Characterization of the Rhodococcus sp. BPG-8 resorcinol hydroxylase

A thermo-unstable hydroxylase was isolated from a Rhodococcus sp. BPG-8. Activity for the partially purified hydroxylase was enhanced and stabilized in the presence of FAD and catalase. The V_max values for the oxidation of NADH was 0.28 μmoles · min^?1 · mg^?1 protein and K_m value was 8.3 μM in the presence of these compounds, while in their absence the V_max value was reduced to 0.09 μmoles · min^?1 · mg^?1 protein while the K_m value changed to 16.1 μM . Resorcinol hydroxylase activity was optimal at pH 7.0, and 25° C. The optimal substrate concentrations were 68 μM and 125 μM in the presence and absence of FAD/catalase, respectively. Chloride ion, and metal ions inhibited the resorcinol hydroxylase activity. The resorcinol hydroxylase utilized various other substrates, and did not influence the hydroxylase activity in the presence of resorcinol.     

Radiorespirometric analysis of glucose dissimilation in Rhodococcus sp. An 117 and An 213

Radiorespirometric experiments were carried out by incubating various types of resting cells of either Rhodococcus sp. An 117 or Rhodococcus sp. An 213 under aerobic conditions with differentially labelled glucose. The results obtained indicate the constitutive nature of glucose catabolism in both these strains, i.e. there was no principle shift in glucose dissimilation during cell growth with different carbon substrates. On the basis of the observed ratios of percentage (cumulative) ¹⁴CO₂-formation from (6-¹⁴C)glucose and (1-¹⁴)glucose, the glycolytic EMP-pathway was calculated to be the predominant catabolic route being operative to an extent of about 95% (strain An 117) and 78% (strain An 213).     

Purification,characterization, and biological cytotoxic activity of the extracellular cholesterol oxidase produced by Castellaniella sp. COX

A new bacterial strain producing extracellular cholesterol oxidase (ChOx) was isolated and identified as Castellaniella sp. COX. The ChOx was purified by salting-out and ion-exchange chromatography up to 10.4-fold, with a specific activity of 15 U/mg with a molecular mass of 59 kDa. The purified ChOx exhibited pH 8.0 and temperature 40°C for its optimum activity. The enzyme showed stability over a wide pH range and was most stable at pH value 7.0, and at pH 8.0, it retained almost 86% of its initial activity after 3 h of incubation at 37°C. The enzyme possessed a half-life of 8 h at 37°C, 7 h at 40°C, and 3 h at 50°C. A Lineweaver–Burk plot was calibrated to determine its K_m (0.16 mM) and V_max (18.7 μmol·mg⁻¹·min⁻¹). The ChOx activity was enhanced with Ca²⁺, Mg²⁺, and Mn²⁺ while it was inhibited by Hg²⁺, Ba²⁺, Fe²⁺, Cu²⁺, and Zn²⁺ ions. Organic solvents like acetone, n-butanol, toluene, dimethyl sulfoxide, chloroform, benzene, and methanol were well tolerated by the enzyme while iso-propanol and ethanol were found to enhance the activity of purified ChOx. ChOx induced cytotoxicity with an IC₅₀ value of 1.78 and 1.88 U/ml against human RD and U87MG established cell lines, respectively, while broadly sparing the normal human cells.     

Fortuitous resorcinol metabolism by a phloroglucinol-induced Rhodococcus sp. BPG-8

A Rhodococcus sp. BPG-8 isolated from oil-rich soil in Newfoundland was capable of using phloroglucinol as a sole source of carbon and energy. Culture filtrates of cells grown on resorcinol were extracted and analyzed using gas chromatography-mass spectra (GC-MS), thin layer chromatography (TLC), and ultraviolet spectrophotometry. Phloroglucinol induced cell-free extracts revealed the presence of phloroglucinol hydroxylase that hydroxylated resorcinol. Meta-cleavage of 1,2,4-benzenentriol occurs at a slow rate. A tentative biotransformation pathway for resorcinol by Rhodococcus sp. BPG-8 is discussed.     

