Synthesis and biological studies of glycosyl dopamine derivatives as potential antiparkinsonian agents

A new approach to deliver dopamine into the central nervous system, based on the use of D-glucose as transportable agent, has been studied. Glycosyl dopamine derivatives bearing the sugar moiety linked to either the amino group or the catechol ring of dopamine through amide, ester or glycosidic bonds were synthesised as potential antiparkinsonian agents. Studies on the binding to dopamine D2 receptor, in vitro stability, and locomotive effect in mice of the synthetic glycoconjugates are reported.     

Icetexane and abietane diterpenoids from Salvia gilliessi

One icetexane and two abietane diterpenes were isolated from the aerial parts of Salvia gilliesii, and characterized as 5-epi-icetexone; 12-hydroxy-11,14-diketo-6,8,12-abietatrien-19,20-olide and 6 alpha,12,19-trihydroxy-11,14-diketo-8,12-abietadien-20,7 beta-olide, respectively. The structures were established by analysis of their 1H and 13C NMR spectra with the aid of 2D experiments. The triterpene oleanolic acid was isolated from the same source.     

Construction of a tightly regulated plasmid vector for Streptococcus pneumoniae: controlled expression of the green fluorescent protein

We have constructed a regulated plasmid vector for Streptococcus pneumoniae, based on the streptococcal broad-host-range replicon pLS1. As a reporter gene, we subcloned the gfp gene from Aequorea victoria, encoding the green fluorescent protein. This gene was placed under the control of the inducible P(M) promoter of the S. pneumoniae malMP operon which, in turn, is regulated by the product of the pneumococcal malR gene. Binding of MalR protein to the P(M) promoter is inactivated by growing the cells in maltose-containing media. Highly regulated gene expression was achieved by cloning in the same plasmid the P(M)-gfp cassette and the malR gene, thus providing the MalR regulator in cis. Pneumococcal cells harboring this vector gave a linear response of GFP synthesis in a maltose-dependent mode without detectable background levels in the absence of the inducer.     

The "five-sites" rule and the evolution of red and green color vision in mammals

Amino acid changes S180A (S-->A at site 180), H197Y, Y277F, T285A, and A308S are known to shift the maximum wavelength of absorption (lambda max) of red and green visual pigments toward blue, essentially in an additive fashion. To test the generality of this "five-sites" rule, we have determined the partial amino acid sequences of red and green pigments from five mammalian orders (Artiodactyla, Carnivora, Lagomorpha, Perissodactyla, and Rodentia). The result suggests that cat (Felis catus), dog (Canis familiaris), and goat (Capra hircus) pigments all with AHYTA at the five critical sites have lambda max values of approximately 530 nm, whereas rat (Rattus norvegicus) pigment with AYYTS has a lambda max value of approximately 510 nm, which is accurately predicted by the five-sites rule. However, the observed lambda max values of the orthologous pigments of European rabbit (Oryctolagus cuniculus), white-tailed deer (Odocoileus virginianus), gray squirrel (Sciurus carolinensis), and guinea pig (Cavia procellus) are consistently more than 10 nm higher than the predicted values, suggesting the existence of additional molecular mechanisms for red and green color vision. The inferred amino acid sequences of ancestral organisms suggest that the extant mammalian red and green pigments appear to have evolved from a single ancestral green-red hybrid pigment by directed amino acid substitutions.      

Analysis of the genome of the gram-negative moderate halophiles Halomonas and Chromohalobacter by using pulsed-field gel electrophoresis

The genomes of 11 moderately halophilic bacteria belonging to the genera Halomonas and Chromohalobacter have been analyzed by restriction endonuclease digestion and pulsed-field gel electrophoresis (PFGE). By using the infrequently cutting restriction endonucleases SpeI and SwaI, highly characteristic fingerprintings were obtained for each of the isolates studied. On the basis of the lengths of the SpeI and SwaI fragments, separated by PFGE, the genome size of the 11 strains studied was estimated. The genome size for 8 Halomonas strains ranged from 1450 to 2830 kb, whereas for the 3 Chromohalobacter strains studied it ranged from 1770 to 2295 kb. Finally, we show that macrorestriction fingerprints could be a useful tool to elucidate the taxonomic position of bacteria belonging to the Halomonas–Deleya complex. Received: October 13, 1997 / Accepted: May 12, 1998     

Disease Risk & Landscape Attributes of Tick-Borne Borrelia Pathogens in the San Francisco Bay Area,California

