Repeat breeding: prevalence and potential causes in dairy cows at different milk pocket areas of Bangladesh

The objective of this study was to figure out the prevalence and probable causes of repeat breeding (RB) in dairy cows. Hence, a cross-sectional study was conducted on randomly selected 265 dairy farms in Sirajganj, Bogura, Rangpur, Satkhira, and Munshiganj districts of Bangladesh from December 2018 to February 2019. Data were collected through a direct interview method using a survey questionnaire. The reproductive organs of repeat breeder cows were examined for pathological, infectious, and functional reasons, and genital tract abnormalities. Additionally, the influence of nutrition, season, and age on the frequency of RB was recorded. The prevalence of RB was 28% among the 3824 cows investigated. Among the total repeat breeder cases, 72.54% of RB cases were found in Holstein-Friesian crossbred, 23.90% in Jersey crossbred, 1.50% in Sahiwal crossbred, and 2.06% in indigenous cows. The prevalence of RB was significantly highest (P < 0.01) in Satkhira (44.35%) and lowest in the Munshiganj district (15.87%). Data indicated that a major proportion of cows significantly (P < 0.05) faced RB problems due to functional causes (34.18%), followed by pathological causes (28.01%), genital tract abnormalities (21.32%), and infectious causes (16.49%). Furthermore, the cows were remarkably (P < 0.001) affected in RB during the summer season and nutritional deficient diseases like milk fever (70%). Age (3-7 years) had a significant (P < 0.001) effect on the RB occurrence (90%) in crossbred cows. However, particular focus should be given to systematic breeding, balanced nutrition, artificial inseminator efficiency, and hygienic inseminating tools to reduce RB incidence in high-yielding crossbred cows.

Human health exposure and risks of arsenic from contaminated soils and brinjal fruits collected from different producers and retailers levels

A quantitative assessment was attempted to determine concentrations of total arsenic (As) in farmer's field soils and fruits of brinjal collected from two famous brinjals producing Upazila's, namely Melandaha and Islampur of Jamalpur district, Bangladesh. The study also evaluated cancer and non-cancer health risks for both males and females caused by dermal exposure of soils and dietary intake of brinjal grown in farmers' fields and sold at different markets of four country districts. The study findings revealed that 75% of soil sampling locations had enrichment factor (EFc) values > 1.5, indicating the anthropogenic sources of As, and 50% of the sites possessed EFc values within the range of 2.0-5.0 indicated moderate enrichment of As. The mean concentrations of As in brinjal grown in farmers' fields and retailers of different markets of four districts were 0.18 and 0.39 µg g^-1, respectively. The soils of the study area exhibited negligible risk in terms of the calculated hazard quotient, hazard index and incremental lifetiame cancer risk (ILCR) values for As due to dermal and ingestion exposures. In contrast, the same values for As due to the dietary intake of brinjal were thousands of times greater than the threshold level in 40% of farmers' field and all retailers' levels samples. Compared to the producer/farmers' field samples, the calculated average non-carcinogenic and carcinogenic health risks were more than twice in samples collected from different retailers. The present study suggests further pinpoint investigation of potential entry routes of As in the supply chain through future traceability studies.

X-Ray absorption spectroscopy on airborne aerosols

Here we demonstrate a method for performing X-ray absorption spectroscopy (XAS) on airborne aerosols. XAS provides unique insight into elemental composition, chemical and phase state, local coordination and electronic structure of both crystalline and amorphous matter. The aerosol is generated from different salt solutions using a commercial atomizer and dried using a diffusion drier. Embedded in a carrier gas, the aerosol is guided into the experimental chamber for XAS analysis. Typical particle sizes range from some 10 to a few 100 nm. Inside the chamber the aerosol bearing gas is then confined into a region of about 1-2 cm³ in size, by a pure flow of helium, generating a stable free-flowing stream of aerosol. It is hit by a monochromatic X-ray beam, and the emitted fluorescent light is used for spectroscopic analysis. Using an aerosol generated from CaCl₂, KCl, and (NH₄)₂SO₄ salt solutions, we demonstrate the functionality of the system in studying environmentally relevant systems. In addition, we show that the detection limits are sufficient to also observe subtle spectroscopic signatures in XAS spectra with integration times of about 1-2 hours using a bright undulator beamline. This novel setup opens new research opportunities for studying the nucleation of new phases in multicomponent aerosol systems in situ, and for investigating (photo-) chemical reactions on airborne matter, as relevant to both atmospheric science and also for general chemical application.