Radiation-induced radical formation and crosslinking in aqueous solutions of N-isopropylacrylamide

To investigate chain-initiating and crosslinking mechanisms, radical formation in dilute aqueous solutions of N-isopropylacrylamide (NIPAAm) and poly-NIPAAM was studied using electron pulse radiolysis with optical detection at room temperature. Several transients of NIPAAm generated by reactions with electrons, hydroxyl radicals and hydrogen atoms were observed. Electron attachment to the carboxyl group (k_e = 9.0 x 10⁹ dm³ · mol⁻¹ · s⁻¹) forms the radical anion, which undergoes fast and reversible protonation (pK_a = 7.8) at the carboxyl oxygen. At pH > pK_a, slow and irreversible protonation of the electron adduct at the vinyl group leads to the α-carboxyalkyl radical CH₃(^.CH)CONHCH(CH₃)₂, which is also formed by addition of H atoms to NIPAAm (k_H = 7.3 × 10⁹ dm³ · mol⁻¹ · s⁻¹). Addition of OH radicals (k_OH = 5.4 × 10⁹ dm³ · mol⁻¹ · s⁻¹) forms CH₂(OH)(^.CH)CONHCH(CH₃)₂. Hydrogen abstraction was not observed in the case of NIPAAm monomer, but it was found for the reaction of OH radicals with thermally polymerized NIPAAm. Semi-empirical quantum chemical calculations support the assignment of the observed spectra to the radicals. A reaction mechanism for the formation of crosslinks is discussed.     

Etherolytic cleavage of 4-(2,4-dichlorophenoxy)butyric acid and 4-(4-chloro-2-methylphenoxy)butyric acid by species of Rhodococcus and Aureobacterium isolated from an alkaline environment

Bacterial strains were isolated from the concrete rubble of a demolished herbicide production plant. The predominant feature of these strains was the etherolytic cleavage of 4-(2,4-dichlorophenoxy)butyric acid (DCPB) and 4-(4-chloro-2-methylphenoxy)butyric acid (MCPB) while liberating 2,4-dichlorophenol (DCP) and 4-chloro-2-methylphenol (MCP) respectively. Some of the isolates were identified by 16S rDNA sequence analysis and shown to belong to the genera Aureobacterium sp. (strain K2-17) and Rhodococcus (Rh. erythropolis K2-12). The other strains isolated clustered into these two groups according to fatty acid analysis. Etherolytic cleavage proceeded under neutral to alkaline conditions with an optimum at around pH 8.5. With Aureobacterium sp. No. K2-17, the degradation rate was zero at a pH of 6 but as much as 60% of the maximum activity was observed at pH 10.5. With Rh. erythropolis K2-12, by contrast, pronounced activity was detected at pH 6.5 while degradation was no longer observed at pH 10.5. The maximum rates of cleavage were about 1 mmol DCPB/h · g dry mass with Aureobacterium sp. No K2-17 and about 0.6 mmol DCPB/h · g dry mass with Rh. erythropolis K2-12. DCPB and MCPB were utilized to the same extent. Substrate cleavage and product formation (DCP) proceeded at almost equal rates with Aureobacterium sp. No. K2-17 and Rh. erythropolis K2-12, which indicates that this compound was not further metabolized. Only phenoxybutyric acid compounds served as substrates; phenoxyacetic acid and phenoxypropionic acid derivatives were not utilized by these strains.     

The N-terminal amino acid sequences of Brevibacterium sp. R312 nitrile hydratase

Nitrile hydratase from Brevibacterium sp. R312 was purified to homogeneity. The isoelectric point was 5.75. The two kinds of subunits were separated by reverse phase HPLC and their N-terminal amino acid sequences were found to be identical to those of Rhodococcus sp. N-774 nitrile hydratase.     

Decrease in the proportion of CD24hiCD38hi B cells and impairment of their regulatory capacity in type 1 diabetes patients

B10 cells restore immune balance by producing interleukin (IL)-10. Impaired B10 cell responses are related to numerous autoimmune diseases. However, the function of B10 cells in type 1 diabetes (T1D) patients is controversial. We hypothesized that there are numerical and functional defects of B10 cells in T1D. Sixty-two patients with T1D and 74 healthy volunteers were included in our study. We showed that B10 cells in human peripheral blood belong to a CD24^hiCD38^hi B cell subpopulation. CD24^hiCD38^hi B cells from healthy individuals possessed regulatory capacity, suppressed interferon (IFN)-γ, tumor necrosis factor (TNF)-α and IL-17A production and promoted IL-4 production and forkhead box protein 3 (FoxP3) expression in CD4⁺ T cells through an IL-10-dependent mechanism. Compared to healthy controls, B10 cell percentages in T1D were significantly lower (5·6 ± 3·5 versus 6·9 ± 3·3%; P < 0·05), produced less IL-10 (15·4 ± 4·3 versus 29·0 ± 4·5%; P < 0·001) and lacked regulatory capacity. In addition, Pearson’s correlation analysis showed that the frequency of circulating B10 cells was negatively correlated with the frequency of CD4⁺IFN-γ⁺ and CD4⁺TNF-α⁺ T cells (r = −0·248 and r = −0·283, P = 0·008 and P = 0·017, respectively), positively correlating with the frequency of CD4⁺CD25⁺FoxP3⁺ T cells (r = 0·247, P = 0·001). These data offer direct proof that there is a deficiency of circulating CD24^hiCD38^hi B cells in peripheral blood of patients with T1D, which participate in the T1D immune imbalance involved in the development of T1D.     

