bluuebunny/crossref_metadata_2025_split huggingface dataset:
AN EXPERIMENTAL STUDY INTO THE CAUSE OF THE INCREASED PORTAL PRESSURE IN PORTAL CIRRHOSIS
Authors: Herrick Frederick C. 
Published: June 2004

1. In the liver of portal cirrhosis there is a far freer communication between the arterial and portal currents than in the normal liver.
2. Factors contributing to the increased portal pressure in portal cirrhosis are (1) the direct communication of the arterial pressure to the portal vessels through dilated capillaries, (2) the larger volume-flow of the hepatic artery in proportion to the portal flow in cirrhosis as compared to that in the normal liver.
3. A portal cirrhotic liver gives passage to an amount of portal fluid proportionate to .its weight. There is no obstruction to the portal vessels from fibrosis in the large portal cirrhotic liver.
4. From an arterial inflow there is a free return flow through the portal as well as through the hepatic veins in both normal and cirrhotic livers.
5. From a portal inflow the return is through the hepatic vein only. The Gad's theory of valves and the arterial capillary network account for this fact.
6. The portal pressure has a decided influence on the arterial volume-flow and vice versa. This influence is more marked in the cirrhotic than in the normal liver.
7. The communication of the arterial pressure to the portal pressure is an important factor in an explanation of the increased portal pressure in portal cirrhosis.
THE EXPERIMENTAL VASCULAR LESIONS PRODUCED BY BACILLUS MALLEI
Authors: Duval Charles W. 
Published: June 2004

1. Bacillus malleiand its poison produce a variety of vascular lesions in the rabbit and the guinea pig.
2. The type of the lesion depends upon, (a) the virulence of the culture, (b) the sex of the animal and (c) the degree of acquired immunity.
3. The vascular changes of a proliferative and degenerative nature produced by the slow action of the glanders poison in rabbits and guinea pigs are analogous to the vascular lesions caused by sub-acute glanders infection in man.
4. The most common site of the glanders vascular lesions of animals and man is the peripheral vessels, and especially the smaller visceral arteries.
5. The aorta is a less common site of the experimental lesions.
6. The vascular lesions produced experimentally by Bacillus mallei and its poison consist of three processes, (a) exudation, (b) proliferation, (c) degeneration.
7. The lesions produced by sub-acute glanders in man consist of two processes, proliferation and degeneration.
8. The primary reaction of the vessels in experimental animals and in sub-acute human glanders consists of a proliferation of the endothelium of the intima.
9. The first degenerative changes observed in experimental animals and in sub-acute human glanders occur in the "innermost layer" of the media and not in the so-called " middle zone."
10. The cause of the degenerative change in the inner layer of the media appears to be interference with the nourishment of the circular muscle fibres of the media by proliferation of the endothelium of the intima.
A STUDY OF THE EFFECT OF INTRAVENOUS INJECTIONS OF SOLUTIONS OF PANCREATIC TISSUE; WITH ESPECIAL REFERENCE TO THE CAUSE OF COLLAPSE IN ACUTE PANCREATITIS
Authors: Egdahl Anfin 
Published: June 2004

From these results it is permissible to draw the following conclusions which may be used to explain certain phenomena associated especially with the onset of acute pancreatitis.
1. The sudden marked collapse of acute pancreatitis has as its most important cause a toxin or toxins derived from broken down pancreatic tissue. This toxin or toxins seem to be most powerful in the stage of degradation just after the disappearance of the biuret reaction and are probably of the nature of aromatic and amino-compounds.
2. There are various contributing factors of toxic action as peptone and trypsin, but these are to be regarded as of secondary importance.
3. Mechanical irritation as stretching of the peritoneum and irritation of the caeliac plexus is a secondary cause.
4. The glycerine produced through the action of steapsin cannot be regarded as an important cause of collapse.
ON THE CHEMISTRY AND STAINING PROPERTIES OF CERTAIN DERIVATIVES OF THE METHYLENE BLUE GROUP WHEN COMBINED WITH EOSIN
Authors: Wilson Thomas M. 
Published: June 2004

1. Eosinate of thionin gives very satisfactory staining for blood smears. It is easily prepared and dissolves readily in methylated spirits.
2. In the methods heretofore employed for making mixtures of eosin and methylene blue derivatives, the eosinates of methylene violet and methylene azure are present in very small quantities or are altogether absent.
3. Thionol and thionin are probably formed in methylene blue which has been long boiled with dilute alkalies and silver oxide.
4. Good stains of eosin and methylene blue derivatives can be obtained by a variety of manipulations.
5. Methylated spirits is more economical as a solvent for this stain and better adapted for the simple technique above described than is methyl alcohol. There is some evidence that the staining act is of a chemical nature.
G-structure on the cohomology of Hopf algebras
Authors: Farinati Marco , Solotar Andrea 
Published: June 2004

