Complete Genome Sequence of the Red-Pigmented Strain Serratia marcescens SCQ1 and Its Four Spontaneous Pigment Mutants

ABSTRACT Serratia marcescens SCQ1 is a red-pigmented bacterium isolated from silkworm larva with septicemia. Pigment-deficient spontaneous mutants arise when S. marcescens SCQ1 is incubated under relatively stable laboratory conditions for a long time. Here, we present the complete genome sequence of SCQ1 and the resequenced genomes of four spontaneous pigment mutants.

Dynamic Analysis of Nucleosides and Carbohydrates during Developmental Stages of Cordyceps militaris in Silkworm (Bombyxmori)

Background: Cultured Cordyceps militaris is very popular. Objective: To gain dynamic insight into activity markers in fruiting body of Cordyceps militaris (C. militaris) in Bombyxmori (B. mori), also named silkworm. Methods: The development stages of samples at 3, 9, 12, 19, 27, and 33 days after inoculation (DAI) were collected. HPLC coupled with diode array detection and evaporative light-scattering detection method (HPLC–DAD–ELSD) was used to determine eight makers, including six nucleosides and two carbohydrates from the samples. Results: C. militaris cultured 33 DAI with fifth star silkworm larva could accumulate higher levels of cordycepin (13.43 mg/g) than the highest reported cordycepin (8.57 g/L). The contents of cordycepin, adenosine, and trehalose were gradually increased with the formation of C. militaris fruiting bodies on silkworm larva, while mannitol was decreased. The change of guanosine was similar to uracil. Conclusions: Results suggested that mannitol could be accumulated in a short period during mycelium growth and could metabolize and transform into energy store and trehalose during fruit body formation. The inosine in the insect was completely utilized and transformed. The synergistic formation of cordycepin and adenosine or differences in metabolized pathways are a great possibility according to the same trend. Highlights: This research offered some reference to further find a certain regularity or metabolic mechanism.

Management of Climatic Factors for Successful Silkworm (Bombyx moriL.) Crop and Higher Silk Production: A Review

The seasonal differences in the environmental components considerably affect the genotypic expression in the form of phenotypic output of silkworm crop such as cocoon weight, shell weight, and cocoon shell ratio. The variations in the environmental conditions day to day and season to season emphasize the need of management of temperature and relative humidity for sustainable cocoon production. The present review paper discuss in details about the role of temperature and humidity on growth and development of silkworm including recent studies on heat shock protein. Study also discusses the influence of air and light on silkworm development. In addition to this study emphasis on the role of various environmental factors on embryonic development of silkworm egg, nutritional indices of silkworm larva and reproductive potential of silkworm moth. The study also highlights about the care to be required during silkworm spinning and influence of temperature and humidity on post cocoon parameters of silkworm. The study included future strategies to be taken for the management climatic condition for successful cocoon crop. The paper covers 140 references connected with the topic.