Analysis of the Diversity of Substrate Utilisation of Soil Bacteria Exposed to Cd and Earthworm Activity Using Generalised Additive Models

Biolog EcoPlates™ can be used to measure the carbon substrate utilisation patterns of microbial communities. This method results in a community-level physiological profile (CLPP), which yields a very large amount of data that may be difficult to interpret. In this work, we explore a combination of statistical techniques (particularly the use of generalised additive models [GAMs]) to improve the exploitation of CLPP data. The strength of GAMs lies in their ability to address highly non-linear relationships between the response and the set of explanatory variables. We studied the impact of earthworms (Aporrectodea caliginosa Savigny 1826) and cadmium (Cd) on the CLPP of soil bacteria. The results indicated that both Cd and earthworms modified the CLPP. GAMs were used to assess time-course changes in the diversity of substrate utilisation (DSU) using the Shannon-Wiener index. GAMs revealed significant differences for all treatments (compared to control -S-). The Cd exposed microbial community presented very high metabolic capacities on a few substrata, resulting in an initial acute decrease of DSU (i.e. intense utilization of a few carbon substrata). After 54 h, and over the next 43 h the increase of the DSU suggest that other taxa, less dominant, reached high numbers in the wells containing sources that are less suitable for the Cd-tolerant taxa. Earthworms were a much more determining factor in explaining time course changes in DSU than Cd. Accordingly, Ew and EwCd soils presented similar trends, regardless the presence of Cd. Moreover, both treatments presented similar number of bacteria and higher than Cd-treated soils. This experimental approach, based on the use of DSU and GAMs allowed for a global and statistically relevant interpretation of the changes in carbon source utilisation, highlighting the key role of earthworms on the protection of microbial communities against the Cd.     

2,4,5-trimethoxycinnamic acid: the major metabolite of α-asarone,retains most of the pharmacological properties of α-asarone

2,4,5-trimethoxycinnamic acid (TMC), the major and non toxic metabolite of α-asarone (2,4,5-trimethoxy-1-propenyl benzene), retains most of the pharmacological properties of α-asarone, since both substances, administered to hypercholesterolemic rats at 80 mg/kg body wt, decreased total serum cholesterol, lowered LDL-cholesterol levels and kept unaffected HDL-cholesterol levels. In addition, both substances increased bile flow, especially in hypercholesterolemic rats, by rising the secretion of bile salts, phospholipids and bile cholesterol. These drugs also reduced cholesterol levels of gallbladder bile, whereas phospholipids and bile salts concentrations were increased, decreasing the cholesterol saturation index (CSI). We also found that α-asarone was 20 times better inhibitor of HMG-CoA reductase than TMC. This effect on HMG-CoA reductase was the only property highly reduced in TMC in comparison with α-asarone, while the other pharmacological properties of α-asarone were retained by TMC. These experiments strongly suggest that TMC can be further studied as a possible hypocholesterolemic and cholelitholytic agent.     

Plant heat shock protein 70 as carrier for immunization against a plant-expressed reporter antigen

Mammalian Heat Shock Proteins (HSP), have potent immune-stimulatory properties due to the natural capability to associate with polypeptides and bind receptors on antigen presenting cells. The present study was aimed to explore whether plant HSP, and in particular HSP70, share similar properties. We wanted in particular to evaluate if HSP70 extracted in association to naturally bound polypeptides from plant tissues expressing a recombinant “reporter” antigen, carry antigen-derived polypeptides and can be used to activate antigen-specific immune responses. This application of HSP70 has been very poorly investigated so far. The analysis started by structurally modeling the plant protein and defining the conditions that ensure maximal expression levels and optimal recovery from plant tissues. Afterwards, HSP70 was purified from Nicotiana benthamiana leaves transiently expressing a heterologous “reporter” protein. The purification was carried out taking care to avoid the release from HSP70 of the polypeptides chaperoned within plant cells. The evaluation of antibody titers in mice sera subsequent to the subcutaneous delivery of the purified HSP70 demonstrated that it is highly effective in priming humoral immune responses specific to the plant expressed “reporter” protein. Overall results indicated that plant-derived HSP70 shares structural and functional properties with the mammalian homologue. This study paves the way to further investigations targeted at determining the properties of HSP70 extracted from plants expressing foreign recombinant antigens as a readily available immunological carrier for the efficient delivery of polypeptides derived from these antigens.     

