bluuebunny/crossref_metadata_2025 huggingface dataset:
Reform, Growth, and Inequality in China*
Authors: KNIGHT John
Published: May 2008

This paper provides a survey of the literature on inequality in China – level, change, causes, and consequences. It attempts to answer six main questions. How much has inequality risen? What is its relation to poverty alleviation? What has happened to wealth inequality? What are the main dimensions of rising income inequality? The dimensions examined are: the rural–urban divide; urban labor market reform; regional divergence; rural–urban migration; and entrepreneurship, rent‐seeking, and corruption. Was it inevitable that inequality should rise so much? Does it matter that inequality has risen? Income distribution in China is bound up with both economic reform and economic growth. This paper concludes by considering the countervailing forces that will determine the path of inequality in future years.
Bullous Eruption in a Patient Infected With the Human Immunodeficiency Virus
Authors: De Dipankar , Kanwar Amrinder J. , Radotra Bishan D. , Narang Tarun
Published: May 2008

A 30‐year‐old man diagnosed with human immunodeficiency virus (HIV) infection 10 years earlier, presented with large tense blisters associated with minimal itching of 10 days' duration. He had no history of oral or genital erosions or ulcerations and showed no symptoms of HIV‐related illnesses. Highly active antiretroviral therapy (HAART) had been started 6 weeks earlier when his CD4 count was 116/mL. He initially received nevirapine 200 mg once daily; after 2 weeks with no skin eruptions or other adverse reactions, the dose was increased to 200 mg twice daily. Other components of his HAART included lamivudine and stavudine. The patient was not taking any other prescription or alternative medicines. During the past year, he experienced 4 episodes of intensely itchy urticarial lesions that subsided with antihistamines. The present episode of bullous lesions was also preceded by urticarial lesions. On examination, he had multiple, large, tense bullae over relatively normal‐looking skin involving all parts of the body (Figure 1). There were a few well‐defined erosions. Nikolsky and bullae spread signs were negative, and no oral or genital erosions or ulcerations were noted. Results of a complete blood count, renal and liver function tests, and chest x‐ray were within normal limits. Skin biopsy from one of the blisters showed a subepidermal bulla filled with eosinophils and polymorphonuclear leukocytes (Figure 2). The underlying dermis showed perivascular inflammatory infiltrate composed of polymorphonuclear and lymphomononuclear cells. The overall features were suggestive of bullous pemphigoid. A direct immunofluorescence test could not be done because of possible risk of cross‐infection to the operator of the cryostat. Workup for herpes simplex virus and cytomegalovirus infection also could not be performed. HAART was discontinued temporarily with the suspicion that it was the causative factor. The patient was started on oral prednisolone 40 mg/d and topical clobetasol propionate (0.05%). Within 1 week of treatment, he had significant improvement with almost complete disappearance of the lesions. A few small, tense vesicles continued to appear between. Once the lesions completely disappeared, the prednisolone was gradually tapered off and all the components of HAART were resumed. The patient did well without any recurrence of lesions, thus virtually excluding HAART as the cause of the bullous pemphigoid‐like eruptions. Subsequently, he did not return for follow‐up.

Tense, clear fluid‐filled vesicles over normal‐looking skin with well‐defined erosions.

image

Subepidermal bullae containing polymorphs and eosinophils. Dermis shows perivascular inflammatory infiltrates containing eosinophils and neutrophils. Hematoxylineosin stain, original magnification ×100.

image
Genital Human Papilloma Virus Infection: Advances in Prevention for the Long‐Term Good of All
Authors: Waugh Michael
Published: May 2008

The wonderful thing about being a physician, even an ordinary dogsbody of one, is that we live in a world in which almost every week scientists, researchers, and clinicians taking part in well‐conducted trials usually backed by private capital and the pharmaceutical industry manage to perfect advances that will ultimately benefit not just our patients but the families and society in which our patients live. That is, of course, if we bother, even in the usual way of busy practitioners, skimming through medical journals or glancing at progress from Web sources. Most of us do not do so as well as we would like, but merely by reading this article, education somehow touches us. (Damn, there goes an interruption; we have just been jolted out of our thoughts!)
Impact of Provider Self‐Management Education, Patient Self‐Efficacy, and Health Status on Patient Adherence in Heart Failure in a Veterans Administration Population
Authors: Subramanian Usha , Hopp Faith , Mitchinson Allison , Lowery Julie
Published: May 2008

To address the need for more information on predictors of adherence to heart failure (HF) self‐management regimens, this study analyzed surveys completed by 259 HF patients receiving care at 2 Veterans Affairs hospitals in 2003. Linear multivariable regression models were used to examine general health status, HF‐specific health status (Kansas City Cardiomyopathy Questionnaire) self‐management education, and self‐efficacy as predictors of self‐reported adherence to salt intake and exercise regimens. Self‐management education was provided most often for salt restriction (87%) followed by exercise (78%). In multivariable regression analyses, education about salt restriction (P=.01), weight reduction (P=.0004), self‐efficacy (P=.03), and health status (P=.003) were significantly associated with patient‐reported adherence to salt restriction. In a similar model, self‐efficacy (P=.006) and health status (P≤.0001), but not exercise education, were significantly associated with patient‐reported exercise adherence. Findings suggest that provider interventions may lead to improved adherence with HF self‐management and thus improvements in patients' health.
Flank Correction for Spiral Bevel and Hypoid Gears on a Six-Axis CNC Hypoid Generator
Authors: Shih Yi-Pei , Fong Zhang-Hua
Published: May 2008

