The physiologist Johann Autenrieth (1772–1835) at Tübingen University: early reports on biological rhythms and their use for medical lectures

Johann, Heinrich, Ferdinand von Autenrieth [1772–1835], was a teacher of anatomy, physiology and pharmacology at the University of Tübingen, Germany. He was the author of a famous textbook on Physiology and one of the earliest pharmacologists [Öffentlicher Lehrer der Arzneykunst]. In his textbooks, he presented a lot of information that and how biological rhythms influenced physiological functions in the human body, the book was used for his medical lectures for students. He can be regarded as on of the earliest chronophysiologists. Most important, he assumed a chemical stimulation responsible for generating the periodicities in the human body.     

Detecting Change in Biological Rhythms: A Multivariate Permutation Test Approach to Fourier‐Transformed Data

Treatment‐related changes in neurobiological rhythms are of increasing interest to psychologists, psychiatrists, and biological rhythms researchers. New methods for analyzing change in rhythms are needed, as most common methods disregard the rich complexity of biological processes. Large time series data sets reflect the intricacies of underlying neurobiological processes, but can be difficult to analyze. We propose the use of Fourier methods with multivariate permutation test (MPT) methods for analyzing change in rhythms from time series data. To validate the use of MPT for Fourier‐transformed data, we performed Monte Carlo simulations and compared statistical power and family‐wise error for MPT to Bonferroni‐corrected and uncorrected methods. Results show that MPT provides greater statistical power than Bonferroni‐corrected tests, while appropriately controlling family‐wise error. We applied this method to human, pre‐ and post‐treatment, serially‐sampled neurotransmitter data to confirm the utility of this method using real data. Together, Fourier with MPT methods provides a statistically powerful approach for detecting change in biological rhythms from time series data.     

Disrupted seasonal biology impacts health,food security and ecosystems

The rhythm of life on earth is shaped by seasonal changes in the environment. Plants and animals show profound annual cycles in physiology, health, morphology, behaviour and demography in response to environmental cues. Seasonal biology impacts ecosystems and agriculture, with consequences for humans and biodiversity. Human populations show robust annual rhythms in health and well-being, and the birth month can have lasting effects that persist throughout life. This review emphasizes the need for a better understanding of seasonal biology against the backdrop of its rapidly progressing disruption through climate change, human lifestyles and other anthropogenic impact. Climate change is modifying annual rhythms to which numerous organisms have adapted, with potential consequences for industries relating to health, ecosystems and food security. Disconcertingly, human lifestyles under artificial conditions of eternal summer provide the most extreme example for disconnect from natural seasons, making humans vulnerable to increased morbidity and mortality. In this review, we introduce scenarios of seasonal disruption, highlight key aspects of seasonal biology and summarize from biomedical, anthropological, veterinary, agricultural and environmental perspectives the recent evidence for seasonal desynchronization between environmental factors and internal rhythms. Because annual rhythms are pervasive across biological systems, they provide a common framework for trans-disciplinary research.     

Melatonin administration to blind people: phase advances and entrainment.

The purpose of this study was to test the phase-shifting and entraining effects of melatonin in human subjects. Five totally blind men were found in a previous study to have free-running endogenous melatonin rhythms. Their rhythms were remarkably stable, so that any deviation from the predicted phase was readily detectable. After determination of their free-running period and phase, they were given exogenous melatonin (5 mg) at bedtime (2200 hr) for 3 weeks, in a double-blind, placebo-controlled trial. The effects on the endogenous melatonin rhythm were assessed at intervals ranging from several days to 2 weeks. Exogenous administration of melatonin phase-advanced their endogenous melatonin rhythms. In three of the subjects, cortisol was shown to be phase-shifted in tandem with the melatonin rhythm. A sixth subject [one of the coauthors (JS)] was previously found to have free-running cortisol and temperature rhythms and was plagued by recurrent insomnia and daytime sleepiness. He had tried unsuccessfully to entrain his rhythms for over 10 years. After he took melatonin (7 mg at 2100 hr), his insomnia and sleepiness resolved. Determination of his endogenous melatonin rhythm after about a year of treatment demonstrated endogenous rhythms that appeared normally entrained. The treatment of blind people with free-running rhythms has many advantages for demonstrating chronobiological effects of hormones or drugs.     

