The effects of temperature on enzyme structure and function have long been of interest to comparative physiologists and biochemists, and the findings of the past ten years have shown convincingly that temperature stresses on enzymes, and the adaptive responses of enzymes to compensate for these stresses, have played an important role in biological evolution. Many aspects of enzymatic adaptation to temperature have been treated thoroughly in recent monographs (3) and reviews (48, 56, 104), and these sources provide extensive bibliographies of the hundreds of papers dealing with temperature-enzyme interactions. This review attempts to com­ plement existing reviews and to provide an overview of the important structure­ function interrelationships that characterize enzymatic adaptation to temperature. This review also attempts to show how the effects of temperature on enzyme struc­ ture and function may be instrumental in establishing the thermal optima and tolerance limits of metabolic function and, thereby, of the organism itself. Hope­ fully, this discussion will help to provide a bridge between the interesting new discoveries of enzyme chemists and interests of ecologists, systematists, and zoo­ geographers. Attention is first directed toward the sources of thermal stress on enzyme systems; this analysis reveals that most aspects of enzyme structure and function are highly sensitive to temperature variation, whether this variation occurs rapidly or over long evolutionary time. Next the so-called "goals" of temperature adaptation are qut­ lined, namely the set of properties that must be conserved in all organisms, under all thermal regimes. The molecular mechanisms instrumental in effecting these critical conservative adaptations are then discussed. Several distinct classes of mech-

Temperature Adaptation of Enzymes: Biological Optimization Through Structure-Function Compromises

Compared to their vertebrate counterparts in traditional husbandry, insects are extremely efficient at converting organic matter into animal protein and dietary energy. For this reason, insects for food and feed show great potential as an environmentally friendly choice in future food systems. However, to obtain a true assessment of this, more information is needed about the production systems. Currently, only six studies applying the life cycle assessment (LCA) method to insect production systems have been published. The studies are heterogenous and thus difficult to compare. The aim of this paper was to establish a versatile reference framework that would allow for the selection of standardized settings for LCA applications in insect production systems, taking both the peculiarity of each system and the latest developments in food LCA into account. It is recommended that future LCAs of insect production systems take the following into account: (1) clear definition of the insect species and life stages included in the LCA, (2) use of at least two of the following types of functional units: nutritional, mass, or economic-based, (3) collection of empirical data in situ (e.g., on farms/production sites), (4) comparative analysis where production systems produce products that are realistic alternatives to the insect species under investigation, (5) inclusion of additional or previously unconsidered unit processes, such as processing and storage and waste management, and (6) use of a wide range of impact categories, especially climate change, resource consumption, nutrient enrichment potential, acidification potential, and impacts on land and water consumption in order to allow for comparison between studies.

/pdf/life-cycle-assessment-of-edible-insects-for-food-protein-a-zwb1ra6k64.pdf

Life cycle assessment of edible insects for food protein: a review

In many parts of the world, climate change is increasing the frequency and severity of heat waves. How do heat waves impact short-lived poikilotherms such as insects? In the cricket, Gryllus texensis, 6 days of elevated temperatures (i.e. 7°C above the average field temperature and 5°C above their preferred temperature) resulted in increased egg laying, faster egg development and greater mass gain. The increased temperature also increased activity of phenoloxidase and lysozyme-like enzymes, two immune-related enzymes, and enhanced resistance to the Gram-negative bacterium Serratia marcescens. When given a sublethal S. marcescens infection, G. texensis maintained increased reproductive output at the elevated temperature (33°C). These data suggest that heat waves could result in more numerous, disease resistant, crickets. However, resistance to the Gram-positive bacterium, Bacillus cereus was lower at temperatures above or below the average field temperature (26°C). A sublethal infection with B. cereus reduced egg laying at all temperatures and suppressed the increase in egg laying induced by higher temperatures. These results suggest that for some species-pathogen interactions, increased temperatures can induce trade-offs between reproduction and disease resistance. This result may partly explain why G. texensis prefers temperatures lower than those that produce maximal reproductive output and enhanced immune function.

/pdf/some-like-it-hot-the-effects-of-climate-change-on-3y1dsmv0nr.pdf

Some like it hot: the effects of climate change on reproduction, immune function and disease resistance in the cricket Gryllus texensis

The temperature-size rule (TSR), which states that body size increases at lower developmental temperatures, appears to be a near-universal law for ectotherms. Although recent studies seem to suggest that the TSR might be adaptive, the underlying developmental mechanisms are thus far largely unknown. Here, we investigate temperature effects on life-history traits, behaviour and physiology in the copper butterfly Lycaena tityrus in order to disentangle the mechanistic basis for the above rule. In L. tityrus the larger body size produced at a lower temperature was proximately due to a greater increase in mass, which was caused by both behavioural and physiological mechanisms: a much-increased food intake and a higher efficiency in converting ingested food into body matter. These mechanisms, combined with temperature-induced changes at the cellular level, may provide general explanations for the TSR. Body fat and protein content increased in butterflies reared at the higher temperature, indicating favourable growth conditions. As predicted from protandry theory, males showed reduced development times, caused by higher growth rates compared to females. The latter was itself related to a higher daily food consumption, while the total food consumption (due to the females' longer developmental period) and assimilation was higher in females and may underly the sexual body size dimorphism.

