bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Root and Crown Necrosis of Bean Caused by Pythium aphanidermatum in Spain
Authors: Serrano Y. , Guirado M. L. , Carmona M. P. , Gómez J. , Melero-Vara J. M. 
Published: December 2007

Adult bean plants (Phaseolus vulgaris cv. Festival) growing in a commercial greenhouse in southeastern Spain developed symptoms of root necrosis, necrotic streaks on the basal stems, and plant wilt. A Pythium sp. was isolated consistently from roots and basal stems on selective agar (P5ARP). Single-hyphal transfers produced intercalary antheridia, oogonia (23 to 26 μm in diameter), oospores (18 to 20 μm in diameter), and zoospores in toruloid sporangia. Cardinal temperatures were a minimum of 10°C, an optimum of 28 to 34°C, and a maximum of 40°C. Daily growth rate on corn meal agar at 25°C was 15 mm. The internal transcribed spacer 1 (ITS 1) rDNA sequence of the isolate matched the sequences of Pythium aphanidermatum in GenBank. The sequence of isolate Py-294 was deposited in GenBank, Accession No. AM396563. This isolate was identified as P. aphanidermatum on the basis of morphological and cultural characteristics (1) and the ITS rDNA sequence. To fulfill Koch's postulates, 50 ml of inoculum of isolate Py-294 was used to inoculate bean plants (cvs. Donna and Emerite) at the five-leaf stage. The inoculum was prepared by homogenizing 2-week-old potato dextrose agar-petri plate cultures in 300 ml of distilled water. The plants were maintained in a greenhouse at temperatures of 18.8 to 30.3°C. Irrigation water had an electric conductivity of 0.5 to 0.6 dS·m–1 while the nutrient solution had 1.9 to 2.1 dS·m–1. Two months after sowing, 35.4 and 100% of cvs. Donna and Emerite, respectively, developed root necrosis, while control plants grown in bags containing noninoculated perlite remained healthy. The pathogen was reisolated from roots and basal stems of symptomatic plants. The test was repeated with similar results. To our knowledge, this is the first report of P. aphanidermatum as the causal agent of root and crown necrosis of adult bean plants in Spain. Reference: (1) A. J. Van der Plaats-Niterink. Stud. Mycol. 21:242, 1981.
First Report of Xylella fastidiosa in Avocado in Costa Rica
Authors: Montero-Astúa M. , Saborío-R. G. , Chacón-Díaz C. , Garita L. , Villalobos W. , Moreira L. , Hartung J. S. , Rivera C. 
Published: December 2007

Since the late 1990s, chlorotic mottling, marginal scorch, deformation of leaves, defoliation, shortening of internodes, and branch dieback have been observed in avocado trees (Persea americana Mill.) in Costa Rica. The symptoms are not uniformly distributed in the tree, so some branches are symptomatic while others are not. These symptoms are similar to several leaf scorch diseases caused by the bacterium Xylella fastidiosa Wells (2,4). This bacterium has been detected in coffee and citrus plants in Costa Rica. Of 227 avocado trees tested by double-antibody sandwich (DAS)-ELISA with X. fastidiosa specific antiserum (Agdia Inc., Elkhart, IN) from 2000–2004, 188 were positive. Results of ELISA tests of individual trees varied with the season and branches tested. Fifteen greenhouse-grown, ELISA-negative avocado seedlings were grafted with budwood from an ELISA-positive tree. Eight of these developed scorch symptoms and one also showed chlorotic mottling and deformation, showing that the disease is graft transmitted. All of these features are characteristic of diseases caused by X. fastidiosa (2,4). Transmission electron microscopy of leaf petioles from three field trees positive by ELISA, revealed rod-shaped bacilli approximately 1.6 to 2.0 μm long and 0.3 μm in diameter with a rippled cell wall inside xylem vessels and embedded in a matrix; morphology and measurements that are consistent with those reported for X. fastidiosa (2). DNA extraction and PCR attempts have been limited by mucilaginous sap from avocado. Positive PCR results (approximately 472-bp band) were obtained from two of the grafted seedlings and seven field trees from two distinct geographical locations (Alajuela and San José provinces) with DNA extractions from the plant sap using DNeasy Plant Mini Kit (Qiagen GmbH, Hilden, Germany) following a modified protocol (1) and nested PCR (3). Four of the PCR products, including one from the grafted seedlings, were cloned and sequenced in duplicate. GenBank sequences EU021997 to EU022000 present 99 to 100% sequence identity to a Pierce's disease strain from California (Temecula1) and 94 to 95% to a citrus variegated chlorosis strain from Brazil (Found-5). Several attempts have been made to isolate the bacterium in ‘periwinkle wilt’ and buffered cysteine-yeast extract media with negative results, probably because of the rapid production of mucilaginous sap when the avocado tissues were sampled. To our knowledge, this is the first report of X. fastidiosa in avocado trees. References: (1) M. J. Green et al. Plant Dis. 83:482, 1999. (2) S. S. Hearon et al. Can. J. Bot. 58:1986, 1980. (3) M. R. Pooler and J. S. Hartung. Curr. Microbiol. 31:377, 1995. (4) A. H. Purcell et al. Phytopathology 89:53, 1999.
First Report of Pestalotiopsis dyospiri Causing Calyx Blight of Sweet Persimmon in Huelva Province (Southwestern Spain)
Authors: Blanco C. , Romero F. , De los Santos B. 
Published: December 2007