Chirality induction in cyclopolymerization, 5. Template effect of chiral acyclic 1,2-glycols on the cyclo-copolymerizations of (S)-1,2-propanediyl and (2S,3S)-2,3-butanediyl bis(4-vinylbenzoate)s with styrene

The copolymerizations of (S)-1,2-propanediyl and (2S,3S)-2,3-butanediyl bis(4-vinyl-benzoate)s ( 2a and 2b ) (M₁) with styrene (M₂) were carried out using 2,2′-azoisobutyronitrile in toluene at 60 °C. For the cyclocopolymer 3 , the extent of cyclization of 3b is higher than that of 3a . The monomer reactivity ratios are r₁ = 8.34 and r₂ = 0.27 for 2a and r₁ = 6.82 and r₂ = 0.19 for 2b . The specific rotation ([α] in deg · dm⁻¹ · g⁻¹ · cm³ c = 1.0 g · dL⁻¹; CHCl₃) changes from +230 to +176 for 3a and from +319 to +150 for 3b . After removing the chiral templates, the resulting poly[(methyl 4-vinylbenzoate)-co-styrene]s showed a specific rotation ([α] in deg · dm⁻¹ · g⁻¹ · cm³ c = 1.0 g · dL⁻¹; CHCl₃) of −2 for 4a and of −8 for 4b , indicating that the (2S,3S)-2,3-butanediyl template shows a higher ability to cause asymmetric induction by comparison with the (S)-1,2-propanediyl one. A split Cotton effect due to the positive chirality was observed in the CD spectrum of 2 and the reversed one for 4 . According to the CD exciton chirality method, the clockwise-twist of two 4-vinylbenzoate for 2 transmitted its chirality to 4 in which two 4-vinylbenzoyl groups are twisted counterclockwise, i. e., an (R,R)-configuration of vicinal (methyl 4-vinylbenzoate) units in the main chain.     

Characterization of gelatinase produced by Antarctic Mrakia sp.

In the present study, 20 psychrotolerant yeast species isolated from the soils of King George Island in the sub‐Antarctic region were evaluated for the production of extracellular gelatinase, an enzyme with high potential for applications in diverse areas, such as food and medicine. The production of extracellular gelatinase was confirmed in the yeasts Metschnikowia sp., Leucosporidium fragarium, and Mrakia sp., the last one being the yeast in which the highest gelatinase activity was detected. The enzyme was purified from cultures of Mrakia sp., and the effect of different physical–chemical factors on its activity was determined. The gelatinase produced by Mrakia sp. would correspond to a protein of relative molecular weight (rMW) 37,000, which displayed the highest activity at 36°C, pH 7.0, 10 mM CaCl ₂, and 5 mM ZnSO ₄.     

Effect of zinc chloride on the radical polymerization of cyclohexyl acrylate

The paper presents a study of the radical polymerization of cyclohexyl acrylate (CHA) in the presence of ZnCl₂. It was found by IR, ¹H NMR, and ¹³C NMR spectroscopy that a complex of ZnCl₂ with CHA is formed. For copolymerization of CHA with vinylidene chloride, both the Q- and e-value of CHA increased with the ZnCl₂ concentration. The initiation rate and k/k_t were determined using DPPH as an inhibitor. It was found that ZnCl₂ did not affect the initiation rate. The k_p value of CHA was determined to be about 2720 1 · mol⁻¹ · s⁻¹ in the absence and 4710 1 · mol⁻¹ · s⁻¹ in the presence of ZnCl₂ by the rotating sector method. The enhanced polymerization rate of CHA in the presence of ZnCl₂ can be ascribed to the large k_p value. The termination rate constant is not significantly affected by the presence of ZnCl₂.     

