Optimum temperature for egg development of phenotypes in Haemonchus contortus cayugensis as determined by Arrhenius diagrams and Sacher's entropy function

Lejambre L. P. and Whitlock J. H. 1973. Optimum temperature for egg development of phenotypes in Haemonchus contortus cayugensis as determined by Arrhenius diagrams and Sacher's entropy function. International Journal for Parasitology3: 299–310. Oxygen uptake, maturation time and percentage hatch were determined on eggs from “wild-type” Haemonchus contortus cayugensis populations as well as those from the morph types smooth, linguiform B and linguiform A. Sacher's organizational entropy, which is essentially a sum of oxygen utilized by a system corrected for the number of viable units in the system, was used to determine the optimum temperature for development of the eggs. Although the eggs from “wild-type” H. contortus cayugensis hatched well across a broad temperature range; individual phenotypes showed a much narrower range. The optimum temperature for the development of eggs from smooth worms was approximately 30°C while linguiform A and B hatched best at 25°C. Linguiform A eggs had a broader temperature tolerance than linguiform B so that at temperatures of 17°C they hatched with a greater efficiency than did either smooth or linguiform B. It is argued that H. contortus follows a “strategy” of having many phenotypes, each one of which appears to be adapted to a different temperature. This would allow a population to maintain a broad range of optimal temperatures without the expense of maintaining the cybernetic machinery which a single individual would have to have if it were to tolerate the same range of temperature.     

Effect of Bilirubin on the Arrhenius Plots for Na, K-ATPase Activities of Young and Adult Rat Cerebra

The effect of bilirubin on the temperature dependence of Na,K-ATPase activity was investigated with NaI-treated microsomes prepared from young (13- to 23-day-old) and adult (about 1-year-old) rat cerebra. The Arrhenius plots for the enzymic activities in the young and adult rats showed break temperatures at 26 and 18 degrees C, respectively. In the young rat enzyme, bilirubin caused a shift of the break temperature to 23 and 22 degrees C at concentrations of 60 and 120 microM, respectively, with a significant increase of the activation energy below the break temperature. However, no significant changes in the break temperature and the activation energy were observed in the adult rat enzyme exposed to the same concentrations of the pigment. The results suggest that the lipid environment surrounding the enzyme and modulating its activity in the plasma membranes may differ between the young and adult rat cerebra, and that bilirubin may change the physical state of the lipids related to the activity of the young rat Na,K-ATPase.     

Using maximum heart rate as a rapid screening tool to determine optimum temperature for aerobic scope in Pacific salmon Oncorhynchus spp

The mean ±s.e. optimum temperature (T(opt)) for aerobic scope in juvenile coho salmon Oncorhynchus kisutch was determined to be 17·0 ± 0·7° C. The repeated measures protocol took 3 weeks to complete the T(opt) determination using 12 fish tested at five temperatures separated by 2° C increments. This experiment also demonstrated that the T(opt) was associated with maximum heart rate (f(H)) failing to maintain a Q(10) -related increase with temperature. When maximum f(H) was produced in anaesthetized fish with pharmacological stimulation and f(H) measured from electrocardiogram recordings during acute warming, the Arrhenius break temperature (ABT) for Q(10) discontinuities in maximum f(H) (mean ±s.e. = 17·1 ± 0·5° C for 15 ppm clove oil and 16·5 ± 0·2° C for 50 ppm MS-222) was statistically indistinguishable from the T(opt) measured using aerobic scope. Such a determination took only 3 days rather than 3 weeks. Therefore, it is proposed that determining ABT for discontinuities in maximum f(H) in anaesthetized fish presents itself as a valuable, high-throughput screening tool to assess T(opt) in fishes, a metric that has become recognized as being extremely valuable in fish biology and fisheries management.     

