Log colonization by Ips sexdentatus prevented by increasing host unsuitability signaled by verbenone

Sudden increments of breeding material after windstorms, forest fires, or inappropriate management practices help bark beetles such as Ips sexdentatus Boerner (Coleoptera: Curculionidae: Scolytinae) increase in numbers and colonize standing healthy pine trees. Preventing bark beetles from arriving to susceptible trees or logs may have great relevance for bark beetle management. Recent studies have reported inhibition of the aggregation response of I. sexdentatus using verbenone. Two field experiments were conducted to examine the effect of verbenone on the colonization pattern of this beetle. The first experiment tested the combined effect of trans‐conophthorin, a non‐host bark volatile with known repellent effect, and verbenone on Pinus sylvestris L. (Pinaceae) log piles of two sizes, but failed to protect them against I. sexdentatus attack when these two infochemicals were released at low rates. The results of this experiment suggested an interaction with the associated secondary bark beetle Orthotomicus erosus (Wollaston). A second experiment examined the response of I. sexdentatus and O. erosus to log piles that released verbenone at 0, 2, 10, or 40 mg day^?1. Although I. sexdentatus colonization of Pinus nigra Arnold logs was completely prevented at 40 mg day^?1, O. erosus could be found at all tested verbenone release rates. Besides verbenone, O. erosus colonization density and the height from which logs originated were the variables that best explained I. sexdentatus log colonization pattern. In addition, I. sexdentatus and O. erosus were rarely recorded colonizing the same log, and niche breadth analyses suggested that they excluded each other. The role of verbenone in the colonization process and its potential use in the prevention of population buildups of damaging bark beetles such as I. sexdentatus are discussed.     

Polarity induced by chloramphenicol and relief by suA

The suA allele, known to relieve polarity in Escherichia coli, also relieves a unique polar effect on E. coli tryptophan operon messenger RNA produced by chloramphenicol.     

Inactivation of Bacteriophages by ε-Poly-l-lysine Produced by Streptomyces

Degradation of a β-O-4lignin substructure model dimer by a white rot fungus, Phanerochaete chrysosporium, was investigated using a culture containing H₂¹⁸O, and the following conclusions were made. a) The direct hydrolysis at C_β of the β-O-4 dimer was not involved in formation of arylglycerol. b) About half of the oxygen at the benzyl (C_α) position of the glycerol was derived from H₂O (H₂¹⁸O) and the other half was from the oxygen at the benzyl (C_α) position of the substrate β-O-4 dimer. c) But, the oxygen at the C_α position of the substrate β-O-4 dimer did not migrate to the C_α position of the aryglycerol.     

Oviposition by Lobesia botrana is stimulated by sugars detected by contact chemoreceptors

Abstract.  The influence of glucose, fructose and sucrose on oviposition site selection by Lobesia botrana is studied by combining behavioural and electrophysiological experiments. Oviposition choice assays, using surrogate grapes treated with grape berry surface extracts of Vitis vinifera cv. Merlot at different development stages, show that L. botrana females are most stimulated by extracts of mature berries containing the highest concentrations of glucose and fructose. Choice assays reveal that the oviposition response to these sugars is dose-dependant (with a threshold of the applied solution = 10 m m and a maximum stimulation at 1  m ) and that females are more sensitive to fructose than to glucose. Tarsal contact-chemoreceptor sensilla are unresponsive to stimulation with sugars but the ovipositor sensilla contain at least one neurone most sensitive to fructose and sucrose with a threshold of approximately 0.5 m m . Corresponding to the behavioural data, glucose is significantly less stimulatory to sensilla than fructose or sucrose. It is argued that fructose may be of special importance for herbivorous insects exploiting fruit as an oviposition site.     

Prostaglandin synthesis by rheumatoid synovium and its stimulation by colchicine

The synthesis of prostaglandins by rheumatoid synovial tissue in organ culture was studied utilizing radioimmunoassay, with antisera to PGB₁, PGF_1α and PGF_2α. It was established that PGE₂ and PGF_2α were the major prostaglandins formed by analyses of culture media with the two antisera to PGF, before and after alkali treatment. Indomethacin at 5 μg/ml suppressed prostaglandin synthesis, usually to <1% of control cultures. Colchicine, 0.1 μg/ml resulted in marked stimulation of prostaglandin synthesis, in some cases over 10 fold. It is suggested, because of the colchicine effect, that the state of the microtubules may regulate the rate of prostaglandin biosynthesis. It is possible that prostaglandin E₂ produced by rheumatoid synovia may contribute to the pathogenesis of the inflammatory reaction and lead to destruction of juxta-articular bone in rheumatoid arthritis.     

