bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Pigmentation of Cavernicolous Animals
Authors: Beatty R. A. 
Published: April 2021

ABSTRACT
Organic detritus was examined from Chislehurst Cave and from the Postumia Grotte (north Italy). The origin of carotenoid material in the detritus was closely associated with the influence of underground rivers. In the Postumia Grotte, large quantities of carotenoid material were present in detritus swept in by the underground river and deposited in a pool. A smaller quantity was present in similar detritus which had been exposed to the air. Very little was found in airborne detritus at the mouth of the cave, exposed to the air, to light and to temperatures higher than those prevailing within the cave. No carotenoid pigments were found in sediment from a drip pool, which was not connected with the underground river. In Chislehurst Cave no carotenoid pigments could be detected in detritus exposed to the air. These observations indicate that the cave fauna must have some access to carotenoid pigments. A carotene (apparently the β-compound) was found, together with free xanthophylls in the cave salamander Proteus. The distribution varied in different parts of the body. No carotenoids were detected in the cave amphipod Niphargus, taken from the drip pool mentioned above. In the carotenoid materials of detritus, xanthophylls predominate. This has been observed by other workers in carotenoid pigments from peat associated with calcium carbonate. The absorption maxima of the xanthophyll isolated by these workers agree closely with the maxima found in the present investigation. An unidentified red pigment with a powerful fluorescence was found in all the detritus samples studied. It was soluble in organic solvents and showed absorption maximum at 457 ± 2μμ in carbon disulphide.
A Study of the Relative Toxicity of Anions, with Polycelis Nigra as Test Animal
Authors: Jones J. R. Erichsen 
Published: April 2021

ABSTRACT
A brief review is given of existing knowledge regarding the physiological effects of anions, and literature dealing with their relative toxicity.
The degree of toxicity of twenty-seven anions to Polycelis nigra (Müller) has been assessed, by determining in each case the molar concentration the animal survives for 48 hr. at 15−18° C.
On this basis their order of increasing toxicity is as follows; commas separate ions of similar degree of toxicity:
Generally speaking anions are very much less toxic than cations. Even the most toxic anion (OH) is far less toxic than ionic copper, silver or gold.
The respiration rate of Polycelis is heavily depressed by cyanide, but the survival time is three days or longer, as long as the respiration rate is not less than about 16 % of the normal value. With further depression the survival time shortens rapidly, and at 9 % normal is under 4 hr.
The normal respiration rate of Polycelis nigra is 0·165 c.c. O2/g./hr. This is not very much less than that of the trout. Polycelis is considerably the more resistant to cyanide. This is probably connected with its capability of surviving very many hours in water containing a very reduced supply of oxygen.
Notes on the Distribution of Pigment Granules in the Retinal Pigment Epithelium of Light- and Dark-Adapted Rana Temporaria, and on the Nature of the Eye Pigment in the Frog and the Ox
Authors: Dawes Ben 
Published: April 2021

ABSTRACT
About two years ago, the writer made a study of the retinal pigment epithelium of twenty-two English frogs which had been subjected to various experimental conditions and found that the dispositions of the pigment granules could not be explained adequately in terms of the oft-described migration which is believed to take place during light- and dark-adaptation of the eye. The results were anomalous, in so far as the amount of pigment present under certain conditions seemed to be greater than at other times.
On the Function of Haemoglobin in Chironomus
Authors: Ewer R. F. 
Published: April 2021

ABSTRACT
At 17° C. the oxygen consumption of Chironomus larvae shows little diminution when the oxygen concentration in the water decreases from 7·5 c.c. per litre (air saturation) to about 3 c.c. per litre. Below 3 c.c. per litre a further decrease in oxygen concentration causes a falling ôff in oxygen consumption. At 17° C. the oxygen consumption of Chironomus larvae whose haemoglobin has been converted to carboxyhaemoglobin is as great as that of normal animals from air saturation down to 3 c.c. per litre. Below this point the oxygen consumption is less than that of normal animals. It follows that at 17° C. the haemoglobin of Chironomus larvae from well aerated water does not function in oxygen transport at air saturation, but only at oxygen pressures below 3 c.c. per litre. Some observations of the habitat of the larvae show that they can live in situations where oxygen concentrations of less than 2 c.c. per litre persist for periods of at least 16 consecutive hours. The larvae are also to be found in situations where the oxygen concentration is high.
On Properties of the Red Cell Ghost
Authors: Ponder Eric 
Published: April 2021

