Anaplasma marginale infection in cattle from south-western Amazonia

The present study provides the first epidemiological data regarding infection by Anaplasma marginale in cattle reared in south-western Brazilian Amazonia. One simple procedure was adapted for the extraction of DNA from blood clots collected in seven microregions of Rondônia State and two mesoregions of Acre State. PCR method was used to asses the frequency of A. marginale infections in 4 to12-month-old cattle. The cattle infection was investigated by polymerase chain reaction (PCR) using the specific primer "msp5" for A. marginale. The DNA amplifications revealed that the mean frequency of A. marginale infection was 98.6% (1,627/1,650) in samples from Rondonia, and 92.87% (208/225) in samples from Acre. The high frequency of A. marginale infections in 4 to 12-month-old cattle indicate a situation of enzootic stability in the studied areas and are comparable to those detected by immunodiagnosis in different endemic regions in Brazil. The DNA extraction of clotted blood method described here can be used for epidemiological studies on anaplasmosis and other bovine hemoparasites.

Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR

The current systems of breeding poultry, based on high population density, increase the risk of spreading pathogens, especially those causing respiratory diseases and those that have more than one host. Fowl Cholera (FC) is one such pathogen, and even though it represents one of several avian diseases that should be considered in the differential diagnosis of notifiable diseases that present with sudden death, the pathogenesis and virulence factors involved in FC are still poorly understood. The objective of this study was to investigate twelve genes related to virulence in 25 samples of Pasteurella multocida isolated from FC cases in the southern region of Brazil through the development of multiplex PCR protocols. The protocols developed were capable of detecting all of the proposed genes. The ompH, oma87, sodC, hgbA, hgbB, exBD-tonB and nanB genes were present in 100% of the samples (25/25), the sodA and nanH genes were present in 96% (24/25), ptfA was present in 92% (23/25), and pfhA was present in 60% (15/25). Gene toxA was not identified in any of the samples studied (0/25). Five different genetic profiles were obtained, of which P1 (negative to toxA) was the most common. We concluded that the multiplex-PCR protocols could be useful tools for rapid and simultaneous detection of virulence genes. Despite the high frequency of the analyzed genes and the fact that all samples belonged to the same subspecies of P. multocida, five genetic profiles were observed, which should be confirmed in a study with a larger number of samples.

Identification and antimicrobial resistance of members from the Enterobacteriaceae family isolated from canaries (Serinus canaria)

Abstract: The Enterobacteriaceae family contains potentially zoonotic bacteria, and their presence in canaries is often reported, though the current status of these in bird flocks is unknown. Therefore, this study aimed to identify the most common genera of enterobacteria from canaries (Serinus canaria) and their antimicrobial resistance profiles. From February to June of 2013, a total of 387 cloacal swab samples from eight domiciliary breeding locations of Fortaleza city, Brazil, were collected and 58 necropsies were performed in canaries, which belonged to the Laboratory of Ornithological Studies. The samples were submitted to microbiological procedure using buffered peptone water and MacConkey agar. Colonies were selected according to their morphological characteristics on selective agar and submitted for biochemical identification and antimicrobial susceptibility. A total of 61 isolates were obtained, of which 42 were from cloacal swabs and 19 from necropsies. The most isolated bacteria was Escherichia coli with twenty five strains, followed by fourteen Klebsiellaspp., twelve Enterobacterspp., seven Pantoea agglomerans, two Serratiaspp. and one Proteus mirabilis. The antimicrobial to which the strains presented most resistance was sulfonamides with 55.7%, followed by ampicillin with 54.1% and tetracycline with 39.3%. The total of multidrug-resistant bacteria (MDR) was 34 (55.7%). In conclusion, canaries harbor members of the Enterobacteriaceae family and common strains present a high antimicrobial resistance rate, with a high frequency of MDR bacteria.

