Purification of allantoinase from soybean seeds and production and characterization of anti-allantoinase antibodies.

Allantoinase catalyzes the hydrolysis of allantoin to allantoic acid, a reaction important in both biogenesis and degradation of ureides. Ureide production in cotyledons of germinating soybean (Glycine max L.) seeds has not been studied extensively but may be important in mobilizing nitrogen reserves. Allantoinase was purified approximately 2500-fold from a crude extract of soybean seeds by differential centrifugation, heat treatment, ammonium sulfate fractionation, ethanol fractionation, and fast protein liquid chromatography (Pharmacia) with Mono-Q and Superose columns. The purified enzyme had a subunit size of 30 kD. Polyclonal antibodies produced against the purified protein titrated allantoinase activity in a crude extract of seed proteins. Antibodies recognized the 30-kD band in western blot analysis of crude seed extracts, indicating that they were specific for allantoinase.     

Aspects of cold hardiness in Steganacarus magnus (Acari: Cryptostigmata)

Supercooling points and the presence of antifreeze compounds were measured for both nymphs and adults of Steganacarus magnus (Nicolet) collected from a coniferous forest soil in southern England in March, June and November. The mean supercooling point of nymphs was –14.4°C and of adults, –11.7°C. Acclimation to low temperatures (1–2°C) did not alter these values significantly. The total concentration of antifreeze compounds in the nymphs was 4.46 g mg^-1 and in the adults 0.91 g mg^-1. These results are compared with similar data for other species of cryptostigmatic mites.     

Biology and life cycle ofAtelocauda koae,an unusual demicyclic rust

Atelocauda koae, a rust of the native HawaiianAcacia koa, is considered as a demicyclic species, having spermogonial, aecial, and telial states, but is unusual in production of aeciospores simultaneously with teliospores rather than consecutively. Host inoculation with spores of each state separately confirmed that the life cycle was perpetuated by the telial state, but the aeciospores, while capable of germination and stomal penetration, did not produce detectable infection. This rust therefore behaves as a microcyclic species, and appears to be in evolutionary transition toward this reduced state. Teliospores produced vestigial, permanently attached basidiosopores which germinated to produce infective hyphae. The hyphae entered the host either through stomata or penetrated the epidermis directly, with the latter method being more common. Unusual nuclear associated with teliospore germination, in which meiosis occurs in more than one diploid nucleus was observed, in confirmation of an earlier study.     

Molecular dynamics of alamethicin transmembrane channels from open-channel current noise analysis.

Conductance noise measurement of the open states of alamethicin transmembrane channels reveals excess noise attributable to cooperative low-frequency molecular dynamics that can generate fluctuations approximately 1 A rms in the effective channel pore radius. Single-channel currents through both persistent and nonpersistent channels with multiple conductance states formed by purified polypeptide alamethicin in artificial phospholipid bilayers isolated onto micropipettes with gigaohm seals were recorded using a voltage-clamp technique with low background noise (rms noise < 3 pA up to 20 kHz). Current noise power spectra between 100 Hz and 20 kHz of each open channel state showed little frequency dependence. Noise from undetected conductance state transitions was insignificant. Johnson and shot noises were evaluated. Current noise caused by electrolyte concentration fluctuation via diffusion was isolated by its dependence on buffer concentration. After removing these contributions, significant current noise remains in all persistent channel states and increases in higher conductance states. In nonpersistent channels, remaining noise occurs primarily in the lowest two states. These fluctuations of channel conductance are attributed to thermal oscillations of the channel molecular conformation and are modeled as a Langevin translational oscillation of alamethicin molecules moving radially from the channel pore, damped mostly by lipid bilayer viscosity.     

Evaporative water loss in two sympatric species of vespertilionid bat, Plecotus auritus and Myotis daubentoni: relation to foraging mode and implications for roost site selection

Simultaneous measures of oxygen consumption and evaporative water loss (EWL) were made in two species of temperate-zone vespertilionid bat ( Plecotus auritus and Myotis daubentoni ; mean body mass 9.12 and 10.12g, respectively) at ambient temperatures (T_a) of 5, 15 and 25°C and variable vapour pressure deficit. EWL was directly dependent on vapour pressure deficit and oxygen consumption and inversely dependent on T_a. EWL was significantly greater in P. auritus than in M. daubentoni. A model for EWL in P. auritus under a variety of environmental conditions (5–25°C and 20–80% relative humidity) suggested that EWL from bats in shallow summer torpor will be lowest at low T_a, and that, except at low (> 50%) relative humidity, EWL from euthermic bats will be lowest at high T_a. At low relative humidity (< 20%), resting bats could lose over 30% of body mass per day (24 h) through evaporation. At high T_a (> 25°C), EWL from euthermic bats could be over 65% lower at high (> 80%) compared to low (< 20%) relative humidity. In bats in shallow summer torpor at low (5°C) T_a the equivalent saving was > 96%. At low relative humidity predicted EWL from bats in shallow summer torpor was 34 to 81% of that from euthermic bats, and at low T_a and high relative humidity was only 2%. In the wild, M. daubentoni has freer access to drinking water than does P. auritus and yet EWL at rest was higher in the latter species. We suggest that post-prandial dumping of urinary water by M. daubentoni leads to a limit in the amount of body water available to this species to cover evaporative losses once within the day roost, which in turn has led to an adaptation of physiology towards the minimization of EWL when at rest.     

Increased yields of Rhizobium japonicum by an extract of the green alga,Scenedesmus obliquus (276-3a)

Summary The effects of algal extract (AE) and yeast extract (YE) on the growth of Rhizobium japonicum were studied. YE concentrations above 0,1% inhibited growth. Increased concentrations of AE in growth medium increased bacterial yield up to an extract concentration of 1%. At 1% AE concentration maximum yields were achieved which were 3 times greater than those achieved with YE.     

Relationship between the transport from isolated nuclei of two abundant cytoplasmic messengers and the source of a messenger RNA transport factor

Messenger RNA transport from isolated nuclei requires a 35×10³ dalton cytoplasmic protein(s) which is present in both the cytosol and polyribosome fractions. Recombinant DNA probes containing cDNA inserts were used to quantitate the transport of rat liver-specific albumin and male rat liver-specific ₂U-globulin messenger RNA (mRNA) from male rat liver nuclei in response to the mRNA transport factors from homologous and heterologous tissues. No mRNA transport occurs in the absence of the transport factor(s). Both messengers are transported proportionately in response to the factor(s) from male or female rat liver cytosol, or from the polyribosomes (messenger ribonucleoprotein) of male or female rat liver, or brain. The transport factor(s) do not, therefore, appear to differentiate between the coding sequences of two unrelated hepatic messenger RNA's.     

Cytomat-R: a computer-controlled multiple laser source multiparameter flow cytophotometer system.

A multiple illumination wavelength multiparameter flow cytophotometer system, using laser sources and controlled by a small, general-purpose digital computer, has been produced for use in the development of new flow cytometric techniques. Three different laser wave-lengths can be used simultaneously to illuminate different regions of the flow chamber; as many as five measurements of light scattering at various angles, extinction, and fluorescence at one or more wavelengths can be made at each illuminated station. Cells in suspension may be examined at rates of 1000 cells/sec, with seven correlated optical measurements being recorded for each cell. A library of programs for data manipulation and statistical analysis make it possible to use the system to develop and implement cell characterization, counting and classification procedures for basic and clinical research applications.