Assessment of Adolescents' Overweight and Obesity Risk Factors Among Alabnaa Schools in Tabuk City, Saudi Arabia.

BACKGROUND: The prevalence of overweight and obesity among adolescents in Saudi Arabia has been progressively increasing. Obesity is associated with an increased risk of various morbidities and mortality. Identifying the factors that contribute to obesity in this age group is crucial for implementing targeted prevention measures. AIM: The aim of this study was to identify risk factors for overweight and obesity among adolescents aged nine to 17 years residing in Tabuk City, Saudi Arabia. METHODS: A case-control study was conducted during the 2021-2022 academic year at Alabnaa Schools in Tabuk City, Saudi Arabia. The study included overweight/obese individuals (cases, n = 125) and normal-weight individuals (controls, n = 201) who were selected based on their body mass index and classified according to the World Health Organization's reference for defining overweight and obesity in individuals aged five to 19 years. Data were collected from both groups using a self-administered questionnaire. RESULTS: The study analyzed 125 overweight/obese students and 201 normal-weight students who were matched for sex and age (p > 0.05). Logistic regression analysis identified several risk factors for overweight or obesity among adolescents. A family history of obesity was found to be associated with a 5.735 times increased likelihood of obesity (95% CI: 3.318-9.912, p < 0.001). Another significant contributing risk factor for obesity was frequent consumption of four or more meals per day (adjusted odds ratio: 3.091, 95% CI: 1.094-8.736, p = 0.033). Students who used electronic devices for more than five hours were 2.422 times more likely to exhibit obesity (p = 0.006). CONCLUSIONS: Certain factors may increase the risk of overweight or obesity in adolescents aged nine to 17 years. These factors include frequent eating, prolonged use of electronic devices, family history of obesity, and the misconception that obesity is not an illness. Tailored school health programs are needed to improve students' healthy lifestyles and eating behaviors, minimize sedentary entertainment and use of electronic devices, and engage children in physical activity.

Ion-imprinted aminoguanidine-chitosan for selective recognition of lanthanum (III) from wastewater.

Developing a sorbent for the removal of La3+ ions from wastewater offers significant environmental and economic advantages. This study employed an ion-imprinting process to integrate La3+ ions into a newly developed derivative of aminoguanidine-chitosan (AGCS), synthesized via an innovative method. The process initiated with the modification of chitosan by attaching cyanoacetyl groups through amide bonds, yielding cyanoacetyl chitosan (CAC). This derivative underwent further modification with aminoguanidine to produce the chelating AGCS biopolymer. The binding of La3+ ions to AGCS occurred through imprinting and cross-linking with epichlorohydrin (ECH), followed by the extraction of La3+, resulting in the La3+ ion-imprinted sorbent (La-AGCS). Structural confirmation of these chitosan derivatives was established through elemental analysis, FTIR, and NMR. SEM analysis revealed that La-AGCS exhibited a more porous structure compared to the smoother non-imprinted polymer (NIP). La-AGCS demonstrated superior La3+ capture capability, with a maximum capacity of 286 ± 1 mg/g. The adsorption process, fitting the Langmuir and pseudo-second-order models, indicated a primary chemisorption mechanism. Moreover, La-AGCS displayed excellent selectivity for La3+, exhibiting selectivity coefficients ranging from 4 to 13 against other metals. This study underscores a strategic approach in designing advanced materials tailored for La3+ removal, capitalizing on specific chelator properties and ion-imprinting technology.

Awareness and Practice of Patients with Helicobacter pylori Infection Toward their Disease in the Riyadh Region, Saudi Arabia.