Vibration analysis for Bearing outer race condition diagnostics

This paper investigates defect detection methodologies for rolling element bearings through vibration analysis. Specifically, the utility of a new signal processing scheme combining the High Frequency Resonance Technique (HFRT) and Adaptive Line Enhancer (ALE) is investigated. The accelerometer is used to acquire data for this analysis, and experimental results have been obtained for outer race defects. Results show the potential effectiveness of the signal processing technique to determine both the severity and location of a defect. The HFRT utilizes the fact that much of the energy resulting from a defect impact manifests itself in the higher resonant frequencies of a system. Demodulation of these frequency bands through use of the envelope technique is then employed to gain further insight into the nature of the defect while further increasing the signal to noise ratio. If periodic, the defect frequency is then present in the spectra of the enveloped signal. The ALE is used to enhance the envelope spectrum by reducing the broadband noise. It provides an enhanced envelope spectrum with clear peaks at the harmonics of a characteristic defect frequency. It is implemented by using a delayed version of the signal and the signal itself to decorrelate the wideband noise. This noise is then rejected by the adaptive filter that is based upon the periodic information in the signal. Results have been obtained for outer race defects. They show the effectiveness of the methodology to determine both the severity and location of a defect. In two instances, a linear relationship between signal characteristics and defect size is indicated.

Power-line-communication-based data transmission concept for an LVDC electricity distribution network – Analysis and implementation

Communications play a key role in modern smart grids. New functionalities that make the grids ‘smart’ require the communication network to function properly. Data transmission between intelligent electric devices (IEDs) in the rectifier and the customer-end inverters (CEIs) used for power conversion is also required in the smart grid concept of the low-voltage direct current (LVDC) distribution network. Smart grid applications, such as smart metering, demand side management (DSM), and grid protection applied with communications are all installed in the LVDC system. Thus, besides remote connection to the databases of the grid operators, a local communication network in the LVDC network is needed. One solution applied to implement the communication medium in power distribution grids is power line communication (PLC). There are power cables in the distribution grids, and hence, they may be applied as a communication channel for the distribution-level data. This doctoral thesis proposes an IP-based high-frequency (HF) band PLC data transmission concept for the LVDC network. A general method to implement the Ethernet-based PLC concept between the public distribution rectifier and the customerend inverters in the LVDC grid is introduced. Low-voltage cables are studied as the communication channel in the frequency band of 100 kHz–30 MHz. The communication channel characteristics and the noise in the channel are described. All individual components in the channel are presented in detail, and a channel model, comprising models for each channel component is developed and verified by measurements. The channel noise is also studied by measurements. Theoretical signalto- noise ratio (SNR) and channel capacity analyses and practical data transmission tests are carried out to evaluate the applicability of the PLC concept against the requirements set by the smart grid applications in the LVDC system. The main results concerning the applicability of the PLC concept and its limitations are presented, and suggestion for future research proposed.

Aktiivisen verkkosillan tuottaman yhteismuotoisen jännitteen vaimentaminen kaksitasoisessa, jännitevälipiirillisessä, taajuusmuuttajatopologiassa

Pulssinleveysmoduloidun vaihtosuuntaajan hyötysuhteen parantaminen ja kytkentätaajuuden suurentaminen ovat johtaneet lähtöjännitteen suuritaajuiseen taajuussisältöön kaksitasoisessa, jännitevälipiirillisessä taajuusmuuttajatopologiassa. Kasvava tarve siirtää tehoa myös verkkoon päin on lisännyt aktiivisen verkkosillan käyttöä. Kaksitasoisen aktiivisen verkkosillan vaikutuksesta DC-välipiirin keskipisteen ja kolmivaiheisen kuorman tähtipisteen välinen jännite on nollasta poikkeava aiheuttaen suurentuneen yhteismuotoisen jännitteen taajuusmuuttajan lähtöön ja verkon puolelle. Lisäksi yhteismuotoisten jännitteiden aiheuttamat kytkentätaajuiset häiriövirrat voivat aiheuttaa vikavirtasuojien tahatonta laukeamista, vaikeuttaa EMC-standardien vaatimusten täyttämistä, lisätä moottorin käämieristyksien rasitusta ja mahdollisuutta moottorin laakerivaurioille. Diplomityössä tutkitaan aktiivisen ja passiivisen verkkosillan tuottamaa yhteismuotoista jännitettä simuloinneilla. Esitellään aikaisempaa tutkimustietoa yhteismuotoisen jännitteen ja virran vaimennusratkaisuista aktiivista verkkosiltaa käytettäessä. Tutkimustiedon pohjalta suunnitellaan koelaitteistolle soveltuva suodin. Suotimen toiminta testataan simuloinnein sekä kokeellisin mittauksin. Tehdyt mittaukset osoittavat, että suunniteltu suodin vaimentaa yhteismuotoista jännitettä noin 20 dB verkkosillan kytkentätaajuudella ja tämän jälkeen yli 20 dB/dekadi taajuuteen 100 kHz asti. Lisäksi yhteismuotoisen virran suuruus syöttökaapelin kautta pieneni ehdotetun suotimen vaikutuksesta.