We prove that

E
x
t

A

∙

(
k
,
k
)

\mathrm {Ext} ^{\bullet }_A(k,k)

is a Gerstenhaber algebra, where

A
A

is a Hopf algebra. In case

A
=
D
(
H
)

A=D(H)

is the Drinfeld double of a finite-dimensional Hopf algebra

H
H

, our results imply the existence of a Gerstenhaber bracket on

H

G
S

∙

(
H
,
H
)

H^{\bullet }_{GS}(H,H)

. This fact was conjectured by R. Taillefer. The method consists of identifying

H

G
S

∙

(
H
,
H
)
≅

E
x
t

A

∙

(
k
,
k
)

H^{\bullet }_{GS}(H,H)\cong {\mathrm {Ext}}^{\bullet }_A(k,k)

as a Gerstenhaber subalgebra of

H

∙

(
A
,
A
)

H^{\bullet }(A,A)

(the Hochschild cohomology of

A
A

).
A practical and robust sequence search strategy for structural genomics target selection
Authors: Bray James E. , Marsden Russell L. , Rison Stuart C.G. , Savchenko Alexei , Edwards Aled M. , Thornton Janet M. , Orengo Christine A. 
Published: June 2004

Abstract
Motivation: Target selection strategies for structural genomic projects must be able to prioritize gene regions on the basis of significant sequence similarity with proteins that have already been structurally determined. With the rapid development of protein comparison software a robust prioritization scheme should be independent of the choice of algorithm and be able to incorporate different sequence similarity thresholds.
Results: A robust target selection strategy has been developed that can assign a priority level to all genes in any genome. Structural assignments to genome sequences are calculated at two thresholds and six levels (1–6) describe the prioritization of all whole genes and partial gene regions. This simple two-threshold approach can be implemented with any fold recognition or homology detection algorithms. The results for 10 genomes are presented using the SSEARCH and PSI-BLAST programs.
Availability: Programs are available on request from the authors.
Retinoic acid decreases fetal lung mesenchymal cell proliferation in vivo and in vitro
Authors: Dalvin Sussie , Komatsuzaki Katsumi , Anselmo Mark A. , Kling David E. , Schnitzer Jay J. , Kinane T. Bernard 
Published: June 2004

Retinoic acid (RA) is an important coordinator of mammalian organogenesis. RA is implicated in critical lung developmental events. Cell proliferation is precisely regulated during development. We investigated the effect of RA on proliferating mesenchymal cells in both whole organ lung cultures and cell cultures. The potential pathways required for the response were studied in cultures of lung mesenchymal cells from embryonic day (e) 12. We observed an RA‐dependent reduction in proliferation of mesenchymal cells in both whole organ and in cell culture. In mesenchymal cell cultures, RA decreased proliferation in lung mesenchymal cells by 72%. This was associated with a decrease of erk‐1/2 activity by 68%. Mesenchymal cell proliferation is erk‐1/2 dependent. Erk‐1/2 can be activated by G‐protein coupled receptors (GPCR) or tyrosine kinase receptors (RTK). RA treatment altered both the RTK and the GPCR pathways in primary lung mesenchymal cells. The Epidermal Growth Factor (EGF) dependent erk‐1/2 activation was increased by 35% whereas the Gi‐protein cascade was inhibited by 44% in cells treated with RA. Our results suggest that RA decreases proliferation of lung mesenchyme via a Gi‐protein and the erk‐1/2 signaling cascade.
Expression and function of class B scavenger receptor type I on both apical and basolateral sides of the plasma membrane of polarized testicular Sertoli cells of the rat
Authors: Nakagawa Akihisa , Nagaosa Kaz , Hirose Tomoe , Tsuda Kayoko , Hasegawa Kunio , Shiratsuchi Akiko , Nakanishi Yoshinobu 
Published: June 2004