Seven-day human biological rhythms: An expedition in search of their origin,synchronization, functional advantage,adaptive value and clinical relevance

This fact-finding expedition explores the perspectives and knowledge of the origin and functional relevance of the 7 d domain of the biological time structure, with special reference to human beings. These biological rhythms are displayed at various levels of organization in diverse species – from the unicellular sea algae of Acetabularia and Goniaulax to plants, insects, fish, birds and mammals, including man – under natural as well as artificial, i.e. constant, environmental conditions. Nonetheless, very little is known about their derivation, functional advantage, adaptive value, synchronization and potential clinical relevance. About 7 d cosmic cycles are seemingly too weak, and the 6 d work/1 d rest week commanded from G-d through the Laws of Mosses to the Hebrews is too recent an event to be the origin in humans. Moreover, human and insect studies conducted under controlled constant conditions devoid of environmental, social and other time cues report the persistence of 7 d rhythms, but with a slightly different (free-running) period (τ), indicating their source is endogenous. Yet, a series of human and laboratory rodent studies reveal certain mainly non-cyclic exogenous events can trigger 7 d rhythm-like phenomena. However, it is unknown whether such triggers unmask, amplify and/or synchronize previous non-overtly expressed oscillations. Circadian (~24 h), circa-monthly (~30 d) and circannual (~1 y) rhythms are viewed as genetically based features of life forms that during evolution conferred significant functional advantage to individual organisms and survival value to species. No such advantages are apparent for endogenous 7 d rhythms, raising several questions: What is the significance of the 7 d activity/rest cycle, i.e. week, storied in the Book of Genesis and adopted by the Hebrews and thereafter the residents of nearby Mediterranean countries and ultimately the world? Why do humans require 1 d off per 7 d span? Do 7 d rhythms bestow functional advantage to organisms? Is the magic ascribed to the number 7 of relevance? We hypothesize the 7 d time structure of human beings is endogenous in origin – a hypothesis that is affirmed by a wide array of evidence – and synchronized by sociocultural factors linked to the Saturday (Hebrews) or Sunday (Christian) holy day of rest. We also hypothesize they are representative, at least in part, of the biological requirement for rest and repair 1 d each 7 d, just as the circadian time structure is representative, in part, of the biological need for rest and repair each 24 h.     

Sinai Tschulok (1875–1945)—a pioneer of Cladistics

Sinai Tschulok emigrated from the Ukraine to Switzerland, where he studied natural sciences, in particular biology. He founded and managed his own high school, which prepared students for entry to university-level education. This left him little time for research, which may explain why his work largely fell into oblivion. He did publish two influential books, however (Tschulok, S., 1910, Das System der Biologie in Forschung und Lehre, Gustav Fischer, Jena and Tschulok, S., 1922, Deszendenzlehre, Gustav Fischer, Jena), which were cited and commented upon favourably by both Walter Zimmermann and Willi Hennig. The most important point, in their opinion, was how Tschulok's explication of biological systematics had turned the "natural system" into a proof for the "Theory of Descent". The influence of Walter Zimmermann on Willi Hennig and the development of phylogenetic systematics is well known. Here some parts of Tschulok's writings are discussed that render him a pioneer in Cladistics.
© The Willi Hennig Society 2009.     

Perspectives in chronobiology of air pollution

In a series of experiments, male and female Sprague Dawley rats, kept in light (L) from 06(00) to 18(00) alternating with darkness (LD 12:12) inhaled different concentrations of carbon monoxide (50-1,700 ppm) at each of two test times, 12 h apart. A decrease in flow of CO2 (VCO2) resulting from CO inhalation was greater in the active dark (D) than resting light (L) span. Experimental hypoxic mortality of male and female mice also shows circadian variations, being greater in the D than in the L span. Moreover, a difference of mortality was observed betwen hypoxic exposures performed at 12(00) (in LD or DL) and hypoxic exposures performed at 00(00) (in LD or DL). Such results await tests of any extent to which they model responses of human beings to air pollution. In human beings any external environmental circadian, circaseptan and circannual variations in air pollution as such may serve to variable extent as socioeconomic synchronizers of innate rhythms with a corresponding frequency, rather than as solely generators of time patterns in any physiopathologic response to air pollution.     

