The presence of professional phagocytes dictates the number of host cells targeted for Yop translocation during infection

Type III secretion systems deliver effector proteins from Gram‐negative bacterial pathogens into host cells, where they disarm host defences, allowing the pathogens to establish infection. Although Yersinia pseudotuberculosis delivers its effector proteins, called Yops, into numerous cell types grown in culture, we show that during infection Y. pseudotuberculosis selectively targets Yops to professional phagocytes in Peyer's patches, mesenteric lymph nodes and spleen, although it colocalizes with B and T cells as well as professional phagocytes. Strikingly, in the absence of neutrophils, the number of cells with translocated Yops was significantly reduced although the bacterial loads were similar, indicating that Y. pseudotuberculosis did not arbitrarily deliver Yops to the available cells. Using isolated splenocytes, selective binding and selective targeting to professional phagocytes when bacteria were limiting was also observed, indicating that tissue architecture was not required for the tropism for professional phagocytes. In isolated splenocytes, YadA and Invasin increased the number of all cells types with translocated Yops, but professional phagocytes were still preferentially translocated with Yops in the absence of these adhesins. Together these results indicate that Y. pseudotuberculosis discriminates among cells it encounters during infection and selectively delivers Yops to phagocytes while refraining from translocation to other cell types.     

NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high‐level pathogen resistance under greenhouse and field conditions

Plant defensins are small cysteine‐rich peptides that inhibit the growth of a broad range of microbes. In this article, we describe NmDef02, a novel cDNA encoding a putative defensin isolated from Nicotiana megalosiphon upon inoculation with the tobacco blue mould pathogen Peronospora hyoscyami f.sp. tabacina. NmDef02 was heterologously expressed in the yeast Pichia pastoris, and the purified recombinant protein was found to display antimicrobial activity in vitro against important plant pathogens. Constitutive expression of NmDef02 gene in transgenic tobacco and potato plants enhanced resistance against various plant microbial pathogens, including the oomycete Phytophthora infestans, causal agent of the economically important potato late blight disease, under greenhouse and field conditions.     

Genetic structure and ecogeographical adaptation in wild barley (<Emphasis Type="Italic">Hordeum chilense</Emphasis>Roemer et Schultes) as revealed by microsatellite markers

Background  

Multi-allelic microsatellite markers have become the markers of choice for the determination of genetic structure in plants. Synteny across cereals has allowed the cross-species and cross-genera transferability of SSR markers, which constitute a valuable and cost-effective tool for the genetic analysis and marker-assisted introgression of wild related species. Hordeum chilense is one of the wild relatives with a high potential for cereal breeding, due to its high crossability (both interspecies and intergenera) and polymorphism for adaptation traits. In order to analyze the genetic structure and ecogeographical adaptation of this wild species, it is necessary to increase the number of polymorphic markers currently available for the species. In this work, the possibility of using syntenic wheat SSRs as a new source of markers for this purpose has been explored.     

CyberKnife radiosurgery for inoperable stage IA non-small cell lung cancer: 18F-fluorodeoxyglucose positron emission tomography/computed tomography serial tumor response assessment

Abstract

Management of localized primary gastric B lymphoma (PGL) remains controversial. The aim of this study is to compare two treatments: chemotherapy alone and surgery plus chemotherapy.

Materials

Records of all patients with a diagnosis of gastric lymphoma and which were treated in the National Institute of Oncology, between 1999 and 2006, were reviewed and patients fulfilling the following criteria were included in this study: histologically proven large-cell B lymphoma of the stomach; complete clinical information stage I/II disease according to the Musshoff staging; patients who received surgery followed by chemotherapy (group I) or chemotherapy alone (group II).

Results

This study included 82 patients who were treated for cancer in our Institute. All clinical and pathological features were similar between the two groups, except that patients of group-I had significantly more stage II disease (P = 0.023) than that of group II. Among the 52 patients who could be evaluated for response to chemotherapy, there were 45 who had complete response to treatment, 3 had partial response to the treatment and 4 had progressive disease. The projected 5-year relapse-free survival (RFS) and overall survival (OS) of group I were 86.69% (95% CI, 57.9 - 97.7%) and 90.0% (95% CI, 58.0 - 97.8%), respectively. And the projected 5-year relapse-free survival RFS and OS of group II were 86.67% (95% CI, 57.0 - 88.2%) and 93.33% (95% CI, 73.3 - 98.7%) respectively. There were no statistically significant differences in RFS (P = 0.485) and OS (P = 0.551) between the two groups.

Conclusion

Our data suggest that chemotherapy alone may be a reasonable alternative treatment for stage I/II gastric large-cell lymphoma but this result must be confirmed by prospective randomized clinical trials.     

