318 Diagnostic techniques performed before and after the ablation of a tumored prostate and urinary bladder in a dog Vulpe Vasile1,∗, Pasca Aurelian Sorin1, Vulpe Cristina Alice2, Papuc Ionel2 1 Department of Clinics, Veterinary Faculty, Agricultural Sciences and Veterinary Medicine, Iasi, Romania 2 Department of Doctoral Schools, Veterinary Faculty, Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania E-mail address: vasile vulpe@yahoo.com (V. Vasile). In dogs, the prostate can suffer various processes, such as hyperplasia or malignancy. The purpose of this paper is to underline the connection between the clinical and imaging diagnostic techniques and the surgical ones, while also preserving and ensuring the life of the patient. One Pekinese 14 year old dog was examined radio-

Indirect magnetic resonance imaging lymphography identifies lymph node metastasis in rabbit pyriform sinus VX2 carcinoma using ultra-small super-paramagnetic iron oxide.

BackgroundUSPIO is a contrast agent for MRI that can generate T2W images with low signal intensities. After subcutaneous or intravenous injection of USPIO, normal lymph node tissues uptake these nano-particles, but tumor cells do not. Thus, tumor metastasis can be detected using this contrast agent.ObjectiveThe aim of this study was to access the feasibility of USPIO enhanced MRI for the detection of cervical lymph node metastasis in a pyriform sinus carcinoma animal model and to investigate the ability of USPIO to enhance images of cervical lymph node metastases.Methods and FindingsTwenty New Zealand rabbits were randomly divided into tumor and inflammatory groups, and each group contained 10 rabbits. In the inflammatory group, a 0.5 ml egg yolk emulsion was injected into the sub-mandibular muscle of the rabbits to induce an inflammatory reaction in their cervical lymph nodes. In the tumor group, a VX2 tumor tissue suspension was transplanted into the pyriform sinus sub-mucosa of the rabbits using direct laryngoscope. Four weeks after the tumor or egg yolk injection, MRIs were performed before and after USPIO injection to observe the imaging enhancement features of USPIO. After that, a histo-pathological analysis was performed for all rabbits. We found the metastatic lymph nodes had no signal reduced intensity or irregular signal reduced intensity on T2-weighted image by using USPIO enhancement. In the tumor group,the sensitivity and specificity of plain MRI were 57.6% and 60.7%. The corresponding values of USPIO-enhanced MRl were 96.1% and 85.7%. (P<0.05)ConclusionThe features and the extent of the lymph node metastases corresponded to those observed on USPIO-enhanced MR images. USPIO-enhanced MRI is useful for the detection and estimation of lymph node metastasis in this cervical carcinoma animal model.

Characterization of Methicillin-Resistant Staphylococcus aureus in a Tertiary Care Teaching Hospital, South India

S. aureus causes superficial to deep seated infections in human beings. Methicillin-resistant Staphylococcus arueus (MRSA) evolved in the 1960s and since then has become a worldwide concern owing to increasing morbidity and mortality in health-care settings and even community. (MRSA) is a resistant variant of S. aureus which are resistant to beta-lactum antibiotics and other classes of antimicrobials. Early and accurate detection of MRSA and their antimicrobial susceptibility profile is therefore imperative for the selection of appropriate antimicrobial therapy. A total of 300 isolates of S. aureus collected from January 2010 to December 2012 were included in the study. S. aureus was characterized based on morphological and biochemical characters. To receive a pure culture, the isolates were grown on mannitol salt agar with supplement 5% v/v egg yolk emulsion. Antibiotic susceptibility testing was carried out on the strains by disc diffusion technique and the results interrupted according to Clinical laboratory standards International (CLSI) guidelines. A significant proportion of the S. aureus isolates were obtained from the exudates (226) specimens in all the three years followed by blood (48), urine (16) and respiratory (10). The average resistance seen in the 300 isolates tested was ampicillin (97.2%), cephelaxin (94%), cefotaxime (96.4%), cloxacillin (100%), erythromycin (82.6%), Gentamycin (76.3%), ciprofloxacin (54.4%), clindamycin (40.4%) and linezolid and vancomycin were susceptible for all the strains. In conclusion, the prevalence of MRSA in our health-care setting is 45% among the clinical isolates of S. aureus. Active screening and proper infection control procedures need to be adopted to control the MRSA infection.