Some Tools to Analyze Changes of Rhythms in Biological Time Series

The moving window principle applied to the khi-square periodogram allows, through local successive examinations, a comprehensive study of the biological time series. This method puts forward several cases of transition linked to environmental or physiological changes. Furthermore, we applied the Grassberger and Procaccia method (1983) for the analysis of more complex transition problems. The method helps to detect chaotic properties in behavioral activity rhythms.     

Some Tools to Analyze Changes of Rhythms in Biological Time Series

The moving window principle applied to the khi-square periodogram allows, through local successive examinations, a comprehensive study of the biological time series. This method puts forward several cases of transition linked to environmental or physiological changes. Furthermore, we applied the Grassberger and Procaccia method (1983) for the analysis of more complex transition problems. The method helps to detect chaotic properties in behavioral activity rhythms.     

Humboldt,Darwin, and population

Conclusions I have attempted to clarify some of the pathways in the development of Darwin's thinking. The foregoing examples of influence by no means include all that can be found by comparing Darwin's writings with Humboldt's. However, the above examples seem adequate to show the nature and extent of this influence. It now seems clear that Humboldt not only, as had been previously known, inspired Darwin to make a voyage of exploration, but also provided him with his basic orientation concerning how and what to observe and how to write about it. An important part of what Darwin assimilated from Humboldt was an appreciation of population analysis as a tool for assessing the state of societies and of the benefits and hardships which these societies can expect to receive from the living world around them.Darwin exhibited in his Journal of Researches a casual interest in the economic and political conditions of the countries he visited, but these considerations were much less important to him than to Humboldt. Instead, Darwin, with the assistance of Lyell's Principles of Geology, shifted from Humboldt's largely economic framework to a biological one built around the species question. This shift led Darwin away from a consideration of how the population biology of animals was related to man's economy to focus instead upon how population biology fitted into the economy of nature.Humboldt's Personal Narrative served very well as a model for Darwin's Journal of Researches, thereby helping Darwin gain scientific eminence. The Journal of Researches, like virtually all of Humboldt's writings, was a contribution to scientific orthodoxy. But Darwin had, along the way, acquired an urge to do more than just add his building blocks to the orthodox scientific edifice. He decided to rearrange those blocks of knowledge into a different structure, and for that task neither Humboldt's Personal Narrative nor any other of his works could serve as a model. Humboldt had lacked the confidence which Darwin needed that biogeography and the origin of species could be understood. Humboldt had not explored very far the possible connections between biology and geology. Nor had he provided a general synthetic account of population biology. Had he done so, he might have been more explicit about the extent of his endorsement of Malthus. But even if he had, Humboldt's strong orientation toward cooperation would probably have inhibited his recognition of the importance of competition in nature.Lyell, who had also benefited from reading Humboldt, gave Darwin insights that were lacking in Humboldt's Personal Narrative. Lyell admirably demonstrated how stratigraphy, paleontology, biogeography, and population biology could be interrelated, and his reasons for doing so were essentially the same as Darwin's. Lyell's understanding of biogeography and ecology came from the writings of Augustin-Pyramus de Candolle as much as from Humboldt's, and from the former Lyell derived an appreciation for the importance of competition and also a confidence that the mysteries of biogeography could be explained.¹¹⁷ Furthermore, Lyell's discussion of all these subjects and also of evolution in his Principles of Geology is a good synthetic argument that was the ideal model for Darwin's greatest book.Darwin, having become convinced that species change through time, was able to synthesize in his mind the contributions which he had derived from the writings of Humboldt and Lyell as they applied to the species question. When Darwin wrote his Journal of Researches there were two large gaps in his thinking about evolution that bothered him—the mechanism of evolution and the causes of extinction. It was only after reading Malthus in 1838 that he realized, as Lyell had more or less pointed out, how important was competition in nature. He now had the general outlines for his theory, and in the 1845 abridged edition of his Journal, now retitled The Voyage of the Beagle, he inserted a fuller discussion of competition in nature which showed his awareness of its importance as an ecological factor.¹¹⁸ An abridged version of this paper was presented at the meeting of the History of Science Society in Washington, D.C., on 29 December 1969.     

