Results of crossing Euschistus variolarius and Euschistus servus with Reference to the Inheritance of an exclusively Male Character

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Results of crossing Euschistus variolarius and Euschistus servus with Reference to the Inheritance of an exclusively Male Character

     

Cardiovascular actions of prostaglandins F2α; 15-me-F2α; F1α; F2β and F1β in the cat

Prostaglandin F_2α (5μg/kg, i.v.) causes an increase in pulmonary arterial pressure, decrease in systemic arterial pressure, and reflex bradycardia in the anesthetized cat. The same dose of the 15-methyl analogue of PGF_2α produces the same triad of effects but of greater magnitude and duration. Although prostaglandins F_1α, F_2β and F_1β also cause the same cardiovascular effects as F_2α, there is a decrease in potency for all parameters measured, with PGF_2α>PGF_1α>PGF_2β>PGF_1β. When compared to the actions of PGF_2α in producing an increase in pulmonary arterial pressure, PGs F_1α, F_2β and F_1β were less potent by approximately 10, 100, and 1000 fold respectively.     

Synthesis and biological activities of leukotriene F4 and leukotriene F4 sulfone

Leukotriene F₄ (LTF₄ and LTF₄ sulfone have been synthesized and their biological activities determined in the guinea pig. LFT₄ displayed comparable activity to LTD₄ on guinea pig trachea and parenchyma but was less active on the ileum. When injected intravenously into the guinea pig, LTF₄ induced a bronchoconstriction (ED₅₀ 16 μg Kg⁻¹) which was blocked by indomethacin and FPL-55712 and was 50–100 X less potent than LTD₄ in this assay. LTF₄ sulfone was approximately 2–5 times less active than LTF₄ and . When injected into guinea pig skin with PGE₂ (100 ng); LTF₄ and LTF₄ sulfone (10–1000 ng) induced changes in vascular permeability. The order of potency in this assay was LTE₄ sulfone = LTD₄ = LTD₄ sulfone > LTE₄ > LTF₄ = LTF₄ sulfone.     

Paraplacental passage of 3H-prostaglandin F2

Prostaglandins F_2α permeates the live and denaturated whole fetal membranes as well as their isolated components chorion and amnion. The permeability constant in our vitro method is 1.3 × 10^?3 cm/min for PG. If 40 mg PG are instilled intra-amniotically at term — as used in therapeutical abortion — then 3.7 mg prostaglandin F_2α would pass per hour from the amniotic fluid through the fetal membranes into the decidua.     

Suppression of ρ 0 lethality by mitochondrial ATP synthase F1 mutations in Kluyveromyces lactis occurs in the absence of F0

Specific mgi mutations in the α, β or γ subunits of the mitochondrial F₁-ATPase have previously been found to suppress ρ⁰ lethality in the petite-negative yeast Kluyveromyces lactis. To determine whether the suppressive activity of the altered F₁ is dependent on the F₀ sector of ATP synthase, we isolated and disrupted the genes KlATP4, 5 and 7, the three nuclear genes encoding subunits b, OSCP and d. Strains disrupted for any one, or all three of these genes are respiration deficient and have reduced viability. However a strain devoid of the three nuclear genes is still unable to lose mitochondrial DNA, whereas a mgi mutant with the three genes inactivated remains petite-positive. In the latter case, ρ⁰ mutants can be isolated, upon treatment with ethidium bromide, that lack six major F₀ subunits, namely the nucleus-encoded subunits b, OSCP and d, and the mitochondrially encoded Atp6, 8 and 9p. Production of ρ⁰ mutants indicates that an F₁-complex carrying a mgi mutation can assemble in the absence of F₀ subunits and that suppression of ρ⁰ lethality is an intrinsic property of the altered F₁ particle. Received: 7 April 1998 / Accepted: 10 June 1998     

Subunit a of the F1F0 ATP Synthase Requires YidC and SecYEG for Membrane Insertion

The insertion of inner membrane proteins in Escherichia coli occurs almost exclusively via the SecYEG pathway, while some membrane proteins require the membrane protein insertase YidC. In vitro analysis demonstrates that subunit a of the F₁F₀ ATP synthase (F₀a) is strictly dependent on Ffh, SecYEG and YidC for its membrane insertion but independent of the proton motive force. The insertion of the first transmembrane segment of F₀a also depends on Ffh and SecYEG but not on YidC, whereas the insertion is strongly dependent on the proton motive force, unlike the full-length F₀a protein. These data demonstrate an extensive role of YidC in the assembly of the F₀ sector of the F₁F₀ ATP synthase.     

