Effects of dietary phytoestrogen on global myocardial ischemia-reperfusion injury in isolated female rat hearts

We investigated the effects of phytoestrogen on global myocardial ischemia-reperfusion injury in five groups of female rats. A high-phytoestrogen group (HPE) was ovariectomized (Ovx) and fed a diet containing soybean protein and a high-isoflavone soy extract. Another Ovx group of rats was fed the same diet as the HPE group but treated with the estrogen receptor blocker ICI-182,780 (HPE + ICI). A third group of Ovx rats was fed a diet containing soybean protein alone (low-phytoestrogen content; LPE). A fourth Ovx group was fed a diet free of phytoestrogen (Ovx). The fifth group of rats was sham ovariectomized (sham). Hearts from all rats were subjected to 30 min of global, hypothermic (4 degrees C), cardioplegic ischemia and 120 min of normothermic (37 degrees C) reperfusion with oxygenated Krebs-Henseleit buffer. Compared with either the sham or the HPE group, the Ovx and HPE + ICI groups had significantly decreased first derivative of left ventricular pressure (dP/dt), coronary flow rate (CFR), nitrite production and mitochondrial respiratory function and significantly increased Ca2+ accumulation and myocardial histological and ultrastructural injury. The CFR of the LPE group was significantly different from that of either Ovx or HPE + ICI group but the dP/dt, nitrite production, Ca2+ accumulation, and mitochondrial function were not. Our results indicate that diets containing phytoestrogen extract play a cardioprotective role in global myocardial ischemia-reperfusion in female rats.     

The EEG indices of the functional status of the operator in prolonged monotonous work at a computer]

The EEG data obtained in 4-hour experiments with simulation of monotonous performance at a computer display were analyzed. A certain difference in the dynamics of the functional state was revealed between the groups of subjects which differed in their background level of cortical activation. Practically the same performance efficiency in these groups was supported by different mechanisms: via self-regulation mechanisms in the subjects with a high initial level of cortical activity and by involvement of "self-correction" realized through activation of nonspecific subcortical brain structures. The development of the excessive stress in the second group of subjects expressed in an increase of theta rhythm power density indicated the higher "physiological cost" of monotonous operator's work for persons with low level of background cortical activation.     

The influence of environmental conditions on the reproduction and distribution of epilithic lichens

Summary Humidity and solar radiation condition the distribution of lichen communities on the nuraghi of northwestern Sardinia.The growth of lichens withTrentepohlia algae is favored to the north under conditions of low light intensity and high humidity. Lichens with cyanobacteria prevail under dry conditions. Microclimatic conditions also generate selective pressures on the reproductive strategies of the species.Vegetative reproduction through soredia is maximum under extreme conditions: minimum light intensity and maximum humidity on one hand; maximum light intensity and minimum humidity on the other.For vegetative reproduction through isidia, no significant correlation was found with humidity and light: the maximum frequency of isidia was found in situations with a flow of rainwater.Gametic reproduction through spores has a very high frequency (> 80%) in intermediate microclimatic situations.     

陆军青年军人心理素质与人格、心理健康的相关研究

目的:探讨陆军青年军人心理素质与人格、心理健康的关系。方法:整群抽取陆军青年官兵881名,采用军人心理素质量表、艾森克人格问卷(EPQ)、症状自评量表(SCL-90)进行测评,进行方差分析和相关分析。结果:(1)陆军青年军人心理素质各因子分及总分与EPQ人格问卷中的E分呈显著正相关(p<0.01);与N分、P分呈显著负相关(p<0.01)。高、中、低心理素质水平军人E、P、N得分比较有显著差异(p<0.05),表现为在E量表得分上高心理素质组>中等心理素质组>低心理素质组;而在P、N量表得分上则反之。(2)陆军青年军人心理素质各因子分及总分均与SCL-90各因子分和总均分呈显著负相关(p<0.01)。高、中、低心理素质水平军人SCL-90各因子得分比较有显著差异(p<0.05),表现为低心理素质组>中等心理素质组>高心理素质组。结论:陆军青年军人心理素质与心理健康密切相关,心理素质越高,其心理健康水平也越高。     

Thermotropic behavior of lipids and the morphology of Yersinia pseudotuberculosis cells with a high content of lysophosphatidylethanolamine

