Predation of bat (Molossus molossus: Molossidae) by the centipede Scolopendra viridicornis (Scolopendridae) in Southern Amazonia

Centipedes are opportunistic carnivore predators, and large species can feed on a wide variety of vertebrates, including bats. The aim of this study was to report the third record of bat predation by centipedes worldwide, the first record in the Amazon region, while covering aspects of foraging, capture and handling of prey. We observed the occurence in a fortuitous encounter at Cristalino State Park, located in the Amazon region of the state of Mato Grosso, Brazil. The attack took place in a small wooden structure, at about three meters from the floor, and was observed for 20 minutes. During the observation, the centipede stung the neck and abdominal region of the bat several times, grabbing the prey with its 15 pairs of front legs while hanging from the ceiling with its hind legs. This type of observation suggests that vertebrates can be important preys for invertebrates such as giant centipedes, both for its nutritional composition and for the amount of energy available in a single prey.

Hematological responses of tambaqui Colossoma macropomum (Serrassalmidae) fed with diets supplemented with essential oil from Mentha piperita (Lamiaceae) and challenged with Aeromonas hydrophila

ABSTRACTIn fish farmings, diseases can be reduced by using immunostimulants. The aim of this study was to evaluate the immunostimulant potential of Mentha piperita in tambaqui fed with 0, 0.5, 1.0 and 1.5% of oil per kg of commercial fish feed. The fish were inoculated with Aeromonas hydrophila to challenge them. Hematological and biochemical parameters were determined after 30 days of feeding and seven days after the challenge. There was no mortality and M. piperita oil did not influence fish production parameters. However, blood hemoglobin concentration (Hb) increased in the fish fed with 0.5 and 1.5% of oil per kg of diet; albumin increased in those fed with 1.0%; cholesterol increased in all groups with oil; and triglycerides increased in those fed with 0.5%. After the bacterial challenge, the fish showed decreases in Hb when fed with diet enriched with 1.5% oil per kg of diet, in mean corpuscular volume with 1.0% and in mean corpuscular hemoglobin concentration with 0 and 1.5%. Protein levels increased in groups with 0 and 1.5% of oil and albumin when fed with 0 and 1.0%; cholesterol levels increased in the control group; and high levels of triglycerides were observed in the groups with 0, 0.5 and 1.5%. Thus, M. piperita essential oil promoted hematological alterations in tambaqui and can be recommended in diets containing up to 1.0% per kg, because of the minimal physiological modifications caused. However, additional studies are necessary to obtain more information regarding to the physiological effects of this immunostimulant.

The relevance of bacterial interactions on oral health

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

Nanocomposites: the contribution of multiscale modelling to improve the dispersion levels

Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos

“PhenoWorld”: a new multidimensional strategy for studying behaviour in rodents

Tese de Doutoramento em Ciências da Saúde

Polyphasic approach including MALDI-TOF MS/MS analysis for identification and characterisation of Fusarium verticillioides in Brazilian corn kernels

Fusarium verticillioides is considered one of the most important global sources of fumonisin contamination in food and feed. Corn is one of the main commodities produced in the Northeastern Region of Brazil. The present study investigated potential mycotoxigenic fungal strains belonging to the F. verticillioides species isolated from corn kernels in 3 different Regions of the Brazilian State of Pernambuco. A polyphasic approach including classical taxonomy, molecular biology, MALDI-TOF MS and MALDI-TOF MS/MS for the identification and characterisation of the F. verticillioides strains was used. Sixty F. verticillioides strains were isolated and successfully identified by classical morphology, proteomic profiles of MALDI-TOF MS, and by molecular biology using the species-specific primers VERT-1 and VERT-2. FUM1 gene was further detected for all the 60 F. verticillioides by using the primers VERTF-1 and VERTF-2 and through the amplification profiles of the ISSR regions using the primers (GTG)5 and (GACA)4. Results obtained from molecular analysis shown a low genetic variability among these isolates from the different geographical regions. All of the 60 F. verticillioides isolates assessed by MALDI-TOF MS/MS presented ion peaks with the molecular mass of the fumonisin B1 (721.83 g/mol) and B2 (705.83 g/mol)

