Diagnosis and management of common tinea infections

The estimated lifetime risk of acquiring a dermatophyte infection is between 10 and 20 percent. Recognition and appropriate treatment of these infections reduces both morbidity and discomfort and lessens the possibility of transmission. Dermatophyte infections are classified according to the affected body site, such as tinea capitis (scalp), tinea barbae (beard area), tinea corporis (skin other than bearded area, scalp, groin, hands or feet), tinea cruris (groin, perineum and perineal areas), tinea pedis (feet), tinea manuum (hands) and tinea unguium (nails). To determine the best treatment approach, the physician must consider several factors: (1) the anatomic locations of the infection, (2) the safety, efficacy and cost of treatment options and (3) the likelihood that the patient will comply with treatment. Newer medications in both oral and topical forms, including imidazoles and allylamines, have greatly increased the cure rate for tinea infections. Certain types of tinea may be treated with "pulse" regimens; these innovative therapies lower treatment costs and improve patient compliance.     

Ulcerative colitis with overexpression of p53 preceding overt histological abnormalities of the epithelium

Laser-induced fluorescence of pheophorbide a (Ph-a) was used for in vitro photodynamic imaging (PDI) of a rat pancreatic acinar tumor. A 400 nm excitation induced a 470 nm autofluorescence and a 678 nm dye fluorescence in tumors and their surrounding pancreas 24 h after a 9 mg kg-1 body weight Ph-a intravenous administration. With lower intensities in these blood-rich tumors than in pancreas, Ph-a fluorescence signals are unable to provide tumor images. A dimensionless function (the ratio of Ph-a fluorescence by autofluorescence, called Rt for the tumor and Rp for the pancreas) was used for fluorescence contrast calculation (C = Rt/Rp) between six tumors and their paired pancreas. Among five available laser excitation wave-lengths, only the 355 nm excitation gave a distinctive contrast (C = 1.5). The PDI of six intrapancreatic tumors and their intraperitoneal metastasis and of two control normal pancreas was thus performed ex vivo using a 355 nm excitation source delivered by a tripled Nd:YAG laser and a charged-coupled device camera. Fluorescence images were recorded at 680 nm (dye), 640 nm (background) and 470 nm (autofluorescence) through three corresponding 10 nm width bandpass filters. Computed division for each pixel of Ph-a fluorescence values by autofluorescence generated false color image. In this way, contrasted tumor images were obtained. But in five out of six animals false-positive images were present due to an autofluorescence decrease in some normal pancreatic areas. A 470 nm autofluorescence imaging on the same tumors gave in all cases false-positive image and false-negative in half of the cases. These observations suggest that autofluorescence alone is unable to achieve accurate PDI of pancreatic carcinoma and that using Ph-a as a PDI dye needs strong improvements.     

Detection of undegraded oligonucleotides in living sea urchin eggs by fluorescence resonance energy transfer

A method was investigated for monitoring the integrity of oligonucleotides in solution and in cells using fluorescence resonance energy transfer (FRET) between two different fluorochromes attached to a single oligonucleotide. A 10-meric oligodeoxynucleotide labeled with fluorescein at its 5'-end and with rhodamine X at its 3'-end (F-ODN-R) was used. The oligomer had a specific absorption spectrum with peaks at 497 nm and 586 nm, which corresponded to fluorescein and rhodamine X, respectively. When excited at 494 nm, F-ODN-R had a specific fluorescence spectrum with peaks at 523 nm and 610 nm. The digestion of F-ODN-R with an endonuclease caused the increase in light intensity at 523 nm and the decrease at 610 nm. To examine effects in vivo, living sea urchin eggs were injected with a solution of F-ODN-R and excited with blue light at 470-490 nm. Two fluorescent images, a green image at 520-560 nm and a red image at above 580 nm, were obtained when a single egg was viewed under a fluorescence microscope. Eggs injected with the digested F-ODN-R emitted only green fluorescence. These results indicated that the integrity of oligonucleotides can be estimated in living cells by monitoring FRET after double-labeling of the oligonucleotides with fluorescein and rhodamine X.     