Human health implications of trace metal contamination in topsoils and brinjal fruits harvested from a famous brinjal-producing area in Bangladesh

A study was undertaken to determine the contents of trace metals in 60 topsoils and 80 brinjal fruits samples from a famous brinjal-producing area of Bangladesh using atomic absorption spectrophotometer. The study also looked at soil pollution levels, dietary intake of nutritionally important trace elements, and human health risks from toxic metals induced by dermal soil exposure and consumption of brinjal. The content of Pb, Ni, Cd, Cu, Fe, Mn, and Zn in brinjal fruits harvested from farmer′s fields ranged from 0.204–0.729, 0.031–0.212, < 0.010–0.061, 1.819–2.668, 3.267–5.910, < 0.010–0.866 and 2.160–3.846 µg g^-1, respectively, while the amount of Cr was negligible. The calculated enrichment factors showed that 70, 50, and 25% of soil sampling sites had values in the 2.00–5.00 range for Pb, Zn, and Cd, respectively, while 30% of sites had values > 5.00 for Cd, indicating moderate to significant enrichment of these metals in the soil. The study also revealed that brinjal consumption provides a tiny amount of nutritionally important trace elements required for an adult human. Regarding the computed incremental lifetime cancer risks (ILCR), the study revealed that the values for Pb and Ni in all samples and Cd in 40% of samples were several hundred times higher for males and females than the USEPA threshold level due to oral ingestion of brinjal fruits. In contrast, dermal exposures to soil trace elements were within an acceptable range. The PCA results revealed that the contents of Cd, Pb, Ni, and Cu in soils showed strong positive correlations with those elements present in brinjal. The current study suggests future traceability research, focusing on pinpointing potential entry routes for toxic elements into the vegetable food chain.

Correlation Study between COPD and Heart Failure in Elderly Patient

Heart failure and chronic obstructive pulmonary disease (COPD) are acquiring significant morbidity and mortality and the amalgamation presents many diagnostic challenges. Assessment of cardiac and pulmonary function by echocardiography and pulmonary function tests should be executed in all patients with cautious explanation to avoid misdiagnosis and wrong treatment. Both conditions share overlapping pathophysiological processes. Both functional status and quality of life are greatly influenced by these and associated with high morbidity and mortality rates leading to increase the health-care costs. Although both diseases have been studied extensively, information about the correlation between heart failure and COPD is lacking. Classifying the reason of breathing symptoms among people with both the diseases can be demanding. Therefore it is plausible that a considerable proportion of patients with a diagnosis of COPD have associated heart failure, which ruins unrecognized by primary care physicians or pulmonologists. This study's aim was to assess the relationship between chronic obstructive pulmonary disease and heart failure among elderly patients with chronic cough and dyspnea. This study was done in 100 patient's ≥40 years with a GP (general physician) diagnosis of COPD. Descriptive cross sectional study was carried out in the Department of Medicine, Shaheed Ziaur Rahman Medical College Hospital, Bogra, Bangladesh from November 2011 to April 2012. A total of 100 cases of chronic cough with breathlessness coming into out patient department and admitted into Department of Medicine of Shaheed Ziaur Rahman Medical College Hospital, Bogra, Bangladesh were included according to inclusion and exclusion criteria. Informed written consent was taken from the participants and data was collected by a questionnaire and relevant investigations were done. Data were analyzed with SPSS software and were expressed as mean±SE and significance level of differences among the group was calculated by unpaired student's 't' test. In this study among 100 participating patients with a diagnosis of COPD by their physician, in 24(24%) patients had previously unrecognized heart failure. Pearson Correlation study showed that there is significant positive correlation between FEV₁/FVC and Left Ventricular Diastolic Dysfunction and there is also significant positive correlation between FEV₁/FVC and Total Left Ventricular Dysfunction. By this study we recommend that evaluation and assessment of cardiac status is very important in elderly patients with COPD.

Proportion and Pattern of Central Nervous System Involvement in Acute Leukemia on Diagnosis

The most common malignant neoplasm in Childhood is Leukemia which is about 41% of all malignancies. Incidence of CNS involvement is less than 5% in Acute Lymphoblastic Leukemia and 6-29% in Acute Myeloblastic Leukemia at Diagnosis. For Successful treatment of childhood leukemia it is mandatory, to give sufficient therapy directed to the CNS to treat sub clinical or overt CNS Leukemia. Without Central Nervous System- Directed therapy, relapses originating from the CNS in up to 75% cases. For this purpose it is crucial to find out the CNS involvement in acute leukemia at diagnosis. This study was conducted to find proportion and pattern of central nervous system involvement (central nervous system manifestation and/or cerebrospinal fluid findings) in acute leukemia at diagnosis in Bangladesh. A cross sectional study was conducted from May 2012 to November 2012 in the Department of Pediatric Hematology and Oncology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Total 50 samples were included those having age <15 years newly diagnosed with acute leukemia by purposive sampling. Common age group 1-5 years (48%), 32 patients (64%) were male and 18 patients (36%) were female. Out of 32 male patients 4 patients presented with CNS manifestation and among 18 female patients 2 patients presented with CNS manifestation. There is no association between sex and CNS presentation (P value 0.89). 25 (50%) patients had total leukocyte count >11,000-1,00,000. Twelve (24%) patients had total leukocyte count <4,000. Eight (16%) patients had total leukocyte count 4,000-11,000, and rest 05(10%) patients had leukocyte count >1,00,000. Proportion of CNS manifestation was found 6/50 patients. Eight (8) patients were suffering from AML and 42 patients were suffering form ALL. Among 8 AML patients 1 (11.1%) patient had CNS manifestation and Among 42 ALL patients 5(11.1%) patients had CNS manifestation. Out of 6 patients with CNS manifestation, 2 (04%) patients presented with clinical manifestation, and 5(10%) had positive CSF findings. Pattern of CSF finding of 50 leukemic children CNS-1 90%, CNS-2 02%, CNS-3 08%, and no patients had traumatic lumber puncture with concomitant presence of blasts cells. There is significant association was found between hyper leukocytosis and CNS manifestation (p=0.138) but there is no statistically significant association between positive CSF findings and neurological findings (p=0.082). At conclusion, CNS manifestation is not uncommon (6/50 patients) was found in acute leukemia at diagnosis. So, every patient of acute leukemia should be examined carefully for CNS involvement along with CSF cytospin.

