Relative pathogenicity of Candida tropicalis in rat tongue mucosa

The potential ofC. tropicalis to colonize and infect rat tongue mucosa was demonstrated. Thirty female Sprague-Dawley rats were infected orally with three different strains ofC. tropicalis. The animals were killed one and three weeks following the inoculation and sections of their tongue were stained with hematoxylin-eosin and Grocott stain. Histological changes were observed in the group of animals killed one week after inoculation and infected withC. tropicalis strain isolated from the crural ulcer of a diabetic patient. The most important finding was acute purulent myositis with the formation of abscesses. The myositis was local without signs of spreading to the surrounding tissue. Epithelium-penetrating hyphae observed in the Grocott-stained sections were relatively fewer and more sparsely distributed.     

Chromosomal polymorphism in natural populations of Drosophila pavani

Summary D. pavani Brncic 1957, is a neotropical species found in Chile and in a part of Argentina along the eastern slope of the Andes. The present paper describes the mitotic and salivary gland chromosomes of this species and gives a composite map of the Standard gene arrangement.Natural populations ofD. pavani are polymorphic with respect to the gene orders in their chromosomes. The observed variations in the gene arrangements are due to complex included and overlapping paracentric inversions. In none of the populations or in the crosses studied were found the hypothetical intermediate steps needed for the establishment of the phylogeny of the gene orders present in nature.The qualitative and quantitative data on the distribution and frequency of inversions show no pronounced geographic variations. The high incidence of inversion heterozygotes and the absence of the intermediate steps between the gene arrangements found in nature, seem to indicate an adaptive nature of the polymorphism observed inD. pavani This work has been supported in part by a grant from the Rockefeller Foundation.     

Electroencephalographic characteristics of cognitive-specific alerting attention in verbal learning: I. Characteristics of EEG local synchronization

The EEG was recorded in 19 standard derivations in 88 students in the following states: rest with the eyes open, memorization (learning) of bilingual verbal semantic pairs (Latin and Russian), and retrieval (check) of the learned information. In order to calculate the mean heart rate (HR) in each state, the electrocardiogram was recorded. The subjective difficulty of task performance was assessed. Statistical comparison of the spectral power estimates in these states for frequency bands θ (4–7 Hz), α₁ (7–10 Hz), α₂ (10–13 Hz), β₁ (13–18 Hz), β₂ (18–30 Hz), and γ (30–40 Hz) demonstrated a number of significant differences in the EEG absolute power (local synchronization) between the states reproducible in subgroups. Comparison of the states of memorization and retrieval showed that, in the state of memorization, the EEG power in the γ, β₂, and θ bands was significantly lower throughout the cortical surface. Comparison of the active states with the reference state of rest showed that, in both active states, changes in the EEG power were of the same direction in the majority of the frequency bands (an increase in the θ, β₂, and γ bands and a decrease in the α₂ band) except α₁, in which memorization was predominantly accompanied by a decrease in the power, whereas retrieval was associated with an increase. No significant differences were found between the states of memorization and retrieval in the HR or the subjective estimate of task difficulty. The results can be interpreted as a reflection of cognitive-specific forms of general preparatory attention.     

Electroencephalographic characteristics of cognitive-specific attention in verbal learning—II: General characteristics of EEG spatial synchronization

Electroencephalograms (EEGs) were recorded in 19 standard derivations in 88 subjects (students) in states of: rest with the eyes open; memorization (learning) of verbal bilingual semantic pairs (Latin and Russian); and recollection (control) of the memorized information. Estimates of EEG coherence in these states were compared using statistical methods for the frequency bands θ, α₁, α₂, β₁, β₂, and γ. The results of this comparison showed that transition from the state of rest to those of memorization and recollection was accompanied by numerous changes in coherence in all the frequency bands. These changes varied in intensity and embrace practically the entire convexital cerebral cortex. Decrease in EEG coherence was predominant during the transition to the memorization state in various frequency bands, whereas during the transition from the rest state to that of recollection, EEG coherence increased in most of the frequency bands except for the band α₂. The reproducibility of this pattern of changes in EEG coherence is confirmed by the results in the subgroups formed by randomly subdividing the subjects into two groups. We think that the observed intense rearrangement of the spatial synchronization of the cortex electrical activity reflects the reorganization of the functional systems of neuronal ensembles to provide efficient memorization and recollection, respectively.     