Because the contact patterns of spiral bevel and hypoid gears are highly sensitive to tooth flank geometry, it is desirable to reduce the flank deviations caused by machine errors and heat treatment deformation. Several methods already proposed for flank correction are based on the cutter parameters, machine settings, and kinematical flank motion parameters of a cradle-type universal generator, which are modulated according to the measured flank topographic deviations. However, because of the recently developed six-axis Cartesian-type computer numerical control (CNC) hypoid generator, both face-milling and face-hobbing cutting methods can be implemented on the same machine using a corresponding cutter head and NC code. Nevertheless, the machine settings and flank corrections of most commercial Cartesian-type machines are still translated from the virtual cradle-type universal hypoid generator. In contrast, this paper proposes a flank-correction methodology derived directly from the six-axis Cartesian-type CNC hypoid generator in which high-order correction is easily achieved through direct control of the CNC axis motion. The validity of this flank-correction method is demonstrated using a numerical example of Oerlikon Spirac face-hobbing hypoid gears made by the proposed Cartesian-type CNC machine.
A Virtual Cam Method for Locating Instant Centers of Kinematically Indeterminate Linkages
Authors: Chang Yin-Ping , Her Innchyn
Published: May 2008

Kinematically indeterminate linkages are those whose complete set of instant centers cannot be obtained by Kennedy’s theorem. A linkage of this kind is often characterized as having no four-bar loop, or even if one exists, it does not lead to the finding of all other instant centers in the multiple-loop chain. This paper presents a simple graphical method for dealing with many of these linkages. While not altering the total degrees of freedom of the linkage, a virtual cam is introduced to help locate some key instant centers. This method also lends itself to applications along with Pennock’s method to achieve greater usability.
High-Performance Linear Cable Transmission
Authors: Savall Joan , Martín Javier , Avello Alejo
Published: May 2008

Cable transmissions offer several advantages such as high stiffness to weight ratio, high strength, low friction, and absence of backlash, which makes them appropriate for demanding mechanical applications. However, while extensively used as rotational transmissions, there are only a few examples of linear cable transmissions in the literature. The reason is that the up-to-date designs are based on a cable layout that leads to cable length changes during movement. This, in turn, produces negative effects such as transmission nonlinearity and cable fatigue. In this paper, an alternative design for linear cable transmissions is presented. The new design overcomes the aforementioned problems through a proper cable layout. Different applications of the new transmission are reported, validating the proposed design.
In Vitro Susceptibilities of Invasive Isolates of
Candida
Species: Rapid Increase in Rates of Fluconazole Susceptible-Dose Dependent
Candida glabrata
Isolates
Authors: Ruan Sheng-Yuan , Chu Chen-Chen , Hsueh Po-Ren
Published: May 2008

Voriconazole, posaconazole, caspofungin, micafungin, and anidulafungin demonstrated potent in vitro activities against 286 invasive
Candida
isolates. Analysis of the fluconazole susceptibilities of 204 bloodstream
Candida glabrata
isolates revealed a rapid shift from susceptible (64% in 1999 to 2001 to 19% in 2007) to susceptible-dose dependent (27% in 1999 to 2001 and 75% in 2007).
Posaconazole Enhances the Activity of Amphotericin B against Hyphae of Zygomycetes In Vitro
Authors: Perkhofer Susanne , Locher Maria , Cuenca-Estrella Manuel , Rüchel Reinhard , Würzner Reinhard , Dierich Manfred P. , Lass-Flörl Cornelia
Published: May 2008

The in vitro activity of posaconazole plus amphotericin B against conidia and hyphae of 30 clinical zygomycetes was investigated. The combination of posaconazole with amphotericin B was found to be significantly more synergistic (40%) against hyphae (
P
< 0.05) than against conidia (10%). Antagonism was not observed.
Typing of SHV Extended-Spectrum β-Lactamases by Pyrosequencing in
Klebsiella pneumoniae
Strains with Chromosomal SHV β-Lactamase
Authors: Haanperä Marjo , Forssten Sofia D. , Huovinen Pentti , Jalava Jari
Published: May 2008

In
Klebsiella pneumoniae
, the cooccurrence of chromosomal and plasmid-mediated beta-lactamases can hinder their accurate molecular detection. We developed a fast and reliable method that allows the typing of isolates carrying more than one SHV gene. The method is based on pyrosequencing the DNA sequence corresponding to amino acid positions 35, 238, and 240.
Use of an In Vitro Pharmacodynamic Model To Derive a Linezolid Regimen That Optimizes Bacterial Kill and Prevents Emergence of Resistance in
Bacillus anthracis
Authors: Louie A. , Heine H. S. , Kim K. , Brown D. L. , VanScoy B. , Liu W. , Kinzig-Schippers M. , Sörgel F. , Drusano G. L.
Published: May 2008