ABSTRACT
This paper is concerned with certain properties of the mammalian red cell ghost. The principal conclusions are:
When red cells are haemolysed by water they increase in volume, changing their shape and becoming spheres. If the degree of hypotonicity is sufficient they haemolyse in the spherical form, but quickly resume the form of disks, even in hypotonic solutions. If the haemolytic systems are rendered isotonic by the addition of salts, the cells shrink temporarily, but finally assume their original volume and shape. It seems that when there are no osmotic forces acting on it, the watery ghosts tend to take up the volume and shape from the red cell from which it was derived. When a red cell haemolyses in a hypotonic medium and becomes a ghost, a considerable amount of haemoglobin is retained, perhaps by adsorption. It is doubtful whether this adsorption could be on a purely surface structure ; to account for the results we might have to postulate an internal structure in addition. After haemolysis by water, red Cells will not form spheres between slide and coverslip, nor by the addition of lecithin. If the watery ghosts are made by precipitation with CO2, no sphering can be observed between slide.and slip, with lecithin, with saponin, or with rose bengal. In the case of the watery ghost, the “form component” seems to be preserved, for the ghosts are biconcave disks; the surface, however, must have been altered, for disk-sphere transformations no longer take place.
The Respiratory Function of the Haemoglobin of the Earthworm1
Authors: Johnson M. L. 
Published: April 2021

ABSTRACT
It was claimed by Davy as early as 1862 that the haemoglobin in the blood of the earthworm has a respiratory function, but subsequent studies have given conflicting results. In the more recent investigations advantage has been taken of the fact that haemoglobin has a greater affinity for carbon monoxide than for oxygen; the oxygen consumption of normal worms is compared with that of worms whose haemoglobin has been put out of action by saturation with carbon monoxide. Using this method, Jordan & Schwarz (1920) concluded that haemoglobin functions as a transporter of oxygen only at low pressures of oxygen (23–30 mm. mercury).2Dolk & van der Paauw (1929) criticized this work on the grounds that the pure carbon monoxide to which the worms were subjected for some hours might have affected the respiratory enzymes as well as the haemoglobin, and that because of individual .variation it was not possible to compare directly the oxygen consumption of normal and carbon monoxide-treated worms. They repeated the work with modifications, and again found that haemoglobin was functional as an oxygen transporter only at low pressures of oxygen, below 57 mm. mercury. Their work was done on narcotized animals, and was therefore criticized by Thomas (1935), who, moreover, considered that the conclusions drawn by Dolk & van der Paauw were not justified by the experimental data they published. Thomas reinvestigated the matter, and came to the conclusion that haemoglobin has no respiratory function at oxygen pressures lower than 114 mm., for the oxygen consumption of normal and carbon monoxide-treated worms was the same. Above 114 mm. oxygen pressure the oxygen uptake of normal worms rose sharply, while that of carbon monoxide-treated worms remained constant, but Thomas did not attribute this difference in behaviour to haemoglobin, and one is left with the impression that in the earthworm haemoglobin is functionless as an oxygen transporter at all pressures of oxygen. Thomas’s results must, however, be accepted with reserve, for he gives data of experiments on only two normal worms and three carbon monoxide-treated worms.
The Biology and Behaviour of Ptinus Tectus Boie. (Coleoptera, Ptinidae), A Pest of Stored Products
Authors: Gunn D. L. , Hopf H. S. 
Published: April 2021

