Neotropical bromeliads as food sources for birds: a systematic review and perspectives on the management of ecological interactions

The loss of interactions and ecosystem functions is a concerning by-product of pervasive Anthropocene species decline and extinction. Ecological interactions between species sustain the provision of ecosystem processes, especially those mediated by trophic relationships such as pollination and predation. At the local habitat scale, the diversity of natural food sources may increase the diversity of interactions, thus enhancing the stability of local communities and ecosystem functioning. Here I discuss the importance of bromeliads as a potential provider of additional trophic interactions with birds, a key animal group in the Neotropics. Based on 88 studies published between 1965 and 2020 across the Neotropical region, I observed that bromeliads act as ‘wildlife restaurants’ by providing an additional food source throughout the year in almost all Neotropical ecosystems for at least 162 bird species (mostly hummingbirds). These plants (both epiphytic and terrestrial forms) can provide nectar, flowers, water for drinking, invertebrates, small vertebrates, seeds, and fruits, as well as nest materials and substrates. Given these trophic relationships between bromeliads and birds, actions to restore the richness and abundance of these plants in changed habitats would potentially enhance the local diversity of birds. I discuss and recommend the use of bromeliad transplantations as a relevant conservation tool for birds and some implications for the maintenance of species and interaction diversity in natural and agricultural habitats.     

Endostatin gene therapy enhances the efficacy of IL-2 in suppressing metastatic renal cell carcinoma in mice

We investigated whether the administration of IL-2 combined with endostatin gene therapy was able to produce additive or even synergistic immunomodulatory activity in a mouse model of metastatic renal carcinoma. Renca cells were injected into the tail vein of BALB/c mice. After 24 h, the animals were randomly divided into four groups (5 mice/group). One group of mice was the control, the second group received treatment with 100,000 UI of Recombinant IL-2 (Proleukin, Chiron) twice a day, 1 day per week during 2 weeks (IL-2), the third group received treatment with a subcutaneous inoculation of 3.6 × 10⁶ endostatin-producing cells, and the fourth group received both therapies (IL-2 + ES). Mice were treated for 2 weeks. In the survival studies, 10 mice/group daily, mice were monitored daily until they died. The presence of metastases led to a twofold increase in endostatin levels. Subcutaneous inoculation of NIH/3T3-LendSN cells resulted in a 2.75 and 2.78-fold increase in endostatin levels in the ES and IL-2 + ES group, respectively. At the end of the study, there was a significant decrease in lung wet weight, lung nodules area, and microvascular area (MVA) in all treated groups compared with the control group (P < 0.001). The significant difference in lung wet weight and lung nodules area between groups IL-2 and IL-2 + ES revealed a synergistic antitumor effect of the combined treatment (P < 0.05). The IL-2 + ES therapy Kaplan–Meier survival curves showed that the probability of survival was significantly higher for mice treated with the combined therapy (log-rank test, P = 0.0028). Conjugated therapy caused an increase in the infiltration of CD4, CD8 and CD49b lymphocytes. An increase in the amount of CD8 cells (P < 0.01) was observed when animals received both ES and IL-2, suggesting an additive effect of ES over IL-2 treatment. A synergistic effect of ES on the infiltration of CD4 (P < 0.001) and CD49b cells (P < 0.01) was also observed over the effect of IL-2. Here, we show that ES led to an increase in CD4 T helper cells as well as cytotoxic lymphocytes, such as NK cells and CD8 cells, within tumors of IL-2 treated mice. This means that ES plays a role in supporting the actions of T cells.     

Seasonal flooding regime and ecological traits influence genetic structure of two small rodents

Although codistributed species are affected by the same abiotic factors, such as rivers and seasonal flooding regimes, ecological traits, such as locomotion habits and habitat preferences, may also influence differences in levels of genetic diversity and differentiation. We examined population genetic structure and diversity of Hylaeamys megacephalus and Oecomys aff. roberti, two cricetid rodent species from the mid‐Araguaia River in central Brazil, using mitochondrial DNA sequence data. Specifically, we aim to test whether the Araguaia River acts as a barrier to the gene flow of these two species and to assess how ecological traits, such as locomotion habits and habitat preferences, may influence differences in levels of genetic diversity and differentiation. As both species occur in flooded forests, neither showed genetic differences related to river banks. Oecomys aff. roberti showed stronger population structure that appears to be associated with isolation by distance. This arboreal species maintained stable populations in the Araguaia River, while the terrestrial H. megacephalus was more affected by seasonal floods, resulting in a genetic signature of population expansion. Our initial predictions were largely supported by our results given that locomotion habits and habitat preferences of each species appears to have played a role on the genetic structure of these two sympatric rodent species.     

