The natural course of bacillus Calmette-Guerin induced bladder lesions:A long-term follow-up study and systematic review

Objective:Bacillus Calmette-Gue´rin(BCG)instillation is the standard adjuvant treatment for intermediate-and high-risk non-muscle-invasive bladder cancer after transurethral resection.Nevertheless,its toxicity often causes bladder complications.On follow-up cystoscopy,post-BCG bladder lesions can be pathologically benign,urothelial carcinoma recurrence,or other types of bladder malignancy.Only a small number of case reports have been published on post-BCG bladder lesions.Their clinical features,natural course,and management remain unknown.Methods:We retrospectively studied cystoscopic videos and medical records of BCG-treated bladder cancer patients at our center.During a long-term follow-up,we took biopsies on tumor-like lesions and described their changes.In addition,we summarized previous studies on post-BCG bladder lesions by systematic literature searching and review.Results:We described a series of three cases with post-BCG bladder lesions mimicking tumor recurrence from a total of 38 cases with follow-up data for more than 5 years.Those lesions could last,grow,or disappear spontaneously,and remain pathological benign for years.In systematic review,we identified and analyzed a total of 15 cases with post-BCG bladder lesions with detailed clinical information.Eleven of the 15 were benign and have a good prognosis with nephrogenic adenoma being the most common pathological type.Conclusion:Based on previous studies and our experience,benign lesions after BCG instillation cannot distinguish with cancer recurrence by cystoscopy alone,even under narrow band imaging mode.Nonetheless,given most of them have a good prognosis,random biopsy or transurethral resection might be spared in the patients with long-term negative biopsy and urine cytology.

Intravesical bacillus Calmette-Guerin(BCG)in treating non-muscle invasive bladder cancer—analysis of adverse effects and effectiveness of two strains of BCG(Danish 1331 and Moscow-I)

Objective:To compare the differences in adverse effects and efficacy profile between bacillus Calmette-Guerin(BCG)Danish 1331 and BCG Moscow-I strain in management of non-muscle invasive bladder cancer.Methods:Clinical data of 188 cases of non-muscle invasive bladder cancer treated with BCG between January 2008 and December 2018 in our institute were collected prospectively and analysed retrospectively,and 114 patients who completed a minimum of 12 months of follow-up were analysed.Patient and tumor characteristics,strain of BCG,adverse effects,and tumor progression were included for analysis.Intravesical BCG was instilled in intermediate-and high-risk patients.Six weeks of induction BCG,followed by three weekly maintenance BCG at 3,6,12,18,and 24 months was advised in high-risk patients.Results:Overall 68 patients received BCG Danish 1331 strain and 46 patients received Moscow-I strain.Patient and tumor characteristics were well balanced between the two groups.The median follow-up period was 42.5 months and 34.5 months in Danish 1331 and Moscow-I groups,respectively.Adverse events like dropout rate,antitubercular treatment requirement,and need of cystectomy were higher in Moscow-I group(n=31,67.4%)when compared to Danish 1331 strain(n=33,48.5%)(p=0.046).On direct comparison between Danish 1331 and Moscow-I strain,there was similar 3-year recurrence-free survival(80.0%vs.72.9%)and 3-year progression-free survival(96.5%vs.97.8%).Conclusion:Study results suggest no significant differences between Danish 1331 and Moscow-I strain in recurrence-free survival and progression-free survival,but a significantly higher incidence of moderate to severe adverse events in BCG Moscow-I strain.

Empirical Assessment of Bacillus Calmette-Guérin Vaccine to Combat COVID-19

COVID-19 has become one of the critical health issues globally,which surfaced first in latter part of the year 2019.It is the topmost concern for many nations’governments as the contagious virus started mushrooming over adjacent regions of infected areas.In 1980,a vaccine called Bacillus Calmette-Guérin(BCG)was introduced for preventing tuberculosis and lung cancer.Countries that have made the BCG vaccine mandatory have witnessed a lesser COVID-19 fatality rate than the countries that have not made it compulsory.This paper’s initial research shows that the countries with a longtermcompulsory BCGvaccination system are less affected by COVID-19 than those without a BCG vaccination system.This paper discusses analytical data patterns for medical applications regarding COVID-19 impact on countries with mandatory BCG status on fatality rates.The paper has tackled numerous analytical challenges to realize the full potential of heterogeneous data.An analogy is drawn to demonstrate how other factors can affect fatality and infection rates other than BCG vaccination only,such as age groups affected,other diseases,and stringency index.The data of Spain,Portugal,and Germany have been taken for a case study of BCG impact analysis.

