Tooth width predictions in a sample of Black South Africans

Space analysis during the mixed dentition requires prediction of the mesiodistal widths of the unerupted permanent canines and premolars and prediction tables and equations may be used for this purpose. The Tanaka and Johnston prediction equations, which were derived from a North American White sample, is one example which is widely used. This prediction equation may be inapplicable to other race groups due to racial tooth size variability. Therefore the purpose of this study was to derive prediction equations that would be applicable to Black South African subjects. One hundred and ten pre-treatment study casts of Black South African subjects were analysed from the Department of Orthodontics' records at the University of Limpopo. The sample was equally divided by gender with all subjects having Class I molar relationship and relatively well aligned teeth. The mesiodistal widths of the maxillary and mandibular canines and premolars were measured with a digital vernier calliper and compared with the measurements predicted with the Tanaka and Johnston equations. The relationship between the measured and predicted values were analysed by correlation and regression analyses. The results indicated that the Tanaka and Johnston prediction equations were not fully applicable to the Black South African sample. The equations tended to underpredict the male sample, while slight overprediction was observed in the female sample. Therefore, new equations were formulated and proposed that would be accurate for Black subjects.

Purification and characterization of putative alkaline [Ni-Fe] hydrogenase from unicellular marine green alga, Tetraselmis kochinensis NCIM 1605

Hydrogenase enzyme from the unicellular marine green alga Tetraselmis kochinensis NCIM 1605 was purified 467 fold to homogeneity. The molecular weight was estimated to be approximately 89kDa by SDS-PAGE. This enzyme consists of two subunits with molecular masses of approximately 70 and approximately 19kDa. The hydrogenase was found to contain 10g atoms of Fe and 1g of atom of Ni per mole of protein. The specific activity of hydrogen evolution was 50micromol H(2)/mg/h of enzyme using reduced methyl viologen as an electron donor. This hydrogenase enzyme has pI value approximately 9.6 representing its alkaline nature. The absorption spectrum of the hydrogenase enzyme showed an absorption peak at 425nm indicating that the enzyme had iron-sulfur clusters. The total of 16 cysteine residues were found per mole of enzyme under the denaturing condition and 20 cysteine residues in reduced denatured enzyme indicating that it has two disulfide bridges.

Nitrate reductase-mediated synthesis of silver nanoparticles from AgNO3

Synthesis of silver nanoparticles using alpha-NADPH-dependent nitrate reductase and phytochelatin in vitro has been demonstrated for the first time. The silver ions were reduced in the presence of nitrate reductase, leading to the formation of a stable silver hydrosol 10-25 nm diam. and stabilized by the capping peptide. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-Vis absorption. These studies will help in designing a rational enzymatic strategy for the synthesis of nanomaterials of different chemical composition, shapes and sizes as well as their separation.

The impact of new regulations on the incidence and severity of ocular injury sustained in hurling

AIM

To prospectively evaluate, and compare, the incidence of hurling-related eye injuries in the South East of Ireland before and after implementation of new rules rendering the use of protective head gear and face masks compulsory for players aged 18 years or under.

METHODS

Details relating to patients attending the regional ophthalmic department with injuries sustained during hurling were prospectively recorded between 1 October 2003 and 31 March 2006.

RESULTS

Sixty players attended with hurling-related ocular injuries during the study period. Of these, 43 (71.6%) and 17 (28.3%) sustained the ocular injuries during the 15-month period before, and after implementation of the new rules (1 January 2005), respectively. Restricting our analysis to players aged 18 years or under, and, for statistical validity, to the 12-month period immediately before and immediately after implementation of the new rules, a statistically significant reduction in the number of hurling-related injuries was seen (1 January 2004 to 31 December 2004: 11; 1 January 2005 to 31 December 2005: 2; chi(2) test P<0.05) in this age group. A permanent visual deficit was seen in 11 (18.3%) patients. Of these, one (9%) was aged 18 years or under, and this injury was sustained before the new regulations.

CONCLUSION

New rules rendering the use of protective eye wear compulsory for players aged 18 years or under have resulted in a significant reduction in the incidence and severity of hurling-related eye injuries in this age group.

Outcome of tissue sparing surgical intervention in mine blast limb injuries

OBJECTIVE

To describe the pattern of mine blast limb injuries in civilian population of Kashmir, to evaluate the outcome of tissue sparing surgical intervention in these injuries and to determine the sensitivity of hand-held percutaneous Doppler for tissue viability.

