doc['halflives'] = [{'halflife': doc['half_life'], 'std': doc['half_life_std'], 'std_over_avg': doc['std_over_avg'],
                                'unit': 's', 'reference': [{'doi': '10.1186/s12864-016-3219-8'}], 'growth_medium': growth_medium,
                                'ordered_locus_name': doc['gene_fragment'], 'ar_cog': doc['ar_cog'], 'cog_class': doc['cog_class'],
                                'cog': doc['cog'], 'species': 'Methanosarcina acetivorans', 'ncbi_taxonomy_id': 188937}]