The Dependence of Crops for Pollinators and the Economic Value of Pollination in Brazil.

Food production is challenged by changes in climate and land use and expanding human population growth. Proper pollination can increase the production and quality of fruit, nut, oil, and fiber crops. We reviewed crop dependence on pollinators and estimated the economic value of pollination per year for each crop in Brazil. We analyzed 141 crops and found that 85 depend on pollinators. Almost one-third of these crops have an essential or great dependence on pollinators. The economic contribution of pollinators totals ∼30% (∼US$12 billion) of the total annual agricultural income of the dependent crops (totalizing almost US$45 billion). However, half of these figures includes soybean crop (US$5.7 billion of pollinators' contribution and US$22 billion of annual income). Soybean was considered as having a modest dependence on pollinators, but this remains controversial because pollinator dependence might vary among different varieties cultivated in Brazil. Moreover, we have no information about pollinator dependence regarding some important crops, showing the urgent need for basic research into reproductive biology and pollination ecology.

Atividade antimicrobiana dos extratos metanólicos da raiz, caule e folhas de Croton pulegioides Baill. (Zabelê) / Antimicrobial activity of methanol extracts of root, stem and leaves of Croton pulegioides Baill

O uso popular de plantas medicinais continua sendo de grande interesse para a população, principalmente em países em desenvolvimento, nos quais o acesso à medicina alopática ainda é muito restrito. Assim, além de sua importância na medicina tradicional, o conhecimento das plantas pode fornecer para a indústria farmacêutica, direta ou indiretamente, princípios ativos de interesse terapêutico. No presente trabalho foi avaliada a atividade antimicrobiana dos extratos metanólicos secos de Croton pulegioides Baill. obtidos a partir da raiz, do caule e das folhas nas concentrações de 25, 50 e 100mg/mL utilizando o método de difusão em Agar (técnica de poços) frente a cinco cepas Gram-positivas, três cepas de fungos e três cepas de bactérias Gram-negativas. Na execução do estudo foi utilizado o antibiótico Gentamicina (100µg/mL) no teste com bactérias, e Cetoconazol (300µg/mL) para as Candidas verificando-se, ao mesmo tempo, a ausência de atividade para o diluente DMSO 20% em água. Na observação dos resultados evidenciaram-se halos de inibição indicando atividade dos extratos metanólicos da raiz, caule e folhas, nas concentrações de 50 e 100mg/ml, frente Bacillus subtilis AM 04; dos extratos metanólicos da raiz e do caule, nas concentrações de 50 e 100mg/ml, frente Staphylococcus aureus AM 103 (ATCC 6538); e do extrato metanólico do caule, nas concentrações de 50 e 100mg/ml, frente S. epidermidis AM 235. Por outro lado, todos os extratos foram inativos nas concentrações avaliadas frente às bactérias Gram-negativas utilizadas no estudo (Pseudomonas aeruginosa AM 206, Escherichia coli AM 1050 e Klebsiella pneumoniae AM 410). Referente à atividade sobre fungos, os extratos metanólicos da raiz e do caule inibiram, nas três concentrações avaliadas, o crescimento de Candida tropicalis AM 1181 e C. albicans AM 1140, enquanto o extrato das folhas, inibiu o crescimento de C. tropicalis AM 1181 nas concentrações de 50 e 100mg/ml e de C. albicans AM 1140 apenas na concentração de 100mg/mL. Finalmente o extrato metanólico das folhas, na concentração de 100mg/mL, foi o único a inibir o crescimento de Candida krusei. Os resultados preliminares apresentados pelo presente trabalho sugeriram que a espécie Croton pulegioides Baill. apresentou resultados promissores quanto ao potencial antimicrobiano.