The content of lysophosphatidylethanolamine (LPE) in Y. pseudotuberculosis cells was found to increase during their growth at 8 degrees C under stationary conditions (without stirring the medium) and at 37 degrees C when the medium contained glucose. The maximum level of LPE (up to 45% of the total phospholipids) was observed in cells grown at 8 degrees C under stationary conditions. Such cells showed an enhanced growth rate, a reduced yield of biomass, an altered cell morphology, and an increased cell area. The cells contained unsaturated fatty acids, phosphatidylethanolamine (PE), and total phospholipids in small amounts, whereas neutral lipids and diphosphatidylglycerol were abundant. In addition, the cells contained an amount of methylated PE and phospholipids of unknown structure. Irrespective of whether the temperature for growth was low or high, the LPE-rich cells showed a high value (32-36 degrees C) of the maximum temperature of thermal transition of lipids (Tmax). This finding is indicative of a densification of the membrane lipid matrix of the LPE-rich cells. The suggestion is made that LPE is accumulated in glucose-fermenting bacterial cells in response to stress caused by oxygen deficiency and low pH values of the growth medium. The possible relationship between LPE accumulation and the virulence of Y. pseudotuberculosis cells grown at low temperatures is discussed.     

Thermotropic behavior of lipids and the morphology of <Emphasis Type="Italic">Yersinia pseudotuberculosis</Emphasis> cells with a high content of lysophosphatidylethanolamine

The content of lysophosphatidylethanolamine (LPE) in Y. pseudotuberculosis cells was found to increase during their growth at 8 °C under stationary conditions (without stirring the medium) and at 37°C when the medium contained glucose. The maximum level of LPE (up to 45% of the total phospholipids) was observed in cells grown at 8°C under stationary conditions. Such cells showed decreas growth rate, a reduced yield of biomass, an altered cell morphology, and an increased cell area. The cells contained unsaturated fatty acids, phosphatidylethanolamine (PE), and total phospholipids in small amounts, whereas neutral lipids and diphosphatidylglycerol were abundant. In addition, the cells contained an amount of methylated PE and phospholipids of unknown structure. Irrespective of whether the temperature for growth was low or high, the LPE-rich cells showed a high value (32–36°C) of the maximum temperature of thermal transition of lipids (T _max). This finding is indicative of a densification of the membrane lipid matrix of the LPE-rich cells. The suggestion is made that LPE is accumulated in bacterial cells in response to stress caused by oxygen deficiency and pH decrease in the course of glucose fermentatin. The possible relationship between LPE accumulation and the virulence of Y. pseudotuberculosis cells grown at low temperatures is discussed.     

Neurite development in PC12 cells on flexible micro-textured substrates under cyclic stretch

We investigated the combined effect of micro-texture and mechanical strain on neuronal cell development such as neurite length and neurite density in a rat pheochromocytoma cell line (PC12 cells). Cells were seeded on flexible silicone substrates with micro-texture or no texture (smooth) and cultured under static and dynamic conditions. In the static condition substrates were not stretched and in the dynamic conditions substrates were subjected to cyclic uniaxial stretching at three different strain levels of 4%, 8%, and 16% with each at three different strain rates at 0.1, 0.5, and 1.0 Hz. Results showed that of all cell cultures there was no significant difference in neurite development between cells on smooth and textured substrates, except in the static and 4% at 0.1 Hz conditions, where micro-texture induced significantly longer neurites. With both types of substrates, a lower mechanical condition (4% at 1.0 Hz or 16% at 0.1 Hz) resulted in more and longer neurites and lower cell density, and a higher mechanical condition (16% at 1.0 Hz) resulted in fewer and shorter neurites and lower cell density as compared to the static condition. These findings suggest that the effect of the micro-texture on neurite development is more prominent in low mechanical conditions than in high mechanical conditions and that the strain level and strain rate have an interrelated effect on neurite development: a higher strain level at a lower strain rate has a similar effect as a lower strain level at a higher strain rate in terms of promoting neurite development.     

