Bacteriology

Which heat process value F should a particular food receive to make it safe and shelf stable?
* Section 1 lists reported sterilization values F0 = F zero (reference temperature 121.1 oC; z = 10 oC) for commercial food preservation processes of all types of food products, for several package sizes and types.
* Section2 contains reported pasteurization values F, or P, of a great variety of foods. The required storage conditions of the pasteurized foods, either at ambient temperature, or refrigerated (4 - 7 °C), are indicated.
* Section 3 shows a decision scheme: should a particular food be pasteurized or sterilized? This depends on the intended storage temperature (refrigerated or ambient) after heating, the required shelf life (7 days to 4 years), the food pH (high acid, acid, or low acid), the food water activity aW, and on the presence of preservatives such as nitrite (E250) mixed with salt NaCl, or nisin.
* In Section 4, two worked examples are presented on how to use an F value when calculating the actual sterilization time Pt:
- C.R. Stumbo’s (1973) calculation method has been manually applied, verified by computer program STUMBO.exe, to find the sterilization time and the thiamine retention of bottled liquid milk in a rotating steam retort;
- O.T. Pham’s (1987; 1990) formula method,  incorporated in Excel program “Heat Process calculations according to Pham.xls”, has been used  to find the sterilization time and the nutrient retention of canned carrot purée in a still steam retort.
* The worked example in Section 5 illustrates the use of the pasteurization value F of apple juice, in calculating the required (average) residence time in the holding tube of a heat exchanger. The Excel program Build-Heat-Exchanger.xls next calculates the juice’s spoilage rate by a mold, a yeast and an enzyme, and the nutrient retention of vitamins C and folic acid in the pasteurized juice.
* Section 6 explains how F values can be calculated when a microbial analysis of the food is available. The actual pasteurization or sterilization time calculations should be based on all micro-organisms of concern present, and rather NOT on the highest F value only!
An example calculation shows that the required F value for a food, to be sold in a moderate climate country, usually differs considerably from the F, required  for the same food, to be sold in tropical areas.

Methylomonas methanica MC09 is a mesophilic, halotolerant, aerobic, methanotrophic member of the Gammaproteobacteria , isolated from coastal seawater. Here we present the complete genome sequence of this strain, the first available from an aerobic marine methanotroph.

A modified gel electrophoresis technique provided a reproducible way of detecting and isolating plasmids with molecular weights ranging from 12 X 10(6) to 370 X 10(6) for Azospirillum species. Analysis with the nifHD region of Rhizobium trifolii showed that the Azospirillum nif genes were chromosomally located in all eight strains investigated and not on endogenous plasmids.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine available against tuberculosis, and the strains used worldwide represent a family of daughter strains with distinct genotypic characteristics. Here we report the complete genome sequence of M. bovis BCG Moreau, the strain in continuous use in Brazil for vaccine production since the 1920s.

Archaea are abundant and drive critical microbial processes in the Earth's cold biosphere. Despite this, not enough is known about the molecular mechanisms of cold adaptation and no biochemical studies have been performed on stenopsychrophilic archaea (e.g., Methanogenium frigidum). This study examined the structural and functional properties of cold shock proteins (Csps) from archaea, including biochemical analysis of the Csp from M. frigidum. csp genes are present in most bacteria and some eucarya but absent from most archaeal genome sequences, most notably, those of all archaeal thermophiles and hyperthermophiles. In bacteria, Csps are small, nucleic acid binding proteins involved in a variety of cellular processes, such as transcription. In this study, archaeal Csp function was assessed by examining the ability of csp genes from psychrophilic and mesophilic Euryarchaeota and Crenarchaeota to complement a cold-sensitive growth defect in Escherichia coli. In addition, an archaeal gene with a cold shock domain (CSD) fold but little sequence identity to Csps was also examined. Genes encoding Csps or a CSD structural analog from three psychrophilic archaea rescued the E. coli growth defect. The three proteins were predicted to have a higher content of solvent-exposed basic residues than the noncomplementing proteins, and the basic residues were located on the nucleic acid binding surface, similar to their arrangement in E. coli CspA. The M. frigidum Csp was purified and found to be a single-domain protein that folds by a reversible two-state mechanism and to exhibit a low conformational stability typical of cold-adapted proteins. Moreover, M. frigidum Csp was characterized as binding E. coli single-stranded RNA, consistent with its ability to complement function in E. coli. The studies show that some Csp and CSD fold proteins have retained sufficient similarity throughout evolution in the Archaea to be able to function effectively in the Bacteria and that the function of the archaeal proteins relates to cold adaptation. The initial biochemical analysis of M. frigidum Csp has developed a platform for further characterization and demonstrates the potential for expanding molecular studies of proteins from this important archaeal stenopsychrophile.

