髄膜炎トラストとMRCがこの作業に資金を提供してくれたことに感謝します。

1. SOE-PCR23による変異アンプリコンの生成とスペクチノマイシンカセットの増幅
<ol><li>まず、株519/43由来のプライ遺伝子の隣接領域の相同性アーム(それぞれply 5'(488 bp)およびply3'(715 bp))の増幅のためにPCRを実行します。プライマー plyFw1_NOTI (TTT GCGGCCGCCAGTAAATGACTTTATTACTATCTATG), ply5'R1_BamHI (CGAAATATAGACCAAAGGACGC GGATCC AGAACCAAACTTGACCTTGA), ply3'F1_BamHI (TCAAGGTCAAGTTTGGTTCTGGATCC GCGTCCTTTGGTCTATATTTCG) および plyRv2_NotI (TTTGCGGCCGCCATTTTCTACCTTTTATCCTCTACC).</li>
	<li>ply5'には次のPCR条件を使用します:94°Cで60秒間変性、ステップ2:94°Cで30秒間変性、ステップ3:58°Cで30秒間アニーリング、ステップ4:72°Cで30秒間伸長、ステップ5:ステップ2に戻って35サイクル繰り返し、ステップ6:72°Cで30秒間の最終伸長。<ol><li>ply3' には、ステップ 4 とステップ 6 の延長時間が 60 秒であることを除いて、同じ PCR 条件を使用します。</li>
	</ol></li>
	<li>ゲル電気泳動によりPCR産物を分析し、ゲルからアンプリコンを切除します。</li>
	<li>製造元の説明書(材料表)に記載されているプロトコルに従ってPCRアンプリコンを精製します。</li>
	<li>SOE-PCRのテンプレートとして、等モル量の両相同性アームを使用します。NOTI (TTT GCGGCCGCCAGTAAATGACTTTATACTAGCTG plyRv2_NotI GGGGGGTGGTGCCATGGCCATGCCATGCCTGCCTGCCTCCTCCTCCTCCTCCTCCTCCTTGCCTCCTCCTTGCCTCCTCCCCTCCTCCCCTCCTCCTCCTTGCCTGGCCTCCTCCTCCTCCTGGCCTGGCCTGGCCTGGCCTGGTTTCCTGGCCTGGCCTGGTTTCCTCCTGGCCTGGTTTCCTCCTCCTGGCCTGGTTTCCTCCTCCTCCTCCTCCTGGCCTGGTTTCCTCCTCCTCCTCCTCCTCCTCTCCCTGGTTGCCTGGCCTGGCCTCCTCCTCC plyFw1_</li>
	<li>以下のSOE-PCR条件を使用します(ステップ1:94°Cで2分間変性、ステップ2:94°Cで30秒間変性、ステップ3:58°Cで30秒間アニーリング、ステップ4:68°Cで60秒間伸長、ステップ5:ステップ2に戻って25サイクル繰り返し、ステップ6:最終伸長を68°Cで90秒間)。</li>
	<li>SOE-PCR産物をゲル電気泳動で分析します。ゲル抽出キットを使用してゲルから切り取り、提供された指示に従ってください。</li>
	<li>以下のPCR条件を用いてプラスミドpR412からスペクチノマイシンカセットを増幅する: ステップ1:94°Cで60秒間変性、 ステップ2:94°Cで30秒間変性、 ステップ3:55°Cで30秒間アニーリング、 ステップ4:68°Cで60秒間伸長、 ステップ5:ステップ2に戻り、25サイクル繰り返します。 ステップ6:68°Cで60秒間の最終延長。<ol><li>プライマー BamHI_SP2F2 (GGATCC CTA GAA CTA GTG GAT CCC CC) および BamHI_SP2R2 (GGATCC AAT TCT GCA GAT TTT AC ATG ATC) を使用してください。プラスミドpR412は、Marc PrudHomme博士(CNRS-ポール・サバティエ・トゥールーズ・フランス大学)から取得しました。</li>
	</ol></li>
	<li>PCRアンプリコンをゲル電気泳動で解析する。得られたPCRアンプリコンを上記のように切り出し精製する。</li>
</ol>2. プラスミドpSD1の生成と 大腸菌 Dh5αの化学変換
<ol><li>pGEMT-easyシステムIの製造元の指示に従ってライゲーションを実行します(材料表)。マイクロ遠心チューブに、5 μLの2xライゲーションバッファー、1 μLのpGEMTeasy、2 μLのply_SOE産物、1 μLのT4 DNAリガーゼおよび水を20 μLの総容量に加えます。4°Cで一晩インキュベートします。 これによりプラスミドpSD1が生成されます。</li>
	<li>化学的に有能な 大腸菌 Dh5αをpSD1で変換します。まず、50 μLの化学的に有能な 大腸菌 Dh5αと3 μLのpSD1ライゲーション反応を氷上で15分間インキュベートします。次に、細胞を熱衝撃(42°C、30秒)にさらして続行します。細胞を氷上に2分間置きます。</li>
	<li>細胞を氷から取り出し、350 μLのS.O.C培地を加えます。培養液を37°C、120rpmで2時間インキュベートする。</li>