Objective: This study aimed to study the awareness and practice of patients with Helicobacter pylori (H. pylori) toward their disease in the Riyadh region, Saudi Arabia. Material and Methods: This is a descriptive cross-sectional community-based study, in the central region of the kingdom. The target population of this study was adult patients with H. pylori infection, and a sample of 808 Saudi and non-Saudi male and female individuals were randomly selected using an online questionnaire. A consent form was obtained from all participants. Ethical approval was obtained from the university ethics committee. Results: There were a total of 808 responses. Most participants were female (89.4%) (n = 722) and between the ages of 35 and 60 years (60.8%), and most participants had a bachelor's degree (62.4%). 53.47% of the participants have good knowledge regarding their disease. Most of the participants knew it could cause gastric and duodenal ulcers (82.5%), but they did not know the infection might cause gastric cancer (48.6%). Conclusion: The study concluded that the majority of patients with H. pylori infection (53.47%) have good knowledge regarding their disease. Additionally, many participants were aware of the symptoms associated with H. pylori. Furthermore, many participants complained about their treatment.

Production of Hybrid Nanocomposites Based on Iron Waste Reinforced with Niobium Carbide/Granite Nanoparticles with Outstanding Strength and Wear Resistance for Use in Industrial Applications.

The main objective of this work is to recycle unwanted industrial waste in order to produce innovative nanocomposites with improved mechanical, tribological, and thermal properties for use in various industrial purposes. In this context, powder metallurgy (PM) technique was used to fabricate iron (Fe)/copper (Cu)/niobium carbide (NbC)/granite nanocomposites having outstanding mechanical, wear and thermal properties. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) examinations were used to investigate the particle size, crystal size, and phase composition of the milled samples. Additionally, it was investigated how different volume percentages of the NbC and granite affected the sintered specimens in terms of density, microstructure, mechanical and wear properties, and coefficient of thermal expansion (CTE). According to the findings, the milled powders included particles that were around 55 nm in size and clearly contained agglomerates. The results showed that the addition of 4 vol.% NbC and 8 vol.% granite nanoparticles caused a reduction in the Fe-Cu alloy matrix particle sizes up to 47.8 nm and served as a barrier to the migration of dislocations. In addition, the successive increase in the hybrid concentrations led to a significant decrease in the crystal size of the samples prepared as follows: 29.73, 27.58, 22.69, 19.95 and 15.8 nm. Furthermore, compared with the base Fe-Cu alloy, the nanocomposite having 12 vol.% of hybrid reinforcement demonstrated a significant improvement in the microhardness, ultimate strength, Young's modulus, longitudinal modulus, shear modulus, bulk modulus, CTE and wear rate by 94.3, 96.4, 61.1, 78.2, 57.1, 73.6, 25.6 and 61.9%, respectively. This indicates that both NbC and granite can actually act as excellent reinforcements in the Fe alloy.

Managing patients' pain in the intensive care units: Nurses' awareness of pain management.

OBJECTIVES: To assess nurses' knowledge and attitudes toward pain management in intensive care units (ICUs) in Saudi Arabia. METHODS: A cross-sectional correlational study was carried out at 5 governmental hospitals in the Al-Qassim region (namely, Buraydah Centeral Hospital, King Fahad Spcialist Hospital, Al Rass General Hospital, Bukariyah General Hospital, and Al Badaya General Hospital) using purposive sampling to collect data between May 2020 and July 2020. Nurses' awareness of pain management was assessed using the Nurses' Knowledge and Attitudes Survey Regarding Pain (NKASRP). Statistical Pacaksge for the Social Sciences software was used for data analysis. Descriptive statistics were employed. The Spearman's correlation test was carried out to determine correlations. RESULTS: The mean score for ICUs nurses' pain management awareness was 22.59, suggesting knowledge and behaviors deficits toward pain management. Positive correlations were found between nurses' age, total years of clinical nursing experience, and their total score on pain management awareness. Nurses' gender, religion, education, and years of experience as ICU nurses showed no association with their scores on NKASRP. CONCLUSION: Insufficient pain management knowledge and unacceptable attitudes were established among nurses owing to several barriers and obstacles. Pain assessment and management educational programs should be held regularly for all nurses in the Al-Qassim, Saudi Arabia, especially ICU nurses.