Multi-organ failure with atypical liver granulomas following intravesical Bacillus Calmette-Guerin instillation

Bacillus Calmette-Guerin(BCG) intravesical instillation has been adopted in the treatment of patients with superficial bladder cancer.BCG-induced disseminated infection,though rare,has been associated with the histological finding of epithelioid granulomas in different organs,including the liver.We report the case of an adult patient with multi-organ failure,who developed sepsis,acute respiratory failure and acute hepatic failure with encephalopathy whose liver biopsy confirmed the presence of atypical,granulomatous-like lesions.Recovery was observed only after empirical therapy for Mycobacterium bovis with isoniazid,rifampicin,ethambutol and steroids was introduced.This case highlights the importance of a thorough patient assessment in order to exclude other more common causes of hepatic granulomas and to confirm diagnosis.Histological findings may be non-specific when the liver is involved in BCGinduced disseminated infection.

The Effects of <i>Ganoderma lucidum</i>on Initial Events Related to the <i>Bacillus Calmette-Guérin</i>Efficacy and Toxicity on High-Risk Uroepithelial Cells: An <i>in Vitro</i>Preliminary Study

A novel prophylactic regimen is demanded for preventing bladder cancer recurrence, because of the high side-effect tolls of conventional adjuvant Bacillus Calmette-Guérin (BCG) immunotherapy, in addition to its only moderate efficacy. In vitro and animal studies have demonstrated the anti-cancer properties of a medicinal mushroom called Ganoderma lucidum (GL). In this study, a pre-malignant human uroepithelial cells (HUC-PC) model was utilized to compare the effectiveness between ethanol extract of GL (GLe) and BCG on interleukin-6 (IL-6) secretion and lactate dehydrogenase (LDH) cytotoxicity. Additionally, parameters relevant to the BCG efficacy and safety, including free soluble fibronectin (FN) and cell-surface glycosaminoglycans (GAGs) levels were tested, following the exposure of GLe to the cells. GLe at 100 μg/ml and BCG at 4.8 × 107 CFU were shown to induce equivalent levels of IL-6, suggesting the potential synergism, while the tested concentrations of GLe were non-cytotoxic. During the initial four hours of GLe exposure, the free FN concentrations in harvested media were significantly reduced that might facilitate the binding of BCG for uroepithelial internalization to enhance BCG efficacy. Furthermore, the cell membrane-bound GAGs levels of HUC-PC cells were significant increased in response to GLe to suggest cellular protection from BCG infection. In summary, current findings suggest the potential additive synergism of GLe with the BCG efficacy, as well as its protective effects, and thus reducing the BCG toxicity.

Nano-Bacillus Calmette-Guérin immunotherapies for improved bladder cancer treatment

Cancer immunotherapy has rapidly become the fourth mainstream treatment alternative after surgery,radiotherapy,and chemotherapy,with some promising results.It aims to kill tumor cells by mobilizing or stimulating cytotoxic immune cells.However,the clinical applications of tumor immunotherapies are limited owing to a lack of adequate delivery pathways and high toxicity.Recently,nanomaterials and genetic engineering have shown great potential in overcoming these limitations by protecting the delivery of antigens,activating targeted T cells,modulating the immunosuppressive tumor microenvironment,and improving the treatment efficacy.bacillus Calmette-Gué;rin(BCG)is a live attenuated Mycobacterium bovis vaccine used to prevent tuberculosis,which was first reported to have antitumor activity in 1927.BCG therapy can activate the immune system by inducing various cytokines and chemokines,and its specific immune and inflammatory responses exert antitumor effects.BCG was first used during the 1970s as an intravesical treatment agent for bladder cancer,which effectively improved immune antitumor activity and prevented tumor recurrence.More recently,nano-BCG and genetically engineered BCG have been proposed as treatment alternatives for bladder cancer due to their ability to induce stronger and more stable immune responses.In this study,we outline the development of nano-BCG and genetically engineered BCG for bladder cancer immunotherapy and review their potential and associated challenges.

