Artificial regeneration with <Emphasis Type="BoldItalic">Quercus ilex</Emphasis> L. and <Emphasis Type="BoldItalic">Quercus suber</Emphasis> L. by direct seeding and planting in southern Spain

 Introduction   

The limited ability of Quercus species to regenerate naturally in Mediterranean forests has led to the development of various artificial regeneration methods; however, there is no general consensus as to what specific method is the best one for this purpose.     

<Emphasis Type="Italic">In vitro</Emphasis> morphogenic response of leaf sheath of <Emphasis Type="Italic">Phyllostachys bambusoides</Emphasis>

Nodal segments from secondary branches of saplings of Phyllostachys bambusoides were inoculated in MS medium to assess the in vitro morphogenic response of leaf sheath through the induction to callogenesis by Picloram(4-amino-3,5,6-trichloropicolinic acid) at different concentrations of carbohydrate under the same conditions with presence or absence of luminosity.In our experiment,secondary explants were kept in MS medium containing 8.0 mg·L-1 of Picloram for the callus formation.Calluses were transferred in MS medium supplemented with sucrose,fructose and glucose(control,2%,4% and 6%).Results show that Picloram induced the callogenesis in leaf sheath.The secondary embryogenesis was formed in yellow-globular callus.The sucrose as carbohydrate source in the absence of light was more efficient to induce rhizogenesis.Glucose was more efficiency in the presence of light.Callogenic induction and further embryogenesis evidenced the competence and determination of leaf sheath cells.     

Comparison of the development <Emphasis Type="Italic">in planta</Emphasis> of a pyrrolnitrin-resistant mutant of <Emphasis Type="Italic">Botrytis cinerea</Emphasis> and its sensitive wild-type parent isolate

Botrytis cinerea is able to build-up resistance to pyrrolnitrin, an antibiotic produced by diverse biocontrol agents, possibly compromising the durability of this method of disease control. The development of two near-isogenic lines of B. cinerea differing in their level of resistance to pyrrolnitrin was compared in tomato plants and on PDA medium. In tomato plants, significant differences in the percentage of infected petioles 1 day after inoculation and in symptom progression on petioles and stems were observed between the resistant mutant and the sensitive wild-type parent, suggesting a difference in their level of aggressiveness. Cytohistological investigations revealed that conidia of both near-isogenic lines germinated 6 h after inoculation and mycelium developed within petiole tissues 12 h after inoculation. However, while the wild-type parent isolate spread throughout the petiole and rapidly invaded the stem tissues via the leaf-abscission zone 72 h after inoculation, the pyrrolnitrin-resistant mutant failed to extend beyond petiole tissues to invade the stem. Moreover, 72 h after inoculation, the mycelial development of the pyrrolnitrin-resistant mutant was accompanied by abnormal glycogen accumulation and chlamydospore-like cell formation. In contrast, wild-type parent mycelium was normally structured with intensive colonization of stem tissues. Additionally, on PDA medium the mycelium of the pyrrolnitrin-resistant mutant was less vigorous than the wild-type isolate. These results suggest that the acquisition of pyrrolnitrin-resistance in B. cinerea is accompanied by changes in mycelial structure and reduction in mycelial growth, leading to a noticeable loss of aggressiveness on tomato plants.     

Plasma and urine concentrations of marbofloxacin following single subcutaneous administration to cats

The pharmacokinetic properties of marbofoxacin, a third generation fluoroquinolone, were investigated in 12 healthy adult cats after single subcutaneous (SC) administration of 2 mg/kg BW (Part I, n=8 cats) and 4 mg/kg BW (Part II, n=4 cats). In each part of the study blood and urine samples were collected before treatment and thereafter for 5 days. The plasma and urine concentrations of marbofloxacin were determined by HPLC with UV detection. Pharmacokinetic calculations were performed for each treated animal using an open one-compartment-model with first-order elimination after SC dosing. Marbofloxacin in plasma (means): Maximum concentrations (Cmax) of about 1.2 and 3.0 microg/ml were measured 2.3 and 4 hours (tmax) after dosing of 2 and 4 mg/kg BW, respectively. Elimination from the body was low with a total clearance (Cl/F) of approximately 0.1 l/h/kg for both dosages. The half-life (t 1/2) for this process was calculated with 8-10 hours. AUC increased almost proportional when doubling the dose, i.e., 19.77 +/- 6.25 microg * h/ml (2 mg/kg BW) and 51.26 +/- 11.83 microg * h/ml (4 mg/kg BW). Plasma kinetics measured were in accordance with data from literature. Marbofloxacin in urine (means): Maximum drug concentrations were detected 4 and 8 hours after dosing with 70 microg/ml (2 mg/kg BW) and 160 microg/ml (4 mg/kg BW), respectively. Inhibitory effects of the urinary matrix on the antimicrobial activity of the drug were taken into account when performing PK/PD calculations. However, a concentration-dependent bactericidal activity (Cmax/MIC > 8-10) which is claimed for fluoroquinolones was sufficiently met with focus on Escherichia (E.) coli (MIC90 0.5 microg/ml). In the same matrix a threshold value of 1.0 microg/ml was undercut 82 and 116 hours after SC dosing, respectively. Hence, a time-dependent bacteria killing kinetic (T > MIC) which may be of relevance for some Gram-positive germs like Staphylococcus spp. (MIC90 1.0 microg/ml) should be covered, too.     

