Suitability of some southern and western pines as hosts for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae).

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that has become established in North America. Discovered in Ohio in 1992, it has since been found in at least 13 states and parts of Canada. The beetle can cause significant growth loss in pines, and it represents a potential threat to trees in areas where it has not yet become established. To evaluate this threat to native pines, field and laboratory tests were conducted on several common and important southern and western species to determine whether they are acceptable hosts for T. piniperda. Comparisons with Pinus sylvestris L., Scots pine, a preferred natural host for the beetle, were made where possible. Measurements of beetle attack success on southern pine billets showed that Pinus taeda L., Pinus echinata Miller, Pinus elliottii var. elliottii Engelmann, Pinus palustris Miller, and Pinus virginiana Miller (loblolly, shortleaf, slash, longleaf, and Virginia pine, respectively) and two western pines, Pinus ponderosa Lawson and Pinus contorta Douglas (ponderosa and lodgepole pine, respectively), were acceptable for breeding material, but brood production was highly variable. Among the southern pines, P. taeda and P. echinata were susceptible to shoot feeding by T. piniperda, whereas P. elliottii was highly resistant and P. palustris seemed to be virtually immune. Shoot feeding tests on the western pines were conducted only in the laboratory, but there was moderate-to-good survival of adults feeding on both species. It seems that if T. piniperda is introduced into the south and west it will likely establish and may cause some damage to native pines. P. taeda may be affected more than other southern pines because it is the most abundant species, it is readily attacked for brood production, which can result in moderately large broods, and the beetle survives well during maturation feeding on P. taeda shoots.

Tomicus piniperda (Coleoptera: Scolytidae) shoot-feeding characteristics and overwintering behavior in Scotch pine Christmas trees.

Overwintering behavior of Tomicus piniperda (L.) was studied in a Scotch pine (Pinus sylvestris L.) Christmas tree plantation in Indiana (1992-1994) and a plantation in Michigan (1994). In general, adults feed inside shoots during summer, then move to overwintering sites at the base of trees in autumn. In early autumn, adults were most often found in shoot-feeding tunnels that were still surrounded by green needles, whereas few were in tunnels surrounded by yellow or brown needles. For all years and sites combined, the range in the percentage of recently tunneled shoots that contained live T. piniperda adults decreased from 89 to 96% in mid-October, to 15- 66% in early November, to 2-10% in mid-November, and to 0-2% by late November to early December. In each year, the first subfreezing temperatures in autumn occurred in October, before most adults left the shoots. Of 1,285 T. piniperda-tunneled shoots, one to seven tunnels (mean = 1.6) and zero to three adults were found per infested shoot. Of these 1,285 attacked shoots, 55% of the shoots had one tunnel, 33% had two, 9% had three, 3% had four, and <1% had five to seven tunnels each. When two or more tunnels occurred in a single shoot, adults were most commonly found in the innermost (most basal) tunnel. For the 2,070 tunnels found in the 1,285 shoots, average shoot thickness at the tunnel entrance was 6.0 mm, average distance from the tunnel entrance to the shoot tip was 6.3 cm, and average tunnel length was 2.3 cm. Four Scotch pine Christmas trees were dissected in January 1993. Eighty percent of the tunneled shoots were in the upper quarter of the tree crown and 98% were in the upper half. For the four trees inspected in January, one live adult was found in a shoot and 85 adults were found in the outer bark along the lower trunk from 1 cm below the soil line to 19 cm above the soil line. No overwintering adults were found outside the trunk in the duff or soil near the base of each test tree. Implications of these results are discussed in terms of surveying, timing the cutting of Christmas trees, and cutting height for Christmas trees.

Tomicus piniperda (Coleoptera: Scolytidae) emergence in relation to burial depth of brood logs.

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest of pines, Pinus spp., that was first found in the United States in 1992. A federal quarantine currently regulates movement of pine Christmas trees and pine nursery stock from infested to uninfested counties. The current national Pine Shoot Beetle Compliance Management Program requires T. piniperda-infested brood material to be disposed of by burning, chipping, or burial. The burial option requires that the infested pine material be buried at a depth of at least 30 cm. We tested this requirement by burying logs with similar levels of infestation at 0, 15, 30, 45, 61 and 76 cm and then monitoring for T. piniperda emergence. Logs were buried at two times during larval development (early and late) and in two soil types (sandy loam and loam). Emergence patterns from the two soil types were similar. Overall, 1,747 T. piniperda adults were collected from the 24 exposed control logs, but only 34 adults from the 120 buried logs, including 24 adults from logs buried at 15 cm, eight adults from 30 cm, one adult from 45 cm, and one adult from 61 cm. In comparing mean emergence density from buried logs with that of exposed logs, 98.6% mortality occurred at 15 cm, 99.5% at 30 cm, and > 99.9% at > or = 45 cm. Mean date of T. piniperda emergence to the soil surface was affected by burial depth and burial date, but not soil type.