Arrhenius plots and the involvement of thermotropic phase transitions of the thylakoid membrane in chilling impairment of photosynthesis in thermophilic higher plants

Abstract Breaks and discontinuities in Arrhenius plots of physiological and physical properties of thylakoids are not diagnostic of thermotropic lipid phase transitions of the membrane. Bulk lipid transitions, as first inferred by the membrane phase transition hypothesis, do not occur in any higher plant at chilling temperatures. Solidification of some varying, but always minor, fraction of the total membrane lipid does take place. However, the presence of minor domains of solid thylakoid membrane lipid at chilling temperatures is not unique to chilling sensitive plants but is also found in tolerant species. Minor solidification may in some plants, or groups of plants, be controlled by the specific molecular species of phosphatidylglycerol only recently investigated. In plants containing little, or no, phosphatidylglycerol with this positional distribution of fatty acids, other yet unknown constituents of the membrane must fill a similar function, since DSC thermograms indicate minor solidification also in isolated, unperturbed thylakoids from chilling tolerant species. However, chilling induced phase transitions, or other perturbations, of the thylakoid membrane are not the reason for the chilling lability of net photosynthesis in the intact plant. This conclusion follows from detailed comparison between photosynthetic membranes isolated from prechilled plants and the effects of chilling exposure on CO₂ fixation of the whole plant. Damage at the level of the thylakoid membrane does occur, although not to the extent where it can account for the proportionally much larger damage to CO₂ fixation.     

High-resolution profiles of temperature and dissolved oxygen in a river

Longitudinal profiles of water quality along a well-mixed tidal river are, ideally, based on simultaneous measurements at fixed stations distributed along the river. The resolution of the profiles is limited by the density of the stations. However, for a given number of stations the resolution is greatly increased if water quality date can be extrapolated upstream and downstream of the stations, making use of velocity data; the resolution is then determined by the density of the extrapolated data points, which may be an order of magnitude higher than the density of the stations. A 15-km length of river was investigated using 5 current meters equipped to measure depth, temperature, conductivity and dissolved oxygen. Data were recorded simultaneously every 10 minutes. When the average cross-sectional speed was 0.25 ms⁻¹ (typical of tidal conditions), the extrapolated data points were 150 m apart, so the resolution of the resulting profiles (7 per kilometre) was much higher than that of the stations alone (0.3 per kilometre). The extrapolation process required a means of deducing the average cross-sectional speed from the speed measured at a given station. The key to this was provided by temperature data recorded during the onset of a spate, when tidal flow was suspended and the average cross-sectional speed was uniformly about 0.75 ms ⁻¹ at four of the stations. Profiles of temperature and dissolved oxygen were generated by this method; the resolution was about 2 data points km⁻¹ during the onset of the spate, and 6 points km⁻¹ during tidal flow.     

Role of proteins and lipids in non-linear Arrhenius plots of Drosophila mitochondrial succinate-cytochrome c reductase studied by rebinding experiments

Abrupt changes in the Arrhenius activation energy of membrane-bound enzymes have often been correlated with changes in the physical state of membrane phospholipids. Similar changes in activation energy have also been found in soluble enzymes. The possibility exists, therefore, that in some of the membrane-bound enzymes the changes might reflect intrinsic changes of the proteins independent of changes in the membrane phospholipids. This hypothesis was investigated using Drosophila mitochondria isolated from wild type and the mutant Ocd^ts-1. In this mutant it has been shown that succinate-cytochrome $\text{c}$ reductase exhibits a change in Arrhenius activation energy at 18°C which is not found in the wild type (Sondergaard, L., Nielsen, N.C. and Smillie, R.M. (1975) FEBS lett. 50, 126–129). A quantitative thin-layer chromatographic analysis of mitochondrial phospholipids showed sphingomyelin to be more abundant in the wild type than in the mutant (5.2% and 4.3% of the total phospholipids, respectively). Since it was shown that the succinate-cytochrome $\text{c}$ reductase had a lipid requirement for full activity, reciprocal rebinding experiments were done. These experiments showed that the reconstituted membranes exhibited the change in activation energy at 18°C only when the protein moiety came from mutant mitochondria, that is, the change was independent of the source of the phospholipids used.     