Clinical and experimental studies on composite divitriol infusion in treating tinea manum

OBJECTIVE: To investigate the effect of Composite Divitriol Infusion (CDI) in treating tinea manum and studying its antimycotic action. METHODS: CDI was used to treat 139 patients with tinea manum. The experimental study in vivo was done, scanning electron microscopy (SEM) was used to observe the therapeutical effect of CDI. RESULTS: One hundred and four cases among the 139 patients were cured, 21 were markedly effective, 10 improved and 4 ineffective, the effective rate being 89.9%. Between CDI group and the control group, there was a very significant difference (chi 2 > 12.84, P < 0.005). The antimycotic action of CDI was studied in vitro. Its minimum inhibitory concentrations (MIC) of CDI were about 0.25% for Trichophyton rubrum, and 0.5% for Trichophyton gypseum and Microsporum gypseum. Trichophyton rubrum immersed with CDI show that the mycelia became roughened, deformed and macroconidum became smaller under SEM. CONCLUSION: CDI is valuable in treating tinea manum.     

Prevalence of undetected tinea capitis in a school survey in Spain

From October 1994 to November 1995, a prospective study aiming to detect dermatophytes on the scalp was undertaken in 5000 unselected school children aged between 3 and 16 years (mean age 8.34 years, SD +/- 3.83). Thirty-two (0.64%) had dermatophytes in the scalp, 22. (0.44%) had tinea capitis and 10 were asymptomatic scalp carriers. It is important to point out that 33% of the patients with tinea capitis and 60% of the asymptomatic scalp carriers also had ringworm in other body sites. There was a significantly higher proportion of cases of tinea capitis (P < 0.001)(particularly due to Trichophyton tonsurans, P < 0.001) and of cases of asymptomatic scalp carriers (P < 0.05) (particularly due to Trichophyton tonsurans, P < 0.001) in the immigrant population of African origin. In all the child index cases with positive scalp cultures (tinea capitis and carriers), the household members were studied clinically and mycologically. One child had a body ringworm caused by Microsporum canis. Twelve adults had positive cultures with dermatophytosis (one tinea capitis and eleven body ringworm). Three adult patients were also carriers of dermatophytes in other body sites. Our data indicate a change in the causative agents of tinea capitis seen in Madrid over a 12-month period, with cases due to antropophilic species (T. tonsurans, T. soudanense, M. audouinii and T. violaceum) occurring in the immigrant population from Africa; as a consequence, there is an emergence of T. tonsurans in the Spanish population.     

In vivo laser-induced fluorescence imaging of a rat pancreatic cancer with pheophorbide-a

Laser-induced fluorescence (LIF) of pheophorbide-a (Ph-a) was used for imaging of a rat pancreatic tumor. Using a dimensionless function (the ratio of Ph-a fluorescence by bluish autofluorescence), the fluorescence contrasts between excised tumors and their paired pancreas were investigated up to 48 h after a 9 mg kg-1 Ph-a intravenous administration. Among five tested excitation wavelengths, 355 and 610 nm excitations gave the best distinctive contrasts, both 48 h after dye injection. The LIF imaging of six intrapancreatic tumors and six healthy pancreas was carried out in vivo using two laser excitations: 355 nm (Nd:YAG + tripling) for bluish autofluorescence and 610 nm (rhodamine 6G dye) for reddish autofluorescence and dye emission. Images were recorded through bandpass filters at 470 and 640 nm (autofluorescence) and at 680 nm (dye + autofluorescence) with an intensified charged-coupled device camera. Autofluorescence as Ph-a fluorescence images did not allow accurate LIF diagnosis of pancreatic carcinoma. An image processing, including for each pixel a computed division of Ph-a fluorescence (after subtraction of reddish autofluorescence) by bluish autofluorescence intensity generated poorly contrasted tumor images in five of six and false tumor localization in one of three of the tumor-bearing pancreas. A fitting of the digital 640 nm autofluorescence up to the mean 680 nm fluorescence intensity in pancreas prior to subtraction allowed a safe diagnosis to be made with well-contrasted tumor images. To assess automation ability of the processing, a same fitting coefficient (mean of individual values) was applied. In this way, false-negative (one of six) and false-positive (two of six) images were present in tumor-bearing animals as false-positive in one-half of the controls. A successful standardized procedure was then applied with a normalization of 640 and 680 nm pancreas intensities to a same set threshold prior processing. In opposition to thin-layered hollow organs, such as bronchial tube or digestive tract, LIF imaging of carcinoma inserted in a compact organ is exhausting. The use of a dye excitable in the red wavelength range (610 nm for Ph-a) may partly solve this problem, rendering LIF imaging more accurate and potentially automated.     

