Effects of rodents on plant cover,soil hardness,and soil nutrient content: a case study on tuco-tucos (Ctenomys minutus)

We analyzed the effects of tuco-tucos (Ctenomys minutus, Ctenomyidae) on plant cover, plant biomass, soil hardness, soil pH, and variables related to nutrient disposition (P, K, Mg, and Ca), using data from three areas in the South Brazilian coastal plain. In each area, samples were taken from sites with and without C. minutus and results are presented in a concatenate way. Our results show that the presence of C. minutus modifies total plant biomass, grass cover, bare soil, soil hardness, soil pH, and nutrient content. Soils horizons at the depths of 10 and 20 cm are significantly softer in sites with C. minutus and phosphorus and potassium had higher concentrations. The content of magnesium and calcium were not affected. Soil pH was significantly lower where tuco-tucos occurred. Altogether, our results show that these animals may have a significant effect on vegetation composition and dynamics as well as on soil properties.     

Cloning and functional expression of the first Drosophila melanogaster sulfakinin receptor DSK-R1

Described in this report is a successful cloning and characterization of a functionally active Drosophila sulfakinin receptor designated DSK-R1. When expressed in mammalian cells, DSK-R1 was activated by a sulfated, Met(7-->Leu(7)-substituted analog of drosulfakinin-1, FDDY(SO(3)H)GHLRF-NH(2) ([Leu(7)]-DSK-1S). The interaction of [Leu(7)]-DSK-1S with DSK-R1 led to a dose-dependent intracellular calcium increase with an EC(50) in the low nanomolar range. The observed Ca(2+) signal predominantly resulted from activation of pertussis toxin (PTX)-insensitive signaling pathways pointing most likely to G(q/11) involvement in coupling to the activated receptor. The unsulfated [Leu(7)]-DSK-1 was ca. 3000-fold less potent than its sulfated counterpart which stresses the importance of the sulfate moiety for the biological activity of drosulfakinin. The DSK-R1 was specific for the insect sulfakinin since two related vertebrate sulfated peptides, human CCK-8 and gastrin-II, were found inactive when tested at concentrations up to 10(-5) M. To our knowledge, the cloned DSK-R1 receptor is the first functionally active Drosophila sulfakinin receptor reported to date.     

Why Was the 2009 Influenza Pandemic in England So Small?

The "Swine flu" pandemic of 2009 caused world-wide infections and deaths. Early efforts to understand its rate of spread were used to predict the probable future number of cases, but by the end of 2009 it was clear that these predictions had substantially overestimated the pandemic's eventual impact. In England, the Health Protection Agency made announcements of the number of cases of disease, which turned out to be surprisingly low for an influenza pandemic. The agency also carried out a serological survey half-way through the English epidemic. In this study, we use a mathematical model to reconcile early estimates of the rate of spread of infection, weekly data on the number of cases in the 2009 epidemic in England and the serological status of the English population at the end of the first pandemic wave. Our results reveal that if there are around 19 infections (i.e., seroconverters) for every reported case then the three data-sets are entirely consistent with each other. We go on to discuss when in the epidemic such a high ratio of seroconverters to cases of disease might have been detected, either through patterns in the case reports or through even earlier serological surveys.     

Comparison of the (CCG)4-based PCR and MIRU-VNTR for molecular typing of Mycobacterium avium strains

Mycobacterium avium, a member of the group of non-tuberculous mycobacteria, is most often responsible for the serious diseases in humans and is frequently isolated from NTM-caused pulmonary events. In this connection the epidemiological aspect is also of great importance. Here we present a useful genetic assay that uses (CCG)(4)-based PCR for genotyping M. avium. After applying this test to 33 strains of M. avium, we found a discriminatory index of 0.979. The accuracy of this analysis was supported by a reasonable reproducibility of 95.1%. These results were compared with the Mycobacterial Intergenic Repeat Unit-Variable Number Tandem Repeats (MIRU-VNTR) typing scheme which had slightly lower discriminatory index of 0.945 however, the method was able to cluster different strains compared to CCG-PCR. Taking into account high discriminatory index and reproducibility, this test scheme has the potential as a screening tool in the investigation of M. avium infections, especially if combined with MIRU-VNTR.     

Physiological predisposition of various Clostridium species to synthetize 1,3-propanediol from glycerol

1,3-Propanediol (1,3-PD) production by fermentation of glycerol was first described in 1881 but little attention was paid to this biosynthesis for over a century. An increasing interest in microbial 1,3-PD production is observed since late 1980s. The high growth rate of the biofuel market and the perspective of glycerol becoming abundant attract even more attention to this valuable chemical.Glycerol conversion to 1,3-PD is known to occur in Clostridia, Enterobacteriaceae and Lactobacillaceae. Some clostridial species are among the best 1,3-PD producers.This work is a review of the current state of research on Clostridium spp. strains that ferment glycerol to 1,3-PD. It focuses on the metabolic pathways and factors that influence the production of this diol. The effects of different environmental stresses on the process of 1,3-PD synthesis are also covered. Moreover, various genetic engineering methods utilized in order to improve the capabilities of bacteria used in this process are presented.     

