Analysis from avian visual perspective reveals plumage colour differences among females of capuchino seedeaters (Sporophila)

Females of the closely related capuchino seedeaters are difficult to distinguish from one another based on human visual perception of colouration and morphology. We examined plumage colour differences among females of four species, the tawny‐bellied seedeater Sporophila hypoxantha, the dark‐throated seedeater S. ruficollis, the rufous‐rumped seedeater S. hypochroma, and the chesnut‐bellied seedeater S. cinnamomea. Reflectance values were measured on museum skins, and interspecific differences were analyzed using the Vorobyev‐Osorio avian colour discrimination model. Interspecific distances in the colour space calculated by the model were considerably higher than the threshold for colour discrimination, indicating the presence of colour differences among species that should be detectable by birds. Colour differences between S. hypoxantha and the other three species were the largest. A Discriminant Function Analysis showed that UV‐wavelength was particularly important in species separation. Our results indicate that female plumage of these four species is considerably divergent in colour; these differences being imperceptible to the human eye, thus representing previously unknown morphological evolution in these species.     

Production of L-Phenylacetyl Carbinol by Immobilized Cells of Saccharomyces Cerevisiae

Conversion of benzaldehyde to L-phenylacetyl carbinol (L-PAC) was achieved with immobilized, growing cells of Saccharomyces cerevisiae in different reactors. Product formation increased (31%) with the subsequent initial reuses of the entrapped cells. Biomass production and PAC formation depleted (40 and 57%, respectively) after 4-5 continuous growth and biotransformation cycles. With the regeneration of the biocatalysts, catalytic activity of the cells was resumed. The highest yields were in a stirred tank reactor (29 g PAC) from 77 g benzeldehyde with 14 repeated uses of entrapped cells.     

NMR of alpha-synuclein-polyamine complexes elucidates the mechanism and kinetics of induced aggregation

The aggregation of alpha-synuclein is characteristic of Parkinson's disease (PD) and other neurodegenerative synucleinopathies. The 140-aa protein is natively unstructured; thus, ligands binding to the monomeric form are of therapeutic interest. Biogenic polyamines promote the aggregation of alpha-synuclein and may constitute endogenous agents modulating the pathogenesis of PD. We characterized the complexes of natural and synthetic polyamines with alpha-synuclein by NMR and assigned the binding site to C-terminal residues 109-140. Dissociation constants were derived from chemical shift perturbations. Greater polyamine charge (+2 --> +5) correlated with increased affinity and enhancement of fibrillation, for which we propose a simple kinetic mechanism involving a dimeric nucleation center. According to the analysis, polyamines increase the extent of nucleation by approximately 10(4) and the rate of monomer addition approximately 40-fold. Significant secondary structure is not induced in monomeric alpha-synuclein by polyamines at 15 degrees C. Instead, NMR reveals changes in a region (aa 22-93) far removed from the polyamine binding site and presumed to adopt the beta-sheet conformation characteristic of fibrillar alpha-synuclein. We conclude that the C-terminal domain acts as a regulator of alpha-synuclein aggregation.     

Two new bacterial DNA primase inhibitors from the plant Polygonum cuspidatum

The 70% aqueous methanolic extract of the Peruvian plant Polygonum cuspidatum sp. was found to contain two novel phenolic saccharides 1 and 2, which were identified as inhibitors of the bacterial DNA primase enzyme. Structures of these two compounds were established based on high resolution NMR studies. Compound 1 and 2 inhibited the primase enzyme with an IC(50) of 4 and 5 microM, respectively.     

Three new compounds from the plant Lippia alva as inhibitors of chemokine receptor 5 (CCR5)

The 70% aqueous methanol extract of the Peruvian plant Lippia alva (Verbenaceae) was found to contain three novel compounds, 1, 2, and 3, which were identified as inhibitors of the chemokine receptor CCR5. The structures of 1-3 were established based on extensive NMR studies. Compounds 1-3 inhibited CCR5 receptor signaling as measured by a calcium mobilization assay with IC(50) values of 5.5, 6.0, and 7.2 microg/mL, respectively.     

