木质包装中黄斑星天牛微波处理初探

为了探索微波处理作为木质包装替代处理方法的可能性,对不同规格和含水量的杨树木块进行微波处理试验,结果表明:频率为2450MHz的微波能够穿透厚度为10cm的杨树木材;当微波功率为900W时,规格为10cm×10cm×10cm和10cm×10cm×2.5cm的新木块中黄斑星天牛(Anoplophora nobolis)幼虫完全死亡所需时间分别为5min和2min;而干木块中则仅需3min和30s.对微波处理引起木材温度变化和水分损失以及天牛幼虫的水分损失进行了初步研究.     

Prevalence and risk factors associated with bovine brucellosis in herds under extensive production system in southwestern Nigeria

Using a cross-sectional survey, we determined the prevalence and risk factors associated with bovine brucellosis in herds under extensive production system in southwestern Nigeria. Antibodies to Brucella species in serum samples were tested using the Rose Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (cELISA); for milk, the milk ring test (MRT) and indirect-ELISA (i-ELISA) were used. Questionnaire was administered to cattle herdsmen to determine factors predisposing the animals to bovine brucellosis. Data were analyzed using STATA 12. From 513 serum and 635 milk samples tested among 120 herds, overall animal-level prevalence of 10.1% (95% CI 7.5–12.7%) and 20.2% (95% CI 17.1–23.3%) were recorded by RBT and MRT, respectively; while 9.4% (95% CI 6.9–11.9%) and 17.8% (95% CI 14.8–20.8%) were obtained using cELISA and i-ELISA, respectively. In all, from the 120 herds tested, 29.2% and 43.3% were positive by RBT and MRT, respectively. Multivariable logistic regression revealed that herd location (OR?=?8.12, 95% CI 1.68–38.90) and improper disposal of placenta/fetus (OR?=?17.33, 95% CI 4.81–62.33) were predictors for a seropositive herd using RBT; while herd location (OR?=?5.13, 95% CI 1.27–20.28), large herd size (OR?=?2.62, 95% CI 1.15–5.85), and occurrence of abortion for a year or more (OR?=?4.62, 95% CI 1.53–13.71) were predictors of seropositivity to antibodies to Brucella spp. using MRT. We found high prevalence of brucellosis in cattle herds under extensive management system in southwestern Nigeria. Urgent and coordinated control strategies are required to mitigate this problem.

     

Pharmacokinetics of fenvalerate after intravenous administration to sheep

The pharmacokinetics of total radioactivity and of intact fenvalerate were determined in sheep treated intravenously with radiolabelled or non-radiolabelled fenvalerate. Mean residence times (MRT) of total radioactivity and intact fenvalerate in plasma were 910 (±75) and 39 (±3) min, while harmonic mean elimination-phase half-lives (TM_β) were 990 and 82 min, each respectively. Systemic clearance values (Cl_S) of total radioactivity and intact fenvalerate were 2·8 (±0·3) ml min⁻¹ kg⁻¹ and 51·3 (±5·9) ml min⁻¹ kg⁻¹, respectively. Volumes of distribution at steady state (V_SS) were each near 2500 ml kg⁻¹. Elimination of radioactivity occurred, in part (33·3 (±3·3)% of dose), by renal excretion, at a rate (0·9 (±0·1) ml min⁻¹ kg⁻¹), similar to that of glomerular filtration. These data are consistent with a disposition model according to which intact fenvalerate was rapidly distributed into a peripheral compartment, where metabolism occurred. In addition, since the elimination half-life of fenvalerate from plasma was less than 90 min after intravenous injection, ‘flip-flop’ kinetics should be considered when longer elimination half-lives are observed after oral or dermal exposures.     

Properties and functions of proton pumps in higher plants

The properties of the major H⁺-pumps in higher plant cells are described: these are the H⁺-ATPase of the plasma membrane and the H⁺-ATPase and the H⁺-pyrophosphatase of the tonoplast. They are distinguished by their structure, mechanism of action, kinetic properties, and location within the cell. The uses and value of isolated and purified membrane vesicles in transport studies are discussed. A particular example is given by the use of plasma membrane vesicles, purified by phase partition, to study proton/ sucrose co-transport in Ricinus cotyledons. Current evidence for the interference with these pumps by growth regulators, toxins and xenobiotics is outlined.     

In vitro antimicrobial inhibition profiles of Mycoplasma bovis isolates recovered from various regions of the United States from 2002 to 2003.

