Inversions over the terminus region in Salmonella and Escherichia coli: IS200s as the sites of homologous recombination inverting the chromosome of Salmonella enterica serovar typhi

Genomic rearrangements (duplications and inversions) in enteric bacteria such as Salmonella enterica serovar Typhimurium LT2 and Escherichia coli K12 are frequent (10(-3) to 10(-5)) in culture, but in wild-type strains these genomic rearrangements seldom survive. However, inversions commonly survive in the terminus of replication (TER) region, where bidirectional DNA replication terminates; nucleotide sequences from S. enterica serovar Typhimurium LT2, S. enterica serovar Typhi CT18, E. coli K12, and E. coli O157:H7 revealed genomic inversions spanning the TER region. Assuming that S. enterica serovar Typhimurium LT2 represents the ancestral genome structure, we found an inversion of 556 kb in serovar Typhi CT18 between two of the 25 IS200 elements and an inversion of about 700 kb in E. coli K12 and E. coli O157:H7. In addition, there is another inversion of 500 kb in E. coli O157:H7 compared with E. coli K12. PCR analysis confirmed that all S. enterica serovar Typhi strains tested, but not strains of other Salmonella serovars, have an inversion at the exact site of the IS200 insertions. We conclude that inversions of the TER region survive because they do not significantly change replication balance or because they are part of the compensating mechanisms to regain chromosome balance after it is disrupted by insertions, deletions, or other inversions.     

An efficient protocol for shoot regeneration and genetic transformation of pigeonpea [<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millsp.] using leaf explants

A protocol for efficient plant regeneration from leaf explants of pigeonpea [ Cajanus cajan (L.) Millsp.] was developed for the production of transgenic plants. Leaf explants from 4- to 5-day-old in vitro raised seedlings were most efficient in producing multiple adventitious shoots in 90% of the explants on shoot induction medium [Murashige and Skoog (MS) medium +5.0 microM benzyladenine +5.0 microM kinetin]. Shoot buds originated from the petiolar cut end of the explants and elongated rapidly on medium containing 0.58 microM gibberellic acid. Over 80% of the elongated shoots rooted well on MS medium containing 11.42 microM indole-3-acetic acid and were transplanted with 100% success. The procedure reported here is very simple, efficient and reproducible, and is applicable across diverse genotypes of pigeonpea. The usefulness of this system for further studies on the genetic transformation of pigeonpea has been demonstrated in biolistics-mediated gene transfer by using nptII and uidA as marker genes, where 50% of the selected plants showed gene integration and expression.     

Molecular docking analysis of furfural and isoginkgetin with heme oxygenase I and PPARγ

It is of interest to document the molecular docking analysis based binding data of furfural and isoginkgetin with heme oxygenase I and PPARγ in the context of inflammation for further consideration in drug design and development.     

Phenolic allelochemicals released by <Emphasis Type="Italic">Chenopodium murale</Emphasis> affect the growth,nodulation and macromolecule content in chickpea and pea

The present study was conducted to investigate the effect of the residue of Chenopodium murale L. on growth, nodulation and macromolecule content of two legume crops, viz., Cicer arietinum L. (chickpea) and Pisum sativum L. (pea). A significant reduction in root and shoot length as well as dry matter accumulation occurred when both the legumes were grown in the soil amended with 5, 10, 20 and 40 g residue kg⁻¹ soil. In general, a gradual decline in growth was associated with an increasing amount of residues in the soil. There was also a significant reduction in total chlorophyll content and the amounts of protein and carbohydrates (macromolecules) in plants growing in the residue-amended soil. The nodulation was completely absent in chickpea and pea when the plants were grown in the soil amended with 10 and 20 g residue kg⁻¹ soil, respectively. At a lower rate of residue amendment (5 g kg⁻¹ soil), a significant decline in nodule number and weight, and leghaemoglobin content was recorded. Root oxidizability, an indirect measure of tissue viability and cellular respiration, was adversely affected in both the legumes under various treatments of residue amendment. The observed growth reduction concomitant with increased proline accumulation indicated the presence of some inhibitory compounds in the residue-amended soil. It was rich in phenolics identified as protocatechuic, ferulic, p-coumaric and syringic acid with 12.8, 30.4, 20.2 and 33.6% relative content, respectively. The results suggest that the residue of C. murale releases phenolic allelochemicals, which deleteriously affect the growth, nodulation and macromolecule content of chickpea and pea.     

Tuning of the outer hair cell motor by membrane cholesterol

Cholesterol affects diverse biological processes, in many cases by modulating the function of integral membrane proteins. We observed that alterations of cochlear cholesterol modulate hearing in mice. Mammalian hearing is powered by outer hair cell (OHC) electromotility, a membrane-based motor mechanism that resides in the OHC lateral wall. We show that membrane cholesterol decreases during maturation of OHCs. To study the effects of cholesterol on hearing at the molecular level, we altered cholesterol levels in the OHC wall, which contains the membrane protein prestin. We show a dynamic and reversible relationship between membrane cholesterol levels and voltage dependence of prestin-associated charge movement in both OHCs and prestin-transfected HEK 293 cells. Cholesterol levels also modulate the distribution of prestin within plasma membrane microdomains and affect prestin self-association in HEK 293 cells. These findings indicate that alterations in membrane cholesterol affect prestin function and functionally tune the outer hair cell.     