In November 2006, necrotic calyxes were observed in more than 90% of harvested sweet persimmon fruits (Diospyros kaki L. fil.), cv. Triumph, in orchards located in Huelva Province. Symptoms appeared on sepals as brown-to-black necrotic areas; one to four sepals per fruit could be affected. Necrotic sepal tissues were surface disinfected and placed on potato dextrose agar medium (PDA). A fungus was consistently isolated from affected tissue on 60% of fruits sampled. Isolates formed acervular conidiomata (75.7 ± 4.69 μm in diameter) with fusiform conidia that were straight or rarely curved. Conidia were five celled, including three umbercolored medial cells and hyaline apical and basal cells. All conidia possessed two to three apical appendages and a single basal one. Conidia (N = 60) were 17.03 ± 0.25 μm long × 4.55 ± 0.1 μm wide; the three medial cells were 11.78 ± 0.15 μm long and apical cells were 2.34 ± 0.11 μm, with apical appendages measuring 12.45 ± 0.36 μm. Basal cells were 2.98 ± 0.11 μm and basal appendages were 3.93 ± 0.14 μm long. On the basis of these characteristics, the causal agent was identified as Pestalotiopsis diospyri Sidow et P. Sidow (2), that was previously described as a persimmon pathogen on leaves in Japan (3). To confirm pathogenicity, calyxes of healthy unwounded fruits were sprayed with 3 ml of a conidia suspension (1.5 × 105 conidia per ml) and maintained in moist chambers at 24°C for 10 days. All fruits presented necrotic calyxes, and the pathogen was reisolated from affected tissue in 100% of the samples. P. diospyri has been reported to be present on calyxes of unhealthy persimmon fruits in different productive regions in New Zealand (1), but to our knowledge, this is the first time that pathogenicity of this fungus was demonstrated on sweet persimmon fruits in Spain. References: (1) H. H. Goh et al. Proc N Z Weed Pest Control Conf. 44:265, 1991. (2) E. F. Guba. Page 184 in: Monograph on Monochaetia and Pestalotia. Harvard University Press, Cambridge, MA. 1961. (3) F. Yasuda et al. J. Gen. Plant Pathol. 69:29, 2003.
First Outbreak of Bacterial Black Rot on Cabbage, Broccoli, and Brussels Sprouts Caused by Xanthomonas campestris pv. campestris in the Mediterranean Region of Turkey
Authors: Mirik M. , Selcuk F. , Aysan Y. , Sahin F. 
Published: December 2007