ABSTRACT
The amount of walking about shown by adult Ptinus tectus is not a simple function of temperature. It depends on culture temperature, on whether the temperature is constant or changing and, with changing temperatures, on the speed and direction of change. Thus, at 20° C., about 25 % of animals walk about if the temperature is constant or rising slowly, while about 90 % are active if it is rising fast or falling slowly. None of the temperature-activity curves bear any resemblance to the usual kind of Q10 curve.
For experiments in which the temperature has been constant for a day the temperature-activity curve of Ptinus rises from 3 to 15° Q., then is steady or falling somewhat to 30 or 35° C., and then falls steeply to 40° C. The activity level depends on the temperature at which the animals have been kept during the previous weeks. When the temperature is raised slowly (3·7’5° C. per hour), activity rises steeply up to about io° C., then falls to the level appropriate to constant temperatures and, at about 30° C., rises steeply again. When the temperature is raised more quickly (14° C. per hour) the activity rise is at first similar to that for slowly rising temperature, but it continues until 90–100 % activity is reached at about 15° C. ; activity remains at this high level until damaging changes occur at about 40° C. When the temperature is slowly lowered, the activity curve is similar to that for quickly rising temperature. There is thus a stimulating effect of change of temperature—whether rising or falling—the magnitude of which depends on the speed and direction of the change.
The results obtained have a considerable bearing on the testing arid use of insecticides whose effectiveness depends on the activity of the insects.
The Biology and Behaviour of Ptinus Tectus Bole. (Coleoptera, Ptinidae), A Pest of Stored Products
Authors: Ewer D. W. , Ewer R. F. 
Published: April 2021

ABSTRACT
At 70 % R.H. development of Ptinus tectus from egg laying to emergence from the cocoon is minimal at 23 – 25° C. and takes an average of about 62 days; at 15° C. the time taken is about 130 days. The minimum temperature at which complete development can occur is below 10° C. and the maximum is between 28 and 30 ° C. ; considerable mortality occurs in eggs and larvae at 28 ° C. and the eggs require a humidity of 100 % R.H. for hatching at this temperature.
At 75 % R.H. and above it is difficult to prevent moulds growing on the food of Ptinus. It appears that 70 % R.H. is a satisfactory humidity for all developmental stages, but in air drier than this (at 25 ° C.Jboth eggs and larvae show an increased mortality and a prolonged development. The hatching of the egg, rather than embryonic development, seems to be sensitive to low humidity.
Adults given food but not water live longer at 70 % R.H. (27° C.) and at 90 % R.H. (15° C.) than at lower humidities. At 25 ° C., below 70 % R.H. feeding is much reduced if water to drink is not given ; at 34 % there is little feeding even when free water is available. Larval feeding is also reduced at low humidities. Oviposition soon ceases unless drinking water is available, at any rate at low humidities.
Ptinus tectus is thus adapted to a temperate climate with a high humidity.
The Ultrastructure And Formation Of Iron Granules In The Honeybee (Apis Mellifera)
Authors: Hsu Chin-Yuan , Li Chia-Wei 
Published: April 2021

ABSTRACT
The honeybee is one of the few organisms that can deposit iron minerals intracellularly. Numerous iron granules are formed in the trophocytes, which are located in the abdomen, beginning on the second day after eclosion. The sequential events of iron deposition in honeybees have been determined and the special features of this biomineralization system are (1) that iron deposition vesicles (IDVs) enlarge by fusing with one another; (2) that dense particles (approx. 7.5nm in diameter) are the basic building blocks in the formation of iron granules; and (3) that a cloudy layer just beneath the membrane of IDVs may play an important role in the formation of the dense particles. The iron granules seem to be randomly distributed in the trophocytes of the worker and drone. In the queen, however, they are clustered and peripherally located. This distinct difference in the iron granule distribution between members of the hive suggests that these iron granules may have some biological functions. A detailed analysis of total iron content during the life cycle of honeybees has shown that iron granules in the adult worker contain approximately 1% of the total iron content and also account for approximately 3% of the increase in iron content that occurs between the newly eclosed worker stage and the adult worker stage.
Anoxic Depression of Spontaneous Locomotor Activity in Crucian Carp Quantified by A Computerized Imaging Technique
Authors: Nilsson Göran E. , Rosén Peter , Johansson Dan 
Published: April 2021

