Observation of Rainbows in the Rotationally Inelastic Scattering of NO with CH4.

Using a combination of velocity-map imaging and resonance-enhanced multiphoton ionization detection with crossed molecular beam scattering, the dynamics of rotational energy transfer have been examined for NO in collisions with CH4 at a mean collision energy of 700 cm-1. The images of NO scattered into individual rotational (jNO') and spin-orbit (Ω) levels typically exhibit a single broad maximum that gradually shifts from the forward to the backward scattering direction with increasing rotational excitation (i.e., larger ΔjNO). The rotational rainbow angles calculated with a two-dimensional hard ellipse model show reasonable agreement with the observed angles corresponding to the maxima in the differential cross sections extracted from the images for higher ΔjNO transitions, but there are clear discrepancies for lower ΔjNO (in particular, final rotational levels with jNO' = 7.5 and 8.5). The sharply forward scattered angular distributions for these lower ΔjNO transitions better agree with the predictions of an L-type rainbow model. The more highly rotationally excited NO appears to coincide with low rotational excitation of the co-product CH4, indicating a degree of rotational product-pair anticorrelation in this bimolecular scattering.

Collision Energy Dependence of the Competing Mechanisms of Reaction of Chlorine Atoms with Propene.

Quasi-classical trajectory simulations examine the reaction of Cl with propene across a range of collision energies, from 7 to 28 kJ mol-1. The majority (70% at 7 kJ mol-1, 86% at 14 kJ mol-1, and 93% at 28 kJ mol-1) of reactive trajectories produce HCl by direct abstraction of a hydrogen atom from the methyl group of propene, but the remainder involve a variety of delayed mechanisms. Among these longer-lived trajectories, transient formation of an energized 1-chloropropyl radical intermediate is predominant, with only a minor contribution from the 2-chloropropyl radical and roaming pathways. The branching ratios between these intermediate states are largely invariant to collision energy, although the overall proportion of indirect trajectories increases at lower collision energies. The greater role for longer-lived trajectories is reflected in the computed product scattering angle distributions, which become more isotropic at lower energies. However, the distributions of population over vibrational and rotational states of the product HCl do not change with collision energy because they are controlled by the dynamics late along the reaction path.

Nematode Population Fluctuations during Decomposition of Specific Organic Amendments.

Population densities of nematodes in field soil without plants were monitored for 10 months following application of organic amendments to pots in a greenhouse. The four treatments consisted of three different kinds of organic amendments: homogeneous crop residues of maize (Zea mays, C:N = 48.0:1), Texas panicum (Panicum texanum, C:N = 32.9:1), or velvetbean (Mucuna pruriens, C:N = 18.6:1), plus a control without any amendment. Plant-parasitic nematodes declined in all treatments due to absence of a food source. Bacterivore numbers increased following amendment application and remained greater than initial population levels until 4 months after application. Fungivore numbers were higher than initial levels until 6 months after amendment application and did not decline below the initial numbers during the course of the experiment. On several sampling dates, the bacterivorous genera Cervidellus and Eucephalobus were most abundant in pots with maize residues. Among the fungivores, Aphelenchoides numbers early in the experiment were greatest in pots amended with velvetbean, whereas numbers of Aphelenchus, Nothotylenchus, and Tylenchidae (mainly Filenchus) were greatest during the latter half of the experiment following the maize amendment. Omnivorous nematodes, particularly Eudorylaimus, showed two peaks in abundance during the course of the experiment. Results provided some evidence that population levels of some genera of bacterivores and fungivores may be affected by specific organic amendments.

Responses of Some Common Cruciferae to Root-knot Nematodes.

Ten cultivated plants of the family Cruciferae were evaluated for susceptibility to Meloidogyne arenaria race 1, M. incognita races 1 and 3, and M. javanica in a series of four separate greenhouse tests. After 62-64 days, or 1,032-1,072 degree days (10 C base), several of the crops evaluated showed moderate to severe levels of galling (> 3.0 on 0-5 scale) and moderate numbers of egg masses (>2.0 on 0-5 scale) in response to each of the nematode species and races. Among the plants tested, collard (Brassica oleracea var. acephala) cv. Georgia Southern was the least susceptible (fewest galls and egg masses) to each of the four nematode isolates. Similar low levels of infection were obtained with broccoli (B. oleracea var. botrytis) cv. De Cicco in response to M. incognita race 1 and M. arenaria. Numbers of second-stage juveniles hatched from eggs per root system were variable in the test with M. arenaria, but lowest on collard for each of the other nematodes. Some commonly grown crucifers are hosts to several different species and races of Meloidogyne, which should be considered if these crops are included in cropping systems.