Indicators of infestation, colonization and infection of Triatoma dimidiata (Latreille) (Hemiptera: Reduviidae) in Campeche, México

Triatoma dimidiata (Latreille) is considered to be one of the primary vectors of Chagas disease in Southern Mexico and Central America. The objective of the present study was to obtain ecological information on T. dimidiata in two rural communities of Campeche, Mexico, where the vector is poorly studied. Our work consisted of monthly samplings carried out during one-year time at three levels: sylvatic, peridomestic and intradomestic, in order to estimate the population abundance of this species and its rate of infection with Trypanosoma cruzi. Triatoma dimidiata was the unique vector of this disease collected in San Juan Bautista Sakcabchen (SJBS) and Crucero San Luis (CSL). The total of 145 individuals were captured in SJBS; from these, 26.9%, 20% and 53.1% were collected in the sylvatic, peridomestic and intradomestic area, respectively. In CSL captures yielded 108 individuals: 40.7% in the sylvatic area, 20.4% peridomestic and 38.9% intradomestic. We found no correlation between climatic variables and population abundance of T. dimidiata. Dataset obtained suggests that individuals from the sylvatic area exhibit a high rate of natural infection by T. cruzi, with monthly percentages up to 61.5% for SJBS and 50% for CSL. At the peri and intradomestic level, the reservoirs apparently play an important role in the transmission, as the seroprevalence in dogs was 61.5% y 65.4%, for SJBS y CSL, respectively. Based on these findings, it was concluded that inhabitants of both communities are at a high risk of Chagas disease infection.     

UV-Vis-NIR Laser Desorption/Ionization of Synthetic Polymers Assisted by Gold Nanospheres,Nanorods and Nanostars

The laser desorption/ionization (LDI) assisted by gold nanospheres, nanorods and nanostars has been investigated. Laser fluence thresholds for the appearance of cationized adducts of a polydispersed polyether standard (polyethylenglycol PEG600) have been determined at the near ultraviolet–visible–near infrared wavelengths delivered by a Nd:YAG laser (266, 355, 532, 1,064 nm). The results demonstrate the efficiency of surface plasmon excitation to assist laser desorption/ionizaton at laser wavelengths extending to the visible and near infrared, with advantages with respect to conventional LDI techniques using ultraviolet wavelengths. A close correlation is found between the optical absorbance of the nanoparticles and the LDI thresholds, although for the nanospheres plasmonic excitation in the visible appears to be more efficient than non-plasmonic excitation at shorter UV wavelengths. The recorded molecular weight distributions for the PEG600 standard show that the LDI process tends to be less efficient for the heavier components of the polymer mixture, presumably as a consequence of their stronger bonding to the nanoparticle substrate. The role of the coating agent of the nanoparticles in the observed LDI behavior is discussed.     

Nucleotide utilization requirements that render ClpB active as a chaperone

ClpB is a member of the AAA+ superfamily that forms a ring-shaped homohexamer. Each protomer contains two nucleotide binding domains arranged in two rings that hydrolyze ATP. We extend here previous studies on ClpB nucleotide utilization requirements by using an experimental approach that maximizes random incorporation of different subunits into the protein hexamer. Incorporation of one subunit unable to bind or hydrolyze ATP knocks down the chaperone activity, while the wt hexamer can accommodate two mutant subunits that hydrolyze ATP in only one protein ring. Four subunits seem to build the functional cooperative unit, provided that one of the protein rings contains active nucleotide binding sites.     

Relative Importance of Seed-Bank and Post-Disturbance Seed Dispersal on Early Gap Regeneration in a Colombian Amazon Forest

Early forest gap regeneration may be generated by postdisturbance seed rain and by seed, seedling or bud banks (i.e., resprouting). The relative importance of each process may depend on several factors (e.g., fruit/seed production, abundance and behavior of seed dispersers, gap characteristics, etc.). We experimentally compared the importance of seed-bank and seed-rain affecting early recruitment of seedlings in an Amazonian forest (Zafire Biological Station, Colombia), using soil transplants from forests to gaps and seed rain enclosures. We found that, during the 8-mo study, the seed-bank contributed with a larger number of individuals and species than seed-rain. The low seedling recruitment rates may be associated with reduced populations of animal seed-dispersers due to hunting and/or low levels of forest fruit production.     

Kinetics of oestrus ovis infection and activity of adult flies

Oestrus Ovis is a common sheep parasite in the Mediterranean region. This study was carried out in the Ebro River Valley near Zaragoza (northeast Spain) using tracer animals to describe the seasons when infestation is more likely. Based on that information and an analysis of the evolution of the parasite within the host, we suggest the most appropriate time for treatment. Adult instars appeared in May until November and there was a diapause beginning in October-November and as least until February, so it is suggested than sheep be treated with larvicide in December.