During warm and humid periods in the winters of 2004 to 2006, severe leaf necrosis and vein rot symptoms were observed on cabbage (Brassica oleracea var. capitata L.), broccoli (Brassica oleracea var. italica Plenck.), and Brussels sprouts (Brassica oleracea var. gemmifera D.C.) in the Mediterranean Region of Turkey. Symptoms were characterized by yellow, V-shaped areas of the leaf margin, with the internal tissue turning from brown to black. Infected seedlings were also observed in commercial nurseries in Adana with a disease incidence of nearly 10 to 25%. Isolations made from leaves and veins of the affected plants on yeast dextrose calcium carbonate agar yielded yellow, mucoid, and convex colonies. Twenty isolates recovered from diseased leaf samples were selected at random to identify the causal organism. All isolates were nonspore forming, gram negative, rod shaped, motile, aerobic, oxidase-negative, catalase-positive, and amylolytic-positive (3). All isolates induced hypersensitive responses on tobacco (Nicotiana tabacum cv. Samsun). The isolates were identified as Xanthomonas campestris pv. campestris on the basis of fatty acid methyl ester (FAME) profiles determined by Sherlock Microbial Identification System software (Microbial ID, Newark, DE) and indirect ELISA. The similarity indices for the FAME analysis ranged from 80 to 94% (2). Indirect ELISA with a polyclonal antibody (Agdia, Elkhart IN; BRA 97000/0500) further confirmed the identity of the pathogen in both pure culture and infected plant. The mean absorbance values for three replications of indirect ELISA tests ranged from 1.411 to 3.508 at a wavelength of A405 (1). Pathogenicity of the isolates was tested on 5-week-old cabbage plants by spray inoculation using bacterial suspensions (107 CFU/ml) prepared in saline buffer (0.85% NaCl). Sterile saline buffer was sprayed on negative control plants. Inoculated and control plants were maintained for 5 days at 25°C and 70% relative humidity to observe symptom development. No symptoms developed on negative control plants. The bacterium was reisolated from inoculated cabbage plants and identified as X. campestris pv. campestris by FAME and an ELISA test. To our knowledge, this is the first report of the occurrence and outbreak of X. campestris pv. campestris in the Mediterranean Region of Turkey. References: (1) A. M. Alvarez et al. Phytopathology 84:1449, 1994. (2) A. R. Chase et al. Phytopathology 82:754, 1992. (3) N. W Schaad et al. Xanthomonas. Page 175 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. American Phytopathological Society. St. Paul, MN, 2001.
Replication of Colonic Crohn's Disease Mucosal
Escherichia coli
Isolates within Macrophages and Their Susceptibility to Antibiotics
Authors: Subramanian Sreedhar , Roberts Carol L. , Hart C. Anthony , Martin Helen M. , Edwards Steve W. , Rhodes Jonathan M. , Campbell Barry J. 
Published: December 2007

