Duck hepatitis B virus can tolerate insertion, deletion, and partial frameshift mutation in the distal pre-S region.

In-frame and frameshift mutations were introduced into the pre-S region (1,212 base pairs) of duck hepatitis B virus. The in-frame mutants retained the inserted 12 nucleotides, while the frameshift mutants either reverted to wild type or exhibited a 10-nucleotide compensatory deletion downstream of the original mutation site. Thus, although duck hepatitis B virus has a compact and highly economical genome organization, it can replicate despite alterations of up to 9 amino acid codons in the pre-S and P open reading frames.     

Cloning of two adult hamster globin cDNAs (alpha and beta major).

A cDNA library was prepared from poly(A) mRNA extracted from adult anemic hamster spleen erythroid cells. cDNA clones containing inserts coding for adult alpha and beta major globin chains were isolated. Their identity was confirmed by (a) translation of hybrid selected mRNA and (b) nucleotide sequence analysis of the inserts and comparison to the adult globin cDNAs of mouse, rabbit and human. Availability of sequences for embryonic (Li et al. (1992) Biochim. Biophys. Acta 1130, 218-220) and adult globin cDNAs (this report) will aid in investigations of the molecular mechanisms involved in the globin ontogeny of hamsters.     

Ⅱ型限制性核酸内切酶NcrⅠ的研究

 在肉色诺卡氏菌C-212株Nocardia carnea C-212中筛选到一种Ⅱ型限制性核酸内切酶NcrⅠ,经与BglⅡ的λDNA降解物的酶谱比较,以及酶识别特异性和切割位点的检测,证明了NcrⅠ是已知的限制酶BglⅡ的同切限制酶,而且其切割位点也与BglⅡ相同,其为:     

15N resonance assignments of oxidized and reducedChromatium vinosum high-potential iron protein

The¹⁵N resonances in reduced and oxidizedChromatium vinosum high-potential iron protein have been assigned by use of¹H-¹H COSY spectra and¹H-¹⁵N HMQC, HMQC-COSY, and HMQC-NOESY spectra. Unambiguous assignment of 70 of 85 backbone¹⁵N resonances in the reduced protein and 62 of 85 resonances in the oxidized protein are made, as are 12 of 21 side-chain¹⁵N resonances.     

植物血细胞凝集素对小鼠脾脏淋巴细胞γ－谷氨酰基转肽酶活性的影响

本文就植物血细胞凝集素（ＰＨＡ）作用的不同时间对小鼠脾脏淋巴细胞γ－谷氨酰基转肽酶（γ－ＧＴ）活性的影响进行了观察。结果表明,脾脏淋巴细胞转化率随给予ＰＨＡ时间的延长而上升,对照组＜２４ｈ组＜４８ｈ组＜７２ｈ组;淋巴细胞γ－ＧＴ活性于２４ｈ明显强于对照组（Ｐ＜０．００１）,随着ＰＨＡ作用时间的延长其γ－ＧＴ活性逐渐下降,即４８ｈ组与对照组已无显著差异,而７２ｈ组却低于对照组（Ｐ＜０．００１）。可见ＰＨＡ在小鼠体内对γ－ＧＴ活性有很大影响。