Asymmetric Histone Inheritance: Establishment, Recognition, and Execution.

The discovery of biased histone inheritance in asymmetrically dividing Drosophila melanogaster male germline stem cells demonstrates one means to produce two distinct daughter cells with identical genetic material. This inspired further studies in different systems, which revealed that this phenomenon may be a widespread mechanism to introduce cellular diversity. While the extent of asymmetric histone inheritance could vary among systems, this phenomenon is proposed to occur in three steps: first, establishment of histone asymmetry between sister chromatids during DNA replication; second, recognition of sister chromatids carrying asymmetric histone information during mitosis; and third, execution of this asymmetry in the resulting daughter cells. By compiling the current knowledge from diverse eukaryotic systems, this review comprehensively details and compares known chromatin factors, mitotic machinery components, and cell cycle regulators that may contribute to each of these three steps. Also discussed are potential mechanisms that introduce and regulate variable histone inheritance modes and how these different modes may contribute to cell fate decisions in multicellular organisms.

A single N-terminal amino acid determines the distinct roles of histones H3 and H3.3 in the Drosophila male germline stem cell lineage.

Adult stem cells undergo asymmetric cell divisions to produce 2 daughter cells with distinct cell fates: one capable of self-renewal and the other committed for differentiation. Misregulation of this delicate balance can lead to cancer and tissue degeneration. During asymmetric division of Drosophila male germline stem cells (GSCs), preexisting (old) and newly synthesized histone H3 are differentially segregated, whereas old and new histone variant H3.3 are more equally inherited. However, what underlies these distinct inheritance patterns remains unknown. Here, we report that the N-terminal tails of H3 and H3.3 are critical for their inheritance patterns, as well as GSC maintenance and proper differentiation. H3 and H3.3 differ at the 31st position in their N-termini with Alanine for H3 and Serine for H3.3. By swapping these 2 amino acids, we generated 2 mutant histones (i.e., H3A31S and H3.3S31A). Upon expressing them in the early-stage germline, we identified opposing phenotypes: overpopulation of early-stage germ cells in the H3A31S-expressing testes and significant germ cell loss in testes expressing the H3.3S31A. Asymmetric H3 inheritance is disrupted in the H3A31S-expressing GSCs, due to misincorporation of old histones between sister chromatids during DNA replication. Furthermore, H3.3S31A mutation accelerates old histone turnover in the GSCs. Finally, using a modified Chromatin Immunocleavage assay on early-stage germ cells, we found that H3A31S has enhanced occupancy at promoters and transcription starting sites compared with H3, while H3.3S31A is more enriched at transcriptionally silent intergenic regions compared to H3.3. Overall, these results suggest that the 31st amino acids for both H3 and H3.3 are critical for their proper genomic occupancy and function. Together, our findings indicate a critical role for the different amino acid composition of the N-terminal tails between H3 and H3.3 in an endogenous stem cell lineage and provide insights into the importance of proper histone inheritance in specifying cell fates and regulating cellular differentiation.

Asymmetric Histone Inheritance in Asymmetrically Dividing Stem Cells.

Epigenetic mechanisms play essential roles in determining distinct cell fates during the development of multicellular organisms. Histone proteins represent crucial epigenetic components that help specify cell identities. Previous work has demonstrated that during the asymmetric cell division of Drosophila male germline stem cells (GSCs), histones H3 and H4 are asymmetrically inherited, such that pre-existing (old) histones are segregated towards the self-renewing GSC whereas newly synthesized (new) histones are enriched towards the differentiating daughter cell. In order to further understand the molecular mechanisms underlying this striking phenomenon, two key questions must be answered: when and how old and new histones are differentially incorporated by sister chromatids, and how epigenetically distinct sister chromatids are specifically recognized and segregated. Here, we discuss recent advances in our understanding of the molecular mechanisms and cellular bases underlying these fundamental and important biological processes responsible for generating two distinct cells through one cell division.