Individualities in a flock of free-roaming greylag geese: behavioral and physiological consistency over time and across situations

The concept of personality implies individual differences in behavior and physiology that show some degree of repeatability/consistency over time and across contexts. Most studies of animal personality, particularly studies of individuals' variation in physiological mechanisms, have been conducted on selected individuals in controlled conditions. We attempted to detect consistent behaviors as well as physiological patterns in greylag ganders (Anser anser) from a free-roaming flock living in semi-natural conditions. We tested 10 individuals repeatedly, in a handling trial, resembling tests for characterization of "temperaments" in captive animals. We recorded the behavior of the same 10 individuals during four situations in the socially intact flock: (1) a "low density feeding condition", (2) a "high density feeding condition", (3) a "low density post-feeding situation" and (4) while the geese rested. We collected fecal samples for determination of excreted immuno-reactive corticosterone (BM) and testosterone metabolites (TM) after handling trials, as well as the "low density feeding" and the "high density feeding" conditions. BM levels were very highly consistent over the repeats of handling trials, and the "low density feeding condition" and tended to be consistent over the first two repeats of the "high density feeding condition". Also, BM responses tended to be consistent across contexts. Despite seasonal variation, there tended to be inter-test consistency of TM, which pointed to some individual differences in TM as well. Aggressiveness turned out to be a highly repeatable trait, which was consistent across social situations, and tended to correlate with an individual's resistance during handling trials. Also, "proximity to the female partner" and "sociability" - the average number of neighboring geese in a close distance while resting - were consistent. We conclude that aggressiveness, "affiliative tendencies" and levels of excreted corticosterone and testosterone metabolites may be crucial factors of personality in geese.     

Potent inhibition of cell density-dependent apoptosis and enhancement of survival by dimethyl sulfoxide in human myeloblastic HL-60 cells

Human myeloblastic cell line HL-60 cells undergo apoptosis during in vitro culture in a cell density-dependent manner, and this cell density-dependent apoptosis was observed when the concentration of cultured cells exceeded 8–10 × 10⁵ cells/ml. Dimethyl sulfoxide (DMSO), a differentiation inducer of HL-60 cells, did not amplify, but rather potently inhibited, this apoptosis. In a low density culture condition, DMSO attenuated proliferation of HL-60 cells in spite of its inhibition of apoptosis. In contrast, DMSO did support cell survival under high cell density conditions, and DMSO-treated HL-60 cells reached an extremely high concentration of 2–3 × 10⁶ cells/ml, a condition which could never be possible in a usual culture environment. Thus, DMSO exerted dual effects on cell proliferation, i.e., growth inhibition and apoptosis inhibition, and the sum of these effects resulted in an apparently distinct phenomenon according to the culture conditions including cell density. J. Cell. Physiol. 174:135–143, 1998. © 1998 Wiley-Liss, Inc.     

Endocrine Treatment of Transsexual Persons: Extensive Personal Experience

ObjectiveThe Endocrine Society’s recently published clinical practice guidelines for the treatment of transsexual persons acknowledged the need for further information on transsexual health. We report here the experience of one provider with the endocrine treatment of transsexual persons over the past 2 decades.MethodsData on demographics, clinical response to treatment, and psychosocial status were collected on all transsexual persons receiving cross-sex hormone therapy since 1991 at the endocrinology clinic at Albany Medical Center, a tertiary care referral center serving upstate New York.ResultsThrough 2009, a total 192 male-to-female (MTF) and 50 female-to-male (FTM) transsexual persons were seen. These patients had a high prevalence of mental health and psychiatric problems (over 50%), with low rates of employment and high levels of disability. Mental health and psychiatric problems were inversely correlated with age at presentation. The prevalence of sex reassignment surgery was low (31% for MTF). The number of persons seeking treatment has increased substantially in recent years. Cross-sex hormone therapy achieves very good results in FTM persons and is most successful in MTF persons when initiated at younger ages.ConclusionTranssexual persons seeking hormonal therapy are being seen with increasing frequency. The dysphoria present in many transsexual persons is associated with significant mood disorders that interfere with successful careers. Starting therapy at an earlier age may lessen the negative impact on mental health and lead to improved social outcomes. However, significant barriers exist, such as insufficient insurance coverage, which limit comprehensive care. (Endocr Pract. 2013;19:644-650)     

Evaluation of the Validity of Job Exposure Matrix for Psychosocial Factors at Work

Objective

To study the performance of a developed job exposure matrix (JEM) for the assessment of psychosocial factors at work in terms of accuracy, possible misclassification bias and predictive ability to detect known associations with depression and low back pain (LBP).

