Identification of the rhizobial symbiont of Astragalus glombiformis in Eastern Morocco as Mesorhizobium camelthorni

Astragalus gombiformis is a desert symbiotic nitrogen-fixing legume of great nutritional value as fodder for camels and goats. However, there are no data published on the rhizobial bacteria that nodulate this wild legume in northern Africa. Thirty-four rhizobial bacteria were isolated from root nodules of A. gombifomis grown in sandy soils of the South-Eastern of Morocco. Twenty-five isolates were able to renodulate their original host and possessed a nodC gene copy. The phenotypic and genotypic characterizations carried out illustrated the diversity of the isolates. Phenotypic analysis showed that isolates used a great number of carbohydrates as sole carbon source. However, although they were isolated from arid sandy soils, the isolates do not tolerate drought stress applied in vitro. The phenotypic diversity corresponded mainly to the diversity in the use of some carbohydrates. The genetic analysis as assessed by repetitive extragenic palindromic (REP)-polymerase chain reaction (PCR) showed that the isolates clustered into 3 groups at a similarity coefficient of 81 %. The nearly-complete 16S rRNA gene sequence from a representative strain of each PCR-group showed they were closely related to members of the genus Mesorhizobium of the family Phyllobactericeae within the Alphaproteobacteria. Sequencing of the housekeeping genes atpD, glnII and recA, and their concatenated phylogenetic analysis, showed they are closely related to Mesorhizobium camelthorni. Sequencing of the symbiotic nodC gene from each strain revealed they had 83.53 % identity with the nodC sequence of the type strain M. camelthorni CCNWXJ 40-4^T.     

Primary malignant non-Hodgkin's lymphoma of the breast: a study of seven cases and literature review

ABSTRACT: INTRODUCTION: Primary breast lymphoma is an uncommon disease with poor clinical outcome. Breast lymphomas present less than 0.5% of malignant breast neoplasms and 2.2% of extranodal lymphomas. This study investigated the clinicopathological features and optimal treatment of PBL. Case presentations Clinical records of seven Moroccan PBL patients, treated at the National Institute of Oncology, Rabat, Morocco, from 2002 to 2010, were reviewed. Six of the patients were women and one a man, with ages ranging from 32 to 76. Five patients had stage IE and two stage IIE. All of the patients were classified with DLBCL. Of seven patients, one received a mastectomy and three excision of the breast lesion. Axillary dissection was performed in three patients. Two patients received chemotherapy followed by radiotherapy, while four received chemotherapy alone. Complete remission (CR) following primary treatment for all patients with PBL except in two cases was obtained. In one patient, recurrence occurred. CONCLUSIONS: There is no consensus on the question of how to best treat PBL: Mastectomy offers no benefit in the treatment of PBL. The combined therapy approach, with chemotherapy and radiotherapy, is the most successful treatment. PBL is poorly represented in rituximab-containing trials in DLBCL patients; there is not much experience with this agent in breast DLBCL. Because of the high incidence of central nervous system (CNS) involvement in PBL patients, many authors strongly believe that patients with aggressive forms of PBL should receive CNS infiltration prophylaxis.     

Comparative evaluation of the toxicity induced by mussels (Mytilus galloprovincialis) from two sites of the Moroccan Atlantic coast in mice

Atlantic coast in mice. Preliminary studies showed that seawater contains heavy metals from domestic, agricultural and industrial wastes. Marine bivalves concentrate these pollutants by filtration and serve as vectors in human exposure. The objective of this study was to determine the concentration of heavy metals; cadmium (Cd); chromium (Cr), and lead (Pb) in mussels (Mytilus galloprovincialis) collected in two coastal sites; Jorf Lasfar (JL) (neighbouring a phosphate processing platform) and Oualidia (OL) (a vegetable growing area) located at 120 and 190 km south of Casablanca, respectively. Another objective was to test and compare the toxicity of these mussels on mice. The results indicated the presence of heavy metals (Cd, Cr, and Pb) in mussels at different concentrations, depending on the collection period. Higher concentrations were obtained at JL than at OL: for example, Cd concentrations were 80 +/- 15 to 199 +/- 28 versus 23 +/- 5 microg/g mussel dry weight, respectively. Cramming with mussel powder did not increase Cd, Cr, or Pb concentration in either liver or kidneys of treated mice. The relative kidney weights were reduced. Increased glucose urea was observed in animals' urine. Treatment with mussels from OL induced significant reduction (20%) in mice body weight, together with an increase in creatinuria. These results indicate that mussels collected from OL are more harmful than those obtained from JL are. All these mussels should not be recommended for human consumption.     

