Understanding the Technical-Scientific Gaps of Underutilized Tropical Species: The Case of Bactris gasipaes Kunth

The extraction and commercialization of palm hearts is the most profitable activity involving the peach palm (Bactris gasipaes), while consumption of its fruits is limited to Amazonian communities. The excessive attention paid to the implementation of germplasm banks contributed to the lack of development of high-performance varieties, limiting the production and consumption of peach palm fruits and by-products. In addition, with the fragmentation of the Amazonian rainforest, wild populations are in danger of extinction. The species domestication, initiated by Native Amazonians, generated a large variety of peach palm populations, as evidenced by the diversity in fruit sizes and quality. Some advances in agronomic traits also took place. However, more research needs to be conducted to understand the implications of climatic changes on plant physiological performance. Indeed, the key point is that the exploitation of the full potential of B. gasipaes has not been completely exploited. Therefore, understanding the state-of-the-art research on the peach palm with a focus on its underutilized resources is essential for expanding plantations and, consequently, promoting the market expansion of the peach palm as a fruit crop.

Purification and characterization of a lectin of the Swartzieae Legume Taxa

This work aimed at describing the first biochemical and structural data of a lectin belonging to Swartzieae, a primitive Legume Taxa. A lactose-binding seed lectin (SLL) was purified by affinity chromatography of crude saline extracts of Swartzia laevicarpa on immobilized lactose. The SLL agglutinated rabbit erythrocytes but not rat or human (A, B, O) erythrocytes. Lectin activity was retained after heating at 100 �C for 15 min and was best inhibited by Nacetylgalactosamine, lactose and galactose. The lectin exhibited a single electrophoretic pattern that corresponded to a molecular mass of 29,000 Da, which was confirmed by MS analysis. In addition, the lectin reacted positively with Schiff's reagent. The unique N-terminal amino acid sequence (39 residues) and the internal peptide sequence were determined by Edman degradation and MS/MS, respectively. The sequencing revealed complete homology of the SLL with legume lectins belonging to primitive groups (Dalbergieae and Sophoreae). The SLL (at 1 mg/ml) did not exhibit antifungal activity against various phytopathogens or cytotoxicity (at 100 μg/ml) towards different cancer cell lines.

Leaf water potential, gas exchange and chlorophyll a fluorescence in acariquara seedlings (Minquartia guianensis Aubl.) under water stress and recovery

The physiological performance of acariquara (Minquartia guianensis) seedlings submitted to water deficit and the recovery of physiological parameters during rehydration were investigated in a greenhouse experiment. The analyzed parameters were: leaf water potential, gas exchange and chlorophyll a fluorescence. After thirty-five days, non-irrigated plants exhibited a leaf water potential 70 % lower compared to control plants (irrigated daily) and the stomatal conductance reached values close to zero, inducing a severe decrease in gas exchange (photosynthesis and transpiration). Six days after the beginning of the rehydration of drought-stressed plants, the results demonstrated that water stress did not irreversibly affect gas exchange and quantum efficiency of photosystem II (PSII) in M. guianensis seedlings, since four to six days after rehydration the plants exhibited total recovery of the photosynthetic apparatus. We conclude that M. guianensis presented good tolerance to water stress and good capacity to recover the physiological performance related to leaf water status, photosynthesis and photochemical efficiency of PS II under hydric stress, suggesting substantial physiological plasticity during the juvenile phase for this tree species.

Growth, photosynthesis and stress indicators in young rosewood plants (Aniba rosaeodora Ducke) under different light intensities

Aniba rosaeodora is an Amazonian tree species that belongs to the family Lauraceae. Due to intense exploitation for extraction of essential oils (mainly linalol), A. rosaeodora is now considered an endangered species. On the other hand, there is little information about its ecophysiology which would be useful to support future forest planting programs. Hence, the effect of different light intensities on the growth and photosynthetic characteristics of young plants of A. rosaeodora was studied. Nine-month-old plants were subjected to four light treatments (T1= 10 a 250 µmol.m-2.s-1 / control; T2=500 to 800, T3=700 to 1000 and T4=1300 to 1800 µmol.m-2.s-1 / full sunlight). Allometric variables, gas exchange, contents of pigments and chlorophyll a fluorescence were analysed. As to the relative growth rates, it was found that plants of A. rosaeodora showed higher biomass accumulation when grown under intermediary irradiance conditions (T2). The best photosynthetic performance was achieved under conditions of T3. When growth was correlated with photosynthesis, it was found that plants under treatments T2 and T3 presented better responses in comparison with the lowest (T1) and highest (T4) light extremes. The highest pigment contents were obtained for plants in the shade (T1) and the lowest for those exposed to full sunlight (T4). The photochemical efficiency of photosystem II (Fv/Fm) was found that only plants in the shade treatment (T1) presented no stress from high irradiance. These findings suggest that both treatments (T1 and T4) altered the function of the A. rosaeodora plants, inhibiting photosynthesis and growth. Plants of A. rosaeodora developed photo-protection mechanisms under full sunlight. However, the species presented better photosynthetic response and biomass gain under intermediary irradiance conditions, displaying relative physiological plasticity, during the seedling phase.

Unicystic ameloblastoma: a possible pitfall in periapical diagnosis

AIM

To report a clinical case of unicystic ameloblastoma previously misdiagnosed as radicular cyst.

SUMMARY

A 49-year-old white male was referred to a private practitioner complaining of an asymptomatic bony hard swelling of the left posterior mandible. The patient's dental history indicated that his left mandibular first molar had been extracted approximately 10 years previously. At that time, preoperative radiographic examination demonstrated a radiolucent area of 1.5 cm diameter with well-defined margins involving the distal root of tooth 36. The lesion was diagnosed as cystic and surgery for its removal was advised, but not performed. At presentation, radiography demonstrated a well-defined 3 cm diameter radiolucency extending from the second premolar to the second molar. The lesion was enucleated and histopathological examination confirmed a diagnosis of unicystic ameloblastoma.

KEY LEARNING POINTS

*Despite a clinical diagnosis of periapical disease of endodontic origin, a nonendodontic lesion may be present. *Unicystic ameloblastoma located on the periapical area of a tooth can lead to a pulp-periapical misdiagnosis, and should be considered in differential diagnosis. *All tissue specimens recovered in apical surgery should be submitted to histopathological analysis.