Proteins in the saliva of the Ixodida (ticks): Pharmacological features and biological significance

The saliva of ticks (Suborder Ixodida) is critical to their survival as parasites. A tick bite should result in strong responses from the host defence systems (haemostatic, immune and inflammatory) but tick saliva appears to have evolved to counter these responses. We review current knowledge of tick saliva components, with emphasis on those molecules confirmed to be present in the secreted saliva but including some that have only been confirmed to be present in salivary glands. About 50 tick saliva proteins that are well described in the literature are discussed. These saliva components include enzymes, enzyme inhibitors, amine-binding proteins and cytokine homologues that act as anti-haemostatic, anti-inflammatory or immuno-modulatory agents. Sequence comparisons are illustrated. The importance of tick saliva and the significance of the findings to date are also discussed. (C) 2006 Elsevier Ltd. All rights reserved.

Sequencing a new target genome: The Boophilus microplus (Acari : Ixodidae) genome project

The southern cattle tick, Boophilus microplus (Canestrini), causes annual economic losses in the hundreds of millions of dollars to cattle producers throughout the world, and ranks as the most economically important tick from a global perspective. Control failures attributable to the development of pesticide resistance have become commonplace, and novel control technologies are needed. The availability of the genome sequence will facilitate the development of these new technologies, and we are proposing sequencing to a 4-6X draft coverage. Many existing biological resources are available to facilitate a genome sequencing project, including several inbred laboratory tick strains, a database of approximate to 45,000 expressed sequence tags compiled into a B. microplus Gene Index, a bacterial artificial chromosome (BAC) library, an established B. microplus cell line, and genomic DNA suitable for library synthesis. Collaborative projects are underway to map BACs and cDNAs to specific chromosomes and to sequence selected BAC clones. When completed, the genome sequences from the cow, B. microphis, and the B. microphis-borne pathogens Babesia bovis and Anaplasma marginale will enhance studies of host-vector-pathogen systems. Genes involved in the regeneration of amputated tick limbs and transitions through developmental stages are largely unknown. Studies of these and other interesting biological questions will be advanced by tick genome sequence data. Comparative genomics offers the prospect of new insight into many, perhaps all, aspects of the biology of ticks and the pathogens they transmit to farm animals and people. The B. microplus genome sequence will fill a major gap in comparative genomics: a sequence from the Metastriata lineage of ticks. The purpose of the article is to synergize interest in and provide rationales for sequencing the genome of B. microplus and for publicizing currently available genomic resources for this tick.

Perfil sorológico contra Rickettsia spp e Leptospira spp e infestação de carrapatos em suínos mantidos sob diferentes sistemas de criação

The various types of pig farming, intensive and extensive, expose them to pig parasites but also to those from the environment of the breeding site. In this work was evaluated the exposure of bigs bred in technified farms, SISCAL (intensive breeding system in pens) and not technified (backyard) to leptospira, ticks and rickettsiae. Blood sera were analyzed to determine titers of antibodies anti-Leptospira by SAM technique and antibodies anti-rickettsial by IFA, pigs were inspected for ticks and in their breeding environment and surrounding areas (pastures and riparian vegetation), ticks were collected by the flannel dragging technique. In the farms of pigs 10.4% had anti-Leptospira antibodies, followed by SISCAL (8%) and backyard animals (2.5%). The serovars found were Bratislava, Pomona, serovar, Canicola and Icterohaemorrhagiae. Higher percentage of properties with pigs raised outdoors (SISCAL) had tick infested animals (20%) than those raised in backyard (6.7%), while commercial farms had no infested pigs nor infested breeding place. In both SISCAL and backyard pig breeding properties ticks were observed at the breeding site environment. Tick infestations were detected in areas surrounding pig breeding site in all three husbandry suystems. Ticks found were all Amblyomma scultpum nymphs or adults with the exception of one of Amblyomma parvum adult. In relation to anti-rickettsia serology to five Rickettsia species, 55.2% of pigs from commercial farms reacted to al least one species, backyard pigs reacted to 89.7% and all pigs of SISCAL showed anti-rickettsia titers. Consecutive tick sampling (June 2014 to February 2016) in SISCAL FAZU in Uberaba, showed the establishment A. sculptum ticks maintained by domestic pigs. These observations demonstrate the ability the pigs to maintain populations of A. sculptum at a favorable environment and may indicate a new trend in environmental infestations by this species of tick. Exposure to Leptospira and Rickettsia demonstrated the potential pigs exposure and transmission of important diseases in public health.

