Diabetic gut microbiota dysbiosis as an inflammaging and immunosenescence condition that fosters progression of retinopathy and nephropathy

The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine?N?oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing (“inflammaging”) as well as in T2DM (“metaflammation”) and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches.     

Floristic relationships of the woody component in rocky outcrops savanna areas in Central Brazil

Rocky outcrops usually have a peculiar vegetation which differs from that of the surrounding vegetation matrix. In Brazil, a savanna type (cerrado rupestre) is particularly characterized by rocky outcrops and is one of eleven vegetation types which occur throughout Cerrado biome. It has been scarcely studied in detail. Therefore, the aim of this study was to investigate the phytogeographical patterns of the woody species in ten areas of the rocky outcrop savanna in the Brazilian Central Plateau. The difference in spatial distribution of the species was assessed through indicator species and CCA ordination analyses. Ten indicator species showed significantly different distribution. The first axis of the ordination showed association with the edaphic gradient, based on maximum temperature, pH and physical properties of the soils (eigenvalue 0.63). The second axis showed an eigenvalue 0.46, associated with poor rainfall and land declivity. It appears that the woody flora of the rocky outcrop savanna areas of the Brazilian Central Plateau is relatively homogeneous, with low β diversity. Apparently, the size of the woody species populations is what distinguishes the ten investigated areas. Therefore, initiatives and actions for the Cerrado biome conservation must consider not only the size of the protected areas but also that of the populations to be protected, especially the woody species on rocky outcrops.     

Possible Host Adaptation as an Evolution Factor of Cowpea aphid‐borne mosaic virus Deduced by Coat Protein Gene Analysis

Cowpea aphid‐borne mosaic virus (CABMV) causes major diseases in cowpea and passion flower plants in Brazil and also in other countries. CABMV has also been isolated from leguminous species including, Cassia hoffmannseggii, Canavalia rosea, Crotalaria juncea and Arachis hypogaea in Brazil. The virus seems to be adapted to two distinct families, the Passifloraceae and Fabaceae. Aiming to identify CABMV and elucidate a possible host adaptation of this virus species, isolates from cowpea, passion flower and C. hoffmannseggii collected in the states of Pernambuco and Rio Grande do Norte were analysed by sequencing the complete coat protein genes. A phylogenetic tree was constructed based on the obtained sequences and those available in public databases. Major Brazilian isolates from passion flower, independently of the geographical distances among them, were grouped in three different clusters. The possible host adaptation was also observed in fabaceous‐infecting CABMV Brazilian isolates. These host adaptations possibly occurred independently within Brazil, so all these clusters belong to a bigger Brazilian cluster. Nevertheless, African passion flower or cowpea‐infecting isolates formed totally different clusters. These results showed that host adaptation could be one factor for CABMV evolution, although geographical isolation is a stronger factor.     

Fate of mimosine administered orally to sheep and its effectiveness as a defleecing agent.

Mimosine was administered orally to Merino sheep once daily for periods of 1-3 days, either as the isolated compound or in the foliage of Leucaena leucocephala. A single daily dose of mimosine of 450 or 600 mg/kg body weight was effective for defleecing sheep. A daily dose rate of 300 mg/kg was effective for defleecing sheep if given on two successive days. The effectiveness of a treatment for defleecing sheep was related to the concentration of mimosine in plasma following dosing; defleecing ensued when the concentration of mimosine in plasma was maintained above 0-1 mmol/l for at least 30 h. The main products excreted in urine were mimosine and 3,4-dihydroxypyridine (DHP); small amounts of mimosinamine were also excreted. During the first day following dosing, the major excretory product was mimosine; DHP was an important component during the second and third days. In the three days following the start of dosing, between 32 and 53% of the mimosine given was accounted for as mimosine in the urine. Following an intravenous infusion of mimosine, no DHP was detected in urine; most of the mimosine was excreted intact but a small amount (c. 9%) was excreted as mimosinamine.     