DESIGN

Descriptive study.

PLACE AND DURATION OF STUDY

Combined Military Hospital, Muzaffarabad and Islamic International Medical College Hospitals at Rawalpindi/Islamabad from November 1997 to May 2005.

PATIENTS AND METHODS

One hundred and three patients who sustained mine blast injuries to upper or lower limbs, along side the line of control between the Indian-held Kashmir and Azad Kashmir, regardless of age and gender, were included in this study. Patients who already had amputation after injury at some other place were excluded. All patients were initially managed in emergency and had more than one surgical intervention. Transcutaneous Doppler was used to evaluate the vascularity of the remaining tissue. All patients were operated under spinal or general anaesthesia and had repeated debridements followed by skin cover by split skin graft, full thickness skin graft or rotational flaps. Every patient received at least 5 days course of antibiotics and tetanus prophylaxis. Postoperative rehabilitation and follow-up was conducted for at least 6 months after discharge from the hospital.

RESULTS

Mean age of victims in this study was 22 years. Out of 103 patients, 72 (69.9%) received initial wound care in the peripheral primary health care centre but were not amputated while 31 patients (30%) were just dressed and referred for further treatment at tertiary care hospitals. Eighty-five patients (82.5%), out of the total, had some sort of traumatic amputation at presentation due to the original injury. That included loss of limb below knee in 19 (18.45%) patients, at distal tibiofibular region in 13 (12.6%), mid tarsal amputations in 39(37.9%), and hemi foot amputation in 15 (14.6%) patients. Nine (8.7%) patients had losses of two or less than two toes, 1 (0.97%) patient had injury at mid palmer region, and 5 (4.9%) patients had 2 fingers traumatic amputation. Eighteen (17.5%) patients had soft tissue ( with or without bony injury) injury only without any actual traumatic amputation. Infection rate was 27% in patients who did not have wound care in the periphery. Those who had wound toilet in-the peripheral hospital had infection rate of 16%. Two patients developed fulminating multi-resistant progressive infection requiring below knee amputation.

CONCLUSION

Conservative wound debridement and early skin coverage by different means and preserving maximum soft tissues and bone results in functionally and cosmetically better limb in victims of land mine.

RETRACTED: In vitro and in vivo biological potential and structural aspects of new diorganotin(IV) esters of N-maleoyl-beta-alanine

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Evaluation of emergency revascularisation in vascular trauma

BACKGROUND

Vascular trauma is a common life threatening injury leading to serious consequences if not timely and efficiently managed. We evaluated early surgical interventions aimed at revascularization and thus salvaging limb/organ in life threatening vascular injuries. Aims of our study were to evaluate the outcome of available diagnostic modalities, earliest possible surgical intervention and rate of related complications with particular reference to our existing situation.

METHODS

Emergency diagnostic workup based mainly on clinical evaluations and required laboratory and imaging parameters leading to revascularisation was performed in 48 patients in Combined Military Hospital (CMH) Muzaffarabad and Islamic Medical College Hospitals between June 1997 and December 2001. Data was collected on pre-designed computerized proforma's which were completed by the treating surgeon and data was entered and analyzed accordingly.

RESULTS

Out of the total 48 patients who sustained major vascular injuries during this period, 14 (29.2%) were having injury to upper limb vessels, 26 (54.2%) patients had injury to the lower limb vessels, 6 (12.5%) patients reported with injury to abdominal vessels. One (2%) patient had injury to common carotid artery, while an other patient to thoracic aorta respectively (2%). Penetrating trauma caused 38 (79%) and blunt trauma caused 10 (21%) major vascular injuries. Out of 48 patients, 41 (85.4%) patients were successful managed by vascular reconstruction without any residual disability.

CONCLUSION

Speedy diagnostic work up and early revascularization yields favourable outcome in vast majority of patients requiring vascular repair. Selections of surgical technique including use of autologous vein graft or artificial vascular graft can save many limbs. In order to achieve good results the time lapse between injury and revascularisation should be less than 6 hours.