Materials and Methods

We utilized two large population surveys (the Health 2000 Study and the Finnish Work and Health Surveys), one to construct the JEM and another to test matrix performance. In the first study, information on job demands, job control, monotonous work and social support at work was collected via face-to-face interviews. Job strain was operationalized based on job demands and job control using quadrant approach. In the second study, the sensitivity and specificity were estimated applying a Bayesian approach. The magnitude of misclassification error was examined by calculating the biased odds ratios as a function of the sensitivity and specificity of the JEM and fixed true prevalence and odds ratios. Finally, we adjusted for misclassification error the observed associations between JEM measures and selected health outcomes.

Results

The matrix showed a good accuracy for job control and job strain, while its performance for other exposures was relatively low. Without correction for exposure misclassification, the JEM was able to detect the association between job strain and depression in men and between monotonous work and LBP in both genders.

Conclusions

Our results suggest that JEM more accurately identifies occupations with low control and high strain than those with high demands or low social support. Overall, the present JEM is a useful source of job-level psychosocial exposures in epidemiological studies lacking individual-level exposure information. Furthermore, we showed the applicability of a Bayesian approach in the evaluation of the performance of the JEM in a situation where, in practice, no gold standard of exposure assessment exists.     

贯叶连翘提取物对小鼠免疫性心肌炎心肌纤维化的影响及其机制*

目的:研究贯叶连翘提取物(HPE)对小鼠实验性免疫性心肌炎心肌纤维化(MFEAM)的影响。方法:利用猪心肌肌球蛋白免疫易感鼠系,建立小鼠MFEAM模型,将MFEAM模型组小鼠随机分为: MFEAM模型组(n=14)、HPE100 mg/kg组(n=13)、HPE 40 mg/kg组(n=13)、Cap 50 mg/kg对照组(n=13)。各组药物每次均分别以0.4 ml生理盐水溶解,采用灌胃给药方式,每天2次,共60 d;正常对照组(n=10),MFEAM模型组按上述方法同体积同疗程给予生理盐水。通过观察小鼠一般情况,测定心脏重量、脾脏重量与体重之比,检测小鼠血清中I型前胶原N端前肽(PINP)、III型前胶原N端前肽(PIIINP)含量及转化生长因子-β1(TGF-β1)浓度,Masson染色显微镜观察心肌纤维化(MF)程度及胶原容积分数(CVF)测定,Western blot检测心肌TGF-β1蛋白表达。结果:MFEAM模型组小鼠血清中TGF-β1浓度及PINP、PIIINP含量显著升高,MF程度及CVF增加,心肌TGF-β1蛋白表达上调,与正常组比较差异有显著性意义(P＜0.05或P＜0.01);而HPE 40 mg/kg、100 mg/kg及Cap对照组血清PINP、PIIINP含量及TGF-β1浓度均减少,不同HPE或Cap剂量显著改善或降低MFEAM模型小鼠MF程度及CVF,不同程度下调心肌TGF-β1蛋白表达水平,与MFEAM模型组比较差异有显著性意义(P＜0.05或P＜0.01)。结论:HPE对MF有治疗作用,可能与其减少胶原蛋白沉积,抑制TGF-β1信号通路有关。     

Origin and fate of the lysophosphatidylethanolamine in a chain-forming mutant (envC) of Escherichia coli

The role of phospholipid metabolism in the functioning of the bacterial envelope was investigated in the chain-forming Escherichia coli envC. Lysophosphatidylethanolamine (LPE) which accumulated in this strain during growth was identified as the product of phosphatidylethanolamine (PE) hydrolysis by a phospholipase A1, i.e. 2-acylLPE. Isotopically labelled LPE transferred into intact mutant and parent cells by liposome/bacteria interaction was rapidly reacylated to PE. However, in envC the final PE/LPE ratio was lower than that in the parent, thus showing that the fate of LPE is modified. Crude cell extracts degraded LPE to a lesser extent in envC than in the parent but were unable to promote reacylation activity under our experimental conditions. In both strains, the lysophospholipase activity was neither calcium-dependent nor inhibited by the SH-group inhibitors pHMB or pCMPS, and hydrolysed 1-acylLPE as well as 2-acylLPE. These results indicate the existence of a deacylation-reacylation cycle in E. coli and show that this cycle is perturbed in envC cells, especially at the lysophospholipase step.     

