bluuebunny/crossref_metadata_2025 huggingface dataset:
Variations in concentrations of bacterial metabolites, enzyme activities, moisture, pH and bacterial composition between and within individuals in faeces of seven healthy adults
Authors: Ikeda N. , Saito Y. , Shimizu J. , Ochi A. , Mizutani J. , Watabe J.
Published: March 2008

Variations between and within individuals, and correlations between concentrations of bacterial metabolites, including putrefactive products, ammonia and short chain fatty acids (SCFAs), enzyme activities, moisture and pH, as well as bacterial composition, were studied in faecal samples from seven healthy adults over a period of 7 months. Large variations, both between and within individuals, were observed in concentrations of putrefactive products. Although values for ammonia, SCFAs, enzyme activities, moisture and pH were generally variable, significant person‐to‐person differences were observed.

While ranges of log viable counts of the predominant bacteria such as eubacteria, bifidobacteria and bacteroides in each subject remained between 0·2 and 1·3, those of enterobacteria, streptococci (including enterococci) and lecithinase‐negative clostridia varied between 0·4 and 3·0. Levels of bifidobacteria, enterobacteria, streptococci and total aerobic bacteria showed inter‐individual variations. Correlations were found among certain of the parameters: moisture correlated negatively with p‐cresol (r= ‐0·707), pH (r= ‐0–671) and β‐glucosidase activity (GS) (r= ‐0·608), and positively with acetic acid (r= 0·621), while negative correlations were observed in pH with acetic and butyric acids (r= ‐0·690 and ‐0·623, respectively).

No significant correlations were found between bacterial compositions, and other faecal factors such as pH, moisture, metabolic enzyme activities and concentrations of putrefactive products.
Lactoferricin, a new antimicrobial peptide
Authors: Jones E.M. , Smart A. , Bloomberg G. , Burgess L. , Millar M.R.
Published: March 2008

Lactoferricin B (LF‐B) is a peptide derived from acid‐pepsin digestion of bovine lactoferrin, which has antimicrobial properties. In order to assess the antimicrobial spectrum of LF‐B and its possible in vivo uses, the minimum inhibitory and microbicidal concentrations of pure lactoferricin B were determined for a range of bacterial species and under varying conditions of growth including growth phase and size of the inoculum, pH and ionic strength of the medium. Lactoferricin B was bactericidal against a wide range of bacteria and Candida albicans. Proteus spp., Pseudomonas cepacia and Serratia spp. were resistant. The bactericidal activity of LF‐B was inhibited by increasing ionic strength and bacterial inoculum and at acid pH. The activity of lactoferricin B was completely inhibited by the addition of 5% whole cow's milk and was reduced in the presence of increasing concentrations of mucin. These results indicate the potential of LF‐B to reduce the numbers of organisms in a simple medium, but raise doubts about its role in vivo because of its sensitivity to changes in physical variables. It may be that lactoferricin exerts a transient antimicrobial effect at mucosal surfaces.
The use of fluorogenic esters to detect viable bacteria by flow cytometry
Authors: Diaper J.P. , Edwards C.
Published: March 2008

The ability of flow cytometry (FCM) to detect viable bacteria after staining with a range of fluorogenic esters was investigated with several bacterial species. The dyes studied were the fluorescein diacetate (FDA) derivatives carboxyfluorescein diacetate, 2′,7′‐bis‐(2‐carboxyethyl)‐5(6)‐carboxyfluorescein acetoxymethyl ester and calcein acetoxymethyl ester, as well as ChemChrome B, a commercially‐available stain for the detection of viable bacteria in suspension. No one dye was found to be universal but ChemChrome B dye stained the widest number of Gram‐positive and Gram‐negative species, whereas the FDA derivatives preferentially stained Gram‐positive bacteria. The use of ChemChrome B to detect viable bacteria in environmental samples was investigated further by studying the survival of Klebsiella pneumoniae in lakewater. During survival studies, a higher number of viable bacteria were detected both by direct viable counts and FCM after staining with rhodamine 123 and ChemChrome B than by colony‐forming units, suggesting the presence of viable but nonculturable cells. These results demonstrate the potential use of FCM to enumerate viable bacteria in natural waters.
Evaluation of a rapid cultural method for identification of salmonellas in naturally contaminated veterinary samples©
Authors: Davies R.H. , Wray C.
Published: March 2008

Three thousand and forty‐two samples of post‐mortem tissues, environmental swabs, animal feed ingredients and eggs were examined by conventional methods and by a simple rapid culture method. The rapid method gave reliable presumptive identification of salmonella contamination within 48 h of the start of culture. The rapid method also showed enhanced sensitivity for detection of salmonellas, in most types of sample, particularly those taken in poultry houses and hatcheries where high levels of competitive faecal bacteria are present.
Potentially pathogenic vibrios associated with mussels from a tropical region on the Atlantic coast of Brazil
Authors: Matté Glavur R. , Matté M.H. , Sato M.I.Z. , Sanchez P.S. , Rivera I.G. , Martins M.T.
Published: March 2008

