An investigation into the diurnal variation of the body temperature of nocturnal and other birds, and a few mammals

A quantitative interspecies comparison of the respiratory mucociliary clearance mechanism

Collectively coordinated ciliary activity propels the airway mucus, which lines the luminal surface of the vertebrate respiratory system, in cranial direction. Our contemporary understanding on how the quantitative characteristics of the metachronal wave field determines the resulting mucociliary transport is still limited, partly due to the sparse availability of quantitative observational data. We employed high-speed video reflection microscopy to image and quantitatively characterize the metachronal wave field as well as the mucociliary transport in excised bovine, porcine, ovine, lapine, turkey and ostrich samples. Image processing techniques were used to determine the ciliary beating frequency (CBF), the velocity and wavelength of the metachronal wave and the mucociliary transport velocity. The transport direction was found to strongly correlate with the mean wave propagation direction in all six species. The CBF yielded similar values (10–15 Hz) for all six species. Birds were found to exhibit higher transport speeds (130–260 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu$$\end{document}μm/s) than mammals (20–80 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu$$\end{document}μm/s). While the average transport direction significantly deviates from the tracheal long axis in mammals, no significant deviation was found in birds. The metachronal waves were found to propagate at about 4–8 times the speed of mucociliary transport in mammals, whereas in birds they propagate at about the transport speed. The mucociliary transport in birds is fast and roughly follows the TLA, whereas the transport is slower and proceeds along a left-handed spiral in mammals. The longer wavelengths and the lower ratio between the metachronal wave speed and the mucociliary transport speed provide evidence that the mucociliary clearance mechanism operates differently in birds than in mammals.

Sweating Out the Circadian Rhythm: A Technical Review

Circadian dysfunction or dysregulation is associated with many chronic morbidities. Current state-of-art technologies do not provide an accurate estimation of the extent of disease affliction. Recent advances call for using wearables for improving management and diagnosis of circadian related disorders. Sweat contains an abundance of relevant biomarkers like cortisol, DHEA, and so forth, which could be leveraged toward tracking the user's chronobiology. In this article, we provide a review of the key developments in the field of wearable sensors for circadian technologies. We highlight the value of using sweat along with portable electronics toward developing state-of-the-art platforms for efficient diagnosis and management of chronic conditions. Finally, we discuss challenges and opportunities for using wearable sweat sensors for circadian diagnosis and disease management.

Sex-biased parasitism in vector-borne disease: Vector preference?

Sex-biased infections are a recurrent observation in vertebrates. In many species, males are more parasitized than females. Two potentially complementary mechanisms are often suggested to explain this pattern: sexual differences in susceptibility mainly caused by the effect of sex hormones on immunity and differential exposure to parasites. Exposure is mostly a consequence of host behavioural traits, but vector-borne parasitic infections involve another degree of complexity due to the active role of vectors in transmission. Blood-sucking insects may make choices based on cues produced by hosts. Regarding malaria, several studies highlighted a male-biased infection by Plasmodium sp in great tits (Parus major). We hypothesize that the mosquito vector, Culex pipiens, might at least partially cause this bias by being more attracted to male birds. Intrinsic variation associated to bird sex would explain a preference of mosquitoes for males. To test this hypothesis, we provide uninfected mosquitoes with a choice between uninfected male and female nestlings. Mosquito choice is assessed by sex typing of the ingested blood. We did not observe any preference for a given sex. This result does not support our prediction of a preference of mosquitoes for male great tits during the nestling period. In conclusion, mosquitoes do not seem to have an intrinsic preference for male nestlings. However, sexually divergent traits (e.g. behaviour, odour, metabolic rate) present in adults may play a role in the attraction of mosquitoes and should be investigated.

V.—Observations on the Body Temperature of some Diving and Swimming Birds

Observations were made on the body temperature of a large number of diving and swimming birds of eighteen different species in the Orkney Islands and Firth of Forth, Scotland, and on and around Cayuga Lake, N.Y., U.S.A., immediately after they were killed by shooting.

