Delayed-onset micrococcus luteus-induced postoperative endophthalmitis several months after cataract surgery:A case report

BACKGROUND Micrococcus luteus(M.luteus)-induced endophthalmitis is very rare and and may present as either acute or chronic postoperative endophthalmitis.The aim of this study was to report a case of delayed-onset M.luteus-induced endophthalmitis that occurred several months after cataract surgery.CASE SUMMARY A 78-year-old man presented with decreased vision,pain and redness in the right eye that had begun 3 days prior.He had undergone cataract surgery 4 mo prior.Visual acuity was counting fingers;slit-lamp examination revealed conjunctival injection,posterior corneal precipitates,anterior chamber inflammation(cell 4+),and hypopyon.Fundus examination revealed moderate vitreous haze.Urgent vitrectomy was performed for suspected infectious endophthalmitis,followed by vitreous irrigation with injections of antibiotics.On the postoperative day 1,anterior chamber cell decreased to 2+and hypopyon was not observed on slit lamp examination.Six days postoperatively,the patient had recurrent eye pain,and the anterior chamber cell grade increased to 4+;hypopyon recurred in the anterior chamber,and whitish plaque was observed in the lens capsule.Therefore,the patient underwent intraocular lens(IOL)and lens capsule removal,followed by vitreous irrigation,antibiotics injection,and vitrectomy.M.luteus was identified from a lens capsule culture.CONCLUSION In cases of delayed-onset M.luteus-induced endophthalmitis,early vitrectomy and removal of the IOL and lens capsule may be necessary.

Cu(Ⅱ)离子在Micrococcus luteus细菌上的吸附机理

采用红外光谱分析法、扫描电子显微镜 X射线能量散射光谱和离子交换实验探讨了Cu(Ⅱ )离子与Micrococcusluteus细菌可能的作用机理 .结果表明 ,Cu(Ⅱ )离子与细菌中常见离子如K+ ,Na+ ,Mg2 + 和Ca2 + 之间存在着离子交换作用 ,但并不是唯一的 ,同时还存在着Cu(Ⅱ )离子与带负电荷细菌表面的静电吸引作用 ,当溶液pH值较高时 ,Cu(Ⅱ )离子又可能形成氢氧化物微沉淀沉积在细胞表面 .

A novel salt-tolerant Micrococcus sp. DUT_AHX capable of degrading nitrobenzene

A novel strain of Micrococcus sp.DUT_AHX,which was isolated from the sludge of a nitrobenzene(NB)-manufacturing plant and could utilize NB as the sole carbon source,was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA(rDNA)sequence analysis.It can grow at the temperature up to 40℃or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani(LB)medium.The optimal degradation conditions are as follows:temperature 37℃,pH 7.0,and shaking speed 150 r/min.The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source.Furthermore,the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1,6-dioxygenase activity.The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.

Purification and Characterization of an Alkaline Protease from Micrococcus sp.Isolated from the South China Sea

Protease is wildly used in various fields,such as food,medicine,washing,leather,cosmetics and other industrial fields.In this study,an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China Sea was purified and characterized.The growth curve and enzyme activity curve indicated that the cell reached a maximum concentration at the 30 th hour and the enzyme activity reached the maximum value at the 36 th hour.The protease was purified with 3 steps involving ammonium sulfate precipitation,ion-exchange chromatography and hydrophobic chromatography with 8.22-fold increase in specific activity and 23.68% increase in the recovery.The molecular mass of the protease was estimated to be 25 k Da by SDS-PAGE analysis.The optimum temperature and p H for the protease activity were 50℃ and pH 10.0,respectively.The protease showed a strong stability in a wide range of pH values ranging from 6.0–11.0,and maintained 90% enzyme activity in strong alkaline environment with p H 11.0.Inhibitor trials indicated that the protease might be serine protease.But it also possessed the characteristic of metalloprotease as it could be strongly inhibited by EDTA and strongly stimulated by Mn^(2+).Evaluation of matrix-assisted laser desorption ionization/time-of-flight MS(MALDI-TOF-TOF/MS) showed that the protease might belong to the peptidase S8 family.

