Chemical constituents in Baccharis dracunculifolia as the main botanical origin of southeastern Brazilian propolis

Previously, it was reported that one group of propolis (Group 12) was identified in southeastern Brazil, and the botanical origin of the propolis was Baccharis dracunculifolia resinous exudates. It was also observed that honeybee (Africanized Apis mellifera) mainly visited the leaf buds or unexpanded leaves of B. dracunculifolia but rarely expanded leaves. B. dracunculifolia is dioecious with male and female inflorescences, and RPHPLC of the ethanolic extracts of the respective male and female bud resinous exudates showed the same profiles. RPHPLC profiles of propolis G12 leaf buds and unexpanded and expanded leaves of B. dracunculifolia showed similarity, but unexpanded leaves quantitatively decreased in chemical constituents as compared with leaf buds. In the case of expanded leaves, all chemical constituents were severely decreased or disappeared. Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) was also identified in both propolis and resinous exudates, and both ethanolic extracts contained the highest concentrations of this compound as compared with the rest of the chemical constituents.     

Inhibitory effect of yuzu essential oil on the formation of N-nitrosodimethylamine in vegetables

The inhibitory effect of yuzu (Citrus junos Tanaka) essential oil on the formation of N-nitrosodimethylamine (NDMA) in the presence of vegetables (31 species) or saliva was investigated by HPLC. Most vegetable extracts enhanced the formation of NDMA. However, the formation ratio of NDMA in vegetable extracts was decreased by yuzu oil in the range of 59 to 22%. In the presence of yuzu oil and saliva, its ratio ranged between 62 and 24%. These results indicated that yuzu oil inhibited the formation of NDMA even in vegetables and saliva. The contents of ascorbic acid, nitrate, and nitrite in the 31 vegetable species were 0.3-65 mg/100 g, 3-581 mg/100 g, and 10-750 microg/100 g, respectively. Ascorbic acid and nitrite had little effect on the inhibition or formation of NDMA at their intact levels. Nitrate accelerated the formation of NDMA, and the addition of saliva further enhanced it. The mechanism of inhibition of NDMA formation by alpha-terpinene was studied. It was assumed from the results of LC-MS that a new compound formed by the reaction of alpha-terpinene with nitrite would be a derivative of alpha-terpinene with dinitroso groups. The molecular weight of this compound was 194. It is suggested that terpene hydrocarbons in citrus essential oils would contribute to the decrease of NDMA formation.     

Comparison of the amino acid sequences of acorn barnacle lectins showing different inhibitory activities toward the crystal growth of calcium carbonate

ABSTRACT: The amino acid sequence of a D -galactose-binding lectin isolated from the hemolymph of the acorn barnacle Balanus rostratus was determined. The lectin (BRL) ( M _r 120K) is a multimeric protein whose subunit consists of 182 amino acids. The amino acid sequence was compared with those of multiple lectins (BRA-2, BRA-3) from Megabalanus rosa to explore the relationship between the structures and the inhibitory activity toward the crystal growth of calcium carbonate. Although BRL was 46% identical to BRA-2 and 15% identical to BRA-3, the lectin had no inhibitory activity, unlike BRA-2 and BRA-3. Both the number and the localization of acidic amino acid residues and their amide forms were different among them. Observations by scanning electron microscopy revealed modifications in the size and morphology of the calcium carbonate crystals grown in the presence of the lectins.     

Molecular identification of Candida parapsilosis from crop mucosa in a cockatiel.

A 2-month-old cockatiel was evaluated for diarrhea, dyspnea, and death. Histologic examination of lesions in the crop mucosa revealed hyperkeratosis and the presence of blastoconidia and hyphae. Positive immunohistochemical staining of the organisms was achieved with an antibody directed against Candida spp. Polymerase chain reaction amplification of DNA from crop lesion material with internal transcribed spacer 2 (ITS2) primers yielded fragments of approximately 300 bp, which demonstrated 95% DNA homology with the corresponding sequence from a strain of Candida parapsilosis deposited in the GenBank data base. The Candida species in the lesion of the crop mucosa was therefore identified by DNA sequence analysis as C. parapsilosis.     