Mussels (Perna perna) harvested on the coast of Ubatuba, in three different stations in the State of São Paulo, Brazil, were examined for Vibrio spp. over a 1 year period. The ranges of most probable number (MPN 100 g‐1) were: Vibrio alginolyticus (<3–24000), V. parahaemolyticus (<3–24000), V. fluvialis (<3–1100), V. cholerae non‐O1 (<3–23), V. furnissi (< 3–30), V. mimicus (< 3–9) and V. vulnificus (< 3–3). The highest incidence was observed for V. alginolyticus (92–100%), followed by V. parahaemolyticus (67–92%), V. fluvialis (34–67%), V. vulnificus (8–17%), V. furnissii (0–17%), V. mimicus (0–17%) and V. cholerae non‐O1 (0–8%). Tests for virulence factors were positive in 34.1% of the vibrios in the rabbit ileal loop and 31.7% in the Dean test. Positive results in the Kanagawa test were obtained with 0.51% of V. parahaemolyticus strains. The mean values (MPN 100 g‐1) of faecal coliforms in mussels from the three regions varied from 1100 to 44000, and seawater collected at the same stations gave average values for faecal coliforms in the range 18–3300 MPN 100 ml‐1. These results highlight the potential risks of food poisoning associated with raw or undercooked seafood.
Aminopeptidase N from Streptococcus salivarius subsp. thermophilus NCDO 573: purification and properties
Authors: Midwinter Robyn G. , Pritchard G.G.
Published: March 2008

A 96 kDa aminopeptidase was purified from Streptococcus salivarius subsp. thermophilus NCDO 573. The enzyme had similar properties to aminopeptidases isolated from lactococci and lactobacilli and showed a high degree of N‐terminal amino acid sequence homology to aminopeptidase N from Lactococcus lactis subsp. cremoris. It catalysed the hydrolysis of a range of aminoacyl 4‐nitroanilides and 7‐amido‐4‐methylcoumarin derivatives, dipeptides, tripeptides and oligopeptides. In common with aminopeptidases from other lactic acid bacteria, the enzyme from Strep. salivarius subsp. thermophilus showed highest activity with lysyl derivatives but was also very active with arginyl and leucyl derivatives. Relative activity with alanyl, phenylalanyl, tyrosyl, seryl and valyl derivatives was considerably lower and with glycyl, glutamyl and prolyl derivatives almost negligible. The aminopeptidase also catalysed the hydrolysis of dipeptides and tripeptides but mostly at rates much less than that with L‐lysyl‐4‐nitroanilide and oligopeptides. The enzyme catalysed the successive hydrolysis of various amino acid residues from the N‐terminus of several oligopeptides but it was unable to cleave peptide bonds on the N‐terminal side of a proline residue.
Haemolytic and phospholipase C (PLC) activities of Rhodococcus equi
Authors: Smola J. , Katerov V. , Schalén C.
Published: March 2008

Rhodococcus equi, an intracellular organism causing pneumonia and lung abscesses in foals, is generally thought to be non‐haemolytic. In the present study, however, 13 of 14 representative isolates were found to be haemolytic when tested on agar media containing washed red blood cells rather than whole blood. Red cells of rabbits, dogs, horses and man were more sensitive to lysis than were those of ruminants. Two new enzymatic activities of the species were defined: a lecithinase and a phosphatidylinositol‐specific phospholipase C (PI‐PLC). As judged from tests for trypsin, temperature and ethanol sensitivity, the haemolytic activity was primarily dependent on PI‐PLC though the participation of lecithinase seemed probable. The haemolytic activity of growing strains, but not of cell‐free preparations, was partially inhibited by lecithin but enhanced by cholesterol; however, cholesterol oxidase (CO) activity, known to mediate cooperative lysis of RBC sensitized with sphingomyelin‐specific phospholipases C or D of some other species, did not contribute to the direct haemolysis caused by R. equi as demonstrated here.
Amylase production by a Gram‐positive bacterium isolated from fermenting tef (Eragrostis tef)
Authors: Lealem F. , Gashe B.A.
Published: March 2008

Bacillus sp. A‐001, which produced large amounts of amylase, was isolated from fermenting tef (Eragrostis tef) on tryptone soya agar supplemented with 1% starch. The organism grew between pH 4.5 and 10.5 with an optimum at 7–7.5. Growth occurred between 20 and 55°C but the optimum was about 35–40°C. At optimum medium pH (7.5) and a temperature of 35°C the organism entered the stationary phase after about 72 h and amylase production was at its highest (9.6 units ml‐1) at this time. Enzyme activity was optimal at pH 5.5 and 40°C and showed good thermal stability; it required 110 min to lose 50% of its activity at 70°C. The enzyme hydrolysed native starch (flour from tef, corn and kocho) to various oligosaccharides, including maltotriose, maltose and glucose.
Histamine production by wine lactic acid bacteria: isolation of a histamine‐producingstrain of Leuconostoc oenos
Authors: Lonvaud‐Funel Aline , Joyeux Annick
Published: March 2008

Populations of Leuconostoc œnos were harvested from wines containing a relatively high concentration of biogenic amines. Cultivation of the biomass in synthetic media and wine showed that it consisted of histamine‐producing strains. Histamine levels after culture depended on the quantity of precursor available and on the presence of yeast lees, which certainly enriched the medium in histidine. Ethanol and pH, which control bacterial growth rate and total population, were also significant factors: pH and low ethanol concentration enhanced histamine production.