Isolation, characterization and chromatography based purification of antibacterial compound isolated from rare endophytic actinomycetes Micrococcus yunnanensis

Endophytic actinomycetes are considered as one of the relatively unexplored potential sources in search of antibiotic producer against antibiotic resistant pathogens. A potent strain isolated from Catharanthus roseus that displays antibacterial potential against antibiotic resistant human pathogen Staphylococcus aureus was characterized and designated as Micrococcus yunnanensis strain rsk5. Rsk5 is capable of producing optimum antibacterial metabolites on starch casein medium at 30 °C, p H 5 and 2% Na Cl condition. The crude antibacterial agent was extracted from fermentation broth by ethyl acetate and separated by TLC using chloroform-methanol(24:1, v/v) solvent system with R f value of 0.26. It was partially purified by flash chromatography, followed by HPLC and analyzed by ultraviolet visible spectrophotometer to get absorption maxima at 208.4 nm. The ESI-MS spectra showed molecular ion peaks at m/z 472.4 [M-H], which does not match with any known antibacterial compound.

New Strains of Arthrobacter and Micrococcus Producing Lysine from Hydrocarbon

Following the bioautographic te-chnique, 24 lysine producing microor-ganisms have been isolated from amongthe 263 hydrocarbon utilisers. Morphological, cultural and biochemicalcharacters of two promising isolates,have been studied. One of them iden-tified as Arthrobacter globiformis andthe other as Micrococcus varians, pro-duce 3.4 and 2.6 g lysine per litreof medium.

Regulation of glucose and protein syntheses by Micrococcus luteus during the fermentation of a Nigerian rice, <i>Oryza sativa</i>variety “Igbimo”

Micrococcus luteus synthesises glucose and protein during the fermentation of a Nigerian rice. To regulate the formation of these substances, mutation was carried out with an alkylating agent: ethylmethyl sulphonate (EMS). Screening the mutants generated for the levels of the traits expressed, four major groups were obtained. These are poor, moderate, good and super producers of either glucose or protein. They produced the properties at 0 - 1.00, 1.01 to 1.99 (moderate) and 2.0 to 2.99 (good) and 3.0 and above (super) mg.mL–1 of each substance. The classes were made up of 37, 40, 20 and 3 mutants for glucose production and 13, 35, 40 and 12 mutants for protein synthesis. The wild strain bacterium made 0.86 mg.mL–1 glucose and 1.2 mg.mL–1 protein describing the M. luteus as poor glucose maker and moderate protein producer. It was also noticed that the mutation caused some variants (25%) to form more glucose than protein;the remaining 75% of the population are made up of two sets viz: mutants having better ability to synthesise protein at higher concentrations than glucose and those that formed about the same amounts of the substances. It thus follows that the glucose and protein productions in M. luteus are genetically based and can be regulated by genetic manipulation.

Screening of Soil Antagonistic Bacteria for Watermelon Fusarium Wilt

[Objective] The aim of this study was to screen bacteria strains with stable antagonistic effect against watermelon fusarium wilt from soil and investigate the biological control of watermelon fusarium wilt by applying the antagonistic bacteria strains into soil.[Method] Actinomycete strains,fluorescent bacteria strains and bacillus strains were isolated from soil samples by the dilution-plate method,then its resistance was screened respectively by the improved confront culture method after colonies were purified.Finally,bacteria strains with better antagonistic effect were identified.[Result] 29 bacteria strains with stable antagonistic effect against watermelon fusarium wilt were screened from 39 soil samples,which contained 15 fluorescent bacteria strains,5 bacillus strains and 9 actinomycete strains.Furthermore,three antagonistic bacteria strains of FM2,FM3 and FM4 with the strongest antagonism were identified primarily.[Conclusion] According to cultural characteristics,morphological observation,biochemical and physiological tests,FM2 belongs to bacillus subtilis,while FM3 and FM4 belong to micrococcus.