ABSTRACT

There is increasing evidence that
Escherichia coli
organisms are important in Crohn's disease (CD) pathogenesis. In CD tissue they are found within macrophages, and the adherent-invasive CD ileal
E. coli
isolate LF82 can replicate inside macrophage phagolysosomes. This study investigates replication and antibiotic susceptibility of CD colonic
E. coli
isolates inside macrophages. Replication of CD colonic
E. coli
within J774-A1 murine macrophages and human monocyte-derived macrophages (HMDM) was assessed by culture and lysis after gentamicin killing of noninternalized bacteria and verified by electron microscopy (EM). All seven CD colonic isolates tested replicated within J774-A1 macrophages by 3 h (6.36-fold ± 0.7-fold increase;
n
= 7 isolates) to a similar extent to CD ileal
E. coli
LF82 (6.8-fold ± 0.8-fold) but significantly more than control patient isolates (5.2-fold ± 0.25-fold;
n
= 6;
P
= 0.006) and
E. coli
K-12 (1.0-fold ± 0.1-fold;
P
< 0.0001). Replication of CD
E. coli
HM605 within HMDM (3.9-fold ± 0.7-fold) exceeded that for K-12 (1.4-fold ± 0.2-fold;
P
= 0.03). EM showed replicating
E. coli
within macrophage vacuoles. Killing of HM605 within J774-A1 macrophages following a 3-h incubation with antibiotics at published peak serum concentrations (
C
max
) was as follows: for ciprofloxacin, 99.5% ± 0.2%; rifampin, 85.1% ± 6.6%; tetracycline, 62.8% ± 6.1%; clarithromycin, 62.1% ± 5.6% (all
P
< 0.0001); sulfamethoxazole, 61.3% ± 7.0% (
P
= 0.0007); trimethoprim, 56.3% ± 3.4% (
P
< 0.0001); and azithromycin, 41.0% ± 10.5% (
P
= 0.03). Ampicillin was not effective against intracellular
E. coli
. Triple antibiotic combinations were assessed at 10%
C
max
, with ciprofloxacin, tetracycline, and trimethoprim causing 97% ± 0.0% killing versus 86% ± 2.0% for ciprofloxacin alone. Colonic mucosa-associated
E. coli
, particularly CD isolates, replicate within macrophages. Clinical trials are indicated to assess the efficacy of a combination antibiotic therapy targeting intramacrophage
E. coli
.
Staphylococcus aureus
Clinical Isolate with High-Level Methicillin Resistance with an
lytH
Mutation Caused by IS
1182
Insertion
Authors: Fujimura Takaji , Murakami Kazuhisa 
Published: December 2007

ABSTRACT

We previously reported that deficiency of the
lytH
gene, whose product is homologous to lytic enzymes, caused the elevation of methicillin resistance in
Staphylococcus aureus
strain SR17238, a strain of
S. aureus
with a low level of resistance to methicillin (low-level MRSA) (J. Bacteriol. 179:6294-6301, 1997). In this study, we demonstrated that deficiency of
lytH
caused the same phenomenon in four other clinical isolates of low-level MRSA, suggesting this deficiency to exist in clinical isolates. We therefore searched the region including
lytH
in 127 clinical isolates of MRSA by PCR and found one strain, SR17164 (methicillin MIC, 1,600 μg/ml), in which the
lytH
gene was inactivated by insertion sequence IS
1182. lytH
::IS
1182
was replaced with intact
lytH
in this strain by integration and excision of the plasmid carrying the
lytH
region. Recombinants with intact
lytH
genes showed methicillin MICs of 800 μg/ml, twofold lower than those of the recombinants with
lytH
::IS
1182
and the parent. In addition,
S. aureus
SR17164, which has a high level of methicillin resistance, had properties similar to those caused by
lytH
deficiency; that is, the resistance levels of strain SR17164 and
lytH
-deficient variants from strain SR17238 were not significantly affected by
llm
inactivation, which greatly lowered resistance levels in most other high-level MRSA strains. These findings suggest that
lytH
inactivation contributed, to some extent, to the resistance level of
S. aureus
SR17164. To the best of our knowledge, this strain is the first clinical isolate of MRSA for which the genetic base for high-level resistance has been clarified.
Biosynthetic Investigations of Lactonamycin and Lactonamycin Z: Cloning of the Biosynthetic Gene Clusters and Discovery of an Unusual Starter Unit
Authors: Zhang Xiujun , Alemany Lawrence B. , Fiedler Hans-Peter , Goodfellow Michael , Parry Ronald J. 
Published: December 2007