Study on Alanine Aminotransferase in Patients of Type 2 Diabetes Mellitus

Type 2 Diabetes mellitus (DM) is associated with various types of liver disorders including elevated liver enzymes. This study was carried out to observe hepatocellular injury in type 2 Diabetes mellitus as evidenced by raised Alanine aminotransferase (ALT) among the type 2 Diabetes mellitus patients and to find out association between elevated ALT and glycaemic control. This was a descriptive cross-sectional comparative study carried out in Department of Medicine, Rajshahi Medical College Hospital and Rajshahi Diabetic Association Hospital, Rajshahi, Bangladesh from July 2009 to June 2010. One hundred (100) diagnosed type 2 diabetic patients according to WHO criteria and 30 apparently healthy people of both sexes were included. Age of the study people were >40 years. All of those study population were free from taking any hepatotoxic drugs, inj. Insulin, alcohol and preexisting liver disease. Detailed History, thorough clinical examination and relevant investigations were done for exclusion. The frequency of abnormal ALT, Serum bilirubin, Aspartate aminotransferase (AST), Alkaline phosphatase, Prothrombin time and Serum albumin were 30%, 6%, 7%, 6%, 54% and 12% respectively in type 2 diabetic patients and 3.3%, 00%, 00%, 6.7%, 10% and 3.3% respectively in normal people. Serum ALT (U/L) level (mean±SD) of the type 2 diabetic patients and normal people were (39.00±24.21) and (28.26±6.67) respectively. This difference is highly significant (p<0.001). Elevated serum ALT level of type 2 diabetic patients showed positive association with increased Body mass index (BMI) (p<0.05) and poor glycaemic control (p<0.05) and fatty liver (p=0.055). So, a high proportion of patients with type 2 diabetes mellitus have raised serum Alanine aminotransferase level. Elevated serum ALT level was also associated with high BMI, poor glycaemic control and fatty liver which may be a marker of NAFLD and insulin resistance.

Unrecognized Heart Failure in Elderly Patient with COPD

Both of heart failure and chronic obstructive pulmonary diseases are in the elderly. They have an important impact on quality of life and functional status, show high morbidity and mortality rates and lead to extensive health-care costs. Although both diseases have been studied extensively, information about the prevalence of heart failure in stable chronic obstructive pulmonary disease (COPD) patients is lacking. For people who have both the diseases, identifying the cause of breathing symptoms can be challenging. It seems therefore plausible that a considerable proportion of patients with a diagnosis of COPD have concomitant heart failure, which remains unrecognized by primary care physicians or pulmonologists. The main aim of this study was to assess the prevalence of heart failure in patients with a diagnosis of chronic obstructive pulmonary disease. The prevalence of previously unknown heart failure was assessed in 100 patients ≥40 years with a GP (General physician) diagnosis of COPD, in a stable phase of their disease. This descriptive cross sectional study was carried out in the Department of Medicine, Shaheed Ziaur Rahman Medical College hospital, Bogra, Bangladesh from November 2011 to April 2012. A total of 100 cases of chronic breathlessness coming into out patient department and admitted into Department of Medicine of Shaheed Ziaur Rahman Medical College Hospital, Bogra were included based on inclusion & exclusion criteria. After taking informed written consent data was collected by a questionnaire and relevant investigations were done. Then collected data was analyzed and were expressed as mean ±SE and statistical significance of difference among the group was calculated by unpaired students 't' test. In this study we founded among 100 participating patients with a diagnosis of COPD by their physician, in 24 (24%) patients had previously unrecognized heart failure. Therefore, by this study we recommend that evaluation and assessment of cardiac status is very important in elderly patients with COPD.

Childhood Adversities as Risk Factors and Persistence of Suicidal Behavior: A Descriptive Cross-Sectional Study