Thiocyanate degradation by Acremonium strictum and inhibition by secondary toxicants

Acremonium strictum, capable of degrading 7.4 g thiocyanate l^–1, was isolated from wastewater condensate from coke-oven gas. Ammonia and sulfate were the final products from thiocyanate degradation with a stoichiometric ratio of near 1:1. The highest degradation activity was at pH 6. Although the degradation rate started to be inhibited above 4 g thiocyanate l^–1, thiocyanate was completely degraded up to 7.4 g l^–1 within 85 h in shake-flask cultures. The degradation of thiocyanate was inhibited by phenol above 625 mg l^–1, by cyanide above 16 mg l^–1, and by nitrite above 100 mg l^–1. However, ammonia and nitrate had negligible inhibition on thiocyanate degradation up to 3 g l^–1 and 1.5 g l^–1, respectively.     

Sampling for aphids by traps and by crop inspection

The catches of thirty aphid genera and species during 3 years in a suction trap at 40 ft and on a yellow cylindrical sticky trap at 5 ft at Rothamsted and Broom's Barn are tabulated. Suction-trap catches were the more consistent but both were more effective at recording the first seasonal immigration of Myzuspersicae (Sulz.) and Aphis fabae Scop, than the British Sugar Corporation crop-inspection scheme. The catches show the differential attraction to yellow by different species, the effects of local vegetation, and the seasonal distribution of aphids that are crop pests or potential vectors of viruses.     

Prostaglandin synthesis by rheumatoid synovium and its stimulation by colchicine

The synthesis of prostaglandins by rheumatoid synovial tissue in organ culture was studied utilizing radioimmunoassay, with antisera to PGB₁, PGF_1α and PGF_2α. It was established that PGE₂ and PGF_2α were the major prostaglandins formed by analyses of culture media with the two antisera to PGF, before and after alkali treatment. Indomethacin at 5 μg/ml suppressed prostaglandin synthesis, usually to <1% of control cultures. Colchicine, 0.1 μg/ml resulted in marked stimulation of prostaglandin synthesis, in some cases over 10 fold. It is suggested, because of the colchicine effect, that the state of the microtubules may regulate the rate of prostaglandin biosynthesis. It is possible that prostaglandin E₂ produced by rheumatoid synovia may contribute to the pathogenesis of the inflammatory reaction and lead to destruction of juxta-articular bone in rheumatoid arthritis.     

Mobilization of iron by phytosiderophores as affected by other micronutrients

It has been shown previously (Treeby et al., 1989) that phytosiderophores, released by roots of iron deficient grasses (Gramineae), mobilize from calcareous soils not only iron (Fe) but also zinc (Zn), manganese (Mn) and copper (Cu). Mobilization of Fe may therefore be impaired by other micronutrient cations. This has been studied in both, model experiments with Fe hydroxide and with a calcareous soil (15% CaCO₃, pH 8.6) amended with micronutrients as sulfate salts.Mobilization of Fe from Fe hydroxide by phytosiderophores (epi-3-hydroxymugineic acid) was not affected by the addition of CaCl₂, MgSO₄ and MnSO₄, slightly inhibited by ZnSO₄ and strongly inhibited by CuSO₄. In a calcareous soil amended with increasing levels of ZnSO₄, MnSO₄ and CuSO₄, mobilization of Fe by phytosiderophores remained uneffected by Zn and Mn amendments but was progressively impaired by increasing levels of Cu amendment, correlated with corresponding enhancement of Cu mobilization.High concentrations of ZnSO₄ and MnSO₄ and relatively high concentrations of CuSO₄ were required for inhibition of Fe mobilization by phytosiderophores. It is therefore concluded that in most calcareous soils phytosiderophores efficiently mobilize Fe, and that phytosiderophores play an important role in Fe acquisition by grasses grown on calcareous soils.     

Ferrihydrite reduction by Geobacter species is stimulated by secondary bacteria

Geobacter species such as G. bremensis, G. pelophilus, and G. sulfurreducens are obligately anaerobic and grow in anoxic, non-reduced medium by fast reduction of soluble ferric citrate. In contrast, insoluble ferrihydrite was either only slowly or not reduced when supplied as electron acceptor in similar growth experiments. Ferrihydrite reduction was stimulated by addition of a reducing agent or by concomitant growth of secondary bacteria that were physiologically and phylogenetically as diverse as Escherichia coli, Lactococcus lactis, or Pseudomonas stutzeri. In control experiments with heat-inactivated Geobacter cells and viable secondary bacteria, no (E. coli, P. stutzeri) or only little (L. lactis) ferrihydrite was reduced. Redox indicator dyes showed that growing E. coli, P. stutzeri, or L. lactis cells lowered the redox potential of the medium in a similar way as a reducing agent did. The lowered redox potential was presumably the key factor that stimulated ferrihydrite reduction by all three Geobacter species. The observed differences in anoxic non-reduced medium with ferric citrate versus ferrihydrite as electron acceptor indicated that reduction of these electron acceptors involved different cellular components or different biochemical strategies. Furthermore, it appears that redox-sensitive components are involved, and/or that gene expression of components needed for ferrihydrite reduction is controlled by the redox state.Dedicated to Prof. Dr. Dr. h.c. mult. Hans Günter Schlegel on the occasion of his 80th birthday.     

