Response time characteristics of a transmissive uniformly doped GaAsP photocathode.

In this paper, the matrix difference method is used to calculate the photoelectron continuity equation and the outgoing electron flux density equation. The effects of the GaAsP/AlGaAsP recombination rate, electron diffusion coefficient, and activation layer thickness on the time-resolved characteristics and quantum efficiency of a GaAsP photocathode are systematically studied, and the accuracy of the theoretical calculation is verified by experiments. The response speed and quantum efficiency of the GaAsP photocathode can be greatly improved by adjusting the thickness of the GaAsP activation layer reasonably.

The Composition of Fungal Communities in the Rumen of Gayals (Bos frontalis), Yaks (Bos grunniens), and Yunnan and Tibetan Yellow Cattle (Bos taurs).

The rumen is a microbial-rich ecosystem in which rumen fungi play an important role in the feed digestion of ruminants. The composition of rumen fungi in free-range ruminants such as gayals, yaks, Tibetan yellow cattle, and the domesticated Yunnan yellow cattle was investigated by sequencing an internal transcribed spacer region 1 (ITS1) using Illumina MiSeq. A total of 285 092 optimized sequences and 904 operational taxonomic units (OTUs) were obtained from the four cattle breeds. The rumen fungi abundance and Chao and Simpson indexes were all higher in free-range ruminants than in domesticated ruminants. Three fungal phyla were identified by sequence comparison: Neocallimastigomycota, Basidiomycota, and Ascomycota. Basidiomycota and Ascomycota have very low abundance in the rumen of four breeds cattle but anaerobic fungi (AF) Neocallimastigomycota occurred in a high abundance. In Neocallimastigomycota, the dominant genera were Piromyces, Anaeromyces, Cyllamyces, Neocallimastix, and Orpionmyces in four cattle breeds. The composition of the major genera of Neocallimastigaceae varied greatly among the four cattle breeds. The unclassified genera were unequally distributed in gayals, yaks, Tibetan and Yunnan yellow cattle, accounting for 90.63%, 98.52%, 97.79%, and 27.01% respectively. It appears that free-range ruminants have more unknown rumen fungi than domesticated ruminants and the cattle breeds and animal diets had an impact on the diversity of rumen fungi.The rumen is a microbial-rich ecosystem in which rumen fungi play an important role in the feed digestion of ruminants. The composition of rumen fungi in free-range ruminants such as gayals, yaks, Tibetan yellow cattle, and the domesticated Yunnan yellow cattle was investigated by sequencing an internal transcribed spacer region 1 (ITS1) using Illumina MiSeq. A total of 285 092 optimized sequences and 904 operational taxonomic units (OTUs) were obtained from the four cattle breeds. The rumen fungi abundance and Chao and Simpson indexes were all higher in free-range ruminants than in domesticated ruminants. Three fungal phyla were identified by sequence comparison: Neocallimastigomycota, Basidiomycota, and Ascomycota. Basidiomycota and Ascomycota have very low abundance in the rumen of four breeds cattle but anaerobic fungi (AF) Neocallimastigomycota occurred in a high abundance. In Neocallimastigomycota, the dominant genera were Piromyces, Anaeromyces, Cyllamyces, Neocallimastix, and Orpionmyces in four cattle breeds. The composition of the major genera of Neocallimastigaceae varied greatly among the four cattle breeds. The unclassified genera were unequally distributed in gayals, yaks, Tibetan and Yunnan yellow cattle, accounting for 90.63%, 98.52%, 97.79%, and 27.01% respectively. It appears that free-range ruminants have more unknown rumen fungi than domesticated ruminants and the cattle breeds and animal diets had an impact on the diversity of rumen fungi.

Gene cloning and expression of fungal lignocellulolytic enzymes from the rumen of gayal (Bos frontalis).

A total of 6,219 positive clones were obtained by constructing a BAC library of uncultured ruminal fungi of gayal, and two clones (xynF1 and eglF2) with lignocellulolytic enzyme activity were selected. The sequencing results showed that xynF1 and eglF2 had 903-bp, and 1,995-bp, open reading frames likely to encode ß-xylanase (XynF1) and ß-glucosidase (EglF2), respectively. The amino acid sequence of XynF1 had 99% coverage and 95% homology to the endo-ß-1,4-xylanase encoded by the cellulase gene of Orpinomyces sp. LT-3 (GenBank accession No. AEO51791.1). The amino acid sequence of EglF2 had 99% coverage and 93% homology to the ß-glucosidase encoded by the cellulase gene of Piromyces sp. E2 (GenBank accession No. CAC34952.1). Analysis using the SMART software showed that XynF1 contains a glycoside hydrolase family 11 functional module and a carbohydrate-binding module, while EglF2 contains a glycoside hydrolase family 1 functional module. XynF1 showed the highest relative enzymatic activity, up to 95%, at 45°C and pH 4.2, while EglF2 showed the highest relative enzymatic activity, up to 95%, at 55°C and pH 6.2. In this study, we achieved efficient expression of the xynF1 and eglF2 genes in Pichia pastoris, which laid a foundation for the practical application of the lignocellulolytic enzymes.