A constraint on historic growth in global photosynthesis due to increasing CO2.

The global terrestrial carbon sink is increasing1-3, offsetting roughly a third of anthropogenic CO2 released into the atmosphere each decade1, and thus serving to slow4 the growth of atmospheric CO2. It has been suggested that a CO2-induced long-term increase in global photosynthesis, a process known as CO2 fertilization, is responsible for a large proportion of the current terrestrial carbon sink4-7. The estimated magnitude of the historic increase in photosynthesis as result of increasing atmospheric CO2 concentrations, however, differs by an order of magnitude between long-term proxies and terrestrial biosphere models7-13. Here we quantify the historic effect of CO2 on global photosynthesis by identifying an emergent constraint14-16 that combines terrestrial biosphere models with global carbon budget estimates. Our analysis suggests that CO2 fertilization increased global annual photosynthesis by 11.85 ± 1.4%, or 13.98 ± 1.63 petagrams carbon (mean ± 95% confidence interval) between 1981 and 2020. Our results help resolve conflicting estimates of the historic sensitivity of global photosynthesis to CO2, and highlight the large impact anthropogenic emissions have had on ecosystems worldwide.

A trade-off between plant and soil carbon storage under elevated CO2.

Terrestrial ecosystems remove about 30 per cent of the carbon dioxide (CO2) emitted by human activities each year1, yet the persistence of this carbon sink depends partly on how plant biomass and soil organic carbon (SOC) stocks respond to future increases in atmospheric CO2 (refs. 2,3). Although plant biomass often increases in elevated CO2 (eCO2) experiments4-6, SOC has been observed to increase, remain unchanged or even decline7. The mechanisms that drive this variation across experiments remain poorly understood, creating uncertainty in climate projections8,9. Here we synthesized data from 108 eCO2 experiments and found that the effect of eCO2 on SOC stocks is best explained by a negative relationship with plant biomass: when plant biomass is strongly stimulated by eCO2, SOC storage declines; conversely, when biomass is weakly stimulated, SOC storage increases. This trade-off appears to be related to plant nutrient acquisition, in which plants increase their biomass by mining the soil for nutrients, which decreases SOC storage. We found that, overall, SOC stocks increase with eCO2 in grasslands (8 ± 2 per cent) but not in forests (0 ± 2 per cent), even though plant biomass in grasslands increase less (9 ± 3 per cent) than in forests (23 ± 2 per cent). Ecosystem models do not reproduce this trade-off, which implies that projections of SOC may need to be revised.

[Tarsal coalitions: a rare differential diagnosis of congenital clubfoot]. / Koalitionen des Rückfusses als seltene Differenzialdiagnosen des angeborenen Klumpfusses.

The Ponseti method has proven to be successful in the treatment of idiopathic congenital talipes equinovarus (clubfoot). In particular, if plaster cast treatment as recommended by Ponseti does not show the desired correction of the foot, tarsal coalitions as a rare cause for a secondary clubfoot deformity have to be ruled out. In these cases a surgical release of the coalition in addition to the tenotomy has to be performed to achieve a satisfactory correction.

Stress fracture of the talus following resection of a talocalcaneal coalition: a case report.

We report the case of a 15-year-old male with bilateral talocalcaneal coalition. Following resection of the symptomatic coalition, the patient developed a painful ankle. MR imaging revealed a stress fracture of the talar body. In this report we discuss presentation and treatment of a symptomatic talocalcaneal coalition complicated by a later stress fracture as well as a review of the literature.

Aromatic-dependent salmonella as anti-bacterial vaccines and as presenters of heterologous antigens or of DNA encoding them.

The development of live bacterial vaccines is reviewed, in particular aromatic-dependent Salmonella, either for protection against the corresponding infections (including typhoid fever) or as carrier-presenter of antigens of unrelated pathogens or of DNA specifying them. Aromatic-dependent Salmonella live vaccines are also compared with BCG and Ty21a and the recent records of exceptional situations are discussed in which aroA (deletion) strains of Salmonella typhimurium cause progressive disease in mice.

Role of the Salmonella abortusovis virulence plasmid in the infection of BALB/c mice.