Structural studies of the melibiose permease of Escherichia coli by fluorescence resonance energy transfer. I. Evidence for ion-induced conformational change

Further insight into the cosubstrate-induced structural change of the melibiose permease (MelB) of Escherichia coli has been sought by investigating the binding and spectroscopic properties of the fluorescent sugar 2'-(N-5-dimethylaminonaphthalene-1-sulfonyl)aminoethyl 1-thio-beta-D-galactopyranoside (Dns2-S-Gal) and related analogs (Dns3-S-Gal or Dns6-S-Gal with a propyl or hexyl instead of an ethyl linker, respectively) interacting with MelB in membrane vesicles or in proteoliposomes. The three analogs efficiently inhibit melibiose transport and bind to MelB in a sodium-dependent fashion. Their dissociation constants (Kd) are in the micromolar range in the presence of NaCl and an order of magnitude higher in its absence. In the presence of NaCl and Dns2-S-Gal, sample excitation at 335 or 297 nm gives rise to a fluorescent signal at around 465 nm, whereas Dns3-S-Gal or Dns6-S-Gal emits a fluorescence light at 490 or 506 nm, respectively. Detailed study of the Dns2-S-Gal signal elicited by a 297 nm illumination indicates that a tryptophan-mediated fluorescence resonance energy transfer phenomenon is involved in the response. All fluorescence signals below 500 nm are prevented by addition of melibiose in excess, and the kinetic constants describing their dependence on the probe or NaCl concentrations closely correlate with the probe binding constants. Finally, the Dns2-S-Gal signal recorded in sodium-free medium is red shifted by up to 25 nm from that recorded in the presence of NaCl. Taken together, these results suggest (i) that the fluorescence signals below 500 nm arise from Dns-S-Gal molecules bound to MelB, (ii) the presence of a highly hydrophobic environment close to or at the sugar-binding site, the polarity of which increases on moving away from the sugar-binding site, and (iii) that the interaction of sodium ions with MelB enhances the hydrophobicity of this environment. These results are consistent with the induction of a cooperative change of the structure of the sugar-binding site or of its immediate vicinity by the ions.     

Skin and wound infections: an overview

Skin infections are common and may be caused by bacteria, fungi or viruses. Breaks in the skin integrity, particularly those that inoculate pathogens into the dermis, frequently cause or exacerbate skin infections. Bacterial skin infections caused by corynebacteria include erythrasma, trichomycosis axillaris and pitted keratolysis. Staphylococci may cause impetigo, ecthyma and folliculitis. Streptococcal skin infections include impetigo and erysipelas. Human papillomavirus skin infections present as several different types of warts, depending on the surface infected and its relative moisture, and the patterns of pressure. The many dermatomycoses (skin infections caused by fungi or yeasts) include tinea capitis, tinea barbae, tinea cruris, tinea manus, tinea pedis and tinea unguium (onychomycosis). Candidal infections occur in moist areas, such as the vulva, mouth, penis, skinfolds and diaper area. Wounds caused by wood splinters or thorns may result in sporotrichosis. Animal bites may result in complex, serious infections, requiring tetanus and, possibly, rabies prophylaxis in addition to appropriate antibiotic therapy.     

An intermanual advantage for tactual matching

Ultrafast time-gated fluorescence imaging of optically trapped single motile cells is presented. The biflagellar green microalga Haematococcus pluvialis was confined with picoNewton trapping forces in the focal volume of a high numerical aperture objective by near infrared multitraps. Trapping radiation of 100 mW power at the sample was provided by a Nd:YLF laser (1047 nm) operating in the cw mode. Simultaneously, cellular autofluorescence was excited with a 633 nm picosecond 80 MHz laser diode. An ultrafast gated intensified slow scan CCD camera system with a tunable gate width (200 ps-1 ms) and tunable time-delay (0-20 ns) between excitation and detection was used as fluorescence detector. We demonstrate fluorescence imaging of high temporal (sub-ns) and high spatial (sub-microm) resolution and fluorescence lifetime determination of intracellular autofluorescence based on chlorophyll excitation. Exposure to the herbicide DCMU resulted in an increase of fluorescence intensity and lifetime by 250% and 150%, respectively.     