Simulating the average non-protein-bound (free) human serum drug concentration-time profiles for linezolid in an in vitro pharmacodynamic model, we characterized the pharmacodynamic parameter(s) of linezolid predictive of kill and for prevention of resistance in
Bacillus anthracis
. In 10-day dose-ranging studies, the average exposure for ≥700 mg of linezolid given once daily (QD) resulted in >3-log CFU/ml declines in
B. anthracis
without resistance selection. Linezolid at ≤600 mg QD amplified for resistance. With twice-daily (q12h) dosing, linezolid at ≥500 mg q12 h was required for resistance prevention. In dose fractionation studies, killing of
B. anthracis
was predicted by the area under the time-concentration curve (AUC)/MIC ratio. However, resistance prevention was linked to the maximum serum drug concentration (
C
max
)/MIC ratio. Monte Carlo simulations predicted that linezolid at 1,100 mg QD would produce in 96.7% of human subjects a free 24-h AUC that would match or exceed the average 24-h AUC of 78.5 mg·h/liter generated by linezolid at 700 mg QD while reproducing the shape of the concentration-time profile for this pharmacodynamically optimized regimen. However, linezolid at 700 mg q12h (cumulative daily dose of 1,400 mg) would produce an exposure that would equal or exceed the average free 24-h AUC of 90 mg·h/liter generated by linezolid at 500 mg q12h in 93.8% of human subjects. In conclusion, in our in vitro studies, the QD-administered, pharmacodynamically optimized regimen for linezolid killed drug-susceptible
B. anthracis
and prevented resistance emergence at lower dosages than q12h regimens. The lower dosage for the pharmacodynamically optimized regimen may decrease drug toxicity. Also, the QD administration schedule may improve patient compliance.
Molecular Characterization ofEnterococcus faecalisN06-0364 with Low-Level Vancomycin Resistance Harboring a Noveld-Ala-d-Ser Gene Cluster,vanL
Authors: Boyd David A. , Willey Barbara M. , Fawcett Darlene , Gillani Nazira , Mulvey Michael R.
Published: May 2008

Enterococcus faecalisN06-0364, exhibiting a vancomycin MIC of 8 μg/ml, was found to harbor a noveld-Ala-d-Ser gene cluster, designatedvanL. ThevanLgene cluster was similar in organization to thevanCoperon, but the VanT serine racemase was encoded by two separate genes,vanTmL(membrane binding) andvanTrL(racemase).
Sequence of Conjugative Plasmid pIP1206 Mediating Resistance to Aminoglycosides by 16S rRNA Methylation and to Hydrophilic Fluoroquinolones by Efflux
Authors: Périchon Bruno , Bogaerts Pierre , Lambert Thierry , Frangeul Lionel , Courvalin Patrice , Galimand Marc
Published: May 2008

Self-transferable IncFI plasmid pIP1206, isolated from an
Escherichia coli
clinical isolate, carries two new resistance determinants:
qepA
, which confers resistance to hydrophylic fluoroquinolones by efflux, and
rmtB
, which specifies a 16S rRNA methylase conferring high-level aminoglycoside resistance. Analysis of the 168,113-bp sequence (51% G+C) revealed that pIP1206 was composed of several subregions separated by copies of insertion sequences. Of 151 open reading frames, 56 (37%) were also present in pRSB107, isolated from a bacterium in a sewage treatment plant. pIP1206 contained four replication regions (RepFIA, RepFIB, and two partial RepFII regions) and a transfer region 91% identical with that of pAPEC-O1-ColBM, a plasmid isolated from an avian pathogenic
E. coli
. A putative
oriT
region was found upstream from the transfer region. The antibiotic resistance genes
tet
(A),
catA1, bla
TEM-1
,
rmtB
, and
qepA
were clustered in a 33.5-kb fragment delineated by two IS
26
elements that also carried a class 1 integron, including the
sulI, qacE
Δ
1, aad4
, and
dfrA17
genes and Tn
10
, Tn
21
, and Tn
3
-like transposons. The plasmid also possessed a raffinose operon, an arginine deiminase pathway, a putative iron acquisition gene cluster, an
S
-methylmethionine metabolism operon, two virulence-associated genes, and a type I DNA restriction-modification (R-M) system. Three toxin/antitoxin systems and the R-M system ensured stabilization of the plasmid in the host bacteria. These data suggest that the mosaic structure of pIP1206 could have resulted from recombination between pRSB107 and a pAPEC-O1-ColBM-like plasmid, combined with structural rearrangements associated with acquisition of additional DNA by recombination and of mobile genetic elements by transposition.
Analysis of Type II Secretion of Recombinant Pneumococcal PspA and PspC in a
Salmonella enterica
Serovar Typhimurium Vaccine with Regulated Delayed Antigen Synthesis
Authors: Xin Wei , Wanda Soo-Young , Li Yuhua , Wang Shifeng , Mo Hua , Curtiss Roy
Published: May 2008

