Surgical outcome of low grade astrocytoma of brain

This study was carried out in the department of Neurosurgery, Dhaka Medical College Hospital, Dhaka, Bangladesh, during the period of January 2003 to December 2006 to elucidate the effectiveness of surgical treatment in the management of low grade astrocytoma of brain. For this purpose, a total number of 50 cases admitted during the study period with low grade astrocytoma of brain supported by clinical features and radiological investigations (CT and MRI scan) were included in this study. The mean age of the patient was a 27.3+/-16.9 year ranging from 1.8 to 65.0 years. Males (64.0%) were more in comparison to females (36.0%) with a male female ratio of 1.8:1. The main presenting complaints were headache (100%), convulsion (84.0%), vomiting (80.0%), visual impairment (20.0%), motor deficit (16.0%) and ataxia (14.0%). All cases had a definite diagnostic investigation at the time of admission. Plain x-ray skull was done in all patients followed by CT scan (70%), MRI scan (60%) and both CT and MRI scan (64.0%). Out of 50 patients 60.0% had gross total removal of tumor and 40.0% sub total tumor resection. Histopathological study was done in all cases after tumor resection. Among the gross total tumor removal cases highest percentage had good recovery (93.4%) in the immediate post operative period. Only one (3.3%) patient developed severe disability and equal percentage had moderate disability. Another 2(4.0%), those underwent subtotal tumor resection died during subsequent follow up period at 8th and 14th postoperative day.

Factors influencing the surgical outcome of spontaneous intracerebral haematoma

The study was done for determination of the potential factors of good outcome in spontaneous intracerebral haematoma (SIH) which could be useful for selecting patients for surgical procedure. Subjects were 45 patients with spontaneous intracerebral haematoma (SIH)-Volume >20ml. They were admitted and surgically treated consecutively in Dhaka Medical College with in the 1st day to 4th day of ictus. Haematoma volume was measured on computed tomography (CT) at admission. Good outcome was measured by Glasgow Outcome Scale (GCS) score. Out of 45 patients with ICH, 18(40%) patients had basal ganglia haematoma, 13(28.88%) patients had lobar haematoma, and 2(4.45%) patients had cerebellar haematoma and 7(15.55%) patients had pure ventricular haematoma and 5(11.12%) patients ventricular extension from other location. Among these last 12 patients, 10(83.33%) patients died comparing only 7(21.21%) patients without ventricular involvement died. Fisher's exact test result shows p value is <0.001(Highly significant) and best outcome obtained in cases of lober haematoma in CT scan of brain, the mean volume was 46 cc. and there was strong association between the volume of haematoma and Glasgow outcome scale, that is, more the volume of blood, less the Glasgow Outcome Scale (GOS) and vice versa. P value was <0.001 (Highly significant). In another study the surgical outcome is best if it is done within 48 hours. Fisher's exact test result shows p value is <0.05. So, Good surgical outcome in spontaneous intracerebral haematoma (SICH) can be predicted on admission by volume of haematoma, location of haematoma, time lapse since ictus to surgery. These predictors may be helpful in selecting patients for surgical treatment.

Secondary hormonal manipulations in the management of advanced prostate cancer

Prostate cancer is a heterogeneous disease and clinical outcomes vary considerably after failure of primary androgen ablation. With the development of new therapeutics the management of patients with androgen independent prostate cancer has changed considerably over the last few years. Multiple secondary hormonal manipulations are available and may lead to prolonged periods of clinical response. These maneuvers include the use of oral antiandrogens, antiandrogen withdrawal, ketoconazole, aminoglutethimide, corticosteroids and use of estrogenic compounds. This article reviews the clinical activity of these agents in management of patients with advanced prostate cancer.

Complete Response to Adriamycin and Ifosfamide in a Patient With Sarcomatoid Renal Cell Carcinoma

Sarcomatoid renal cell carcinoma (SRCC) is a heterogeneous disease with generally unreliable response to various therapies in clinical studies. We illustrate a case report in which a woman with metastatic SRCC had a complete and durable response to adriamycin and ifosfamide chemotherapy. We find this to be incongruous with expectations from some recently published data. It underscores the fact that the biology of SRCC needs to be studied in more detail for further subcataloging of the disease into diverse prognostic categories.