The cell reproduction of Mycoplasma capricolum was studied. The velocity of DNA replication fork progres- sion was about 6 kb/min, which is 10 times slower than that of Escherichia coli. The time required for one round of DNA replication accorded with the doubling time. The origin/terminus ratio was 2.0. M. capricolum cell morphology was classified into two types, rod and

Bacterial surface proteins are important molecules in the infectivity and survival of pathogens. Surface proteins on gram-positive bacteria have been shown to attach via a transpeptidase, termed sortase, that cleaves an LPXTG sequence found close to the C termini of nearly all surface proteins on these bacteria. We previously identified a unique enzyme (LPXTGase) from Streptococcus pyogenes that also cleaves the LPXTG motif with a catalytic activity higher than that of sortase, suggesting that it plays an important role in the attachment process. We have now purified and characterized an LPXTGase from Staphylococcus aureus and found that it has both similar and unique features compared to the S. pyogenes enzyme. The S. aureus enzyme is glycosylated and contains unusual amino acids, like its streptococcal counterpart. Like the streptococcal enzyme, staphylococcal LPXTGase has an overrepresentation of amino acids found in the peptidoglycan, i.e., glutamine/glutamic acid, glycine, alan...

Green sulfur bacteria were first obtained in pure culture and studied under controlled conditions by . He isolated several strains which, on the basis of their morphology, were identified as Chlorobium limicola . Physiologically the species was characterized as strictly anaerobic, obligatorily photosynthetic, requiring H25 for growth. The sulfide was quantitatively oxidized to sulfur with concomitant reduction of C02. The asimilatory process could be approximately expressed by the equation: C02 + 2H2S light (CH20) + H20 + 2S in which (CH20) denotes the average reduction level of the aimilation products.

The carboxysomes of Thiobacillus neapolitanus are shown, by electron microscopy, to consist of a paracrystalline array of 10-nm particles surrounded by a "membrane." The 10-nm particles have a center hole or depression and have been previously identified as ribulose diphosphate carboxylase. The membrane is a monolayer approximately 3.5-nm thick.

Sulfolobus acidocaldarius is an aerobic thermoacidophilic crenarchaeon which grows optimally at 80°C and pH 2 in terrestrial solfataric springs. Here, we describe the genome sequence of strain DSM639, which has been used for many seminal studies on archaeal and crenarchaeal biology. The circular genome carries 2,225,959 bp (37% G؉C) with 2,292 predicted protein-encoding genes. Many of the smaller genes were identified for the first time on the basis of comparison of three Sulfolobus genome sequences. Of the protein-coding genes, 305 are exclusive to S. acidocaldarius and 866 are specific to the Sulfolobus genus. Moreover, 82 genes for untranslated RNAs were identified and annotated. Owing to the probable absence of active autonomous and nonautonomous mobile elements, the genome stability and organization of S. acidocaldarius differ radically from those of Sulfolobus solfataricus and Sulfolobus tokodaii. The S. acidocaldarius genome contains an integrated, and probably encaptured, pARN-type conjugative plasmid which may facilitate intercellular chromosomal gene exchange in S. acidocaldarius. Moreover, it contains genes for a characteristic restriction modification system, a UV damage excision repair system, thermopsin, and an aromatic ring dioxygenase, all of which are absent from genomes of other Sulfolobus species. However, it lacks genes for some of their sugar transporters, consistent with it growing on a more limited range of carbon sources. These results, together with the many newly identified protein-coding genes for Sulfolobus, are incorporated into a public Sulfolobus database which can be accessed at http://dac.molbio.ku.dk/dbs/Sulfolobus. . † The paper is dedicated to the memory of Wolfram Zillig, one of the founders of Sulfolobus molecular biology. 4994 CHEN ET AL. J. BACTERIOL. FIG. 4. Putative Cdc6 binding sites in S. acidocaldarius. (A) The three ORB sequences in S. acidocaldarius (S.a. ORB1 to -3) compared to the consensus ORB sequences in S. solfataricus and S. tokodaii (S.s. and S.t. ORB) (48), where dots indicate nonconserved bases. The genome map shows the position of the sequences relative to cdc6-1. (B) S. acidocaldarius sequences which are similar to Cdc6-2 and Cdc6-3 binding sites (48). The genome map indicates the positions of the sequences relative to cdc6-3. 4996 CHEN ET AL. J. BACTERIOL.