	<li>0.4 mM IPTG、青/白選択用の0.24 mg/mL X-Gal、および100 μg/mLアンピシリンを添加したルリアベルタニ寒天培地(LBA)で形質転換をプレート化し、プレート内で増殖するすべてのコロニーがプラスミド骨格を持つようにします。白色コロニーはpSD1を含む。</li>
	<li>3つの白いコロニーを選び、100 μg/mLのアンピシリンを添加した10 mLのLBで一晩増殖させます。培養物を振とうしながら37°Cで一晩インキュベートします。</li>
	<li>翌日、培養液を3,082 x g で遠心分離し、ペレットをプラスミド抽出に使用します。</li>
</ol>3. プラスミドDNA抽出、pSD1およびスペクチノマイシン遺伝子の制限消化およびpSD2のアセンブリ
<ol><li>市販のキットに付属の説明書に従ってプラスミドDNAを抽出します(材料表)。</li>
	<li>pSD1プラスミドと、以前に増幅および精製したスペクチノマイシンカセットの両方に対してBamHI制限消化をセットアップします。 表 1 に記載されている以下の条件と数量を使用してください。</li>
	<li>制限酵素処理反応とコントロールを37°Cで3時間インキュベートします。</li>
	<li>電気泳動で制限ダイジェストを分析し、バンドを切除し、市販のキットに付属の説明書に従って精製します(材料表)。</li>
	<li>次に、BamHI-消化されたpSD1およびスペクチノマイシン(ステップ3.2から)を使用して、製造元の説明書(材料の表)に従ってライゲーション反応を調製する。マイクロ遠心チューブに、5 μLの2xライゲーションバッファー、2 μL pSD1、2 μLのスペクチノマイシンカセット、1 μLのT4 DNAリガーゼの反応成分を加え、4°Cで一晩インキュベートします。 これによりプラスミドpSD2が生成されます。</li>
	<li>プラスミドpSD2を、ステップ2.2に記載の化学的に有能な 大腸菌 Dh5αに形質転換する。</li>
	<li>プラスミドpSD2を保有する形質転換体は、100 μg/mLのスペクチノマイシンとアンピシリンを添加したLBAでの増殖能に基づいて選択します。</li>
	<li>上記のようにプラスミドDNA抽出(pSD2)を実行し、製造元の指示に従って(μL)を実行します。</li>
</ol>4. 肺炎球菌 519/43株の形質転換
<ol><li>S. pneumoniae 519/43をBHIで一晩培養し、37°C、5%CO2で静的に増殖させます。</li>
	<li>翌日、培養物を10 mLの新鮮なBHIブロスで1:50および1:100に希釈します。OD595nm が0.05〜0.1になるまで、培養液を37°Cで静的にインキュベートします(0.1 ODに近いDNAの最適な取得)。</li>
	<li>ODが0.1に達したら、860 μLを取り、マイクロ遠心チューブに移します。この同じマイクロ遠心チューブに、100 μLの100 mM NaOH、10 μLの20%(w/v)BSA、10 μLの100 mM CaCl 2、2 μLの50 ng/mL CSP124 および500 ngのpSD2を追加します。</li>
	<li>反応液を37°Cで3時間静置インキュベートします。</li>
	<li>330 μLを、100 μg/mLのスペクチノマイシンを添加した5%血液寒天プレート(BA)に、3時間かけて1時間ごとにプレートします。</li>
	<li>プレートを37°C、5%CO2で一晩インキュベートします。スペクチノマイシン耐性コロニーを、100 μg/mLのスペクチノマイシンを添加した別のBAプレート、および100 μg/mLのアンピシリンを添加したBAプレートにパッチします。上記の条件下で両方のプレートセットを一晩インキュベートします。アンピシリンプレートは、プラスミド骨格の存在について試験するためのものである。</li>
	<li>NOTI (TTT GCGGCCGCCAGTAAATGACTTTATACTAGCTG) および SPEC_REV (TAATTCCTCTAAGTCTAATTTCCG) plyFw1_プライマーを用いたPCRによりスペクチノマイシンカセットの存在を確認する。変異領域の外側に付着するプライマーplySCN1(CCAATGGAATCGCTAGGCAAGAGATAA)およびplySCN2(ATTACTTAGTCCAACCACGGCTGAT)を用いてPCRにより変異を確認します。</li>
	<li>プライマーplySCN1(CCAATGGAAATCGCTAGGCAAGAGATAA)、plySCN2(ATTACTTAGTCCAACCACGGCTGAT)、およびスペクチノマイシンカセットsqr1(CCTGATCCAACATGTAAGATTACC)sqf2(CGTAGTTATCTTGGAGAATA)spec_sqf1(GGTACTTACATGTTTGGATGGATCAGG)およびspec_sqr2 TATTCTCTCTCCAAGATAACTACGGのそれらの結合部位を有するプライマーを使用してシーケンシングすることにより、ゲノムの正しい位置への組み込みを確認します。</li>
</ol>

