State of Lake Sysmäjärvi,Eastern Finland,after loading with mine water and municipal waste water for several decades

Hydrobiologia - The deep mining of copper and nickel at Outokumpu, Eastern Finland, lasted from 1910 to the late 1980s, during which period metalliferous waste water of high conductivity and...     

Rapid production of thermostable cellulase-free xylanase by a strain of Bacillus subtilis and its properties

A Bacillus subtilis strain isolated from a hot-spring was shown to produce xylanolytic enzymes. Their associative/synergistic effect was studied using a culture medium with oat spelts xylan as xylanase inducer. Optimal xylanase production of about 12 U ml⁻¹ was achieved at pH 6.0 and 50°C, within 18 h fermentation. At 50°C, xylanase productivity obtained after 11 h in shake-flasks, 96,000 U l⁻¹ h⁻¹, and in reactor, 104,000 U l⁻¹ h⁻¹ was similar. Increasing temperature to 55°C a higher productivity was obtained in the batch reactor 45,000 U l⁻¹ h⁻¹, compared to shake-flask fermentations, 12,000 U l⁻¹ h⁻¹. Optimal xylanolytic activity was reached at 60°C on phosphate buffer, at pH 6.0. The xylanase is thermostable, presenting full stability at 60°C during 3 h. Further increase in the temperature caused a correspondent decrease in the residual activity. At 90°C, 20% relative activity remains after 14 min. Under optimised fermentation conditions, no cellulolytic activity was detected on the extract. Protein disulphide reducing agents, such as DTT, enhanced xylanolytic activity about 2.5-fold. When is used xylan as substrate, xylanase production decreased as function of time in contrast, with trehalose as carbon source, xylanase production in maintained constant for at least 80 h fermentation.     

Survival of freeze-dried Lactobacillus plantarum and Lactobacillus rhamnosus during storage in the presence of protectants

No significant differences were observed in the viability of Lactobacillus plantarum and Lactobacillus rhamnosus cells during freeze-drying in the presence or absence of inositol, sorbitol, fructose, trehalose, monosodium glutamate and propyl gallate. However, survival was higher during storage when drying took place in the presence of these compounds. Sorbitol produced more significant effects than the other compounds toward maintaining viability of freeze-dried L. plantarum and L. rhamnosus.     

Hydrogenases and Hydrogen Metabolism of Cyanobacteria

Cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupSL) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxFUYH) which has the capacity to both take up and produce hydrogen. This review summarizes our knowledge about cyanobacterial hydrogenases, focusing on recent progress since the first molecular information was published in 1995. It presents the molecular knowledge about cyanobacterial hupSL and hoxFUYH, their corresponding gene products, and their accessory genes before finishing with an applied aspect—the use of cyanobacteria in a biological, renewable production of the future energy carrier molecular hydrogen. In addition to scientific publications, information from three cyanobacterial genomes, the unicellular Synechocystis strain PCC 6803 and the filamentous heterocystous Anabaena strain PCC 7120 and Nostoc punctiforme (PCC 73102/ATCC 29133) is included.     

Agrobacterium tumefaciens-mediated transformation to alter ethylene and cytokinin biosynthesis in broccoli

Broccoli (Brassica oleracea var. italica) deteriorates rapidly following harvest. Postharvest treatment of broccoli with 6-benzylaminopurine delays senescence, whilst exogenous ethylene has been shown to accelerate this process following harvest. To alter ethylene biosynthesis, broccoli was transformed, using Agrobacterium tumefaciens-mediated transformation, with an antisense ACC oxidase gene from broccoli driven by the asparagine synthetase promoter from asparagus. In addition, broccoli was transformed with the chimeric gene construct SAG12-IPT to alter cytokinin biosynthesis during harvest-induced senescence. Transformation was achieved using both hypocotyl and cotyledonary petiole explants. The presence of an antisense ACC oxidase gene enhanced transformation efficiency, but Ag⁺ incorporated into the medium did not. The transgenic nature of these plants was confirmed by PCR and Southern analyses.     

