bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genes of the antioxidant system of the honey bee: annotation and phylogeny
Authors: Corona M. , Robinson G. E. 
Published: October 2006

AbstractAntioxidant enzymes perform a variety of vital functions including the reduction of life‐shortening oxidative damage. We used the honey bee genome sequence to identify the major components of the honey bee antioxidant system. A comparative analysis of honey bee with Drosophila melanogaster and Anopheles gambiae shows that although the basic components of the antioxidant system are conserved, there are important species differences in the number of paralogs. These include the duplication of thioredoxin reductase and the expansion of the thioredoxin family in fly; lack of expansion of the Theta, Delta and Omega GST classes in bee and no expansion of the Sigma class in dipteran species. The differential expansion of antioxidant gene families among honey bees and dipteran species might reflect the marked differences in life history and ecological niches between social and solitary species.
Oxidatively Derived Volatile Compounds in Microencapsulated Fish Oil Monitored by Solid‐phase Microextraction (SPME)
Authors: Jónsdóttir Rósa , Bragadóttir Margrét , Arnarson GudmundurÖRN 
Published: October 2006

ABSTRACT:The stability of microencapsulated fish oil was studied during storage at 4 °C for up to 20 wk. Different coating mixtures consisting of gelatin or caseinate in blends with carbohydrates (sucrose, lactose, maltodextrin) were investigated. Oxidative stability of the microencapsulated fish oil was monitored by analysis of volatile compounds using gas chromatography olfactometry (GC‐O) or GC flame ionization (GC‐FID) (SPME‐HS‐GC/O or GC/ FID and HS‐GC/MS), Oxipres test, thiobarbituric acid‐reactive substances (TBARS), and sensory analysis. Coating mixture of caseinate and lactose showed slightly better stability than the sucrose and maltodextrin caseinate mixtures. Combination of fish gelatin and maltodextrin did not show as good oxidative stability as the coating blend of caseinate, lactose, and lecithin. Hexanal, 2‐nonenal and 2,4‐decadienals were selected as quality indicators to monitor the lipid oxidation during storage of the samples. SPME‐GC‐O analysis of these indicators showed that they were representative for the oxidation occurring in the microencapsulated fish oil. SPME‐GC‐FID analysis was sensitive enough to detect oxidative changes during storage. Oxidative stability test, TBARS results, and sensory analysis were in agreement with the SPME, indicating that SPME (polydimethylsiloxane/divinylbenzene [PDMS/ DVB] fiber) can be a useful tool for rapid analysis of lipid oxidation in microencapsulated fish oil.
Fracture Analysis of Alginate Gels
Authors: Zhang Junhua , Daubert Christopher R. , Foegeding E. Allen 
Published: October 2006

ABSTRACT:The fracture properties of alginate gels were investigated using torsion and compression. The gel fracture stress correlated with Ca2+ and alginate concentration, whereas the fracture strain was insensitive to composition. Considering the relationship of fracture stress with gel network crosslink density and the energy to break covalent and noncovalent bonds, the fracture of alginate gels is hypothesized to result from the disruption of junction zones. Consequently, the fracture stress was the stress required to overcome electrostatic forces that formed junction zones. The fracture stress‐strain relationship for alginate gels can be described by the Blatz, Sharda, adn Tschoegl (BST) equation, suggesting that for a given gel, the fracture strain can be predicted based on fracture stress, small‐strain shear modulus, and a fitted parameter describing nonlinearity of the gel. In addition, the fracture properties were affected by deformation rate. The influence of deformation rate on fracture was ascribed to structural changes among the alginate junction zones.
Influence of Surface Topography on the Effectiveness of Pulsed Light Treatment for the Inactivation of Listeria innocua on Stainless‐steel Surfaces
Authors: Woodling Sarah E. , Moraru Carmen I. 
Published: October 2006