Strain Leuc. œnos 9204 was isolated and studied since it retained its ability to produce histamine after several transfers. In synthetic medium this strain produced large amounts of histamine especially in the poorest nutritional conditions (no glucose, no L‐malic acid). These results clearly demonstrate that Leuc. œnos involvedin wine‐making might play a role in biogenic amine production. The vinification method might also influence the final amine concentration in wine.
Differential elimination of enteric bacteria by protists in a freshwater system
Authors: Iriberri J. , Azúa I. , Labirua‐Iturburu Ainhoa , Artolozaga Itxaso , Barcina Isabel
Published: March 2008

J. IRIBERRI, I. AZÚA, A. LABIRUA‐ITURBURU, I. ARTOLOZAGA AND I. BARCINA. 1994. The short‐term (1 h) and long‐term (3 d) elimination of low and high densities of five enteric bacteria, Klebsiella pneumoniae, Aeromonas hydrophila, Escherichia coli, Enterococcus faecalis and Staphylococcus epidermidis, by flagellate and ciliate protists were measured in a freshwater system. In addition, the two processes, ingestion and digestion, which cause the disappearance of those enteric bacteria as time passes, were quantified.

The results showed that the elimination of these enteric bacteria by protists depends on their initial density, which confirms that the lower the bacterial density the more difficult is their elimination. On the other hand, the short‐term and long‐term elimination rates of each enteric bacteria were different, and moreover, the order of priority for elimination in the two cases was not the same. Escherichia coli showed the highest elimination rate in short‐term experiments, while Aer. hydrophila disappeared at highest rates in long‐term experiments. This different order of priority in the elimination rates and the different digestion rates on the five enteric bacteria by phagotrophic protists indicated that the elimination in time is very much influenced by the digestive capacity on each enteric bacteria of those protists. Thus, the low digestion rates of Ent. faecalis and Staph. epidermidis by flagellates and ciliates as well as their low disappearance percentages in the long‐term experiments confirm that enteric Gram‐positive bacteria are eliminated from the aquatic systems at lower rates, because their digestion is difficult.
HM17, a new polyene antifungal antibiotic produced by a new strain of Spirillospora
Authors: Hacène H. , Kebir K. , Othmane D. Sid , Lefebvre G.
Published: March 2008

H. HACÈNE, K. KEBIR, D. SID OTHMANE AND G. LEFEBVRE. 1994. An antifungal antibiotic (HM17) was obtained from a new isolate classified to the genus Spirillospora on the basis of its chemical and morphological properties. On solid media this antibiotic strongly inhibited the growth of strians of Fusarium oxysporum formae speciales albedinis, Botrytis cinerea, Gaeumaniomyces graminis and several other fungi known to be plant and human pathogens. Antifungal activity in culture collection strains of Spirillospora has not so far been reported. The u.v. absorption spectrum and physico‐chemical characteristics place HM17 in the methylpentaene sub‐group of polyene macrolides. HM17 is different from other known methylpentaenes. This is the first report of polyene production by a Spirillospora.
An alternative microthread for the study of airborne survival of bacteria outdoors
Authors: Handley B.A. , Roe J.M.
Published: March 2008

B.A. HANDLEY AND J.M. ROE 1994. The microthread technique has frequently been used to study the survival outdoors of bacteria attached to the escape line of small spiders. Use of spiders was found to be frustrating and time‐consuming. An artificial fibre of ethylene vinyl acetate was produced easily and efficiently with a modified commercial hot glue gun. Although the resulting fibres were not as fine as spider web, no significant difference in survival of suspended bacteria was demonstrated between the two fibres either when enclosed or exposed outdoors.
Production of monoclonal antibodies against Xanthomonas campestris pv. mangiferaeindicae and their use to investigate differences in virulence
Authors: Sanders Gina M. , Verschoor J.A. , van Wyngaard S. , Korsten L. , Kotzé J.M.
Published: March 2008

G.M. SANDERS, J.A. VERSCHOOR, S. VAN WYNGAARD, L. KORSTEN AND J.M. KOTZE 1994. Four Xanthomonas campestris pv. mangiferaeindicae isolates from mango black spot lesions were grouped according to differences in virulence and used to raise monoclonal antibodies (mAbs). Two immunization approaches were followed. In the first, four groups of mice were immunized, each with a different isolate and the spleens from each group homogenized together for cell fusion. The second approach entailed immunization of a single group of mice with bacteria pooled from all four isolates. The resultant mAbs were characterized with regard to the antigen binding specificity and antibody class. A relationship between mAb binding specificity and virulence of the bacteria was shown by Western blot analysis.
Growth and metabolism of sugar and acids of Leuconostoc oenos under different conditions of temperature and pH
Authors: Pimentel Maria Serpa , Silva M.H. , Cortês Isabel , Faia Arlete Mendes
Published: March 2008

The differences in the composition of culture media inoculated with strains of Leuconostoc oenos were more quantitative than qualitative. Both temperature of incubation and pH significantly affected bacterial growth, the rates of substrate consumption and consequently the amount of metabolites produced. All strains degraded 5 g 1‐1 malate, except one at pH 3.5 and 25°C. Malate was metabolized before glucose except at higher pH (4.0 and 4.5) and temperature (32°C). Citrate was completely metabolized and its consumption rate was pH‐ and temperature‐dependent. Neither acids contributed energy for growth as the Yglu remained constant in the presence or absence of acids. There was a significant increase in fructose consumed at higher temperature. Also, the final concentration of mannitol was higher but not significantly different. The addition of acids, particularly citrate, significantly repressed mannitol formation.
Polygalacturonase production by Kluyveromyces marxianus: effect of medium composition
Authors: Schwan Rosane F. , Rose A.H.
Published: March 2008