基于转录组学分析揭示蜡样芽胞杆菌(Bacillus cereus)AR1002阻控黄曲霉生长的生理机制研究

黄曲霉(Aspergillus flavus)极易侵染油料等农产品,其次级代谢产物黄曲霉毒素严重危害人体健康,阻控黄曲霉污染已成为亟待解决的国际难题。为探明蜡样芽胞杆菌(Bacillus cereus)AR1002抑制黄曲霉生长、阻控黄曲霉污染的生理及分子机制。该研究采用AR1002代谢产物对黄曲霉进行处理,并对黄曲霉生长及产孢表型进行鉴定,通过显微结构及转录组学分析,对AR1002的抑菌机制进行了初探。蜡样芽胞杆菌AR1002代谢物可抑制黄曲霉菌丝生长、干物质积累分别达24.73%,65.00%,减少孢子数量达98.80%;AR1002通过抑制glpA和AYR1等关键基因表达调控黄曲霉甘油磷酸代谢,通过抑制SEC61A、RAD23、ATP13A1、UBE2G2等关键基因的表达调控内质网中蛋白质加工;此外,AR1002代谢产物通过下调RAD51和RAD54B等DNA修复机制相关基因,抑制黄曲霉同源重组及非同源性末端连接过程,最终达到抑制黄曲霉生长及产孢的目的。上述结果表明,蜡样芽胞杆菌(Bacillus cereus)AR1002有望应用于实际生产中以应对黄曲霉污染问题。

南瓜白粉病拮抗内生细菌Bacillus cereus B4-2的分离鉴定及生防效果

从高抗白粉病的南瓜植株内分离筛选出对南瓜白粉病有较好防治效果的内生拮抗细菌菌株,为南瓜白粉病的生物防治提供新途径。采用孢子萌发抑制法、叶盘漂浮法和温室盆栽试验筛选出有较好防效的内生细菌,用形态观察、生理生化测定和分子生物学方法进行鉴定。结果表明,从高抗白粉病的南瓜自交系22G3植株内分离获得29株内生拮抗细菌菌株,5个菌株对南瓜白粉菌的孢子萌发抑制率在50%以上,其中菌株B4-2对白粉菌的孢子萌发抑制率最高,为88.65%。叶盘和室内盆栽试验结果均表明,菌株B4-2对南瓜白粉病的防治效果最好,防治效果分别达79.58%和83.21%。不同稀释倍数的B4-2发酵液对南瓜白粉病均有一定的防治效果,随着稀释倍数的增大,防治效果降低,其中菌株B4-2发酵液原液对南瓜白粉病的防治效果最好,达82.14%。通过形态特征、生理生化特征及基因序列分析,鉴定菌株B4-2为蜡样芽孢杆菌(Bacillus cereus)。综上所述,蜡样芽孢杆菌B4-2能较好地防治南瓜白粉病,有一定的开发潜力。

