Rhipicephalus microplus inverkan på nötboskap

SAMMANFATTNING Rhipicephalus (Boophilus) microplus, cattle tick, är en vitt spridd fästingart som angriper bland annat nötboskap. Ofta fokuseras det på de sjukdomar som fästingen är vektor för, men syftet i den här uppsatsen är att belysa effekten av själva fästingen på boskap. Informationshämtning har skett genom en litteraturstudie. I det här arbetet har frågan om hur fästingens parasitism påverkar boskap har produktionspåverkan studerats. Flertalet studier har dragit slutsatsen att fästingangrepp har negativ inverkan på nötboskap med symtom som minskad viktuppgång och försämrad mjölkavkastning. Effekterna av fästingangreppet tycks bestå av dels en specifik effekt genom den anemi som kan uppstå då blodmål tas från värddjuret, men även en metabolisk effekt som leder till bland annat hypoalbuminemi samt anorexia. Mekanismen som ligger bakom de metaboliska störningarna är inte noga studerad, men föreslås kunna orsakas av ett toxin producerat av fästingen. En förvärvad immunitet mot R. microplus återfinns hos vissa boskap, och tros vara bättre hos Bos indicus jämfört med Bos taurus. Frågan varför en förvärvad immunitet skiljer sig mellan raser behandlas i uppsatsen, med fokus på om det finns någon skillnad och i så fall vad den utgörs av. Det verkar som att B. indicus har en bättre förmåga att motstå fästingangrepp, och det genom att förhindra att fästingen lyckas bita sig fast i huden. Den immunologiska orsaken till detta är ännu oklar. Hos B. taurus har cellmedierade hypersensitivitetsreaktioner observerats i samband med fästingbett, en reaktion som inte har hittats hos B. indicus. Den förvärvade immuniten verkar vara genetiskt kopplad och ärftlig, men påverkas även av faktorer som klimat och djurets pälstyp. Som bakgrund behandlas kort nötboskapens ursprung i den här uppsatsen, och enligt den troligaste teorin har B. taurus och B. indicus skilda ursprung, med början i två olika arter av uroxe. I enlighet med det har B. indicus och R. microplus ursprung ur samma område, södra Asien, till skillnad från B. taurus. Det är möjligt att en samevolution har skett, vilket har gett B. indicus bättre försvar mot angrepp av R. microplus.SUMMARY Rhipicephalus (boophilus) microplus, also called cattle tick, is widely spread across the world. Studies involving the tick often focus on the ticks capacity as a disease carrier. In this paper the effect on cattle by the tick it self is examined. Focus is mainly on two different aspects, the effect on cattle production and the resistance of the host. Many studies agree on the conclusion that the tick has a negative influence on cattle production. Results like reduced weight gain and a reduction in milk yield is observed. There seems to be two different aspects of at tick bite that is affecting the host. One direct effect resulting in anemia from the blood loss caused by the blood consuming tick, but also a metabolic effect resulting in hypoalbuminemia and anorexia. The reason to why the animals is showing signs of metabolic disturbances is however unclear, with only suggestions of a toxin originating from the tick. To the aspect of immunity, some cattle has the ability to resist the tick bites. There seems to be a difference between cattle dependent of their breed and species. In several studies, Bos indicus is suggested to have a better resistance than Bos taurus, demonstrade by a capability to prevent the tick from biting. The reason to this is not completeley investigated, but the immunological response to the tick bite differs between B. taurus and B. indicus. B. taurus shows a cell mediated hyper sensitivity reaction, a reaction that hasn’t been found in B. indicus. The cattles immuntiy seems to be genetically linked and is hereditary but is also influenced by the weather and the animals type of fur. As a background, the evolution of cattle is shortly mentioned. A diverged origin with beginning i two different types of aurochs, with a possible coevolution of B. indicus and their aurochs ancestor Bos primigenicus namandicus togheter with R. microplus. This can maybe explain why B. indicus is better protected from the tick

Forest structure and economy over 100 years with fixed or varied buffer zone around watercourses