ABSTRACTPulsed light (PL) treatment has been proven effective for killing a wide variety of microorganisms on foods and food contact materials. However, there is concern regarding how shading may impact the effectiveness of PL when applied to imperfect surfaces. The main objective of this work was to examine how surface properties, particularly topography, influence the microbicidal effect of PL. Four types of stainless‐steel surfaces were inoculated with Listeria innocua and treated with up to 12 pulses of light. The highest level of inactivation achieved was about a 4‐log reduction. Initially, an increase in inactivation with increasing treatment intensity was observed, but the inactivation curves tailed off above 3 light pulses. The differences in inactivation levels among the 4 finishes at specific treatment levels were rather insignificant, but some interesting trends were observed. At low treatment levels, inactivation on the smoothest finish was slightly lower than for the other surfaces, due to clustering of the cells on the highly hydrophobic smooth surface and to its reflective nature. For the roughest surface, scanning electron microscopy (SEM) imaging confirmed the preferential location of the cells inside surface features, which also promoted a relatively uniform distribution of the cells across the surface. This counter balanced to some extent of the shading effects, and as a result inactivation on the roughest surface was comparable to inactivation on the smoother surfaces. These results demonstrate that PL can be effective on both smooth and rough surfaces, but also indicate a complex effect of various surface properties on inactivation.
Headspace Gas Chromatography‐Mass Spectrometry and Electronic Nose Analysis of Volatile Compounds in Canned Alaska Pink Salmon Having Various Grades of Watermarking
Authors: Oliveira Alexandra C.M. , Crapo Charles A. , Himelbloom Brian , Vorholt Carey , Hoffert Jennifer 
Published: October 2006

ABSTRACTVolatiles in canned pink salmon, produced from different degrees of skin watermarked raw material and stored for 2 and 9 mo, were characterized and compared using static headspace gas chromatography analysis coupled to a mass spectrometer (SHGCMS). Sulfur‐containing compounds comprised 30% to 50% of the total volatiles and tended to decrease with increasing degrees of skin watermarking, and dimethyl sulfide was the most abundant compound of this class of molecules. A few alcohols, aldehydes, ketones, and furans were also identified. Forward stepwise general discriminant analysis (FSGDA) was used to investigate prediction models based on degree of skin watermarking. The 2‐ and 9‐mo models using SHGCMS showed 92.5% and 93.75% correct classifications, respectively. The ability of the Cyranose 320, a hand‐held electronic nose (EN), to differentiate these grades of watermarking in the canned samples was also tested. EN analysis using FSGDA resulted in models with 90% and 92.5% correct classifications for the 2‐ and 9‐mo samples, respectively. Overall, results indicate that the watermarking grades studied are not readily distinguishable from each other by either method of analysis.
Influence of Flavor Variability in Skim Milk Powder on Consumer Acceptability of Ingredient Applications
Authors: Caudle Alissa D. , Yoon Youngmo , Drake MaryAnne 
Published: October 2006

ABSTRACTFlavor variability in skim milk powder (SMP) has been documented by descriptive sensory analysis and instrumental analysis. However, research has not addressed how or if SMP flavor variability impacts consumer acceptance of ingredient applications. Twenty reconstituted low‐heat SMPs were screened using a previously established defined sensory language. Two SMPs free of off‐flavors (flavor similar to fresh fluid skim milk) and 2 SMPs exhibiting off‐flavors (exhibiting flavors not found in fluid skim milk) were selected for further study. Volatile compounds were determined using solid phase microextraction (SPME) with gas chromatography‐mass spectrometry (GC‐MS). Each SMP was subsequently directly reconstituted or incorporated into standard formulas for vanilla ice cream, strawberry yogurt, hot cocoa mix, and white chocolate bars. Consumer acceptance testing was conducted. Descriptive panelists documented sweet aromatic and cooked flavors in the fresh‐flavored SMP and these flavors as well as fatty/fryer oil and animal‐like flavors in the off‐flavored SMP. Concurrently, instrumental volatile analysis revealed higher relative abundances of lipid oxidation compounds in the off‐flavored SMP. Consumer acceptance scores were lower for the off‐flavored SMP than for the fresh‐flavored SMP when evaluated directly reconstituted (P< 0.05) and for ingredient applications made using off‐flavored SMP (P< 0.05). Off‐flavors in SMP documented by descriptive analysis and trained panelists can carry through into ingredient applications with SMP and negatively affect consumer acceptability.
Formulation of Corn Zein Chewing Gum and Evaluation of Sensory Properties by the Time‐Intensity Method
Authors: McGowan Bridget A. , Padua Graciela W. , Lee Soo‐Yeun 
Published: October 2006