Following oral inoculation of BALB/c mice, Salmonella abortusovis strain SS44 was recovered in lower numbers from the Peyer's patches and mesenteric lymph nodes compared with S. typhimurium strain SL1344, whereas splenic infections were equivalent between the two serovars. SS44 was cured of its virulence plasmid or subjected to mutagenesis of the spv genes, and the Spv(-) derivatives were tested for virulence in mice. Plasmid-cured S. abortusovis SU40 retained virulence in BALB/c mice when inoculated intraperitoneally. On the other hand, mice infected orally with SU40 had greatly reduced splenic infection compared to those infected with wild-type SS44. Similar results were obtained after Tn5 insertion mutagenesis of the spvR gene or deletion of the spvABCD locus. These results suggest that in the gut-associated lymphoid tissues S. abortusovis may replicate less than S. typhimurium and that the S. abortusovis virulence plasmid primarily affects systemic infection after oral inoculation but not after intraperitoneal administration in the mouse model.

Protection against experimental fowl typhoid by parenteral administration of live SL5828, an aroA-serC (aromatic dependent) mutant of a wild-type Salmonella Gallinarum strain made lysogenic for P22 sie.

A wild-type strain of Salmonella enterica serotype Gallinarum, lysogenized with P22 sie (superinfection-exclusion defective) was greatly attenuated for newly hatched or 21-day-old chickens. An aroA transductant of the lysogenic strain and an aroA-serC tetracycline-sensitive deletion or deletioninversion mutant of the latter were equally attenuated. Intramuscular administration of the aroA-serC strain to 21-day-old chickens protected them against oral challenge with 10(6) colony forming units of a highly virulent Gallinarum strain (no deaths in the 30 vaccinated chickens versus 14 of 30 in the control group). There was evidence of protection in the contents, mucosa and lymphoid tissue of the alimentary tract, in addition to that which occurred in the liver and spleen.A weak serological response was detected by enzyme-linked immunosorbent assay, indicating that use of such a strain is compatible with serological monitoring and would be a useful adjunct to control schemes for fowl typhoid.

Application of ribotyping and IS200 fingerprinting to distinguish the five Salmonella serotype O6,7:c:1,5 groups: Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis.

Sixty-seven strains of the five described Salmonella serotypes having antigens 6,7:c:1,5, that is S. enterica serotype Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis, were examined for 16S rrn profile ribotype, presence of IS200 and phenotypic characters, including rate of change of flagellar-antigen phase and nutritional character. Choleraesuis sensu stricto and its Kunzendorf variant had related but distinct ribotypes. Therefore, ribotyping appears to be a suitable method for differentiating Choleraesuis non-Kunzendorf from Choleraesuis var. Kunzendorf. Some strains of Paratyphi C had 16S profiles that resembled that of Choleraesuis non-Kunzendorf, while others resembled that of Choleraesuis var. Kunzendorf. The Typhisuis profiles were like those of Choleraesuis non-Kunzendorf, while the Choleraesuis var. Decatur profiles were unlike those of any of the other four groups. Furthermore, IS200 fingerprinting discriminated between Choleraesuis var. Decatur and the other strains with antigenic formula O6,7:c:1,5, and comparison of IS200 patterns showed a high degree of genetic divergence within Choleraesuis var. Decatur. Our findings show that ribotyping and IS200 fingerprinting, combined with classical microbiological methods, distinguish the groups Choleraesuis non-Kunzendorf, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C and Typhisuis.

Laser pyrolysis products-genotoxic, clastogenic and mutagenic effects of the particulate aerosol fractions.

Laser therapy has gained wide acceptance and application in many medical disciplines. Nevertheless, during surgical procedures, the thermal destruction of tissue creates a smoke plume. Recent research data indicate that pyrolysates liberated during vaporisation of tissue induce DNA damage. However, assessing potential health hazards during medical laser treatment requires comprehensive insight into the cytotoxic, genotoxic, clastogenic and mutagenic capacity of laser pyrolysis products (LPP). Therefore, the aim of this study was to evaluate the cytotoxic, genotoxic, clastogenic and mutagenic potential of substances resulting from laser irradiation. Four different types of porcine tissues were irradiated with a surgical CO2 laser, the aerosols were sampled under defined conditions and subjected to the SCE test, micronucleus test and the HPRT test. The results showed that the pyrolysis products are strong inducers of cytotoxic effects. The pyrolysis products induced positive effects in the SCE test, micronucleus test and the HPRT test. The ability and extent to induce genotoxic and mutagenic effects turned out to be dependent on the type of tissue that had been irradiated. In general, the effects were most pronounced with liver pyrolysate. In all test systems, a clear dose relationship could be established. In conclusion, we were able to prove that the particulate fraction of laser pyrolysis aerosols originating from biological tissues undoubtedly have to be classified as cytotoxic, genotoxic, clastogenic and mutagenic. Therefore, they could be potential health hazards for humans.

