Bacteriocin-like substance (BLS) production in Aeromonas hydrophila water isolates

30 Aeromonas hydrophila water isolates were tested for bacteriocin-like substance (BLS) production using a target panel of closely related microorganisms and other Gram-positive and Gram-negative bacteria, including food-borne pathogens. A. hydrophila showed antibacterial activity against one or more indicator microorganisms, but the activity emerged only with non-phylogenetically related genera or species. In particular all A. hydrophila showed antibacterial activity against one or more of the tested Staphylococcus strains, five against Listeria spp. (Listeria seeligeri, Listeria welshimeri and Listeria ivanovii), and eight presented a weak antagonistic activity towards Streptococcus agalactiae and Lactobacillus spp. Inhibitory activity was not observed against the other Gram-positive (Listeria monocytogenes, Listeria innocua and Enterococcus spp.) and Gram-negative tested strains, including Aeromonas sobria, Aeromonas caviae and the same A. hydrophila, when used as indicator. Anti-staphylococcal activity was observed with a gradual increase of the inhibition zone during incubation and seemed to be influenced by A. hydrophila hemolytic expression. Extrachromosomal analysis showed the presence, in 70% of the strains, of one to five plasmids with molecular masses ranging from 2.1 to 41.5 MDa, but it was not possible to relate this result with BLS production.     

Ant Queen Egg-Marking Signals: Matching Deceptive Laboratory Simplicity with Natural Complexity

Background

Experiments under controlled laboratory conditions can produce decisive evidence for testing biological hypotheses, provided they are representative of the more complex natural conditions. However, whether this requirement is fulfilled is seldom tested explicitly. Here we provide a lab/field comparison to investigate the identity of an egg-marking signal of ant queens. Our study was based on ant workers resolving conflict over male production by destroying each other''s eggs, but leaving queen eggs unharmed. For this, the workers need a proximate cue to discriminate between the two egg types. Earlier correlative evidence indicated that, in the ant Pachycondyla inversa, the hydrocarbon 3,11-dimethylheptacosane (3,11-diMeC₂₇) is more abundant on the surface of queen-laid eggs.

Methodology

We first tested the hypothesis that 3,11-diMeC₂₇ functions as a queen egg-marking pheromone using laboratory-maintained colonies. We treated worker-laid eggs with synthetic 3,11-diMeC₂₇ and found that they were significantly more accepted than sham-treated worker-laid eggs. However, we repeated the experiment with freshly collected field colonies and observed no effect of treating worker-laid eggs with 3,11-diMeC₂₇, showing that this compound by itself is not the natural queen egg-marking pheromone. We subsequently investigated the overall differences of entire chemical profiles of eggs, and found that queen-laid eggs in field colonies are more distinct from worker-laid eggs than in lab colonies, have more variation in profiles, and have an excess of longer-chain hydrocarbons.

Conclusions

Our results suggest that queen egg-marking signals are significantly affected by transfer to the laboratory, and that this change is possibly connected to reduced queen fertility as predicted by honest signaling theory. This change is reflected in the worker egg policing response under field and laboratory conditions.     

Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes

Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.     

Caspase-1 levels in biological fluids from patients with multiple sclerosis and from patients with other neurological and non-neurological diseases

In multiple sclerosis (MS), pathological white matter damage in the central nervous system is sustained by immune-inflammatory response. Caspase-1 plays a pivotal role in immune-mediated inflammation, as it regulates the cellular export of IL-1beta and IL-18. We carried out a preliminary in vitro study of the kinetics of extracellular caspase-1 release. We then measured caspase-1 levels in paired serum and cerebrospinal fluid (CSF) samples of 75 MS patients, 15 healthy subjects, and patients with other neurological diseases. Paired synovial fluid and serum samples of patients with juvenile idiopathic arthritis, and paired sputum and serum samples of asthma patients were also studied. Mean serum caspase-1 concentrations did not differ between groups. Caspase-1 was detected in the CSF of patients with acute, but not stable, MS [7.5 +/- (SEM) 0.9 pg/ml; test's sensitivity, 56% and specificity, 100%]. Its levels correlated with pleocytosis. The highest mean caspase-1 levels were found in the arthritic synovial fluids (945.5 +/- 126.6 pg/ml, which correlated with erythrocyte sedimentation rate), and in the sputum samples (370.1 +/- 71.0 pg/ml, which correlated with the number of macrophages in the sputum). On condition that caspase-1 is determined in the fluids pertaining to the disease-specific inflammatory sites, its level is a reliable marker of ongoing immune-inflammatory response. The enzyme measurement in CSF can also help define state-trait in MS.     

Matrix metalloproteinases 9 and 2 are necessary for the migration of Langerhans cells and dermal dendritic cells from human and murine skin

