来自用户 小擎子 的文献。
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小擎子 (2024-03-31 23:16):
#paper doi:10.1021/acs.estlett.4c00081 Environ. Sci. Technol. Lett., 2024, Drinking Boiled Tap Water Reduces Human Intake of Nanoplastics and Microplastics。 如果担心水里有微塑料,可以先烧开水,再过滤再喝。硬水(每升水300mg CaCO3)去除微塑料效果较好(约去除90),软水(每升水CaCO3小于60mg)效果较差(去除约25%)。作者认为粒径越小,表面能越高,越倾向于团聚或者吸附在其他物质表面,来减少自身的表面能。硬水烧开的过程中,随着水温升高,CaCO3形成了包封塑料颗粒的水垢颗粒或晶体结构。
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小擎子 (2024-02-29 22:29):
#paper doi:10.1016/j.jhazmat.2020.122969 J Hazard Mater, 2022, Microplastics in take-out food containers。论文研究了中国五个城市常用的4种外卖的塑料包装(PP、PE、PS、PET)在不同情况下的微塑料释放情况。预实验发现,四种处理(直接冲洗、热水浸泡后冲洗、微波加热1分钟后冲洗、冷藏后冲洗6h)中PP容器的微塑料丰度没有显著差异。正式实验中,采用直接冲洗和热水浸泡后冲洗两种处理方法分别模拟从外卖容器中取食和外卖送餐过程(热水处理并摇晃),PET因为遇热会变形没有进行热水处理。PP、PE和PS三种材质在两种处理后,总微塑料丰度没有显著差异。通过扫描电镜观察,热水处理后,PP、PE和PS均有表层变化,PE(类似一般纸杯,纸上喷涂膜)观察到喷涂膜分离。因为一直担心外卖的塑料容器会不会增加微塑料摄入量,所以看了下这篇文献,实验过程较为严谨,包括中间对空气进行了把控,也进行了空白对照实验。不过我认为这篇论文的实验并没有看到不同处理导致更多剥离微塑料的结果,相反,各种处理观察到的微塑料丰度均差不多。其中微塑料含量丰度最高的PS材质(很久以前常见的发泡塑料饭盒),我查百度百科据说也是国家禁用了。当然作者怀疑热水处理导致材质表面的变化,虽然没有释放出更多微塑料,但也可能会释放出更多的添加剂。我认为比较意外的一点是,在显微观察微塑料时,认为材质和颜色与容器相同的是剥落微塑料,其他则不是,其他认为可能是空气来源微塑料(我理解虽然实验过程中没有引入,但是制作这些外卖容器中引入了)。这些空气来源微塑料占了总微塑料的含量的70%,包括聚酯、尼龙、腈纶和人造丝。作者认为通过外卖食品容器摄入微塑料,一个来源是容器本身,另一个是大气沉降。因为比较好奇热水、摇晃、微波和冷藏是否会导致更多的微塑料释放,看这篇文献,作者用PP容器实验,在微塑料丰度上看是没有影响的。除了PP容器外,其他三类(PET、PS、PE)都不适合微波或低温保存,但是我们日常生活中不一定能都按照规则使用这些材质。包括油是否对微塑料有富集,这篇文献也考虑了油的特殊性,但是只能未来做实验再看了(之前看文献报告橄榄油可以富集微塑料)。我比较担心一般纸杯装可乐的影响(常见的快餐饮料包装),这个只能之后再查查了。另外,微塑料污染被世卫组织列为第二大危机(第一是气候变化)。我观察到有些商家推出一些产品,比如排塑益生菌,据说可以排出百分之多少吃入的微塑料,我对此也比较怀疑(毕竟吃进去的大部分也会进入粪便、能否拦阻微塑料进入血液、拦阻能穿过血脑屏障的这些微塑料),需要再看实验和数据考证。
Abstract:
Microplastics have been detected in various media including water, sediment, and seafood, whereas there are few studies focusing on microplastics in take-out containers. In this study, we collected take-out containers … >>>
Microplastics have been detected in various media including water, sediment, and seafood, whereas there are few studies focusing on microplastics in take-out containers. In this study, we collected take-out containers made of common polymer materials (polypropylene, PP; polystyrene, PS; polyethylene, PE; polyethylene terephthalate, PET) from five cities in China. Microplastics in the containers were analyzed after different treatments (direct flushing and flushing after immersing with hot water). Our results showed that microplastics were found in all take-out containers and abundance ranged from 3 to 29 items/container. The highest abundance occurred in PS containers with rough surface. The polymer types of some detected particles were the same as those of original containers, accounting for 30% of the total microplastics; other types included polyester, rayon, acrylic, and nylon. Treating the containers with hot water did not influence microplastic abundance. Our study indicates that microplastics in take-out containers come from atmospheric fallout and flakes from container's inner surfaces. Under slight mechanical force, loose structure and rough surface of PS containers can flake off microplastics, entering water more easily. Based on the microplastic abundance in take-out containers, people who order take-out food 4-7 times weekly may ingest 12-203 pieces of microplastics through containers. <<<
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小擎子 (2023-08-31 23:40):
#paper doi:10.1158/2159-8290.CD-21-0324 Cancer Discov,2022, The Cancer Microbiome: Recent Highlights and Knowledge Gaps 癌症微生物组 最近的亮点和知识空白。提出了微生物影响癌症进程的几种模型,微生物参与肿瘤发生的几种理论,网罗了各种癌症与微生物关系的相关报道。癌症微生物可能会帮助未来的早期癌症诊断。有一个比较有意思的,奈瑟属酒精脱氢酶发达,乳酸杆菌RA 可以将乙醛代谢为无毒模式。饮酒会引起奈瑟属升高,乳酸杆菌RA减少。但是口腔鳞癌(与酒精损伤有关)里没有观察到这个现象,文献观点认为这是早期微生物因素驱动或者影响了口腔鳞癌的发展,但后期检测不到,属于机制中的肇事逃逸模型。
IF:29.700Q1 Cancer discovery, 2021-10. DOI: 10.1158/2159-8290.CD-21-0324 PMID: 34400408
Abstract:
Knowledge of the human microbiome, which is likely a critical factor in the initiation, progression, and prognosis of multiple forms of cancer, is rapidly expanding. In this review, we focus … >>>
Knowledge of the human microbiome, which is likely a critical factor in the initiation, progression, and prognosis of multiple forms of cancer, is rapidly expanding. In this review, we focus on recent investigations to discern putative, causative microbial species and the microbiome composition and structure currently associated with procarcinogenesis and tumorigenesis at select body sites. We specifically highlight forms of cancer, gastrointestinal and nongastrointestinal, that have significant bacterial associations and well-defined experimental evidence with the aim of generating directions for future experimental and translational investigations to develop a clearer understanding of the multifaceted mechanisms by which microbiota affect cancer formation. SIGNIFICANCE: Emerging and, for some cancers, strong experimental and translational data support the contribution of the microbiome to cancer biology and disease progression. Disrupting microbiome features and pathways contributing to cancer may provide new approaches to improving cancer outcomes in patients. <<<