A strain of Kluyveromyces marxianus (CCT 3172), isolated from a cocoa fermentation in Brazil, secreted an endopolygalacturonase (PG) when grown under self‐induced anaerobic conditions; neither polymethylesterase nor pectate lyase appeared in culture filtrates. Replacing glucose in the medium with sucrose had no effect on PG secretion or ethanol production. Growth in fructose‐containing medium retarded secretion of PG and ethanol, but had no effect on growth. Growth and ethanol production in media containing galactose resembled those in fructose‐containing medium, although PG secretion was lowered. Growth and PG secretion were considerably retarded in xylose‐containing medium, and were similarly affected in media containing different concentrations of glucose. Varying the concentration of ammonium sulphate in media had no effect on growth or PG secretion.
Detection of toxigenic isolates of Aspergillus flavus and related species on coconut cream agar
Authors: Dyer Sonya K. , McCammon Sharee
Published: March 2008

A new readily‐prepared medium, coconut cream agar, was developed for the detection of aflatoxin production by isolates of Aspergillus flavus and related species. Coconut cream agar, which comprised coconut cream (50%) and agar (1.5%), detected isolates of A. flavus more effectively than the synthetic media tested and was as effective as media containing desiccated coconut. Fluorescence colouring of colonies grown on coconut cream agar could be used to differentiate A. flavus from A. parasiticus and A. nomius. In addition, conidial colour of A. flavus and A. nomius was quite distinct from that of A. parasiticus.
A set of keys for biochemical identification of environmental Vibrio species
Authors: Alsina Mercedes , Blanch Anicet R.
Published: March 2008

A set of biochemical keys which provide fast and presumptive identification for Vibrio spp. is presented. They have been specially designed for environmental isolates, and can be used for strains that are Gram‐negative, give a positive oxidase test, grow on TCBS medium and are facultative anaerobes. The keys are constituted by 28 tests and a maximum of 10 tests are needed for the most complicated identification. They have been designed for routine purposes, especially for studies with a high number of isolates. Some tests are included in enzyme‐activity based kits that could be used with these keys through certain results, principally for environmental isolates, should be confirmed by standard methods.
Degradation and fermentation of α‐gluco‐oligosaccharides by bacterial strains from human colon: in vitro and in vivo studies in gnotobiotic rats
Authors: Djouzi Z. , Andrieux C. , Pelenc V. , Somarriba S. , Popot F. , Paul F. , Monsan P. , Szylit O.
Published: March 2008

The ability of several human gut bacteria to break down α‐1,2 and α‐1,6 glycosidic linkages in α‐gluco‐oligosaccharides (GOS) was investigated in vitro in substrate utilization tests. Bacteroides thetaiotaomicron, Bifidobacterium breve and Clostridium butyricum, which are usually found in the infant gut and have been associated with both beneficial and deleterious effects on health, were studied. α‐Gluco‐oligosaccharide degradation was compared in vitro and in vivo in gnotobiotic rats associated with these organisms, inoculated alone or in combination. Oligomer breakdown and short chain fatty acid and gas production indicated hydrolysis and fermentation of the substrate. In vitro and in vivo, Cl. butyricum was the least efficient in utilizing GOS, whereas Bact. thetaiotaomicron was the most efficient. Kinetic studies on GOS hydrolysis in pH‐regulated fermenters showed that α‐1,2 glucosidic bonds, which characterize the substrate, were more resistant than α‐1,6 linkages. Adaptation of gnotobiotic rats to a diet containing 2% (w/w) GOS significantly increased the hydrolysis of α 1,2 glucosidic bonds. Combination of bacteria in trixenic rats improved GOS degradation and inhibited Cl. butyricum metabolism. This inhibition was confirmed in pH‐regulated fermenters containing GOS as the principal carbon source. The association of beneficial bacteria and GOS may therefore have a potential health‐promoting effect in human necnates.
The effect of transient temperatures on the growth of Salmonella typhimurium LT2. II: excursions outside the growth region
Authors: Mitchell G.A. , Brocklehurst T.F. , Parker R. , Smith A.C.
Published: March 2008

The effect of fluctuating temperatures on microbial growth is important in the passage of foods from production to consumption. Suspensions of Salmonella typhimurium have been subjected to sinusoidally time‐varying temperatures of periods from 60 to 240 min between 4°C and 22°C, that is within and below the growth temperature range. The suspensions were prepared with two concentrations of sodium chloride and adjusted to two different values of pH. The change in the numbers of viable bacteria was measured with time and the experimental growth curves and average generation times compared with predictions based on isothermal growth data. Generally, the experimental average generation times exceeded the predictions by not more than 10% In enumerating viable bacteria in the suspensions containing 3.5% (w/v) sodium chloride it was necessary to use sodium chloride in the diluent and recovery medium in order to recover the bacteria quantitatively.
The relationship between ecophysiology, indigenous microflora and growth of Listeria monocytogenes in grass silage
Authors: Donald A.S. , Fenlon D.R. , Seddon B.
Published: March 2008

