S. typhimurium nit mutants are defective in nitrogen assimilation, despite having normal levels of assimilatory enzymes. Complementation, enzyme assays, and genetic mapping show that nit is nadE. We present evidence that ammonia, not glutamine, is the physiological substrate for eubacterial NAD synthetases and that low activity completely accounts for the mutant phenotype.

Recently, we defined the nitrilase superfamily as consisting of 12 families of amidases, N-acyltransferases and presumptive amidases, in addition to the family of plant and bacterial nitrilases for which the superfamily was named. A novel Glu-Lys-Cys catalytic triad, found at the crystallographically defined Nit active site of worm NitFhit, was postulated to constitute the catalytic residues fo...

Clothing use is an important modern behavior that contributed to the successful expansion of humans into higher latitudes and cold climates. Previous research suggests that clothing use originated anywhere between 40,000 and 3 Ma, though there is little direct archaeological, fossil, or genetic evidence to support more specific estimates. Since clothing lice evolved from head louse ancestors on...

Section of Preventive Medicine and Epidemiology, Evans Department of Medicine, Clinical Epidemiology Research and Training nit, Clinical Addiction Research and Education Unit, Section of General Internal Medicine, Department of Medicine, Boston niversity School of Medicine and Boston Medical Center, Mass; Department of Epidemiology and Youth Alcohol Prevention Cent oston University School of Pu...

BACKGROUND Pediculosis (head lice) is considered as one of the most common health problems of the students in primary schools. The purpose of this study was to survey the prevalence rate of the infestation in the schools of Gonabad City (south of Khorasan-e-Razavi Province) to prevent its outbreak by on-time planning. METHODS In this retrospective-descriptive study, data were collected from t...

The domestic fly (Musca domestica) can carry the virus of poliomyelitis in an active state for several days upon the surface of the body and for several hours within the gastro-intestinal tract. Mosquitos (Culex pipiens, Culex sollicitans, and Culex cantator), in our experiments, have not taken up and maintained in a living state the virus from the spinal cord of monkeys. Lice (Pediculus capiti...

Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial clades (A, D, B, F, C and E). Several studies reported presence of different pathogenic agents lice specimens collected worldwide. These findings suggest louse could be a dangerous vector serious public health problem. Herein, we aimed to study genetic diversity, PHUM5...