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4.
小擎子 (2023-07-31 23:35):
#paper doi:10.1038/s41467-023-38347-2 Nat Commun, 2023, A general model to predict small molecule substrates of enzymes based on machine and deep learning, 基于机器学习和深度学习的酶小分子底物预测通用模型。可以预测任意1种酶和大约1400种小分子是否为其底物的通用模型。帮助减少确定特定酶的底物分子的筛选范围,帮助降低实验成本。缺点是目前有5%的假阳性率,因此比较适合预测单一酶的候选底物,不适合预测基因组规模代谢模型中的所有酶的候选底物。
IF:14.700Q1 Nature communications, 2023-05-15. DOI: 10.1038/s41467-023-38347-2 PMID: 37188731
Abstract:
For most proteins annotated as enzymes, it is unknown which primary and/or secondary reactions they catalyze. Experimental characterizations of potential substrates are time-consuming and costly. Machine learning predictions could provide … >>>
For most proteins annotated as enzymes, it is unknown which primary and/or secondary reactions they catalyze. Experimental characterizations of potential substrates are time-consuming and costly. Machine learning predictions could provide an efficient alternative, but are hampered by a lack of information regarding enzyme non-substrates, as available training data comprises mainly positive examples. Here, we present ESP, a general machine-learning model for the prediction of enzyme-substrate pairs with an accuracy of over 91% on independent and diverse test data. ESP can be applied successfully across widely different enzymes and a broad range of metabolites included in the training data, outperforming models designed for individual, well-studied enzyme families. ESP represents enzymes through a modified transformer model, and is trained on data augmented with randomly sampled small molecules assigned as non-substrates. By facilitating easy in silico testing of potential substrates, the ESP web server may support both basic and applied science. <<<
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小擎子 (2023-06-30 23:20):
#paper doi:10.1126/science.aba6527 Science, 2020, Designed protein logic to target cells with precise combinations of surface antigens 设计蛋白质逻辑,以靶向具有表面抗原精确组合的细胞。文献从头设计了协同定位依赖性蛋白质开关(Co-LOCKR),可执行“AND”、“OR”和“NOT”布尔逻辑运算。只有当满足所有条件时,这些开关才会通过构象变化激活,实现在复杂细胞群中以单细胞分辨率产生快速的、转录依赖的反应。使用“AND”门来重定向T细胞对表达两种表面抗原的肿瘤细胞的特异性,同时避免对单抗原细胞的脱靶识别,以及添加“NOT”或“OR”以避免或包括表达第三抗原的细胞。文章涉及蛋白质设计知识太多了,有点看不懂,但是这个设计是很有想象力很有意思的,可以实现只在特定细胞的细胞膜附近反应的效果。蛋白质设计的门槛现在降得很低,但就像David Baker说的,关键是你想设计什么样的蛋白。
Abstract:
Precise cell targeting is challenging because most mammalian cell types lack a single surface marker that distinguishes them from other cells. A solution would be to target cells using specific … >>>
Precise cell targeting is challenging because most mammalian cell types lack a single surface marker that distinguishes them from other cells. A solution would be to target cells using specific combinations of proteins present on their surfaces. In this study, we design colocalization-dependent protein switches (Co-LOCKR) that perform AND, OR, and NOT Boolean logic operations. These switches activate through a conformational change only when all conditions are met, generating rapid, transcription-independent responses at single-cell resolution within complex cell populations. We implement AND gates to redirect T cell specificity against tumor cells expressing two surface antigens while avoiding off-target recognition of single-antigen cells, and three-input switches that add NOT or OR logic to avoid or include cells expressing a third antigen. Thus, de novo designed proteins can perform computations on the surface of cells, integrating multiple distinct binding interactions into a single output. <<<
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小擎子 (2023-05-31 23:05):
#paper 10.1126/science.1257481 Science, 2014 , High thermodynamic stability of parametrically designed helical bundles 参数化设计的螺旋束的高热力学稳定性。通过参数化骨架生成与Rosetta蛋白质设计相结合的方法,生成非常稳定的蛋白质结构。不依赖已知序列基序的情况下轻松生成具有精细几何形状的超稳定蛋白质,有助于基于蛋白质的纳米结构、疗法和催化剂的设计。核心是参数化设计,依靠的是对Crick Coiled-coil方程做参数扰动。0.1埃的扰动可以生成成千上万个α螺旋设计骨架。文章找了几种低能量的设计做测试,实验验证,晶体结构与设计一致,且稳定性超好,堪称“砖头”。ps 因文章较早,用的是Rosetta设计序列,如果改用ProteinMPNN,可以生成有更多活性表达的蛋白质序列。
Abstract:
We describe a procedure for designing proteins with backbones produced by varying the parameters in the Crick coiled coil-generating equations. Combinatorial design calculations identify low-energy sequences for alternative helix supercoil … >>>