The combined effect of the physical and chemical parameters (oxygen tension, pH and dry matter) influencing Listeria monocytogenes growth and survival in silage were simultaneously studied in a model in vitro system. Ensiled grass was exposed to a range of low oxygen concentrations, 0‐5% v/v, and their effect was recorded with respect to acidification and microbial population dynamics of the epiphytic microflora, i.e. lactic acid bacteria, enterobacteria, yeasts, moulds and L. monocytogenes in grasses pre‐inoculated with the latter. Listeria monocytogenes survival depended on the establishment of a fine balance between the physico‐chemical and microbiological characteristics, i.e. oxygen tension, dry matter, pH, grass and microbiological quality. In all grasses ensiled, an oxygen concentration of 1.0% or greater sustained L. monocytogenes growth, below this level growth was shown to be principally dependent on the rate and quality of the fermentation. In most grasses 0.5% oxygen prolonged survival, whereas 0.1% and 0% oxygen caused L. monocytogenes to die off. In very poor quality grass with a restricted fermentation L. monocytogenes survival was prolonged even under anaerobic conditions.
Resistance to quaternary ammonium compounds in Staphylococcus spp. isolated from the food industry and nucleotide sequence of the resistance plasmid pST827
Authors: Heir E. , Sundheim G. , Holck A.L.
Published: March 2008

The complete nucleotide sequence of the 2.8 kb plasmid pST827 involved in resistance to the quaternary ammonium compound (QAC) benzalkonium chloride in meat‐associated staphylococci was determined. An open reading frame (ORF) similar to the QAC resistance genes qacC, ebr and smr previously reported from clinical staphylococcal strains was identified (qacC'). In addition an ORF coding for a protein (Rep827) showing extensive homology to reported replication proteins of Gram‐positive organisms was found. The occurrence of known QAC resistance genes (qacA–C) among staphylococcal strains isolated from food processing plants was studied by hybridization analysis. Of 191 isolates, 25 were resistant to benzalkonium chloride. Five of these gave no hybridization signals to probes specific for qacA–C. Further hybridization analysis indicated that pST827 or closely related plasmids are widespread among QAC‐resistant staphylococcal strains. The finding of resistant staphylococci in different areas of the food processing industry indicates that QAC resistance is a potential problem in the food processing industry.
RAPD analysis of Aeromonas salmonicida and Aeromonas hydrophila
Authors: Miyata M. , Aoki T. , Inglis V. , Yoshida T. , Endo M.
Published: March 2008

The randomly amplified polymorphic DNA (RAPD) technique was used to analyse the genetic differentiation of 13 strains of Aeromonas salmonicida subsp. salmonicida, and seven strains of Aer. hydrophila. Reproducible profiles of genomic DNA fingerprints were generated by polymerase chain reaction (PCR) using a single randomly designed primer. The RAPD profiles of all the non‐motile aeromonads, Aer. salmonicida subsp. salmonicida were identical. However, profiles of the motile aeromonads, Aer. hydrophila differed between isolates. These findings reveal genomic homogeneity in Aer. salmonicida subsp. salmonicida and genetic variety in Aer. hydrophila strains.
Surface components of shigellae involved in adhesion and haemagglutination
Authors: Haque M.A. , Qadri F. , Ohki K. , Kohashi O.
Published: March 2008

Strains of Shigella species were studied for their ability to adhere and agglutinate mammalian erythrocytes. Shigella dysenteriae and Sh. flexneri exhibited haemagglutinating (HA) properties when cultured in Casamino Acids‐Yeast Extract (CYE) broth in the presence of 1 mmol 1‐1 calcium chloride, but other shigellae did not show this property under the same culture conditions. Repeated subcultivation of Sh. boydii, Sh. sonnei and HA negative strains of Sh. dysenteriae and Sh. flexneri in CYE broth medium induced adhesive and haemagglutinating properties that were inhibited by sodium periodate. HA activities of Shigella spp. were also inhibited by N‐acetylneuraminic acid, α1‐glycoprotein and fetuin, but not by protease. Electron microscopy of Sh. dysenteriae 1, Sh. flexneri 2a, Sh. boydii 12 and Sh. sonnei 1 grown in CYE broth showed the presence of an extracellular slime layer that promoted agglutination of erythrocytes. The slime layer extracted from the cell surface of Shigella spp. showed HA properties, whereas lipopolysaccharide (LPS) obtained from the same strains, except Sh. dysenteriae 1, did not agglutinate erythrocytes. This evidence suggests that the cell surface haemagglutinin is a loosely bound slime layer which is expressed in CYE broth medium.
Development of intestinal lactobacilli in normal piglets
Authors: Naito S. , Hayashidani H. , Kaneko K. , Ogawa M. , Benno Y.
Published: March 2008

The development of intestinal Lactobacillus spp. in 18 normal piglets from six litters was investigated from 1 to 45 d after birth. Faecal Lactobacillus strains isolated from piglets and their dams were identified at species and biovar levels on the basis of carbohydrate fermentation. A definite pattern was observed in the changes of four species and 20 biovars of lactobacilli appearing in faeces, with growth of the piglets. Lactobacillus reuteri colonized the animals on the first day of birth. The Lact. acidophilus group appeared 1 week after birth and maintained high levels in the intestine. Biovars B, C and E of Lact. reuteri were recovered as major biovars on the first to fourteenth days after birth. In the third and fourth weeks after birth, however, biovars F and G of Lact. reuteri were mainly recovered from piglet faeces. By the seventh week, biovars B, C and E predominated again in the intestine. No change in the composition of species and biovars of the genus Lactobacillus in the dams was detected.
Degradation of fructans by epiphytic and inoculated lactic acid bacteria and by plant enzymes during ensilage of normal and sterile hybrid ryegrass
Authors: Merry R.J. , Winters A.L. , Thomas P.I. , Müller M. , Müller T.
Published: March 2008

