Distinction between mouse DNA polymerases alpha and beta by tryptic peptide mapping.

Results presented here and in a previous paper (Tanabe et al. (1979) Biochemistry 18, 3401--3406) indicate that mouse beta-polymerase is a single polypeptide with an apparent molecular weight of 40,000. This polypeptide has now been analyzed by tryptic peptide mapping. Comparison of the results with identical analysis of mouse alpha-polymerase reveals that the tryptic peptides derived from the two enzymes are different. These results indicate that beta-polymerase is neither a subunit of alpha-polymerase nor a proteolytic degradation product of alpha-polymerase.     

Defoliation-induced enhancement of total aboveground nitrogen yield of grasses

We conducted an experiment in a northern mixed-grass prairie at Wind Cave National Park, South Dakota, USA to evaluate the effect of defoliation frequency on aboveground net primary production (ANPP), shoot nitrogen concentration, and aboveground N yield of graminoids. ANPP was significantly reduced at weekly and biweekly defoliation frequencies, but unaffected relative to unclipped controls at monthly and bimonthly frequencies. By contrast, clipping at all frequencies increased shoot N concentration above that of controls, and this increase was greatest at monthly or more frequent defoliations. Total aboveground N yield and potential N yield to grazers were greatest at intermediate (bimonthly to biweekly) frequencies. We suggest that grazers may maximize their nutritional status in this system by periodically regrazing areas at frequencies near the approximately monthly optimum that we observed.     

Towards resolving and redefining Amphipyrinae (Lepidoptera,Noctuoidea, Noctuidae): a massively polyphyletic taxon

Amphipyrinae have long been a catchall taxon for Noctuidae, with most members lacking discernible morphological synapomorphies that would allow their assignment to one of the many readily diagnosable noctuid subfamilies. Here data from seven gene regions (> 5500 bp) for more than 120 noctuid genera are used to infer a phylogeny for Amphipyrinae and related subfamilies. Sequence data for 57 amphipyrine genera – most represented by the type species of the genus – are examined. We present here the first large‐scale molecular phylogenetic study of Amphipyrinae and the largest molecular phylogeny of Noctuidae to date; several proposed nomenclatural changes for well‐supported results; and the identification of areas of noctuid phylogeny where greater taxon sampling and/or genomic‐scale data are needed. Adult and larval morphology, along with life‐history traits, for taxonomic groupings most relevant to the results are discussed. Amphipyrinae are significantly redefined; many former amphipyrines, excluded as a result of these analyses, are reassigned to other noctuid subfamily‐level taxa. Four genera, Chamaeclea Grote, Heminocloa Barnes & Benjamin, Hemioslaria Barnes & Benjamin and Thurberiphaga Dyar, are transferred to the tribe Chamaecleini Keegan & Wagner tribe n. in Acontiinae. Stiriina is elevated to Stiriinae rev. stat. , Grotellina is elevated to Grotellinae rev. stat. and Annaphilina is elevated to Annaphilini rev. stat. Acopa Harvey is transferred to Bryophilinae, Aleptina Dyar is transferred to Condicinae, Leucocnemis Hampson and Oxycnemis gracillinea (Grote) are transferred to Oncocnemidinae, Nacopa Barnes & Benjamin is transferred to Noctuinae and Narthecophora Smith is transferred to Stiriinae. Azenia Grote (and its subtribe Azeniina), Cropia Walker, Metaponpneumata Möschler, Sexserrata Barnes & Benjamin and Tristyla Smith are transferred to Noctuidae incertae sedis. Hemigrotella Barnes & McDunnough (formerly in subtribe Grotellina) is retained in Amphipyrinae. Argentostiria Poole and Bistica Dyar are retained in Stiriini but removed from incertae sedis position. This published work has been registered on ZooBank: http://zoobank.org/urn:lsid:zoobank.org:pub:4A140782‐31BA‐445A‐B7BA‐6EAB98ED43FA .     

Use of Radiation Hybrid panels to map genetic loci

The mapping of genetic loci within organisms has been accelerated by the advent of Radiation Hybrid (RH) panels. These panels are available for humans and non-humans including mice, baboon, rat, and canine. This article contains a general protocol for the use of the Genebridge 4 whole genome RH panel to map a human locus. This protocol may also be adjusted to suit the other RH panels currently available.     