Recombinant attenuated
Salmonella
vaccines (RASVs) have been used extensively to express and deliver heterologous antigens to host mucosal tissues. Immune responses can be enhanced greatly when the antigen is secreted to the periplasm or extracellular compartment. The most common method for accomplishing this is by fusion of the antigen to a secretion signal sequence. Finding an optimal signal sequence is typically done empirically. To facilitate this process, we constructed a series of plasmid expression vectors, each containing a different type II signal sequence. We evaluated the utilities of these vectors by fusing two different antigens, the α-helix domains of pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC), to the signal sequences of β-lactamase (
bla
SS),
ompA
, and
phoA
and the signal sequence and C-terminal peptide of β-lactamase (
bla
SS+CT) on Asd
+
plasmids under the control of the P
trc
promoter. Strains were characterized for level of expression, subcellular antigen location, and the capacity to elicit antigen-specific immune responses and protection against challenge with
Streptococcus pneumoniae
in mice. The immune responses to each protein differed depending on the signal sequence used. Strains carrying the
bla
SS-
pspA
and
bla
SS+CT-
pspC
fusions yielded the largest amounts of secreted PspA and PspC, respectively, and induced the highest serum IgG titers, although all fusion proteins tested induced some level of antigen-specific IgG response. Consistent with the serum antibody responses, RASVs expressing the
bla
SS-
pspA
and
bla
SS+CT-
pspC
fusions induced the greatest protection against
S. pneumoniae
challenge.
LiaS Regulates Virulence Factor Expression in
Streptococcus mutans
Authors: Chong Patrick , Drake Laura , Biswas Indranil
Published: May 2008

Streptococcus mutans
, a major oral pathogen responsible for dental caries formation, possesses a variety of mechanisms for survival in the human oral cavity, where the conditions of the external environment are diverse and in a constant state of flux. The formation of biofilms, survival under conditions of acidic pH, and production of mutacins are considered to be important virulence determinants displayed by this organism. Biofilm formation is facilitated by the production of GbpC, an important cell surface-associated protein that binds to glucan, an adhesive polysaccharide produced by the organism itself. To better understand the nature of the environmental cues that induce GbpC production, we examined the roles of 14 sensor kinases in the expression of
gbpC
in
S. mutans
strain UA159. We found that only the LiaS sensor kinase regulates
gbpC
expression, while the other sensor kinases had little or no effect on
gbpC
expression. We also found that while LiaS negatively regulates
gbpC
expression, the inactivation of its cognate response regulator, LiaR, does not appear to affect the expression of
gbpC
. Since both
gbpC
expression and mutacin IV production are regulated by a common regulatory network, we also tested the effect of the
liaS
mutation on mutacin production and found that LiaS positively regulates mutacin IV production. Furthermore, reverse transcription-PCR analysis suggests that LiaS does so by regulating the expression of
nlmA
, which encodes a peptide component of mutacin IV, and
nlmT
, which encodes an ABC transporter. As with the expression of
gbpC
, LiaR did not have any apparent effect on mutacin IV production. Based on the results of our study, we speculate that LiaS is engaged in cross talk with one or more response regulators belonging to the same family as LiaR, enabling LiaS to regulate the expression of several genes coding for virulence factors.
Application of Capillary Electrophoresis Mass Spectrometry and Liquid Chromatography Multiple-Step Tandem Electrospray Mass Spectrometry To Profile Glycoform Expression during
Haemophilus influenzae
Pathogenesis in the Chinchilla Model of Experimental Otitis Media
Authors: Lundström Susanna L. , Li Jianjun , Månsson Martin , Figueira Marisol , Leroy Magali , Goldstein Richard , Hood Derek W. , Moxon E. Richard , Richards James C. , Schweda Elke K. H.
Published: May 2008

Otitis media caused by nontypeable
Haemophilus influenzae
(NTHi) is a common and recurrent bacterial infection of childhood. The structural variability and diversity of
H. influenzae
lipopolysaccharide (LPS) glycoforms are known to play a significant role in the commensal and disease-causing behavior of this pathogen. In this study, we determined LPS glycoform populations from NTHi strain 1003 during the course of experimental otitis media in the chinchilla model of infection by mass spectrometric techniques. Building on an established structural model of the major LPS glycoforms expressed by this NTHi strain in vitro (M. Månsson, W. Hood, J. Li, J. C. Richards, E. R. Moxon, and E. K. Schweda, Eur. J. Biochem. 269:808-818, 2002), minor isomeric glycoform populations were determined by liquid chromatography multiple-step tandem electrospray mass spectrometry (LC-ESI-MS

n

). Using capillary electrophoresis ESI-MS (CE-ESI-MS), we determined glycoform profiles for bacteria from direct middle ear fluid (MEF) samples. The LPS glycan profiles were essentially the same when the MEF samples of 7 of 10 animals were passaged on solid medium (chocolate agar). LC-ESI-MS

n

provided a sensitive method for determining the isomeric distribution of LPS glycoforms in MEF and passaged specimens. To investigate changes in LPS glycoform distribution during the course of infection, MEF samples were analyzed at 2, 5, and 9 days postinfection by CE-ESI-MS following minimal passage on chocolate agar. As previously observed, sialic acid-containing glycoforms were detected during the early stages of infection, but a trend toward more-truncated and less-complex LPS glycoforms that lacked sialic acid was found as disease progressed.
Characterization of a
Helicobacter hepaticus putA
Mutant Strain in Host Colonization and Oxidative Stress
Authors: Krishnan Navasona , Doster Alan R. , Duhamel Gerald E. , Becker Donald F.
Published: May 2008

