Deep breathing exercises in easing educational stress among Indian high school students

In this educational landscape, the pervasive issue of stress among higher secondary students has emerged as a serious matter. Acknowledging the challenges posed by educational stress, this research explores holistic and accessible interventions, with a focus on the promising avenue of deep breathing exercises known for their effectiveness in promoting relaxation and reducing stress. The study employs a quasi-experimental design, comparing an experimental group engaged in daily deep breathing exercises with a control group following a regular routine. Sixty higher secondary students in Visnagar participate through purposive sampling, adhering to specific inclusion criteria. The intervention includes a pre-tested questionnaire to assess stress levels, the implementation of daily deep breathing exercises in the experimental group, and a post-intervention stress level reassessment in both groups. The findings reveal a notable reduction in stress levels post-intervention, particularly in the experimental group practicing deep breathing exercises. Statistically significant reductions in mean stress scores underscore the effectiveness of this intervention, with the experimental group demonstrating a significantly lower mean stress score compared to the control group. This study contributes vital insights into stress management strategies for higher secondary students, highlighting the efficacy of incorporating deep breathing exercises into their routine. The observed reductions in stress levels emphasize the potential benefits of practical stress reduction techniques within the educational milieu.

Effect of aerobic exercise on anthropometric parameters among Indian primary school children

Childhood obesity is a global public health concern with significant implications for long-term health. This study addresses the rising rates of obesity among school-age children (10-12 years) and investigates the effectiveness of aerobic exercise interventions in improving anthropometric parameters, specifically focusing on BMI and mid-arm circumference (MAC). The study emphasizes the role of schools in shaping children's behaviors and aims to contribute empirical evidence to inform health promotion strategies for this demographic. The research employs a quasi-experimental design, involving 60 school-age children in Visnagar, Gujarat, India. The 12-week aerobic exercise intervention, conducted three times a week, comprises activities like running, jumping jacks, and dance routines. Data collection includes sociodemographic information, BMI, and MAC measurements. The study design, participant criteria, and intervention details are carefully outlined. Socio-demographic variables such as age and monthly family income significantly influence BMI, highlighting the importance of considering these factors in interventions. Pretest results show 80% of children classified as overweight, reducing to 58.3% post-intervention. The mean BMI significantly decreases from 24.41 to 22.84 (p < 0.05), indicating the positive impact of aerobic exercise. The study also explores the association between BMI, MAC, and socio-demographic variables through chi-square tests. Data shows the prevalence of overweight and obesity among school-age children and demonstrates the effectiveness of a 12-week aerobic exercise program in improving BMI. Findings align with existing literature on the positive impact of physical activity on weight management in children.

Impact of oil massage on newborn behavioural responses in rural India

The initial weeks of a newborn's life are marked by rapid physiological and behavioural adjustments as the infant adapts to the external environment. This critical period necessitates attentive care, prompting exploration into traditional practices such as oil massage, which holds cultural significance and is believed to enhance neonatal well-being. Despite its prevalence, empirical evidence supporting the efficacy of oil massage remains limited. This study, conducted in a rural setting, aims to bridge traditional practices with evidence-based care, exploring the impact of oil massage on newborn behavioural responses. A quasi-experimental design involving 60 newborns (30 in each group) assessed behavioural responses through a pre and post-test approach. Results indicate a significant improvement in selected behavioural responses among newborns receiving oil massage, emphasizing its potential integration into routine care. The control group showed a pre-test mean of 14.83 (SD = 2.41) and a post-test mean of 16.23, while the experimental group exhibited a pre-test mean of 15.83 (SD = 1.80) and a post-test mean of 26.07. T-test values of 5.194 for the control group and 26.137 for the experimental group were indicative of statistically significant changes. The study contributes insights into neonatal care practices, urging further exploration of contextual intricacies and demographic influences on newborn behaviour.

Knowledge, attitudes and demographic effect on menopausal experiences among Indian rural women

The menopausal experiences of women in selected rural areas of Visnagar, addressing a research gap within cultural and socio-economic landscapes is of interest. The global aging trend was reflected in the 26% representation of women aged 50 and over in the study. Employing a cross-sectional design, 200 menopausal women were sampled through stratified random sampling, emphasizing demographic diversity. Results from a structured Knowledge Questionnaire and a Likert Scale for Attitude revealed that women generally possessed commendable knowledge (mean score 10.94) and positive attitudes (mean score 28.66) toward menopause. Significant associations between age, education, occupation, and income with knowledge and attitudes were uncovered through chi-square tests. This study underscored the need for tailored interventions in rural settings, considering the influence of cultural, regional, and demographic factors on menopausal experiences. The findings contributed to bridging the research gap and emphasized the importance of individualized approaches for promoting the well-being of menopausal women in rural communities.

Exploring eating behaviors, knowledge and attitudes of adolescent Indian girls

Data on the eating behaviors, knowledge, and attitudes of adolescent girls in Visnagar, India, focusing on the prevalence of non-communicable diseases [NCDs] and their association with dietary practices is of interest. Adolescence, a crucial developmental phase, sets the foundation for lifelong health habits, necessitating an understanding of the determinants influencing eating behaviors. The research aims to identify gaps in knowledge, attitudes, and practices [KAP], providing insights for culturally sensitive public health strategies. Through structured questionnaires and Likert scales, data were collected from a purposive sample of adolescent girls [ages 12-18] in a selected school. Descriptive statistics and correlation analyses were employed to assess knowledge, attitudes, and behaviors, considering demographic variables. Non-significant associations were found between these variables and demographics. The mean knowledge score was 25.11, reflecting a moderate level, while the mean attitudes score was 99.54, indicating generally positive attitudes. Adolescent girls demonstrated an overall mean behaviour score of 110.93, with a positive correlation [0.72] between knowledge and behaviors and a stronger correlation [0.99] between attitudes and behaviors. Findings highlight the universal importance of knowledge in influencing eating behaviors and emphasize the need for culturally tailored interventions considering regional influences. The study contributes valuable insights into the interplay of knowledge, attitudes, and behaviors related to eating disorders in adolescent girls, serving as a foundation for targeted public health strategies.

