Human CD38 and its ligand CD31 define a unique lamina propria T lymphocyte signaling pathway.

CD38, a nonlineage-restricted surface glycoprotein, is an ecto-enzyme (ADP ribosyl cyclase/cADPR hydrolase/EC 3.2.2.6) that regulates cytoplasmic Ca2+ and cell-cell interactions. The molecule also delivers trans-membrane signals, despite a structural ineptitude to the scope. To reconcile these issues in a unitarian model, we compared the effects of CD38 signaling in circulating and residential T lymphocytes, the latter represented by those colonizing the intestinal lamina propria. Results are as follows: 1) LP T cells express an enzymatically active form of CD38, characterized by a modified ratio between cyclase and hydrolase functions; 2) LP T cells do not mobilize Ca2+ upon CD38 ligation, as seen in PB T cells (this condition is due to a lack in activation of PLC- g, constantly observed in PB T lymphocytes); 3) The early steps of CD38 signaling involve activation of lck, syk, and LAT; 4) Late events include synthesis and release of IL-2, IL-4, IL-5, IL-10, IFN-g and GM-CSF; 5) The uniqueness of the CD38 pathway in LP T cells is not caused by impaired interactions with the CD31 ligand. The differences observed concern the signaling machinery that CD38 exploits for its own use and not the interplay with its ligand.     

Carrion flies of forensic interest: a study of seasonal community composition and succession in Lisbon,Portugal

Information on Diptera community, seasonality and successional patterns in every geographical region is fundamental for the use of flies as forensic indicators of time of death. In order to obtain these data from the Lisbon area (Portugal), experiments were conducted during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognized during the decomposition process. The stages, besides visually defined, could be separated taking into account the occurrence and abundance of the specific groups of Diptera collected. In general, the bloated stage recorded higher abundance and species‐richness values. Seventy‐one species were identified, belonging to 39 families, in a total of 20 144 adult Diptera collected. Autumn yielded the highest values of species richness, whereas winter had the lowest. In all seasons of the year, Calliphoridae was the dominant family; Muscidae and Fanniidae were very abundant as well. Calliphora vicina Robineau‐Desvoidy, Calliphora vomitoria (Linnaeus), Chrysomya albiceps (Wiedemann), Lucilia ampullacea Villeneuve, Lucilia caesar (Linnaeus), Lucilia sericata (Meigen) (Calliphoridae), Hydrotaea ignava (Harris), Muscina prolapsa (Harris), Synthesiomyia nudiseta (van der Wulp) (Muscidae), Piophila megastigmata McAlpine, Stearibia nigriceps (Meigen) (Piophilidae) and Nemopoda nitidula (Fallén) (Sepsidae) were revealed to be very important members of the Diptera community collected. The necrophagous behaviour, demonstrated by their immatures, using carrion as a food source makes them useful forensic indicator species. Also of relevance is the presence of Chrysomya megacephala (Fabricius), S. nudiseta and P. megastigmata, foreign species established in the local carrion communities. This study also marks the first record of S. nudiseta in Portugal.     

Ultrastructural Studies of Spermiogenesis of Conocephalus saltator (Saussure)

The acrosome of the spermatozoa is the organelle involved in its penetration through the ova membranes during the fertilization process. Several features of this process are considered to be related to the fertilization events e.g. some substance coats outside the membrane. During the maturation process the spermatozoa of Conocephalus saltator develop a coat of tubules and filaments which overly some membrane regions in a specific array. The mature spermatozoa are seen to adhere in these regions and form threads of 20 cells long and five to six wide. It is suggested that the external coat plays a role in this 'sticking' phenomenon.     

Total sleep deprivation does not significantly degrade semantic encoding

ABSTRACT

Sleep deprivation impairs performance on cognitive tasks, but it is unclear which cognitive processes it degrades. We administered a semantic matching task with variable stimulus onset asynchrony (SOA) and both speeded and self-paced trial blocks. The task was administered at the baseline and 24 hours later after 30.8 hours of total sleep deprivation (TSD) or matching well-rested control. After sleep deprivation, the 20% slowest response times (RTs) were significantly increased. However, the semantic encoding time component of the RTs remained at baseline level. Thus, the performance impairment induced by sleep deprivation on this task occurred in cognitive processes downstream of semantic encoding.