BioVector® pNW33N-GFP Thermophilic Shuttle Reporter Vector / pNW33N-GFP 嗜热细菌发酵与质粒穿梭荧光报告载体

一 产品基本信息与分子生物学背景

• 载体名称：pNW33N-GFP。

• 载体分类：广宿主、嗜热/原核穿梭型荧光报告质粒（大肠杆菌与地衣/枯草/嗜热脂肪芽孢杆菌穿梭）。

• 质粒大小：约 6.0 - 6.5 kb。

• 骨架源起与设计背景：pNW33N-GFP 是一款专门用于革兰氏阳性嗜热细菌（Thermophilic bacteria）及普通芽孢杆菌中进行基因表达调控、启动子强度示踪的功能性穿梭报告质粒。其原型骨架基于经典的广宿主低拷贝质粒 pNW33N（派生自金黄色葡萄球菌质粒 pUB110 的特异性复制子）。传统的质粒在超过 50 摄氏度的高温发酵环境下，由于其复制酶（Rep 蛋白）和抗性选择标记蛋白会发生剧烈的热变性，极易发生质粒整株丢失（Plasmid loss）。pNW33N 骨架由于配置了高度耐热的复制控制元件（Thermophilic Replicon），使得该质粒能够耐受高达 55 ℃ - 65 ℃ 的极端高温，是全球研究嗜热脂肪芽孢杆菌（Geobacillus stearothermophilus）和地衣芽孢杆菌（Bacillus lichemiformis）的黄金标准底盘。

• 核心顺式作用元件与图谱特征：

  • GFP 荧光报告表达夹层（GFP Reporter Cassette）：在多克隆位点（MCS）中，原装嵌入了绿色荧光蛋白（Green Fluorescent Protein, GFP）的完整开放阅读框。其上游通常配有一个中等强度的芽孢杆菌结构性启动子（或留出独特的克隆位点用于插入待测的未知启动子片段），用于在活菌体内直接进行可视化和定量化的荧光亮度检测。

  • 耐热型氯霉素抗性基因（高温变体 $Cm^R$ / $cat$）：这是该载体在极端环境下运行的核心。它携带的氯霉素乙酰转移酶（CAT）突变体具有极高的热稳定性，在 55 ℃ 以上的高温培养基中依然能保持完美的空间构象，赋予阳性转化子极其强健的氯霉素耐药表型。

  • 大肠杆菌复制子与抗性：含有 pUC ori 和 氨苄青霉素抗性基因（$Amp^R$），专门用于前期在大肠杆菌（E. coli）中进行极为高效、常规的分子克隆、重组以及质粒大抽提。

二 核心科研价值与工业发酵转化应用

pNW33N-GFP 质粒在高温微生物学、极端工业发酵及合成生物学中占有核心一席：

1. 高温工业发酵菌株的体外动态示踪与生物量测定：嗜热脂肪芽孢杆菌等工业菌株常用于生产高温淀粉酶、脂酶或进行高温乙醇发酵，发酵罐温度通常维持在 60 ℃ 左右。利用 pNW33N-GFP 转化工业菌株后，由于 GFP 在细胞内随菌体增殖而同步积累，科研人员无需抽样计数，直接利用酶标仪在体外测定 510 nm 发射波长下的荧光强度（Fluorescence Intensity），即可在不破坏发酵环境的条件下，极其精准地实时在线监测高温工业发酵的细菌生物量（Biomass）波动与活菌空间分布。

2. 极端嗜热菌未知强启动子的高通量体外筛选（Promoter Trapping）：利用多克隆位点切掉 GFP 上游的原有启动子，将来自极端环境宿主基因组的乱序 DNA 片段文库克隆入其上方。转化入地衣芽孢杆菌后，直接在高温平板上利用紫外透射仪或蓝光透射仪进行肉眼扫视。凡是发出耀眼绿色荧光的菌落，说明其插入片段内包裹着一个能在极端高温下强力驱动转录的“超级耐热启动子”。这是挖掘新型耐热工业表达元件的标配技术路线。