Antimicrobial therapy continues to be important in reducing losses due to pneumonic forms of Mycoplasma bovis disease in beef and dairy calves. Although M. bovis diseases have been documented as frequent and economically important in the United States, there are no published reports on the antimicrobial activity of approved compounds against US strains. In this study, the authors report on the activity of 9 different antimicrobials against 223 recently recovered isolates of M. bovis. These isolates represent accessions from 5 geographic regions of the United States and were grouped by 4 tissues of origin (milk, respiratory, joint, or ear and eye). A broth microdilution test was used to determine minimum inhibitory concentration (MIC) values by reading redox changes detected in broth with alamarBlue (resazurin) indicator. For each antimicrobial, the median, MIC50, MIC90, mode, and range were calculated, and the values used for comparisons. In the absence of accepted breakpoint values, published MIC cutoff values for animal mycoplasmas as well as Clinical Laboratory Standards Institute interpretive criteria were used as a reference to define in vitro activity. The MIC values from active antimicrobials were found to distribute independently of region of origin of the isolates or of tissue of origin. Enrofloxacin, florfenicol, and spectinomycin were found to be active compounds in vitro. Oxytetracycline and chlortetracycline were active against more than half of the isolates. Very few isolates were inhibited by tilmicosin and none by erythromycin, ampicillin, or ceftiofur. The antimicrobial profiles determined for these US strains were remarkably similar to those reported for European isolates. However, unlike in Europe, there appears to be no diversity of profiles when US isolates are grouped by region or tissue of origin.     

Biocontrol of soil-borne plant pathogens: Concepts and their application

A few soil-borne plant pathogens have been controlled successfully by commercial formulations of biocontrol agents, but many attempts to develop biocontrol inoculants, although promising under experimental conditions, have met with difficulties in practice. The reasons for this are discussed in this review, which outlines some of the major findings on the behaviour of microbial inoculants in soil. It is emphasized that biocontrol also occurs naturally in current agricultural practice and can be exploited purposely, but it is vulnerable to disruption by agrochemicals or mismanagement. The future of biocontrol of soilborne plant pathogens probably lies in integrated (biorational) control systems that combine the use of commercial inoculants, where appropriate, with management practices that maintain and enhance the natural biocontrol systems.     

Immunomodulation by virulence proteins of the parapoxvirus orf virus

Three orf virus putative virulence proteins are described that exhibit immunomodulatory functions. The OVIFNR gene at the left terminus of the viral genome encodes an interferon resistance protein with homology to the E3L gene of vaccinia virus. OVIFNR functions by preventing a dsRNA-dependent kinase from inhibiting virus and cell protein synthesis as part of the interferon-induced anti-viral state within infected cells. The orf virus orthologue of the ovine interleukin-10 (vIL-10) gene is located at the right terminus of the viral genome. Both vIL-10 and host (ovine) IL-10 function in vitro as inhibitors of pro-inflammatory cytokine production by keratinocytes and macrophages, and both inhibit IFN-gamma production from activated peripheral blood lymphocytes. Both the orf virus vIL-10 and ovine IL-10 stimulate mast cell and thymocyte proliferation. In this respect the orf virus IL-10 differs from Epstein Barr virus IL-10 which does not exhibit cell proliferative activity. Finally, the orf virus GM-CSF inhibitory factor gene (GIF) at the right terminus of the viral genome encodes an inhibitor of GM-CSF that also binds IL-2. Together, these viral proteins are capable of inhibiting key components of the ovine anti-virus immune and inflammatory response.     

Effects of dietary particulate limestone, vitamin K3 and fluoride and photostimulation on skeletal morphology and osteoporosis in laying hens

1. Female chicks of a White Leghorn strain were fed three different diets from one day old: control, additional vitamin K3 (10 mg/kg), and a diet containing a combination of additional vitamin K3, sodium fluoride (10 mg/kg) and limestone in particulate rather than powdered form. At 16 weeks photoperiod was increased for half the birds from 8:16 L:D to 16:8 L:D immediately or by one hour per week to the same ultimate photoperiod for the other half. 2. Age at first egg was lower by 4.0 d for birds on the fast lighting regime but there were no overall effects of lighting on bone quality at either 25 or 70 weeks. 3. Additional vitamin K3 resulted in higher proximal tarsometatarsus cancellous bone volumes at 15 weeks and throughout the laying period compared with controls. Plasma osteocalcin concentrations were unaffected by vitamin K3 supplementation during growth. 4. The combination diet resulted in beneficial responses of 12 to 20% in most bone characteristics in hens at 70 weeks. The magnitude of these effects was similar to a previous study involving a particulate calcium source alone (Fleming et al., Poultry Science, 39: 434-440, 1998b). We conclude that the beneficial effects of the combined treatment over the lifetime of the hens were attributable mainly to the presence in the diet of a calcium source in particulate form.     

Fluorouracil as a treatment for corneal papilloma in a Malayan tapir

A 26-year-old, wild caught, male Malayan tapir at the Miami Metrozoo with bilateral corneal papillomas was serially immobilized and given subconjunctival injections of fluorouracil. Over the course of 17 weeks five bilateral injections of 25 mg fluorouracil were given. This treatment caused regression of the corneal lesions as evidenced by decreased lesion diameter, decreased corneal vascularity, increased corneal clarity, and improved visual function. No adverse drug effects were observed.