Storage-excretion of metallic cations in the adult housefly, Musca domestica

The objective of this investigation was to elucidate further the phenomenon of storage-excretion of metallic cations in the housefly. The sites for deposition of zinc, calcium and copper have been identified in this study. The metal intake of the flies was altered by raising one group on sucrose and tap water while in the experimental groups sucrose was supplemented with either 0.05% zinc sulphate, 0.05% calcium phosphate or 0.03% copper sulphate. There were no significant differences in the average life spans of the flies in different groups indicating physiological tolerance to the higher mineral intake. The Malpighian tubules, the midgut and the remainder of the body were analyzed for mineral content in houseflies ranging from 1 to 25 days posteclosion by atomic absorption spectrophotometry. There was a progressive age-associated increase in the total metal content of the flies with age. Zinc and calcium were primarily stored in the Malpighian tubules whereas copper was sequestered in the midgut. Microscopic examination of the epithelial cells of the Malpighian tubules and the midgut revealed a corresponding age-associated increase in mineralized concretions.     

Fine structure and X-ray microanalysis of mineralized concretions in the Malpighian tubules of the housefly, Musca domestica

The epithelium and the lumen of the Malpighian tubules of the housefly contains mineralized dense bodies called concretions. The morphological characteristics, mode of origin, nature of the sequestered elements and the age-associated changes in the distribution of concretions are reported. There are three types of concretions in the cytoplasm, which have been designated as type A, type B, and type C. Type A concretions are membrane-bound spherical structures which may arise by the gradual intravacuolar accumulation of dense material. Type B concretions appear to be related to multivesicular bodies. Type C concretions are heteromorphic and morphologically resemble the residual bodies. They show a positive localization of acid phosphatase reaction product. X-ray microanalysis of intracytoplasmic and intraluminal concretions revealed the presence of phosphorus, sulphur, chlorine, calcium, iron, zinc and copper. There was no evidence suggesting the extrusion of the intracytoplasmic concretions into the lumen of the Malpighian tubules. There is an age-associated increase in the distribution of type C concretions. It is hypothesized that the sequestration of metal ions within the concretions may provide a means for the effective excretion of these elements.     

Hog thyroid peroxidase: physical, chemical, and catalytic properties of the highly purified enzyme.

Studies are reported on the purity and on the physical, chemical, and catalytic properties of a highly purified, stable, thyroid peroxidase (TPO). The enzyme was solubilized by treatment with deoxycholate and trypsin, and it was purified by a series of column treatments, including ion-exchange chromatography on DEAE-cellulose, gel filtration through Bio-Gel P-100, and hydroxylapatite chromatography. The final product, designated TPO VII, had a value for A₄₁₀/A₂₈₀ of 0.54, and its specific activity based on the guaiacol assay (794 μmol of guaiacol oxidized/min/mg) was considerably greater than that of any previously described TPO. Specific activity values based on other peroxidase-catalyzed reactions were also higher for TPO VII than for previous TPO preparations. Purity estimates for TPO VII, based on polyacrylamide disc gel electrophoresis and on isoelectric focusing in polyacrylamide gels, ranged from 80 to 95%. The molecular weight, determined by sedimentation equilibrium, was 93,000. Results of sodium dodecyl sulfate-gel electrophoresis also indicated a molecular weight of approximately 90,000. Sodium dodecyl sulfate-gel electrophoresis under reducing conditions indicated that TPO VII is composed of two peptide chains of unequal size, with the larger about 2.5-fold the size of the smaller. Carbohydrate analysis revealed that TPO is a glycoprotein containing about 10% by weight of carbohydrate. The predominant sugars were mannose and N-acetyl glucosamine. A significant amount of glucose was also found, along with small amounts of galactose, fucose, and xylose. The amino acid composition of TPO VII showed a high proline content, a predominance of arginine over lysine, and a ratio of [Asp] plus [Glu] to [Lys] plus [Arg] of over 2. Isoelectric focusing in polyacrylamide gels indicated an isoelectric pH of 5.75. In agreement with observations made on earlier preparations of TPO, heme spectral data showed significant differences between the pyridine hemochromogens of TPO VII and horseradish peroxidase, suggesting that the heme in TPO is not ferriprotoporphyrin IX. Circular dichroism measurements indicated that approximately 40% of TPO VII involves α helix or β structure.     

