Purification and characterization of trans-permethrin metabolizing microsomal esterases from workers of the eastern subterranean termite, Reticulitermes flavipes (Kollar)

Three alpha-naphthyl acetate hydrolyzing esterase isozymes were purified from microsomes prepared from Reticulitermes flavipes workers. The two step process involved sequential preparative IEF followed by continuous elution preparative electrophoresis on a 5% non-denaturing polyacrylamide gel. The first IEF run resulted in 5.4-fold purification with a yield of 46.1%. Subsequent IEF further purified the esterases 14.3-fold and 12% yield. Preparative electrophoresis of the pooled IEF fractions produced three major peaks of alpha-naphthyl acetate hydrolyzing activity. The esterases were correspondingly designated microsomal esterase (ME) 1, ME 2, and ME 3 based on increasing molecular retention on a native PAGE gel. ME 1, ME 2, and ME 3 were acidic proteins with pI values of 4.61, 4.70, and 4.77, respectively. Molecular mass as determined by gel filtration chromatography of ME 1, ME 2, and ME 3 was 69, 64, and 62 kDa, respectively. SDS-PAGE gels produced a single band for each of the isozymes with a molecular mass of 63 kDa indicating that the esterases were monomers. Specific activities of ME 1, ME 2, and ME 3 increased with increasing pH and the enzymes were active over a broad temperature range (25-55 degrees C). The three purified isozymes were inhibited at low concentration by paraoxon (10(-10) M), chlorpyrifos (10(-6) M), DEF (10(-6) M), and PMSF (10(-6) M) indicating that they were "B" type serine esterases. Conversely, inhibition was not observed at 10(-4) M eserine, PHMB, or CaCl(2), further supporting the conclusion that the microsomal esterases were of the "B" type. None of the isozymes was inhibited by 10(-4) M imidacloprid, fipronil, or PBO. Quantitatively, ME 1, ME 2 and ME 3 metabolized t-permethrin at 21.8, 21.0, and 38.8 nmol/h/mg protein, representing a purification factor of 333-, 318-, and 591-fold over microsomes, respectively. The three isozymes produced the same type and number of t-permethrin metabolites.

Comparison of Recovery of Anaerobic Bacteria Using the Anoxomat®, Anaerobic Chamber, and GasPak®Jar Systems

The Anoxomat system provides an automated evacuation-replacement technique to create an anaerobic or microaerophilic environment in a jar. We evaluated the Anoxomat system for the growth of obligate anaerobes and for the recovery of anaerobic organisms from clinical specimens, and compared its performance to that of an anaerobic chamber and the GasPak System. Of the 54 stock strains tested, the Anoxomat, the chamber, and the GasPak recovered 95%, 95% and 93% at 24 h, respectively. On 29 occasions (51%), the colonies on the Anoxomat plates were slightly larger than those in the chamber and on 17 (30%) occasions larger than the colonies on the GasPak jar plates. At 48 h, the Anoxomat, the chamber, and the GasPak recovered 93.5%, 94.4% and 88.9%, respectively; of 108 anaerobes isolated from 31 clinical specimens. Methylene blue indicators became decolorized (average of 10 tests) within 2 h inside the Anoxomat jars, 2 h 10 min inside the anaerobic chamber, and 2 h 30 min inside the GasPak jars.

Survival of anaerobes in original specimens transported by overnight mail services

Overnight mail delivery was evaluated for its effect on the recovery of facultative and anaerobic microbes in cultures of clinical specimens from patients. Ten clinical specimens, which were collected at different geographic locations and during different weather conditions, were cultured at the site and after overnight delivery to a distant laboratory. Forty-five facultative anaerobic isolates and 48 anaerobes were recovered. There was no significant difference in numbers of strains or relative quantities recovered in cultures of transported and nontransported specimens. With proper collection, transport, and inoculation of specimens, overnight delivery did not compromise recovery of clinically relevant microbes.

Rearing improvements for the German cockroach (Dictyoptera: Blattellidae)

Known-age cohorts of three strains of German cockroach, Blattella germanica (L.), were mass-reared by establishing one rearing container each week (so that cockroaches within a container would be of known age). An average of 330-443 females was placed in oviposition units within these rearing containers. Percentage hatch of oothecae was 77.49-84.63%, resulting in an average of 12,258-16,359 nymphs per rearing container. Development of nymphs was similar for the three strains. Survivorship of nymphs to the adult stage was 19.95-29.56%; survivorship was significantly higher for the strain most recently colonized from the field. Adult emergence occurred at 6-7 wk, and average production per container was 2,834-3,971 cockroaches.

