Home About us Contact
|
Home About us Contact | ||
|
|
||
Highly Aggressive (highly + aggressive)
Selected AbstractsThe Association Between Male Offspring Aggression and Paternal and Maternal Behavior of Peromyscus MiceETHOLOGY, Issue 10 2003Janet K. Bester-Meredith Parents influence offspring aggression through genetic and non-genetic mechanisms, although the latter are less well understood. To examine potential non-genetic effects of parents on offspring, we cross-fostered the highly aggressive and biparental California mouse (Peromyscus californicus) and the less aggressive, less parental white-footed mouse (Peromyscus leucopus). In-fostered animals within each species were used as controls. We examined associations between the foster parents' behavior and aggression of the fostered male offspring in resident,intruder (R,I) and neutral arena aggression tests. When both species and fostering groups were combined, R,I aggression of offspring was positively associated with paternal time spent retrieving pups. In contrast, aggression in a neutral arena was negatively associated with a composite score of maternal behavior. We discuss how our findings regarding paternal retrievals may explain previously reported effects of cross-fostering on male aggression. [source] Variation in Aggressiveness of Stagonospora nodorum Isolates in North DakotaJOURNAL OF PHYTOPATHOLOGY, Issue 3 2008S. Ali Abstract Stagonospora nodorum blotch (SNB), caused by Stagonospora nodorum, is an important disease in the northern Great Plains of the United States and in other wheat-producing regions in the world. SNB can be managed by different strategies including the use of resistant cultivars. Genetic variation in the pathogen populations is one of the important factors in the development of durable resistant cultivars. Our main objective was to determine variation in aggressiveness/virulence in the 40 isolates of S. nodorum collected from various locations in North Dakota. To achieve this goal, we tested the isolates on two susceptible wheat cultivars (cvs ,ND495' and ,Alsen') and two resistant wheat cultivars (cvs ,Erik' and ,Salamouni') , two-leaf-stage seedlings under controlled conditions. Aggressiveness of each isolate was characterized by the two epidemiological parameters: percent necrotic leaf area (% NLA) and lesion type (LT) 8 days post-inoculation. The isolates differed significantly (P , 0.05) for % NLA and LT, and were grouped into three aggressiveness groups (AG): low, medium and highly aggressive. Four isolates (S50, S57, S66 and S89) induced 18,26% NLA and were included into the low aggressive group (AG 1). Three isolates (S15, S39 and S89) induced 57,59% NLA and were considered highly aggressive (AG 3). Thirty-three isolates were medium aggressive (AG 2). No relationship between AG and mating types was observed. There were significant (P , 0.05) differences in % NLA and LT among wheat cultivars. Significant wheat cultivars by isolates interaction was also demonstrated, suggesting evidence for the existence of host specificity in this system. Overall, our results indicate that S. nodorum isolates prevalent in North Dakota varied greatly in their aggressiveness and that AG 3 isolates can be utilized in breeding wheat for resistance to SNB. [source] REVIEW ARTICLE: Cancer stem cells and human malignant melanomaPIGMENT CELL & MELANOMA RESEARCH, Issue 1 2008Tobias Schatton Summary Cancer stem cells (CSC) have been identified in hematological malignancies and several solid cancers. Similar to physiological stem cells, CSC are capable of self-renewal and differentiation and have the potential for indefinite proliferation, a function through which they may cause tumor growth. Although conventional anti-cancer treatments might eradicate most malignant cells in a tumor, they are potentially ineffective against chemoresistant CSC, which may ultimately be responsible for recurrence and progression. Human malignant melanoma is a highly aggressive and drug-resistant cancer. Detection of tumor heterogeneity, undifferentiated molecular signatures, and increased tumorigenicity of melanoma subsets with embryonic-like differentiation plasticity strongly suggest the presence and involvement of malignant melanoma stem cells (MMSC) in the initiation and propagation of this malignancy. Here, we review these findings in the context of functional properties ascribed to melanocyte stem cells and CSC in other cancers. We discuss the association of deregulated signaling pathways, genomic instability, and vasculogenic mimicry phenomena observed in melanoma subpopulations in light of the CSC concept. We propose that a subset of MMSC may be responsible for melanoma therapy-resistance, tumor invasiveness, and neoplastic progression and that targeted abrogation of a MMSC compartment could therefore ultimately lead to stable remissions and perhaps cures of metastatic melanoma. [source] Effect of the Rht-D1 dwarfing locus on Fusarium head blight rating in three segregating populations of winter wheatPLANT BREEDING, Issue 4 2008H.-H. Voss Abstract Fusarium head blight (FHB) is one of the major fungal diseases in wheat throughout the world. To control FHB severity, breeding genetically resistant varieties is thought to be the most promising strategy. In wheat breeding programmes, short cultivars predominantly carrying the Norin 10 derived semi-dwarfing allele Rht-D1b (Rht2) are preferred worldwide because of higher achievable grain yields and lower risk of lodging. This study was conducted to determine the influence of different alleles at the Rht-D1 locus on FHB reaction. Three winter wheat populations were produced by crossing rather susceptible varieties ,Biscay', ,Pirat' and ,Rubens' carrying mutant-type allele Rht-D1b with the more resistant varieties ,Apache', ,Romanus' and ,History' containing the Rht-D1a wild-type allele (rht2). The 190, 216 and 103 progeny of the F4 -derived populations were assayed for the presence of Rht-D1a or Rht-D1b, plant height, and mean FHB rating after spray inoculation at flowering time with a highly aggressive isolate of Fusarium culmorum. Comparably, high mean FHB severities ranging from 28% to 49% for all population × environment combinations were achieved, with significant genotypic variation for FHB rating and plant height within all populations. Both traits were negatively correlated with r ranging from ,0.48 to ,0.61 in the complete populations. However, within the subpopulations homozygous for one or other height allele these correlations decreased considerably. The Rht-D1b semi-dwarfing allele resulted in 7,18% shorter plants, depending on the population, but a considerably increased FHB reaction of 22,53%. Nevertheless, significant genotypic variance for FHB resistance remained in all tested Rht-D1b subpopulations indicating that selection for moderately FHB resistant genotypes within agronomically beneficial Rht-D1b genotypes is still feasible. [source] Pleuropulmonary complications of PVL-positive Staphylococcus aureus infection in childrenACTA PAEDIATRICA, Issue 8 2009Biju Thomas Abstract It is increasingly recognized world-wide that Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus (PVL-SA) is associated with a highly aggressive and often fatal form of community-acquired pneumonia. We report four children who presented with severe pleuropulmonary complications due to infection by community-acquired methicillin-sensitive S. aureus (CA-MSSA), producing PVL toxin. The complications included bilateral multilobular infiltrates, pneumatocoeles, recurrent pneumothoraces, pleural effusion, empyema, lung abscess and diaphragmatic paralysis. This case series highlights the diverse pleuropulmonary manifestations of this potentially lethal infection and the importance of heightened awareness, early recognition and aggressive therapy. Conclusion:, Complicated pneumonia in a previously fit young patient with a history of preceding ,flu-like' illness or skin/soft tissue infection should raise the suspicion of infection by PVL-positive Staphylococcus aureus (PVL-SA). Severe pleuropulmonary complications are a feature of this disease. [source] | ||||||||||