ABSTRACT:This study was conducted to determine the feasibility of using corn zein as a natural gum base to be an alternative to the currently used synthetic gum base. The objectives were to (1) develop a corn zein chewing gum and (2) evaluate the taste, texture, and aroma qualities compared with synthetic gum base using a time‐intensity (T‐I) method. Four corn zein gum samples, each made with a different plasticizer (oleic acid, glycerin, propylene glycol, and 1 without any plasticizer), were included in the study along with 2 synthetic gum‐base samples. Nine panelists participated in the T‐I study. Thirteen attributes were evaluated. Maximum intensity, time to maximum intensity, and duration were parameters extracted from the T‐I curve. The synthetic gum‐base samples were rated higher for the maximum intensity of sweet taste and cinnamon aroma‐by‐mouth and lower for the maximum intensity of bitter taste. The propylene glycol corn zein sample was rated the highest for cinnamon aroma and the lowest for stale, rancid, and cheesy aromas. Out of the corn zein gums, the oleic acid sample was rated the lowest for the maximum intensity of hardness. It was also rated highest for the maximum intensity of bitter taste and the lowest for sweet taste. This study showed that it is feasible to use corn zein as a gum base, but future work is needed to develop an acceptable product for consumers.
Lipid Oxidations in Ordinary and Dark Muscles of Fish: Influences on Rancid Off‐odor Development and Color Darkening of Yellowtail Flesh During Ice Storage
Authors: Sohn Jeong‐Ho , Taki Yusuke , Ushio Hideki , Kohata Tomoko , Shioya Itaru , Ohshima Toshiaki 
Published: October 2006

ABSTRACTWe investigated the role of lipid oxidation in the development of a rancid off‐odor in the early stage of ice storage in both ordinary and dark muscles of cultured yellowtail (Seriola quinqueradiata). The total lipid hydroperoxide content and thiobarbituric acid‐reactive substances (TBARS) of the dark muscle were significantly higher (P < 0.01) than those of the ordinary muscle during 2 d of ice storage. The increase in the metmyoglobin content of the dark muscle was accompanied by gradual darkening of the muscle color during ice storage. To distinguish the changes in odor characteristics of the muscles, sensory evaluation was carried out. Slight changes in the intensity of 7 different odors were noted in the ordinary muscles, and there was a significant increase in the overall, fishy, spoiled, and rancid smells of the dark muscle during 2 d of ice storage. No correlation was found between the total content of lipid hydroperoxide and the odor intensities in ordinary muscle; however, there was a significant correlation between the total lipid hydroperoxide content and rancid off‐odor and overall smell intensities in the dark muscle. The rate of lipid oxidation of the yellowtail dark muscle was significantly faster than that of the ordinary muscle. Lipid oxidation of the dark muscle was closely related to meat darkening and development of the rancid off‐odor during the early stage of ice storage.
Antioxidant Capacity of Fruit Extracts of Blackberry (Rubus sp.) Produced in Different Climatic Regions
Authors: Reyes‐Carmona Josefina , Yousef Gad G. , Martínez‐Peniche Ramon A. , Lila Mary Ann 
Published: October 2006

ABSTRACT:A range of blackberry genotypes harvested in different seasons and regions in Mexico (Michoacan) and in the United States (Pacific Northwest) were collected to determine their antioxidant capacity using oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays. Total acidity, ascorbic acid, soluble solids, total phenols, and total anthocyanins, as well as the correlation between all these parameters, were determined for all treatments. Total acidity ranged from 4.22% in wild blackberry from Patzcuaro, Mexico, to 1.02% in ‘Evergreen’ from Woodburn, Oreg. These treatments were also the outliers in terms of ascorbic acid content. Cultivar ‘Brazos’ did not exhibit any significant differences in acidity or ascorbic acid as a consequence of the geographic origin or harvest season. The highest concentration of soluble solids was recorded for ‘Evergreen’ from Woodburn and relatively low soluble solids levels were recorded for all the Mexican treatments. Wild blackberry from Patzcuaro exhibited the highest values for ORAC, FRAP, total phenolic and anthocyanin content. Other relatively high antioxidant capacity values were detected for ‘Marion’ and ‘Evergreen’, both produced in Oregon. Different cultivars grown in the same region/season consistently showed differences in antioxidant capacity. There was little effect of harvest season on phenolic levels. We conclude that levels of total acidity, ascorbic acid, soluble solids, antioxidant capacity, and polyphenols mainly depended on the genotype and not on the climate or the season. ORAC and FRAP values were both highly correlated with each other, and with total phenols and anthocyanin content.
Presence in the 'silent’terminus region of the Escherichia coli K12 chromosome of cryptic gene(s) encoding a new nitrate reductase
Authors: Bonnefoy V. , Burinl J.‐F. , Giordano G. , Pascal M.‐C. , Chippaux M. 
Published: October 2006

