bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maternal Immunity Provides Protection against Pertussis in Newborn Piglets
Authors: Elahi Shokrollah , Buchanan Rachelle M. , Babiuk Lorne A. , Gerdts Volker 
Published: April 2006

ABSTRACT

Pertussis continues to be a significant cause of morbidity and mortality in infants and young children worldwide. Methods to control the disease are based on vaccination with either whole-cell or acellular vaccines or treatment with antibiotics. However, despite worldwide vaccination infants are still at the highest risk for the disease. Here we used our newly developed newborn-piglet model to investigate whether transfer of maternal immunity can protect newborn piglets against infection with
Bordetella pertussis
. Pregnant sows were vaccinated with heat-inactivated
B. pertussis
or treated with saline (controls). Newborn piglets were allowed to suckle colostrum and milk for 4 to 5 days before they were challenged with 5 × 10
9
CFU of bacteria intrapulmonarily. Elevated levels of
B. pertussis
-specific secretory immunoglobulin A (S-IgA) and IgG antibodies were found in the colostrum and serum of vaccinated sows but not in those of control sows. Subsequently, significant levels of specific IgG and S-IgA were detected in the serum and bronchoalveolar lavage fluid of piglets born to vaccinated sows. Following infection with 5 × 10
9
CFU of
B. pertussis
, clinical symptoms, pathological alterations, and bacterial shedding were significantly reduced in piglets that had received passively transferred immunity. Thus, our results demonstrate that maternal immunization might represent an alternative approach to provide protection against pertussis in young infants.
Differential Expression and Transcriptional Analysis of the α-2,3-Sialyltransferase Gene in Pathogenic
Neisseria
spp
Authors: Packiam Mathanraj , Shell Dawn M. , Liu Shi V. , Liu Yao-Bin , McGee David J. , Srivastava Ranjana , Seal Samar , Rest Richard F. 
Published: April 2006

ABSTRACT

α-2,3-Sialyltransferase (Lst) is expressed on the outer membrane of
Neisseria gonorrhoeae
and
Neisseria meningitidis
and sialylates surface lipooligosaccharide (LOS), facilitating resistance to complement-mediated killing. The enzyme is constitutively expressed from a single gene (
lst
) and does not undergo antigenic or phase variation. We observed that Triton X-100 extracts of
N. gonorrhoeae
strain F62 contain about fivefold more sialyltransferase (Stase) activity than extracts of
N. meningitidis
strain MC58 ⊄3 a serogroup B acapsulate mutant. We confirmed and expanded upon this observation by showing that extracts of 16 random
N. gonorrhoeae
isolates contain various amounts of Stase activity, but, on average, 2.2-fold-more Stase activity than extracts of 16
N. meningitidis
clinical isolates, representing several serogroups and nongroupable strains. Northern and real-time reverse transcription-PCR analysis of
lst
transcript levels in
N. gonorrhoeae
and
N. meningitidis
revealed that
N. gonorrhoeae
strains express more
lst
transcript than
N. meningitidis
strains. Although transcript levels correlate with average Stase activity observed in the two species, there was not a direct correlation between
lst
transcript levels and Stase activity among individual isolates of each species. Comparison of
lst
upstream (5′
lst
) regions of
N. gonorrhoeae
and
N. meningitidis
revealed striking sequence differences characteristic of the two pathogens.
N. gonorrhoeae
5′
lst
regions possess 30-bp and 13-bp elements present as single elements or as tandem repeats that exist only as single elements in the 5′
lst
regions of
N. meningitidis
isolates. In addition, the 5′
lst
regions of
N. meningitidis
strains have 105-bp transposon-like Correia elements which are absent in
N. gonorrhoeae
. Chromosomal
N. gonorrhoeae
5′
lst
::
lacZ
translational fusions expressed 4.75 ± 0.09-fold (
n
= 4) higher β-galactosidase (β-gal) activity than
N. meningitidis
5′
lst
::
lacZ
fusions in a host-independent manner, indicating differential expression is governed at least in part by sequence variations in the 5′
lst
regions. Reporter fusion assays and promoter-mapping analysis revealed that
N. gonorrhoeae
and
N. meningitidis
use different promoters with different strengths to transcribe
lst
. In
N. gonorrhoeae
, a strong sigma 70 promoter 80 bp upstream of the translational start site is used to transcribe
lst
, whereas this promoter is inactive in
N. meningitidis
. In
N. meningitidis
, a weak sigma 70 promoter at the 3′ terminus of a 105-bp Correia repeat-enclosed element 99 bp upstream of the translational start site is used to transcribe
lst
. We conclude that differential Stase expression between
N. gonorrhoeae
and
N. meningitidis
is due at least in part to differential
lst
gene transcription.
Accessory Gene Regulator Locus of
Staphylococcus intermedius
Authors: Sung Julia M. L. , Chantler Peter D. , Lloyd David H. 
Published: April 2006

