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Hybrid larch is an excellent afforestation species in northern China. The instability of seed yield is an urgent problem to be solved. The biological characteristics related to seed setting in larch are different from those in angiosperms and other gymnosperms. Studying the developmental mechanism of the larch sporophyll can deepen our understanding of conifer reproductive development and help to ensure an adequate supply of seeds in the seed orchard. The results showed that the formation of microstrobilus primordia in hybrid larch could be observed in anatomical sections collected in the middle of July. The contents of endogenous gibberellin 3 (GA3) and abscisic acid (ABA) were higher and the contents of GA4, GA7, jasmonic acid and salicylic acid were lower in multiseeded larch. Transcriptome analysis showed that transcription factors were significantly enriched in the AP2 family. There were 23 differentially expressed genes in the buds of the multiseeded and less-seeded types, and the expression of most of these genes was higher in the buds than in the needles. We conclude that mid-July is the early stage of reproductive organ development in hybrid larch and is suitable for the study of reproductive development. GA3 and ABA may be helpful for improving seed setting in larch, and 23 AP2/EREBP family genes are involved in the regulation of reproductive development in larch., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Enhancing the acid tolerance of the probiotic bacterial strain Lactobacillus acidophilus NCFM (L. acidophilus NCFM) is critical for improving its viability during transiting through gastrointestinal tract, which is the basis of eliciting beneficial effects as an intestinal probiotic. In this study, the role of trehalose and the glutamateγ-aminobutyric acid antiporter gene gadC in enhancing the acid tolerance of L. acidophilus NCFM was investigated. Trehalose at a concentration of 0.5% (w/v) was sufficient to significantly increase bacterial viability at pH 2.0, and trehalose of 2.0% can preserve more than 80% of bacterial viability both at pH 2.0 and 3.0. The inactivation of gadC gene in L. acidophilus NCFM significantly reduced bacterial viability at pH 2.0, and diminished the protective effect of trehalose against acid stress. In conclusion, exogeneous trehalose conferred L. acidophilus NCFM enhanced viability at extreme low pH values, an effect that appeared to depend on its endogenous glutamate-depenent acid resistance system.

The aims of present study are to estimate the biological risks to the immunity of mice exposed to heavy ion radiation and to investigate the effect of N-acetylcysteine (NAC) on (12)C(6+) ion irradiation-induced lymphocyte DNA damage. Results showed that in the brine group, the levels of lymphocyte DNA damage and MN, thymocytes G(2)/M phase arrest and apoptosis percentages (except for activity of NK cells) were up at each time point. A time-response curve for MN and DNA damage appeared in the NAC group. We found that whole-body (12)C(6+) ion irradiation at a dose of 4 Gy could: induce lymphocyte DNA double-strand breaks (DSBs); immunocytes DSBs may lead to acute effects on immunity; and 200 mg/kg NAC showed significant protection against radiation harm.