Effect of curry leaves in lowering blood pressure among hypertensive Indian patients

Hypertension, commonly known as high or rising blood pressure, is characterized by a consistently elevated blood arterial pressure. It is a significant medical condition called hypertension raises your risk of developing problems with your heart, brain, kidneys, and other organs. Curry leaves work well as a treatment for high blood pressure. Curry leaves are thought to have a potent therapeutic impact for the treatment of high blood pressure since they are low in salt and high in potassium. Therefore, it is of interest to reduce the level of blood pressure among adults in rural area with the help of curry leaves. According to the statistical analysis, the experimental group's post-test mean score for hypertension was 155 with a standard deviation of 13.892 while the control group's post-test mean score was 162 with a standard deviation of 17.20. The estimated unpaired value of t = 11.07 was deemed to be statistically significant at the p 0.05 level and the mean difference was 7. As a result, the null hypothesis was rejected and the research hypothesis was accepted. Giving Curry leaf powder to patients with hypertension as a consequence was an effective intervention.

Breast feeding practices after normal vaginal and caesarean delivery in Gujarat, India

Breast feeding is the mainspring of child survival, nutrition, development and maternal health. Early initiation of breastfeeding is an extremely important factor associated with the maintenance of long-term breastfeeding practice. Breastfeeding practices can be influenced by a variety of variables such as parity, mode of delivery; body mass index (BMI), breast or nipple abnormalities and behavioural factors are equally as important. The present study was conducted to analyze Breast Feeding Practices after Normal Delivery and Caesarean Delivery at a Tertiary Care Hospital. This cross sectional study was conducted at tertiary care hospital, by Convenient non-random sampling method, which included two groups; Group A: 100 mothers who delivered vaginally Group B: 100 mothers who gave birth through caesarean section (n=100 each). Participants were asked to complete standardized questionnaire consists of information on socio demographic and breast feeding practice. All anthropometric measurements were taken. A semi-structured questionnaire was used to collect data on maternal socio demographic characteristics, breastfeeding knowledge, practices along with source of information regarding breastfeeding and maternal experience. The study results shows that initiation of breastfeeding is most common in normal vaginal delivery (70%) among total 100 subjects of vaginal delivery category and also common in subjects with planned C-section (49%) of 100 subject"s caesarean delivery category. Association between the modes of delivery and initiation of breastfeeding within an hour was statistically significant (p<0.01). The present study indicates that C-sections are linked to higher breastfeeding challenges, greater resource usage, and shorter nursing duration.

Boosting awareness on healthy habits among school children in north Gujarat, India

Hygiene is the science of health and its maintenance. Hygiene status of children is an index of national investment in the development of its man power. It is influenced by social, familial and individual factors as well as the children's knowledge of health on personal hygiene, comfort and basic needs. The utility of games is as a teaching strategy of health professionals. The main objectives of the study were to assess existing level of awareness regarding healthy habits among school children and to check the effect of Modified snake & ladder game in improving the awareness of children regarding healthy habits. Research design selected for this study was pre experimental one group pretest posttest design with a sample size of 60. Samples of the study were given opportunity to play and earn awareness through the modified snake & ladder game. Their awareness was assessed before and after the game section. Data was analyzed by using descriptive and inferential statistics such as mean, standard deviation and chi square test. In data analysis the mean of pre-test score was 13.83 and mean of post-test score was 18.63. The mean difference was 4.8. The standard deviation of pre-test stress score was 01.07 and post-test stress score was 01.60. The calculated' 't' value was 21.24, which was greater than the table value(1.67).The study concluded that snake and ladder game was effective in improving the awareness of school children on healthy habits.

Effect of outdoor games among school children in Northern Gujarat, India

Outdoor play works as an important tool for the children education. Providing a natural learning environment for children helps them to have an active and fulfilling life. Also, higher levels of attention and well-being are promoted when children play in green outdoor spaces. The importance of play for children's healthy development is grounded in a strong body of research. The study used an experimental research methodology, and data was obtained from 60 school-aged children using a purposive sample strategy and a checklist. The mean, standard deviation, and chi square test were used to analyze the data. After giving act out method, majority (85%) of the school age children had adequate knowledge, 15% of the school children had moderate knowledge regarding outdoor games and its importance. In data analysis the mean of pretest score was 6.43 and mean of post test score was 15.88. The mean difference was 9.45. Post test mean was more than pretest mean, which indicate the effectiveness of actout method on deficiency of outdoor game among school children. The standard deviation of pretest knowledge score was 3.9; the post test knowledge score was 2.47. The computed 't' value was 16.1, the DF was 59, and the P value was 1.67, all of which are significant. Religion, monthly income, and the age of the children all had an impact on the calculated chi square value. According to the findings of this study, the act out method was successful in boosting understanding about the lack of outdoor games among school-aged children.

Effect of bibliotherapy on reducing anxiety among pre-operative patients in Gujarat, India

Numerous studies have shown that patients can have preoperative anxiety in mild, moderate, or severe forms. A supplemental tool to a disease's clinical treatment is bibliotherapy. This approach includes the core ideas of cognitive behavioral therapy and offers exercises meant to assist readers in overcoming unpleasant emotions. Therefore, it is of interest to evaluate how well bibliotherapy reduced pre-operative patients' anxiety. For the experimental group (30) and control group (30), a sample of 60 preoperative patients who had been determined to have considerable levels of anxiety was chosen. The Hamilton Anxiety Rating Scale is used to measure patient anxiety. Prior to surgery, bibliotherapy was given to the experimental group's sample twice daily for around 20 minutes. No intervention was given to the control group. The study's findings showed that the experimental group's mean percentage anxiety score at the pre-test was 80.10 percent, whereas the control group's mean percentage anxiety score was 85.66 percent. After the test, the experimental group's mean anxiety score was 50.66 percent, while the control group's mean anxiety score was 83.20 percent. It is evident that bibliotherapy was successful in lowering pre-operative patients' anxiety levels. Nurses can utilize this non-pharmacological technique to help patients feel less anxious about surgery and experience fewer post-operative problems.

Effect of Beta vulgaris extracts on dysmenorrhea among adolescent girls

Dysmenorrhea is painful menstrual periods which are caused by uterine contractions. The ache is commonly felt in the pelvic or lower abdomen around the time menstruation begins. Periods aren't the best time for a woman to feel strong and energized. With all of the blood loss, cramps, and exhaustion, finding enough excitement to get through the day's responsibilities is difficult. Vulgaris Beta Potassium and nitrates, both of which are necessary for blood pressure regulation, are abundant in juice. For energy, only 50ml of beet juice is required. The analysis of data was done by descriptive and inferential statistics. The study identified that 46.66 % had moderate pain, 33.33 % had mild pain and none of them had severe pain for the pre- experimental group. The study result shows that the pre-test mean value for is 5.91 and pre-test SD 0.96. The post-test mean value is 2.86 and post-test SD is 1.04. The mean difference is 3.05. The calculated 't' value is 16.85 is higher than the table value 1.67. The study concluded that Beta vulgaris juice found to be effective non-pharmacological measures to reduce dysmenorrheal among adolescent girls.