Survival of &lt;i&gt;Salmonella&lt;/i&gt; Enteritidis on Four Types of Stainless Steel Surface under a Dry Condition and Recovery by Swabbing

The survival and recovery of Salmonella Enteritidis inoculated on stainless steel surfaces with different metal contents and surface finishes were examined. Two S. Enteritidis strains possessing different levels of biofilm productivity were inoculated with tryptone soya broth (TSB) and egg yolk emulsion (EY) on the surface of stainless steel squares (1 cm × 1 cm) and stored at 22℃ under a dry condition. After storage, cells were recovered from the stainless steel surfaces by swabbing with a cotton swab. The numbers of cells recovered by swabbing and the cells remaining on the stainless steel squares were counted. The survival ratio of the strain possessing high biofilm productivity was greater than that of the strain possessing low biofilm productivity. The survival ratio of S. Enteritidis suspended in TSB was often higher than that in EY. There were no significant differences in the survival and recovery ratios of S. Enteritidis based on stainless steel composition or surface finish. From all except one sample, more than 98% of viable cells of S. Enteritidis were recovered by swabbing with a cotton swab.

Purification, characterization and bactericidal activities of phospholipase A2 from the dromedary intestine

We purified a protein from the dromedary small intestine that displayed potent bactericidal activity against Gram-positive bacteria, and identified it as group-IIA phospholipase A2 (DrPLA2-IIA) by NH2-terminal sequencing and enzymatic measurements. In fact, our findings revealed that the purified PLA2-IIA was a monomeric protein with a molecular mass of about 14kDa. Pure enzyme has a specific activity of 329±25U/mg at optimal conditions (pH 9.5 and 45°C) in the presence of 6mM NaDC and 7mM CaCl2 with egg yolk emulsion as substrate and binds with a higher affinity to PE than PS and PC. Furthermore, the DrPLA2-IIA activity was dependent on Ca2+; other cations (Cd2+, Co2+, Fe2+, Mg2+, Mn2+, and Zn2+) reduced the enzymatic activity notably, suggesting that the arrangement of the catalytic site presents an exclusive structure for Ca2+. On the other hand, DrPLA2-IIA was highly bactericidal against Gram-positive bacteria with inhibition zones and IC50 values in the range of 21–27mm and 3.7–8μg/ml, respectively, whereas Gram-negative bacteria exhibited a much higher resistance. These observations suggest that the main physiological role of DrPLA2-IIA could be the defense of the intestine against bacterial infections.

Hypolipidemic Effects of Andrographolide and Neoandrographolide in Mice and Rats

Andrographolide (AND) and neoandrographolide (NEO) are the diterpenoids from the Andrographis paniculata (Acanthaceae). It is reported the diterpenoids exhibit a wide spectrum of biological activities. The aim of this study was to investigate the hypolipidemic effect of AND and NEO in hyperlipidemic mice induced by 75% yolk emulsion and in hyperlipidemic rats induced by high fat emulsion, respectively. The results showed that the levels of triglyceride, total cholesterol (TC) and low-density lipoprotein cholesterol were reduced by AND and NEO in a dose-dependent tendency in mice. Compared with the model group, the plasma TC levels of experimental groups with AND and NEO at 100 mg/kg dosage decreased by 23.9 and 20.2% in rats, respectively (P < 0.05). It was also found that the plasma aspartate transaminase and alanine transaminase levels were significantly decreased by feeding with AND and NEO in rats, compared with positive group (simvastatin) (P < 0.01). Otherwise, AND and NEO could protect the cardiovascular due to down-regulation of iNOS expression and up-regulation of eNOS expression. In conclusion, AND and NEO have potent hypolipidemic effects and protect the cardiovascular without significant liver damage.