Intermittent exposure to toxic compounds in the working-zone atmosphere viewed from the aspect of hygienic standardization

Four highly cumulative substances (carbon tetrachloride, 1,1,2,2-tetrachloroethane, benzene and dimethylformamide) were studied at two exposure levels under a monotonous and an intermittent exposure regimen in subacute experiments on rats. The biological effect produced by the intermittent concentrations as compared with the stable concentrations under time-weighted average concentrations depended both on the physiochemical properties and biological action of the poisons as well as on the exposure level. The intermittent concentration rises within certain limits (threefold as a rule) were injurious with some of the substances at a relatively high exposure level, but were not detrimental as compared with stable concentrations at a low exposure level. The other substances showed no difference between the effect of the monotonous and the intermittent regimens at either low or high exposure levels. The results of these studies form an experimental basis for a dual hygienic standardization: the establishment of maximum and average-shift admissible concentrations for the compounds studied as well as other highly cumulative substances.     

Taste Sensitivity and Aging: High Incidence of Decline Revealed by Repeated Threshold Measures

Contrary to what has often been said about the subject, declinein taste sensitivity with aging characterizes virtually everybodyand is not the artificial result of averaging large losses ofa minority with negligible losses of a majority. This assertionis supported by six repeated measures of sucrose thresholdsin each of 15 older (over 64 years) and 15 younger (under 27years) adult subjects. Threshold was determined by a proceduresimilar to past studies and with the same results: much scatterand considerable overlap between the thresholds of younger andolder subjects. A quite contrasting picture emerges, however,when each subject's six threshold determinations are averaged.Averaging shrinks the individual differences among subjects,as well as the over-lap between younger and older subjects.Although virtually all elderly subjects now revealed taste weakness,reliable individual differences in degree of weakness aboundamong them, suggesting various individual rates of physiologicalaging. In contrast young persons exhibit greater uniformityof sensitivity. These findings were brought out by inter-testcorrelations, which were much higher for the older subjects;i.e. an older subject who tended to score high (low) on onetest tended to score high (low) on the other tests. The studyconfirms the tenuous nature of brief threshold tests as indicesof personal sensitivity as found earlier also in olfactory thresholdsand in concurrent measurement of two-point touch thresholdsin the present study. This revealed correlated losses betweenrepeated taste and touch thresholds from the same 15 older subjects,unrelated to their exact chronological age. Chem. Senses 20:451–459, 1995.     

Protective effect of brown Brazilian propolis against acute vaginal lesions caused by herpes simplex virus type 2 in mice: involvement of antioxidant and anti‐inflammatory mechanisms

Propolis has been highlighted for its antioxidant, anti‐inflammatory and antiviral properties. The purpose of this study was to investigate if brown Brazilian hydroalcoholic propolis extract (HPE) protects against vaginal lesions caused by herpes simplex virus type 2 (HSV‐2) in female BALB/c mice. The treatment was divided in 5 days of pre‐treatment with HPE [50 mg·kg^–1, once a day, intragastric (i.g.)], HSV‐2 infection [10 µl of a solution 1 × 10² plaque‐forming unit (PFU·ml^–1 HSV‐2), intravaginal inoculation at day 6] and post‐treatment with HPE (50 mg·kg^–1) for 5 days more. At day 11, the animals were killed, and the in vivo analysis (score of lesions) and ex vivo analysis [haematological and histological evaluation; superoxide dismutase (SOD), catalase (CAT) and myeloperoxidase (MPO) activities; reactive species (RS), tyrosine nitration levels, non‐protein thiols (NPSH) and ascorbic acid (AA) levels] were carried out. HPE treatment reduced extravaginal lesions and the histological damage caused by HSV‐2 infection in vaginal tissues of animals. HPE was able to decrease RS, tyrosine nitration, AA levels and MPO activity. Also, it protected against the inhibition of CAT activity in vaginal tissues of mice. HPE promoted protective effect on HSV‐2 infected animals by acting on inflammatory and oxidative processes, and this effect probably is caused by its antioxidant and anti‐inflammatory properties. Copyright © 2011 John Wiley & Sons, Ltd.     

