Order of the aro-6 and cpl-1 loci on linkage group VI of Neurospora

The results reported here locate the cpl-1 locus 5.5 centimorgans to the left of the aro-6 locus on linkage group VIL of Neurospora

Chromosome walking and gene cloning using a Neurospora crassa Linkage Group VI-specific library.

Chromosome walks from the cpc-1 and Bml loci were extended and the cys-2 locus cloned by sib-selection using a subset of the Orbach/Sachs Neurospora crassa genomic library

Identification of a cosmid clone containing the Neurospora crassa lys-5 and un-4 genes, isolation of a partial lys-5 cDNA and associated chromosome walking.

The un-4 gene of Neurospora crassa was cloned to determine the limits of a chromosome walk on linkage group VI (LGVI) and to allow analysis of un loci on LGVI. Subsequent analysis identified the lys-5 locus on the same cosmid clone as un-4. We have isolated and sequenced a partial lys-5 cDNA clone and initiated a chromosome walk from the lys-5, un-4 cosmid clone

Characterization of Neurospora crassa albino mutants that were previously unassigned to locus

Neurospora crassa mutant hunts by various groups have identified albino (al) mutants that map to the al-1 - al-2 region on the right arm of linkage group I. The cloning of the al-1 and al-2 genes (Schmidhauser et al. 1990 Mol. Cell. Biol. 10:5064-5070, Schmidhauser et al. 1994 J. Biol. Chem. 269:12060-12066) allows assignment of locus to the above mutants by DNA mediated transformation. Analysis of phytoene desaturases from different organisms indicates at least three types of enzymes as defined by the number of desaturation steps carried out (Sandmann 1994 J. Plant Physiol. 143:444-447). The N. crassa phytoene desaturase, the al-1 gene product, introduces four double bonds converting phytoene to lycopene. Of the three intermediates in this reaction sequence two are colored. The occurrence of visibly distinguishable albino alleles in N. crassa has been noted (Perkins 1989 Fungal Genetics Newsl. 36:63). Assignment of locus to N. crassaalbino alleles represents a first step in the functional characterization of N. crassa carotenogenic loci

A Protocol Guide for the N. crassa Yeast Artificial Chromosome Library

A yeast artificial chromosome (YAC) library of Neurospora crassa strain 74-OR23-1A has been constructed. This library has been used to clone 750 kb of contiguous DNA sequences from the centromere region of linkage group VII (M. Centola and J. Carbon. 1994. Mol. Cell. Biol. 14:1510-1519). The purpose of this article is explicitly to outline procedures that have been developed for library screening and chromosome walking

Effects of relative humidity on aerosol light scattering in the Arctic

Aerosol particles experience hygroscopic growth in the ambient atmosphere. Their optical properties – especially the aerosol light scattering – are therefore strongly dependent on the ambient relative humidity (RH). In-situ light scattering measurements of long-term observations are usually performed under dry conditions (RH>30–40%). The knowledge of this RH effect is of eminent importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. This study combines measurements and model calculations to describe the RH effect on aerosol light scattering for the first time for aerosol particles present in summer and fall in the high Arctic. For this purpose, a field campaign was carried out from July to October 2008 at the Zeppelin station in Ny-Ålesund, Svalbard. The aerosol light scattering coefficient σ<sub>sp</sub>(λ) was measured at three distinct wavelengths (λ=450, 550, and 700 nm) at dry and at various, predefined RH conditions between 20% and 95% with a recently developed humidified nephelometer (WetNeph) and with a second nephelometer measuring at dry conditions with an average RH<10% (DryNeph). In addition, the aerosol size distribution and the aerosol absorption coefficient were measured. The scattering enhancement factor <i>f</i>(RH, λ) is the key parameter to describe the RH effect on σ<sub>sp</sub>(λ) and is defined as the RH dependent σ<sub>sp</sub>(RH, λ) divided by the corresponding dry σ<sub>sp</sub>(RH<sub>dry</sub>, λ). During our campaign the average <i>f</i>(RH=85%, λ=550 nm) was 3.24±0.63 (mean ± standard deviation), and no clear wavelength dependence of <i>f</i>(RH, λ) was observed. This means that the ambient scattering coefficients at RH=85% were on average about three times higher than the dry measured in-situ scattering coefficients. The RH dependency of the recorded <i>f</i>(RH, λ) can be well described by an empirical one-parameter equation. We used a simplified method to retrieve an apparent hygroscopic growth factor <i>g</i>(RH), defined as the aerosol particle diameter at a certain RH divided by the dry diameter, using the WetNeph, the DryNeph, the aerosol size distribution measurements and Mie theory. With this approach we found, on average, <i>g</i>(RH=85%) values to be 1.61±0.12 (mean±standard deviation). No clear seasonal shift of <i>f</i>(RH, λ) was observed during the 3-month period, while aerosol properties (size and chemical composition) clearly changed with time. While the beginning of the campaign was mainly characterized by smaller and less hygroscopic particles, the end was dominated by larger and more hygroscopic particles. This suggests that compensating effects of hygroscopicity and size determined the temporal stability of <i>f</i>(RH, λ). During sea salt influenced periods, distinct deliquescence transitions were observed. At the end we present a method on how to transfer the dry in-situ measured aerosol scattering coefficients to ambient values for the aerosol measured during summer and fall at this location

One-Liners

One liners from: N.M. Martinez-Rossi, C. Andrade-Monteiro and S.R.C. Pombeiro; M. Orbach ; H. Liu and TJ. Schmidhauser; P.A. Hubbard and C.H. Wilso