ABSTRACT

The accessory gene regulator (
agr
) locus, a candidate system for
the regulation of the production of virulence factors in
Staphylococcus intermedius
, has been
characterized. Using PCR-based genome walking, we have
obtained the first complete sequence (3,436 bp) of the accessory gene
regulator (
agr
) gene in this organism. Sequence analysis of
the
agr
gene has identified five open reading frames (ORFs),
agrB
,
agrD
,
agrC
,
agrA
, and
hld
. The translated ORF contained amino acid motifs
characteristic of the response regulator and histidine protein kinase
signal transducer of the classic two-component regulatory system.
Sequencing of the
agrD
PCR products amplified from DNA from 20
different isolates has facilitated detection of genetic variation in
the putative autoinducing peptide (AIP) within the
agr
gene of
S. intermedius
, revealing the presence of at least
three
agr
specificity groups within this species.
Classification of the
agr
gene from
S
.
intermedius
was supported by phylogenetic analysis. Real-time
PCR also revealed that the effector molecule of the
agr
system, RNAIII, was regulated in an autocrine manner in
S. intermedius
and demonstrated positive correlation
with the temporal gene expression patterns of
luk
and
entC
. Transcription of RNAIII was also dependent on self
secreted cues. Cyclic self and nonself peptides were synthesized on the
basis of the novel AIPs produced by
S. intermedius
,
which lack the cysteine necessary to form the thiolactone ring in
analogous peptides from
Staphylococcus aureus
and
Staphylococcus epidermidis
. Experiments with these
synthetic cyclic peptides indicated that self peptides led to
up-regulation of RNAIII—findings in support of the assumption
that activation of the
agr
gene is initiated by growth- and
species-specific factors generated during bacterial
growth.
In Vivo Selection for
Neisseria gonorrhoeae
Opacity Protein Expression in the Absence of Human Carcinoembryonic Antigen Cell Adhesion Molecules
Authors: Simms Amy N. , Jerse Ann E. 
Published: April 2006

ABSTRACT

The neisserial opacity (Opa) proteins are phase-variable, antigenically distinct outer membrane proteins that mediate adherence to and invasion of human cells. We previously reported that
Neisseria gonorrhoeae
Opa protein expression appeared to be selected for or induced during experimental murine genital tract infection. Here we further defined the kinetics of recovery of Opa variants from the lower genital tracts of female mice and investigated the basis for this initial observation. We found that the recovery of different Opa phenotypes from mice appears cyclical. Three phases of infection were defined. Following intravaginal inoculation with primarily Opa
−
gonococci, the majority of isolates recovered were Opa
+
(early phase). A subsequent decline in the percentage of Opa
+
isolates occurred in a majority of mice (middle phase) and was followed by a reemergence of Opa
+
variants in mice that were infected for longer than 8 days (late phase). We showed the early phase was due to selection for preexisting Opa
+
variants in the inoculum by constructing a chloramphenicol-resistant (Cm
r
) strain and following Cm
r
Opa
+
populations mixed with a higher percentage of Opa
−
variants of the wild-type (Cm
s
) strain. Reciprocal experiments (Opa
−
Cm
r
gonococci spiked with Opa
+
Cm
s
bacteria) were consistent with selection of Opa
+
variants. Based on the absence in mice of human carcinoembryonic antigen cell adhesion molecules, the major class of Opa protein adherence receptors, we conclude the observed selection for Opa
+
variants early in infection is not likely due to a specific adherence advantage and may be due to Opa-mediated evasion of innate defenses.
Role of σDin Regulating Genes and Signals duringMyxococcus xanthusDevelopment
Authors: Viswanathan Poorna , Singer Mitchell , Kroos Lee 
Published: April 2006

