Chemoimmunoprophylaxis against bovine tropical theileriosis in young calves: a comparison between buparvaquone and long-acting oxytetracycline

Eighteen seven to 21-day-old crossbred (Bos taurus cross Bos indicus) calves were allocated to four groups (A to D). Groups A and B each consisted of six calves and groups C and D three calves each. Each calf in groups A, B and C was inoculated with ground-up tick supernate (GUTS) equivalent to two infected acini prepared from Theileria annulata-infected Hyalomma anatolicum anatolicum. Each calf in group A was also given a single intramuscular injection of buparvaquone, 2.5 mg kg-1 bodyweight simultaneously with GUTS, whereas each calf in group B was given a single intramuscular injection of long-acting oxytetracycline, 20 mg kg-1 bodyweight following inoculation of GUTS. In calves of group A clinicopathological reactions were negligible, whereas in calves of group B mild to severe reactions were observed resulting in the death of three of the six calves. All the calves of group C (infected, untreated controls) died of acute theileriosis. All the surviving calves of groups A and B withstood a lethal homologous challenge given on day 30 after immunisation, indicating no difference in the immune status of the surviving calves of the two groups. Group D, challenge control, all calves died of theileriosis within 18 days of challenge.     

Immunization against bovine tropical theileriosis, using 60Co-irradiated infective particles of Theileria annulata (Dschunkowsky and Luhs 1904) derived from ticks.

Portions of ground supernate material from Theileria annulata-infected and prefed adults of the Hyalomma anatolicum anatolicum were irridiated by 60Co source at 0, 3, 5, 6, 7, or 9 krads. These portions were injected subcutaneously into different groups of cross-bred calves. The calves injected with 0-, 3-, or 5-krad irradiated tick supernate had severe reactions (rectal temperature 39.8 to 41.6 C, two- to fourfold enlargement of prescapular lymph gland, mean peak parasitemia 27.3% to 32.5% infected erythrocytes, decreased PCV 41.7% to 60.7%, and hemoglobin concentration 37.5% to 50.8%), and many died, whereas those injected with 6- or 7-krad irradiated tick supernate had minimal reactions (rectal temperature 39.2 to 39.8 C, slight enlargement of prescapular lymph gland, parasitemia less than 1%, decrease packed cell volume 15.1%, and hemoglobin concentration 20.1%), with no mortality. All surviving calves injected with nonirradiated (0-) or 3-, 5-, 6-, or 7-krad irradiated tick supernate developed comparable indirect fluorescent antibody titers and were resistant to challenge exposure with infective material from 30 ticks. The calves injected with 9-krad irradiated tick supernate showed no reactions and did not develop indirect fluorescent antibody titers; they were also susceptible to challenge exposure with infective tick material.     

Coat protein-mediated transgenic resistance in tomato against a IB subgroup Cucumber mosaic virus strain

Transgenic tomato plants containing the coat protein (CP) gene of Cucumber mosaic virus (CMV) of subgroup IB were developed through Agrobacterium-mediated transformations. The progenies of transgenic plants showed the presence of transgene, its expression and translation of 26 KDa CP. The T₁ and T₂ generation plants were evaluated for resistance against challenge inoculations by a homologous strain of CMV. Visual observations of challenged transgenic plants categorized them into resistant, tolerant and susceptible as compared with untransformed control plants. Out of 33 plants of the T₁ generation, 36.3% showed resistance and remained symptomless throughout their life, 48.4% showed tolerance which developed delayed symptoms of mild mosaic, and 15.1% showed susceptibility to CMV which developed severe systemic mosaic and leaf distortion symptoms after 30?days of virus challenge. Out of 120 plants of the T₂ generation, 60% showed resistance, 26.6% were tolerant and only 13.3% were found susceptible to challenge inoculations of CMV. Resistant transgenic plants also showed less CP accumulation in systemic upper leaves as compared with challenged untransformed plants. In this study, CP of a CMV subgroup IB strain has demonstrated a significant level of resistance in transgenic tomato plants against the CMV strain. The strategy may be applied for better quality and productivity of tomato crops.     