COVID-19 pandemic: Insights into structure, function, and hACE2 receptor recognition by SARS-CoV-2.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a newly emerging, highly transmissible, and pathogenic coronavirus in humans that has caused global public health emergencies and economic crises. To date, millions of infections and thousands of deaths have been reported worldwide, and the numbers continue to rise. Currently, there is no specific drug or vaccine against this deadly virus; therefore, there is a pressing need to understand the mechanism(s) through which this virus enters the host cell. Viral entry into the host cell is a multistep process in which SARS-CoV-2 utilizes the receptor-binding domain (RBD) of the spike (S) glycoprotein to recognize angiotensin-converting enzyme 2 (ACE2) receptors on the human cells; this initiates host-cell entry by promoting viral-host cell membrane fusion through large-scale conformational changes in the S protein. Receptor recognition and fusion are critical and essential steps of viral infections and are key determinants of the viral host range and cross-species transmission. In this review, we summarize the current knowledge on the origin and evolution of SARS-CoV-2 and the roles of key viral factors. We discuss the structure of RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 and its significance in drug discovery and explain the receptor recognition mechanisms of coronaviruses. Further, we provide a comparative analysis of the SARS-CoV and SARS-CoV-2 S proteins and their receptor-binding specificity and discuss the differences in their antigenicity based on biophysical and structural characteristics.

Mitotic drive in asymmetric epigenetic inheritance.

Asymmetric cell division (ACD) produces two daughter cells with distinct cell fates. This division mode is widely used during development and by adult stem cells during tissue homeostasis and regeneration, which can be regulated by both extrinsic cues such as signaling molecules and intrinsic factors such as epigenetic information. While the DNA replication process ensures that the sequences of sister chromatids are identical, how epigenetic information is re-distributed during ACD has remained largely unclear in multicellular organisms. Studies of Drosophila male germline stem cells (GSCs) have revealed that sister chromatids incorporate pre-existing and newly synthesized histones differentially and segregate asymmetrically during ACD. To understand the underlying molecular mechanisms of this phenomenon, two key questions must be answered: first, how and when asymmetric histone information is established; and second, how epigenetically distinct sister chromatids are distinguished and segregated. Here, we discuss recent advances which help our understanding of this interesting and important cell division mode.

Knowledge, Attitude and Practice about Hearing Impairment among the parents of children posted for Cochlear Implantation.

INTRODUCTION: Audition is essential for communication, and it is vital for the normal cognitive development of children. Hence, if a child has a hearing impairment, it would significantly impact the child's speech and language development, competence, and emotional wellness. Most children with hearing impairment are advised to go for amplification devices or cochlear implantations for communication through oral modality. There are numerous factors upon which the rehabilitation programs' outcomes depend; one critical aspect that influences habilitation/rehabilitation is parents' knowledge regarding hearing impairment, their attitude towards it, and their practice. Therefore, it needed to assess the parental knowledge, attitude, and practice among parents of children with hearing impairment. METHOD: The study used a cross-sectional study design and a convenient sampling method to recruit the participants. It was a timebound study; all the cases were recruited as participants during the study period. RESULTS: The developed questionnaire has good reliability and validity. The questionnaire was administered to 38 parents to assess their knowledge, attitude, and practice towards their children's hearing impairment. The study's finding revealed that the overall parental knowledge, attitude, and practice towards their children's hearing impairment was found to be good. CONCLUSION: The developed questionnaires in Hindi have good reliability and validity to assess parental knowledge, attitude, and practice about hearing impairment among parents of children with hearing impairment.

Development, Validation and Reliability of a Questionnaire to Assess Awareness, Knowledge, and Practice about Hearing Impairment Among School Teachers.