Harborage width preferences of German cockroach (Dictyoptera: Blattellidae) adults and nymphs

Adults and nymphal cohorts of the German cockroach, Blattella germanica (L.), were allowed 24 h to select preferred harborage widths from eight harborages between 1.59 and 12.72 mm (increments of 1.59 mm) in both individual and combined cohort studies. In individual cohort studies, 1- and 2-wk-old nymphs significantly preferred 1.59-mm-wide harborage, with 74 and 68%, respectively; 3- and 4-wk-old nymphs significantly preferred 3.18-mm-wide harborage, with 63 and 45%, respectively; 5-wk-old nymphs selected the 4.77-mm-wide harborage; and 6-wk-old nymphs were evenly distributed in 3.18- to 9.54-mm-wide harborages. Males were in 6.36- to 12.72-mm-wide harborages. Nongravid females (81%) were in 4.77-, 6.36-, and 11.13-mm-wide harborages; gravid females (94%) preferred 4.77- and 6.36-mm-wide harborages. The percentage of nymphs outside harborages decreased as cockroach age increased from 1 to 5 wk. In combined cohort studies, preferred harborage widths for all cohorts and sexes were 6.36-7.95 mm and 11.13-12.72 mm. The percentage of nymphs outside harborages was low and constant (< 4.57%) irrespective of age or sex.

Oral toxicity and repellency of borates to German cockroaches (Dictyoptera: Blattellidae)

The oral toxicities of boric acid and disodium octaborate tetrahydrate (DSOBTH) in dry-mixed, wet-mixed, and water-based solution baits were determined for German cockroaches, Blattella germanica L., in choice and nonchoice experiments. In dry-mixed, nonchoice bait tests, all cockroaches died within 1 wk. Time to mortality decreased as the concentration of boric acid increased. The LT50s for DSOBTH were not significantly different for any concentrations tested. In choice tests, the order of LT50s of boric acid and DSOBTH were 6.25% = 12.5% > 25% = 50% and 25% > 12.5% > 50% > 25%, respectively. Consumption of treated and control baits and the differences between the LT50s of the nonchoice and choice tests indicate repellency of the toxicants. Most German cockroaches died in 3-6 d in wet-mixed nonchoice tests, but all cockroaches survived the wet-mixed choice tests except at the lowest concentration of boric acid. This result indicated repellency. In nonchoice tests with water-based solutions, all cockroaches died in 5 d. In choice tests with boric acid solutions, mortality did not increase at concentrations > 1%. Choice/nonchoice ratios indicate no repellency of water-based solutions. In addition, consumption of treated and blank solutions was not significantly different for any concentration except 4% DSOBTH.

Comparison of the Accu-CulShure system and a swab placed in a B-D Port-a-Cul tube for specimen collection and transport

We compared the Accu-CulShure guarded specimen collection device and a swab inserted into a B-D Port-a-Cul transport tube in terms of their efficacy under ideal conditions for recovery of bacteria from 10 decubitus ulcer specimens. Cultures yielded 57 aerobes and 21 anaerobes; 76 isolates were recovered with use of Accu-CulShure, and 72 isolates were recovered with use of Port-a-Cul. Both systems were comparable for recovery of organisms in terms of quantitative and qualitative results.

Bacteriology of anaerobic pleuropulmonary infections: preliminary report

A retrospective bacteriologic study of anaerobic pleuropulmonary infections diagnosed at the Wadsworth Veterans Affairs Medical Center between 1976 and 1991 was performed. There were 116 specimens from 110 patients. Available strains were reexamined using the latest tests and taxonomic schemes. Pleural fluid was believed to provide the most reliable specimen; cultures yielded an average of 3.0 anaerobes and 0.6 nonanaerobes per specimen. The most commonly encountered anaerobes were pigmented Prevotella species, nonpigmented Prevotella species, Fusobacterium nucleatum, Peptostreptococcus species, and Bacteroides species. Thirty percent of the anaerobic gram-negative rods were beta-lactamase producers.

UV red fluorescence of Eubacterium lentum

Twenty-nine clinical isolates of Eubacterium lentum and two type species were evaluated for the ability to fluoresce under UV light. Twenty-one of the 29 isolates and both of the reference strains showed orange-to-red fluorescence. This fluorescence did not require blood or hemin in the culture media and did not fade upon air exposure. The fluorescent pigment, after extraction by 1 N NaOH, showed peak excitation at a wavelength of around 400 nm. The capacity of E. lentum to produce fluorescence may be a useful and time-sparing laboratory aid for its identification.

