Cobweb management and control of the spider Holocnemus pluchei (Araneae: Pholcidae) on buildings

The spider Holocnemus pluchei (Scopoli) (Araneae: Pholcidae) is a nonnative species commonly found in the southwestern United States. In urban areas around homes and other structures, it is often the dominant spider species on outside surfaces; requests for control of spiders and their cobwebs are common for the commercial pest management industry. We tested two physical (brushing and vacuuming) and two low-impact chemical (permethrin and botanical insecticide) spray control methods for H. pluchei on outbuildings on the University of California-Riverside campus. Forty sites containing at least two H. pluchei spiders along a 5-m section of eave or overhang were chosen for treatment. Treatment was applied within 2 d of a pretreatment census. The number of spiders per section was counted at 2, 4, 8, 12, 16, and 52 wk posttreatment. Untreated sections showed an increase in spiders through summer and a decrease in autumn. Sites treated with permethrin significantly reduced spiders >95% and had strong residual effect throughout the remainder of the sampling period. Compared with untreated controls, the three other treatments did not significantly reduce spiders; these three were similar throughout the season and were intermediate between untreated and permethrin-treated sites. In comparison with the before and 2-wk posttreatments, spiders at the untreated sites showed no difference in body sizes, whereas those in the nonpermethrin treatments showed a decrease, indicating that larger spiders were eliminated. We also tested H. pluchei spiders in the laboratory against the two insecticides used in the field studies to determine the minimum lethal concentrations for controlling H. pluchei.     

New insights into pectin methylesterase structure and function

In bacteria, fungi and plants, pectin methylesterases are ubiquitous enzymes that modify the degree of methylesterification of pectins, which are major components of plant cell walls. Such changes in pectin structure are associated with changes in cellular adhesion, plasticity, pH and ionic contents of the cell wall and influence plant development and stress responses. In plants, pectin methylesterases belong to large multigene families, are regulated in a highly specific manner, and are involved in vegetative and reproductive processes, including wood and pollen formation, in addition to plant-pathogen interactions. Although, overall, protein structures are highly conserved between isoforms, recent data indicate that structural variations might be associated with the targeting and functions of specific pectin methylesterases.     

Endothelial cell junctions

In the course of a freeze-cleave study on intercellular junctions in the regenerating rat liver, we observed an unusual array of intramembranous particles located in regions of contact between endothelial cells lining the hepatic sinusoids. These arrays were characterized by an accumulation of particles which resembled a zonula occludens in their linear deployment but differed in that the contact regions were composed of individual particles which remained separated from each other by regular particle-free intervals.     

Expression of the oligopeptide transporter, PepT1, in larval Atlantic cod (Gadus morhua)

The intestinal absorption of di- and tri-peptides generally occurs via the oligopeptide transporter, PepT1. This study evaluates the expression of PepT1 in larval Atlantic cod (Gadus morhua) during the three weeks following the onset of exogenous feeding. Larval Atlantic cod were fed either wild captured zooplankton or enriched rotifers. cDNA was prepared from whole cod larvae preceding first feeding and at 1000 each Tuesday and Thursday for the following three weeks. Spatial and temporal expression patterns of PepT1 mRNA were compared between fish consuming the two prey types using in situ hybridization and quantitative real-time PCR. Results indicated that PepT1 mRNA was expressed prior to the onset of exogenous feeding. In addition, PepT1 was expressed throughout the digestive system except the esophagus and sphincter regions. Expression slightly increased following first-feeding and continued to increase throughout the study for larvae feeding on both prey types. When comparing PepT1 expression in larvae larger than 0.15-mg dry mass with expression levels in larvae prior to feeding, no differences were detected for larvae fed rotifers, but the larvae fed zooplankton had significantly greater PepT1 expression at the larger size. In addition, PepT1 expression in the zooplankton fed larvae larger than 0.15-mg dry mass had significantly greater expression than rotifer fed larvae of a similar weight. Switching prey types did not affect PepT1 expression. These results indicate that Atlantic cod PepT1 expression was slightly different relative to dietary treatment during the three weeks following first-feeding. In addition, PepT1 may play an important role in the larval nutrition since it is widely expressed in the digestive tract.     

Thermopsis thermophila n. gen. n. sp. from hot springs in Nevada, U.S.A. (Crustacea, Ostracoda)

Thermopsis thermophila n. gen. n. sp., a new freshwater ostracod species is described from hot springs in Nevada, U.S.A. The animals were collected within a temperature range of 40–55°C. The new genus belongs to the Ostracoda Podocopida Cypridoidea Cyprididae Cypridopsinae.     

Determining the foraging range and origin of resurgence after treatment of Argentine ant (Hymenoptera: Formicidae) in urban areas

The foraging range and distribution of Argentine ant, Linepithema humile (Mayr), colonies in urban areas of southern California extended at least 61 m (200 feet) from feeding stations and structures. Ants were fed at 25% sucrose feeding stations containing 0.01% fluorescent brighter (FB28). Within 14 d, from 77-90% of the ants sampled next to the feeding stations were positive for FB28. The percentage of ants with FB28 declined gradually to approximately 55% 61 m away from the feeding station. The percentage of marked ants in the controls didn't change over the 4-wk-test period. There were approximately 290,000 ants visiting the monitored stations each night before treatments. The 0.0001% fipronil baits and 0.06% fipronil SC sprays provided significant reductions in at least 4 wk. The percentage of ants marked with FB28 decreased significantly in both bait and spray treatments over 4 wk suggesting that the resurgence of ants in treated areas were because of immigration from untreated areas. It is likely that much larger areas will need to be treated to control Argentine ants in urban settings, especially if baits are being used.     

HIV-particles in spermatozoa of patients with AIDS and their transfer into the oocyte

By immunocytochemistry and in situ hybridization at the electron microscopy level, and by the PCR technique, we have shown that HIV-1 binds and enters normal sperm; that viral particles, their antigens, and nucleic acid are present in sperm from HIV-1 infected men; and that such sperm can transfer HIV-1 like particles to normal human oocytes. We also present evidence that a galactosylceramide-like compound is present on the sperm membrane and could function as an alternative receptor for HIV.     

Prospects for estimating nucleotide divergence with RAPDs

The technique of random amplification of polymorphic DNA (RAPD), which is simply polymerase chain reaction (PCR) amplification of genomic DNA by a single short oligonucleotide primer, produces complex patterns of anonymous polymorphic DNA fragments. The information provided by these banding patterns has proved to be of great utility for mapping and for verification of identity of bacterial strains. Here we consider whether the degree of similarity of the banding patterns can be used to estimate nucleotide diversity and nucleotide divergence. With haploid data, fragments generated by RAPD-PCR can be treated in a fashion very similar to that for restriction-fragment data. Amplification of diploid samples, on the other hand, requires consideration of the fact that presence of a band is dominant to absence of the band. After describing a method for estimating nucleotide divergence on the basis of diploid samples, we summarize the restrictions and criteria that must be met when RAPD data are used for estimating population genetic parameters.