Distribution of Fusarium wilt of Bambara nut (Vigna subterranea (L.) Verdc.) in farmers’ fields’ of Busia County in Western Kenya and its management using farmyard manure

A study was carried out to determine Fusarium wilt distribution in Bambara nut farmers’ fields and its management using farm yard manure (FYM). Four villages in Busia County were purposively sampled for the study. The data generated were subjected to analysis of variance and treatment means separated by least significant difference test. Fusarium wilt incidence in the fields ranged from 14.63 to 43.56%. In the greenhouse, FYM reduced the disease incidence by 10.2% and severity by 9.5% on the black landrace and 1.9 and 12.8%, respectively, on the red landrace. In the field, FYM reduced disease incidence by 9.1% and severity by 6.9% on the black landrace and 10.4 and 10.4%, respectively, on the red landrace. Farm yard manure had the lowest area under disease progress curve irrespective of the landrace. The study confirmed the presence of the pathogen in the fields and the ability to manage the disease using FYM.     

The Heat-Resistant Agglutinin Family Includes a Novel Adhesin from Enteroaggregative Escherichia coli Strain 60A

Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen for the associated genes and found that they occur among 55 (36.7%) of the enteroaggregative E. coli isolates screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohemorrhagic, and commensal E. coli isolates. Overall, 25%, 8%, and 3% of 150 EAEC strains harbored hra1 alone, tia alone, or both genes, respectively. One EAEC isolate, 60A, produced an amplicon with a unique restriction profile, distinct from those of hra1 and tia. We cloned and sequenced the full-length agglutinin gene from strain 60A and have designated it hra2. The hra2 gene was not detected in any of 257 diarrheagenic E. coli isolates in our collection but is present in the genome of Salmonella enterica serovar Heidelberg strain SL476. The cloned hra2 gene from strain 60A, which encodes a predicted amino acid sequence that is 64% identical to that of Hra1 and 68% identical to that of Tia, was sufficient to confer adherence on E. coli K-12. We constructed an hra2 deletion mutant of EAEC strain 60A. The mutant was deficient in adherence but not autoaggregation or invasion, pointing to a functional distinction from the autoagglutinin Hra1 and the Tia invasin. Hra1, Tia, and the novel accessory adhesin Hra2 are members of a family of integral outer membrane proteins that confer different colonization-associated phenotypes.     

Physical maturity in common bottlenose dolphins (Tursiops truncatus) from Sarasota Bay,Florida

Cetacean physical maturity is defined by growth cessation and complete fusion of epiphyses to vertebral bodies indicated by invisible sutures. Many studies have shown epiphyseal fusion is highly variable among individuals. In-depth examinations into fusion variability are lacking. We analyzed vertebrae of 37 (n = 21 female, n = 16 male) stranded common bottlenose dolphins (Tursiops truncatus) from the well-studied Gulf of Mexico, Sarasota Bay community. For each specimen, vertebrae were examined by vertebral region for degree of fusion anteriorly and posteriorly of each centrum and categorized from unfused to fused in five degrees. An ordinal logistic regression was used to estimate degree of fusion probability for each epiphysis. The model had fixed effects for age, number of offspring, sex, sexual maturity, and a random effect for epiphysis. Results show that age/reproductive status significantly explains an individual's degree of fusion. Adult females with fewer calves had more fusion than those with more reproductive experience across multiple ages. Access to long-term observational and sample data on the dolphins residing in the area served by Mote Marine Laboratory's Stranding Investigations Program offers a unique opportunity to examine the relationship between energetic demands of reproduction (calcium production/reproductive output) versus preconceived definitions of physical maturity (skeletal fusion) more closely.     

Comparison of 26 Sphingomonad Genomes Reveals Diverse Environmental Adaptations and Biodegradative Capabilities

Sphingomonads comprise a physiologically versatile group within the Alphaproteobacteria that includes strains of interest for biotechnology, human health, and environmental nutrient cycling. In this study, we compared 26 sphingomonad genome sequences to gain insight into their ecology, metabolic versatility, and environmental adaptations. Our multilocus phylogenetic and average amino acid identity (AAI) analyses confirm that Sphingomonas, Sphingobium, Sphingopyxis, and Novosphingobium are well-resolved monophyletic groups with the exception of Sphingomonas sp. strain SKA58, which we propose belongs to the genus Sphingobium. Our pan-genomic analysis of sphingomonads reveals numerous species-specific open reading frames (ORFs) but few signatures of genus-specific cores. The organization and coding potential of the sphingomonad genomes appear to be highly variable, and plasmid-mediated gene transfer and chromosome-plasmid recombination, together with prophage- and transposon-mediated rearrangements, appear to play prominent roles in the genome evolution of this group. We find that many of the sphingomonad genomes encode numerous oxygenases and glycoside hydrolases, which are likely responsible for their ability to degrade various recalcitrant aromatic compounds and polysaccharides, respectively. Many of these enzymes are encoded on megaplasmids, suggesting that they may be readily transferred between species. We also identified enzymes putatively used for the catabolism of sulfonate and nitroaromatic compounds in many of the genomes, suggesting that plant-based compounds or chemical contaminants may be sources of nitrogen and sulfur. Many of these sphingomonads appear to be adapted to oligotrophic environments, but several contain genomic features indicative of host associations. Our work provides a basis for understanding the ecological strategies employed by sphingomonads and their role in environmental nutrient cycling.     