A unique mechanism of curcumin inhibition on F1 ATPase

ATP synthase (F-ATPase) function depends upon catalytic and rotation cycles of the F₁ sector. Previously, we found that F₁ ATPase activity is inhibited by the dietary polyphenols, curcumin, quercetin, and piceatannol, but that the inhibitory kinetics of curcumin differs from that of the other two polyphenols (Sekiya et al., 2012, 2014). In the present study, we analyzed Escherichia coli F₁ ATPase rotational catalysis to identify differences in the inhibitory mechanism of curcumin versus quercetin and piceatannol. These compounds did not affect the 120° rotation step for ATP binding and ADP release, though they significantly increased the catalytic dwell duration for ATP hydrolysis. Analysis of wild-type F₁ and a mutant lacking part of the piceatannol binding site (γΔ277–286) indicates that curcumin binds to F₁ differently from piceatannol and quercetin. The unique inhibitory mechanism of curcumin is also suggested from its effect on F₁ mutants with defective β–γ subunit interactions (γMet23 to Lys) or β conformational changes (βSer174 to Phe). These results confirm that smooth interaction between each β subunit and entire γ subunit in F₁ is pertinent for rotational catalysis.     

Cardiolipin is essential for higher proton translocation activity of reconstituted F0

The F₀ membrane domain of F₀F₁-ATPase complex had been purified from porcine heart mitochondria. SDS-PAGE with silver staining indicated that the purity of F₀ was about 85% and the sample contained no subunits of F₁-ATPase. The purified F₀ was reconstituted into liposomes with different phospholipid composition, and the effect of CL (cardiolipin), PA (phosphatidic acid), PI (phosphatidylinositol) and PS (phosphatidylserine) on the H⁺ translocation activity of F₀ was investigated. The results demonstrated that CL, PA and PI could promote the proton translocation of F₀ with the order of CLPA>PI, while PS inhibited it. Meanwhile ADM (adriamycin) severely impaired the proton translocation activity of F₀ vesicles containing CL, which suggested that CL’s stimulation of the activity of reconstituted F₀ might correlate with its non-bilayer propensity. After F₀ was incorporated into the liposomes containing PE (phosphatidylethanolamine), DOPE (dioleoylphosphatidylethanolamine) as well as DEPE (dielaidoylphosphatidylethanolamine), it was found that the proton translocation activity of F₀ vesicles increased with the increasing content of PE or DOPE, which has high propensity of forming non-bilayer structure, but was independent of DEPE. The dynamic quenching of the intrinsic fluorescence of tryptophan by HB (hypocrellin B) as well as fluorescent spectrum of acrylodan labeling F₀ at cysteine indicated that CL could induce F₀ to a suitable conformation resulting in higher proton translocation activity.     

Construction of secalotriticum (Rye-wheat amphidiploids with the rye cytoplasm (RRAABB, 2n = 42)), the formation of the karyotypes of the F1BC1 and F1BC2 rye-triticale amphidiploids, and commercial and biological characteristics of the early secalotriticum generations

The karyotype formation was studied in the F₁BC₁ and F₁BC₂ hybrids of Secale cereale L. ssp. tetraplodium Kobyl. (RRRR, 4x = 28) and Triticale (AABBRR, 6x = 42). The hybrid karyotypes were heterogenomic for homeologous chromosome groups of the wheat and rye genomes. The hybrids differed in cytological stability, the balance of chromosomes of the original species, and the fertility of spikes. The majority of F₁BC₁ and F₁BC₂ plants were cytologically unstable and unbalanced in chromosome composition and displayed a low spike fertility. Cytologically stable hexaploids occurred in F₁BC₁ and F₁BC₂ at a frequency of 1.0 and 9.5%, respectively. The resulting hexaploid secalotriticum lines (RRAABB, 6x = 42) were genotypically diverse and morphogenetically various. The genetic factors responsible for the diversity of the F₁BC₁ and F₁BC₂ rye-triticale amphiploids and early secalotriticum generations are discussed. Original Russian Text ? N.B. Belko, I.A. Gordei, I.S. Shchetko, 2009, published in Genetika, 2009, Vol. 45, No. 5, pp. 642–651.     