Prevalence of human immunodeficiency virus infection in alcoholics

To verify the prevalence of infection by human immunodeficiency virus (HIV) in alcoholics we studied 131 alcoholic patients (119 males and 12 females) with a mean age of 44.3 +/- 10.8 years. Serum samples were collected from this group and analysed, by ELISA, for antibodies against HIV as well as for serological markers for hepatitis B virus (HBV) and hepatitis C virus (HCV). As we have previously described, we found a high prevalence of HBV (26.4%) and HCV (4.2%) markers as compared to the prevalence of these markers in samples of normal blood donors from Uberlandia's Hemocentro Regional, which are 4% and 0.4%, respectively. Of the 131 patients, four (3%) had antibodies against HIV, three (75%) of which were injecting drug users (IDU). In the HIV-negative group, only one patient was an IDU. The prevalence of HIV in our population, according to data from the city's Health Secretary, varies from 3.1% to 6.2%. We conclude that, at least for the moment, alcoholism per se, did not constitute an important risk factor for HIV infection. However, acquired immunodeficiency syndrome is a rather recent disease as compared to hepatitis B and C and, as the transmission routes are similar for HIV and hepatitis viruses, an increase in the incidence of HIV infection in alcoholics may be just a question of time.     

Genetic composition,population structure and phylogeography of the loggerhead sea turtle: colonization hypothesis for the Brazilian rookeries

The loggerhead sea turtle, Caretta caretta, is the most common species of sea turtle nesting in Brazil and is listed as endangered by the IUCN. Our study characterizes the genetic structure of loggerheads in Brazil based on mitochondrial DNA control region variability and presents a hypothesis for the colonization of Brazilian rookeries. We analyzed 329 samples from Brazilian rookeries and an oceanic foraging ground, and we compared our results with previously published data for other loggerhead populations. Brazilian rookeries had four haplotypes, none of which have been reported for rookeries outside Brazil. Six haplotypes were found in the foraging aggregation. The presence of the CC-A4 haplotype at all sampled sites and the low nucleotide diversity suggest a common origin for all rookeries, with CC-A4 being the ancestral haplotype of the Brazilian populations. The occurrence of three haplotypes in the foraging aggregation that are known only from rookeries outside of Brazil is consistent with the transoceanic migratory behavior of loggerheads. Our results indicated that the colonization of Brazilian rookeries probably occurred from the southern USA stock. This recent colonization most likely followed a north to south route along the Brazilian coastline, influenced by the Brazilian warm current. Our results further suggest the existence of two genetic population units of loggerheads in Brazil and corroborate natal homing behavior in loggerheads.     

Müller Glia as an Active Compartment Modulating Nervous Activity in the Vertebrate Retina: Neurotransmitters and Trophic Factors

Müller cells represent the main type of glia present in the retina interacting with most, if not all neurons in this tissue. Müller cells have been claimed to function as optic fibers in the retina delivering light to photoreceptors with minimal distortion and low loss [Franze et al (2007) Proc Natl Acad Sci 104:8287–8292]. Most of the mediators found in the brain are also detected in the retinal tissue, and glia cells are active players in the synthesis, release, signaling and uptake of major mediators of synaptic function. Müller glia trophic factors may regulate many different aspects of neuronal circuitry during synaptogenesis, differentiation, neuroprotection and survival of photoreceptors, Retinal Ganglion Cells (RGCs) and other targets in the retina. Here we review the role of several transmitters and trophic factors that participate in the neuron-glia loop in the retina. Special issue article in honor of Dr. Ricardo Tapia.     

Strategies for PHA production by mixed cultures and renewable waste materials

Production of polyhydroxyalkanoates (PHA) by mixed cultures has been widely studied in the last decade. Storage of PHA by mixed microbial cultures occurs under transient conditions of carbon or oxygen availability, known respectively as aerobic dynamic feeding and anaerobic/aerobic process. In these processes, PHA-accumulating organisms, which are quite diverse in terms of phenotype, are selected by the dynamic operating conditions imposed to the reactor. The stability of these processes during long-time operation and the similarity of the polymer physical/chemical properties to the one produced by pure cultures were demonstrated. This process could be implemented at industrial scale, providing that some technological aspects are solved. This review summarizes the relevant research carried out with mixed cultures for PHA production, with main focus on the use of wastes or industrial surplus as feedstocks. Basic concepts, regarding the metabolism and microbiology, and technological approaches, with emphasis on the kind of feedstock and reactor operating conditions for culture selection and PHA accumulation, are described. Challenges for the process optimization are also discussed.