Interaction of phospholipid dispersions with water-soluble porphyrins as monitored by their Raman temperature profiles

Raman scattering spectra of 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) dispersions, mixed with water-soluble porphyrins, i.e. cationic copper(II)-5,10,15,12-tetrakis(4-N-methylpyridyl) and anionic silver(II)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrins, were measured in the 2800-3100 cm(-1) C-H stretching vibration region as a function of the temperature within the 5-55 degrees C range. Temperature profiles of Raman data were constructed from a quantitative data treatment based on factor analysis. This method is shown to be more efficient than the commonly used approach employing peak intensity ratios. Parameters of the gel phase to liquid crystal phase transition determined from Raman temperature profiles were used to monitor the porphyrin influence on DPPG and DPPC structures. Both negatively and positively charged porphyrins significantly perturb DPPC and DPPG dispersions, causing significant downshift of the transition temperature and broadening of the transition region. Water-soluble porphyrins are assumed to set at the outside part of phospholipid dispersions and interact via coulombic forces with charged lipid heads. For the cationic CuTMPyP, the strongest effect has been observed for negatively charged DPPG. In contrast, anionic AgTPPC4 has been found to interact more efficiently with DPPC possessing both positive and negative charges.     

A photoacoustic method for rapid assessment of temperature effects on photosynthesis

The photosynthetic and photoacoustic properties of leaf samples were studied using a photoacoustic system modified for precise temperature control. Data were collected over a temperature range of −10 °C to +60 °C. A distinct acoustic noise transient marked the freezing temperature of the samples. A positive absorption transient and a brief period of oxygen uptake marked the thermal denaturing temperature of the samples. Between these extremes, the effects of temperature on light absorption, oxygen evolution, and photochemical energy storage were quantified quickly and easily. Oxygen evolution could be measured as low as −5 °C and showed a broad temperature peak that was 10 °C lower under limiting light intensity than under saturating light intensity. Photochemical energy storage showed a narrower temperature peak that was only slightly lower for limiting light intensities than for saturating light intensities. In a survey of diverse plants, temperature response curves for oxygen evolution were determined readily for a variety of leaf types, including ferns and conifer needles. These results demonstrate that temperature-controlled photoacoustics can be useful for rapid assessment of temperature effects on photosynthesis and other leaf properties.     

Determination of melting temperature and temperature melting range for DNA with multi-peak differential melting curves

Many factors that change the temperature position and interval of the DNA helix–coil transition often also alter the shape of multi-peak differential melting curves (DMCs). For DNAs with a multi-peak DMC, there is no agreement on the most useful definition for the melting temperature, T_m, and temperature melting width, ΔT, of the entire DNA transition. Changes in T_m and ΔT can reflect unstable variation of the shape of the DMC as well as alterations in DNA thermal stability and heterogeneity. Here, experiments and computer modeling for DNA multi-peak DMCs varying under different factors allowed testing of several methods of defining T_m and ΔT. Indeed, some of the methods give unreasonable “jagged” T_m and ΔT dependences on varying relative concentration of DNA chemical modifications (r_b), [Na⁺], and GC content. At the same time, T_m determined as the helix–coil transition average temperature, and ΔT, which is proportional to the average absolute temperature deviation from this temperature, are suitable to characterize multi-peak DMCs. They give smoothly varying theoretical and experimental dependences of T_m and ΔT on r_b, [Na⁺], and GC content. For multi-peak DMCs, T_m value determined in this way is the closest to the thermodynamic melting temperature (the helix–coil transition enthalpy/entropy ratio).     

A rapid radioimmunoassay for determining plasma concentrations of LH in dogs

A heterologous dog LH radioimmunoassay was modified to provide accurate results for LH concentrations in blood plasma of dogs within 3-4 h. This assay utilizes radioiodinated ovine LH (LER-1056-C2), antiserum against ovine LH (GDN-15) at a final dilution of 1:48,000 and dog LH (LER-1685-1) as standard. A 60-min incubation, including a 30-min delay in the addition of tracer, was carried out at 37 degrees C. The free and antibody-bound hormone were separated by addition of a Micro Sepharose bead suspension containing anti-gamma-globulin, followed by incubation at room temperature for 30 min. The minimum detectable concentration in this assay, calculated from the precision profile, was 1.5 micrograms/l. The amount of dog LH needed to cause 50% reduction of the initial binding was 1.57 +/- 0.13 ng/tube (15.7 micrograms/l for 100-microliters samples). Daily blood samples were collected in heparinized tubes from the cephalic vein of 5 pointer and 7 beagle bitches from the onset of pro-oestrus until 3-4 days after either the last mating or artificial insemination with frozen semen or until metoestrus. Samples were assayed for LH content by the short and normal incubations as well as for progesterone and oestradiol-17 beta content. In all bitches plasma concentrations of progesterone increased rapidly within 1 week after the LH peak which indicates that they had ovulated. Comparison of the short (1.5 h) with the normal (24 h) incubation system resulted in a regression equation: y = 1.0 + 0.7 x (r = 0.95, n = 153 samples).(ABSTRACT TRUNCATED AT 250 WORDS)     

