Abstract:
:Helix alpha 4 of Bacillus thuringiensis Cry toxins is thought to play a critical role in the toxins' mode of action. Accordingly, single-site substitutions of many Cry1Aa helix alpha 4 amino acid residues have previously been shown to cause substantial reductions in the protein's pore-forming activity. Changes in protein structure and formation of intermolecular disulfide bonds were investigated as possible factors responsible for the inactivity of these mutants. Incubation of each mutant with trypsin and chymotrypsin for 12 h did not reveal overt structural differences with Cry1Aa, although circular dichroism was slightly decreased in the 190- to 210-nm region for the I132C, S139C, and V150C mutants. The addition of dithiothreitol stimulated pore formation by the E128C, I132C, S139C, T142C, I145C, P146C, and V150C mutants. However, in the presence of these mutants, the membrane permeability never reached that measured for Cry1Aa, indicating that the formation of disulfide bridges could only partially explain their loss of activity. The ability of a number of inactive mutants to compete with wild-type Cry1Aa for pore formation in brush border membrane vesicles isolated from Manduca sexta was also investigated with an osmotic swelling assay. With the exception of the L147C mutant, all mutants tested could inhibit the formation of pores by Cry1Aa, indicating that they retained receptor binding ability. These results strongly suggest that helix alpha 4 is involved mainly in the postbinding steps of pore formation.
journal_name
Appl Environ Microbioljournal_title
Applied and environmental microbiologyauthors
Girard F,Vachon V,Préfontaine G,Marceau L,Schwartz JL,Masson L,Laprade Rdoi
10.1128/AEM.01930-08subject
Has Abstractpub_date
2009-01-01 00:00:00pages
359-65issue
2eissn
0099-2240issn
1098-5336pii
AEM.01930-08journal_volume
75pub_type
杂志文章abstract::A database was probed with artificial neural network (ANN) and multivariate logistic regression (MLR) models to investigate the efficacy of predicting PCR-identified human adenovirus (ADV), Norwalk-like virus (NLV), and enterovirus (EV) presence or absence in shellfish harvested from diverse countries in Europe (Spain...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.71.9.5244-5253.2005
更新日期:2005-09-01 00:00:00
abstract::In this article, we present a new bioluminescent test system for the screening of chemical compounds with an inhibitory effect on protein synthesis. The test is based on the measurement of real-time in vivo light production by Escherichia coli strains expressing different luciferase genes. The eukaryotic lucGR gene fr...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.61.8.2981-2989.1995
更新日期:1995-08-01 00:00:00
abstract::Receptors on the cell surfaces of bacterial hosts are essential during the infection cycle of bacteriophages. To date, the phage receptors of the industrial relevant dairy starter bacterium Streptococcus thermophilus remain elusive. Thus, we set out to identify cell surface structures that are involved in host recogni...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01847-18
更新日期:2018-11-15 00:00:00
abstract::Scanning and transmission electron microscopy were used to examine the adherence and in situ morphology of the microbial community colonizing the anal and vulvar pores of the subfamily Cyathostominae (Nematoda: Strongylidae) from the colon of Burchell's zebra (Equus burchelli antiquorum). Two different morphological t...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.55.5.1178-1186.1989
更新日期:1989-05-01 00:00:00
abstract::A triplex reverse transcriptase PCR (RT-PCR) was developed to simultaneously detect poliovirus, hepatitis A virus (HAV), and rotavirus in sewage and ocean water. Sewage and ocean water samples seeded with the three different viruses were concentrated by ultrafiltration. The unseeded ocean water and sewage samples were...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.60.7.2400-2407.1994
更新日期:1994-07-01 00:00:00
abstract::Mycobiota growing on food is often beneficial for the ripening and development of the specific flavor characteristics of the product, but it can also be harmful due to the production of undesirable compounds such as mycotoxins or antibiotics. Some of the fungi most frequently isolated from fermented and cured meat pro...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.68.3.1211-1219.2002
更新日期:2002-03-01 00:00:00
abstract::Higher yields of sterigmatocystin were obtained with Aspergillus versicolor than with Bipolaris sorokiniana both in liquid and on solid media. The optimum temperature for sterigmatocystin production by A. versicolor was 27 to 29 degrees C and 23 degrees C for B. sorokiniana. In liquid shake cultures, production of ste...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.32.2.206-208.1976
