The cel4 gene of Agaricus bisporus encodes a beta-mannanase.

Mannases have industrial uses in food and pulp industries, and their regulation may influence development of the mushrooms of commercially important basidiomycetes. We expressed an Agaricus bisporus cel4 cDNA, which encodes a mannanase, in Saccharomyces cerevisiae and Pichia pastoris. CEL4 had no detectable activity on cellulose or xylan. This gene is the first isolated from this economically important fungus to encode a mannanase. P. pastoris secreted about three times more CEL4 than S. cerevisiae. The removal of the cellulose-binding domain of CEL4 lowered the secreted specific activity by P. pastoris by approximately 97%. The genomic sequence of cel4 was isolated by screening a cosmid library of A. bisporus C54-carb8. The open reading frame was interrupted by 12 introns. The level of extracellular CEL4 increases dramatically at the postharvest stage in compost extracts of A. bisporus fruiting cultures. In laboratory liquid cultures of A. bisporus, the activity of CEL4 detected in the culture filtrate reached a maximum after 21 days. The levels of CEL4 broadly mirrored the levels of enzyme activity. In the Solka floc-bound mycelium, CEL4 protein showed a maximum after 2 to 3 weeks of culture and then declined. Changes in CEL4 activity during fruiting-body development suggest that hemicellulose utilization plays an important role in sporophore formation. The availability of the cloned gene will further studies of compost decomposition and the extracellular enzymes that fungi deploy in this process.

Surveillance of leptospiral carriage by feral rats in Barbados.

Rodents, particularly rats, are widely held to be the source of most human cases of leptospirosis. Feral rats were trapped at sites throughout Barbados during two six month surveys: from October to March 1986/87 and from October to March 1994/95. During the first survey, 63 rats were trapped, of which 26 (41%) were identified as Rattus rattus and 37 (59%) as Rattus norvegicus. In the second study, 100 rats were trapped, of which R. rattus comprised 24% (24) and R. norvegicus 76% (76). Cultures of blood, urine and kidney were made in EMJH medium. Leptospires were isolated from 12/63 (19%) and from 16/100 (16%) of the rats during 1986/87 and 1994/95, respectively; 27/28 isolates were recovered from the kidneys or urine or both, while only one isolate was recovered from the blood. During the first study, isolates were identified as serovars copenhageni (11) and arborea (1), while in the second study, serovars copenhageni (9), arborea (5) and bim (1) were identified; one isolate was lost before it could be identified. In the first study, antibodies were detected by microscopic agglutination at a titre of > or = 100 in 26/62 (42%) of rats tested, while in the second survey, 5/100 (5%) of rats had similar titres. In two surveys, conducted eight years apart, we confirmed that rats in Barbados are commonly infected with leptospires, and that viable organisms are found in the kidneys and urine, evidence of chronic infection and thus excretion of leptospires in rodent urine. Moreover, the predominant serovar isolated was copenhageni, of which Rattus spp. are the worldwide reservoir. There was little evidence that rats act as a reservoir for the serovar bim, the most common cause of human leptospirosis in Barbados.

Surveillance of leptospiral carriage by feral rats in Barbados

Rodents, particularly rats, are widely held to be the source of most human cases of leptospirosis. Feral rats were trapped at sites throughout Barbados during two-six month surveys: from October to March 1986/87 and from October to March 1994/95. During the first survey, 63 rats were trapped, of which 26 (41 percent) were identified as Rattus rattus and 37 (59 percent) as Rattus norvegicus. In the second study, 100 rats were trapped, of which R. rattus comprised 24 percent (24) and R. norvegicus 76 percent (76). Cultures of blood, urine and kidney were made in EMJH medium. Leptospires were isolated from 12/63 (19 percent) and from 16/100 (16 percent) of the rats during 1986/87 and 1994/95, respectively; 27/28 isolates were recovered from the kidneys or urine or both, while only one isolate was recovered from the blood. During the first study, isolates were identified as serovars copenhageni (11), arborea (1), while in the second study, serovars copenhageni (9), arborea (5) and bim (1) were identified; one isolate was lost before it could be identified. In the first study, antibodies were detected by microscopic agglutination at a titre of > or = 100 in 26/62 (42 percent) of rats tested, while in the second survey, 5/100 (5 percent) of rats had similar titres. In two surveys, conducted eight years aparts we confirmed that rats in Barbados are commonly infected with leptospires, and that viable organisms are found in the kidneys and urine, evidence of chronic infection and thus excretion of leptospires in rodent urine. Moreover, the predominant serovar isolated was copenhageni, of which Rattus spp. are the worldwide reservoir. There was little evidence that rats act as a reservoir for the serovar bim, the most common cause of human leptospirosis in Barbados.(AU)

