Molecular cloning and functional characterization of a histidine decarboxylase from Staphylococcus capitis

AIMS

Histamine intoxication is probably the best known toxicological problem of food-borne disease. A histamine-producing Staphylococcus capitis strain has been isolated from a cured meat product. The aim of this study was to gain deeper insights into the genetic determinants for histamine production in Staph. capitis.

METHODS AND RESULTS

The nucleotide sequence of a 6446-bp chromosomal DNA fragment containing the hdcA gene encoding histidine decarboxylase (HDC) has been determined in Staph. capitis IFIJ12. This DNA fragment contains five complete and two partial open reading frames. Putative functions have been assigned to gene products by sequence comparison with proteins included in the databases. The hdcA gene has been expressed in Escherichia coli resulting in HDC activity. The presence of a functional promoter (Phdc) located upstream of hdcA has been demonstrated. Insertion of the histamine biosynthetic locus in Staph. capitis seems to be associated with a noticeable genome reorganization.

CONCLUSIONS

Among the staphylococcal species analysed in this study only Staph. capitis strains produce histamine. The hdcA gene cloned from Staph. capitis encodes a functional HDC that produce histamine from the amino acid histidine.

SIGNIFICANCE AND IMPACT OF THE STUDY

The identification of the DNA region involved in histamine production in Staph. capitis will allow further work in order to avoid histamine production in foods.

[Prevalence of metallo-beta-lactamase in carbapenem resistant Pseudomonas aeruginosa at a university hospital of Buenos Aires City]

The present study was conducted to estimate the prevalence of metallo-beta-lactamases in 91 consecutive carbapenem resistant Pseudomonas aeruginosa isolates, recovered from inpatients at Hospital de Clínicas in Buenos Aires. Both, phenotypic and genotypic methods detected the presence of carbapenemases in 10 (11%) isolates, corresponding to VIM-11 in 7/10 and VIM-2 in the others. Codifying genes were all included in class 1 integrons, upstream genes coding for aminoglycoside modifying enzymes. One hundred percent sensitivity and specificity was achieved by the metallo-beta-lactamases phenotypic screening method using EDTA (1 micromol) disks in the Pseudomonas aeruginosa isolates included in this study. Sensitivity to aztreonam in carbapenem resistant isolates was suspicious of the presence of these enzymes.

[Are the tools recommended by ASPEN and ESPEN comparable for assessing the nutritional status?]

INTRODUCTION

[corrected] There is no "gold standard" for identification of malnutrition. The ASPEN board of directors (2002) suggest the subjective global assessment (SGA) and ESPEN (2002) recommend the nutritional risk screening-2002 (NRS-2002) to detect the prevalence of malnutrition.

AIMS

This cross-sectional study aims (1) to assess the prevalence of malnutrition on admission and (2) to know association between two tools used to evaluate nutritional risk.

MATERIAL AND METHODS

135 patients (42.2% women and 58.8% men, 62.1 +/- 14.4 years) are studied at admission. Different parameters are assessed to evaluate nutritional state. Patient's energy requirements (Harris Benedict x Long's factor) and energy intake, calculated as 24 h-recall, are compared. The prevalence of malnutrition is assessed with two screening tools: SGA and NRS-2002.

RESULTS

42.2% of the patients had lost more than 5% body weight and 39.3% had an intake lower than required at admission. The prevalence of malnutrition is 40.7 and 45.1/100 patients admitted at hospital, if SGA or NRS-2002 are used, respectivility. There is strong agreement between results of two nutritional assessment methods (p = 0.000). Serum albumin and protein concentrations and linfocytes count are less in the malnourished patients.

CONCLUSIONS

The prevalence of malnutrition is elevated. In clinical practice, both methods could be used to identify patients at nutritional risk, but the NRS-2002 is a less subjective method.

Liver Transplantation at the Cuban Center for Medical and Surgical Research

From July 4, 1999, when a liver transplantation program was started in Cuba, to October 2003, 66 procedures had been performed in 60 patients. The most frequent reason was cirrhosis caused by hepatitis C virus (29%), and alcoholic cirrhosis (22%). Two patients received simultaneous liver-kidney transplants. Half of the patients were men. Patient ages ranged from 12 to 62 years; the average surgical time was 6 hours; and cold ischemia time was 4 to 14 hours. The average blood consumption was 2033 mL; 2900 mL of plasma and 8 units of platelets were used in 7 cases. Immunosuppression was mainly cyclosporine (Neoral), mycophenolate mofetil or azathioprine, and prednisone. Acute cellular rejections were treated in almost all cases with 3 doses of methylprednisolone. The most frequent complications were biliary (24%), hepatic arterial thrombosis (12%), post-surgical bleeding (10%), acute cellular rejection (24%), and ductopenic rejection (2%). The overall 1-year survival rate was 73.7%.

