The Effects of Temperature and Body Mass on Jump Performance of the Locust Locusta migratoria

Locusts jump by rapidly releasing energy from cuticular springs built into the hind femur that deform when the femur muscle contracts. This study is the first to examine the effect of temperature on jump energy at each life stage of any orthopteran. Ballistics and high-speed cinematography were used to quantify the energy, distance, and take-off angle of the jump at 15, 25, and 35°C in the locust Locusta migratoria. Allometric analysis across the five juvenile stages at 35°C reveals that jump distance (D; m) scales with body mass (M; g) according to the power equation D = 0.35M ^{0.17±0.08 (95% CI)}, jump take-off angle (A; degrees) scales as A = 52.5M ^0.00±0.06, and jump energy (E; mJ per jump) scales as E = 1.91M ^1.14±0.09. Temperature has no significant effect on the exponent of these relationships, and only a modest effect on the elevation, with an overall Q₁₀ of 1.08 for jump distance and 1.09 for jump energy. On average, adults jump 87% farther and with 74% more energy than predicted based on juvenile scaling data. The positive allometric scaling of jump distance and jump energy across the juvenile life stages is likely facilitated by the concomitant relative increase in the total length (L _f+t; mm) of the femur and tibia of the hind leg, L _f+t = 34.9M ^0.37±0.02. The weak temperature-dependence of jump performance can be traced to the maximum tension of the hind femur muscle and the energy storage capacity of the femur''s cuticular springs. The disproportionately greater jump energy and jump distance of adults is associated with relatively longer (12%) legs and a relatively larger (11%) femur muscle cross-sectional area, which could allow more strain loading into the femur''s cuticular springs. Augmented jump performance in volant adult locusts achieves the take-off velocity required to initiate flight.     

Structural and Functional Impact of SRP54 Mutations Causing Severe Congenital Neutropenia

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G-protein dissociation, GTP-GDP exchange and GTPase activity in control and PMA treated neutrophils stimulated by fMet-Leu-Phe

The addition of the chemotactic factor fMet-Leu-Phe to cell homogenates causes a decrease in the pertussis toxin catalyzed ADP-ribosylation of a 41 kDa protein. The fMet-Leu-Phe induced decrease is not abolished in homogenates prepared from phorbol 12-myristate 13-acetate treated neutrophils. This decreased ribosylation probably reflects a dissociation of the GTP-binding protein oligomer that is not followed by association, possibly because of the release of the alpha-subunit into the suspending medium. Furthermore, fMet-Leu-Phe stimulates the binding of radiolabelled guanylylimidodiphosphate to membrane preparations. Again, the stimulated binding of guanylylimidodiphosphate is not affected by treating the intact neutrophils with phorbol 12-myristate 13-acetate. In addition leukotriene B4, platelet activating factor and fMet-Leu-Phe activate a high-affinity GTPase in membrane preparations. The basal level of this GTPase activity is dramatically inhibited in membrane preparations isolated from cells treated with phorbol 12-myristate 13-acetate. On the other hand, the fMet-Leu-Phe stimulated component is only marginally reduced. The present findings suggest that PMA does not prevent receptor G-protein interaction.     

Plague Meningitis—A Retrospective Analysis of Cases Reported in the United States, 1970-1979

Meningitis caused by Yersinia pestis developed in 6 (6%) of a total of 105 patients with plague reported to the Centers for Disease Control from 1970 to 1979. Five of the six cases occurred in children aged 10 to 15 years. All six patients received antibiotic therapy before meningitis developed, which appeared between the 9th and 14th days after the onset of acute illness in five of the six patients. There were no neurologic sequelae. The antigenic and biochemical profiles of the Y pestis strains isolated from cerebrospinal fluid in the meningitis cases did not differ from those of the Y pestis strains obtained from blood and bubo aspirates in the other 99 patients, and neither did in vitro studies suggest antibiotic resistance. While plague meningitis is an uncommon complication of acute plague infection, physicians in the western United States should be aware that it may develop as much as 14 days after antibiotic therapy for the acute plague infection has been initiated.     

Sulfinyl radical formation from the reaction of cysteine and glutathione thiyl radicals with molecular oxygen

Using Electron Spin Resonance spectroscopy at low temperatures, we find that thiyl radicals resulting from irradiation of frozen aqueous solutions of a variety of thiols, including cysteine, glutathione, and penicillamine react with oxygen to form sulfinyl (RSO.) radicals. The identity of the cysteine sulfinyl radical has been confirmed by the use of molecular oxygen isotopically labeled with 17O. Previous workers have suggested the reaction of thiyl radicals and molecular oxygen resulted in the formation of the potentially damaging thiol peroxyl radical, RSOO.; our work shows no evidence for this species. The sulfinyl radicals are suggested to result from a direct reaction between thiyl radicals and molecular oxygen. This reaction results in the cleavage of the dioxygen bond.     

Effects of tobacco glycoprotein (TGP) on the immune system. III. The effect of aging on the mitogenic response of human peripheral blood lymphocytes to TGP

We have shown that the mitogenic response of human peripheral blood lymphocytes (PBL) to tobacco glycoprotein (TGP), a glycoprotein rich in rutin or rutinlike polyphenol moieties, which is isolated from cured tobacco leaves, does not decrease with age. In contrast, the proliferative response to lipopolysaccharide (LPS) tends to decline with age, and a significant decrease is observed in the mitogenic response to rutin-bovine serum albumin (R-BSA). LPS and R-BSA are similar in some aspects to TGP, the former in that TGP and LPS are both T-independent B-cell mitogens for mice and are both highly negatively charged, and the latter in that covalently bound polyphenol groups are present on both R-BSA and TGP. Although the kinetics of the mitogenic responses to these three mitogens are similar (T. Francus, R. F. Klein, L. Staiano-Coico, G. W. Siskind, and C. G. Becker, Effects of tobacco glycoprotein (TGP) on the immune system. II. TGP is a mitogen for human peripheral blood lymphocytes. Submitted for publication.), multiple regression analyses show no correlation in the mitogenic responses of PBL from young donors to TGP and LPS, to TGP and R-BSA, or to LPS and R-BSA. In contrast, there are significant correlations between the proliferative responses to these mitogens by PBL from old donors. The results suggest that only a small subpopulation of the cells which are stimulated by R-BSA and LPS are not altered with age, and these are most likely the cells that are stimulated by the three mitogens studied.