We describe a procedure for designing proteins with backbones produced by varying the parameters in the Crick coiled coil-generating equations. Combinatorial design calculations identify low-energy sequences for alternative helix supercoil arrangements, and the helices in the lowest-energy arrangements are connected by loop building. We design an antiparallel monomeric untwisted three-helix bundle with 80-residue helices, an antiparallel monomeric right-handed four-helix bundle, and a pentameric parallel left-handed five-helix bundle. The designed proteins are extremely stable (extrapolated ΔGfold > 60 kilocalories per mole), and their crystal structures are close to those of the design models with nearly identical core packing between the helices. The approach enables the custom design of hyperstable proteins with fine-tuned geometries for a wide range of applications. <<<
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小擎子 (2023-04-30 23:14):
#paper doi: 10.1038/s41592-021-01141-3 Nat Methods, 2021, Challenges in Benchmarking Metagenomic Profilers. 文献提出了一个研究宏基因组中会遇到的问题,即计算相对丰度时,不同生信工具给出的统计结果不同。区别就是有的结果是给出的序列丰度(DNA to DNA),有的结果给出的是物种丰度(DNA to Marker)。序列丰度和物种丰度的差别在于,有没有将物种的基因组大小考虑在其中。序列丰度是不考虑物种基因组大小的(如Kraken)。文章认为,基于物种丰度(即考虑物种基因组大小)的结果更具有解释性,建议严谨解释宏基因组分析结果,特别是从序列丰度得出的结果。
IF:36.100Q1 Nature methods, 2021-06. DOI: 10.1038/s41592-021-01141-3 PMID: 33986544
Abstract:
Accurate microbial identification and abundance estimation are crucial for metagenomics analysis. Various methods for classification of metagenomic data and estimation of taxonomic profiles, broadly referred to as metagenomic profilers, have … >>>
Accurate microbial identification and abundance estimation are crucial for metagenomics analysis. Various methods for classification of metagenomic data and estimation of taxonomic profiles, broadly referred to as metagenomic profilers, have been developed. Nevertheless, benchmarking of metagenomic profilers remains challenging because some tools are designed to report relative sequence abundance while others report relative taxonomic abundance. Here we show how misleading conclusions can be drawn by neglecting this distinction between relative abundance types when benchmarking metagenomic profilers. Moreover, we show compelling evidence that interchanging sequence abundance and taxonomic abundance will influence both per-sample summary statistics and cross-sample comparisons. We suggest that the microbiome research community pay attention to potentially misleading biological conclusions arising from this issue when benchmarking metagenomic profilers, by carefully considering the type of abundance data that were analyzed and interpreted and clearly stating the strategy used for metagenomic profiling. <<<
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8.
小擎子 (2023-03-31 23:05):
#paper doi:10.1136/gutjnl-2018-317178 Gut, 2019, Enteric fungal microbiota dysbiosis and ecological alterations in colorectal cancer 结直肠癌的肠道真菌失调和生态改变。一般研究癌症里的微生物多是细菌,病毒和真菌的少。这篇文献主要分析了结直肠癌患者样本的真菌。真菌一般在采样中的序列占比也少,但仍有分析价值。研究分析了香港的184名CRC患者、197名腺瘤患者和204名对照受试者。分析的粪便样本,分为发现队列和验证队列。主成分分析显示结直肠癌和对照组可以分为两个簇,早期和晚期的结直肠癌也有不同的真菌群。与健康人相比,结直肠癌患者粪便内的担子菌(Basidiomycota):子囊菌(Ascomycota)的比值增加。在CRC中真菌纲马拉色纲(Malasseziomycetes)富集,Saccharomycetes和Pneumocystidomycetes减少。研究找了14种真菌标志物其丰度可以将CRC和对照组分开,AUC为0.74~0.93。研究还采用了SparCC算法做了生态学分析,与对照组相比,CRC中的真菌会有界内共存的联系,而真菌与细菌会有排斥现象。研究发现了真菌粪便标志物在诊断CRC上有潜在潜力。真菌一般分析较少,研究主要用了Kraken注释reads,并且用Jellyfish程序利用公开数据做了一个自定义数据库。
IF:23.000Q1 Gut, 2019-04. DOI: 10.1136/gutjnl-2018-317178 PMID: 30472682
Abstract:
OBJECTIVES: Bacteriome and virome alterations are associated with colorectal cancer (CRC). Nevertheless, the gut fungal microbiota in CRC remains largely unexplored. We aimed to characterise enteric mycobiome in CRC.DESIGN: Faecal … >>>
OBJECTIVES: Bacteriome and virome alterations are associated with colorectal cancer (CRC). Nevertheless, the gut fungal microbiota in CRC remains largely unexplored. We aimed to characterise enteric mycobiome in CRC.DESIGN: Faecal shotgun metagenomic sequences of 184 patients with CRC, 197 patients with adenoma and 204 control subjects from Hong Kong were analysed (discovery cohort: 73 patients with CRC and 92 control subjects; validation cohort: 111 patients with CRC, 197 patients with adenoma and 112 controls from Hong Kong). CRC-associated fungal markers and ecological changes were also validated in additional independent cohorts of 90 patients with CRC, 42 patients with adenoma and 66 control subjects of published repository sequences from Germany and France. Assignment of taxonomies was performed by exact k-mer alignment against an integrated microbial reference genome database.RESULTS: Principal component analysis revealed separate clusters for CRC and control (p<0.0001), with distinct mycobiomes in early-stage and late-stage CRC (p=0.0048). Basidiomycota:Ascomycota ratio was higher in CRC (p=0.0042), with increase in Malasseziomycetes (p<0.0001) and decrease in Saccharomycetes (p<0.0001) and Pneumocystidomycetes (p=0.0017). Abundances of 14 fungal biomarkers distinguished CRC from