AIT-082 and methylprednisolone singly, but not in combination, enhance functional and histological improvement after acute spinal cord injury in rats

Extracellular non-adenine based purines are neuroprotective. Preliminary studies indicate that administration of the synthetic purine 4-[[3-(1,6 dihydro-6-oxo-9-purine-9-yl)-1-oxypropyl] amino] benzoic acid (AIT-082, leteprinim potassium) to rats immediately after acute spinal cord injury (SCI), improves functional outcome. The effects of potential new agents are often compared to methylprednisolone (MPSS). We evaluated the effects of AIT-082 and MPSS, separately and in combination, on the functional and morphological outcome of acute SCI in adult rats. After standardized T11-12 spinal cord compression rats were given intraperitoneally one of the following: vehicle (saline); MPSS (30 mg/kg or 60 mg/kg body weight, first dose 15 min after crush); AIT-082 (60 mg/kg body weight daily, first dose 15 min after crush); or AIT-082 plus MPSS. After 1, 3, or 21 days, the rats were perfused for histological analysis. AIT-082 administrations significantly reduced locomotor impairment from 121 days post-operatively. At 1 and 3 days post injury, AIT-082-treatment reduced tissue swelling, tissue loss and astrogliosis at the injured cords but did not alter the extent of hemorrhage and the number of macrophages and/or microglia. MPSS reduced hemorrhage and the number of macrophages and/or microglia, but did not alter astrogliosis. At 21 days, either AIT-082 or MPSS administration improved function and morphology similarly (less tissue loss and astrogliosis). In contrast, administration of AIT-082 and MPSS together abolished the beneficial effects observed when either drug was given individually. These results suggest that MPSS and AIT-082 may exert their beneficial effects through different and potentially antagonistic pathways.

Two orthorhombic crystal structures of a galactose-specific lectin from Artocarpus hirsuta in complex with methyl-alpha-D-galactose

Based on their carbohydrate specificity, the jacalin family of lectins can be divided into two groups: galactose-specific and mannose-specific. The former are cytoplasmic proteins, whereas the latter are localized in the storage vacuoles of cells. It has been proposed that the post-translational modification in some of the lectins that splits their polypeptide chains into two may be crucial for galactose specificity. The mannose-specific members of the family are single-chain proteins that lack the above modification. Although the galactose-specific and the mannose-specific jacalin-type lectins differ in their sequences, they share a common fold: the beta-prism I fold, which is characteristic of Moraceae plant lectins. Here, two crystal structures of a jacalin-related lectin from Artocarpus hirsuta, which is specific for galactose, in complex with methyl-alpha-D-galactose are reported. The lectin crystallized in two orthorhombic forms and one hexagonal form under similar conditions. The crystals had an unusually high solvent content. The structure was solved using the molecular-replacement method using the jacalin structure as a search model. The two orthorhombic forms were refined using data to 2.5 and 3.0 A resolution, respectively. The structures of the A. hirsuta lectin and jacalin are identical. In orthorhombic form I the crystal packing provides three different micro-environments for sugar binding in the same crystal. The observed difference in the specificity for oligosaccharides between the A. hirsuta lectin and jacalin could only be explained based on differences in the molecular associations in the packing and variation of the C-terminal length of the beta-chain. The observed insecticidal activity of A. hirsuta lectin may arise from its similar fold to domain II of the unrelated delta-endotoxin from Bacillus thuringiensis.

The role of hemagglutinins in the midgut extracts of two lines of Aedes aegypti in their susceptibility to Dengue-2 virus

Hemagglutinin activity (HA) was studied in the midgut extracts from highly (h) and lowly susceptible strains of Aedes aegypti mosquitoes to Dengue-2 virus (DEN-2). HA in the midgut extracts from these two isofemale strains of mosquitoes was high in as compared to (h) mosquitoes. HA was found to be higher with chicken red blood cells (RBCs) than with rabbit and human RBCs of O group. Larval midgut extracts showed higher activity than those from adult female mosquitoes. Exposure of midgut extracts to 100 degrees C for 10 mins destroyed the activity. The activity was observed between pH 6 and pH 10. HA in midgut extracts was also studied using twenty different carbohydrates; five of them showed an inhibition of HA. The inhibitory carbohydrates, when incorporated into DEN-2-infected bloodmeal, showed a reduction in the susceptibility of mosquitoes to the virus as compared to the control ones fed on the virus alone. Similarly, when these carbohydrates were incorporated in the DEN-2-infected inoculum, the inoculated mosquitoes showed a reduction in the susceptibility to the virus. HA in the virus-infected midgut extracts was higher than that in the uninfected controls. These results suggest that the presence of HA in the midgut may be one of the factors that affect the susceptibility of Ae. aegypti mosquitoes to DEN-2.