Juvenile hormone regulates butterfly larval pattern switches

Insect color patterns can be very diverse. This variation is also seen among many larval instar stages, which can take on vastly different phenotypes. Young caterpillars of the swallowtail butterfly, Papilio xuthus, are mimics of bird droppings, whereas the fifth larval instar is camouflaged among the leaves of host plants (cryptic pattern). We find that juvenile hormone (JH) titers decrease during the fourth larval instar. Furthermore, treatment with JH analog at the beginning of the fourth instar stage resulted in reproducing the mimetic pattern instead of the usual cryptic one and likewise altered gene expression patterns to that associated with the mimetic pattern. These findings suggest that JH regulates the progressive larval pattern switch of this insect.     

Structural requirements of strigolactones for germination induction of Striga gesnerioides seeds

Strigolactones are highly potent germination stimulants for seeds of the parasitic weeds Striga and Orobanche spp. 4-Hydroxy-GR24 and 4-acetoxy-GR24 were prepared and their abilities to induce seed germination of Striga gesnerioides evaluated. Optically active (8bR,2'R)-isomers induced germination, although the racemic diastereomers were inactive. In contrast, the stereoisomer of GR24 with the same configuration induced negligible germination. Some stereoisomers of GR24 and its analogues acted as effective antagonists for induction of seed germination by cowpea root exudates. These results suggest that both an oxygenated substituent at C-4 and the configuration of the tricyclic lactone and the D-ring are essential structural requirements for induction of germination in S. gesnerioides seeds.     

Changes in esculeoside A content in different regions of the tomato fruit during maturation and heat processing

We previously demonstrated that esculeogenin A, a new aglycone of the tomato sapogenol esculeoside A, inhibits both acyl coenzyme A:cholesterol acyl-transferase (ACAT)-1 and -2 and ameliorates the pathogenesis of atherosclerosis in apoE deficient mice. Although we believe that daily intake of esculeoside A from tomato products can play a beneficial role in preventing the pathogenesis of atherosclerosis, the compound is not being used for preventive medicine due to the lack of information on methods for quantitative analysis and the content and stability of the compound in tomato products. In the present study, we report the development of a high-performance liquid chromatography (HPLC) method using an instrument equipped with a refractive index (RI) detector for esculeoside A quantification. We used this method to measure the changes in esculeoside A content during maturation, its distribution in the fruit body, and its stability during the heating process. The contents of esculeoside A in cherry tomatoes and Momotaro tomatoes were 21- and 9-fold, respectively, higher than that of lycopene, which is the most well-known compound in tomatoes. Furthermore, the esculeoside A content in pericarp wall was higher than in the whole tomato fruit and increased in a time-dependent manner during maturation. Although the melting point of purified esculeoside A was 225 °C, the esculeoside A in crude tomato extract decreased in a temperature-dependent manner. Degradation due to the heating process was inhibited under a pH of 9. These results demonstrated that the esculeoside A content differs in the various types of tomatoes, during maturation, and during the heating process used for preservation.     

Retroviral DNA integration directed by HIV integration protein in vitro

Efficient retroviral growth requires integration of a DNA copy of the viral RNA genome into a chromosome of the host. As a first step in analyzing the mechanism of integration of human immunodeficiency virus (HIV) DNA, a cell-free system was established that models the integration reaction. The in vitro system depends on the HIV integration (IN) protein, which was partially purified from insect cells engineered to express IN protein in large quantities. Integration was detected in a biological assay that scores the insertion of a linear DNA containing HIV terminal sequences into a lambda DNA target. Some integration products generated in this assay contained five-base pair duplications of the target DNA at the recombination junctions, a characteristic of HIV integration in vivo; the remaining products contained aberrant junctional sequences that may have been produced in a variation of the normal reaction. These results indicate that HIV IN protein is the only viral protein required to insert model HIV DNA sequences into a target DNA in vitro.