Intermittent androgen deprivation therapy for prostate cancer

Androgen deprivation therapy for prostate cancer is associated with several complications, including loss of libido, hot flashes, night sweats, psychological stress, osteoporosis, anemia, fatigue, loss of muscle mass, glucose intolerance, and changes in lipid profile. The natural history of prostate cancer while on such therapy is the attainment of an incurable androgen-independent state. Early diagnosis by prostate-specific antigen screening, longer life expectancies, and a penchant for immediate therapy pose a problem where clinicians have to balance the potential benefits of early hormonal therapy with the risks of development of these metabolic and psychological complications. Intermittent androgen deprivation offers clinicians a prospect to improve quality of life in patients with prostate cancer by harmonizing the benefits of androgen ablation with a reduction in treatment-related side effects and expenditure. In this review we discuss the challenges and opportunities of this mode of therapy and shed light on some of the underlying molecular mechanisms.

Kinetics of enhanced thermostability of an extracellular glucoamylase from Arachniotus sp

Purified extracelluar glucoamylase from Arachniotus sp. was used for kinetic and thermodynamic characterization. Thermal inactivation followed first order kinetics. The denaturation/activation energies of enzyme were 57 and 89 kJ mol(-1), respectively. Both enthalpy and entropy of activation for inactivation were lower than those for glucoamylases reported in literature. It is suggested that the enzyme is highly thermostable and is suitable for industrial applications.

Final diagnoses following C3 (atypical, probably benign) breast cytology

Fine needle aspiration cytology is part of the triple assessment of breast lesions. The final diagnoses are reported in patients with breast lesions that produce C3 or atypical, probably benign cytology. C3 cytology was obtained from 61 breast lesions between January 1998 and December 1999. Ten (16%) of these lesions were malignant, only three of which were clinically or radiologically suspicious or malignant. Three were diagnosed by core biopsy, but three required excision biopsy after a benign core, and four diagnosed by excision without core. For benign lesions; in five the core was considered diagnostic, three were excised to confirm benignity, 11 monitored and 32 excised without core. Core biopsy should be performed in preference to cytology in the assessment of breast lesions. Where C3 cytology is obtained, core biopsy should be performed, but excision biopsy may still be required. The definition of C3 cytology should be changed to indeterminate.

Molecular Characterization of Begomoviruses Associated with Leafcurl Diseases of Tomato in Bangladesh, Laos, Malaysia, Myanmar, and Vietnam