Immunology of pregnancy: cellular mechanisms allowing fetal survival within the maternal uterus

Pregnancy success remains a fascinating phenomenon to immunologists as it defies the immunological rules of rejection. Although it was previously thought that the maternal immune system does not see the fetus, it is now well documented that fetal cells reach the maternal body and encounter host immune cells. Natural tolerance mechanisms following this interaction remain to be fully elucidated. This article reviews the current literature on mechanisms of adaptive immunity, with emphasis on regulatory T cells and heme oxygenase 1 (HO-1). We propose a scenario in which regulatory T cells create a tolerant microenvironment at the fetal-maternal interface characterised by the presence of tolerance-associated molecules such as HO-1, which has been shown to be of vital importance for fetal survival.     

Managing the 2004/05 anthrax outbreak in Queen Elizabeth and Lake Mburo National Parks, Uganda

In August 2004, hippo mortality in the waters of Kazinga Channel, Lakes George and Edward within Queen Elizabeth National Park (QENP) was observed. Veterinary investigation confirmed the disease killing hippos to be anthrax, using clinical, postmortem and laboratory diagnosis, including the polymerase chain reaction technique. Anthrax is believed to have occurred in QENP in 1959, 1962 and 1991 amongst Hippopotamus amphibious but these was not as devastating as the outbreak of 2004–2005. During the outbreak, 306 hippopotami representing 11.63%, 63 zebras representing 1.47%, 60 buffaloes representing 0.9%, thirteen warthogs representing 0.69%, twelve kobs representing 0.07%, three waterbucks representing 0.09% and five elephants representing 0.02% died. A multisectoral National Taskforce was set up, to among other things contain the disease at source and halt its spread. Carcass disposal by burying and burning, decontamination of disposal sites by 10% formaldehyde, ring vaccination of cattle and sheep using blanthrax vaccine and community sensitization, were carried out by the taskforce. A surveillance programme is in place.     

Force Generation via β-Cardiac Myosin,Titin, and α-Actinin Drives Cardiac Sarcomere Assembly from Cell-Matrix Adhesions

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Antimicrobial Resistance and Virulence Genes of Escherichia coli Isolates from Swine in Ontario

A total of 318 Escherichia coli isolates obtained from diarrheic and healthy pigs in Ontario from 2001 to 2003 were examined for their susceptibility to 19 antimicrobial agents. They were tested by PCR for the presence of resistance genes for tetracycline, streptomycin, sulfonamides, and apramycin and of 12 common virulence genes of porcine E. coli. Antimicrobial resistance frequency among E. coli isolates from swine in Ontario was moderate in comparison with other countries and was higher in isolates from pigs with diarrhea than in isolates from healthy finisher pigs. Resistance profiles suggest that cephamycinases may be produced by ≥8% of enterotoxigenic E. coli (ETEC). Resistance to quinolones was detected only in enterotoxigenic E. coli (≤3%). The presence of sul3 was demonstrated for the first time in Canada in porcine E. coli isolates. Associations were observed among tetA, sul1, aadA, and aac(3)IV and among tetB, sul2, and strA/strB, with a strong negative association between tetA and tetB. The paa and sepA genes were detected in 92% of porcine ETEC, and strong statistical associations due to colocation on a large plasmid were observed between tetA, estA, paa, and sepA. Due at least in part to gene linkages, the distribution of resistance genes was very different between ETEC isolates and other porcine E. coli isolates. This demonstrates that antimicrobial resistance epidemiology differs significantly between pathogenic and commensal E. coli isolates. These results may have important implications with regards to the spread and persistence of resistance and virulence genes in bacterial populations and to the prudent use of antimicrobial agents.     

Measurement of mitochondrial DNA synthesis in vivo using a stable isotope-mass spectrometric technique.

We describe here a new stable isotope-mass spectrometric technique for measuring mitochondrial DNA (mtDNA) synthesis. Growing (2-4 mo old) and weight-stable (8-10 mo old) Sprague-Dawley rats were primed with (2)H(2)O (deuterated water) to 2.0-2.5% body water enrichment, via intraperitoneal injection, and then given 4% (2)H(2)O in drinking water for 3-11 wk. Mitochondria were isolated from cardiac and hindlimb muscle, and mtDNA was isolated and enzymatically hydrolyzed to deoxyribonucleosides. PCR confirmed the absence of nuclear DNA contamination. The isotopic enrichment of the deoxyribose moiety of deoxyadenosine was determined by GC-MS analysis, and percent new mtDNA was calculated by comparison to genomic DNA enrichments in a tissue with nearly complete turnover (bone marrow). Initial label incorporation into deoxyadenosine of mtDNA was linear, and turnover of mtDNA was observed in nongrowing adult female rats (1.1-1.3% new mtDNA per day in cardiac and skeletal muscle). Die-away curves of mtDNA after discontinuing (2)H(2)O administration gave a similar turnover rate constant. Human subjects were also given (2)H(2)O for up to 6 wk, and mitochondria from platelets were isolated. Incubation with DNase removed any contaminating genomic DNA; platelet mtDNA exhibited linear incorporation from (2)H(2)O and reached plateau values identical to those in genomic DNA from fully turned over cells (circulating monocytes). In conclusion, replication of mtDNA can be directly measured in vivo in rodents and humans without the use of radioactivity. Use of this technique may allow improved understanding of the regulation of mitochondrial biogenesis in health and disease.