Assessment of constancy and plasticity of biological rhythms of physiological processes under comfortable and subextreme (high altitude and desert) conditions

A relative constancy of the acrophases of human circadian rhythms of autonomic functions was studied. Quantitative assessment was performed for interdaily, interindividual, intragroup, intraindividual, and total changes in the acrophases of the circadian rhythms of 22 parameters of hemodynamics, heart rate control, thermal status, and salivary electrolyte levels under comfortable environmental conditions and during early adaptation to high-altitude hypoxic and hot desert conditions. A biological interpretation was given for different criteria of changes in the acrophases. Phase-constant and phase-shifting circadian rhythms were determined.     

Another place, another timer: Marine species and the rhythms of life

The marine ecosystem is governed by a multitude of environmental cycles, all of which are linked to the periodical recurrence of the sun or the moon. In accordance with these cycles, marine species exhibit a variety of biological rhythms, ranging from circadian and circatidal rhythms to circalunar and seasonal rhythms. However, our current molecular understanding of biological rhythms and clocks is largely restricted to solar-controlled circadian and seasonal rhythms in land model species. Here, we discuss the first molecular data emerging for circalunar and circatidal rhythms and present selected species suitable for further molecular analyses. We argue that a re-focus on marine species will be crucial to understand the principles, interactions and evolution of rhythms that govern a broad range of eukaryotes, including ourselves.     

Ferdinand Vandeveer Hayden as Naturalist

SYNOPSIS. Like most American naturalists born during the firsthalf of the nineteenth century, Ferdinand Vandeveer Hayden (1829–1887)was fascinated with all living creatures from boyhood, and,like many others, he enriched his early proclivities by studyingmedicine. He worked in Cleveland under J. P. Kirtland and thenin Albany, where he came under the tutelage of James Hall, ofthe Geological Survey of New York. Hall sent him on his firstcollecting trip in the summer of 1853. Showing the independencefor which he became famous, Hayden broke with Hall, however,and with the encouragement of S. F. Baird, and partial sponsorshipfrom the Smithsonian Institution, he spent the remainder ofthe 1850s on a series of exploring and collecting expeditionsto the Upper Missouri River. During the 1860s and 1870s he gainedrenown as a geologist, in particular as director of the Surveyof the Territories, but he never lost his broader interestsin natural history. Both his writings and the unique collectionshe himself made illustrate his catholic curiosity. More importantto natural history were the voluminous publications he sponsoredthrough his Survey, which stimulated specialized research onan encyclopedic range of subjects.     

Complex societies

The complexity of human societies of the past few thousand years rivals that of social insect societies. We hypothesize that two sets of social “instincts” underpin and constrain the evolution of complex societies. One set is ancient and shared with other social primate species, and one is derived and unique to our lineage. The latter evolved by the late Pleistocene, and led to the evolution of institutions of intermediate complexity in acephalous societies. The institutions of complex societies often conflict with our social instincts. The complex societies of the past few thousand years can function only because cultural evolution has created effective “work-arounds” to manage such instincts. We describe a series of work-arounds and use the data on the relative effectiveness of WWII armies to test the work-around hypothesis. Richerson received his Ph.D. degree in zoology from UC Davis in 1969. He is currently a professor in the Department of Environmental Science and Policy. In addition to his work in cultural evolution, he has worked on the limnology of Lake Tahoe and Clear Lake in California, and on Lake Titicaca in Peru and Bolivia. Boyd received his Ph.D. degree in ecology from UC Davis in 1975, though his thesis work was a resource economics problem. He is currently a professor of anthropology at UCLA. His research interests besides cultural evolution are game theory and a small bit of primatology from time to time.     