Structure-activity relationship studies on 1-[2-(4-Phenylphenoxy)ethyl]pyrrolidine (SC-22716), a potent inhibitor of leukotriene A(4) (LTA(4)) hydrolase.

Leukotriene B(4) (LTB(4)) is a pro-inflammatory mediator that has been implicated in the pathogenesis of a number of diseases including inflammatory bowel disease (IBD) and psoriasis. Since the action of LTA(4) hydrolase is the rate-limiting step for LTB(4) production, this enzyme represents an attractive pharmacological target for the suppression of LTB(4) production. From an in-house screening program, SC-22716 (1, 1-[2-(4-phenylphenoxy)ethyl]pyrrolidine) was identified as a potent inhibitor of LTA(4) hydrolase. Structure-activity relationship (SAR) studies around this structural class resulted in the identification of a number of novel, potent inhibitors of LTA(4) hydrolase, several of which demonstrated good oral activity in a mouse ex vivo whole blood assay.

Genetic relatedness of North American populations of Tomicus piniperda (Coleoptera:Scolytidae).

We used DNA fingerprinting by random amplified polymorphic (RAPD) DNA and electrophoretic characterization of esterase isozymes to investigate the genetic relatedness of North American populations of the exotic bark beetle Tomicus piniperda (L.). Cluster analyses of genetic distances among populations identified the Illinois population as an outlier population with mean genetic distances to other populations averaging 0.895 (where complete dissimilarity = 2), compared with genetic distance averages of 0.595 among populations excluding Illinois. When genetic distance means and geographical distance between populations were compared, the results suggested that T. piniperda populations in the United States were established separately in Illinois near Lake Michigan and in Ohio along Lake Erie. Molecular markers indicated that insects derived from the 2 founder groups were interbreeding in contiguous regions in western Indiana.

The leukotriene B4 receptor agonist/antagonist activities of SC-45694 in human neutrophils.

SC-45694 (7-[4-(1-hydroxy-3Z-nonenyl)phenyl]-5S-hydroxy-6Z-hept enoic acid lithium salt), a representative of a new class of leukotriene B4 (LTB4) analogs that are conformationally restricted, was evaluated for effects on human neutrophil functions. SC-45694 inhibited [3H] LTB4 binding to the high-affinity receptors on human neutrophils with a KD value of 0.76 microM, but it was a very weak inhibitor of [3H]N-formyl-methionyl-leucyl-phenylalanine binding (KD > 83 microM). SC-45694 stimulated neutrophil chemotaxis with half-maximal and maximal effects at 1 and 10 microM, respectively, and produced a maximal chemotactic response similar to that produced by LTB4. The chemotactic activity of SC-45694 was blocked by the LTB4 receptor antagonists SC-41930 and LY-255283. At concentrations that showed agonist activity for neutrophil chemotactic response, SC-45694 showed no agonist activity for degranulation, antagonized LTB4-induced degranulation and inhibited [3H] LTB4 binding to low-affinity receptors. SC-45694 inhibited LTB4-induced maximal degranulation with an IC50 value of 0.3 microM, but it did not inhibit N-formyl-methionyl-leucyl-phenylalanine-induced degranulation. The inhibition by SC-45694 of LTB4-induced degranulation was time-dependent, noncompetitive and reversible. Thus SC-45694 exhibited a specific, full LTB4 agonist activity for chemotaxis and an antagonist activity against LTB4-induced degranulation. These properties suggest that members of the new class of LTB4 analogs, such as SC-45694, may be useful in further characterizing distinct LTB4 receptor subtypes that mediate these two neutrophil functions.

Variation in semiochemical-mediated prey-predator interaction:Ips pini (Scolytidae) andThanasimus dubius (Cleridae).

The bark beetleIps pini (Say) displays variation in its response to and production of enantiomeric blends of its pheromone ipsdienol. One of the principal predators ofIps pini isThanasimus dubius (F.), which uses ipsdienol as a kairomone for prey location. During 1988 and 1989, in Wisconsin and Michigan, the response of both species to a range of enantiomeric blends of ipsdienol was investigated. Blends tested had the following ratios of the (S)-(+) to (R)-(-) enantiomers: 3%∶97%, 25%∶75%, 50%∶50%, 75%∶ 25%, and 97%∶ 3%. Either 75% (+)∶25% (-) or 50% (+)∶50% (-) ipsdienol captured the mostIps pini in both years at both sites. The 25% (+)∶75% (-) blend also caught moreIps pini than the control during both years at both sites. All blends tested were attractive toThanasimus dubius in both years at both locations. Blend preferences of both species were variable and labile at both sites. Response patterns of both species in Wisconsin were different from those in Michigan each year. Furthermore, response patterns of both species to the ipsdienol blends changed from 1988 to 1989 at both locations. A genetic component to this variation would permit predator-prey coevolution, as well as the development of resistance byIps pini to management strategies based on mass-trapping with single blends.

