Natural mortality factors acting on citrus leafminer, Phyllocnistis citrella, in lime orchards in South Florida

Seasonal mortality of the citrusleafminer, Phyllocnistis citrellaStainton, was studied from 1994 through 1998 in`Tahiti' lime, Citrus aurantifolia (Christm.) Swingle,in Homestead, Florida. Survival of eachdevelopmental host stage and the proportionattacked by indigenous and introduced naturalenemies were determined. Before the recovery ofthe introduced parasitoid, Ageniaspiscitricola Logvinovskaya, in 1995, thethird-instar host had the highest averageproportion of parasitized individuals (0.14)followed by the prepupa (0.11) while the firstinstar had the lowest proportion parasitized(0.02). After the first recovery andestablishment of A. citricola, theproportion of pupae parasitized increased to0.56 followed by the prepupa (0.14) and thethird instar (0.11). Before the introduction ofA. citricola, the highest proportion ofhosts killed by predation was observed insecond instar (0.17) and third instar (0.15).After the establishment of the introducedspecies, the proportion of dead individuals dueto predation was greater for second instar(0.31) and third instar (0.21) larvae.Mortality caused by indigenous natural enemieswas significantly correlated with increases ofP. citrella density. Parasitism ofP. citrella by the exotic parasitoid,A. citricola, correlated less well to hostdensity over the season (r² = 0.12) thandid mortality caused by indigenous naturalenemies (r² = 0.76). Moreover, a higherpercent mortality in population of P. citrellawas obtained from predation by theindigenous natural enemies than the introducedparasitoid as shown in the mortality estimatesfrom 1995 to 1998.     

An introduction to provisional stenting

Provisional or conditional stenting should be defined as the use of stents limited to those conditions and cases in which the operator, despite an aggressive balloon angioplasty technique with large balloons and high pressure, has been unable to obtain a result that ensures optimal chances of early and late patency. The paramount issue is how to discriminate the patients with optimal results after balloon angioplasty for whom additional stent implantation is unlikely to improve or may even worsen long-term outcome. The better results of elective stent implantation in the OPUS study suggest that visual assessment of the PTCA result is not sufficient to detect lesions with suboptimal lumen gain after PTCA. The addition of physiologic parameters (Doppler flow velocity measurements, fractional flow reserve) has improved the results of the provisional stent group, with the best outcome observed when complex lesions and multivessel treatment were included in these studies (FROST, DESTINI). Intravascular ultrasound, although more expensive and time-consuming, has the additional advantage to guide the dilatation strategy.     

Characterization of CD4+ T cell responses during natural infection with Salmonella typhimurium

CD4+ T cells are important for resistance to infection with Salmonella typhimurium. However, the Ag specificity of this T cell response is unknown. Here, we demonstrate that a significant fraction of Salmonella-specific CD4+ T cells respond to the flagellar filament protein, FliC, and that this Ag has the capacity to protect naive mice from lethal Salmonella infection. To characterize this Ag-specific response further, we generated FliC-specific CD4+ T cell clones from mice that had resolved infection with an attenuated strain of Salmonella. These clones were found to respond to an epitope from a constant region of FliC, enabling them to cross-react with flagellar proteins expressed by a number of distinct Salmonella serovars.     

The Influence of Reactive Oxygen Species on the Adhesion of Pancreatic Carcinoma Cells to the Peritoneum

Postoperative peritoneal carcinomatosis is a significant clinical problem after “curative” resection of pancreatic carcinoma. Preoperative surgical trauma activates a cascade of peritoneal defense mechanisms responsible for postoperative intra-abdominal tumor recurrence. Reactive oxygen species (ROS) play a pivotal role in this postoperative inflammatory reaction. This study explores the influence of ROS on adhesion of human pancreatic carcinoma cells to human mesothelial cells. Furthermore this study explores the influence of ROS on the presentation of adhesion molecules on Panc-1 and mesothelial cells. ROS were produced using the enzymatic reaction of xanthine with xanthine oxidase (X/XO). A reproducible in vitro assay to study adhesion of human Panc-1 carcinoma tumor cells to a mesothelial cell monolayer of primary human mesothelial cells was used. Mesothelial monolayers were incubated with ROS produced prior to adhesion of the tumor cells. Incubation of the mesothelial cells with X/XO resulted in a significant increase (69.5%) in adhesion of Panc-1 in all patients. SOD/catalase, anti-oxidants, could reduce this increase by 56.7%. ROS significantly influenced the expression of the adhesion molecules ICAM-1, VCAM-1 and CD44h on mesothelial cells, but did not influence adhesion molecule expression on Panc-1. The ROS released during the post-operative inflammatory reaction may play an important role in the adhesion of pancreatic tumor cells to the mesothelium-possibly by influencing adhesion molecule expression on mesothelial cells. Therefore ROS can partly be responsible for the enhanced post-operative intra-abdominal tumor recurrence.Key words: reactive oxygen species, mesothelium, Panc-1     

Effects of Infection by Belonolaimus longicaudatus on Rooting Dynamics among St. Augustinegrass and Bermudagrass Genotypes