Stalk formation is a novel pattern of multicellular organization. Yeast cells which survive UV irradiation form colonies that grow vertically to form very long (0.5 to 3.0 cm) and thin (0.5 to 4 mm in diameter) multicellular structures. We describe the conditions required to obtain these stalk-like structures reproducibly in large numbers. Yeast mutants, mutated for control of cell polarity, developmental processes, UV response, and signal transduction cascades were tested and found capable of forming stalk-like structures. We suggest a model that explains the mechanism of stalk formation by mechanical environmental forces. We show that other microorganisms (Candida albicans, Schizosaccharomyces pombe, and Escherichia coli) also form stalks, suggesting that the ability to produce stalks may be a general property of microorganisms. Diploid yeast stalks sporulate at an elevated frequency, raising the possibility that the physiological role of stalks might be disseminating spores.

The ability of stationary-phase cells of Escherichia coli W7 to incorporate radioactive precursorsinto macromolecular murein has been studied. During the initial 6 h of the stationary phase, resting cells incorporated meso-[3H]diaminopimelic acid at a rate corresponding to theinsertion ...

Pathogenic bacteria are microorganisms capable of producing disease. Dangerous bacterial pathogens, such as Staphylococcus aureus , Pseudomonas aeruginosa , and Acinetobacter baumannii , are responsible for serious intrahospital and community infections in humans.

Genes for the biosynthesis of daunorubicin (daunomycin) and doxorubicin (adriamycin), important antitumor drugs, were cloned from Streptomycespeucetius (the daunorubicin producer) and S. peucetius subsp. caesius (the doxorubicin producer) by use of the actIltemla and actII polyketide synthase gene probes. Restriction mapping and Southern analysis of the DNA cloned in a cosmid vector established that the DNA represented three nonoverlapping regions of the S. peucetius subsp. caesius genome. These three regions plus an additional one that hybridized to the same probes are present in the S. peucetius genome, as reported previously (K. J. Stutzman-Engwall and C. R. Hutchinson, Proc. Natl. Acad. Sci. USA 86:3135-3139, 1989). Functional analysis of representative clones from some of these regions in S. lividans, S. peucetius ATCC 29050, S. peucetius subsp. caesius ATCC 27952, and two of its blocked mutants (strains H6101 and H6125) showed that many of the antibiotic production genes reside in the region of DNA represented by the group IV clones. This conclusion is based on the production of r-rhodomycinone, a key intermediate of the daunorubicin pathway, in certain S. lividans transformants and on the apparent complementation of mutations that block daunorubicin biosynthesis in strains H6101 and H6125. Some of the transformants of strains 29050, 27952, and H6125 exhibited substantial overproduction of r-rhodomycinone and daunorubicin.

The proteins belonging to the Fur family are global regulators of gene expression involved in the response to several environmental stresses and to the maintenance of divalent cation homeostasis. The Mycobacterium tuberculosis genome encodes two Fur-like proteins, FurA and a protein formerly annotated FurB. Since in this paper we show that it represents a zinc uptake regulator, we refer to it as Zur. The gene encoding Zur is found in an operon together with the gene encoding a second transcriptional regulator (Rv2358). In a previous work we demonstrated that Rv2358 is responsible for the zinc-dependent repression of the Rv2358-zur operon, favoring the hypothesis that these genes represent key regulators of zinc homeostasis. In this study we generated a zur mutant in M. tuberculosis, examined its phenotype, and characterized the Zur regulon by DNA microarray analysis. Thirty-two genes, presumably organized in 16 operons, were found to be upregulated in the zur mutant. Twenty-four of them belonged to eight putative transcriptional units preceded by a conserved 26-bp palindrome. Electrophoretic mobility shift experiments demonstrated that Zur binds to this palindrome in a zinc-dependent manner, suggesting its direct regulation of these genes. The proteins encoded by Zurregulated genes include a group of ribosomal proteins, three putative metal transporters, the proteins belonging to early secretory antigen target 6 (ESAT-6) cluster 3, and three additional proteins belonging to the ESAT-6/culture filtrate protein 10 (CFP-10) family known to contain immunodominant epitopes in the T-cell response to M. tuberculosis infection.