The employment of medicinal plants as a folk custom remains important to the present time, mainly in developing countries, where access to allopathic medicine is restricted. Besides their importance in traditional medicine, the knowledge on these plants can, directly or indirectly, provide information about the active ingredients involved, which may be of interest to the pharmaceutical industry. The present study evaluated the antimicrobial activity of dried methanolic extracts of Croton pulegioides Baill, extracted from its roots, stalk, and leaves, at the concentrations of 25, 50 and 100mg/ml. These were diffused in wells with an Agar medium, to which five strains of Gram-positive, three strains of fungi and three strains of Gram-negative bacteria had been added. For this study, the antibiotic Gentamicin (10µg/100µL) was used in tests with bacteria, and Ketoconazole (30µg/100µL), with Candidas. When DMSO diluted in 20% water was used, no activity was observed. The results produced evidence of inhibition halos, which indicates the activity of the methanolic extracts from the roots, stalk and leaves at the concentrations of 50 and 100 mg/ml for Bacillus subtilis AM 04; activity of the methanolic extracts from the roots and stalk at the concentrations of 50 and 100mg/ml for Staphylococcus aureus AM 103 (ATCC 6538); and activity of the methanolic extract from the stalk at the concentrations of 50 and 100mg/ml for Staphylococcus epidermidis AM 235. There was no activity in the concentrations studied for the Gram-negative bacteria (Pseudomonas aeruginosa AM 206, Escherichia coli AM 1050 and Klebsiella pneumoniae AM 410). With respect to fungal activity, the methanolic extracts from the roots and stalk inhibited Candida tropicalis AM 1181 and C. albicans AM 1140 at the three concentrations studied. The extract from the leaves inhibited the growth of C. tropicalis AM 1181 at the concentrations of 50 e 100mg/ml and C. albicans AM 1140 only at the concentration of 100mg/ml. Finally, the methanolic extract from the leaves, at the concentration of 100mg/ml, was the only one to inhibit the growth of Candida krusei. Preliminary results from this study suggest that the Croton pulegioides Baill showed promising results as a potential antimicrobial agent.

Small-angle X-ray scattering and in silico modeling approaches for the accurate functional annotation of an LysR-type transcriptional regulator.

Xylella fastidiosa is a xylem-limited, Gram-negative phytopathogen responsible for economically relevant crop diseases. Its genome was thus sequenced in an effort to characterize and understand its metabolism and pathogenic mechanisms. However, the assignment of the proper functions to the identified open reading frames (ORFs) of this pathogen was impaired due to a lack of sequence similarity in the databases. In the present work, we used small-angle X-ray scattering and in silico modeling approaches to characterize and assign a function to a predicted LysR-type transcriptional regulator in the X. fastidiosa (XfLysRL) genome. XfLysRL was predicted to be a homologue of BenM, which is a transcriptional regulator involved in the degradation pathway of aromatic compounds. Further functional assays confirmed the structural prediction because we observed that XfLysRL interacts with benzoate and cis,cis-muconic acid (also known as 2E,4E-hexa-2,4-dienedioic acid; hereafter named muconate), both of which are co-factors of BenM. In addition, we showed that the XfLysRL protein is differentially expressed during the different stages of X. fastidiosa biofilm formation and planktonic cell growth, which indicates that its expression responds to a cellular signal that is likely related to the aromatic compound degradation pathway. The assignment of the proper function to a protein is a key step toward understanding the cellular metabolic pathways and pathogenic mechanisms. In the context of X. fastidiosa, the characterization of the predicted ORFs may lead to a better understanding of the cellular pathways that are linked to its bacterial pathogenicity.

Association of CD28 and CTLA-4 gene polymorphisms with aggressive periodontitis in Brazilians.

