Studies on hemolymph nodes. I. Histology of the renal hemolymph node of the rat

The structure of the left renal hemolymph node of young adult male Swiss albino rats has been studied by optical microscopy of semithin plastic embedded sections. Afferent lymphatics were found, opening into the subcapsular sinus through valved ostia, in a large majority of nodes. Free erythrocytes were found in the afferent lymphatics and in the subcapsular sinus. In the intermediary and medullary sinuses, erythrocytes were mostly attached to sinus macrophages. The efferent lymphatics contained few erythrocytes. All the sinuses macrophages. The efferent lymphatics contained few erythrocytes. All the sinuses contained a stained precipitate of lymph protein. The node is hypoactive in its general form but does not differ essentially from typical lymph nodes, except that it receives, through its afferent lymphatics, lymph containing numerous erythrocytes.

The effect of ambient chloride concentration changes on branchial chloride-bicarbonate exchanges and hemolymph acid-base balance of crayfish

In crayfish Astacus leptodactylus maintained in 13 degrees C ambient water of constant oxygenation and acid-base balance, water chloride concentration was varied while the concentration of other ions, except sulfate, were maintained at constant values. The effects of wide variations of the ambient Cl- concentration, CCl, on the branchial titration alkalinity, delta TA, on delta CCl, delta CCO2, delta CO2 between inspired and expired water, and on the prebranchial hemolymph CCl and pH were studied. The branchial changes of TA, CCl and CCO2 were dependent on the ambient CCl, and a decrease of CCl led to a fall of CO2 excretion. Hemolymph acid-base balance closely depended on ambient CCl, particularly when CCl was less than 1 meq . L-1; when ambient CCl fell from 1 meq . L-1 to 0.1 meq . L -1, pH increased from 7.87 to 8.30. Since hemolymph PCO2 was not affected by the variations of CCl, the changes of pH are mainly explained by the concomitant changes of the hemolymph HCO3- and CO32- concentrations. During an 18-day exposure of crayfish to dechlorinated water, hemolymph CCl decreased progressively whereas its pH increased. The extreme values for CCl were 193 meq . L-1 at day 1 and 96 meq . L -1 at day 18, and the corresponding pH extremes were 7.87 and 8.65. Since the observed modifications of the branchial exchanges and the hemolymph acid-base balance were not related to the small changes of ambient osmolarity or of the SO42- or Na+ concentrations, it is inferred that they depended on a modified Cl-/HCO3- exchange mechanism in the gills.

Effects of hemolymph from immune and non-immune larvae of Galleria mellonella on the ultra-structure of Pseudomonas aeruginosa

The ultrastructure of Pseudomonas aeruginosa, a pathogen of Galleria mellonella is rapidly altered after in vitro exposure to the hemolymph of vaccinated larvae. The bacteria were treated with normal and immune hemolymph for periods of time ranging from 7 to 28 min at 28 degrees C. In contrast to the apparent non-damaging effects of normal hemolymph, the immune hemolymph caused progressive damage to the cells within 7 min. The initial attack was directed towards the cell wall. Complete degradation was observed after 14 to 28 min exposure to the immune hemolymph.

Function-related structural characters and their modifications in the hindgut epithelium of two terrestrial isopods, Armadillidium vulgare and Oniscus asellus

Intercellular junctions of the hindgut epithelial cells of two terrestrial isopods, Armadillidium vulgare and Oniscus asellus, are described. Long septate desmosomes occupy the subluminal region while gap junctions, zonulae adherens and intercellular spaces characterize the remainder of the convoluted lateral cell borders. The specialized junctional complexes and the ultrastructural morphology of the cells indicate that the terrestrial isopod hindgut epithelium functions in transport. Using mitochondrial morphometry as an indicator of cell transport activity, it appears that the posterior hindgut of A. vulgare also participates in osmoregulation, which is not the case with O. asellus. With increased desiccation there develops a significant difference between the mitochondrial structure of the two species. The mitochondria of the former retain the active structural condition (intermediate condensed conformation) while those of the latter become swollen and damaged.

Haemolymph pressure regulation in Porcellio laevis Latr. (Porcellionidae, Isopoda)

Hydrostatic pressure in the haemocoele in Porcellio laevis adults ranges between 3.69 to 12.92 mm Hg (50 to 175 mm H2O). Mechanism involved in haemolymph pressure regulation includes characteristic contractions of intersegmental body musculature. The effects of temperature, humidity, decapitation, destruction of thoracic ganglion, and the injection of insect Ringer and eserine into the haemocoele on intersegmental muscular contractions were studied. The significance of these findings is discussed.