Location of RAD51-like protein during meiotic prophase in Eimeria tenella

This study focuses on reporting events in Eimeria tenella oocysts from early to late prophase I in terms of RAD51 protein in association with the synaptonemal complex formed between homologous chromosomes. The aim of the study was the sequential localization of RAD51 protein, which is involved in the repair of double-strand breaks (DSBs) on the eimerian chromosomes as they synapse and desynapse. Structural Maintenance of Chromosome protein SMC3, which plays a role in synaptonemal complex formation, was labeled to identify initiation and progress of chromosome synapsis and desynapsis in parallel with the appearance and disappearance of RAD51 foci. Antibodies directed against RAD51 and cohesin subunit SMC3 proteins were labeled with either fluorescence or colloidal gold to visualize RAD51 protein foci and synaptonemal complexes. RAD51 protein localization during prophase I was studied on meiotic chromosomes spreads obtained from oocysts at different points in time after the start of sporulation. The present findings showed that foci detected with the antibody directed against RAD51 protein first appeared at the pre-leptotene stage before homologous chromosomes began pairing. Subsequently, the foci were detected in association with the lateral elements at the precise sites where synapsis were in progress. These findings lead us to suggest that in E. tenella, homologous chromosome pairing was a DSB-dependent mechanism and reinforced the participation of RAD51 protein in meiotic homology search, alignment and pairing of chromosomes.     

Craniomandibular osteopathy with a unique neurological manifestation in a young Akita

This report describes a 4 mo old intact male Akita that presented for evaluation of a life-long history of facial swelling and failure to thrive. Physical examination revealed an enlarged cranium with prominent bony swellings on the maxillary bone, excessive laxity and crepitus involving multiple joints, and proprioceptive deficits. Radiographs demonstrated multiple osseous abnormalities including endosteal thickening of the femurs and ilium. Necropsy revealed gross compression of the cerebellum and brainstem. Physical exam findings, radiographic abnormalities, and histopathology of multiple bony lesions were all consistent with craniomandibular osteopathy. In this unique case of craniomandibular osteopathy, the dog was affected with severe bony proliferations leading to generalized hyperostotic lesions and brainstem compression resulting in neurologic deficits.     

Colonization factors of Campylobacter jejuni in the chicken gut

ABSTRACT: Campylobacter contaminated broiler chicken meat is an important source of foodborne gastroenteritis and poses a serious health burden in industrialized countries. Broiler chickens are commonly regarded as a natural host for this zoonotic pathogen and infected birds carry a very high C. jejuni load in their gastrointestinal tract, especially the ceca. This eventually results in contaminated carcasses during processing. Current intervention methods fail to reduce the colonization of broiler chicks by C. jejuni due to an incomplete understanding on the interaction between C. jejuni and its avian host. Clearly, C. jejuni developed several survival and colonization mechanisms which are responsible for its highly adapted nature to the chicken host. But how these mechanisms interact with one another, leading to persistent, high-level cecal colonization remains largely obscure. A plethora of mutagenesis studies in the past few years resulted in the identification of several of the genes and proteins of C. jejuni involved in different aspects of the cellular response of this bacterium in the chicken gut. In this review, a thorough, up-to-date overview will be given of the survival mechanisms and colonization factors of C. jejuni identified to date. These factors may contribute to our understanding on how C. jejuni survival and colonization in chicks is mediated, as well as provide potential targets for effective subunit vaccine development.     

Predicting fadeout versus persistence of paratuberculosis in a dairy cattle herd for management and control purposes: a modelling study

ABSTRACT: Epidemiological models enable to better understand the dynamics of infectious diseases and to assess ex-ante control strategies. For Mycobacterium avium subsp. paratuberculosis (Map), possible transmission routes have been described, but Map spread in a herd and the relative importance of the routes are currently insufficiently understood to prioritize control measures. We aim to predict early after Map introduction in a dairy cattle herd whether infection is likely to fade out or persist, when no control measures are implemented, using a modelling approach. Both vertical transmission and horizontal transmission via the ingestion of colostrum, milk, or faeces present in the contaminated environment were modelled. Calf-to-calf indirect transmission was possible. Six health states were represented: susceptible, transiently infectious, latently infected, subclinically infected, clinically affected, and resistant. The model was partially validated by comparing the simulated prevalence with field data. Housing facilities and contacts between animals were specifically considered for calves and heifers. After the introduction of one infected animal in a naive herd, fadeout occurred in 66% of the runs. When Map persisted, the prevalence of infected animals increased to 88% in 25 years. The two main transmission routes were via the farm's environment and in utero transmission. Calf-to-calf transmission was minor. Fadeout versus Map persistence could be differentiated with the number of clinically affected animals, which was rarely above one when fadeout occurred. Therefore, early detection of affected animals is crucial in preventing Map persistence in dairy herds.