3. 高温高盐恶劣环境下的胞内病理生理状态监测：用于评估工业发酵中，底物浓度过高（渗透压激增）、代谢产物毒性累积（如乙醇浓度飙升）或热休克（Heat shock）压力对细菌胞内蛋白质合成大系统的实时损伤程度。通过监测 GFP 荧光的淬灭速度与折叠状态，解构极端菌的应激防御机制。

三 实验室大肠克隆、芽孢/嗜热菌转化、发酵与荧光测定标准步骤

1. 质粒在大肠杆菌（E. coli）中的分子克隆与高质纯化

• 转化与平板筛选：将环状的 pNW33N-GFP 质粒（或连接产物）通过热击法转化入常规大肠杆菌（如 DH5$\alpha$ 或 TOP10）感受态中。均匀涂布于含有 100 $\mu$g/mL 氨苄青霉素（Ampicillin）的常规 LB 固体平板上，37 ℃ 避光培养过夜。

• 液体扩增与质控：挑取单菌落接种于 LB 液体培养基中（100 $\mu$g/mL 氨苄青霉素），37 ℃ 振荡扩增 12 - 14 小时。使用优质质粒纯化试剂盒提取质粒 DNA，由于 pNW33N 属于中低拷贝穿梭质粒，建议适当增加菌量或延长吸附柱平衡时间，以确保洗脱出的质粒浓度 $\ge 200\text{ ng/}\mu\text{L}$，纯度 $OD_{260}/OD_{280} = 1.80 - 1.90$。

2. 枯草/地衣/嗜热芽孢杆菌的电转化操作（High-Voltage Electroporation）

革兰氏阳性芽孢杆菌及嗜热菌具有极其厚实的肽聚糖细胞壁，常规化学转化效率极低，临床及科研上强烈推荐使用高效高压电击法（Electroporation）。

1. 高渗感受态制备（以嗜热脂肪芽孢杆菌为例）：

   • 将宿主菌接种于富含营养的富集培养基（如 TBY 培养基）中，在宿主最适生长温度（如 55 ℃ - 60 ℃）下剧烈振荡培养至对数生长中期（$OD_{600} \approx 0.4-0.6$）。

   • 立刻将菌液置于冰水混合物中冷激 30 分钟，逼迫其终止增殖。

   • 4 ℃ 高速离心收集菌体，使用冰透的高渗洗涤缓冲液（配方：0.5 M 蔗糖 Sucrose, 10% 甘油 Glycerol, 1 mM $MgCl_2$）连续反复洗涤细胞 3 - 4 次，以彻底清除培养基中的电导盐离子。最终用少量高渗缓冲液悬浮，分装作为高电转效率的感受态细胞。

2. 脉冲电击转化：

   • 吸取 60 - 80 $\mu$L 的高渗感受态细胞，加入 1 - 2 $\mu$g 的高纯度 pNW33N-GFP 质粒 DNA，混匀后极其小心地注入预冷的 0.2 cm 间距专业电转杯中，冰上静置 2 分钟。

   • 将电转杯插入电调谐仪（如 Bio-Rad Gene Pulser）。设置核心电击参数：电压 2.0 - 2.5 kV，电容 25 $\mu\text{F}$，电阻 200 - 400 $\Omega$。启动电击，脉冲时间（Time constant）通常处于 4.5 - 5.5 毫秒之间。

3. 高温高渗复苏（关键控制点）：

   • 电击完成的瞬间，必须在 5 秒钟内立刻向电转杯中注入 1 mL 预热至 50 ℃ 且富含高高渗蔗糖的复苏培养基（如含有 0.5 M 蔗糖的 LB 液体培养基），轻柔吹打。