Helicobacter hepaticus
is a gram-negative, spiral-shaped microaerophilic bacterium associated with chronic intestinal infection leading to hepatitis and colonic and hepatic carcinomas in susceptible strains of mice. In the closely related human pathogen
Helicobacter pylori
,
l
-proline is a preferred respiratory substrate and is found at significantly high levels in the gastric juice of infected patients. A previous study of the proline catabolic PutA flavoenzymes from
H. pylori
and
H. hepaticus
revealed that
Helicobacter
PutA generates reactive oxygen species during proline oxidation by transferring electrons from reduced flavin to molecular oxygen. We further explored the preference for proline as a respiratory substrate and the potential impact of proline metabolism on the redox environment in
Helicobacter
species during host infection by disrupting the
putA
gene in
H. hepaticus
. The resulting
putA
knockout mutant strain was characterized by oxidative stress analysis and mouse infection studies. The
putA
mutant strain of
H. hepaticus
exhibited increased proline levels and resistance to oxidative stress relative to that of the wild-type strain, consistent with proline's role as an antioxidant. The significant increase in stress resistance was attributed to higher proline content, as no upregulation of antioxidant genes was observed for the
putA
mutant strain. The wild-type and
putA
mutant
H. hepaticus
strains displayed similar levels of infection in mice, but in mice challenged with the
putA
mutant strain, significantly reduced inflammation was observed, suggesting a role for proline metabolism in
H. hepaticus
pathogenicity in vivo.
A heat acclimation protocol for team sports
Authors: Sunderland C , Morris J G , Nevill M E
Published: May 2008

Background:

It is well documented that heat acclimation of six or more sessions of at least 60 min duration prolongs the time to exhaustion during endurance walking, cycling and running in the heat. However, this type of acclimation is not specific to team sport activity and the effect of acclimation on prolonged high-intensity intermittent running has not yet been investigated.

Objective:

To assess the impact of an intermittent acclimation protocol on distance run during team sport activity.

Methods:

The impact of four short heat acclimation sessions (30–45 min of the Loughborough Intermittent Shuttle Test; LIST) on high-intensity intermittent running capacity (LIST) in the heat (30°C, 27% relative humidity (RH)), was examined. Seventeen female well-trained games players were split into three groups: an acclimation group (30°C, 24% RH), a moderate training group (18°C, 41% RH) and a control group who did not complete any training between the main trials (pre-acclimation and post-acclimation). The pre-acclimation (A) and post-acclimation (B) trials were separated by 28 days to control for menstrual phase and verified using hormonal analysis. The four acclimation or moderate training sessions utilising the LIST were completed with one or two rest days interspersed between each session in a 10-day period prior to the post-acclimation trial (B).

Results:

In the post-acclimation trial distance run was increased by 33% in the acclimation group (A: 7703 (SEM 1401) m vs B: 10215 (SEM 1746) m; interaction group × trial p<0.05), but was unchanged in the moderate and control groups. The acclimation group had a lower rectal temperature (interaction group × trial × time p<0.01) due to a lower rate of rise, and an increase in thermal comfort1 after acclimation (End A: 7 (SEM 2) vs 6 (SEM 2); interaction group × trial p<0.01). There was no difference in serum progesterone, aldosterone or cortisol concentrations following acclimation or between groups.

Conclusion:

Four 30–45 min sessions of intermittent exercise induced acclimation, and resulted in an improvement in intermittent running exercise capacity in female games players. A lower rectal temperature and a concomitant rise in thermal comfort may be partly responsible for the improvement in exercise capacity.
Discovery, measurement, and interpretation of diversity in arbuscular endomycorrhizal fungi (Glomales, Zygomycetes)
Authors: Morton Joseph B. , Bentivenga Stephen P. , Bever James D.
Published: May 2008

Measures of diversity depend on an eclectic taxonomy now being developed from comparisons of morphology, developmental programs, carbohydrate chemistry, fatty acids, and nucleotide sequences in a wide range of arbuscular fungal taxa obtained from living culture collections. Developmental patterns in character origin and transformation are providing clues of intrinsic causation in evolution of diversity. Extrinsic causation is being identified from population-level dynamics, as well as data on species numbers, abundance, composition, and distribution. Detection of species is based solely on sporulation, so that a combination of field sampling and various trap culture methods provide a more comprehensive estimate of fungal community organization. Species distributions rarely correlate with ecological gradients or hypothesized phylogenetic relationships, suggesting that an important causal factor of present-day distributions is dispersal over geologic time. Global distribution of both derived and ancestral species and representation of all genera in most plant root systems further indicate that local diversity has a strong historical component, with ecological processes of subordinate consequence. Ecological dynamics play a crucial role at the local level. They are governed by multilevel diversity among and within organisms of a species assemblage, such as differences in life history traits and heterogeneity of genetic and physiological properties, respectively. Key words: ecology, phylogeny, systematics, vesicular – arbuscular mycorrhizae.
Old and new ways to probe plant cell-wall architecture
Authors: McCann Maureen C. , Roberts Keith , Wilson Reginald H. , Gidley Michael J. , Gibeaut David M. , Kim Jong-Bum , Carpita Nicholas C.
Published: May 2008

