Molecular cloning and characterization of a multidomain endoglucanase from Paenibacillus sp BP-23: evaluation of its performance in pulp refining

The gene celB encoding an endoglucanase from Paenibacillus sp. BP-23 was cloned and expressed in Escherichia coli. The nucleotide sequence of a 4161 bp DNA fragment containing the celB gene was determined, revealing an open reading frame of 2991 nucleotides that encodes a protein of 106,927 Da. Comparison of the deduced amino acid sequence of endoglucanase B with known beta-glycanase sequences showed that the encoded enzyme is a modular protein and exhibits high homology to enzymes belonging to family 9 cellulases. The celB gene product synthesized in E. coli showed high activity on carboxymethyl cellulose and lichenan while low activity was found on Avicel. Activity was enhanced in the presence of 10 mM Ca2+ and showed its maximum at 53 degrees C and pH 5.5. The effect of the cloned enzyme in modifying the physical properties of pulp and paper from Eucalyptus was tested (CelB treatment). An increase in mechanical strength of paper and a decrease in pulp dewatering properties were found, indicating that CelB treatment can be considered as a biorefining. Treatment with CelB gave rise to an improvement in paper strength similar to that obtained with 1,000 revolutions increase in mechanical refining. Comparison with the performances of recently developed endoglucanase A from the same strain and with a commercial cellulase showed that CelB produced the highest refining effect.

A real-coded genetic algorithm for training recurrent neural networks

The use of Recurrent Neural Networks is not as extensive as Feedforward Neural Networks. Training algorithms for Recurrent Neural Networks, based on the error gradient, are very unstable in their search for a minimum and require much computational time when the number of neurons is high. The problems surrounding the application of these methods have driven us to develop new training tools. In this paper, we present a Real-Coded Genetic Algorithm that uses the appropriate operators for this encoding type to train Recurrent Neural Networks. We describe the algorithm and we also experimentally compare our Genetic Algorithm with the Real-Time Recurrent Learning algorithm to perform the fuzzy grammatical inference.

[Stuttering as the only manifestation of a cerebral infarct]

A 53-year-old right-handed man acutely developed stuttering. On his examination there was blocks and repetitions exclusively on first syllables of words in conversational speech, improving in automatic tasks. There was neither aphasia, nor other neurological deficits. An MR imaging of the brain showed a circumscribed cortical infarct on the left precentral circunvolution. Cerebral angiography was consistent with atherosclerotic narrowing of the intracavernous segment of left internal carotid artery. Artery-to-artery embolism was the suggested mechanism for this stroke and the patient was treated with oral anticoagulants for six months. Stuttering improved progressively and the patient became asymptomatic a month after the stroke. Ictal acquired stuttering symptomatic of ischemic stroke without aphasia or other neurological deficit is exceptional. An small infarct on the left motor area as cause of isolated acquired stuttering adds new information about neural circuits involved in this phenomenon.

Stereological study of the adrenal gland of calves treated with clenbuterol

Stereological methods were used to investigate the morphometric variations in the adrenal cell population of calves dosed orally with clenbuterol at an anabolic dose of 20 microg/kg bodyweight per day for 12 weeks. In the treated group the size of the nuclei increased with respect to the control group, and the increases were significant for the maximum linear parameters in all the regions except the zona fasciculata. The largest increases were observed in the epinephrine-producing cells. The quantitative stereological data showed highly significant increases in the nuclear volume fraction, the nuclear surface density and the numerical density in the zona fasciculata of the treated group.

[Late symptomatic initiation of unilateral cerebellar hypoplasia]

A 65-year-old woman developed a progressive action tremor on her left hand for the last two years. On examination an intentional left hand tremor with dysmetria and tendency to deviate to left on tandem were identified. There was no mental deterioration. CT scan and MR imaging disclosed a marked unilateral, left, cerebellar hypoplasia. MR also showed multiple lacunae. Neurological family disease and exposition to drugs or alcohol were not present. In some cases cerebellar hypoplasia could become symptomatic at advanced age as result of concurrent cerebral disease affecting the compensating structures for congenital defect. In this patient a vascular mechanism is suggested as possible late trigger.