A biosensor platform for rapid detection of E. coli in drinking water

There remains a need for rapid, specific and sensitive assays for the detection of bacterial indicators for water quality monitoring. In this study, a strategy for rapid detection of Escherichia coli in drinking water has been developed. This strategy is based on the use of the substrate 4-methylumbelliferyl-β-d-glucuronide (MUG), which is hydrolyzed rapidly by the action of E. coli β-d-glucuronidase (GUD) enzyme to yield a fluorogenic 4-methylumbelliferone (4-MU) product that can be quantified and related to the number of E. coli cells present in water samples. In this study, the detection time required for the biosensor response ranged between 20 and 120 min, depending on the number of bacteria in the sample. This approach does not need extensive sample processing with a rapid detection capability. The specificity of the MUG substrate was examined in both, pure cultures of non-target bacterial genera such as Klebsiella, Salmonella, Enterobacter and Bacillus. Non-target substrates that included 4-methylumbelliferyl-β-d-galactopyranoside (MUGal) and l-leucine β-naphthylamide aminopeptidase (LLβ-N) were also investigated to identify nonspecific patterns of enzymatic activities in E. coli. GUD activity was found to be specific for E. coli and no further enzymatic activity was detected by other species. In addition, fluorescence assays were performed for the detection of E. coli to generate standard curves; and the sensitivity of the GUD enzymatic response was measured and repeatedly determined to be less than 10 E. coli cells in a reaction vial. The applicability of the method was tested by performing multiple fluorescence assays under pure and mixed bacterial flora in environmental samples. The results of this study showed that the fluorescence signals generated in samples using specific substrate molecules can be utilized to develop a bio-sensing platform for the detection of E. coli in drinking water. Furthermore, this system can be applied independently or in conjunction with other methods as a part of an array of biochemical assays in order to reliably detect E. coli in water.     

The responses of microbial temperature relationships to seasonal change and winter warming in a temperate grassland

Microorganisms dominate the decomposition of organic matter and their activities are strongly influenced by temperature. As the carbon (C) flux from soil to the atmosphere due to microbial activity is substantial, understanding temperature relationships of microbial processes is critical. It has been shown that microbial temperature relationships in soil correlate with the climate, and microorganisms in field experiments become more warm‐tolerant in response to chronic warming. It is also known that microbial temperature relationships reflect the seasons in aquatic ecosystems, but to date this has not been investigated in soil. Although climate change predictions suggest that temperatures will be mostly affected during winter in temperate ecosystems, no assessments exist of the responses of microbial temperature relationships to winter warming. We investigated the responses of the temperature relationships of bacterial growth, fungal growth, and respiration in a temperate grassland to seasonal change, and to 2 years’ winter warming. The warming treatments increased winter soil temperatures by 5–6°C, corresponding to 3°C warming of the mean annual temperature. Microbial temperature relationships and temperature sensitivities (Q₁₀) could be accurately established, but did not respond to winter warming or to seasonal temperature change, despite significant shifts in the microbial community structure. The lack of response to winter warming that we demonstrate, and the strong response to chronic warming treatments previously shown, together suggest that it is the peak annual soil temperature that influences the microbial temperature relationships, and that temperatures during colder seasons will have little impact. Thus, mean annual temperatures are poor predictors for microbial temperature relationships. Instead, the intensity of summer heat‐spells in temperate systems is likely to shape the microbial temperature relationships that govern the soil‐atmosphere C exchange.     