Effect of prostaglandins E1, E2 and F2α on neutrophil aggregation

Recently we have found that chemotactic factors stimulate neutrophils in suspension to aggregate. Because of an obvious analogy to platelet aggregation, we examined the influence of three prostaglandins on this process. Prostaglandins E₁, E₂ and F_2α alone did not cause aggregation of the neutrophils but were able to partially inhibit the aggregation response induced by the synthetic chemotactic tripeptide, formly-methionyl-leucyl-phenylalanine. The minimal inhibitory concentrations for prostaglandins E₁, E₂ and F_2α were 10⁻⁷, 10⁻⁶ and 10⁻⁵M, respectively. These results are similar to those found for the prostaglandin-induced inhibition of platelet aggregation. It may be, therefore, that neutrophil aggregation, like platelet aggregation, is modulated by intracellular prostaglandins and other products of arachidonic acid metabolism.     

Cation requirement for the reconstitution of oligomycin-sensitive ATPase by means of soluble F1-ATPase and F1-depleted submitochondrial particles

Bovine heart submitochondrial particles depleted of F₁ by treatment with urea (‘F₁-depleted particles’) were incubated with soluble F₁-ATPase. The binding of F₁ to the particles and the concomitant conferral of oligomycin sensitivity on the ATPase activity required the presence of cations in the incubation medium. NH⁺₄, K⁺, Rb⁺, Cs⁺, Na⁺ and Li⁺ promoted reconstitution maximally at 40–74 mM, guanidinium⁺ and Tris⁺ at 20–30 mM, and Ca²⁺ and Mg²⁺ at 3–5 mM. The particles exhibited a negative ζ-potential, as determined by microelectrophoresis, and this was neutralized by mono- and divalent cations in the same concentration range as that needed to promote F₁ binding and reconstitution of oligomycin-sensitive ATPase. It is concluded that the cations act by neutralizing negative charges on the membrane surface, mainly negatively charged phospholipids. These results are discussed in relation to earlier findings reported in the literature with F₁-depleted thylakoid membranes and with submitochondrial particles depleted of both F₁ and the coupling proteins F₆ and oligomycin sensitivity-conferring protein.     

Effects of prostaglandins Fα on dog thyroid cyclic AMP level and function

Prostaglandins F_1α and F_2α, at high concentrations (≥28 μM) enhanced cyclic AMP accumulation in dog thyroid slices. At lower concentrations, they inhibited the cyclic AMP accumulation induced by thyrotropin (TSH), prostaglandin E₁, and cholera toxin. This effect was rapid in onset and of short duration, calcium-dependent and suppressed by methylxanthines. Prostaglandin F_α also inhibited TSH-induced secretion and activated iodine binding to proteins. These characteristics are similar to those of carbamylcholine action, except that prostaglandins F did not enhance cyclic GMP accumulation. The effect of prostaglandin F_α was not inhibited by atropine, phentolamine and adenosine deaminase and can therefore not be ascribed to an induced secretion of acetylcholine, norepinephrine or adenosine. It is suggested that prostaglandins F act by increasing influx of extracellular Ca²⁺. Arachidonic acid also inhibited the TSH-induced cyclic AMP accumulation. However this effect was specific for TSH, it was enhanced in the absence of calcium and was not inhibited by methylxanthines or by indomethacin at concentrations which completely block its conversion to prostaglandin F_α. Arachidonic acid action is sustained. This suggests that arachidonic acid inhibits thyroid adenylate cyclase at the level of its TSH receptor and that this effect is not mediated by prostaglandin F_α or any other cyclooxygenase product.     