Accumulation of astaxanthin and lutein in Chlorella zofingiensis (Chlorophyta)

When grown photoautotrophically, Chlorella zofingiensis strain CCAP 211/14 accumulates a significant amount of valuable carotenoids, namely astaxanthin and lutein, of increasing demand for use as feed additives in fish and poultry farming, as colorants in food, and in health care products. Under standard batch-culture conditions, this microalgal strain exhibits high values of both growth rate (about 0.04 h(-1)) and standing cell population (over 10(11) cells l(-1), or 7 g dry weight l(-1)). Lutein, in a free (unesterified) form, was the prevalent carotenoid during early stages of cultivation (over 0.3 pg cell(-1), equal to 4 mg g(-1) dry weight, or 20 mg l(-1) culture), whereas esterified astaxanthin accumulated progressively, to reach a maximum (over 0.1 pg cell(-1), equal to 1.5 mg g(-1) dry weight, or 15 mg l(-1) culture) in the late stationary phase. A differential response of lutein and astaxanthin accumulation was also recorded with regard to the action of some environmental and nutritional factors. C. zofingiensis CCAP 211/14 represents a unique model system for analyzing the differential regulation of the levels of primary (lutein) and secondary (astaxanthin) carotenoids. Relevant also from the biotechnological viewpoint, this photosynthetic organism, with outstanding attributes for fast photosynthetic growth and carotenoid accumulation, might prove most valuable for its application to the mass production of either or both lutein and astaxanthin.

Phosphate solubilizing bacteria and their role in plant growth promotion

The use of phosphate solubilizing bacteria as inoculants simultaneously increases P uptake by the plant and crop yield. Strains from the genera Pseudomonas, Bacillus and Rhizobium are among the most powerful phosphate solubilizers. The principal mechanism for mineral phosphate solubilization is the production of organic acids, and acid phosphatases play a major role in the mineralization of organic phosphorous in soil. Several phosphatase-encoding genes have been cloned and characterized and a few genes involved in mineral phosphate solubilization have been isolated. Therefore, genetic manipulation of phosphate-solubilizing bacteria to improve their ability to improve plant growth may include cloning genes involved in both mineral and organic phosphate solubilization, followed by their expression in selected rhizobacterial strains. Chromosomal insertion of these genes under appropriate promoters is an interesting approach.

High torque ultrasonic motors for hand prosthetics: current status and trends

This paper presents the work carried out at the Instituto de Automática Industrial, in the framework of the EU MANUS project and with the co-operation of the Katholieke Universiteit of Leuven, to develop a specifically designed TWUM for driving our prototype of hand prosthesis. The application of TWUM to prosthetic devices has clear advanteges, namely, noiseless operation, self-braking drive, high torque and low speed characteristics. Here we analyse main actuation advantages, point out main drawbacks of this technology and describe our research in the area of specific design of TWUM for high torque actuation, improved control characteristics and enhanced overall performance. We intend to provide a concurrent approach to the overall actuator design involving electronics, mechanical design as well as improved control strategies having in mind the prosthetic application.

Broad band spectral measurements of EEG during emotional tasks

Broad band spectral measurements were calculated on EEG recordings of 40 healthy male university students during emotional tasks using the emotion induction technique. Emotional stimuli were sentences with positive valence (joy of love), with negative valence (frustration) and neutral situation. Broad band measurements showed that delta and beta bands reflected better the differences by emotional state. Hemispheric differences associated to emotional states were obtained only for mean frequency data. Higher delta frequencies at left frontopolar, right frontal, parietal and temporal and higher beta frequencies at left frontotemporal and temporal were related to love. Meanwhile higher delta frequencies especially at left frontopolar and temporal regions and lower beta frequencies at midline frontal (Fz) and central (Cz) leads were associated to frustration. These findings suggest that narrow band measurements may reflect more efficiently EEG changes during emotional tasks.