Production of tomato (Lycopersicon esculentum) in Bangladesh, Malaysia, Myanmar, Vietnam, and Laos has been severely affected by yellow leaf curl disease. Tomato leaf samples were collected from symptomatic tomato plants from farmers' fields in the five countries from 1997 to 1999. DNA was extracted from all samples, four from Vietnam, two each from Malaysia, Laos, and Myanmar, and seven from Bangladesh. Virus DNA was amplified by polymerase chain reaction (PCR) using the begomovirus-specific degenerate primer pair PAL1v 1978/PAR1c 715(1), which amplifies the top part of DNA A. All samples gave the expected 1.4-kb PCR product. The PCR product of one sample per country was cloned and sequenced. Based on the sequences of the 1.4-kb DNA products amplified by the first primer pair, specific primers were designed to complete each of the DNA A sequences. Computer-assisted sequence comparisons were performed with begomovirus sequences available in the laboratory at the Asian Vegetable Research and Development Center, Shanhua, Tainan, and in the GenBank sequence database. The five DNA species resembled DNA A of begomoviruses. For the detection of DNA B two degenerate primer pairs were used, DNABLC1/DNABLV2 and DNABLC2/DNABLV2 (DNABLC1: 5'-GTVAATGGRGTDCACTTCTG-3', DNABLC2: 5'-RGTDCACTT CTGYARGATGC-3', DNABLV2: 5'-GAGTAGTAGTGBAKGTTGCA-3'), which were specifically designed to amplify DNA B of Asian tomato geminiviruses. Only the virus associated with yellow leaf curl of tomato in Bangladesh was found to contain a DNA B component, which was detected with the DNABLC1/DNABLV2 primer pair. The DNA A sequence derived from the virus associated with tomato yellow leaf curl from Myanmar (GenBank Accession No. AF206674) showed highest sequence identity (94%) with tomato yellow leaf curl virus from Thailand (GenBank Accession No. X63015), suggesting that it is a closely related strain of this virus. The other four viruses were distinct begomoviruses, because their sequences shared less than 90% identity with known begomoviruses of tomato or other crops. The sequence derived from the virus associated with tomato yellow leaf curl from Vietnam (GenBank Accession No. AF264063) showed highest sequence identity (82%) with the virus associated with chili leaf curl from Malaysia (GenBank Accession No. AF414287), whereas the virus associated with yellow leaf curl symptoms in tomato in Bangladesh (GenBank Accession No. AF188481) had the highest sequence identity (88%) with a tobacco geminivirus from Yunnan, China (GenBank Accession No. AF240675). The sequence derived from the virus associated with tomato yellow leaf curl from Laos (GenBank Accession No. AF195782) had the highest sequence identity (88%) with the tomato begomovirus from Malaysia (GenBank Accession No. AF327436). This report provides further evidence of the great genetic diversity of tomato-infecting begomoviruses in Asia. Reference: M. R. Rojas et al. Plant Dis. 77:340, 1993.

Pronociceptive effects of nociceptin/orphanin FQ (13-17) at peripheral and spinal level in mice

The heptadecapeptide nociceptin/orphanin FQ (N/OFQ) is reported to be metabolized by aminopeptidase N and endopeptidase 24.15. In the present study, N/OFQ C-terminal fragments elicited nociceptive responses in the peripheral nociceptors and in the spinal cord, whereas N-terminal fragments had no significant nociception. The nociceptive effect of N/OFQ (13-17) was most potent and remained unchanged in N/OFQ peptide receptor (NOPR) gene knockout mice, indicating that N/OFQ (13-17)-induced nociception is mediated through a novel mechanism independent of the activation of NOPR. This finding was further confirmed by in vitro guanosine 5'-O-(3-[35S]thio)triphosphate binding experiments, in which N/OFQ (13-17) showed no significant binding activity in baculovirus/sf21 cells expressing NOPR together with G protein alpha(i)1-, beta1-, and gamma2-subunits, whereas N/OFQ showed stimulation in a concentration-dependent manner. On the other hand, although a typical bell-shaped dose-response relationship was observed with a wide range of N/OFQ doses in both peripheral and central nociception tests, N/OFQ (13-17) did not show bell-shaped dose-response relationship in the central nociception test. This finding indicates that N/OFQ (13-17), in contrast to N/OFQ, lacks the postsynaptic antinociceptive actions modulating substance P signaling in the spinal cord. Together, our results suggest that C-terminal fragments of N/OFQ have potent nociceptive actions, and N/OFQ (13-17) could have the potential to mediate its actions through a novel mechanism independent of the activation of NOPR in the nociceptors and in spinal synapses.

Polyphosphate kinase is essential for biofilm development, quorum sensing, and virulence of Pseudomonas aeruginosa

The human opportunistic pathogen Pseudomonas aeruginosa causes a variety of infections in immunocompromised hosts and in individuals with cystic fibrosis. A knockout mutation in the polyphosphate kinase (ppk) gene, encoding PPK responsible for the synthesis of inorganic polyphosphate from ATP, renders P. aeruginosa cells unable to form a thick and differentiated biofilm. The mutant is aberrant in quorum sensing and responses in that production of the quorum-sensing controlled virulence factors elastase and rhamnolipid are severely reduced. In a burned-mouse pathogenesis model, the virulence of the mutant is greatly reduced with severe defects in the colonization of mouse tissues. The conservation of PPK among many bacterial pathogens and its absence in eukaryotes suggest that PPK might be an attractive target for antimicrobial drugs.