家蝇幼虫抗菌物质的热稳定性研究

为探讨家蝇(Musca domestica)幼虫抗菌物质的热稳定性,于针刺家蝇3龄幼虫48 h后提取血淋巴,经不同时间不同温度加热处理,测定其对溶壁微球菌(Micrococcus lysodeikticus)和金黄色葡萄球菌(Staphylococcus aureus)的抑制效果。结果表明,家蝇幼虫经针刺诱导产生的抗菌物质对高温具有一定耐受性,处理温度为80～100℃时抑菌活力随处理时间延长而减弱,60℃处理30 s至10 min对其抑菌活力无明显影响。

丝光绿蝇幼虫血淋巴中抗菌物质的抑菌活性

观察丝光绿蝇(Lucilia sericata)三龄幼虫经针刺体壁诱导48 h后的血淋巴在不同pH琼脂平板上对溶壁微球菌(Micrococcus lysodeikticus)和金黄色葡萄球菌(Staphylococcus aureus)的抑菌效果,以及经不同pH缓冲液处理后对溶壁微球菌的抑菌效果。结果表明,丝光绿蝇幼虫经针刺诱导后48 h的血淋巴在pH 6.0、6.5的琼脂平板上对金黄色葡萄球菌的抑菌环较大较清晰,随pH增加抑菌环直径减小。在pH 6.0时,对溶壁微球菌的抑菌环直径最大,随pH增加抑菌环直径减小。用pH 6.0的缓冲液稀释处理血淋巴时,对溶壁微球菌的抑菌环最大,用pH 9.0缓冲液稀释后对溶壁微球菌的抑菌环最小。说明丝光绿蝇幼虫经针刺体壁诱导产生的抗菌物质在酸性条件下比在碱性条件下具有更强的抑菌活性。

Bacteriocin from Bacillus subtilis as a novel drug against diabetic foot ulcer bacterial pathogens

Objective:To isolate and identify Bacillus subtilis(B.subtilis)from soil and to characterize and partially purify the bacteriocin.To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens.Methods:Genotypic identification was done based on Sergey's manual of systemic bacteriology.Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method.Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain.Further identification was done by 16S rRNA sequencing.Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method.The strain was identified to produce bacteriocin by stab overlay assay.Bacteriocin was extracted by organic solvent extraction using chloroform,further purified by HPI.C and physical,and chemical characterization was performed.Results:The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin.HPLC purification revealed that the extracts are bacteriocin.The phylogenetic tree analysis results showed that the isolate was 99%related to B.subtilis BSF01.The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp.Conclusions:Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens,which can thus be applied as a better drug molecule on further studies.The strain B.subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens.

A rapid and accurate 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay for quantification of bacteriocins with nisin as an example

The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.

Characterization and Functional Study on Octopus ocellatus Interleukin-17

Interleukin-17(IL-17),a prototype member of IL-17 family,plays an important role in defending against extracellular pathogens as a pro-inflammatory cytokine.The function and distribution of IL-17 have been extensively studied in many vertebrates.However,few study has focused on the role of IL-17 in invertebrates,especially in mollusks.In this study,an IL-17 homolog was identified in Octopus ocellatus,which was designated as OoIL-17.The phylogenetic analysis showed that OoIL-17 is clustered well with other invertebrate IL-17,indicating it is highly similar with the IL-17 of other invertebrates.The expression of OoIL-17 gene was analyzed with qRT-PCR in a variety of healthy tissues and the hemocytes infected with Vibro anguillarum or Micrococcus luteus.The mRNA of OoIL-17 gene is constitutively expressed at different levels in all examined tissues of healthy O.ocellatus,including mantle,stomach,hemocytes,muscle,gonad,hepatopancreas,systemic heart and gill.The lowest expression was observed in mantle while the highest was observed in hepatopancreas.The expression level of OoIL-17 gene is significantly up-regulated in O.ocellatus hemocytes upon infection with V.anguillarum and M.luteus,indicating its active involvement in the host immune response against bacterial pathogens.The results laid the foundation for further understanding the innate immune mechanisms of IL-17 in O.ocellatus and mollusks.

