Summer rainfall variability in European Mediterranean mountains from the sixteenth to the twentieth century reconstructed from tree rings

Since the end of the last glacial period, European Mediterranean mountains have provided shelter for numerous species of Eurosiberian and Boreal origin. Many of these species, surviving at the southern limit of their range in Europe and surrounded by Mediterranean ones, are relatively intolerant to summer drought and are in grave danger of loss, as a result of increasingly long and frequent droughts in this region. This is the case of the Scots pine (Pinus sylvestris) and the Austrian pine (Pinus nigra ssp. salzmannii) which are found on Central Iberian Peninsula at the edge of their natural range. We used a tree ring network of these two species to reconstruct past variations in summer rainfall. The reconstruction, based upon a tree ring composite chronology of the species, dates back to 1570 (adjusted R ²?=?0.49, P?<?0.000001) and captures interannual to decadal scale variability in summer precipitation. We studied the spatial representativeness of the rainfall patterns and described the occurrence rate of extremes of this precipitation. To identify associations between macroclimatic factors and tree radial growth, we employed a principal component analysis to calculate the resultant of the relationship between the growth data of both species, using this resultant as a dependent variable of a multiple regression whose independent variables are monthly mean temperature and precipitation from the average records. Spatial correlation patterns between instrumental precipitation datasets for southern Europe and reconstructed values for the 1950–1992 period indicate that the reconstruction captures the regional signal of drought variability in the study region (the origin of this precipitation is convective: thermal low pressure zones induced in the inland northeastern areas of the Iberian Peninsula). There is a clear increase in the recurrence of extreme dry events as from the beginning of twentieth century and an abrupt change to drier conditions. There appears to be a tendency toward recurrent exceptionally dry summers, which could involve a significant change for the Eurosiberian refugee species.     

Floristic relationship between scrubland and grassland patches in the Mediterranean landscape of the Iberian Peninsula

In the rural Mediterranean landscape, mosaics of patches of sclerophyllous scrubland and semi-natural grasslands are frequent. The plant communities of these patches, which are physiognomically easy to recognise, are very heterogeneous. The objective of this paper is to determine whether the patches of scrub-grassland represent an integrated response unit of the vegetation with regard to the physical environment (climatic, geographical and edaphic factors) and human use, or whether, on the contrary, this is an independent response. In order to do this a total of 50 sampling sites where scrubland and grassland patches were in contact were studied along a 370 km E-W mesoclimatic gradient from central Spain to Portugal (Iberian Peninsula). Two distinct zones, the east and the west halves of the study area, were identified according to the plant communities. Within each of these zones, each type of patch responded to the previously mentioned factors, differentially and independently. This determined a general lack of inter-community association or floristic correlation between scrub and grassland plant communities in contact. The spatial association is a random process probably related to the particular human management realised on every scrubland and grassland patch. The scrub–grassland pattern, which is characteristic of the Mediterranean landscape, does not represent an integrated response unit of the vegetation to a given environment, but rather the sum of the independent responses to the environment of the two patches in contact.Nomenclature for taxa: T. G. Tutin et al. 1694–1980. Flora Europaea Cambridge University Press, Cambridge.     

Damming reduced the functional richness and caused the shift to a new functional state of the phytoplankton in a subtropical region

Hydrobiologia - We analyzed the effect of damming on the temporal patterns of the composition and richness of phytoplankton Reynolds functional groups (RFG) from a subtropical floodplain, together...     

Pravastatin immunomodulates IL-6 and C-reactive protein, but not IL-1 and TNF-alpha, in cardio-pulmonary bypass

BACKGROUND: While statins are increasingly used in cardiopulmonary bypass (CPB), the anti-inflammatory effects of individual statins, within the context of various treatment regimes, need further examination. The present study evaluates the anti-inflammatory effectiveness of the short-term, preoperative and intensive postoperative use of pravastatin in CPB. METHOD: Forty three patients undergoing CPB were enrolled in a randomized, prospective clinical study. One group (n = 21), received pravastatin, the other (n = 22) did not. Patients in the pravastatin group received one dose of 40 mg per day for nine days, starting 48 hours before CPB, with an additional dose of 40 mg one hour after surgery. Plasma levels of selected inflammatory mediators were measured at baseline and tracked systematically. RESULTS: Pravastatin reduced postoperative interleukin-6 (IL-6) levels significantly at 24 and 48 hours, and at seven days. Mean +/- SD values, for treated versus untreated patients were: at 24 hours, 159.5 +/- 58.5 versus 251.2 +/- 53.0 pg/mL (p < 0.001); at 48 hours, 81.9 +/- 31.5 versus 194.2 +/- 56.3 pg/mL (p < 0.001); and at seven days, 16.4 +/- 7.2 versus 30.8 +/- 12.6 (p < 0.001). C-reactive protein (CRP) decreased significantly on the seventh postoperative day, when plasma levels were 3.6 +/- 1.1 in the treated patients versus 8.2 +/- 2.1 mg/dL in the controls (p < 0.001). No changes in plasma IL-1 and TNF-alpha were found during entire study. CONCLUSIONS: Pravastatin induced a precocious modulation of IL-6 expression and a later reduction of plasma CRP levels. Pravastatin;s effects on the expression of these pivotal inflammatory mediators strongly support its well-timed use in CPB.     