Degradation of grass fructans by epiphytic or inoculated lactic acid bacteria during ensilage was examined using both normal and sterile hybrid ryegrass. It was clear that even in the absence of bacteria fructan degradation occurred, but at a significantly slower rate than in normal grass which had not been inoculated with lactic acid bacteria. Fructan degradation in sterile herbage suggests that plant fructan hydrolases were partially responsible for this process in all herbages, irrespective of treatment. Inoculation of sterile herbage with a strain of Lactobacillus plantarum known to lack the ability to degrade grass fructans resulted in a slower rate of fructan breakdown than when inoculated with Lactobacillus casei subsp. paracasei, a confirmed fructan degrader. In the later stages of the fermentation of uninoculated normal herbage when water‐soluble carbohydrate appeared to be limiting, lactic acid was fermented to acetic acid. However, this fermentation pathway was not observed in either of the inoculated silages. The results suggest that silage inoculant bacteria possessing fructan hydrolase activity may have potential for improving silage fermentation, particularly when late cut, low sugar grass containing a high proportion of fructans is ensiled.
Influence of salad constituents on growth of Pseudomonas marginalis: a predictive microbiology approach
Authors: Membré J.M. , Goubet D. , Kubaczka M.
Published: March 2008

In order to describe the behaviour of Pseudomonas marginalis on ready‐to‐use vegetables, the effects of carbon and nitrogen sources on biomass profile were evaluated. First of all, experiments were carried out in synthetic medium with a multiwell analyser, using a factorial design. To establish a predictive model, a non‐linear equation was developed: cell density profile was described by two Gompertz functions including yeast extract, pectin and fructose influences. Starch had little or no effect on growth rate of Ps. marginalis. Finally, validation of the mathematical model was performed with cultures in 50 ml synthetic medium flasks and with endive juice assays. In each case, a good agreement between model prediction and experimental data was found.
Biological activity of polyketide pigments produced by the fungus Monascus
Authors: Martínková L. , J˚zlová P. , Veselý D.
Published: March 2008

The biological activity of the pigment extracts from Monascus purpureus included their antibiotic action not only against bacteria but also against some species of yeasts and filamentous fungi, as well as embryotoxicity and teratogenicity. These activities depended on the presence of the orange component (monascorubrin and rubropunctatin). The formation of these compounds was influenced by the composition of the culture medium and by cultivation of the fungus: when amino acids, peptides or proteins were available during cultivation, as in the case of solid‐state cultivation on rice, wheat or pearl barley or submerged cultivation with an organic nitrogen source, the bioactive compounds were converted into inactive complexes and, to a lesser extent, into purple pigments (monascorubramine and rubropunctamine) which retained some biological activity. The toxicity of the orange pigments may reside in the same reaction as their detoxication, i.e. in their binding to cellular NH‐groups.
Continuous deacidification of wine by immobilized Schizosaccharomyces pombe cells: evaluation of malic acid degradation rate and analytical profiles
Authors: Ciani M.
Published: March 2008

Schizosaccharomyces pombe cells entrapped in Ca alginate gel were used under continuous fermentation conditions to evaluate the extent of malic acid degradation at different dilution rates (D, h−1) and the analytical profiles of wines obtained. Gel entrapped cells caused the deacidification of wine without affecting the analytical profiles. Maximum deacidification rate was obtained at 0.076 h−1D while higher dilution rates (up to 0.100 h−1D) resulted in a clear reduction of activity. At D‐value of 0.055 h−1, the deacidification activity remained constant during the observation period of 360 h.
Detection of Escherichia coli in potable water using direct impedance technology
Authors: Colquhoun K.O. , Timms S. , Fricker C.R.
Published: March 2008

Direct impedance measurement utilizing a medium previously described as being specific for Escherichia coli and which contains trimethylamine N‐oxide (TMAO) and glucuronic acid was used to detect E. coli in water samples. The system was compared with the Colilert® presence/absence test and the United Kingdom standard membrane nitration technique using membrane lauryl sulphate broth. The impedance method correlated well with both the traditional membrane method (93%) and the Colilert® method (93.95%) for a number of different water types. No interference from Citrobacter spp. (as reported in previous studies) was detected in this study although some Salmonella spp. did give false‐positive results. The data presented here suggest that the use of direct impedance may offer an alternative to conventional methods for the detection of E. coli in water.
Malolactic fermentation of wine: study of the influence of some physico‐chemical factors by experimental design assays
Authors: Vailiant H. , Formisyn P. , Gerbaux V.
Published: March 2008

The ability of selected lactic acid bacteria to carry out malolactic fermentation depends on the level of numerous wine characteristics. A Hadamard's experimental matrix was used to determine the main effects of 11 physico‐chemical factors on malolactic activity of three Leuconostoc œnos strains and one Lactobacillus plantarum strain. Ethanol had the greatest inhibitory effect on the achievement of malolactic fermentation for all Leuc. œnos strains. An inhibitory effect of the L‐malic acid was also found in the operating conditions. These strains show different degrees of sensitivity to pH. One of these strains was inhibited by SO2. Malolactic activity of the Lact. plantarum strain is mainly affected by a low pH, and this strain is often less efficient than Leuc. œnos strains. This methodology could be used for the selection of strains for malolactic starters. Further work is in progress using factorial design in order to determine the interactions between influential factors.
The effect of temperature on the degradation of triglycerides by a pseudomonad isolated from milk: free fatty acid accumulation as a balance between rates of triglyceride hydrolysis and fatty acid consumption
Authors: McKay D. B. , Beacham I. R.
Published: March 2008