蚯蚓联合生防细菌Bacillus velezensis改善连作百合土壤细菌群落结构及防治枯萎病的效果

【目的】从土壤理化性状和微生物群落结构及多样性角度,研究蚯蚓联合生防细菌改善百合连作障碍的机理和效果,为湖南百合产业化种植提供技术措施。【方法】采用盆栽试验方法,在湖南长沙连续种植了两季百合(Lilium lancifolium Thunb.)。供试土壤为红壤,生防菌为Bacillales velezensis YFB3-1菌液(菌体浓度为10^(9) CFU/mL),蚯蚓为赤子爱胜蚓(Eisenia fetida)。试验设单施菌液(T1)、只接种蚯蚓(T2)、同时使用菌液和蚯蚓(T3) 3个处理,以不使用菌剂和蚯蚓为对照(CK)。调查了两茬百合产量和枯萎病病情指数,分析了第二茬百合根际土壤理化性质、细菌群落结构和多样性,以及连作百合产量与根际土壤理化性质、细菌群落和枯萎病的相关性。【结果】与第一茬相比,同一处理的第二茬百合产量都显著下降。两年连作百合产量都以同时使用菌液和蚯蚓(T3)处理为最高,分别为16464、15674 kg/hm^(2),都显著高于同年份其他处理。两年连作百合枯萎病发病率和病情指数都以T3为最低,都显著低于同年份其他处理,T3处理百合枯萎病病情指数分别为18.15(2019年)、25.00 (2020年),并且两年的防治效果(T3)都明显优于单施菌液(T1)和接种蚯蚓(T2)。相比于对照(CK),2019、2020年T3处理百合枯萎病防治效果分别为44.55%、37.66%,分别增产15.05%、14.78%。蚯蚓联合生防菌YFB3-1增加了根际土壤Rhizobiales、Flavobacteriales、Pseudomonadales、Bacillales等有益微生物的种群丰度,蚯蚓与生防菌YFB3-1在抑制连作百合枯萎病方面具有显著的互作效应,因而缓解连作百合产量下降的效果最佳。【结论】在施用芽孢杆菌生防菌剂防治连作百合枯萎病的同时,可以增施有机肥(牛粪)来提高土壤中蚯蚓数量,有效预防百合枯萎病发生,减少连作百合产量损失。

莫海威芽孢杆菌(Bacillus mojavensis)ZLX10对发酵雪茄烟叶中性致香成分的影响

为探究烟草源微生物单菌发酵对雪茄烟叶挥发性致香成分的影响,采用GC-MS检测莫海威芽孢杆菌(Bacillus mojavensis)ZLX10发酵雪茄烟叶中性致香成分,筛选差异致香成分,并与感官评价进行相关性分析,结合ROAV值变化,明确ZLX10提升雪茄烟叶感官品质的关键致香成分。结果表明,ZLX10发酵雪茄烟叶后,香气总量和大多数中性致香成分含量均显著提高,共筛选得到15种差异中性致香成分,共有10种致香成分显著上调(P<0.05),其中巨豆三烯酮A、巨豆三烯酮B、6-甲基-5-庚烯-2-酮、2,6,6-三甲基-2-环己烯-1,4-二酮、茄酮和植物醇与烟叶香气呈显著正相关(P<0.05),可认为是增加烟叶干香和花香的关键差异致香成分;共有5种致香成分显著下调(P<0.05),其中苯乙醛和2,4-二叔丁基-6-硝基苯酚与烟叶刺激性呈显著正相关(P<0.05),对烟叶香气有较大的负面影响。由此可知,ZLX10发酵能促进雪茄烟叶香气质和香气量得到提升,这为人工接菌发酵雪茄烟叶提供了基础。

1株抗真菌贝莱斯芽孢杆菌(Bacillus velezensis)lut-Y1的鉴定及抑菌活性研究

【目的】探究1株来自枸杞果实的贝莱斯芽孢杆菌lut-Y1的生长特性及抑菌活性,为微生态制剂的开发和应用提供参考。【方法】通过形态观察和16S rDNA基因测序分析对该菌株进行鉴定;测定该菌株生长曲线及最适pH、碳源、氮源及盐耐受度;采用平板对峙法观察该菌株对链格孢菌(Alternaria alternate)、小麦根腐离蠕孢(Bipolaris sorokiniana)和小孢壳二孢(Ascochyta leptospora)的颉颃作用,并分析该菌株发酵液对3种病原真菌的抑菌活性。【结果】lut-Y1菌株在LB、NA和PDA培养基上均生长良好。根据形态和16S rDNA基因序列特征将lut-Y1菌株鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。在LB液体培养基中,lut-Y1菌株在0~3 h为迟滞期,3~18 h为对数期,18~62 h为稳定期,62 h后进入衰亡期;最适pH为7.0,最适碳源和氮源分别为蔗糖和蛋白胨,对NaCl的耐受量不超过2.0 g/L。lut-Y1菌株对链格孢菌有明显的颉颃作用,对小麦根腐离蠕孢和小孢壳二孢的颉颃作用较弱。对峙平板的两菌交界处,链格孢菌基内菌丝细弱、弯曲;小麦根腐离蠕孢基内菌丝细胞壁被破坏,有泡状突起。发酵液添加量为25%时生长圈直径分别缩小72.80%和83.24%。【结论】贝莱斯芽孢杆菌lut-Y1具有较好的抑菌活性,可为开发以芽孢杆菌为主要活性成分的微生态制剂提供材料。

