What determines the number of ovarioles in a fly ovary?

The relation between the size of a fly and the number of ovarioles in its ovary was investigated in Phormia regina and Sarcophaga bullata. Small flies of varying size were produced by taking larvae prematurely off the food. The smallest flies thus obtained were derived from larvae only $\text{1}\text{8}$ of the weight of a normal larva. The number of ovarioles in an ovary is directly proportional to the size of the fly and, in the extreme case, is about $\text{1}\text{5}$ the normal number in Sarcophaga and about $\text{1}\text{3}$ in Phormia. Larvae prematurely taken off the food, but fed again after starving for several days, grow to normal or almost normal size and develop ovaries with about the normal number of ovarioles. Small or re-fed Sarcophaga do not show any changes in the anatomy of individual ovarioles but in Phormia disorders in ovariole development and a consequent reduction of fertility are frequent. The number of ovarioles remains identical from the early pupal stage all through the development of the pharate fly and then through ovarian development in the adult fly: it is determined by the size of the larva when it was taken off the food. This shows that it is not lack of space in a small adult fly abdomen which determines the number nor the occurrence of degenerative processes during ovarian development.     

Mycoplasma pneumoniae: A prokaryote which consumes oxygen and generates superoxide but which lacks superoxide dismutase

Superoxide dismutase and catalase were not detected in $\text{M}$. $\text{pneumoniae}$ and several other species of $\text{Mycoplasma}$ some of which consume oxygen and secrete H₂O₂. $\text{M}$. $\text{pneumoniae}$ in suspension formed O₂^? in the presence of NADH and flavins and extracts of $\text{M}$. $\text{pneumoniae}$ formed O₂^? in the presence of either NADH or NADPH. The lack of superoxide dismutase in $\text{M}$. $\text{pneumoniae}$ could not be attributed to superoxide dismutase in the complex medium in which the organisms were grown because organisms grown in medium in which the superoxide dismutase had been inactivated by heat still contained undetectable amounts. Mycoplasmas appear to be an exception to the rule that organisms which consume O₂ synthesize superoxide dismutase.     

Dietary-induced modification of calcium transport in mitochondria isolated from flight-muscle of developing sheep blowfly Lucilia cuprina

The activity of mitochondrial calcium transport in flight-muscle of the sheep blowfly $\text{Lucilia cuprina}$ is shown to depend on the nature of the diet upon which the adult fly is maintained. The finding raises the possibility that calcium transport in mitochondria from other tissues and species also might be influenced by the dietary intake.     

Evidence for water as the product for oxygen reduction by cytochrome cd.

Evidence is presented that water is the final product of electron donation to molecular oxygen by cytochrome $\text{cd}$ from $\text{Paracoccus}\text{denitrificans}$ when ferrocytochrome $\text{c}$ acts as donor to $\text{cd}$. Negative evidence for the accumulation of superoxide and peroxide was obtained by rate effect experiments in the presence of superoxide dismutase, catalase, and peroxidase. Positive evidence for water was obtained by showing a 4 to 1 stoichiometric balance for rates of electron acceptance from ferrocytochrome $\text{c}$ to rates of donation to molecular oxygen.     

Increase in glutathione peroxidase activity in erythrocytes from trisomy 21 subjects.

Glutathione peroxidase activity has been measured in erythrocytes from normal subjects and from trisomy 21 patients. The latter cases show about 50 % increase of this enzyme similar to the increase observed for superoxide dismutase (erythrocuprein) suggesting either localisation of the gene for glutathione peroxidase on chromosome 21 (as is the case for erythrocuprein) or regulation of this enzyme by intracellular levels of O₂^$\text{?}$, H₂O₂ or superoxide dismutase.     

Evidence for a coordination position available to solute molecules on one of the metals at the active center of reduced bovine superoxide dismutase

We have measured the contribution of the reduced form of bovine $\text{Zn}\text{Cu}$ superoxide dismutase to the relaxation of the ³⁵Cl nucleus of chloride ion. The reduced protein has a molar relaxivity approximately 2.5 greater than the metal free protein, and addition of a small excess of cyanide lowers the relaxivity of the reduced protein to that of the apo-protein. We have interpreted these observations in terms of an open coordination position on one of the two metal ions, and we have proposed a mechanism for the reduction of superoxide by reduced superoxide dismutase which requires that $\text{O}{}_2{}^{\mathrm{?}}$ binds to Cu⁺ prior to electron transfer.     

