Pathogenicity differences between South African isolates of Ornithobacterium rhinotracheale

Three selected South African Ornithobacterium rhinotrachealefield isolates were identified and inoculated via the caudal abdominal airsac into 28-day-old broilers, which were monitored under controlled laboratory conditions. It was concluded from data that the O. rhinotracheale isolates were capable of causing primary disease, with statistically significant resultant mass loss. Respiratory and arthritis symptoms were reproduced. However, no sinusitis was observed.\ud \ud Airsacculitis- and arthritis-lesion scoring techniques showed significant pathogenicity differences between isolates. Furthermore, differences in symptomatology were also seen between isolates. A highly significant reisolation of O. rhinotracheale was made from the brains of broilers challenged with isolate 2.\ud \ud In conclusion, the economic importance and financial loss due to Ornithobacterium rhinotracheale\ud infections in poultry were highlighted

ppGpp regulates the binding of two RNA polymerase molecules to the tyrT promoter

Bacterial promoters differ in the number of RNA polymerase molecules that bind to form a filterable polymerase-promoter complex. We show that two holoenzyme molecules interact with the tyrT promoter, probably as a dimer. This interaction is inhibited by ppGpp. By contrast a single holoenzyme monomer suffices for complex formation at the lacUV5 promoter. We propose that In vivo promoter selection by monomeric and dimeric forms of the enzyme could coordinate the synthesis of stable RNA with that of mRNA and could also account in part for the switch in transcriptional selectivity during the stringent response

RNA polymerase interactions with the upstream region of the E. coli tyrT promoter

Landasan tekhnologi menghasilkan sebuah keyakinan bahwa dengan menggunakan YouTube sebagai media pembelajaran dapat menjadi stimulus dalam proses peningkatan keterampilan berpikir kritis peserta didik. Penelitian ini digunakan untuk menjawab tiga masalah pokok, yaitu bagaimana efektifitas penggunaan video YouTube sebagai media pembelajaran untuk meningkatkan keterampilan berpikir kritis, bagaimana peningkatkan keterampilan berpikir kritis dalam pembelajaran Pendidikan Agama Islam, dan bagaimana penggunaan video YouTube sebagai media pembelajaran Pendidikan Agama Islam. Penelitian ini menggunakan metode campuran kuantitatif dan kualitatif. Penelitian ini menggunakan eksperimen nonequivalent control group design. Data diperoleh dengan melakukan tes, wawancara, observasi dan dokumentasi. Hasil penelitian ini menyimpulkan penggunaan YouTube video sebagai media pembelajaran Pendidikan Agama Islam dapat menambah wawasan, pembelajaran aktif, peserta didik mampu menganalisis permasalahan dan tidak malu bertanya. Dengan YouTube video peningkatan keterampilan berpikir kritis kelas ekperimen lebih tinggi dari pada kelas kontrol, berdasarkan uji independent sampel t-test diperoleh nilai sig 2 tailed < 0.05 sehingga Ho diterima dan Ha ditolak, penggunaan YouTube video sebagai media pembelajaran Pendidikan Agama Islam untuk meningkatkan keterampilan berpikir kritis dapat dikatakan efektif karena peserta didik dapat mencapai tujuan pembelajaran, aktif bertanya, mampu menganalisis permasalahan. Berdasarkan data kuantatif diperoleh nilai sig 2 tailed < 0.05. Dimana terdapat perbedaan rata-rata antara kelas eksperimen dan kelas kontrol