Trends and patterns of tuberculosis: interpretations and prospects of tuberculosis control in Vojvodina, Yugoslavia, 1987-2000

AIM

To assess the trends and pattern of tuberculosis in Vojvodina, Yugoslavia.

METHODS

Using a retrospective design, data on 393 diagnosed TB cases were investigated for the years 1987, 1993 and 2000.

RESULTS

TB case notification has been increasing in Vojvodina. The number of reported TB cases was 146 in 1987, 101 in 1993 and 146 in 2000; cases were predominantly in the age group 20-39 years (44.5%) in 1987, compared to the 40-59 year age group in 1993 and 2000 (38.6% and 45.9%, respectively). The majority of patients belonged to lower socio-economic groups. Manifestations of TB such as cough, weight loss and exhaustion were common. With the increasing trend of alcoholism from 1987 to 2000, delays in reporting were noticed. TB-related mortality was 1.4% in 1987 and 4.1% in 2000. Resistance to TB drugs among previously treated cases was 2.7% in 1987, 0.9% in 1993 and 2.7% in 2000. With respect to the increasing resistance, the levels of detection and surveillance were poor. The implementation of the DOTS strategy remained fairly low.

CONCLUSION

TB is a chronic problem in Vojvodina. Prompt community-oriented actions need to be taken to improve case detection and cure rates through DOTS.

Reducing colonization of Salmonella Enteritidis in chicken by targeting outer membrane proteins

AIMS

To evaluate the ability of Salmonella enterica ser. Enteritidis outer membrane proteins (OMPs) of 75.6 and 82.3 kDa to inhibit or reduce in vivo colonization of S. Enteritidis on intestinal mucosa in chickens.

METHODS AND RESULTS

Nine-week-old specific-pathogen-free chickens were subcutaneously immunized with 75.6 or 82.3 kDa protein, and challenged with a virulent strain of S. Enteritidis. Chickens were killed, and portions of small intestine and caecum were removed at necropsy. The population of S. Enteritidis attached to chicken intestinal mucosa was determined. The population of S. Enteritidis recovered from the small intestine and caecum of chickens immunized with 75.6 or 82.3 kDa protein was significantly (P < 0.05) lower than that recovered from the control birds.

CONCLUSIONS

Salmonella Enteritidis OMPs 75.6 kDa and 82.3 kDa were effective in reducing colonization of S. Enteritidis on intestinal mucosa in chickens.

SIGNIFICANCE AND IMPACT OF THE STUDY

Salmonella Enteritidis OMPs 75.6 or 82.3 kDa could be used as potential vaccines to reduce S. Enteritidis colonization in chickens.

Structural changes enhance the activity of Chainia xylanase in low urea concentrations

Low concentrations of urea (1.2 M) stimulated the activity of endo-xylanase from Chainia by 30%. Subtle structural changes in the monomeric protein were reflected in the secondary and tertiary structure of the enzyme as monitored by fluorescence and circular dichroism. Changes in lambda(max) of emission, the fluorescence intensity and the Stern-Volmer quenching constants for acrylamide, measured in the presence of urea, indicated changes in the microenvironment of the Trp residues, suggesting alterations in tertiary structure. The ellipticity changes at 220 nm and Selcon analysis reflected changes in the content of beta-sheet while both the near- and far-UV CD spectra indicated alterations in the secondary and tertiary structure of the protein in presence of urea. The dissociation constant values (K(d)) show very little change in the affinity of the enzyme for the substrate while the k(cat) values suggest enhanced turnover of the substrate in presence of urea. We suggest that low urea concentrations perturb the conformational state of xylanase leading to an open and a more flexible structure, resulting in enhanced catalytic rates.

Identification of Salmonella enteritidis outer membrane proteins expressed during attachment to human intestinal epithelial cells

AIMS

To express and identify the Salmonella enterica ser. Enteritidis outer membrane proteins that are involved in the attachment to human intestinal epithelial cells.