不同有机废弃物载体对Bacillus megaterium有效性的影响

为了给Bacillus megaterium选择理想的吸附载体。测定了草炭、金针菇渣、腐熟鸡粪、牛粪、羊粪的吸菌量及其载体菌剂的有效活菌数、胞外多糖(EPS)含量和发芽指数。草炭的吸菌量最高为1.64 mL/g,但随存放时间延长,草炭载体菌剂的有效活菌数和EPS含量急剧降低,且38 d内的发芽指数均小于80%,表现植物毒性。鸡粪和金针菇渣的吸菌量虽小于草炭,但随存放时间延长,鸡粪载体菌剂的有效活菌数和EPS含量逐渐增大,金针菇渣载体菌剂的EPS含量逐渐增加、有效活菌数降低幅度缓慢,且存放7 d后发芽指数均大于80%,表现植物无毒性。第38天时鸡粪和金针菇渣载体菌剂的有效活菌数分别为1.29×10^(9)CFU/g和6.20×10^(8)CFU/g,EPS含量分别为535.29 mg/kg和559.34 mg/kg,均显著高于其他载体菌剂。鸡粪和金针菇渣是B.megaterium较为理想的吸附载体。

Mn^(2+)促进Bacillus altitudinis LZP02生物膜形成

【目的】Bacillus altitudinis LZP02是一株水稻根际促生菌(PGPR),能定殖于水稻根部,形成生物膜,且Mn^(2+)对LZP02菌株生物膜形成具有促进作用,但调控机制尚不明确,旨在探究Mn^(2+)对LZP02菌株生物膜形成的促进机制。【方法】采用结晶紫染色法进行生物膜定量分析、蒽酮-硫酸法测定胞外多糖产量、扫描电镜(SEM)观察LZP02菌株在水稻根际定殖情况、转录组学测序技术分析差异表达基因(DEGs)。【结果】添加4 mmol/L Mn^(2+)和8 mmol/L Mn^(2+)显著提高了LZP02菌株的成膜能力和胞外多糖产量,扫描电镜发现4 mmol/L Mn^(2+)和8 mmol/L Mn^(2+)提高了LZP02菌株在水稻根际的定殖能力,随着Mn^(2+)浓度的增加,DEGs数量显著增多,其主要富集在芽孢形成、毒素代谢途径和双组分系统中。1 mmol/L Mn^(2+)和4 mmol/L Mn^(2+)处理组发现skf操纵子中基因的表达均上调。扫描电镜观察发现在1 mmol/L Mn^(2+)和4 mmol/L Mn^(2+)处理组中LZP02菌体存在损伤。4 mmol/L Mn^(2+)处理组双组分系统中KinE和Spo0A基因均显著上调。【结论】Mn^(2+)通过“嗜食同类”和双组分系统中KinE基因激活Spo0A~P提高了菌株LZP02的成膜能力。

Effects of Bacillus Calmette-Guerin on immunometabolism,microbiome and liver diseases

Metabolic diseases have overtaken infectious diseases as the most serious public health issue and economic burden in most countries.Moreover,metabolic diseases increase the risk of having infectious diseases.The treatment of metabolic disease may require a long-term strategy of taking multiple medications,which can be costly and have side effects.Attempts to expand the therapeutic use of vaccination to prevent or treat metabolic diseases have attracted significant interest.A growing body of evidence indicates that Bacillus Calmette-Guerin(BCG)offers protection against non-infectious diseases.The non-specific effects of BCG occur likely due to the induction of trained immunity.In this regard,understanding how BCG influences the development of chronic metabolic health including liver diseases would be important.This review focuses on research on BCG,the constellation of disorders associated with metabolic health issues including liver diseases and diabetes as well as how BCG affects the gut microbiome,immunity,and metabolism.