Why get big in the cold? Towards a solution to a life-history puzzle.

Publisher Summary
This chapter discusses the carbohydrate metabolism of gastropods. D-glucose is the most common monosaccharide and has been detected in the blood and tissues of many gastropods. Other sugars also occur, in particular D-galactose, that are either stereoisomers or derivatives of monosaccharides. Glycogen and galactogen are the main storage polysaccharides. Whereas glycogen occurs in most gastropod tissues and serves as a general energy source, galactogen is generally confined to the albumen gland and eggs of adult pulmonate snails and the albumen gland region of the palliai oviduct of some prosobranchs, and it serves as a specialized energy source in reproduction. Glycogen is a branched-chain homopolysaccharide of D-glucose in α-1,4 linkage with branches joined through α-1,6 linkages. The degree of branching and the length of the outer branches of the glycogen from the snail Biomphalaria glabrata are similar to those of glycogens from other animal sources.

Carbohydrate metabolism of gastropods

1.

Adulte Mittelmeerfeldgrillen wurden vom Zeitpunkt der Imaginalhautung an bei 8 konstanten und 8 tagesperiodisch alternierenden Temperaturen gehalten, die den gesamten Lebensbereich von Gryllus bimaculatus erfassen. Bestimmt wurden die mittlere Lebenserwartung, Nahrungsverbrauch und Kotproduktion, Dauer der Nahrungspassage durch den Darm und Restnahrstoffe in den Exkrementen, Eiablage, Entwicklungszeit und die Entwicklungsrate der Eier.




2.

Gryllus bimaculatus zeigt fur die untersuchten physiologischen Leistungen unter konstanten Temperaturbedingungen unterschiedliche Temperaturanspruche und Optimalbereiche. Adulte Tiere weisen die langste Lebensdauer bei 20°C auf und nehmen erst bei Temperaturen uber 10°C Nahrung zu sich. Die gunstigste Futterverwertung erfolgt zwischen 27° und 34°C. Hautungen zu Imagines konnten erst ab 20°C beobachtet werden. Das Temperaturpraferendum von 34±2°C liegt in einem Bereich mit zunehmender Mortalitatsrate. Bei Temperaturen unter 20°C legen die Weibchen keine Eier ab, bei 34°C erreicht die Eiproduktion ein Maximum von 1000 Stuck pro Tier mit einer Ausschlupfrate von 53%. Die Embryonalentwicklung beginnt im Ei bei 16,6°C, ihre kurzeste Entwicklungsdauer erreichen die Larven bei 34°C.




3.

Mit Ausnahme von Lebensdauer und Eiproduktion fordern alternierende Tagestemperaturen die physiologischen Leistungen adulter Gryllus bimaculatus nicht. Die Zahl der abgelegten Eier liegt bei Wechseltemperaturen um 20° und 27°C 1,4–3mal so hoch wie bei den mittleren konstanten Temperaturwerten. Mit konstanten 34°C vergleichbare Ergebnisse werden fur alle gemessenen Parameter nur bei Wechseltemperaturen um 27°C annahernd erreicht.




4.

Die Produktion organischer Substanz (Gewichtsveranderungen und Eiproduktion) und die Embryonalentwicklungszeit folgen annahernd den von Kaufmann (1932) aufgestellten Temperatursummenregeln.




5.

Bei konstanten Haltungstemperaturen von 13° und 10°C nehmen die Tiere noch relativ viel Futter auf, produzieren aber kaum mehr Kot. Eine Erhohung des Quotienten aus Futterverbrauch zu Kotproduktion von Q=4–6 bei 20°–38°C auf Q=7–39 bei 10° und 13°C bedeutet in diesem Temperaturbereich eine Speicherung von Nahrstoffen im Korper, wie sie schon bei biochemischen Ganztieranalysen gefunden wurde (Hoffmann, 1973).




6.

Tagesperiodisch alternierende Temperaturen sind durch die Amplitude, Aufheiz- und Abkuhlgeschwindigkeit, obere und untere Grenztemperaturwerte, die zeitliche Lage und das Verhaltnis von Warme- zu Kalteperiode zu charakterisieren. Daruberhinaus werden physiologische Leistungsanpassungen durch den 24-stundigen Licht-Dunkel-Zyklus, Beziehungen des Temperaturwechsels zum Licht-Dunkel-Wechsel und durch endogene Rhythmen mitbestimmt.