Habitat heterogeneity influences pathogen ecology by affecting vector abundance and the reservoir host communities. We investigated spatial patterns of disease risk for two human pathogens in the Borrelia genus–B. burgdorferi and B. miyamotoi–that are transmitted by the western black-legged tick, Ixodes pacificus. We collected ticks (349 nymphs, 273 adults) at 20 sites in the San Francisco Bay Area, California, USA. Tick abundance, pathogen prevalence and density of infected nymphs varied widely across sites and habitat type, though nymphal western black-legged ticks were more frequently found, and were more abundant in coast live oak forest and desert/semi-desert scrub (dominated by California sagebrush) habitats. We observed Borrelia infections in ticks at all sites where we able to collect >10 ticks. The recently recognized human pathogen, B. miyamotoi, was observed at a higher prevalence (13/349 nymphs = 3.7%, 95% CI = 2.0–6.3; 5/273 adults = 1.8%, 95% CI = 0.6–4.2) than recent studies from nearby locations (Alameda County, east of the San Francisco Bay), demonstrating that tick-borne disease risk and ecology can vary substantially at small geographic scales, with consequences for public health and disease diagnosis.     

Gluconacetobacter diazotrophicus PAL5 possesses an active quorum sensing regulatory system

The endophytic bacterium Gluconacetobacter diazotrophicus colonizes a broad range of host plants. Its plant growth-promoting capability is related to the capacity to perform biological nitrogen fixation, the biosynthesis of siderophores, antimicrobial substances and the solubilization of mineral nutrients. Colonization of and survival in these endophytic niche requires a complex regulatory network. Among these, quorum sensing systems (QS) are signaling mechanisms involved in the control of several genes related to microbial interactions, host colonization and stress survival. G. diazotrophicus PAL5 possesses a QS composed of a luxR and a luxI homolog, and produces eight molecules from the AHL family as QS signals. In this report data are provided showing that glucose concentration modifies the relative levels of these signal molecules. The activity of G. diazotrophicus PAL5 QS is also altered in presence of other carbon sources and under saline stress conditions. Inactivation of the QS system of G. diazotrophicus PAL5 by means of a quorum quenching strategy allowed the identification of extracellular and intracellular proteins under the control of this regulatory mechanism.     

Viral safety characteristics of Flebogamma® DIF,a new pasteurized,solvent-detergent treated and Planova 20 nm nanofiltered intravenous immunoglobulin

A new human liquid intravenous immunoglobulin product, Flebogamma^® DIF, has been developed. This IgG is purified from human plasma by cold ethanol fractionation, PEG precipitation and ion exchange chromatography. The manufacturing process includes three different specific pathogen clearance (inactivation/removal) steps: pasteurization, solvent/detergent treatment and Planova? nanofiltration with a pore size of 20 nm. This study evaluates the pathogen clearance capacity of seven steps in the production process for a wide range of viruses through spiking experiments: the three specific steps mentioned above and also four more production steps. Infectivity of samples was measured using a Tissue Culture Infectious Dose assay (log₁₀ TCID₅₀) or Plaque Forming Units assay (log₁₀ PFU). Validation studies demonstrated that each specific step cleared more than 4 log₁₀ for all viruses assayed. An overall viral clearance between ≥13.33 log₁₀ and ≥25.21 log₁₀, was achieved depending on the virus and the number of steps studied for each virus. It can be concluded that Flebogamma^® DIF has a very high viral safety profile.     

Analysis of apoptosis and Bcl-2 expression in polar forms of leprosy

Apoptosis eliminates pathogen-infected cells. Its modulation can influence the course of infections, permitting the survival of intracellular pathogens. In leprosy, which presents several clinical manifestations related to bacillary burden and host immune status, the mechanisms responsible for the persistence of the bacillus are unknown. Few studies have focused on apoptosis over the disease spectrum and as a defense mechanism against Mycobacterium leprae. We evaluated apoptosis using terminal transferase dUTP nick end labeling and the expression of Bcl-2 by immunohistochemistry in skin lesions from 11 tuberculoid and 15 lepromatous leprosy patients. Each specimen was evaluated by determining the number of positive cells in 10 fields at × 400 magnification. We observed a higher number of apoptotic cells in tuberculoid lesions in comparison with lepromatous leprosy (42.5 cells per 10 fields vs. 11.5 cells per 10 fields, P<0.0001). Expression of Bcl-2, conversely, was larger in lepromatous than in tuberculoid samples (172.0 cells per 10 fields vs. 17.7 cells per 10 fields, P<0.0001). These observations suggest modulation of apoptosis in leprosy, primarily in lepromatous patients, for which the decrease in cell death could support M. leprae survival and contribute to the success of infection. Conversely, in tuberculoid patients, apoptosis could contribute to reducing propagation of the bacillus.