Does the local availability of woody Caatinga plants (Northeastern Brazil) explain their use value?

This study investigated the use of woody plants by a rural community in an area of dry land Caatinga vegetation in northeastern Brazil. Information was obtained concerning this woody species with a diameter that is equal to or greater than 3 centimeters (cm) at soil level surveyed in 100 sample plots totaling 1 hectare (ha). The following question is the hypothesis we tested. Is a plant’s relative importance (as measured by its use value) related to its “apparency,” as measured by its abundance and ecological dominance? “Apparency” explains the use value of plants in four categories: medicinal, construction, fuel, and technology. The most important uses of woody plants are related to harvesting for energy and construction purposes.     

Type I interferons and MAVS signaling are necessary for tissue resident memory CD8+ T cell responses to RSV infection

Respiratory syncytial virus (RSV) can cause bronchiolitis and viral pneumonia in young children and the elderly. Lack of vaccines and recurrence of RSV infection indicate the difficulty in eliciting protective memory immune responses. Tissue resident memory T cells (T_RM) can confer protection from pathogen re-infection and, in human experimental RSV infection, the presence of lung CD8⁺ T_RM cells correlates with a better outcome. However, the requirements for generating and maintaining lung T_RM cells during RSV infection are not fully understood. Here, we use mouse models to assess the impact of innate immune response determinants in the generation and subsequent expansion of the T_RM cell pool during RSV infection. We show that CD8⁺ T_RM cells expand independently from systemic CD8⁺ T cells after RSV re-infection. Re-infected MAVS and MyD88/TRIF deficient mice, lacking key components involved in innate immune recognition of RSV and induction of type I interferons (IFN-α/β), display impaired expansion of CD8⁺ T_RM cells and reduction in antigen specific production of granzyme B and IFN-γ. IFN-α treatment of MAVS deficient mice during primary RSV infection restored T_RM cell expansion upon re-challenge but failed to recover T_RM cell functionality. Our data reveal how innate immunity, including the axis controlling type I IFN induction, instructs and regulates CD8⁺ T_RM cell responses to RSV infection, suggesting possible mechanisms for therapeutic intervention.     

Apoptosis and production of TNF-α by tumor-associated inflammatory cells in histological grade III breast cancer

Tumor necrosis factor alpha (TNF-) is a cytokine that acts as an important mediator of the apoptotic process that also demonstrates selective citotoxicity against malignant breast tumor cells. In the present study, the presence of apoptotic tumor cells and the synthesis of TNF- by inflammatory cells were investigated in tissue samples from grade III invasive breast cancer with long-term follow-up. In situ detection of tumor apoptotic cells was investigated by direct immuno-peroxidase of digoxigenin-labeled genomic DNA. The production of TNF- and tumor cell proliferation were investigated by immunohistochemical procedures. Our data demonstrated that patients with a clinical history of cancer recurrence and metastasis presented a lower number of cancerous apoptotic cells, higher tumor proliferation rates, and lower TNF- expression rates by inflammatory cells than what is observed among patients diagnosed with the same histopathological breast cancer type but in the absence of tumor recurrence and metastasis.     

Endoparasites observed within invertebrates used as live food items for captive wild birds: Overview and potential risks

To monitor and evaluate potential risks to birds’ health, invertebrate species that have been used as live food items had their body contents searched for endoparasites. The contents of approximately 10,000 invertebrates were analyzed. A principal component analysis was performed to study the relationship between the presence/absence of endoparasites and the characteristics of the invertebrates. In most of them, including the species preferred by birds such as caterpillars, waxworms, mealworms, most grasshoppers, and spiders, no organism was identified. Such findings suggest a low potential for parasite transmission associated with its consumption by birds. Although they had unknown or even unlikely implications for the birds’ health, gregarines, oxyurides Leidynema sp., and digenetic trematodes Monolecithotrema sp. were found in samples from woodlice, cockroaches, and centipedes, respectively. The only avian parasites observed in this study were Heterakis gallinarum in samples from earthworms and Acuaria spiralis from woodlice. Suggestively, soil invertebrates showed a higher prevalence of endoparasites and may represent a higher potential risk in comparison to the other categories of invertebrates sampled herein. Detritivory and collected origin were also explanatory variables related to the presence of endoparasites in the current study.     

