bluuebunny/crossref_metadata_2025 huggingface dataset:
An update on the synthetic collagenous artificial cornea
Authors: FAGERHOLM P , GRIFFITH M
Published: October 2007

During embryonic development, cells secrete an extracellular matrix (ECM) around themselves that is turn provides cues to the cells to direct organ development. The same ECM componants would therefore also be likely to direct repair and regeneration of these organs. Our goal, therefore, was to develop biomimetic materials that are ECM analogs, capable of sustaining a native‐like ECM environment and interacting with host tissues and stem cells to effect regeneration.

Specifically for the cornea, we have successfully completed a 12 month study on corneal substitutes fabricated from recombinant human collagen that were implanted into mini‐pigs be lamellar keratoplasty. Implants made from type I and type III recombinant collagens were compared. Both collagens could be crosslinked and moulded into the shape and size of human corneas. While we found that type III implants had a tendency to be mechanically stronger, both types of implants gave very similar results. They retained optical clarity by both slit lamp biomicroscopy and fundus imaging. They also retained their thickness indicating graft stability. Regeneration of corneal epithelial and stromal cells were also observed. In addition, corneal nerves and the tear film were regenerated. These results were comparable to those we had previously reported in shorter term studies. These recombinant collagens, as thin sheets, were also found to be suitable as scaffolds for proliferation of human corneal limbal cells.

As the collagen source is recombinant, made from yeast, we have therefore shown that completely man‐made corneal substitutes can be produced as substitutes of the corneal matrix. Biomimetic materials, therefore, are likely to be successful for reproducing the natural scaffolding in tissue engineering applications, such as the development of corneal substitutes.
AER lecture: Some reflections on corneal thickness
Authors: EHLERS N
Published: October 2007

The corneal thickness as an object for studies was recognized in the renaissance. A value of 1 mm, representing the maximally swollen human cornea, was reported. Optical in vivo measurements were done by Blix in 1880 reporting a thickness of about 0.5 mm, the value that we today know is correct.

Blix lived in “the golden age of physiologic optics”. His interest was the contribution of the cornea to the optical refraction of the eye, and was thus the distance between the anterior and the posterior surface rather than the thickness of the cornea as such.

A biomechanical interest in corneal thickness was initiated by the studies of tonometry, in particular Hans Goldmann’s development of applanation tonometry. He predicted correctly that corneal thickness would influence the estimated pressure reading.

Another physiological aspect of the cornea is its transparency. Earlier explanations by equal refractive index was revolutionized by the interference theory by David Maurice. Optical transparency required a regular fiber pattern, and thus a stabilized thickness and stromal hydration. This led to extensive interest in the permeability of the limiting layers, in particular the transport of fluid across the endothelium. The physiological concepts required a regulated or stabilized thickness. The thickness as such became interesting.

The human cornea is thinner in the center than more peripherally and the central, presumably regulated central thickness (CCT) became a biometric and clinical study object. The exact individual value became of interest. Several optical and later ultrasonic principles were presented.

Questions addressed were: Is CCT a life‐long, age independent characteristics. Is CCT diagnostic for certain disease conditions (e.g. Macular dystrophy of Groenouw). Is CCT a useful clinical parameter to follow disease processes (e.g. progression in keratoconus or acute changes in graft rejections).

Today refractive surgery has revived the interest in biomechanical and optical properties of the cornea. Modern computer technology allows for a description of the “thickness profile” of the entire cornea. This gives us access to an overwhelming amount of data, and reopen many issues of the past. We must realize, however, that what we see is the pendulum swinging back to the problems of the last century. The machinery is smarter but many of the basic questions remain to be solved.
EVER Lecture: Can uveal melanoma be conquered?
Authors: KIVELÄ T
Published: October 2007

The deadly natural history of uveal melanoma was fully described, unknowingly, in a well known English artist in 1792 and soon thereafter in an unknown Scottish woman around 1808. It became a well recognised entity much later, by 1868. Today, with the exception of being able to save the eye of their patient, ocular oncologists managing patients with uveal melanoma find themselves in essentially the same situation than their forebears: mortality rates have not noticeably decreased and metastatic melanoma continues to be the “hideous picture of disease” that it was 150 years ago. Metastatic melanoma is the single overwhelming cause of death in patients with uveal melanoma, and no consistently effective treatment is known for disseminated disease. One reason for this unhappy state of affairs is that patients formerly were dismissed after enucleation until they presented with advanced metastasis to an oncologist who did not recognise uveal melanoma as a disease very different from cutaneous melanoma. The advent of ocular oncology has led to rational early detection programs for subclinical metastasis, validated staging of metastatic disease, and first controlled clinical trials of managing metastases with therapies specifically aimed against this cancer. Basic research highlights uveal melanoma as a typically slowly growing, early metastasising cancer, and staging, grading and typing of primary tumours is leading to rational assignment of patients to follow‐up and adjuvant treatment trials, which hopefully will improve their survival rate. The current understanding is that, by the time the eye becomes symptomatic, uveal melanomas prone to metastasis already have seeded micrometastases, which need to be kept under control if we are to eventually conquer this disease.
Delivery of Eye Care in Developing Countries ‐ Role of Research
Authors: RAO G
Published: October 2007

Purpose: To present the information and problems of global blindness and how research can help in addressing these problems.