SummaryA cosmid complementing narG mutants defective in nitrate reductase activity was isolated from a genomic library of Escherichia coli. The restriction map of the insert differed from that of the narGHI operon. The new enzyme, termed NarZ, required molybdenum for activity. The expression of narZ was not affected by the factors controlling narGHI. Insertion mutations indicated that the narZ locus covered about 8 kb of DNA; narZ is located at 32.5 U on the chromosome, in the cotransduction gap near the replication terminus. Southern blot experiments under stringent conditions using narGHI or narZ DNA as probes revealed a large extent of homology, with a small area of very high homology. We propose that narZ and narGHI have descended from a common ancestor by gene duplication.
Localization of a conserved epitope and an azurin‐like domain in the H.8 protein of pathogenic Neisseria
Authors: Kawula T. H. , Spinota S. M. , Klapper D. G. , Cannon J. G. 
Published: October 2006

SummaryThe pathogenic neisseriae, Neisseria gonorrhoeae and Neisseria meningitidis, possess an outer membrane protein, H.8, which contains a conserved monoclonal antibody (MAb)‐binding epitope in all strains tested. We have cloned and sequenced a meningococcal H.8 gene, and determined the characteristics of the predicted protein. The predicted signal peptide has features characteristic of a prokaryotic lipoprotein. The region at the N‐terminal end of the mature protein (39 amino acids) is primarily composed of alanine, glutamate and prollne residues arranged in imperfect repeats with the consensus sequence AAEAP. The epitope for H.8 MAb‐binding was localized to a 20‐amino acid sequence within this region. The remainder of the predicted amino acid sequence shows extensive homology to azurins, which are small blue copper‐binding proteins found in a limited number of species of pathogenic bacteria.
Identification, cloning and sequence analysis of the Bacillus sphaericus 1593 41.9 kD larvicidal toxin gene
Authors: Hindley J. , Berry C. 
Published: October 2006

SummaryA number of strains of the widespread aerobic soil bacterium, Bacillus sphaericus, possess crystalline inclusions of a toxin lethal to a variety of insect (larvae) which are vectors of major tropical diseases. Partlal amino acid sequence data from one strain, B. sphaerlcus 2362 have permitted us to design oLigo‐nucleotide probes for identifying the toxin gene in the closely related B. sphaericus 1593. The gene was found to be contained within an Eco RI‐Hin dIII fragment and was cloned in its entirety in the bacterial plasmid pUC12. The DNA sequence was determined together with the upstream and downstream controlling elements, and a sequence of 370 amino acids was deduced for the toxin protein. This is the first reported sequence of a B. sphaericus toxin gene and will facilitate further work in characterizing the genes from other strains of different virulence and host range. The data do not support the suggestion that the toxin is derived by proteolysis of a protoxin precursor.
Distinct control sites located upstream from the levansucrase gene of Bacillus subtilis
Authors: Klier A. , Fouet. A. , Debarbouille. M. , Kunst F. , Rapoport G. 
Published: October 2006

SummaryThe sacR regulatory region, which modulates the expression of sacB, the structural gene for ievansucrase, was separated into two parts: an upstream region which carries a constitutive promoter and a downstream region which carries a palindromic structure. Three types of fusions were constructed in which the aphA3 gene coding for kanamycin resistance of Streptococcus faecalis was placed downstream from different deleted sacR regions. Other fusions were constructed by inserting a promoter from phage SPO1 upstream from the sacB gene and part of the sacA region. A third kind of fusion was constructed in which the palindromic structure was flanked by a heterologous promoter and a heterologous structural gene. After introduction of these fusions into the chromosomal DNA of mutants affected in sacB regulation, it was possible to reveal different targets for the regulatory genes sacU, sacQ and sacS: the sacU and sacQ genes act on a region located near or just upstream from the promoter, and the sacS gene, which is involved in the Induction process, acts on the palindromic structure.
Common mechanism controlling phase and antigenic variation in pathogenic Neisseriae
Authors: Stern A. , Meyer T. F. 
Published: October 2006