Phenotypic characterization of regulatory T cells from antiretroviral‐naive HIV‐1‐infected people

Regulatory T (Treg) cells play a key role in dampening excessive immune activation. However, antiretroviral therapy (ART) ‐naive HIV‐1 infection maintains the immune system in a sustained state of activation that could alter both Treg cell surface markers and functions. As Treg cell surface markers are directly linked to their functions the overall objective of this study was to determine how ART‐naive HIV infection affects the phenotypic properties of Treg cells. Our data showed that in ART‐naive HIV‐1 infection, Treg cells are dominated by effector (CD45RA⁺ CD27⁻ CCR7⁻ CD62L⁻) and effector memory (CD45RA⁻ CD27⁻ CCR7⁻ CD62L⁻) cells. In contrast Treg cells from HIV‐negative individuals were mainly naive (CD45RA⁺ CD27⁺ CCR7⁺ CD62L⁺) and central memory (CD45RA⁻ CD27⁺ CCR7⁺ CD62L⁺) cells. Whereas effector and effector memory Treg cells showed enhanced expression of CD39 (P < 0·05), CD73 (P < 0·001), HLA‐DR and CD38 (P < 0·001); naive and central memory Treg cells showed a significant reduction in the expression of these markers. Overall Treg cell frequencies within total CD4⁺ T cells correlated positively with plasmatic HIV‐1 viral load. As increased viral load is associated with augmented CD4⁺ T‐cell destruction; this could suggest a resistance of peripheral Treg cells to HIV‐1 destruction. Hence the modulation of Treg cell phenotype and frequencies could be considered in designing immunotherapeutic strategies targeting immune system restoration during HIV‐1 infection.     

Degradation of aniline and monochloroanilines by Rhodococcus sp. An 117 and a pseudomonad: A comparative study

Two newly isolated aniline-degrading bacterial strains were characterized with regard to their enzyme systems responsible for aniline catabolism. One of them identified as a Rhodococcus sp. metabolized aniline exclusively via the β-ketoadipate pathway by means of inducible enzymes. The aniline-degrading enzyme system of the second isolate, presumably a pseudomonad, was shown to consist of an inducible aniline-converting enzyme and constitutive meta-pathway enzymes. Both isolates failed to metabolize monochlorinated anilines in the absence of additional carbon sources. To explain this the ring-cleaving enzymes of both isolates were examined for their substrate specificities. Furthermore, the effect of 4-chlorocatechol on the enzymes catalyzing aniline conversion and catechol oxygenation was investigated.     

Variation of bcl-2 expression in breast ducts and lobules in relation to plasma progesterone levels: overexpression and absence of variation in fibroadenomas

Some women with benign breast disease eventually develop breast cancer. The mammary gland undergoes tissue remodelling according to hormonal influences, involving a balance between quiescence, proliferation, and mechanisms of cell death. Proliferation and/or apoptotic events could therefore be investigated to help understand the mechanisms of benign lesion formation and identify mastopathies with a poor prognosis. bcl-2 expression was analysed by immunohistochemistry in 75 benign mastopathies. Protein levels were quantitated with an image analyser in various epithelial structures on frozen sections, including adenoses, fibroadenomas, ductal epithelial hyperplasias, cysts, and apparently normal surrounding lobules and ducts. bcl-2 levels were equivalent in apparently normal lobules and ducts, as well as in cysts and ductal hyperplasias. bcl-2 staining was significantly higher in fibroadenomas, known to be of lobular origin [mean=10·1, quantitative immunochemistry score (QIC) arbitrary units (AU), n=19], than in normal lobules (mean=5·1 AU, n=43, P=7×10⁻⁵). bcl-2 levels in normal lobules and ducts varied according to the menstrual cycle, being higher during the follicular than the luteal phase (P=1·8×10⁻² and P=1·7×10⁻² respectively). This was further supported by a statistical link (P=5×10⁻³) between high levels of circulating progesterone and weak bcl-2 staining in lobules and ducts. This progesterone-dependent variation was absent in fibroadenomas. No statistical correlation was found between bcl-2 expression and circulating levels of oestradiol, and follicle-stimulating or luteotrophic hormones. Although these are only preliminary results, they suggest an influence of progesterone on bcl-2 expression which might be lost in fibroadenomas. A hypothesis is proposed concerning the potential involvement of altered regulation of the apoptotic process in the formation of such benign lesions. © 1997 John Wiley & Sons, Ltd.     