Methods: Blindness is a serious public health problem in developing countries. Most (almost 90 percent) of avoidable – preventable and treatable – blindness exists in the developing countries of the world. Through a variety of innovations, based on epidemiological and operations research, innovative models of eye care delivery have been developed to make eye care effective and cost‐effective. The next step is large scale replication with appropriate local modifications. A challenge before the research community is to extend the scope of translational research from the traditional “laboratory to the clinic” mode to an enhanced version of “laboratory to clinic to community” mode.

Results: The eye care delivery model should encompass all levels of care from the primary to advanced tertiary with clear delineation of functions at every level, referral linkages, without compromising on quality or equity and making programmes sustainable.

While prevention strategies against trachoma and onchocerciasis are successful and tackling cataract problem is getting better, the more complex issues of glaucoma and diabetic retinopathy are looming large. Significant attention has to be paid to develop appropriate public health and clinical approaches to control blindness from these problems too if VISION 2020: The Right to Sight has to realize the aspiration of controlling global blindness to a significant degree by 2020.

Conclusions: Global cooperation and collaboration may be the key to arrive at solutions in an accelerated manner given the environment of increasingly limited resources and competing demands.
Antigen‐presenting cells and the eye
Authors: JAGER MJ
Published: October 2007

Antigen‐presenting cells (APC) carry many different functions such as phagocytosis, antigen processing, antigen presentation. Depending on the nature of the APC, presentation of an antigen may lead to an active immune response, or lead to inhibition of the specific immune response. Some ocular subjects where APCs are of special interest are corneal immune responses, e.g against viral infections, the development of ACAID (anterior chamber associated immune deviation), and tumor immunology. In the last case, a good response might help the patient survive, but the development of an inferior response might suppress any useful anti‐tumor responses. These controversies will be discussed.
From Helmholtz to the scanning laser ophthalmoscope. 150 years of ophthalmoscopy.
Authors: DE LAEY JJ
Published: October 2007

Purpose: To give a brief overview on Helmholtz and the history of ophthalmoscopy.

Methods: Literature survey.

Results: Hermann von Helmholtz (1821‐1894), although not an ophthalmologist but a physiologist, invented the ophthalmoscope, not yet 30 years old, and is thus one of the most important scientists in European ophthalmology.Yet Charles Bobbage may have preceeded Helmholtz. Unfortunately an "expert" gave him a negative critic and his work was only published in 1854, 3 years after Helmholtz's monography: "Beschreibung einer Augenspiegels zur Untersuchung des Netzhaut im lebenden Auge". Helmholtz's discovery as well as the first international congress of Ophthalmology exactly 150 years ago, introduced the modern era of ophthalmology. Within a few years several modifications of Helmholtz's ophthalmoscope were presented by Ruete (1852), Coccius (1853 and 1855), Anagnostakis (1854), Gillet de Grandmont (1859),Galezowski (1862), Beale (1869) and others. Marc‐Antoine Giraud‐Teulon (1861) designed the first binocular ophthalmoscope. The first coloured drawing of the fundus was published in Utrecht in 1853 (Van Tricht) and Fallon (1863) published the first atlas of ophthalmoscopy.

Conclusions: Despite limitations due to poor illumination the introduction of ophthalmoscopy resulted in the discovery of a completely new field in ophthalmology.
Antimicrobial Drug Resistance of
Salmonella enterica
Serovar Typhi in Asia and Molecular Mechanism of Reduced Susceptibility to the Fluoroquinolones
Authors: Chau Tran Thuy , Campbell James Ian , Galindo Claudia M. , Van Minh Hoang Nguyen , Diep To Song , Nga Tran Thu Thi , Van Vinh Chau Nguyen , Tuan Phung Quoc , Page Anne Laure , Ochiai R. Leon , Schultsz Constance , Wain John , Bhutta Zulfiqar A. , Parry Christopher M. , Bhattacharya Sujit K. , Dutta Shanta , Agtini Magdarina , Dong Baiqing , Honghui Yang , Anh Dang Duc , Canh Do Gia , Naheed Aliya , Albert M. John , Phetsouvanh Rattanaphone , Newton Paul N. , Basnyat Buddha , Arjyal Amit , La Tran Thi Phi , Rang Nguyen Ngoc , Phuong Le Thi , Van Be Bay Phan , von Seidlein Lorenz , Dougan Gordon , Clemens John D. , Vinh Ha , Hien Tran Tinh , Chinh Nguyen Tran , Acosta Camilo J. , Farrar Jeremy , Dolecek Christiane
Published: October 2007

This study describes the pattern and extent of drug resistance in 1,774 strains of
Salmonella enterica
serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83→Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in
gyrB
,
parC
, or
parE
were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.
Antileishmanial Structure-Activity Relationships of Synthetic Phospholipids: In Vitro and In Vivo Activities of Selected Derivatives
Authors: Seifert Karin , Lemke Andreas , Croft Simon L. , Kayser Oliver
Published: October 2007

Antileishmanial activities of 91 synthetic phospholipids against
Leishmania donovani
were evaluated in vitro and cytotoxicity assessed against two mammalian cell lines. Promising compounds were tested further in vivo. In vitro structure-activity relationships showed a positive contribution of head groups bearing ring systems (
N
-methylpiperidino and
N
-methylmorpholino) to antileishmanial activity.
In Vitro Susceptibility of Methicillin-Resistant
Staphylococcus aureus
and Methicillin-Susceptible
Staphylococcus aureus
to a New Antimicrobial, Copper Silicate
Authors: Carson Kerry C. , Bartlett Jessica G. , Tan Trina-Jean , Riley Thomas V.
Published: October 2007

