Polyhydroxyalkanoate (PHA) biosynthesis from structurally unrelated carbon sources by a newly characterized Bacillus spp

A newly acquired polyhydroxyalkanoate (PHA) producing Bacillus spp. was identified to be a strain of Bacillus cereus using a range of microbiological and molecular techniques. This strain, named B. cereus SPV, was found to be capable of using a wide range of carbon sources including glucose, fructose, sucrose, various fatty acids and gluconate for the production of PHAs, an advantage for the commercial production of the polymers. The media used for the polymer production was novel in the context of the genus Bacillus. The PHA, once produced, was found to remain at a constant maximal concentration, without any degradation, a great advantage for the commercial production of the PHAs. This particular strain of Bacillus spp. was able to synthesize various PHAs with 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV) and 4-hydroxybutyrate (4HB)-like monomer units from structurally unrelated carbon sources such as fructose, sucrose and gluconate. This is the first report of the incorporation of a 4HB related monomer containing PHA by the genus Bacillus and from structurally unrelated carbon sources. The PHAs isolated had molecular weights ranging between (0.4 and 0.8) x 10(6) and low polydispersity index values (M(W)/M(N)) ranging from 2.6 to 3.4.     

Novel laccases of Ganoderma sp. KU-Alk4, regulated by different glucose concentration in alkaline media

Physiological regulation of laccase production from Ganoderma sp. KU-Alk4, isolated in Thailand, was controlled by the initial glucose concentration in liquid culture. Different laccase isozymes were produced using different starting concentrations of glucose. With 1% glucose, two isozymes, KULac 1 and 2 were produced, while with 4% glucose, three different isozymes, KULac 3, 4 and 5, were produced. The KULacs differed in their molecular mass, ranging from 53 to 112 kDa. KULac 2 was a new laccase that had a different N-terminal amino acid sequence from other laccases previously reported. All the isozymes had optimum pH at 3.5 and were stable over the wide range of pH, 3.0–10.0, especially in alkaline pH. It is noteworthy that the activities of the four KULacs with 2,6-dimethoxyphenol were extremely high up to 90°C. They retained 100% of their activities at 60°C for 1 h.     

Polyhydroxyalkanoates in Gram-positive bacteria: insights from the genera <Emphasis Type="Italic">Bacillus</Emphasis> and <Emphasis Type="Italic">Streptomyces</Emphasis>

Gram-positive bacteria, notably Bacillus and Streptomyces, have been used extensively in industry. However, these microorganisms have not yet been exploited for the production of the biodegradable polymers, polyhydroxyalkanoates (PHAs). Although PHAs have many potential applications, the cost of production means that medical applications are currently the main area of use. Gram-negative bacteria, currently the only commercial source of PHAs, have lipopolysaccharides (LPS) which co-purify with the PHAs and cause immunogenic reactions. On the other hand, Gram- positive bacteria lack LPS, a positive feature which justifies intensive investigation into their production of PHAs. This review summarizes currently available knowledge on PHA production by Gram- positive bacteria especially Bacillus and Streptomyces. We hope that this will form the basis of further research into developing either or both as a source of PHAs for medical applications.     

A histopathological report of some epidermal anomalies of Dover sole, Solea solea L., and other flatfish species in coastal waters off south-east England

The gross pathological and histological changes of typical examples of epidermal anomalies of Dover sole, Solea solea L., and other flatfish from the sewage dumping areas of the Thames Estuary and two 'control' areas are described. Five per cent of flatfish showed anomalies including trawl damage abrasions, fin-rot, ulcers, nodules and tumours, lymphocystis and skeletal anomalies. Many of the anomalies suggested a traumatic aetiology and were often chronic. There was no significant difference in disease incidence between the areas sampled, except more evidence of lymphocystis in one of the control areas.     

Synthesis of oligosaccharides by reversal of a fungal β-glucanase

Summary A crude commercial preparation of -glucanase fromPenicillium emersonii was used to synthesise glucose-containing oligosaccharides by condensation reactions in high concentrations of glucose at elevated temperature. Gentiobiose, laminaribiose, cellobiose, isomaltose and trehalose were identified as products. Heterooligosaccharides were produced by enzyme in some mixtures of glucose and an acceptor sugar. High performance ion-exchange chromatography was used to analyse synthetic products.     