OBJECTIVE: Susceptibility to and severity of periodontal disease is influenced by gene polymorphisms related to the immune response. Co-stimulatory molecules, such as CD28 and CTLA-4, are critical in the development of such responses. Our hypothesis is that polymorphisms in genes that code for these molecules may be associated with periodontitis. The aim of the study was to investigate the association between +17 (T/C) CD28 and +49 (A/G) CTLA-4 gene polymorphisms and periodontitis in Brazilians. MATERIALS AND METHODS: Genomic DNA was obtained from oral swabs of 424 individuals categorized into three groups (control group, aggressive, and chronic periodontitis) considering clinical parameters such as probing depth and clinical attachment loss. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There was an association between the T(-) genotype of the CD28 polymorphism and aggressive periodontitis (P = 0.04). Moreover, the A(+) genotype for CTLA-4 was associated with greater clinical attachment loss in non-smokers with aggressive periodontitis (P = 0.006, OR = 16.25, CI = 2.25-117.11). CONCLUSIONS: These findings show that T(-) in CD28 + 17 (T/C) and the A(+) in CTLA-4 +49 (A/G) genotypes are associated with susceptibility to aggressive periodontal disease. Thus, our study highlights these polymorphisms as potential genetic susceptibility markers of periodontitis in Brazilians.

Atividade antimicrobiana e sinérgica das frações das folhas de Schinopsis brasiliensis Engl. frente a clones multirresistentes de Staphylococcus aureus / Antimicrobial and synergic activity of fractions from the leaves of Schinopsis brasiliensis Engl. against Staphylococcus aureus multiresistant clones

No presente estudo objetivou-se avaliar a atividade antimicrobiana e sinérgica de 4 frações das folhas de Schinopsis brasiliensis Engl (F1', F2', F1" e F2") frente às cepas Staphylococcus aureus MRSA multirresistentes. Os métodos utilizados foram poços de difusão em ágar, concentração mínima inibitória (CMI) - diluição em ágar, e bioautografia. Nos resultados bioautográficos observou-se três halos de inibição relacionados, no mínimo, à quatro constituintes ativos; sendo dois deles isolados das folhas (galato de metila e ácido gálico). A F2" (200∝g/mL) apresentou halos de inibição de 16 e 19mm frente as cepas de S. aureus multirresistente e Klebsiella pneumoniae, e CMI 100∝g/mL, respectivamente. Quanto as análises das associações das frações F1" ou F2" (25 e 50∝g/mL) com a tetraciclina e oxacilina, mostraram ações aditiva e sinérgica para a F2" (50∝g/mL), embora não suficiente para que a CMI atingisse valores inferiores a 2 e 4∝g/mL, necessário para serem classificadas como cepas sensíveis a oxacilina e tetraciclina, respectivamente. "Assim, conclui-se que a F2" das folhas de S. brasiliensis apresentou potencial antimicrobiano frente às cepas de S. aureus MRSA multirresistentes e que as associações das frações com os antibióticos testados não apresentaram benefícios não justificando o uso concomitante.

The aim of this study was to evaluate the antimicrobial and synergic activity of 4 leaf fractions of Schinopsis brasiliensis Engl (F1', F2', F1" and F2") against multidrug-resistant Staphylococcus aureus strains. The used methods were agar well diffusion, minimum inhibitory concentration (MIC) - agar dilution, and bioautography. The bioautographic results showed three inhibition zones that corresponded to at least four active compounds, two of which (methyl gallate and gallic acid) have already been isolated from leaves. The F2" (200∝g/mL) fraction showed inhibition zones of 16 mm and 19 mm against S. aureus multidrug-resistant and Klebsiella pneumoniae strains and a MIC value of 100∝g/mL, respectively. The analyses of associations of fraction F1" or F2" (25 and 50∝g/mL) with tetracycline and oxacillin showed additive and synergistic action for F2" (50∝g/mL), although it was not enough to decrease the MIC values to less than 2 and 4∝g/mL, necessary to classify the strains as susceptible to oxacillin and tetracycline, respectively. Thus, it was concluded that F2" from the leaves of S. brasiliensis showed antimicrobial potential against multidrug-resistant MRSA strains, and the associations of the fractions with the tested antibiotics showed no benefits, not justifying their concomitant use.

Characterization of an oxidative stress response regulator, homologous to Escherichia coli OxyR, from the phytopathogen Xylella fastidiosa.