   • 将菌液转移入离心管中，置于对应嗜热菌的复苏温度（通常为 45 ℃ - 50 ℃，注意：复苏时为了让电击受损的细胞膜恢复，温度不要升到极端的 60 ℃，稍微降低温度更有利于膜修复）下，温和低速（100 rpm）振荡复苏 1.5 - 2 小时。

3. 高温抗生素筛选与绿色荧光（GFP）定量化测定

1. 高温抗生素平板初筛：将复苏后的菌液均匀涂布于含有 5 - 10 $\mu$g/mL 氯霉素（Chloramphenicol）的高渗 LB 固体平板上。将平板倒置，放入高温恒温生化培养箱中，在 55 摄氏度 - 60 摄氏度 的目标发酵高温下，遮光暗培养 24 - 36 小时。由于 pNW33N 的耐热复制子和耐热 CAT 酶工作极其稳定，真正的转化子能形成边缘清晰、圆润饱满的阳性单菌落。

2. 绿色荧光（GFP）的可视化与定量化分析：

   • 肉眼初筛：直接将长有菌落的平板放置于 488 nm 蓝光透射仪或紫外成像仪上。在顺式启动子驱动下，真正的 pNW33N-GFP 转化株会直接在暗室中暴射出极其耀眼、明亮的黄绿色荧光。

   • 液体发酵与荧光定量检测（酶标仪法）：挑取发光的单菌落，接种于含有 10 $\mu$g/mL 氯霉素的液体发酵培养基中，在 60 ℃ 下进行高温摇瓶发酵。在不同的时间节点（如 4h, 8h, 12h, 24h）抽取 100 $\mu$L 发酵粗提液，直接注入黑色 96 孔荧光专用酶标板中。设定检测参数：激发波长（Excitation Wavelength）固定为 485 nm - 488 nm，发射波长（Emission Wavelength）固定为 510 nm - 515 nm。读取各孔的相对荧光单位（Relative Fluorescence Units, RFU），同时测定该样品的 $OD_{600}$ 菌密度值。利用 $\text{RFU} / OD_{600}$ 的比值，即可完全消除菌体浓度差异带来的干扰，精准、定量地评估外源基因在极端高温环境下的真实转录表达效率。

Part 2 English Section

I General Information and Molecular Biological Background

• Vector Name: pNW33N-GFP.

• Vector Classification: Broad-host-range, thermophilic prokaryotic shuttle reporter plasmid (shuttles effectively between Escherichia coli and Bacillus/Geobacillus strains).

• Plasmid Size Scale: Approximately 6.0 - 6.5 kb.

• Backbone Origin and Engineering Background:The pNW33N-GFP shuttle reporter vector is a specialized tool engineered to investigate transcription profiles, screen promoter strengths, and monitor biomass kinetics inside Gram-positive thermophilic bacteria and legacy Bacillus lineages. Its baseline architecture is derived from the broad-host, low-copy plasmid pNW33N (which incorporates a highly stable replicon derived from the Staphylococcus aureus plasmid pUB110).Standard episomal vectors used in industrial fermentations exceeding 50 °C typically undergo catastrophic plasmid loss due to thermal denaturation of their replication determinants (Rep proteins) and selection markers. The pNW33N backbone resolves this biological constraint by harboring a specialized thermophilic replicon capable of maintaining structural stability and inheritance fidelity during sustained, extreme cultivation temperatures ranging from 55 °C to 65 °C, establishing it as a gold-standard cloning platform for Geobacillus stearothermophilus and Bacillus licheniformis.

• Core Cis-Acting Elements and Map Characterization:

  • GFP Expression Reporter Cassette: The Multiple Cloning Site (MCS) houses a fully integrated open reading frame encoding Green Fluorescent Protein (GFP). This reporter is standardly driven by a baseline constitutive Bacillus promoter positioned upstream (or left open via distinct restriction sites to permit the insertional trapping of uncharacterized external promoters) to enable real-time visualization and precise measurement of intracellular green fluorescence.