Enzymatic, fluorometric assay of alpha-amylase in serum

An enzymatic, fluorometric method for kinetic assay of serum alpha-amylase (1,4alpha-D-glucan 4-glucanohydrolase, EC 3.2.1.1) is described. A soluble starch is used as substrate, in tris(hydroxymethyl)methylamine buffer. All measurements are made in Pyrex cuvettes at 37 degrees C, with a reaction volume of 1.16 ml. The assay is based on the following reaction sequence: (see article) The rate of appearance of fluorescence of NADH (lambdaex = 365 nm, lambdaem = 460 nm), developed in the indicator reaction (4), is measured and equated to the activity of alpha-amylase in serum. A calibration plot of the change of fluorescence per min vs. enzyme concentration shows a good proportionality in the range of 0.50-5.0 kU/liter.     

水杨基荧光酮荧光法测定羟自由基的探讨

建立了一种新的测定Fenton反应所产生的羟自由基的方法,经过条件的研究,得出最佳实验条件,同时,通过清除率实验反证了该方法的可靠性,利用顺磁共振法测定SAF加入前后的波谱变化来进一步证实该方法的正确性,化学测定过程均在国产仪器下完成。     

The Darwin is in the details.

Comments on the article by A. H. Eagly and W. Wood (see record 1999-05337-002) which examined the origins of sex differences in human behavior. Eagly and Wood argued that social structural theory can explain the origin of psychological sex differences. The present authors suggest that evolutionary models of sex differences are based on a much broader foundation that Eagly and Wood imply. They note that Eagly and Wood misconstrued previous age preference findings as supporting the "common knowledge" that men prefer younger women. Eagly and Wood also showed that as societies approach gender equality in resource access, some sex differences in mate preferences decrease; however, as the current authors note, evolved mechanisms are not environmentally insensitive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High resolution multichannel fluorescence detection for capillary electrophoresis. Application to multicomponent analysis

A wavelength-resolved fluorescence detector for laser-induced fluorescence detection in capillary electrophoresis (CE) is described that uses a charge injection device (CID) array detector Post-column fluorescence detection occurs using a sheath flow cell. The limit of detection for fluorescein is 4.8 x 10(-11) M (29,000 molecules), the spectral resolution is 0.56 nm/pixel, and the spectrograph/CID monitors a 250 nm spectrum throughout the 250-875 nm range. Custom array readout, data manipulation and data processing methods are described to convert wavelength/spatial CID images into electropherograms. The application of the system to characterizing bilirubins in human serum is described, demonstrating the ability to match electrophoretic peaks to standards using spectral information.     

Time-resolved fluorescence studies of dityrosine in the outer layer of intact yeast ascospores

The (time-resolved) fluorescence properties of dityrosine in the outermost layer of the spore wall of Saccharomyces cerevisiae were investigated. Steady-state spectra revealed an emission maximum at 404 nm and a corresponding excitation maximum at 326 nm. The relative fluorescence quantum yield decreased with increasing proton concentration. The fluorescence decay of yeast spores was found to be nonexponential and differed pronouncedly from that of unbound dityrosine in water. Analysis of the spore decay recorded at lambda ex = 323 nm and lambda em = 404 nm by an exponential series (ESM) algorithm revealed a bimodal lifetime distribution with maxima centered at tau 1C = 0.5 ns and tau 2C = 2.6 ns. The relative amplitudes of the two distributions are shown to depend on the emission wavelength, indicating contributions from spectrally different dityrosine chromophores. On quenching the spore fluorescence with acrylamide, a downward curvature of the Stern-Volmer plot was obtained. A multitude of chromophores more or less shielded from solvent in the spore wall is proposed to account for the nonlinear quenching of the total spore fluorescence. Analysis of the fluorescence anisotropy decay revealed two rotational correlation times (phi 1 = 0.9 ns and phi 2 = 30.6 ns) or a bimodal distribution of rotational correlation times (centers at 0.7 ns and 40 ns) when the data were analyzed by the maximum entropy method (MEM). We present a model that accounts for the differences between unbound (aqueous) and bound (incorporated in the spore wall) dityrosine fluorescence. The main feature of the photophysical model for yeast spores is the presence of at least two species of dityrosine chromophores differing in their chemical environments. A hypothetical photobiological role of these fluorophores in the spore wall is discussed: the protection of the spore genome from mutagenic UV light.     