controls with an area under the receiver-operating characteristic curve (AUC) of 0.93 and validated AUCs of 0.82 and 0.74 in independent Chinese cohort V1 and European cohort V2, respectively. Further ecological analysis revealed higher numbers of co-occurring fungal intrakingdom and co-exclusive bacterial-fungal correlations in CRC (p<0.0001). Moreover, co-occurrence interactions between fungi and bacteria, mostly contributed by fungal Ascomycota and bacterial Proteobacteria in control, were reverted to co-exclusive interplay in CRC (p=0.00045).CONCLUSIONS: This study revealed CRC-associated mycobiome dysbiosis characterised by altered fungal composition and ecology, signifying that the gut mycobiome might play a role in CRC. <<<
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小擎子 (2023-02-28 23:59):
#paper  The cancer chemotherapeutic 5-fluorouracil is a potent Fusobacterium nucleatum inhibitor and its activity is modified by intratumoral microbiota. Cell Rep. 2022 Nov 15;41(7):111625. doi: 10.1016/j.celrep.2022.111625. PMID: 36384132.文章发现结直肠癌里的肿瘤微生物群可以对一线CRC化疗药物5-氟尿嘧啶进行修饰,降低药物的功效。5-氟尿嘧啶既是对结直肠癌上皮细胞有毒性的,也是靶向结肠癌中的核梭杆菌Fn(与癌症进展和复发正相关)的。而肿瘤微生物群修饰5-氟尿嘧啶后,可以减轻对Fn和CRC上皮细胞的毒性。其中结直肠癌肿瘤微生物群里的大肠杆菌在修饰5-氟尿嘧啶的作用得到了证实。文章也用了随机森林对宏基因组数据进行了特征分类,大肠杆菌是5-FU暴露后“修饰者”组的分类,总体而言,具有最高的平均下降精度值,支持大肠杆菌作为模型中分类器的重要性。
IF:7.500Q1 Cell reports, 2022-11-15. DOI: 10.1016/j.celrep.2022.111625 PMID: 36384132
Abstract:
Fusobacterium nucleatum (Fn) is a dominant bacterial species in colorectal cancer (CRC) tissue that is associated with cancer progression and poorer patient prognosis. Following a small-molecule inhibitor screen of 1,846 … >>>
Fusobacterium nucleatum (Fn) is a dominant bacterial species in colorectal cancer (CRC) tissue that is associated with cancer progression and poorer patient prognosis. Following a small-molecule inhibitor screen of 1,846 bioactive compounds against a Fn CRC isolate, we find that 15% of inhibitors are antineoplastic agents including fluoropyrimidines. Validation of these findings reveals that 5-fluorouracil (5-FU), a first-line CRC chemotherapeutic, is a potent inhibitor of Fn CRC isolates. We also identify members of the intratumoral microbiota, including Escherichia coli, that are resistant to 5-FU. Further, CRC E. coli isolates can modify 5-FU and relieve 5-FU toxicity toward otherwise-sensitive Fn and human CRC epithelial cells. Lastly, we demonstrate that ex vivo patient CRC tumor microbiota undergo community disruption after 5-FU exposure and have the potential to deplete 5-FU levels, reducing local drug efficacy. Together, these observations argue for further investigation into the role of the CRC intratumoral microbiota in patient response to chemotherapy. <<<
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小擎子 (2023-01-31 23:12):
#paper doi:10.1038/s41467-022-35237-x Nat Commun., 2022, Sourcing thermotolerant poly(ethylene terephthalate) hydrolase scaffolds from natural diversity。将HMM方法与机器学习相结合,以鉴定PET水解酶,根据序列预测酶的最佳活性温度。从公开数据库获得序列和环境最佳生长温度(OGT),只保留OGT大于50℃的序列,对于没有OGT信息的序列,使用计算氨基酸特征的支持向量机方法训练机器学习模型(ThermoProt)来区分来自嗜热菌大于50℃的8000种蛋白和来自非嗜热菌的小于50℃的8000种蛋白。ThremProt表现出86.6%的准确率。选择了74种假定的耐热PET水解酶进行实验筛选。实验筛选出了23种热稳定酶,均未被报道,并且超过先前报道的36种酶的PET水解酶活性。
IF:14.700Q1 Nature communications, 2022-12-21. DOI: 10.1038/s41467-022-35237-x PMID: 36543766
Abstract:
Enzymatic deconstruction of poly(ethylene terephthalate) (PET) is under intense investigation, given the ability of hydrolase enzymes to depolymerize PET to its constituent monomers near the polymer glass transition temperature. To … >>>
Enzymatic deconstruction of poly(ethylene terephthalate) (PET) is under intense investigation, given the ability of hydrolase enzymes to depolymerize PET to its constituent monomers near the polymer glass transition temperature. To date, reported PET hydrolases have been sourced from a relatively narrow sequence space. Here, we identify additional PET-active biocatalysts from natural diversity by using bioinformatics and machine learning to mine 74 putative thermotolerant PET hydrolases. We successfully express, purify, and assay 51 enzymes from seven distinct phylogenetic groups; observing PET hydrolysis activity on amorphous PET film from 37 enzymes in reactions spanning pH from 4.5-9.0 and temperatures from 30-70 °C. We conduct PET hydrolysis time-course reactions with the best-performing enzymes, where we observe differences in substrate selectivity as function of PET morphology. We employed X-ray crystallography and AlphaFold to examine the enzyme architectures of all 74 candidates, revealing protein folds and accessory domains not previously associated with PET deconstruction. Overall, this study expands the number and diversity of thermotolerant scaffolds for enzymatic PET deconstruction. <<<
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11.