Kryptoperidinium foliaceum blooms in South Carolina: a multi-analytical approach to identification

Observations following the discovery of Kryptoperidinium foliaceum blooms in South Carolina (SC), USA, suggest that a multi-analytical approach, using a standard, minimal set of criteria, should be adopted for determining dinoflagellate species identity and taxonomic placement. A combination of morphological, molecular, and biochemical analyses were used to determine the identity of this “red tide” dinoflagellate, first documented in SC waters in the spring of 1998. Results from thecal plate tabulations (based on scanning electron and epifluorescence microscopy), gene sequence data, species-specific PCR probe assays, and microalgal pigment profiles were analyzed and compared to reference cultures of K. foliaceum. Comparative data showed marked inconsistencies among the K. foliaceum reference culture isolates. In addition, the SC bloom isolate was shown to be mononucleate, contrary to previous reports for K. foliaceum, suggesting a more transient endosymbiotic association than previously considered.     

Effectiveness of appropriately trained nurses in preoperative assessment: randomised controlled equivalence/non-inferiority trial

ObjectiveTo determine whether preoperative assessments carried out by appropriately trained nurses are inferior in quality to those carried out by preregistration house officers.DesignRandomised controlled equivalence/non-inferiority trial.SettingFour NHS hospitals in three trusts. Three of the four were teaching hospitals.ParticipantsAll patients attending for assessment before general anaesthesia for general, vascular, urological, or breast surgery between April 1998 and March 1999.InterventionAssessment by one of three appropriately trained nurses or by one of several preregistration house officers.Results1907 patients were randomised, and 1874 completed the study; 926 were assessed by house officers and 948 by nurses. Overall 121/948 (13%) assessments carried out by nurses were judged to have possibly affected management compared with 138/926 (15%) of those performed by house officers. Nurses were judged to be non-inferior to house officers in assessment, although there was variation among them in terms of the quality of history taking. The house officers ordered considerably more unnecessary tests than the nurses (218/926 (24%) v 129/948 (14%).ConclusionsThere is no reason to inhibit the development of nurse led preoperative assessment provided that the nurses involved receive adequate training. However, house officers will continue to require experience in preoperative assessment.     

One hundred years ago: Presents from patient

ObjectiveTo compare rates of upper gastrointestinal haemorrhage among elderly patients given selective cyclo-oxygenase-2 (COX 2) inhibitors and non-selective non-steroidal anti-inflammatory drugs (NSAIDs).DesignObservational cohort study.SettingAdministrative data from Ontario, Canada, used from 17 April 2000 to 31 March 2001 to identify population based, NSAID-naive cohorts of patients.PatientsSubjects aged ⩾66 years who started taking non-selective NSAIDs (n=5391), diclofenac plus misoprostol (n=5087), rofecoxib (n=14 583), or celecoxib (n=18 908) and a randomly selected control cohort not exposed to NSAIDs (n=100 000).ResultsRelative to controls, the multivariate model revealed an increased short term risk of upper gastrointestinal haemorrhage for users of non-selective NSAIDs (adjusted rate ratio 4.0 (95% confidence intervals 2.3 to 6.9)), diclofenac plus misoprostol (3.0 (1.7 to 5.6)), and rofecoxib (1.9 (1.3 to 2.8)) but not celecoxib (1.0 (0.7 to 1.6)). Relative to celecoxib, significantly higher risks of upper gastrointestinal haemorrhage were observed for non-selective NSAIDs (4.4 (2.3 to 8.5)), diclofenac plus misoprostol (3.2 (1.6 to 6.5)), and rofecoxib (1.9 (1.2 to 2.8)). Relative to rofecoxib, non-selective NSAID users were at significantly higher risk of upper gastrointestinal haemorrhage (1.9 (1.0 to 3.5)).ConclusionsThis population based observational study found a lower short term risk of upper gastrointestinal haemorrhage for selective COX-2 inhibitors compared with non-selective NSAIDs.

What is already known on this topic

Long term NSAID use is associated with the development of peptic and duodenal ulcersSelective COX 2 inhibitors are claimed to cause fewer gastrointestinal problems than conventional, non-selective NSAIDsIt is unclear to what degree COX 2 inhibitors increase gastrointestinal risk relative to not using NSAIDs, and the relative gastrointestinal safety of the different COX 2 inhibitors is uncertain

What this study adds

The risk of upper gastrointestinal haemorrhage with the COX 2 inhibitors rofecoxib and celecoxib was significantly lower than with conventional NSAIDs, but the risk with rofecoxib was significantly higher than that with celecoxibThe risk of gastrointestinal haemorrhage with celecoxib was similar to that in controls not using NSAIDs