<ol>
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W., Yesilkaya, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pneumococcal+6-phospho-&#946;-glucosidase+(BglA3)+is+involved+in+virulence+and+nutrient+metabolism.">Pneumococcal 6-phospho-&#946;-glucosidase (BglA3) is involved in virulence and nutrient metabolism.</a> Infection and Immunity. 84 (1), (2015).</li><li>Harvey, R. M., Ogunniyi, A. D., Chen, A. Y., Paton, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pneumolysin+with+Low+Hemolytic+Activity+Confers+an+Early+Growth+Advantage+to+Streptococcus+pneumoniae+in+the+Blood.">Pneumolysin with Low Hemolytic Activity Confers an Early Growth Advantage to Streptococcus pneumoniae in the Blood.</a> Infection and Immunity. 79 (10), 4122 (2011).</li><li>Terra, V. S., Plumptre, C. D., Wall, E. C., Brown, J. S., Wren, B. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+of+a+pneumolysin+deficient+mutant+in+Streptococcus+pneumoniae+serotype+1+strain+519/43+and+phenotypic+characterisation.">Construction of a pneumolysin deficient mutant in Streptococcus pneumoniae serotype 1 strain 519/43 and phenotypic characterisation.</a> Microbial Pathogenesis. 141, 103999 (2020).</li></ol>

著者は開示するものは何もありません。

肺炎連鎖球菌、特に血清型1は、侵襲性肺炎球菌疾患および髄膜炎を引き起こす世界的な脅威であり続けている。血清型1に対して保護されるべきさまざまなワクチンの導入にもかかわらず、アフリカでは、この血清型は依然として高い罹患率と死亡率につながる発生を引き起こす可能性があります13。この血清型を遺伝的に操作する能力は、その臨床的関連性のために...

肺炎連鎖球菌(S. pneumoniae、肺炎球菌)は、世界的に罹患率と死亡率の主な原因の1つです。最近まで、100近くの血清型のS.肺炎が発見されています1,2,3,4,5,6,7。毎年、侵襲性肺炎球菌疾患(IPD)は、5歳未満の子供の約70万人が死亡していると主張しています8。肺炎球菌は、世界中の細菌性肺炎、中耳炎、髄膜炎、敗血症の主な原因です9。
アフリカの髄膜炎ベルトでは、血清型1が髄膜炎の発生の原因であり、非常に毒性の高い配列型である配列型(ST)ST217が優勢です10、11、12、13、14、15。髄膜炎の病理学におけるその重要性は、アフリカの髄膜炎ベルト16における髄膜炎菌の重要性に例えられています。血清型1はしばしばIPDの主な原因です。しかし、それは非常にまれに馬車で見つかります。実際、ガンビアでは、この血清型はすべての侵襲性疾患の20%を占めていますが、健康な保因者の0.5%にしか見られませんでした14,17,18,19。有能な肺炎球菌における遺伝子交換および組換えは、侵襲性疾患ではなくキャリッジで一般的に起こる20。さらに、血清型1は、肺炎球菌の中で説明されている最も短い保菌率の1つ(わずか9日)を有することが示されている。したがって、この血清型は他の血清型よりもはるかに低い組換え率を有する可能性があることが提案されている21。
血清型1株の保菌率が低い理由と、サハラ以南のアフリカの侵襲性疾患におけるその重要性を理解するには、詳細な研究が必要です。
ここでは、特定の血清型1株、519/43のゲノムワイド突然変異誘発を可能にするプロトコルを報告します。この株は、新しいDNAを簡単に取得してゲノムに組み換えることができます。この方法はまだ系統間ではありませんが、519/43バックグラウンドで行うと非常に効率的です(他のターゲットは変異しており、原稿は準備中です)。519/43株を使用し、その自然な能力を利用し、外因性DNAの提供方法を置き換えるだけで、この血清型1株のニューモリシン遺伝子(プライ)を変異させることができました。この方法は、異なる血清型を介してDNAを通過させる必要なしにワンステップで行われるため、Harveyら22 によって提示されたものの改良を表しています。それにもかかわらず、また株間の変動性のために、すべての菌株に標準化された方法はありません。特定の遺伝子を変異させ、その効果を観察する能力は、血清型 1 S. pneumoniae 株の深い理解を可能にし、サハラ以南のアフリカの髄膜炎におけるこれらの株の役割についての答えを提供します。