Electromyogram of pericranial muscles in frequency bands β and γ comparing various cognitive and emotional states

Results of comparison of power of electromyogram (EMG) of six pericranial muscles in electroencephalographic frequency bands β₁, β₂ and γ are presented corresponding to performances of the tasks bound to inductions of affective experiences. The external induction was implemented by means of presentation of images and the internal induction by means of autobiographical memoirs revived. The tasks were focused on an induction of affective experiences with different emotional valences—positive, negative and neutral. The EMG was derived, registered and processed by means of computer electroencephalography techniques. Self-assessments of signs and intensities of experienced emotions were recorded as well. The study involved two groups of healthy subjects—students-actors (N = 39), and students of other specialties (N = 32). Statistically reliable, reproducible and diverse differences of mean EMG power of the pericranial muscles took place in comparisons of psychophysiological states with different valences of emotions, and certain differences in comparisons of states without expressed emotional differences, but differing in the direction of attention took place also. Therefore it is obviously necessary for an assessment of a degree of muscular contamination in records of high-frequency scalp electroencephalograms (EEG) to supplement psychophysiological EEG methods with EMG registration and statistical analysis and to do such registration for several facial muscles.     

Comprehensive analysis of expression and function of 51 sarco(endo)plasmic reticulum Ca2+-ATPase mutants associated with Darier disease

We examined possible defects of sarco(endo)plasmic reticulum Ca2+-ATPase 2b (SERCA2b) associated with its 51 mutations found in Darier disease (DD) pedigrees, i.e. most of the substitution and deletion mutations of residues reported so far. COS-1 cells were transfected with each of the mutant cDNAs, and the expression and function of the SERCA2b protein was analyzed with microsomes prepared from the cells and compared with those of the wild type. Fifteen mutants showed markedly reduced expression. Among the other 36, 29 mutants exhibited completely abolished or strongly inhibited Ca2+-ATPase activity, whereas the other seven possessed fairly high or normal ATPase activity. In four of the aforementioned seven mutants, Ca2+ transport activity was significantly reduced or almost completely lost, therefore uncoupled from ATP hydrolysis. The other three were exceptional cases as they were seemingly normal in protein expression and Ca2+ transport function, but were found to have abnormalities in the kinetic properties altered by the three mutations, which happened to be in the three DD pedigrees found by us previously (Sato, K., Yamasaki, K., Daiho, T., Miyauchi, Y., Takahashi, H., Ishida-Yamamoto, A., Nakamura, S., Iizuka, H., and Suzuki, H. (2004) J. Biol. Chem. 279, 35595-35603). Collectively, our results indicated that in most cases (48 of 51) DD mutations cause severe disruption of Ca2+ homeostasis by the defects in protein expression and/or transport function and hence DD, but even a slight disturbance of the homeostasis will result in the disease. Our results also provided further insight into the structure-function relationship of SERCAs and revealed critical regions and residues of the enzyme.     

Anthropometric parameters as predictors for iliopsoas muscle strength in healthy girls and in girls with adolescent idiopathic scoliosis

In this study iliopsoas muscle strength was measured by portable dynamometer and it was explored to what extent independent predictors (age, body weight, body height and body mass index) affect iliopsoas strength in healthy subjects and in subjects with adolescent idiopathic scoliosis. The study population was consisted of 183 girls (90 healthy girls and 93 girls with adolescent idiopathic scoliosis). Student t test analysis showed no differences in maximal voluntary isometric contraction between healthy girls and girls with scoliosis. Independent variables predicted significantly iliopsoas strength in healthy group (r=0.96, p<0.01) and in scoliosis group (r=0.94, p<0.001). Separate analysis with respect to types of scoliosis demonstrated that independent variables significantly predict iliopsoas strength in right thoracic (r=0.97, p<0.01), left thoracic (r=0.98, p=0.004), right thoracic lumbar (r=0.97, p<0.01) and left lumbar (r=0.96, p<0.01) scoliosis subgroups. In healthy girls iliopsoas strength was mostly predicted by body weight, followed by body height and body mass index. In girls with scoliosis body weigth was the strongest predictor of iliopsoas strength and was followed by curvature angle degree.     

