bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrio cholerae
Hemagglutinin/Protease Degrades Chironomid Egg Masses
Authors: Halpern Malka , Gancz Hanan , Broza Meir , Kashi Yechezkel 
Published: July 2003

ABSTRACT

Cholera is a severe diarrheal disease caused by specific serogroups of
Vibrio cholerae
that are pathogenic to humans. The disease does not persist in a chronic state in humans or animals. The pathogen is naturally present as a free-living organism in the environment. Recently, it was suggested that egg masses of the nonbiting midge
Chironomus
sp. (Diptera) harbor and serve as a nutritive source for
V. cholerae
, thereby providing a natural reservoir for the organism. Here we report that
V. cholerae
O9, O1, and O139 supernatants lysed the gelatinous matrix of the chironomid egg mass and inhibited eggs from hatching. The extracellular factor responsible for the degradation of chironomid egg masses (egg mass degrading factor) was purified from
V. cholerae
O9 and O139 and was identified as the major secreted hemagglutinin/protease (HA/P) of
V. cholerae.
The substrate in the egg mass was characterized as a glycoprotein. These findings show that HA/P plays an important role in the interaction of
V. cholerae
and chironomid egg masses.
Microplate Bioassay for Nisin in Foods, Based on Nisin-Induced Green Fluorescent Protein Fluorescence
Authors: Reunanen J. , Saris P. E. J. 
Published: July 2003

ABSTRACTA plasmid coding for the nisin two-component regulatory proteins, NisK and NisR, was constructed; in this plasmid agfpgene (encoding the green fluorescent protein) was placed under control of the nisin-induciblenisFpromoter. The plasmid was transformed into non-nisin-producingLactococcus lactisstrain MG1614. The new strain could sense extracellular nisin and transduce it to green fluorescent protein fluorescence. The amount of fluorescence was dependent on the nisin concentration, and it could be measured easily. By using this strain, an assay for quantification of nisin was developed. With this method it was possible to measure as little as 2.5 ng of pure nisin per ml in culture supernatant, 45 ng of nisin per ml in milk, 0.9 μg of nisin in cheese, and 1 μg of nisin per ml in salad dressings.
Identification of Two-Component Regulatory Systems in
Bifidobacterium infantis
by Functional Complementation and Degenerate PCR Approaches
Authors: MacConaill Laura E. , Butler Derek , O'Connell-Motherway Mary , Fitzgerald Gerald F. , van Sinderen Douwe 
Published: July 2003

ABSTRACT

Two-component signal transduction systems (2CSs) are widely used by bacteria to sense and adapt to changing environmental conditions. With two separate approaches, three different 2CSs were identified on the chromosome of the probiotic bacterium
Bifidobacterium infantis
UCC 35624. One locus was identified by means of functional complementation of an
Escherichia coli
mutant. Another two were identified by PCR with degenerate primers corresponding to conserved regions of one protein component of the 2CS. The complete coding regions for each gene cluster were obtained, which showed that each 2CS-encoding locus specified a histidine protein kinase and an assumed cognate response regulator. Transcriptional analysis of the 2CSs by Northern blotting and primer extension identified a number of putative promoter sequences for this organism while revealing that the expression of each 2CS was growth phase dependent. Analysis of the genetic elements involved revealed significant homology with several distinct regulatory families from other high-G+C-content bacteria. The conservation of the genetic organization of these three 2CSs in other bacteria, including a number of recently published
Bifidobacterium
genomes, was investigated.
Design and Application of a New Cryptic-Plasmid-Based Shuttle Vector for
Magnetospirillum magneticum
Authors: Okamura Yoshiko , Takeyama Haruko , Sekine Takumi , Sakaguchi Toshifumi , Wahyudi Aris Tri , Sato Rika , Kamiya Shinji , Matsunaga Tadashi 
Published: July 2003

ABSTRACT

A 3.7-kb cryptic plasmid designated pMGT was found in
Magnetospirillum magneticum
MGT-1. It was characterized and used for the development of an improved expression system in strain AMB-1 through the construction of a shuttle vector, pUMG. An electroporation method for magnetic bacteria that uses the cryptic plasmid was also developed.
Environmental Isolates of
Aeromonas
spp. Harboring the
cagA
-Like Gene of
Helicobacter pylori
Authors: Datta Simanti , Khan Asis , Nandy Ranjan K. , Rehman Motiur , Sinha Sutapa , Chattopadhyay Santanu , Das Suresh C. , Nair G. Balakrish 
Published: July 2003