<table><tbody><tr><td>AccuPrime &lt;em&gt;Pfx&lt;/em&gt; DNA polymerase</td><td>Invitrogen</td><td>12344024</td><td>Used for amplification of the fragments</td></tr><tr><td>Ampicillin sodium salt</td><td>Sigma Aldrich</td><td>A9518</td><td>Used for bacterial selection on stage 1(pSD1)</td></tr><tr><td>Blood Agar Base</td><td>Oxoid</td><td>CM0055</td><td>Used to plate &lt;em&gt;S. pneumoniae&lt;/em&gt; transformants</td></tr><tr><td>Bovine Serum Albumine</td><td>sigma</td><td>55470</td><td>used for &lt;em&gt;S. pneumoniae&lt;/em&gt; Transformation</td></tr><tr><td>Brain Heart Infusion</td><td>Oxoid</td><td>CM1135</td><td>used to grow &lt;em&gt;S. pneumoniae&lt;/em&gt; cells</td></tr><tr><td>Calcium Chloride Cacl&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma</td><td>449709</td><td>used for &lt;em&gt;S. pneumoniae&lt;/em&gt; Transformation</td></tr><tr><td>Competence stimulating peptide 1</td><td>AnaSpec</td><td>AS-63779</td><td>used for &lt;em&gt;S. pneumoniae&lt;/em&gt; Transformation</td></tr><tr><td>Luria Broth Agar</td><td>Gibco</td><td>22700025</td><td>used for plating and selection of pSD1 and pSD2</td></tr><tr><td>Luria Broth Base (Miller&#039;s formulation)</td><td>Gibco</td><td>12795027</td><td>used for plating and selection of pSD1 and pSD2</td></tr><tr><td>Monarch Gel Extraction Kit</td><td>NEB</td><td>T1020S</td><td>Used to extract the bands from the DNA gel</td></tr><tr><td>Monarch Plasmid Miniprep Kit</td><td>NEB</td><td>T1010S</td><td>Used to extract plasmid from the cells</td></tr><tr><td>pGEM T-easy</td><td>Promega</td><td>A1360</td><td>used as suicide plasmid</td></tr><tr><td>S.O.C.</td><td>Invitrogen</td><td>15544034</td><td>used for recovery of cells after transformation</td></tr><tr><td>Sodium Hydroxide (NaOH)</td><td>Sigma</td><td>S0899</td><td>used for &lt;em&gt;S.pneumoniae&lt;/em&gt; Transformation</td></tr><tr><td>Spectinomycin Hydrochloride</td><td>SigmaAldrich</td><td>PHR1426</td><td>Used for bacterial selection</td></tr><tr><td>Subcloning Efficiency DH5&amp;alpha; Competent Cells</td><td>Invitrogen</td><td>18265017</td><td>used for the creation of pSD1 and pSD2</td></tr></tbody></table>

constructing mutants in serotype 1 streptococcus pneumoniae strain 519/43

肺炎連鎖球菌 血清型1は、低中所得国、特にサハラ以南のアフリカで依然として大きな問題となっています。その重要性にもかかわらず、この血清型の研究は、それを改変するための遺伝的ツールの欠如によって妨げられてきました。本研究では、血清型1臨床分離株(株519/43)を遺伝子改変する方法について述べる。興味深いことに、これは肺炎球菌が自然にDNAを取得する能力を利用することによって達成されました。しかし、ほとんどの肺炎球菌とは異なり、線状DNAの使用は成功しませんでした。この重要な株を変異させるには、自殺プラスミドを使用する必要がありました。この方法論は、その生物学と病原性の両方の観点から、このとらえどころのない血清型をより深く理解するための手段を提供しました。この方法を検証するために、主要な既知の肺炎球菌毒素であるニューモリシンは、よく知られたわかりやすい表現型を持っているため、変異しました。予想通り、突然変異体が赤血球を溶解する能力を失ったことを示しました。目的の血清型で重要な遺伝子を変異させることができれば、腹腔内および鼻腔内感染時の機能喪失変異体の表現型が他の血清型で観察されたものとは異なる表現型を観察することができました。要約すると、この研究は、株519/43(血清型1)が遺伝子組み換え可能であることを証明しています。

ここで説明するプロトコルは、PCRを使用して左右の相同性アームを増幅すると同時に、 プライ 遺伝子の中央領域から191 bpを削除することから始まります。PCRを実行している間、BamHI部位が左相同性アームの3'側および右相同性アームの5'末端に導入されます(図1A)。これに続いて、左右の相同性アームが1つのアンプリコンに融合されたPCR-SOEが続きます(<strong class="x...