Superoxide Anion Production by Human Neutrophils Activated by Trichomonas vaginalis

Neutrophils are the predominant inflammatory cells found in vaginal discharges of patients infected with Trichomonas vaginalis. In this study, we examined superoxide anion (O₂^.-) production by neutrophils activated by T. vaginalis. Human neutrophils produced superoxide anions when stimulated with either a lysate of T. vaginalis, its membrane component (MC), or excretory-secretory product (ESP). To assess the role of trichomonad protease in production of superoxide anions by neutrophils, T. vaginalis lysate, ESP, and MC were each pretreated with a protease inhibitor cocktail before incubation with neutrophils. Superoxide anion production was significantly decreased by this treatment. Trichomonad growth was inhibited by preincubation with supernatants of neutrophils incubated for 3 hr with T. vaginalis lysate. Furthermore, myeloperoxidase (MPO) production by neutrophils was stimulated by live trichomonads. These results indicate that the production of superoxide anions and MPO by neutrophils stimulated with T. vaginalis may be a part of defense mechanisms of neutrophils in trichomoniasis.     

Blood lead level distribution by by age group in Japanese

Blood lead levels of 634 healthy Japanese (422 males and 212 females), aged 0–87, living in the Kyushu and Okinawa Islands, were determined by the colorimetric dithizone method and atomic absorption spectrometry. The lead level in the atmospheric environment was not extremely high; it was below 1 μg/m³ in most of the places examined. The differences in the geometric means of blood lead levels between 0–5 yr and other age groups were statistically significant (P<0.01). The blood lead levels of Japanese seem to increase in late teens and then decrease slowly to a steady state. The accumulation of lead taken from food was calculated by assuming the amount of lead from food corresponds to the caloric intake recommended for each Japanese age group (e.g., assuming 150 μg/2700 kcal for boys in late teens). Lead concentration in the air was assumed to be 1 μg/m³. The pattern of lead accumulation in blood by age was similar to the theoretical curve for the accumulated total amount of lead obtained by simulation. The fact probably indicates that blood lead levels in Japanese are dependent on lead in daily foods rather than on lead in the atmospheric environment.     

Nitrate absorption by corn roots : inhibition by phenylglyoxal

Nitrate transport in excised corn (Zea mays L.) roots was inhibited by phenylglyoxal, but not by 4,4′-diisothiocyano-2,2′-stilbene disulfonic acid (DIDS) or fluorescein isothiocyanate (FITC). Inhibition of nitrate uptake by a 1-hour treatment with 1 millimolar phenylglyoxal was reversed after 3 hours, which was similar to the time needed for induction of nitrate uptake. If induction of nitrate uptake occurs by de novo synthesis of a nitrate carrier, then the resumption of nitrate uptake in the inhibitor-treated roots may occur because of turnover of phenylglyoxal-inactivated nitrate carrier proteins. All three chemicals inhibited chloride uptake to varying degrees, with FITC being the strongest inhibitor. While inhibition due to DIDS was reversible within 30 minutes, both FITC and phenylglyoxal showed continued inhibition of chloride uptake for up to 3 hours after removal from the uptake solution. Assuming that the anion transporter polypeptide(s) carries a positive charge density at or near the transport site, the results indicate that the nitrate carrier does not carry any lysyl residues that are accessible to DIDS or FITC, whereas the chloride carrier does. Both chloride and nitrate carriers, however, seem to possess arginyl residues that are accessible to phenylglyoxal.     

Reversal by pressure of seed germination promoted by anesthetics

Germination of Panicum capillare L. caryopses induced by solutions of ethanol and ethyl ether was prevented by application of pressure >1 MPa during the period of exposure to the anesthetic. This effect of pressure indicates that germination is correlated with expansion at a site of anesthetic action in a cell membrane. The effects of several other anesthetics were measured on germination of P. capillare seeds. Ethanol, chloroform, and ethyl ether had the highest activity. Methanol and isopropanol were inactive. The effective compounds are thought to distribute preferentially to lipid-solution interfaces in cell membranes of the seeds.     

