Modelling ultraviolet exposures in a school environment.

A technique has been developed to represent erythemally effective ultraviolet radiation exposure within a school environment. The technique models the erythemally effective exposure onto a horizontal plane representation of a mapped school environment located in Hervey Bay (25 degrees S, 153 degrees E), Australia. The input parameters used to model the ultraviolet exposures received within the school playground included the measured sky view, ground albedo and standing surface albedo. Estimates of the erythemally effective ultraviolet exposure received within the school playground during morning tea and lunch time meal breaks during a winter and summer school day are presented. The influence of tree shade and building structure was found to vary significantly with solar zenith angle modelled over the winter and summer school meal break times with horizontal plane exposures predicted to vary from between 0 and 7 SED at different locations within the playground. The technique presented provides a method that can be followed to examine the effect of surrounding buildings and surface structures of real environments on the predicted horizontal plane ultraviolet exposure.     

Intrinsic potential for high fetal hemoglobin production in a Druze family with β-thalassemia is due to an unlinked genetic determinant

Summary The mechanism for elevated production of fetal hemoglobin (Hb F) in a Druze patient with °-thalassemia intermedia was investigated. Heterozygous family members exhibited normal Hb F levels, suggesting that the increase in -gene expression in the propositus may be partly due to anemic stress. Erythroid progenitors of these family members cultured in vitro [burst forming units (erythroid); (BFUe)] showed elevated synthesis of Hb F, indicating the existence of a genetically determined intrinsic capacity for high Hb F production in this family. The propositus was found to be homozygous for a IVS2-position 1 mutation, on the background of Mediterranean haplotype I, which is not known to be linked to high Hb F production. Moreover, extensive molecular studies of the -globin gene cluster, including sequence analysis of the promoter regions of the -globin genes, did not reveal any cisacting mechanism that could account for the high Hb F production in the propositus. A young niece of the propositus with °-thalassemia major was recently discovered, who was homozygous for the same -globin allele and haplotype as the propositus. However, unlike her uncle, she does not have a high Hb F level and presents with a severe clinical course. Her inability to produce high Hb F suggests that the genetic determinant for increased -gene expression in the propositus is unlinked to the -globin gene cluster.     

Quaternary structure,Mg2+ interactions,and some kinetic properties of the (β-galactosidase fromThermoanaerobacterium thermosulfurigenes EM1

Theβ-galactosidase fromThermoanaerobacterium thermosulfurigenes EM1 was found to be a dimer with a monomer molecular weight of about 85,000. It lacks theα-peptide and an importantα-helix that are both needed for dimer-dimer interaction and there is no homology in other important dimer-dimer interaction areas. These differences in structure probably account for the dimeric (rather than tetrameric) structure. Only 0.19 Mg²⁺ bound per monomer and Mg²⁺ had only small effects on the activity and heat stability. The absence of residues equivalent to Glu-416 and His-418 (two of the three ligands to Mg²⁺ in theβ-galactosidase fromEscherichia coli) probably accounts for the low level of Mg²⁺ binding and the consequent lack of response to Mg²⁺. Both Na⁺ and K⁺ also had no effect on the activity. The enzyme activity witho-nitrophenyl-β-D-galactopyanoside (ONPG) was very similar to that withp-nitrophenyl-β-D-β-D-galactopyranoside (PNPG) and the ONPG pH profile was very similar to the PNPG pH profile. These differences are in contrast to theE. coli β-galactosidase, which dramatically discriminates between these two substrates. The lack of discrimination by theT. thermosulfurigenes β-galactosidase could be due to the absence of the sequence equivalent to residues 910-1023 of theE. coli β-galactosidase. Trp-999 is probably of the most importance. Trp-999 of theE. coli β-galactosidase is important for aglycone binding and ONPG and PNPG differ only in their aglycones. The suggestion that the aglycone site of theT. thermosulfurigenes β-galactosidase is different was strengthened by competitive inhibition studies. Compared toE. coli β-galactosidase, D-galactonolactone was a very good inhibitor of theT. thermosulfurigenes enzyme, while L-ribose inhibited poorly. These are transition-state analogs and the results indicate thatT. thermosulfurigenes β-galactosidase binds the transition state differently than doesE. coli β-galactosidase. Methanol and glucose were good acceptors of galactose, and allolactose was formed when glucose was the acceptor. Allolactose could not, however, be detected by TLC when lactose was the substrate. The differences noted may be due to the thermophilic nature ofT. thermosulfurigenes.     