The influence of radiotherapy on ceruloplasmin and transferrin in whole blood of breast cancer patients

Ceruloplasmin and transferrin are proteins which play a potential role in the process of breast cancer development. These molecules contain Cu²⁺ (ceruloplasmin) or Fe³⁺ ions (transferrin) and thus constitute paramagnetic centers, which can be studied using electron paramagnetic resonance method. The aim of the study was to determine how paramagnetic centers in whole blood of breast cancer patients change under the influence of radiation therapy. Samples of whole blood were taken from 17 women with breast cancer treated with radiotherapy. The measurements were carried out at 170 K using X-band electron paramagnetic resonance (EPR) spectrometer Bruker EMX-10. Two distinct EPR lines, derived from high-spin Fe³⁺ in transferrin and Cu²⁺ from ceruloplasmin, were revealed in all frozen samples. The amplitude and integrated intensity of the EPR signal from Cu²⁺ in ceruloplasmin significantly decreased in all patients after the delivery of the radiation fraction. When comparing the integral intensity of the signal from Fe³⁺ in transferrin, three different situations were identified which are patient specific: a significant increase, an insignificant change, or a significant decrease after the irradiation. A decreased level of Cu²⁺ from ceruloplasmin in patients after radiotherapy means a low level of ceruloplasmin in the plasma or an increased content of reduced Cu⁺ ions. Differences in the integrated intensity of the EPR signal from transferrin translate directly into the amount of bound iron. The observed changes could indicate how well the organism fights against cancer and how easily it adapts to the situation of biochemical stress.     

The activity of thymidine phosphorylase correlates with tumor size and lymph nodes status in breast carcinoma

The platelet-derived endothelial cell growth factor (PD-ECGF) is one of the potent angiogenic factors. Recently, its homology with thymidine phosphorylase (dThdPase), an enzyme involved in pyrimidine nucleoside metabolism, has been shown. In the present study, dThdPase activity was evaluated spectrophotometrically in 43 breast carcinomas and in 19 cases of non-neoplastic breast tissues. The mean dThdPase activity in breast cancer was almost six fold higher than in normal, non-neoplastic breast tissues (1.92 and 0.29 mumol thymine (T) x mg prot.-1 x h-1 respectively). The enzyme activity significantly correlated with axillary lymph node status (p = 0.0076) and with tumor size (p = 0.0099). Besides, the intratumoral microvessel density (MD) was evaluated using the CD 31 mouse anti-human monoclonal antibody, and there was no correlation between the level of enzymatic activity and a number of microvessels. The positive significant correlation of thymidine phosphorylase activity with prognostic factors in breast cancer patients with no relation to the number of microvessels needs further examination to confirm the prognostic significance of the level of dThdPase.     

Peptide dose, MHC affinity, and target self-antigen expression are critical for effective immunotherapy of nonobese diabetic mouse prediabetes

Cross-reactive T cells that recognize both Tep69 (dominant nonobese diabetic (NOD) T cell epitope in ICA69 (islet cell autoantigen of 69 kDa)) and ABBOS (dominant NOD T cell epitope in BSA) are routinely generated during human and NOD mouse prediabetes. Here we analyzed how systemic administration of these mimicry peptides affects progressive autoimmunity in adoptively transferred and cyclophosphamide-accelerated NOD mouse diabetes. These models were chosen to approximate mid to late stage prediabetes, the typical status of probands in human intervention trials. Unexpectedly, high dose (100 microg) i.v. ABBOS prevented, while Tep69 exacerbated, disease in both study models. Peptide effects required cognate recognition of endogenous self-Ag, because both treatments were ineffective in ICA69null NOD congenic mice adoptively transferred with wild-type, diabetic splenocytes. The affinity of ABBOS for NOD I-A(g7) was orders of magnitude higher than that of Tep69. This explained 1) the expansion of the mimicry T cell pool following i.v. Tep69, 2) the long-term unresponsiveness of these cells after i.v. ABBOS, and 3) precipitation of the disease after low dose i.v. ABBOS. Disease precipitation and prevention in mid to late stage prediabetes are thus governed by affinity profiles and doses of therapeutic peptides. ABBOS or ABBOS analogues with even higher MHC affinity may be candidates for experimental intervention strategies in human prediabetes, but the dose translation from NOD mice to humans requires caution.