Immunosuppression and nitric oxide production induced by parenteral live Salmonella vaccines do not correlate with protective capacity: a phoP::Tn10 mutant does not suppress but does protect.

Previous work from our laboratory showed that an aroA mutant strain of S. typhimurium, SL3235, induces profound immunosuppression 7 days post-parenteral inoculation, and that the suppression is mediated by nitric oxide. Suppression was measured by the capacity of spleen cells to mount a primary in vitro plaque-forming cell response to sheep red blood cells in Mishell-Dutton cultures. In the present studies, the capacity of a panel of strains of attenuated Salmonella with various genetic lesions was tested. Most of the strains were S. typhimurium, but several were S. dublin. It was found that a variety of Salmonella strains induced suppression, demonstrating that suppressive capacity is not unique to SL3235 or to S. typhimurium. A strong correlation was obtained between the log10 of the microbial burden (cfu spleen-1) on the seventh day post-vaccine inoculation and the degree of immunosuppression. Strains that gave high spleen counts gave greater suppression. Microbial burden also correlated with the size of the spleen and the amount of nitrite produced by spleen-cell cultures, a measure of nitric oxide. Finally, the degree of immunosuppression was found to be linearly related to the log10 of the amount of nitrite produced. The capacity of the various strains of Salmonella to protect against challenge with virulent S. typhimurium, strain W118-2, was also tested. No correlation was found between suppressive and protective capacities of the various strains. Two strains suppressed, but did not protect. While most strains that protected grew or persisted in vivo, a phoP::Tn10 mutant of S. typhimurium did not grow or persist; this phoP mutant did not cause immunosuppression, but gave 100% protection against challenge with wild type S. typhimurium, suggesting that such mutants have advantageous properties as live vaccines.

Laser pyrolysis products: sampling procedures, cytotoxic and genotoxic effects.

The use of lasers in medical applications has grown enormously in the last few years. Recent chemical analysis of the laser pyrolysis products revealed that aerosols generated by pyrolytic decomposition of tissue could be health hazards. Therefore we analysed the genotoxic and mutagenic effects of laser pyrolysis products from different types of porcine tissue. The tissues were irradiated with a surgical CO2 laser and the generated aerosols were sampled as particulate fractions as well as low and highly volatile fractions. Then human leukocytes were incubated with the pyrolysis products and subjected to the comet assay. The results of the comet assay indicated the pyrolysis products being inducers of DNA damage. The ability to induce genotoxic effects turned out to be strongly dependent on the type of tissue that had been irradiated during laser treatment. To check whether the pyrolysis products also have mutagenic properties the Salmonella mutagenicity assay was performed. The particulate aerosol fractions of skin, muscle tissue and liver tissue clearly proved to be mutagenic in TA98 in the presence of S9 mix. There was no mutagenic effect detectable without metabolic activation. In conclusion, our experiments showed that the laser pyrolysis products originating from porcine tissues induced very potent genotoxic as well as mutagenic effects and therefore they could be potential health hazards for humans.

Results of the Kentucky high school football knee injury survey.

The study attempted to: 1) determine knee injury and reinjury incidence of Kentucky high school football players; 2) relate results to initial care provider, treatment following initial physician exam, time lost from injury, injury type, player position, and team size; and 3) assess coaches opinions and practices about lateral prophylactic knee brace (LPKB) usage and effectiveness. A post season, mail-in coaches' survey (50.2% return, 101/201) collected these data. Returned surveys represented 4690 players with average team size (x +/- SD) of 43 +/- 13. Two hundred fifty seven reported knee injuries yielded .055 knee injuries/player with .04 knee injuries/player being "new" and .015 knee injuries/player recurring (27% of reported knee injuries) during the season. Games accounted for 56.4% (56/101) of reported knee injuries. Coaches generally believed that LPKB usage prevented knee injuries (56.4%, 56/101) and allowed LPKB usage (92.1%, 93/101), however only 8.3% (8/101) required their wear (interior linemen 50%, linebackers 25%, entire team (25%). Interior linemen had the greatest number of knee injuries, followed by offensive backs and linebackers. Most knee injuries (81%, 208/257) were out 3-6 weeks or less, 64% (164/257) involved sprains or contusions, 38% (97/257) were treated surgically (alone or with rehabilitation) and 36% (92/257) were treated solely with rehabilitation. Total knee injury and reinjury incidence were under-estimated compared to existing reports. Improved injury recording methods, and post-symposia coaches evaluation are recommended.