Effects of Tropical Rotation Crops on Meloidogyne arenaria Population Densities and Vegetable Yields in Microplots.

The effects of 12 summer crop rotation treatments on population densities of Meloidogyne arenaria race 1 and on yields of subsequent spring vegetable crops were determined in microplots. The crop sequence was: (i) rotation crops during summer 1991 ; (ii) cover crop of rye (Secale cereale) during winter 1991-92; (iii) squash (Cucurbita pepo) during spring 1992; (iv) rotation crops during summer 1992; (v) rye during winter 1992-93; (vi) eggplant (Solanum melongena) during spring 1993. The 12 rotation treatments were castor (Ricinus communis), cotton (Gossypium hirsutum), velvetbean (Mucuna deeringiana), crotalaria (Crotalaria spectabilis), fallow, hairy indigo (Indigofera hirsuta), American jointvetch (Aeschynomene americana), sorghum-sudangrass (Sorghum bicolor x S. sudanense), soybean (Glycine max), horsebean (Canavalia ensiformis), sesame (Sesamum indicum), and peanut (Arachis hypogaea). Compared to peanut, the first eight rotation treatments resulted in lower (P

Response of some common annual bedding plants to three species of meloidogyne.

Twelve ornamental bedding plant cultivars were grown in soil infested with isolates of Meloidogyne incognita race 1, M. javanica, or M. arenaria race 1 in a series of tests in containers in a growth room. Root galling (0-5 scale) and eggs/plant were evaluated 8-10 weeks after soil infestation and seedling transplantation. Snapdragon, Antirrhinum majus cv. First Ladies, was extensively galled and highly susceptible (mean gall rating >/=4.2 and >/=14,500 eggs/plant), and Celosia argentea cv. Century Mix and Coleus blumei cv. Rainbow were susceptible (>1,500 eggs/plant) to all three Meloidogyne isolates. Response of Petunia x hybrida varied with cultivar and nematode isolate. Little or no galling or egg production from any Meloidogyne isolate was observed on Ageratum houstonianum cv. Blue Mink, Lobularia maritima cv. Rosie O'Day, or Tagetes patula cv. Dwarf Primrose. Galling was slight (mean rating 4.0 and >/=7,900 eggs/plant) by M. javanica and M. arenaria but was nearly free of galling from M. incognita. Zinna elegans cv. Scarlet was nearly free of galling from M. incognita and M. arenaria but was susceptible (mean gall rating = 2.9; 3,400 eggs/plant) to M. javanica.

Damage Functions for Meloidogyne arenaria on Peanut.

Microplot experiments were conducted in 1989 and 1990 to determine the relationship between yield of peanut (Arachis hypogaea) and inoculum density ofMeloidogyne arenaria race 1. Nine inoculum densities were used, ranging from 0-200 eggs/100 cm(3) soil (1989) or from 0-100 eggs/100 cm(3) (1990), and each density was replicated 10 times. In 1989, higher final densities (mean of 1,171 juveniles [J2]/100 cm(3) soil) were obtained in plots inoculated with 0.5 to 50 eggs/100 cm(3) soil than in plots inoculated with 100 to 200 eggs/100 cm(3) (313 J2/100 cm(3) soil). In 1990, final densities of M. arenaria reached high levels (>/= 1,111 J2/100 cm(3) soil) in all inoculated plots. Pod yield and dry weight of foliage at harvest were negatively correlated (P

Extraction Efficiency of Belonolaimus longicaudatus from Sandy Soil.

Numbers of Belonolaimus longicaudatus extracted from sandy soils (91-92% sand) by sieving and centrifugation were only 40-55% of those extracted by sieving and incubation on a Baermann tray. Residues normally discarded at each step of the sieving plus Baermann tray extraction procedure were examined for nematodes to obtain estimates of extraction efficiencies. For third-stage and fourth-stage juveniles, males, and females, estimates of extraction efficiency ranged from 60 to 65% in one experiment and 73 to 82% in another. Estimated extraction efficiencies for second-stage juveniles were lower (33% in one experiment, 67% in another) due to losses during sieving. When sterilized soil was seeded with known numbers of B. longicaudatus, 60% of second-stage juveniles and 68-76% of other stages were recovered. Most stages of B. longicaudatus could be extracted from these soils by sieving plus Baermann incubation with an efficiency of 60-70%.