Non-equilibrium acid-base status in C. productus: role of exoskeletal carbonate buffers

Hemolymph acid-base variables (pH, PCO2 and CCO2), hemolymph Ca2+ and Na+ concentrations, and osmolality were measured in unrestrained crabs, Cancer productus, before, during and following 4 hr emersion and 43 hr hyperoxia (460-510 Torr), both at 10 degrees C. Emersion and hyperoxia provoked an acidosis associated with elevation of hemolymph CCO2 and PCO2, yet attempts to calculate PCO2 from measured pH and CCO2 always resulted in values greater than those measured directly. This discrepancy between measured and calculated PCO2, was associated with base excess, and was eliminated upon in vitro equilibration of the hemolymph and more slowly in vivo, suggesting that metabolic compensation for the acidosis occurred more rapidly than could acid-base equilibration. During emersion, increases of CCO2 and [Ca2+] provide evidence that the internal CaCO3 stores, possibly from the exoskeleton, were mobilized during acid-base compensation. Hyperoxia provoked no such increase in Ca2+, and branchial uptake of HCO3- may make a major contribution to the elevation of CCO2 during hyperoxia. It is suggested that shell buffering by aquatic crustaceans provides a means of compensation for acidosis under conditions during which branchial function is impaired.

Neural factors in the regulation of oxygen consumption rhythm in the tissues of the scorpion, Heterometrus fulvipes (C. Koch)

Circadian variation in the effect of cephalothoracic nerve mass (CTNM) extract and blood of the oxygen consumption of the isolated hepatopancreas of the scorpion, Heterometrus fulvipes, was studied. Both CTNM extract and blood from 2000 animal cause maximum increase in oxygen consumption. Another maximum increase was also noted at 0800. It is inferred that a chemical factor from the CTNM is responsible for the observed changes in oxygen consumption of hepatopancreas.

Hemolymph acid-base balance of the crayfish Astacus leptodactylus as a function of the oxygenation and the acid-base balance of the ambient water

The acid-base balance of the prebranchial hemolymph of the crayfish Astacus leptodactylus was studied at various acid-base balances and levels of oxygenation of the ambient water at 13 degrees C. The water acid-base balance was controlled automatically by a pH-CO2-stat. Into water of constant titration alkalinity, TA, this device intermittenly injects carbon dioxide to maintain the pH at a preset value. Water pH was reduced to the same value either by hypercapnia (at constant TA) or by adding HCl or H2SO4 to decrease the TA (at constant CO2 tension). Decrease of hemolymph pH and increase of hemolymph PCO2 were similar for the three acidic waters. Water oxygenation changes strongly affected hemolymph ABB. In crayfish living in hyperoxic water (PO2 congruent to 600 Torr) compared to those in hypoxic water (PO2 congruent to 40 Torr), hemolymph pH was 0.3 to 0.4 unit lower and hemolymph PCO2 several times higher, the exact values of pH and PCO2 depending on the controlled ambient acid-base balance. In any study of the hemolymph acid-base balance of the crayfish, it is an important to control ambient water's acid-base balance and oxygenation as it is to control its temperature, a conclusion which probably holds true for studies on all water breathers.

Regulation of body volume by salivation in a tick challenged with fluid loads

Injection into the hemolymph of 1.2% NaCl, 11.2% sucrose, 2.3% urea (all approximately isosmotic to hemolymph), or distilled water induced salivary fluid secretion in the ixodid tick Amblyomma hebraeum Koch. Saline gave the largest response at high doses. Injection of hyperosmotic NaCL into the hemolymph did not induce salivation but led to the drinking of distilled water in amounts sufficient to dilute the salt load to isosmolarity. Atropine only partially inhibited salivation induced by NaCl, sucrose, and distilled water. Reserpine markedly inhibited salivation induced by NaCl. We propose that at least two sensory pathways (one cholinergic, one not) converge on the secretory nerve. The physiological significance of the cholinergic pathway is not known. The other pathway probably mediates the regulation of hemolymph volume, possibly via stretch receptors, but its transmitter is not known.

[Coagulation of hemolymph in Crustacea. Electrophoretic demonstration of a plasmatic component in the course of hemostasis in a group A crustacean (Cancer pagurus)]

Coagulation assays in vitro of plasmatic extract from Cancer pagurus reveal the existence of a plasmatic coagulation in this species which was considered as yet as lacking a such process. Electrophoretical analysis of this extract before and after coagulation shows the presence of a plasmatic component probably involved in the formation of the clot.

Hormonal regulation of osmotic and ionic balance in the haemolymph of the larvae of dragonfly, Aeschna cyanea (Müller) (Odonata : Aeschnidae)

The present studies provide an evidence of an active involvement of the neurosecretory A cells of the thoracic ganglia in both, the internal hypo- and hyperosmotic regulation in the larvae of Aeschna cyanea.

