Human antibodies react with an epitope of the human papillomavirus type 6b L1 open reading frame which is distinct from the type-common epitope.

Recombinant proteins encoded by the human papillomavirus type 6b (HPV6b) L1 open reading frame react with sera from patients with condylomata acuminata and also react with rabbit antiserum raised against sodium dodecyl sulfate-disrupted bovine papillomavirus type 1 (BPV1) virions. To map the immunoreactive epitopes, a series of procaryotic expression plasmids was made which contained a nested set of 3' to 5' deletions in the HPV6b L1 open reading frame. The deleted plasmids expressed a set of carboxy to amino terminus truncated fusion proteins. Regions containing the immunoreactive epitopes were mapped by determining which of the deleted fusion proteins retained reactivity with sera in Western immunoblot assays. The coding sequence for a human antibody-reactive linear epitope mapped between HPV6b nucleotide coordinates 7045 and 7087, and the rabbit anti-BPV1-reactive epitope coding sequence mapped between coordinates 6377 and 6454. Synthetic peptides derived from the epitope mapping were reacted with sera in enzyme-linked immunosorbent assay. Human sera reacted with synthetic peptide QSQAITCQKPTPEKEKPDPYK (HPV6b L1 amino acids 417 through 437). Rabbit anti-BPV1 and rabbit antisera raised against HPV16 L1 recombinant proteins reacted with the synthetic peptide DGDMVDTGFGAMNFADLQTNKSDVPIDI (HPV6b L1 amino acids 193 through 220). Human sera which reacted with HPV6b L1 fusion proteins cross-reacted with an HPV11 L1 fusion protein but did not react with fusion proteins encoded by HPV1a, HPV16, or HPV18. Rabbit anti-BPV1 reacted with L1 fusion proteins encoded by all of these HPV types. In contrast to the type-common (rabbit anti-BPV1-reactive) epitope, the human antibody-reactive epitope appears to be relatively HPV type specific.     

Nitrogen and phosphorus budgets of the North Atlantic Ocean and its watershed

Anthropogenic food and energy production extensively mobilize reactive nitrogen (N) in the watershed of the North Atlantic Ocean (NAO). There is wide spread N distribution by both hydrologic and atmospheric processes within the watershed of the NAO, resulting in reactive N accumulation in terrestrial systems. Net denitrification in most estuaries and continental shelves exceeds the amount of N supplied to the shelves by rivers and requires a supply of nitrate from the open ocean. Thus riverine N is only transported to the open ocean in a few areas with the flow from a few major rivers (e.g., Amazon). Atmospheric N deposition to the open ocean has increased and may increase the productivity of the surface ocean. In addition, as a consequence of increased Fe deposition to the open ocean (due in part to anthropogenic processes), the rate of biological N-fixation may have increased resulting in N accumulation in the ocean. Phosphorus (P) is also mobilized by anthropogenic processes (primarily food production). Relative to N, more of the P is transported across the shelf to the open ocean from both estuaries and major rivers. There are several consequences of the increased availability of N and P that are unique to each element. However, the control on primary productivity in both coastal and open ocean ecosystems is dependent on a complex and poorly understood interaction between N and P mobilization and availability.     

Skeletal asymmetry and hand preference during termite fishing by gombe chimpanzees

Skeletons of chimpanzees with recorded life stories allow assessment of the potential relationships among hard tissue features and expressed behaviors. We analyze bone size, weight, and mineralization to assess osteological characters for identification of laterality of expressed behaviors involving the upper body. Results show that associations are not yet clearly defined.     

Construction and use of a nontoxigenic strain of Pseudomonas aeruginosa for the production of recombinant exotoxin A.

To express recombinant forms of Pseudomonas aeruginosa exotoxin A in high yield, we have developed a nontoxigenic strain of P. aeruginosa derived from the hypertoxigenic strain PA103. The nontoxigenic strain, designated PA103A, was produced by the excision marker rescue technique to replace the toxA structural gene in PA103 with an insertionally inactivated toxA gene. The PA103A strain (ToxA-) was used subsequently as the host strain for the expression and production of several recombinant versions of exotoxin A, and the results were compared with exotoxin A production in other P. aeruginosa and Escherichia coli strains. Use of the PA103A strain transformed with the high-copy-number pRO1614 plasmid bearing various toxA alleles resulted in final purification yields of exotoxin A averaging 23 mg/liter of culture. By comparison, exotoxin A production in other expression systems and host strains yields approximately 1/4 to 1/10 as much toxin.     