Alginate oligosaccharides as enhancers of penicillin production in cultures of penicillium chrysogenum

Oligosaccharide fragments were prepared by partial acid hydrolysis of sodium alginate and consisted of oligomannuronate (OM) and oligoguluronate (OG) blocks. Effects of the OM and OG blocks on penicillin G production by P. chrysogenum were investigated. The oligosaccharides were found to cause significant increases in penicillin G yields. OM blocks at concentrations 10 to 100 mug/mL were used to further evaluate the effects of the oligosaccharides, and were found to enhance the production of penicillin G in shaken flask cultures of P. chrysogenum P2 (high penicillin producer) and NRRL 1951 (low penicillin producer) at the test concentrations. There was an approximately 50% maximum increase in penicillin G yield from biomass in P. chrysogenum P2 cultures and 150% in P. chrysogenum NRRL 1951 cultures, when compared to control cultures without the oligosaccharides. (c) 1997 John Wiley & Sons, Inc.     

Effects of some phenoloxidase inhibitors on chloroplasts and carboxylating enzymes of sugar cane and spinach

Summary A number of additives have been tested for their effects on o-diphenol: O₂ oxidoreductase activity of cane leaves. The most inhibitory compounds were thioglycollate, -mercaptoethanol, polyethylene glycol and bovine serum albumin. Sulphydryl (SH) compounds did not affect rates of photosynthetic CO₂ assimilation when used at concentrations below 10^-2 M. However, in the presence of Mn⁺⁺ ions they contributed to an O₂ consumption which masked photosynthetic O₂ evolution. Addition of SH compounds or of polymers to the grinding media increased rates of enzymic CO₂ assimilation in crude enzyme preparations from cane leaves, but did not affect rates of CO₂ assimilation in similar spinach preparations. Strong reducing agents, copper chelators, low O₂ tension and high pH were effective in reducing phenoloxidase activity, but presented problems in the isolation and assay of chloroplasts. The results are discussed in relation to (a) design of suitable media for preparation of active cane chloroplasts and (b) comparative studies of enzyme levels in plants of various genera.     

The influence of small oligosaccharides on the immune system

In this study, oligosaccharides known to enhance the synthesis of penicillin by Penicillium chrysogenum have been presented to human immune cells and their effect measured. In addition a range of commercially available oligosaccharides have been tested. Results obtained indicate that oligosaccharides with a degree of polymerisation greater than 6 and with a tendency to form helical structures are most effective at influencing the immune system as measured by the production of reactive oxidising species. Laminariheptaose has been shown to increase reactive oxidising species production by up to 25%, whilst mannan-oligosaccharides with a DP of 6 to 7 decrease production by up to 44%. These and other results show that the immune system can recognise subtle differences in oligosaccharides and that these oligosaccharides could potentially be used to modulate the immune response.     

Elicitor effects on reactive oxygen species in liquid cultures of Penicillium chrysogenum

Activity of reactive oxygen species (ROS) was investigated in liquid cultures of Penicillium chrysogenum P2 supplemented with carbohydrates. Oligosaccharides lowered the ROS activity in all samples. The greatest effect occurred when oligosaccharides were added to samples 48 h after inoculation. The ROS decrease in the presence of oligoguluronate, oligomannuronate and mannan oligosaccharides was 18%, 36% and 54%, respectively (ROS levels varied notably with culture age and type of elicitor). The polysaccharides from which the oligosaccharides were derived showed little (5-10%) overall decrease of ROS.     

Histopathology of some fish tumours from British waters, including an olfactory glioma in coalfish, Pottachius virens L.

A selection of neoplasias in feral fish is described. It includes olfactory glioma in coalfish, Pollachius virens L.; nephroblastoma with metastases and polycystic kidneys in crucian carp, Carassius carassius; lymphosarcoma in roach, Rutilus rutilus , and bream, Abramis bratna; and stomato-papilloma in eel, Anguilla anguilla . The olfactory glioma is one of a few recordings of a central nervous system-derived tumour in teleosts. Although nephroblastoma is relatively common in fish, rarely have metastases been observed. The lymphosarcomas in roach and bream have not been recorded before in the British Isles, but now stomato-papillomas in eel appear to be established at a low level.