Prevalence and Clinical Characterization of Bocavirus Infection in a Specialized Children's Hospital in Saudi Arabia.

Aim The aim of this study was to assess the prevalence and clinical characterization of bocavirus infection in patients admitted with respiratory symptoms to a specialized children's hospital in Riyadh, Saudi Arabia. Methods This is a retrospective cross-sectional study that included children aged 0-14 years and was conducted over a two-year period (2017-2019). All data were gathered from an electronic information recording system, which included patients' demographics, comorbidities, clinical presentation, complication, and duration of hospitalization. Results Among all patients (11,709) admitted to King Abdullah Specialized Children's Hospital with predominant respiratory symptoms during the study period, 193 (1.6%) patients had bocavirus infections. Most of the patients were diagnosed in winter months. Cough was the primary presenting symptom (91.7%) followed by fever (83.4%). Gastrointestinal symptoms were also common (anorexia in 62% and vomiting in 39%). In 80% (n=154/193) of cases, bocavirus co-existed with other viruses, namely, human rhinovirus (45.8%), human adenovirus (31.2%), and respiratory syncytial virus type A (17.5%). Moreover, those who required oxygen supply stayed longer in the hospital (p<0.001) and were more likely to receive multiple medications such as bronchodilators (p<0.001), corticosteroids (p<0.001), and nebulized racemic epinephrine (p>0.05). Children infected with bocavirus and co-existing viruses were less likely to require oxygen supply (p<0.050). Conclusion Bocavirus infection is more common during winter months and predominantly affects respiratory and gastrointestinal systems in children. More studies are needed to evaluate the global impact of this recently recognized infection.

Methicillin and multidrug resistant pathogenic Staphylococcus aureus associated sepsis in hospitalized neonatal infections and antibiotic susceptibility.

BACKGROUND: Neonatal infection is infection of the newborn or neonate acquired in first four weeks of life or during prenatal development. Microorganism associated neonatal infections caused severe mortality in recent years. It is developed either prenatally or within 28 days of neonatal period. This infection is mainly transmitted from mother to child through placenta. It has been well associated with the premature rupture of membranes which markedly enhances the risk of neonatal sepsis. METHODS: The present experiment was designed to analyze bacteria, their antibiotic resistance pattern and possible risk factors among neonatal patients with sepsis. The neonates specimen was subjected for the isolation of bacteria and antibiotic susceptibility test. Neonates were analyzed with previous clinical history such as, previous admission in hospitals, mode of delivery, birth weight, and feeding type in accordance with questionnaire. RESULTS: Gram-positive bacteria isolates were found to be high (79 strains, 64.22%) than the Gram-negative bacteria (44 strains, 32.5%). Staphylococcus aureus (33 strains, 26.9%) was the major Gram-positive groups of bacteria. Multidrug resistance analysis accounted more S. aureus (26.9%) and 5 strains (15.15%) showed methicillin resistance, whereas 84.9% were found to be sensitive to methicillin. CONCLUSION: In this study, S. aureus and K. pneumoniae were the highest frequency of isolates. The overall percentage of multidrug resistant isolates was high in this study. Highest degree of resistance was observed in ampicillin against all isolates. Hence much attention is required while diagnosing sepsis among neonates. To analyze the risk for neonatal sepsis, it is not preferable for caesarian mode of delivery. Moreover, frequent screening of mother, suitable prenatal care of newborns with proper clinical interventions isthe key elements to control sepsis.

Biofilm producing indigenous bacteria isolated from municipal sludge and their nutrient removal ability in moving bed biofilm reactor from the wastewater.