METHODS AND RESULTS

Salmonella Enteritidis attachment proteins were expressed by infection of human intestinal epithelial cells (int-407) with Salm. Enteritidis strain SE28, followed by pulse labelling with [35S]-methionine. Outer membrane proteins were separated by TritonX-114 phase partitioning, and were detected by Salm. Enteritidis-specific polyclonal antibody. Outer membrane proteins of molecular weights 82.3, 75.6, 49.3, 35.5 and 19.3 kDa were newly synthesized. Expression of 31.2 and 16 kDa proteins was up-regulated, whereas the expression of 40.7 kDa protein was down-regulated. Polyclonal antibodies against the 82.3 and 75.6 kDa proteins significantly (P < 0.05) reduced the binding of Salm. Enteritidis to int-407 cells in vitro.

CONCLUSIONS

Outer membrane proteins 82.3 and 75.6 kDa are potentially involved in the attachment of Salm. Enteritidis to the intestinal mucosa.

SIGNIFICANCE AND IMPACT OF THE STUDY

Outer membrane proteins 82.3 and 75.6 kDa identified in this study could be used as potential vaccines to block or reduce Salm. Enteritidis colonization in chickens.

Diagnosis by polymerase chain reaction of Erysipelas septicemia in a flock of ring-necked pheasants

A flock of 810 pheasants experienced 6.2% mortality over 6 days. Affected birds were weak and lethargic for up to 24 hr before death. Examined birds were thin, and gross lesions consisted of thick opaque crops and cecal cores. Histologically, there was capillariasis of the crop and multifocal ulcerative typhlitis with Heterakis spp. infection, and numerous systemic intravascular monocytes were filled with clusters of blue rod-shaped organisms. The organisms were gram-positive bacilli by Brown and Brenn staining and ultrastructural analysis. Liver bacterial cultures were negative for pathogenic bacteria. Erysipelas septicemia was diagnosed by an Erysipelothrix species-specific polymerase chain reaction method with the substrate DNA isolated from formalin-fixed, paraffin-embedded liver.

Updating of hereditary haemoglobin disorders

Hereditary haemoglobin disorders (E-beta Thalassaemia & Thalassaemia) are inherited as recessive disorders so that the heterozygote subjects are generally healthy. They commonly present with progressive pallor, thalassaemic facies, splenohepatomegaly & growth retardation. Diagnosis of carriers & patients are usually confirmed by haemoglobin electrophoresis. Transfusion-chelation therapy is usually employed for their treatment. Allogenic bone marrow transplantation is the only definite cure. Gene therapy remains to be the major challenging goal of future curative therapy. During the last 10 years wit medical advances, the number of pregnancies in thalassaemia is increasing. Normal pregnancy can be maintained with regular packed blood cells transfusion given carefully. In Bangladesh, HHD can be prevented by I. carrier identification and marriage counseling, II. passing and enforcing laws against marriage between two carriers, III. introducing thalassaemia in school curriculum and IV. creating public awareness.

Inactivation of Escherichia coli O157: H7 and Listeria monocytogenes by PR-26, a synthetic antibacterial peptide

This study reports the antibacterial effect of PR-26, a synthetic peptide derived from the first 26 amino acid sequence of PR-39, an antimicrobial peptide isolated from porcine neutrophils. A three-strain mixture of Escherichia coli O157:H7 or Listeria monocytogenes of approximately 10(8) CFU was inoculated to a final concentration of 10(7) CFU/ml in 1% peptone water (pH 7.0), containing 50 or 75 microg/ml of PR-26, and incubated at 37 degrees C for 0, 6, 12, and 24 h; at 24 degrees C for 0, 12, 24, and 36 h; or at 10 or 4 degrees C for 0, 24, 72, and 120 h. Control samples included 1% peptone water inoculated with each pathogen mixture but containing no PR-26. The surviving population of each pathogen at each sampling time was determined by plating on tryptic soy agar with incubation at 37 degrees C for 24 h. At 37 degrees C, PR-26 decreased E. coli O157:H7 and L. monocytogenes populations by >5.0 log CFU/ml at 12 h, with complete inactivation at 24 h. At 24 degrees C, PR-26 reduced E. coli O157:H7 and L. monocytogenes by approximately 3.5, 4.0, and 4.5 log CFU/ml at the end of 12-, 24-, and 36-h incubations, respectively. At 4 and 10 degrees C, the inhibitory effect of PR-26 on E. coli O157:H7 and L. monocytogenes was significantly lower (P < 0.05) than that at 37 and 24 degrees C: a 2- to 3-log CFU/ml reduction was observed at 120-h incubation. Results indicate that PR-26 could potentially be used as an antimicrobial agent, but applications in appropriate foods need to be validated.