Inorganic polyphosphate is needed for swimming, swarming, and twitching motilities of Pseudomonas aeruginosa

Polyphosphate kinase (PPK), encoded by the ppk gene, is the principal enzyme in many bacteria for the synthesis of inorganic polyphosphate (poly P) from ATP. A knockout mutant in the ppk gene of Pseudomonas aeruginosa PAO1 is impaired in flagellar swimming motility on semisolid agar plates. The mutant is deficient in type IV pili-mediated twitching motility and in a "swarming motility" previously unobserved in P. aeruginosa. In swarming cultures, the polar monotrichous bacteria have differentiated into elongated and polar multitrichous cells that navigate the surface of solid media. All of the motility defects in the ppk mutant could be complemented by a plasmid harboring the ppk gene. Because bacterial motility is often crucial for their survival in a natural environment and for systemic infection inside a host, the dependence for motility on PPK reveals important roles for poly P in diverse processes such as biofilm formation, symbiosis, and virulence.

Inorganic polyphosphate is required for motility of bacterial pathogens

The ppk gene encodes polyphosphate kinase (PPK), the principal enzyme in many bacteria responsible for the synthesis of inorganic polyphosphate (polyP) from ATP. A null mutation in the ppk gene of six bacterial pathogens renders them greatly impaired in motility on semisolid agar plates; this defect can be corrected by the introduction of ppk gene in trans. In view of the fact that the motility of pathogens is essential to invade and establish systemic infections in host cells, this impairment in motility suggests a crucial and essential role of PPK or polyP in bacterial pathogenesis.

Carboxy-group modification: high-temperature activation of charge-neutralized and charge-reversed beta-glucosidases from Aspergillus niger

Purified beta-glucosidase from Aspergillus niger NIAB280 was chemically modified by l-ethyl-3-(3-dimethyl-aminopropyl)-carbodi-imide (EDC) in the presence of glycinamide (GAM) as nucleophile under various conditions to study the role of carboxy groups in the catalytic mechanism of this enzyme. beta-Glucosidase was inactivated by the binding of one mol of EDC per mol of the enzyme with a second-order rate constant of 4.77 x 10(-2) mM min-1. Glucose, as competitive inhibitor, partly protected the active-site carboxy group against chemical modification, with a Kd of 3.64 mM. The pH dependence of chemical modification by EDC showed that first-order rate constants decreased with increasing pH, indicating that the proton donating group is a carboxy group. The pKa values of the acidic and basic limbs of the native enzyme were 2.9 and 6.5 respectively. beta-Glucosidase was modified by EDC in the presence of GAM and ethylenediamine dihydrochloride (EDAM) as nucleophiles for 60 min. The effects of neutralization (GAM) and reversal (EDAM) of the negative charges of surface carboxy groups on the kinetic properties of the enzyme were also studied. Native beta-glucosidase, GAM and EDAM had Vmax/K(m) values of 0.73, 1.22 and 0.60 respectively at 40 degrees C. Interestingly, the activation energy profiles of native beta-glucosidase (103 and 79 kJ/mol) were biphasic, whereas those of GAM (137, 101 and 30 kJ/mol) and EDAM (285, 100 and 29 kJ/mol) were triphasic, indicating significant activation of modified beta-glucosidases at temperatures higher than 50 degrees C. The pKa values of both the active-site carboxy groups as well as the pH optima of GAM and EDAM were also significantly decreased compared with those of the native beta-glucosidase.

Purification and the effect of manganese ions on the activity of carboxymethylcellulases from Aspergillus niger and Cellulomonas biazotea

Carboxymethylcellulases (CMCases) from Aspergillus niger and Cellulomonas biazotea were purified by a combination of ammonium sulfate precipitation, anion-exchange and gel-filtration chromatography with a 12- and 9-fold increase in the purification factor. The native and subunit molar mass of CMCase from A. niger were 40 and 25-57 kDa, respectively, while those from C. biazotea were 23 and 20-30 kDa, respectively. Low concentrations of Mn2+ activated the enzymes from both organisms (mixed activation) with apparent activation constants of 0.80 and 0.45 mmol/L of CMCases from A. niger and C. biazotea, respectively, while at higher CMC concentrations Mn2+ inhibited the enzymes (mixed and partial uncompetitive inhibition). The reason for this complex behavior is that more than one Mn2+ bind to the same enzyme form with the apparent average inhibition constants of 2.7 and 1.3 mmol/L for CMCases from A. niger and C. biazotea, respectively.

