Pseudomonas hydrophila

Initial Discoveries. Xylose isomerase activity was initially found in 1953 in extracts of Lactobacillus pentosus (14), followed by similar activities in extracts of Pseudomonas hydrophila and Pasteurella pestis in the mid-1950s (15-17). An enzyme activity that was found to convert glucose to fructose was discovered in 1957 (18). This activity, found in sonicated extracts from Pseudomonas hydrophila, was enhanced in the presence of... 

The conversion of D-glucose (17) into D-fructose (9) by a microbial enzyme (Scheme 5) was first reported in 1957 when Marshall and Kooi found glucose isomerase activity in cell-free extracts of Pseudomonas hydrophila (91. This enzymatic activity was enhanced in the presence of arsenate. Soon thereafter, other arsenate-requiring enzymes were isolated from Aerobacter sp. as well as Escherichia freundii [10]. Enzymes required arsenate when D-glucose or D-fructose was the substrate but not when the corresponding 6-phosphates 11 and 12 were offered. Purification of the arsenate-dependent principle component from Escherichia intermedia allowed the conclusion that the enzyme was a glucose 6-phosphate isomerase (EC 5.3.1.9) that was able to isomerise free D-glucose when it was complexed with arsenate [11]. 

H 0 A-butanoyl-L-homoserine lactone, BHL or C4-HSL Aeromomas hydrophila Aeromonas salmonicida Pseudomonas aeruginosa, Serratia liquefaciens Extracellular protease, biofilm formation. Extracellular protease. Virulence factors - alkaline protease, cyanide, elastase, haemolysin, lectins, pyocyanin, rhaminolipid, RpoS Swarming, protease. 

Investigations of pure cultures of bacteria clearly show the existence of a threshold concentration for the carbon source below which replication does not occur. This value is about 18 pg/1 for Escherichia coli and Pseudomonas sp. growing on glucose, 180 pg/1 for Aeromonas hydrophila growing on starch,... 

PHA is produced by different bacterial strains. One of the most studied strain is C. necator (formerly known as Wautersia eutropha, Ralstonia eutropha or Alcaligene eutrophus). It was used in industrial production by Imperial Chemical Industries (ICI PLC) to produce P(3HB-co-3HV) under the trade name of BiopoF. The Biopol patents have now been acquired by Metabolix Inc. (USA) (Verlinden et al. 2007). Until now, C. necator is still being used widely for bacterial fermentation as it is an efficient strain. Other important strains that have been studied for PHA production are Bacillus spp., Alcaligenes spp.. Pseudomonas spp., Aeromonas hydrophila, Rhodopseudomonas palustris, recombinant Escherichia coli, Burkholderia sacchari, and Halomonas boliviensis (Verlinden et al. 2007). 

C. necator is the model bacterium for the biosynthesis of PHA. This strain generally initiates the synthesis of PHA when either nitrogen or phosphorous is limited during growth (Kahar et al. 2004). A similar phenomenon occurs in several other PHA producers including Burkholderia cepacia (Zazali and Tan 2005 Mitomo et al. 1999), Pseudomonas sp. (Choi et al. 2003), and A. hydrophila... 

So far, biosynthesis of PHA can be summarized in eight pathways (Fig. 4, Table 1). The first pathway involves the three key enzymes (3-ketothiolase, NADPH-dependent acetoacetyl-CoA reductase, and PHA synthase encoded by genes phaA, phaB, and phaC, respectively. Ralstonia eutropha is the representative of this pathway. An associated pathway involving PHA degradation catalyzed by PHA depolymerase, dimer hydrolase, 3-hydroxybutyrate dehydrogenase, and acetoacetyl-CoA synthase helps regulate PHA synthesis and degradation. The associated pathway was found in strains of Aeromonas hydrophila. Pseudomonas stutzeri, R. eutropha, and Pseudomonas oleovorans (Sudesh et al. 2000). 

The second PHA synthesis pathway (pathway II) is related to fatty acid uptake by microorganisms. After fatty acid P-oxidation, acyl-CoA enters the PHA monomer synthesis process. Enzymes including 3-ketoacyl-CoA reductase, epimerase, (I )-enoyI-CoA hydratase/enoyl-CoA hydratase I, acyl-CoA oxidase (putative), and enoyl-CoA hydratase I (putative) were found to be involved in supplying the PHA precursor 3-hydroxyacyl-CoA for PHA synthesis. Pseudomonas putida, Pesudomonas aeruginosa, and A. hydrophila are able to use pathway n to synthesize medium-chain-length (mcl) PHA or copolymers of (/ )-3-hydroxybutyrate (R3HB) and (R)-3-hydroxyhexanoate (PHBHHx). 

Zhao W, Chen GQ (2007) Production and Characterization of terpolyester poly(3-hydroxybu-tyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) by recombinant Aeromonas hydrophila 4AK4 harboring genes phaAB. Process Biochem 42 1342-1347 Zheng LZ, Li Z, Tian HL, Li M, Chen GQ (2005) Molecular cloning and functional analysis of (R)-3-hydroxyacyl-acyl carrier protein coenzyme A transacylase from Pseudomonas mendocina LZ. FEMS Microbiol Lett 252 299-307... 

Documented effects Alcohol and water extracts of the roots inhibited the growth of Aeromoms hydrophila. Bacillus mega-terium, Corynebacterium xenosis, Pseudomonas aeruginosa. Micrococcus luteus. Enterococcus faecalis, and Staphylococcus aureus, but was not an effective inhibitor of Escherichia coli (Golcu et al. 2002). In experiments with rats that ate fresh roots decreased bladder and kidney stone formation was observed, but increased death rates were exhibited. In experiments with rabbits that were given root extracts orally, decreased calcium oxalate crystal formation in the kidneys and hepatotoxicity was observed. Genotoxic effects were observed in bacterial and mammalian cell systems (Blumenthal 1998). 

Acetone, diethyl ether, and ethanol extracts of the lichen Cetraria aculeata for their antimicrobial activity have been evaluated. The extracts were found active against Escherichia coli. Staphylococcus aureus, Aeromonas hydrophila, Proteus vulgaris. Streptococcus faecalis, Bacillus cereus. Bacillus subtilis. Pseudomonas aeruginosa, and Listeria monocytogenes. However, no antimicrobial activity against the fungi was detected (Tiirk et al. 2003). The lichen extract almost... 

Acinetobacter calcoaceticuS) Pseudomonas fluorescens, Aeromonas hydrophila. 

---