The soluble copper silicate (CS) MIC of 100 strains of methicillin-resistant
Staphylococcus aureus
and 100 strains of methicillin-susceptible
S. aureus
(MSSA) was 175 mg Cu/liter. Bactericidal and postantibiotic effects (≥1 h) were seen at 2× MIC and 4× MIC. The frequency of mutation was <10
−9
, and serial passage could not extend growth beyond 1.6× MIC.
A MurF Inhibitor That Disrupts Cell Wall Biosynthesis in
Escherichia coli
Authors: Baum Ellen Z. , Crespo-Carbone Steven M. , Klinger Alexandra , Foleno Barbara D. , Turchi Ignatius , Macielag Mark , Bush Karen
Published: October 2007

MurF is an essential enzyme of bacterial cell wall biosynthesis. Few MurF inhibitors have been reported, and none have displayed measurable antibacterial activity. Through the use of a MurF binding assay, a series of 8-hydroxyquinolines that bound to the
Escherichia coli
enzyme and inhibited its activity was identified. To derive additional chemotypes lacking 8-hydroxyquinoline, a known chelating moiety, a pharmacophore model was constructed from the series and used to select compounds for testing in the MurF binding and enzymatic inhibition assays. Whereas the original diverse library yielded 0.01% positive compounds in the binding assay, of which 6% inhibited MurF enzymatic activity, the pharmacophore-selected set yielded 14% positive compounds, of which 37% inhibited the enzyme, suggesting that the model enriched for compounds with affinity to MurF. A 4-phenylpiperidine (4-PP) derivative identified by this process displayed antibacterial activity (MIC of 8 μg/ml against permeable
E. coli
) including cell lysis and a 5-log
10
-unit decrease in CFU. Importantly, treatment of
E. coli
with 4-PP resulted in a 15-fold increase in the amount of the MurF UDP-MurNAc-tripeptide substrate, and a 50% reduction in the amount of the MurF UDP-MurNAc-pentapeptide product, consistent with inhibition of the MurF enzyme within bacterial cells. Thus, 4-PP is the first reported inhibitor of the MurF enzyme that may contribute to antibacterial activity by interfering with cell wall biosynthesis.
In Vitro Resistance Study of Rupintrivir, a Novel Inhibitor of Human Rhinovirus 3C Protease
Authors: Binford S. L. , Weady P. T. , Maldonado F. , Brothers M. A. , Matthews D. A. , Patick A. K.
Published: October 2007

Rupintrivir (formerly AG7088) is an irreversible inhibitor of the human rhinovirus (HRV) 3C protease that has been demonstrated to have in vitro activity against all HRVs tested, consistent with its interaction with a strictly conserved subset of amino acids in the 3C protease. The potential for resistance was studied following in vitro serial passage of HRV serotypes 14, 2, 39, and Hanks in the presence of increasing rupintrivir concentrations. HRV variants with reduced susceptibilities to rupintrivir (sevenfold for HRV 14) or with no significant reductions in susceptibility but genotypic changes (HRV 2, 39, and Hanks) were initially isolated following 14 to 40 cumulative days in culture (three to six passages). Sequence analysis of the 3C protease identified one to three substitutions in diverse patterns but with common features (T129T/A, T131T/A, and T143P/S in HRV 14; N165T in HRV 2; N130N/K and L136L/F in HRV 39; T130A in HRV Hanks). Notably, three of the four HRV variants contained a substitution at residue 130 (residue 129 in HRV 14). Continued selection in the presence of escalating concentrations of rupintrivir (40 to 72 days) resulted in the accumulation of additional mutations (A121A/V and Y139Y/H in HRV 14, E3E/G and A103A/V in HRV 2, S105T in HRV 39), with only minimal further reductions in susceptibility (up to fivefold). The ability of specific substitutions to confer resistance was examined by susceptibility testing of HRV 14 variants constructed to contain 3C protease mutations. In summary, the slow accumulation of multiple amino acid substitutions with only minimal to moderate reductions in susceptibility highlight the advantages of 3C protease as an antiviral target.
The p38 Mitogen-Activated Protein Kinase Signaling Pathway Is Coupled to Toll-Like Receptor 5 To Mediate Gene Regulation in Response toPseudomonas aeruginosaInfection in Human Airway Epithelial Cells
Authors: Zhang Zhe , Reenstra William , Weiner Daniel J. , Louboutin Jean-Pierre , Wilson James M.
Published: October 2007