Taurine increases mitochondrial buffering of calcium: role in neuroprotection

Summary. We have determined the role of mitochondria in the sequestration of calcium after stimulation of cerebellar granule cells with glutamate. In addition we have evaluated the neuroprotective role of taurine in excitotoxic cell death. Mitochondrial inhibitors were used to determine the calcium buffering capacity of mitochondria, as well as how taurine regulates the ability of mitochondria to buffer intracellular calcium during glutamate depolarization and excitotoxicity. We report here that pre-treatment of cerebellar granule cells with taurine (1 mM, 24 h) significantly counteracted glutamate excitotoxicity. The neuroprotective role of taurine was mediated through regulation of cytoplasmic free calcium ([Ca²⁺] _i ), and intra-mitochondrial calcium homeostasis, as determined by fluo-3 and ⁴⁵Ca²⁺-uptake. Furthermore, the overall mitochondrial function was increased in the presence of taurine, as assessed by rhodamine accumulation into mitochondria and total cellular ATP levels. We specifically tested the hypothesis that taurine reduces glutamate excitotoxicity through both the enhancement of mitochondrial function and the regulation of intracellular (cytoplasmic and intra-mitochondrial) calcium homeostasis. The role of taurine in modulating mitochondrial calcium homeostasis could be of particular importance under pathological conditions that are characterized by excessive calcium overloads. Taurine may serve as an endogenous neuroprotective molecule against brain insults. Authors’ address: Abdeslem El Idrissi, Biology Department and Center for Developmental Neuroscience, College of Staten Island/CUNY, 6S-134 Staten Island, NY 10314, U.S.A.     

A new concept of olfactory biosensor based on interdigitated microelectrodes and immobilized yeasts expressing the human receptor OR17-40

This work shows the feasibility of an olfactory biosensor based on the immobilization of Saccharomyces cerevisiae yeast cells genetically modified to express the human olfactory receptor OR17-40 onto interdigitated microconductometric electrodes. This olfactory biosensor has been applied to the detection of its specific odorant (helional) with a high sensitivity (threshold 10⁻¹⁴ M). In contrast, no significant response was observed using a non-specific odorant (heptanal), which suggests a good selectivity. Thus, this work may represent a first step towards a new kind of bioelectronic noses based on whole yeast cells and allowing a real time monitoring of olfactory receptor activation. Presented at the joint biannual meeting of the SFB-GEIMM-GRIP, Anglet, France, 14–19 October, 2006.     

Poly(alpha-alkyl gamma-glutamate)s of microbial origin. 2. On the microstructure and crystal structure of poly(alpha-ethyl gamma-glutamate)s

The stereochemical microstructure and crystalline structure of nearly racemic poly(alpha-ethyl gamma,DL-glutamate) obtained by esterification of biosynthetic poly(gamma-glutamic acid) were examined by NMR, DSC, and powder X-ray diffraction. The two enantiomerically pure poly(alpha-ethyl gamma-glutamate)s, as well as the racemic stereocopolymers with random and alternating microstructure, were prepared by chemical synthesis and studied in parallel to help in the interpretation of the data. The (13)C NMR analysis revealed that biosynthetic poly(alpha-ethyl gamma,DL-glutamate) consists of a block stereocopolymer accompanied by minor amounts of a mixture of the two optically pure homopolymers. The polymer is crystalline, with a degree of crystallinity and crystal structure essentially similar to those displayed by the optically pure polymers but clearly different from the alternating copolymer. Conversely, the racemic stereocopolymer with a random microstructure prepared by chemical synthesis is amorphous. The crystal structure of the racemic mixture of the D- and L-homopolymers seems to be very close to that of the biosynthetic stereocopolymer, although some indications suggesting the existence of a stereocomplex were found.     

Spiroquinazolinones as novel, potent, and selective PDE7 inhibitors. Part 1

The synthesis and SAR studies of spiroquinazolinones as novel PDE7 inhibitors are discussed. The best compounds from the series displayed nanomolar inhibitory affinity and were selective versus other PDE isoenzymes.     

Biodiversity of lactic acid bacteria in Moroccan soft white cheese (Jben)

The bacterial diversity occurring in traditional Moroccan soft white cheese, produced in eight different regions in Morocco, was studied. A total of 164 lactic acid bacteria were isolated, purified and identified by whole-cell protein fingerprinting and rep-PCR genomic fingerprinting. The majority of the strains belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Enterococcus. Sixteen species were identified: Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, Lactobacillus brevis, Lactobacillus buchneri, Lactococcus lactis, Lactococcus garvieae, Lactococcus raffinolactis, Leuconostoc pseudomesenteroides, Leuconostoc mesenteroides, Leuconostoc citreum, Eterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus saccharominimus and Streptococcus sp.     