纳豆芽孢杆菌Bacillus natto NK4液态发酵产纳豆激酶的工艺优化

为提高纳豆激酶的产量,采用单因素试验及正交试验对纳豆芽孢杆菌Bacillus natto NK4进行发酵条件优化,获得该菌种液体发酵产酶的最优条件。结果表明,纳豆芽孢杆菌产纳豆激酶最佳的发酵条件为接种量2%,培养基初始pH值6.0,培养温度34℃,发酵时间72 h。此时,纳豆激酶酶活力由848.28 IU/mL提高到1569.31 IU/mL。

生物炭载Bacillus subtilis菌粒对连作芹菜生长的影响

为解决土壤连作障碍对蔬菜生长发育的不利影响,本研究以连作3年的芹菜土壤为研究对象,采用随机区组试验,设置5种处理:单独施加生物炭(BC)、单独施加Bacillus subtilis菌剂(BS)、生物炭与菌剂混合施加(BB)、施加生物炭载B.subtilis菌粒(BP)、不施加生物炭与菌剂(CK),盆栽种植芹菜,测定其生长与品质指标,探究生物炭和B.subtilis对连作芹菜生长的影响。结果表明,BB、BP处理组芹菜的生长和品质指标都高于其他土壤处理组,BP处理组的芹菜鲜质量、可溶性蛋白含量以及纤维素含量均显著高于BB处理组,分别为60.25 g/棵、27.25 mg/g、2.48%,其他指标两处理间无显著差异。不同土壤处理组芹菜的生长和品质指标都高于CK处理,其中BP处理组各指标值最高,尤其是芹菜鲜质量,增幅高达226.56%。因此,施加生物炭载B.subtilis菌粒提高了连作芹菜生长指标与品质,为农业生产上缓解蔬菜连作障碍奠定了理论基础。

Bacillus globisporus N75 6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达

6-α-葡萄糖基转移酶具有催化α-1,4-葡聚糖的外切水解和转糖基化功能,可通过转糖基活性产生非还原端连有α-1,6键的α-葡聚糖,可用于生产环交替糖及其分支衍生物和环异麦芽寡糖等新型功能糖。为了更好地将6-α-葡萄糖基转移酶应用于食品领域,该研究对来源于Bacillus globisporus N75的6-α-葡萄糖基转移酶在食品安全级菌株枯草芽孢杆菌中进行重组表达,并通过表达宿主的选择及优化发酵条件进一步提高重组蛋白产量。结果表明,宿主WHS9更有利于6-α-葡萄糖基转移酶的重组表达,在20℃的发酵条件下,胞内外可溶性总酶活力可达2.11 U/mL;在25℃添加20 mmol/L海藻糖发酵48 h后,总酶活力可达到2.21 U/mL;优化发酵时间后,发酵36 h总酶活力可达3.14 U/mL,是优化前WHS9表达酶活力的196倍。该研究首次实现了6-α-葡萄糖基转移酶在枯草芽孢杆菌中的重组表达。

李氏禾内生细菌Bacillus cereus J01吸附Cr^(3+)的研究

为考察李氏禾内生细菌蜡样芽孢杆菌Bacillus cereus J01菌株吸附Cr^(3+)的性能,以蜡样芽孢杆菌Bacillus cereus J01失活菌体作为生物吸附剂,采用单因素实验方法考察pH、温度、Cr^(3+)初始浓度、吸附剂用量、吸附时间等条件对Cr^(3+)吸附性能的影响,分析其等温吸附过程、动力学过程及热力学过程,并采用红外光谱方法对吸附机理进行初步分析。结果表明:(1)在50 mL反应体系中,当pH值为6、温度为40℃、Cr^(3+)初始浓度为150 mg·L^(-1)、吸附剂投加量为0.2 g、吸附时间为12 h时,蜡样芽孢杆菌Bacillus cereus J01失活菌体对Cr^(3+)的吸附性能达到最佳,其平衡吸附量和Cr^(3+)去除率分别为34.30 mg·g^(-1)、91.60%。(2)等温吸附过程分析结果显示,朗格缪尔吸附等温模型能更好地模拟蜡样芽孢杆菌Bacillus cereus J01失活菌体对Cr^(3+)的吸附,其吸附过程更倾向于单分子层吸附。(3)吸附过程动力学分析结果显示,蜡样芽孢杆菌Bacillus cereus J01失活菌体对Cr^(3+)的吸附更符合准二级动力学速率方程。(4)吸附过程热力学分析结果显示,在40℃下,吸附过程的△G、△H和△S分别为-2.609 kJ·mol^(-1)、61.792 kJ·mol^(-1)和206.11 J·mol^(-1),该温度下吸附过程是自发过程。(5)红外光谱分析结果显示,蜡样芽孢杆菌Bacillus cereus J01失活菌体对Cr^(3+)的吸附可能通过细胞成分中的氨基、羟基和羰基起作用。该研究结果表明该菌的失活菌体对Cr^(3+)具有较强的吸附性能,并在铬污染的环境治理中具有较好的应用潜力。