Class B scavenger receptor type I (SR‐BI), a multiligand membrane protein, exists in various organs and cell types. In the testis, SR‐BI is expressed in two somatic cell types: Leydig cells and Sertoli cells. Unlike interstitially localized Leydig cells, Sertoli cells present within the seminiferous tubules keep contact with spermatogenic cells and form the tight junction to divide the seminiferous epithelium into the basal and adluminal compartments. In this study, the expression and function of SR‐BI in rat Sertoli cells were examined with respect to dependency on the spermatogenic cycle, the plasma membrane polarity, and the pituitary hormone follicle‐stimulating hormone (FSH). When the expression of SR‐BI was histochemically examined with testis sections, both protein and mRNA were already present in Sertoli cells during the first‐round spermatogenesis and continued to be detectable thereafter. The level of SR‐BI mRNA expression in Sertoli cells was lower at spermatogenic stages I–VI than at other stages. SR‐BI was present and functional (in mediating cellular incorporation of lipids of high density lipoprotein) at both the apical and basolateral surfaces of polarized Sertoli cells. Finally, SR‐BI expression at both the protein and mRNA levels was stimulated by FSH in cultured Sertoli cells. These results indicate that SR‐BI functions on both the apical and basolateral plasma membranes of Sertoli cells, and that SR‐BI expression in Sertoli cells changes during the spermatogenic cycle and is stimulated, at least in cultures, by FSH.
Characterization of
Mycobacterium smegmatis
Expressing the
Mycobacterium tuberculosis
Fatty Acid Synthase I (
fas1
) Gene
Authors: Zimhony Oren , Vilchèze Catherine , Jacobs William R. 
Published: June 2004

ABSTRACT

Unlike most other bacteria, mycobacteria make fatty acids with the multidomain enzyme eukaryote-like fatty acid synthase I (FASI). Previous studies have demonstrated that the tuberculosis drug pyrazinamide and 5-chloro-pyrazinamide target FASI activity. Biochemical studies have revealed that in addition to C
16:0
,
Mycobacterium tuberculosis
FASI synthesizes C
26:0
fatty acid, while the
Mycobacterium smegmatis
enzyme makes C
24:0
fatty acid. In order to express
M. tuberculosis
FASI in a rapidly growing
Mycobacterium
and to characterize the
M. tuberculosis
FASI in vivo, we constructed an
M. smegmatis
Δ
fas1
strain which contained the
M. tuberculosis fas1
homologue. The
M. smegmatis
Δ
fas1
(
attB
::
M. tuberculosis fas1
) strain grew more slowly than the parental
M. smegmatis
strain and was more susceptible to 5-chloro-pyrazinamide. Surprisingly, while the
M. smegmatis
Δ
fas1
(
attB
::
M. tuberculosis fas1
) strain produced C
26:0
, it predominantly produced C
24:0
. These results suggest that the fatty acid elongation that produces C
24:0
or C
26:0
in vivo is due to a complex interaction among FASI, FabH, and FASII and possibly other systems and is not solely due to FASI elongation, as previously suggested by in vitro studies.
A Gene from the Mesophilic BacteriumDehalococcoides ethenogenesEncodes a Novel Mannosylglycerate Synthase
Authors: Empadinhas Nuno , Albuquerque Luciana , Costa Joana , Zinder Stephen H. , Santos Manuel A. S. , Santos Helena , da Costa Milton S. 
Published: June 2004

ABSTRACTMannosylglycerate (MG) is a common compatible solute found in thermophilic and hyperthermophilic prokaryotes. In this study we characterized a mesophilic and bifunctional mannosylglycerate synthase (MGSD) encoded in the genome of the bacteriumDehalococcoides ethenogenes. mgsDencodes two domains with extensive homology to mannosyl-3-phosphoglycerate synthase (MPGS, EC 2.4.1.217) and to mannosyl-3-phosphoglycerate phosphatase (MPGP, EC 3.1.3.70), which catalyze the consecutive synthesis and dephosphorylation of mannosyl-3-phosphoglycerate to yield MG inPyrococcus horikoshii,Thermus thermophilus, andRhodothermus marinus. The bifunctional MGSD was overproduced inEscherichia coli, and we confirmed the combined MPGS and MPGP activities of the recombinant enzyme. The optimum activity of the enzyme was at 50°C. To examine the properties of each catalytic domain of MGSD, we expressed them separately inE. coli. The monofunctional MPGS was unstable, while the MPGP was stable and was characterized.Dehalococcoides ethenogenescannot be grown sufficiently to identify intracellular compatible solutes, andE. coliharboring MGSD did not accumulate MG. However,Saccharomyces cerevisiaeexpressingmgsDaccumulated MG, confirming that this gene product can synthesize this compatible solute and arguing for a role in osmotic adjustment in the natural host. We did not detect MGSD activity in cell extracts ofS. cerevisiae. Here we describe the first gene and enzyme for the synthesis of MG from a mesophilic microorganism and discuss the possible evolution of this bifunctional MGSD by lateral gene transfer from thermophilic and hyperthermophilic organisms.
Identification of σB-Dependent Genes inBacillus cereusby Proteome and In Vitro Transcription Analysis
Authors: van Schaik Willem , Zwietering Marcel H. , de Vos Willem M. , Abee Tjakko 
Published: June 2004