The lipolysis of triglyceride by a lipolytic pseudomonad, LS107d2, and the net levels of free fatty acids (FFA) in milk cultures of LS107d2 have been studied as a function of temperature. The metabolism of triolein results in the accumulation of oleic acid at 4°C but, at higher temperatures, triolein is hydrolysed without detectable oleate accumulation. Temperature also has a profound effect on the levels of FFA in whole milk cultures of LS107d2, and on the temporal pattern of changes in FFA levels. The results are consistent in demonstrating that FFA consumption plays a significant role in determining the net level of FFA in milk, even in the presence of very high rates of lipolysis. Thus the net levels of FFA as a result of the growth of LS107d2 in milk are the result of a dynamic balance between rates of FFA production (by lipolysis) and subsequent consumption. Temperature can dramatically affect the levels of FFA in milk cultures, and these changes are proposed to be due to opposing influences on FFA consumption and production, affecting the balance between them.
Comparative evaluation of plasmid profiling and ribotyping in the analysis of Lactobacillus plantarum strain heterogeneity in silage
Authors: Duffner Fiona , O'Connell M.
Published: March 2008

F. DUFFNER AND M. O'CONNELL. 1995. Seventy‐two Lactobacillus plantarum isolates were recovered from six uninoculated grass silages for the purposes of firstly evaluating the usefulness of (1) restriction endonuclease digestion of total genomic DNA, (2) plasmid profiling and (3) ribotyping in Lact. plantarum strain differentiation and secondly, examining the strain heterogeneity in well preserved silage.

The three methods for differentiation were applied to 72 of the isolates and allowed at least 32 different strains to be identified. Twenty‐five different plasmid profiles were detected (26 if the absence of plasmids is included as a profile). Ribotyping with Eco RI identified only 11 patterns among the silage isolates. A variety of restriction enzymes was screened to increase the sensitivity of ribotyping to detect strain differences and Bam HI was used successfully for this purpose, differentiating all of the strains tested.

Two dominant strains (I and II) were identified in one particular silage, comprising 47% and 17% respectively of the isolates, while strains III and V comprised 37% and 25% of the Lact. plantarum population isolated from another of the silages.
Principles of separating micro‐organisms from suspensions using ultrasound
Authors: Miles C.A. , Morley M.J. , Hudson W.R. , Mackey B.M.
Published: March 2008

C.A. MILES, M.J. MORLEY, W.R. HUDSON AND B.M. MACKEY. 1995. When particles in suspension are placed in a stationary ultrasonic field, they form bands of high concentration at half‐wavelength intervals. Several theoretical papers have recently contributed to an understanding of the process but, for particles as small as bacteria, there are substantial discrepancies between the different theories, and a lack of published observations.

The threshold amplitudes required to band latex spheres (0.5‐5.0 μm diameter) were measured in the frequency range 1–3 MHz and used to establish conditions, reported here for the first time, suitable for banding and moving vegetative bacterial cells in pure culture. Ultrasonic means for separating and concentrating cream and bacteria at opposite ends of a tube containing a mixture of Escherichia coli and diluted milk are also described and the breakdown of theoretical equations at low particle size is discussed.
A novel approach to mode of action of cationic biocides morphological effect on antibacterial activity
Authors: Kanazawa A. , Ikeda T. , Endo T.
Published: March 2008

A. KANAZAWA, T. IKEDA AND T. ENDO. 1995 A new concept for the mode of action of cationic biocides is proposed in which the antibacterial activity of cationic disinfectants is ascribed essentially to molecular organizations of cations within aggregates, i.e. the activity is determined by the size of aggregates and number of active molecules comprising the aggregate. On the basis of the new concept, the morphological effect of disinfectants in aqueous solution on the antibacterial activity is discussed for low molecular weight phosphonium salts with single and double long alkyl chains (carbon number 14). The proposed new concept can be applied to all phenomena reported previously in antibacterial activity of cationic biocides and this concept is very important from the viewpoint of molecular design of more active cationic biocides.
Comparative study of the growth of Listeria monocytogenes in defined media and demonstration of growth in continuous culture
Authors: Jones C.E. , Shama G. , Andrew P.W. , Roberts I.S. , Jones Dorothy
Published: March 2008

C.E. JONES, G. SHAMA, P.W. ANDREW, I.S. ROBERTS AND D.JONES. 1995 A basic requirement for physiological studies with Listeria monocytogenes is a chemically defined medium that supports growth of the bacterium in batch and continuous culture. A number of such media have been devised but comparative studies of their efficiency are few and none has been used in continuous culture. Six of the media were compared for their ability to sustain sequential growth of L. monocytogenes in static and aerated batch culture with glucose as sole carbon source. The most suitable, judged on the basis of ease of preparation, growth rate and yield, was that of Trivett and Meyer (1971). This medium was shown to support growth of L. monocytogenes NCTC 7973 in continuous culture in a chemostat. A lytic phenomenon, noted with the same strain under anaerobic conditions and in batch culture in the chemostat, is discussed.
The effect of hydroxycinnamic acids and potassium sorbate on the growth of 11 strains of spoilage yeasts
Authors: Stead D.
Published: March 2008