ABSTRACT

The antibiotics lactonamycin and lactonamycin Z provide attractive leads for antibacterial drug development. Both antibiotics contain a novel aglycone core called lactonamycinone. To gain insight into lactonamycinone biosynthesis, cloning and precursor incorporation experiments were undertaken. The lactonamycin gene cluster was initially cloned from
Streptomyces rishiriensis
. Sequencing of ca. 61 kb of
S. rishiriensis
DNA revealed the presence of 57 open reading frames. These included genes coding for the biosynthesis of
l
-rhodinose, the sugar found in lactonamycin, and genes similar to those in the tetracenomycin biosynthetic gene cluster. Since lactonamycin production by
S. rishiriensis
could not be sustained, additional proof for the identity of the
S. rishiriensis
cluster was obtained by cloning the lactonamycin Z gene cluster from
Streptomyces sanglieri
. Partial sequencing of the
S. sanglieri
cluster revealed 15 genes that exhibited a very high degree of similarity to genes within the lactonamycin cluster, as well as an identical organization. Double-crossover disruption of one gene in the
S. sanglieri
cluster abolished lactonamycin Z production, and production was restored by complementation. These results confirm the identity of the genetic locus cloned from
S. sanglieri
and indicate that the highly similar locus in
S. rishiriensis
encodes lactonamycin biosynthetic genes. Precursor incorporation experiments with
S. sanglieri
revealed that lactonamycinone is biosynthesized in an unusual manner whereby glycine or a glycine derivative serves as a starter unit that is extended by nine acetate units. Analysis of the gene clusters and of the precursor incorporation data suggested a hypothetical scheme for lactonamycinone biosynthesis.
In Vitro Resistance Study of AG-021541, a Novel Nonnucleoside Inhibitor of the Hepatitis C Virus RNA-Dependent RNA Polymerase
Authors: Shi Stephanie T. , Herlihy Koleen J. , Graham Joanne P. , Fuhrman Shella A. , Doan Chau , Parge Hans , Hickey Michael , Gao Jingjin , Yu Xiu , Chau Fannie , Gonzalez Javier , Li Hui , Lewis Cristina , Patick Amy K. , Duggal Rohit 
Published: December 2007

ABSTRACT
A novel class of nonnucleoside hepatitis C virus (HCV) polymerase inhibitors characterized by a dihydropyrone core was identified by high-throughput screening. Crystallographic studies of these compounds in complex with the polymerase identified an allosteric binding site close to the junction of the thumb and finger domains, approximately 30 Å away from the catalytic center. AG-021541, a representative compound from this series, displayed measurable in vitro antiviral activity against the HCV genotype 1b subgenomic replicon with a mean 50% effective concentration of 2.9 μM. To identify mutations conferring in vitro resistance to AG-021541, resistance selection was carried out using HCV replicon cells either by serial passages in increasing concentrations of AG-021541 or by direct colony formation at fixed concentrations of the compound. We identified several amino acid substitutions in the AG-021541-binding region of the polymerase, including M423(T/V/I), M426T, I482(S/T), and V494A, with M423T as the predominant change observed. These mutants conferred various levels of resistance to AG-021541 and structurally related compounds but remained sensitive to interferon and HCV polymerase inhibitors known to interact with the active site or other allosteric sites of the protein. In addition, dihydropyrone polymerase inhibitors retained activity against replicons that contain signature resistance changes to other polymerase inhibitors, including S282T, C316N, M414T, and P495(S/L), indicating their potential to be used in combination therapies with these polymerase inhibitors. AG-021541-resistant replicon cell lines provide a valuable tool for mechanism-of-action studies of dihydropyrone polymerase inhibitors. The clinical relevance of in vitro resistance to HCV polymerase inhibitors remains to be investigated.
Deactivation of Human Immunodeficiency Virus Type 1 in Medium by Copper Oxide-Containing Filters
Authors: Borkow Gadi , Lara Humberto H. , Covington Chandice Y. , Nyamathi Adeline , Gabbay Jeffrey 
Published: December 2007