Watch this Scientific Journal Video about Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43 at JoVE.com

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

ここでは、自然にDNAを獲得する能力を利用して遺伝子改変できる 肺炎球 菌血清型1株519/43と自殺プラスミドについて述べる。原理の証明として、ニューモリシン(プライ)遺伝子の同質変異体が作られました。

血清型1肺 炎球 菌519/43株における変異体の構築

Streptococcus pneumoniae serotype 1 remains a huge problem in low-and-middle income countries, particularly in sub-Saharan Africa. Despite its importance, ...

constructing-mutants-serotype-1-streptococcus-pneumoniae-strain

Research

JoVE Journal

Immunology and Infection

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

1.6K ビュー.  London School of Hygiene and Tropical Medicine. ここでは、自然にDNAを獲得する能力を利用して遺伝子改変できる 肺炎球 菌血清型1株519/43と自殺プラスミドについて述べる。原理の証明として、ニューモリシン(プライ)遺伝子の同質変異体が作られました。

ビデオ: Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

Generation of a Gene-disrupted Streptococcus mutans Strain Without Gene Cloning

Typical methods for the elucidation of the function of a particular gene involve comparative phenotypic analyses of the wild-type strain and a strain in which the gene of interest has been disrupted. A gene-disruption DNA construct containing a suitable antibiotic resistance marker gene is useful for the generation of gene-disrupted strains in bacteria. However, conventional construction methods, which require gene cloning steps, involve complex and time-consuming protocols. Here, a relatively facile, rapid, and cost-effective method for targeted gene disruption in Streptococcus mutans is described. The method utilizes a 2-step fusion polymerase chain reaction (PCR) to generate the disruption construct and electroporation for genetic transformation. This method does not require an enzymatic reaction, other than PCR, and additionally offers greater flexibility in terms of the design of the disruption construct. Employment of electroporation facilitates the preparation of competent cells and improves the transformation efficiency. The present method may be adapted for the generation of gene-disrupted strains of various species.

Generation of a Gene-disrupted Streptococcus mutans Strain Without Gene Cloning

We describe a facile, rapid, and relatively inexpensive method for the generation of gene-disrupted Streptococcus mutans strains; this technique may be adapted for the generation of gene-disrupted strains of various species.

遺伝子破壊ミュータンス連鎖球菌緊張せず遺伝子クローニングの生成

Typical methods for the elucidation of the function of a particular gene involve comparative phenotypic analyses of the wild-type strain and a strain in ...

遺伝学

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite to invasion to the lungs or bloodstream1. This organism is capable of colonizing the mucosal surface of the nasopharynx, where it can reside, multiply and eventually overcome host defences to invade to other tissues of the host. Establishment of an infection in the normally lower respiratory tract results in pneumonia. Alternatively, the bacteria can disseminate into the bloodstream causing bacteraemia, which is associated with high mortality rates2, or else lead directly to the development of pneumococcal meningitis. Understanding the kinetics of, and immune responses to, nasopharyngeal colonization is an important aspect of S. pneumoniae infection models.
Our mouse model of intranasal colonization is adapted from human models3 and has been used by multiple research groups in the study of host-pathogen responses in the nasopharynx4-7. In the first part of the model, we use a clinical isolate of S. pneumoniae to establish a self-limiting bacterial colonization that is similar to carriage events in human adults. The procedure detailed herein involves preparation of a bacterial inoculum, followed by the establishment of a colonization event through delivery of the inoculum via an intranasal route of administration. Resident macrophages are the predominant cell type in the nasopharynx during the steady state. Typically, there are few lymphocytes present in uninfected mice8, however mucosal colonization will lead to low- to high-grade inflammation (depending on the virulence of the bacterial species and strain) that will result in an immune response and the subsequent recruitment of host immune cells. These cells can be isolated by a lavage of the tracheal contents through the nares, and correlated to the density of colonization bacteria to better understand the kinetics of the infection.

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Colonization of the murine nasopharynx with Streptococcus pneumoniae and the subsequent extraction of adherent or recruited cells is described. This technique involves flushing the nasopharynx and collection of the fluid through the nares and is adaptable for various readouts, including differential cell quantification and analysis of mRNA expression in situ.

肺炎球菌による鼻腔内コロニー形成時の炎症反応の特徴

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite to invasion to the lungs or bloodstream1. This organism is capable of colonizing ...

免疫・感染学

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria

Pneumonia is one of the major health care problems in developing and industrialized countries and is associated with considerable morbidity and mortality. Despite advances in knowledge of this illness, the availability of intensive care units (ICU), and the use of potent antimicrobial agents and effective vaccines, the mortality rates remain high1. Streptococcus pneumoniae is the leading pathogen of community-acquired pneumonia (CAP) and one of the most common causes of bacteremia in humans. This pathogen is equipped with an armamentarium of surface-exposed adhesins and virulence factors contributing to pneumonia and invasive pneumococcal disease (IPD). The assessment of the in vivo role of bacterial fitness or virulence factors is of utmost importance to unravel S. pneumoniae pathogenicity mechanisms. Murine models of pneumonia, bacteremia, and meningitis are being used to determine the impact of pneumococcal factors at different stages of the infection. Here we describe a protocol to monitor in real-time pneumococcal dissemination in mice after intranasal or intraperitoneal infections with bioluminescent bacteria. The results show the multiplication and dissemination of pneumococci in the lower respiratory tract and blood, which can be visualized and evaluated using an imaging system and the accompanying analysis software.

