Involvement of human mucous saliva and salivary mucins in the aggregation of the oral bacteria Streptococcus sanguis,Streptococcus oralis,and Streptococcus rattus

The contribution of human parotid (Par) and submandibular/sublingual (SM/SL) saliva and of the human whole salivary mucin fraction (HWSM) to saliva-induced bacterial aggregation was studied for S. sanguis C476, S. oralis I581, and S. rattus HG 59. The mucous SM/SL saliva showed a much higher aggregation potency towards the S. sanguis and S. oralis strain than did the serous Par saliva. The SM/SL saliva-induced aggregation was observed after 30 min, at 60 min followed by the Par saliva-induced aggregation, and showed a 4-fold higher aggregation titer of 128 for S. sanguis, and an 8-fold higher titer of 516 for S. oralis. In contrast, the Par saliva showed a slightly higher aggregation activity than the SM/SL saliva towards S. rattus as judged by a twofold higher titer of 64. Morphologically, however, the SM/SL saliva-induced aggregation of S. rattus was far more pronounced as was also found for S. sanguis. Finally, the HWSM-induced aggregation showed a 4 to 8-fold higher titer than the originating salivary source, measuring 2048 for S. oralis and 128 for S. rattus. Moreover, no difference was observed in aggregation activity between the HWSM from whole saliva of a blood group O donor and the HWSM from SM/SL saliva of a blood group A donor. All the data point to an important, though not exclusive role of the human salivary mucin fraction in the saliva-induced aggregation of these strains.     

Primate evolution at the DNA level and a classification of hominoids

Summary The genetic distances among primate lineages estimated from orthologous noncoding nucleotide sequences of -type globin loci and their flanking and intergenic DNA agree closely with the distances (delta T₅₀H values) estimated by cross hybridization of total genomic single-copy DNAs. These DNA distances and the maximum parsimony tree constructed for the nucleotide sequence orthologues depict a branching pattern of primate lineages that is essentially congruent with the picture from phylogenetic analyses of morphological characters. The molecular evidence, however, resolves ambiguities in the morphological picture and provides an objective view of the cladistic position of humans among the primates. The molecular data group humans with chimpanzees in subtribe Hominina, with gorillas in tribe Hominini, orangutans in subfamily Homininae, gibbons in family Hominidae, Old World monkeys in infraorder Catarrhini, New World monkeys in semisuborder Anthropoidea, tarsiers in suborder Haplorhini, and strepsirhines (lemuriforms and lorisiforms) in order Primates. A seeming incongruency between organismal and molecular levels of evolution, namely that morphological evolution appears to have speeded up in higher primates, especially in the lineage to humans, while molecular evolution has slowed down, may have the trivial explanation that relatively small genetic changes may sometimes result in marked phenotypic changes.     

A model of fracture testing of soft viscoelastic tissues

Fracture, or tear, toughness of soft tissues can be computed from the work of fracture divided by the area of new crack surface. For soft tissues without significant plastic deformation, total work, which can be measured experimentally, is composed of the sum of fracture and viscoelastic work. In order to deduce fracture work, a method is needed to estimate viscoelastic work.Two different methods (Ph.D. Dissertation, University of Minnesota, 2000; J. Mater. Sci.: Mater. Med. 12 (2001) 327) have been proposed to estimate viscoelastic work in a fracture test of a soft tissue. The relative merits of these methods are unknown because the true viscoelastic work in an experiment is unknown. In order to characterize the accuracy of these methods, a theoretical model of crack propagation of viscoelastic soft tissue in a tensile test is presented, from which the exact viscoelastic work is calculated. The material is assumed to obey the standard linear solid model.The "exact" solution for the viscoelastic work during the fracture is computed from the model and compared with the work estimated by the two methods. It was found that both methods tend to underestimate the viscoelastic work done, and thus overestimate the fracture work and fracture toughness, although the errors were greater with the Fedewa method. It was further found that low displacement rates can give rise to a "snap" effect, where rapid crack growth can cause a disproportionate amount of viscoelastic energy to be dissipated during unloading. This modeling approach may be useful in evaluating other experimental methods of soft tissue fracture.     