小擎子 (2022-12-31 22:08):
#paper doi: 10.1016/j.xgen.2022.100179. Cell Genom, 2022, Uncovering novel mutational signatures by de novo extraction with SigProfilerExtractor。COSMIC网站推荐的检测肿瘤特征的工具,文献主推SigProfilerExtractor,也测试了另外13种检测肿瘤特征的工具。文献做了广泛的数据模拟,添加不同的噪声干扰,比较不同工具的算法表现,做了肿瘤特征提取较为可靠的benchmarking。
IF:11.100Q1 Cell genomics, 2022-Nov-09. DOI: 10.1016/j.xgen.2022.100179 PMID: 36388765
Abstract:
Mutational signature analysis is commonly performed in cancer genomic studies. Here, we present SigProfilerExtractor, an automated tool for extraction of mutational signatures, and benchmark it against another 13 bioinformatics tools … >>>
Mutational signature analysis is commonly performed in cancer genomic studies. Here, we present SigProfilerExtractor, an automated tool for extraction of mutational signatures, and benchmark it against another 13 bioinformatics tools by using 34 scenarios encompassing 2,500 simulated signatures found in 60,000 synthetic genomes and 20,000 synthetic exomes. For simulations with 5% noise, reflecting high-quality datasets, SigProfilerExtractor outperforms other approaches by elucidating between 20% and 50% more true-positive signatures while yielding 5-fold less false-positive signatures. Applying SigProfilerExtractor to 4,643 whole-genome- and 19,184 whole-exome-sequenced cancers reveals four novel signatures. Two of the signatures are confirmed in independent cohorts, and one of these signatures is associated with tobacco smoking. In summary, this report provides a reference tool for analysis of mutational signatures, a comprehensive benchmarking of bioinformatics tools for extracting signatures, and several novel mutational signatures, including one putatively attributed to direct tobacco smoking mutagenesis in bladder tissues. <<<
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12.
小擎子 (2022-11-30 23:57):
# paper doi:10.1186/s13059-016-0997-x;Genome Biol.2016 Mash: fast genome and metagenome distance estimation using MinHash, Mash工具,用MinHash快速衡量基因组和宏基因组距离。Mash主要实现sketch和dist两个功能,sketch将序列或者序列合集转换为MinHash sketch,可以大幅缩小内存占用,dist计算Jaccard index可以在可控误差范围内近似ANI,且计算效率大大提供。重点是k-mer和s(sketch的size大小)的选择,会影响误差。Mash的特点是计算消耗主要是生成sketch上,sketch一旦生成,上万基因组的相似性比较和聚类几乎是瞬时完成的。
IF:10.100Q1 Genome biology, 2016-06-20. DOI: 10.1186/s13059-016-0997-x PMID: 27323842
Abstract:
Mash extends the MinHash dimensionality-reduction technique to include a pairwise mutation distance and P value significance test, enabling the efficient clustering and search of massive sequence collections. Mash reduces large … >>>
Mash extends the MinHash dimensionality-reduction technique to include a pairwise mutation distance and P value significance test, enabling the efficient clustering and search of massive sequence collections. Mash reduces large sequences and sequence sets to small, representative sketches, from which global mutation distances can be rapidly estimated. We demonstrate several use cases, including the clustering of all 54,118 NCBI RefSeq genomes in 33 CPU h; real-time database search using assembled or unassembled Illumina, Pacific Biosciences, and Oxford Nanopore data; and the scalable clustering of hundreds of metagenomic samples by composition. Mash is freely released under a BSD license ( https://github.com/marbl/mash ). <<<
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13.