ABSTRACT

We investigated the presence of
cagA-
like gene of
Helicobacter pylori
in environmental isolates of
Aeromonas
spp. from different water samples of Calcutta, India, by colony hybridization using a
cagA
-specific DNA probe and by PCR with
cagA
-specific primers. Nucleotide sequencing of five PCR products revealed 97 to 98% homology to canonical
cagA
of
H. pylori
26695 as well as to four clinical
H. pylori
strains from Calcutta. The
cagA
-like gene of the environmental isolates was unstable in laboratory conditions and tended to be lost upon subculturing.
Infection of
Acanthamoeba castellanii
with
Mycobacterium bovis
and
M. bovis
BCG and Survival of
M. bovis
within the Amoebae
Authors: Taylor Stephanie J. , Ahonen Leena J. , de Leij Frans A. A. M. , Dale Jeremy W. 
Published: July 2003

ABSTRACT

Survival of
Mycobacterium bovis
after ingestion by protozoa would provide an environmental reservoir for infection of cattle. We have shown that
M. bovis
survived ingestion by
Acanthamoeba castellanii
. In contrast, two strains of
M. bovis
BCG did not survive well within
Acanthamoeba.
AN INSTRUMENT TO MEASURE VELOCITY PROFILE BY MEANS OF ULTRASOUND TECHNIQUES
Authors: COLDANI G. , GHIDETTI P. , LOMBARDI R. , CORAZZA I. , ZANNOLI R. 
Published: June 2003

Using our knowledge on ultrasound-based techniques, we designed and developed the Flow Rate Profiler (FRP). This is an instrument capable of measuring the local velocities of fluids that feature bulk mechanical unhomogeneities; this property is necessary to obtain scattered acoustic signals. The FRP emits a focused ultrasound beam into the medium as a sequence of short pulses in order to estimate the velocity profile. Correlation techniques are used: they allow the required real time evaluations to be carried out without sophisticated and expensive electronic processing networks. In fact, the correlation function of stochastic processes can be obtained by analyzing only the signs of the considered samples. A real time 1-bit correlator board and the acquisition software process the echoes to obtain correlation values. After that, an off-line post-elaboration step is performed on the stored raw profiles to correct them. The system was tested in laboratory by simulating a steady state known flow in a long tube and measuring the velocity profile by the device: a strong correlation (r = 0.98) between settled values and measured ones was found. The system was then tested on normal subjects on the carotid artery. Blood flow velocity profiles, instantaneous flows, local shear rates and vessel diameters were measured.
INFLUENCE OF MECHANICAL STRESS ON EXTRACELLULAR MATRIXES SYNTHESIZED BY CHONDROCYTES SEEDED ONTO ALGINATE AND HYALURONATE-BASED 3D BIOSYSTEMS
Authors: GIGANT-HUSELSTEIN C. , DUMAS D. , HUBERT P. , BAPTISTE D. , DELLACHERIE E. , MAINARD D. , NETTER P. , PAYAN E. , STOLTZ J. F. 
Published: June 2003

Articular cartilage is an hydrated tissue that withstands and distributes mechanical stresses. The chondrocytes respond to mechanical signals by regulating their metabolic activity through complex biological and biophysical interactions with the extracellular matrix (ECM). The objective of this work was to compare, under mechanical stress, the ECMs synthesized by rat chondrocytes seeded onto biosystems based on alginate (Alg), hyaluronic acid (HA) and a HA amphiphilic derivative. The mechanical stress simulates the traumatisms resulting from accidental shocks or intensive physical exercise by knocking the biosystems together. The investigation of ECMs neosynthesized by chondrocytes was carried out according to various criteria: proliferation, proteoglycans synthesis activity, expression of type I and type II collagens and the expression of α5/β1 integrin. The results obtained for the stress applied on neosynthesized matrixes of 3, 10, 17 and 24 days evidenced a high proliferation and proteoglycans synthesis activity for cells submitted to a knocking process. For all biosystems, the neosynthesized matrix contained an important level of collagen, which was in part of type II, whatever the biosystems. Finally, the chemical modification of HA by long hydrophobic alkyl chains, affords an amphiphilic derivative with viscoelastic properties perfectly mimicking those of matricial environment of chondrocytes. This study showed that the HA amphiphilic derivative induced biological effects similar to those of parent HA containing no hydrophobic modifications.
AN ASSESSMENT OF THE ROLE OF ENVIRONMENTAL REPORTING IN SUPPORTING SHARE VALUES IN FTSE100 COMPANIES
Authors: WALMSLEY JAMES DANIEL , BOND ALAN 
Published: June 2003