Anisotropy of photosynthetic membranes and the degree of fluorescence polarization

The degree of fluorescence polarization, P, of unoriented and magnetically oriented spinach chloroplasts as a function of excitation (400-680 nm) and emission wavelengths (675-750 nm) is reported. For unoriented chloroplasts P can be divided into two contributions, PIN and PAN. The latter arises from the optical anisotropy of the membranes which is due to the orientation with respect to the membrane plane of pigment molecules in vivo. The intrinsic polarization PIN, which reflects the energy transfer between different pigment molecules and their degree of mutual orientation, can be measured unambiguously only if (1) oriented membranes are used and the fluorescence is viewed along a direction normal to the membrane planes, and (2) the excitation is confined to the Qy (approximately 660-680 nm) absorption band of chlorophyll in vivo. With 670-680 nm excitation, values of P using unoriented chloroplasts can be as high as +14%, mostly reflecting the orientational anisotropy of the pigments. Using oriented chloroplasts PIN is shown to be +5+/-1%. The excitation wavelength dependence studies of PIN indicate that the carotenoid and chlorophyll Qy transition moments tends to be partially oriented with respect to each other on a local level (within a given photosynthetic unit or its immediate neighbors).     

Fluoresceinyl-ethylenediamine-ouabain detects an acidic environment in the cardiac glycoside binding site of Na+/K+-ATPase

To probe the pH value in the microenvironment of the cardiac glycoside-binding site of Na+/K+-ATPase, pH-sensitive fluorescent derivatives of ouabain were synthesized. The fluoresceinyl derivative of ethylenediamino-ouabain (FEDO) had a pKs of 6.0 and showed a H+-dependent fluorescence change, when its ratio of excitation at 490 nm/450 nm was recorded at 530 nm. Binding of FEDO inactivated Na+/K+-ATPase at 37 degrees C and pH 7.25 in a slow time-dependent process under the conditions of backdoor phosphorylation with k(on) of 891 s(-1) M(-1). The complex dissociated with k(on) of 0.35 x 10(-3) s(-1) resulting in a Kd value of 0.4 microM for the FEDO x enzyme complex. Binding of FEDO was associated with a decrease of the excitatory fluorescence ratio at 490 nm/450 nm which could be used to convert this change into a pH value. A pH value of 5.1 +/- 0.2 was calculated to exist in the microenvironment of the FEDO x enzyme complex. This pH value was independent of the pH of the incubation medium used to form the FEDO x enzyme complex. Analysis of the accessibility of the fluorophore in the FEDO x enzyme complex to the dynamic quencher potassium iodide detected a decrease of the Stern-Volmer constant from 6.2 mM(-1) (free FEDO) to 1.5 mM(-1) (FEDO x enzyme complex) indicating thereby a limited accessibility of the fluorophore to anions. Analysis of the microenvironment of the fluorescein residue of the FEDO x enzyme complex by measurements of the anisotropy and the fluorescence half-life time revealed that both processes differed significantly when H2O was replaced by D2O. We conclude, therefore, that a pH of 5.1 +/- 0.2 exists in the vicinity of ouabain that is hidden in the depth of the receptor site when the ouabain receptor complex has been formed.     

Emergence of order in visual system development

There has been a recent increase in the frequency of skin mycoses, coupled with changes in the epidemiology and distribution of the species responsible. Periodic epidemiological analyses of these disease are thus required to ensure their efficacious control. Hair fragments, skin scrapings, specimens from vesicles and blisters and nail parings were seeded on Petri dishes loaded with Sabouraud or Mycosel agar, supplemented with chloramphenicol and with chloramphenicol plus cycloheximide respectively. Parts of each specimen were also mounted in 10% potassium hydroxide for examination under the microscope. Yeasts prevailed over dermatophytes. Microsporum canis was the most frequent dermatophyte, followed by Trichophyton rubrum, T. mentagrophytes and Epidermophyton floccosum. Tinea corporis was the most common mycosis, followed by tinea unguis, tinea capitis and tinea pedis. Men were chiefly bearers of tinea cruris and tinea pedis, women of tinea corporis, and children and teenagers of tinea capitis. Some examples of the transmission of infection through interhuman contact, via animals and from the soil are also presented.     