Skogsbruksåtgärder intill vatten kan ge negativa konsekvenser på vattenkvalitén. Ett sätt att minska den negativa påverkan är att skapa skyddszoner. I denna studie simulerades olika skyddszoner i Heureka PlanVis och utvärderades med avseende på ekologiska, ekonomiska och sociala värden sett över längre tid. Tre nivåer av skyddszoner med varierad bredd baserade på djupet till grundvattnet (DTW-index) samt två fasta skyddszoner på 15 och 0 m jämfördes. I DTW-skyddszonerna avsattes mark med ≤ 1, ≤ 0,5 respektive ≤ 0,25 m ner till grundvattnet. I skyddszon DTW ≤ 1 m uppmättes nedanstående variablers extremvärden. Värdena redovisas nedan i jämförselse med om ingen skyddszon användes: • Avsatt areal var 9 % av undersökningsområdets totalareal. • Kostnaden för att lämna skyddszon var 10,5 % i minskat nuvärde. • Medelvolymen lövträd över 100 år ökade med 6,2 %. • Medelvolymen skog > 120 år över 100 år ökade med totalt 9155 m3sk. • Medelvolymen död ved/ha över 100 år ökade med 28,9 %. • Medelvärdet i rekreationsindex över 100 år minskade med 6,2 %. • Arealen inom skyddszon opåverkad av kanteffekter var 0,19 % av undersökningsområdets totalareal, vid en förväntad kanteffektslängd på 50 m. • Arealen inom skyddszon opåverkad av kanteffekter var 3 % av undersökningsområdets totalareal, vid en förväntad kanteffektslängd på 15 m. Studien indikerar att nämnda variabler avgörs av skyddszonens utformning. Eftersom skyddszoner utformade med DTW-index är topografiskt och hydrologiskt betingade kan de bidra till att utströmningsområden skyddas samtidigt som skogsbruk tillåts på mark relativt nära vatten där bärigheten är god. Detta är tilltalande för både ekonomiska och ekologiska värden.Forestry measures in proximity to water can have adverse impacts on water quality. One way to reduce the negative impact is the creation of buffer zones. In this study different buffer zones were simulated in Heureka PlanWise and evaluated for ecological, economic and social values over a longer period of time. Three levels of buffer zones of varying width based on depth to groundwater (DTW-index) and two fixed buffer zones of 15 and 0 m were compared. In the DTW-buffer zones land with ≤ 1, ≤ 0.5 and ≤ 0.25 m down to the groundwater was set aside. In buffer zone DTW ≤ 1 m the following variables extreme values was measured. The values are reported below in comparison with if no buffer zone was used: • Set aside area was 9 % of the study area's total acreage. • The cost of leaving the buffer zone was 10.5 % in diminished NPV. • The average volume of deciduous trees over 100 years increased by 6.2 %. • The average volume of forest > 120 years for over 100 years increased by a total of 9155 m3sk. • The average volume of dead wood/ha over 100 years increased by 28.9 %. • The average value of the recreation index over 100 years decreased by 6.2 %. • The area within the buffer zone unaffected by edge effects was 0.19 % of the study area's total acreage, at an expected edge effect length of 50 m. • The area within the buffer zone unaffected by edge effects was 3 % of the study area's total acreage, at an expected edge effect length of 15 m. The study indicates that these variables are determined by the buffer zone configuration. Because buffer zones designed with DTW-index is topographically and hydrologically related, they can help to protect discharge areas, while forestry is allowed on land relatively close to water where buoyancy is good. This is appealing to both economic and ecological values

Optimum N-rate and effect of split N fertilization timing on yield and quality in spring oat varieties

Split nitrogen (N) application to oats delays final decisionson total application rate, which could help achieve the economic optimum fertilization rate (OptN) and reduce nitrogen losses. Later topdressing allows adjustment of fertilizer level at a stage when it is easier to predict nitrogen supply from soil. The objectives were: to investigate whether topdressing can be applied after stem elongation and to assess effects on yield and quality in different oat varieties; and to study the variation in optimum N-rate and the possibility to predict and readjust it during the growing season. In 14 field experiments conducted in Sweden 2020–2022, the effect of split nitrogen application, with topdressing at growth stage (GS) 32, GS45, or GS55–61, on yield and quality in six different oat varieties was evaluated. Late topdressing increased grain protein concentration and decreased fat content, but variety was more important for target quality. Compared with a single early application, late topdressing did not affect yield significantly. Year and site influenced yield and quality, similarly for all varieties, but had an impact on the effect N-treatment had on protein. A multiple regression analysis showed that yield at OptN and N-uptake in unfertilized plots at GS31–47, can explain the variation in OptN and thus be used to estimate OptN. Topdressing as late as at GS45–61 increased the chances both of higher protein and more accurate prediction of OptN. Therefore, recommendations for late topdressing can be preferable if there is a target for high protein or if there are incentives to use crop sensors for late and accurate adjustments of N fertilization rates between and within fields. The recommendations should not be dependent on variety

