Effect of Antibiotic-containing Extenders on Taylorella equigenitalis Contaminated Semen

Taylorella equigenitalis is a gram-negative coccobacillus and the causative agent of a transmissible venereal disease in horses known as contagious equine metritis. Outbreaks of contagious equine metritis have been documented in various countries since 1977, with the most recent discovery in the United States in December 2008. During disease occurrences, culturing semen samples for T equigenitalis before breeding may help to prevent transmission of this disease; however, little is known about the antimicrobial activity of equine semen extenders against the organism. The purpose of this study was to investigate the infectivity levels of T equigenitalis in three equine semen extenders inoculated with known concentrations of the organism. The semen extenders used for this study included INRA 96, E-Z Mixin BF, and VMDZ. In addition, Timentin was added to INRA 96 at three different concentrations (0.5, 1.0, and 1.5 mg/mL) to investigate possible synergistic effects of antibiotic supplementation of extenders. Results were based on the visual counting of the colonies on chocolate Eugon agar plates. Both INRA 96 (with added Timentin) and VMDZ (as supplied by the manufacturer) significantly reduced the numbers of T equigenitalis isolated from semen extenders as compared with INRA 96 (as supplied by the manufacturer) or the antibiotic free E-Z Mixin BF. Our findings indicate that INRA 96 (with added Timentin) or VMDZ may significantly decrease the growth of T equigenitalis in extended semen; however, it is also important to consider the possible effects of antibiotic supplemented extenders on sperm longevity and fertility in addition to eliminating specific pathogens in semen.     

Effect of Diaporthe RNA virus 1 (DRV1) on growth and pathogenicity of different <Emphasis Type="Italic">Diaporthe</Emphasis> species

A 4.1 kbp positive-strand RNA virus known as Diaporthe RNA virus 1 (DRV1) occurs in hypovirulent, non-sporulating isolates of the fungal pathogen Diaporthe perjuncta. A full-length cDNA clone of DRV1 was developed and RNA transcribed from the cDNA clone used to transfect different Diaporthe spp. The transfected species included three D. ambigua isolates and an unidentified Phomopsis asexual state of a Diaporthe sp. Successful transfections were confirmed using RT-PCR. Although the in vitro-transcribed positive sense single-stranded RNA used for transfection included vector sequences at both ends, the genomes of progeny virus from DRV1-transfected isolates were free of the vector sequences. Transfection resulted in morphological changes in these fungal pathogens. However, the presence of DRV1 did not reduce growth rate in two of the three D. ambigua or the Phomopsis sp. significantly. Pathogenicity studies showed that the transfected isolates have reduced aggresiveness.     

抗重金属植物根际细菌的植物促生长特征以及它们对黑芥种子萌发的影响

Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria(PGPR) for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting(PGP) traits, including production of siderophores and indol-3-acetic acid(IAA). Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizobacteria were also resistant to high levels of heavy metals(including As as a metalloid)(up to 480 mmol L(-1)As(V), 24 mmol L(-1)Pb(Ⅱ), 21 mmol L(-1)Cu(Ⅱ), and 4.5 mmol L(-1)Zn(Ⅱ)). Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further bioassay.The inoculation of Brassica nigra seeds with Microbacterium sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1,and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L(-1)Zn(Ⅱ). The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals.     

Clonality and phenotyping of canine lymphomas before chemotherapy and during remission using polymerase chain reaction (PCR) on lymph node cytologic smears and peripheral blood

Polymerase chain reaction (PCR) assays for the immunoglobulin and T-cell receptor genes were utilized to determine phenotype and clonality from lymph node cytologic smears and peripheral blood lymphocytes from 10 dogs with lymphoma, before chemotherapy and during remission. Results were compared with those from 13 dogs with a cytologic diagnosis of lymph node hyperplasia. Clonality was identified in 7 of the lymphomas on the basis of either lymph node cytology or peripheral blood lymphocytes before treatment. No lymph node hyperplasia samples were clonal. In 6 of the dogs with lymphoma, clonality was demonstrated during clinical remission. Detection of PCR clonality during clinical remission is an effective means of identifying minimal residual disease in canine lymphoma and thus additional work is warranted to determine if molecular remission is prognostic or predictive for outcome in well-controlled and well-defined lymphoma subtypes.     

Trait dissection of maize kernel weight: Towards integrating hierarchical scales using a plant growth approach

Maize (Zea mays L.) yield is a function of the number harvested kernels per unit land area and the individual kernel weight (KW). Kernel weight and its development show a wide variability due to the genotype, the environment, the crop management, and all possible interactions. Commercial maize hybrids differ markedly in the patterns (rate and duration of kernel growth) behind differences in final KW. The same can be observed when public or elite proprietary maize inbred lines are analyzed. To progress in our understanding of KW variability, we reviewed and discussed current knowledge for analyzing kernel growth as an integrated system, modulated by processes linking different levels of organization (the different kernel tissues, the whole kernel, the plant, the canopy). Ideas on how to integrate this knowledge towards the development of a multi-hierarchical scale framework for predicting KW under different growth environments are currently needed, as they have high relevance for dissecting the genetic basis of kernel growth and maize yield definition at the canopy level.     