The importance of black-pigmented gram-negative anaerobes in human infections

Black-pigmented Gram-negative anaerobic rods are found on mucosal surfaces as indigenous flora. With mucosal damage due to disease, trauma or surgery, these organisms may invade tissues and set up infection. Other important factors determining whether or not infection results include 'inoculum' size, synergy with other organisms and production of virulence factors that include capsules, lipopolysaccharide, attachment factors, proteases, collagenase, neuraminidase, and phospholipase A; also, they may have fibrinolytic and anti-phagocytic activity and may degrade complement and IgG and IgM. Pigmented anaerobes are found in all types of infections including such serious infections as bacteraemia, endocarditis, intracranial abscess, necrotizing pneumonia and necrotizing fasciitis, generally as part of a mixed infecting flora, and they play a key role in experimental mixed infections. They dominate or are prominent in infections involving organisms originating in the oropharynx, such as central nervous system, head and neck, dental and pleuropulmonary infections. Therapy of infections involving pigmented anaerobes includes surgery plus antimicrobial agents; a significant percentage of strains produce beta-lactamase. Much remains to be done to determine the relative importance of the various taxa of black-pigmented Gram-negative anaerobes and of the different virulence factors produced by them.

Bilophila wadsworthia isolates from clinical specimens

Bilophila wadsworthia is an anaerobic, gram-negative, asaccharolytic, bile-resistant, catalase-positive bacillus that is usually urease positive and was originally recognized in specimens of peritoneal fluid and tissue from patients with appendicitis. Additional isolations from clinical specimens, including a scrotal abscess, mandibular osteomyelitis, axillary hidradenitis suppurativa, pleural fluid, joint fluid, and blood, are described here.

Stepwise correction of anaemia by subcutaneous administration of human recombinant erythropoietin in patients with chronic renal failure maintained by continuous ambulatory peritoneal dialysis

Sixteen anaemic CAPD patients (Hb less than 9 g/dl) were treated with thrice-weekly subcutaneous recombinant erythropoietin, epoetin-alfa. The dose was adjusted to induce a stepwise increase in haemoglobin. Fourteen patients reached a first target haemoglobin of 11.0-11.5 g/dl and eight of these a second of 13.0-13.5 g/dl, but one could not be maintained at this level. Failure to reach or maintain the second target in nine subjects was accounted for by incomplete responses associated with infection in one, extreme shortening of red-cell survival in another, and was unexplained in one subject. These three received the maximum dose studied of 450 IU/kg per week. Six other subjects were withdrawn from the study for reasons unrelated to treatment with erythropoietin. The median dose required to maintain the haemoglobin at 11.0-11.5 g/dl was 75 IU/kg per week and at 13.0-13.5 g/dl was 150 IU/kg per week. Quality of life, assessed in 12 patients at haemoglobin 11.0-11.5 g/dl, showed significant improvement in energy, and at 13.0-13.5 g/dl improvements in sleep and emotional wellbeing became significant. Twelve subjects required either institution of, or an increase in, treatment for hypertension. The thrice-weekly subcutaneous doses of erythropoietin were well tolerated and were a convenient and effective treatment for anaemia in patients on CAPD.

Comparison of two commercial enzyme-linked immunosorbent assays for detection of herpes simplex virus antigen

Two commercial enzyme-linked immunosorbent assays (ELISA) for detection of herpes simplex virus (HSV) antigen in direct clinical specimens were compared with cell culture in primary rabbit kidney and MRC-5. With a total of 238 specimens, the sensitivity and specificity of the Dako ELISA method were determined to be 70.1% and 82.4%, respectively, and 60.4% and 88.2%, respectively, for the Ortho Antigen ELISA.

Enhanced virus isolation by use of the transporter for a regional laboratory

Transporter tubes with fibroblast monolayers were compared with sucrose-phosphate-glutamate buffer for transport of 385 specimens to a regional laboratory for virus culture. Ninety-two (91%) of 101 viral isolates were recovered in cell culture from the Transporter, as compared with 82 (81%) from sucrose-phosphate-glutamate buffer. Twenty-five (24.7%) of the viral isolates were detected by cytopathic effect from 1 to 11 days earlier from the Transporter than from the sucrose-phosphate-glutamate buffer. The Transporter also permitted the use of ambient temperature for transport.