Characterization of virus infectivity and cell-free capsid assembly of SIVMneCL8

We have previously described a cell-free system that reconstitutes immature capsid assembly of Gag polypeptides from viruses belonging to three major primate lentiviral lineages, including HIV-1, HIV-2 and SIVagm. Studies described here examine a member of the SIVmac/Mne lineage, SIVMneCL8, using assays for virus production and infectivity as well as cellular events in capsid formation. We report that SIVMneCL8, a molecular clone with properties typical of transmitted viral variants, is less infectious per unit p27 Gag than another member of the SIVmac/Mne lineage, SIVmac239. SIVMneCL8 Gag polypeptides are arrested at an early stage of capsid assembly in the cell-free system. Additionally, SIVMneCL8 Gag polypeptides associate minimally with the host factor human HP68. This is the first report of a primate lentivirus that does not complete capsid assembly in the cell-free system.     

Snake bites accidents in Yopal and Leticia, Colombia, 1996-1997

Snakebites produce notable morbidity and mortality in the Amazonian and Orinocan regions of Colombia. A review was undertaken of 56 snakebite cases sent to hospitals in Leticia (Amazonas) and Yopal (Casanare) between September 1996 and June 1997. Of the total, 57% of the bites occurred in Leticia, 54% in men. The 14 to 44 year-old age group was most compromised (41%). Most encounters occurred in forests and open fields between 17:00 and 18:00 hours (57%). Nearly all bites were located on legs and feet (82%). One death occurred in Yopal; 3 fasciotomies and 2 amputations were performed. Snakebite incidence occurred with highest probability during evening hours. Although antibiotics are in general use, minor infections (16%) were frequent.     

A set of simple-sequence repeat (SSR) markers covering the Prunus genome

A set of 109 microsatellite primer pairs recently developed for peach and cherry have been studied in the almond x peach F(2) progeny previously used to construct a saturated Prunus map containing mainly restriction fragment length polymorphism markers. All but one gave amplification products, and 87 (80%) segregated in the progeny and detected 96 loci. The resulting Prunus map contains a total of 342 markers covering a total distance of 522 cM. The approximate position of nine additional simple sequence repeats (SSRs) was established by comparison with other almond and peach maps. SSRs were placed in all the eight linkage groups of this map, and their distribution was relatively even, providing a genome-wide coverage with an average density of 5.4 cM/SSR. Twenty-four single-locus SSRs, highly polymorphic in peach, and each falling within 24 evenly spaced approximately 25-cM regions covering the whole Prunus genome, are proposed as a 'genotyping set' useful as a reference for fingerprinting, pedigree and genetic analysis of this species.     

Molecular characterization of 3-phosphoglycerate dehydrogenase deficiency--a neurometabolic disorder associated with reduced L-serine biosynthesis

3-phosphoglycerate dehydrogenase (PHGDH) deficiency is a disorder of L-serine biosynthesis that is characterized by congenital microcephaly, psychomotor retardation, and seizures. To investigate the molecular basis for this disorder, the PHGDH mRNA sequence was characterized, and six patients from four families were analyzed for sequence variations. Five patients from three different families were homozygous for a single nucleotide substitution predicted to change valine at position 490 to methionine. The sixth patient was homozygous for a valine to methionine substitution at position 425; both mutations are located in the carboxyterminal part of PHGDH. In vitro expression of these mutant proteins resulted in significant reduction of PHGDH enzyme activities. RNA-blot analysis indicated abundant expression of PHGDH in adult and fetal brain tissue. Taken together with the severe neurological impairment in our patients, the data presented in this paper suggest an important role for PHGDH activity and L-serine biosynthesis in the metabolism, development, and function of the central nervous system.