Survival of Biofilm-Forming Salmonella on Stainless Steel Bolt Threads under Dry Conditions

We examined the survival of two biofilm-forming strains and two biofilm-deficient strains of non typhoid Salmonella (NTS) on stainless steel bolt threads under dry conditions. Five µL of tryptone soya broth or egg yolke mulsion containing NTS strains at a concentration of 9 log cfu/mL was dropped onto the thread surfaces of hexagonal bolts. After inoculation, the bolts were screwed into the nuts, and then removed (Separate type) or not removed (Unit type). The two types of samples were kept in a dry environment (20.0-25.0°C, 2-15% humidity) and bacteria on the surfaces were periodically counted. Biofilm-forming strains were recovered from all samples after 336 days of incubation, but biofilm-deficient strains were isolated from only two of 8 samples after 336 days. This finding demonstrates that NTS can survive for approximately one year on bolt threads, providing direct evidence of the potential risk of constructions having crevices or uneven surfaces as possible contamination sources. The risk of cross-contamination may be higher for biofilm-forming strains than for biofilm-deficient strains.

Expression, purification, and characterization of thermolabile hemolysin (TLH) from Vibrio alginolyticus

Hemolysin is a putative pathogenicity factor in many bacterial pathogens. In this study, a DNA fragment containing the open reading frame (1254 bp) of the thermolabile hemolysin gene (tlh) from Vibrio alginolyticus V05 was amplified and cloned into the expression plasmid pET-24d(+). The deduced amino acid sequence of the thermolabile hemolysin (TLH) shared 94 and 83% identity with the lecithin-dependent hemolysin (LDH)/TLH of V. parahaemolyticus and V. harveyi thermolabile hemolysin (VHH), respectively. The sequence analysis also indicated that it contained a GDSL lipase domain like VHH. The recombinant protein with a predicted molecular mass of 47.2 kDa was expressed in the Escherichia coli strain BL21 (DE3) as a His-tag fused protein. TLH purified by the nickel-nitrilotriacetic acid (Ni-NTA) His-Bind Resin method showed phospholipase activity on an egg yolk emulsion plate and hemolytic activity against flounder erythrocytes with a specific activity of 18 hemolytic units microg(-1). The addition of divalent cations at different concentrations decreased hemolytic activity of the purified TLH, but monavalent cations did not affect hemolytic activity. The hemolytic activity of TLH was also markedly inhibited by protein modification reagents, i.e. beta-mercaptoethanol, phenylmethylsulfonyl fluoride, and 5,5'-dithio-bis(2-nitrobenzoic acid). Moreover, TLH was toxic to zebrafish when injected intraperitoneally, with a median lethal dose (LD50) of 0.8 microg protein g(-1) fish. This work shows that TLH could potentially be developed as a vaccine and used as a diagnostic tool for vibriosis.

Differences in exoenzyme production and adherence ability of Candida spp. isolates from catheter, blood and oral cavity

Phospholipase and proteinase production and the ability of adhesion to buccal epithelial cells (BEC) of 112 Candida isolates originated from oral cavity of HIV infected patients and from blood and catheter of intensive care unit patients were investigated. The proteinase production was detected by inoculation into bovine serum albumin (BSA) agar and the phospholipase activity was performed using egg yolk emulsion. A yeast suspension of each test strain was incubated with buccal epithelial cells and the number of adherence yeast to epithelial cells was counted. A percentage of 88.1% and 55.9% of Candida albicans and 69.8% and 37.7% of non-albicans Candida isolates produced proteinase and phospholipase, respectively. Non-albicans Candida isolated from catheter were more proteolytic than C. albicans isolates. Blood isolates were more proteolytic than catheter and oral cavity isolates while oral cavity isolates produced more phospholipase than those from blood and catheter. C. albicans isolates from oral cavity and from catheter were more adherent to BEC than non-albicans Candida isolates, but the adhesion was not different among the three sources analyzed. The results indicated differences in the production of phospholipase and proteinase and in the ability of adhesion to BEC among Candida spp. isolates from different sources. This study suggests that the pathogenicity of Candida can be correlated with the infected site.