Awareness on mosquito borne diseases among urban & rural population in Northern Gujarat

It is of interest to examine the awareness and precautions of urban and rural residents on a number of mosquito-borne diseases (MBD). A sample of 300 adult people (Rural 150+Urban 150) was selected from Mahesana district of North Gujarat. Majority of samples (47.3 %) had average, 16% poor and 36.7% had good level of awareness in urban areas. In rural areas majority of the samples (40.67%) had average, 28%poor and 31.33% had good level of awareness. (67.3%) urban population were using mosquito repellent liquids and creams and (68.6%) of rural population were using mosquito net. Data shows that both urban and rural populations have moderate awareness on Mosquito Borne Diseases and majority is taking precaution towards these conditions. Data also revealed that there is no significant difference between urban & rural population's precaution measures against Mosquito borne diseases.

Effect of cotton dust on lungs among female workers in cotton industry in northern Gujarat, India

Byssinosis is a disabling occupational lung disease caused by cotton dust. It is a well-known occupational respiratory disease in cotton industry workers caused by cotton dust pollution. Many studies have been documented the effects of cotton dust on pulmonary function among workers employed in cotton-spinning mills. However, little data exist on the prevalence of this disorder in female workers particularly in western part of India. The present study was conducted to analyze the effects of exposure to cotton dust on pulmonary functions among female workers. The study was designed to assess the effects of exposure to cotton dust on lung functions among female cotton industry workers. Study group comprises 50 Female workers of cotton industry and control group comprises 50 age matched females who were neither worked in cotton industry nor exposed to cotton dust. Information was collected using standardized questionnaires, physical examination and spirometric measurements. Student's T test was used to find the difference between spirometric parameters. All the respiratory parameters (FVC, FEV1, FEV1/FVC ratio, FEF 25-75 % PEFR and MVV) were reduced in cotton industry workers as compared with control subjects (p<0.0001) and no significant difference of SpO2 between groups. Cotton dust exposure makes huge impact on respiratory parameters of the cotton industry workers. This deterioration in respiratory health deteriorates with increasing duration of exposure. The health hazards caused by cotton dust should be controlled by creating awareness among the workers & employers.

Gene polymorphism among hypertensive patients with coronary artery disease

The obstruction of the coronary arteries causes Coronary Artery Disease (CAD). It has been reported that interleukin-6 gene is related to the development of cardiovascular diseases such as atherosclerosis and coronary artery disease. This was due to the large variability and short half-life of interleukin 6 (IL-6). There are few studies on the link between interleukin 6 and CAD on the patients with hypertension. Therefore, goal of this study was to see if there is a link between IL-6 gene polymorphisms and coronary artery disease with hypertension patients. The polymorphisms were carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The data was determined for statistical significance using chi-square analysis. A significant difference was found in the GG genotype of IL-6 -174, which was more frequent in cases of CAD (48.67 %) than in controls (8%) and 95% CI was 0.473455 - 0.500326; P<0.010620511. The GG genotype of IL-6-572C/G polymorphism was more frequent in cases of CAD (42.6%) compared with controls (8%) and 95% CI 0.386724 - 0.480945; P<0.017939631). likewise, significant association of variant allele G with CAD patients was reported. Hypertension was significantly higher among patients as compared to controls (P<0.022847535). Our findings indicated that both gene polymorphisms may be associated with development of CAD.

Cardiac remodeling as a consequence and cause of progressive heart failure

Natural history studies in heart failure have shown that increases in left ventricular (LV) volume and LV mass are directly related to future deterioration in LV performance and a less favorable clinical course. Despite the recognized importance of remodeling in heart failure, very little is known about the basic mechanisms that lead to cardiac remodeling. In this review, we will summarize recent clinical and experimental studies that highlight the importance of the remodeling process during the progression of heart failure. The intent of this review is to provide an integrated view of the mechanisms that contribute to LV remodeling at the cellular level, the myocardial level, and the level of the chamber.

Myocardial cytokine gene expression is higher in aortic stenosis than in idiopathic dilated cardiomyopathy

OBJECTIVE

To investigate cytokine gene expression in patients with aortic valve stenosis (AS) and with idiopathic dilated cardiomyopathy (DCM), and to correlate wall stress with myocardial proinflammatory cytokine gene expression.

METHODS

Human left ventricular (LV) myocardial biopsies were obtained for subsequent reverse transcription polymerase chain reaction of tumour necrosis factor alpha (TNFalpha), interleukin (IL)-1beta, and IL-6 mRNA. The study population consisted of 24 patients with AS and 10 patients with idiopathic DCM.

RESULTS

Patients with AS had a larger ejection fraction (56 (5) v 37 (4)%, p < 0.01), smaller LV end diastolic volumes (146 (11) v 267 (21) ml, p < 0.01), and lower end systolic wall stress (44 (7) v 112 (11) kdyn/cm2, p < 0.001). Upregulation of TNFalpha, IL-1beta, and IL-6 gene expression was detected in both groups. However, TNFalpha gene expression was significantly higher in AS than in DCM (p = 0.009). No correlation was found between haemodynamic parameters and TNFalpha gene expression. In patients with AS there was a strong inverse relation between circulating TNFalpha and TNFalpha gene expression (r = -0.685, p = 0.014), between circulating TNFalpha and IL-1beta gene expression (r = -0.664, p = 0.018), and between soluble TNF receptor 2 and TNFalpha gene expression (r = -0.685, p = 0.020). Myocardial gene expression of TNFalpha was significantly higher in patients with well compensated AS than in patients with decompensated AS (p = 0.017). Similarly, patients with decompensated DCM were characterised by significantly lower TNFalpha gene expression than were patients with well compensated DCM (p = 0.011).

CONCLUSION

TNFalpha gene expression is significantly higher in patients with pressure overload than in normal hearts, in patients with idiopathic DCM, and in patients with compensated versus decompensated heart failure. Secondly, in patients with AS proinflammatory cytokine gene expression did not affect systolic performance. The higher TNFalpha gene expression in patients with compensated heart failure suggests that cytokine gene expression has an adaptive role in the early phase of LV remodelling.