Wirkung von konstanten und tagesperiodisch alternierenden Temperaturen auf Lebensdauer, Nahrungsverwertung und Fertilität adulter Gryllus bimaculatus

1.

Structural, kinetic and thermodynamic activation properties of muscle pyruvate kinases from invertebrate species adapted to different thermal environments were examined.




2.

Structural rigidity, as estimated by ammonium sulfate precipitation and heat inactivation temperature, is positively correlated with acclimatization temperature of the organism (Fig. 1).




3.

Km-values for PEP are hardly influenced by experimental temperatures within the normal temperature range of the species (Fig. 2). A good correlation, however, exists betweenKm-values and the capacity of tissues for aerobic glycolysis (Fig. 3).




4.

All pyruvate kinases can exist in two (or more) temperature-dependent conformational states. Sizes of ΔH≠-values are correlated with the species' acclimatization temperature (Fig. 6) but not with the temperature variability in the cells (Fig. 7).




5.

A correlation exists between the free energy of activation ΔG≠, body temperatures and the capacity of muscles for aerobic glycolysis (Table 2).

Catalytic efficiency and structural properties of invertebrate muscle pyruvate kinases: Correlation with body temperature and oxygen consumption rates

1.

Adulte Gryllus campestris und Gryllus bimaculatus wurden bei drei bzw. funf verschiedenen konstanten und einer tagesperiodisch wechselnden Versuchstemperatur 3–4 Wochen lang gehalten und die Ganztiere bzw. ihre Hamolymphe auf Gesamtwassergehalt, osmotischen Druck, Gehalt an Na, K, Ca, Cl, Protein, NPS, Gesamtlipide, Gesamtkohlenhydrate, niedermolekulare Zucker, Polysaccharide, organische Sauren, Nucleinsauren, Chitin und Aschegehalt untersucht. Die Hamolymphe wurde auf Polyacrylamid elektrophoretisch getrennt (Abb. 5).




2.

Die Hamolymphe von Gryllus campestris weist bei der Gefrierpunktserniedrigung und allen anorganischen Kationen ein Maximum bei 10°C auf. Osmotischer Durck, Gesamtlipide und NPS der Hamolymphe von Gryllus bimaculatus haben bei 5°C ein Maximum, Gesamtprotein, Aldosen und Gesamtkohlenhydrate bei 13°C (Abb. 1-4).




3.

Die Ganztieranalyse von Gryllus bimaculatus ergibt ein Maximum fur Gesamtlipide, Gesamtpolysaccharide und NPS bei 5°C, fur niedermolekulare Kohlenhydrate und Glykogen bei 10°C. Der Lactat/Pyruvat-Quotient nimmt mit fallender Temperatur zu, der Wassergehalt der Tiere dagegen ab. Die Nucleinsauren unterscheiden sich bei den verschiedenen Haltungstemperaturen nur sehr wenig, Chitin zeigt keine Veranderungen. Die grosten Variationen in Abhagigkeit von der Haltungstemperature findet man bei den Lipiden und den Polysacchariden. Die Summe aus den Trockengewichten von Proteinen und Lipiden ist bei allen Haltungstemperaturen annahernd gleich, einer Zunahme an Lipiden bei tiefen Temperaturen stehen gleich grose Abnahmen an Proteinen gegenuber (Abb. 6-13).




4.

Die Wechselteperatur wirkt bei den verschiedenen untersuchten Parametern unterschiedlich (Tabelle 3).




5.

Bei fast allen Stoffklassen ist ein ausgepragter Sexualdimorphismus vornanden.




6.

Der Sauerstoffverbrauch ist temperaturabhangig mit einem Q10-Wert von etwa 2,5.

Der Einfluß der Temperatur auf die chemische Zusammensetzung von Grillen (Gryllus, Orthopt.).

Main storage substances in blowflies from Spitsbergen are protein (313.9 mg/g d.w.) and lipids (365.1 mg/g). Laboratory stock individuals (30° C) on the contrary, do not accumulate such quantities of lipids but have low-molecular carbohydrates for their main organic constituent. Mean caloric values range from 5.41 to 5.73 kcal/g dry weight in Spitsbergen species, but reach only 4.52 kcal/g in laboratory cultured Protophormia. Results are discussed in relation to the effect of biotop conditions on the calorific value of flies and their importance as food quality.

Klaus-Hubert Hoffmann

Papers

Wirkung von konstanten und tagesperiodisch alternierenden Temperaturen auf Lebensdauer, Nahrungsverwertung und Fertilität adulter Gryllus bimaculatus

Catalytic efficiency and structural properties of invertebrate muscle pyruvate kinases: Correlation with body temperature and oxygen consumption rates

Der Einfluß der Temperatur auf die chemische Zusammensetzung von Grillen (Gryllus, Orthopt.).

Organic body constituents of Protophormia terrae-novae (Dipt.) from Spitsbergen compared with flies from a laboratory stock.