In this study, we show that stimulation of human airway epithelial cells (HAECs) byPseudomonas aeruginosastrain PAO1 induces time- and dose-dependent activation of p38 mitogen-activated protein kinase (MAPK). Activated p38 MAPK stayed in the cytoplasm instead of translocating to the nucleus, as shown by cellular fractionation. p38 MAPK was activated when HAECs were incubated withP. aeruginosastrain PAK andBurkholderia cepacia, while little activation was observed with the isogenic flagellin-free strains PAK/fliCandB. cepaciaBC/fliC. The presence of Toll-like receptor 5 (TLR5) in 293 cells mediated PAO1-dependent activation of p38 MAPK, and in HAECs p38 MAPK activation was blocked by the overexpression of a dominant negative TLR5. Two inhibitors of p38 MAPK, SB202190 and SB203580, significantly attenuated PAO1-dependent expression of an NF-κB-dependent luciferase reporter gene, suggesting that p38 MAPK activation is required for full activation of NF-κB-dependent signaling. Microarray analysis of NF-κB target genes revealed up-regulation of multiple genes by PAO1 in HAECs. Reverse transcription-PCR and protein expression analysis were used to show that up-regulation of NF-κB-dependent genes induced by PAO1, such as the genes encoding Cox-2 and interleukin-8, was attenuated by SB203580. These results demonstrate a role for p38 MAPK signaling in gene regulation in response toP. aeruginosavia TLR5.
Combination of Protein and Viral Vaccines Induces Potent Cellular and Humoral Immune Responses and Enhanced Protection from Murine Malaria Challenge
Authors: Hutchings Claire L. , Birkett Ashley J. , Moore Anne C. , Hill Adrian V. S.
Published: October 2007

The search for an efficacious vaccine against malaria is ongoing, and it is now widely believed that to confer protection a vaccine must induce very strong cellular and humoral immunity concurrently. We studied the immune response in mice immunized with the recombinant viral vaccines fowlpox strain FP9 and modified virus Ankara (MVA), a protein vaccine (CV-1866), or a combination of the two; all vaccines express parts of the same preerythrocytic malaria antigen, thePlasmodium bergheicircumsporozoite protein (CSP). Mice were then challenged withP. bergheisporozoites to determine the protective efficacies of different vaccine regimens. Two immunizations with the protein vaccine CV-1866, based on the hepatitis B core antigen particle, induced strong humoral immunity to the repeat region of CSP that was weakly protective against sporozoite challenge. Prime-boost with the viral vector vaccines, FP9 followed by MVA, induced strong T-cell immunity to the CD8+epitope Pb9 and partially protected animals from challenge. Physically mixing CV-1866 with FP9 or MVA and then immunizing with the resultant combinations in a prime-boost regimen induced both cellular and humoral immunity and afforded substantially higher levels of protection (combination, 90%) than either vaccine alone (CV-1866, 12%; FP9/MVA, 37%). For diseases such as malaria in which different potent immune responses are required to protect against different stages, using combinations of partially effective vaccines may offer a more rapid route to achieving deployable levels of efficacy than individual vaccine strategies.
Agonists of Toll-Like Receptors 3, 4, 7, and 9 Are Candidates for Use as Adjuvants in an Outer Membrane Vaccine againstNeisseria meningitidisSerogroup B
Authors: Fransen Floris , Boog Claire J. , van Putten Jos P. , van der Ley Peter
Published: October 2007

The bacteriumNeisseria meningitidisis the causative agent of meningitis and sepsis. A generally effective vaccine againstN. meningitidisserogroup B is not yet available, but outer membrane vesicle vaccines are in development. These vaccines contain lipopolysaccharide (LPS). The inclusion ofN. meningitidiswild-type LPS in a vaccine is controversial because of its high toxicity. Therefore, the adjuvant activity of a panel of different Toll-like receptor (TLR) agonists in combination with LPS-deficient meningococcal outer membrane complexes was compared after immunization of mice. The results demonstrate that TLR3, TLR4, TLR7, and TLR9 agonists enhance immune responses against LPS-deficient outer membrane complexes. Their adjuvant activity was characterized by higher levels of antigen-specific immunoglobulin G (IgG), IgG2a, and IgG2b; a higher IgG2a/IgG1 ratio; lower total IgE levels; and most importantly, higher serum bactericidal antibody titers compared to LPS-deficient outer membrane complexes alone.
Chlamydia pneumoniae
Inclusion Membrane Protein Cpn0585 Interacts with Multiple Rab GTPases
Authors: Cortes Claudio , Rzomp Kimberly A. , Tvinnereim Amy , Scidmore Marci A. , Wizel Benjamin
Published: October 2007

Chlamydiae are intracellular bacteria that develop within a membrane-bound vacuole called an inclusion. To ensure that the inclusion is a safe niche for chlamydial replication, chlamydiae exploit a number of host cell processes, including membrane-trafficking pathways. Recently, several Rab GTPases were found to associate with the inclusions of various chlamydial species. Here we report that Cpn0585, a
Chlamydia pneumoniae
inclusion membrane protein (Inc), interacts with multiple Rab GTPases. The results from yeast two-hybrid experiments revealed that an amino-terminally truncated form of Cpn0585 (Cpn0585
102-651
) interacts with Rab1, Rab10, and Rab11 but not with Rab4 or Rab6. Cpn0585-Rab GTPase interactions are direct and GTP dependent as shown in glutathione
S
-transferase pull-down assays using native and recombinant Cpn0585. In
C. pneumoniae
-infected HEp-2 cells transfected with enhanced green fluorescent protein (EGFP)-tagged Rab GTPases, the colocalization with Cpn0585 at the inclusion membrane was partial for EGFP-Rab1 and EGFP-Rab10, but extensive for wild-type EGFP-Rab11A and the constitutively active GTPase-deficient EGFP-Rab11AQ70L. Moreover, Cpn0585 colocalized with EGFP-Rab11AQ70L as early as 2 h postinfection. Upon delivery into live
C. pneumoniae
-infected cells, Cpn0585
628-651
-specific antibodies bound to the inclusion membrane, demonstrating that the Rab GTPase-interacting domain of Cpn0585 faces the host cell cytosol. Finally, ectopic expression of Cpn0585
102-651
partially inhibited the development of
C. pneumoniae
inclusions in EGFP. but not in EGFP-Rab11AQ70L-expressing HEp-2 cells. Collectively, these data suggest that Cpn0585 is involved in the recruitment of Rab GTPases to the inclusion membrane and that interfering with this function may adversely impact the fitness of the
C. pneumoniae
inclusion for chlamydial replication.
Chlamydia trachomatis
Species-Specific Induction of Ezrin Tyrosine Phosphorylation Functions in Pathogen Entry
Authors: Swanson Kena A. , Crane Deborah D. , Caldwell Harlan D.
Published: October 2007