Differential regulation of mitogen-activated protein kinases in the failing human heart in response to mechanical unloading

Background- Mechanical unloading of the heart with a left ventricular assist device (LVAD) leads to favorable changes in the biology of the failing cardiac myocyte. To determine a potential mechanism for these improvements, we examined the regulation of mitogen-activated protein kinases (MAPKs) in the failing heart in the presence and absence of LVAD support. Methods and Results- We examined the degree of activation (ie, phosphorylation) of p44/42 extracellularly regulated kinase, p38 kinase, and c-Jun N-terminal kinase (JNK1/2), and the corresponding activity levels of these MAPKs in myocardial samples obtained from 11 patients with LVAD support and in 11 patients without LVAD support. MAPK activity was also examined in an additional 6 patients from whom paired samples were obtained before and after LVAD support. The activity of p44/42 and JNK1/2 were reduced significantly, whereas p38 activity levels were significantly increased after LVAD support. We examined functional parameters that are linked to MAPK activation, namely cardiac myocyte hypertrophy and apoptosis. Both cardiac myocyte cell size and the incidence of cardiac myocyte apoptosis were significantly reduced after LVAD support. Conclusions- Mechanical unloading of the failing heart leads to differential regulation of MAPKs. These changes in MAPK activity are associated with changes in myocyte hypertrophy and viability, suggesting a potential mechanistic basis for some of the observed salutary changes after LVAD support.

Left ventricular remodeling in transgenic mice with cardiac restricted overexpression of tumor necrosis factor

BACKGROUND

The mechanisms responsible for tumor necrosis factor (TNF)-induced LV structural remodeling in the adult heart are not known.

METHODS AND RESULTS

We generated a line of transgenic mice (MHCsTNF) with cardiac restricted overexpression of TNF that develop progressive LV dilation/remodeling from 4 to 12 weeks of age. During the early phases of LV structural remodeling, there was a significant increase in total matrix metalloproteinase (MMP) activity that corresponded to a decrease in total myocardial fibrillar collagen content. As the MHCsTNF mice aged, there was a significant decrease in total MMP zymographic activity that was accompanied by an increase in total fibrillar collagen content. The changes in total MMP activity and myocardial fibrillar collagen content were related to a time- dependent increase in myocardial tissue inhibitor of metalloproteinases (TIMP)-1 levels, resulting in a significant time-dependent decrease in the MMP activity/TIMP level ratio in the MHCsTNF mice. To determine a possible mechanism for the increase in myocardial fibrosis, we also measured levels of TGF-beta(1) and TGF-beta(2) protein levels, which were shown to be significantly elevated in the hearts of the MHCsTNF mice.

CONCLUSIONS

Our results suggest that progressive time-dependent changes in the balance between MMP activity and TIMP activity are responsible, at least in part, for the spectrum of TNF-induced changes in the myofibrillar collagen content that occur during LV structural remodeling in the MHCsTNF mice.

Homocysteine induces expression and secretion of monocyte chemoattractant protein-1 and interleukin-8 in human aortic endothelial cells: implications for vascular disease

BACKGROUND

Proinflammatory cytokines play key roles in atherogenesis and disease progression. Because hyperhomocysteinemia is an independent risk factor for cardiovascular disease, we hypothesized that homocysteine could be atherogenic by altering the expression of specific cytokines in vascular endothelial cells.

METHODS AND RESULTS

Northern blot and RNase protection assays showed that DL-homocysteine induced mRNA expression of the proinflammatory cytokines monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) in cultured human aortic endothelial cells (HAECs). Homocysteine had no effect on expression of other cytokines, namely tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, interleukin-1beta, and transforming growth factor-beta. MCP-1 mRNA expression increased 1 hour after homocysteine treatment, reached a maximum within 2 to 4 hours, and declined to basal levels over the next 24 hours. Induction of mRNA expression for both chemokines was observed with as little as 10 micromol/L DL-homocysteine, and maximal expression was achieved with 50 micromol/L DL-homocysteine. Homocysteine also triggered the release of MCP-1 and IL-8 protein from HAECs into the culture medium. The induction was specific for homocysteine, because equimolar concentrations of L-homocystine, L-cysteine, and L-methionine had no effect on mRNA levels and protein release. Furthermore, L-homocysteine induced chemokine expression, but D-homocysteine did not, thus demonstrating enantiomeric specificity. The culture medium from homocysteine-treated HAECs promoted chemotaxis in human peripheral blood monocytes and U937 cells. Anti-human recombinant MCP-1 antibody blocked the migration.

CONCLUSIONS

Pathophysiological levels of L-homocysteine alter endothelial cell function by upregulating MCP-1 and IL-8 expression and secretion. This suggests that L-homocysteine may contribute to the initiation and progression of vascular disease by promoting leukocyte recruitment.

In vivo expression of proinflammatory mediators in the adult heart after endotoxin administration: the role of toll-like receptor-4

Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and nitric oxide (NO) may play a role in lipopolysaccharide (LPS)-induced cardiac depression. Toll-like receptor-4 (TLR-4) mediates the cytokine response to LPS in immune cells. TLR-4 also is expressed in human and murine myocardial tissue. Therefore, the hypothesis that LPS induces proinflammatory cytokines in the heart via TLR-4 was tested. C3H/HeJ (TLR-4 deficient) and C3HeB/FeJ mice were studied. LPS induced a robust increase in myocardial TNF-alpha and IL-1beta mRNA in C3HeB/FeJ mice. The response in C3H/HeJ mice was blunted and delayed. Myocardial TNF-alpha and IL-1beta protein levels were higher in C3HeB/FeJ mice, as were inducible NO synthase protein and NO production. Activation of myocardial NF-kappaB was observed within 30 min in C3HeB/FeJ mice but not in C3H/HeJ mice. These findings suggest that myocardial TLR-4 is involved in signaling cytokine production within the heart during endotoxic shock.

Functional significance of hemodynamic overload-induced expression of leukemia-inhibitory factor in the adult mammalian heart

BACKGROUND

Leukemia-inhibitory factor (LIF) is a member of the interleukin-6 family of cytokines that utilize gp130 as a common signaling component. In the present study, we examined the mechanisms that govern LIF expression and functional effects in the adult heart.

METHODS AND RESULTS

LIF mRNA and protein biosynthesis were examined in the adult feline heart after hemodynamic overloading ex vivo. Both LIF mRNA and protein expression were detected within 60 to 90 minutes after hemodynamic overloading. Studies in isolated adult cardiac myocytes showed that these cells synthesized both LIF mRNA and protein. The functional effects of LIF in the heart were demonstrated by studies that showed that LIF stimulation led to a significant increase in general protein synthesis and an increase in sarcomeric protein synthesis. Pretreatment with LIF also protected the cells against hypoxia/reoxygenation-induced cardiac myocyte apoptosis and cellular injury. Finally, LIF had no effect on isolated cardiac myocyte cell motion.

CONCLUSIONS

Hemodynamic overload is a sufficient stimulus for LIF expression in the adult mammalian heart. Given that LIF confers both hypertrophic and cytoprotective responses in adult cardiac myocytes, this study suggests that the expression of LIF within the heart may play an important role in mediating homeostatic responses within the myocardium.