BACKGROUND: Hearing impairment is the most common congenital anomaly. It is well known that teachers are the corner pillar for inclusive education. OBJECTIVE: The study aimed to develop a tool that evaluates awareness, knowledge, and practice about Hearing impairment among Teachers and to validate, and test the reliability of the questionnaire. METHODS: A cross-sectional study design and convenient sampling was used to recruit 82 participants. The questionnaire was developed after a familiarity check from Kannada language experts then it was intended for content validation by 6 experts in the field of Audiology. The finalized questionnaire was filled by participants and tested for internal consistency and test-retest reliability. RESULTS: In the current study finalized questionnaire consisted of 50 questions. The scale content validation index (S-CVI) was shown to be good with 0.944 S-CVI. The internal consistency showed moderate-good internal consistency in the independent section and very high overall reliability with a value of 0.898. Further test-retest reliability showed no significant difference (p>0.05) in independent and overall scores of test and retest sessions, respectively. Individual domain and total score intraclass coefficients revealed 'high' test-retest reliability. CONCLUSION: The currently developed questionnaire in the Kannada language to assess teachers' awareness, knowledge, and practice about hearing impairment showed high reliability and validity, making it an efficient tool to assess the gaps between regular school teachers on children with hearing impairment.

DPIO Function among Normal Hearing Middle-Aged Adults in Sudarshan Kriya Yoga Practitioners and Non-Practitioners.

The cochlea, to function efficiently towards hearing, the oxygenated blood supply is a very essential component. Yoga, a practice that originated in ancient India, claims to facilitate physical, mental, and spiritual well-being. Sudarshan Kriya Yoga (SKY) is one such practice that focuses on breathing, therefore, regulating the oxygen circulation in our body. The benefits on practicing SKY have been reported to increase oxygenated blood supply to the respective cells or tissues. DPIO is a measure of cochlear growth function that reflects the basilar membrane function and is sensitive to even a small alteration in the amount of function. Therefore, to analyze if there is an increase in the hair cell function, we compare it between the SKY practitioners and a control group of 70 middle-aged adults (40-65 years old; 35 subjects in each group) who have their hearing sensitivity within normal limits through DPIO measure. Student 't' test was used to compare the mean difference between the two groups. The results revealed that there is a significant difference between both groups with respect to the DPIO amplitude (p-value ≤ 0.05). The study concludes enhanced amplitude on DPIO measure among individuals who practice SKY when compared to nonpractitioners of SKY.

A cluster of children with facial nerve palsy in a high prevalence area for COVID-19.

BACKGROUND: COVID-19 is a disease of varying presentation and neurological sequelae of the disease are being studied. Following a cluster of paediatric facial nerve palsy (FNP) cases in an area of South Wales with a high prevalence of COVID-19, we conducted an opportunistic study to determine whether there has been an increase of incidence of FNP and if there is an association between the FNP and COVID-19 in children. METHODS: We performed a retrospective review of the incidence of FNP between 2015 and 2020 across two hospitals within the health board. The incidence was compared with that in 2020 including a cluster of six children in 14 weeks, presenting to Royal Glamorgan Hospital between June and October. RESULTS: There were 48 cases of children with FNP across both hospital within the study years. Seven (7) cases in 2020. The incidence was not statistically different in comparison to other years. Five out of six of these children in 2020 had antibody testing for COVID-19. All serology testing (100%) returned negative for SARS-CoV- 2 antibodies. CONCLUSIONS: In high prevalence area for COVID-19, cases of children with FNP have not shown a commensurate increase. we have found no causal link between COVID-19 and FNP in children. While this is a small study, larger cohort studies are needed to support this finding. As new strains of COVID-19 are being reported in UK, South Africa and Brazil, physicians need to continue to be vigilant for consistent pattern of signs and symptoms, especially in children.

Spatial and seasonal variability in the water chemistry of Kabar Tal wetland (Ramsar site), Bihar, India: multivariate statistical techniques and GIS approach.

This study was performed to evaluate the spatial and temporal distribution of major ions in water samples of a newly designated Ramsar site, namely Kabar Tal (KT) wetland of Bihar. Samples were collected during summer, monsoon, and winter seasons. The analytical and GIS results show that concentration of electrical conductivity, chloride, and nitrate are higher in summer than monsoon and winter. However, the concentration of major cations such as sodium, potassium, calcium, and magnesium are higher in winter than monsoon and summer. In addition, major anions like sulphate and phosphate concentration is higher during monsoon than summer and winter. Multivariate statistical tool (discriminant analysis) results suggest that temperature, pH, electrical conductivity, sulphate, and potassium are the major parameters distinguishing the water quality in different seasons. The study confirms that seasonal variations are playing a major role in the hydrochemistry of KT wetland. Overall, this work outlines the approach towards proper conservation and utilization of wetlands and to assess the quality of surface water for determining its suitability for agricultural purposes. Overall, this work highlights the approach towards estimating the seasonal dynamics of chemical species in KT wetland and its suitability for irrigation purposes.