Suicide is one of the important cause of death worldwide. The precise effect of childhood adversities as risk factors for the onset and persistence of suicidal behaviour are not well understood. A descriptive cross sectional study was carried out in the department of Psychiatry, Cumilla Medical College, Cumilla, Bangladesh. All cases were selected from patients attending at Cumilla Medical College hospital and Private Hospitals in Cumilla City from April 2017 to September 2018. We found out the association between childhood adversities and suicidal behaviour over the life course and delineated the types of suicidal behavior. Total 120 cases were included in the study. Respondents provided socio-demographic and diagnostic information, childhood adversities as well as an account of suicide-related thoughts and behaviours. A participation rate was 77.5% female. Of 120 suicidal behavior participants physical abuse was 2.5%, sexual abuse was 16.67%, parental death was 5%, parental divorce was 2.5%, other parental loss was 4.17%, family violence was 5%, physical illness was 1.67%, financial adversity was 3.33% and composite adversity was 59.16%. Among childhood adversities participants suicidal ideation was 70%, suicidal plans was 15.83%, suicidal attempts was 45%, ideators only proceeded to plans was 22.5%, ideation to attempt was 63.33%, planned attempts was 10.83% and impulsive attempts was 52.5%. Among suicidal behavior participant's psychiatric disorders were 65%. Where neurotic disorders were 17%, psychotic disorders were 13%, personality disorders were 44% and others disorder was 26%. Most of the suicidal behavior patients were female 77.5% and age group of 18-24 years. Childhood sexual abuse emerged as a particularly robust risk factor for suicide attempts in younger participants. Childhood physical and sexual abuse emerged as risk factors for the emergence and persistence of suicidal behaviour, especially in adolescence. Two or more childhood adversities were associated with a three fold higher risk of lifetime suicide attempts. Childhood adversities are main risk factors for the onset and persistence of suicidal behaviour. The risks being are the greatest in childhood, adolescence and early adult. A longitudinal follow-up study is required to give a more reliable in Bangladesh.

Congenital Eventration of Diaphragm Presenting As Diaphragmatic Hernia: A Case Report

Eventration of diaphragm is an abnormal elevation of diaphragmatic musculature while retaining normal attachments to the sternum, ribs and dorsolumber spine. It is a rare anomaly where the continuity of diaphragm remains intact. Pathological process can affect either all or only a portion of hemidiaphragm. Symptoms vary according to size of the defect. Large defect may mimic diaphragmatic hernia. The present case represents a full term female newborn that developed respiratory distress, cyanosis and feeding difficulties since 1st day of life. Clinical features and chest imaging of this case was assumed to be left sided diaphragmatic hernia which was found wrong in the operation theater. She was found to have left sided eventration of diaphragm to create symptom. Successful plication of ipsilateral diaphragm was done on 13th day of life. Supervised post operative ventilatory support along with other postoperative care improved the condition of this neonate. A large defect with eventration of diaphragm may be life threatening but a timely good management can save neonate from such condition.

Iron Deficiency and Iron Deficiency Anemia in Women with Bronchial Asthma

This case control study was conducted in the out patient department (OPD), Enam Medical College & Hospital (EMCH), Dhaka, Bangladesh from 1st January 2017 to 31st December 2017. The aim of our study was to find the possible association between serum iron state and iron deficiency anemia with bronchial asthma in women. We investigated 40 diagnosed female cases of well controlled bronchial asthma and 20 healthy female as control. In both groups complete blood count (CBC) with peripheral smear was done, C-reactive protein (CRP), serum iron, serum ferritin, and serum total iron binding capacity (TIBC) was measured. We found asthma cases had lower hemoglobin than control (mean±SD 10.92±1.34 vs. 12.30±0.73, p value 0.013), serum iron and serum ferritin were significantly lower (p value 0.016 and 0.000 respectively) and TIBC was higher (p value 0.000) in asthmatic cases as compared to controls. Non anemic asthmatics showed significant lower serum ferritin compared with non-anemic healthy controls (p value 0.005). So we conclude that iron deficiency anemia is more prevalent in asthmatic women as compared to healthy controls.

Brachial Plexus Schwannoma: A Case Report with Emphasis on Imaging

Brachial plexus tumors are rare. Schwannomas are benign nerve sheath tumors and only about 5% arise from brachial plexus. Diagnosis of these tumors are challenging for radiologists as well as clinicians as they are rare and the anatomy of the neck is complex. We report a case of a middle aged woman who was admitted in Mymensingh Medical College in Neurosurgery Department on 15th December 2017 with right supraclavicular swelling; based on the clinical findings was provisionally diagnosed as supraclavicular lymphadenopathy; Ultrasonography and Magnetic Resonance Imaging suggested schwannoma. Complete excision of the mass through supraclavicular approach showed the origin of it from the brachial plexus, which subsequently was confirmed to be a schwannoma with histopathology.

Enzyme Immobilization on Metal-Organic Framework (MOF): Effects on Thermostability and Function

MOFs are porous materials with adjustable porosity ensuing a tenable surface area and stability. MOFs consist of metal containing joint where organic ligands are linked with coordination bonding rendering a unique architecture favouring the diverse applications in attachment of enzymes, Chemical catalysis, Gases storage and separation, biomedicals. In the past few years immobilization of soluble enzymes on/in MOF has been the topic of interest for scientists working in diverse field. The activity of enzyme, reusability, storage, chemical and thermal stability, affinity with substrate can be greatly improved by immobilizing of enzyme on MOFs. Along with improvement in enzymes properties, the high loading of enzyme is also observed while using MOFs as immobilization support. In this review a detail study of immobilization on/in Metalorganic Frameworks (MOFs) have been described. Furthermore, strategies for the enzyme immobilization on MOFs and resulting in improved catalytic performance of immobilized enzymes have been reported.