Nitroxide‐Mediated Polymerization of Methyl Methacrylate Using an SG1‐Based Alkoxyamine: How the Penultimate Effect Could Lead to Uncontrolled and Unliving Polymerization

Summary: The nitroxide‐mediated polymerization (NMP) of MMA initiated with a new crowded SG1‐based alkoxyamine was performed. Contrary to the results expected after a kinetic analysis (Fischer's diagram), the polymerization of MMA at 45 °C with SG1 showed only partial control and livingness during the first 15% of conversion. Simulations using PREDICI highlighted that the kinetic rate constants currently in use had not been correctly estimated and that a strong penultimate effect drastically increased the equilibrium constant K (7 × 10⁻⁷), preventing a well‐controlled polymerization. Experimental determination of the k_c value (1.4 × 10⁴ L · mol⁻¹ · s⁻¹) confirmed a strong penultimate effect on the recombination reaction, whereas for the dissociation reaction this effect is lower (k_d = 10⁻² · s⁻¹).

Nitroxide‐mediated polymerization of MMA at 45 °C initiated with a new crowded SG1‐based alkoxyamine.     

Testing of acetaminophen in support of the international multilaboratory in vivo rat Pig-a assay validation trial

Acetaminophen, a nonmutagenic compound as previously concluded from bacteria, in vitro mammalian cell, and in vivo transgenic rat assays, presented a good profile as a nonmutagenic reference compound for use in the international multilaboratory Pig-a assay validation. Acetaminophen was administered at 250, 500, 1,000, and 2,000 mg·kg⁻¹·day⁻¹ to male Sprague Dawley rats once daily in 3 studies (3 days, 2 weeks, and 1 month with a 1-month recovery group). The 3-Day and 1-Month Studies included assessments of the micronucleus endpoint in peripheral blood erythrocytes and the comet endpoint in liver cells and peripheral blood cells in addition to the Pig-a assay; appropriate positive controls were included for each assay. Within these studies, potential toxicity of acetaminophen was evaluated and confirmed by inclusion of liver damage biomarkers and histopathology. Blood was sampled pre-treatment and at multiple time points up to Day 57. Pig-a mutant frequencies were determined in total red blood cells (RBCs) and reticulocytes (RETs) as CD59-negative RBC and CD59-negative RET frequencies, respectively. No increases in DNA damage as indicated through Pig-a, micronucleus, or comet endpoints were seen in treated rats. All positive controls responded as appropriate. Data from this series of studies demonstrate that acetaminophen is not mutagenic in the rat Pig-a model. These data are consistent with multiple studies in other nonclinical models, which have shown that acetaminophen is not mutagenic. At 1,000 mg·kg⁻¹·day⁻¹, Cmax values of acetaminophen on Day 28 were 153,600 ng/ml and 131,500 ng/ml after single and repeat dosing, respectively, which were multiples over that of clinical therapeutic exposures (2.6–6.1 fold for single doses of 4,000 mg and 1,000 mg, respectively, and 11.5 fold for multiple dose of 4,000 mg) (FDA 2002). Data generated were of high quality and valid for contribution to the international multilaboratory validation of the in vivo Rat Pig-a Mutation Assay.     

Synthesis and optical properties of polyurethanes containing a highly NLO active chromophore

Two types of new polyurethanes with a highly NLO active chromophore, 2-[4-[4-[bis(2-hydroxyethyl)amino]phenylazo]benzylidene]malonitrile (HAPM), in the polymer side chain were synthesized (PU1-DCN and PU2-DCN) and characterized. The diisocyanate components of the polymers are 2,4-tolylene diisocyanate and 3,3′-dimethoxybiphenyl-4,4′-ylene diisocyanate. The molecular weights of PU1-DCN and PU2-DCN were determined to be M̄_w = 23000 (M̄_w/M̄_n = 2.19) and M̄_w = 22000 (M̄_w/M̄_n = 2.34), respectively. The final products are readily soluble in polar aprotic organic solvents, like tetrahydrofuran, N,N-dimethylformamide, cyclohexanone, etc. Good optical quality films were obtained by spin coating. The glass transition temperatures of both polymers were found to be 158–159°C. They showed no melting points in the DSC curves, suggesting an amorphous phase. It was found that the electro-optic coefficient of PU1-DCN was r₃₃ = 62.7 pm · V⁻¹ at 633 nm wavelength. The macroscopic second-order hyperpolarizability at 1064 nm wavelength was determined to be χ⁽²⁾ = 136 pm · V⁻¹ for PU1-DCN and χ⁽²⁾ = 120 pm · V⁻¹ for PU2-DCN.     

