Polypropylene straw ampoules for the storage of microorganisms in liquid nitrogen

Liquid nitrogen storage systems are widely used for long term preservation of a range of microorganisms. Strains are stored in ampoules immersed in nitrogen or held in its evolving vapour. Immersion storage maximises the storage capacity of a vivostat but imposes limits on the type of ampoule that can be used. It is of vital importance that an ampoule can be sealed to prevent leakage of the nitrogen during storage. Several ampoule types are commercially avaailable but all have a number of disadvantages in use. They are costly, wasteful of space and difficult to seal reliably. An ampoule which can be simply made in the laboratory from polypropylene drinking straws has been described which is cheap, space saving and easy to seal. These ampoules have been in use for ten years without any problems and their use in the storage of over 2000 strains, predominantly fungi, is described. They have no detrimental effect on strain retrieval as shown by recovery rates after protracted storage. Straw ampoules provide a cheap and safe alternative to those ampoules that are commercially available and can be recommended for use in liquid nitrogen storage systems.     

A hydrolytic procedure giving reproducible analytical conditions

A hydrolytic procedure which can be routinely performed in a readily reproducible environment is described. The procedure is useful in that it can be applied to batches of samples, giving a high degree of confidence that similar conditions exist within and among batches. The method makes use of a special polythene capillary leak plug which is fitted in the mouth of ampoules (which were back-filled with nitrogen) prior to their being sealed in the open laboratory. This plug acts as an efficient barrier, for several minutes, to gaseous diffusion, allowing only small amounts of oxygen to enter the ampoule. The method is demonstrated by results from amino acid analyses of acid-hydrolyzed samples of bovine serum albumin.     

A new method for liquid nitrogen storage of phototrophic bacteria under anaerobic conditions

A simple, effective and economical method for the long-term preservation of bacteria in liquid nitrogen under anaerobic conditions is described. As a case example anaerobic photosynthetic bacteria were successfully preserved. Gas tight small screw-cap glass ampoules with butyl rubber septa were used for freezing the specimen anaerobically. During experimental manipulations no anaerobic chamber or glove boxes were required. All teste cultures yielded high recoveries after repeated thawing and during storage. After freezing, survival recoveries of Rhodospirillaceae range from 70–100%, whereas with strict anaerobic strains of Chlorobiaceae and Chromatiaceae a maximum loss of 1–2 log₁₀ counts was observed. No further loss in viability occurred after 1–2 years of storage.The small size of the ampoules and the use of single ampoule for 15–20 repeated retrievals proved economical with respect to storage space and costs.The system is compact and suitable for the preservation of anaerobic phototropic bacteria and other fragile anaerobic microorganisms.     

A moorable,automated plankton sampler

A moorable, automated plankton sampler is described, designed to obtain series of plankton samples over extended time periods in the absence of a surface vessel. The sampler consists of one or more net-containing boxes, a unit for generating as well as measuring water flow through the net boxes, a programmeable control unit, and a frame. Each net box contains several nets on a vinyl strip, used to move the nets from the storage chamber into the fishing position and then into the preservative chamber. Preservation of samples is in a formalin-brine mixture.Net boxes can be added and the number of nets per box changed; the prototype is described with 1 net box with 10 nets. Volume of water to be filtered, time between sample collections, number of net boxes and the number of nets in each box is programmed into the control unit before sampler deployment. Collections made with the sampler are compared with those made with a SCOR net and a pump.     

A vacuum benthos sampler suitable for diverse habitats

The vacuum benthos sampler consists of a vacuum chamber equipped with a collecting net connected to the intake of a 12 volt pump, a battery, and a standpipe. Contents of the standpipe are vacuumed while substrate is removed and washed with the exhaust hose. The vacuum chamber is designed for rapid changing of nets during replicate sampling. This sampler is equally efficient in flowing and standing water. It was more effective than a modified Hess sampler for collecting a large variety of benthos from flowing (ca 0.25–0.75 m/s) riffles. Required operation time is variable, but 93% of invertebrates caught in 10 min were captured in the first 5 min during our tests, and there was a 94% mean recovery of released organisms during 10 min of subsequent operation. Advantages over previous suction samplers include interception of organisms before they pass through a pump, return of outlet water to the standpipe, capability of sampling in shallow (20–30 mm) water, and that it can be carried and operated by one person.     