Hyperossification in miniaturized toadlets of the genus Brachycephalus (Amphibia: Anura: Brachycephalidae): Microscopic structure and macroscopic patterns of variation

Species of the genus Brachycephalus, have a snout‐vent length of less than 18 mm and are believed to have evolved through miniaturization. Brachycephalus ephippium, is particularly interesting; because its entire skull is hyperossified, and the presacral vertebrae and transverse processes are covered by a dorsal shield. We demonstrate in this paper that, at the macroscopic level, a completely hyperossified skull and dorsal shield occur only in B. ephippium, but not in B. ferruginus, B. izechsohni, B. pernix, B. pombali, B. brunneus, B. didactylus, and B. hermogenesi. An intermediate condition, in which the skull is hyperossified but a dorsal shield is absent, occurs in B. vertebralis, B. nodoterga, B. pitanga, and B. alipioi. The microscopic structure of hyperossification was examined in skulls of B. ephippium and B. pitanga, revealing a complex organization involving the presence of Sharpey fibers, which in humans are characteristic of periodontal connections. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

Antimicrobial and antiadhesive properties of a biosurfactant isolated from Lactobacillus paracasei ssp. paracasei A20

Aims: The aim of this study was to determine the antimicrobial and antiadhesive properties of a biosurfactant isolated from Lactobacillus paracasei ssp. paracasei A20 against several micro‐organisms, including Gram‐positive and Gram‐negative bacteria, yeasts and filamentous fungi. Methods and Results: Antimicrobial and antiadhesive activities were determined using the microdilution method in 96‐well culture plates. The biosurfactant showed antimicrobial activity against all the micro‐organisms assayed, and for twelve of the eighteen micro‐organisms (including the pathogenic Candida albicans, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae), the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were achieved for biosurfactant concentrations between 25 and 50 mg ml^?1. Furthermore, the biosurfactant showed antiadhesive activity against most of the micro‐organisms evaluated. Conclusions: As far as we know, this is the first compilation of data on antimicrobial and antiadhesive activities of biosurfactants obtained from lactobacilli against such a broad group of micro‐organisms. Although the antiadhesive activity of biosurfactants isolated from lactic acid bacteria has been widely reported, their antimicrobial activity is quite unusual and has been described only in a few strains. Significance and Impact of the Study: The results obtained in this study regarding the antimicrobial and antiadhesive properties of this biosurfactant opens future prospects for its use against micro‐organisms responsible for diseases and infections in the urinary, vaginal and gastrointestinal tracts, as well as in the skin, making it a suitable alternative to conventional antibiotics.     

Inhibition of NF-κB activation by diethylcarbamazine prevents alcohol-induced liver injury in C57BL/6 mice

Induction of NF-κB-mediated gene expression has been identified in the pathogenesis of alcoholic liver disease (ALD). Diethylcarbamazine (DEC) is a piperazine derivative drug with anti-inflammatory properties. The present study was designed to evaluate the effect of DEC on NF-κB pathways in mice undergoing alcoholism induced hepatic inflammation. Forty male C57BL/6 mice were divided equally into four groups: control group (C); DEC-treated group, which received 50 mg/kg (DEC50); alcoholic group (EtOH), submitted to chronic alcohol consumption and the alcohol-DEC treated group (EtOH50), submitted to chronic alcoholism consumption plus DEC treatment. Histological analysis of the alcoholic group showed evident hepatocellular damage which was reduced in EtOH50 group. Immunohistochemistry and western blot results showed elevated expression of inflammatory markers such as MDA, TNF-α, IL-1β, COX-2 and iNOS in hepatocytes of EtOH group. However, low immunopositivity for these markers was detected following DEC treatment. In the EtOH group the activation of NF-κB was observed by an increase in the expression of both NF-κB and pNF-κB in hepatocytes. This expression was significantly reduced in livers of EtOH50 group. Protein expression of Iκβα was measured to determine whether activation of NF-κB might be the result of Iκβα degradation. It was observed that expression of this protein was low in EtOH group, while animals treated with DEC had a high expression of Iκβα. The results of the present study indicate that DEC alleviates alcoholic liver injury, in part by the inhibiting activation of NF-κB and by suppressing the induction of NF-κB-dependent genes.