ABSTRACTStarvation-induced development ofMyxococcus xanthusis an excellent model for biofilm formation because it involves cell-cell signaling to coordinate formation of multicellular mounds, gene expression, and cellular differentiation into spores. The role of σD, an alternative σ factor important for viability in stationary phase and for stress responses, was investigated during development by measuring signal production, gene expression, and sporulation of asigDnull mutant alone and upon codevelopment with wild-type cells or signaling mutants. ThesigDmutant responded to starvation by inducing (p)ppGpp synthesis normally but was impaired for production of A-signal, an early cell density signal, and for production of the morphogenetic C-signal. Induction of early developmental genes was greatly reduced, and expression of those that depend on A-signal was not restored by codevelopment with wild-type cells, indicating that σDis needed for cellular responses to A-signal. Despite these early developmental defects, thesigDmutant responded to C-signal supplied by codeveloping wild-type cells by inducing a subset of late developmental genes. σDRNA polymerase is dispensable for transcription of this subset, but a distinct regulatory class, which includes genes essential for sporulation, requires σDRNA polymerase or a gene under its control, cell autonomously. The level ofsigDtranscript in arelAmutant during growth is much lower than in wild-type cells, suggesting that (p)ppGpp positively regulatessigDtranscription in growing cells. ThesigDtranscript level drops in wild-type cells after 20 min of starvation and remains low after 40 min but rises in arelAmutant after 40 min, suggesting that (p)ppGpp negatively regulatessigDtranscription early in development. We conclude that σDsynthesized during growth occupies a position near the top of a regulatory hierarchy governingM. xanthusdevelopment, analogous to σ factors that control biofilm formation of other bacteria.
Localization of automorphisms of some unbounded Levi degenerate algebraic hypersurfaces in ℂ
n
Authors: Dini G. , Primicerio A. Selvaggi 
Published: April 2006

Abstract
Let D(n, s, k) = {z∈ ℂ
n
: ( –|z
1|2 + |z
2|2)
k
+ ∑
i
s

=3 |zi
|2 – ∑
i
n

=

s

+1 |zi
|2 < 1}, where k ∈ ℤ+, 3 ≤ s ≤ n, and let M(n, s, k) = ∂D(n, s, k). We determine for any values of n, s and k the biholomorphic automorphisms of D(n, s, k), identifying, in suitable cases, the germs of biholomorphisms that map M(n, s, k) and D(n, s, k) respectively in themselves. It turns out that, if k is even and s = n, any such germ extends to a biholomorphic automorphism of D(n, s, k), while, in other cases, it is a branch of an algebraic correspondence.
Accelerated learning without semantic similarity: indirect objects
Authors: Ninio Anat 
Published: April 2006

Abstract
The hypothesis was tested that transfer and
facilitation of learning in early syntactic development does not rely on
semantic analogy among the items. The study focused on the verb-indirect object
(VI) construction. Longitudinal naturalistic speech corpora of 14
Hebrew-speaking children (1;04–2;08) were analyzed, 9 females and 5 males, White
and predominantly middle class. There was facilitation of learning among the
first 10 verbs in the VI pattern, as evidenced by the accelerating growth
curves. However, there was much semantic variability among the 10 indirect
objects, and most had no semantically similar antecedents in the same
construction. The results indicate that facilitation of learning of early syntax
is most probably not mediated by semantic similarity.
International Regulation of Biotechnology: Problems and Prospects
Authors: Blay Sam 
Published: April 2006

AbstractIntroductionOf the issues that confront modern science and the imperatives for development and human progress today, none is more controversial than biotechnology. As one author notes, within ‘a few short decades, the powerful means of biotechnology have revolutionized medicine, agriculture and environmental protection’. The potential implications of biotechnology transcend science and the environment and impact directly on the liberalisation of international trade, the protection of intellectual property rights, the right of self determination of indigenous populations and as custodians and owners of centres of biodiversity, and indeed on international relations generally. Advocates of biotechnology argue that the modification of the genetic make-up of living organisms is nothing new and that biotechnology has been part of human agricultural practices for centuries.
James Joyce and narrative territory: The distinct functions of lost time in “An Encounter” and “The Sisters”
Authors: Murphy Terence Patrick 
Published: April 2006