D. STEAD. 1995. Hydroxycinnamic acids and their derivatives occur widely in plants, fruits and wine. The effect of the common hydroxycinnamic acids (caffeic, coumaric and ferulic acids), at concentrations of 100 and 500 mg 1‐1, on growth of 11 strains of spoilage yeasts was measured spectrophotometrically and compared with that of potassium sorbate. Ferulic acid was the most generally inhibitory hydroxycinnamic acid. At 500 mg 1‐1 it appreciably inhibited Pichia anomala, Debaryomyces hansenii and Saccharomyces cerevisiae and prevented detectable growth of one strain each of P. anomala and D. hansenii. Caffeic acid was the least inhibitory compound and coumaric acid had an intermediate effect. The more resistant strains of yeast were P. membranaefaciens, Saccharomycodes ludwigii and Zygosaccharomyces bailii. Sensitivity to hydroxycinnamic acid was, in general, associated with sensitivity to potassium sorbate; at a given concentration potassium sorbate was more inhibitory than were any of the hydroxycinnamic acids.
Production of high levels of acetoin in Saccharomyces cerevisiae wine yeasts is a recessive trait
Authors: Romano Patrizia , Suzzi Giovanna , Mortimer R. , Polsinelli M.
Published: March 2008

P. ROMANO, G. SUZZI, R. MORTIMER AND M. POLSINELLI. 1995. A genetic study of acetoin production was performed on wild wine yeast strains of Saccharomyces cerevisiae producing different amounts of the compound. By using differences found in these strains as source of genetic variability, it was found that crosses between high and low acetoin producing strains yielded the low level in the hybrids, indicating the low production as a dominant trait. Tetrad analysis showed that high vs low acetoin production is segregated as a single gene.
Influence of acidity and initial substrate temperature on germination of Rhizopus oligosporus sporangiospores during tempe manufacture
Authors: de Reu J.C. , Rombouts F.M. , Nout M.J.R.
Published: March 2008

J.C. DE REU, F.M. ROMBOUTS AND M.J.R. NOUT. 1995. During the soaking of soya beans according to an accelerated acidification method organic acids were formed, resulting in a pH decrease from 6·0 to 3·9. After 24 h of fermentation at 30°C, lactic acid was the major organic acid (2·1% w/v soak water), while acetic acid (0·3% w/v soak water) and citric acid (0·5% w/v soak water) were also found. During cooking with fresh water (ratio raw beans: water, 1: 6·5) the concentrations of lactate/lactic acid and acetate/acetic acid in the beans were reduced by 45% and 51%, respectively.

The effect of organic acids on the germination of Rhizopus olgosporus sporangiospores was studied in liquid media and on soya beans. Germination in aqueous suspensions was delayed by acetic acid: within 6 h no germination occurred at concentrations higher than 0·05% (w/v incubation medium), at pH 4·0. When soya beans were soaked in the presence of acetic acid, the inhibitory concentration depended on the pH after soaking. Lactic acid and citric acid enhanced germination in liquid medium, but not in tempe.

Inoculation of soya beans with R. oligosporus at various temperatures followed by incubation at 30°C resulted in both increased and decreased periods for the lag phase of fungal growth. A maximum difference of 3 h lag phase was found between initial bean temperatures of 25 and 37°C.

When pure cultures of homofermentative lactic acid bacteria were used in the initial soaking process, less lactic acid and acetic acid was formed during soaking than when the accelerated acidification method was used. This resulted in a reduction of the lag phase before growth of R. oligosporus by up to 4·7 h.
Screening of xylanolytic bacteria using a colour plate method
Authors: Breccia J.D. , Castro G.R. , Baigorí M.D. , Siñeriz F.
Published: March 2008

A simple procedure is described for the screening and isolation of xylanolytic bacteria, able to degrade hemicellulose. Bagasse hemicellulose was purified, cross‐linked with green dye for use as indicator, and used in a Petri dish assay for the determination of xylanolytic activity. Hydrolysis of the substrate causes the formation of transparent halos around bacterial colonies. The screening procedure was used to select thermoresistant bacteria. The four best isolates were characterized and classified as Bacillus species.
Modelling germination kinetics of spores of Clostridium tyrobutyricum: a tool for predictive microbiology
Authors: Mafart P.
Published: March 2008

Germination of spores of Clostridium tyrobutyricum between 9° and 45°C was followed by the decrease in optical density of the spore suspension. An empirical equation with three parameters is proposed to describe the time‐course of spore germination. Each parameter of the model has a direct biological significance and is modelled vs temperature. In the framework of predictive microbiology, the equation may be used for the prediction of the overall lag time of growth.
Performance and diacetyl production of commercial strains of malolactic bacteria in wine
Authors: Martineau Brigitte , Henick‐Kling T.
Published: March 2008

This study compares 11 commercial cultures of Leuconostoc oenos and Lactobacillus plantarum in Cabernet Sauvignon, Pinot Noir and Chardonnay wines. Performance of the cultures was found to be greatly influenced by wine type. Better survival of the bacteria was observed in Cabernet Sauvignon and Pinot Noir wines. The time necessary to complete malolactic fermentation (MLF) was 65 ± 14 d for Chardonnay, 71 ± 3 d for Cabernet Sauvignon, and 25 ± 8 d for Pinot Noir. The maximal rate of malate utilization was 0·4 g d‐1 for Pinot Noir, and 0·2 g d‐1 for the two other wine types. Final diacetyl concentration was lower in Chardonnay wines (highest 0·58 mg l‐1) compared to the other wines (highest 5·8 mg l‐1). Malic and citric acid were co‐metabolized by all strains. None of the strains metabolized glycerol. Significant differences in final diacetyl concentration of wine vinified with the different strains were found. Panelists could reliably differentiate MLF wines from non‐MLF wines, irrespective of their diacetyl content, indicating that diacetyl is not the only important MLF flavour.