Pituussuunnassa hitsatun rakenneputken väsymislujuus HF –hitsausta käytettäessä

Tässä diplomityössä määritettiin pituussuunnassa hitsatun rakenneputken väsymislujuus HF –hitsausta käytettäessä. Työn tavoitteena oli vertailla eri jälkikäsittelyjen ja kahden eri materiaalin vaikutusta väsymislujuuteen. Materiaaleina kokeissa oli Ruukki double grade ja Optim 700 Plus MH. Eurokoodi 3 ja IIW määrittelee kiinnityshitseille väsymiskestävyysluokaksi 125-140, kun SN -käyrän kaltevuus, m = 3. Koetuloksia vertailtiin näihin valmiiksi määriteltyihin väsymiskestävyysluokkiin. Ruukki Metals Oy toimitti koemateriaalin kahdenlaisia väsytyskokeita varten, joiden avulla väsymislujuus voitiin määrittää. Ensimmäinen koe suoritettiin värähtelyllä hyödyntäen rakenneputken ominaistaajuutta, jolloin kuormituksen rajajännityssuhde on -1. Toinen väsytyskoe suoritettiin rakenneputkista leikatuille väsytyssauvoille, missä pituussuuntainen HF –hitsi on keskellä sauvaa. Tämä väsytyskoe suoritettiin vetotykytyksellä rajajännityssuhteella 0,1. Väsytyskokeissa havaittiin, että kiinnityshitsi täyttää sille asetetut vaatimukset, koska murtumat tapahtuivat perusaineesta. Tällöin koetuloksia vertaillaan Eurokoodi 3:n perusaineen väsymisluokkaan 160, SN -käyrän kaltevuudella m = 5. Kaikkien koetulosten väsymiskestävyysluokan keskiarvoksi saatiin 185 95 %:n todennäköisyydellä. Tutkimuksessa saatiin arvokasta tietoa kahden eri materiaalin väsymislujuudesta. Materiaalilla ei kuitenkaan havaittu vaikutusta lujuuteen. Eri jälkikäsittelyt eli juuren puolen metallipurseen höyläys tai pituussuuntaisen hitsisauman hehkutus eivät vaikuttaneet väsymislujuuteen. Kokeissa väsymismurtuma ydintyi rakenneputken pinnalta olevista alkuvioista, joten putkien käsittelyä valmistuksen jälkeen voitaisiin parantaa.

In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)

An efficient micropropagation protocol was developed for the medicinal plant Phyllanthus stipulatus (Euphorbiaceae) using nodal segments for axillary shoot proliferation. Maximum multiplication rates (8-9 shoots per explant) was achieved on MS media supplemented with either 2.5-5.0 muM IBA. The best basal media for axillary shoot proliferation when 0.62 muM BA was supplemented were MS, MS/2 and AR (4-5 shoots per explant). Rooting was achieved with 100% of the microshoots on MS medium without growth regulators. Regenerated plants were successfully acclimatized and about 88% of plantlets survived under ex vitro conditions. Flowering was observed in 81% of the ex vitro grown plantlets after 12 weeks of acclimatization. High frequency callus initiation and growth was achieved when nodal segment explants were inoculated either in the vertical position, in the light on MS medium supplemented with 5.0 muM NAA or horizontally oriented, in the dark on MS supplemented with 5.0 muM NAA or 1.25-5.0 muM BA or 2iP. Root cultures were successfully established on MS medium containing 1.1 muM NAA. The optimized micropropagation, callus and root culture protocols offer the possibility to use cell/organ culture techniques for vegetative propagation and secondary metabolism studies.