ABSTRACT
The crucian carp (Carassius carassius L.) is one of the most anoxia-tolerant fishes. An important strategy used by the crucian carp to survive anoxia is to lower its rate of energy consumption. Anoxia-tolerant fish are known to utilize simultaneously two different strategies for reducing energy consumption during anoxia, the first being a reduction in locomotor activity and the second being a depression of cellular energy demands. Nevertheless, the reduction in locomotor activity during anoxia has never been measured quantitatively. This lack of information is apparently because technical problems have prevented the measurement of spontaneous locomotor activity in fish. It is now possible to use computerized video-imaging techniques to record the movement of an animal continuously. By the use of such a technique, we show that crucian carp respond to anoxia (330min at 9°C) by rapidly decreasing their locomotor activity (spontaneous swimming distance) to about 50% of that displayed during normoxia. Frequency diagrams of spontaneous swimming speed showed no bimodality and indicated a general decrease in swimming speed from a median value of 1.82 m min−1 during normoxia to 0.82 m min−1 during anoxia. It is tentatively estimated that the anoxic depression of locomotor activity corresponds to a 35–40% reduction in total energy consumption. The role of locomotor activity in fish energy budgets is discussed.
Determination of the Constants of the Henderson–Hasselbalch Equation, αCO2 and pKa, in Sea Turtle Plasma
Authors: Stabenau Erich K. , Heming Thomas A. 
Published: April 2021

ABSTRACT
Hydration of CO2 yields HCO3−via the reaction: Acid–base physiologists traditionally simplify the reaction by omitting the H2CO3 term and lumping all ionic CO2 species into the HCO3− term. The simplified reaction forms the basis for the familiar Henderson–Hasselbalch equation of the CO2–HCO3− buffer system: where αCO2 is the solubility coefficient relating [CO2] and (Henry’s Law). The apparent pK (pKa) in this equation lacks a rigorous thermodynamic definition. Instead, it is an empirical factor relating pH, the product of αCO2 and and the apparent [HCO3−] (i.e. the sum of all ionic CO2 species).
Pre- and Postbranchial Carbon Dioxide Content of Rainbow Trout (Oncorhynchus Mykiss) Blood After Catecholamine Injection
Authors: Nikinmaa Mikko , Vihersaari Laila 
Published: April 2021

ABSTRACT
It is generally accepted that plasma bicarbonate is the major source of carbon dioxide excreted in the gills of teleost fish (Perry, 1986). Although anion exchange across the membrane of rainbow trout erythrocytes is rapid, with a half-time of 0.8s for chloride equilibration at 15°C (Romano and Passow, 1984), the rate of bicarbonate influx into the erythrocytes limits the rate of conversion of plasma bicarbonate to carbon dioxide and, thereby, carbon dioxide excretion per unit volume of blood in gills, because the residence time of blood in the secondary lamellae of the gills is only 1–6s (Hughes et al. 1981; Bhargava et al. 1992). Thus, factors that reduce the net rate of bicarbonate influx through the anion exchanger may reduce the efficiency of carbon dioxide excretion in gills. The effect is, however, temporary. If carbon dioxide production remains constant, the reduction of carbon dioxide excretion will increase the venous carbon dioxide tension and content, thus increasing the diffusion gradient across the gills and speeding up CO2 removal until the CO2 excretion again matches production.
Anatomical and Physiological Identification of Inhibitors of the Motor Giant and Segmental Giant Neurones In The Crayfish
Authors: Fraser K. , Heitler W. J. 
Published: April 2021

ABSTRACT
We anatomically and physiologically identify four interneurones which inhibit the motor giant neurone (MoG) and an interneurone which inhibits both the MoG and the segmental giant (SG) neurone of crayfish. We term these the MoG-I1, -I2, -I3, -I4 and MoG/SG-I neurones. MoG-I1 is almost always very strongly dye-coupled to its bilateral homologue. It is one of the interneurones mediating recurrent feedforward inhibition from the giant fibres (GFs) to the MoG. The GFs activate MoG-I1 by a disynaptic path through the SGs (GF → SG → MoG-I1), which is entirely mediated by rectifying electrical synapses. The resulting trisynaptic path (i.e. GF → SG → MoG-I1 → MoG), in which the first two synapses are electrical, ensures reliable and constant short-latency inhibition of the MoGs following their monosynaptic electrical activation by the GFs (GF → MoG). The remaining MoG-Is receive input from the GFs and other sources through unidentified polysynaptic pathways.
Each interneurone inhibits the MoG and/or SG through depolarising IPSPs, which can be as large as 25mV in amplitude. These IPSPs can effectively block transmission from the GFs to the MoG. The unique morphology of the MoG allows the inhibitory connections from the MoG-Is to be visualised at the light microscope level following staining with Lucifer Yellow. The MoG-Is project a high-density cobweb-like network of fine synaptic branches over the surface of the MoG, which spread from the region of the electrical input from the GFs within the connectives, across the expanded integrating region of the MoG, and onto its axon in the proximal region of the third root. The extensiveness of this anatomical connection correlates well with the high effectiveness of the inhibition mediated by some of the MoG-Is.
Visual Control of Velocity of Approach by Pigeons When Landing
Authors: Lee David N. , Davies Mark N. O. , Green Patrick R. , (Ruud) Van Der Weel F. R. 
Published: April 2021