Clock genes, oscillators, and cellular networks in the suprachiasmatic nuclei

The mammalian SCN contains a biological clock that drives remarkably precise circadian rhythms in vivo and in vitro. Recent advances have revealed molecular and cellular mechanisms required for the generation of these daily rhythms and their synchronization between SCN neurons and to the environmental light cycle. This review of the evidence for a cell-autonomous circadian pacemaker within specialized neurons of the SCN focuses on 6 genes implicated within the pace making mechanism, an additional 4 genes implicated in pathways from the pacemaker, and the intercellular and intracellular mechanisms that synchronize SCN neurons to each other and to solar time.     

Circannual clocks in avian reproduction and migration

Many behavioural and physiological functions of organisms are adjusted to the periodic changes in their environment, particularly to those related to the natural day and year. This adjustment is often achieved through the action of endogenous daily (circadian) and annual (circannual) clocks. Studies of the control of avian moult, migration and reproduction have played a major role in understanding how biological clocks function and interact with rhythms in the environment. Investigations on tropical birds such as the East African subspecies of the Stonechat ( Saxicola torquata axillaris ). and long-distance migrants like the Garden Warbler ( Sylvia borin ). have provided the longest records of circannual rhythms, some of them running for more than 12 years, with periods ranging from about 9 to 13 months. Avian circannual rhythms are organized in a characteristic way for a particular species or population, and cross-breeding experiments have shown that some of the differences found among them are genetically determined. In African Stonechats circannual rhythms guarantee that seasonal events occur at the appropriate times of the year and in the characteristic sequence. They also control a "reproductive window" that provides the temporal framework for breeding. The width of this window is rather inflexible but the performance of a bird within this framework (e.g. whether it breeds once or twice per season) is subject to modification by environmental conditions. In migratory birds circannual programs are involved in determining the time course, distance and direction of migration. Circannual rhythms are synchronized with and modified by environmental factors in a complex way, but the endogenous mechanisms usually respond to environmental cues such that an optimal adjustment to season and latitude is guaranteed.     

Circannual clocks in avian reproduction and migration

Many behavioural and physiological functions of organisms are adjusted to the periodic changes in their environment, particularly to those related to the natural day and year. This adjustment is often achieved through the action of endogenous daily (circadian) and annual (circannual) clocks. Studies of the control of avian moult, migration and reproduction have played a major role in understanding how biological clocks function and interact with rhythms in the environment. Investigations on tropical birds such as the East African subspecies of the Stonechat ( Saxicola torquata axillaris ) and long-distance migrants like the Garden Warbler ( Sylvia boriri ) have provided the longest records of circannual rhythms, some of them running for more than 12 years, with periods ranging from about 9 to 13 months. Avian circannual rhythms are organized in a characteristic way for a particular species or population, and cross-breeding experiments have shown that some of the differences found among them are genetically determined. In African Stonechats circannual rhythms guarantee that seasonal events occur at the appropriate times of the year and in the characteristic sequence. They also control a "reproductive window" that provides the temporal framework for breeding. The width of this window is rather inflexible but the performance of a bird within this framework (e.g. whether it breeds once or twice per season) is subject to modification by environmental conditions. In migratory birds circannual programs are involved in determining the time course, distance and direction of migration. Circannual rhythms are synchronized with and modified by environmental factors in a complex way, but the endogenous mechanisms usually respond to environmental cues such that an optimal adjustment to season and latitude is guaranteed.     

Linnaeus,animals and man*

Linnaeus is often undervalued as a zoologist. His importance lies not only in the introduction of binomial nomenclature and his Systema Naturae. As a systematist he divided the insects into the groups, Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Hymenoptera, Diptera and Aptera. His programme, as expressed in his Methodus in Systema Naturae (1st ed.) is astounding in its biological manysidedness. He was before his time in many respects: he wrote and lectured upon bird migration, biological control of insects with their parasites or predators, protective mimicry, the struggle by all organisms for survival, contagious diseases as well as fermentation due to small living particles. He was the first to call attention to the close relationship between man and the anthropoid apes.