The Direct Gene Injection Using of Egg Yolk Emulsion as Carrier and its Comparison with Liposomes.

The efficiency of egg yolk emulsion in coating DNA and its delivery across cellular membranes was evaluated in comparison with liposomes DOPE . The murine leukemia viral oncogene v-abl , cloned on pBR322 was used as a DNA substrate for direct injection into mice tissue . the DNA complexes were prepared by mixing the DNA with egg yolk emulsion and liposome . Each was directly injected into mice peritoneal cavity with proper control. The gene delivery was examined phenotypically by blood analysis and cytogenetic analysis . Chromosomal changes were detected in the bone marrow as from the fourth day post inoculation through the eleventh day when chromosomal ring s could be seen . this was accompanied by decrease in the WBC count , an increase in lymphoblast cells size and percentage and the discoloration of irregular RBCs . these are typical signs of acute lymphatic leukemia . Anatomical examination have indicated 25% increase in the spleen mplemented using specific primers to confirm the integration of the delivered DNA into the genomic content of the mice tissue within 48 hr post inoculation .

Inhibition of Helicobacter pylori Growth in vitro by Saffron (Crocus sativus L.)

Objective(s) Anti-Helicobacter pylori effects of saffron (Crocus sativus L., Iridacea) and its major constituents, crocin and safranal, were evaluated. Materials and Methods Macerated aqueous and methanol extracts tested against 45 clinical isolates of Helicobacter pylori, using paper disc diffusion method (DDM) on modified egg yolk emulsion agar (EYE agar). Four antibiotics also tested against all isolates as positive control. Results Although there were small differences in sensitivity among the isolates tested, but all isolates were susceptible to methanol and aqueous extracts. The minimum inhibitory concentrations (MIC) of methanol extract, crocin and safranal measured as 677, 26.5 and 16.6 mg/ml, respectively, using agar dilution method. The results showed that high temperature did not have any effect on the activity of extracts, crocin and safranal. The effect of pH on the activity of methanol extract indicated no significant difference at pH 5 to 8, in comparison with the control. Conclusion The results indicated that saffron has a moderate anti-Helicobacter activity.

An evaluation of Clostridium perfringens media

The objective of this experiment was to compare a range of agars in terms of their suitability as cultural media for three different strains of Clostridium perfringens vegetative cells and recovery media for thermally treated C. perfringens spores. The eight media tested were; tryptose sulphite cycloserine + egg yolk emulsion (EYE) (TSC+), sulphite cycloserine − EYE (TSC−), Shahidi–Ferguson perfringens agar + EYE (SFP+), Shahidi–Ferguson perfringens agar − EYE (SFP−), oleandomycin polymyxin sulfadiazine perfringens (OPSP) (pour plate (OPSP PP) and spread plate (OPSP SP)), reinforced clostridial agar (RCA) and brain heart infusion agar (BHI). The three strains used were C. perfringens DSM 11784, C. perfringens NCTC 08237 and C. perfringens NCTC 10614. The optimum growth of the three C. perfringens vegetative cell strains was obtained on RCA and TSC, also, the addition of EYE did not improve growth. For thermally treated and untreated spores, RCA and BHI were the only media of those tested that supported the germination and growth of the spores. The results indicate that TSC− and RCA best cultured the three C. perfringens strains, while RCA was a significantly ( P ⩾ 0.05) better medium for recovering thermally treated and untreated C. perfringens spores than any other media examined in this study. This research offers definitive data with respect to recovery and growth rate of C. perfringens on a number of commercial media and could be used as a reference by researchers when choosing an appropriate medium for use in isolating and recovering C. perfringens.