Flavonol biosynthesis by nonheme iron dioxygenases: A computational study into the structure and mechanism

Plants produce flavonol compounds for vital functions regarding plant growth, fruit and flower colouring as well as fruit ripening processes. Several of these biosynthesis steps are stereo- and regioselective and are being carried out by nonheme iron enzymes. Using density functional theory calculations on a large active site model complex of flavanone-3β-hydroxylase (FHT), we established the mechanism for conversion of naringenin to its dihydroflavonol, which is a key step in the mechanism of flavonol biosynthesis. The reaction starts with dioxygen binding to the iron(II) centre and a reaction with α-ketoglutarate co-substrate gives succinate, an iron(IV)-oxo species and CO₂ with large exothermicity and small reaction barriers. The rate-determining reaction step in the mechanism; however, is hydrogen atom abstraction of an aliphatic CH bond by the iron(IV)-oxo species. We identify a large kinetic isotope effect for the replacement of the transferring hydrogen atom by deuterium. In a final step the OH and substrate radicals combine to form the alcohol product with a barrier of several kcal mol^-1. We show that the latter is the result of geometric constraints in the active site pocket. Furthermore, the calculations show that a weak tertiary CH bond is shielded from the iron(IV)-oxo species in the substrate binding position and therefore the enzyme is able to activate a stronger CH bond. As such, the flavanone-3β-hydroxylase enzyme reacts regioselectively with one specific CH bond of naringenin by avoiding activation of weaker bonds through tight substrate and oxidant positioning.

Primary Non-Hodgkin Lymphoma of Sphenoid Sinus Involving Cavernus Sinus and Clivus with Isolated 3rd Nerve Palsy

Lymphomas are group of malignant neoplasm having origins from lymphoreticular cells. B cell Non Hodgkin Lymphoma (BNHL) of sphenoid sinus as primary site for lymphomas are very rare and whenever involves comes usually with ocular manifestations. The proximity of the lesion to optic nerve and cavernous sinus present a high risk of developing unilateral ophthalmoplegia or even blindness. The vast majority of cases of localized sphenoid sinus lymphomas are usually curable to surgery, chemotherapy alone or combination of both, sometimes radiotherapy. Here we report a case of 58 years old male attended at Bangabandhu Sheikh Mujib Medical University (BSMMU) on 9th February 2017 at 9:00 AM having headache and gradually developing ptosis in left eye over 15 days. MRI of brain revealed homogeneously enhancing lesion occupying sphenoid sinus, clivus extending towards left cavernous sinus. Gross total resection of tumor was achieved by endoscopic endonasal approach. Histopathology revealed non-Hodgkin lymphoma and immunohistochemically it was positive for CD 20, CD 45, CD 79 and BCL 2, strongly compatible with diffuse large B cell lymphoma. Treatment with R-CHOP regimen following surgery resulted in initiation of improvement of the condition of the patient. Primary B cell Non-Hodgkin Lymphoma (PBNHL) of the sphenoid sinus is a rare entity which can be perplexing and misleading for a surgeon until the histopathological proof is in hand. Early diagnosis with strong suspicion of sphenoid lymphoma in mind during workouts and timely management, close monitoring and follow ups have high potential for cure and longer disease-free survival of the BNHL patients.

Influence of green grass-based diets on growth and reproductive performance in dairy heifers

The objective of this study was to monitor the changes in growth, dry matter intake, and blood profiles (nutrition and reproductive hormones) of dairy heifers in response to green grass-based diets. Twelve crossbred heifers were equally divided into group 1: rice straw and concentrate; group 2: rice straw, green grass, and concentrate; group 3: green grass and concentrate; group 4: green grass, soybean hay, and concentrate. Dry matter intake in group 4 was found 6% higher (P < 0.05) than group 1. Negative body weight gain was found in group 1 and group 2 showed 14% higher body weight gain per 30 days compared to groups 3 and 4 (P < 0.05). Heifers in group 4 had significantly (P < 0.05) higher heart girth gain, serum albumin, urea, and blood urea nitrogen than the heifers in other groups. Endocrine parameters were found similar among groups. Overall, supply of green grass especially a mix of leguminous and non-leguminous was found advantageous in heifer feeding.

Psychiatric Disorders in Drop out from Educational Attainment Attending Mental Health Facilities: A Descriptive Cross Sectional Study