In the present study, improved moving bed biofilm reactor (MBBR) was applied to enhance the nutrient removal ability of the municipal wastewater. A total of 18 indigenous bacterial isolates were screened from the sewage sludge sample and nitrate reductase, nitrite reductase and hydroxylamine oxidase was analyzed. The strains Pseudomonas aeruginosa NU1 and Acinetobacter calcoaceticus K12 produced 0.87 ± 0.05 U/mg and 0.52 ± 0.12 U/mg hydroxylamine oxidase, 1.023 ± 0.062 U/mg and 1.29 ± 0.07 U/mg nitrite reductase, and 0.789 ± 0.031 U/mg and 1.07 ± 0.13 U/mg nitrate reductase. Nitrogen and phosphate removal improved by the addition of nutrient sources and achieved > 80% removal rate. pH and temperature of the medium also affected nutrient removal and improved removal was achieved at optimum level (p < 0.05). MBBR was designed with R1 (aerobic), R2 and R3 (anoxic) reactors. MBBR reactors removed acceptable level phosphorus removal properties up to 7.2 ± 3.8%, 42.4 ± 4.6%, and 84.2 ± 13.1% in the R1, R2, R3 and R4 reactors, respectively. Denitrification rate showed linear relationship at increasing concentrations nitrogen content in the reactor and denitrification rate was 1.43 g NO2-N /m2/day at 1.5 g NO2-N /m2/day. Dehydrogenase activity was assayed in all reactors and maximum amount was detected in the aerobic biofilm reactor. Based on the present findings, MBBRs and the selected bacterial strains are useful for the degradation domestic wastewater with minimum working area.

Impact of work environment perceptions and communication satisfaction on the intention to quit: an empirical analysis of nurses in Saudi Arabia.

OBJECTIVE: In consideration of the current nursing shortage in Saudi Arabia, we aimed to investigate the association among perceptions of work environment, communication satisfaction, and intentions to quit nursing profession among nurses. In addition, we aimed to investigate the mediating effect of communication satisfaction on the association between nurses' perception of work environment and their intentions to quit nursing profession. METHODS: This predictive correlational study was conducted at one of the major hospitals in Saudi Arabia from January 2020 to March 2020. It included a convenience sample of 367 full-time registered nurses who completed three types of close-ended questionnaires. We used IBM SPSS version 24.0 to analyze the collected data. Regression analyses were used to test the study's hypotheses. All regression assumptions were assessed and confirmed. Significance for all tests was set at p ≤ .05. RESULTS: The findings indicated an affirmative association between work environment perception and communication satisfaction (b = .764, p < .05) among nurses. In addition, findings showed that work environment perception (b = -.187, p < .05) and communication satisfaction (b = -.226, p < .05) have negative impacts on the nurses' intentions to quit; indicating that as work environment perception or communication satisfaction increases, the intention to quit decreases among nurses. Further, a mediation effect of communication satisfaction on the relationship between work environment perception and intention to quit was confirmed. CONCLUSION: This study presents a novel conceptual framework developed based on the literature about the predisposing factors for nurses' intentions to quit nursing profession. Our results suggest that work environment perception and communication satisfaction among the most contributing factors for nurses resignation. Effective communication was established as a crucial factor for establishing attractive and healthy working environment. Nursing managers can benefit by applying these findings to develop appropriate strategies to inhibit the shortage of nurses in Saudi Arabia.

Prevalence of dry eye syndrome in association with the use of contact lenses in Saudi Arabia.