Effect of Sudarsankriya yoga practices on P300 amplitude and latency.

The cognitive ability which was perceived as a constant trait, is now understood to be upgraded by adaptive and extended training. Yoga practices are known to sharpen the intellect and enhance concentration. In the initial period of practicing yoga as an alternative/supporting tool to medical line of treatment, it is essential to investigate effect of yoga on cognitive ability using objective method, in order to establish evidences. Hence, aim of this study was to explore the effect of regular practice of sudarsankriya yoga on auditory event related potential (P300) by recording and comparing peak latency and amplitude. The participants were divided into three groups with Group I and Group II participants practicing sudarsankriya yoga for more than 36 months and less than 36 months respectively. Group III were non-practitioners with no prior practice of any form of yoga. Twenty participants in each group with a total of 60 participants between 40 to 65 years of age were recruited for the study. Results revealed a significant difference for mean latency and amplitude between three groups. Findings of the current study suggest that sudarsankriya yoga practices slows down the process of aging effect or maintains on cognitive ability in adults.

Siderophore-assisted cadmium hyperaccumulation in Bacillus subtilis.

Siderophores (Gk iron carriers) are low molecular weight secondary metabolites produced by bacteria, fungi, and plants that have strong binding affinity for iron. Owing to their iron-chelating ability, they are produced mainly when the organism faces iron scarcity. The present study empirically investigated the importance of applying hydroxamate siderophore extracted from Aspergillus nidulans to the cells of Bacillus subtilis for bioremediation of cadmium salt. This investigation deals with siderophore-mediated intracellular Cd accumulation by bacterial cells, growth estimation, biochemical assays like lipid peroxidation, total protein content, carbohydrate content, and iron content estimation. In silico docking and STRING analyses revealed specific interaction between Aspergillus siderophore and receptors present on B. subtilis. Estimation of intracellular Cd by atomic absorption spectroscopy showed more accumulation of Cd ions by B. subtilis in the presence of hydroxamate siderophore. This suggests a possibility of confiscating environmental Cd2+ by utilizing metal chelation property of siderophores and hence can lead to emerging bioremediation mechanisms for heavy metals. In silico studies support experimental investigation and suggest higher affinity of siderophore for Cd ions as compared with ferric ions.

Psycho acoustical Measures in Individuals with Congenital Visual Impairment.

INTRODUCTION: In congenital visual impaired individuals one modality is impaired (visual modality) this impairment is compensated by other sensory modalities. There is evidence that visual impaired performed better in different auditory task like localization, auditory memory, verbal memory, auditory attention, and other behavioural tasks when compare to normal sighted individuals. OBJECTIVE: The current study was aimed to compare the temporal resolution, frequency resolution and speech perception in noise ability in individuals with congenital visual impaired and normal sighted. METHODS: Temporal resolution, frequency resolution, and speech perception in noise were measured using MDT, GDT, DDT, SRDT, and SNR50 respectively. Twelve congenital visual impaired participants with age range of 18 to 40 years were taken and equal in number with normal sighted participants. All the participants had normal hearing sensitivity with normal middle ear functioning. RESULTS: Individual with visual impairment showed superior threshold in MDT, SRDT and SNR50 as compared to normal sighted individuals. This may be due to complexity of the tasks; MDT, SRDT and SNR50 are complex tasks than GDT and DDT. CONCLUSION: Visual impairment showed superior performance in auditory processing and speech perception with complex auditory perceptual tasks.

Isolation of useful scented rice mutants and comparative assessment of genetic diversity.