  • Thermostable Chloramphenicol Resistance Gene (High-Temperature $Cm^R$ / $cat$ Variant): Represents the engineering core that permits selection under extreme temperatures. It encodes a mutant variant of Chloramphenicol Acetyltransferase (CAT) that preserves its tertiary spatial configuration and catalytic activity above 55 °C, conferring robust chloramphenicol resistance to host transfectants.

  • E. coli Replication & Selection Domain: Formulated with a standard pUC ori and a functional Ampicillin resistance gene ($Amp^R$ / bla), allowing investigators to perform high-efficiency initial molecular cloning, sequencing validation, and high-yield plasmid extractions inside Escherichia coli hosts.

II Strategic Research Value and Industrial Fermentation Applications

The pNW33N-GFP plasmid serves crucial exploratory and monitoring functions in thermophilic microbiology and industrial scale-up pipelines:

1. Real-Time Biomass Tracking and Spatiotemporal Mapping in High-Temperature Fermenters:Thermophilic bacilli are widely deployed in commercial fermenters at temperatures around 60 °C to manufacture thermostable amylases, lipases, or bioethanol. Transforming industrial strains with pNW33N-GFP allows for continuous tracking, as GFP systematically accumulates within the host cytoplasm proportional to cell division. Investigators can directly monitor active fluorescence intensity at an emission peak of 510 nm via plate readers, eliminating the need for destructive sampling or manual colony counts to track real-time biomass kinetics and live-cell density.

2. High-Throughput Screen of Novel Thermostable Promoters (Promoter Trapping Arrays):By excising the default promoter upstream of the GFP coding matrix, investigators can clone a fragmented genomic DNA library from an extremophilic organism directly into the vacant locus. Following electroporation into Bacillus licheniformis, plates are exposed to a 488 nm blue light or UV transilluminator.Colonies that exhibit intense green fluorescence instantly signal the presence of a robust, highly active thermostable promoter upstream, accelerating the discovery of novel expression tools for synthetic biology.

3. In Vivo Physiological Stress Sensing in Harsh Industrial Environments:Deployed to measure real-time translational efficiency and structural cellular integrity during severe industrial fermentation shocks (e.g., severe osmotic shifts from high substrate concentrations, accumulation of toxic organic byproducts like ethanol, or localized heat shock). Tracking fluctuations in GFP fluorescence intensity and folding kinetics provides insights into the stress-defense mechanics of extremophiles.

III Laboratory E. coli Propagation, High-Voltage Electroporation, and Quantitative Fluorescence Assays

1. Vector Propagation and High-Purity Isolation inside E. coli

• Transformation Sequence: Deliver the circular pNW33N-GFP construct into standard competent E. coli cells (such as DH5$\alpha$ or TOP10) via classic heat-shock parameters. Spread the mixture uniformly onto solid LB agar plates supplemented with 100 $\mu$g/mL Ampicillin and incubate at 37 °C overnight in the dark.

• Liquid Scaling & Quality Validation: Inoculate a verified single colony into selective LB liquid broth and cultivate at 37 °C for 12 - 14 hours. Extract the plasmid using a high-quality purification kit. Because pNW33N operates as a medium-to-low copy shuttle vector, ensure optimal cell mass input to harvest a high concentration ($\ge 200\text{ ng/}\mu\text{L}$) with clean purity parameters ($OD_{260}/OD_{280} = 1.80 - 1.90$).

2. High-Voltage Electroporation of Gram-Positive Thermophilic Strains

Gram-positive bacilli and thermophiles possess a thick, highly cross-linked peptidoglycan cell wall that resists chemical transfection.High-voltage electroporation is required to introduce foreign DNA into these hosts.