A quantitative sampler for collecting invertebrates associated with deep submerged vegetation

Only few of the numerous samplers for collecting invertebrate fauna associated with vegetation permit sampling at depths of more than approximately 0.5 m. This paper describes a sampler allowing collection of epifauna from submerged plants at a depth of up to approximately 2 m, growing in varied densities. The sampler is composed of two panels made of duralumin, connected on one side by means of piano-hinges. One of the panels has an opening covered with mesh, and the other is equipped with a cone-shaped net and detachable sample concentrator at its end. The sampler is coupled with a manipulator with a several meter extension for lowering the sampler under water, as well as for its opening, and closing. The initial assessment of the sampler efficiency, verified in beds of Potamogeton perfoliatus, provided similar results as two other, older and commonly used samplers. In comparison with the older devices, the sampler has the advantage of permitting collecting samples from greater depths. It also enables studying both the vertical and horizontal distribution of invertebrates within a plant patch.     

Sample-hold technique for analysis of respiratory gas composition at high breathing frequencies

A gas sampling device is described for continuous monitoring of respiratory gas composition that is applicable to experimental conditions when the breathing frequency is very high (greater than 2 Hz) and the response time of conventional gas analyzers becomes a critical limiting factor. The system utilizes the principle of discontinuous gas collection at any selected point of the respiratory cycle facilitated by ultraspeed piezoelectric valves and includes provision for sample-hold characteristics. Two distinct modes of operation are supported. In phase-locked mode gas sampling is synchronous with breathing frequency. In scanning mode gas collection is asynchronous with breathing frequency. Phase-locked mode may be used for continuous monitoring of end-tidal gas concentrations, whereas scanning mode is intended for assessing the gas concentration profile throughout the respiratory cycle. The system may be applied to steady breathing encountered in mechanical ventilation at high frequency or during quasi-steady breathing observed in panting animals. Combined with a respiratory mass spectrometer, the system has been used for measurement of gas concentrations in alveolar gas mixtures at breathing frequencies ranging from 3 to 30 Hz that were otherwise not amenable to rapid measuring techniques.     

A new sampler for collecting invertebrates in submerged vegetation

A new sampler is described that can rapidly enclose a specific volume of water at a given depth, including submerged macrophytes and associated invertebrates. The sampler is a tong-shaped instrument consisting of two metal rods connected by a flexible joint. At the end of each arm is a metal cylinder (diameter 10 cm); one end of the cylinder has a sharpened edge and the other is equipped with a net. Powerful metal springs force the cylinders together at high speed, and macrophytes are enclosed in the nets. The sampler is suitable for studying vertical and horizontal distribution of invertebrates, even fast-moving taxa, within submerged vegetation. The device causes little disturbance of the vegetation, hence it is also suitable for repeated sampling within mesocosms.     

An efficient and quantitative aquatic benthos sampler for use in diverse habitats with variable flow regimes

A suction sampler designed to minimize sampling error, and quantitatively collect benthic macroinvertebrates from coarse substrata under various flow regimes is described. This sampler uses a 12 V bilge pump (capacity 4400 1 h^–1) to suck animals into a collecting net from substrata disturbed by a single operator. Macroinvertebrates were collected more rapidly by this sampler than by a Surber sampler or a Boulton suction sampler. Sources of sampling error are discussed for all three samplers. The electric pump sampler described here is suitable for sampling habitats where depth and velocity vary spatially and with time.     

CO(2)-controlled sampling of alveolar gas in mechanically ventilated patients.

A newly designed gas-sampling device using end-tidal CO(2) to separate dead space gas from alveolar gas was evaluated in 12 mechanically ventilated patients. For that purpose, CO(2)-controlled sampling was compared with mixed expiratory sampling. Alveolar sampling valves were easily controlled via CO(2) concentration. Concentrations of four volatile substances were determined in the expired and inspired gas. Isoflurane and isoprene, which did not occur in the inspired air, had ratios of end-tidal to mixed expired concentrations of 1.75 and 1.81, respectively. Acetone and pentane, found in both the inspired and expired air, showed ratios of 0.96 and 1.0, respectively. Precision of concentration measurements was between 2.4% (isoprene) and 11.2% (isoflurane); reproducibility (as coefficient of variation) was 5%. Because the only possible source of isoflurane and isoprene in this setting was patients' blood, selective enrichment of alveolar gas was demonstrated. By using the new sampling technique, sensitivity of breath analysis was nearly doubled.     

