The Nature of Biological Systems as Revealed by Thermal Methods

University of Pecs, Biophysical Department, Faculty of Medicine, Hungary NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW eBook ISBN 1-4020-2219-0 Print ISBN 1-4020-2218-2 2005 Springer Science + Business Media, Inc. Print 2004 Kluwer Academic Publishers Dordrecht No part of this eBook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Springer's...

Scanning microcalorimetry studies of helix coil transition of polysaccharides

Microbial polysaccharides are biotechnologically produced and have a paramount relevance in industrial food and non-food applications (Sutheriand 1998). Their 'quality' resides in their reproducible chemical structore (conirary to many plant gums) and their ecological properties (contrary to many synthetic polymers). In addition to the valuable physical properties (they act as emulsion stabilisers, gelling agents, inhibitors of crystal formation, viscosity controllers), many of them exhibit...

Reactions and interactions between food constituents

In addition to thermal phenomena of isolated constituents, reactions and interactions between food constituents can also be evidenced by calorimetric techniques. The browning reactions between proteins and reducing sugars, part of the Maillard reaction, are exothermic reactions that can be followed by DSC. They are associated with relatively small enthalpies (less than 100 J g) and take place at temperatures above the Tg of the involved ingredients. Investigations of the Maillard reaction by...

Methods

In this study, the heat capacity function of the thermal transition of protein was simulated using the experimental values of thermal transition of lysozyme 4,5 . where the parameters for the two thermodynamic states, native (N) and denatured (D), aN, bN, aD, bD were assumed as 45 J K-2mol-1, 22 kJ K-1mol-1, 19 J K-2mol-1 and 29 kJ K-1mol-1, respectively. T0 was 320 K and the midpoint temperature of the transition was assumed to be equal to this temperature. Using the thermodynamic Eqs (4) and...

References

Ackermann, T. (1969) Physical States of Biomolecules Calorimetric Study of Helix-Random Coil Transitions in solution in H. D. Brown (ed), Biochemical Calorimetry, Academic Press, New York, 121-148. Anderson, C. F. and Record, M. T. (1990) Ion Distributions around DNA and Other Cylindrical Polyions - Theoretical Descriptions and Physical Implications Annu. Rev. Biophys. Biophys. Chem, 19, 423-465. Anderson, C. F. and Record, M. T. (1995) Salt Nucleic-acid Interactions Annu. Rev. Phys. Chem., 46,...

Myosin

Myosin is a representative of extensively studied last years 'molecular motors', i.e. the proteins which realize in living cells the transduction of chemical energy of ATP hydrolysis into mechanical work. Different myosins are very diverse D. Lorinczy (ed.), The Nature of Biological Systems as Revealed by Thermal Methods, 127-158. 2004 Kluwer Academic Publishers. Printed in the Netherlands. both in their structure and in the functions in the cell. On the basis of phylogen-etic analysis all...

Thermogravimetry of food samples

Thermo-gravimetric analysis (TG) is the thermal analysis related to the mass loss during a temperature scan at a given heating rate. It therefore reveals the vaporization of volatiles that can be either original components of the food examined, or the products of the thermal decomposition of some of them. The released compounds stripped toward the exterior by a gentle nitrogen stream can be identified by conveying the out-flow into a gas chromatographer or an IR or Fig. 9 Isothermal 'cooking'...

Introduction

Today's Thermal Analyses (TA) represent a very wide panoply of methods that allow accurate monitoring of several physical and chemical properties of a given system, which are directly affected by temperature changes. Some of these methods have been adapted to isothermal investigations and therefore are employed to check changes that take place in a given lapse of time. The physical principles underlying thermal analyses apply to every physical state, namely gaseous, liquid and solid, provided...

Theory

Many biopolymers undergo conformational transitions as a function of composition and or temperature. Conformational transitions are 'in themselves' conceptually analysed as phase transitions, since the polymer state is characterised by a difference in the structural and thermodynamic properties. We shall briefly summarise the experimental results which can be obtained by differential scanning calorimetry on the helix coil (in some cases including gel sol) conformational transition in linear...

Calculations of the heat capacity in the liquid state of dry carbohydrates

Generally, the heat capacity of dry biopolymers such as carbohydrates in the liquid or rubbery states is calculated from the standard thermodynamic relationship 26, 27 C p C v + TV a2 p C vib (biopoly) + C c0nf (biopoly) + C e rt (biopoly) (15) All quantities must be known as a function of temperature over the full range of calculation. The experimental heat capacity is, thus, separated into a vibrational heat capacity Cvb(biopoly), the conformational heat capacity Cconf(biopoly), and the...