The OxyR oxidative stress transcriptional regulator is a DNA-binding protein that belongs to the LysR-type transcriptional regulators (LTTR) family. It has the ability to sense oxidative species inside the cell and to trigger the cell's response, activating the transcription of genes involved in scavenging oxidative species. In the present study, we have overexpressed, purified and characterized the predicted OxyR homologue (orf xf1273) of the phytopathogen Xylella fastidiosa. This bacterium is the causal agent of citrus variegated chlorosis (CVC) disease caused by the 9a5c strain, resulting in economic and social losses. The secondary structure of the recombinant protein was analyzed by circular dichroism. Gel filtration showed that XfoxyR is a dimer in solution. Gel shift assays indicated that it does bind to its own predicted promoter under in vitro conditions. However, considering our control experiment we cannot state that this interaction occurs in vivo. Functional complementation assays indicated that xfoxyR is able to restore the oxidative stress response in an oxyr knockout Escherichia coli strain. These results show that the predicted orfxf1273 codes for a transcriptional regulator, homologous to E. coli OxyR, involved in the oxidative stress response. This may be important for X. fastidiosa to overcome the defense mechanisms of its host during the infection and colonization processes.

Overexpression and purification of PWL2D, a mutant of the effector protein PWL2 from Magnaporthe grisea.

The rice blast disease caused by the ascomycete Magnaporthe grisea continues to cause a tremendous impact in rice (Oryza sativa) cultures around the world. Elucidating the molecular basis of the fungus interactions with its host might help increase the general understanding of the pathogen-host relationship. At the moment of invasion, the fungus secretes effectors that modify host defenses and cellular processes as they successively invade living rice cells. PWL2, an effector protein, is a known AVR (avirulence) gene product. The PWL2 gene prevents the fungus from infecting weeping lovegrass (Eragrostis curvula). In this study, we identified a PWL2 allele gene (which we termed PWL2D) in a strain of M. grisea. The sequence of PWL2D has only two bases different from that of PWL2, producing alterations in residue 90 and residue 142. However, the alteration of residue 90 (from D(90) to N(90)) is critical to gene function. Here, we cloned the gene PWL2D in a pET System vector, expressed the gene product in Escherichia coli and evaluated by spectroscopic techniques some aspects of the PWL2D structure. While TRX-tagged PWL2D is prone to aggregation, the solubility of PWL2D is improved when it is overexpressed without its original signal peptide. Expression and purification procedures for these constructs are described. Finally, we found out that the protein seems to be an intrinsically disordered protein. Results from these studies will facilitate structural analysis of PWL2D and might contribute to understanding the gene's function and of fungal/plant interactions.

Redescription of Rhabdochona anguillae (Nematoda: Rhabdochonidae), a parasite of eel, Anguilla anguilla, in Europe.

The nematode Rhabdochona anguillae Spaul, 1927, a specific intestinal parasite of the European eel, Anguilla anguilla (L.), is redescribed and illustrated from specimens collected from eels of the Sousa River, northern Portugal (prevalence 20%, intensity 2-13). The species is characterized by the presence of 14 anterior teeth in the prostom, small non-bifurcate deirids, absence of lateral preanal papillae, by the length (0.460-0.660 and 0.130-0.150 mm) and the shape of spicules, fairly large (0.041-0.054 x 0.025-0.030 mm) mature eggs without filaments, and by the bluntly pointed to rounded tip of the tail. Its morphological features are discussed in relation to other congeneric species. This nematode has hitherto been recorded only from eels in southern Europe (Portugal, Spain, Bulgaria).

Lichen planus and chronic hepatitis C: exacerbation of the lichen under interferon-alpha-2a therapy.

