A mechanism for maintaining an up-to-date GenBank(R)database via Usenet

In this paper, we describe an automated system for distributingupdates to the GenBank nucleic acid sequence database, usingthe Usenet news system as the underlying transport mechanism.Our system allows new loci to be distributed as soon as thesequences are available, over existing networks, using existingUsenet software and infrastructure currently available on awide range of computer systems.     

Partial purification and characterization of a human 3-methyladenine-DNA glycosylase.

A DNA glycosylase was purified about 30-fold from cultured human lymphoblasts (CCRF-CEM line) and was found to cleave 3-methyladenine from DNA alkylated with methyl methanesulfonate. The enzyme did not promote the release of 1-methyladenine, 7-methyladenine, or 7-methylguanine from DNA nor did it act on denatured methylated DNA. It produced apurinic sites in DNA alkylated with N-methyl-N-nitrosourea and ethyl methane-sulfonate as well as methyl methanesulfonate but not in untreated DNA or in DNA alkylated with nitrogen mustard or irradiated with ultraviolet light or X-rays. The glycosylase was free of detectable endonuclease activity in experiments with untreated DNA or DNA exposed to ultraviolet light; low levels of endonuclease activity, obtained when X-irradiated, alkylated, or depurinated DNA was the substrate, were attributed to contaminant apurinic endonuclease activity. This 3-methyladenine-DNA glycosylase has an estimated molecular weight of 34,000, is not dependent on divalent metal ions, and shows optimal activity at pH 7.5--8.5.     

Paint Deterioration as a Result of the Growth of Aureobasidium pullulans on Wood

Growth of Aureobasidium was noted on both painted and unpainted wood surfaces but not on painted glass slides, indicating that the source of carbon and energy for growth was not associated with paint components but was probably supplied by the wood. Several aromatic compounds related to aromatic extractives of wood were shown to support growth of this fungus.     

The embryonic rat parietal yolk sac. Changes in the morphology and composition of its basement membrane during development.

The basement membrane (Reichert's membrane) of the entire capsular portion of the parietal yolk sac of rat embryos was examined both morphologically and chemically at various stages of gestation. The overall microscopic and compositional analyses showed Reichert's membrane to be typical of basement membranes isolated from other tissues and species. However, with increasing gestational age (from 11.5 to 17.5 days) a number of changes involving Reichert's membrane were noted: 1. The thickness increased rapidly then declined, while the surface area increased tenfold; 2. The total protein content increased twenty-fold while the collagen content increased eight-fold. As a result, the relative collagen content declined significantly; 3. The changes in the amino acid and carbohydrate composition were consistent with the latter finding.The observations listed above were evaluated in light of their possible relevance to an understanding of the morphogenesis of basement membranes during development, and to the possible mechanisms involved in pathogenesis of basement membrane dysfunction.     

Presomal morphology and development of Prosthorhynchus formosus,Prosthenorchis elegans,and Moniliformis dubius (Acanthocephala)

Larvae removed at one-day intervals from laboratory infected intermediate hosts provided material for a comparative study of presomal development in Prosthorhynchus formosus (Van Cleave, '18) Travassos, '26, Prosthenorchis elegans (Diesing, 1851) Travassos, '15, and Moniliformis dubius Meyer, '33. Acanthellae begin development soon after entering intermediate hosts' hemocoels, and by the 18th day all three species possess three nuclear masses representing primordia of the proboscis, proboscis receptacle and ganglion, and trunk musculature and genitalia. Presomal development of P. formosus and P. elegans results in structures concurring with morphology of other adult palaeacanthocephalans and archiacanthocephalans. Development of M. dubius, however, differs from that of other archiacanthocephalans in that the muscular receptacle wall lines the entire surface of the nonmuscular sheath, failing to form a ventral cleft characteristic of other archiacanthocephalans. Unlike receptacle protrusor muscles of other archiacanthocephalan species, those of M. dubius spiral around the receptacle as they extend posteriad to attach individually to a pouchlike, muscular thickening at the receptacle's base. These protrusor muscles are distinct from the receptacle wall, as attested by their development alongside neck retractor muscles, not from the receptacle primordium, and the manner in which they are left to trail behind the receptacle when it is drawn anteriorly into the proboscis during larval development. The proboscis receptacle of M. dubius should not be thought of as being double-walled, as envisioned by previous workers.     

Life‐history constraints in grassland plant species: a growth‐defence trade‐off is the norm

Plant growth can be limited by resource acquisition and defence against consumers, leading to contrasting trade‐off possibilities. The competition‐defence hypothesis posits a trade‐off between competitive ability and defence against enemies (e.g. herbivores and pathogens). The growth‐defence hypothesis suggests that strong competitors for nutrients are also defended against enemies, at a cost to growth rate. We tested these hypotheses using observations of 706 plant populations of over 500 species before and following identical fertilisation and fencing treatments at 39 grassland sites worldwide. Strong positive covariance in species responses to both treatments provided support for a growth‐defence trade‐off: populations that increased with the removal of nutrient limitation (poor competitors) also increased following removal of consumers. This result held globally across 4 years within plant life‐history groups and within the majority of individual sites. Thus, a growth‐defence trade‐off appears to be the norm, and mechanisms maintaining grassland biodiversity may operate within this constraint.     

Perturbation of pulmonary immune functions by carbon nanotubes and susceptibility to microbial infection

Occupational and environmental pulmonary exposure to carbon nanotubes (CNT) is considered to be a health risk with a very low threshold of tolerance as determined by the United States Center for Disease Control. Immortalized airway epithelial cells exposed to CNTs show a diverse range of effects including reduced viability, impaired proliferation, and elevated reactive oxygen species generation. Additionally, CNTs inhibit internalization of targets in multiple macrophage cell lines. Mice and rats exposed to CNTs often develop pulmonary granulomas and fibrosis. Furthermore, CNTs have immunomodulatory properties in these animal models. CNTs themselves are proinflammatory and can exacerbate the allergic response. However, CNTs may also be immunosuppressive, both locally and systemically. Studies that examined the relationship of CNT exposure prior to pulmonary infection have reached different conclusions. In some cases, pre-exposure either had no effect or enhanced clearance of infections while other studies showed CNTs inhibited clearance. Interestingly, most studies exploring this relationship use pathogens which are not considered primary pulmonary pathogens. Moreover, harmony across studies is difficult as different types of CNTs have dissimilar biological effects. We used Pseudomonas aeruginosa as model pathogen to study how helical multi-walled carbon nanotubes (HCNTs) affected internalization and clearance of the pulmonary pathogen. The results showed that, although HCNTs can inhibit internalization through multiple processes, bacterial clearance was not altered, which was attributed to an enhanced inflammatory response caused by pre-exposure to HCNTs. We compare and contrast our findings in relation to other studies to gauge the modulation of pulmonary immune response by CNTs.