Understanding rooting dynamics using the minirhizotron technique is useful for cultivar selection and to quantify nematode damage to roots. A 2-yr microplot study including five bermudagrass (‘Tifway’, Belonolaimus longicaudatus susceptible; two commercial cultivars [TifSport and Celebration] and two genotypes [‘BA132’ and ‘PI 291590’], which have been reported to be tolerant to B. longicaudatus) and two St. Augustinegrass (‘FX 313’, susceptible, and ‘Floratam’ that was reported as tolerant to B. longicaudatus) genotypes in a 5 x 2 and 2 x 2 factorial design with four replications, respectively, was initiated in 2012. Two treatments included were uninoculated and B. longicaudatus inoculated. In situ root images were captured each month using a minirhizotron camera system from April to September of 2013 and 2014. Mixed models analysis and comparison of least squares means indicated significant differences in root parameters studied across the genotypes and soil depths of both grass species. ‘Celebration’, ‘TifSport’ and ‘PI 291590’ bermudagrass, and ‘Floratam’ St. Augustinegrass had significantly different root parameters compared to the corresponding susceptible genotypes (P ≤ 0.05). Only ‘TifSport’ had no significant root loss when infested with B. longicaudatus compared to non-infested. ‘Celebration’ and ‘PI 291590’ had significant root loss but retained significantly greater root densities than ‘Tifway’ in B. longicaudatus-infested conditions (P ≤ 0.05). Root lengths were greater at the 0 to 5 cm depth followed by 5 to 10 and 10 to 15 cm of vertical soil depth for both grass species (P ≤ 0.05). ‘Celebration’, ‘TifSport’, and ‘PI 291590’ had better root vigor against B. longicaudatus compared to Tifway.     

Creatine kinase isoenzyme activity during and after an ultra-distance (200 km) run

It is commonly assumed that creatine kinase (CK) activity in plasma is related to the state of an inflammatory response at 24-48 h, and also it has shown biphasic patterns after a marathon run. No information is available on CK isoenzymes after an ultra-marathon run. The purpose of the present study is to examine the CK isoenzymes after a 200 km ultra-marathon run and during the subsequent recovery. Blood samples were obtained during registration 1 2 h before the 200-km race and during the race at 100 km, 150 km and at the end of 200 km, as well as after a 24 h period of recovery. Thirty-two male ultra-distance runners participated in the study. Serum CPK showed a marked increase throughout the race and 24 h recovery period (p < 0.001). Serum CK during the race occurs mostly in the CK-MM isoform and only minutely in the CK-MB isoform and is unchanged in the CK-BB isoform. High-sensitivity C-reactive protein (hs-CRP), oestradiol, AST and ALT increased significantly from the pre-race value at 100 km and a further increase took place by the end of the 200 km run. The results of our study demonstrate a different release pattern of creatine kinase after an ultra-distance (200 km) run compared to the studies of marathon running and intense eccentric exercise, and changes in several biomarkers, indicative of muscle damage during the race, were much more pronounced during the latter half (100–200 km) of the race. However, the increases in plasma concentration of muscle enzymes may reflect not only structural damage, but also their rate of clearance.     

A MademoiseLLE domain binding platform links the key RNA transporter to endosomes

Spatiotemporal expression can be achieved by transport and translation of mRNAs at defined subcellular sites. An emerging mechanism mediating mRNA trafficking is microtubule-dependent co-transport on shuttling endosomes. Although progress has been made in identifying various components of the endosomal mRNA transport machinery, a mechanistic understanding of how these RNA-binding proteins are connected to endosomes is still lacking. Here, we demonstrate that a flexible MademoiseLLE (MLLE) domain platform within RNA-binding protein Rrm4 of Ustilago maydis is crucial for endosomal attachment. Our structure/function analysis uncovered three MLLE domains at the C-terminus of Rrm4 with a functionally defined hierarchy. MLLE3 recognises two PAM2-like sequences of the adaptor protein Upa1 and is essential for endosomal shuttling of Rrm4. MLLE1 and MLLE2 are most likely accessory domains exhibiting a variable binding mode for interaction with currently unknown partners. Thus, endosomal attachment of the mRNA transporter is orchestrated by a sophisticated MLLE domain binding platform.     

T cell clonal conditioning: a phase occurring early after antigen presentation but before clonal expansion is impacted by Toll-like receptor stimulation

After in vivo immunization, Ag-specific T cells disappear from circulation and become sequestered in lymphoid tissue where they encounter Ag presented by dendritic cells. In the same site and just after Ag presentation, they "disappear" a second time and we investigated this process. Using a mouse model of T cell deletion (without Toll-like receptor (TLR) stimulation) vs survival (with TLR stimulation), Ag-specific T cells indeed became undetectable by flow cytometry, however were readily detected by immunohistochemistry. Thus, whether or not the activated T cells were destined to delete or survive, they were difficult to extract from lymphoid tissue and did not disappear but in fact were abundantly present. Nevertheless, profound differences were observed during this time period when tolerizing conditions were compared with immunizing conditions. TLR stimulation induced an increase in CD25 expression, acquisition of surface MHC class II, and abnormally high increases in forward and side scatter of the peptide-specific T cells. Using a modified adoptive transfer approach, we demonstrated by flow cytometry that in the presence of TLR stimulation the Ag-specific T cells were tightly coupled to dendritic cells, explaining the unusual increases in size and granularity. Ultimately, these events induced the specific T cells to differentiate into memory cells. We postulate that this is a stage where T cells are either conditioned to survive or to delete depending upon the activation status of the innate immune system.     

Meeting report: a symposium on the evolution of common molecular pathways underlying innate immunity

The University of California, Davis hosted a symposium on innate immunity in January 2012. Professors Bruce Beutler, Jules Hoffmann, Luke O'Neill and Pamela Ronald discussed their research on mechanisms that multicellular organisms use to recognize microbes.