Effects of sensorial denervation induced by capsaicin injection at birth or on day three of life,on puberty,induced ovulation and pregnancy

Evidence that ovarian innervation plays a role in the regulation of ovarian functions has been widely reported. The present study analyzed the effects of treating neonatal rats with capsaicin on: the onset of puberty, serum hormone levels, timing of first vaginal estrus, ovulation rates, ovarian and uterine weights, follicular development, and noradrenaline concentration in the ovaries. The study was based on two experimental models: untouched rats and hemispayed animals. The results indicate that newborns treated with capsaicin did not show changes in the onset of puberty, though the number of ova shed by these animals was lower than in control rats. The number of follicles counted in the ovaries of newborn, or 3-day old-capsaicin-treated animals, was significantly lower and showed an increase in the number of atretic follicles compared to vehicle treated rats. All capsaicin treated animals copulated, but only 6/23 delivered pups. The number of ova shed by capsaicin-treated animals after eCG or eCG-hCG treatment was significantly lower than in the control group. Present results could indicate that some specific neural information registered in the ovary is sent to the central nervous system, and that such information plays a role in the mechanism regulating ovarian function.     

Vocal Repertoire of Captive Capybara (Hydrochoerus hydrochaeris): Structure,Context and Function

In this work we describe the structure, behavioral context and functionality of the vocal repertoire of capybaras, a social Caviomorph rodent. Additionally, since territoriality is present in this species, we hypothesize the occurrence of vocal differences among social groups. We analyzed a total of 2069 calls emitted by 28 animals from three different social groups. The capybara’s repertoire is comprised by seven call types (whistle, cry, whine, squeal, bark, click and tooth‐chattering). The vocalizations were functionally categorized as contact, alarm, distress and agonistic calls considering their behavioral contexts. The click calls emitted by the adults of the three captive capybara groups were significantly different, confirming our hypothesis of social groups’ vocal differences. The richness of interactions mediated by vocalization in capybaras suggests that the species’ communication is an important mechanism to regulate social encounters and to alert members of the group about environmental cues.     

Apical meristem exhaustion during determinate primary root growth in the moots koom 1 mutant of Arabidopsis thaliana

An indeterminate developmental program allows plant organs to grow continuously by maintaining functional meristems over time. The molecular mechanisms involved in the maintenance of the root apical meristem are not completely understood. We have identified a new Arabidopsis thaliana mutant named moots koom 1 (mko1) that showed complete root apical meristem exhaustion of the primary root by 9?days post-germination. MKO1 is essential for maintenance of root cell proliferation. In the mutant, cell division is uncoupled from cell growth in the region corresponding to the root apical meristem. We established the sequence of cellular events that lead to meristem exhaustion in this mutant. Interestingly, the SCR and WOX5 promoters were active in the mko1 quiescent center at all developmental stages. However, during meristem exhaustion, the mutant root tip showed defects in starch accumulation in the columella and changes in auxin response pattern. Therefore, contrary to many described mutants, the determinate growth in mko1 seedlings does not appear to be a consequence of incorrect establishment or affected maintenance of the quiescent center but rather of cell proliferation defects both in stem cell niche and in the rest of the apical meristem. Our results support a model whereby the MKO1 gene plays an important role in the maintenance of the root apical meristem proliferative capacity and indeterminate root growth, which apparently acts independently of the SCR/SHR and WOX5 regulatory pathways.     

Wildlife farming: an alternative to unsustainable hunting and deforestation in Neotropical forests?

Wild animals have been a source of food and income through subsistence hunting by forest-dwelling people in Neotropical countries in spite of the fact that hunting appears to be unsustainable as it leads to the depletion of wild fauna. Laws in Brazil and other Latin American countries forbid hunting but allow the commercial use of captive-bred animals. Notwithstanding the fact that this is a controversial topic among conservationists, in this paper we propose that wildlife farming in the Neotropics can be an alternative to the over-hunting and deforestation that are carried out for the production of traditional food and pastures for livestock. This review sets out this proposal, and discusses the implications for tropical forest integrity and rural population dependency on forest resources. We discuss the ecological and economical advantages of wildlife farming and its constraints as a conservation tool, using collared peccary (Pecari tajacu) farming in the Amazon region as a model. Productivity levels may reach 19,000 times higher than those obtained from the management of peccaries from forests in the Amazon region. This can be achieved with an easily obtainable diet composed of forest fruits and locally available agricultural by-products. Therefore, establishing captive management programs for peccaries is an effective way of avoiding wild stock depletion, deforestation, and guaranteeing the livelihood of forest dwellers in the Neotropics. However, it is essential that governmental and/or non-governmental agencies be involved in providing subsides to establish peccary farms, provide technical assistance, and introducing peccary captive breeding centers to supply founder stock.