Pollination ecology of Tabebuia aurea (Manso) Benth. & Hook. and T. ochracea (Cham.) Standl. (Bignoniaceae) in Central Brazil cerrado vegetation

The pollination ecology and breeding systems of Tabebuia aurea (Manso) Benth. & Hook., and T. ochracea (Cham.) Standl. were investigated in an area of cerrado vegetation in the Federal District of Brazil. These species occur sympatrically, flower massively and synchronously for a month, during the dry season (July to September). Both have diurnal anthesis, with similar floral structures, a yellow tubular corolla and produce nectar. Fourteen species of bees visited both Tabebuia species, but, only three Centris species and Bombus morio, were considered potential pollinators, because of their high frequency on the flowers and their efficiency in carrying pollen. Tests on the breeding systems of T. aurea and T. ochracea demonstrated that boths species are self-incompatible, with late-acting self-incompatibility. The proportion of fruit set from cross pollination (T. aurea 17.2% and T. ochracea 12.3%) in both species was low considering the great number of flowers displayed. This suggests a lack of maternal resources for fruit-set. The great amount of seeds per fruit (about 92 in T. aurea and 285 in T. ochracea) may represent an investment of maternal resources allocated on higher quality of fertilized ovules.

Spatial distribution and preferential substrate of Neoregelia johannis (Carriére) L.B. Smith (Bromeliaceae) in a disturbed area of Atlantic Rainforest at Ilha Grande, RJ, Brazil

In bromeliad populations, amount of light and available substrates influence individuals spatial organization. In Atlantic Rainforest of Ilha Grande, the heliophylous bromeliad Neoregelia johannis is a large and abundant species. In this forest, it would be expected that N. johannis would occupy stable substrates, as large trunks, large branches, rock boulders or ground, with high sunlight, enough for the bromeliad survivor. In the present work, we analyzed the distribution and most used substrates of N. johannis in secondary forest. We analyzed the frequency of reproductive modes (sexual and vegetative) used by the bromeliad shoots, registering if the shoots were originated from seeds or by vegetative reproduction. The results indicated an aggregated distribution pattern (Ip = 0.052). The preferred substrate was boulders (91%), whereas tree trunks (6%) and the ground (3%) were rarely used. Small and fragile substrates are unstable to support large adults of this species, which may explain the predominant pattern of establishment over boulders within the secondary forest, as the presence of this substrate also results in more opened canopy cover. Approximately 50% of young individuals entered the population by vegetative reproduction. We conclude that the preferential habit and the aggregated distribution of N. johannis are due to the conjunction of preferred substrate with higher amount of light resulting from breaks in tree canopy over areas with rock blocks, and high frequency of recruitment by vegetative reproduction.

Pollination biology in Jacaranda copaia (Aubl.) D. Don. (Bignoniaceae) at the "Floresta Nacional do Tapajós", Central Amazon, Brazil

Jacaranda copaia (Aubl.) D. Don is a pioneer tree widespread in the Brazilian Amazon, usually found colonizing forest gaps and altered areas, and the forest fragment edges. This study investigated aspects of the floral biology, breeding system and pollinators of J. copaia trees. Flowering lasts from August to November, during the low rainfall period extending up to four weeks per tree and 3-4 months for the population as a whole, characterizing a cornucopia flowering pattern. The fruit set ends in the beginning of the rainy season, with wind dispersed winged seeds. Fruit set from open pollination was 1.06% (n = 6,932). Hand pollination using self-pollen (n = 2,099) did not set fruits. Cross-pollination resulted in 6.54% fruit set (n = 2,524), representing six times more than the natural pollination rate (1.06%, n = 6,932). Flowers excluded from insect visitation (automatic self-pollination) did not set fruits (n = 5,372). Pollen tube growth down to ovary was detected under fluorescence microcoscopy in cross-pollinated and selfed pistils. The species is an obligate allogamous plant, with late-acting self-incompatibility system. Approximately 40 species of native bees visited the flowers, but the main pollinators were medium-sized solitary bees as Euglossa and Centris species due to the compatibility between their body sizes with the corolla tube, direct contact with the reproductive structures and high frequency of visits.

Preparation of mitotic chromosomes of leaf-cutting ants from the genera Atta and Acromyrmex

Some modifications were made to the methodology of Imai et al. (Jpn. J. Genet. 63: 159-185, 1988) for cytogenetic analysis of the leaf-cutting ants Atta sexdens piriventris and Acromyrmex heyeri (Hymenoptera, Formicidae), shortening preparation time and improving chromosomal preparations. The brain ganglia of prepupae were dissected in a 0.0025% hypotonic solution of colchicine, placed on a glass slide on a cold plate (4 ± 1oC) for 20 min. The material was fixed directly on the cold slide (with cold fixative I), macerated with a histological needle and fixed again with fixative I, followed by fixatives II and III, all of them cold. The slide was flame-dried right after the use of fixative III, and it was allowed to air-dry at room temperature for 2 h. The resulting metaphases presented less contracted chromosomes, with separated and well defined sister chromatids at a high frequency, when the material was processed in the manner described and stained with 3% Giemsa in phosphate buffer (pH 6.8) for 15 min.