Purification of rabbit bone inhibitor of collagenase.

1. Rabbit bones in tissue culture synthesize an inhibitor of collagenase during the first 4 days of culture. 2. The inhibitor was purified by a combination of gel filtration, concanavalin A--Sepharose chromatography, ion-exchange chromatography and zinc-chelate affinity chromatography. 3. The purified inhibitor migrated as a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had a mol.wt. of 28000. 4. The inhibitor blocked the activity of the metalloproteinases collagenase, gelatinase, neutral proteinase III (proteoglycanase), human leucocyte collagenase and gelatinase, but not thermolysin or bacterial collagenase. The serine proteinases plasmin and trypsin were not inhibited. 5. The inhibitor interacted with purified rabbit bone collagenase with 1:1 stoichiometry. 6. The inhibitory activity was lost after incubation for 1 h at 90 degrees C, after treatment with trypsin (250 micrograms/ml) at 37 degrees C for 30 min and after reduction and alkylation.     

The E6 and E7 genes of human papillomavirus type 6 have weak immortalizing activity in human epithelial cells.

Previous studies have shown that the E7 gene of human papillomavirus (HPV) type 16 or 18 alone was sufficient for immortalization of human foreskin epithelial cells (HFE) and that the efficiency was increased in cooperation with the respective E6 gene, whereas the HPV6 E6 or E7 gene was not active in HFE. To detect weak immortalizing activities of the HPV6 genes, cells were infected with recombinant retroviruses containing HPV genes, alone and in homologous and heterologous combinations. The HPV6 genes, alone or together (HPV6 E6 plus HPV6 E7), were not able to immortalize cells. However the HPV6 E6 gene, in concert with HPV16 E7, increased the frequency of immortalization threefold over that obtained with HPV16 E7 alone. Interestingly, 6 of 20 clones containing the HPV16 E6 gene and the HPV6 E7 gene were immortalized, whereas neither gene alone was sufficient. Thus, the HPV6 E6 and E7 genes have weak immortalizing activities which can be detected in cooperation with the more active transforming genes of HPV16. Acute expression of the HPV6 and HPV16 E6 and E7 genes revealed that only HPV16 E7 was able to stimulate the proliferation of cells in organotypic culture, resulting in increased expression of the proliferative cell nuclear antigen and the formation of a disorganized epithelial layer. Additionally, combinations of genes that immortalized HFE cells (HPV16 E6 plus HPV16 E7, HPV16 E6 plus HPV6 E7, and HPV6 E6 plus HPV16 E7) also stimulated proliferation.     

Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Estimating Leptospirosis Incidence Using Hospital-Based Surveillance and a Population-Based Health Care Utilization Survey in Tanzania

Background

The incidence of leptospirosis, a neglected zoonotic disease, is uncertain in Tanzania and much of sub-Saharan Africa, resulting in scarce data on which to prioritize resources for public health interventions and disease control. In this study, we estimate the incidence of leptospirosis in two districts in the Kilimanjaro Region of Tanzania.

Methodology/Principal Findings

We conducted a population-based household health care utilization survey in two districts in the Kilimanjaro Region of Tanzania and identified leptospirosis cases at two hospital-based fever sentinel surveillance sites in the Kilimanjaro Region. We used multipliers derived from the health care utilization survey and case numbers from hospital-based surveillance to calculate the incidence of leptospirosis. A total of 810 households were enrolled in the health care utilization survey and multipliers were derived based on responses to questions about health care seeking in the event of febrile illness. Of patients enrolled in fever surveillance over a 1 year period and residing in the 2 districts, 42 (7.14%) of 588 met the case definition for confirmed or probable leptospirosis. After applying multipliers to account for hospital selection, test sensitivity, and study enrollment, we estimated the overall incidence of leptospirosis ranges from 75–102 cases per 100,000 persons annually.

Conclusions/Significance

We calculated a high incidence of leptospirosis in two districts in the Kilimanjaro Region of Tanzania, where leptospirosis incidence was previously unknown. Multiplier methods, such as used in this study, may be a feasible method of improving availability of incidence estimates for neglected diseases, such as leptospirosis, in resource constrained settings.