A sampling device for the invertebrate fauna of aquatic vegetation

SUMMARY. A sampler designed to provide a quantitative estimate of the benthic invertebrates of littoral/sub-littoral zones dominated by Sphagnum moss is described. Data obtained from a small oligotrophic lake at a depth of 1 m using this sampler are presented. Optimum sample size was determined and samples comprising five sampling units were found to be adequate in terms of the number of invertebrate species present and their relative abundance. Similarity of such samples was greater than 90%.     

A modified reaction cartridge for direct protein sequencing on polymeric membranes.

A newly designed reaction vessel implements a vertical cross-flow type reactor with the Applied Biosystems multi-mode reaction cartridge design. This cartridge is designed for sequencing samples on polyvinylidine difluoride-type membranes. The benefits of this design include a reduced reaction chamber volume that results in lower rates of chemical consumption and less risk of sample loss or contamination during sequencing. Visualization of the membrane in the reaction chamber during sequencing facilitates optimization of drying, washing, extraction and transfer times. The cycle modifications described in this report are designed to optimize post-coupling extraction, cleavage and post-cleavage extraction steps during "flow across" conditions for polymeric membranes. Also, efficient washing and drying of membranes allows for a fast cycle time of 30 minutes when using Pulsed Liquid chemistry. Examples of Blott cartridge utility for sequencing polyvinylidine difluoride-bound proteins in the low picomole range are shown by analyzing samples prepared by a two-dimensional purification scheme using the 230A HPEC and sodium dodecyl sulfate polyacrylamide gel electrophoresis.     

The Second International Standard for somatropin (recombinant DNA-derived human growth hormone): preparation and calibration in an international collaborative study.

A preparation of somatropin (recombinant DNA-derived human growth hormone) was prepared as lyophilised ampoules according to WHO procedures for international biological standards. The candidate preparation (98/574) was evaluated in an international collaborative study (16 laboratories, nine countries), with the following aims: (i) to determine the suitability of the preparation to serve as the International Standard for somatropin by studying its performance in the current range of physico-chemical and biological assay methods employed for somatropin; (ii) to assign a content in terms of the existing (first) International Standard for somatropin, using the currently recognised assay procedure (Size Exclusion High Performance Liquid Chromatography, SE HPLC); (iii) to confirm the specific biological activity of the candidate preparation; (iv) to confirm the stability of the candidate preparation. On the basis of the collaborative study WHO agreed that: the preparation in ampoules coded 98/574 is suitable to serve as the next WHO International Standard for somatropin; the preparation in ampoules coded 98/574 should be established as the second International Standard for somatropin, with a defined ampoule content of 1.95 mg total somatropin plus somatropin-related proteins per ampoule; the specific activity of the preparation should be defined as 3.0 IU/mg somatropin.     

The Stone Brusher, a New Sampler for Submerged Epilithic Material in Shallow Streams and Lakes

The Stone Brusher is designed to take qualitative or semi-quantitative samples of material attached to stones at 7–50 cm depth in running or stagnant waters. The epilithic material is dislodged from the stone surface with a rotating brush enclosed in a chamber and the material is drawn up directly into the sample bottle with an air-cylinder. The operator takes a sample quickly and without putting hands into the water. The sampling area is about 28 cm². The sampler is made of plastic, stainless steel and aluminium and weighs 3.1 kg. The equipment is robust and easily handled and it is constructed to meet the demand for standardized sampling for research and environmental monitoring and to improve working conditions for sampling personnel. The equipment allows sampling from bedrock and large stones that cannot be lifted from the bottom and it can be used for reliable sampling also in fast-flowing streams where the dislodged material is easily flushed away. Using Near-Infrared Spectroscopy and diatom analyses, this new sampler is evaluated in comparison to the recognized toothbrush method, which indicates that the Stone Brusher reduces sampling variability compared with the toothbrush method.     

A self-powered portable insect suction sampler and its use to assess the effects of azinphos methyl and endosulfan on blossom beetle populations on oil seed rape

A new portable insect suction sampler, powered by a small petrol engine, is described. It has been in use for three seasons, and examples given of samples taken from oil-seed rape demonstrate that the suction method is more informative than visual counts or sweep-net sampling for assessing blossom beetle populations.     