Physiological aspects of water balance in the Hawaiian drosophilid, Drosophila mimica

The ability to resist desiccation is an important component of biological fitness for terrestrial organisms. Several water balance characteristics have been studied for a strain of laboratory-reared Drosophila mimica and for four populations of D. mimica collected at sites differing in altitude and wetness. In the absence of drinking water, D. mimica are unable to maintain a water balance, even in nearly saturated environments. However, as a_v ($\text{a}{}_{\mathrm{v}}\text{=}\text{r.h.}\text{100}$) decreases, transpiration does not increase as rapidly as expected and absorption remains nearly constant. The size of the fly is not correlated with its water loss characteristics, but some differences in regulation between the sexes are suggested.     

Metabolite concentrations in the liver of the adult and developing guinea pig and the control of glycolysis in vivo.

A range of metabolite concentrations have been determined in the liver of the adult and fetal guinea pig during the latter half of gestation. Adenine nucleotides showed little change during development of the fetal liver and the only major difference from the adult was a low ADP concentration. The hexose phosphates, particularly fructose 1,6-diphosphate, were higher and the triose phosphates in the glycolytic pathway after glyceraldehyde 3-phosphate were lower in the fetal liver. Cytosolic $\text{NAD}{}^{\mathrm{+}}\text{NADH}$ ratios were comparable in both adult and fetal livers as were cytosolic $\text{NADP}{}^{\mathrm{+}}\text{NADPH}$ ratios for the last 15–20 days of gestation. The metabolite concentrations have been used to indicate that glycolysis in the fetal guinea pig liver is controlled largely by hexokinase, glyceraldehyde 3-phosphate dehydrogenase, and pyruvate kinase.     

Progesterone and 20α-hydroxyprogesterone stimulate the in vitro release of GnRH by the isolated mediobasal hypothalamus

An $\text{in}$$\text{vitro}$ perifusion system was used to investigate the effect of progesterone (P₄) and 20α-hydroxyprogesterone (20α-OHP) on the release of GnRH from isolated hypothalamic tissue of the adult ovariectomized estradiol-17β primed rat. Pulse delivery of P₄ stimulated GnRH release not only from the isolated mediobasal hypothalamus-anterior hypothalamus-preoptic area (MBH-AHPOA) complex but also from the MBH alone. Release of GnRH from the MBH was also increased by 20α-OHP. These results suggest that the $\text{in}$$\text{vivo}$ increase of circulating P₄ or 20α-OHP associated with the initiation of the preovulatory LH surge may play a role in regulating the timing or amplitude of this surge by directly stimulating the release of GnRH from the MBH.     

The role of catalytic superoxide formation in the O2 inhibition of nitroreductase.

Many nitroreductases are strongly inhibited by oxygen. The first intermediate of nitroreductase activity, the nitroaromatic anion free radical, cannot be detected in aerobic microsomal incubations. Even though the nitro compounds are unchanged, both nitrofurantoin and $\text{p}$-nitrobenzoate profoundly increase the NADPH-supported oxygen uptake. This catalytic oxygen consumption is partially reversed by superoxide dismutase, suggesting that superoxide anion free radical is being formed by the rapid air oxidation of the nitroaromatic anion radical.     

Letter: Preliminary crystallographic data for spinach superoxide dismutase

Superoxide dismutase from spinach leaves was salted out with ammonium sulphate. The resulting crystals were monoclinic, space group C2, with unit cell dimensions $\text{a = 166.2}\text{A}\text{?}\text{, b = 46.1}\text{A}\text{?}\text{, c = 85.6}\text{A}\text{?}\text{and}\text{β = 99.3 °}$. Considerations of cell volume and protein molecular weight indicated two molecules of superoxide dismutase in the asymmetric unit.     

The Tiron free radical as a sensitive indicator of chloroplastic photoautoxidation

Wheat chloroplasts photochemically reduced molecular oxygen, as a Hill oxidant in the Mehler reaction, to superoxide anion which then oxidized added 1,2-dihydroxybenzene-3,5-disulfonate to its semiquinone, a comparatively stable free radical at pH 7. The last mentioned reaction was rapid in aqueous solution, but the rate of formation of 1,2-dihydroxybenzene-3,5-disulfonate semiquinone by the chloroplast system was calculated as a $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of 0.6 s. The Mehler reaction, or more specifically the univalent reduction of oxygen by Photosystem I, was rate-limiting so that the 1,2-dihydroxybenzene-3,5-disulfonate semiquinone was a useful spin probe for superoxide anion production at room temperature. The ESR signal of 1,2-dihydroxybenzene-3,5-disulfonate semiquinone was proportional to its steady state concentration and decayed in the dark with a $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of 5–6 s. This oxygen-dependent signal was enhanced by mediation of chloroplastic oxygen reduction through methyl viologen. The superoxide anion scavengers ascorbate and l-epinephrine competitively obscured 1,2-dihydroxybenzene-3,5-disulfonate semiquinone formation, but added superoxide dismutase was not as effective in this role. Partial inhibition by superoxide dismutase was achieved only by preincubation of Photosystem I enriched particles with ten times the endogenous concentration of superoxide dismutase. This and the persistence of a small amount of a 1,2-dihydroxybenzene-3,5-disulfonate (Tiron) oxidizing species in the dark supports the concept of Tiron accessibility but not the superoxide dismutase accessibility of superoxide anion bound in its formative enzyme complex. Benzoquinone and naphthoquinone disulfonate also reacted with superoxide anion, and supported both the Hill reaction and the Mehler reaction as final oxidants of both water and superoxide anion.     