The interaction between the mitochondrial ATPase (F1) and the ATPase inhibitor

1. The naturally occurring mitochondrial ATPase inhibitor inhibits the mitochondrial ATPase (F₁) non-competitively.2. The interaction between inhibitor and inhibitor-depleted F₁ or submitochondrial particles is diminished when the ratio of ATP/ADP is low or when energy is generated by substrate oxidation.3. The dissociation of the inhibitor from coupled Mg-ATP particles is promoted when substrates are being oxidized. This results in the appearance of a large uncoupler-stimulated ATPase activity. Activation of the uncoupler-stimulated ATPase activity is also achieved by incubation of the particles with ADP.4. The ATPase activity of Mg-ATP particles is determined by the turnover capacity of F₁. When endogenous inhibitor is removed, energy dissipation becomes the rate-limiting step. This energy dissipation can be activated by an uncoupler.5. Evidence is presented for the existence of a non-inhibited intermediate F₁-inhibitor complex.     

Molecular Dynamics Simulations of the Rotary Motor F0 under External Electric Fields across the Membrane

The membrane-bound component F₀, which is a major component of the F₀F₁-ATP synthase, works as a rotary motor and plays a central role in driving the F₁ component to transform chemiosmotic energy into ATP synthesis. We conducted molecular dynamics simulations of b₂-free F₀ in a 1-palmitoyl-2-oleoyl-phosphatidylcholine lipid bilayer for tens of nanoseconds with two different protonation states of the cAsp-61 residue at the interface of the a-c complex in the absence of electric fields and under electric fields of ±0.03 V/nm across the membrane. To our surprise, we observed that the upper half of the N-terminal helix of the c₁ subunit rotated about its axis clockwise by 30°. An energetic analysis revealed that the electrostatic repulsion between this N-terminal helix and subunit c₁₂ was a major contributor to the observed rotation. A correlation map analysis indicated that the correlated motions of residues in the interface of the a-c complex were significantly reduced by external electric fields. The deuterium order parameter (S_CD) profile calculated by averaging all the lipids in the F₀-bound bilayer was not very different from that of the pure bilayer system, in agreement with recent ²H solid-state NMR experiments. However, by delineating the lipid properties according to their vicinity to F₀, we found that the S_CD profiles of different lipid shells were prominently different. Lipids close to F₀ formed a more ordered structure. Similarly, the lateral diffusion of lipids on the membrane surface also followed a shell-dependent behavior. The lipids in the proximity of F₀ exhibited very significantly reduced diffusional motion. The numerical value of S_CD was anticorrelated with that of the diffusion coefficient, i.e., the more ordered lipid structures led to slower lipid diffusion. Our findings will help elucidate the dynamics of F₀ depending on the protonation state and electric field, and may also shed some light on the interactions between the motor F₀ and its surrounding lipids under physiological conditions, which could help to rationalize its extraordinary energy conversion efficiency.     

The use of aurovertin to determine the F1 content of submitochondrial particles and the ATPase complex

(1) The concentration of aurovertin-binding sites calculated from fluorimetric titrations of submitochondrial particles is equal to the F₁ concentration, calculated from the concentration of F₁-binding sites in stripped particles.(2) Direct binding experiments show that the fluorescence enhancement of aurovertin bound to submitochondrial particles and the isolated ATPase complex is less (or absent) at higher concentrations than at lower concentrations. The binding data can be described by ‘specific’ and ‘non-specific’ binding. The concentration of the ‘specific’ sites is twice that derived from fluorimetric titrations.(3) After dissociation of the bound F₁ with LiCl, fluorimetric titrations with aurovertin yield linear Scatchard plots. The fluorescence enhancement and K_D are equal to those of the β-subunit-aurovertin complex. The concentration of β-subunits is double the concentration of F₁.(4) It is concluded that both for submitochondrial particles and the isolated ATPase complex the most reliable and simple way to determine the F₁ content is to dissociate the F₁ with LiCl, spin down the insoluble material and titrate the supernatant (containing free β-subunit) with aurovertin.     