Isolation of a ubiquitin-like (UBL5) gene from a screen identifying highly expressed and conserved iris genes

We have screened a human adult iris cDNA library to identify genes that are highly expressed and conserved between humans and pigs. We identified human iris cDNAs that hybridized at high stringency to a porcine choroidal ring cDNA probe. Of 1568 human iris cDNAs examined, 176 were found to have high expression in porcine choroidal rings. One of the 176 clones was identified as a previously uncharacterized cDNA that we have named the Ubiquitin-like 5 gene (UBL5). The UBL5 gene is located on chromosome 19p13.2, and its genomic structure has been examined. There is a UBL5 pseudogene on chromosome 17p11.2. We have also found homologues to the UBL5 gene in Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae. Northern blot analysis of the Ubiquitin-like gene 5 revealed expression in every tissue tested, with the highest levels of RNA expression in heart, skeletal muscle, kidney, liver, iris, and lymphoblasts. Intracellular localization experiments in COS-7 cells showed that the recombinant UBL5 protein is cytoplasmic. Western analysis demonstrated that the recombinant UBL5 protein is approximately 9 kDa, as predicted from the cDNA. A comparison between UBL5 and its homologues with other Ubiquitin-like proteins and Ubiquitin, using the PROTDIST program, suggests that the UBL5 genes are a separate class of Ubiquitin-like genes. Further characterization of the UBL5 gene will determine the function of the encoded protein and whether it is a candidate for ocular disease.     

Multi-attribute ecological river typology for assessing ecological condition and conservation planning

A river classification framework is needed to make good management and planning decisions about river health and biodiversity. We developed a multi-attribute ecological river typology to address this need in the Australian State of New South Wales (801,428 km²). Multivariate patterns in data collected from 322 reference sites were used to define river types for each attribute: abiotic features (10 types), fish assemblages (6 types) and macroinvertebrate assemblages from river edges (8 types) and riffle zones (5 types). We used classification tree analysis to define broad regions for each attribute and then to construct identification keys for river types within each region using slope, elevation, maximum distance from source, latitude and mean annual rainfall. These keys allow the mapping of the likely spatial extent of river types and the assignment of a multi-attribute river-type identity to a river reach anywhere in the State. We used the average dissimilarity distances among the river types and the rates of misclassification of reference sites to assess the reliability of the assignments for different attributes in different regions. This approach to river classification can be applied anywhere in the world, resulting in simple to highly complex typologies depending on data availability. In data-poor areas it may result in a single attribute typology based on remotely derived variables and a coarsely defined reference condition. In data-rich areas the typology may have a large number of attributes using very large datasets with high resolution. Handling editor: D. Dudgeon     

Sequence analysis and organization of the Neodiprion abietis nucleopolyhedrovirus genome

Of 30 baculovirus genomes that have been sequenced to date, the only nonlepidopteran baculoviruses include the dipteran Culex nigripalpus nucleopolyhedrovirus and two hymenopteran nucleopolyhedroviruses that infect the sawflies Neodiprion lecontei (NeleNPV) and Neodiprion sertifer (NeseNPV). This study provides a complete sequence and genome analysis of the nucleopolyhedrovirus that infects the balsam fir sawfly Neodiprion abietis (Hymenoptera, Symphyta, Diprionidae). The N. abietis nucleopolyhedrovirus (NeabNPV) is 84,264 bp in size, with a G+C content of 33.5%, and contains 93 predicted open reading frames (ORFs). Eleven predicted ORFs are unique to this baculovirus, 10 ORFs have a putative sequence homologue in the NeleNPV genome but not the NeseNPV genome, and 1 ORF (neab53) has a putative sequence homologue in the NeseNPV genome but not the NeleNPV genome. Specific repeat sequences are coincident with major genome rearrangements that distinguish NeabNPV and NeleNPV. Genes associated with these repeat regions encode a common amino acid motif, suggesting that they are a family of repeated contiguous gene clusters. Lepidopteran baculoviruses, similarly, have a family of repeated genes called the bro gene family. However, there is no significant sequence similarity between the NeabNPV and bro genes. Homologues of early-expressed genes such as ie-1 and lef-3 were absent in NeabNPV, as they are in the previously sequenced hymenopteran baculoviruses. Analyses of ORF upstream sequences identified potential temporally distinct genes on the basis of putative promoter elements.