Experience with the international standardization of the biological activity of the 3d Standard for streptomycin

The activity of the third International Standard of streptomycin was determined to be equal to 755 IU/mg with the use of accurately weighed amounts of streptomycin and 78037 IU with the use of streptomycin ampoules. The Standardization Center of the WHO decided to use the whole content of the ampoule of the Third International Standard of streptomycin, the activity of which is determined to be equal to 78500 IU per an ampoule.     

International collaborative study by in vitro bioassays of the first international standard for porcine inhibin.

A lyophilized preparation of inhibin from porcine ovarian follicular fluid, ampoule code 86/690, was made internationally available as a research standard for in vitro bioassays in 1987. A study involving ten participants in eight countries assessed the stability and suitability of this research standard to serve as an international standard. Each of the participants used in vitro assays, the majority of which depended upon the inhibition of release of follicle-stimulating hormone from dispersed rat anterior pituitary cells. The research standard 86/690 was compared with coded ampoules of 86/690 stored under conditions of accelerated thermal degradation and with inhibins from different species. Intra- and interlaboratory variation for estimates of potency of a coded duplicate ampoule of the research standard provided the basis for comparisons of non-identical inhibins, but the fourfold variability of potency estimates for identical ampoules was such that no conclusions about the differences seen for non-identical inhibins could be made. Predictions of stability from consensus estimates of potency of ampoules that have undergone accelerated thermal degradation indicated that the research standard had satisfactory stability. On the basis of this study, the research standard 86/690 was deemed sufficiently stable and suitable to serve as a standard for in vitro bioassays and was established by the World Health Organization Expert Committee on Biological Standardization as the First International Standard for Porcine Inhibin. The possible presence, in biological extracts (standard or sample), of other bioactive proteins, such as activin and follistatin, complicates the quantitative interpretation of bioassay data. A standard of highly purified human inhibin is now required as a standard for immunoassays used for clinical research purposes; sufficient quantities of recombinant human inhibins have recently been donated for ampouling and evaluation by bio- and immunoassay in the subsequent phase of the standardization of inhibins.     

Breath-by-breath alveolar gas exchange

A method is described for breath-by-breath measurement of alveolar gas exchange corrected for changes of lung gas stores. In practice, the subject inspires from a spirometer, and each expired tidal volume is collected into a rubber bag placed inside a rigid box connected to the same spirometer. During the inspiration following any given expiration the bag is emptied by a vacuum pump. A computer monitors inspiratory and expiratory tidal volumes, drives four solenoid valves allowing appropriate operation of the system, and memorizes end-tidal gas fractions as well as mixed expired gas composition analyzed by mass spectrometer. Thus all variables for calculating alveolar gas exchange, based on the theory developed by Auchincloss et al. (J. Appl. Physiol. 21: 810-818, 1966), are obtained on a single-breath basis. Mean resting and steady-state exercise gas exchange data are equal to those obtained by conventional open-circuit measurements. Breathing rates up to 30 X min-1 can be followed. The breath-to-breath variability of O2 uptake at the alveolar level is less (25-35%) than that measured at the mouth as the difference between the inspired and expired volumes, both at rest and during exercise up to 0.7 of maximum O2 consumption.     

A new transparent handy sampler for collecting water from lakes,rivers and seas

A handy sampler for collecting water from lakes, rivers and seas is described. The sampler consists of an exchangeable sample tube and a new sample-holding system. The system comprises an upper disk, a lower disk, a pair of arms with a guide pin and a semicircular arm guide with a groove. The water sample collected into the acryl tube is held without flow by a tight tube-closing system. Contamination of the sample by chemical and biological materials from the sample tube is minimized by exchanging the tube with a clean one at each sampling station. This new sampler is light, simple and useful for sampling of water from surface to bottom.     

A modified one-metre Friedinger sampler

SUMMARY. A 1-m water sampler is described together with results obtained from sampling a vertically stratified phytoplankton population of Ceratium hirundinella . These results were analysed using a one-way analysis of variance to partition the total variance into two components. Population estimates from 1-m sections taken sequentially from the surface waters to 5-m depth and integrated, were not significantly different ( P > 0.05) from those obtained using a 5-m vertical tube sampler: replicate sampling units taken with both samplers showed that Ceratium was contagiouly distributed in the vertical water column.