ABSTRACTThe alternative sigma factor σBof the food pathogenBacillus cereusis activated upon stress exposure and plays a role in the adaptive response of vegetative cells. This study describes the identification of σB-dependent genes inB. cereus. Two-dimensional gel electrophoresis was performed with protein extracts from a σB-overproducingB. cereusstrain. Nine protein spots, which were absent from the negative control, were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry or N-terminal sequencing. The σB-dependent expression of the corresponding genes was confirmed by Northern blot analysis with RNA isolated fromB. cereusATCC 14579 and itssigBnull mutant. Northern blot analysis also revealed that six other genes were part of σB-dependent operons. The proteins that are predicted to be encoded by the σB-dependent genes include an intracellular protease, a Mg2+transporter, and a thiamine biosynthesis protein (ThiG). Highly conserved promoter sites were found to precede all σB-dependent genes, with the exception ofthiG. By searching theB. cereusgenome for this conserved promoter sequence, five more candidate σB-dependent genes were identified. Northern blot analysis and in vitro transcription experiments with a reconstitutedB. cereusσB-RNA polymerase holoenzyme confirmed the σBdependency of two of these genes and strongly suggested that two other genes, encoding an oligopeptide-binding OppA-like protein and subunit II of the cytochromedubiquinol oxidase, are also σBdependent. In conclusion, σBofB. cereusnot only regulates genes directly involved in the stress response but may also control specific metabolic rearrangements.
The YopD Translocator of
Yersinia pseudotuberculosis
Is a Multifunctional Protein Comprised of Discrete Domains
Authors: Olsson Jan , Edqvist Petra J. , Bröms Jeanette E. , Forsberg Åke , Wolf-Watz Hans , Francis Matthew S. 
Published: June 2004

ABSTRACT

To establish an infection,
Yersinia pseudotuberculosis
utilizes a plasmid-encoded type III translocon to microinject several anti-host Yop effectors into the cytosol of target eukaryotic cells. YopD has been implicated in several key steps during Yop effector translocation, including maintenance of
yop
regulatory control and pore formation in the target cell membrane through which effectors traverse. These functions are mediated, in part, by an interaction with the cognate chaperone, LcrH. To gain insight into the complex molecular mechanisms of YopD function, we performed a systematic mutagenesis study to search for discrete functional domains. We highlighted amino acids beyond the first three N-terminal residues that are dispensable for YopD secretion and confirmed that an interaction between YopD and LcrH is essential for maintenance of
yop
regulatory control. In addition, discrete domains within YopD that are essential for both pore formation and translocation of Yop effectors were identified. Significantly, other domains were found to be important for effector microinjection but not for pore formation. Therefore, YopD is clearly essential for several discrete steps during efficient Yop effector translocation. Recognition of this modular YopD domain structure provides important insights into the function of YopD.
The PmrA-Regulated
pmrC
Gene Mediates Phosphoethanolamine Modification of Lipid A and Polymyxin Resistance in
Salmonella enterica
Authors: Lee Hyunwoo , Hsu Fong-Fu , Turk John , Groisman Eduardo A. 
Published: June 2004

ABSTRACT

The PmrA/PmrB regulatory system of
Salmonella enterica
controls the modification of lipid A with aminoarabinose and phosphoethanolamine. The aminoarabinose modification is required for resistance to the antibiotic polymyxin B, as mutations of the PmrA-activated
pbg
operon or
ugd
gene result in strains that lack aminoarabinose in their lipid A molecules and are more susceptible to polymyxin B. Additional PmrA-regulated genes appear to participate in polymyxin B resistance, as
pbgP
and
ugd
mutants are not as sensitive to polymyxin B as a
pmrA
mutant. Moreover, the role that the phosphoethanolamine modification of lipid A plays in the resistance to polymyxin B has remained unknown. Here we address both of these questions by establishing that the PmrA-activated
pmrC
gene encodes an inner membrane protein that is required for the incorporation of phosphoethanolamine into lipid A and for polymyxin B resistance. The PmrC protein consists of an N-terminal region with five transmembrane domains followed by a large periplasmic region harboring the putative enzymatic domain. A
pbgP pmrC
double mutant resembled a
pmrA
mutant both in its lipid A profile and in its susceptibility to polymyxin B, indicating that the PmrA-dependent modification of lipid A with aminoarabinose and phosphoethanolamine is responsible for PmrA-regulated polymyxin B resistance.
HutZ Is Required for Efficient Heme Utilization inVibrio cholerae
Authors: Wyckoff Elizabeth E. , Schmitt Michael , Wilks Angela , Payne Shelley M. 
Published: June 2004