Inhibition of placental aromatase activity in a cell free assay by ovarian protein.

Previously we identified a fraction of follicular fluid (follicle regulatory protein: FRP) which inhibits granulosa cell aromatase activity. During the course of these studies the question of FRP acting via autocrine as well as paracrine mechanisms arose in addition to the need for a more efficient method of screening for aromatase inhibitory activity during the purification of FRP. Accordingly, we assessed the effects of FRP on aromatase activity in a microsomal assay. Placental microsome preparations were preincubated for 20 minutes with or without FRP prior to a 20 minute incubation with testosterone. Significantly less conversion of testosterone to estrogen occurred with FRP compared to control preincubation. When follicular protein was added without pre-incubation, there was no apparent change in microsomal aromatase activity, whereas after a 20 minute pre-incubation with the follicular protein fraction, significantly less testosterone was converted into estrogen. When various concentrations of FRP were assayed in the placental aromatase assay, a dose-response curve demonstrated a 50% inhibitory dose (ID50) of approximately 400 micrograms/ml. To further purify the aromatase inhibitory activity, 5 mg of the crude follicular fluid preparation was eluted through an anion exchange column via HPLC using a sodium acetate gradient. The fractions in the central elution peak contained aromatase inhibitor activity with ID50 values of 25-160 micrograms/ml. Thus Fractions were further purified by elution through a gel exclusion column via HPLC which demonstrated inhibition of cell free placental aromatase activity in the 15,000-18,000 molecular weight range with an ID50 of 5 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Follicle regulatory protein noncompetitively inhibits microsomal 3 beta-hydroxysteroid dehydrogenase activity.

A heat- and trypsin-labile follicular fluid protein (FRP) extracted from both human and porcine follicular fluid has been shown to modulate ovarian steroidogenesis. To further investigate the effects of FRP, its effect on the kinetics of 3 beta-hydroxysteroid dehydrogenase activity (3 beta-HSD) was evaluated in cell-free microsomal preparations from human placenta. Test fractions of follicular fluid protein were preincubated with placental microsomes followed by the addition of various substrate concentrations (pregnenolone + NAD). Subsequent progesterone formation was interpreted as the velocity of the reaction. The 50% inhibitory dose (ID50) of FRP for 3 beta-HSD for the three substrate concentrations was 300 micrograms/ml. Although a clear decrease in 3 beta-HSD activity typically occurred after pre-incubation with 730 micrograms/ml of FRP, a paradoxical augmentation in 3 beta-HSD activity was present with the lower concentrations of FRP (10-30 micrograms/ml) and the more concentrated microsomal preparations. Double reciprocal plots of these reactions demonstrated a Km for 3 beta-HSD of 1.8-2.1 X 10(-6) M. Analysis of all reactions was found to be consistent with a noncompetitive mode of enzyme inhibition with an apparent Ki of 120 ng/ml or approximately 10(-8) M assuming a mol. wt of 16,000 Daltons for FRP. This derived Ki for FRP is within the biological concentration of FRP in follicular fluid.

Initiation of angiogenesis by porcine follicular fluid.

Angiogenesis was observed and measured after injection of porcine follicular fluid into rabbit corneas. A qualitative response (0 to 6+) and quantitative measurement (mm/day) were obtained 9 days after injection. Undiluted porcine follicular fluid stimulated angiogenesis with new blood vessels visible by the third day after injection, extending 2.0 to 3.0 mm into the site of injection from the corneal scleral limbus (1 to 4+) by day 9. Angiogenic activity was consistently found in fractions of porcine follicular fluid which precipitated in 20% to 40% saturated ammonium sulfate. Sephadex gel filtration of the 20% to 40% saturated ammonium sulfate fraction resulted in fractions with molecular weights of 45,000 to 60,000 and less than or equal to 1500 daltons which stimulated angiogenesis. Charcoal treatment of active fractions did not remove angiogenic activity. Angiogenic activity was retained after heating at 56 degrees C for 1 hour but was lost after boiling (20 minutes). Quantitative measurements of chemotaxis with use of Boyden chambers and mitogenesis by means of tritiated thymidine incorporation were performed. Follicular fluid from small follicles contained greater chemotactic activity than follicular fluid from medium or large follicles. The 20% to 40% saturated ammonium sulfate precipitate that eluted through Sephadex G-100 with a molecular weight of 45,000 to 60,000 daltons contained angiogenic, mitogenic, and chemotactic activity. In conclusion, porcine follicular fluid contains angiogenic factors that may be associated with perifollicular neovascularization during folliculogenesis.