Inorganic-organic hybrids derived from oxovanadium sulfate motifs: synthesis and characterization of [VIVO(mu 3-SO4)(2,2'-bpy)]infinity

The hydrothermal reaction of V2O5, V2O3, 2,2'-bpy and Na2SO4 in dilute sulfuric acid yields a novel hybrid, [VIVO(mu 3-SO4)(2,2'-bpy)]infinity, which demonstrates the potential of constructing a new class of robust composite solids composed of a (V/O/SO4)-based framework decorated with organic functionalities by combining appropriate vanadyl sulfate motifs with a variety of organic ligands.

On the stringent requirement of mannosyl substitution in mannooligosaccharides for the recognition by garlic (Allium sativum) lectin. A Surface Plasmon Resonance Study

The kinetics of the binding of mannooligosaccharides to the heterodimeric lectin from garlic bulbs was studied using surface plasmon resonance. The interaction of the bound lectin immobilized on the sensor chip with a selected group of high mannose oligosaccharides was monitored in real time with the change in response units. This investigation corroborates our earlier study about the special preference of garlic lectin for terminal alpha-1,2-linked mannose residues. An increase in binding propensity can be directly correlated to the addition of alpha-1,2-linked mannose to the mannooligosaccharide at its nonreducing end. Mannononase glycopeptide (Man9GlcNAc2Asn), the highest oligomer studied, exhibited the greatest binding affinity (Ka = 1.2 x 10(6) m(-1) at 25 degrees C). An analysis of these data reveals that the alpha-1,2-linked terminal mannose on the alpha-1,6 arm is the critical determinant in the recognition of mannooligosaccharides by the lectin. The association (k1) and dissociation rate constants (k(-1)) for the binding of Man9GlcNAc2Asn to Allium sativum agglutinin I are 6.1 x 10(4) m(-1) s(-1) and 4.9 x 10(-2) s(-1), respectively, at 25 degrees C. Whereas k1 increases progressively from Man3 to Man7 derivatives, and more dramatically so for Man8 and Man9 derivatives, k(-1) decreases relatively much less gradually from Man3 to Man9 structures. An unprecedented increase in the association rate constant for interaction with Allium sativum agglutinin I with the structure of the oligosaccharide ligand constitutes a significant finding in protein-sugar recognition.

Ribonuclease Rs from Rhizopus stolonifer: lowering of optimum temperature in the presence of urea

RNase Rs showed an approx. 2-fold increase in its activity when incubated in the presence of 2 M urea at 37 degrees C. The increase in its activity, in the presence of urea, was comparable to the activity at its optimum temperature, i.e. 45 degrees C. Compared to the native enzyme at 37 degrees C, the K(m) and V(max) of RNase Rs at 45 degrees C and in the presence of 2 M urea at 37 degrees C showed an increase while k(cat)/K(m) decreased. Arrhenius plots in the presence and absence of urea showed a decrease in the activation energy in the presence of urea. Though there was no change in the secondary structure of the protein in the presence of urea, minor changes were observed in the tertiary structure. Hence, the increase in the activity of RNase Rs, in the presence of 2 M urea at 37 degrees C, is due to the lowering of the activation energy as a result of changes in the microenvironment of the active site.

Molecular characterization of an infectious bronchitis virus strain isolated from an outbreak in vaccinated layers

An infectious bronchitis virus (IBV) strain CT/7852/97 was isolated from a commercial layer flock experiencing decreased egg production and poor egg quality. Reciprocal virus neutralization test demonstrated that the isolate was closely related to Massachusetts, Arkansas, and JMK. With the use of both reverse transcription-polymerase chain reaction-restriction fragment length polymorphism and multiplex polymerase chain reaction methods, results consistently showed that CT/7852/97 isolate was Massachusetts serotype specific only. The nucleotide sequence of S1 polypeptide coding region of CT/7852/97 was determined and compared with the published sequences of 12 IBV strains from North America. The highest nucleotide homology with H120 (97%) and the least homology (62%) with Delaware (De/072/92) were observed. Massachusetts 41 and Beaudette shared 94% and 93%, respectively, nucleotide similarity with CT/7852/97, and Connecticut, JMK, and Arkansas 99 had 94%, 83%, and 78%, respectively, nucleotide similarity with CT/7852/97. Furthermore, no possible recombination site on S1 gene among Massachusetts 41, Arkansas 99, and JMK was detected in the isolate.