1. In all the species examined, where the sex was determined, it was found that the rectal temperature of the male was slightly below that of the female.

2. Of the orders examined the highest temperatures were found in the Longipennes and the lowest in the Tubinares. When arranged according to body temperature the series does not run parallel with the zoological series.

In conclusion, I wish to express my indebtedness to Dr H. D. Reed and Dr A. H. Wright for help in identifying the specimens obtained from Cayuga Lake and the surrounding district.

XI.—An Investigation into the Effects of Seasonal Changes on Body Temperature

Monthly observations, extending over one year, were made on the rectal temperature of 114 domestic fowls (Gallus gallus, ♀) and records from forty-one of these were obtained for two years. Six different breeds were used, each located in a separate pen, all under similar conditions, and the mean temperatures for each group were plotted out to form an annual temperature curve. It was found that—

1. The lowest temperatures occur in December, January, and February, and the highest in June, July, and August, corresponding in a general way with the temperature of the external air.

2. Barometric pressure does not appear to have any influence on the body temperature of the hen.

3. The curve of egg-production does not coincide with the annual temperature curve, the former reaching its highest level in April and May, the latter in June, July, and August.

If we compare the mean rectal temperature at two periods of the year when the external or weather conditions are approximately the same (April-May and September-October), but when the vitality of the birds, as indicated by the curve of egg-production, moulting, etc., is at a maximum and minimum respectively, we find that the figures are practically identical. This would seem to show that cyclical bodily changes have little effect on body temperature as compared with outside influences.

The influence of the sex-hormone testosterone on body temperature and metabolism of the male Japanese quail (Coturnix coturnix japonica)

Testosterone causes a significant body temperature decrease in male quails. Oxygen consumption/g b. wt remains the same, however.

Metabolic rate: its circadian rhythmicity in the female domestic fowl

1. In quasi-natural cyclic lighting, a circadian rhythm was observed in seven fowls; the range of oscillation of the rhythm was 50% of the mean metabolic level. Little variation was present between the individuals. 2. In fowls maintained for 15 days in isolation under 700 lx (ten fowls) or 0.07 lx (four fowls) constant lighting and at constant temperature free-running rhythms were evident; the range of oscillation was about 12% of the mean level. Large variation prevailed between the individuals in the range of oscillation and in the portion of variance accounted for by periodic regression. In dim light, rhythmicity declined to become non-significant by 8 days of exposure. 3. In four fowls maintained in a 6L/6D regimen for 12 days, metabolic rate was entrained to an ahemeral rhythm; there was no evidence of circadian influence on the metabolic response to light. Little variation was present between the individuals. Rhythmicity was maintained over the experimental period. 4. Metabolic levels were similar on 0.07 lx, 700 lx constant light, during the dark phase of the 6L/6D regimen and during night time in the quasi-natural cyclic lighting. They were also similar on the light phase of the 6L/6D regimen and the quasi-natural lighting.

The effect of photoperiod on the deep body temperature of domestic turkeys and its relationship to the diurnal periodicity of Leucocytozoon smithi gametocytes in the peripheral blood of turkeys

Eighteen turkeys naturally infected with Leucocytozoon smithi were separated into 3 groups of 6 each and were respectively exposed to conditions of natural, reversed, or continuous light. Turkey deep body temperature and peripheral gametocyte numbers of L. smithi in all three groups were determined every 2 hr over a 36-hr period. The peak period of both turkey body temperature and gametocyte numbers coincided with the midpoint of the light period for turkeys exposed to natural and reversed light conditions. The body temperature of turkeys exposed to continuous light remained relatively constant while L. smithi gametocytes exhibited asynchronous behavior.

Different sensitivities of avian- and mammalian-haemoglobin synthesis to elevated temperatures

Avian- and mammalian-haemoglobin synthesis show different sensitivities to elevated temperatures. Temperature-dependent, reversible polyribosome disaggregation in avian cells occurs only at 45 degrees C, which is 3 degrees higher than the temperature for mammalian cells, and seems to be due to a block in the initiation of new polypeptide chains. The implications of these findings are discussed.