Stability and identification of active-site residues of carboxymethylcellulases from Aspergillus niger and Cellulomonas biazotea

Determination of the apparent pKa's of purified carboxymethylcellulases from Aspergillus niger and Cellulomonas biazotea at different temperatures and in the presence of dioxane indicated two side chain carboxyl groups which controlled the limiting rate in both organisms. The thermostability of both enzymes slightly decreased with increasing pH from 5 to 75 but was unaffected in the presence of 0.5 mmol/L Mn2+. The CMCase from C. biazotea had an activation energy of 35 kJ/mol and a half-life of 89 min in the presence of 8 mol/L urea at 40 degrees C. The half-life of CMCase from A. niger in 8 mol/L urea and at 37 degrees C was 125 min as determined by a 0-9 mol/L transverse urea gradient PAGE. The CMCases from A. niger and C. biazotea had the same thermostabilities in the absence of CMC although the enzyme from the former was more thermostable in the presence of the substrate. The CMCase from A. niger was also more efficient in hydrolyzing CMC than the enzyme from C. biazotea.

Purification and characterization of a beta-glucosidase from Aspergillus niger

The high-molar mass form of beta-glucosidase from Aspergillus niger strain NIAB280 was purified to homogeneity with a 46-fold increase in purification by a combination of ammonium sulfate precipitation, hydrophobic interaction, ion-exchange and gel-filtration chromatography. The native and subunit molar mass was 330 and 110 kDa, respectively. The pH and temperature optima were 4.6-5.3 and 70 degrees C, respectively. The K(m) and kcat for 4-nitrophenyl beta-D-glucopyranoside at 40 degrees C and pH 5 were 1.11 mmol/L and 4000/min, respectively. The enzyme was activated by low and inhibited by high concentrations of NaCl. Ammonium sulfate inhibited the enzyme. Thermolysin periodically inhibited and activated the enzyme during the course of reaction and after 150 min of proteinase treatment only 10% activity was lost with concomitant degradation of the enzyme into ten low-molar-mass active bands. When subjected to 0-9 mol/L transverse urea-gradient-PAGE for 105 min at 12 degrees C, the nonpurified beta-glucosidase showed two major bands which denatured at 4 and 8 mol/L urea, respectively, with half-lives of 73 min.

flaD (sinR) mutations affect SigD-dependent functions at multiple points in Bacillus subtilis

A flaD (sinR) null mutation depressed sigD-lacZ expression only two- to fourfold, whereas a flaD1 point mutation depressed it almost completely. Introduction of pHYSigD, a sigmaD-overproducing plasmid, corrected the filamentous phenotype common to both sinR mutants; autolysin synthesis was restored partially and completely in the flaD1 and flaD (sinR) null strains, respectively. Flagellin synthesis and motility were not restored at all in either strain.

Effects of mecA and mecB (clpC) mutations on expression of sigD, which encodes an alternative sigma factor, and autolysin operons and on flagellin synthesis in Bacillus subtilis

The expression of the major vegetative phase-specific autolysin genes (cwlB [lytC] and cwlG [lytD]) was greatly reduced by mecA and mecB null mutations. In contrast to the negative effects on late competence genes (such as comG) and levansucrase gene (sacB) expression, this positive effect of mec genes on autolysin gene expression was not mediated through the ComK protein but apparently through the level of the SigD protein. The pleiotropic effects of the mec mutations, i.e., the reduction of sigD expression and the overexpression of the ComK protein, seem not to be interwoven since the SigD- and ComK-dependent functions are clearly separable in the mec mutants. We also show that the synthesis of the flagellin protein, which is encoded by the SigD-dependent hag gene, was similarly affected by the mec mutations. Complementation analysis with a SigD-overproducing plasmid, pHYSigD, in mec mutants revealed the reversion of almost all of the SigD-dependent phenotypes except motility. This finding suggested that Mec proteins act on motility genes at two levels, one of which is apparently SigD independent. Finally, we discuss the transcriptional regulation of the sigD gene by multiple regulators, i.e., MecA, MecB, SinR (FlaD), and DegS-DegU, and its implications for cells in a global context.