Expression of a mineral phosphate solubilizing gene from Erwinia herbicola in two rhizobacterial strains

A genetic construction was carried out using the broad host range vector pKT230 and plasmid pMCG898, which encodes the Erwinia herbicola pyrroloquinoline quinone (PQQ) synthase, a gene involved in mineral phosphate solubilization (mps). The final construction was transformed and expressed in Escherichia coli MC1061, and the recombinant plasmids were transferred to Burkholderia cepacia IS-16 and Pseudomonas sp. PSS recipient cells by conjugation. Clones containing recombinant plasmids produced higher clearing halos in plates with insoluble phosphate as the unique (P) source, in comparison with those of strains without plasmids, demonstrating the heterologous expression of the E. herbicola gene in the recipient strains. This genetic manipulation allowed the increase in mps ability of both strains, enhancing their potentialities as growth promoters of agricultural crops. These results represent the first report on the application of the recombinant DNA methodology for the obtaining of improved phosphate solubilizing ability from rhizobacterial strains for biofertilization purposes.

The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid

In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50%) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.

Left atrial reduction and mitral valve surgery: the "functional-anatomic unit" concept

The desired outcome for patients undergoing mitral valve surgery includes both good function of the mitral valve, and preservation and restoration of sinus rhythm. To achieve such an outcome, we evolved the concept of the left atrium and mitral valve as a "functional anatomic unit." In this report, we describe a technique for reduction in left atrial size, isolation of the pulmonary veins, and amputation of the left atrial appendage in combination with mitral valve repair. We performed such a procedure in 4 patients, with rheumatic mitral valve disease and chronic atrial fibrillation, with restoration of good valve function and sinus rhythm at 16 to 20 months after surgery.

Lutein production by Muriellopsis sp. in an outdoor tubular photobioreactor

The effect of dilution rate, mixing and daily solar cycles on lutein and biomass productivity of the green unicellular alga Muriellopsis sp. has been studied, throughout the year, in an outdoor tubular photobioreactor. Highest productivity values, for both lutein (about 180 mg m(-2) per day) and biomass (about 40 g (dry weight) m(-2) per day) were achieved on May and July. Values for the optimal dilution rate varied, being lower in May (0.06 h(-1)) than in November (0.09 h(-1)). Similar values for photosynthetic efficiency (about 4%) were recorded throughout the year, indicating that optimization of culture conditions was achieved for each experimental period. Along the daily solar cycle, there was a fast increase of lutein content of Muriellopsis sp. in response to irradiance during the early hours of daytime, with maximal lutein content (about 6 mg (g dry weight)(-1)) being recorded at noon, and decreasing slowly, thereafter. An increase in cell growth was observed following the establishment of maximum lutein/chlorophyll ratio, which might indicate a role for lutein in protecting cells from photodamage.

A study of the electrospray ionisation and ion-trap fragmentation of [M - H](-) ions of new 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazin-2-thiones

The electrospray ionisation (ESI) in negative mode of the pharmacologically significant 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazin-2-thiones, and their subsequent fragmentations using an ion-trap mass spectrometer, have been investigated. Experiments on sequential product ion fragmentations (MS(n)) were performed in order to elucidate the degradation pathways for these compounds. The data presented show that the fragmentation of the even-electron [M - H](-) ions could proceed through an internal nucleophilic substitution displacement. Decarboxylation and extrusion of carbon disulfide are other fragmentations observed.

Study on the decomposition products of thiadiazinthione and their anticancer properties

Study of the anticancer properties of thirty-four 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazin-2-thione derivatives has been carried out by using cytotoxicity assays against HeLa, HT-29 and Hep G2 cells. The decomposition products of thiadiazinthione 1 m have been studied and their anticancer properties evaluated.

Etiological Characterization of 512 Severely Mentally Retarded Institutionalized Patients in Havana

OBJECTIVE

To investigate etiological factors in severe mental retardation (SMR).

METHODS

An etiological study is presented of 512 SMR patients in five specialized institutions in Havana.

RESULTS

Prenatal, perinatal and postnatal causes were apparent in 58.0, 24.8 and 11.1% of the patients, respectively; infantile psychosis was determined in only 0.4%. The remaining 5.6% were classified as having SMR of undeterminable origin, i.e. patients with apparently normal pre-, peri- and postnatal histories who had neither dysmorphism nor affected first-degree relatives, and had a normal karyotype and metabolic screen. Among prenatal causes, genetic factors were the most frequent (82.8%), while environmental factors were apparent in only 5.3% of these cases. Of the cases with prenatal genetic etiology, chromosomal aberrations were present in 86.5% (Down syndrome 96.2% and 3.7% other chromosomal aberrations), monogenic disorders in 11.3% [neurocutaneous diseases (32.1%) and fragile X syndrome (25%) were the most frequent], and multifactorial disorders in 2.0%. Thirty-five patients (11.7%) presented multiple congenital anomalies of 'prenatal unknown' causes. The latter group may include unidentifiable chromosomal aberrations, uniparental disomy, de novo mutations and multifactorial or teratogenic factors.