A 51-year-old man was treated for histologically proven chronic hepatitis C with 3 MU of recombinant interferon-alpha-2a three times a week. Before interferon therapy, a mild lichen planus (hypertrophic variant) had been diagnosed, which exacerbated within 6 weeks of treatment to a severe erosive oral form. Then interferon therapy was stopped because local measures did not improve oral lesions. However, the patient tolerated interferon therapy well, and the initially four-fold elevated aminotransferase levels returned to normal. Nine weeks after discontinuation of interferon therapy, nearly all the buccal mucous membrane lesions had disappeared. But 8 weeks after withdrawal of interferon, aminotransferase levels rose again to six times the normal range. Treating physicians should know that a pre-existing lichen planus would potentially exacerbate, as a side effect of interferon-alpha-2a therapy of chronic hepatitis. However, further observations are needed to decide its clinical relevance.

[The endocrine pancreas]. / Pâncreas endócrino.

The islets of Langerhans provide energy storage and disposal, and protection from plasma glucose excursions, especially hypoglycemia. Insulin-dependent diabetes mellitus (IDDM) results from autoimmune beta-cell damage. Prevention of IDDM has already been achieved in animal investigation and some centers are now screening and treating individuals at high risk for developing IDDM. Immunosuppressive drugs can induce transient remission of recent-onset IDDM. Intensive insulin treatment of IDDM delays the onset and slows the progression of long-term complications. Non-insulin dependent diabetes mellitus (NIDDM) is the result of beta-cell malfunction and is strongly associated with X syndrome. Diet and exercise are of undoubted importance in NIDDM prevention and treatment. Functional endocrine tumors of the pancreas (FET) are rare hormone and peptide-secreting neoplasms. These peptides may or may not occur naturally in the islets. FETs often occur with multiple endocrine neoplasia 1 (MEN 1) so that MEN-1 screening should always be performed, and extended to family members whenever diagnosed. Drugs--alcohol, insulin and sulfonilureas--are the main cause of hypoglycemia. Insulinoma is the main cause of post-absorptive organic hypoglycemia. Non islet-cell tumors seldom cause hypoglycemia. Insulinoma often is a solitary tumor, but it may be multicentric and may coexist with cell hyperplasia and nesidioblastosis. Symptoms of neuroglycopenia may be mistaken for neuropsychiatric disease. The diagnosis is based on confirmation of post absorptive hypoglycemia and hyperinsulinism. Gastrinoma causes Zollinger-Ellison syndrome (ZES) which is characterized by fulminating peptic ulcer disease. The tumor is often malignant, and it may be multicentric and may occur with cell hyperplasia and nesidioblastosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anal tonometry: a quick method of anal manometry.

Evaluation of anal sphincter tonic activity is important in the proctologic clinic. However, manometric techniques are expensive, complex, and only available in some centers. Because there is often an in-office need for having objective measurements of anal tonic activity, in our clinic we introduced a simple method for measurement of anal pressures. This method is based on the flow of air in an open circuit by using a rubber probe with a side opening at one end. Pressure is assessed by an ordinary manometric gauge for arterial pressure. With this simple instrument, the following parameters are measured: 1) anal resting pressure, 2) squeeze pressure, 3) functional length of the anal canal, and 4) descent of the perineum on staining. After testing the technique in 100 healthy persons, it was applied to 130 patients with several proctologic disorders. Differences in pressures were found between controls and patients with anal fissure (high resting pressures), and patients with anal incontinence (low resting and/or squeeze pressures). A correlation was also found between the descending perineum measured by this method and by defecography. This simple instrument is useful in the office as the first approach to the function of the anal sphincters and the pelvic floor. Nowadays, so-called anal tonometry is part of the proctologic examination in our department, because it is simple, reliable, and takes only a few minutes.

[Biguanides in the treatment of diabetes mellitus]. / As biguanidas na terapêutica da diabetes.

Biguanides are useful drugs in diabetes but their indications are very precise. The danger of lactic acidosis can be avoided with the use of metformin, the less toxic of biguanides, and strict respect for contraindications. All biguanides have a similar action, through different pharmacokinetics, and besides their hypoglycemic effect, have a favourable action on blood lipids, which increases their usefulness. Haemorheological effects, recently studied in animal research, may open a new field in the employment of biguanides.