Prevalence of Coxiella burnetii antibodies in Portuguese dairy cattle herds

Q fever is an important zoonotic disease which has been recently diagnosed, mainly in sheep and goats, in Portugal. The aim of the present study was to determine the prevalence of bovine Coxiella burnetii antibodies in dairy farms from the northwest of Portugal. Bulk tank milk samples were randomly obtained, on November 2013, from 90 dairy farms and assayed using an ELISA kit. The apparent prevalence was 61.1 % (95 % C.I. from 50.8 to 70.5 %). The proportion of negative and intermediate (inconclusive) herds was 34.5 % (25.5 to 44.7 %) and 4.4 % (1.7 to 10.9 %), respectively. In conclusion, a high level of exposure to Coxiella burnetii was observed in Portuguese dairy cattle herds, highlighting the needs to better understand the epidemiology of Q fever in Portugal by the implementation of a monitoring program based on harmonized serologic and molecular methodologies and elucidation of the infection status of the herds.

     

Molecular characterization of Cucumber mosaic virus strain causing severe mosaic disease on petunia in India

Severe mosaic, yellowing and stunting symptoms were observed on petunia (Petunia hybrida L.) growing in pots at NBRI and in various gardens of Lucknow, India. The association of Cucumber mosaic virus (CMV) with the mosaic disease was detected based on positive bioassay on susceptible hosts, isometric cored virus particles of ~28?nm during electron microscopic observations in leaf dip preparations and positive amplification of expected size (~650?bp) during RT-PCR using coat protein gene specific primers. Further, the complete RNA 3 genomic fragment of virus isolate was amplified by RT-PCR using RNA 3 specific primers. The obtained amplicons of ~2.2 Kb were cloned and sequenced. The analysis of sequence data of RNA 3 revealed highest sequence identities (96%) with several CMV strains which belong to subgroup IB. The virus isolate also showed closest phylogenetic relationships with banana strain of CMV of subgroup IB (Acc. EF178298) reported from India. To the best of our knowledge, we report the first molecular characterization of CMV strain of subgroup IB causing severe mosaic disease on petunia in India.     

Proteomic analysis of multidrug resistant Escherichia coli strains from scouring calves

A number of researchers have used chemical inhibitors that target membrane efflux pumps as an experimental treatment strategy for multidrug resistant (MDR) bacterial infections. However, most of these compounds are toxic in vertebrate animals. The present research was therefore done to describe expression dynamics of drug resistance-associated Escherichia coli proteins that could serve as novel drug targets. Proteomes of MDR and antimicrobial susceptible (AS) E. coli were studied in two dimensional (2-D) polyacrylamide gels and liquid chromatography-mass spectrometry (LC-MS) was performed on proteins of interest. The number of recovered peptides per protein was used to elucidate the amounts of target proteins expressed in MDR and AS E. coli strains. Eight proteins that may be potentially involved in mechanisms of drug resistance were analyzed and identified by LC-MS. These were grouped into membrane porins (TolC, OmpA, OmpC, Nmpc Precursor), proteins involved in microbial protein synthesis (EF-Ts, EF-Tu, RpsA) and Dps, a protein of unknown location and function. Experimental data demonstrated variability in the expression patterns and quantities of the four porins (TolC, OmpA, OmpC, Nmpc precursor), the three microbial protein synthesis associated proteins (EF-Ts, EF-Tu and RpsA), and Dps which has been previously associated with drug resistance. While variability was seen in quantities and expression patterns of some of the proteins of interest, the present data falls short of determining the suitability of these proteins as novel drug targets. Further studies are required to explore how these proteins could be targeted for drug development.     

华北玉米秸秆覆盖对砂土、壤土水土保持效应的影响

通过野外径流场模拟降雨试验,研究玉米秸秆覆盖对砂土和壤土产流产沙过程的影响,探索不同土壤质地下水土保持的临界秸秆覆盖条件。处理分为2种土壤质地类型和5个水平的秸秆覆盖度:0、10%、20%、30%和40%。结果表明:壤土抗侵蚀能力优于砂土,但透水性弱于砂土;不同土壤质地条件下秸秆覆盖效益存在差异,相同的秸秆覆盖时,砂土条件下的土壤侵蚀防治效果优于壤土;2种土壤质地条件秸秆覆盖度30%时可显著提高土壤入渗总量(25.7%~33.9%),减少产沙总量(22.2%~46.4%),对水土流失具有良好的防治效果。考虑到过大的秸秆覆盖度(大于80%)会造成播种机堵塞,在华北保护性耕作研究实践中,建议砂土和壤土质地下的农田地表保持1 600~3 000 kg/hm2(30%~60%)的玉米秸秆覆盖,以达到较好的水土保持效果和播种质量。