Changing behavior of surface immunoglobulin on mouse B lymphocytes during immune development: II. Surface immunoglobulin modulation clearly distinguishes two stages of B-cell maturation in the neonate

Antibody-induced modulation of cell surface IgM was used as a probe to explore membrane-related differences between fetal and adult mouse B lymphocytes. Receptor modulation was studied as a function of temperature in B cells obtained from mice of various ages. Plots of the rate of anti-IgM induced movement of receptors with temperature showed discontinuities (changes in slope) at different characteristic temperatures for each cell. In this way, radical differences between the receptor behavior of fetal B cells and adult B cells were evident. Moreover, temperature-dependent rates of internalization of receptor-ligand complexes also were found to clearly distinguish two stages of B lymphocyte maturation in the mouse.     

Changing behavior of surface immunoglobulin on mouse B lymphocytes during immune development: I. LPS-induced changes in the lateral mobility of B lymphocyte surface immunoglobulins on two populations which express different surface immunoglobulin phenotypes

The redistribution of surface membrane immunoglobulin molecules (sIg) was studied in two functionally distinct populations of mouse splenic B lymphocytes, namely, those bearing membrane IgM(IgG^?) and those bearing IgG. Brief exposure to mitogenic doses of bacterial lipopolysaccharide (LPS) produced direct but differential effects on the subsequent ability of specific antibodies to induce this redistribution on each cell type. Studied as a function of temperature, antibody-induced redistribution of sIgM on cells previously exposed to LPS was observed to occur at temperatures lower than the temperatures required for similar sIgM redistribution on lymphocytes not exposed to LPS. In contrast, mitogen-treated sIgG⁺ cells demonstrated an opposite and long-lasting effect (at least 40 hr), requiring higher temperatures to allow sIgG movement comparable to that seen on untreated sIgG-bearing lymphocytes. Thus, we conclude that LPS interacts with both IgM⁺(IgG^?) and IgG⁺ lymphocytes, but that such interactions produced different membrane effects on each B-cell subset. This membrane change can therefore be useful as a quasi-functional differentiation marker. Furthermore, differences in sensitivity to cellular activation by LPS seen between sIgM-bearing (sIgG^?) and sIgG-bearing B cells may be a reflection of such direct, although different, membrane effects.     

The allomerization of chlorophylls a and b with superoxide anion

The interaction of chlorophylls a and b with electrochemically prepared superoxide anion was studied in aprotic solvent. It was found that O₂^?·causes the deprotonation at carbon C-10 of ring V and production of chlorophyll enolate ions. The intermediate anions undergo rapid oxidation into corresponding chlorins. Pyrochlorophyll a, which lacks the C-10 carboxymethyl group, did not show the transformation. It is suggested that more strong free radical oxidants (e.g., HO₂·, or RO₂·) are capable of abstracting the hydrogen atom at C-10. The possible significance of free radical deprotonation and oxidation in chlorophyll allomerization is discussed.     