The stability of extracellular beta-glucosidase from Aspergillus niger is significantly enhanced by non-covalently attached polysaccharides

The removal of noncovalently bound polysaccharide coating from the extracellular enzymes of Aspergillus niger, by the technique of compartmental electrophoresis, had a very dramatic effect on the stability of beta-glucosidase. The polysaccharide-beta-glucosidase complex was extremely resistant to proteinases and far more stable against urea and temperature as compared with polysaccharide-free beta-glucosidase. The beta-glucosidase-polysaccharide complex was 18-, 36-, 40- and 82-fold more stable against chymotrypsin, 3 mol/L urea, total thermal denaturation and irreversible thermal denaturation, respectively, as compared with polysaccharide-free beta-glucosidase. The activation energy of polysaccharide-complexed beta-glucosidase (55 kJ/mol) was lower than polysaccharide-free enzyme (61 kJ/mol), indicating a slight activation of the enzyme by the polysaccharide. No significant difference could be detected in the specificity constant (V/K(m)) for A-nitrophenyl beta-D-glucopyranoside between polysaccharide-free and polysaccharide-complexed beta-glucosidase. We suggest that the function of these polysaccharides secreted by fungi including A. niger might be to protect the extracellular enzymes from proteolytic degradation, hence increasing their life span.

Glucosaminidase of Bacillus subtilis: cloning, regulation, primary structure and biochemical characterization

The 90 kDa glucosaminidase protein was purified to apparent homogeneity from vegetative cells of Bacillus subtilis AC327, and then the corresponding gene was cloned into Escherichia coli in two inactive forms by standard procedures. Nucleotide sequencing of the glucosaminidase region revealed a monocistronic operon, (designated lytD = cwIG) encoding a 95.6 kDa protein, comprising 880 amino acid residues, which has a typical signal peptide. Moreover, another monocistronic operon (designated pmi = orfX), encoding a 35.4 kDa protein, was found upstream of the glucosaminidase gene. Expression of a lytD-lacZ fusion gene, driven by lytD regulatory sequences, was observed during the exponential growth phase. The introduction of a sigD null mutation greatly reduced (by about 95%) the expression of the fusion. Amino acid sequence analysis of the glucosaminidase showed two types of direct repeats, each type being present twice, in the N-terminal-to-central region of the glucosaminidase: these repeats probably represent the cell-wall-binding domain. Zymographic analysis revealed that the 90 kDa glucosaminidase is partly processed to several smaller proteins (35-39 kDa), retaining lytic activity. Processing of these proteins occurred between the N-terminal cell-wall-binding and C-terminal catalytic domains of the glucosaminidase, the site being located between the 569th and 606th codons of the glucosaminidase. Serial deletions from the N-terminus of the glucosaminidase revealed that the loss of more than one repeating unit drastically reduces its lytic activity toward cell walls. The lytD gene product, in either an intact or a truncated form, was found to be lethal for E. coli, and the N-terminally truncated glucosaminidase proteins, produced in E. coli, were very unstable. The partially purified glucosaminidase from B. subtilis was found to be very unstable at low ionic strength at 37 degrees C, but this instability was overcome by the addition of either SDS-purified cell wall or protease inhibitor (PMSF) to the enzyme or after purification of the glucosaminidase to apparent homogeneity.