Evaluation of zearalenone in vitro removal by Saccharomyces cerevisiae strains isolated from bovine forage

Zearalenone (ZEN) is a mycotoxin that has relatively low acute toxicity. However, it is a potent oestrogen, interfering with the reproductive tract of animals. Among other effects, ZEN decreases animals fertility, and induces fibrosis in the uterus, breast cancer and endometrial carcinoma (Zinedine et al., 2007). Anti-mycotoxin additives (AMA) are defined as a group of products that, when added to animal feed, are capable of adsorbing, inactivating, or neutralizing mycotoxins in the gastrointestinal tract of animals. One example of these products are adsorbents based on yeast cell walls, a safe and beneficial animal feed additive (Abreu et al., 2008). When based on active cells, yeast based products also act as a probiotic, contributing to improve the general animal health because it stimulates their immune system and promotes the integrity of intestinal mucosa (Albino et al., 2006). Strains of Saccharomyces cerevisiae isolated from silage were tested for their ZEN removal capability. Their effect on - and b-zearalenol (-ZOL and b-ZOL) was also tested. Strains were grown on YPD separately supplemented with ZEN, -ZOL and b-ZOL, and their elimination from culture media was quantified over time by HPLC-FL.

Extraction and characterization of polysaccharides from non-traditional Brazilian Amazon sources

[Excerpt] Cupuassu (Theobroma grandiflorum), tucumã (Astrocaryum aculeatum), peach palm (Bactris gasipaes) and abricó (American Mammea L.) are exotic fruits found in the Brazilian Amazon rainforest. All of them are well known by the native populations, and for centuries the pulps have been used in the production of juices, deserts, jams, syrups, and alcoholic beverages, among others. Additionally, the fruit seeds have been used as animal feed, fertilizers or to plant new seedlings, but a great part of these seeds are usually discarded. (...)

Aflatoxins detoxification by gamma irradiation

[Excerpt] Mycotoxins are secondary toxic metabolites of filamentous fungi. Aflatoxins (AFs) are produced to Aspergillus species such as A. flavus and A. parasiticus. These fungi are ubiquitous in nature and usually found on agricultural commodities. Therefore, AFs are encountered in many important foodstuff, including wheat, rice, maize, peanuts, sorghum, pearl millet, spices, oilseeds, tree nuts and milk. Due to the high toxicity of AFs, many methods have been studied to reduce or eliminate these mycotoxins from food and feed. Gamma irradiation is one technology that has been investigated with promising results. The aims of this study were (I) to study the effect of gamma radiation on aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 (II) to evaluate the effect of the presence of water on AFs degradation during the irradiation process; and (IV) to evaluate the cytotoxicity of radiolytic products formed. (...)

Current situation on the occurrence of mycotoxins and toxigenic fungi in Portugal

Mycotoxins are secondary metabolites produced by filamentous fungi that are toxic for humans and animals in small amounts and that are found worldwide in a large number of agricultural commodities. They are usually ingested involuntarily, when contaminated plant products are consumed, and represent a great risk for public health. Therefore, governments throughout the world have imposed strict legal limits for their levels in food and feed products in order to reduce potential health risks for consumers. Despite of its ubiquity, the mycotoxin problem is mainly dependent on regional factors, such as the mycotoxigenic characteristics of the local mycoflora, the local climate conditions, and the local agricultural practices. For this reason, a constant vigilance from local governmental food safety agencies and from the local researcher community is needed. This communication will review the current situation on the occurrence of mycotoxigenic fungi in some Portuguese cultures, such as wine grapes, corn and dried fruits. Particular attention will be given to the incidence of mycotoxigenic Aspergillus strains in those cultures and to the levels of ochratoxin A, aflatoxins, cyclopiazonic acid and fumonisin B2 produced. Data will be discussed taking into account the geographical origin of the isolates and the particular climate conditions of each sampling region. An updated review on the levels of the main mycotoxins found in local products and in imported commodities will also be presented.