We present a complete DNA sequence and metabolic analysis of the dominant oral bacterium Fusobacterium nucleatum. Although not considered a major dental pathogen on its own, this anaerobe facilitates the aggregation and establishment of several other species including the dental pathogens Porphyromonas gingivalis and Bacteroides forsythus. The F. nucleatum strain ATCC 25586 genome was assembled from shotgun sequences and analyzed using the ERGO bioinformatics suite (http://www.integratedgenomics.com). The genome contains 2.17 Mb encoding 2,067 open reading frames, organized on a single circular chromosome with 27% GC content. Despite its taxonomic position among the gram-negative bacteria, several features of its core metabolism are similar to that of gram-positive Clostridium spp., Enterococcus spp., and Lactococcus spp. The genome analysis has revealed several key aspects of the pathways of organic acid, amino acid, carbohydrate, and lipid metabolism. Nine very-high-molecular-weight outer membrane proteins are predicted from the sequence, none of which has been reported in the literature. More than 137 transporters for the uptake of a variety of substrates such as peptides, sugars, metal ions, and cofactors have been identified. Biosynthetic pathways exist for only three amino acids: glutamate, aspartate, and asparagine. The remaining amino acids are imported as such or as di-or oligopeptides that are subsequently degraded in the cytoplasm. A principal source of energy appears to be the fermentation of glutamate to butyrate. Additionally, desulfuration of cysteine and methionine yields ammonia, H 2 S, methyl mercaptan, and butyrate, which are capable of arresting fibroblast growth, thus preventing wound healing and aiding penetration of the gingival epithelium. The metabolic capabilities of F. nucleatum revealed by its genome are therefore consistent with its specialized niche in the mouth. Fusobacterium nucleatum is a gram-negative anaerobe, which belongs to the Bacteroidaceae family and is found naturally in the microflora of the mouth in healthy or diseased humans. F. nucleatum is a very long rod with tapering ends and is one of the dominant species of the 500 or more organisms that coexist in the oral cavity (21). Many of the oral flora are commensals but a few are opportunistic pathogens. F. nucleatum can be isolated not only from the mouth but also from infections such as skin ulcers, peritonsillar abscesses, septic arthritis, and endocarditis (5). Several species of Fusobacterium have been isolated and studied, including F. necrophorum (the causative agent of Lemierre's syndrome), F. ulcercans (skin ulcers), F. russi (animal bite infections), and F. varium (eye infections), with F. nucleatum and F. necrophorum considered to be the most pathogenic. In the initial stages of the periodontal disease process, saccharolytic, aerobic Streptococcus spp. and other bacteria adhere to and colonize the tooth enamel and root surface. This sets the stage for F. nucleatum to coaggregate with these early colonizers and to permit late colonizers, including dental pathogens, to eventually form a biofilm. These complex interactions result in the release of factors that lead to tooth decay. Physical interaction is very specific among various genera in this complex microbial community. Due to the unusual length, adhesive nature, and other cell surface properties of F. nucleatum, periodontal disease-causing bacteria such as Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Treponema denticola, and Streptococcus spp. aggregate and thrive; hence, F. nucleatum is referred to as a "bridge bacterium" (5). The interaction between F. nucleatum and P. gingivalis has been reported to be very specific (19), mediated by a lactose-binding adhesin (20). The same adhesin protein mediates the binding of F. nucleatum to a variety of eukaryotic cell types including HeLa cells, buccal epithelial cells, macrophages, polymorphonuclear leukocytes, and gingival and periodontal ligaments (46). Helicobacter pylori was also shown to adhere selectively to F. nucleatum (1). Research on Fusobacterium spp. has focused primarily on species identification, oral ecology, cell-cell communication, extracellular surfaces, amino acid degradation, carbohydrate metabolism, organic acid fermentation, and antibiotic resistance (5, 21). However, many metabolic pathways and their roles in survival in such specialized niches are not known. Genetic experiments have been hampered by the lack of molecular tools, although recently three plasmids, pFN1, pFN2, and pFN3, have been isolated and sequenced from the strain ATCC 10953. A transformation system has been developed for gene manipulation using the pFN1 ori sequence (14). Although many potential virulence candidates have been

ABSTRACT
Oral cavity of eight (8) Noma patients were swabbed at the Noma Children Hospital Sokoto in duplicates. The first eight swabbed were placed into nutrient broth and its duplicates were placed into MacConkey broth. They were incubated for 24hours after which that of nutrient broth was sub-cultured into nutrient agar and its duplicate in MacConkey broth was also subcultured  into MacConkey agar and incubated for another 24hours. The colonies from MacConkey agar were sub-culture into nutrient agar for pure isolates, while result showed that a total of 9 bacteria were isolated, characterized and identified. These organisms according to there frequency of occurrence were: Staphylococcus aureaus (11.1%), Escherichia coli (33.3%), Fusobacterium spp (5.5%), Fusobacterium necrophorum (5.5%), Pseudomonas aeruginosa (22.2%), Streptococcus gallinarum (5.5%), Streptococcus pycogenes (5.5%), Micrococcus loteus (5.5%), Staphylococcus heamolyticus. Although these micro organisms are normal flora in the oral cavity of human but can become pathogenic when the immune system is suppressed, due to malnutrition of concomitant infection (any of the childhood disease). 
 

