In vitro REGENERATION OF PIGEON PEA USING LEAF EXPLANTS

Pigeon pea ( Cajanus cajan (L.) Millsp.) is a drought tolerant pulse legume, mainly grown for grain in the semi-arid tropics, particularly in Africa. Pigeon pea production in countries like Kenya is faced with a number of challenges, particularly lack of high quality seeds. The objective of this study was to develop an in vitro regeneration system for pigeon pea varieties grown in Kenya, that is amenable to genetic transformation. In vitro regeneration of pigeon pea varieties, KAT 60/8 and ICEAP 00557, commonly grown in Kenya was achieved using leaf explants from in vitro grown seedlings, through callus initiation, followed by shoot and root induction. For callus initiation, MS media supplemented with 0.5-4 mg l-1 2, 4-D and TDZ separately were tested, and IBA at 0.1, 0.5 and 1 mg l-1 was tested for rooting of shoots. Embryogenic calli was obtained on MS containing 2, 4- D; whereas TDZ induced non-embryogenic callus alone or with shoots directly on explants. Indirect shoot regeneration frequency of 6.7 % was achieved using 1 mg l-1 2, 4-D-induced embryogenic callus obtained using KAT 60/8 explants. Whereas direct shoot regeneration frequencies of 20 and 16.7% were achieved using ICEAP 00557 and KAT 60/8 explants, using 0.5 mg l-1 and 2 mg l-1 TDZ, respectively. Optimum rooting was achieved using 0.5 mg l-1 IBA; and up to 92% rooted shoots were successfully established in soil after acclimatisation. Genotype and hormone concentrations had a significant (P<0.05) influence on callus, shoot and root induction. The protocol developed can be optimised for mass production and genetic transformation of KAT 60/8 variety.

Antiplasmodial activity of iron(II) and ruthenium(II) organometallic complexes against Plasmodium falciparum blood parasites

This work reports the in vitro activity against Plasmodium falciparum blood forms (W2 clone, chloroquine-resistant) of tamoxifen-based compounds and their ferrocenyl (ferrocifens) and ruthenocenyl (ruthenocifens) derivatives, as well as their cytotoxicity against HepG2 human hepatoma cells. Surprisingly with these series, results indicate that the biological activity of ruthenocifens is better than that of ferrocifens and other tamoxifen-like compounds. The synthesis of a new metal-based compound is also described. It was shown, for the first time, that ruthenocifens are good antiplasmodial prototypes. Further studies will be conducted aiming at a better understanding of their mechanism of action and at obtaining new compounds with better therapeutic profile.

First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes

This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilmgrowing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management.

Salivary cortisol level and uncooperative behavior in pediatric dental practice

Aim: To investigate the relation between uncooperative behavior and salivary cortisol level in children who underwent preventive dental care. Methods: The sample was composed by 10 children of both sexes aged 40 to 52 months, presenting uncooperative behavior during dental preventive treatments. The saliva collection was performed using a cotton wheel and an Eppendorf tube (Sarstedt Salivete®) in 3 different moments: a) at home, on a day without dental treatment and at the same time on the day of the sessions treatment; b) 30 min after the end of the session, when there was manifestation of uncooperative behavior; c) 30 min after the end of the session, when there was a cooperative behavior of the child. A sample of saliva was centrifuged for 5 minutes at 2400 rpm, 1 of mL of saliva was pipetted in an Eppendorf tube and stored in a freezer at -20 ° C. For the determination of the levels of salivary cortisol was used an Active® kit for cortisol enzyme immunoassay (EIA) DSL-10-67100, composed of specific rabbit antibody anti-cortisol. Data were analyzed statistically for the uncooperative behavior issued in the beginning and at the end of sessions, using the paired t test (p<0.05) and for cortisol levels in saliva samples at home, after the beginning and at the end of sessions, using repeated-measures ANOVA and Tukey’s test (p<0.05). Results: During expression of uncooperative behavior in preventive dental care sessions the salivary cortisol level was significantly higher (0.65 ± 0.25 μg/dL) compared with expression of collaborative behavior (0.24 ± 0.10 μg/dL). Conclusions: It is possible to conclude that, even under preventive intervention, the stress must be controlled in order to reduce dental anxiety and fear.