Wall structure has been analysed by a process of careful demolition, in which chemical extradants are used to remove specific polymers for sugar and linkage analysis, gel-permeation or ion-exchange chromatography, and nuclear magnetic resonance spectroscopy. Sequence-dependent endoglycanases cleave certain polysaccharides into oligomers that can be sequenced completely and give a clear picture of the repetitive units used to make fundamental polymers. We have also developed and adapted new chemical procedures and pulse-labelling techniques to give more information on the ways that wall polymers are subtly modified during growth. In this report, we review these conventional means of carbohydrate analyses together with newer methods of selective enzymic hydrolysis, separation of large oligosaccharides by high pH anion-exchange chromatography, and detection of molecular mass of several thousand daltons by electrospray mass spectrometry. These new technologies have already given much valuable information about the polymeric building blocks, but little information on how these polymers are arranged in space. For this, we adapted new cryopreservation techniques for electron microscopy that can image the wall in as close to the in vivo state as possible. In addition to defining anomeric linkages and linkage structures in preparations of native polymers, nuclear magnetic resonance spectroscopy can also determine the relative mobility of particular polymers within the structure of hydrated cell walls. The generation of antibodies to particular cell wall epitopes has enabled us to define architectural differences among species, among tissue types, and even among domains within a single wall. Our awareness of the diversity and complexity of primary cell wall architecture has driven a search for methodologies such as Fourier transform infrared and Fourier transform Raman microspectroscopies, which are suitable for analysis at the single cell wall level. Key words: cell walls, polysaccharides, gas – liquid chromatography – mass spectrometry, Fourier transform infrared microspectroscopy, nuclear magnetic resonance spectroscopy, immunocytochemistry.
Carbon catabolite repression inAspergillus nidulans: a review
Authors: Scazzocchio Claudio , Gavrias Victoria , Cubero Beatriz , Panozzo Cristina , Mathieu Martine , Felenbok Béatrice
Published: May 2008

We describe the experimental methodology that led to the discovery of the creA gene in Aspergillus nidulans. This gene codes for a transcriptional repressor mediating carbon catabolite repression in many pathways in this organism. We compare both the mode and the mechanism of action in two pathways subject to CreA-mediated repression. The genes comprising the ethanol regulon are subject to carbon catabolite repression independently of the nitrogen source, while the genes involved in proline utilization are repressed by glucose only when a repressing nitrogen source is also present. In the ethanol regulon, CreA drastically represses the expression of the positive regulatory gene alcR, thus preventing the expression of the structural genes. Direct repression of the structural genes is also existant. In the proline utilization pathway, repression operates directly at the level of the structural genes. In the ethanol regulon, CreA prevents the self-induction of alcR and the induction of the structural genes by competing with the binding of the AlcR protein. In proline gene cluster, CreA does not interfere with induction mediated by PrnA but with the activity of an unknown and more general transcription factor. Key words: carbon catabolite repression, ascomycetes, Zn fingers.
Plasmids in natural populations ofNeurospora
Authors: Griffiths A. J. F. , Yang X. , Debets F. J. , Wei Y.
Published: May 2008

Eukaryotic plasmids are mainly fungal. Global Neurospora populations have been surveyed and show that approximately half the isolates have one or more plasmids. There are distinct homology groups of plasmids and most groups are distributed across species. One example is also in a related genus, Gelasinospora. Most plasmids are apparently benign but several examples are virulent, killing by insertion into mtDNA. In Hawaii, one of the virulent plasmids, kalilo, might be increasing in frequency. Plasmids can be transmitted horizontally between laboratory strains by forced heterokaryosis or by transient fusion. Simulations of population transmission have shown that the linear kalilo and circular Hanalei-2 plasmids are aggressively transmitted from one compatible prototroph to another. This transmission is slowed but not necessarily eliminated by het gene incompatibility. Paternal transmission of plasmids has been demonstrated and this seems to be affected by the incompatibility genotypes of the parents. However, paternal transmission might not be through the normal trichogyne route, but by a "back-door" route possibly through maternal mycelium. There are several documented ways in which plasmids can change their structure. One novel way is by recombination between two different heterologous plasmids. These processes might be relevant to plasmid evolution. Two suppression processes have been discovered that can be used by the host to eliminate specific plasmids: a cell autonomous type, and a nonautonomous type that acts during the sexual cycle. In conclusion, plasmids are diverse and widely distributed in fungi, undoubtedly reflecting their multiple modes of transmission and structural modification. Key words: Neurospora, plasmids, mitochondria, populations, kalilo.
Meiotic mutants and DNA repair genes ofCoprinus cinereus
Authors: Zolan Miriam E. , Stassen Natalie Yeager , Ramesh Marilee A. , Valentine Gerald , Lu Benjamin C.
Published: May 2008

We are studying DNA repair and meiosis in the basidiomycete Coprinus cinereus, in which the meiotic cycle is naturally highly synchronous. We have taken two approaches to the study of genes whose products function in these essential and related processes. In the first, we screened mutagenized cultures for γ-radiation sensitivity and recovered four complementation groups, rad3, rad9, rad11, and rad12, that are required for the survival of γ-irradiation and for meiosis. These four genes are in the same pathway for survival of γ-radiation damage. Surface spreads of meiotic chromosomes of rad3, rad9, and rad12 mutants demonstrated that both axial core development and chromosome synapsis are defective. The rad3-4 mutant exhibits heterogeneity in the appearance of its meiotic cells, which may reflect stochastic effects of the absence of functional rad3 gene product, or cell to cell variation of the abundance of the rad3 protein within the mutant. All four of the rad genes necessary for meiosis have been mapped to the electrophoretic karyotype of C. cinereus, and the rad9 gene has been cloned. In a second approach to the study of DNA repair and meiosis, we have used PCR to isolate the gene Ccrad51, a homolog of the prokaryotic gene recA. Although the precise functions of these genes in DNA repair and meiosis are not known, we hypothesize that their roles in these two fundamental processes are similar, and that this group of genes was recruited during evolution for the application of mitotic DNA repair functions to the metabolism of meiotic chromosomes. Key words: DNA repair, meiosis, Coprinus cinereus, synapsis.
Mating type control of sexual development inCoprinus cinereus
Authors: Casselton L. A. , Asante-Owusu R. N. , Banham A. H. , Kingsnorth C. S. , Kües U. , O'shea S. F. , Pardo E. H.
Published: May 2008