小擎子 (2022-10-31 23:59):
#paper doi:10.1126/science.aao3290 Science, 2019, The commensal microbiome is associated with anti-PD-1 efficacy in metastatic melanoma patients. 共生微生物组与转移性黑色素瘤患者的抗PD-1疗效相关,对免疫治疗有反应为R组,无反应为NR组。 文章开始用了16S测序、宏基因组测序和定量PCR,后比较发现,宏基因组的数据在R与NR的差异代表物种较少且与16S重叠(比较奇怪),后选用16S测序来做分析。在R组中,细菌物种, Bifidobacterium longum(长双歧杆菌), Collinsella aerofaciens(科林塞拉菌)和 Enterococcus faecium(屎肠球菌)含量较高,通过无菌小鼠实验,确认来自R组的粪便可以改善肿瘤控制,增强T细胞反应,提供抗PD-L1治疗的疗效。文献结尾的话,“除了微生物组之外,其他肿瘤和宿主因素会影响抗肿瘤免疫和癌症免疫治疗的疗效。Wnt/β-连环蛋白通路的肿瘤内在激活和Pte的缺失或突变已被证明会导致 T细胞浸润不足进入肿瘤微环境和对检查点阻断免疫疗法的耐药性。免疫调节基因中的种系多态性也有可能影响自发抗肿瘤T细胞反应的程度。我们在这里描述的结果开辟了将共生微生物组成以及肿瘤基因组学和种系遗传学整合到多参数模型中的途径,该模型可以最大限度地提高预测哪些患者可能对抗PD-1等免疫疗法产生反应的能力。”
Abstract:
Anti-PD-1-based immunotherapy has had a major impact on cancer treatment but has only benefited a subset of patients. Among the variables that could contribute to interpatient heterogeneity is differential composition … >>>
Anti-PD-1-based immunotherapy has had a major impact on cancer treatment but has only benefited a subset of patients. Among the variables that could contribute to interpatient heterogeneity is differential composition of the patients' microbiome, which has been shown to affect antitumor immunity and immunotherapy efficacy in preclinical mouse models. We analyzed baseline stool samples from metastatic melanoma patients before immunotherapy treatment, through an integration of 16 ribosomal RNA gene sequencing, metagenomic shotgun sequencing, and quantitative polymerase chain reaction for selected bacteria. A significant association was observed between commensal microbial composition and clinical response. Bacterial species more abundant in responders included , , and Reconstitution of germ-free mice with fecal material from responding patients could lead to improved tumor control, augmented T cell responses, and greater efficacy of anti-PD-L1 therapy. Our results suggest that the commensal microbiome may have a mechanistic impact on antitumor immunity in human cancer patients. <<<
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小擎子 (2022-09-30 23:54):
#paper doi:10.1016/j.cell.2022.09.005 Cell, 2022, Pan-cancer analyses reveal cancer-type-specific fungal ecologies and bacteriome interactions。新鲜出炉的首个泛癌症真菌生物组图谱。35种癌症,17401个样本(组织,血液,血浆)。文章发现,细菌在肿瘤微生物组中优于真菌.但宏基因组的生物信息学分析,确实可以支持样本里真菌的存在。文章也用染色体显色的方法在癌组织中可视化了人类肿瘤里的真菌,并发现真菌会有癌症类型特异性的定位模式。真菌染色主要在胰腺癌,乳腺癌和卵巢癌中存在,但是大部分都定位在黑色素瘤和肺癌里的巨噬细胞。文献还使用了无监督分类揭示真菌共生驱动的真菌-细菌-免疫簇.这种免疫簇可以区分免疫反应亚型。
IF:45.500Q1 Cell, 2022-09-29. DOI: 10.1016/j.cell.2022.09.005 PMID: 36179670
Abstract:
Cancer-microbe associations have been explored for centuries, but cancer-associated fungi have rarely been examined. Here, we comprehensively characterize the cancer mycobiome within 17,401 patient tissue, blood, and plasma samples across … >>>
Cancer-microbe associations have been explored for centuries, but cancer-associated fungi have rarely been examined. Here, we comprehensively characterize the cancer mycobiome within 17,401 patient tissue, blood, and plasma samples across 35 cancer types in four independent cohorts. We report fungal DNA and cells at low abundances across many major human cancers, with differences in community compositions that differ among cancer types, even when accounting for technical background. Fungal histological staining of tissue microarrays supported intratumoral presence and frequent spatial association with cancer cells and macrophages. Comparing intratumoral fungal communities with matched bacteriomes and immunomes revealed co-occurring bi-domain ecologies, often with permissive, rather than competitive, microenvironments and distinct immune responses. Clinically focused assessments suggested prognostic and diagnostic capacities of the tissue and plasma mycobiomes, even in stage I cancers, and synergistic predictive performance with bacteriomes. <<<
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小擎子 (2022-08-31 23:41):
#paper doi: 10.1126/science.aaw7479 Nature, 2022, Akkermansia muciniphila phospholipid induces homeostatic immune responses. 找到了明星益生菌Akk调节免疫的物质a15:0-i15:0 PE,解释了其作用机制。a15:0-i15:0 PE是Akk菌膜脂质的主要成分之一。Akk菌隶属于疣微菌门(Verrucomicrobia),是肠道微生物中唯一一个来自疣微菌门的细菌。大海捞针式的研究,对什么样的生长环境能使Akk菌产生a15:0-i15:0 PE比较好奇。
Abstract:
Intestinal adaptive immune responses influence host health, yet only a few intestinal bacteria species that induce cognate adaptive immune responses during homeostasis have been identified. Here, we show that , … >>>
Intestinal adaptive immune responses influence host health, yet only a few intestinal bacteria species that induce cognate adaptive immune responses during homeostasis have been identified. Here, we show that , an intestinal bacterium associated with systemic effects on host metabolism and PD-1 checkpoint immunotherapy, induces immunoglobulin G1 (IgG1) antibodies and antigen-specific T cell responses in mice. Unlike previously characterized mucosal responses, T cell responses to are limited to T follicular helper cells in a gnotobiotic setting, without appreciable induction of other T helper fates or migration to the lamina propria. However, -specific responses are context dependent and adopt other fates in conventional mice. These findings suggest that, during homeostasis, contextual signals influence T cell responses to the microbiota and modulate host immune function. <<<
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小擎子 (2022-07-31 23:38):
#paper doi:10.1242/dmm.000976 Dis Model Mech , 2008, Mouse xenograft models vs GEM models for human cancer therapeutics. 找到比较早的一篇在人类癌症治疗中的小鼠异种移植模型和小鼠基因编辑的文章。感觉文章只是泛泛而谈,并不是自己做实验。一般小鼠模型有3种。1)把人类的肿瘤细胞注射或者肿瘤移植到无胸腺裸鼠或者严重免疫缺陷小鼠 2)人源化小鼠, 异种移植使用通过注射外周血或骨髓细胞“人源化”的NOD/SCID小鼠,为了重建对肿瘤的免疫反应3)基因工程小鼠模型(简称GEM)前两种都算异种移植模型,文献的观点是,一般异种移植模型通常被认为不如GEM模型,但是作者觉得每种模型在癌症诊断和临床前治疗方式都有其用途。我这里简单翻译一下文献中的作者观点,第一种把癌细胞注射或者癌组织移植到无胸腺裸鼠/免疫缺陷小鼠,优点有三,1)可以预测人类患者肿瘤对药物反应,2)提供真实的肿瘤细胞异质性 3)允许快速分析人类肿瘤对治疗方案的反应;缺点是小鼠是免疫受损的,肿瘤微环境就不那么真实了。第二种,人源化小鼠的异种移植模型,优点有三,1)可以部分模拟人的肿瘤微环境 2)预测人类患者肿瘤的药物反应 3)提供了真实的肿瘤细胞异质性;缺点有二,1)贵,2)技术复杂。第三种,基因工程小鼠(GEM),优点有四,1)通过使用多种种系小鼠,可以做很多基因背景的潜在研究 2)肿瘤是在一个完整的免疫系统中(真实的微环境)3)可以模拟人类肿瘤中鉴定的明确的突变 4)可以从早期时间点跟踪肿瘤发展;缺点有三,1)只能靶向有限数量的基因,通常不能反映人类肿瘤细胞的异质性 2)过程昂贵耗时,在明确验证前通常需要几年的工作 3)动物中的肿瘤发展缓慢且多变。文献的文字部分,详细举了一些案例,但是感觉文献时间较早,希望能继续找到近期的一些做比较的文章。
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小擎子 (2022-06-30 23:08):
#paper 10.1158/2159-8290.CD-17-1134 Cancer Discov. The Pancreatic Cancer Microbiome Promotes Oncogenesis by Induction of Innate and Adaptive Immune Suppression 文章要点 1.与正常的胰腺相比,癌性胰腺有明显更丰富的微生物组 2.肿瘤胰腺特定细菌数量有所增加 3.微生物群消融可以防止侵袭前和侵袭性PDA 4.细菌消融与肿瘤微环境免疫原性重编程有关 5. 上述变化包括髓源性抑制细胞的减少和 M1 巨噬细胞分化的增加,促进 CD4 + T 细胞和 CD8 + 的Th1 分化T 细胞活化 6.细菌消融通过上调 PD-1 表达来提高检查点靶向免疫疗法的疗效 7.PDA 微生物组通过差异激活单核细胞中的选择 toll 样受体来产生耐受性免疫程序 8.内源性微生物群促进了 PDA 的免疫抑制特性,微生物组具有作为调节疾病进展的治疗靶点的潜力 9.文章发现独特而丰富的微生物组通过选择性 toll 样受体连接导致 T 细胞无反应性驱动抑制性单核细胞分化。靶向微生物组可防止肿瘤发生、逆转肿瘤内免疫耐受性,并使基于检查点的免疫疗法有效。这些数据对于理解胰腺癌中的免疫抑制及其在临床中的逆转具有重要意义。
IF:29.700Q1 Cancer discovery, 2018-04. DOI: 10.1158/2159-8290.CD-17-1134 PMID: 29567829
Abstract:
We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous … >>>
We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous pancreas compared with gut. Ablation of the microbiome protects against preinvasive and invasive pancreatic ductal adenocarcinoma (PDA), whereas transfer of bacteria from PDA-bearing hosts, but not controls, reverses tumor protection. Bacterial ablation was associated with immunogenic reprogramming of the PDA tumor microenvironment, including a reduction in myeloid-derived suppressor cells and an increase in M1 macrophage differentiation, promoting TH1 differentiation of CD4 T cells and CD8 T-cell activation. Bacterial ablation also enabled efficacy for checkpoint-targeted immunotherapy by upregulating PD-1 expression. Mechanistically, the PDA microbiome generated a tolerogenic immune program by differentially activating select Toll-like receptors in monocytic cells. These data suggest that endogenous microbiota promote the crippling immune-suppression characteristic of PDA and that the microbiome has potential as a therapeutic target in the modulation of disease progression. We found that a distinct and abundant microbiome drives suppressive monocytic cellular differentiation in pancreatic cancer via selective Toll-like receptor ligation leading to T-cell anergy. Targeting the microbiome protects against oncogenesis, reverses intratumoral immune tolerance, and enables efficacy for checkpoint-based immunotherapy. These data have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic. . <<<
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小擎子 (2022-05-31 23:21):