Evaluation of Selective and Nonselective Media for Isolation of Helicobacter pylori from Gastric Biopsy Specimens

The aim of the present study was to compare six media, three selective and three nonselective media, to determine the best combination of media for the primary isolation of Helicobacter pylori. Over a period of 8 months, mucosal antral biopsy specimens were obtained from 97 dyspeptic patients undergoing endoscopy. Biopsy samples were plated in parallel on all six media. Egg yolk emulsion agar (EYE), Skirrow's medium and modified Thayer-Martin medium were used as selective media; modified chocolate agar (MCHOC), Triptycase Soy Agar (TSA) and brain heart infusion agar were used as nonselective media. Overall, by using these six media, H. pylori were recovered from biopsy specimens from 48 of 97 patients, yielding an isolation rate of 49%. Comparison of all possible combinations of the six media showed that the highest rate of isolation of H. pylori was 100% (48 of 48) with EYE-MCHOC, followed by 97% (47 of 48) when EYE-SK was used. Conversely, it was found that none of the media used alone yielded a 100% rate of recovery (the maximum recovery rate was 92%, which was achieved with EYE). These results indicate that the association of EYE and MCHOC yielded the maximum recovery of H. pylori from gastric biopsy specimens. Therefore, the use of selective and nonselective media in parallel offers optimal recovery rates with only a slight increase in costs.

Inactivation of Bacillus anthracis Spores by Liquid Biocides in the Presence of Food Residue

Biocide inactivation of Bacillus anthracis spores in the presence of food residues after a 10-min treatment time was investigated. Spores of nonvirulent Bacillus anthracis strains 7702, ANR-1, and 9131 were mixed with water, flour paste, whole milk, or egg yolk emulsion and dried onto stainless-steel carriers. The carriers were exposed to various concentrations of peroxyacetic acid, sodium hypochlorite (NaOCl), or hydrogen peroxide (H(2)O(2)) for 10 min at 10, 20, or 30 degrees C, after which time the survivors were quantified. The relationship between peroxyacetic acid concentration, H(2)O(2) concentration, and spore inactivation followed a sigmoid curve that was accurately described using a four-parameter logistic model. At 20 degrees C, the minimum concentrations of peroxyacetic acid, H(2)O(2), and NaOCl (as total available chlorine) predicted to inactivate 6 log(10) CFU of B. anthracis spores with no food residue present were 1.05, 23.0, and 0.78%, respectively. At 10 degrees C, sodium hypochlorite at 5% total available chlorine did not inactivate more than 4 log(10) CFU. The presence of the food residues had only a minimal effect on peroxyacetic acid and H(2)O(2) sporicidal efficacy, but the efficacy of sodium hypochlorite was markedly inhibited by whole-milk and egg yolk residues. Sodium hypochlorite at 5% total available chlorine provided no greater than a 2-log(10) CFU reduction when spores were in the presence of egg yolk residue. This research provides new information regarding the usefulness of peroxygen biocides for B. anthracis spore inactivation when food residue is present. This work also provides guidance for adjusting decontamination procedures for food-soiled and cold surfaces.

The role of Tween in inhibiting heat-induced destabilization of yolk-based emulsions

The process of heat-induced destabilization of yolk-based emulsions and the role of Tween addition in inhibiting droplet aggregation/coalescence in the thermally treated emulsions were investigated. The aim of the study was to understand the mechanism behind yolk emulsion destabilization during the application of processes such as pasteurization/sterilization and/or cooking. Data on emulsion particle size distribution were combined with results on yolk protein adsorption to clarify the role of the unadsorbed yolk protein fraction in the destabilization of the thermally treated emulsion. Surface tension measurements were also conducted to investigate yolk protein–Tween interactions at the air/water interface and their effect on emulsion stability. The presence in the emulsion continuous phase of unadsorbed yolk protein is crucial for the thermal destabilization of the system. Tween addition inhibits droplet flocculation/coalescence phenomena by shielding the reactive groups of protein molecules adsorbed at the droplet surfaces and those of unadsorbed proteins in the emulsion continuous phase which become available for interaction following heating and protein denaturation.