This paper explores the relationship between corporate environmental reporting and share price performance amongst companies in two industry groups listed on the UK FTSE (Financial Times Stock Exchange) 100 as of the 30th July 2001. The hypothesis tested is that the production of good quality corporate environmental reports (CERs) benefits company share price, by demonstrating to investors an awareness of risk, liability, legislation and opportunities as well as providing a collection of policy, impacts, temporal trends, targets and commitment. Some other studies in this area have concluded that a positive relationship exists between corporate environmental management and performance (including environmental reporting) and share value. The results of this paper differ however, and show that on average, the production of environmental reports by FTSE100 companies (in the energy and utilities and financial services sectors) has not lead to improved historical share price performance when compared to non-reporting companies, although there is strong evidence for reduced volatility of share price. Results for sector performance varied from those obtained from individual company level. The two companies assessed as producing the best reports in their industry sector outperformed both the FTSE100 benchmark, and many of their competitors for the five-year period studied. Whilst there are many benefits to be gained by listed companies through environmental reporting, such as enhancing image and improving public and investor opinion, a positive attitude to the environment, as demonstrated through environmental reporting, can provide an indication of a truly strategic approach to business. Yet there are so many factors involved, it is not possible from the results to conclude that environmental reporting supports share value.
Intraday Variability in Quasars and BL LAC Objects
Authors: Wagner S. J. , Witzel A. 
Published: July 2003

Active galactic nuclei with flat radio spectra exhibit significant variations of continuum flux density on time scales of days or less throughout the entire wavelength range. These rapid variations tightly constrain the diameters of the emitting regions and imply extremely high photon densities if the variations are intrinsic. At radio frequencies the flux densities of compact objects may flicker due to interstellar scintillation, and in all frequency bands microlensing by stars in in­tervening galaxies may introduce variations that are not intrinsic to the source. We review the characteristics of these variations in the various electromagnetic bands. Extrinsic mechanisms may affect the light curves of compact extragalactic sources, but close correlations between flares recorded in different bands strongly support the assumption that intraday variability is an intrinsic phenomenon. The apparent brightness temperatures in the radio regime exceed 1017 K and imply relativistic beaming with very high Doppler factors, coherent radiation mechanisms, or special geometric effects.
EDWARD LAWRIE TATUM
Authors: Lederberg Joshua 
Published: July 2003

Edward L. Tatum's contributions to the founding of biochemical genetics and of bacterial genetics were instrumental in the transformation of modern biology, which increasingly has focused on the flow of information through nucleic acids and the protein structure of the cell. Tatum was most effective in collaborative investigations, in which he played the role of microbiologist and biochemist, meeting challenges of profound genetic interest. In these studies, he was instrumental in the development of microorganisms such as Neurospora and Escherichia coli as tools for fundamental genetic investigations. In 1958, he shared the Nobel Prize in Physiology and Medicine with G. W. Beadle and J. Lederberg, having been a principal partner in these separate, major lines of research.
Superantigens: Mechanism of T-Cell Stimulation and Role in Immune Responses
Authors: Herman Andrew , Kappler John W. , Marrack Philippa , Pullen Ann M. 
Published: July 2003

Superantigens combine with MHC class-II molecules to form the ligands that stimulate T cells via the Vβ element of the T-cell receptor. Two groups of superantigens have been described so far: first, endogenous murine products that include the MIs determinants, and second, bacterial products such as the Staphylococcal enterotoxins. Here, we review studies that address the interactions between the foreign superantigens and MHC class-II molecules, the mechanism of T-cell stimulation, and the role that tolerance to self -superantigens plays in shaping the T-cell repertoire. We speculate on the possible evolutionary significance of superantigens.
Lymphokine Production by Human T Cells in Disease States
Authors: Romagnani Sergio 
Published: July 2003

A large body of evidence suggests the existence of polarized human T cell responses, reminiscent of Th1 and Th2 subsets described for mouse T cells. Human Th1-like cells preferentially develop during infections by intracellular bacteria, protozoa, and viruses, whereas Th2-like cells predominate during helminthic infestations and in response to common environmental allergens. The cytokine profile of “natural immunity” evoked by different offending agents in the context of different host genetic backgrounds appears to be a critical factor in determining the phenotype of the subsequent specific response. Strongly polarized human Th1-type and Th2-type responses not only play different roles in protection, they can also promote different immunopathological reactions. Th1-type responses appear to be involved in organ specific autoimmunity, in contact dermatitis, and in some chronic inflammatory disorders of unknown etiology. In contrast, in genetically predisposed hosts, Th2-type responses against common environmental allergens are responsible for triggering of allergic atopic disorders. Altered profiles of lymphokine production may account for immune dysfunctions in some primary or acquired immunodeficiency syndromes. The role of lymphokines produced by T cells in the pathogenesis of systemic autoimmune disorders is less clear. Further work is also required to better clarify the role of T cell-derived lymphokines in protecting against tumors or in favoring their development.
GENETICS OF RIBOSOMALLY SYNTHESIZED PEPTIDE ANTIBIOTICS
Authors: Kolter Roberto , Moreno Felipe 
Published: July 2003