Expression and immunogenicity of V3 loop epitopes of HIV-1, isolates SC and WMJ2, inserted in Salmonella flagellin.

Synthetic oligonucleotides corresponding to specific V3 loop portions of two HIV-1 isolates, SC and WMJ2, were expressed in the flagella of a Salmonella live-vaccine strain. Expression of the inserted epitopes in flagellin and their exposure at the surface of flagellar filaments were shown by immunoblotting and immunogold labeling with anti-flagellin (Salmonella d) and anti-HIV-1(IIIB) V3 loop peptide sera. Live recombinant Salmonella strains expressing either one of the two V3 loop inserts were administered intraperitoneally to BALB/c mice. All these animals developed antibodies specific for the heterologous glycoprotein 120 (gp120) of HIV-1 MN strain, as detected by enzyme-linked immunosorbent assays (ELISA), two of the sera had neutralizing activity against the heterologous HIV-1 MN strain. Moreover, oral administration of the live Salmonella recombinant strains to mice evoked specific IgA directed against gp120.

Changes in the repair capacity of blood cells as a biomarker for chronic low-dose exposure to ionizing radiation.

The purpose of this study was to examine whether changes in the repair capacity of blood cells could be used as a valuable biomarker for radiation exposure. To characterize the repair kinetics in nonirradiated and irradiated cells we first performed in vitro split dose experiments. DNA damage and DNA repair capacity were analysed using the comet assay. Our results showed that the first in vitro irradiation affects the repair system of the cells, resulting in a decreased repair capacity after the second irradiation. Furthermore, the second irradiation results in a large amount of DNA damage in the blood cells. To test whether the analysis of the DNA repair capacity after in vitro irradiation is also a valuable method for in vivo studies of donors exposed to radiation, we analysed the repair capacity of blood cells of two exposed groups: patients subjected to a radioiodine therapy and chronically irradiated volunteers from the Chernobyl region. Both groups also showed a significantly impaired repair capacity indicating a stress on the hematopoietic system. In addition, in the group of the Ukrainians DNA damage after in vitro irradiation was significantly higher than in a control group. These results lead to the presumption that the repair capacity and the DNA damage after in vitro irradiation might be a very useful biological marker for radiation exposure in population monitoring.

Immunogenicity of a fusion protein linking the beta subunit carboxyl terminal peptide (CTP) of human chorionic gonadotropin to the B subunit of Escherichia coli heat-labile enterotoxin (LTB).

Human chorionic gonadotropin (hCG) is currently under investigation as an antigenic target in both anti-cancer and anti-fertility vaccines. Formulations studied to date show promise in clinical trials for both applications yet are expensive to produce and require frequented administration in order to maintain an effective antibody titer. We have engineered a fusion protein consisting of Escherichia coli heat-labile enterotoxin subunit B (LTB) genetically linked at its C terminus via a nine amino acid linker to the 37 amino acid carboxyl terminal peptide (CTP) of the hCG beta chain. This LTB-CTP fusion protein is stably expressed in bacteria and forms pentamers of full-length protein subunits. Purified LTB-CTP protein hCG-specific antibodies in mice without additional adjuvants.

Protection against oral challenge three months after i.v. immunization of BALB/c mice with live Aro Salmonella typhimurium and Salmonella enteritidis vaccines is serotype (species)-dependent and only partially determined by the main LPS O antigen.

The role of the main LPS O antigen in the specificity of protection as mediated by systemic mechanisms following immunization with live attenuated Aro Salmonella vaccines was studied in mice. Innately Salmonella-susceptible (Itys) BALB/c mice were immunized intravenously with a single dose of either Salmonella typhimurium SL3261 aroA (LPS O4,5,12) or Salmonella enteritidis Se795aroA (LPS O1,9,12), and challenged orally 2-3 months later with either S. typhimurium C5 or S. enteritidis Thirsk. Nearly isogenic transductants of the two challenge strains expressing either their own LPS or that of the other serotype (S. typhimurium C5 O4 or O9, and S. enteritidis Thirsk O9 or O4) were also used. Both vaccines conferred similar high protection against the virulent strain of the homologous serotype expressing its own LPS. There was no protection against the heterologous serotype expressing its own LPS. However, when vaccinated mice were challenged with either the same serotype as the vaccine but expressing the heterologous LPS, or with the heterologous serotype expressing the LPS of the vaccine, protection was always lower than protection against the fully homologous serotype. Anti-smooth LPS antibodies showed higher titres against the homologous LPS, but with significant crossreactivity with the heterologous LPS. Antibodies to O-rough S. typhimurium and S. enteritidis LPS were present following immunization with either of the two vaccine strains. The LPS alone cannot fully account for the specificity of protection in this model; other (protein) antigens may be responsible. It remains to be seen whether there is a T-cell mediated component to the specificity of protection conferred by live Salmonella vaccines.