Choice of function for mortality analysis: Effective forecasting depends on a minimum parameter representation

For nearly two centuries actuaries, statisticians and demographers have sought a parameter space in which the mortality pattern of a population could be located, that would be linked to the larger space of age-specific rates by an analytical formula. Gompertz, Makeham, Brillinger, Wolfenden, Pollard and others have made contributions to this end. Model or reference tables perform a similar task, usually with fewer parameters, but are less easily manipulated. A common means of reducing dimensionality is to map the original space of mortality rates in five-year groups on a straight line in which are located the expectations of life at age zero (ė₀). A small-space representation is advantageous for filling gaps in data. If the only fact known about a country is the fraction of girls who have a living mother, then a one-dimensional set can be indexed on this to provide the full detail of mortality, assuming the unknown mortality is part of that set. For forecasting one would like the succession of life tables for a given population over past times to be representable by points moving in a simple way through a parameter space—ideally in a straight line—over a succession of calendar years. The simpler the curve, the more realistic is likely to be its projection into the future. The Brass relational method provides a trajectory well suited to extrapolation in a space of only two parameters. Some useful extensions of this have recently been devised.     

Lysosomal pool of free-amino acids

Free (non-protein) amino acids were measured in whole rat liver and in unmodified lysosomes which were prepared from rat liver by the technique of free-flow electrophoresis. Significant intralysosomal pools of threonine, serine, valine, cystine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine and arginine were found. No efflux occurred from rat liver lysosomes in isotonic buffered sucrose at 0°C, but all amino acids showed various degrees of efflux at 20⁰ and 37⁰.     

The comparison of rat liver rough endoplasmic reticulum membrane proteins before and after in vitro removal of its bound ribosomes

The comparison of the proteins of rat liver rough membrane after stripping with EDTA or KCl-puromycin by two dimensional gel electrophoresis is described. By stripping the membrane with EDTA, most of the basic ribosomal proteins are still attached to the membrane; in contrast to the EDTA stripping method, treatment with KCl-puromycin removes most of the ribosomal proteins and does not remove any of the membranal proteins.     

Moths complement bumblebee pollination of red clover: a case for day-and-night insect surveillance

Recent decades have seen a surge in awareness about insect pollinator declines. Social bees receive the most attention, but most flower-visiting species are lesser known, non-bee insects. Nocturnal flower visitors, e.g. moths, are especially difficult to observe and largely ignored in pollination studies. Clearly, achieving balanced monitoring of all pollinator taxa represents a major scientific challenge. Here, we use time-lapse cameras for season-wide, day-and-night pollinator surveillance of Trifolium pratense (L.; red clover) in an alpine grassland. We reveal the first evidence to suggest that moths, mainly Noctua pronuba (L.; large yellow underwing), pollinate this important wildflower and forage crop, providing 34% of visits (bumblebees: 61%). This is a remarkable finding; moths have received no recognition throughout a century of T. pratense pollinator research. We conclude that despite a non-negligible frequency and duration of nocturnal flower visits, nocturnal pollinators of T. pratense have been systematically overlooked. We further show how the relationship between visitation and seed set may only become clear after accounting for moth visits. As such, population trends in moths, as well as bees, could profoundly affect T. pratense seed yield. Ultimately, camera surveillance gives fair representation to non-bee pollinators and lays a foundation for automated monitoring of species interactions in future.