Chlamydia trachomatis
is an obligate intracellular pathogen of humans that exhibits species-specific biological characteristics in its early interactions with host cells that are likely important to pathogenesis. One such characteristic is the tyrosine phosphorylation (Tyr-P) of an ∼70-kDa polypeptide that occurs only after infection of mammalian cells by human strains. We sought to identify this protein because of its potential significance to the pathogenesis of human chlamydial infections. Using an immunoproteomic approach we identified the host protein ezrin, a member of the ezrin-radixin-moesin (ERM) protein family that serves as a physical link between host cell receptors and the actin cytoskeleton. Confocal microscopy studies showed colocalization of ezrin and actin at the tips and crypts of microvilli, the site of chlamydial attachment and entry, respectively. To demonstrate a functional role for ezrin we infected cells with a dominant-negative (DN) ezrin phenotype or treated cells with ezrin-specific small interfering RNA (siRNA). We found that both DN and siRNA-treated cells were significantly less susceptible to infection by human chlamydial strains. Moreover, we demonstrated that inhibition of infection in ezrin DN cells occurred at the stage of chlamydial entry. We hypothesize that the
C. trachomatis
-specific Tyr-P of ezrin might relate to an undefined species-specific mechanism of pathogen entry that involves chlamydial specific ligand(s) and host cell coreceptor usage.
Taxonomy of Daedaleopsis flavida comb. nov.
Authors: Roy Anjali , Mitra A.
Published: October 2007

Morphological and cultural characters of Daedaleopsis flavida (Lév.) Roy & Mitra comb. nov. have been studied and as a result the taxonomy of the fungus is discussed.
The genus Gracilaria (Rhodophyta, Gigartinales) in the western Atlantic. Gracilaria domingensis, G. cervicornis, and G. ferox
Authors: Oliveira E. C. De , Bird C. J. , McLachlan J.
Published: October 2007

Three frequently confused species of Gracilaria Greville, G. domingensis Sond. Ex Kütz., pro syn., G. cervicornis (Turn.) J. Ag., and G. ferox J. Ag. have been reassessed. Gracilaria domingensis, despite morphological similarity to the other two species, is clearly distinct by virtue of having spermatangia in deep crypts and a thin cortex of subquadrate cells. Not only do G. cervicornis and G. ferox share the characteristics of spermatangia in shallow conceptacles and a multilayered cortex of radially elongated cells but they are anatomically indistinguishable and have identical distributions in the western Atlantic. This plus the range of morphologies intermediate between the typical forms support a reduction of this complex to a single species, G. cervicornis. The presence of small interstitial cells in the medulla of these plants is documented, and detailed descriptions of the species are provided.
The ecology of Rhizocarpon superficielle. I. The rock surface boundary-layer microclimate
Authors: Coxson D. S. , Kershaw K. A.
Published: October 2007

The thermal environment of the crustaceous lichen Rhizocarpon superficiale (Schaer.) Vain, is documented for spring and summer conditions using selected data characteristic of a range of thallus hydration conditions. During extended rainfall periods hydrated thallus temperatures largely parallel air temperature, usually remaining below 10 °C. However, quite often periods of shower activity alternate rapidly with intervals of full solar isolation, particularly during summer thundershower activity. This can result in hydrated thallus temperatures, fluctuating from 5 to 20 °C within minutes. An equally wide range of hydrated thallus temperatures is also evident under spring snowmelt conditions. Under the high levels of convective cooling typical of the exposed habitat of Rhizocarpon superficiale, thallus temperatures under maximum solar radiation conditions in midsummer rarely rise above 32 °C. Under still conditions thallus temperatures rapidly reach a potentially stressful level of 45 °C and it is probable that strong convective cooling in summer plays an important role in the ecology of R. superficiale.
Évolution comparée de l'amidon et des glucides éthanolo-solubles dans les tumeurs produites par Eriosoma lanigerum sur Pirus malus cultivar 'Calville blanc' et dans les rameaux sains témoins
Authors: Jeanneau Yves , Quemener Bernard
Published: October 2007

In the tumors caused by Eriosoma lanigerum Haussm. on Pirus malus L. cultivar 'Calville blanc,' the starch disappears gradually and according to a determined order, first in the pathological tissues, then in the underlying healthy ones. This depletion depends on the action of an amylase which is contained in the insect's saliva. Tumoral cells of the xylem never contain starch. The infected shoots are more turgescent than the healthy ones. The amount of mannose is higher in the tumors than in the healthy shoots. It appreciably increases with the growth of tumoral tissues. This increase may be linked to the phenomenon of delignification of the ligneous tissues, in particular the xylem. The tumors also contain some glucose, some raffinose, lactose, maltose, and more saccharose than the healthy shoots.
Craterellus humphreyi, an unusual Stereopsis from western North America
Authors: Redhead S. A. , Reid D. A.
Published: October 2007