Sedimentary hopanes are pentacyclic triterpenoids that serve as biomarker proxies for bacteria and certain bacterial metabolisms, such as oxygenic photosynthesis and aerobic methanotrophy. Their parent molecules, the bacteriohopanepolyols (BHPs), have been hypothesized to be the bacterial equivalent of sterols. However, the actual function of BHPs in bacterial cells is poorly understood. Here, we report the physiological study of a mutant in Rhodopseudomonas palustris TIE-1 that is unable to produce any hopanoids. The deletion of the gene encoding the squalene-hopene cyclase protein (Shc), which cyclizes squalene to the basic hopene structure, resulted in a strain that no longer produced any polycyclic triterpenoids. This strain was able to grow chemoheterotrophically, photoheterotrophically, and photoautotrophically, demonstrating that hopanoids are not required for growth under normal conditions. A severe growth defect, as well as significant morphological damage, was observed when cells were grown under acidic and alkaline conditions. Although minimal changes in shc transcript expression were observed under certain conditions of pH shock, the total amount of hopanoid production was unaffected; however, the abundance of methylated hopanoids significantly increased. This suggests that hopanoids may play an indirect role in pH homeostasis, with certain hopanoid derivatives being of particular importance.

Growth of Erwinia chrysanthemi in media of elevated osmolarity can be achieved by the uptake and accumulation of various osmoprotectants. This study deals with the cloning and sequencing of the ousA gene-encoded osmoprotectant uptake system A from E. chrysanthemi 3937. OusA belongs to the superfamily of solute ion cotransporters. This osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and protein function with the proline/betaine porter of Escherichia coli encoded by proP. The control of ousA expression is clearly different from that of proP. It is induced by osmotic strength and repressed by osmoprotectants. Its expression in E. coli is controlled by H-NS and is rpoS dependent in the exponential phase but unaffected by the stationary phase.

To prevent infective endocarditis (IE), Australian guidelines recommend providing prophylactic antibiotics to Indigenous patients with rheumatic heart disease (RHD) prior to procedures which may cause bacteremia. In northern Australia RHD remains prevalent. We aimed to determine whether RHD is associated with an increased risk of IE, which risk factors are associated with IE, and the incidence and aetiology of IE.

Seventeen rhizobacteria isolated from different ecological regions, i.e. Brazil, Indonesia, Mongolia and Pakistan were studied to develop inoculants for wheat, maize and rice. Almost all the bacterial isolates were Gram-negative, fast-growing motile rods and utilized a wide range of carbon sources. These isolates produced indole-3-acetic acid at concentrations ranging from 0.8-42.1 µg/mL, irrespective of the region. Fifteen isolates fixed N at rates ranging from 20.3-556.8 nmole C 2 H 2 reduced/h/vial. Isolate 8N-4 from Mongolia produced the highest amount of indole-3-acetic acid (42.1 µg/mL), produced siderophores (0.3 mg/mL) and was the only isolate that solubilized phosphate (188.7 µg P/mL). Inoculation of the wheat variety Orkhon with 8N-4 isolate resulted in the maximum increase in plant biomass, root length, and total N and P contents in plants. Random amplified polymorphic deoxyribonucleic acid (RAPD) analysis, conducted with 60 decamer primers, revealed a high level of polymorphism among the bacterial isolates from different geographic regions and a low level of polymorphism among isolates from the same region. The complete 16S rRNA gene sequence analysis demonstrated that 8N-4 is a Bacillus pumilus strain (Accession number AY548949). It was concluded that Bacillus pumilus 8N-4 can be used as a bio-inoculant for biofertilizer production to increase the crop yield of wheat variety Orkhon in Mongolia. Rhizobacteria / genetic diversity / RAPD

Inorganic phosphate (Pi) transport by wild-type cells of Escherichia coli grown in excess phosphate-containing media involves two genetically separable transport systems. Cells dependent upon the high affinity-low velocity Pst (phosphate specific transport) system have a Km of 0.43 ± 0.2 ,uM Pi and a Vm of 15.9 ± 0.3 nmol of Pi (mg [dry weight]-1minn') and will grow in the presence of arsenate in the medium. However, cells dependent upon the low affinity-high velocity Pit (Pi transport) system have a Km of 38.2 ± 0.4 p1M and a V. of 55 ± 1.9 nmol of Pi (mg [dry weight]-1min-1), and these cells cannot grow in the presence of an arsenate-to-Pi ratio of 10 in the medium. Pi transport by both systems was sensitive to the energy uncoupler 2,4-dinitrophenol and the sulflhydryl reagent Nethylmaleimide, whereas only the Pst system was very sensitive to sodium cyanide. Evidence is presented that Pi is transported as Pi or a very labile intermediate and that accumulated Pi does not exit through the Pst or Pit systems from glucose-grown cells. Kinetic analysis of Pi transport in the wild-type strain containing both the Pst and Pit transport systems revealed that each system was not operating at full capacity. In addition, Pi transport in the wild-type strain was completely sensitive to sodium cyanide (a characteristic of the Pst system).