BACKGROUND: Dry eye disease is a tear film disorder which can cause discomfort to patients and negatively affect vision acuity. A number of risk factors has been reported to affect the incidence and severity of dry eye syndrome (DES). The aim is to study the prevalence of DES in Saudi Arabia and the factors affecting the severity of DES in relation to the use of contact lenses. METHODS: A cross-sectional questionnaire-based study was conducted on 310 participants using the ocular surface disease index (OSDI) questionnaire and the eye dryness part from contact lens questionnaire-8 (CLDEQ-8). Dry eye OSDI scores were compared across different epidemiological and risk factors with focus on the use of contact lenses. Pearson and Spearman's correlation coefficients were used to analyze the frequency of contact lenses usage in relation to OSDI scores. Student's t-test and one-way analysis of variance (ANOVA) tests were used to compare means of two or more than two groups, respectively. RESULTS: Forty eight (15.5%) of participants did not have any degree of DES, achieving an OSDI score between 0 and 12. Forty participants (12.9%) scored from 13 to 22, (mild DES), 44 (14.2%) were moderate, scoring 23-32 on the OSDI, while those who scored above 33 were 178 (57.4%) had severe DES. The mean score for all participants was 37.8. A high percentage of participants (84.5%) had some degree of DES. There was a strong positive correlation between OSDI score and the frequency of the feeling of dry eye and a moderate positive correlation between OSDI score and the intensity of dryness feeling. Out of 310 participants, 136 (43.9%) indicated using contact lenses. There was no significant association between the use of contact lenses per se and DES, however, those who used contact lenses more frequently had significantly higher OSDI scores. CONCLUSIONS: Dry eye syndrome is a widespread, underdiagnosed condition in Saudi Arabia. The frequency of contact lenses use may contribute to the incidence of DES.

Effect of Air Pollution on Glutathione S-Transferase Activity and Total Antioxidant Capacity: Cross Sectional Study in Kuwait.

BACKGROUND: Air pollution poses a significant threat to human health worldwide. Investigating potential health impacts is essential to the development of regulations and legislation to minimize health risks. OBJECTIVES: The aim of the present study was to investigate the potentially hazardous effect of air pollution on the Ali Sabah Al Salem residential area in Kuwait by comparing the pollution level to a control area (Al-Qirawan) by assessing two biomarkers: erythrocyte glutathione S-transferases (e-GST) and total blood antioxidant, and then correlating the activity to pollution-related oxidative stress. METHODS: The average concentrations of several airborne gases were measured at Ali Sabah Al Salem and Al-Qirawan, including ozone, carbon monoxide, nitrogen dioxide, nitrogen oxides, particulate matter less than 10 µm (PM10), sulfur dioxide, ammonia, carbon dioxide, hydrogen sulfide, methane, and non-methane hydrocarbon. A total of fifty-eight participants were sampled from two different areas and divided into two groups. The study group was composed of 40 residents exposed to polluted ambient air in the Ali Sabah Al Salem residential area. A reference group composed of 18 residents in the Al-Qairawan area living far from major pollution sources was also tested. RESULTS: All measured gases were higher in concentration at Ali Sabah Al Salem compared to the Al-Qirawan area. Furthermore, PM10 and sulfur dioxide were higher than World Health Organization (WHO) guidelines. The e-GST activity was lower among participants of the Ali Sabah Al Salem residential area compared to participants living in the Al-Qairawan area. The total antioxidant capacity in whole blood of Ali Sabah Al Salem residents was significantly (p<0.0001) higher than in control subjects. CONCLUSIONS: Residents in Ali Sabah Al Salem are exposed to a high level of air pollution that has a serious impact on glutathione S-transferases levels. Subsequently, regulations on pollution sources are needed to lower current health risks. Furthermore, the present study provides evidence that finger-prick blood sampling is a quick, non-invasive method suitable for screening e-GST activity and total antioxidants which may be applied for surveillance purposes. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: The study was approved by the Scientific Research Committee of the Public Authority for Applied Education and Training, Kuwait. COMPETING INTERESTS: The authors declare no competing financial interests.

Educational and Behavioral Models for Promoting Health in Saudi Arabia: A Theoretical Overview.