Cardiac-specific overexpression of tumor necrosis factor-alpha causes oxidative stress and contractile dysfunction in mouse diaphragm

BACKGROUND

We have developed a transgenic mouse with cardiac-restricted overexpression of tumor necrosis factor-alpha (TNF-alpha). These mice develop a heart failure phenotype characterized by left ventricular dysfunction and remodeling, pulmonary edema, and elevated levels of TNF-alpha in the peripheral circulation from cardiac spillover. Given that TNF-alpha causes atrophy and loss of function in respiratory muscle, we asked whether transgenic mice developed diaphragm dysfunction and whether contractile losses were caused by oxidative stress or tissue remodeling.

METHODS AND RESULTS

muscles excised from transgenic mice and littermate controls were studied in vitro with direct electrical stimulation. Cytosolic oxidant levels were measured with 2', 7'-dichlorofluorescin diacetate; emissions of the oxidized product were detected by fluorescence microscopy. Force generation by the diaphragm of transgenic animals was 47% less than control (13.2+/-0. 8 [+/-SEM] versus 25.1+/-0.6 N/cm(2); P:<0.001); this weakness was associated with greater intracellular oxidant levels (P:<0.025) and was partially reversed by 30-minute incubation with the antioxidant N:-acetylcysteine 10 mmol/L (P:<0.01). Exogenous TNF-alpha 500 micromol/L increased oxidant production in diaphragm of wild-type mice and caused weakness that was inhibited by N:-acetylcysteine, suggesting that changes observed in the diaphragm of transgenic animals were mediated by TNF-alpha. There were no differences in body or diaphragm weights between transgenic and control animals, nor was there evidence of muscle injury or apoptosis.

CONCLUSIONS

Elevated circulating levels of TNF-alpha provoke contractile dysfunction in the diaphragm through an endocrine mechanism thought to be mediated by oxidative stress.

Nitric oxide provokes tumor necrosis factor-alpha expression in adult feline myocardium through a cGMP-dependent pathway

BACKGROUND

The mechanism(s) responsible for the persistent coexpression of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) in the failing heart is unknown.

METHODS AND RESULTS

To determine whether NO was sufficient to provoke TNF-alpha biosynthesis, we examined the effects of an NO donor, S-nitroso-N-acetyl penicillamine (SNAP), in buffer-perfused Langendorff hearts. SNAP (1 micromol/L) treatment resulted in a time- and dose-dependent increase in myocardial TNF-alpha mRNA and protein biosynthesis in adult cat hearts. The effects of SNAP were completely abrogated by a NO quenching agent, 2-(4-carboxyphenyl)-4, 4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (C-PTIO), and mimicked by sodium nitroprusside. Electrophoretic mobility shift assays demonstrated that SNAP treatment led to the rapid induction of nuclear factor kappa-beta (NF-kappaB) but not AP-1. The importance of the cGMP pathway in terms of mediating NO-induced TNF-alpha biosynthesis was shown by studies that demonstrated that 8-bromo-cGMP mimicked the effects of SNAP and that the effects of SNAP could be completely abrogated using a cGMP antagonist, 1H-(1,2, 4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), or protein kinase G antagonist (Rp-8-Br-cGMPS). SNAP and 8-Br-cGMP were both sufficient to lead to the site-specific phosphorylation (serine 32) and degradation of IkappaBalpha in isolated cardiac myocytes. Finally, protein kinase G was sufficient to directly phosphorylate IkappaBalpha on serine 32, a critical step in the activation of NF-kappaB.

CONCLUSIONS

These studies show that NO provokes TNF-alpha biosynthesis through a cGMP-dependent pathway, which suggests that the coincident expression of TNF-alpha and NO may foster self-sustaining positive autocrine/paracrine feedback inflammatory circuits within the failing heart.

Group B Streptococcus induces TNF-alpha gene expression and activation of the transcription factors NF-kappa B and activator protein-1 in human cord blood monocytes

It has been postulated that production of TNF-alpha is central to the pathogenesis of septic shock induced by group B Streptococcus (GBS). In vitro studies using human cord blood monocytes have demonstrated that GBS induces TNF-alpha secretion, but little is known about the intracellular signaling pathways of TNF-alpha induction. In this report we show that heat-killed serotype III GBS induces host cell signal transduction pathways that lead to activation of the transcription factors NF-kappaB and AP-1. Using adenoviral transfer of IkappaBalpha (IkappaBalpha overexpression), the production of TNF-alpha induced by whole GBS was inhibited by only 20%. We also show that the p38 mitogen-activated protein kinase (MAPK) pathway is involved in GBS-induced TNF-alpha secretion, because TNF-alpha protein and mRNA levels in the presence of a specific inhibitor of p38 MAPK, SB 202190, were dramatically diminished. EMSAs showed that SB 202190 inhibited GBS-induced AP-1 activation, but had no effect on NF-kappaB-DNA binding activity. These results indicate that both NF-kappaB and AP-1 (via p38 MAPK) are involved in the regulation of TNF-alpha production in GBS-stimulated neonatal monocytes. Therefore, disrupting the signal transduction pathways induced by GBS has the potential to attenuate the production of immune response mediators, thereby halting or possibly reversing the course of this potentially fatal disease.

Endogenous tumor necrosis factor protects the adult cardiac myocyte against ischemic-induced apoptosis in a murine model of acute myocardial infarction

Previous studies have shown that proinflammatory cytokines, such as tumor necrosis factor (TNF), are expressed after acute hemodynamic overloading and myocardial ischemia/infarction. To define the role of TNF in the setting of ischemia/infarction, we performed a series of acute coronary artery occlusions in mice lacking one or both TNF receptors. Left ventricular infarct size was assessed at 24 h after acute coronary occlusion by triphenyltetrazolium chloride (TTC) staining in wild-type (both TNF receptors present) and mice lacking either the type 1 (TNFR1), type 2 (TNFR2), or both TNF receptors (TNFR1/TNFR2). Left ventricular infarct size as assessed by TTC staining was significantly greater (P < 0.005) in the TNFR1/TNFR2-deficient mice (77.2% +/- 15.3%) when compared with either wild-type mice (46.8% +/- 19.4%) or TNFR1-deficient (47.9% +/- 10.6%) or TNFR2-deficient (41.6% +/- 16.5%) mice. Examination of the extent of necrosis in wild-type and TNFR1/TNFR2-deficient mice by anti-myosin Ab staining demonstrated no significant difference between groups; however, the peak frequency and extent of apoptosis were accelerated in the TNFR1/TNFR2-deficient mice when compared with the wild-type mice. The increase in apoptosis in the TNFR1/TNFR2-deficient mice did not appear to be secondary to a selective up-regulation of the Fas ligand/receptor system in these mice. These data suggest that TNF signaling gives rise to one or more cytoprotective signals that prevent and/or delay the development of cardiac myocyte apoptosis after acute ischemic injury.