Conventional agriculture has had major environmental impacts, in particular with respect to soil degradation. Soil structure, fertility, microbial and faunal biodiversity have declined, and root diseases are common unless genetic resistance, soil fumigation and/or seed treatments are used. Primarily for environmental reasons and increasing demands for safe and healthy food from the public, farmers have switched over to organic production at an increasing rate. During a transition period of about 5 years, organic farmers may face problems with yield losses and pest or disease problems. However, in well-managed, long-term organic farms, soilborne diseases need not be a problem. Several studies in which disease severity was compared in organic and conventional farming systems (or with soils from those systems) showed that root diseases are generally less severe in organically than conventionally managed soils. The reasons for reduced root disease severity have seldom been investigated, although relationships with nitrogen supply or microbial diversity have sometimes been found. Crop protection in organic farming is generally not directed at controlling particular pathogens or pests but at management of the environment so that plants are able to withstand potential attacks. Resistant cultivars adapted to the local conditions are in demand among organic farmers. However, the main practices that contribute to disease control are long, balanced rotations, organic amendments and reduced tillage, all geared towards maintenance of the soil organic matter content and fertility. Organic farmers can make use of biological control agents and natural toxic compounds in plant extracts. However, these practices are methods of last resort. A P 0 3 0 2 9 I n t e g r a t e d r o o t d i s e a s e m a n a g e me n t i n o r g a n i c f a r m i n g A . H . C . v a n B r u g g e n a n d A. J . T e r m o r s h u i z e n Additional keywords: conventional agriculture, organic agriculture, soil health, soil quality.

All the essential genetic determinants for site-specific integration of corynephage phi AAU2 are contained within a 1,756-bp DNA fragment, carried on the integrative plasmid p5510, and are shown to be functional in Escherichia coli. One open reading frame, ORF4, encoding a protein of 266 amino acids was shown to represent the phi AAU2 integrase. The nucleotide sequence of the phi AAU2 attachment site, attP, and the attB, attL, and attR sequences in the host "Arthrobacter aureus" C70 were determined. Identical nucleotide sequences were shown to be responsible for the integration of p5510 in the chromosomes of Corynebacterium glutamicum, Brevibacterium divaricatum, and B. lactofermentum, and a sequence almost identical to attB was found to be present in these three strains. In contrast to other phage site-specific recombination systems, a plasmid encompassing only int-attP failed to integrate into the host chromosome. This led to the identification of an 800-bp noncoding reg...

Background and Aim: Bartonellosis is an emerging worldwide zoonosis caused by bacteria belonging to the genus Bartonella. Several studies have been conducted on the prevalence of Bartonella infections from animals and humans, including reports from wild and domestic ruminants. However, there has been only one report of Bartonella infection in water buffaloes from the northeastern part of Thailand. Moreover, the seroprevalence of Bartonella spp. in water buffaloes still remains unknown. This study was conducted to explore the prevalence of Bartonella spp. among water buffaloes from South Thailand using molecular and serological techniques.

Materials and Methods: A total of 312 samples (156 blood and 156 sera) of 156 water buffaloes from 29 farms in Phatthalung Province, South Thailand, were collected from January to March 2021. All samples were screened for Bartonella spp. using polymerase chain reaction and indirect immunofluorescence assay.

Results: The seroprevalence of antibodies against three Bartonella spp. was 16.03% (25/156, 95% confidence interval: 10.65-22.74%), and among 25 water buffaloes with seroprevalence, 56%, 20%, and 24% were positive for antibodies against Bartonella henselae, Bartonella vinsonii subspp. berkhoffii, and Bartonella tamiae, respectively. No significant difference was detected among seroprevalence, gender, age, and ectoparasite infestation.

Conclusion: This is the first report of the seroprevalence of antibodies against B. henselae, B. vinsonii subspp. berkhoffii, and B. tamiae in water buffaloes from South Thailand. Further studies are required on the epidemiology of Bartonella infection among water buffaloes, related personnel, and ectoparasites.