Effect of synthetic estrogen on platelet aggregation and vascular release of PGI2-like material in the rabbit

Treatment of adult female New Zealand white rabbits with ethinyl estradiol, the synthetic estrogen used in many oral contraceptives, results in a significant increase in $\text{in vivo}$ aggregation. This alteration in platelet behavior is accompanied by diminished vascular release of antiaggregatory PGI₂ (prostacyclin)-like material. Addition of a progestin prevents the change in platelet aggregation seen with the estrogen alone. Diminished vascular PGI₂ release may be an important factor in the pathogenesis of thrombotic occurrences experienced by some oral contraceptive users. $\text{In vivo}$ platelet aggregation may be of value in identifying individuals at risk of developing thrombotic disturbances while taking oral contraceptives.     

Adult ovaries of Locusta migratoria contain the sequence of biosynthetic intermediates for ecdysone

Ovaries of adult $\text{Locusta migratoria}$ have recently been shown to produce impressive amounts of ecdysone together with low polarity ecdysteroids, some of which cross-react with ecdysone in our RIA. A gas chromatographic-mass spectrometric analysis of extracts from ovaries of $\text{Locusta}$ has shown the presence of following compounds (less polar than ecdysone): 2-deoxy-ecdysone, 2,22-bis-deoxy-ecdysone, 2, 22, 2 5-tri-deoxy-ecdysone, 2, 14, 22, 2 5-tetra-deoxy-ecdysone. No other related ecdysteroids were present in our extracts. Cholesterol is used by $\text{Locusta}$ ovaries as a precursor for ecdysone biosynthesis, as our previous studies with labelled products have shown, and we propose that the compounds detected in the present work represent biosynthetic intermediates between cholesterol and ecdysone in $\text{Locusta}$ ovaries.     

AMP deaminase: Stage-specific isozymes in differentiating chick muscle

The molecular basis of the developmental increase in AMP deaminase activity in chick muscle was investigated with a view toward determining whether isozymes of AMP deaminase exist in embryonic avian muscle and, if so, whether a stage-specific isozyme transition occurs during myogenesis in vivo and in vitro. Under specified conditions, AMP deaminase isozymes in adult chicken brain and muscle may be distinguished on the basis of differences in relative substrate specificities for 5′-dAMP and 5′-AMP (expressed as a ratio of the rates observed with these compounds; i.e., $\text{dAMP}\text{AMP}$ ratios), as well as by differential immunoinactivation by antibody directed against breast muscle AMP deaminase. It was found that the AMP deaminase(s) that is (are) present in 6-day embryos is (are) catalytically and immunologically similar to the enzyme in adult brain. With mixtures of known amounts of adult muscle and brain enzymes, values for the $\text{dAMP}\text{AMP}$ ratio (as well as the fraction of uninactivated AMP deaminase at antibody excess) were proportional to the fraction of muscle isozyme present. Standard curves constructed from these data were used to determine that the fraction of adult muscle-like AMP deaminase in developing muscle, as assessed by $\text{dAMP}\text{AMP}$ ratios (and differential immunoinactivation), on days 6, 8, 10, and 15 were 23 (28), 55 (65), 83 (85), and 93% (96), respectively, Thus, parallel results were obtained for the two techniques, and the isozyme transition is virtually complete by the 15th day of incubation. Primary muscle cultures were used to investigate the isozyme transition of AMP deaminase during myogenesis in vitro. Comparison of the data obtained from primary muscle cultures treated with bromodeoxyuridine, cytosine arabinoside, and fluorodeoxyuridine with data from control cultures showed that biochemical differentiation of AMP deaminase in vitro could be attributed to the muscle cell. Also, the isozyme composition changed from a small percentage of adult muscle-like isozyme at the time of plating, to approximately 100% by the 6th day of culture.     