Climatic forcing and larval dispersal capabilities shape the replenishment of fishes and their habitat‐forming biota on a tropical coral reef

Fluctuations in marine populations often relate to the supply of recruits by oceanic currents. Variation in these currents is typically driven by large‐scale changes in climate, in particular ENSO (El Nino Southern Oscillation). The dependence on large‐scale climatic changes may, however, be modified by early life history traits of marine taxa. Based on eight years of annual surveys, along 150 km of coastline, we examined how ENSO influenced abundance of juvenile fish, coral spat, and canopy‐forming macroalgae. We then investigated what traits make populations of some fish families more reliant on the ENSO relationship than others. Abundance of juvenile fish and coral recruits was generally positively correlated with the Southern Oscillation Index (SOI), higher densities recorded during La Niña years, when the ENSO‐influenced Leeuwin Current is stronger and sea surface temperature higher. The relationship is typically positive and stronger among fish families with shorter pelagic larval durations and stronger swimming abilities. The relationship is also stronger at sites on the coral back reef, although the strongest of all relationships were among the lethrinids (r = .9), siganids (r = .9), and mullids (r = .8), which recruit to macroalgal meadows in the lagoon. ENSO effects on habitat seem to moderate SOI–juvenile abundance relationship. Macroalgal canopies are higher during La Niña years, providing more favorable habitat for juvenile fish and strengthening the SOI effect on juvenile abundance. Conversely, loss of coral following a La Niña‐related heat wave may have compromised postsettlement survival of coral dependent species, weakening the influence of SOI on their abundance. This assessment of ENSO effects on tropical fish and habitat‐forming biota and how it is mediated by functional ecology improves our ability to predict and manage changes in the replenishment of marine populations.     

Plant–animal interactions between carnivorous plants,sheet‐web spiders,and ground‐running spiders as guild predators in a wet meadow community

1. Plant–animal interactions are diverse and widespread shaping ecology, evolution, and biodiversity of most ecological communities. Carnivorous plants are unusual in that they can be simultaneously engaged with animals in multiple mutualistic and antagonistic interactions including reversed plant–animal interactions where they are the predator. Competition with animals is a potential antagonistic plant–animal interaction unique to carnivorous plants when they and animal predators consume the same prey.
2. The goal of this field study was to test the hypothesis that under natural conditions, sundews and spiders are predators consuming the same prey thus creating an environment where interkingdom competition can occur.
3. Over 12 months, we collected data on 15 dates in the only protected Highland Rim Wet Meadow Ecosystem in Kentucky where sundews, sheet‐web spiders, and ground‐running spiders co‐exist. One each sampling day, we attempted to locate fifteen sites with: (a) both sheet‐web spiders and sundews; (b) sundews only; and (c) where neither occurred. Sticky traps were set at each of these sites to determine prey (springtails) activity–density. Ground‐running spiders were collected on sampling days. DNA extraction was performed on all spiders to determine which individuals had eaten springtails and comparing this to the density of sundews where the spiders were captured.
4. Sundews and spiders consumed springtails. Springtail activity–densities were lower, the higher the density of sundews. Both sheet‐web and ground‐running spiders were found less often where sundew densities were high. Sheet‐web size was smaller where sundew densities were high.
5. The results of this study suggest that asymmetrical exploitative competition occurs between sundews and spiders. Sundews appear to have a greater negative impact on spiders, where spiders probably have little impact on sundews. In this example of interkingdom competition where the asymmetry should be most extreme, amensalism where one competitor experiences no cost of interaction may be occurring.

     

HYLAS: program for generating H curves (abstract three-dimensional representations of long DNA sequences)

The computer program HYLAS generates from a standard DNA lettersequence a three-dimensional space curve (H curve) which embodiesthe entire information content of the original nucleotide sequence.The program can display H curves either as two-dimensional (frontand side view) projections or as stereo-pair images. The curvescan be marked at specific nucleotide locations, annotated, rotatedfor observation from any viewing angle, and manipulated forconvenient side-by-side comparisons. Unlike the cumbersome lettersequences, H curves can be drastically condensed in size withoutlosing their ability to reflect the global nucleotide-distributionpattern of the entire DNA sequence. Often, biologically importantloci can be visually identified on the H curves. HYLAS is writtenin FORTRAN with separate mainframe (IBM- VM/CMS) and microcomputer(MS-DOS) versions. It uses the Tektronix-TCS library of graphicsubroutines. Received on October 24, 1988; accepted on July 15, 1989