Rosetta's comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature.

The Rosetta spacecraft has investigated comet 67P/Churyumov-Gerasimenko from large heliocentric distances to its perihelion passage and beyond. We trace the seasonal and diurnal evolution of the colors of the 67P nucleus, finding changes driven by sublimation and recondensation of water ice. The whole nucleus became relatively bluer near perihelion, as increasing activity removed the surface dust, implying that water ice is widespread underneath the surface. We identified large (1500 square meters) ice-rich patches appearing and then vanishing in about 10 days, indicating small-scale heterogeneities on the nucleus. Thin frosts sublimating in a few minutes are observed close to receding shadows, and rapid variations in color are seen on extended areas close to the terminator. These cyclic processes are widespread and lead to continuously, slightly varying surface properties.

Detection of (1→3)-ß-D-glucan in same-day urine and serum samples obtained from patients with haematological malignancies.

Serum 1,3-beta-d-glucan (BDG) testing is an established diagnostic marker for invasive fungal infections (IFI) among patients with haematological malignancies. In contrast limited data exist regarding the application of urine BDG testing. Same-day midstream urine and serum screening samples were collected in adult patients with underlying haematological malignancies. A total of 80 urine samples from 46 patients were investigated: Twenty-six had positive corresponding serum BDG >120 pg ml(-1), 27 intermediate (60-80 pg ml(-1)), and 27 negative serum BDG (<25 pg ml(-1)). A significant positive correlation between BDG in serum and urine samples was observed (P = 0.025; r = 0.252). Sensitivity, specificity, positive predictive value and negative predictive value (compared with same-day serum results) were: 42%, 76%, 46%, 73% when using an 80 pg ml(-1) urine cut-off, and 35%, 96%, 82%, 75% for a 250 pg ml(-1) cut-off. Urine BDG seemed to be higher in samples obtained from patients with probable IFI (n = 13, median 145, IQR 22-253) compared to those from patients without IFI (n = 56, median 24, IQR 15-88) but the difference was not significant (P = 0.069). Overall correlation of same-day urine BDG and serum BDG was moderate. However, urine BDG testing may warrant further investigation in larger studies, as high-positive urine results correlated with high-positive corresponding serum levels and clinical performance was comparable to serum BDG.

Properties of Bacillus megaterium and Bacillus subtilis mutants which lack the protease that degrades small, acid-soluble proteins during spore germination.

During germination of spores of Bacillus species the degradation of the spore's pool of small, acid-soluble proteins (SASP) is initiated by a protease termed GPR, the product of the gpr gene. Bacillus megaterium and B. subtilis mutants with an inactivated gpr gene grew, sporulated, and triggered spore germination as did gpr+ strains. However, SASP degradation was very slow during germination of gpr mutant spores, and in rich media the time taken for spores to return to vegetative growth (defined as outgrowth) was much longer in gpr than in gpr+ spores. Not surprisingly, gpr spores had much lower rates of RNA and protein synthesis during outgrowth than did gpr+ spores, although both types of spores had similar levels of ATP. The rapid decrease in the number of negative supertwists in plasmid DNA seen during germination of gpr+ spores was also much slower in gpr spores. Additionally, UV irradiation of gpr B. subtilis spores early in germination generated significant amounts of spore photoproduct and only small amounts of thymine dimers (TT); in contrast UV irradiation of germinated gpr+ spores generated almost no spore photoproduct and three to four times more TT. Consequently, germinated gpr spores were more UV resistant than germinated gpr+ spores. Strikingly, the slow outgrowth phenotype of B. subtilis gpr spores was suppressed by the absence of major alpha/beta-type SASP. These data suggest that (i) alpha/beta-type SASP remain bound to much, although not all, of the chromosome in germinated gpr spores; (ii) the alpha/beta-type SASP bound to the chromosome in gpr spores alter this DNA's topology and UV photochemistry; and (iii) the presence of alpha/beta-type SASP on the chromosome is detrimental to normal spore outgrowth.

Immunogenetics of human American cutaneous leishmaniasis. Study of HLA haplotypes in 24 families from Venezuela.

Twenty-four families with one or multiple cases of localized cutaneous leishmaniasis (LCL) from an endemic region with the highest incidence of LCL in Venezuela were typed from HLA-ABC, DR, DQ antigens and complement factors. The parental HLA haplotypes segregated at random among healthy and affected siblings but in backcross families significantly higher frequencies of HLA-A28 (p = 0.0018), -Bw22 (p = 0.0122), or -DQw8 (p = 0.0364) were present in affected compared to healthy siblings. HLA-B15 showed a higher frequency (p = 0.0062) among the latter group. Haplotypes Bw22CF31 (p = 0.0076) and Bw22DRw11DQw7 (p = 0.0163) were also significantly more frequent in affected compared to healthy siblings and A2Cw- (p = 0.0445) among the latter. No HLA genetic linkage with a putative LCL susceptibility gene(s) could be demonstrated in this study. A case/control comparison of 26 unrelated LCL patients (one proband from each family) and healthy individuals of the same ethnic origin confirmed the association of HLA-Bw22 (pc = 0.048) and -DQw3 (pc = 0.036) with LCL. The relative risk reached 12.5 for Bw22 and 4.25 for DQw3 with ethiologic factors of 0.17 and 0.64, respectively. HLA-DQw3 apparently makes the major contribution as a genetic risk factor for LCL at the population level.