更新日期:1976-08-01 00:00:00
abstract::Cyanobacterial hepatotoxins, microcystins, are specific inhibitors of serine/threonine protein phosphatases and potent tumor promoters. They have caused several poisonings of animals and also pose a health hazard for humans through the use of water for drinking and recreation. Different strains of the same cyanobacter...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.63.6.2206-2212.1997
更新日期:1997-06-01 00:00:00
abstract::Recreational and potable water supplies polluted with human wastewater can pose a direct health risk to humans. Therefore, sensitive detection of human fecal pollution in environmental waters is very important to water quality authorities around the globe. Microbial source tracking (MST) utilizes human fecal markers (...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.03765-15
更新日期:2015-12-18 00:00:00
abstract::A light cycler-based real-time PCR (LC-PCR) assay that amplifies the F57 sequence of Mycobacterium avium subsp. paratuberculosis was developed. This assay also includes an internal amplification control template to monitor the amplification conditions in each reaction. The targeted F57 sequence element is unique for M...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.71.10.5957-5968.2005
更新日期:2005-10-01 00:00:00
abstract::The actions of cyclomaltodextrin glucanotransferases (CGTase; EC 2.4.1.19) from alkalophilic Bacillus sp. strain A2-5a (A2-5a CGTase), Bacillus macerans (Bmac CGTase), and Bacillus stearothermophilus (Bste CGTase) on amylose were investigated. All three enzymes produced large cyclic alpha-1,4-glucans (cycloamyloses) a...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.67.4.1453-1460.2001
更新日期:2001-04-01 00:00:00
abstract::Erwinia amylovora bacteriophages (phages) belonging to the Myoviridae and Podoviridae families demonstrated a preference for either high-exopolysaccharide-producing (HEP) or low-exopolysaccharide-producing (LEP) bacterial hosts when grown on artificial medium without or with sugar supplementation. Myoviridae phages pr...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00067-13
更新日期:2013-05-01 00:00:00
abstract::We report the construction of an Escherichia coli mutant that harbors two compatible plasmids and that is able to synthesize labeled 2-O-alpha-D-mannosyl-D-glycerate from externally added labeled mannose without the loss of specific isotopic enrichment. The strain carries a deletion in the manA gene, encoding phosphom...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.69.1.233-240.2003
更新日期:2003-01-01 00:00:00
abstract::A multilocus enzyme electrophoresis analysis of 96 strains of the salmonellae distinguished 80 electrophoretic types (ETs) and placed them in eight groups, seven of which correspond precisely to the seven taxonomic groups (I, II, IIIa, IIIb, IV, V, and VI) previously defined on the basis of biotype and genomic DNA hyb...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.62.3.804-808.1996
更新日期:1996-03-01 00:00:00
abstract::Mannitol, a six-carbon sugar alcohol, is the main storage carbon in the button mushroom, Agaricus bisporus. Given the physiological importance of mannitol metabolism in growth, fruit body development, and salt tolerance of A. bisporus, the enzyme responsible for mannitol biosynthesis, NADP-dependent mannitol dehydroge...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.64.12.4689-4696.1998
更新日期:1998-12-01 00:00:00
abstract::Difluoromethane (HFC-32; DFM) is compared to acetylene and methyl fluoride as an inhibitor of methanotrophy in cultures and soils. DFM was found to be a reversible inhibitor of CH4 oxidation by Methylococcus capsulatus (Bath). Consumption of CH4 in soil was blocked by additions of low levels of DFM (0.03 kPa), and thi...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.64.11.4357-4362.1998
更新日期:1998-11-01 00:00:00
abstract::Many Helicobacter pylori genetic studies would benefit from an ability to move DNA sequences easily between strains by transformation and homologous recombination, without needing to leave a conventional drug resistance determinant at the targeted locus. Presented here is a two-gene cassette that can be selected both ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01135-06
更新日期:2006-09-01 00:00:00
abstract::A 5' nuclease assay has been developed to detect viable Listeria monocytogenes. The assay targets the hemolysin A (hlyA) transcript, which is found only in L. monocytogenes. The single-tube, reverse transcriptase (RT), fluorogenic probe-based assay was formatted by using Tth DNA polymerase whose activity was modulated...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.65.5.2122-2127.1999
更新日期:1999-05-01 00:00:00