A simple and nondestructive method for the separation of polysaccharides from beta-glucosidase produced extracellularly by Aspergillus niger

An apparatus based on electrophoresis has been devised that removes noncovalently bound polysaccharides from extracellular proteins of Aspergillus niger with concomitant partial beta-glucosidase purification and concentration. The apparatus consists of a series of three chambers separated by polyacrylamide gels. Dialyzed and concentrated crude extract of Aspergillus niger containing beta-glucosidase was poured into the middle chamber, while smaller anodic and cathodic chambers contained buffer. When electric current was applied, negatively charged protein-polysaccharide complexes moved toward the anode. Most of the negatively charged proteins, including beta-glucosidase, crossed the gel barrier into the anodic compartment, while neutral polysaccharides were either trapped in the gels or remained in the middle chamber. In this way, 125 ml of dialyzed and concentrated crude extract of Aspergillus niger was processed. Therefore, after 24 h of electrophoresis, 68% of the proteins and 90% of the beta-glucosidase activity, but only negligible amounts of polysaccharide, were transferred to the anodic chamber. The removal of high-molecular-weight polysaccharide from beta-glucosidase had a detrimental effect on the stability of the enzyme.

Effect of degS-degU mutations on the expression of sigD, encoding an alternative sigma factor, and autolysin operon of Bacillus subtilis

Primer extension analysis of transcripts of the Bacillus subtilis autolysin (cwlB) operon indicated that SigD-dependent transcripts from the Pd promoter are missing in the degU32(Hy) and degS200 (Hy) mutants. The degU32(Hy) mutation caused a 99% reduction in the expression of a sigD-lacZ translational fusion gene constructed in the B. subtilis chromosome. The phosphorylated form of the DegU protein seems to be a regulator for expression of the sigD gene.

Bacillus subtilis mutant deficient in the major autolytic amidase and glucosaminidase is impaired in motility

The purified autolytic endo-beta-N-acetylglucosaminidase of Bacillus subtilis AC327 was cleaved with cyanogen bromide, and the N-terminal amino acid sequence of one of the peptide fragments was determined. Then, a DNA fragment containing a part of the glucosaminidase gene was cloned into Escherichia coli JM109 using synthetic oligonucleotides as probes whose sequences had been deduced from the N-terminal amino acid sequence. Zymographic analysis showed that the resultant glucosaminidase-deficient strain lacked a 35-kDa lytic band in addition to a 90-kDa lytic one corresponding to the glucosaminidase. A double mutant strain deficient in the major two autolysins (amidase and glucosaminidase) exhibited greatly impaired motility on a swarm plate whereas the single mutant strains were motile.

Molecular cloning and sequencing of the upstream region of the major Bacillus subtilis autolysin gene: a modifier protein exhibiting sequence homology to the major autolysin and the spoIID product

The upstream region of the N-acetylmuramoyl-L-alanine amidase gene (cwlB; a major Bacillus subtilis autolysin) was cloned into Escherichia coli by chromosome walking. Sequencing of the region showed the presence of two open reading frames, one (designated as cwbA) which starts at a UUG codon and encodes a polypeptide of 705 amino acids with an M(r) of 76,725, and the other (designated as lppX), upstream of cwbA, comprising 102 amino acids and having a signal sequence characteristic of a lipoprotein. Purification of the CwbA protein and determination of its N-terminal amino acid sequence revealed that it contains a presumed signal peptide which is processed after Ala at position 25 from the N-terminal, and that the M(r) of the mature form is 75,000. The amino acid sequences of the N-terminal and C-terminal regions of CwbA were found to be highly homologous with those of the cell wall binding domain of CwlB and the spoIID gene product, respectively. CwbA stimulated the major autolysin activity approximately threefold in vitro. These data indicate that CwbA is the modifier protein of the major autolysin reported by Herbold, D. R. & Glaser, L. (1975; Journal of Biological Chemistry 250, 1676-1682). In-frame fusion between the lppX and lacZ genes demonstrated that lppX is translated in vivo and expressed during the exponential growth phase.