SummaryThe expression of the Neisseria gonorrhoeae opacity protein (Op, protein II), a major antigenic determinant of the outer membrane, is subject to frequent phase transitions. At least nine expression loci (opaE) are involved in the production of a large number of serologically distinct Op types. Using opa‐specific oligonucleotides as probes in genomic blots, we detect Op‐related gene sequences (opr) in N. meninglitidis as well as in N. lactamica. DNA sequence analysis of such opr genes derived from N. meninglitidis reveals distinct regions of homology with gonococcal opa E genes. As shown in the immunoblot, the proteins encoded by ops and opr are serologically related. Like the opa E genes, the 5′‐coding sequences of the opr genes include a repetitive sequence composed of pentameric CTCTT units. The number of these coding repeat (CR) units is variable. This finding, together with the observation that all opr genes are constitutively transcribed, regardless of the status of protein production, suggests a translational control mechanism identical to that of the opa genes in gonococci. The related structures and control mechanisms of opa and opr genes imply a general significance of their gene products for the pathogenic character of the investigated Neisseria species.
An 18 amino acid amphiphilic helix forms the membrane‐anchoring domain of the Escherichia coli penicillin‐binding protein 5
Authors: Jackson M. E. , Pratt J. M. 
Published: October 2006

SummarySmall (10 residue) C‐terminal deletions of PBP5 cause release of this Inner membrane protein into the periplasm, indicating disruption of the membrane binding domain. To define the extent of the membrane anchoring domain, oligonucleotide‐directed mutagenesis was used to introduce both single amino acid changes and novel restriction sites into the DN A, allowing subsequent construction of precise internal deletions. The 10 C‐terminal amino acid residues possess very weak membrane anchoring potential. By extending the sequence to 18 residues membrane binding equivalent to that of authentic PBP5 was achieved. A proline substitution in this region, breaking a potential α‐helix, also disrupts the membrane binding domain. These results are discussed with respect to the amphi‐philicity of the C‐terminal sequence when arranged in an α‐helix.
Cloning and nucleotide sequence of the thrB gene from the cyanobacterium Calothrix PCC 7601
Authors: Parsot C. , Mazel D. 
Published: October 2006

SummaryThe cyanobacterium Calothrix PCC 7601 thrB gene, encoding homoserine kinase (EC 2.7.1.39), was cloned via complementation of an Escherichia coli threonine auxotroph, and its nucleotide sequence was determined. The comparison of the homoserine kinase amino acid sequences from Calothrix PCC 7601, E. coli K12 and Bacillus subtilis 168 indicates a closer relationship between cyanobacteria and bacillaceae than between cyanobacteria and enterobacteriaceae. Sequence analysis of the 5′ and 3′ flanking regions of the Calothrix thrB gene revealed the existence of a 169‐codon‐long open reading frame downstream from thrB: this sequence may be the second gene of a Calothrix thr operon. Two types of tandemly repeated sequences, sharing similarities with other prokaryotic transcriptional regulatory elements, were detected in the region upstream from the thrB gene.
DNA sequence analysis of three missense mutations affecting colicin E3 bactericidal activity
Authors: Escuyer V. , Mock M. 
Published: October 2006

SummaryWe have determined the nucleotide sequence changes caused by three missense mutations leading to the production of inactive colicin E3 proteins. The ceaC1 mutation, affecting the transiocation of colicin E3 through bacterial membranes, is caused by a serine to phenylalanine change at position 37 within the glycine‐rich region at the N‐terminal part of colicin E3. This confirms previous results suggesting a role for this domain in colicin uptake by sensitive cells. The ceaC2 and ceaC3 mutations, abolishing colicin E3 RNase activity, affect the C‐terminal enzymatic domain of the molecule, in the ceaC2 mutant, serine at position 529 was converted to leucine. The ceaC3 mutation replaced a glycine residue at position 524 with an aspartic acid residue. The two mutations ceaC2 and ceaC3 yieid information on the amino acid residues involved in the RNase activity of colicin E3.