A mannose-binding protein from the cell surface of flocculent Saccharomyces cerevisiae (NCIM 3528): its role in flocculation

A cell surface lectin was isolated and purified to homogeneity from the cell walls of a highly flocculent strain of Saccharomyces cerevisiae (NCIM 3528) by chromatography on DEAE-cellulose, phenyl Sepharose and Sephacryl S-300. It showed a molecular mass of 40 kDa on SDS-PAGE. It is an acidic protein with a pI of 4.0 and contains 44% hydrophobic amino acids. The N-terminal sequence up to 10 amino acid residues showed at least 70% homology with the predicted N-terminal sequence of the putative FLO1 as well as FLO5 gene products. The mannose-binding nature of the lectin was indicated by its high affinity and specificity towards the branched trisaccharide of mannose, a ligand which also inhibits the flocculation of yeast cells. Immunofluorescence studies confirmed the presence of lectin on the yeast cell surface and lectin-specific IgGs prevented flocculation of the cells. This cell surface mannose-specific lectin probably plays an important role in flocculation, with the branched trimannoside on the cell wall being the apparent carbohydrate receptor. The N-terminal sequence data gives a primary indication that the lectin could be a product of one of the FLO genes.

Characterization of a thermostable extracellular beta-galactosidase from a thermophilic fungus Rhizomucor sp

An extracellular beta-galactosidase from a thermophilic fungus Rhizomucor sp. has been purified to homogeneity by successive DEAE cellulose chromatography followed by gel filtration on Sephacryl S-300. The native molecular mass of the enzyme is 250,000 and it is composed of two identical subunits with molecular mass of 120,000. It is an acidic protein with a pI of 4.2. Purified beta-galactosidase is a glycoprotein and contains 8% neutral sugar. The optimum pH and temperature for enzyme activity are 4.5 and 60 degrees C, respectively. The enzyme is stable at 60 degrees C for 4 h, and has a t(1/2) of 150 min(-1) at 70 degrees C which is one of the highest reported for fungal beta-galactosidases. Substrate specificity studies indicated that the enzyme is specific for beta-linked galactose residues with a preference for p-nitrophenyl-beta-D-galactopyranoside (pNPG). The Km and Vmax values for the synthetic substrates pNPG and o-nitrophenyl-beta-D-galactopyranoside (oNPG) were 0.66 mM and 1.32 mM; and 22.4 mmol min(-1) mg(-1) and 4.45 mmol min(-1) mg(-1), respectively, while that for the natural substrate, lactose, was 50.0 mM and 12 mmol min(-1) mg(-1). The end product galactose and the substrate analogue isopropyl thiogalactopyranoside (ITPG) inhibited the enzyme with Ki of 2.6 mM and 12.0 mM, respectively. The energy of activation for the enzyme using pNPG and oNPG were 27.04 kCal and 9.04 kCal, respectively. The active site characterization studies using group-specific reagents revealed that a tryptophan and lysine residue play an important role in the catalytic activity of the enzyme.

Production, purification and characterization of a constitutive intracellular alpha-galactosidase from the thermophilic fungus Humicola sp

The thermophilic fungus Humicola sp constitutively produces intracellular alpha-galactosidase (1.33 U mg-1 protein) within 48 h at 45 degrees C in shaken flasks, when grown in a medium containing 7% wheat bran extract as a carbon source and 0.5% yeast extract as a nitrogen source. The enzyme has been purified to homogeneity by ultrafiltration, ethanol precipitation, DEAE cellulose and Sephacryl S-300 chromatography with a 124-fold increase in specific activity and 29.5% recovery. The molecular weight of the enzyme is 371.5 kDa by gel filtration on Sephacryl S-300 and 87.1 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme has an optimum temperature of 65 degrees C and an optimum pH of 5.0. Humicola alpha-galactosidase is a glycoprotein with 8.3% carbohydrate content and is acidic in nature with a pI of 4.0. The KmS for p-nitrophenyl-alpha-D-galactopyranoside, O-nitrophenyl-alpha-D-galactopyranoside, raffinose and stachyose are 0.279, 0.40, 1.45 and 1.42 mM respectively. The enzyme activity was strongly inhibited by Ag+ and Hg2+. D-Galactose inhibited alpha-galactosidase competitively and the inhibition constant (Ki) for galactose was 11 mM.