Ethanol production from brown seaweed using non-conventional yeasts

The use of macroalgae (seaweed) as a potential source of biofuels has attracted considerable worldwide interest. Since brown algae, especially the giant kelp, grow very rapidly and contain considerable amounts of polysaccharides, coupled with low lignin content, they represent attractive candidates for bioconversion to ethanol through yeast fermentation processes. In the current study, powdered dried seaweeds (Ascophylum nodosum and Laminaria digitata) were pre-treated with dilute sulphuric acid and hydrolysed with commercially available enzymes to liberate fermentable sugars. Higher sugar concentrations were obtained from L. digitata compared with A. nodosum with glucose and rhamnose being the predominant sugars, respectively, liberated from these seaweeds. Fermentation of the resultant seaweed sugars was performed using two non-conventional yeast strains: Scheffersomyces (Pichia) stipitis and Kluyveromyces marxianus based on their abilities to utilise a wide range of sugars. Although the yields of ethanol were quite low (at around 6 g/L), macroalgal ethanol production was slightly higher using K. marxianus compared with S. stipitis. The results obtained demonstrate the feasibility of obtaining ethanol from brown algae using relatively straightforward bioprocess technology, together with non-conventional yeasts. Conversion efficiency of these non-conventional yeasts could be maximised by operating the fermentation process based on the physiological requirements of the yeasts.

Biomethane production from macroalgae

Irish brown seaweeds have been identified as a potential bio-resource with potentially high specific methane yields. Anaerobic digestion is deemed the most feasible technology due to its commercial viability for handling such wet feedstock. However, the biomethane potential of seaweed is highly dependent on its chemical composition which can vary by species type, cultivation method, and time of harvest. This study aims to investigate and optimize the process for the production of biomethane from Irish brown seaweeds focusing on the key technology bottlenecks including for seaweed characterization, biomethane potential assessment, optimization of long-term anaerobic digestion and suitable pre-treatment technologies to enhance potential gas yields. Laminaria digitata and Ascophyllum nodosum were tested for seasonal variation. From the characterization and batch digestion of L. digitata, August was found to be the optimal month for harvest due to high organic matter content, low level of ash and ultimately highest biomethane yield. The specific methane yield of 53 m3 CH4 t-1 wwt in August was 4.5 times higher than the yield in December (12 m3 CH4 t-1 wwt), with ash content the key factor in seasonal variation. For A. nodosum, the optimal harvest month was October with polyphenol content found to be a more influential factor than ash. The gross energy yields from both species were evaluated in the range of 116-200 GJ ha-1 yr-1. Continuous digestion trials were subsequently designed for S. latissima and L. digitata to optimize the key digestion parameters. Results from mono-digestion and co-digestion with dairy slurry revealed that both seaweeds could be digested at maximum biomethane efficiency to a loading rate of 4 kg VS m-3 d-1. Accumulation of salt in the digesters was a concern for long term digestion and it was reasoned that suitable pretreatment may be required prior to digestion. Various pre-treatments were subsequently tested on L. digitata to enhance the gas yield. It was found that maceration after hot water washing yielded 25% more specific methane and up to 54% salt removal as compared to untreated L. digitata. The experiments undertaken aim to assist in providing a basic guideline for feasible design and operation of seaweed digesters in Ireland.