An extraordinary new genus and species of spider wasps (Insecta: Hymenoptera: Pompilidae) from Southeast Asia

The new genus Aberropompilus Shimizu & Wahis, family Pompilidae, is described from Southeast Asia (Malaysia, Thailand) based on the new species A. dayi Shimizu & Wahis. Its peculiar morphological characteristics and taxonomic position within the family are discussed and the genus is tentatively placed in the subfamily Pepsinae.     

A genetic basis for Pseudomonas aeruginosa biofilm antibiotic resistance

Biofilms are surface-attached microbial communities with characteristic architecture and phenotypic and biochemical properties distinct from their free-swimming, planktonic counterparts. One of the best-known of these biofilm-specific properties is the development of antibiotic resistance that can be up to 1,000-fold greater than planktonic cells. We report a genetic determinant of this high-level resistance in the Gram-negative opportunistic pathogen, Pseudomonas aeruginosa. We have identified a mutant of P. aeruginosa that, while still capable of forming biofilms with the characteristic P. aeruginosa architecture, does not develop high-level biofilm-specific resistance to three different classes of antibiotics. The locus identified in our screen, ndvB, is required for the synthesis of periplasmic glucans. Our discovery that these periplasmic glucans interact physically with tobramycin suggests that these glucose polymers may prevent antibiotics from reaching their sites of action by sequestering these antimicrobial agents in the periplasm. Our results indicate that biofilms themselves are not simply a diffusion barrier to these antibiotics, but rather that bacteria within these microbial communities employ distinct mechanisms to resist the action of antimicrobial agents.     

Unprecedented Arctic ozone loss in 2011

Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded.     

Ubiquitous occurrence of 2-nitrofluoranthene and 2-nitropyrene in air

Several nitrated polycyclic aromatic hydrocarbons (nitro-PAH) are direct-acting mutagens and/or carcinogens, and are important constituents of combustion emissions and ambient air. These nitro-PAH are emitted from various combustion sources including gasoline and diesel engine exhaust, aluminium smelting effluent, coal fly ash, wood smoke, and cigarette smoke condensates. Of these, diesel engine exhaust is the best characterized, more than 50 nitrated polycyclic aromatic compounds having been identified by Paputa-Peck et al., including 1-nitropyrene (1-NP) as the single most abundant nitro-PAH. However, nitro-PAH may also be formed during source-receptor transport by atmospheric reactions of adsorbed or gas-phase PAH with oxides of nitrogen, nitric acid and other atmospherically important species such as the OH radical. Evidence for the atmospheric formation of nitro-PAH has come only recently, from observations that 2-nitropyrene (2-NP) and 2-nitrofluoranthene (2-NF) neither of which has been reported to be emitted from combustion sources, are among the major nitro-PAH present in ambient air. We present here data from several locations which demonstrate that these two atmospherically formed nitro-PAH are ubiquitous in tropospheric ambient air.     

Preliminary assessment of velvet ant (Hymenoptera: Mutillidae) diversity in the deserts of southern California

The deserts of southern California house a diverse and unique insect fauna. Velvet ants (Hymenoptera: Mutillidae) are common in these deserts. Velvet ants are important to ecosystem health, particularly in desert environments, because they are parasitic on the bees and wasps that help maintain overall ecosystem function. The goal of this study was to measure velvet ant diversity across the deserts of southern California. We made preliminary collections from 10 sites in a variety of areas in the western Sonoran Desert (Colorado Desert), the Mojave Desert, and the Great Basin Desert. We measured β-diversity using Sørensen’s similarity index to compare velvet ant richness and relative abundance between different sites. To determine how accurate our similarity estimates were, and to gain an understanding of actual velvet ant diversity, we also compared velvet ant richness of 2 sites (Algodones Sand Dunes and Deep Canyon) using data obtained from the examination of museum specimens borrowed from over 12 museums across the West. Comparisons of velvet ant faunas between sites revealed low similarities (0.167–0.75 species richness only; 0.022–0.67 both abundance and richness). Low similarity values indicate that a rich velvet ant fauna exists in the deserts of southern California.     

Identification of an altered splice site in Ashkenazi Tay-Sachs disease

Tay-Sachs disease is an autosomal recessive genetic disorder resulting from mutation of the HEXA gene encoding the alpha-subunit of the lysosomal enzyme, beta-N-acetylhexosaminidase A (ref. 1). A relatively high frequency of carriers (1/27) of a lethal, infantile form of the disease is found in the Ashkenazi Jewish population, but it is not yet evident whether this has resulted from a founder effect and random genetic drift or from a selective advantage of heterozygotes. We have identified a single-base mutation in a cloned fragment of the HEXA gene from an Ashkenazi Jewish patient. This change, the substitution of a C for G in the first nucleotide of intron 12 is expected to result in defective splicing of the messenger RNA. A test for the mutant allele based on amplification of DNA by the 'polymerase chain rection and cleavage of a DdeI restriction site generated by the mutation revealed that this case and two other cases of the Ashkenazi, infantile form of Tay-Sachs disease are heterozygous for two different mutations. The occurrence of multiple mutant alleles warrants further examination of the selective advantage hypothesis.