Studies of the impact of mental disorders on educational attainment are rare. Mental disorders, those beginning in childhood or adolescence may increase the risk of early drop out from education. The latter has been shown to have adverse life-course consequences on individuals such as greater demand on social welfare entitlements. A descriptive cross sectional study was carried out at the department of Psychiatry, Comilla Medical College, Comilla, Bangladesh. All cases were selected from patients attending at Comilla Medical College Hospital and Private Mental Health Facilities in Comilla City from March 2015 to February 2016. We found out the psychiatric disorders and socio-demographic status of patients with educational drop out over the early life course. A total of 50 dropout patients aged 10 to 30 years who fullfiled the enrolment criteria included in the study. Sociodemographic questionnaires, diagnostic information (DSM-5 and ICD-10) as well as an account of a various level of education were used as research instruments. The Frequency tables, summary tables and appropriate graphs were prepared to describe the population characteristics and study finding. The most of the psychiatric morbidity presents in male (62%) and age group of 18-24 years (54%). In this study, anxiety disorders was 8%, behaviour/ impulse control disorders was 8%, mood disorders was 16%, substance use disorders was 24%, schizophrenia spectrum disorders was 12% and composite psychiatric disorders was 32%. Among drop out patient's non- completion of primary education was 14%, non-completion of secondary education was 20%, non- completion of higher secondary education was 24%, not entry to tertiary education was 12% and non-completion of tertiary education was 30%. Among behaviour/impulse control disorders non-completion of primary education was 6%, substance use disorders non-completion of higher secondary education was 10%, mood disorder both non-completion of higher secondary education and non-completion of tertiary education were 6%. Among composite psychiatric disorders non-completion of secondary education, non-completion of higher secondary education and non-completion of tertiary education were 8%, 6% and 12% respectively. Onset of mental disorders and subsequent drop out from education was found in this study. Further multi-centered prospective and population-based studies should be designed to find out the exact situation.

Rice Vision for Bangladesh: 2050 and Beyond

CORRECTION: Due to a number of formatting and layout issues, the PDF of this paper was replaced on 10th October 2016.Combined efforts of farmers, rice scientists, extension personnel and Government of Bangladesh have yielded clean rice growth rate of 0.34 million ton (MT) year-1 during 2009-10 to 2013-14 in the country. In 2014-15, the country acquired a rice surplus of about 2 MT. However, maintaining the current surplus of rice in the coming decades is a great challenge. Authentic estimation of future rice requirement and future resource availability would guide to way forward. This paper presents rice vision for Bangladesh leading to 2050 and beyond. In this study, secondary data from different government-owned statistics and research institutes were collected, analyzed and synthesized to develop models and/or model parameters to generate outputs such as future population, rice production and rice requirement. Population of Bangladesh will reach 215.4 million in 2050, when 44.6 MT of clean rice will be required. With the pace of rice-production-increase in the last five years, production can reach 47.2 MT, having a surplus of 2.6 MT in 2050. The study sets 2.6 MT as the target for clean rice surplus every year leading to 2050 and beyond. Several hurdles, such as increasing population, decreasing resources and increasing climate vulnerability, can hinder achieving the target. Three major interventions?accelerating genetic gain, minimizing yield gap and curtailing adoption lag?are proposed to break the barriers to achieve the target. Major challenges to implement the interventions include shrinking net cropped area, decreasing availability of irrigation water and increasing pressure on soil fertility. Smart technology such as, location specific variety, profitable cropping sequences, innovative cultural management, and mechanization coupled with smart dissemination using multiple means would ease production barriers. We recommend a number of measures, such as, guaranteeing a minimum cropped area, accelerating the rate of genetic gain in varietal development and intensifying collaboration among the stakeholders to reduce adoption lag of newly released promising rice varieties, to achieve the rice vision of Bangladesh leading to 2050 and beyond.Bangladesh Rice j. 2015, 19(2): 1-18

Protection Effect of Vaxxitek HVT + IBD Vaccine Against Infectious Bursal Disease in Broiler Chickens

The very virulent infectious bursal disease virus (vvIBDV) infection cause constant and frequent outbreaks of IBD. In order to prevent the disease caused by vvIBDV, moderate-virulent live vaccines are usually used in broilers, but these vaccine influence the immune system of chickens and cause the immunosuppression. VAXXITEK® HVT+IBD bivalent vaccine, a novel vaccine produced by Merial Company, is the recombinant vaccine generated by inserting IBDV VP2 gene into the HVT genome. The recombinant vaccine could prevent Marek’s disease and IBD of chickens at the same time after vaccinated by the subcutaneous route at 1-day-old. The objective of this study was to evaluate protection effect of this new vaccine against IBD in broilers. The results of the lab and field immunization trial showed that the vaccination of VAXXITEK® HVT+IBD vaccine did not damage the bursa of broilers; the level of IBD antibody of the VAXXITEK® HVT+IBD vaccination groups was higher than IBD-BLEN® vaccination groups at 21-day-old; the protection effect of the VAXXITEK® HVT + IBD vaccination groups was better than IBD-BLEN® vaccination groups, especially at 21-28 day. The results indicated that VAXXITEK® HVT + IBD vaccine could provide better protection to broiler chickens against IBD.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19102 Progress. Agric. 24(1&2): 69 - 78, 2013