Sleep and hibernation

Most social insects are diurnal foragers. When they stay inside their nests at night, they perform nest duties like cleaning cells, care for the young or thermoregulation. Nevertheless, in honeybees the most active foragers pause in a state which closely resembles sleep. The phenomenon of sleep is not restricted to mammals, but can also be found in other vertebrates like birds or turtles and even in invertebrates 36, 37 . It may therefore not be too surprising to find sleep-like behaviour in...

Instrumentation

Oxygen Production From Corn

It is advantageous to perform simultaneous determinations of the rates of heat and CO2 production and oxygen consumption in order to get a more complex picture of the underlying plant metabolism. But there are limitations for the application of the corresponding electrodes when the vessels are small, the electrodes not submerged in the solution, the solutions not stirred, or the samples solid. To overcome such problems Criddle et al. 25 made threefold experiments a first run with only the...

Thermal behaviour of raw and reconstituted foods

Most of the physico-chemical effects observed with food constitu ents are also found in the calorimetric curves of raw and reconstituted foods examples are coffee beans, chicory roots, cereals or milk powders and infant formulas (Raemy, 1981 Raemy and Lambelet, 1982 Raemy and Loliger, 1982 Raemy et al., 1983). The thermal phenomena observed with pure minor constituents will, however, not be observed once these constituents are dispersed in a food matrix. Many raw and reconstituted foods contain...

DSC examination of the lumbar intervertebral disc

Low back pain is one of the most common health problems affecting western society. At some point during their lifetime, 80 of the population will experience these symptoms, and as many as 60 may have suffered from it in the past year 19 . Beside the inconveniences, the cost of low back pain to the society is also estimated extremly high 20, 21 . Low back pain is most frequently due to the degeneration of the intervertebral discs 22, 23 . The degenerative processes begin early in adulthood and...

The Calorimetricrespirometric CR ratio

For measurements by direct and indirect calorimetry, the theoretical oxycaloric equivalent is the same as the expected ratio of the calorimetric heat flux and the respirometric oxygen flux, the CR ratio, For whole animals in normoxic conditions, their homeostatic mechanisms ensure that the CR ratio is the same as the above generalised oxycaloric equivalent 81 with the Cori cycle in the liver converting to glucose any lactate in the circulating blood after much of it has been oxidised in the...

The bioreactor as a calorimeter

One of the problems in the design of industrial bioreactors and fermenters is to dissipate the heat produced by the cells. If, instead of simply removing utilising it after an exergy analysis, the rate of heat flow were to be measured, then the rate of metabolism would be assessed continuously on-line. To this end, some years ago von Stockar's group 27 adapted a 2-L Mettler RC-1 heat accumulation calorimeter (see 21 for the classification of calorimeter types) originally designed for the safety...

Conclusion Of The Topic Heat Production

Social insects have been investigated in many aspects. Evolutionary biologists are fascinated by their altruism, and the genetical basis for this is still under investigation. Ecologists have to deal with insect societies as they are key species in most ecosystems. Behavioural biologists investigate their means of communication and selforganized decision-making. For a physiologist dealing with animal energetics, social insects are particularly interesting as they can be viewed from two...

DSC examination of the hyaline cartilage

Hyaline Cartilage Mandibular Condyle

Characteristic features of the normal hyaline cartilage Connective and supportive tissues of the human body are characterized by the large amount of basic substances filling the gap between cells and significantly influencing the mechanical properties of the tissue. In opposite to the connective tissues - where the ground substance is mainly formed by fibers - in case of supportive tissues, like for example cartilage, other organic and inorganic materials are typical for the basic substance....

Actin

Reversible Therma Denaturation

Actin is found in virtually every eukariotic cell. Actin filaments have a crucial role in biological motility as the main partners of the myosin-based 'motor' systems and as the major constituent of the cytoskeleton. Filamentous actin (F-actin) is a double-stranded spiral polymer of actin monomers. Monomeric actin (G-actin) is a globular protein with molecular mass of 42 kDa. It consists of a single polypeptide chain with a bound ATP and a divalent cation. An important feature of actin is its...

Colony defense

As we have seen in the previous section, social insect colonies contain large amounts of energy, either as brood or as stock (honey, pollen). The energy resources stored in a nest are alluring to predators and parasites which leads to a strong selection to evolve means of colony defence. The most annoying aspect of social insect life to humans is that the vast maj ority of all species have evolved poisonous stings. Even without stingers, which have been lost in many ants and some bees, the...