Villin is a major protein of the microvillus cystoskeleton which binds both G and F actin in a calcium-dependent manner

The cores of the microvilli present on intestinal epithelial cells are currently the only microfilament arrangement which can be isolated ultrastructurally intact and in sufficient quantities for biochemical analysis. We have isolated and characterized villin, a major protein of the microvillus core. Using villin's ability to bind very tightly to immobilized monomeric actin in a calcium-dependent manner, we have developed a method for its rapid purification by affinity chromatography on G actin, which itself was bound to immobilized pancreatic deoxyribonuclease I (DNAase I). The villin-G actin complex on DNAase I is resistant to high ionic strength, and villin, but not actin, is released when the calcium concentration is less than 10⁶ M. Purified villin behaves as a globular monomeric protein of molecular weight 95,000, and is free of carbohydrate. Villin also interacts with F actin. In the absence of calcium, villin cross-links F actin having the properties of an F actin bundling or gelation factor. In the presence of calcium (>10^?7 M), villin apparently restricts the polymerization of actin to short filaments which cannot be readily sedimented. The properties of villin are not compatible with its previously suggested role as the cross-filament between the microvillus microfilament core and the plasma membrane, but rather indicate a function as a calcium-dependent F actin-bundling protein. The role of villin is discussed in terms of the other protein components of the microvillus core and in relation to recently described calcium-dependent gelation factors.     

Endocrine events during pre-diapause and non-diapause larval-pupal development of the tobacco hornworm, Manduca sexta

The haemolymph ecdysteroid titre and in vitro capacities of prothoracic glands and corpora allata to synthesize ecdysone and juvenile hormone, respectively, during the last-larval instar of diapause-destined (short-day) and non-diapause-destined (long-day) Manduca sexta were investigated. In general, the ecdysteroid titres for both populations of larvae were the same and exhibited the two peaks characteristic of the haemolymph titre during this developmental stage in Manduca. The only difference in the titre occurred between day 7 plus 12 h and day 7 plus 20 h, when the short-day larval titre did not decrease as quickly as the long-day titre. The in vitro synthesis of ecdysone by prothoracic glands of short- and long-day larvae during the pharate pupal phase of the instar were also essentially the same. Activity fluctuated at times which would support the idea that ecdysone synthesis by the glands is a major contributing factor to the changes in the haemolymph ecdysteroid titre. There was one subtle difference in prothoracic gland activity between the two populations, occurring on day 7 plus 2 h. By day 7 plus 10 h, however, rates of ecdysone synthesis by the short- and long-day glands were comparable. This elevated activity of the short-day glands occurred just prior to the period the haemolymph ecdysteroid titre remained elevated in these larvae. The capacities of corpora allata to synthesize juvenile hormone I and III in vitro were not markedly different in long- and short-day last-instar larvae. At the time of prothoracicotropic hormone release in the early pupa, activity of corpora allata from short- and long-day reared animals was low and also essentially the same. There were a few differences in the levels of synthesis at isolated times, but they were not consistent for both homologues. Overall, there are no compelling differences in the fluctuations of ecdysteroids and juvenile hormones between diapause-destined and non-diapause-destined Manduca larvae. Since these hormones do not appear to play any obviously significant role in the induction of pupal diapause in this insect, the photoperiodic induction of diapause in Manduca appears to be a predominantly brain-centred phenomenon not involving endocrine effectors.     

Phospholipid composition of lamellar bodies formed by fetal rabbit lung type II cells in organ culture

Lung tissue obtained from fetal rabbits of 23 days gestational age was maintained in organ culture to study the in vitro formation of lamellar body phospholipids. During the culture period, the epithelium of the prealveolar ducts of the explants differentiated to form type II pneumonocytes. After 8 days in culture, the explants were harvested, homogenized, and two lamellar body fractions were isolated by sucrose density gradient centrifugation. The lamellar body fraction which best retained the distinct multilamellar structure was recovered at the interface between a solution of buffer without sucrose and buffer containing 0.41 m sucrose. The phospholipid compositions of both lamellar body fractions were similar to those reported for lamellar bodies and surfactant isolated from fetal rabbit lung, with the exception of a slightly higher phosphatidylethanolamine content. The disaturated phosphatidylcholine content of the lamellar body fractions, expressed as a percentage of total lipid phosphorus, was not influenced by the presence of palmitate in the medium.     