CONCLUSION

Accurate determination of the etiology of SMR is important not only for genetic counseling purposes, but also in identifying prenatal events which make infants more vulnerable to perinatal risk factors.

Isolation of a gene from Burkholderia cepacia IS-16 encoding a protein that facilitates phosphatase activity

A genomic library from Burkholderia cepacia IS-16 was constructed in Escherichia coli by partial Sau3AI digestion of the chromosomal DNA, with the plasmid vector Bluescript SK. This library was screened for clones able to grow as green stained colonies on selective medium developed for detecting phosphatase-positive colonies. Three green-stained clones (pFS1, pFS2, and pFS3) carried recombinant plasmids harboring DNA inserts of 5.0, 8.0, and 0.9 kb, respectively. DNA hybridization experiments demonstrated the presence of overlapping DNA fragments in the three clones and that these three clones were all derived from Burkholderia cepacia IS-16 genomic DNA. DNA sequence analysis, together with polyacrylamide gels of proteins encoded by E. coli containing pFS3, suggested that the isolated 0. 9-kb DNA fragment encodes the functional portion of a phosphate transport protein.

Auditory event-related potentials in poor readers

Although poor readers (PR) are considered the major group among reading-disabled children, there are not event-related potentials (ERP) studies reported of PR on the subject. In this study, attentional and memory processes were studied in an auditory oddball task in PR and normal controls. ERP to auditory stimuli were recorded in 19 leads of the 10/20 system, using linked earlobes as references, in 20 normal children (10 female) and 20 PR (10 female) of the same age (10-12 years old). Two pure tones (1000 and 3000 Hz) were used in an oddball paradigm. No significant differences were observed in the amplitudes and latencies of N100 between the groups. However, N200 to frequent stimuli and P200 to both frequent and infrequent stimuli were of higher amplitude in poor readers than in normal children. There were no differences between groups in the latency and amplitude of P300. The results suggest that PR use more attentional resources in the components occurring before P300 to both frequent and infrequent stimuli than the normal children, and this finding is particularly marked for PR girls.

Carotenoid content of chlorophycean microalgae: factors determining lutein accumulation in Muriellopsis sp. (Chlorophyta)

Fifteen strains of chlorophycean microalgae have been investigated with regard to their carotenoid profile. Lutein, beta-carotene and violaxanthin were present in virtually all of the strains, lutein, in general, being the most abundant carotenoid, whereas canthaxanthin and astaxanthin were found in some strains only. Chlorella fusca SAG 211-8b, Chlorococcum citriforme SAG 62.80, Muriellopsis sp., Neospongiococcum gelatinosum SAG B 64.80 and Chlorella zofingiensis CCAP 211/14 exhibited high lutein levels, the latter strain containing in addition substantial amounts of astaxanthin. Muriellopsis sp. was further characterized, since besides a high lutein content (up to 35 mg l(-1) culture), it had the highest growth rate (up to 0.17-0.23 h(-1)) and maximal standing cell density (up to 8 x 10(10) cells l(-1) culture). These levels of lutein are in the range of those reported for astaxanthin in Haematococcus and for beta-carotene in Dunaliella, microalgae of recognized interest for the production of these carotenoids. Lutein content of Muriellopsis sp. increased during the exponential phase of growth, with the highest value being recorded in the early stationary phase. Maximum levels of lutein in Muriellopsis sp. cultures were recorded at 20-40 mM NaNO3, 2-100 mM NaCl, 460 micromol photon m(-2) s(-1), pH 6.5 and 28 degrees C, conditions which were, in general, also optimal for cell growth. Growth-limiting conditions, such as pH values of 6 or 9 and a temperature of 33 degrees C, were found to stimulate carotenogenesis in Muriellopsis sp. This strain represents a potential source of lutein, a commercially interesting carotenoid of application in aquaculture and poultry farming, as well as in the prevention of cancer and diseases related to retinal degeneration.