Craterellus humphreyi Burt, a rare species with white, nutant, dimidiate pilei, is transferred to the genus Stereopsis. The species is endemic to western North America where it occurs in wet depressions in coniferous forests.
Spore morphology and taxonomy of Isoetes in northeastern North America
Authors: Kott L. , Britton D. M.
Published: October 2007

Taxonomy of Isoetes L. largely rests on megaspore and microspore wall ornamentation and spore size. These characters have been reevaluated and the range of their variability is described (SEM photographs). Eight species of Isoetes are recognized for northeastern North America: I. macrospora, I. hieroglyphica, I. tuckermanii, I. riparia, I. acadiensis, I. echinospora, I. eatonii, and I. engelmannii. Each species is provided with a revised list of synonyms, description, ecological notes, representative specimens, and distribution maps. A key to species is provided.
Chestnut blight and recovering American chestnut trees in Michigan
Authors: Fulbright D. W. , Weidlich W. H. , Haufler K. Z. , Thomas C. S. , Paul C. P.
Published: October 2007

Stands of American chestnut trees have survived in Michigan in spite of the presence of Endothia parasitica. Cankered trees were evaluated in eight groves in seven of which two types of abnormal cankers were observed. These abnormal cankers resulted when diseased periderm was replaced by wound periderm. Endothia parasitica isolated from abnormal cankers often differed from E. parasitica isolated from normal cankers in that the isolates had abnormal culture morphology, reduced virulence, and contained double-stranded ribonucleic acid (dsRNA). These characteristics are similar to those of hypovirulent strains of E. parasitica found in Europe, except that four different dsRNA banding patterns were found in Michigan isolates, indicating different dsRNA genomes. Pathogenicity tests showed that host resistance or tolerance probably is not responsible for the prolonged life of infected trees in certain groves. Therefore, native Michigan hypovirulent isolates of E. parasitica may be responsible for the recovering American chestnut groves in Michigan.
Late-glacial and postglacial vegetation history at Bear Cove Bog, northeast Vancouver Island, British Columbia
Authors: Hebda Richard J.
Published: October 2007

At 13 630 ± 310 BP (WAT-721) Port Hardy is the earliest area known to have been deglaciated at the end of the Fraser Glaciation on Vancouver Island. Pollen and macrofossil analyses of two cores from a basin–blanket bog show that about 14 000 years ago Pinus contorta, Alnus, and Pteridium aquilinum formed pioneering vegetation typical of post-ice environments on the Pacific Northwest coast. Climate is interpreted to have been relatively cool and dry. Picea sitchensis – Tsuga mertensiana forest succeeded at about 11 500 BP and persisted until about 10 000 BP. Climate was cool, moist, and maritime. Warming at about 10 000 BP permitted Tsuga heterophylla gradually to replace T. mertensiana. At 8800 BP Pseudotsuga menziesii migrated into the area and together with P. sitchensis dominated the forest. Abundant Pteridium aquilinum spores suggest forests were open. During the interval 8800 to 7000 BP the climate was warmer and drier than at present because today forests with Pseudotsuga do not extend as far north as Port Hardy. During this warm time, shallow ponds dried out. By 7000 BP Pseudotsuga declined and T. heterophylla and P. sitchensis dominated forests. Climate became wetter and cooler than in the preceding period but not as cool as today. About 3000 BP Cupressaceae, presumably both Thuja plicata and Chamaecyparis nootkatensis, shared the forest canopy with T. heterophylla. Sphagnum growth and bog development occurred after 7000 BP as climate became moister. The vegetation sequence described is a "maritime" type similar to sequences on the west coast of Washington State but unlike those from the Fraser Lowland. The xerothermic interval was of short duration between 8800 and 7000 BP but was expressed clearly in this area of moist maritime climate and therefore must have been of considerable amplitude. Vegetation differences between coastal and inland southwestern British Columbia were established by 11 500 BP.
Effects of leaf age, leaf area, and other factors on tuberization of cuttings from induced potato (Solanum tuberosum) shoots
Authors: Kahn Brian A. , Ewing Elmer E. , Senesac Anne H.
Published: October 2007

Potato plants (Solanum tuberosum L. cultivars 'Belchip,' 'Chippewa,' 'Katahdin,' and 'Norchip') were grown in a glasshouse under continuous light. Thereafter, various photoperiodic treatments were given to these plants and cuttings were taken from the shoots. Different excision treatments were applied to the cuttings, which were then placed in a mist bench under continuous light and examined for tuberization after 12 days. Young, fully expanded leaves were most effective in supporting tuberization of cuttings from induced plants; but even very young or very old leaves increased tuberization. In proportion to growth at aerial buds, there was often more tuberization from a small leaf area consisting of young, expanding and fully expanded leaves than from a large area of older, more senescent leaves. The shoot apex also contributed to tuberization of induced cuttings. Induction to tuberize led to a shift from aerial bud growth to underground bud growth. For a given leaf age, partitioning of dry matter to underground buds rather than to aerial buds was decreased by reducing the leaf area and increased by increasing the level of induction.
Seed dispersal and dormancy patterns in northern willows: ecological and evolutionary significance
Authors: Densmore Roseann , Zasada John
Published: October 2007