Influence of body mass index on low back pain

Low back pain (LBP) is a common problem affecting 70% of the population in the developed countries and prevalence is also increasing in the developing countries. We conducted a clinic based cross-sectional study in the city of Dhaka and Chittagong during the period of January 2009 to December 2011. Participants (n=357) were interviewed and examined through a structured questionnaire after a non purposive sampling to explore the influence of body mass index (BMI) on LBP. BMI was assessed by the equation weight (Kg)/hight² (m²) and LBP was assessed by modified visual analogue scale. Association between LBP and BMI was tested by Chi-square test. Among 357 patients the incidence of LBP was common in the age group between 40-59 years and it was 172(48.17%) followed by 60-79, 20-39 and ≥80 years group with 21.29%, 17.65% and 12.89% respectively. Female presented more with LBP, i.e. 196(54.91%) than the male 161(45.09%). The more study population was found to have BMI within normal range, i.e. 167(46.78%). This was followed by overweight group which amounted 137(38.37%) while the obese group was the least, i.e. 53(14.85%). Maximum study population presented with severe LBP which amounted 140(39.22%) while others presented with moderate and mild LBP and amounting 118(33.05%) and 99(27.73%) respectively. Among the normal BMI group most patient presented with mild pain (n=82) followed by moderate (n=55) and severe (n=30) pain. Participants with overweight presents with severe pain mostly (n=58) but obese participants presented with severe low back pain (n=25). Statistically the association of LBP with BMI was found to be highly significant (p<0.0001). In this study, 137(46.78%) participants of normal BMI presented with LBP but majorities (n=82) presented with mild LBP and overweight and obese participants mostly presented with severe LBP. On the basis of these findings, careful evaluation of risk factors and deliberate assessment of the therapeutic as well as preventive measure for the management of patient of LBP is highly recommended.

Hyperemesis gravidarum and fetal gender: a retrospective study

This retrospective study of 9,980 women who delivered at the James Paget Hospital, Norfolk, UK, over 5 years, aimed to primarily determine whether the incidence of hyperemesis gravidarum (HG) is higher in the presence of a female fetus. The results showed that more women with HG had a female fetus compared with women without HG. Also found was that heavy ketonuria was more prevalent in women with a female fetus compared with women with a male fetus, and the mean number of admissions per woman was also higher in women with a female fetus compared with women with a male fetus. It can be concluded that women presenting with HG are more likely to have a female fetus and that women with HG and a female fetus tend to a higher level of ketonuria and an increased number of hospital admissions.

Kinetic analysis of the active site of an intracellular beta-glucosidase fromCellulomonas biazotea

Purified beta-glucosidase fromCellulomonas biazotea had an apparentK (m) andV for 2-nitrophenyl beta-D: -glucopyranoside (oNPG) of 0.416 mmol/L and 0.22 U/mg protein, respectively. The activation energy for the hydrolysis of pNPG of beta-glucosidase was 65 kJ/mol. The inhibition by Mn(2+) vs. oNPG of parental beta-glucosidase was of mixed type with apparent inhibition constants of 0.19 and 0.60 micromol/L for the enzyme and enzyme-substrate complex, respectively. Ethanol at lower concentrations activated while at higher concentrations it inhibited the enzyme. The determination of apparent pK (a)'s at different temperatures and in the presence of 30 % dioxane indicated two carboxyl groups which control theV value. The thermal stability of beta-glucosidase decreased in the presence of 10 % ethanol. The half-life of beta-glucosidase in 1.75 mol/L urea at 35 degrees C was 145 min, as determined by 0-9 mol/L transverse urea gradient-PAGE.

Pharmacological validation of early and late phase of rat mono-iodoacetate model using the Tekscan system

BACKGROUND

Previous pharmacological validations of the rat mono-iodoacetate (MIA)-induced chronic joint pain model were mostly performed by measuring weight-bearing (WB) deficit with an incapacitance tester. However, conventional incapacitance testers have several drawbacks including restrain stress on animal and sole use of hind limbs WB.

OBJECTIVES

The aim of the present study was to compare pharmacological sensitivity of the early (up to 1 week after MIA) versus late (between 2 and 4 weeks after MIA) phase of the rat MIA model using a highly sensitive tactile pressure measurement system (Tekscan(®)), which can measure weight borne by all four limbs and the tail in a non-restrained animal.

METHODS

The Tekscan(®) WB measurement system was used in MIA rats to examine the acute and chronic dosing effects of drugs that targeted different mechanisms. Electrophysiological recordings from joint afferents and biochemical analysis of synovial fluid were also performed.

RESULTS

Dexamethasone, duloxetine and morphine significantly alleviated WB deficits in the Tekscan(®) system during both early and late phase of the MIA model while celecoxib and naproxen alleviated WB deficit only during the early phase. Similarly, naproxen was able to inhibit spontaneous neuronal activity from MIA joint afferents only during the early phase. Finally, concentrations of prostaglandin E(2) in synovial fluid were elevated only during the early phase of the rat MIA model.

CONCLUSIONS

Our pharmacological validation studies using the Tekscan(®) system along with electrophysiological and biochemical results suggest different mechanisms for early and late phase of MIA-induced chronic joint pain in rat.