In recent years, the field of environmental health promotion gained new prominence as awareness of physical environmental stressors and exposures escalated in Saudi Arabia. Although, several theories and conceptual models are routinely used for guiding health education and promotion interventions, they are rarely applied to environmental health issues in Saudi Arabia. This study theoretically reviews the educational and behavioral models for promoting health in Saudi Arabia. This study examines how education and behavioral models can reduce exposure to environmental health risks. In particular, this article describes the application of ecological theory with regard to its theoretical, analytical, and methodological challenges to future research in educational and behavioral studies. The implications of ecological theory are discussed for environmental health promotion. Ecological theory can further demonstrate the dimensions of health behaviors such as procedures for changing them. Health behaviors are also affected by many forces such as physical and social environments. This theory can assist planners in identifying the most appropriate target audiences, methods to improve change, and consequences for assessment. This theory is also important in including social, cultural, and physical factors that affect health consequences, which include factors such as social cohesion, behavioral patterns, emotional wellbeing, genetic heritage, and developmental maturation.

Illness Perception and Medication Adherence Among Patients with Primary Hypothyroidism in Al Qassim, Saudi Arabia.

PURPOSE: Poor adherence to levothyroxine is a potential risk factor for treatment failure that ultimately leads to increased healthcare costs and serious health outcomes. This study aimed to investigate the correlation between illness perception and medication adherence among primary hypothyroidism patients. PATIENTS AND METHODS: We conducted a cross-sectional survey among primary hypothyroidism patients who met the inclusion criteria in the Qassim region of Saudi Arabia using a questionnaire with demographic characteristics, clinical factors, the 12-Item Medication Adherence Scale, and the Brief Illness Perception Questionnaire (BIPQ). We included 400 patients in the analysis. RESULTS: We found a significant positive correlation between BIPQ subscales - personal control, treatment control, and understanding - with all domains of the 12-Item Medication Adherence Scale. The other dimensions of BIPQ subscales did not significantly correlate with medication adherence. However, a high BIPQ overall score was significantly correlated with poor medication adherence. CONCLUSION: This study found a significant correlation between a high BIPQ overall score and poor medication adherence. This finding suggests the need to consider the emotional and cognitive representation of hypothyroidism in hypothyroid patients to improve their treatment adherence.

Correlation of Blood Oxidative Stress Parameters to Indoor Radiofrequency Radiation: A Cross Sectional Study in Jordan.

Background: Electromagnetic pollution is a general health concern worldwide, as cell phone towers are ubiquitous and are located adjacent to or on the roof of schools, and hospitals. However, the health risks are still inconclusive. This cross-sectional study evaluated the potential effect of electromagnetic radiation generated from various resources including cell phone towers on blood glutathione S transferase activity (e-GST) and total antioxidant activity of the Jordanian population. Methods: The power density of three districts in the city of Irbid, Jordan was mapped to generate "outside the houses" and "inside the houses" maps. The effect of categorical variables (gender, using a cell phone, presence of Wi-Fi modem, previous exposure to medical imaging) and continuous variables (distance from the base station, the elevation of the house, the duration of stay in the house, power density outside houses, power density inside houses) on e-GST and total antioxidant activity were investigated. Results: The EMR generated outside the houses-including cell phone towers-did not reach inside the houses at the same power and had no significant influence on e-GST activity. The EMR inside the house, which primarily came from internal resources, has a significant effect on e-GST activity. The duration of stay inside the house, the use of cell phones, and the presence of a Wi-Fi modem had a proportional effect on e-GST activity. The total antioxidant activity was statistically equal between the tested and control groups. Conclusions: Several factors such as building materials restricted the penetration of EMR reaching inside the houses. EMR generated inside rather than outside the houses had a proportional effect on e-GST. The differences in e-GST were compensated successfully by other antioxidant mechanisms. Further research is needed to identify other possible sources of antioxidants, and to evaluate long-term effects and genetic polymorphism.

Brainstem hemorrhage is uncommon and is associated with high morbidity, mortality, and prolonged hospitalization.