Delayed fluorescence from Chlorella: I. Low temperature observations

Delayed fluorescence has been observed from Chlorella whole cells at 0.5 ms following flash excitation and at temperatures from 293 °K to 120 °K. Cells which are cooled while pre-illuminated before flashes produce less observed delayed fluorescence than cells cooled without pre-illumination. There exists a small component of delayed fluorescence whose magnitude is independent of pre-illumination effects. The effect of pre-illumination upon delayed fluorescence emission is eliminated by prior freezing of the algae.     

An analysis of sandbathing and grooming in the kangaroo rat (Dipodomys merriami)

The sandbathing and grooming behaviour of ten kangaroo rats (Dipodomys merriami) were recorded on sand and woodchip substrates after periods of 0,1,5 and 10 days without sand. Sandbathing is restricted to the sandy substrate. Grooming occurs on both, but with a higher frequency on sand. Increases in both grooming and sandbathing occur with increasing sand deprivation, but the temporal patterning does not change. D. merriami tends to alternate sandbathing components in contrast to other Dipodomys species. Lipid on the pelage increases noticeably with sand deprivation and decreases during a sandbathing bout; sand appears to be removed from the pelage by shaking and grooming. These findings suggest a three-process system for care of the body surface.     

Increased queen-like behaviour of workers in large colonies of the sweat bee Lasioglossum zephyrum

Observations were made on Lasioglossum zephyrum colonies containing from one to 17 workers. In experiment I, the most dominant workers in larger colonies exhibited more queen-like characteristics in their interactions with nestmates than did those in smaller colonies. In experiment II, a higher proportion of workers in large than in small colonies were willing to mate with males. These results are consistent with the hypothesis that the queen's ability to suppress queen-like behaviour in workers declines with increasing colony size.     

Macrocyclic polyphosphane ligands: cobalt(II) and nickel(II) complexes of 1,10-dipropyl-4RS, 7SR, 13SR, 16RS-tetraphenyl-1,10-diaza-4,7,13,16-tetraphospha-cyclooctadecane and crystal structure of the cobalt tetraphenylborate monohydrate complex

The X-ray crystal structure of the title compound has been carried out. The crystals are triclinic, space group P$\text{1}$, a = 13.252(2), b = 13.943(2), c = 24.316(5) Å, α = 70.660(14), β = 75.219(14), γ = 69.231(13)° for Z = 2. The structure has been refined to an R factor of 0.069 by the least-squares technique. The cobalt atom is five-coordinated by the four phosphorus atoms of the macrocycle and by a water molecule forming a distorted square-pyramidal geometry. The stereochemistry of some cobalt(II) and nickel(II) complexes of the same ligand were investigated, in the solid state and in solution, by electronic spectroscopy.     

Evaluation of the water environments in deoxygenated sickle cells by longitudinal and transverse water proton relaxation rates

The longitudinal and transverse water proton relaxation rates of oxygenated and deoxygenated erythrocytes from both normal adults and individuals with sickle cell disease were measured as a function of temperature at two different frequencies. The simplest model which fits all of the data consists of three different environments for water molecules. The majority of the water (98%) has a correlation time indistinguishable from bulk water (3 × 10^?11 sec). Secondly, there is a small amount of water (1.3–1.5%) present which has a correlation time of 2–4 × 10 ^?9 sec and is apparently independent of the erythrocyte sample studied. Presumably this water is the hydration sphere around the hemoglobin molecules and its correlation time is significantly slower than bulk water. The third environment contains approximately 0.2% of the water present and has a correlation time≥ 10^?7 sec. This third environment is considered tightly bound to the hemoglobin because the water proton correlation time is very similar to the expected rotational correlation time for the hemoglobin molecules. The value of the transverse relaxation rate, f_b(T_2b)^?1, for the tightly bound water fraction decreases in oxy ($\text{S}\text{S}$), deoxy ($\text{A}\text{A}$), and oxy ($\text{A}\text{A}$) erythrocyte samples as the temperature is increased as expected for a rotational correlation time process. In dramatic contrast,f_b (T_2b)^?1 increases almost linearly as the temperature is increased over the whole 4 ° to 37 °C temperature range in samples of deoxy ($\text{S}\text{S}$) erythrocytes. The observation suggests a continual increase in the formation of deoxyhemoglobulin S polymers rather than a sudden transition from a homogeneous solution of deoxyhemoglobin S molecules to a solid gel.     