Effects of rapid temperature fluctuations prior to breeding on reproductive efficiency in replacement gilts

Rapidly cooling pigs after heat stress (HS) results in a pathophysiological condition, and because rapid temperature fluctuations may be associated with reduced reproductive success in sows, it lends itself to the hypothesis that these conditions may be linked. Objectives were to determine the effects of rapid cooling on thermal response and future reproductive success in pigs. Thirty-six replacement gilts (137.8±0.9 kg BW) were estrus synchronized and then 14.1±0.4 d after estrus confirmation, pigs were exposed to thermoneutral conditions (TN; n=12; 19.7±0.9°C) for 6 h, or HS (36.3±0.5°C) for 3 h, followed by 3 h of rapid cooling (HSRC; n=12; immediate TN exposure and water dousing) or gradual cooling (HSGC; n=12; gradual decrease to TN conditions) repeated over 2 d. Vaginal (T_V) and gastrointestinal tract temperatures (T_GI) were obtained every 15 min, and blood was collected on d 1 and d 2 during the HS and recovery periods at 180 and 60 min, respectively. Pigs were bred 8.3±0.8 d after thermal treatments over 2 d. Reproductive tracts were collected and total fetus number and viability were recorded 28.0±0.8 d after insemination. HS increased T_V and T_GI (P=0.01; 0.98 °C) in HSRC and HSGC compared to TN pigs. During recovery, T_V was reduced from 15 to 105 min (P=0.01; 0.33 °C) in HSRC compared to HSGC pigs, but no overall differences in T_GI were detected (P<0.05; 39.67 °C). Rapid cooling increased (P<0.05) TNFα compared to HSGC and TN pigs during recovery-d 1 (55.2%), HS-d 2 (35.1%), and recovery-d 2 (64.9%). Viable fetuses tended to be reduced (P=0.08; 10.5%) and moribund fetuses tended to be increased (P=0.09; 159.3%) in HSRC compared to HSGC and TN pigs. In summary, rapid cooling prior to breeding may contribute to reduced fetal viability and reproductive success in pigs.     

A method for rapid freeze fixation of plant cells

Summary We describe here an apparatus that permits rapid freeze fixation of whole cells, which are then prepared by freeze substitution and resin embedment for examination in the EM. The freezing device utilizes a rotary solenoid that rapidly plunges the specimen holder, a formvar-film-covered thin wire loop, into a well of stirred liquid propane at –180C. The rotary solenoid allows for an adjustable, repeatable immersion rate. Substitution takes place at –80 C in acetone with 2% OsO₄ and is followed by en bloc staining in either hafnium tetrachloride or uranyl acetate. We have utilized these techniques on plant cells, for which there has been relatively little published work when compared to other organisms. The results show that, with the versatile specimen holder and rapid, repeatable immersion rates, different cell types, including pollen, stamen hairs, and germinating moss spores, can be rapidly frozen with repeatable success. The improved preservation achieved with rapid freeze fixation over conventional chemical fixation reveals itself particularly in the structure of the plasmamembrane, the cytoskeleton, chromatin, and certain endomembrane systems.     

A review of bioluminescent ATP techniques in rapid microbiology

Use of firefly luciferase to assay adenosine triphosphate (ATP) extracted from microorganisms provides an easy means to enumerate microbes within minutes. The small amount of light produced is proportional to ATP and thus microbial number. The average bacterium contains around 10^?15 g ATP per cell. Present reagents permit detection of 10³ cells per tube. Luminometers currently on the market detect about 10^?12 g ATP. Proper extraction of ATP from the microbes is an essential part of any protocol, as is the removal of non-microbial ATP from, for example, somatic cells also present in samples. The technique may be applied to a wide range of samples, for example food and beverages and clinical samples such as urine. The ATP assay gives a global measure of microbial numbers, i.e. it is not species specific unless a species separation step is included in the protocol.     

Embracing a new paradigm for temperature sensitivity of soil microbes

The temperature sensitivity of soil processes is of major interest, especially in light of climate change. Originally formulated to explain the temperature dependence of chemical reactions, the Arrhenius equation, and related Q₁₀ temperature coefficient, has a long history of application to soil biological processes. However, empirical data indicate that Q₁₀ and Arrhenius model are often poor metrics of temperature sensitivity in soils. In this opinion piece, we aim to (a) review alternative approaches for characterizing temperature sensitivity, focusing on macromolecular rate theory (MMRT); (b) provide strategies and tools for implementing a new temperature sensitivity framework; (c) develop thermal adaptation hypotheses for the MMRT framework; and (d) explore new questions and opportunities stemming from this paradigm shift. Microbial ecologists should consider developing and adopting MMRT as the basis for predicting biological rates as a function of temperature. Improved understanding of temperature sensitivity in soils is particularly pertinent as microbial response to temperature has a large impact on global climate feedbacks.     