Transgene transmission in South American catfish (<Emphasis Type="Italic">Rhamdia quelen</Emphasis>) larvae by sperm-mediated gene transfer

The silver catfish (Rhamdia quelen) is an endemic American fish species. The sperm of each species has its own peculiarities and biological characteristics, which influence the success of mass DNA transfer methods. Our objective in this study was to evaluate different sperm-mediated gene transfer (SMGT) methods to obtain transgenic silver catfish. Different treatments for the incorporation of a foreign pEGFP plasmid group were used: (1) dehydrated/rehydrated (DR), (2) dehydrated/rehydrated/electroporated (DRE), (3) electroporated (E), (4) incubated with seminal plasma (INC); and (5) incubated in the absence of seminal plasma (INCSP). Sperm motility, time of activity duration (TAD), fertilization rate (FR), hatching rate (HR) and sperm morphology were also evaluated. The polymerase chain reaction (PCR) positivity rates for the presence of the transgene were: DRE 60%; DR 40%; E 25%; INC 5% and INCSP 25%. The rates of embryo EGFP expression were: DRE 63%; DR 44%; E 34%; INC 8% and INCSP 38%. The fertilization rate in the control and DRE treatments groups were higher than in the DR group, but the E, INC and INCSP treatment groups had the lowest rate. The hatching rates of the DRE, DR and control groups were higher than in the INCSP, INC and E treatment groups (P>0.05). There were no differences among the DRE and DR, E and DR, E and INCSP groups in expression and PCR positivity rates of enhanced green fluorescent protein (EGFP) in embryos. Scanning electron microscopy also did not show any change in sperm morphology among treatment groups. To the best of our knowledge, this is the first report on transgene transmission of exogenous DNA into silver catfish larvae through SMGT technology.     

Oxidative stress induced by prenatal LPS leads to endothelial dysfunction and renal haemodynamic changes through angiotensin II/NADPH oxidase pathway: Prevention by early treatment with α-tocopherol

We investigated whether hypertension induced by maternal lipopolysaccharide (LPS) administration during gestation is linked to peripheral vascular and renal hemodynamic regulation, through angiotensin II?→?NADPH-oxidase signalling, and whether these changes are directly linked to intrauterine oxidative stress. Female Wistar rats were submitted to LPS, in the absence or presence of α-tocopherol during pregnancy. Malondialdehyde in placenta and in livers from dams and foetuses was enhanced by LPS. Tail-cuff systolic blood pressure (tcSBP) was elevated in the 16-week-old LPS offspring. Renal malondialdeyde and protein expression of NADPH oxidase isoform 2 were elevated in these animals at 20?weeks of age. Maternal α-tocopherol treatment prevented the elevation in malondialdehyde induced by LPS on placenta and livers from dams and foetuses, as well as prevented the elevation in tcSBP and the elevation in renal malondialdehyde in adult life. LPS offspring presented impairment of endothelium-dependent relaxation in aorta and mesenteric rings, which was blunted by angiotensin type 1 receptor (AT₁R) blockade and NADPH oxidase inhibition. At age of 32?weeks, renal hemodynamic parameters were unchanged in anaesthetised LPS offspring, but angiotensin II infusion led to an increased glomerular filtration rate paralleled by filtration fraction elevation. The renal haemodynamic changes provoked by angiotensin II was prevented by early treatment with α-tocopherol and by late treatment with NADPH oxidase inhibitor. These results point to oxidative stress as a mediator of offspring hypertension programmed by maternal inflammation and to the angiotensin II?→?NADPH oxidase signalling pathway as accountable for vascular and renal dysfunctions that starts and maintains hypertension.     