Structure of human hyaluronidase-1, a hyaluronan hydrolyzing enzyme involved in tumor growth and angiogenesis

Mammalian hyaluronidases hydrolyze hyaluronan, a polysaccharide of diverse physiological roles found in all tissues and body fluids. In addition to its function in normal cellular hyaluronan turnover, human hyaluronidase-1 is implicated in cancer proliferation, angiogenesis, and inflammatory diseases; its expression is up-regulated in advanced stages of bladder cancer, whereas the expression of the alternative splice-variants is down-regulated. The crystal structure reveals a molecule composed of two closely associated domains: a catalytic domain that adopts a distorted (beta/alpha)8 barrel resembling that of bee venom hyaluronidase, and a novel, EGF-like domain, characteristic of involvement in protein-protein interactions and regulatory processes. The structure shows that the fold of this unique EGF-like domain is intact in four alternative splice-variants, whereas the catalytic domain is likely to be unfolded. Thus, these variants may function by competing with the full-length enzyme for the putative protein partner and regulating enzymatic activity in healthy cells.     

Integrin-mediated mechanotransduction in renal vascular smooth muscle cells: activation of calcium sparks

Integrins are transmembrane heterodimeric proteins that link extracellular matrix (ECM) to cytoskeleton and have been shown to function as mechanotransducers in nonmuscle cells. Synthetic integrin-binding peptide triggers Ca(2+) mobilization and contraction in vascular smooth muscle cells (VSMCs) of rat afferent arteriole, indicating that interactions between the ECM and integrins modulate vascular tone. To examine whether integrins transduce extracellular mechanical stress into intracellular Ca(2+) signaling events in VSMCs, unidirectional mechanical force was applied to freshly isolated renal VSMCs through paramagnetic beads coated with fibronectin (natural ligand of alpha(5)beta(1)-integrin in VSMCs). Pulling of fibronectin-coated beads with an electromagnet triggered Ca(2+) sparks, followed by global Ca(2+) mobilization. Paramagnetic beads coated with low-density lipoprotein, whose receptors are not linked to cytoskeleton, were minimally effective in triggering Ca(2+) sparks and global Ca(2+) mobilization. Preincubation with ryanodine, cytochalasin-D, or colchicine substantially reduced the occurrence of Ca(2+) sparks triggered by fibronectin-coated beads. Binding of VSMCs with antibodies specific to the extracellular domains of alpha(5-) and beta(1)-integrins triggered Ca(2+) sparks simulating the effects of fibronectin-coated beads. Preincubation of microperfused afferent arterioles with ryanodine or integrin-specific binding peptide inhibited pressure-induced myogenic constriction. In conclusion, integrins transduce mechanical force into intracellular Ca(2+) signaling events in renal VSMCs. Integrin-mediated mechanotransduction is probably involved in myogenic response of afferent arterioles.     

Common mental health problems in immigrants and refugees: general approach in primary care

Background:

Recognizing and appropriately treating mental health problems among new immigrants and refugees in primary care poses a challenge because of differences in language and culture and because of specific stressors associated with migration and resettlement. We aimed to identify risk factors and strategies in the approach to mental health assessment and to prevention and treatment of common mental health problems for immigrants in primary care.

Methods:

We searched and compiled literature on prevalence and risk factors for common mental health problems related to migration, the effect of cultural influences on health and illness, and clinical strategies to improve mental health care for immigrants and refugees. Publications were selected on the basis of relevance, use of recent data and quality in consultation with experts in immigrant and refugee mental health.

Results:

The migration trajectory can be divided into three components: premigration, migration and postmigration resettlement. Each phase is associated with specific risks and exposures. The prevalence of specific types of mental health problems is influenced by the nature of the migration experience, in terms of adversity experienced before, during and after resettlement. Specific challenges in migrant mental health include communication difficulties because of language and cultural differences; the effect of cultural shaping of symptoms and illness behaviour on diagnosis, coping and treatment; differences in family structure and process affecting adaptation, acculturation and intergenerational conflict; and aspects of acceptance by the receiving society that affect employment, social status and integration. These issues can be addressed through specific inquiry, the use of trained interpreters and culture brokers, meetings with families, and consultation with community organizations.

Interpretation:

Systematic inquiry into patients’ migration trajectory and subsequent follow-up on culturally appropriate indicators of social, vocational and family functioning over time will allow clinicians to recognize problems in adaptation and undertake mental health promotion, disease prevention or treatment interventions in a timely way.Changing patterns of migration to Canada pose new challenges to the delivery of mental health services in primary care. For the first 100 years of Canada’s existence, most immigrants came from Europe; since the 1960s, there has been a marked shift, with greater immigration from Asia, Africa, and Central and South America.¹ The mix differs across the provinces, although nearly all immigrants settle in Canada’s largest cities.² The task of preventing, recognizing and appropriately treating common mental health problems in primary care is complicated for immigrants and refugees because of differences in language, culture, patterns of seeking help and ways of coping.^3–6In consultation with experts in immigrant and refugee mental health, we reviewed the literature to determine associated risks and clinical considerations for primary care practitioners in the approach to common mental health problems among new immigrant or refugee patients.^7–10 In this paper, we review the effect of migration on mental health, use of health care and barriers to care. We outline basic clinical strategies for primary mental health care of migrants including the use of interpreters, family interaction and assessment, and working with community resources.