Cytokines in heart failure: pathogenetic mechanisms and potential treatment

Recent studies have shown that patients with heart failure overexpress a class of biologically active molecules, generically referred to as pro-inflammatory cytokines. This article will review recent clinical and experimental material that suggests that pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6) may play a role in the pathogenesis of congestive heart failure. In addition, we will review recent studies that suggest that antagonizing cytokines may represent a novel target for heart failure therapy.

Expression and purification of the extracellular ligand-binding domain of the atrial natriuretic peptide (ANP) receptor: monovalent binding with ANP induces 2:2 complexes

The receptor for atrial natriuretic peptide (ANP) is a type-I transmembrane protein containing an extracellular ligand-binding domain, a single transmembrane sequence, an intracellular kinase-homologous domain, and a guanylate cyclase (GCase) domain. Binding of ANP to the extracellular domain causes activation of the GCase domain by an as yet unknown mechanism. To facilitate studies of the receptor structure and signaling mechanism, we have expressed the extracellular ANP-binding domain of rat ANP receptor (NPR-ECD) in a water-soluble form. NPR-ECD was purified to homogeneity by ANP-affinity chromatography. SDS-PAGE gave a single 61-kDa band, which coincided with a radioactive band obtained by photoaffinity-labeling with N4alpha-azidobenzoyl-125I-ANP(4-28). Edman degradation gave a single amino-terminal sequence expected for the mature protein. Both trifluoromethanesulfonic acid and peptide-N-glycosidase F treatments yielded a 50-kDa band, indicating N-glycosylation. The molecular mass of 57 725 Da determined by mass spectrometry indicates the carbohydrate content at 16%. NPR-ECD bound ANP with an affinity comparable to that of the full-length receptor. The ligand selectivity of NPR-ECD (in the order ANP > brain natriuretic peptide >> C-type natriuretic peptide) was also similar to that of the full-length receptor. HPLC gel filtration of NPR-ECD gave a peak with an apparent mass of 74 kDa. Preincubation with ANP generated a new 150-kDa peak with a concomitant decrease of the 74-kDa peak. This shift in peak positions was ANP concentration-dependent and was complete at the NPR-ECD-to-ANP molar ratio of 1:1, indicating equimolar binding. The change in the apparent native molecular weight from 74 to 150 kDa suggests that binding causes dimerization of the NPR-ECD:ANP complex to yield an [NPR-ECD:ANP]2 complex.

The role of cytokines in the failing human heart

Despite repeated attempts to develop a unifying hypothesis that explains the clinical syndrome of heart failure, no single conceptual paradigm has withstood the test of time. In this regard, recent studies have shown that a class of biologically active molecules, generically referred to as cytokines, are overexposed in heart failure. This article will review recent clinical and experimental material that suggest proinflammatory (stress activated) cytokines such as tumor necrosis factor-alpha (TFN-alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6) may play a role in the pathogenesis of congestive heart failure. The scope of this article includes an overview of the biology of cytokines in the heart, as well as review of the clinical studies that have documented elevated levels of cytokines and cytokine receptors in patients with heart failure.

Cardiac myotrophin exhibits rel/NF-kappa B interacting activity in vitro

Myotrophin is a soluble-12 kilodalton protein isolated from hypertrophied spontaneously hypertensive rat and dilated cardiomyopathic human hearts. We have recently cloned the gene coding for myotrophin and expressed it in Escherichia coli. In the present study, the expression of myotrophin gene was analyzed, and at least seven transcripts have been detected in rat heart and in other tissues. We have further analyzed the primary structure of myotrophin protein and identified significant new structural and functional domains. Our analysis revealed that one of the ankyrin repeats of myotrophin is highly homologous specifically to those of myotrophin is highly homologous specifically to those of I kappa B alpha/rel ankyrin repeats. In addition, putative consensus phosphorylation sites for protein kinase C and casein kinase II, which were observed in I kappa B alpha proteins, were identified in myotrophin. To verify the significance of these homologies, kappa B gel shift assays were performed with Jurkat T cell nuclear extract proteins and the recombinant myotrophin. Results of these assays indicate that the recombinant myotrophin has the ability to interact with NF-kappa B/rel proteins as revealed by the formation of ternary protein-DNA complexes. While myotrophin-specific antibodies inhibited the formation of these complexes, rel-specific p50 and p65 antibodies supershifted these complexes. Thus, these results clearly indicate that the myotrophin protein to be a unique rel/NF-kappa B interacting protein.

Interaction site of GTP binding Gh (transglutaminase II) with phospholipase C

The GTP binding G alpha h (transglutaminase II) mediates the alpha 1B-adrenoreceptor signal to a 69-kDa phospholipase C (PLC). Thus, G alpha h possesses both GTPase and transglutaminase activities with a signal transfer role. The recognition sites of this unique GTP binding protein for either the receptor or the effector are completely unknown. A site on human heart G alpha h (hhG alpha h) has been identified that interacts with and stimulates PLC. Expressed mutants of hhG alpha h with deleted C-terminal regions lost the response to (-)-epinephrine and GTP and failed to coimmunoprecipitate PLC by the specific Gh7 alpha antibody. The interaction regions were further defined by studies with synthetic peptides of hhG alpha h and a chimera in which residues Val665-Lys672 of hhG alpha h were substituted with Ile707-Ser714 residues of human coagulation factor XIIIa. Thus, eight amino acid residues near the C terminus of hhG alpha h are critical for recognition and stimulation of PLC.

The 1629-bp open reading frame of the Autographa californica multinucleocapsid nuclear polyhedrosis virus encodes a virion structural protein

A 1629-bp open reading frame (ORF) of Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) is shown to encode a 78-kDa virion structural protein. To determine this, polyclonal antibody was made to a fusion protein synthesized in Escherichia coli from a chimeric gene that contained 1415 bp of the 1629-bp gene. In Western blot analyses, this antibody cross-reacted with a protein of about 78 kDa in both extracellular virions (ECV) and virions isolated from polyhedra (PDV), and with a 78-kDa protein in PDV envelope preparations, but not with PDV nucleocapsids. This suggests that the protein encoded by the 1629-bp ORF is a virion envelope protein or a protein that occurs in the virion intermediate layer between the envelope and nucleocapsid.