ABSTRACT
Films of pigeons flying to a perch were analysed to test a theory of how speed of approach and timing of foot extension in preparation for landing are visually controlled. Rapid neural computation of distance to perch and of speed and deceleration would seem to be required. However, according to the theory, none of this is necessary. Simpler control is possible based solely on the value of the tau function of certain optic variables x, where the tau function of x is x divided by its rate of change; i.e. is a first-order approximation of time to contact with the perch and so could be used for timing foot extension. Controlled braking is possible by simply keeping , the rate of change of τ(x), constant. The results indicated that pigeons did regulate their braking when approaching the perch by keeping constant and initiated foot extension when τ(x) reached a threshold value of approximately 150ms. They followed this procedure even when they had one eye covered, and so binocular vision was not necessary for regulating braking or timing foot extension. It is shown that an optic variable that the pigeons could be using is the width of the optic projection of the gap between foot and perch. It is further shown that they could be using the same optic variable for controlling the trajectory of their feet to contact the perch.
Stanniectomy Increases Renal Magnesium and Calcium Excretion in Freshwater North American Eels (Anguilla Rostrata)
Authors: Butler David G. 
Published: April 2021

ABSTRACT
The corpuscles of Stannius are linked to the renal transport of magnesium in freshwater North American eels. The urinary magnesium concentration and rate of magnesium excretion increased 3 days after the corpuscles had been removed, a trend which continued throughout a 14 day observation period. There was no overall change in urine flow rates except for a brief 50% reduction 2 days after stanniectomy. Plasma magnesium concentrations drifted downward after stanniectomy. In contrast, plasma calcium concentrations increased significantly within 2 days following stanniectomy and they continued to increase thereafter. Urinary calcium concentrations and the rate of urinary calcium excretion increased 7 days after stanniectomy, implying that the renal response was subject to the increase in plasma calcium concentration: the urine/plasma calcium ratio remained constant. Even though the urinary calcium concentration increased after stanniectomy, the increase in urinary magnesium concentration was proportionally greater.
Hormonal Control of Transmitter Plasticity in Insect Peptidergic Neurons: I. Steroid Regulation of the Decline in Cardioacceleratory Peptide 2 (Cap2) Expression
Authors: Loi P. K. , Tublitz N. J. 
Published: April 2021

ABSTRACT
Transmitter plasticity, the ability to alter transmitter expression, has been documented in several different preparations both in vivo and in vitro. One of these is the tobacco hawkmoth, Manduca sexta, whose central nervous system contains four individually identified lateral neurosecretory cells (LNCs) that undergo a postembryonic transmitter switch in vivo. In larvae, the LNCs express high levels of a myoregulatory peptide, cardioacceleratory peptide 2 (CAP2). In contrast, the predominant LNC transmitter in adult moths is bursicon, a classic insect peptide hormone responsible for cuticular tanning. Here we show that the CAP2-to-bursicon conversion by the LNCs is a multi-step process beginning with a decline in CAP2 levels midway through the final larval stage. We provide several lines of evidence that this CAP2 drop is regulated by the insect steroid hormone 20-hydroxyecdysone (20-HE). The LNCs exhibit a fall in CAP2 levels at the beginning of metamorphosis, immediately after the commitment pulse of 20-HE when steroid levels are elevated. LNCs not exposed to this 20-HE rise do not exhibit a decline in CAP2 level. The transmitter switch can also be prevented by using an analog of juvenile hormone to create a larval hormonal environment during the commitment pulse of 20-HE. The CAP2 decline in the LNCs could be directly induced by exogenous steroid application, but only under conditions where the LNCs remained connected to the brain. Thus, the first step in the transmitter switch by the LNCs, the decline in CAP2 levels, is triggered by the commitment pulse of 20-HE, which may act indirectly through a set of steroid-sensitive cells in the brain.