Interaction of beef-heart mitochondrial ATPase,coupling factor F1, with aurovertin

The antibiotic aurovertin binds to beef-heart mitochondrial ATPase, coupling Factor F₁, with biphasic fluorescence enhancement. Specific binding effects, polarity and viscosity changes may all contribute to the enhancement. Evidence is presented that it stems from aurovertin binding followed by a slow conformational change in F₁. This occurs more rapidly in dissociated F₁. The effect of substrates of the enzyme on the fluorescence enhancement is examined. Evidence is presented that in the absence of added magnesium, F₁ can hydrolyse low concentrations of added ATP.     

Precocene-induced sterility in F1 generation of Glossina morsitans morsitans

Precocene treatment does not disrupt the events of reproduction in Glossina morsitans morsitans or induce any apparent changes in treated tsetse. However, some females of the F₁ generation are either sterile or show retardations in follicle development. Sterility is not reversed spontaneously or with juvenile hormone analogues. The critical period for precocene action is related to each ovulation. The corpora allata of precocene-treated tsetse are normal, but those of F₁ sterile females are degenerate. The occurrence of retardation has enabled the characterisation of stages in follicle development in G. m. morsitans.     

Analysis of prostaglandins by electron-capture gas chromatography. I. Thermal decomposition of heptafluorobutyrate methyl esters of F1α and F2α

Triheptafluorobutyrate methyl ester (THFB-Met) derivatives are easily prepared from prostaglandins F_1α and F_2α by successive methylation and heptafluorobutyrylation. The derivatives are reasonably stable during storage, are volatile, and can be detected in the picogram range by electron-capture gas chromatography. Both derivatives exhibit peak broadening or multiple peak formation during gas chromatography at 190°–210°C. Decomposition is independent of the nature of the stationary phase and can be increased by prior heating. Studies with other derivatives suggest that thermal decomposition of the THFB-Met derivatives occuring during gas chromatography involves loss of a heptafluorobutyrate group from the allylic position 15 of the prostaglandins.     

Differential effects of detergents and dimethylsulfoxide on membrane prostaglandin E1 and F2α receptors

Pretreatment of membranes for 1 hr at 4° with up to 0.1% Triton X-100 (TX-100) and sodium desoxycholate (SDC), resulted in a greater loss of [³H] prostaglandin (PG)F₂α binding compared to E₁ binding. Lubrol WX (LWX) tended to cause a greater loss of [³H]PGF₂α than E₁ binding. However, the differential loss was not as marked as with TX-100 or SDC. Triton X-305 was relatively ineffective, but loss of [³H]PGE₁ binding was greater than for PGF₂α. Increasing concentrations of dimethylsulfoxide (DMSO) progressively inhibited PGF₂α binding without affecting PGE₁ binding. The detergent, but not DMSO, induced losses of membrane PG binding were due to solubilization of the receptors. Greater amounts of membrane protein and phospholipids were solubilized at detergent (TX-100 and SDC) concentrations that solubilized 100% of PGE₁ receptors compared to 100% solubilization of F₂α receptors. Neither the duration of preincubation nor the amount of membrane protein chosen were responsible for differential PGE₁ and F₂α receptor losses. These differential membrane PG receptor losses raise the possibility of differences in PGE₁ and F₂α receptors association with the membrane structure.     

Effects of indomethacin, prostaglandin E2, prostaglandin F2α and 6-keto-prostaglandin F1α on hatching of mouse blastocysts

The present study has been performed to investigate how PGs would participate the hatching process. Effects of indomethacin, an antagonist to PGs biosynthesis, on the hatching of mouse blastocysts were examined in vitro. Furthermore, it was studied that prostaglandin E₂ (PGE₂), prostaglandin F_2α (PGF_2α) or 6-keto-prostaglandin F_1α (6-keto-PGF_1α) were added to the culture media with indomethacin. (1) The hatching was inhibited by indomethacin yet the inhibition was reversible. (2) In the groups with indomethacin and PGE₂, no improvement was seen in the inhibition of hatching and the inhibition was irreversible. (3) In the groups with indomethacin and PGF_2α, inhibition of hatching was improved in comparison with the group with indomethacin. (4) In the groups with indomethacin and 6-keto-PGF_1α, no improvement was seen. The above results indicated that PGF_2α possibly had an accelerating effect on hatching and a high concentration of PGE₂ would exert cytotoxic effect on blastocysts.