Relationship between calcium and agar on vitrification and shoot-tip necrosis of quince (Cydonia oblonga Mill.) shoots in vitro

Shoot-tip cultures of Quince C (Cydonia oblonga Mill.) initiated on Murashige & Skoog (MS) medium containing 5 M BA and 0.6% Phytagar showed both shoot-tip necrosis and severe vitrification. Culturing explants on medium containing 1.2% Phytagar and Ca levels of 3 mM (MS medium), 18 mM and 30 mM showed a decrease in growth with increasing medium Ca levels, being especially severe at 30 mM. The Ca content of the explants increased linearly with increasing medium Ca. Culturing explants on medium containing 3 mM, 9 mM, and 18 mM Ca at 0.6, 0.9, and 1.2% agar resulted in reduction in growth, shoot-tip necrosis, and vitrification when either factor was increased. The reduction in shoot-tip necrosis could be accounted for primarily by an increase in medium Ca levels but may also be affected by a change in explant growth. Increasing Ca concentration in the medium resulted in a linear increase in explant K, Ca, Mg, and B levels and a decrease in Mn and Na. Although increasing medium Ca or agar levels reduced vitrification, it is unclear whether they were the direct cause of the reduction in vitrification or whether this response was an effect of the reduction in culture fresh weight.Approved by publication by the Director, West Virginia Agriculture anf Forestry Experimental Station as Scientific Article No. 2199     

Rapidly evolving CRISPRs implicated in acquired resistance of microorganisms to viruses

Recent experimental evidence has demonstrated that bacteria acquire resistance to viruses by incorporation of short transcribed nucleotide sequences into regions of clustered regularly interspaced short palindromic repeats (CRISPR). We have analysed community genomic data from acidophilic microbial biofilms and discovered that evolution of the CRISPR regions in two distinct Leptospirillum group II bacteria occurs fast enough to promote individuality in otherwise nearly clonal populations. Comparative genomics strongly indicates very recent lateral transfer of the CRISPR locus between these populations, followed by significant loss of spacer sequences and locus expansion by unidirectional heterogeneous addition of new spacer sequences. Diversification of the CRISPR region is inferred to be a population-level response to the rapidly changing selective pressure of phage predation. Results reinforce the importance of phage–host interactions in shaping microbial ecology and evolution over very short time scales.     

Trisomy 17 in a baboon (Papio hamadryas) with polydactyly, patent foramen ovale and pyelectasis

Trisomy 13 in humans is the third most common autosomal abnormality at birth, after trisomy 21 and trisomy 18. It has a reported incidence of between 1:5,000 and 1:30,000 live births. It is associated with multiple abnormalities, many of which shorten lifespan. We describe here the first reported case of a baboon (Papio hamadryas) with trisomy of chromosome 17, which is homologous to human chromosome 13. The trisomic infant was born to a consanguineous pair of baboons and had morphological characteristics similar to those observed in human trisomy 13, including bilateral polydactyly in the upper limbs, a patent foramen ovale, and pyelectasis. Molecular DNA analysis using human chromosome 13 markers was consistent with the affected infant inheriting two copies of chromosome 17 derived from the same parental chromosome. This trisomy was, therefore, due to either an error in meiosis II or the result of postzygotic nondisjunction. The parental origin, however, could not be determined.     

Diverse populations of lake water bacteria exhibit chemotaxis towards inorganic nutrients

Chemotaxis allows microorganisms to rapidly respond to different environmental stimuli; however, understanding of this process is limited by conventional assays, which typically focus on the response of single axenic cultures to given compounds. In this study, we used a modified capillary assay coupled with flow cytometry and 16S rRNA gene amplicon pyrosequencing to enumerate and identify populations within a lake water microbial community that exhibited chemotaxis towards ammonium, nitrate and phosphate. All compounds elicited chemotactic responses from populations within the lake water, with members of Sphingobacteriales exhibiting the strongest responses to nitrate and phosphate, and representatives of the Variovorax, Actinobacteria ACK-M1 and Methylophilaceae exhibiting the strongest responses to ammonium. Our results suggest that chemotaxis towards inorganic substrates may influence the rates of biogeochemical processes.     

Hepatic overexpression of hormone-sensitive lipase and adipose triglyceride lipase promotes fatty acid oxidation, stimulates direct release of free fatty acids, and ameliorates steatosis

Hepatic steatosis is often associated with insulin resistance and obesity and can lead to steatohepatitis and cirrhosis. In this study, we have demonstrated that hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), two enzymes critical for lipolysis in adipose tissues, also contribute to lipolysis in the liver and can mobilize hepatic triglycerides in vivo and in vitro. Adenoviral overexpression of HSL and/or ATGL reduced liver triglycerides by 40-60% in both ob/ob mice and mice with high fat diet-induced obesity. However, these enzymes did not affect fasting plasma triglyceride and free fatty acid levels or triglyceride and apolipoprotein B secretion rates. Plasma 3-beta-hydroxybutyrate levels were increased 3-5 days after infection in both HSL- and ATGL-overexpressing male mice, suggesting an increase in beta-oxidation. Expression of genes involved in fatty acid transport and synthesis, lipid storage, and mitochondrial bioenergetics was unchanged. Mechanistic studies in oleate-supplemented McA-RH7777 cells with adenoviral overexpression of HSL or ATGL showed that reduced cellular triglycerides could be attributed to increases in beta-oxidation as well as direct release of free fatty acids into the medium. In summary, hepatic overexpression of HSL or ATGL can promote fatty acid oxidation, stimulate direct release of free fatty acid, and ameliorate hepatic steatosis. This study suggests a direct functional role for both HSL and ATGL in hepatic lipid homeostasis and identifies these enzymes as potential therapeutic targets for ameliorating hepatic steatosis associated with insulin resistance and obesity.     