Sequence and in vitro translational analysis of a 1629-nucleotide ORF in Autographa californica nuclear polyhedrosis virus strain E2

The complete nucleotide (nt) sequence of an open reading frame (ORF) (map unit 5.1 to 3.8) from Autographa californica nuclear polyhedrosis virus strain E2 (AcMNPV-E2) has been determined. This 1629-nt ORF has a coding potential for a 61-kDa Pro-rich protein. However, in vitro translation of the 1629-nt ORF and sodium dodecyl sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) revealed a 78-kDa protein product. The discrepancy between the M(r) predicted by the nt sequence and that obtained from the in vitro translational analysis is due to the high Pro content of this protein. The high Pro content causes anomalous migration of this protein during SDS-PAGE.

In vivo transcriptional analysis of three baculovirus genes: evidence of homology between viral and host transcripts

Transcripts for the gp64 and polyhedrin genes as well as a 1629 open reading frame (1629 ORF) of the Autographa californica nuclear polyhedrosis virus were examined in the midgut tissues and hemocytes of uninfected and infected host Trichoplusia ni larvae and Sf21 cells. Polyhedrin-specific transcripts of 1.2, 3.4, and 4.9 kb were expressed in both infected larval tissues and infected Sf21 cells. The highest level of expression for polyhedrin-specific transcripts was observed in hemocytes, whereas the lowest level occurred in midgut. The expression of the 2.0-kb transcript for the gp64 gene increased continuously through 72 hr postinfection in the infected midgut tissues. This transcript was also observed in infected hemocytes, though its expression declined at 72 hr postinfection, as the expression for polyhedrin-specific transcripts peaked. The 1629 ORF transcripts of 2.0 and 3.2 kb were expressed in both types of infected tissues. More significantly, a 1629-ORF-specific probe detected host transcripts of 0.7 and 2.5 kb in uninfected midgut tissues as well as transcripts of 2.5, 8.8, and 11.0 kb in uninfected hemocytes under high stringency conditions. The latter results indicate that these host transcripts share homology with the 1629 ORF gene.

Primary structure of the polymerase acidic (PA) gene of an influenza B virus (B/Sing/222/79)

A DNA copy of influenza B/Singapore/222/79 viral RNA segment 3 containing the gene coding for the polymerase acidic (PA) protein has been cloned in Escherichia coli plasmid pBR322, and its nucleotide sequence has been determined. The cDNA clone was incomplete and contained 1810 nucleotides (nt 396 to 2205). The remaining nucleotide sequence at both 5' and 3' ends of B PA gene was obtained by sequencing the viral RNA (minus sense) and messenger RNA (plus sense) using oligonucleotide primers. The influenza B PA gene contains 2304 nucleotides and codes for a protein of 725 amino acids with a molecular weight of 83,000. The predicted influenza B PA protein is less acidic than the influenza A PA protein. Computer alignment of the influenza B PA amino acid sequence with that of influenza A PA (A/PR/8/34) revealed an overall 38% direct homology which increases to 45% in the carboxyl terminus half of the protein. In addition, comparison of the secondary structural elements, hydropathy profile, and isofunctional amino acid changes between B PA and A PA proteins demonstrated a strong structural and possibly functional conservation between these two proteins. These data suggest that PA genes of influenza A and B viruses arose from a common ancestor gene.

Mutational analysis of the signal-anchor domain of influenza virus neuraminidase

Influenza virus neuraminidase (NA; EC 3.2.1.18) possesses a signal-anchor hydrophobic domain at the amino terminus. To characterize the nature of this signal-anchor domain we have introduced single amino acid changes in this domain by oligonucleotide-directed mutagenesis. Three mutant NA proteins that were synthesized contained a single charged amino acid residue in place of a hydrophobic amino acid residue at position 11, 17, or 26 of the signal-anchor domain. When the altered NA proteins were expressed in CV-1 cells, two phenotypes were observed: substitution of arginine in place of glycine at position 11 and substitution of aspartic acid for valine at position 17 did not abolish the signal, the anchor, or the transport functions. On the other hand, substitution of arginine for isoleucine at position 26 blocked the migration of the NA protein from the Golgi complex to the cell surface. Double mutants were constructed from these single point mutations and they exhibited two phenotypes: one double mutant (aspartic acid at position 17 and arginine at position 26) was present mostly in the cytoplasm and the other (arginine at positions 11 and 26) was present mostly in the rough endoplasmic reticulum. These results indicate that the hydrophobic amino acids at positions 11, 17, and 26 are required for intracellular transport. Furthermore, the accumulation of the mutant proteins in the rough endoplasmic reticulum or the Golgi apparatus suggests the existence of putative intracellular transport (or traffic) signals in the signal-anchor domain of NA.

Biological and immunological properties of haemagglutinin and neuraminidase expressed from cloned cDNAs in prokaryotic and eukaryotic cells

To study the biological and immunological properties of influenza virus surface glycoproteins, cDNA copies of the haemagglutinin (HA) and the neuraminidase (NA) genes of A/WSN/33 influenza virus were cloned and expressed in prokaryotic and eukaryotic cells. In Escherichia coli, maximum expression of HA is obtained only as a fusion protein in which the NH2-terminal portion is provided by a bacterial protein (i.e. beta gal or trpLE'). The HA expressed in bacteria (bacterial HA) is recognized by polyclonal anti-WSN antibodies but not by neutralizing monoclonal antibodies. The antibodies made against the bacterial HA bind to the detergent-treated viral HA, intact virus and live influenza infected cells, but fail to show either haemagglutination inhibition (HI) or virus neutralization. These results suggest that the three-dimensional structure as well as the antigenic epitopes of the bacterial HA are different from that of native viral HA. HA, expressed from cDNA in cultured animal cells, is shown to possess the structural features of the native viral HA. It is glycosylated, transported to the apical domain of the plasma membrane of polarized cells, causes haemadsorption and can induce cell to cell fusion at low pH after proteolytic cleavage. An attempt was made to define the structural features of HA required for sorting and directional transport by making chimeras with vesicular stomatitis virus G (VSV G) proteins either by switching the amino terminus or the carboxy terminus of HA with that of VSV G. These chimeric proteins were translocated across the rough endoplasmic reticulum (RER) but were blocked in transport between the RER and cell membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Influenza viral (A/WSN/33) hemagglutinin is expressed and glycosylated in the yeast Saccharomyces cerevisiae

Recombinant plasmids were constructed in which genes coding for either the entire or the signal-minus (amino acid residues 2-17 deleted) hemagglutinin (HA) of WSN influenza virus were placed under the control of the alcohol dehydrogenase I gene promoter of Saccharomyces cerevisiae. Both recombinant plasmids were shown to direct the synthesis of HA-specific polypeptides that were detected by immunoprecipitation with antiviral antibodies. The complete HA produced in yeast had an approximate Mr of 70,000 and was glycosylated, as determined by the endoglycosidase H sensitivity, and was bound to membrane. Therefore, the complete HA polypeptide possessing the signal sequence probably traversed the yeast secretory pathways. Signal-minus HA, on the other hand, had a lower molecular weight and was nonglycosylated. The specific binding of yeast HA with antiviral antibodies could be competitively inhibited by influenza viral HA, demonstrating that the HA produced in yeast contained antigenic determinants of the native viral HA.