Seeds of the 24 common Salix species of the Alaskan boreal forest and tundra were set to germinate in laboratory and field experiments, and seed dispersal times were observed. During the growing season, 16 species disperse short-lived, nondormant seeds. At the end of the growing season, eight other species, all tundra willows, disperse conditionally dormant seeds. These fall-dispersed seeds are fully developed in the same length of time as summer-dispersed seeds, but they develop dormancy while being held on the plant until the leaves senesce. At the time of dispersal, some seeds are capable of germinating at high temperatures, but no seeds can germinate at the low soil temperatures occurring then. Cold stratification gradually widens the range of temperatures at which seeds can germinate, and seeds germinate at low soil temperatures in the spring shortly after snowmelt. Salix species dispersing dormant seeds during the fall appear to have evolved, as an adaptation to short growing seasons in cold climates, from taxa dispersing nondormant seeds during the summer.
Maximally informative hierarchy construction by successive two-state classification
Authors: Baum Bernard R. , Estabrook George F.
Published: October 2007

Concepts for what it means for a classification to preserve information about taxonomic characters have been defined by various authors. Here we generalize with a single continuous parameter some of these concepts, and for a natural example comprising the characters and species of the genus Avena (Poaceae), compute by exhaustive search those classifications that most efficiently preserve information in the characters for several parameter values. Although these classifications are quite reasonable, it seems clear that the preservation of information is not the only desirable criterion for structuring classifications in botany. The work is preliminary in the sense that readers are invited to consider what might be the most useful range of parameter values.
Genetics of Gibberella fujikuroi. III. Significance of heterokaryosis in naturally occurring corn isolates
Authors: Sidhu Gurmel S.
Published: October 2007

Among the stalk rot fungal organisms, Gibberella fujikuroi (Saw.) Wn. (conidial anamorph Fusarium moniliforme Sheld.) was abundant in naturally infected com plants. Numerous phenotypically different isolates of F. moniliforme were recovered from the host. Some of these isolates formed heterokaryons more frequently in a given stage of plant growth. Frequently occurring heterokaryons were termed major and became the subject of this report. The component homokaryons exhibited differences in colony color, texture, growth rate, and sporulation. Based on these differences, ratios of two homokaryons recovered from a single representative of each of the four major heterokaryons were found to be balanced. Representative natural and laboratory-induced heterokaryons were compared for stability and balance of nuclear ratios on MM and SRM (stalk residue medium). Different heterokaryons predominated at different growth stages of the corn plant indicating preferential adaptation. Possible role of these heterokaryons in generating and maintaining natural variability was evaluated.
Seasonal changes in the germination responses of seeds of Veronica peregrina during burial, and ecological implications
Authors: Baskin Jerry M. , Baskin Carol C.
Published: October 2007

Seeds of Veronica peregrina collected from a field population in central Kentucky were buried in soil and exposed to seasonal temperature changes. Fresh seeds and those exhumed after 1–26 months were tested in light and darkness at five thermoperiods simulating those in the natural habitat from early spring through late autumn. Freshly matured seeds were dormant, but they came out of dormancy in June and July and germinated to 98–100% in light in August at thermoperiods of 20:10, 25:15, 30:15, and 35:20 °C. Seeds retained the ability to germinate to high percentages at these temperatures until late winter and spring, but they never germinated to high percentages in darkness. Thus, in the natural habitat in July and August germination is prevented only by darkness and (or) insufficient soil moisture. At simulated habitat temperatures, seeds germinated to 88–100% in March and April but to only 21–69% in May and June. Seeds incubated at 15:6 °C showed a decline in germination percentages in late summer and autumn and an increase during late autumn and winter. The same general pattern of seasonal changes in germination response to temperature occurred during the 2nd year of burial.
Adenosine triphosphate and adenylate energy charge in relation to dormancy of wild oat seeds
Authors: Adkins Stephen W. , Ross James D.
Published: October 2007

Adenosine phosphates, expressed as ATP and energy charge levels, were compared in genetically identical dormant and nondormant caryopses of wild oat (Avena fatua L.). Air-dry nondormant caryopses had a larger pool of ATP and a higher energy charge than dormant caryopses. During the early hours of imbibition of water by dormant caryopses, ATP levels and energy charge increased indicating they are not limiting factors for germination. Moreover, during the induction of germination in dormant caryopses by gibberellic acid (GA3), changes in energy charge were similar to those observed on water, indicating that GA3 does not overcome dormancy simply by elevating energy charge levels. In a second study, ATP and energy charge were measured in initially dormant caryopses incubated under conditions of temperature that either removed or retained dormancy. Both embryo and endosperm extracts demonstrated correlations between levels of ATP or energy charge with temperature of incubation but not with the state of dormancy. The conclusions drawn from both lines of investigation do not support the hypothesis that release of dormancy is related to the metabolism of adenosine phosphates in caryopses of wild oat.
Floraison et réversion chez Sinapis alba. III. Effets immédiats et différés de divers régimes d'éclairement appliqués pendant la phase post-inductrice
Authors: Bagnard Clémence
Published: October 2007