Objective: The article aimed to define chemical constituents of Ganoderma Lucidum (GL) and Psidium Gujava (PG) and to compare the preliminary antibacterial activity of GL & PG with Modified Triple Antibiotic Paste (MTAP) and Calcium hydroxide Ca(OH)2. Material and Methods: Gas Chromatography Mass Spectroscopy (GCMS) was used to define the chemical constituents of Ganoderma Lucidum (GL) and Psidium Gujava (PG). The preliminary antimicrobial activity of hot aqueous and ethanolic extract of GL and PG was evaluated by Agar diffusion assay at 75,50,25,10 and 5 µl/ml concentration and diameter of zone of inhibition was measured .The Minimum Inhibitory Concentration (MIC) was measured by serial dilution method at the highest concentration of 100 µg/ml (stock concentration) in

A genetic recombination study of an industrial strain of Streptomyces avermitilis which produces avermectin is described. A genetic map has been constructed by analysis of haploid recombinants and linkage relationships of 16 marker loci. Fifteen avermectin-nonproducing mutants, produced by mutagenesis, were classified into two phenotypically different groups, of which one produced avermectin aglycon and the other was able to convert avermectin aglycon to avermectins. Two different mutants were found to map closely to each other. Strain Markers K297 ... aveA K299 ... aveA K329 ... aveB K1000 .. lysA K1001 .. hisA K1002 .. uraA K1003 .. athA K1004 .. trpA K1005 .. adeA K1011 .. hisD pdxA K1012 .. hisD proA K1013 .. adeA uraA K1018 .. serA argA strA K1019 .. serA cysA strA K1020 .. serA adeA strA K1021 .. serA argA hisD strA K1022 .. serA argA cysA strA K1030 .. metB aveA K1031 .. hisD aveA K1035 .. adeA aveB K1036 .. hisD aveB K1037 .. hisD strA aveB solvent front A2a aglycon Aia aglycon AVM Al A2 Bi B2

Infections caused by multidrug-resistant (MDR) bacteria continue to be a worldwide problem. Multidrug resistance is growing rapidly among Gram-positive and Gram-negative pathogens that cause infection in the nosocomial environment and the general community. Several MDR pathogens especially, Klebsiella pneumoniae, Enterococcus faecium, Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter spp. and Acinetobacter baumannii , known as ESKAPE pathogens cause the main infections within the nosocomial environment. Antibiotics resistance naturally occurs over time but it a slow process. However, the misuse or overuse of antibiotics has accelerated the number of resistant bacteria, which is difficult to eliminate. Despite, there are still possible treatment options available to eliminate these resistant bacteria in recent days, future attention should focus on avoiding further development of resistant pathogens. In this review, we will describe the ESKAPE, some of their antibiotics resistant mechanisms and bacterial species belonging to the ESKAPE group

Intraclonal genome diversity of Pseudomonas aeruginosa was studied in one of the most diverse mosaic regions of the P. aeruginosa chromosome. The ca. 110-kb large hypervariable region located near the lipH gene in two members of the predominant P. aeruginosa clone C, strain C and strain SG17M, was sequenced. In both strains the region consists of an individual strain-specific gene island of 111 (strain C) or 106 (SG17M) open reading frames (ORFs) and of a 7-kb stretch of clone C-specific sequence of 9 ORFs. The gene islands are integrated into conserved tRNA Gly genes and have a bipartite structure. The first part adjacent to the tRNA gene consists of strain-specific ORFs encoding metabolic functions and transporters, the majority of which have homologs of known function in other eubacteria, such as hemophores, cytochrome c biosynthesis, or mercury resistance. The second part is made up mostly of ORFs of yet-unknown function. Forty-seven of these ORFs are mutual homologs with a pairwise amino acid sequence identity of 35 to 88% and are arranged in the same order in the two gene islands. We hypothesize that this novel type of gene island derives from mobile elements which, upon integration, endow the recipient with strain-specific metabolic properties, thus possibly conferring on it a selective advantage in its specific habitat.

Pseudomonas fuscovaginae was first reported as a pathogen of rice causing sheath rot in plants grown at high altitudes. P. fuscovaginae is now considered a broad-host-range plant pathogen causing disease in several economically important plants. We report what is, to our knowledge, the first draft genome sequence of a P. fuscovaginae strain.

Staphylococcus haemolyticus is an opportunistic bacterial pathogen that colonizes human skin and is remarkable for its highly antibiotic-resistant phenotype. We determined the complete genome sequence of S. haemolyticus to better understand its pathogenicity and evolutionary relatedness to the other staphylococcal species. A large proportion of the open reading frames in the genomes of S. haemolyticus, Staphylococcus aureus, and Staphylococcus epidermidis were conserved in their sequence and order on the chromosome. We identified a region of the bacterial chromosome just downstream of the origin of replication that showed little homology among the species but was conserved among strains within a species. This novel region, designated the "oriC environ," likely contributes to the evolution and differentiation of the staphylococcal species, since it was enriched for species-specific nonessential genes that contribute to the biological features of each staphylococcal species. A comparative analysis of the genomes of S. haemolyticus, S. aureus, and S. epidermidis elucidated differences in their biological and genetic characteristics and pathogenic potentials. We identified as many as 82 insertion sequences in the S. haemolyticus chromosome that probably mediated frequent genomic rearrangements, resulting in phenotypic diversification of the strain. Such rearrangements could have brought genomic plasticity to this species and contributed to its acquisition of antibiotic resistance.