Abstract
In this paper, I explore the notion of lost time in critical accounts of narrative fiction. The paper begins by briefly exploring the work of the representative New Critics Brooks and Warren on the description of past time. I then move to consider the story/sequence distinction in the work of narratologists such as Genette, Chatman and Bal. As a bridge to the major discussion, I introduce Michael Toolan's Narrative (2001 [1988]) which attempts to explore how aspects of the narrative are revealed through key lexicogrammatical choices. I attempt to build on Toolan's basic insight about the importance of thematically marked sentences in a brief re-reading of the narrative discourse of Joyce's “Eveline”. In order to resolve a central difficulty in Toolan's analysis, I put forward a theory of narrative territory – the creation within the narrative discourse of a differentiated spatiotemporal continuum for the story events. Within the conceptual framework provided by the concept of the narrative territory, I then contrast the distinct functions of lost time in James Joyce's unmarked order fiction “An Encounter” and his marked order narrative “The Sisters”.
Serial form as entertainment and interpretative framework: Probability and the ‘black box’ of past experience
Authors: Betancourt Michael 
Published: April 2006

Abstract
This essay presents and discusses the ways that prior
experience constitutes a logical black box in Umberto Eco’s discussion of serial
forms in ‘Interpreting Serials’ by using the complex adaptive system model for
how complexity arises and is sustained over time, as proposed by John Holland.
In exploring how Holland’s model can account for some aspects of Eco’s past
experience, it becomes evident that a modification of both theories to
accommodate multiple, contradictory potentials simultaneously suggests we
consider meaning as a range of potentials rather than as a singular choice. Even
though the model proposed here is incomplete and tentative, it is suggestive of
possible strategies for justifying interpretations without precluding their
rejection or revision at a later time. Individual interpretations are justified
not by comparison to an external truth but by the existence of other possible
interpretations with shared characteristics that nevertheless contradict each
other.
Le statut de la pulsion dans la sémiotique narrative morphodynamique
Authors: Álvares Cristina 
Published: April 2006

Abstract
L’article examine la question des racines
pulsionnelles du narratif en analysant le statut et la fonction du concept
métapyschologique de pulsion dans les thèses sémiotiques de Jean Petitot
(Morphogenèse du sens [1985] et Physique du sens [1992]). Cette question est
d’ordre épistémologique et concerne la présence de thèses lacaniennes dans une
théorie sémiotique qui affirme la morphogenèse du sens à partir d’un
substrat naturel.
L’article explique comment les critiques que Petitot
adresse au structuralisme lacanien en 1981 s’insèrent dans une réinterprétation
bioanthropologique et naturaliste de la métapsychologie freudienne et comment
cette réinterprétation précède et prépare la refondation morphodynamique de la
sémiotique greimassienne. Après avoir discuté les arguments que Petitot présente
pour faire de Lacan un précurseur du ‘tournant morphodynamique,’ l’article se
centre sur la redéfinition de pulsion comme prégnance sémique. Il expose les
avantages théoriques de cette notion, mais aborde également l’antinomie qu’elle
contient. La conclusion en est que la redéfinition de la pulsion comme prégnance
sémique escamote la nature sexuelle de la libido et projette sur la sémiotique
morphodynamique l’ombre de ‘l’illusion archaïque.’
Crossing borders: Towards a cognitive aesthetic approach to Caravaggio and Beckett
Authors: Degan Dario Del 
Published: April 2006

Abstract
When conducting interart studies, difficulty arises
comparing art forms due to differences in discourse between genres. The problem
becomes compounded when certain art works extend their mode of communication
beyond the boundaries of their genre. Interpreting such works tends to result in
subjectivist readings that cannot be justified according to any predetermined
analytical model. Rather than negating the subjective response, this article
proposes that an artwork is realized within the mind. In examining critical
responses to Caravaggio’s painting ‘Beheading of St. John the Baptist’ and
Beckett’s play ‘Not I’ according to a cognitive aesthetic, one discovers a
rationale for considering the painting as stimulating a feeling of motion while
the play evokes a feeling of stasis, contrary to their respective
genres.
Theory and method in grammaticalization [Theorie und Methode in der Grammatikalisierung]
Authors: Lehmann Christian 
Published: April 2006

AbstractThis paper reviews a couple of theoretical and methodological issues in grammaticalization research, including in particular the relationship of grammaticalization to the synchrony/diachrony contrast, unidirectionality and degrammaticalization, lexicalization, analogy, reanalysis and lateral conversion. There are misunderstandings, both in the grammaticalization and in the anti-grammaticalization literature, of each of these issues. Grammaticalization, if construed appropriately, comprises a homogeneous set of phenomena and therefore remains a unified field of research and a worthy object of a linguistic theory.
The Whole Is More Than the Sum of Its Parts: Modeling Community‐Level Effects of UVR in Marine Ecosystems
Authors: Momo Fernando , Ferrero Emma , Eöry Matías , Esusy Marisol , Iribarren Julia , Ferreyra Gustavo , Schloss Irene , Mostajir Behzad , Demers Serge 
Published: April 2006