Transferring induced plants to a dysperiod, under different light intensities, brings in apical organs the following disruptions: (i) a general slowing down (braking), all the more since light intensity is lower, of organogenetic activity in the apical meristem of the main inflorescence, and propagation of reproductive functioning to apical meristems of the subjacent lateral buds; (ii) some arrests in floral development, which allow the definition of two critical stages, corresponding respectively with initiation of floral parts and their final growth; (iii) a change in correlations between the apical meristem of the main inflorescence and subjacent lateral formations: flowers and young lateral axes. Apparently, competitive relationships are set up which lead in some cases to the death of young flowers and even of the apical meristem. In more severe conditions, the development of floral buds remains below the first critical stage and the apical meristem becomes dominant. When plants are returned to inductive conditions, these buds which were blocked for a long time develop into leaf–branch couples, making up an inflorescence reversion. The possible links between pollen degeneration and the second critical stage, and between leaf growth and the end of "crisis" during the braking phase, are considered. The use of different parameters for a quantitative evaluation of reversion is discussed.
Histopathology of Verticillium dahliae within mature roots of Russet Burbank potatoes
Authors: Perry James W. , Evert Ray. F.
Published: October 2007

Roots of Russet Burbank potatoes (Solanum tuberosum L.) inoculated with Verticillium dahliae Kleb. were examined, primarily with the electron microscope. Penetration hyphae entered epidermal cells directly, apparently aided by hydrolytic enzymes. In most instances, penetration took place without eliciting any structural response. Most hyphae failed to penetrate deeper than the epidermal layer, owing primarily to the formation by exodermal cells of lignitubers that ensheathed the penetration hyphae. Apparently lignitubers were sometimes initiated as callose-like appositions opposite encounter sites. All cortical layers were capable of lignituber production. Few hyphae were encountered within cells deeper than the second cortical layer, and intercellular colonization was not extensive. Nonetheless, vascular infection of unwounded roots occurred. Wilt symptoms were first noted 2 days after hyphae were found in vessel elements of the root. Walls and pit membranes of colonized tracheary elements were coated with an electron-dense substance. As the disease progressed, hyphae invaded all tissues in the vascular cylinder and eventually grew back out into the cortex. The soft-walled tissues were destroyed. In wounded roots many severed vessels contained membranous remnants, conidia, and hyphae that tended to be accumulated at the perforation plates.
Influence de l'interaction genome–cytoplasme sur la formation de fleurs in vivo et in vitro chez les hybrides entre Nicotiana plumbaginifolia et Nicotiana tabacum
Authors: Hanh Trinh T. , Van K. Tran Thanh
Published: October 2007

In well-defined conditions (temperature, light, culture medium), the morphology of flowers formed in vivo and the type of flowers formed in vitro (direct flowers or flowers developed after the formation of some leaves) depend on the dominant proportion of nuclear genome of one of the two parental species. Moreover, the coexistence of Nicotiana tabacum genome with Nicotiana plumbaginifolia cytoplasm brings about the differentiation of exposed ovules on stigmatoid anthers.
Régulation de l'activité de la nitrate réductase dans une suspension cellulaire de Silene alba
Authors: Rambour Serge , Poulle Michel , Daniau Jean-Luc , Brassart Colette
Published: October 2007

not available
Les Bruyères in vitro. I. Culture in vitro de l’Erica × darleyensis et mise en évidence d'une croissance rythmique accentuée des rameaux orthotropes
Authors: Beaujard François , Astié Monique
Published: October 2007

not available
Étude du polymorphisme intraclonal chez le Verticillium albo-atrum, forme à microsclérotes. IV. L'aptitude à varier chez les variants morphologiques
Authors: Boisson Claude , Lahlou Houria
Published: October 2007

The capacity for variation was studied using 10- to 18-month-old cultures of the main variants of two Moroccan isolates of Verticillium albo-atrum R. et B. (microsclerotial form). The hyaline variants were very stable and never returned to the wild type. The other variants gave rise to new variants which differed even more from the wild type but never reverted. A "mixed" type of variant, hyaline but with patches or sectors resembling the wild type, gave rise to wild or hyaline cultures when subcultured, depending on the conditions of transfer. All other variation tended toward a stronger alteration of sclerogenesis without reversing and an irreversible loss of ability to produce microsclerotia (hyaline cultures).
Burl sprouting in Arctostaphylos uva-ursi as a response to trampling damage
Authors: Bowles Jane M.
Published: October 2007

Plants of Arctostaphylos uva-ursi (L.) Spreng. were damaged by an experimental human trampling treatment in August 1979. In October of the same year sprouting from lateral buds and burls was observed respectively on upright and trailing stems damaged by trampling. The phenology of spring sprouting was advanced in damaged plants compared with undamaged plants the following year
Epizoic occurrence of Compsopogon coeruleus (Rhodophyta) on Lernaea (Copepoda) from Kentucky fishes
Authors: Camburn Keith E. , Warren Jr. Melvin L.
Published: October 2007

The freshwater red alga Compsopogon coeruleus (Balbis) Montagne occurred epizoically on the parasitic copepod genus Lernaea from fishes (Osteichthyes, Cyprinidae) collected from the Mud River, Butler County, Kentucky. Twelve specimens of Lernaea spp. (12.3% of the total number examined) taken from five fish species supported growth of C. coeruleus. This alga has not been previously reported from an epizoic habitat.