Ovulation induction in clomiphene-resistant anovulatory women: differential follicular response to purified urinary follicle-stimulating hormone (FSH) versus purified urinary FSH and luteinizing hormone.

We studied 15 anovulatory women undergoing ovulation induction with purified human urinary FSH or purified human urinary FSH and LH [human menopausal gonadotropins (hMG)]. All patients had either sporadic or no vaginal bleeding after progesterone therapy and failed to ovulate after receiving clomiphene (250 mg for 5 days) plus hCG. Other causes of infertility were ruled out. Sixteen cycles of FSH and 12 cycles of hMG were administered according to a standard protocol. Estradiol, progesterone, androstenedione, testosterone, LH, and FSH concentrations were quantitated by RIA. Follicular diameter was determined using ultrasound. There was no significant difference in the amount of FSH or hMG used per patient, in the duration of therapy before hCG administration, or in the length of the luteal phase in any patient. There was a difference in the number of follicles greater than 1000 mm3 per cycle in those patients receiving FSH compared to the number in those receiving hMG [2.8 +/- 1.3 (+/- SEM) vs. 4.4 +/- 1.5 follicles; P = 0.026). The maximum follicular phase serum estradiol (18.3 vs. 34.8 ng/ml) and maximum luteal phase progesterone concentrations (1289 vs. 2808 pg/ml; P = 0.026) were also different between the FSH and hMG groups. Linear regression analysis revealed a significant correlation between the peripheral serum estradiol levels and the total follicular volume of follicles in the hMG-treated group which was not apparent in the FSH-treated group. These findings suggest that exogenous LH may not be required to induce folliculogenesis in anovulatory patients.

Intraspecific morphological variation among populations of Pratylenchus brachyurus and P. coffeae.

Three populations of Pratylenchus coffeae and two of P. brachyurus, each originating from a single female, were maintained on Citrus spp. or Solanum nigrum L. for several years under greenhouse conditions. Nematodes were extracted from roots, and adult female specimens were killed, fixed, and mounted in glycerine for microscopic study. Variables measured were distance between vulva and anus and lengths of the stylet, posterior uterine sac, and tail. The mean data and coefficients of variability suggest that styler length had the least variability, and length of posterior uterine sac the most. When males and distinct spermathecae are not evident in P. coffeae populations, the species can he distinguished from P. brachyurus by a shorter mean stylet length, longer mean posterior uterine sac length, and much longer distance between the vulva and anus.

Antimicrobial actions of hexachlorophene: inhibition of respiration in Bacillus megaterium.

Hexachlorophene (HCP) inhibits both endogenous and exogenous respiration (oxygen uptake) in Bacillus megaterium, without sparing by any of several substrates. The inhibition is maximal when the cells are treated with 8 mug of HCP per mg of cells (dry weight), which corresponds to the minimal lethal dose. Levels as low as 2 mug/mg are inhibitory but not lethal. HCP also inhibits the respiration of isolated B. megaterium membranes and can act on several components of the electron transport chain in the membranes and on soluble enzymes. Although both forms of nicotinamide adenine dinucleotide, reduced form dehydrogenase and malic dehydrogenase are inhibited by HCP, they are less susceptible than is oxygen uptake. The site of maximal sensitivity is nearer the terminal electron acceptor, but the exact location depends on the cytochrome composition of the membranes. If cytochromes b(1), a, and a(3) are present, but not o, HCP inhibits electron transport on the substrate side of cytochrome b(1); if cytochromes b(1), a(3), and o are present, but not a, the inhibition occurs on the oxygen side of cytochrome b(1). Exogenous menadione, an analogue of menaquinone, reverses the inhibition in both circumstances. The primary lethal action of HCP thus appears to be respiratory inhibition at a site within the membrane-bound part of the electron transport chain.