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Lactose hydrolysing ability of sonicated cultures of Lactobacillus delbrueckii ssp. bulgaricus 11842
No full textInternational audienceThe lactose-hydrolysing ability of Lactobacillus delbrueckii ssp. bulgaricus strain 11842 (LB 11842) was tested after cultivation in MRS broth under varying conditions. After sonication for an optimum time determined to be 4 min to disrupt the cells, cultures were added to various substrates, including pH 7 buffered 2.5 and 5% lactose test solution, skim milk, or a 30% lactose or whey permeate solutions. Freezing point changes were used to measure the progress of hydrolysis at a wide range of temperatures. Cultures added to the lactose test solutions resulted in 20% and 63% of the lactose being hydrolysed after 3 h at 7 and 51 °C, respectively. Values for hydrolysis in skim milk were slightly higher. Enzyme activity was not hindered in 30% lactose or 30% whey permeate solution and the hydrolysis rate was acceptable at a low temperature (7 °C) in skim milk.Aptitude à l'hydrolyse du lactosérum de cultures soniquées de Lactobacillus delbrueckii ssp. bulgaricus 11842. La capacité d'hydrolyse du lactosérum par Lactobacillus delbrueckii ssp. bulgaricus souche 11842 (LB 11842) fut testé après culture sur bouillon MRS sous différents paramètres. Après rupture des cellules par sonication pour une durée optimale de 4 min, les cultures furent incorporées à divers substrats tels la solution de référence à 2,5 ou 5 % de lactose tamponée à pH 7, le lait écrémé ou une solution de lactose ou de perméat de lactosérum contenant 30 % de lactose. La variation du point de congélation fut utilisée pour suivre l'évolution de l'hydrolyse pour une game étendue de températures. Les cultures ajoutées à la solution référence de lactose produisirent après 3 h des hydrolyses respectives de 20 % à 7 °C et 63 % à 51 °C. Des valeurs légèrement supérieures ont été obtenues pour le lait écrémé. L'activité enzymatique n'est pas entravée pour les solutions à 30 % de lactose ou 30 % de perméat de lactosérum et le taux d'hydrolyse pour le lait écrémé est acceptable à basse température (7 °C)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Extraction and characterisation of β-galactosidase produced by Bifidobacterium animalis spp. lactis Bb12 and Lactobacillus delbrueckii spp. bulgaricus ATCC 11842 grown in whey
No full textThis study investigated the production of Β-Galactosidase (Β-gal) by Bifidobacterium animalis ssp. lactis Bb12 and Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 in whey and the effect of four different extraction methods i.e. sonication, acetone-toluene, SDS-chloroform and lysozyme-EDTA treatment on enzyme activity from these organisms. Both organisms were grown in deproteinised whey containing yeast extract (3.0 g/L), peptone (5.0 g/L) and glucose (10.0 g/L) for 18 h, at 37°C for B. animalis ssp. lactis Bb12 and at 45°C for L. delbrueckii ssp. bulgaricus ATCC 11842. The optimum intracelluar β-gal activity on 15 mM o-nitrophenyl Β-D-galactopyranoside (ONPG) assay was at pH 6.8 for both organisms irrespective of the method of extraction used. Also, the effect of temperature on enzyme activity was studied at various temperatures (30, 35, 40, 45, and 50°C). At35°C and 40°C, B. animalis ssp. lactis Bb12 exhibited more intracellular β-gal activity extracted by sonication than other temperatures and methods. However, L. delbrueckii ssp. bulgaricus ATCC 11842 showed more intracellular β-gal activity at 35°C and 45°C when extracted by lysozyme-EDTA treatment. Among the four methods used for β-gal extraction, sonication gave the best result (6.80 Unit/mL) for B. animalis ssp. lactis Bb12 while lysozyme-EDTA treatment was found to be the best (7.77 Unit/mL) for L. delbrueckii ssp. bulgaricus ATCC 11842
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Conversion of isoflavone glycoside to aglycones in soy protein isolate (SPI) using crude enzyme extracted from Bifidobacterium animalis Bb12 and Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842
No full textCrude enzyme extracts from
B. animalis
Bb12 and
L. delbrueckii
ssp.
bulgaricus
ATCC 11842
were used at 0.1, 0.5, and 1.0 g/L to hydrolyse glycitin (isoflavone glycosides) to its biologically active form
(isoflavone aglycones; IA) in soymilk (SM) prepared from soy protein isolate (SPI) supplemented with 2.0%
(w/v) of D-glucose. Enumeration of microbial populations, measurement of pH and quantification of isoflavones
was carried out at 0 h, 6 h and 12 h of fermentation. The quantification of isoflavone compounds in SM was
carried out using HPLC. The biotransformation of glycitin was higher at the enzyme level of 1.0 g/L from
B.
animalis
Bb12 at 12 h than that at 0.5 g/L or 0.1 g/L, and the level of biotransformation was 74.4%, while
75.23% of glycitin was biotransformed with the enzyme extracted from
L. delbrueckii
ssp.
bulgaricus
ATCC
11842 at the same level of enzyme. The decrease in pH by
B. animalis
Bb12 was lowest with 1.0 g/L and highest
with the control (4.69). Similarly, the decrease in pH by
L. delbrueckii
ssp.
bulgaricus
ATCC 11842 was lowest
with 1.0 g/L (5.19) and highest with the control (5.86). The final viable population of the
B. animalis
Bb12
ranged from 5.94 to 7.49 log CFU/mL and that of
L. delbrueckii
ssp.
bulgaricus
ATCC 11842 ranged from 4.42
to 6.70 log CFU/mL and the organisms showed the highest viable population of 6.70 log CFU/mL at 12 h with
1.0 g/L crude enzyme
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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