Agroforestry boosts soil-mediated ecosystem services in the humid and sub-humid tropics: a meta-analysis

Agroforestry has been increasingly recognized as a key example of agroecological praxis contributing to the sustainable intensification of food production while providing a number of additional benefits to society. However, a quantitative synthesis of the impact of agroforestry on soil health and associated ecosystem services in the humid and sub-humid tropics is still lacking. The objective of this study was to quantify the contribution of agroforestry practices to soil-mediated ecosystem services, specifically, regulation of soil erosion, storage of soil organic carbon (SOC) and nitrogen (N), availability of soil N and phosphorus (P) to crops, and alleviation of soil acidity across the humid and sub-humid tropics. The analysis demonstrated that agroforestry can reduce soil erosion rates by 50 % compared to crop monocultures. This finding is supported by higher infiltration rates, lower runoff, higher proportion of soil macroggregates, and greater stability of soil structure under agroforestry. SOC increased by 21 %, N storage increased by 13 %, available N by 46 % and available P by 11 % while soil pH increased by 2% under agroforestry compared to crop monocultures. We conclude that agroforestry can make significant contributions to provision of soil-mediated ecosystem services in the humid and sub-humid tropics

Effects of riparian plant diversity loss on aquatic microbial decomposers become more pronounced at longer times

We examined the potential long-term impacts of riparian plant diversity loss on diversity and activity of aquatic microbial decomposers. Microbial assemblages were obtained in a mixed-forest stream by immersion of mesh bags contain-ing three leaf species (alder, oak and eucalyptus), commonly found in riparian corridors of Iberian streams. Simulation of species loss was done in microcosms by including a set of all leaf species, retrieved from the stream, and non-colonized leaves of three, two or one leaf species. Leaves were renewed every month throughout six months, and microbial inoculum was ensured by a set of colonized leaves from the previous month. Microbial diversity, leaf mass loss and fungal biomass were assessed at the second and sixth months after plant species loss. Molecular diversity of fungi and bacteria, as the total number of operational taxonomic units per leaf diversity treatment, decreased with leaf diversity loss. Fungal biomass tended to decrease linearly with leaf species loss on oak and eucalyptus, suggesting more pronounced effects of leaf diver-sity on lower quality leaves. Decomposition of alder and eucalyptus leaves was affected by leaf species identity, mainly after longer times following diversity loss. Leaf decomposi-tion of alder decreased when mixed with eucalyptus, while decomposition of eucalyptus decreased in mixtures with oak. Results suggest that the effects of leaf diversity on microbial decomposers depended on leaf species number and also on which species were lost from the system, especially after longer times. This may have implications for the management of riparian forests to maintain stream ecosystem functioning.FEDER-POFC-COMPETE and the Portuguese Foundation for Science and Technology supported this study (PEst-C/ BIA/UI4050/2011, PTDC/AAC-AMB/113746/2009 and PTDC/AAC-AMB/117068/2010), S. Duarte (SFRH/BPD/47574/2008) and I. Fernandes (SFRH/BD/42215/2007)

Experimental infection in calves with a specific subtype of verocytotoxin-producing Escherichia coli O157:H7 of bovine origin