Distribution of HCV genotypes among different exposure categories in Brazil

Hepatitis C virus (HCV) infection is widespread and responsible for more than 60% of chronic hepatitis cases. HCV presents a genetic variability which has led to viral classification into at least 6 genotypes and a series of subtypes. These variants present characteristic geographical distribution, but their association with different responses to treatment with interferon and severity of disease still remains controversial. The aim of this study was to investigate the patterns of distribution of HCV genotypes among different exposure categories in Brazil. Two hundred and fifty anti-HCV positive samples were submitted to HCV-RNA detection by RT-PCR and their genotype was determined by restriction fragment length polymorphism (RFLP) analysis. In addition, the genotype/subtype of 60 samples was also determined by a reverse hybridization assay. HCV 1 was the most prevalent (72.0%), followed by type 3 (25.3%), HCV 2 (2.0%) and HCV 4 (0.7%). The HCV genotype distribution varied among the different exposure categories, with HCV 1 being more frequent among blood donors, hemophiliacs and hemodialysis patients. A high frequency of HCV 3 was observed in cirrhotic patients, blood donors from the South of Brazil and injecting drug users (IDUs). The general distribution of the HCV genotype in Brazil is similar to that in other regions of the world.

Atropine and ODQ antagonize tetanic fade induced by L-arginine in cats

Although it has been demonstrated that nitric oxide (NO) released from sodium nitrite induces tetanic fade in the cat neuromuscular preparations, the effect of L-arginine on tetanic fade and its origin induced by NO have not been studied in these preparations. Furthermore, atropine reduces tetanic fade induced by several cholinergic and anticholinergic drugs in these preparations, whose mechanism is suggested to be mediated by the interaction of acetylcholine with inhibitory presynaptic muscarinic receptors. The present study was conducted in cats to determine the effects of L-arginine alone or after pretreatment with atropine or 1H-[1,2,4]oxadiazole [4,3-a]quinoxalin-1-one (ODQ) on neuromuscular preparations indirectly stimulated at high frequency. Drugs were injected into the middle genicular artery. L-arginine (2 mg/kg) and S-nitroso-N-acetylpenicillamine (SNAP; 16 µg/kg) induced tetanic fade. The Nw-nitro-L-arginine (L-NOARG; 2 mg/kg) alone did not produce any effect, but reduced the tetanic fade induced by L-arginine. D-arginine (2 mg/kg) did not induce changes in tetanic fade. The tetanic fade induced by L-arginine or SNAP was reduced by previous injection of atropine (1.0 µg/kg) or ODQ (15 µg/kg). ODQ alone did not change tetanic fade. The data suggest that the NO-synthase-GC pathway participates in the L-arginine-induced tetanic fade in cat neuromuscular preparations. The tetanic fade induced by L-arginine probably depends on the action of NO at the presynaptic level. NO may stimulate guanylate cyclase increasing acetylcholine release and thereby stimulating presynaptic muscarinic receptors.

Coexistence of potentiation and fatigue in skeletal muscle

Twitch potentiation and fatigue in skeletal muscle are two conditions in which force production is affected by the stimulation history. Twitch potentiation is the increase in the twitch active force observed after a tetanic contraction or during and following low-frequency stimulation. There is evidence that the mechanism responsible for potentiation is phosphorylation of the regulatory light chains of myosin, a Ca2+-dependent process. Fatigue is the force decrease observed after a period of repeated muscle stimulation. Fatigue has also been associated with a Ca2+-related mechanism: decreased peak Ca2+ concentration in the myoplasm is observed during fatigue. This decrease is probably due to an inhibition of Ca2+ release from the sarcoplasmic reticulum. Although potentiation and fatigue have opposing effects on force production in skeletal muscle, these two presumed mechanisms can coexist. When peak myoplasmic Ca2+ concentration is depressed, but myosin light chains are relatively phosphorylated, the force response can be attenuated, not different, or enhanced, relative to previous values. In circumstances where there is interaction between potentiation and fatigue, care must be taken in interpreting the contractile responses.