Staphylococcus aureus (S. aureus) is a major cause various
infections in humans and animals throughout the world. The increasing
incidence of S. aureus infection, particularly methicillin-resistant
Staphylococcus aureus (MRSA) is complicated by the antibiotic-resistance
phenomenon. Thus, it requires new strategies to prevent wider scale of its
incidence occurring. Preventative methods against infectious diseases
through vaccination can prevent, control and reduce the severity of the
disease process. Various methods have been used in the development of
vaccines to prevent S. aureus infections, but no satisfactory results have
been obtained. Recent studies suggests that multivalent vaccines based on
cell-mediated immunity is expected to provide better protection against
infection. The purpose of this article is to summarize the challenges of S.
aureus infection and the current status of its potential solution with the
development of a multivalent vaccine and to explain the latest approaches
recommended to obtain successful development of S. aureus vaccine by
inducing T-cells CD8+, CD4+ and Th17. Seven MRSA Indonesian origin
isolates from humans and dairy-cattle were used as candidate vaccines as
genotypic characterization had previously been performed (coa, eta, etb,
hla, hlb, cap5, cap8, fnbA, fnbB and mecA). Vaccination can be performed
with live-attenuated or killed-vaccine and could be combined with an
injection of
CD40 monoclonal-antibodies (mAbs) with the aim to induce
cellular-based active immunity (T CD8+, CD4+ and Th17). These isolates
are expected to be safe vaccine candidates with immunogenic-protective
properties based on genetic and antigenic variation to prevent and control
staphylococcal infections in humans and animals.

2000. Fourteen food residues, Escherichia coli O157:H7 and Staphylococcus aureus on stainless steel surfaces were detected using a combined assay with adenylate kinase as a cellular marker and ATP bioluminescence. The limit of sensitivity ranged from 0Á02 to 708 mg for minced meat and broccoli, respectively. Both methods gave the same detection limit (10 5 cfu) for E. coli and Staph. aureus on stainless steel surfaces. The combined adenylate kinase±ATP assay is applicable to monitor the hygiene of work surfaces, especially those prone to contamination by meat and vegetable residues.

Bats are one of the most widely distributed mammals in the world, and they are reservoirs or carriers of several zoonoses. Bats were trapped in 27 geographic locations across Trinidad and Tobago, and following euthanasia, gastrointestinal tracts were aseptically removed. Contents were subjected to bacteriologic analysis to detect Salmonella spp., Escherichia coli, and Campylobacter spp. Isolates of Salmonella were serotyped, and E. coli isolates were screened for O157 strains and antimicrobial sensitivity to eight antimicrobial agents; phenotypic characteristics also were determined. Of 377 tested bats, representing 12 species, four bats (1.1%) were positive for Samonella spp, 49 (13.0%) were positive for E. coli, and no bats were positive for E. coli O157 strain or Campylobacter spp. Isolated serotypes of Salmonella included Rubislaw and Molade, both from Noctilio leporinus, a fish-eating bat, Caracas recovered from Molossus major, and Salmonella Group I from Molossus ater, both insect-eating bats. Of the 49 isolates of E. coli tested, 40 (82%) exhibited resistance to one or more antimicrobial agents, and the prevalence of resistant strains was comparatively high to erythromycin (61%) and streptomycin (27%) but lower to gentamycin (0%) and sulphamethozaxole/trimethoprim (2%).

An esterase activity has been found, both in the cell-free growth medium and on the cell surface of the hydrocarbon-degrading Acinetobacter calcoaceticus RAG-1. The enzyme catalyzed the hydrolysis of acetyl and other acyl groups from triglycerides and aryl and alkyl esters. Emulsan, the extracellular heteropolysaccharide bioemulsifier produced by strain RAG-1, was also a substrate for the enzyme. Gel filtration showed that the cell-free enzyme was released from the cell surface either emulsan free or associated with the bioemulsifier. The partially purified enzyme was found to interact specifically with the esterified fully active emulsan, but not with the deesterified polymer. A role for esterase in emulsan release from the cell surface was indicated when the enzyme was preferentially depleted from the cell surface under conditions in which emulsan was not released. Such cells lost the capacity to release the biopolymer.