ABSTRACTVibrio cholerae, the causative agent of cholera, requires iron for growth. One mechanism by which it acquires iron is the uptake of heme, and several heme utilization genes have been identified inV. cholerae. These include three distinct outer membrane receptors, two TonB systems, and an apparent ABC transporter to transfer heme across the inner membrane. However, little is known about the fate of the heme after it enters the cell. In this report we show that a novel heme utilization protein, HutZ, is required for optimal heme utilization.hutZ(open reading frame [ORF] VCA0907) is encoded with two other genes,hutW(ORF VCA0909) andhutX(ORF VCA0908), in an operon divergently transcribed from thetonB1operon. AhutZmutant grew poorly when heme was provided as the sole source of iron, and the poor growth was likely due to the failure to use heme efficiently as a source of iron, rather than to heme toxicity. Heme oxygenase mutants of bothCorynebacterium diphtheriaeandC. ulceransfail to use heme as an iron source. When thehutWXZgenes were expressed in the heme oxygenase mutants, growth on heme was restored, andhutZwas required for this effect. Biochemical characterization indicated that HutZ binds heme with high efficiency; however, no heme oxygenase activity was detected for this protein. HutZ may act as a heme storage protein, and it may also function as a shuttle protein that increases the efficiency of heme trafficking from the membrane to heme-containing proteins.
Sinorhizobium meliloti
Sulfotransferase That Modifies Lipopolysaccharide
Authors: Cronan Glen E. , Keating David H. 
Published: June 2004

ABSTRACT

Sinorhizobium meliloti
is a gram-negative soil bacterium found either in free-living form or as a nitrogen-fixing endosymbiont of a plant structure called the nodule. Symbiosis between
S. meliloti
and its plant host alfalfa is dependent on bacterial transcription of
nod
genes, which encode the enzymes responsible for synthesis of Nod factor.
S. meliloti
Nod factor is a lipochitooligosaccharide that undergoes a sulfate modification essential for its biological activity. Sulfate also modifies the carbohydrate substituents of the bacterial cell surface, including lipopolysaccharide (LPS) and capsular polysaccharide (K-antigen) (R. A. Cedergren, J. Lee, K. L. Ross, and R. I. Hollingsworth, Biochemistry
34:
4467-4477, 1995). We utilized the genomic sequence of
S. meliloti
to identify an open reading frame, SMc04267 (which we now propose to name
lpsS
), which encodes an LPS sulfotransferase activity. We expressed LpsS in
Escherichia coli
and demonstrated that the purified protein functions as an LPS sulfotransferase. Mutants lacking LpsS displayed an 89% reduction in LPS sulfotransferase activity in vitro. However,
lpsS
mutants retain approximately wild-type levels of sulfated LPS when assayed in vivo, indicating the presence of an additional LPS sulfotransferase activity(ies) in
S. meliloti
that can compensate for the loss of LpsS. The
lpsS
mutant did show reduced LPS sulfation, compared to that of the wild type, under conditions that promote
nod
gene expression, and it elicited a greater number of nodules than did the wild type during symbiosis with alfalfa. These results suggest that sulfation of cell surface polysaccharides and Nod factor may compete for a limiting pool of intracellular sulfate and that LpsS is required for optimal LPS sulfation under these conditions.
Dps Protects Cells against Multiple Stresses during Stationary Phase
Authors: Nair Sudha , Finkel Steven E. 
Published: June 2004

ABSTRACTDps, the nonspecific DNA-binding protein from starved cells, is the most abundant protein in stationary-phaseEscherichia coli. Dps homologs are found throughout the bacteria and in at least one archaeal species. Dps has been shown to protect cells from oxidative stress during exponential-phase growth. During stationary phase, Dps organizes the chromosome into a highly ordered, stable nucleoprotein complex called the biocrystal. We show here that Dps is required for long-term stationary-phase viability under competitive conditions and thatdpsmutants have altered lag phases compared to wild-type cells. We also show that during stationary phase Dps protects the cell not only from oxidative stress but also from UV and gamma irradiation, iron and copper toxicity, thermal stress, and acid and base shock. The protective roles of Dps are most likely achieved through a combination of functions associated with the protein-DNA binding and chromosome compaction, metal chelation, ferroxidase activity, and regulation of gene expression.