Comparison of Three DNA Preparation Methods for Real-Time Polymerase Chain Reaction Confirmation of Mycobacterium Avium subsp. Paratuberculosis Growth in an Automated Broth Culture System

Three methods of harvesting DNA from broth culture tubes for quantitative real-time polymerase chain reaction (qrtPCR) confirmation of Mycobacterium avium subsp. paratuberculosis (MAP) were evaluated. A commercial DNA extraction kit, the boil method (boiling for 5 minutes), or direct addition of broth culture media to the PCR reaction mix were tested. Samples were evaluated at 8 or 11 days of incubation and at the time of instrument-signal culture-positive. In total, when tested at time to instrument signal positive, 10/10 (100%) of samples extracted by the commercial method were positive on qrtPCR, whereas 9/10 (90%) were positive after the boil method, and 6/10 (60%) were positive after the direct method. Increased volumes of egg-yolk emulsion added to the culture tubes prolonged the number of cycles to threshold positive for the samples that were not subjected to commercial extraction or boiling. Samples were not reliably positive when tested at 8 or 11 days of incubation. The boil method appears to represent a reasonable time- and money-saving method to harvest DNA for qrtPCR confirmation of MAP in broth culture at time to instrument signal positive.

In vitro Anti-Helicobacter pylori Effects of Sweet Basil (Ocimum basilicum L.) and Purple Basil (Ocimum basilicum var. purpurascens)

Anti-Helicobacter pylori effects of leaves of Ocimum basilicum L. (sweet basil, Lamiaceae) and Ocimum basilicum var. purpurascens (purple basil, Lamiaceae) were evaluated. Macerated aqueous and methanol extracts were tested against 45 clinical isolates of Helicobacter pylori using paper Disc Diffusion Method (DDM) on modified egg yolk emulsion agar (EYE agar). Although there were small differences in sensitivity among the isolates tested, but all isolates were susceptible to methanol and aqueous extracts. The Minimum Inhibitory Concentrations (MIC) of the extracts from leaves of sweet basil and purple basil were 677 and 729 μg mL-1, respectively using agar dilution method. Antibacterial constituents of sweet basil extract were stable after one month of storage at 4°C but lost 31 its activity after 4 weeks at room temperature. The extract preserved its activity when heated to 80°C for 30 min and autoclaved at 121°C for 20 min. It was stable at pH 5-8. © 2006 Asian Network for Scientific Information.

Egg yolk protein gels and emulsions

Egg yolk protein gels and emulsions

Chemical and structural characterisation of low-density lipoproteins purified from hen egg yolk

Low-density lipoproteins (LDL) are considered to be the main contributors to the exceptional emulsifying activity of hen egg yolk. However, the lack of understanding of the molecular basis for LDL functionality is a significant obstacle for good control of yolk emulsions. Consequently, we have attempted to link the structure and the characteristics of LDL with their emulsifying properties. After purification of LDL, we have determined their protein and lipid compositions, their ultrastructure, and then extracted their apoproteins for physicochemical characterisation. LDL are composed of about 12% of proteins and 87% of lipids and present a spherical shape with a mean diameter of about 35 nm. LDL solubility is high, whatever the medium conditions, because of their low density. LDL contain five major apoproteins out of which the apoprotein of 15 kDa is considered to be the most surface-active. After extraction, this apoprotein showed a high proportion of amphipathic α-helix chains, explaining the high capacity of this apoprotein to adsorb at the oil–water interface.