Reactions between aqueous zinc, aluminium and iron with increasing solutionpH

Solutions of zinc, aluminium and/or iron, as chlorides in NaCl of ionic strength 0.13 mol/l atpH 3, were mixed to give initial concentrations of 0-5, 5-50 and 10-100 μg/ml, respectively. Sodium hydroxide was then added to increase thepH in a range up to 7. Turbidity was measured and equilibrium concentrations were determined after filtration (< 0.1 μm). Decrease inpH on mixing suggested an immediate reaction, with the release of protons. At allpH values Zn concentration decreased with increasing initiai concentrations of Fe and Al. Adsorption and/or nucleation of Zn with Fe and Al was highlypH dependent and increased markediy with increasingpH. The particle size of the products increased with increasingpH and initial concentration of the elements. Increasing Al concentration decreased the size of Fe nucleates at a given Fe concentration. The results suggest that co-precipitation may be involved as well as adsorption. This has important consequences for the availability of Zn to plants, especially in Zn-deficient soils, and is of relevance to the products of mixing acid drainage waters with streams and lakes.

Lead, cadmium and nickel contents of vegetables grown in industrially polluted and non-polluted areas of Bangladesh

The levels of lead (Pb), cadmium (Cd), and nickel (Ni) in spinach (Spinacia oleracea), tomato (Lycopersicon esculentum) and cauliflower (Brassica oleracea) and in the rizosphere soils of the industrially polluted (Konabari, Gazipur; Keranigonj, Dhaka), and non-polluted (Bangladesh Agricultural Research Institute-BARI, Gazipur) areas were studied. Four samples from each area were collected during February 2008. Their concentrations varied with the metals and locations, showing the trend: Ni>Pb>Cd and directly polluted> indirectly polluted>non-polluted soils. The order of the elements in spinach, tomato, and cauliflower and their concentration ranges in μg/g of dry weight were Ni (1.265-5.369), (2.031-4.957), (1.698-4.447); Pd (0.767-1.440), (1.027-1.968), (0.486-1.119); and Cd (0.559-1.40), (0.630-1.303), (0.506-0.782), respectively. Similarly, the order of the elements in rizosphere soils of spinach, tomato, and cauliflower and their concentration ranges in μg/g of dry weight were Ni (12.29-31.52), (13.67-31.98), (14.20-34.34); Pd (3.560-7.980), (3.900-8.447), (3.718-7.337); and Cd (1.473-3.760), (1.553-3.833), (1.640-3.670), respectively. Lead concentration was higher in tomato, followed by spinach and the least in cauliflower irrespective of the location. Cadmium and Ni concentration were found in the order of spinach>tomato>cauliflower, especially in the industrially polluted areas. Concentrations of metals in vegetable samples were related to their concentration in the corresponding soils. Lead, Cd, and Ni concentrations in the studied vegetables were higher than those found in vegetables from other countries, but they were lower than the maximum level allowed in India. Metal transfer factors from soil to vegetables are found to be significant for Cd, Pb and Ni. Key Words: Cadmium; lead; nickel; polluted soils; vegetables. DOI: 10.3329/bjar.v34i4.5831Bangladesh J. Agril. Res. 34(4) : 545-554, December 2009

High Frequency In Vitro Propagation of Adhatoda vasica Nees through Shoot Tip and Nodal Explants Culture

An efficient protocol for in vitro propagation of Adhatoda vasica Nees was established using shoot tip and nodal explants from field grown mature plant. Proliferation of multiple shoots was achieved on MS medium supplemented with different concentrations and combinations of cytokinins (0.5-4.0 mg/l) and auxins (0.1-1.0 mg/l). Maximum number of shoots per explant (13.0) was obtained on MS medium supplemented with 2.0 mg/l BAP + 0.2 mg/l NAA. Among two types of explants used in this study, nodal explants showed better response in respect of multiple shoot production. The elongated shoots were excised and subcultured for rooting on MS medium supplemented with different concentrations of auxins (IBA and NAA). Highest 80% rooting was achieved; and three to four roots per shoot were recorded in medium with 1.0 mg/l IBA within 4 weeks of culture. The in vitro raised plantlets were acclimatized and successfully transferred to natural condition in pot. The regenerated plants were healthy, uniform and identical to the donor plants and the survival percentage was 80%. Key words: Micropropagation, Adhatoda vasica, shoot tip, nodal explant.   DOI:10.3329/jbs.v16i0.3739 J. bio-sci. 16: 35-39, 2008