Blood acid-base state at a variable temperature. A graphical representation

When blood temperature is changed in closed system ('anaerobic') conditions, plasma pH and PCO2 vary but no titration by external CO2, acid or alkaline equivalents takes place. It is therefore assumed that the overall acid-base state undergoes no fundamental change. This is further justified by the constancy of osmotic relationships between plasma and red cells, and to a lesser extent of relative alkalinity and protein alpha imidazole (Reeves, 1972, 1976a, b). These considerations serve as a basis for a correction procedure of pH and PCO2 of blood in open systems in vivo to a standard temperature T* (25 degrees C, eventually 37 degrees C). The temperature-corrected values pH* and P*CO2, and the derived [HCO3]* can be represented on a temperature-independent bicarbonate-pH diagram. This permits an easier interpretation of blood acid-base changes occurring together with body temperature variations, such as in ectotherms, hibernators or in artificial hypothermia. Extension to intracellular pH is considered.

Variations in macromolecular antifreeze levels in larvae of the darkling beetle, Meracantha contracta

Overwintering larvae of the darkling beetle, Meracantha contracta, produce a macromolecular antifreeze that is similar in activity to the glycoproteinaceous and proteinaceous antifreezes found in some cold-water, marine teleost fishes. The antifreeze is not present in the hemolymph of the Meracantha larvae in summer, but its production begins by late September in the wild population. The antifreeze reaches a maximum concentration in February, decreases slowly through spring, and disappears by early June. The supercooling points of the larvae are lowest in February, when the antifreeze levels are highest, and increase as the antifreeze concentrations in the hemolymph decrease in the spring. Larvae collected in mid-February and warm-acclimated lost the antifreeze with-in 12 days. Larvae collected in early September and cold-acclimated required nearly two months to produce concentrations of antifreeze comparable to those of overwintering larvae. Temperature seems to be the major environmental factor responsible for the control of antifreeze levels in Meracantha; however, other environmental factors may also be involved.

[Hemolymph coagulation in Macropipus puber (L.) Crustacea Decapoda. Respective roles of hemolymph and plasma]

The process of coagulation of the hemolymph in Macropipus puber (L.) Crustacea Decapod depends on one or several plasmatic factors and on a thermo-labile cellular factor which does not seem to be specific. The existence of these factors has been demonstrated.

The hormonal control of diuresis in the cabbage white butterfly Pieris brassicae

The diuresis which follows the pupal-adult ecdysis of Pieris brassicae is hormonally controlled. Use of the isolated Malpighian tubules as a bioassay shows the presence of substantial diuretic activity in homogenates of the brain and corpus cardiacum-corpus allatum complex. The hormone is probably produced in the brain and released from a storage site in the corpora cardiaca. The tubules of the butterfly are maximally responsive to the diuretic hormone at the time of eclosion.

[Studies on the rectal pads of the honey bee Apis mellifca]

According to earlier investigations young bees show a rectal fluid hypo-osmotic to the haemolymph. It had been assumed, however, that in certain situations honey bees have to be economical with water and simultaneously form a rectal fluid hyperosmotic to the haemolymph. The latter has been confirmed by the present investigation.

The influence of various factors on fluid secretion by in vitro salivary glands of ixodid Ticks

1. Salivary glands of the female ixodid tick, Dermacentor andersoni, secrete fluid in vitro when bathed in a slightly modified version of the mammalian tissue culture medium ‘TC 199′. 2. Rate of salivation in vitro increases with progression of feeding, but there is no comparable increase in dry weight of the salivary glands during the early phase of engorgement. Engorged ticks secreted at only 25% the rate of 90–250 mg ticks, indicating that salivary gland degeneration has already begun in the very early post-engorgement stage. 3. A salivary gland stimulating factor can be detected in the nervous system but not in other tissues. 4. Male salivary glands secrete at only 1/20th the rate of female glands. Thus males probably do not use their salivary glands as osmoregulatory organs. 5. From the uniform lack of response to ACh and uniform response to DA in 7 ixodid tick species, it is suggested that the control of salivation is similar throughout the ixodid family.

The receptive fields of Daphnia ommatidia

1. The focal length and positions of the principal planes of an isolated Daphnia lens were determined, and the refractive index of the rhabdom was measured. 2. The lens can form an image, but this always lies well behind the rhabdom. This was confirmed by direct observation of images inside a clear-eye mutant Daphnia eye. 3. The rhabdom was shown to be unlikely to function as a waveguide, and a ray optics model is proposed to enable the prediction of ommatidial receptive fields from the lens data. 4. The predicted receptive fields have wide plateaus and steep sides, and there are virtually no totally blind gaps between neighbouring ommatidia.