A graphical model for the evaluation of cross-transfer evidence in DNA profiles

The role of graphical models in the assessment of transfer evidence is described with particular reference to the role of cross-transfer evidence. The issues involved in the determination of factors (nodes), associations (links) and probabilities to be included are discussed. Four types of subjective probabilities are of particular interest: those for transfer, persistence and recovery; innocent acquisition; relevance; innocent presence. Examples are given to illustrate the roles of various aspects of the suspect's and victim's lifestyle and the investigation of the evidence found on the suspect and victim in assessing the probability of ultimate issue, that the suspect committed the crime.     

Development of a self-contained,indwelling vaginal temperature probe for use in cattle research

A device was developed to monitor the vaginal temperature of cattle in a research setting. This device decreases labor involved with monitoring body temperature compared with manual temperature readings, allows for continuous monitoring of vaginal temperature at 1 min intervals, and also allows for temperature measurements without the presence of a human handler or without restraint, which can agitate cattle. The device consists of a blank controlled internal drug release (CIDR) device (designed by Pfizer Animal Health as an indwelling vaginal probe) that holds an indwelling vaginal temperature probe logger. The fabrication of the vaginal probe costs approximately US $325 per unit. Similar rectal and vaginal temperature responses to lipopolysaccharide challenge were observed when vaginal and rectal temperatures were measured simultaneously in the same heifer (P>0.05). Additionally, rectal and vaginal temperatures were highly correlated (r=0.97; P<0.0001). Similar to the rectal temperature monitoring device, the vaginal device allows for the measurement of vaginal temperature without the potential biases associated with the stress response produced as a reaction to the handling by and (or) presence of humans. The vaginal temperature recording device will provide researchers with an additional inexpensive tool to study physiological responses in female cattle.     

Ultrastructure of scales in a teleost (Carassius auratus L.) after use of rapid freeze-fixation and freeze-substitution

Summary New data on the ultrastructural features of the elasmoid scales ofCarassius auratus have been obtained by use of rapid freezing with subsequent freeze-substitution in anhydrous solvents. These are compared with the results obtained using conventional aqueous fixatives.The external layer of the scales is composed of randomly oriented collagen fibres. In the first stages of mineralization, mineral deposits are located in the interfibrillary substance where dense granules appear to be active sites of mineralization. Spheritic mineralization occurs in this layer.The fibrillary plate is composed of two kinds of collagen fibres. Most of them are organized in lamellae forming the plywood-like structure. They are thicker than the so-called TC fibres, which are oriented from the basal part towards the superficial layer. These TC fibres are involved in the first stages of mineral deposition in the fibrillary plate where inotropic mineralization occurs.The mineral phase is almost always located in the interfibrillary matrix in both layers of the elasmoid scale. In this respect, teleost scales differ from those described so far in other lower vertebrates.

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Resumé Des précisions concernant les aspects ultrastructuraux des dépôts minéraux dans les écailles deCarassius auratus ont été obtenues grâce à l'utilisation de la congélation ultra-rapide suivie d'une cryosubstitution en milieu anhydre. Ces données sont comparées à celles fournies par les méthodes usuelles utilisant des fixateurs aqueux.La couche externe des écailles comprend des fibres collagènes disposées sans ordre apparent. Les dépôts minéraux se produisent surtout dans la substance interfibrillaire où des granules denses semblent représenter des sites actifs au cours de la minéralisation apparentée au type sphéritique.La plaque basale comporte deux catégories de fibres collagènes. Les unes, les plus nombreuses, de plus fort diamètre, sont organisées en lamelles formant une structure en contre-plaqué; les autres appelées fibres TC, orientées de la base de l'écaille vers la zone superficielle, jouent un rôle important dans les premières phases de la minéralisation de type inotropique dans cette partie de l'écaille.Dans les deux couches de l'écaille, la phase minérale est surtout trouvée dans la substance interfibrillaire. De ce fait, les écailles élasmoides des Téleostéens peuvent être distinguées des autres écailles dermiques connues de Vertébrés inférieurs.