Thermal behaviour of major food constituents

In food many physicochemical effects can be observed in the temperature range between -50 C and 300 C. These thermal phenomena may be either endother-mic, such as melting, gelatinisation, denaturation, evaporation, or exothermic such as crystallization, oxidation, fermentation. Glass transitions are observed as a shift in the baseline this information is associated with water content and water activity determinations. Specific heats (cp) of foods can be calculated (Gekas, 1992) on the basis of...

Experimental heat capacity

Experimental data heat capacity should be the starting point to quantitative thermal analysis. Figure 1 shows the experimental heat capacity of a-D-glucose by adiabatic calorimetry and standard differential scanning calorimetry (DSC). The low-temperature experimental Cp of solid a-D-glucose, as collected from paper 38 , was used to calculate the contribution of the group vibrations and the ATHAS Scheme allowed measurement of the contributions from the skeletal vibrations, as described below and...

Colonies of social insects

Social insect colonies were since long particularly fascinating for biologists because of the ability to maintain social homeostasis. Honeybees are able to regulate winter cluster or brood comb temperature precisely, ants control humidity in their nest hills, and even at cold days the temperature in most insect colonies is above the ambient. As early as 1837, Newport measured the temperature inside bumblebee nest with mercury thermometers 55 . But as we will see, the ability for maintenance of...

Using DSC for monitoring rise of fat crystals in complex emulsified systems

In complex emulsions used for preparation of milk-whipped creams or ice creams, lipid ingredient comes mostly from milk fat (in United States) or vegetable fats (palm oil or palm kernel oil) in other countries. These lipids are constituted by a wide diversity of fatty acids and triacylglycerols (TG), each characterized by its own melting temperature 23, 38 . Their chemical and physical properties may be modified by hydrogenation or fractionation, with characteristic melting profiles and...

DSC and isothermal calorimetry

Amylose Lipid Complex

It is well known that the interpretation of any DSC trace requires a preliminary assessment of the base line. The base line of the DSC trace of many food samples can be rather 'irregular', when compared to that underlying the DSC peak of the fusion of Indium (the usual standard compound). This simply means that food samples undergo changes of the heat capacity with no parallel changes of enthalpy. This kind of processes can take place several times in the course of the temperature scan, since...

Energy consumption for development

Principally two different modes of development can be found in insects an incomplete (hemimetabolous) and complete (holometabolous) development. Hemimetabolic insects do not have larvae, which are defined as juveniles possessing at least one trait which can not be found in adults. Juveniles with hemi-metabolic development resemble their parents, except that they have no wings. A life cycle with two distinct morphs, the larva and the adult (sometimes denoted as 'imago'), is characteristic for...

Combination of a bioreactor with a flow microcalorimeter

By 1997, Kemp et al 19 had developed a solution for measuring the heat flow rate of animal cells growing under the controlled conditions of the bioreactor that is independent of the size of the culture vessel. It allows the measurement of the heat produced in industrial-scale plant by circulating the cell suspension from the bioreactor to the flow calorimeter and then returning it. As a model for a large-scale facility, a 3-L Applikon bioreactor containing a stirred suspension of Chinese...

Heat capacity of the solid state

What Vibrational Heat Capacity

The heat capactty of the solid biomaterials such as glucose, dry starch and starch-glassy water is to be computed from approximate vibrational spectra, as summarized earlier based on the experimental low-temperature heat capacity. This analysis represents the well-established ATHAS scheme 9, 43, 44 for synihetic polymers. There are 3N vibrational degrees of freedom in the solid state with N representing the total numbers of atoms in small biomolecules, or in the constitutional repeating unit of...

Energetics of social insect parasites

Another type of enemies of social insects are parasites. As honeybees are economically and ecologically important due to their honey production and pollination activities, research on bee parasites focuses on the treatment of these bee pests. From an energetical point of view, only two bee parasites have been investigated in some detail, the bee mite Varroa destructor, which is a recently in troduced brood parasite of great economical importance, and the wax moth Galleria mellonella. Varroa...

Locomotor activities

Flying insects exhibit the highest specific heat production rates known in the animal kingdom 23 . Nearly all heat during flight is produced by the thoracal muscles, which have an extraordinary power output. The reason for this lies in the relatively small body mass of insects. In this case inertia plays nearly no role during locomotion. Gliding flight is thus known only for a few species (some butter- and dragonflies) and most flying insects have to continuously beat their wings with high...

Heat production in plant tissue

Investigating plant tissues and seeds in a calorimeter, a caveat is necessary except for tissue cultures, samples are not sterile and microbial growth may strongly interfere in the obtained heat dissipation. An exponentially growing heat output during experiments with plant tissues is a clear sign of microbial contamination. The danger can be minimized by surface sterilization with diluted hypochlorite, addition of microbial inhibitors and use of solutions that do not support bacterial growth...