Multiple and distinct effects of mutations of Tyr122, Glu123, Arg324, and Arg334 involved in interactions between the top part of second and fourth transmembrane helices in sarcoplasmic reticulum Ca2+-ATPase: changes in cytoplasmic domain organization during isometric transition of phosphoenzyme intermediate and subsequent Ca2+ release

We explored, by mutational substitutions and kinetic analysis, possible roles of the four residues involved in the hydrogen-bonding or ionic interactions found in the Ca2+-bound structure of sarcoplasmic reticulum Ca2+-ATPase, Tyr(122)-Arg(324), and Glu(123)-Arg(334) at the top part of second transmembrane helix (M2) connected to the A domain and fourth transmembrane helix (M4) in the P domain. The observed substitution effects indicated that Glu(123), Arg(334), and Tyr(122) contributed to the rapid transition between the Ca2+-unbound and bound states of the unphosphorylated enzyme. Results further showed the more profound inhibitory effects of the substitutions in the M4/P domain (Arg(324) and Arg(334)) upon the isomeric transition of phosphorylated intermediate (EP) (loss of ADP sensitivity) and those in M2/A domain (Tyr(122) and Glu(123)) upon the subsequent processing and hydrolysis of EP. The observed distinct effects suggest that the interactions seen in the Ca2+-bound structure are not functionally important but indicate that Arg(334) with its positive charge and Tyr(122) with its aromatic ring are critically important for the above distinct steps. On the basis of the available structural information, the results strongly suggest that Arg(334) moves downward and forms new interactions with M2 (likely Asn(111)); it thus contributes to the inclination of the M4/P domain toward the M2/A domain, which is crucial for the appropriate gathering between the P domain and the largely rotated A domain to cause the loss of ADP sensitivity. On the other hand, Tyr(122) most likely functions in the subsequent Ca2+-releasing step to produce hydrophobic interactions at the A-P domain interface formed upon their gathering and thus to produce the Ca2+-released form of EP. During the Ca2+-transport cycle, the four residues seem to change interaction partners and thus contribute to the coordinated movements of the cytoplasmic and transmembrane domains.     

Roles of Tyr122-hydrophobic cluster and K+ binding in Ca2+ -releasing process of ADP-insensitive phosphoenzyme of sarcoplasmic reticulum Ca2+ -ATPase

Tyr(122)-hydrophobic cluster (Y122-HC) is an interaction network formed by the top part of the second transmembrane helix and the cytoplasmic actuator and phosphorylation domains of sarcoplasmic reticulum Ca(2+)-ATPase. We have previously found that Y122-HC plays critical roles in the processing of ADP-insensitive phosphoenzyme (E2P) after its formation by the isomerization from ADP-sensitive phosphoenzyme (E1PCa(2)) (Wang, G., Yamasaki, K., Daiho, T., and Suzuki, H. (2005) J. Biol. Chem. 280, 26508-26516). Here, we further explored kinetic properties of the alanine-substitution mutants of Y122-HC to examine roles of Y122-HC for Ca(2+) release process in E2P. In the steady state, the amount of E2P decreased so that of E1PCa(2) increased with increasing lumenal Ca(2+) concentration in the mutants with K(0.5) 110-320 microm at pH 7.3. These lumenal Ca(2+) affinities in E2P agreed with those estimated from the forward and lumenal Ca(2+)-induced reverse kinetics of the E1PCa(2)-E2P isomerization. K(0.5) of the wild type in the kinetics was estimated to be 1.5 mM. Thus, E2P of the mutants possesses significantly higher affinities for lumenal Ca(2+) than that of the wild type. The kinetics further indicated that the rates of lumenal Ca(2+) access and binding to the transport sites of E2P were substantially slowed by the mutations. Therefore, the proper formation of Y122-HC and resulting compactly organized structure are critical for both decreasing Ca(2+) affinity and opening the lumenal gate, thus for Ca(2+) release from E2PCa(2). Interestingly, when K(+) was omitted from the medium of the wild type, the properties of the wild type became similar to those of Y122-HC mutants. K(+) binding likely functions via producing the compactly organized structure, in this sense, similarly to Y122-HC.     

In vitro propagation of Fibigia triquetra (DC.) Boiss., a rare stenoendemic species

A rapid clonal propagation method for Fibigia triquetra (DC.) Boiss. (Brassicaceae), a rare Croatian stenoendemic species, has been developed. Shoots originated from aseptically germinated seeds were used for culture initiation. The highest multiplication rate of 9.2 shoots per explant was achieved in a 4-weeks-culture period in the third subculture on half strength Murashige and Skoog medium supplemented with 0.5 μM 6-benzylaminopurine and 2.9 μM gibberellic acid. Excised shoots were rooted best with addition of 8.6 μM indole-3-butyric acid on the same basal medium. Rooted plantlets were successfully transferred to potting soil and acclimatized to outdoor conditions. This revised version was published online in June 2006 with corrections to the Cover Date.