Pathogenesis of adenovirus type 5 pneumonia in cotton rats (Sigmodon hispidus).

Cotton rats (Sigmodon hispidus) were inoculated intranasally with 10(2.0) to 10(10.0) PFU of human adenovirus type 5. The virus replicated to a high titer in pulmonary tissues, with the peak titer being proportional to the input dose. The 50% lethal dose was 10(9.4) PFU. Histopathologic changes were proportional to the infecting inoculum and included the infiltration of interstitial and intra-alveolar areas, moderate damage to bronchiolar epithelium, and cellular infiltration of peribronchiolar and perivascular regions. These changes could be divided into two phases: an early phase (affecting alveoli, bronchiolar epithelium, and peribronchiolar regions) with an infiltrate consisting primarily of monocytes-macrophages and neutrophils, with occasional lymphocytes, and a later phase (affecting peribronchiolar and perivascular regions) with an infiltrate consisting almost exclusively of lymphocytes. In both phases, the predominant process was the response of the host to infection, rather than direct viral damage to infected cells. An infecting inoculum of 10(8.0) PFU or larger caused severe damage to type II alveolar cells, which were swollen, showed a loss of lamellar bodies, and were surrounded by polymorphonuclear leukocytes and macrophages. No evidence of complete viral replication was found in type II alveolar cells.     

Bovine respiratory syncytial virus protects cotton rats against human respiratory syncytial virus infection.

Human respiratory syncytial virus (HRSV) is the most frequent cause of severe respiratory infections in infancy. No vaccine against this virus has yet been protective, and antiviral drugs have been of limited utility. Using the cotton rat model of HRSV infection, we examined bovine respiratory syncytial virus (BRSV), a cause of acute respiratory disease in young cattle, as a possible vaccine candidate to protect children against HRSV infection. Cotton rats were primed intranasally with graded doses of BRSV/375 or HRSV/Long or were left unprimed. Three weeks later, they were challenged intranasally with either BRSV/375, HRSV/Long (subgroup A), or HRSV/18537 (subgroup B). At intervals postchallenge, animals were sacrificed for virus titration and histologic evaluation. Serum neutralizing antibody titers were determined at the time of viral challenge. BRSV/375 replicated to low titers in nasal tissues and lungs. Priming with 10(5) PFU of BRSV/375 effected a 500- to 1,000-fold reduction in peak nasal HRSV titer and a greater than 1,000-fold reduction in peak pulmonary HRSV titer upon challenge with HRSV/Long or HRSV/18537. In contrast to priming with HRSV, priming with BRSV did not induce substantial levels of neutralizing antibody against HRSV and was associated with a delayed onset of clearance of HRSV upon challenge. Priming with BRSV/375 caused mild nasal and pulmonary pathology and did not cause exacerbation of disease upon challenge with HRSV/Long. Our findings suggest that BRSV may be a potential vaccine against HRSV and a useful tool for studying the mechanisms of immunity to HRSV.     

New high-toxicity mosquitocidal strains of Bacillus sphaericus lacking a 100-kilodalton-toxin gene.

Five new high-toxicity mosquitocidal strains of Bacillus sphaericus were isolated in Singapore. They all belong to phage group 8 and have binary toxin (51.4- plus 41.9-kDa) genes located on the chromosome but lack a 100-kDa-toxin gene. These strains of B. sphaericus constitute a new subgroup, as only two weakly toxic strains in phage group 8 have previously been described and all the known high-toxicity strains have both binary toxin and 100-kDa-toxin genes.     

Recovery of the coral Montastrea annularis in the Florida Keys after the 1987 Caribbean “bleaching event”

Many reef-building corals and other cnidarians lost photosynthetic pigments and symbiotic algae (zooxanthellae) during the coral bleaching event in the Caribbean in 1987. The Florida Reef Tract included some of the first documented cases, with widespread bleaching of the massive coral Montastrea annularis beginning in late August. Phototransects at Carysfort Reef showed discoloration of >90% of colonies of this species in March 1988 compared to 0% in July 1986; however no mortality was observed between 1986 and 1988. Samples of corals collected in February and June 1988 had zooxanthellae densities ranging from 0.1 in the most lightly colored corals, to 1.6x10⁶ cells/cm² in the darker corals. Minimum densities increased to 0.5x10⁶ cells/cm² by August 1989. Chlorophyll-a content of zooxanthellae and zooxanthellar mitotic indices were significantly higher in corals with lower densities of zooxanthellae, suggesting that zooxanthellar at low densities may be more nutrientsufficient than those in unbleached corals. Ash-free dry weight of coral tissue was positively correlated with zooxanthellae density at all sample times and was significantly lower in June 1988 compared to August 1989. Proteins and lipids per cm² were significantly higher in August 1989 than in February or June, 1988. Although recovery of zooxanthellae density and coral pigmentation to normal levels may occur in less than one year, regrowth of tissue biomass and energy stores lost during the period of low symbiont densities may take significantly longer.     