Local-pooled-error test for identifying differentially expressed genes with a small number of replicated microarrays

MOTIVATION: In microarray studies gene discovery based on fold-change values is often misleading because error variability for each gene is heterogeneous under different biological conditions and intensity ranges. Several statistical testing methods for differential gene expression have been suggested, but some of these approaches are underpowered and result in high false positive rates because within-gene variance estimates are based on a small number of replicated arrays. RESULTS: We propose to use local-pooled-error (LPE) estimates and robust statistical tests for evaluating significance of each gene's differential expression. Our LPE estimation is based on pooling errors within genes and between replicate arrays for genes in which expression values are similar. We have applied our LPE method to compare gene expression in na?ve and activated CD8+ T-cells. Our results show that the LPE method effectively identifies significant differential-expression patterns with a small number of replicated arrays. AVAILABILITY: The methodology is implemented with S-PLUS and R functions available at http://hesweb1.med.virginia.edu/bioinformatics     

Degradation of Benzene,Toluene and Xylene by Pseudomonas aeruginosa Engineered with the Vitreoscilla Hemoglobin Gene

This study concerns the potential use of Pseudomonas aeruginosa expressing the Vitreoscilla hemoglobin gene for the degradation of important harmful aromatic compounds such as benzene, toluene, and xylene (BTX). The use of these compounds by both strains was determined as the production of cell mass (viable cell number) in a minimal medium containing any one of the BTX compounds as the sole carbon and energy source. Furthermore, the BTX degradation capability of both strains was monitored by measuring the production of 3‐methylcatechol, a common intermediate. For the cells of the logarithmic phase, which were grown at high aeration/high agitation or low aeration/low agitation, the engineered strain showed a better growth rate than the host strain. With the benzene in the medium, the recombinant strain exhibited a higher (up to 4‐fold) cell density than the parental wild‐type strain at this phase. In contrast, regarding the cells of the late stationary phase under high aeration/high agitation conditions, the host strain had generally higher viable cell numbers than the recombinant strain. At this phase this difference was, however, less significant under the conditions of low aeration/low agitation. Similarly, in toluene containing medium (at high aeration/high agitation) the recombinant strain showed a higher cell density which was from a 15‐fold to almost one order of magnitude greater than its parental strain during the logarithmic phase where the cell density of P. aeruginosa remained nearly constant. Contrary to the results with benzene and toluene, both strains exhibited similar growth characteristics when they were grown in the presence of xylene. The positive effect of the oxygen uptake by the recombinant system on the BTX metabolizing activity was also apparent in a high accumulation of 3‐methylcatechol in the cultures of the recombinant strain. At certain points of incubation, the hemoglobin expressing strain showed a significantly (p < 0.05) higher 3‐methylcatechol accumulation than the host strain. These results demonstrated the possible potential of the Vitreoscilla hemoglobin as an efficient oxygen uptake system for the bioremediation of some compounds of environmental concern.     

Some properties of an endodextranase inhibitor from continuous cultures of Streptococcus sobrinus.

Cell-free filtrates of Streptococcus sobrinus, cultured at low growth rate in the chemostat, contain a dextranase inhibitor that can completely inhibit the activity of S. sobrinus endodextranase. The range of conditions under which inhibition occurs, and the situations in which enzyme activity can reappear, have been examined in continuous cultures of strain 6715-13WT and the dextranase-deficient mutant 6715-13-201. A purified preparation of the inhibitor was specific for S. sobrinus dextranase, having no action on dextranases from other oral streptococci. The percentage inhibition of S. sobrinus dextranase varied with the enzyme concentration, and the complete inhibition of low amounts of enzyme indicated a very tight bond between the inhibitor and the enzyme.     

Mycobacterium fortuitum and Mycobacterium chelonae biofilm formation under high and low nutrient conditions

The rapidly growing mycobacteria (RGM) are broadly disbursed in the environment. They have been recovered from freshwater, seawater, wastewater and even potable water samples and are increasingly associated with non-tuberculous mycobacterial disease. There is scant evidence that non-tuberculous mycobacteria (NTM) and RGM form biofilms. Therefore, an experimental system was designed to assess the ability of RGM to form biofilms under controlled laboratory conditions. A flat plate reactor flow cell was attached to either a high or low nutrient reservoir and monitored by image analysis over time. Two surfaces were chosen for assessment of biofilm growth: silastic which is commonly used in medical settings and high density polyethylene (HDPE) which is prevalent in water distribution systems. The results show that Mycobacterium fortuitum and M. chelonae formed biofilms under both high and low nutrient conditions on both surfaces studied. These results suggest that RGM may form biofilms under a variety of conditions in industrial and medical environments.