Streptococcus pneumoniae is the leading pathogen causing severe community-acquired pneumonia and responsible for over 2&#160;million deaths worldwide. The impact of bacterial factors implicated in fitness or virulence can be monitored in real-time in an acute mouse pneumonia or bacteremia model using bioluminescent bacteria.

生物発光細菌を使用してリアルタイムに急性肺炎のマウスモデルにおける肺炎球菌の毒性因子の影響を以下の

Pneumonia is one of the major health care problems in developing and industrialized countries and is associated with considerable morbidity and mortality. ...

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

There are over 90 different capsular serotypes of Streptococcus pneumoniae (the pneumococcus). As well as being a tool for understanding pneumococcal epidemiology, capsular serotyping can provide useful information for vaccine efficacy and impact studies.&#160;The Quellung reaction is the gold standard method for pneumococcal capsular serotyping. The method involves testing a pneumococcal cell suspension with pooled and specific antisera directed against the capsular polysaccharide. The antigen-antibody reactions are observed microscopically. The protocol has three main steps: 1) preparation of a bacterial cell suspension, 2) mixing of cells and antisera on a glass slide, and 3) reading the Quellung reaction using a microscope. The Quellung reaction is reasonably simple to perform and can be applied wherever a suitable microscope and antisera are available.

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

The Quellung reaction is the gold standard technique for serotyping Streptococcus pneumoniae. This technique utilizes a microscope and specific pneumococcal antisera and is commonly used in reference and research laboratories worldwide.

の莢血清型<em&gt;肺炎球菌</em&gt;膨張反応を使用して、

There are over 90 different capsular serotypes of Streptococcus pneumoniae (the pneumococcus). As well as being a tool for understanding pneumococcal ...

Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling

During bacteremia Streptococcus pneumoniae can translocate across the vascular endothelium into the myocardium and form discrete bacteria-filled microscopic lesions (microlesions) that are remarkable due to the absence of infiltrating immune cells. Due to their release of cardiotoxic products, S. pneumoniae within microlesions are thought to contribute to the heart failure that is frequently observed during fulminate invasive pneumococcal disease in adults. Herein is demonstrated a protocol for experimental mouse infection that leads to reproducible cardiac microlesion formation within 30 hr. Instruction is provided on microlesion identification in hematoxylin &#38; eosin stained heart sections and the morphological distinctions between early and late microlesions are highlighted. Instruction is provided on a protocol for verification of S. pneumoniae within microlesions using antibodies against pneumococcal capsular polysaccharide and immunofluorescent microscopy. Last, a protocol for antibiotic intervention that rescues infected mice and for the detection and assessment of scar formation in the hearts of convalescent mice is provided. Together, these protocols will facilitate the investigation of the molecular mechanisms underlying pneumococcal cardiac invasion, cardiomyocyte death, cardiac remodeling as a result of exposure to S. pneumoniae, and the immune response to the pneumococci in the heart.

Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling

Streptococcus pneumoniae forms discrete non-purulent microscopic lesions in the heart. Outlined is the protocol for a murine model of cardiac microlesion formation. Instruction is provided on microlesion visualization using microscopy, discrimination between early and late microlesions, and methods to detect cardiac remodeling in hearts of convalescent animals.

の可視化<em&gt;肺炎球菌</em&gt;心臓Microlesionsとその後の心臓リモデリングの中

During bacteremia Streptococcus pneumoniae can translocate across the vascular endothelium into the myocardium and form discrete bacteria-filled ...

医学

Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants

Pseudomonas aeruginosa is a phenotypically and genotypically diverse and adaptable Gram-negative bacterium ubiquitous in human environments. P. aeruginosa is able to form biofilms, develop antibiotic resistance, produce virulence factors, and rapidly evolve in the course of a chronic infection. Thus P. aeruginosa can cause both acute and chronic, difficult to treat infections, resulting in significant morbidity in certain patient populations. P. aeruginosa strain PA14 is a human clinical isolate with a conserved genome structure that infects a variety of mammalian and nonvertebrate hosts making PA14 an attractive strain for studying this pathogen. In 2006, a nonredundant transposon insertion mutant library containing 5,459 mutants corresponding to 4,596 predicted PA14 genes was generated. Since then, distribution of the PA14 library has allowed the research community to better understand the function of individual genes and complex pathways of P. aeruginosa. Maintenance of library integrity through the replication process requires proper handling and precise techniques. To that end, this manuscript presents protocols that describe in detail the steps involved in library replication, library quality control and proper storage of individual mutants.

Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants

Pseudomonas aeruginosa infection causes significant morbidity in vulnerable hosts. The nonredundant transposon insertion mutant library of P. aeruginosa strain PA14, designated as PA14NR Set, facilitates analysis of gene functionality in numerous processes. Presented here is a protocol to generate high-quality copies of the PA14NR Set mutant library.

発注済み、緑膿菌ひずみ PA14 トランスポゾン挿入変異体の非冗長ライブラリのレプリケーション

Pseudomonas aeruginosa is a phenotypically and genotypically diverse and adaptable Gram-negative bacterium ubiquitous in human environments. P. aeruginosa ...

Homogeneous Glycoconjugate Produced by Combined Unnatural Amino Acid Incorporation and Click-Chemistry for Vaccine Purposes

Genetic code expansion is a powerful tool to introduce unnatural amino acids (UAAs) into proteins to modify their characteristics, to study or create new protein functions or to have access to protein conjugates. Stop codon suppression, in particular amber codon suppression, has emerged as the most popular method to genetically introduce UAAs at defined positions. This methodology is herein applied to the preparation of a carrier protein containing an UAA harboring a bioorthogonal functional group. This reactive handle can next be used to specifically and efficiently graft a synthetic oligosaccharide hapten to provide a homogeneous glycoconjugate vaccine. The protocol is limited to the synthesis of glycoconjugates in a 1:1 carbohydrate hapten/carrier protein ratio but amenable to numerous pairs of biorthogonal functional groups. Glycococonjugate vaccine homogeneity is an important criterion to ensure complete physico-chemical characterization, thereby, satisfying more and more demanding drug regulatory agency recommendations, a criterion which is unmet by classical conjugation strategies. Moreover, this protocol makes it possible to finely tune the structure of the actual conjugate vaccine, giving rise to tools to address structure-immunogenicity relationships.

Genetic code expansion is applied for the introduction of an unnatural amino acid bearing a biorthogonal functional group on a carrier protein at a defined site. The biorthogonal function is further used for the site-selective coupling of a carbohydrate antigen to provide a homogeneous glycoconjugate vaccine.

ワクチン用非天然アミノ酸組み合わせとクリック化学を組み合わせた均質なグリココンジュゲート

Genetic code expansion is a powerful tool to introduce unnatural amino acids (UAAs) into proteins to modify their characteristics, to study or create new ...

生物工学

Purification of a High Molecular Mass Protein in Streptococcus mutans

Elucidation of a gene&#39;s function typically involves comparison of phenotypic traits of wild-type strains and strains in which the gene of interest has been disrupted. Loss of function following gene disruption is subsequently restored by exogenous addition of the product of the disrupted gene. This helps to determine the function of the gene. A method previously described involves generating a gtfC gene-disrupted Streptococcus mutans strain. Here, an undemanding method is described for purifying the gtfC gene product from the newly generated S. mutans strain following the gene disruption. It involves the addition of a polyhistidine-coding sequence at the 3&#8242; end of the gene of interest, which allows simple purification of the gene product using immobilized metal affinity chromatography. No enzymatic reactions other than PCR are required for the genetic modification in this method. The restoration of the gene product by exogenous addition after gene disruption is an efficient method for determining gene function, which may also be adapted to different species.

Purification of a High Molecular Mass Protein in Streptococcus mutans

Described here is a simple method for the purification of a gene product in Streptococcus mutans. This technique may be advantageous in the purification of proteins, especially membrane proteins and high molecular mass proteins, and can be used with various other bacterial species.

連鎖球菌変異体における高分子塊タンパク質の精製

Elucidation of a gene&#39;s function typically involves comparison of phenotypic traits of wild-type strains and strains in which the gene of interest has ...

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery

Neisseria meningitidis (meningococcus) is a narrow-host-range microorganism, globally recognized as the leading cause of bacterial meningitis. Meningococcus is a transient colonizer of human nasopharynx of approximately 10% of healthy subject. In particular circumstances, it acquires an invasive ability to penetrate the mucosal barrier and invades the bloodstream causing septicaemia. In the latest case, fulminating sepsis could arise even without the consequent development of meningitis. Conversely, bacteria could poorly multiply in the bloodstream, cross the blood brain barrier, reach the central nervous system, leading to fulminant meningitis. The murine models of bacterial meningitis represent a useful tool to investigate the host-pathogen interactions and to analyze the pathogenetic mechanisms responsible for this lethal disease. Although, several experimental model systems have been evaluated over the last decades, none of these were able to reproduce the characteristic pathological events of meningococcal disease. In this experimental protocol, we describe a detailed procedure for the induction of meningococcal meningitis in a mouse model based on the intracisternal inoculation of bacteria. The peculiar signs of human meningitis were recorded in the murine host through the assessment of clinical parameters (e.g., temperature, body weight), evaluation of survival rate, microbiological analysis and histological examination of brain injury. When using intracisternal (i.cist.) inoculum, meningococci complete delivery directly into cisterna magna, leading to a very efficient meningococcal replication in the brain tissue. A 1,000-fold increase of viable count of bacteria is observed in about 18 h. Moreover, meningococci are also found in the spleen, and liver of infected mice, suggesting that the liver may represent a target organ for meningococcal replication.