abstract::A collection of 300 isolates of fluorescent pseudomonads was established from Douglas fir-Laccaria bicolor mycorrhizas and mycorrhizosphere and from adjacent bulk soil. These isolates were first phenotypically characterized with the Biolog method. Taxonomic identification assigned 90% of the isolates to the different ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.63.5.1852-1860.1997
更新日期:1997-05-01 00:00:00
abstract::The bacterial second messengers (p)ppGpp and bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) regulate important functions, such as transcription, virulence, biofilm formation, and quorum sensing. In mycobacteria, they regulate long-term survival during starvation, pathogenicity, and dormancy. Recently, a Pseudomonas aerugin...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.03999-14
更新日期:2015-04-01 00:00:00
abstract::The detection and enumeration of most cultivable human enteric viruses from water is possible if samples are first inoculated onto a suitable cell line such as MA-104 or BGM. Virus growth is then detected by an indirect immunoperoxidase method with human immune serum globulin as the source of antibody to most enteric ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.50.5.1308-1310.1985
更新日期:1985-11-01 00:00:00
abstract::Legionella pneumophila is an intracellular parasite of protozoa and human phagocytes. To examine adaptation of this bacterium to parasitize protozoa, the sequence of events of the intracellular infection of the amoeba Hartmannella vermiformis was examined. The previously described uptake phenomenon of coiling phagocyt...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.62.6.2022-2028.1996
更新日期:1996-06-01 00:00:00
abstract::Methanol is already an important carbon feedstock in the chemical industry, but it has found only limited application in biotechnological production processes. This can be mostly attributed to the inability of most microbial platform organisms to utilize methanol as a carbon and energy source. With the aim to turn met...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.03110-14
更新日期:2015-03-01 00:00:00
abstract::Conditions for detection and quantitation of Clostridium perfringens enterotoxin by counterimmunoelectrophoresis are described. As little as 0.2 microgram of enterotoxin per ml could be detected. The test was found to be rapid, sensitive, specific and easy for the detection and quantitation of enterotoxin. ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.34.2.125-128.1977
更新日期:1977-08-01 00:00:00
abstract::Rhizoremediation of organic chemicals requires high-level expression of biodegradation genes in bacterial strains that are excellent rhizosphere colonizers. Pseudomonas fluorescens F113 is a biocontrol strain that was shown to be an excellent colonizer of numerous plant rhizospheres, including alfalfa. Although a deri...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.71.5.2687-2694.2005
更新日期:2005-05-01 00:00:00
abstract::The diversity of microcystin-producing cyanobacteria in the western basin of Lake Erie was studied using sequence analysis of mcyA gene fragments. Distinct populations of potentially toxic Microcystis and Planktothrix were found in spatially isolated locations. This study highlights previously undocumented diversity o...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00312-06
更新日期:2006-07-01 00:00:00
abstract::Many microorganisms produce surface-active substances that enhance the availability of water-insoluble substrates. Although many of these biosurfactants have interesting potential applications, very little is known about their biosynthesis. The basidiomycetous fungus Ustilago maydis secretes large amounts of mannosyle...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00506-06
更新日期:2006-08-01 00:00:00
abstract::A spoilage organism isolated from turbid beer is described. The bacterium was gram negative, catalase negative, strictly anaerobic, and rod shaped, having flagella only on one side of the cell. The main metabolic product was propionic acid. In addition acetic, succinic, and lactic acids and acetoin were formed. Malona...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.41.2.511-517.1981
更新日期:1981-02-01 00:00:00
abstract::Desulfitobacterium frappieri PCP-1 was induced for ortho- and para-dechlorinating activities by different chlorophenols. Dehalogenation rates ranging from 25 to 1,158 nmol/min/mg of cell protein were observed according to the chlorophenol tested and the position of the chlorine removed. D. frappieri shows a broad subs...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.64.11.4603-4606.1998
更新日期:1998-11-01 00:00:00
abstract::In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicyla...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.67.3.1190-1197.2001
更新日期:2001-03-01 00:00:00