Variation in semiochemical-mediated prey-predator interaction:Ips pini (Scolytidae) andThanasimus dubius (Cleridae).

The bark beetleIps pini (Say) displays variation in its response to and production of enantiomeric blends of its pheromone ipsdienol. One of the principal predators ofIps pini isThanasimus dubius (F.), which uses ipsdienol as a kairomone for prey location. During 1988 and 1989, in Wisconsin and Michigan, the response of both species to a range of enantiomeric blends of ipsdienol was investigated. Blends tested had the following ratios of the (S)-(+) to (R)-(-) enantiomers: 3%∶97%, 25%∶75%, 50%∶50%, 75%∶25%, and 97%∶3%. Either75% (+) ∶ 25% (-) or 50% (+)∶ 50% (-) ipsdienol captured the mostIps pini in both years at both sites. The 25% (+)∶75% (-) blend also caught moreIps pini than the control during both years at both sites. All blends tested were attractive toThanasimus dubius in both years at both locations. Blend preferences of both species were variable and labile at both sites. Response patterns of both species in Wisconsin were different from those in Michigan each year. Furthermore, response patterns of both species to the ipsdienol blends changed from 1988 to 1989 at both locations. A genetic component to this variation would permit predator-prey coevolution, as well as the development of resistance byIps pini to management strategies based on mass-trapping with single blends.

Differential effects of 20-trifluoromethyl leukotriene B4 on human neutrophil functions.

A leukotriene B4 (LTB4) analog, 20-trifluoromethyl LTB4 (20CF3-LTB4), has been synthesized and evaluated with human neutrophils for effects on chemotaxis and degranulation. 20CF3-LTB4 was equipotent to LTB4 as a chemoattractant (EC50, 3 nM), produced 50% of maximal activity of LTB4, and competed with [H] LTB4 for binding to intact human neutrophil LTB4 receptors. In contrast to chemotactic activity, 20CF3-LTB4 in nanomolar concentrations exhibited antagonist activity without agonist activity up to 10 microM on LTB4-induced degranulation. The analog had no significant effect on degranulation induced by the chemoattractant peptide, N-formyl-methionyl-leucyl-phenylalanine (fMLP). Like LTB4, 20CF3-LTB4 induced neutrophil desensitization to degranulation by LTB4. The results indicate that hydrogen atoms at C-20 of LTB4 are critical for its intrinsic chemotactic and degranulation activities. The fact that 20CF3-LTB4 is a partial agonist for chemotaxis and an antagonist for degranulation suggests that different LTB4 receptor subtypes are coupled to these neutrophil functions. Desensitization of the neutrophil degranulation response to LTB4 can result from receptor occupancy by an antagonist, and therefore, the desensitization is not specific for an agonist.

Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase.

A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue. The potency showed a correlation to the calculated pKa of the aniline nitrogen atom. Substitutions on the aniline and benzimidazole rings did not further enhance potency. Di- and trisubstituted aniline derivatives were potent inhibitors of the enzyme system. The preferred combination of substituents were a methoxy group on the benzimidazole ring and a single alkyl group on the aniline ring. One such compound, 76, was an effective inhibitor of acid secretion in the dog and was selected for further pharmacological study.

Plasticity in life-history traits of the bark beetle Ips calligraphus as influenced by phloem thickness.

Reproduction and development of Ips calligraphus (Germar) (Coleoptera: Scolytidae) occur primarily in the phloem (inner bark) tissue of its pine hosts. In slash pine (Pinus elliottii Engelm. var. elliottii), phloem thickness can vary widely from tree to tree. We compared adult residence time and fecundity and progeny development time, body size, and sex ratio of this beetle when reared in slash pine bolts and bark slabs with phloem thicker or thinner than average adult body width. Most studies were conducted at 20°, 25°, and 30° C. Residence time of parent males and females decreased with increasing temperature but it was not affected by phloem thickness. Residence time of parent males was about 2 days shorter than that of parent females at each temperature. Reproductive fitness was greater in thick phloem at all temperatures as measured by faster larval development, earlier emergence of progeny (F 1 ) adults, and emergence of more progeny adults per parent female. Progeny survival was similar between phloem those from thick phloem, and their sex ratio was female biased (1:2 vs 1:1, male:female). When allowed to inhabit thick phloem, the progeny (F 2) of adults from thin phloem were just as large and of similar sex ratio (1:1) as were progeny of F 1 adults from thick phloem. The high degree of plasticity in the life-history traits of this beetle may enable it to successfully colonize pines that vary widely in phloem thickness.