1. Preparation of Electrocompetent Cells (e.g., Geobacillus stearothermophilus):

   • Inoculate the target strain into a nutrient-rich media matrix (such as TBY broth) and agitate vigorously at its optimal vegetative growth temperature (typically 55 °C - 60 °C) until it hits mid-log phase ($OD_{600} \approx 0.4 - 0.6$).

   • Plunge the culture flask immediately into an ice-water slurry and chill statically for 30 minutes to rapidly arrest cellular division.

   • Harvest the biomass via cold centrifugation at 4 °C. Wash the pellet 3 - 4 times with ice-cold, non-conductive Hyperosmotic Wash Buffer (Formulation: 0.5 M Sucrose, 10% Glycerol, 1 mM $MgCl_2$) to strip out electrolyte ions that could cause electrical arcing. Resuspend the final pellet in a minimal volume of the same hyperosmotic matrix, aliquot, and hold on ice.

2. Executing the High-Voltage Pulse:

   • Combine 60 - 80 $\mu$L of electrocompetent cells with 1 - 2 $\mu$g of concentrated pNW33N-GFP plasmid DNA. Transfer the mixture into a pre-chilled 0.2 cm gap electroporation cuvette and rest on ice for 2 minutes.

   • Insert the cuvette into an electroporator apparatus (e.g., Bio-Rad Gene Pulser) calibrated to the following core parameters:Voltage = 2.0 - 2.5 kV, Capacitance = 25 $\mu\text{F}$, Resistance = 200 - 400 $\Omega$. Discharge the pulse, ensuring the time constant clocks steadily between 4.5 and 5.5 milliseconds.

3. Hyperosmotic Outgrowth Recovery (Critical Quality Step):

   • Within 5 seconds post-discharge, immediately flood the cuvette with 1 mL of recovery broth pre-warmed to 50 °C and enriched with 0.5 M Sucrose to stabilize internal osmotic pressure.

   • Transfer the suspension into a sterile tube and incubate at a moderated recovery temperature (45 °C - 50 °C; lowering the temperature slightly below the vegetative optimum of 60 °C slows metabolic strain, facilitating cell membrane repair) with gentle agitation at 100 rpm for 1.5 - 2 hours.

3. Thermophilic Antibiotic Selection and Quantitative Fluorescence Profiling

1. High-Temperature Selection Gate:Plate the recovered out-growth uniformly onto solid hyperosmotic LB agar plates supplemented with 5 - 10 $\mu$g/mL Chloramphenicol. Invert the plates and place into a high-temperature constant incubator calibrated to 55 °C - 60 °C for 24 - 36 hours in total darkness. Transformed single colonies will emerge as dense, well-defined circular units.

2. Green Fluorescence (GFP) Visualization and Quantitative Measurement:

   • Visual Colony Inspection: Position the developed selection plate directly over a 488 nm blue light box or an automated UV gel documentation station inside a darkroom environment. Transformed colonies expressing the GFP reporter will emit a bright, sharp green-yellow fluorescence visible to the naked eye.

   • Quantitative Liquid Fermentation Profiling (Microplate Assay):Inoculate verified fluorescent single colonies into liquid production medium spiked with 10 $\mu$g/mL Chloramphenicol and agitate at a high temperature of 60 °C. Extract 100 $\mu$L aliquots of the raw fermenting broth at specific target timepoints (e.g., 4h, 8h, 12h, 24h) and transfer directly into black-walled 96-well microplates.Configure the microplate reader to the following optical channels:Excitation Wavelength = 485 - 488 nm, Emission Wavelength = 510 - 515 nm. Record the Relative Fluorescence Units (RFU) alongside the parallel optical density ($OD_{600}$) values for each well. Calculating the final $\text{RFU} / OD_{600}$ ratio normalizes the variations in bacterial cell density across samples, enabling precise quantification of transcription efficiency under extreme thermal stress.

BioVector NTCC质粒载体菌株细胞蛋白抗体基因保藏中心

电话:400-800-2947

工作QQ/微信同号:1843439339

网址http://www.biovector.net