#paper doi:10.1038/nbt.2579 Nat Biotechnol., 2013, Genome sequences of rare, uncultured bacteria obtained by differential coverage binning of multiple metagenomes。用新的差异覆盖分箱方法从环境宏基因组中恢复多个低丰度的物种基因组,为从宏基因组中恢复质量好的MAG提供方法,数据和方法资料齐全,值得参考。
IF:33.100Q1 Nature biotechnology, 2013-Jun. DOI: 10.1038/nbt.2579 PMID: 23707974
Abstract:
Reference genomes are required to understand the diverse roles of microorganisms in ecology, evolution, human and animal health, but most species remain uncultured. Here we present a sequence composition-independent approach … >>>
Reference genomes are required to understand the diverse roles of microorganisms in ecology, evolution, human and animal health, but most species remain uncultured. Here we present a sequence composition-independent approach to recover high-quality microbial genomes from deeply sequenced metagenomes. Multiple metagenomes of the same community, which differ in relative population abundances, were used to assemble 31 bacterial genomes, including rare (<1% relative abundance) species, from an activated sludge bioreactor. Twelve genomes were assembled into complete or near-complete chromosomes. Four belong to the candidate bacterial phylum TM7 and represent the most complete genomes for this phylum to date (relative abundances, 0.06-1.58%). Reanalysis of published metagenomes reveals that differential coverage binning facilitates recovery of more complete and higher fidelity genome bins than other currently used methods, which are primarily based on sequence composition. This approach will be an important addition to the standard metagenome toolbox and greatly improve access to genomes of uncultured microorganisms. <<<
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小擎子 (2022-04-30 21:50):
#paper doi: 10.1126/science.aan4236 Nature, 2017, Gut microbiome modulates response to anti–PD-1 immunotherapy in melanoma patients。发现肠道微生物组可以调节黑色素瘤患者对检查点免疫疗法的反应。患者分为有应答组(R)和无应答组(NR),R组的特点是肠道微生物组有高多样性和丰度的Ruminococcaceae(瘤胃球菌科)/Faecalibacterium(粪杆菌),而NR组的肠道微生物有低多样性和高相对丰度的Bacteroidales(拟杆菌)。通过小鼠模型发现,肠道微生物组通过调节免疫细胞浸润影响了抗肿瘤免疫应答。
Abstract:
Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral … >>>
Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy ( = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples ( = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity ( < 0.01) and relative abundance of bacteria of the Ruminococcaceae family ( < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors. <<<
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小擎子 (2022-03-31 15:29):
#paper doi: 10.1126/science.aah5043 Science, 2017, Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine. 先前已经有研究发现支原体感染的肿瘤细胞培养物中的核苷分解代谢酶会损害抗癌药物吉西他滨的细胞抑制活性。该文献对其机制进行进一步探索,发现人类真皮成纤维细胞(HDF) 的抗生素治疗消除了吉西他滨代谢活性,但用M. hyorhinis(猪支原体)再次感染这些相同的HDF恢复了细胞条件培养基对吉西他滨的代谢;为了确定除支原体以外的细菌是否可以对吉西他滨产生耐药性,文献将分析扩展到 27 种细菌, 27 个物种中有 13 个消除了吉西他滨对 RKO 人结肠直肠癌细胞的影响。经实验发现,CDD是细菌抗吉西他滨的关键基因,CDD的异构体会影响细菌对吉西他滨的代谢能力,CDD L会显著抗吉西他滨,CDD S只有部分代谢吉西他滨的能力。主要是属于Gammaproteobacteria的细菌具有赋予CDD L介导的吉西他滨抗性的潜力。吉西他滨通常用于治疗胰腺导管腺癌 (PDAC),文献假设肿瘤内细菌可能导致这些肿瘤的耐药性,进而对PDAC进行了采样和检测,在测试的 113 个人类 PDAC 中,86 个(76%)对细菌呈阳性,主要是 Gammaproteobacteria。
Abstract:
Growing evidence suggests that microbes can influence the efficacy of cancer therapies. By studying colon cancer models, we found that bacteria can metabolize the chemotherapeutic drug gemcitabine (2',2'-difluorodeoxycytidine) into its … >>>
Growing evidence suggests that microbes can influence the efficacy of cancer therapies. By studying colon cancer models, we found that bacteria can metabolize the chemotherapeutic drug gemcitabine (2',2'-difluorodeoxycytidine) into its inactive form, 2',2'-difluorodeoxyuridine. Metabolism was dependent on the expression of a long isoform of the bacterial enzyme cytidine deaminase (CDD), seen primarily in Gammaproteobacteria. In a colon cancer mouse model, gemcitabine resistance was induced by intratumor Gammaproteobacteria, dependent on bacterial CDD expression, and abrogated by cotreatment with the antibiotic ciprofloxacin. Gemcitabine is commonly used to treat pancreatic ductal adenocarcinoma (PDAC), and we hypothesized that intratumor bacteria might contribute to drug resistance of these tumors. Consistent with this possibility, we found that of the 113 human PDACs that were tested, 86 (76%) were positive for bacteria, mainly Gammaproteobacteria. <<<
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