ABSTRACTThe effect of UVB radiation (UVBR, 290–320 nm) on the dynamics of the lower levels of the marine plankton community was modeled. The model was built using differential equations and shows a good fit to experimental data collected in mesocosms (defined as large enclosures of 1500 L filled with natural marine waters). Some unexpected results appear to be possible by indirect effects in prey (bacteria, phytoplankton and heterotrophic flagellates). In particular, apparent competition appears between small phytoplankton and bacteria. This effect is caused by a shared predator (ciliates). Another remarkable effect is an increase in bacteria and flagellates populations due to enhanced UVBR. This effect is similar to that observed under mesocosm experimental conditions and is related to the decrease of predation due to the direct damage to predators (ciliates) by UVBR. The effect of UVBR changing interaction coefficients may be dramatic on the community structure, producing big changes in equilibrium populations, as demonstrated by sensitivity analysis of the model. In order to generalize these results to field conditions it will be necessary to increase model complexity and include extra organic mater sources, mixing and sinking effects and predation by large zooplankton. This work shows that UVBR may produce community global responses that are consequence of both direct and indirect effects among populations.
What Is the Real Measure of Gas-Well Deliverability Potential?
Authors: Kabir C. S. 
Published: April 2006

Summary
This paper probes the usefulness of establishing the traditional time-variant, absolute-open-flow potential (AOFP) on a given well. Our contention is that a well's AOFP is not a measure of its future potential in a volumetric system owing to ever-declining reservoir pressure. To circumvent this reality, we suggest a two-step approach. First, conduct a multirate test to establish reservoir parameters, such as permeability, mechanical and non-Darcy skin, and average pressure. Second, with these known parameters, use an analytic tool to describe the deliverability potential for a well or a group of wells, including reservoir uncertainty and/or operational constraints.
This paper presents a simple methodology for establishing reservoir parameters and predicting a well's future deliverability potential. Field examples show that computing reservoir parameters from buildup and drawdown data and establishing the deliverability relation instills confidence in analysis. We also show that the traditional log-log graphing of the backpressure equation is no longer required because we avoid the notion of a stabilized deliverability concept.
An analytic reservoir simulator was developed to handle well location in various drainage shapes using the pressure-transient analog for rate computation. Material-balance calculations form the backbone when depletion sets in. This simulator is also capable of handling the uncertainty of various input variables and performs full-factorial design calculations for a three-level design (that is, P10, P50, and P90). This feature facilitates capturing uncertainty of drainage area and/or any other variables while predicting future rates.
Herrschaft und Gemeinschaft im Westsudan
Authors: von Werder Peter 
Published: April 2006

Opening ParagraphDie historische Wirklichkeit der Völker erlaubt uns, im Hintergrund ihres sozialen Prozesses als letztlich bestimmende Richtlinien zwei Strukturprinzipien zu erkennen. Dies sind die in den beiden Begriffen Gemeinschaft und Herrschaft festgelegten Moglichkeiten sozialer Ordnung, die als Sozialsysteme aufgefasst werden müssen. Mit ihrer Hilfe können wir zu einem vertieften Verständnis der sozialhistorischen Entwicklung und zu einer Erkenntnis der einzelnen Phasen ihres Verlaufes in einem Volk oder Stamm gelangen.
The Image of Janus in African Sculpture
Authors: von Sydow Eckart 
Published: April 2006

Opening ParagraphAmong the vast range of subjects found in African sculpture, the representations of Janus occupy an important position, primarily for purely artistic reasons. On the whole, African sculptors chiefly excel in their treatment of single figures, be they masks or statues. Each piece of work which is more than one figure is in itself a notable advance on the usual African style. Now there are Janus masks which in their formal structure are chefs-d'œvre of African sculpture and, indeed, of all primitive art. A number of these come from the Cross River district. It is not only, however, because of their artistic form and powerful expression that these masks are interesting. Again and again men have racked their brains in order to solve the problem of their inner meaning, and have risked the most daring hypotheses, as is shown in the book by R. Karutz, Das Rätsel des Janus (1927, Basle): I shall discuss this critically at the end of this article.