Eosinophil-mediated killing of schistosomula of Schistosoma mansoni: Oxidative requirement for enhancement by eosinophil colony stimulating factor (CSF-α) and supernatants with eosinophil cytotoxicity enhancing activity (E-CEA)

Factors which enhance eosinophil-mediated killing of antibody-coated schistosomula of Schistosoma mansoni include semipurified eosinophil colony stimulating factor (CSF-α) and eosinophil cytotoxicity enhancing activity (E-CEA) present in supernatants from cultured mononuclear cells. We have examined the mechanism of enhancement. Both actions require oxygen in order to enhance killing and do not enhance killing under anaerobic conditions (P ? 0.005). E-CEA had no detectable effect upon oxidative metabolism. In contrast to CSF-α which, in our previous studies, increased Superoxide anion productions and quantitative leukocyte iodination, E-CEA had no detectable effect upon oxidative metabolism. In order to test whether active oxygen products might mediate enhancement of killing, the effects of the addition of Superoxide dismutase and catalase were tested. Neither enzyme showed inhibition of CSF-α or E-CEA enhancement of eosinophil-mediated killing. The effects of CSF-α and E-CEA were not additive. These studies suggest that both CSF-α and E-CEA exert enhancement of killing by means of an as yet unidentified oxygen requiring process.     

Methylated amino acids and lysosomal function in cultured heart cells

Methylated amino acids inhibit lysosomal function in cultured rat heart myocytes more effectively than the classically employed lysosomotropic weak bases. Moreover, L-leucine methyl ester (L-Leu-OMe) or L-methionine methyl ester (L-Meth-OMe) do not alter lysosomal pH or inactivate lysosomal cysteine proteinases, but do inhibit protein degradation more efficiently than either chloroquine or NH4Cl. These observations suggest that amino acid methyl esters are more effective probes to investigate lysosomal function in cultured myocytes than chloroquine or NH4Cl.     

The relationship of age,sex, and reproductive state to assimilation efficiency in the adult milkweed bug, Oncopeltus fasciatus

The influence of age, sex, and reproductive state on efficiency of assimilation was examined in the milkweed bug Oncopeltus fasciatus. Amounts of food ingested and excreted decline with age in virgin males and females. Mated females laying eggs ingest significantly more food than virgin animals of either sex and also maintain a consistently higher assimilation efficiency. A qualitative analysis of the level of assimilation required for reproductive effort is discussed.     

Intersex,a temperature-sensitive mutant of the nematode Caenorhabditis elegans

A temperature-sensitive mutation, isx-1(hc17), is reported in the nematode Caenorhabditis elegans which alters the sexual phenotypes of both genotypic sexes. At the restrictive temperature, XX animals are functionally female rather than hermaphroditic due to the absence of spermatogenesis, and XO animals develop as intersexes. These intersexes have normal male head and tail structures and exhibit some mating behavior, but possess hermaphrodite-like gonads which produce no sperm and usually contain a few oocytes. An abortive vulva is usually present and evidence is presented which suggests that the formation of the vulva by the hypodermis is induced by the underlying gonad. The direct effects of the mutation are confined to the descendants of four primordial gonad cells. Gametogenesis and gonad sheath development do not seem to be tightly coupled and are shown to differ in their responses to X-chromosome dosage. The interaction of the intersex mutation with mutant alleles of two transformer genes tra-1 and tra-2 is discussed and a model for the action of these genes in gonad development and sex determination is proposed.