A set of 36 scented rice mutants were developed through recurrent mutagenesis Pusa basmati-1, Pusa Sugandha-2 and Ketakijoha local with ethyl methane sulphonate (EMS), N-methyl N-nitro N-nitrosoguanidine (NG) and a combination of 0.4% EMS and 0.015% NG over two successive generations. ORM 256-8-10 and ORM 256-8-6 (mutants of PB-1) and ORM 228-1 (mutant of Pusa Sugandha 2) had shown significantly higher grain yield than Geetanjali (standard check), as well as, their respective parent varieties. The above test genotypes were analysed by 12 RAPD and 11 ISSR primers. RAPD and ISSR primers amplified 92 and 77 bands ranging from 4-15 and 4-12 bands per respective primer exhibiting higher level of polymorphism (86.95% and 94.80%). RAPD primer OU 1 and ISSR primer OUAT 7 produced maximum number of 15 (280-1830bp) and 12 polymorphic bands (420-1260bp), respectively. ISSR revealed higher polymorphic information content (PIC) values than RAPD primers indicating better allelic diversity. Resolving power revealed higher efficiency of RAPD primers. OU-1 with high GC content (80%) and two ISSR primers OUAT-7 (GC = 66.7%) and OUAT-15 (GC = 88.2%) produced higher number of polymorphic amplicons. ORM 228-1, Pusa Sugandha-2, ORM 256-8-10 and Ketakijoha were identified to be highly divergent genotypes based on RAPD and ISSR analyses. RAPD analysis revealed divergence of ORM 256-2 and ORM 256-8-12 while ORM 256-8-6 isolated from rest of the genotypes in case of ISSR. This could be attributed to genotype-specific RAPD and ISSR alleles. The above diverse genotypes with high yield identified in the present pursuit would enrich the basmati gene pool for further genetic improvement for grain quality and yield per se.

Assessment of genetic diversity in quality protein maize(QPM) inbreds using ISSR markers.

Genetic diversity of 49 maize inbreds was assessed using twelve ISSR primers. A wide variation in PCR products was revealed in terms of size (280 to 3000 bp), extent of polymorphism (94.87%) and number of bands (4-9). As a whole, 78 ISSR bands were produced (including four monomorphic bands) with an average of 6.5 bands per primer and the maximum number of bands (9) being produced by primer OUAT-8. Five ISSR primers (OUAT-8, OUAT-9, OUAT-15, OUAT 17 and OUAT-18) revealed higher PIC value (around 0.70) along with 100% polymorphism indicating better allelic diversity. While, ISSR primer OUAT-15 revealed higher number of polymorphic bands (8) with 100% polymorphism as well as considerably high PIC and Rp values. Thus, such an informative and discriminative primer is of immense value for the study of genetic diversity in a set of maize genotypes. The similarity index values ranged from 0.3 to 0.9 with an average of 0.522 and BQPM-1-14 maintained the highest genetic distance as revealed from its lowest average similarity coefficient value (0.393) with rest of the genotypes. BQPM 1-14, BQPM 1-8, BQPM 3-10, BQPM 6-8 and B 1110-7-2 were identified to be highly divergent among the test inbreds which could be sorted out as valuable materials for heterosis breeding for production of single cross hybrids.

A Comparative Study of the Effectiveness and Safety of Topical Calcipotriol and Topical Methotrexate in Chronic Plaque Psoriasis.