Organic Codes: A Unifying Concept for Life

Although the knowledge about biological systems has advanced exponentially in recent decades, it is surprising to realize that the very definition of Life keeps presenting theoretical challenges. Even if several lines of reasoning seek to identify the essence of life phenomenon, most of these thoughts contain fundamental problem in their basic conceptual structure. Most concepts fail to identify either necessary or sufficient features to define life. Here, we analyzed the main conceptual frameworks regarding theoretical aspects that have been supporting the most accepted concepts of life, such as (i) the physical, (ii) the cellular and (iii) the molecular approaches. Based on an ontological analysis, we propose that Life should not be positioned under the ontological category of Matter. Yet, life should be better understood under the top-level ontology of “Process”. Exercising an epistemological approach, we propose that the essential characteristic that pervades each and every living being is the presence of organic codes. Therefore, we explore theories in biosemiotics and code biology in order to propose a clear concept of life as a macrocode composed by multiple inter-related coding layers. This way, as life is a sort of metaphysical process of encoding, the living beings became the molecular materialization of that process. From the proposed concept, we show that the evolutionary process is a fundamental characteristic for life’s maintenance but it is not necessary to define life, as many organisms are clearly alive but they do not participate in the evolutionary process (such as infertile hybrids). The current proposition opens a fertile field of debate in astrobiology, epistemology, biosemiotics, code biology and robotics.

     

Distribution and content of calcium and potassium in eucalyptus leaves infected with Calonectria pteridis

Calonectria leaf spot, caused by Calonectria pteridis, is a serious problem in Eucalyptus crops in both nursery and the field. Under ideal conditions, the disease can cause severe defoliation. It is known that calcium and potassium are directly related to the plant's resistance to pathogens. Thus, the knowledge of how a balanced fertilization of Ca and K interferes in the distribution of these nutrients at the infection site would contribute to elucidate the resistance of the plant related to its nutrition. This study investigated the effect of calcium and potassium fertilizer application on the content and distribution of these nutrients in the symptomatic leaf area, transition zone and asymptomatic leaf area over time. Eucalyptus seedlings were grown in nutrient solution under different Ca and K treatments (6 mmol/L K + 4 mmol/L Ca, 6 mmol/L K + 8 mmol/L Ca and 9 mmol/L K + 12 mmol/L Ca) and inoculated with C. pteridis. Leaves were removed at 24, 48 and 72 hr after inoculation (hai) and evaluated by X-ray microanalysis. The highest calcium content among the different leaf areas was observed in the symptomatic area, and the levels in this area increased over time, with the highest mean value observed at 72 hai in the 6K + 8Ca treatment. In the other treatments, the mean calcium content peaked at 48 hai and then decreased. A similar pattern in asymptomatic tissue was observed for potassium in the 6K + 8Ca treatment. Fertilization with calcium and potassium directly affected the demand and availability of nutrients at different times during infection. These results demonstrate that plant defence responses and their continuity over time during infection rely on balanced calcium and potassium fertilization because these nutrients are directly involved in plant resistance to the pathogen.     

Denaturant-induced unfolding of the acetyl-esterase from Escherichia coli

The stability of acetyl-esterase, Aes, from Escherichia coli against the denaturing action of urea and guanidine hydrochloride, GuHCl, has been investigated by means of circular dichroism and fluorescence measurements. The urea-induced unfolding curves show a single inflection point at 6.2 M urea, whereas the GuHCl-induced curves show two inflection points at 1.4 and 3.1 M GuHCl. The unfolding process is reversible with both urea and GuHCl. These results, together with similar experimental data on the mutant form V20D-Aes, suggest the presence of two domains in the Aes structure, which unfold more or less independently depending on the denaturant used. This is also supported by a 3D model obtained by homology modeling using the structure of brefeldine as a template. The effect of NaCl on the urea-induced unfolding curves of the enzyme has also been investigated.