OBJECTIVE: To determine the frequency, risk factors, and outcomes of patients with brainstem hemorrhage in stroke center at King Abdulaziz Medical City, Riyadh. METHODS: A retrospective, observational cohort study including all patients with brainstem hemorrhage from January 2014 to December 2017. The clinical presentation, location of hemorrhage, complications and clinical outcomes were analyzed. RESULTS: Of 1921 stroke patients, 219 had hemorrhagic stroke (11.4%), of whom only 10 (4.6%) had brainstem hemorrhage, comprising 0.5% of all stroke patients. All patients were men; mean age was 58.5 years. Most frequent presenting symptoms were headache (70%), unilateral weakness (60%), and loss of consciousness (50%). All patients had hemorrhage in pons, 5 had concomitant cerebellar hemorrhage (50%), one had medullary hemorrhage, and one midbrain hemorrhage (10% each). Mean ICU stay was 17 days; mean hospital stay was 58 days. At the time of discharge, three (30%) had mRS of 0-2, 5 (50%) had mRS of 3-5, whereas 2 (20%) had died. Glasgow coma scale (GCS) of >8 at presentation was associated with a good outcome at three months (p=0.03). Presentation within six hours of symptom onset (p=0.233), hypertension on presentation (p=0.233), and age less than 60 years (p=0.065) did not affect discharge outcomes. CONCLUSION: Brainstem hemorrhage occurred in 0.5% of all stroke patients. It was associated with high morbidity and mortality. Low Glasgow Coma Scale at presentation was associated with poor outcomes.

Suppressor analysis of a histone defect identifies a new function for the hda1 complex in chromosome segregation.

Histones are essential for the compaction of DNA into chromatin and therefore participate in all chromosomal functions. Specific mutations in HTA1, one of the two Saccharomyces cerevisiae genes encoding histone H2A, have been previously shown to cause chromosome segregation defects, including an increase in ploidy associated with altered pericentromeric chromatin structure, suggesting a role for histone H2A in kinetochore function. To identify proteins that may interact with histone H2A in the control of ploidy and chromosome segregation, we performed a genetic screen for suppressors of the increase-in-ploidy phenotype associated with one of the H2A mutations. We identified five genes, HHT1, MKS1, HDA1, HDA2, and HDA3, four of which encode proteins directly connected to chromatin function: histone H3 and each of the three subunits of the Hda1 histone deacetylase complex. Our results show that Hda3 has functions distinct from Hda2 and Hda1 and that it is required for normal chromosome segregation and cell cycle progression. In addition, HDA3 shows genetic interactions with kinetochore components, emphasizing a role in centromere function, and all three Hda proteins show association with centromeric DNA. These findings suggest that the Hda1 deacetylase complex affects histone function at the centromere and that Hda3 has a distinctive participation in chromosome segregation. Moreover, these suppressors provide the basis for future studies regarding histone function in chromosome segregation.

The OsLti6 genes encoding low-molecular-weight membrane proteins are differentially expressed in rice cultivars with contrasting sensitivity to low temperature.

Rice (Oryza sativa L.) is sensitive to chilling particularly at early stages of seedling establishment. Two closely related genes (OsLti6a, OsLti6b), which are induced by low temperature during seedling emergence were isolated from a cold tolerant temperate japonica rice cultivar. These genes are closely related to the Arabidopsis rare cold-inducible (RCI2) and barley low-temperature-inducible (BLT101) genes. Based on direct biochemical and indirect physiological evidence and similarity with a conserved protein domain in the Cluster of Orthologous Groups (COG) database (e.g., yeast PMP3), the rice genes belong to a class of low-molecular-weight hydrophobic proteins involved in maintaining the integrity of the plasma membrane during cold, dehydration and salt stress conditions. Both genes exhibit a genotype-specific expression signature characterized by early and late stress-inducible expression in tolerant and intolerant genotypes, respectively. The differences in temporal expression profiles are consistent with cultivar differences in cold-induced membrane leakiness and seedling vigor. The presence of CRT/DRE promoter cis-elements is consistent with the synchronized expression of OsLti6 genes with the C-repeat binding factor/drought responsive element-binding protein (CBF/DREB) transcriptional activator. The present results indicate that the Oslti6 genes are part of a battery of cold stress defense-related genes regulated by a common switch.