Background Psoriasis is a papulosquamous disease with variable morphology, distribution, severity, and course. Chronic plaque psoriasis, or psoriasis vulgaris, is the most common form of psoriasis. Present available preparations for mild to moderate chronic plaque psoriasis for topical use are local corticosteroids, coal tar, dithranol, tazarotene, calcipotriol, tapinarof, and calcineurin inhibitors. However, every preparation has its disadvantages. Calcipotriol, an active form of vitamin D, is available in topical form for dermatological use. Chronic plaque psoriasis is the chief medical use of calcipotriol for mild to moderate form. Methotrexate has dramatic results in psoriasis when used systemically. Now, topical formulation is being advocated in localized psoriasis, which is not associated with the side effects of the systemic form. Therefore, this study aimed to compare the effectiveness of topical calcipotriol and topical methotrexate on the basis of the psoriasis area severity index (PASI) in patients of chronic plaque psoriasis and compare their safety in terms of adverse effects. Methodology The total number of patients included in the study was 60. They were divided into two groups, with 30 patients each. One group was prescribed ointment calcipotriol 0.005% twice daily local application (Group C). The other group was prescribed methotrexate gel 1% twice daily local application (Group M). The patients were followed up on the fourth and eighth weeks, and at each time, thorough clinical examinations were conducted for all patients. The PASI score was calculated in each patient every time. Safety was assessed by biochemical parameters, and tolerability was assessed by the incidence of adverse effects. All the patients included in the study were investigated at baseline, fourth week, and eighth week. The data collected were transferred to a master chart and analyzed. Results For the patients in group C, the mean PASI score at 0 week was 5.93 ± 2.62, while at four weeks, the mean PASI score declined to 1.67 ± 1.13, and at eight weeks, the mean PASI score further declined to 0.67 ± 0.68. For the patients in group M, the mean PASI score at 0 week was 5.91 ± 2.22, while at four weeks, the mean PASI score declined to 1.91 ± 1.11, and at eight weeks, the mean PASI score further declined to 0.89 ± 0.72. Furthermore, there was no significant difference in the mean PASI score at various time points when compared between the two groups (p-value = 0.761, 0.296, 0.079, respectively). Thus, both drugs seem to be effective in treating mild- to moderate-grade chronic plaque psoriasis. Most of the patients in both groups showed marked clearance of the lesions. However, there were six patients in the calcipotriol group showing complete clearance of the lesions having mild-degree plaque psoriasis, as compared to three patients in the methotrexate group. In the present study, based on the comparison of safety and tolerability, four out of 30 patients (13.3%) in the calcipotriol group suffered skin irritation, whereas six out of 30 patients (20%) in the methotrexate group complained of a burning sensation. The adverse effects seen in the patients were transient and mild. Conclusion Topical calcipotriol and methotrexate were effective in reducing lesions in patients with chronic mild to moderate plaque psoriasis. Both drugs were well tolerated with mild and transient adverse effects and did not alter hematological and biochemical parameters.

Qualitative exploration for the under-foot fall in utilization of health services at Primary Health Center of Shahdol, Madhya Pradesh.

Background: Despite efforts to improve healthcare infrastructure and service delivery, significant disparities in healthcare utilization persist, leading to suboptimal health outcomes and hindering progress toward achieving universal health coverage. This research article aims to conduct a qualitative exploration of the under-foot fall in utilization of health services, shedding light on the barriers and challenges faced by individuals in accessing and utilizing health care to inform targeted interventions and improve health service utilization. Methods: This qualitative study employed free listing, pile sorting, and focus group discussions (FGDs) as data collection methods. Representatives from various stakeholders involved in the primary healthcare delivery system were selected based on their vocalness, knowledge, willingness to participate, and heterogeneity of responses. Subsequently, FGDs and key informant interviews (KIIs) were conducted to further explore the identified barriers. The collected transcripts underwent manual thematic analysis using coding rules and theme generation procedures. Results: A total of 30 participants, including healthcare providers, community leaders, and individuals from the local community, took part in the qualitative exploration. The themes encompassed limited awareness and knowledge, geographical and infrastructural barriers, socioeconomic constraints, trust and perceptions of the healthcare system, and cultural and social factors. These findings provide valuable insights into the multifaceted barriers hindering healthcare utilization and can guide the development of targeted interventions and policies to improve healthcare access and delivery in the study area. Conclusion: The identified barriers, including limited awareness and knowledge, geographical and infrastructural challenges, socioeconomic constraints, trust and perceptions of the healthcare system, cultural and social factors, and gender disparities, are consistent with the existing literature.

Geochemical fractionation, bioavailability, and ascertaining ecological risk of phosphorus in surface and core sediments of mangroves, western coast of India.

