Anorectal Human Papillomavirus: Current Concepts

Increased anorectal human papillomavirus (HPV) infection is related to the recent trends in sexual behavior in both homosexual and heterosexual groups and prevalence of infection with human immunodeficiency virus (HIV). Clinical presentation and natural history depend on the serotype involved. HPV 6 and 11 are found in the benign wart. Local control can be achieved with a wide selection of surgical and topical techniques. HPV 16, 18, and 31 are found in dysplastic lesions and have the potential to progress to invasive anal squamous cell carcinoma. Recognition and early management of dysplastic lesions is crucial to prevent the morbidity and mortality associated with anal cancer. While low-grade lesions can be closely observed, high-grade lesions should be eradicated. Different strategies can be used to eradicate the disease while preserving anorectal function. Studies on the efficacy of vaccination on anorectal HPV showed promising results in select population groups and led to the recent expansion of current vaccination recommendations.     

Coincidence of biophoton emission by wheat seedlings during simultaneous, transcontinental germination tests

Measurements of spontaneous ultra-weak light (biophoton) emission from native Brazilian and German wheat seedlings in three simultaneous series of germination tests are presented, two run in Germany and one in Brazil. Seedlings in both countries presented semi-circadian rhythms of emission that were in accordance with the local lunisolar gravimetric tidal acceleration, as did seeds which had been transported from Brazil to Germany. The simultaneity of the photon emission patterns in all tests argues for the lunisolar tide and its rhythmic variations as regulators of the natural rhythm of photon emission. However, seedlings from seed samples transported from Brazil to Germany showed, in addition, a temporary disturbance within the emission periodicity which may indicate a possible short-term acclimatization to the new location.     

Owning an Overweight or Underweight Body: Distinguishing the Physical,Experienced and Virtual Body

Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant''s experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups.     

Structure and Haem-Distal Site Plasticity in Methanosarcina acetivorans Protoglobin

Protoglobin from Methanosarcina acetivorans C2A (MaPgb), a strictly anaerobic methanogenic Archaea, is a dimeric haem-protein whose biological role is still unknown. As other globins, protoglobin can bind O₂, CO and NO reversibly in vitro, but it displays specific functional and structural properties within members of the hemoglobin superfamily. CO binding to and dissociation from the haem occurs through biphasic kinetics, which arise from binding to (and dissociation from) two distinct tertiary states in a ligation-dependent equilibrium. From the structural viewpoint, protoglobin-specific loops and a N-terminal extension of 20 residues completely bury the haem within the protein matrix. Thus, access of small ligand molecules to the haem is granted by two apolar tunnels, not common to other globins, which reach the haem distal site from locations at the B/G and B/E helix interfaces. Here, the roles played by residues Trp(60)B9, Tyr(61)B10 and Phe(93)E11 in ligand recognition and stabilization are analyzed, through crystallographic investigations on the ferric protein and on selected mutants. Specifically, protein structures are reported for protoglobin complexes with cyanide, with azide (also in the presence of Xenon), and with more bulky ligands, such as imidazole and nicotinamide. Values of the rate constant for cyanide dissociation from ferric MaPgb-cyanide complexes have been correlated to hydrogen bonds provided by Trp(60)B9 and Tyr(61)B10 that stabilize the haem-Fe(III)-bound cyanide. We show that protoglobin can strikingly reshape, in a ligand-dependent way, the haem distal site, where Phe(93)E11 acts as ligand sensor and controls accessibility to the haem through the tunnel system by modifying the conformation of Trp(60)B9.     

Distinct proliferative T cell clonotypes are generated in response to a murine retrovirus-induced syngeneic T cell leukemia: viral gp70 antigen-specific MT4+ clones and Lyt-2+ cytolytic clones which recognize a tumor-specific cell surface antigen

After immunization of B6 mice with the syngeneic retrovirus-induced T cell leukemia/lymphoma FBL-3, two major tumor-specific proliferative T cell clonotypes were derived. T cell clones derived from long-term lines propagated by in vitro culture with irradiated tumor cells and syngeneic spleen cells were exclusively of the Lyt-2+ phenotype. Such clones were cytolytic, retained their proliferative phenotype indefinitely when expanded by repeated cycles of reactivation and rest, and recognized a tumor-specific cell surface antigen in association with class I MHC molecules. This tumor cell antigen was not present on nontransformed virus-infected cells. Class II MHC-restricted MT4+ clones specific for the viral antigen gp70 were derived from lymph node T cells of FBL-3 tumor-immune mice only by in vitro culture with purified Friend virus in the presence of syngeneic splenic APC. Once derived, however, such clones could be stimulated in the presence of FBL-3 tumor cells and syngeneic spleen cells, demonstrating the reprocessing of tumor-derived gp70 antigen by APC in the spleen cell population. In contrast, no reprocessing of the tumor cell surface antigen by splenic APC for presentation to the class I MHC-restricted T cell clones could be demonstrated. Evidence is presented that FBL-3 T leukemia/lymphoma cells function as APC for Lyt-2+ class I MHC-restricted clones, and that no concomitant recognition of Ia molecules is required to activate these clones. Both Lyt-2+ and MT4+ clones were induced to proliferate in the presence of exogenous IL2 alone, but this stimulus failed to result in significant release of immune interferon. In contrast, antigen stimulation of both clones resulted in proliferation as well as significant immune interferon release. Immune interferon production is not required for the generation of MHC-restricted cell-mediated cytolytic function.     