化工上的应用

901121 微球菌菌株RCO-4M对侧链具有偶数碳原子的n-烷基环已烷的代谢[英] /Yoshizako, F.…∥J. Fermn. Bioeng.-1989, 67(05).-335～338[译自 CBA,1989,(10),4416] 这种环己烷的侧链中碳原子数为6、8、10、12和14。在这项利用微球菌(Micrococcus)菌株RCO-4M进行的研究中,提出了通过菌对这种环己烷的代谢,产生环已烷羧酸、环已烷乙酸、1-环已烷羧酸、6-羧基已酸、已二酸和反-4-羧基环已烷乙酸的证据。(郭殿瑞)

南极微球菌产低温淀粉酶条件优化及酶学性质初步研究

采用单因素试验对南极微球菌（Micrococcus antarcticus）产低温淀粉酶的条件进行了初步优化,其发酵培养基组成为（g/L）：Na2HPO42.0,KH2PO41.0,MgSO4.7H2O 0.1,NaCl 5.0,（NH4）2SO42.5,麦芽糖5.0,微量元素溶液5.0 mL,pH 8.0,500 mL三角瓶装液100 mL,12℃,160 r/min振荡培养64 h,在此条件下,发酵液酶活由优化前的0.24 U/mL提高到2.6 U/mL,是优化前的10.8倍.发酵液经Millipore超滤膜包浓缩、Hitrap Q阴离子交换层析、Superdex 200凝胶过滤层析纯化获得纯淀粉酶.该淀粉酶的最适作用温度为30℃,在10-15℃下仍具有较高活性,但对热敏感,属典型的低温酶;最适作用pH为6.0,在pH 6.0-10.0范围内较稳定（〉70%）;Ca^2＋、Mn^2＋、Co^2＋、Mg^2＋对该酶有较为明显的激活作用,而Zn^2＋、Ba^2＋、Ag^＋、Cu^2＋、Al^3＋、Fe^2＋、Fe^3＋、Hg^2＋、螯合剂EDTA、citrate则对该酶有不同程度的抑制作用,并且在Tween系列及TrintonX-100等非离子型表面活性剂中表现出较好的稳定性;酶的动力学参数Km为0.90 mg/mL.

Relationship between Intrauterine Bacterial Infection and Early Embryonic Developmental Arrest

Background： Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest. Methods： Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion （control group） and from 45 patients who displayed early embryonic developmental arrest （trial group）. Results： Intrauterine bacterial infection was discovered in both groups. The infection rate was 24.44% （11/45） in the early embryonic developmental arrest group and 9.09% （3/33） in the artificial abortion group. Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% （6/45）, and none was detected in the artificial abortion group. M. luteus infection was significantly different between the groups （P 〈 0.05 as shown by Fisher＇s exact test）. In addition, no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest. Conelusions： IV/. luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.

Affinity Switching for Lysozyme and Dual-responsive Microgels by Stopped-flow Technique： Kinetic Control and Activity Evaluation

The use of proteins as therapeutics in nanomedicine is an emerging research field and has developed rapidly.However,proteins are always vulnerable to renal excretion or digestion by the proteolytic system in vivo,which limits their usage to a large extent.Although biocompatible polymers have been covalently linked to proteins to protect them from recognition by the immune system and prolong their circulation time,the biological activity of them is sometimes decreased.To fill this gap,physical isolation,wrapping,or encapsulation techniques are employed.Up to now,various mature examples were reported,but the whole time scales for guest molecules loading and releasing,especially the initial rapid loading process,were rarely mentioned.Herein,a series of dual-responsive poly（N-isopropylacrylamide-co-methacrylic acid）（P（NIPAM-co-MAA）） microgels were synthesized and employed to investigate the kinetics of in situ complexation and release of lysozyme under external stimuli modulation upon a stopped-flow apparatus,which was suitable for rapid dynamic monitoring.Close inspection of the adsorption kinetics during the early stages（〈 50 s） revealed that the initial microgel collapse occurred within ~1 s,with more rapid transitions being observed when higher lysozyme concentrations were targeted.All the dynamic traces could be well fitted with a double exponential function,suggesting a fast（τ1） and a slow（τ2） relaxation time,respectively.Then,the kinetics of releasing bound lysozyme from microgels was carried on by utilizing the p H-responsive property,and the evaluation of the activity of released lysozyme was synchronously measured in a Micrococcus lysodeikticus（M.lysodeikticus） cell suspension.The corresponding relaxation time（τ） was also calculated by fitting the recorded dynamic traces.We speculate that this work can provide basic dynamics data and theoretical basis for microgels based nanocarriers to be used for protein delivery,controlled release,and possible chemical separation.