Population structure of <Emphasis Type="Italic">Cylindrocladium parasiticum</Emphasis> infecting peanuts (<Emphasis Type="Italic">Arachis hypogaea</Emphasis>) in Georgia,USA

Cylindrocladium parasiticum is an important pathogen of peanut (Arachis hypogaea) causing the disease Cylindrocladium black rot. The genetic structure of this haploid pathogen was determined for populations associated with peanut in Georgia, USA. Ten polymorphic microsatellite markers were used to determine genetic and genotypic diversity among three sub-populations representing the geographic distribution of peanut production in Georgia. Among 200 isolates collected, only 10 unique multilocus haplotypes were identified, with one multilocus haplotype occurring 176 times. Although no evidence for random mating was observed, the existence of loops in a constructed haplotype network hint at the possibility of recombination events. The absence of random mating might therefore be attributed to the homothallic nature of C. parasiticum as well as the clonality of the population, without excluding the possible occurrence of recombination. Cylindrocladium parasiticum thus appears to consist of a genetically homogeneous population throughout Georgia with mainly clonal reproduction or inbreeding contributing to the observed population genetic structure.     

Germination and seedling growth of <Emphasis Type="Italic">Dimorphandra jorgei</Emphasis> MF Silva and <Emphasis Type="Italic">Swartzia macrostachya</Emphasis> Benth. var. <Emphasis Type="Italic">riedelii</Emphasis> Cowan

Dimorphandra jorgei MF Silva (Caesalpinaceae) and Swartzia macrostachya Benth. var. riedelii Cowan (Fabaceae) are tree species from the southern Bahian Atlantic Forest, identified for the restoration of degraded areas. The objective of this research is to study their seed germination and seedling growth to develop simple methods for seedling production in small scale nurseries. Because the species have distinct dormancy and germination characteristics, the seeds were submitted to different treatments. D. jorgei seeds were immersed in hot water, scarified and stored for 12 weeks in the laboratory environment (25°C). S. macrostachya seeds were submitted to different combinations of drying and storage in the laboratory environment or refrigerator (4°C). Seedlings were submitted to two light treatments for 3 months: partial shade (52% of full sun) and full shade (12% of full sun). In D. jorgei, the highest germination occurred for scarified seeds (87%) and for seeds stored for 12 weeks and then scarified (69%). In S. macrostachya the undried control seeds had the highest germination, followed by that of the refrigeration storage treatment, without predrying (99% and 97%, respectively). The average values for the growth parameters were greater in full shade for D. jorgei, while S. macrostachya seedlings showed greater growth rates in partial shade. Two months growth is recommended before D. jorgei seedlings are of the sufficient size and leaf number for field planting. On the other hand, a period of 4 months is recommended for S. macrostachya, due to its relatively slow growth.     

Acute Reactions in Dogs Treated with Doxorubicin: Increased Frequency with the Use of a Generic Formulation

During a 4-month period, 34 dogs with tumors received a total of 60 doses of a single generic formulation of doxorubicin; 13 acute drug reactions were observed in these 34 dogs, and no acute reactions were observed after replacing the product with the proprietary brand. These reactions were characterized by one or more of the following signs: pruritus; head-shaking; urticaria; erythema of the pinnal, axillary, or inguinal regions; vocalization; vomiting; hyperemic or pale mucous membranes; high heart rate; and high respiratory rate. We propose that a component unique to generic doxorubicin was responsible for the unusually high number of acute drug reactions observed.     

Genetic analysis of flowering and maturity time in high latitude spring wheat

Due to the short growing season in the high northern latitudes, the development of early maturing spring wheat (Triticum aestivum L.) cultivars is important to avoid frost damage which can lower production and quality. We investigated earliness of flowering and maturity, and some associated agronomic traits, using a set of randomly selected high northern latitude adapted spring wheat cultivars (differing in maturity) and their F₁ and F₂ crosses made in a one-way diallel mating design. The parents, and their F₁ and F₂ crosses were evaluated under field conditions over 2 years. Anthesis and maturity times were controlled by both vernalization response and earliness per se genes, mainly acting additively. Non-additive genetic effects were more important in controlling grain fill duration, grain yield and plant height. Additive × additive epistatic effects were detected for all traits studied except time to anthesis. Segregation analyses of the F₂ populations for time to anthesis indicated the presence of different vernalization response genes. Molecular genetic analyses revealed the presence of Vrn-A1 and Vrn-B1 genes in the parental cultivars. Narrow-sense heritability was medium to high (60–86%) for anthesis and maturity times but low to medium (13–55%) for grain fill duration, plant height and grain yield. Selection for early flowering/maturity in early segregating generations would be expected to result in genetic improvement towards earliness in high latitude spring wheats. Incorporation of the vernalization responsive gene Vrn-B1 in combination with vernalization non-responsive gene Vrn-A1 into spring wheats would aid in the development of early maturing cultivars with high grain yield potential for the high latitude wheat growing regions of the northern hemisphere.