A differential proteomics study of cerebrospinal fluid from individuals with Niemann-Pick disease,Type C1

Niemann-Pick, type C1 (NPC1) is a fatal, neurodegenerative disease, which belongs to the family of lysosomal diseases. In NPC1, endo/lysosomal accumulation of unesterified cholesterol and sphingolipids arise from improper intracellular trafficking resulting in multi-organ dysfunction. With the proximity between the brain and cerebrospinal fluid (CSF), performing differential proteomics provides a means to shed light to changes occurring in the brain. In this study, CSF samples obtained from NPC1 individuals and unaffected controls were used for protein biomarker identification. A subset of these individuals with NPC1 are being treated with miglustat, a glycosphingolipid synthesis inhibitor. Of the 300 identified proteins, 71 proteins were altered in individuals with NPC1 compared to controls including cathepsin D, and members of the complement family. Included are a report of 10 potential markers for monitoring therapeutic treatment. We observed that pro-neuropeptide Y (NPY) was significantly increased in NPC1 individuals relative to healthy controls; however, individuals treated with miglustat displayed levels comparable to healthy controls. In further investigation, NPY levels in a NPC1 mouse model corroborated our findings. We posit that NPY could be a potential therapeutic target for NPC1 due to its multiple roles in the central nervous system such as attenuating neuroinflammation and reducing excitotoxicity.     

Mutational analysis of U1 function in Schizosaccharomyces pombe: pre-mRNAs differ in the extent and nature of their requirements for this snRNA in vivo.

The U1 snRNP is known to play a critical role in spliceosome assembly, at least in part through base pairing of its RNA moiety to the substrate, but many details remain to be elucidated. To further dissect U1 snRNA function, we have analyzed 14 single point mutations in the six nucleotides complementary to the 5' splice site for their effects on growth and splicing in the fission yeast Schizosaccharomyces pombe. Three of the four alleles previously found to support growth of Saccharomyces cerevisiae are lethal in S. pombe, implying a more critical role for the 5' end of U1 in fission yeast. Furthermore, a comparison of phenotypes for individual nucleotide substitutions suggests that the two yeasts use different strategies to modulate the extent of pairing between U1 and the 5' splice site. The importance of U1 function in S. pombe is further underscored by the lethality of several single point mutants not examined previously in S. cerevisiae. In total, only three alleles complement the U1 gene disruption, and these strains are temperature-sensitive for growth. Each viable mutant was tested for impaired splicing of three different S. pombe introns. Among these, only the second intron of the cdc2 gene (cdc2-I2) showed dramatic accumulation of linear precursor. Notably, cdc2-I2 is spliced inefficiently even in cells containing wild-type U1, at least in part due to the presence of a stable hairpin encompassing its 5' splice site. Although point mutations at the 5' end of U1 have no discernible effect on splicing of pre-U6, significant accumulation of unspliced RNA is observed in a metabolic depletion experiment. Taken together, these observations indicate that the repertoire of U1 activities is used to varying extents for splicing of different pre-mRNAs in fission yeast.     

Effects of Interactions BetweenPasteurella haemolyticaandBordetella parapertussisonin vitroPhagocytosis by Lung Macrophages

The aim of the work was to determine the effect of exposing ovine bronchoalveolar macrophages (BAM)in vivotoPasteurella haemolyticaand/orBordetella parapertussison the subsequent uptake and killing ofP. haemolyticaby these cellsin vitro. Exposurein vivotoP. haemolyticadid not affect the uptake ofP. haemolyticaby BAMin vitrobut reduced (P< 0·05) the intracellular killing of bacteria. Exposurein vivotoB. parapertussishad no significant effect on either the uptake of killing ofP. haemolytica in vitro. However, sequential exposurein vivotoB. parapertussisandP. haemolyticareduced both the ingestion (P< 0·05) and killing (P< 0·001) ofP. haemolytica in vitro. These results indicate that exposure toP. haemolyticacompromised the bacterial killing mechanisms of BAM and that synergy betweenB. parapertussisandP. haemolyticareduced the ability of BAM to ingest bacteria.     

Sensitization of rhabdo-, lenti-, and spumaviruses to human serum by galactosyl(alpha1-3)galactosylation.

Vesicular stomatitis virus, human immunodeficiency virus type 2, and human foamy virus, which were produced by cell lines expressing galactosyl(alpha1-3)galactosyl (alphaGal) sugars, were found to be less stable in human serum than those from alphaGal-negative cells, indicating that galactosyl(alpha1-3)galactosylation sensitizes these viruses as well as mammalian type C oncoviruses (Rother et al., J. Exp. Med. 182:1345-1355, 1995; Takeuchi et al., Nature (London) 379:85-88, 1996) to complement killing via natural anti-alphaGal antibodies. Thus, virus killing mediated by anti-alphaGal antibodies may play a role as a barrier to animal-to-human infection of various enveloped viruses. Virus vectors for human in vivo gene therapy based on the viruses mentioned above should be produced from alphaGal-negative cells.