Neuro-endocrine basis for altered plasma glucose homeostasis in the Fragile X mouse

Background

The fragile X mouse model shows an increase in seizure susceptibility, indicating an involvement of the GABAergic system via an alteration in cellular excitability. In the brain, we have previously described a reduction in GABA_A receptor expression as a likely basis for this susceptibility. In the brains of fragile X mice, this reduction in receptor expression culminates with a concomitant increase in the expression of glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis. Further, voltage-sensitive calcium channel expression is reduced in the pancreas of the fragile X mouse. Since there are considerable similarities in the GABAergic system in the brain and pancreas, we evaluated the protective role of taurine in pancreatic islet development in both wild type (WT) and fragile X mice (KO).

Methods

One-month-old FVB/NJ males or age-matched fmr1-knockout (KO) mice were supplemented with taurine in drinking water (0.05% w/v) for four weeks. Age-matched controls were fed water only for the same duration. At four weeks, mice were sacrificed and pancreases processed for histology and immunohistochemical studies on changes of insulin, glucagon and somatostatin expression. Additional mice were subjected to a glucose tolerance test.

Results

Taurine treatment resulted in a significant increase in the number and size of islets. WT taurine-fed mice, slightly hypoglycemic prior to glucose injection, showed significantly reduced plasma glucose at 30 min post-injection when compared to control mice. KO mice had normal baseline plasma glucose concentration; however, following glucose injection they had higher plasma glucose levels at 30 min when compared to controls. Supplementation of taurine to KO mice resulted in reduced baseline levels of plasma glucose. After glucose injection, the taurine-fed KO mice had reduced plasma glucose at 30 min compared to KO. Concomitant with the increased islets size and glucose tolerance observed in taurine-fed mice there was an increase in insulin, glucagon and somatostatin immunoreactivity in the islets of WT mice. In the KO mice however, insulin levels were not affected whereas glucagon and somatostatin levels were reduced. Exocytosis of these hormones is calcium-dependent, therefore any exacerbation of calcium homeostasis could affect hormone release. We found the expression of the voltage sensitive calcium channels (VSCC) is drastically reduced in the pancreas of fragile X mice.

Conclusions

During early development, the VSCC play an important role in calcium-dependent gene expression. Since these channels are also involved in depolarization and calcium-mediated vesicular release of neurotransmitters and pancreatic hormones, alterations in the expression of VSCC not only will affect calcium-mediated gene expression but also hormonal and neurotransmitter release creating therefore a neuroendocrine perturbation in the fragile X that may potentially affect other organ systems. We find that in the fragile X mouse, taurine treatment may partially restore functionality of the neuro-endocrine pancreas.

     

Diversity of bacteria that nodulate Prosopis juliflora in the eastern area of Morocco

A total of 274 bacterial strains were isolated from the root nodules of Prosopis juliflora, growing in two arid soils of the eastern area of Morocco. A physiological plate screening allowed the selection of 15 strains that could tolerate NaCl concentrations between 175 and 500 mM. These were compared with 15 strains chosen from among the ones which did not tolerate high salinity. The diversity of strains was first assessed by rep-PCR amplification fingerprinting using BOXA1R and ERIC primers. An analysis of the PCR-amplified 16S rDNA gene digestion profiles using five endonucleases indicated the presence of different lineages among the taxa associated with P. juliflora nodules in the soils studied. Nucleotide sequencing of the small subunit rRNA gene and BLAST analysis showed that P. juliflora could host at least six bacterial species in this region and that the identity of those associated with high salt tolerance was clearly distinct from that of the salt-sensitive ones. Among the former, the first type displayed 99% similarity with different members of the genus Sinorhizobium, the second 97% similarity with species within the genus Rhizobium, while the third ribosomal type had 100% homology to Achromobacter xylosoxidans. Within the salt-sensitive isolates the prevailing type observed showed 98% similarity with Rhizobium multihospitium and R. tropici, a second type had 98% similarity to R. giardinii, and a further case displayed 97% colinearity with the Ensifer group including E. maghrebium and E. xericitae. All of the thirty strains encompassing these types re-nodulated P. juliflora in microbiologically controlled conditions and all of them were shown to possess a copy of the nodC gene. This is the first report detecting the betaproteobacterial genus Achromobacter as nodule-forming species for legumes. The observed variability in symbiont species and the abundance of nodulation-proficient strains is in line with the observation that the plant always appears to be nodulated and efficiently fixing nitrogen in spite of a wide range of soil and environmental conditions.