Effect of the surface composition of motile Escherichia coli and motile Salmonella species on the direction of galvanotaxis.

We have reported that motile Escherichia coli K-12 placed in an electric field swims toward the anode but that motile Salmonella typhimurium strains swim toward the cathode, a phenomenon called galvanotaxis (J. Adler and W. Shi, Cold Spring Harbor Symp. Quant. Biol. 53:23-25, 1988). In the present study, we isolated mutants with an altered direction of galvanotaxis. By further analyses of these mutants and by examination of E. coli and Salmonella strains with altered cell surface structure, we have now established a correlation between the direction of galvanotaxis and the surface structure of the cell: motile rough bacteria (that is, those without O polysaccharide; for example, E. coli K-12 and S. typhimurium mutants of classes galE and rfa) swam toward the anode, whereas motile smooth bacteria (that is, those with O polysaccharide; for example, wild-type S. typhimurium LT2) swam toward the cathode. However, smooth bacteria with acidic polysaccharide capsules (K1 in E. coli and Vi in Salmonella typhi) swam toward the anode. Measurements of passive electrophoretic mobility of strains representative of each set were made. We propose that the different directions of galvanotaxis of rough (or capsulate) bacteria and of smooth bacteria are explicable if the negative electrophoretic mobility of flagellar filaments is less than that of rough bodies but greater than that of smooth bodies.

Humoral immune responses to recombinant tree pollen allergens (Bet v I and Bet v II) in mice: construction of a live oral allergy vaccine.

Recombinant tree pollen allergens (recombinant Bet v I and recombinant birch profilin, Bet v II) were purified and used to immunize BALB/c and B6D2F1 mice with Al(OH)3 to elicit a specific IgE response. Serum from immunized mice was then used to detect immunoblotted natural tree pollen allergens. The onset of the humoral immune response was monitored using antimouse IgE, IgG1, IgG2a/b, IgG3 and IgA. In both strains, a specific and long-lasting IgE response could be elicited with both recombinant allergens. Mice immunized continuously with recombinant Bet v I + Al(OH)3 showed a significant decrease of specific IgE antibodies indicating that continuous application of allergens can reduce specific IgE responses. The possibility of inducing a different type of immune responses is indicated by the fact that mice fed with Bet v I expressed in apathogenic Salmonella strains showed a Th1 immune response to Bet v I accompanied by specific IgG2a/b without detectable IgG1 or IgE. Recombinant allergens can hence be used to decrease or even modulate specific IgE responses in vivo.

Expression and immunogenicity of an 18-residue epitope of HIV1 gp41 inserted in the flagellar protein of a Salmonella live vaccine.

A synthetic oligonucleotide specifying residues 735-752 of the product of the env gene of HIV1 IIIB was inserted by blunt-end ligation at restriction sites in the hypervariable, antigenically determinant region IV of two flagellin genes. Its integration, in frame and correct orientation, into gene fliC(d) in plasmid pLS408 allowed production of functional flagella when the plasmid was placed in a flagellin-negative aroA live-vaccine Salmonella dublin strain, SL5928. Bacteria thus made motile were immobilized and agglutinated by anti-(735-752 peptide) serum; expression was also shown by immunoelectron-microscopy and by Western blot of whole-cell lysates. Enzyme immunoassay (EIA) of sera of mice given three doses by intraperitoneal injection of the live-vaccine strain producing chimeric flagellin, or of concentrated flagella from it, showed production of antibody with affinity for the peptide, and in some sera, also for r-gp160. Pooled serum from mice given five i.p. doses of the live vaccine strain expressing the gp41 epitope at the surface of its flagellar filaments had higher titres of anti-peptide and anti-r-gp160 antibody and weak neutralizing activity on the IIIB isolate (90% neutralization at 1/100). The sera of nine mice given two doses of the live vaccine by the oral route had either no or only very low titres of antibody to flagellar antigen d; they were therefore not tested for anti-peptide activity.