Comparative study between Pap smear and visual inspection using acetic acid as a method of cervical cancer screening

This prospective study was done for the comparison of visual inspection using acetic acid (VIA) and Pap smear as a method of cervical cancer screening. This study was also done to determine the proportion of women screened positive with VIA and proportion of women screened positive with Pap smear. Another aim was to compare the sensitivity and specificity of VIA and Pap smear. A total of 300 women attended to the outpatient gynecologic clinic and cervical cancer screening programme at Bangabandhu Sheikh Mujib Medical University (BSMMU) were included. On VIA, 23 out of 300 women screened had aceto-white lesions. On Pap smear, 14 out of the 300 women had ASCUS or worse lesions. Of the 300 enrolled women, 11 were positive on both VIA and cytology; 12 were positive on VIA only; and 3 were positive on cytology only. Those women (n=26) who showed positive test result with either VIA or Pap smear or both tests were further subjected to colposcopy directed biopsy. Histology was taken as gold standard to compare the performance of VIA and cytology (Pap's smear). Histological diagnosis of CIN/cancer was made in 18 Positive cases out of the total 26 patients who underwent biopsy. Pap smear picked up 10 out of the 18 biopsy-proven cases whereas VIA could identify 17 out of the 18 CIN/carcinoma cervices. VIA was more sensitive (94.44%) than pap smear (55.55%), which was statistically significant. However, the specificity of VIA was slightly lower (97.87%) than that of cytology (98.58%). The PPV of VIA was 73.91% versus 71.42 % for Pap smear.

Different doses of atropine on heart rate fluctuations during reversal of neuromuscular blockade

It was a prospective comparative clinical study carried out in the Department of Anaesthesia, Combined Military Hospital (CMH), Dhaka, to evaluate the heart rate changes during reversal of neuromuscular blockade by using 3 different doses of atropine (in a mixture with neostigmine) and thereby detect comparatively safer dose. Sixty patients of ASA (American Society of Anesthesiologists) grade I and II physical status were divided equally into 3 groups. Neostigmine 0.05 mg/kg body weight mixed with atropine 0.02, 0.015 and 0.01 mg/kg body weight given intravenously in group A, B and C respectively during reversal. The 3 groups were compared in age, sex, body weight, and ASA grades, but there was no significant difference (p>0.05) between 3 groups. It is revealed that in Group C (atropine at a dose of 0.01 mg/kg with neostigmine), heart rate affected very little but salivary and tracheobronchial secretions were more. One of them had laryngospasm which was managed conservatively. In Group B (who received atropine 0.015 mg/kg) incidence of tachycardia observed was less than Group A (who received atropine 0.02 mg/kg). The patients of this group also had some salivary secretions but less than group C. Tachycardia was most marked in Group A but had minimum salivary secretions. Statistical analysis of heart rate changes in different times among the 3 Groups was significant (p<0.05). It was highly significant (p<0.01) in 1 minute after reversal. So relatively lower dose (0.015 mg/kg) of atropine with neostigmine than the conventional dose (0.02mg/kg) can be used to decrease tachycardia during reversal of neuromuscular blockade especially in haemodynamically unstable patients.

Comparison between tramadol hydrochloride & nalbuphine hydrochloride in the treatment of per-operative shivering after spinal anaesthesia

Per-operative shivering following spinal anaesthesia is a common problem in the operation theatre. Adequate management of shivering during operation is one of the goals of anesthesiologists for the benefit of the patient. Because there are many unpleasant and harmful effects caused by shivering in many patients especially respiratory and cardiac disease patients. For this reason aggressive and optimal treatment of per-operative shivering is essential to reduce the morbidity of the patients. Our observations were that occurrence of shivering was more in younger patients than older patients, thin patients than obese patients, anxious patients than non-anxious patients and more frequent in patients who received vasoconstrictor drugs, administration of fluid at running rate just before or during operation, administration of cold local anaesthetic agents (by taking drug from the freeze) into subarachnoid space. And shivering was better managed by administration of nalbuphine HCl and surface skin warming (wrapping of the skin). There are many studies regarding the incidence, prevention & treatment of post-operative shivering but there is no study regarding the incidence & treatment of per-operative shivering by nalbuphine following spinal anaesthesia. This study was designed to compare the anti-shivering efficacy and side effects (Nausea, Vomiting, and Somnolence) of tramadol hydrochloride with that of nalbuphine hydrochloride in the treatment of per-operative shivering following spinal anaesthesia. This study was also done to observe the incidence of shivering during operation following spinal anesthesia.

Is gross total removal necessary for paediatric posterior fossa tumour?

This prospective study was done in Neurosurgery department, Dhaka Medical College Hospital. It was conducted from December 2002 to October 2005. During this period 40 paediatric posterior fossa tumour patients was admitted. The mean age of the patients were 8.31+/-3.1 years ranging from 3.5 to 15 years. The main complaints were headache with vomiting (100%), dimming of vision (70%), Ataxia (52.5%), Blindness (25%). All cases had a definite diagnostic investigation at the time of admission. Plain x-ray skull was done in all patients followed by MRI scan (42.5%), CT scan (37.5) and both CT and MRI scan (20%). In all cases CSF diversion (VP shunt) were instituted. All patients were operated by suboccipital craniectomy followed by gross total removal of tumour in (62.5%) and subtotal removal in (37.5%). In all cases diagnosis was confirmed by histopathological examination. In cases of subtotal resection, symptoms (headache, vomiting) appeared during 7-9 months follow up period in (7.5%) and subsequent follow up in (12.5%). But in gross total removal symptoms appeared in one case (2.5%) in 13-15 months follow up period.

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.

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.