Enzymatic method for branched chain alpha-ketoacid determination: application to rapid analysis of urine and plasma samples from maple syrup urine disease patients

A new method for the determination of branched-chain alpha-ketoacid concentration using lactate dehydrogenase (E C 1.1.1.27) isozyme C4 (LDH C4) from mouse testes is proposed. The assay is performed on urine and plasma without previous treatment. Alpha-ketoglutarate and pyruvate are determined on the same sample using glutamate dehydrogenase (GDH, EC 1.4.1.2) and lactate dehydrogenase isozyme A4 (LDH5) respectively and subtracted from the total alpha-ketoacid concentration obtained with LDH C4. This value corresponds to the branched chain alpha-ketoacid. Results were linear within the concentration range 8 to 170 mumoles/L. Detection limit was 8 mumoles/L. Analytical recovery was higher than 91%. For microplate assays, recoveries were higher than 84% and the detection limit was 20 mumoles/L. Determinations performed with GDH, LDH A4 and LDH C4 allow differentiation of E3 deficiency from other clinical phenotypes of maple syrup urine disease. The method is simple and fast, and adaptation to microplates would allow screening of newborns.

estA, a gene coding for a cell-bound esterase from Paenibacillus sp. BP-23, is a new member of the bacterial subclass of type B carboxylesterases

Screening of a gene library from Paenibacillus sp. BP-23 generated in Escherichia coli led to identification of a clone that directed the production of lipolytic activity. From the sequencing data, we found an open reading frame encoding a protein of 485 amino acids with an estimated molecular mass of 53 kDa and a pI of 5.1. Absence of a signal peptide indicated that it was a cell-bound protein. Sequence analysis showed that the protein contained the signature G-XI-S-X2-G included in most serine-esterases and lipases. The cloned protein showed high homology with enzymes belonging to the bacterial subclass of type B carboxylesterases. The enzyme had a significant preference for esters of short-chain fatty acids and showed the kinetics behaviour of a true esterase. Maximum activity was found at pH 7.5 and 37 degrees C, although the enzyme was active in the pH range 6.0- 9.0 and at temperatures up to 45 degrees C. As expected for a serine-esterase, activity was inhibited by phenylmethylsulphonyl fluoride.

Invisible mycosis fungoides: A diagnostic challenge

We describe a 76-year-old woman who presented persistent generalized pruritus as the only cutaneous manifestation of a cutaneous T-cell lymphoma (mycosis fungoides). No cutaneous lesions were observed throughout the patient's course. Skin biopsies obtained from normal-looking pruritic skin revealed a discrete perivascular lymphocytic infiltrate in the upper dermis and focal intraepidermal clusters of atypical lymphoid cells (Pautrier's microabscesses). PCR analysis of TCR-gamma gene disclosed a monoclonal T-cell rearrangement. Sequencing of the PCR monoclonal product identified the J(8)V(2)C(2) TCR gene rearrangement. This observation illustrates the existence of a peculiar and exceedingly rare form of mycosis fungoides characterized only by persistent pruritus unresponsive to several therapeutic approaches. The diagnostic difficulties of this rare variant are stressed.

Comparison of an oleic acid enriched-diet vs NCEP-I diet on LDL susceptibility to oxidative modifications

OBJECTIVE

The objective of this trial was to compare the effect on the susceptibility of plasma Low Density Lipoprotein (LDL) to oxidative modifications of consumption of two oleic rich diets, prepared with two different plant oils, virgin olive oil (OL)1 and refined high monounsaturated fatty acids (MUFA sunflower oil (SU)), with the susceptibility of plasma LDL to oxidation after an National Cholesterol Education Program step 1 (NCEP-I) phase diet.

DESIGN

A randomized crossover design.

SUBJECTS AND INTERVENTIONS

Twenty-two healthy normolipidemic young males consumed an NCEP-I diet for a 4-week period. Subjects were then assigned to two diets each of 4-weeks duration. Group one was placed on an olive oil enriched diet (40% fat, 22% MUFA) followed by a 4-week period of a MUFA diet enriched in sunflower oil (40% fat, 22% MUFA). In group two, the order of the diets was reversed.

RESULTS

Both MUFA diets induced a decrease in saturated (14:0, 16:0, and 18:0) and an increase in monounsaturated and polyunsaturated n-6 (18:2, 20:3, and 20:5) plasma LDL-phospholipid fatty acids, compared to the NCEP-I diet (P<0.01). No significant differences in lag times were observed between the olive oil and the NCEP-I diet periods. However there was a greater inhibition time (P<0.001) when subjects consumed the MUFA rich sunflower oil diet compared to the NCEP-I diet. These differences were probably related to the relative enrichment of plasma LDL particles in alpha-tocopherol due to the high vitamin E content of the MUFA-rich sunflower oil. Indeed, the alpha-tocopherol content was positively correlated with lag time (r=0.338; P<0.008).