Surveillance of leptospiral carriage by feral rats in Barbados

Rodents, particularly rats, are widely held to be the source of most human cases of leptospirosis. Feral rats were trapped at sites throughout Barbados during two six month surveys: from October to March 1986/87 and from October to March 1994/95. During the first survey, 63 rats were trapped, of which 26 (41) were identified as Rattus rattus and 37 (59) as Rattus norvegicus. In the second study, 100 rats were trapped, of which R. rattus comprised 24(24) and R. norvegicus 76(76). Cultures of blood, urine and kidney were made in EMJH medium. Leptospires were isolated from 12/63 (19) and from 16/100 (16) of the rats during 1986/87 and 1994/95, respectively; 27/28 isolates were recovered from the kidneys or urine or both, while only one isolate was recovered from the blood. During the first study, isolates were identified as serovars copenhageni (11) and arborea (1), while in the second study, serovars copenhageni (9), arborea (5) and bim (1) were identified; one isolate was lost before it could be identified. In the first study, antibodies were detected by microscopic agglutination at a titre of > or = 100 in 26/62 (42) of rats tested, while in the second survey, 5/100 (5) of rats had similar titres. In two surveys, conducted eight years apart, we confirmed that rats in Barbados are commonly infected with leptospires, and that viable organisms are found in the kidneys and urine, evidence of chronic infection and thus excretion of leptospires in rodent urine. Moreover, the predominant serovar isolated was copenhageni, of which Rattus spp. are the worldwide reservoir. There was little evidence that rats act as a reservoir for the serovar bim, the most common cause of human leptospirosis in Barbados.

Surveillance of leptospiral carriage in feral rats in Barbados - abstract

Rodents, particularly rats, are widely held to be the source of most human cases of leptospirosis. Feral rats were trapped at sites throughout the island of Barbados during two six month surveys, from October - March 1986/87 and 1994/95. During the first survey, 63 rats were trapped, of which 26 (41 percent) were identified as Rattus rattus and 37 (59 percent) as Rattus norvegicus. In the second study, 100 rats were trapped, of which R. rattus comprised 24 percent (24) and R. norvegicus 76 percent (76). Cultures of blood, urine and kidney were made in EMJH medium. Leptospira were isolated from 12/63 (19 percent) and from 16/100 (16 percent) of the rats during 1986/87 and 1994/95, respectively; 27/28 isolates were recovered from the kidneys or urine or both, while only one isolate was recovered from blood. During the first study, isolates were identified as serovars copenhageni (11) and arborea (1), while in the second study, serovars copenhageni (9), arborea (5) and bim (1) were identified; one isolate was lost before it could be identified. In the first study, antibodies were detected by microscopic agglutination at a titre of > 100 in 26/62 (42 percent) of rats tested, while in the second survey, 5/100 (5 percent) of rats had similar titres. In two surveys, conducted eight years apart, we confirmed that rats in Barbados are commonly infected with leptospira, and that viable organisms are found in the kidneys and urine, evidence of chronic infection and thus excretion of leptospira in rodent urine. Moreover, the predominant serovar isolated was copenhageni, of which Rattus spp. are the worldwide reservoirs. There was little evidence that rats act as a reservoir for the serovar bim, the most common cause of human leptospirosis in Barbados. (AU)