Early changes in Huntington’s disease patient brains involve alterations in cytoskeletal and synaptic elements

Huntington’s disease (HD) is caused by a polyglutamine repeat expansion in the N-terminus of the huntingtin protein. Huntingtin is normally present in the cytoplasm where it may interact with structural and synaptic elements. The mechanism of HD pathogenesis remains unknown but studies indicate a toxic gain-of-function possibly through aberrant protein interactions. To investigate whether early degenerative changes in HD involve alterations of cytoskeletal and vesicular components, we examined early cellular changes in the frontal cortex of HD presymptomatic (PS), early pathological grade (grade 1) and late-stage (grade 3 and 4) patients as compared to age-matched controls. Morphologic analysis using silver impregnation revealed a progressive decrease in neuronal fiber density and organization in pyramidal cell layers beginning in presymptomatic HD cases. Immunocytochemical analyses for the cytoskeletal markers α -tubulin, microtubule-associated protein 2, and phosphorylated neurofilament demonstrated a concomitant loss of staining in early grade cases. Immunoblotting for synaptic proteins revealed a reduction in complexin 2, which was marked in some grade 1 HD cases and significantly reduced in all late stage cases. Interestingly, we demonstrate that two synaptic proteins, dynamin and PACSIN 1, which were unchanged by immunoblotting, showed a striking loss by immunocytochemistry beginning in early stage HD tissue suggesting abnormal distribution of these proteins. We propose that mutant huntingtin affects proteins involved in synaptic function and cytoskeletal integrity before symptoms develop which may influence early disease onset and/or progression.     

Optimization of an immunostaining protocol for the rapid intraoperative evaluation of melanoma sentinel lymph node imprint smears with the 'MCW melanoma cocktail'

BACKGROUND: In the management of cutaneous melanoma, it is desirable to complete the regional lymphadenectomy during the initial surgical procedure for wide excision of biopsy site and sentinel lymph node (SLN) biopsy. In this study, we optimized and evaluated a rapid 17 minutes immunostaining protocol. The discriminatory immunostaining pattern associated with the 'MCW Melanoma Cocktail' (mixture of Melan- A, MART- 1, and tyrosinase) facilitated the feasibility of intraoperative evaluation of imprint smears of SLNs for melanoma metastases. METHODS: Imprint smears of 51 lymph nodes from 25 cases (48 SLNs and 3 non-SLNs, 1 to 4 SLNs/case) of cutaneous melanoma were evaluated. RESULTS: Sixteen percent, 8/51 lymph nodes (28%, 7/25 cases) were positive for melanoma metastases in immunostained permanent sections with the 'MCW melanoma cocktail'. All of these melanoma metastases, except 1 SLN from 1 case, were also detected in rapidly immunostained wet-fixed and air-dried smears (rehydrated in saline and postfixed in alcoholic formalin). The cytomorphology was superior in air-dried smears, which were rehydrated in saline and postfixed in alcoholic formalin. Wet-fixed smears frequently showed air-drying artifacts, which lead to the focal loss of immunostaining. None of the 5 SLNs from 5 cases exhibiting capsular nevi showed a false positive result with immunostained imprint smears. CONCLUSIONS: Melanoma metastases can be detected intraoperatively in both air-dried smears and wet-fixed smears immunostained with the MCW Melanoma cocktail. Air-dried smears rehydrated in saline and postfixed in alcoholic formalin provide superior results and many practical benefits.     

Melatonin blocks inhibitory effects of prolactin on photoperiodic induction of gain in body mass,testicular growth and feather regeneration in the migratory male redheaded bunting (<Emphasis Type="Italic">Emberiza bruniceps</Emphasis>)

Little is known about how hormones interact in the photoperiodic induction of seasonal responses in birds. In this study, two experiments determined if the treatment with melatonin altered inhibitory effects of prolactin on photoperiodic induction of seasonal responses in the Palearctic-Indian migratory male redheaded bunting Emberiza bruniceps. Each experiment employed three groups (N = 6–7 each) of photosensitive birds that were held under 8 hours light: 16 hours darkness (8L:16D) since early March. In the experiment 1, beginning in mid June 2001, birds were exposed to natural day lengths (NDL) at 27 degree North (day length = ca.13.8 h, sunrise to sunset) for 23 days. In the experiment 2, beginning in early April 2002, birds were exposed to 14L:10D for 22 days. Beginning on day 4 of NDL or day 1 of 14L:10D, they received 10 (experiment 1) or 13 (experiment 2) daily injections of both melatonin and prolactin (group 1) or prolactin alone (group 2) at a dose of 20 microgram per bird per day in 200 microliter of vehicle. Controls (group 3) received similar volume of vehicle. Thereafter, birds were left uninjected for the next 10 (experiment 1) or 9 days (experiment 2). All injections except those of melatonin were made at the zeitgeber time 10 (ZT 0 = time of sunrise, experiment 1; time of lights on, experiment 2); melatonin was injected at ZT 9.5 and thus 0.5 h before prolactin. Observations were recorded on changes in body mass, testicular growth and feather regeneration.