Here, we describe a method to induce meningococcal meningitis through an intracisternal route of infection in adult mice. We present a step by step protocol of meningococcal infection from the preparation of inoculum to the intracisternal infection; then record the animal survival and evaluate the bacterial loads in murine tissues.

インティリカレルナルデリバリーによるマウスにおける髄膜炎球炎血清群Cの誘導

Neisseria meningitidis (meningococcus) is a narrow-host-range microorganism, globally recognized as the leading cause of bacterial meningitis. ...

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection

Microorganisms are genetically versatile and diverse and have become a major source of many commercial products and biopharmaceuticals. Though some of these products are naturally produced by the organisms, other products require genetic engineering of the organism to increase the yields of production. Avirulent strains of Escherichia coli have traditionally been the preferred bacterial species for producing biopharmaceuticals; however, some products are difficult for E. coli to produce. Thus, avirulent strains of other bacterial species could provide useful alternatives for production of some commercial products. Pseudomonas aeruginosa is a common and well-studied Gram-negative bacterium that could provide a suitable alternative to E. coli. However, P. aeruginosa is an opportunistic human pathogen. Here, we detail a procedure that can be used to generate nonpathogenic strains of P. aeruginosa through sequential genomic deletions using the pEX100T-NotI plasmid. The main advantage of this method is to produce a marker-free strain. This method may be used to generate highly attenuated P. aeruginosa strains for the production of commercial products, or to design strains for other specific uses. We also describe a simple and reproducible mouse model of bacterial systemic infection via intraperitoneal injection of validated test strains to test the attenuation of the genetically engineered strain in comparison to the FDA-approved BL21 strain of E. coli.

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection

Here, we describe a simple and reproducible protocol of mouse model of infection to evaluate the attenuation of the genetically modified strains of Pseudomonas aeruginosa in comparison to the United States Food and Drug Administration (FDA)-approved Escherichia coli for commercial applications.

緑膿菌におけるフレーム内遺伝子欠失変異体の生成と感染の単純マウスモデルにおける毒性減衰の試験

Microorganisms are genetically versatile and diverse and have become a major source of many commercial products and biopharmaceuticals. Though some of ...

血清型1肺炎球菌519/43株における変異体の構築

要約

さらに動画を探す

この動画の章

遺伝子破壊ミュータンス連鎖球菌緊張せず遺伝子クローニングの生成

肺炎球菌による鼻腔内コロニー形成時の炎症反応の特徴

生物発光細菌を使用してリアルタイムに急性肺炎のマウスモデルにおける肺炎球菌の毒性因子の影響を以下の

の莢血清型

の可視化

発注済み、緑膿菌ひずみ PA14 トランスポゾン挿入変異体の非冗長ライブラリのレプリケーション

ワクチン用非天然アミノ酸組み合わせとクリック化学を組み合わせた均質なグリココンジュゲート

連鎖球菌変異体における高分子塊タンパク質の精製

インティリカレルナルデリバリーによるマウスにおける髄膜炎球炎血清群Cの誘導

緑膿菌におけるフレーム内遺伝子欠失変異体の生成と感染の単純マウスモデルにおける毒性減衰の試験

血清型1肺 炎球 菌519/43株における変異体の構築

要約

さらに動画を探す

この動画の章

遺伝子破壊ミュータンス連鎖球菌緊張せず遺伝子クローニングの生成

肺炎球菌による鼻腔内コロニー形成時の炎症反応の特徴

生物発光細菌を使用してリアルタイムに急性肺炎のマウスモデルにおける肺炎球菌の毒性因子の影響を以下の

の莢血清型

の可視化

発注済み、緑膿菌ひずみ PA14 トランスポゾン挿入変異体の非冗長ライブラリのレプリケーション

ワクチン用非天然アミノ酸組み合わせとクリック化学を組み合わせた均質なグリココンジュゲート

連鎖球菌変異体における高分子塊タンパク質の精製

インティリカレルナルデリバリーによるマウスにおける髄膜炎球炎血清群Cの誘導

緑膿菌におけるフレーム内遺伝子欠失変異体の生成と感染の単純マウスモデルにおける毒性減衰の試験

血清型1肺炎球菌519/43株における変異体の構築