Defective interfering influenza RNAs of polymerase 3 gene contain single as well as multiple internal deletions

Defective interfering (DI) RNAs of influenza virus arise from polymerase genes by internal deletions. Utilizing the recombinant DNA cloning and sequencing techniques we have determined the nucleotide sequence of two DI RNAs of L clone of A/WSN/33 (L2a-7 and L2a-17) which are of polymerase 3 origin. L2a-7 DI RNA is 659 nucleotides long and contains a single internal deletion of 1682 nucleotides (nucleotide position 273 to 1954) of P3 gene. L2a-17 DI RNA (611 nucleotides long), on the other hand, contains two internal deletions: one of 1682 nucleotides at the identical position as that in L2a-7, the other 48 nucleotides at the nucleotide position 2032 to 2079 of P3 gene. Except for a few base mismatches the sequence of DI RNAs are identical to the corresponding portion of the P3 gene including the 5' and the 3' termini. Since these two DI RNAs contain one identical deletion but differ in the other deletion as well as in base mismatches, these two DI RNAs appear to originate from a progenitor DI RNA rather than independently from the progenitor P3 gene. The sequences around the deletion point do not reflect a consensus sequence for the origin of these deletions and suggest the role of multiple mechanisms in the generation and evolution of influenza DI RNAs.

Sequence analysis of the polymerase 1 gene and the secondary structure prediction of polymerase 1 protein of human influenza virus A/WSN/33

The nucleotide sequence of polymerase 1 (P1) gene of a human influenza virus (A/WSN/33) has been determined by using cDNA clones, except for the last 83 nucleotides, which were obtained by primer extension. The WSN P1 gene contains 2,341 nucleotides and codes for a protein of 757 amino acids (Mr = 86,500). P1 gene possesses a striking tandem repeat of 12 nucleotides (nucleotide position 2,188 to 2,199, 2,200 to 2,211) and a corresponding tandem repeat of tetrapeptide in the P1 protein. The deduced sequence of P1 protein is enriched in basic amino acids, particularly arginine. In addition, it also contains clusters of basic amino acids which may provide sites for the interaction with the template virion RNA capped primer as well as with other proteins involved in viral replication and transcription. A secondary structure prediction, using Chou and Fasman analyses (Annu. Rev. Biochem. 47:251-276, 1978), shows that the P1 protein possesses some unique features, viz., one "four-helical supersecondary structure" and four "polypeptide double helices" (antiparallel beta-pleated sheets) which are considered important in RNA binding.

Complete sequence analyses show that two defective interfering influenza viral RNAs contain a single internal deletion of a polymerase gene

Defective interfering (DI) influenza viral RNAs arise by internal deletion of progenitor RNAs. By using recombinant DNA cloning and DNA sequence analysis techniques, we have deduced the complete sequence of two such RNAs (L2b and L3), both arising from the same polymerase (P1) gene of WSN influenza virus. We have also partially determined the sequence of the P1 polymerase gene, including the sequence at the point of deletion and the flanking regions. Our sequence study shows the following. (i) Both L2b and L3 arise by a simple deletion in the P1 gene. (ii) L2b and L3 are 683 and 441 nucleotides long, respectively. (iii) The first 413 and 244 nucleotides of the 5' ends of L2b and L3, respectively, are identical to those of the 5' end of the P1 gene. (iv) The last 270 nucleotides of L2b and 197 nucleotides of L3 are the same as those of the 3' end of the P1 gene. (v) The entire sequence of L3 is present in the sequence of L2b. (vi) Both the 5' and the 3' termini, including the transcription stop and poly(A) addition signals of the progenitor P1 gene, are present in both L2b and L3. (vii) The sequences at the deletion point and the flanking region of the P1 gene do not resemble the consensus splicing sequence of spliced mRNA suggesting that a replicational event rather than splicing is involved in the formation of influenza defective interfering RNAs.

Mapping of two transcription mutations (tlnI and tlnII) conferring thiolutin resistance, adjacent to dnaZ and rho in Escherichia coli

Two mutations in Escherichia coli conferring resistance to the transcription initiation inhibitor, thiolutin, have been mapped. One of these mutations (tln-I)( maps at 10.2 min on the genetic map and is cotransducible with dnaZ at a frequency of approximately 50%. The other mutation (tln-II) maps between metE and ilvD, probably close to rho, and is cotransducible with ilvD at a frequency of approximately 65%. The presence of both the mutations in the same cell confers resistance to thiolutin in minimal medium. Either one of them alone renders the cell 'conditionally auxotrophic' in the presence of the drug. The implications of these findings are discussed in relation to the mode of action of the thiolutin sensitive factors in transcription.

Thiolutin resistant mutants of Escherichia coli are they RNA chain initiation mutants?

Four mutants of Escherichia coli KL16 resistant to the antibiotic Thiolutin have been isolated. This drug was earlier reported to be an inhibitor of RNA chain elongation. The first mutant, TLrI, is resistant only in rich or partially rich media: it can, however, grow in minimal medium containing the drug with a very long doubling time. The other mutants TLrII, TLrIIIa and TLrIIIb are resistant in rich as well as minimal media. beta-galactosidase could not be induced in TLrI and TLrII in the presence of thiolutin whereas the enzyme is constitutively synthesised in TLrIIIa and TLrIIIb irrespective of the drug. The mutants do not support the development of phage T4 in presence of the drug, if the drug is added along with the phage, but "escape" the inhibition if phage development is allowed to proceed for some time before the addition of the drug. The time of this escape is characteristic of the mutant. Even in a sensitive strain, T7 growth escapes inhibition very soon after infection, around the time the phage-specific RNA polymerase is synthesized. In the parent strain the kinetics of inhibition of beta-galactosidase induction resembles more the inhibition caused by rifampicin than by streptolydigin. It is proposed that thiolutin could be an inhibitor of RNA chain initiation and resistance might be due to mutation in the subunit(s)/factor(s) involved in initiation.