The multiallelic mating type genes of the hymenomycete fungus Coprinus cinereus determine mating compatibility by regulating a developmental sequence that converts an asexual monokaryon into a fertile dikaryon. The genes map to two loci, A and B, and mating compatibility requires different alleles of genes at both loci. The A genes encode two classes of proteins with conserved but dissimilar homeodomain DNA binding motifs (HD1 and HD2), which identify their role in development as transcriptional regulators. Transformation studies with cloned genes suggest that a compatible mating is sensed by combinatorial interactions between an HD1 and HD2 protein and that the N-terminal regions of these proteins are implicated in the specificity of this interaction. The B genes of C. cinereus have been cloned but their function is, as yet, unknown. In another species, Schizophyllum commune, the B genes encode pheromones and pheromone receptors. Although a pheromone response pathway is not apparent in cell fusion in hymenomycetes, it now seems likely to be involved in maintenance of dikaryotic growth. Key words: Coprinus, hymenomycete, mating type, homeodomain proteins, pheromones and receptors, sexual development.
Genetic regulation of emergent growth in Schizophyllum commune
Authors: Wessels J. G. H. , Ásgiersdóttir S. A. , Birkenkamp K. U. , Vries O. M. H. de , Lugones L. G. , Scheer J. M. J. , Schuren F. H. J. , Schuurs T. A. , Wetter M. A. van , Wösten H. A. B.
Published: May 2008

After a period of juvenile growth, Schizophyllum commune starts to transcribe genes for a number of abundant cell-wall proteins that are excreted into the medium by submerged hyphae but become part of the cell wall in emergent structures. The dikaryon transcribes the genes SC1, SC3, SC4, and SC6 that encode hydrophobins and SC7 and SC14 that encode hydrophilic wall proteins of unknown function. Of these, only the SC3 gene is highly transcribed in the monokaryon. The SC3p hydrophobin forms an insoluble hydrophobic rodlet layer by interfacial self-assembly at the outer surface of aerial hyphae of both monokaryon and dikaryon. The SC4p hydrophobin forms an insoluble membrane separating the extracellular matrix surrounding dikaryotic hyphae of the plectenchyma from air cavities in the fruit bodies while the product of the SC7 gene is found within the extracellular matrix. However, these plectenchyma hyphae do not express the SC3 gene. Because SC3 activity is suppressed in a MATA = MATB≠ heterokaryon and a MATAx matBCon homokaryon, interaction between different B mating-type gene products appears responsible for suppression of SC3 in the hyphae that form the plectenchyma. On the other hand, in aerial hyphae of the MATA ≠ MATB≠ heterokaryon the binucleate state of the hyphae appears disrupted and this is accompanied by expression of SC3 only, as in the monokaryon. This suggests that regulation of specific genes by the products of different MATB genes only occurs when these genes are present in closely paired nuclei. Thus, spatial differences in gene expression during emergent growth in the MATA ≠ MATB≠ heterokaryon may occur by regulation of the nuclear distribution. Key words: Schizophyllum commune development, hydrophobins in development, mating-type genes in Schizophyllum, fruit-body development, emergent growth.
Gibberella fujikuroi: available populations and variable traits
Authors: Leslie John F.
Published: May 2008

Gibberella fujikuroi is a complex species comprised of at least seven distinct mating populations (biological species) with Fusarium anamorphs. These fungi are common pathogens of maize, rice, and sorghum and cause billions of dollars of losses in these crops worldwide. Mating populations are biological species defined by cross-fertility of members of the same mating population with one another, and sterility whenever members of two different mating populations are crossed. Mating populations also differ in their electrophoretic karyotypes, their general ability to synthesize secondary metabolites, and their sensitivity to antifungal agents such as benomyl and hygromycin B. Within a mating population strains can be distinguished on the basis of their ability to form a heterokaryon with one another. This polygenic trait has been used to study the structure of some populations of these fungi. In some cases, pathogenic strains appear to be clones that are limited to a crop and (or) geographic location. More commonly, however, there is significant genetic variability present and sexual reproduction appears to be playing an important role in assorting that variability to different individuals. Key words: Fusarium moniliforme, Fusarium proliferatum, Fusarium subglutinans, population genetics, maize, sorghum.
The Golgi complex ofSaccharomyces cerevisiae
Authors: Krasnov Vladimir , Graham Todd R.
Published: May 2008