Autofluorescence in normal and malignant human oral tissues and in DMBA-induced hamster buccal pouch carcinogenesis

Light-induced fluorescence spectroscopy was conducted on human oral malignant and normal tissues. Under 330-nm excitation wavelength, significant differences in fluorescence intensity were observed around 380- and 460-nm emission. Furthermore, 7,12-dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis in hamster buccal pouch was investigated to elucidate whether similar alterations of fluorescence spectroscopy occurred during the development of squamous cell carcinoma. Similar to the spectral profiles of human oral malignant and normal tissues, the most intense fluorescence peaks in the pouches occurred at 380 nm and 460 nm emission under 330 nm excitation wavelength. At 380 nm emission, the fluorescence intensity of normal pouch mucosa was stronger than those of DMBA-treated abnormal tissues at different stages of carcinogenesis. However, at 460 nm emission, the fluorescence intensity of DMBA-treated tissues was not only stronger than that of normal pouch mucosa but also shifted to 470 nm. These results suggest that under 330 nm excitation wavelength fluorescence spectroscopy may be useful for the detection of oral malignant lesions.     

The cyanobacterium Spirulina platensis contains a long wavelength-absorbing pigment C738 (F76077K) at room temperature

Spirulina platensis is a cyanobacterium which usually lives under high-light conditions. Nonetheless, it is thought to contain the most red-shifted antenna pigment of all known Chl a-containing phototrophic organisms, as shown by its 77 K fluorescence peaking at 760 nm. To exclude preparation artifacts and to exclude the possibility that long wavelength-absorbing pigments form only when the temperature is lowered to 77 K, we carried out experiments with whole cells at room temperature. The combined analysis of stationary absorption and fluorescence spectra as well as fluorescence induction and time-resolved fluorescence decays shows that the pigment responsible for the 77 K fluorescence at 760 nm (i) has the oscillator strength of approximately one Chl a molecule, (ii) absorbs maximally at 738 nm (), (iii) is present only in the antenna system of PS I, (iv) participates in light collection, and (v) does not entail a low photochemical quantum yield. Other, more abundant but less red-shifted Chl a antenna pigments lead to a significantly larger absorption cross section of the photosynthetic unit of PS I above 700 nm compared to units that would not possess these long wavelength-absorbing pigments. These results support the hypothesis that the physiological role of long wavelength-absorbing pigments is to increase the absorption cross section at wavelengths of >700 nm when in densely populated mats the spectrally filtered light is relatively more intense at these wavelengths [Trissl, H.-W. (1993) Photosynth. Res. 35, 247-263].     

Fluorescence spectroscopy of the longwave chlorophylls in trimeric and monomeric photosystem I core complexes from the cyanobacterium Spirulina platensis

The organization and interaction of chlorophylls (Chl) and the kinetics of the energy transfer in the core antenna of photosystem I (PSI) trimeric and monomeric complexes, isolated from Spirulina platensis with Triton X-100 have been studied by stationary and time-resolved fluorescence. At 295 K both complexes show an unusually intense long-wavelength emission band with prominent peaks at 730 nm (trimers) or 715 nm (monomers), whose intensity is independent of the redox state of P700. A broad band extending from 710 to 740 nm in the absorption and fluorescence excitation spectra of trimers also indicates the existence of the longwave Chls at 295 K. The 77 K fluorescence emission of PSI trimers frozen after addition of dithionite under illumination (P700 and the PSI acceptor side reduced) shows an intense band at 760 (F760) and a smaller one at 725 nm (F725); when P700 is oxidized, the intensity of F760 decreases about 15 times. In the 77 K spectrum of monomers only F725 is present in the longwave region, and its intensity does not depend on the redox state of P700. Bands of Chls with maxima near 680, 710, and 738 nm were found in the 77 K excitation spectrum of trimers, and bands near 680 and 710 nm were seen in the spectrum of monomers. Five spectrally different red Chl forms in PSI trimers and three red Chl in monomers have been resolved by deconvolution of their 77 K absorption spectra. The difference absorption spectrum, trimers-minus-monomers, shows that the appearance of the 735 nm band in trimers is accompanied by a decrease of 708, 698, and 688 nm bands present in monomers. The reversible changes of F760 intensity of Spirulina membranes as a result of their salt treatment confirm the idea that the most longwave Chl form originates from an interaction of Chls bound to different monomeric PSI subunits forming the trimer. The time-resolved fluorescence spectra of PSI trimers and monomers, measured at 287 K in the region 680-770 nm, are substantially different, although a set of similar lifetimes (9, approximately 30, approximately 66, and 1400-2200 ps) was necessary for a good fit. No effect of P700 redox state was observed on the fluorescence kinetics of both complexes at 287 K.