Dendritic cells migrate from the skin to the draining lymph nodes. They transport immunogenic MHC-peptide complexes, present them to Ag-specific T cells in the T areas, and thus generate immunity. Migrating dendritic cells encounter physical obstacles, such as basement membranes and collagen meshwork. Prior work has revealed that matrix metalloproteinase-9 (MMP-9) contributes to mouse Langerhans cell migration. In this study, we use mouse and human skin explant culture models to further study the role of MMPs in the migration and maturation of skin dendritic cells. We found that MMP-2 and MMP-9 are expressed on the surface of dendritic cells from the skin, but not from other sources. They are also expressed in migrating Langerhans cells in situ. The migration of both Langerhans cells and dermal dendritic cells is inhibited by a broad spectrum inhibitor of MMPs (BB-3103), by Abs to MMP-9 and -2, and by the natural tissue inhibitors of metalloproteinases (TIMP), TIMP-1 and TIMP-2. Inhibition by anti-MMP-2 and TIMP-2 define a functional role for MMP-2 in addition to the previously described function of MMP-9. The importance of MMP-9 was emphasized using MMP-9-deficient mice in which Langerhans cell migration from skin explants was strikingly reduced. However, MMP-9 was only required for Langerhans cell migration and not maturation, since nonmigrating Langerhans cells isolated from the epidermis matured normally with regard to morphology, phenotype, and T cell stimulatory function. These data underscore the importance of MMPs, and they may be of relevance for therapeutically regulating dendritic cell migration in clinical vaccination approaches.     

Expression of pituitary adenylate cyclase-activating polypeptide and PACAP type 1 receptor in the rat gastric and colonic myenteric neurons

Pituitary adenylate cyclase-activating polypeptide (PACAP) is known to regulate gastric acid secretion and intestinal motility. In the present study, the pattern of distribution of PACAP and PACAP type 1 receptor (PAC1) immunoreactivities were examined in the rat stomach and distal colon using a specific polyclonal antibody raised against rat/human PAC1. Western blot of the membrane preparations of NIH/3T3 cells transfected with the human PAC1 obtained by using rabbit polyclonal anti-PAC1 antibody showed a protein band with a molecular mass of approximately 50 kDa. NIH/3T3 cells transfected with the human PAC1 and incubated with the anti-PAC1 antibody displayed surface cell-type immunoreactivity, which was internalized following ligand exposure. In gastric or colonic longitudinal muscle/myenteric plexus (LMMP) whole mount preparations as well as cryostat sections, PACAP immunoreactivity was observed in cell bodies within the myenteric ganglia and nerve fibers in the muscle layers and mucosa. PAC1 immunoreactivity was confined mainly on the surface of the nerve cells. PACAP and PAC1 immunoreactivities showed a similar pattern of distribution in gastric and colonic tissues. Adjacent sections or LMMP whole mount preparations labeled with protein gene product 9.5 (PGP 9.5) revealed the neuronal identity of myenteric cells bearing PAC1. The neuronal localization of PACAP and PAC1 receptors supports their role in the neural regulation of gastric acid secretion and gastrointestinal motor function.     

Personal best time and training volume, not anthropometry, is related to race performance in the 'Swiss Bike Masters' mountain bike ultramarathon

We investigated in 73 male ultraendurance mountain bikers, with (mean and SD) age 39.1 (8.6) years, weight 74.4 (8.3) kg, height 1.78 (0.07) m, and a body mass index of 23.3 (1.9) kg·m?2, whether variables of anthropometry, training, or prerace experience were associated with race time using bi and multivariate analysis. Our investigation was conducted at the "Swiss Bike Masters," which covers a distance of 120 km and an altitude of 5,000 m. In the bivariate analysis, body mass index (r = 0.29), circumference of upper arm (r = 0.28), sum of upper body skinfolds (r = 0.38), sum of lower body skinfolds (r = 0.25), sum of 8 skinfolds (r = 0.36), percent body fat (r = 0.41), total cycling kilometers per year (r = -0.47), yearly volume in both mountain bike (r = -0.33) and road cycling (r = -0.52), number of training units per week (r = -0.48), distance per unit in road cycling (r = -0.33), average speed during training in road cycling (r = -0.33), and personal best time in the "Swiss Bike Masters"(r = 0.67) were related to race time. In the multiple linear regression analysis, personal best time in the "Swiss Bike Masters" (p = 0.000), total yearly cycling kilometers (p = 0.004), and yearly training kilometers in road cycling (p = 0.017) were related to race time. When the personal best time was the dependent variable in a separate regression model, total yearly cycling kilometers (p = 0.002) remained the single predictor variable. We concluded that finishing a particular mountain bike ultramarathon does not seem to require a special anthropometry but rather a specific skill and experience for this selective kind of race coupled with a high training volume. For practical use, we concluded that successful athletes in a mountain bike ultramarathon, in a special environment and using sophisticated equipment, need prerace experience coupled with high training volume, rather than any special anthropometry.     

Chimpanzees’ constructional praxis (Pan paniscus, P. troglodytes)

This study investigated chimpanzees spontaneous spatial constructions with objects and especially their ability to repeat inter-object spatial relations, which is basic to understanding spatial relations at a higher level than perception or recognition. Subjects were six chimpanzees—four chimpanzees and two bonobos—aged 6–21 years, all raised in a human environment from an early age. Only minor species differences, but considerable individual differences were found. The effect of different object samples was assessed through a comparison with a previous study. A common overall chimpanzee pattern was also found. Chimpanzees repeated different types of inter-object spatial relations such as insertion (I), or vertical (V), or next-to (H) relations. However chimpanzees repeated I or V relations with more advanced procedures than when repeating H relations. Moreover, chimpanzees never repeated combined HV relations. Compared with children, chimpanzees showed a specific difficulty in repeating H relations. Repeating H relations is crucial for representing and understanding multiple reciprocal spatial relations between detached elements and for coordinating independent positions in space. Therefore, the chimpanzees difficulty indicates a fundamental difference in constructive space in comparison to humans. The findings are discussed in relation to issues of spatial cognition and tool use.