Sodium extrusion by the sea-water-acclimated fiddler crab Uca pugilator: comparison with other marine crustacea and marine teleost fish

1. Measurements of the blood Na concentration and transepithelial electrical potential (T.E.P.) across Uca pugilator acclimated to sea water indicate that Na is maintained out of electrochemical equilibrium with sea water. The resulting net Na influx as well as the sodium gain due to ingestion of the medium must be balanced by extrarenal Na extrusion. 2. The small T.E.P. (−0.7 mV) and the ‘transport numbers’ of Na and Cl indicate that the permeability to these ions is equivalent. 3. Removal of external K results in a significant stimulation of unidirectional Na efflux that is dependent upon external Na but is not inhibited by ouabain. 4. Transfer of Uca to K and Na-free sea water results in a 54% decline in unidirectional efflux, which is not due to T.E.P. changes. Readdition of 25mM-K stimulates Na efflux much more than can be accounted for by changes in the T.E.P. Readdition of 25mM-Na to potassium-free sea water does not change the Na efflux. 5. The results indicate that Na extrusion by Uca is via a Na/K exchange mechanism which partially inhibits Na/Na exchange. Cessation of Na/K exchange (in K-free sea water) removes this inhibition and allows rapid Na/Na exchange. It is not known whether Na/K and Na/Na exchange are via the same or parallel carrier systems.

Coagulocyte alterations in clotting hemolymph of Carausius morosus L

1. The structural changes in the coagulocytes of Carausius morosus during hemolymph coagulation in vitro have been studied under the PCM and in the TEM. 2. In agreement with former PCM observations on Carausius morosus, the coagulocytes are the only hemocytes to induce coagulation of the plasma. Immediately or after a few seconds upon withdrawal of the hemolymph, their structural changes consist of a considerable enlargement of the perinuclear cysterna and of direct ejection into the plasma of nuclear and cytoplasmic substances through microruptures of the cytoplasmic membrane. The other categories of hemocytes do not contribute to the plasma coagulation. Their structural alterations take place without breakage of the cytoplasmic membrane when the plasma reactions are already established. 4. These plasma reactions appear in the form of circular islands of granular material around the coagulocytes, of extension of the coagulum in the channels between the islands and of transformation of the clot into a network of threads. 5. As reported in other studies in the TEM, no specific organelle characteristic of the coagulocyte ultrastructure could be found in the coagulocytes of Carausius. 6. Owing to the absence of any specific structural criterion of identification, the results suggest that the functional difference between coagulocytes and the other categories of hemocytes as regards coagulation of the plasma might be caused in part by differences of permeability of the cell membranes.

The influence of hemolymph-binding protein on juvenile hormone stability and distribution in Manduca sexta fat body and imaginal discs in vitro

The wing discs and fat body of Manduca sexta larvae contain enzymes (i.e. carboxylesterase and epoxide hydratase) that can convert the C18 juvenile hormone (JH) to the acid, diol and acid diol. No evidence of oxidative degradation was noted. In vitro studies suggest that JH can be compartmentalized within the cells of the fat body where it is less accessible to degradative mechanisms. Experiments utilizing a hemolymph-binding protein fraction (BPF) in vitro with fat body and imaginal discs indicate that the BPF retards the uptake of JH by tissues and its subsequent degradation by tissue enzymes. BPF also appears to protect JH from degradation by enzymes released into the medium. By these mechanisms the insect can maintain elevated JH titers for relatively long periods. Binding protein may also keep JH in solution in the hemolymph allowing its rapid distribution throughout the insect. The data suggest that the binding protein plays a key role in maintaining juvenile hormone titers.

Ionic regulation of the haemolymph in the larvae of the dragonfly Aeshna cyanea (Müller) (Odonata, Anisoptera)

The ionic regulation of the haemolymph of larvae of Aeshna cyanea (Müller) was studied by means of two types of experiments. In the first the change in internal ionic composition was followed as a function of the time spent in a given experimental medium. These experiments led to the conclusion that: 1. the haemolymph composition does not change when larvae are starved in tap water for 10 days; 2. the haemolymph ionic concentrations (Na and Cl) have initial marked increase when the animals are kept in hypertonic media of diluted sea water; after 80 hours however, both concentrations stay constant. In a second series of experiments the internal ionic concentration was compared to a series of different concentrations of external media. From this, the relation between the internal and external ionic concentration was elaborated : in hypotonic media the internal Na and Cl concentrations stay constant, in hypertonic media there is a parallelism between the increase of the external concentration and haemolymph concentration, the internal Na concentration being always slightly hypertonic, the Cl concentration markedly hypotonic. Finally, when larvae are placed in glass distilled water, the internal Na and Cl concentrations begin to decrease after 60 hours.