Floral Scent Chemistry and Pollinators of a Sexually Dimorphic Neotropical Orchid.

Catasetum is a speciose Neotropical orchid genus of which male and female flowers emit scents acting both as attractant and reward for their exclusive pollinators, male orchid bees (Euglossini: Apidae). In Catasetum, it is well known that flowers display a remarkably morphological sexual dimorphism. However, it remains poorly investigated whether this is also true for floral scents. Here, we investigated the pollination ecology and floral scent traits (chemistry and total emission) of C. maranhense, a species endemic to the Brazilian N/NE region. Males of Euglossa securigera are the only pollinators of C. maranhense. The floral scent of C. maranhense is composed of 29 volatile compounds, with eucalyptol, indole, (E)-Methyl p-methoxycinnamate, and (Z)-Methyl p-methoxycinnamate accounting for more than 80% of the scent bouquet. No sexual dimorphism was detected in any of the traits investigated. We discuss the ecological and evolutionary significance of our findings to Catasetum species and other unisexual perfume plants.

Forest Matrix Fosters High Similarity in Bee Composition Occurring on Isolated Outcrops Within Amazon Biome.

Most studies analyze fragmentation due to habitat loss caused by anthropogenic activities and few of them analyzed fragmentation on naturally fragmented areas. In the Eastern Amazon, it is possible to find areas naturally open and surrounded by pristine forest. Understanding how species respond to isolation in these areas is an important challenge for decision-making processes aiming conservation and restoration. Using standardized methods of bee collection (entomological nets, bait trap, pan trap, and nest trap), the objective of this study was to analyze the composition and diversity of bees occurring on six isolated outcrops located in two protected areas within Amazon biome. More specifically, we tested 1) if the dissimilarity in bee species composition is explained by the isolation of outcrops and 2) if bee richness, abundance, and Shannon diversity can be explained by the outcrop size. We found 118 species, with the Meliponini and Euglossini (Hymenoptera: Apidae) tribes representing the highest number of species. The similarity in species composition across all outcrops is high and is not explained by the isolation. In addition, the richness, abundance, and Shannon diversity are not explained by outcrop size. Forest does not seem to be a barrier to bee movement, and although most species probably nest in the forests, they use the highly diverse plants of the outcrops as a complementary food source.

Interferon-inducible guanylate binding protein (GBP)-2: a novel p53-regulated tumor marker in esophageal squamous cell carcinomas.

TP53 mutations are common in esophageal squamous cell carcinomas (SCC). To identify biological markers of possible relevance in esophageal SCC, we (i) searched for genes expressed in a p53-dependent manner in TE-1, an esophageal SCC cell line expressing the temperature-sensitive TP53 mutant V272M, and (ii) investigated the expression of one of those genes, the interferon-inducible Guanylate Binding Protein 2 (GBP-2), in esophageal SCC tissues. Clontech Human Cancer 1.2 arrays containing 1,176 human cancer gene-related sequences were used to identify differentially expressed genes in TE-1 cells at permissive (32 degrees C) and nonpermissive (37 degrees C) temperatures. The expression of GBP-2 and IRF-1, its main transcriptional regulator, was analyzed by immunohistochemistry in a retrospective series of 41 esophageal SCC cases with a clear transition zone from noncancer, apparently normal epithelium to invasive cancer. The expression of the GBP-2 gene is consistently increased in TE-1 at 32 degrees C in a p53-dependent manner, as confirmed by inhibition of p53 expression by RNA interference. Increase in GBP-2 is accompanied by an increase in protein levels of IRF-1, the main transcriptional regulator of GBP-2, and in the formation of complexes between p53 and IRF-1. GBP-2 expression is significantly higher in esophageal SCC than in adjacent normal epithelium (p<0.01), in which GBP-2 staining is limited to the basal layer. Our results suggest that p53 up-regulates GBP-2 by cooperating with IRF-1. The association of GBP-2 expression with proliferative squamous cells suggests that GBP-2 may represent a marker of interest in esophageal SCC.

Lymph Nodes Number in Surgical Specimen Modifies Prognosisin Advanced Stage Gastric Cancer Patients– Study of the Will-Rogers Phenomenon

Background: The AJCC 2002 staging system recommends the study of at least 15 lymph nodes in the surgical specimen. Thisnumber varies and sometimes it is not achieved since it is influenced by surgeons, pathologists and patients and may modifythe patient’s staging and survival. Methods: This is an observational study of 201 patients with gastric cancer submitted tosurgery in the period of January 1997 to December 2001, and followed-up until July 2003 in the Brazilian National CancerInstitute. Data related to surgeon and pathologist productivity as well as survival were analyzed. Results: All patients that haveundergone D2 lymphadenectomy had more than 15 lymph nodes. The factors related to varied number of lymph nodes were:surgeon (31.5±9.3 to 43.8 ±16.8); surgical procedure (total gastrectomy, 41.4 ±15.5); extended resection (40.8 ±15.9);pN3 and stage IV (55.1 ±15.8). Multivariate analysis showed the surgeon as an independent variable (p=0,02). The morelymph nodes studied, the more nodal metastasis found (p=0.01), but this fact has been significant only in pT3 patients(p=0.007). The variables related to survival have been surgical procedure, resection of another organ, site of the tumor; pT andpN. The independent variables have been pT (p=0,01) and pN (p=0,004). Conclusion: The surgeon’s technique is the mainfactor related to number of lymph nodes in the surgical specimen and for accurate staging of pT3 patients over 30 lymph nodesarenecessary.