ABSTRACT
Human immunodeficiency virus type 1 (HIV-1) can be transmitted through breast-feeding and through contaminated blood donations. Copper has potent biocidal properties and has been found to inactivate HIV-1 infectivity. The objective of this study was to determine the capacity of copper-based filters to inactivate HIV-1 in culture media. Medium spiked with high titers of HIV-1 was exposed to copper oxide powder or copper oxide-impregnated fibers or passed through copper-based filters, and the infectious viral titers before and after treatment were determined. Cell-free and cell-associated HIV-1 infectivity was inhibited when exposed to copper oxide in a dose-dependent manner, without cytotoxicity at the active antiviral copper concentrations. Similar dose-dependent inhibition occurred when HIV-1 was exposed to copper-impregnated fibers. Filtration of HIV-1 through filters containing the copper powder or copper-impregnated fibers resulted in viral deactivation of all 12 wild-type or drug-resistant laboratory or clinical, macrophage-tropic and T-cell-tropic, clade A, B, or C, HIV-1 isolates tested. Viral inactivation was not strain specific. Thus, a novel means to inactivate HIV-1 in medium has been developed. This inexpensive methodology may significantly reduce HIV-1 transmission from “mother to child” and/or through blood donations if proven to be effective in breast milk or plasma and safe for use. The successful application of this technology may impact HIV-1 transmission, especially in developing countries where HIV-1 is rampant.
New Genetic Element Carrying the Erythromycin Resistance Determinant
erm
(TR) in
Streptococcus pneumoniae
Authors: Camilli Romina , Del Grosso Maria , Iannelli Francesco , Pantosti Annalisa 
Published: December 2007

ABSTRACT

erm
(A) subclass
erm
(TR), a common macrolide resistance determinant in
Streptococcus pyogenes
but quite rare in
Streptococcus pneumoniae
, was found in a clinical
S. pneumoniae
isolate (AP200) from Italy. In this isolate,
erm
(TR) was found included in a genetic element approximately 56 kb in size that did not appear to be conjugative but could be transferred by transformation. An
erm
(TR)-containing DNA fragment of approximately 10 kb was sequenced and 12 open reading frames (ORFs) were identified. Upstream of
erm
(TR), a regulatory protein of the TetR family and the two components of an efflux pump of the ABC type were found. Downstream of
erm
(TR), there were ORFs homologous to a spectinomycin phosphotransferase, transposases, and a relaxase. Since the genomic sequence of
S. pyogenes
MGAS10750 carrying
erm
(TR) became available, comparison between the
erm
(TR)-containing genetic elements in AP200 and in MGAS10750 was performed. The region flanking
erm
(TR) in MGAS10750 showed identity with AP200 for 10 ORFs out of 12. PCR mapping using primers designed on the sequence of MGAS10750 confirmed that AP200 carries a genetic element similar to that of MGAS10750. In AP200 the genetic element was inserted inside an ORF homologous to spr0790 of
S. pneumoniae
R6, coding for a type I restriction modification system. Homologies between the insertion sites in AP200 and MGAS10750 consisted of eight conserved nucleotides, of which three were duplicated, likely representing target site duplication. The structure of the
erm
(TR)-carrying genetic element shows characteristics of a transposon/prophage remnant chimera. In AP200 this genetic element was designated Tn
1806
.
Antimicrobial Activities of Tigecycline and Other Broad-Spectrum Antimicrobials Tested against Serine Carbapenemase- and Metallo-β-Lactamase-Producing
Enterobacteriaceae
: Report from the SENTRY Antimicrobial Surveillance Program
Authors: Castanheira Mariana , Sader Hélio S. , Deshpande Lalitagauri M. , Fritsche Thomas R. , Jones Ronald N. 
Published: December 2007

ABSTRACT

A total of 104 carbapenemase (serine- and metallo-β-lactamase [MβL])-producing strains of the
Enterobacteriaceae
family collected from 2000 to 2005 in medical centers distributed worldwide were tested against tigecycline and 25 comparators by reference broth microdilution methods. The most frequent carbapenemase was KPC-2 or -3 (73 strains), followed by VIM-1 (14), IMP-1 (11), SME-2 (5), and NMC-A (1). All serine carbapenemases were detected in the United States, while MβL-producing strains were isolated in Europe. Carbapenemase-producing
Enterobacteriaceae
showed high rates of resistance to most antimicrobial agents tested. The rank order of in vitro activity against these strains was as follows: tigecycline (100.0% susceptible) > polymyxin B (88.1%) > amikacin (73.0%) > imipenem (37.5%). Tigecycline was very active (MIC
90
, 1 μg/ml) against this significant, contemporary collection of well-characterized strains and appears to be an excellent option compared to the polymyxins for treatment of infections caused by these multidrug-resistant
Enterobacteriaceae
.