Simultaneous detection of cyclopiazonic acid and aflatoxin B1 by HPLC in methanol/water mobile phase

A simple procedure for the simultaneous detection of cyclopiazonic acid (CPA) and aflatoxin B1 from fungal extracts is presented, using a methanol and water mobile phase and fluorescence detection. This methodology has been tested with standard solutions of both mycotoxins CPA and Aflatoxin B1 and with methanolic extracts of Aspergillus section Flavi strains, previously characterized for their mycotoxin production profile. Previously available methodology required the use of two different chromatographic runs for these mycotoxins, with distinct columns and detectors (fluorescence detection with a post-column photochemical derivatization (PHRED) for aflatoxin B1 and UV detection for CPA). The proposed method detects both mycotoxins in a single run. Data from these assays will be presented and discussed.

The isolation of Aspergillus spp from harvested maize in three Portuguese regions

In Portugal, maize is the cereal that involves more agriculture explorations. Aspergillus spp., among other species, are usually associated with this cereal, during drying and storage, making this commodity susceptible to mycotoxins (such as aflatoxins, ochratoxins, and cyclopiazonic acid). The aim of this study was to evaluate the mycotoxigenic potential of isolated Aspergillus strains from these maize samples and correlate it with the sampling place, the weather conditions, and local practices during drying and storage. The samples were collected between November 2008 and April 2009 in maize association of producers facilities in Coimbra, Santarém and Portalegre. The isolated strains were divided in three distinct groups, Aspergillus section Flavi, Aspergillus section Nigri and others Aspergillus. The preliminary results show that there are differences between the incidence of these groups in the three sampling places, especially in Coimbra, probably due to a lower mean temperatures and higher humidity levels. These data will be presented and discussed.

Enzymes which detoxify ochratoxin A

Mycotoxins are fungal secondary metabolites found in some agricultural commodities which are toxic for humans and animals in small amounts. Mycotoxins are a global problem which can be partially controlled through prevention strategies that can be applied along the food and feed chain production. However, when mycotoxin formation can not be avoided and they come to be present in commodities some remediation strategies can also be used to reduce its levels on products, its bioavailability or its toxic effects. Among these remediation strategies, the biological methods are recently holding a relevant position, being widely studied in the last years. As a result, a great number of microorganisms that can degrade or detoxify several mycotoxins and the application of some of them were reported. Moreover, several enzymes which mediate these biological processes were identified, being by themselves studied in order to develop new biotechnological approaches to control the mycotoxin problem on commodities. The main enzymes known to detoxify ochratoxin A, their action and their present application in order to counteract the referred problem are reviewed and critically assessed.

New bio-strategies for ochratoxin A detoxification using lactic acid bacteria

The occurrence of mycotoxigenic moulds such as Aspergillus, Penicillium and Fusarium in food and feed has an important impact on public health, by the appearance of acute and chronic mycotoxicoses in humans and animals, which is more severe in the developing countries due to lack of food security, poverty and malnutrition. This mould contamination also constitutes a major economic problem due the lost of crop production. A great variety of filamentous fungi is able to produce highly toxic secondary metabolites known as mycotoxins. Most of the mycotoxins are carcinogenic, mutagenic, neurotoxic and immunosuppressive, being ochratoxin A (OTA) one of the most important. OTA is toxic to animals and humans, mainly due to its nephrotoxic properties. Several approaches have been developed for decontamination of mycotoxins in foods, such as, prevention of contamination, biodegradation of mycotoxins-containing food and feed with microorganisms or enzymes and inhibition or absorption of mycotoxin content of consumed food into the digestive tract. Some group of Gram-positive bacteria named lactic acid bacteria (LAB) are able to release some molecules that can influence the mould growth, improving the shelf life of many fermented products and reducing health risks due to exposure to mycotoxins. Some LAB are capable of mycotoxin detoxification. Recently our group was the first to describe the ability of LAB strains to biodegrade OTA, more specifically, Pediococcus parvulus strains isolated from Douro wines. The pathway of this biodegradation was identified previously in other microorganisms. OTA can be degraded through the hydrolysis of the amide bond that links the L-β-phenylalanine molecule to the ochratoxin alpha (OTα) a non toxic compound. It is known that some peptidases from different origins can mediate the hydrolysis reaction like, carboxypeptidase A an enzyme from the bovine pancreas, a commercial lipase and several commercial proteases. So, we wanted to have a better understanding of this OTA degradation process when LAB are involved and identify which molecules where present in this process. For achieving our aim we used some bioinformatics tools (BLAST, CLUSTALX2, CLC Sequence Viewer 7, Finch TV). We also designed specific primers and realized gene specific PCR. The template DNA used came from LAB strains samples of our previous work, and other DNA LAB strains isolated from elderberry fruit, silage, milk and sausages. Through the employment of bioinformatics tools it was possible to identify several proteins belonging to the carboxypeptidase family that participate in the process of OTA degradation, such as serine type D-Ala-D-Ala carboxypeptidase and membrane carboxypeptidase. In conclusions, this work has identified carboxypeptidase proteins being one of the molecules present in the OTA degradation process when LAB are involved.