<p>Abstract</p> <p>Background</p> <p>In Sweden, a particular subtype of verocytotoxin-producing <it>Escherichia coli </it>(VTEC) O157:H7, originally defined as being of phage type 4, and carrying two <it>vtx</it>₂genes, has been found to cause the majority of reported human infections during the past 15 years, including both sporadic cases and outbreaks. One plausible explanation for this could be that this particular subtype is better adapted to colonise cattle, and thereby may be excreted in greater concentrations and for longer periods than other VTEC O157:H7 subtypes.</p> <p>Methods</p> <p>In an experimental study, 4 calves were inoculated with 10⁹colony forming units (cfu) of strain CCUG 53931, representative of the subtype VTEC O157:H7 (PT4;<it>vtx</it>₂;<it>vtx</it>_2c). Two un-inoculated calves were co-housed with the inoculated calves. Initially, the VTEC O157:H7 strain had been isolated from a dairy herd with naturally occurring infection and the farm had previously also been linked to human infection with the same strain. Faecal samples were collected over up to a 2-month period and analysed for VTEC O157 by immuno-magnetic separation (IMS), and IMS positive samples were further analysed by direct plating to elucidate the shedding pattern. Samples were also collected from the pharynx.</p> <p>Results</p> <p>All inoculated calves proved culture-positive in faeces within 24 hours after inoculation and the un-inoculated calves similarly on days 1 and 3 post-inoculation. One calf was persistently culture-positive for 43 days; in the remainder, the VTEC O157:H7 count in faeces decreased over the first 2 weeks. All pharyngeal samples were culture-negative for VTEC O157:H7.</p> <p>Conclusion</p> <p>This study contributes with information concerning the dynamics of a specific subtype of VTEC O157:H7 colonisation in dairy calves. This subtype, VTEC O157:H7 (PT4;<it>vtx</it>_2;<it>vtx</it>_2c), is frequently isolated from Swedish cattle and has also been found to cause the majority of reported human infections in Sweden during the past 15 years. In most calves, inoculated with a representative strain of this specific subtype, the numbers of shed bacteria declined over the first two weeks. One calf could possibly be classified as a high-shedder, excreting high levels of the bacterium for a prolonged period.</p

Recurrent gross mutations of the PTEN tumor suppressor gene in breast cancers with deficient DSB repair

Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis. Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent oncogenic consequence of BRCA1-dependent dysfunction in DNA repair and provide insight into the pathogenesis of BBC with therapeutic implications. These findings also argue that obtaining an accurate census of genes mutated in cancer will require a systematic examination for gross gene rearrangements, particularly in tumors with deficient DSB repair

CD44 isoforms are heterogeneously expressed in breast cancer and correlate with tumor subtypes and cancer stem cell markers

<p>Abstract</p> <p>Background</p> <p>The CD44 cell adhesion molecule is aberrantly expressed in many breast tumors and has been implicated in the metastatic process as well as in the putative cancer stem cell (CSC) compartment. We aimed to investigate potential associations between alternatively spliced isoforms of CD44 and CSCs as well as to various breast cancer biomarkers and molecular subtypes.</p> <p>Methods</p> <p>We used q-RT-PCR and exon-exon spanning assays to analyze the expression of four alternatively spliced CD44 isoforms as well as the total expression of CD44 in 187 breast tumors and 13 cell lines. ALDH1 protein expression was determined by IHC on TMA.</p> <p>Results</p> <p>Breast cancer cell lines showed a heterogeneous expression pattern of the CD44 isoforms, which shifted considerably when cells were grown as mammospheres. Tumors characterized as positive for the CD44⁺/CD24<it>^-</it>phenotype by immunohistochemistry were associated to all isoforms except the CD44 standard (CD44S) isoform, which lacks all variant exons. Conversely, tumors with strong expression of the CSC marker ALDH1 had elevated expression of CD44S. A high expression of the CD44v2-v10 isoform, which retain all variant exons, was correlated to positive steroid receptor status, low proliferation and luminal A subtype. The CD44v3-v10 isoform showed similar correlations, while high expression of CD44v8-v10 was correlated to positive EGFR, negative/low HER2 status and basal-like subtype. High expression of CD44S was associated with strong HER2 staining and also a subgroup of basal-like tumors. Unsupervised hierarchical cluster analysis of CD44 isoform expression data divided tumors into four main clusters, which showed significant correlations to molecular subtypes and differences in 10-year overall survival.</p> <p>Conclusions</p> <p>We demonstrate that individual CD44 isoforms can be associated to different breast cancer subtypes and clinical markers such as HER2, ER and PgR, which suggests involvement of CD44 splice variants in specific oncogenic signaling pathways. Efforts to link CD44 to CSCs and tumor progression should consider the expression of various CD44 isoforms.</p