New shuttle vectors for Rhodococcus sp. R312 (formerly Brevibacterium sp. R312), a nitrile hydratase producing strain

Two shuttle vectors named pRC52 (10.7 Kb) and pRK52 (12.2 Kb) carrying chloramphenicol (Cm) and chloramphenicol plus kanamycin (Km) resistance genes, respectively, were constructed by fusion of a cryptic plasmid pBL13869 (replicon pBL1, 5.8 Kb) from Brevibacterium lactofermentum ATCC13869 with pBR328 E. coli plasmid. Transformation of Rhodococcus sp. R312 (formerly Brevibacterium sp. R312) protoplasts was realised with an efficiency of 28 transformants per μg of DNA.     

Breakthrough of ultraviolet light from various brands of fluorescent lamps: Lethal effects on DNA repair-defective bacteria

In a comparative study of 17 pairs of 15 W fluorescent lamps intended for use in homes and purchased in local stores, we detect over 10-fold differences in UVB + UVC emissions between various lamps. This breakthrough of ultraviolet (UV) light is in part correlated with ability of lamps to kill DNA repair-defective recA⁻uvrB⁻ Salmonella. Relative proficiency of lamps in eliciting photoreactivation of UV-induced DNA lesions also plays a prominent role in the relative rates of bacterial inactivation by emissions from different lamps. Lamps made in Chile, such as Philips brand lamps and one type of General Electric lamp, produce for less UVB + UVC and fail to kill recA⁻uvrB⁻ bacteria. In contrast, all tested lamps manufactured in the USA, Hungary, and Japan exhibit readily observed deleterious biological effects. When an E. coli recA⁻uvrB⁻phr⁻ (photolyase-negative) triple mutant is used for assay, lethal radiations are detected from all lamps, and single-hit exponential inactivation rates rather closely correlate to amount of directly measured UVB + UVC output of each pair of lamps. Although all lamps tested may meet international and United States standards for radiation safety, optimal practices in lamp manufacture are clearly capable of decreasing human exposure to indoor UV light. © 1996 Wiley-Liss, Inc.     

Distribution of subcutaneous fat and muscle thicknesses in young and middle-aged women

Thicknesses of subcutaneous fat tissue at 13 sites (triceps, biceps, forearm, subscapular, abdomen, suprailiac, axilla, chest, quadriceps, suprapatellar, hamstrings, posterior calf, medial calf), and muscle tissue at nine sites (triceps, biceps, forearm, subscapular, abdomen, quadriceps, suprapatellar, hamstrings, posterior calf) were determined by using the B-mode ultrasound technique. Subjects were 36 young (18–29 years) and 44 middle-aged women (45–64 years). Body density averaged 1.047 ± 0.007 g · ml⁻¹ (SD) for the young, and 1.022 ± 0.005 g · ml⁻¹ for the middle-aged women. The middle-aged women showed significantly thicker subcutaneous fat than the young at all sites, and the relative differences between the two groups were larger on the trunk and adjacent sites. Muscle thicknesses on the trunk and quadriceps were significantly higher in the young women than in the middle-aged, but values for the upper extremities and calf were not significant between the two groups. The sum of subcutaneous fat thicknesses at 13 sites was significantly correlated with fat mass relative to the second power of stature (FM · St⁻²) in both groups, r = 0.766 (P < 0.05) for the young and r = 0.803 (P < 0.05) for the middle aged women. For subcutaneous fat thickness per unit FM · St⁻², the young women showed significantly higher values than the middle-aged on both the upper and lower extremities. The sum of muscle thicknesses at nine sites was significantly correlated with fat-free mass per unit stature² (FFM · St⁻²) in both groups, r = 0.764 (P < 0.05) for the young and r = 0.636 (P < 0.05) for the middle-aged. The relative values of muscle thicknesses to FFM · St⁻² were significantly lower on the abdomen and quadriceps in the middle-aged women than in the young. Thus compared with the young, the middle-aged women have thicker subcutaneous fat thicknesses along the whole body and thinner muscle thicknesses on the trunk and quadriceps regions. Moreover, it appears that in middle-aged women, the relative distribution of subcutaneous fat and muscle thicknesses to FM and FFM, respectively, show disproportionately higher fat stores internally than subcutaneously, and more rapid atrophy of muscle tissues at the anterior sites of the trunk and thigh than at other body sites. Am. J. Hum. Biol. 9:247–255, 1997. © 1997 Wiley-Liss, Inc.