Time–activity budget of greater rheas (Rhea americana, Aves) on a human-disturbed area: the role of habitat, time of the day, season and group size

The aim of this study was to evaluate activity–time budget, habitat use and how seasonality and group size influence the expression of greater rhea behaviours. Greater rheas are threatened South American birds; habitat loss, predation and hunting are the main factors responsible for population declines. The study was conducted in farmlands within a matrix of commercial Eucalyptus plantation and remnants of natural habitats of cerrado vegetation (savannah-like) in southeastern Brazil. Rhea groups were located visually in different habitats visited monthly from January 2004 to December 2005. Time spent searching greater rheas in each habitat was equally distributed. Data were collected using scan sampling with instantaneous recording of behaviours every minute. The time–activity budget of greater rheas was influenced by habitat structure, time of the day, season and group size. Rheas spent more time in open areas than in forested areas (p < 0.001). Vigilance behaviours were more displayed in forested areas, in the dry season and by solitary and small groups of birds. Resting behaviours occurred more often in open lands and within groups with more than three rheas. Food availability, good visibility and low human presence are the possible factors for the preference of greater rheas for pasturelands. The results support the resource availability hypothesis, where it is expected that habitats with a higher food availability will be more used by the animals, group size hypothesis, where the scarcity of resources will lead to smaller groups of animals and that forestry modifies greater rheas habitat use and behaviours.     

<Emphasis Type="Italic">Crassostrea gigas</Emphasis> in natural oyster banks in southern Brazil

We report on the invasion of Brazil by the Pacific oyster Crassostrea gigas, and discuss the likely routes of invasion. Because this phenotypically diverse oyster sometimes resembles the native species C. brasiliana and C. rhizophorae, its invasion went unnoticed until it was detected through the analysis of DNA sequences for ribosomal 16S and the ribosomal second internal transcribed spacer. C. gigas was found amongst the native species in oyster banks up to 100 km south of oyster farms in South Brazil. Under most circumstances, water temperatures in the coastal southerly Brazil current would be too high to allow for the establishment of stable populations of C. gigas, but the production of spat in oyster farm laboratories has probably selected for resistance to warmer temperatures, which would promote invasion by C. gigas.     

Persistence with Chytridiomycosis Does Not Assure Survival of Direct-developing Frogs

The chytrid fungus, Batrachochytrium dendrobatidis (Bd) has been linked to extinction and decline of numerous amphibians. We studied the population-level effects of Bd in two post-decline anuran species, Eleutherodactylus coqui and E. portoricensis, at El Yunque National Forest, Puerto Rico. Data on amphibian abundance was updated to report long-term population trends. Mark–recapture data was used to monitor Bd-infection status and estimate survival probabilities of infected versus uninfected adults. Prevalence of Bd (number of infected/total sampled) and individual infection level (number of zoospores) were compared among age classes at Palo Colorado Forest (661 m) and Elfin Forest (850 m). Results revealed that both species continued to decrease in Palo Colorado Forest, while in the Elfin Forest, E. portoricensis recuperated from drastic declines. Age class, season, and locality significantly predicted zoospore load. Age was also significantly associated with high zoospores loads among Bd-positive frogs, and the prevalence of Bd was higher in juveniles than adults in all populations studied. We suggest that early age represents a critical life stage in the survival of direct-developing frogs infected by this fungus. Survival probability was always higher for uninfected frogs, but recapture rates of infected versus uninfected adults were significantly different only in Palo Colorado, alerting that the negative effect of Bd infection under enzootic conditions is greater at mid-elevations. This work contributes to our understanding of how direct-developing amphibians persist with Bd, pointing to critical life stages and synergistic interactions that may induce fluctuations and/or declines in the wild.     

Thermostable lipolytic enzymes production in batch and continuous cultures of Thermus thermophilus HB27

Several studies in laboratory-scale bioreactors are undertaken in order to verify the beneficial effect of thermal spring water in the culture medium of Thermus thermophilus HB27. Two bioreactor configurations, stirred tank and airlift, are investigated to determine the most suitable one to develop a continuous process. Water mineral composition affects the lipolytic enzyme secretion and growth of T. thermophilus HB27 in both bioreactor configurations. Furthermore, the lipolytic activity is strongly enhanced when stirred tank bioreactor is used. Moreover, operation in a stirred tank at an agitation rate of 650 rpm leads to the highest total lipolytic activity (intra- and extracellular enzyme) around 280 U/L after 32 h. Continuous cultures operating in the optimised conditions determined in batch cultures are carried out. It is noticeable that the stirred tank bioreactor was able to operate in a continuous flow mode without operational problems. In addition, the lipolytic activity obtained is about 2-fold higher than that attained in batch cultures.