Bio-detoxification of mycotoxins by lactic acid bacteria from different food matrices

Lactic acid bacteria (LAB) play a key role in the biopreservation of a wide range of fermented food products, such as yogurt, cheese, fermented milks, meat, fish, vegetables (sauerkraut, olives and pickles), certain beer brands, wines and silage, allowing their safe consumption, which gave to these bacteria a GRAS (Generally Recognised as Safe) status. Besides that, the use of LAB in food and feed is a promising strategy to reduce the exposure to dietary mycotoxins, improving their shelf life and reducing health risks, given the unique mycotoxin decontaminating characteristic of some LAB. Mycotoxins present carcinogenic, mutagenic, teratogenic, neurotoxic and immunosuppressive effects over animals and Humans, being the most important ochratoxin A (OTA), aflatoxins (AFB1), trichothecenes, zearalenone (ZEA), fumonisin (FUM) and patulin. In a previous work of our group it was observed OTA biodegradation by some strains of Pediococcus parvulus isolated from Douro wines. So, the aim of this study was to enlarge the screening of the biodetoxification over more mycotoxins besides OTA, including AFB1, and ZEA. This ability was checked in a collection of LAB isolated from vegetable (wine, olives, fruits and silage) and animal (milk and dairy products, sausages) sources. All LAB strains were characterized phenotypically (Gram, catalase) and genotypically. Molecular characterisation of all LAB strains was performed using genomic fingerprinting by MSP- PCR with (GTG)5 and csM13 primers. The identification of the isolates was confirmed by 16S rDNA sequencing. To study the ability of LAB strains to degrade OTA, AFB1 and ZEA, a MRS broth medium was supplemented with 2.0 g/mL of each mycotoxin. For each strain, 2 mL of MRS supplemented with the mycotoxins was inoculated in triplicate with 109 CFU/mL. The culture media and bacterial cells were extracted by the addition of an equal volume of acetonitrile/methanol/acetic acid (78:20:2 v/v/v) to the culture tubes. A 2 mL sample was then collected and filtered into a clean 2 mL vial using PP filters with 0.45 m pores. The samples were preserved at 4 °C until HPLC analysis. Among LAB tested, 10 strains isolated from milk were able to eliminate AFB1, belonging to Lactobacillus casei (7), Lb. paracasei (1), Lb. plantarum (1) and 1 to Leuconostoc mesenteroides. Two strains of Enterococcus faecium and one of Ec. faecalis from sausage eliminated ZEA. Concerning to strains of vegetal origin, one Lb. plantarum isolated from elderberry fruit, one Lb. buchnerii and one Lb. parafarraginis both isolated from silage eliminated ZEA. Other 2 strains of Lb. plantarum from silage were able to degrade both ZEA and OTA, and 1 Lb. buchnerii showed activity over AFB1. These enzymatic activities were also verified genotypically through specific gene PCR and posteriorly confirmed by sequencing analysis. In conclusion, due the ability of some strains of LAB isolated from different sources to eliminate OTA, AFB1 and ZEA one can recognize their potential biotechnological application to reduce the health hazards associated with these mycotoxins. They may be suitable as silage inoculants or as feed additives or even in food industry.