CONCLUSION

Our findings suggest that changes in plasma LDL alpha-tocopherol content with practical solid-food diets can decrease its susceptibility to oxidation.

SPONSORSHIP

This work has been supported by grants from the Investigaciones de la Seguridad Social (FIS 92/0182, to Francisco Pérez Jiménez); and from Koype Co, Andújar, Jaén, Spain. European Journal of Clinical Nutrition (2000) 54, 61-67

[The diet rich in monounsaturated fat modifies in a beneficial way carbohydrate metabolism and arterial pressure]

OBJECTIVE

Two dietary regimens recommended for the reduction of coronary risk, by way of their effects on lipid profile, are the diet low in saturated fat and a diet rich in monounsaturated fats (MUFA). However the effects of these diets on carbohydrate metabolism in healthy subjects are not well known. The objective of this study was to compare the effect of both diets on various parameters of carbohydrate metabolism.

METHODS

41 healthy young males were submitted to 3 consecutive diets, each for a duration of 4 weeks. The first diet was rich in saturated fat (SAT) (38% fat, 20% saturated). The second was rich in carbohydrates following the recommendations of the NCEP-I (National Cholesterol Education Program type I) (28% fat, 47% carbohydrates). The last one was a diet rich in monounsaturated fatty acids (38% fat, 22% MUFA). At the end of each dietary period, blood pressure (BP) and blood levels of glucose, insulin and free fatty acids were determined. 29 subjects were also submitted to an oral glucose tolerance test (OGTT) at the end of each diet.

RESULTS

The SAT diet induced the highest levels of insulin after the OGTT. The consumption of the MUFA diet determined the lowest levels of fasting blood glucose (-0.60 mmol/l [13%], p < 0.0002), insulin (-9 microUl/ml [47%], p < 0.0002) and free fatty acids (-0.11 mmol/l [24%], p = 0.006), compared to the NCEP-I diet. Systolic and diastolic blood pressure were higher in the NCEP-I diet than during the other periods (SBP: +6 mmHg compare with SAT [5%], p = 0.0001; and +5 mmHg compare with MUFA [4%], p = 0.0001; DBP: +20 mmHg compare with MUFA [27%], p = 0.0001) and +6 mmHg compared with SAT [8%], p = 0.0001).

CONCLUSION

Of the diets most commonly used for the treatment and prevention of arteriosclerosis, a diet rich in monounsaturated fats is the most beneficial for the healthy population from the point of view of carbohydrate metabolism and blood pressure.

Mini-ICE regimen as mobilization therapy for chronic myelogenous leukaemia patients at diagnosis

Between April 1996 and May 1998, 20 consecutive patients with Ph chromosome-positive CML in first chronic phase without an HLA-identical sibling received the mini-ICE regimen shortly after diagnosis to mobilize progenitor cells into the peripheral blood (PBPCs). The sex distribution was 12 males and eight females and the median (range) age 48.5 (22-62) years. The time interval between diagnosis and mobilization was a median (range) of 2 (0-5) months. Leukaphereses were initiated during recovery from chemotherapy-induced aplasia. A median number of 3 (1-7) aphereses per patient were performed to collect >/=2.0 x 106 CD34+cells/kg. Cytogenetic analysis was performed on the aphereses products of 18 patients. Complete cytogenetic Ph chromosome negativity was observed in four patients, nine had a partial negativity, three a minimal negativity and two no negative cells. Southern blot for bcr-abl was negative in the remaining two patients but the polymerase chain reaction analysis was positive. Following reinfusion, severe neutropenia was present for a median of 8.5 (3-19) days and severe thrombocytopenia lasted a median of 8 (3-18) days. Ten patients did not develop febrile neutropenia with four of them being treated on an outpatient basis. Treatment-related mortality was not observed. In conclusion, our experience demonstrates the feasibility of mobilizing PBPCs shortly after the diagnosis of CML with a safe regimen. Of note, mini-ICE allowed the collection of apheresis products with at least a major component of Ph-negative cells in almost 75% of the patients.