The Golgi complex of Saccharomyces cerevisiae is required for protein transport, posttranslational modification, and sorting within the secretory pathway. Only in the last few years has it become clear that these events are functionally organized into distinct Golgi compartments analagous to the cis–trans compartments of the plant and animal Golgi complex. The mechanisms by which the Golgi complex maintains its own organization and complement of intrinsic enzymes against the flow of lipid and protein through the secretory pathway are still poorly understood. However, studies using Saccharomyces cerevisiae as a model system are providing insights into mechanisms of Golgi protein localization that appear to be conserved between yeast and mammalian cells. This review describes the structure and organization of the yeast Golgi complex and recent work towards defining localization signals within intrinsic enzymes of this organelle. Key words: Golgi complex, protein sorting, Saccharomyces cerevisiae, α-1,3-mannosyltransferase.
The role of the cytoskeleton in the movement and positioning of nuclei inCoprinus cinereus
Authors: Kamada Takashi , Tanabe Shigeru
Published: May 2008

Coprinus cinereus exhibits conspicuous nuclear movement and precise nuclear positioning during its life cycle. Examples include transhyphal migration of nuclei in compatible mating giving rise to a dikaryon, nuclear positioning relative to the hyphal apex in the dikaryon, the close spacing in interphase and conjugate division of the two nuclei in the dikaryon, and the migration of nuclei from the basidium into developing spores. We have investigated the roles of the cytoskeleton in these processes using cytoskeleton mutants as well as fluorescence microscopy. Some of the α1- and β1-tubulin mutations examined blocked nuclear migration in dikaryosis and disturbed nuclear pairing in the dikaryon, demonstrating that microtubules are involved in these processes. The same mutations, however, did not affect the positioning of nuclei in interphase nor in conjugate division in the dikaryon, nor the migration of nuclei into the developing spores. Immunofluorescence microscopy revealed that these mutations inhibit the formation of asters of the mitotic apparatus in conjugate division, providing evidence against direct involvement of astral microtubules in nuclear movement during conjugate division. Actin was concentrated in hyphal regions where the nuclei sit in early phases of conjugate division, suggesting the involvement of actin in conjugate division. Key words: Coprinus cinereus, dikaryon, nuclear movement, microtubules, aster, actin.
Motor proteins in Saccharomyces cerevisiae
Authors: Brown Susan S.
Published: May 2008

A number of myosins have been identified in yeast (Saccharomyces cerevisiae), an organism ideally suited to dissecting out their different functions. We have learned that a temperature-sensitive defect in one of these myosins (Myo2p) can be partially overcome by overexpression of a kinesin-like protein (Smy1p). This raises the possibility of the involvement of microtubules in the same function as Myo2p. However, we have been unable to demonstrate that this is the case, either using nocodazole to depolymerize microtubules or by altering the nucleotide-binding site of Smy1p. Key words: myosin, kinesin-related protein, cytoskeleton.
Polarity of vesicle distribution in oomycete zoospores: development of polarity and importance for infection
Authors: Hardham A. R.
Published: May 2008

Biflagellate zoospores are the major infective agent for many pathogenic species of Oomycetes. Over the last 10 years, the use of a range of immunological techniques has greatly expanded our understanding of the ultrastructure of these cells and of the role a number of cell components play in the infection of a host. Three types of vesicles that occur in the peripheral cytoplasm of the zoospores have been well characterized. These vesicles show distinct polarities in their distribution within the zoospore cortex. Two are secretory and are thought to be responsible for the formation of the cyst coat and the deposition of adhesive material during encystment and host infection. The third vesicle type is not secreted and appears to serve as a store of proteins used to support early germling growth. All three vesicles are formed by the Golgi apparatus in hyphae following the induction of sporulation. They move into sporangia developing at the hyphal apex and are randomly distributed in the forming and mature sporangia. After the induction of sporangial cleavage, the vesicles are sorted into domains adjacent to the newly formed zoospore plasma membrane. This final sorting is dependent in some way on an intact microtubular cytoskeleton. Vesicle targeting and sorting is thus temporally and spatially removed from vesicle synthesis. Features of the oomycete zoospore system promise to make it a valuable one in which to conduct further studies of vesicle targeting, polarized secretion, and the role of the cytoskeleton in these processes. Key words: cytoskeleton, immunocytochemistry, Phytophthora, regulated secretion, sporulation.
Infection-induced rapid cell death in plants: a means of efficient pathogen defense
Authors: Schmelzer Elmon , Naton Beatrix , Freytag Sibylle , Rouhara Ila , Küster Bernhard , Hahlbrock Klaus
Published: May 2008

The hypersensitive reaction represents one of the major means by which plants actively defend themselves against infection by pathogenic bacteria, fungi, viruses, and nematodes. This complex defense reaction, often associated with the synthesis of phytoalexins (antimicrobial secondary metabolites), involves at the cellular level highly dynamic cytoplasmic rearrangements, rapid metabolic changes, and finally cell death. It also correlates with the rapid and transient activation of various defense-related genes in a region of tissue surrounding infection sites and later, with the systemic increase in expression of a number of other genes. Examination of the reactions of individual living cells of potato leaves infected with Phytophthora infestans enabled the comprehensive description of the dynamic aspects of all stages of the defense response. Cytochemical investigations, employing cultured cells of parsley infected with P. infestans as a versatile model system, have contributed to a better understanding of cytoplasmic and metabolic processes occurring during the defense response, and suggest that hypersensitive cell death requires the preceding activation of respiration and specific metabolic pathways. Key words: defense responses, defense-related genes, hypersensitive reaction, programmed cell death.