Characterization of NADPH-cytochrome P-450 reductase from house flies (Musca domestica,L.) susceptible and resistant to insecticides,and the blow fly (Phormia regina,meigen)

NADPH-cytochrome $\text{c}$ reductase was purified by affinity chromatographic techniques from microsomes prepared from the abdomens of insecticide-resistant (R) and -susceptible (S) house flies Musca domestica and of the black blow fly Phormia regina. Data are presented which describe (1) the ability of the purified enzymes to support an in vitro reconstitution of mono-oxygenase activity, (2) the changes in activity of these preparations observed in buffers of varying ionic strength, (3) comparative kinetic behaviour between microsomal and purified forms of the enzymes, (4) the immunochemical characteristics of these preparations, and (5) their amino acid composition. The reductases from the three sources were found to be very similar in all of these tests. Substrate binding constants were 5 μM for NADPH, 12 μM for cytochrome $\text{c}$, and the catalytic mechanism was interpreted as ordered Bi Bi. The inhibitory constant of the reductase from the resistant fly for 2′-AMP, an analogue of NADP⁺, was 187 μM; whereas no assciation of the inhibitor was observed below concentrations of 400 μM for the enzyme of either the susceptible house fly or the blow fly. However, the data are insufficient to suggest that the reductase is a significant factor in insecticide resistance. Compared to the same enzymes from rat and rabbit liver, the insect reductases show a different ionic strength optimum (0.14), have distinct antigenic determinants, and have different levels of acidic and basic amino acids in the membrane-binding peptide.     

Cell recognition and adhesiveness: a possible biological role for the sulfated mucopolysaccharides.

The sulfated mucopolysaccharide composition of different neonate, adult and tumoral tissues is reported. It is shown that each tissue has a characteristic composition with respect to the relative amount, type and molecular size of chondroitin sulfate $\text{A}\text{C}$, chondroitin sulfate B and heparitin sulfate. Neonate and tumor tissues contain large amounts of chondrotin sulfate $\text{A}\text{C}$ which is nearly absent in most adult and normal tissues respectively. Based on these and other results a possible role for the sulfated mucopolysaccharides in cell recognition and adhesiveness is proposed.     

Studies of the genetic and immunologic components of the maternal age effect

To assess the genetic component of the maternal age effect, the frequencies of aneuploid embryos derived from several inbred mouse strains were examined as a function of maternal age. Some of the strains were chosen to evaluate possible etiologic agents: CBA for premature reproductive aging and increased univalent frequency, and $\text{NZB}\text{J}$ and $\text{A}\text{J}$ for predisposition toward autoimmunity. The $\text{C3H}\text{HeJ}$ and $\text{C57BL}\text{6J}$ strains also were examined. Although there was considerable variation between strains, an increased frequency of aneuploid fetuses was observed in all strains as a function of maternal aging. The CBA strain revealed the greatest increase in frequency of aneuploid fetuses at a relatively early maternal age. The effect of autoimmunity was assessed by analyzing the frequency of aneuploid embryos derived from thymectomized $\text{A}\text{J}$ females. No significant difference in aneuploidy was found between thymectomized and control nonthymectomized animals.     

Photobiochemistry in the dark: photohemolysis of red cells sensitized by chlorpromazine-bioenergized triplet acetone system

Chlorpromazine is decomposed when it is treated with bioenergized triplet acetone from the 2-methylpropanal/red cells/O₂ system, forming chlorpromazine-5-oxide, with a concomitant strong hemolytic effect observed by a spectrophotometric method. Experiments with external superoxide dismutase, catalase, benzoate and bicarbonate indicate the absence of $\text{O}{}_2{}^{\mathrm{<mtext>?</mtext>}}$, H₂O₂ and OH· species as the precursor of the hemolytic effect.Comparison between the 2-methylpropanal/peroxidase/O₂ system and the 2-methylpropanal/red cells/O₂ system in the presence of chlorpromazine, indicate that essentially the same type of mechanism occurs in both cases.These results could explain the $\text{in}$$\text{vivo}$ hemolytic and toxic effect of chlorpromazine in the dark.     

Estrogen regulation of superoxide dismutase in normal rat mammary tissues and mammary tumors

Multiple electrophoretic molecular variants of superoxide dismutase were demonstrated in normal rat mammary tissues and DMBA-induced rat mammary tumors. The specific activities of $\text{Cu}\text{Zu}$ superoxide dismutase in mammary tumors of estrogen-treated rats were not significantly different from those activities seen in normal rat mammary tissues. However, the enzyme activities of mammary tumors from untreated rats (no estrogen) were significantly lower than the activities of normal rat mammary tissues. Exogenous estrogen appeared to raise superoxide dismutase levels in DMBA-induced rat mammary tumors to those levels seen in normal rat mammary tissues.