耐低温降解菌Bacillus mobilis10的生物学特性及其对海参养殖水质的净化作用

以分离自沿海土壤中的1株芽孢杆菌10为试验对象,研究其在低温条件下(15℃)的生物学特性,实现该菌剂的中试工程化生产以及在海参养殖中对水质净化的示范应用。该菌株通过形态观察及16S rRNA基因序列分析被鉴定为Bacillus mobilis。15℃,经透明圈法确定该菌株具有蛋白酶活性、淀粉酶活性和纤维素酶活性;发酵56 h蛋白酶活性达到9.05 U/mL;在8%质量分数NaCl条件下仍可以存活。利用海参饵料培养基检测菌株对溶解物的降解能力,试验结果显示,B.mobilis 10接种8 h后对饵料培养基中蛋白的降解率达(36.72±0.53)%,对化学需氧量的清除率达(22.80±0.81)%。中试规模(50 L)发酵制备微生物制剂并以终密度约1.0×10^(4)cfu/mL的菌液泼洒海参池,对水体中B.mobilis 10的活菌数、pH、蛋白质含量及化学需氧量进行为期8 d的动态监测,结果表明,以B.mobilis 10制备的微生物制剂能够显著降低海参养殖水体中蛋白和化学需氧量,起到净化水质的目的。试验结果可为水产生态养殖及微生物制剂的开发提供理论基础和应用示范实例。

矿化细菌Bacillus paramycoides对重金属Pb(Ⅱ)和Cd(Ⅱ)的去除及矿化特性

微生物诱导生物矿化可有效固定重金属离子,被认为是一种重要的重金属污染环境修复工艺,对重金属污染生态修复有重要的现实意义。从贵州黔西北某铅锌矿区周边土壤中分离出一株耐Pb(Ⅱ)和Cd(Ⅱ)菌株GS-2,经形态学特征和16S rRNA鉴定为Bacillus paramycoides,菌株GS-2对Pb(Ⅱ)和Cd(Ⅱ)的耐受分别高达1500和50 mg/L,对250 mg/L Pb(Ⅱ)和5 mg/L Cd(Ⅱ)去除率分别为99.54%和69.04%,对重金属Pb(Ⅱ)和Cd(Ⅱ)(均为25 mg/L)混合去除率分别为99.73%和71.46%。SEM-EDS、FTIR和XRD结果显示,菌株通过表面的羟基、羧基、酰胺基和磷酸基团等官能团将Pb(Ⅱ)和Cd(Ⅱ)诱导矿化成Ca_(2.5)Pb_(7.5)(OH)_(2)(PO_(4))_(6)、Ca_(2.1)Pb_(7.9)Cl_(2)(PO_(4))_(6)、Pb_(3)(PO_(4))_(2)、Pb_(5)(PO_(4))_(3)OH、Pb_(9)(PO_(4))_(6)、Pb_(10)(PO_(4))_(6)(OH)_(2)和Ca_(0.67)Cd_(0.33)CO_(3)等晶体矿物。菌株GS-2具有较好的去除和矿化能力,对环境中Pb(Ⅱ)和Cd(Ⅱ)污染的生物修复具有一定应用潜力。