Increased risk of peripheral arterial disease in polymyalgia rheumatica: a population-based cohort study

Introduction  

The present study was conducted to determine whether patients with polymyalgia rheumatica (PMR) are at an increased risk of peripheral arterial disease (PAD).     

Developmental competence of morphologically poor oocytes in relation to follicular size and oocyte diameter in the pig

The objective of this study was to assess the practical usefulness of morphologically poor oocytes (MPCOCs) in relation to follicular size and oocyte diameter. Oocytes collected from medium (3–8 mm in diameter) and small (<3 mm) follicles were classified into five categories of morphologically good oocytes (MGCOCs) from medium follicles (MA, control), MPCOCs with larger and smaller diameters from medium follicles (ML and MS, respectively), and those from small follicles (SL and SS, respectively). The oocytes were examined for maturation and developmental competence after parthenogenesis and somatic cell nuclear transfer (SCNT). Nuclear maturation of ML oocytes (91%) was similar to that of control oocytes (94%), but higher than MS (80%), SL (79%), and SS (63%) oocytes. This pattern was also observed in the intracellular glutathione level, p34^cdc2 kinase activity, and gene (CDK1, PCNA, and ERK2) expression levels in in vitro‐matured oocytes. ML oocytes showed a similar proportion of blastocyst formation (20%) after SCNT to control oocytes (21%). In addition, the use of ML oocytes resulted in a 50% farrowing rate with 1.8% efficiency of piglet production after SCNT embryo transfer, while control oocytes showed a 60% farrowing rate with 2.4% production efficiency. Our results demonstrate that MPCOCs, if appropriately selected, have a comparable ability to MGCOCs in supporting not only in vitro blastocyst formation, but also development to term in vivo after SCNT. These oocytes can be used as a source for in vitro production of embryos with normal in vivo viability in pigs. Mol. Reprod. Dev. 77: 330–339, 2010. © 2009 Wiley‐Liss, Inc.     

An engineered class I transfer RNA with a class II tertiary fold

Structure-based engineering of the tertiary fold of Escherichia coli tRNA(Gln)2 has enabled conversion of this transfer RNA to a class II structure while retaining recognition properties of a class I glutamine tRNA. The new tRNA possesses the 20-nt variable stem-loop of Thermus thermophilus tRNA(Ser). Enlargement of the D-loop appears essential to maintaining a stable tertiary structure in this species, while rearrangement of a base triple in the augmented D-stem is critical for efficient glutaminylation. These data provide new insight into structural determinants distinguishing the class I and class II tRNA folds, and demonstrate a marked sensitivity of glutaminyl-tRNA synthetase to alteration of tRNA tertiary structure.     

Effect of postal prompts to patients and general practitioners on the quality of primary care after a coronary event (POST): randomised controlled trial

ObjectivesTo determine whether postal prompts to patients who have survived an acute coronary event and to their general practitioners improve secondary prevention of coronary heart disease.DesignRandomised controlled trial.Setting52 general practices in east London, 44 of which had received facilitation of local guidelines for coronary heart disease.Participants328 patients admitted to hospital for myocardial infarction or unstable angina.InterventionsPostal prompts sent 2 weeks and 3 months after discharge from hospital. The prompts contained recommendations for lowering the risk of another coronary event, including changes to lifestyle, drug treatment, and making an appointment to discuss these issues with the general practitioner or practice nurse.ResultsPrescribing of β bockers (odds ratio 1.7, 95% confidence interval 0.8 to 3.0, P>0.05) and cholesterol lowering drugs (1.7, 0.8 to 3.4, P>0.05) did not differ between intervention and control groups. A higher proportion of patients in the intervention group (64%) than in the control group (38%) had their serum cholesterol concentrations measured (2.9, 1.5 to 5.5, P<0.001). Secondary outcomes were significantly improved for consultations for coronary heart disease, the recording of risk factors, and advice given. There were no significant differences in patients’ self reported changes to lifestyle or to the belief that it is possible to modify the risk of another coronary event.ConclusionsPostal prompts to patients who had had acute coronary events and to their general practitioners in a locality where guidelines for coronary heart disease had been disseminated did not improve prescribing of effective drugs for secondary prevention or self reported changes to lifestyle. The prompts did increase consultation rates related to coronary heart disease and the recording of risk factors in the practices. Effective secondary prevention of coronary heart disease requires more than postal prompts and the dissemination of guidelines.

Key messages

• Postal prompts to patients and their general practitioners about effective secondary prevention after a myocardial infarction did not improve the prescribing of cholesterol lowering drugs and β blockers
• The prompts did improve general practice recording of cardiovascular risk factors and lifestyle advice given to patients, but they made no difference to patients’ reports of changes to lifestyle
• Other methods are needed to improve the quality of secondary prevention of coronary heart disease in general practice