Phosphorus (P), a crucial macronutrient, is essential in the maintenance of ecosystem productivity and the biogeochemical processes of other biogenic substances found in marine settings. The aim of the present study is to quantify the different geochemical fractions, bioavailability, and ecological risk of phosphorus in surface and core sediment of mangroves, Gulf of Kachchh (GoK). To better understand the P dynamics, sequential chemical extraction techniques were used to study sediment P pool distribution such as exchangeable P; Fe-bound P; authigenic P; detrital P; and organic P. The total sedimentary P ranged from 539.51 to 7217.24 mg/kg in pre-monsoon and 487.04 to 7180.26 mg/kg in post-monsoon, and was primarily composed of inorganic P. Authigenic P and Fe-bound P were the dominant fractions of P in surface and core sediments, exhibiting a significant long-term P reservoir. Sources such as riverine inputs, industrial and sewage discharge, aquaculture farms, and seaport operations all have an impact on the P dynamics in GoK. Furthermore, organic matter, pH, ORP, and diagenetic processes in sedimentary environment have influenced P retention and release. FeBD:Fe-P ratio indicates the presence of Fe matrices, having strong adsorption potential for P, with the availability of a surplus of Fe(III) (oxy)hydroxides serving as a significant P pool, governing the P dynamics. The P enrichment index (PEI) showed that sediments were highly impacted by anthropogenic P and could cause a high ecological risk. Bioavailable phosphorus (BAP) suggests the availability of an ample amount of bioavailable P fractions (average of 49.70% post-monsoon and 44.64% post-monsoon) in surface sediments. Sites 3, 13, 14, 20, 21, and 26 exhibited considerably higher BAP. Core 1 comprised significantly higher BAP (60.52%). Thus, sediments of GoK could act as a source of P to the overlying water if released from sediments.

Reduced Levels of Lagging Strand Polymerases Shape Stem Cell Chromatin.

Stem cells display asymmetric histone inheritance while non-stem progenitor cells exhibit symmetric patterns in the Drosophila male germline lineage. Here, we report that components involved in lagging strand synthesis, such as DNA polymerase α and δ (Polα and Polδ), have significantly reduced levels in stem cells compared to progenitor cells. Compromising Polα genetically induces the replication-coupled histone incorporation pattern in progenitor cells to be indistinguishable from that in stem cells, which can be recapitulated using a Polα inhibitor in a concentration-dependent manner. Furthermore, stem cell-derived chromatin fibers display a higher degree of old histone recycling by the leading strand compared to progenitor cell-derived chromatin fibers. However, upon reducing Polα levels in progenitor cells, the chromatin fibers now display asymmetric old histone recycling just like GSC-derived fibers. The old versus new histone asymmetry is comparable between stem cells and progenitor cells at both S-phase and M-phase. Together, these results indicate that developmentally programmed expression of key DNA replication components is important to shape stem cell chromatin. Furthermore, manipulating one crucial DNA replication component can induce replication-coupled histone dynamics in non-stem cells in a manner similar to that in stem cells.

Trace metal fractionation in the Pichavaram mangrove-estuarine sediments in southeast India after the tsunami of 2004.

The geochemistry of coastal sediments of southern India was altered after the tsunami in 2004. A five-step sequential extraction procedure was applied to assess the effects of tsunami on mobility and redistribution of selected elements (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn). Ten surface sediments and three cores were analyzed for different metal fractions (exchangeable, carbonate, reduced, oxidized, and residual). Total metal concentrations increased in mangrove sediments after the tsunami, but their spatial distribution did not show significant variation (except Mn). The sediments were mixed by the tsunami, and there was lack of variation in metal concentrations in different fractions with depth (except Pb and Mn). High concentrations of Pb and Zn occurred in the oxide fractions, whereas Cu, Cr, Cd, and Ni were high in the organic and sulfide-rich fractions. Metals in the residual fraction (lattice bound) had the highest concentration suggesting their non-availability and limited biological uptake in the system. Most of the metals (except Mn) do not constitute a risk based on the different geochemical indices.