Biotransformation of cholesterol by Micrococcus species mediated by plasmid DNA

A steroid-biotransforming strain RJ6 was identified as Micrococcus roseus. This bacterium has a 10kb plasmid pMQV10. Curing mediated through cultivation of the culture with a low concentration (200ng/ml) of mitomycin C is described. Loss of cholesterol degradation (chol⁺) and streptomycin resistance (Sm^r) phenotypes as a consequence of the loss of plasmid indicate the extrachromosomal location of these two genes in this strain. An electroporation procedure was developed for transformation of cured strain of Micrococcus (RJC6) by plasmids. Frequency of greater than 10⁵ transformants/g DNA was achieved, which is 100-fold higher than the standard transformation procedure that yielded 5.3×10³ transformants/g DNA in the same strain.     

Cellular uptake of nickel by NikR is regulated by phase separation

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Molybdate and tungstate transfer by rat ileum competitive inhibition by sulphate

For both MoO₄²⁻ and WO₄²⁻ the maximum rate of uptake by the small intestine of the rat (studied in vitro using the everted sac technique) occurs in the lower ileum. Kinetic constants, derived by a least squares procedure, are compared with those previously obtained for SO₄²⁻ transport. For both V and K_a, SO₄²⁻ > MoO₄²⁻ > WO₄²⁻, with only small differences between sacs IV and V. Mutual inhibition of MoO₄²⁻ and WO₄²⁻ transport and inhibition of both by SO₄²⁻ are competitive processes. This is shown by the generally good agreement between K_a values and derived K_i values and by V values in the presence and absence of the inhibiting species. The three ions SO₄²⁻, MoO₄²⁻ and WO₄²⁻ are probably transferred across the intestine by a common carrier system. Implications for the sulphate-molybdenum interaction in molybdosis are discussed.     

Tryptophan uptake by Mycobacterium tuberculosis H37Rv--inhibition by isoniazid.

The effect of various sub-inhibitory concentrations of isoniazid on tryptophan uptake by $\text{Mycobacterium tuberculosis}$ H₃₇Rv grown $\text{in vitro}$ and $\text{in vivo}$ was studied. Uptake, measured after 3 minutes of drug exposure was inhibited mildly by 0.1 μg/ml and 0.2 μg/ml concentration and completely by 0.3 μg/ml. However, with the minimal inhibitory concentration (MIC)⁷ of 0.5 μg/ml, not only inhibition but also a strong efflux of the preformed tryptophan pool were observed. The results are discussed in the light of the theory that isoniazid interferes with the cell wall mycolate synthesis.     

Pathways of hydrocarbon dissimilation by aPseudomonas as revealed by chloramphenicol

Pseudomonas aeruginosa cells pre-grown on a particular hydrocarbon will oxidize other hydrocarbons as well. Degradation of these hydrocarbons proceeds to a point — depending on their structure — where new enzymes are needed for further degradation. Lack of these enzymes causes accumulation of products. However, secondary adaptation processes tend to decrease yields of intermediates, in particular when adaptation rates are high.By inhibiting these secondary adaptation processes with chloramphenicol (CAM), the amounts of various intermediates could be increased.Propionic acid was accumulated from heptane by hexane-grown cells in yields up to 60% (molar) calculated on heptane converted. The effect of CAM suggests that propionic acid is not subject to -oxidation (acrylate pathway) but is degraded via methylmalonate by adaptive enzymes.2-Methylhexane was converted for 30–40% (molar) intoiso-valeric acid by heptane-grown cells. A known pathway ofiso-valeric acid oxidation incorporates a carbon dioxide fixation step, and lack of this enzyme in heptane-grown cells probably causesiso-valeric acid accumulation.Heptene-1 incubation with heptane-grown cells resulted in a 30–40% conversion into 4-pentenoic plus 2, 4-pentadienoic acids. 6-Heptenoic acid was detected occasionally. A predominant attack at C₇ of the heptene-1 molecule is indicated at least for heptane-grown cells. Attack on the saturated end of the molecule seems well in line with the assumption that alkane oxidation by these bacteria is effected by oxygen transferring enzymes operating on a methyl group, as opposed to the action of a dehydrogenase and formation of an -olefin as the intermediate.     

DNA measurement by mithramycin fluorescence in chromatin solubilized by heparin

The mithramycin fluorescence procedure described by B. T. Hill and S. Whatley (1975, FEBS Lett., 56, 20–23) for DNA measurement tends to underestimate DNA concentrations in biological samples as compared to the results obtained by the diphenylamine reaction. This discrepancy disappears when DNA is first solubilized, by buffer containing heparin, from either cell homogenates or nuclear preparations. The optimal conditions for maximal fluorescence are 8 mm Mg²⁺, 10 μg/ml mithramycin, and heparin to DNA ratios ≥0.15 ($\text{w}\text{w}$). Background fluorescence is reduced 90% by dextran-coated charcoal adsorption of unbound mithramycin. The limit of sensitivity of the assay is 0.3 μg/ml and fluorescence is linear up to 30 μg DNA/ml.