In recent years many peptide antibiotics have been shown to be ribosomally synthesized. Among these are many microcins, produced by diverse strains of gram-negative bacteria. While the structures and modes of action of these peptide antibiotics vary widely, many of them share several important features. Their synthesis is often induced by the cessation of growth. In addition, many of them undergo unusual posttranslational modifications to yield the mature molecule, which is often exported from the cell by a dedicated export apparatus. The genes involved in modification and export of the peptide antibiotics are generally found adjacent to the structural gene and are under the same regulation. The results supporting these conclusions are reviewed and discussed in this chapter.
Growth and Differentiation
Authors: Levi-Montalcini Rita , Angeletti Pietro U. 
Published: July 2003

The convergent trend in biological sciences already apparent in the past few years recently became more pronounced. Fields which used to be the privileged property of a restricted group are now claimed by students of different disciplines. As a consequence, in 1961, the embryo no longer belongs to the embryologist nor the microbe to the microbiologist. Barely had the fences between different biological sciences been removed when new concepts developed and old concepts appeared in a new light. Possibly no concepts profited more from this invasive trend than the old concepts of growth and differentiation. Only a few decades ago, these words conveyed mainly the idea of the developing embryo and of the laborious and intricate processes which mold it into a complete and self-supporting organism. Today, many of the biologists preoccupied with these concepts are not familiar with the embryo and, for that matter, would not be able to identify one if they were confronted with it. At present the words “growth and differentiation” have acquired such a broad significance as to encompass almost all biological sciences. Faced with the problem of delimiting the field to be discussed, the reviewers found their assignment difficult. Although one of the two would label herself an embryologist, the embryo did not benefit from her admittedly modest and one-sided knowledge of this object, not so much because of awe or the fear of not doing it justice, as because of persuasion that the embryo, as a whole, has contributed less in recent years to our understanding of growth and differentiation than simpler objects such as isolated cells or cell groups. Our presentation is divided into two parts. In the first, we review some of the work in the field of primitive organisms, isolated cells, and cell populations, and we discuss recent advances in the field of embryonic induction. In the second, the chemical aspects of growth and differentiation are presented.
Public Health Informatics: How Information-Age Technology Can Strengthen Public Health
Authors: Friede Andrew , Blum Henrik L. , McDonald Mike 
Published: July 2003

The combination of the burgeoning interest in health, health care reform and the advent of the Information Age, represents a challenge and an opportunity for public health. If public health’s effectiveness and profile are to grow, practitioners and researchers will need reliable, timely informati6n with which to make information-driven decisions, better ways to communicate, and improved tools to analyze and present new knowledge. “Public Health Informatics” (PHI) is the science of applying Information- Age technology to serve the specialized needs of public health. In this paper we define Public Health Informatics, outline specific benefits that may accrue from its widespread application, and discuss why and how an academic discipline of public health informatics should be developed. Finally, we make specific recommendations for actions that government and academia can take to assure that public health professionals have the systems, tools, and training to use PHI to advance the mission of public health.
One Foot in the Furrow: Linkages Between Agriculture, Plant Pathology, and Public Health
Authors: Scholthof Karen-Beth G. 
Published: July 2003

▪ Abstract  Plant pathology is a field of biology that focuses on understanding the nature of disease in plants as well as on more practical aspects of preventing and controlling plant diseases in crop plants that are important to agriculture. Throughout history, plant diseases have had significant effects on human health and welfare. Several examples, in both historical and contemporary contexts, are presented in this review to show how plant pathogens, biotechnology, and farming practices have affected public health. Specific topics illustrating clear linkages between agriculture and human health include allergens in the environment, food-safety and agricultural practices, mycotoxigenic fungi, agrobioterrorism, and the biological control of plant diseases. The further argument is made that in order to monitor and ensure that good health and safety practices are maintained from “farm to fork,” public health specialists may benefit from the resources and expertise of agricultural scientists.    Man does not live by bread alone—but he must have bread. And he must have      bread that is truly a staff of life, not a scepter of death ( 44 ).
Some Reflections on the Feminist Scholarship in Sociology
Authors: Komarovsky Mirra 
Published: July 2003

The emergence of the women’s movement in the 1960s presents two challenges to sociology. The more obvious task is the analysis of a social movement: How did private problems get transformed into a collective protest at that particular historical moment? This article, however, addresses itself to the contribution of a social movement to the sociology of sociology. Feminist sociologists, in representing a disadvantaged group, claim to look at society from a new angle of vision. What was the impact upon the discipline of sociology of this new perspective? Feminist criticism of mainstream sociology revealed not only vast lacunae in our knowledge but flawed interpretations of social phenomena. Feminist theoreticians have extended their criticism to some epistomelogical positions of contemporary American sociology. The purpose of this article is two-fold. It illustrates some contributions to sociology by feminist scholars (including a few precursors). Secondly, some changing trends in feminist orientations are discerned and analyzed from the perspective of the sociology of knowledge.