Tolerance ofRhizobium leguminosarum bv.phaseoli to acidity and drought

Ten strains ofRhizobium leguminosarum bv.phaseoli isolated from soils of Morocco were more tolerant than three culture collection strains to acid conditions in culture media or in sterile soil. The survival rate of a tolerant strain in a sandy acid soil was greater than a sensitive strain at different humidity levels. These properties should give locally selected strains an advantage in nodulatingPhaseolus vulgaris roots in soils similar to those used here.     

Reconstitution of human epidermal growth factor receptors and its deletion mutants in cultured hamster cells

DNA sequences encoding the human epidermal growth factor (EGF) receptor and various EGF-receptor deletion mutants were transfected into chinese hamster ovary (CHO) cells devoid of endogenous EGF receptors. A functional human EGF-receptor is expressed on the surface of heterologous CHO cells with the following properties: it exhibits typical high affinity (10%; Kd = 3 X 10(-10) M) and low affinity (90%; Kd = 3 X 10(-9) M) binding sites for 125I-EGF; it is expressed as a polypeptide of 170,000 molecular weight with intrinsic protein tyrosine kinase activity. EGF stimulates the kinase activity leading to self-phosphorylation and to phosphorylation of exogenous substrate; 125I-EGF is rapidly internalized into the CHO cells by receptor mediated endocytosis and; EGF stimulates DNA synthesis in the cells expressing the human EGF-receptor. Deletion of 63 amino acids from the C-terminal end of EGF-receptor, which removes two autophosphorylation sites, abolishes the high affinity state of the receptor. Nevertheless, this receptor mutant is able to undergo endocytosis and to respond mitogenically to EGF to a similar extent as the "wild type" receptor. Further deletions from the cytoplasmic domain give rise to low affinity endocytosis-defective receptor mutants. Finally, deletion of the transmembrane domain of the human receptor yields an EGF-receptor ligand binding domain which is secreted from the cells.     

Mutagens in human urine: effects of cigarette smoking and diet

Human urine from smokers and nonsmokers on strictly controlled diets was assayed for mutagenic activity. Two distinct diets were employed in this study. Diet study A consisted of a high-meat, high-fat diet, observed for 5 days, followed by a vegan diet, adhered to for the next 5 days. The vegan diet contained no meat, fish, eggs, or dairy products. It was comprised of soy products, prepackaged vegan dinners, seeds, nuts, fruits, vegetables, beans and herbal teas. Diet study B consisted of 3 days on a typical western diet followed by a macrobiotic diet of grains and fresh vegetables for 5 days. Portions of 24-h urine samples were assayed in Salmonella typhimurium TA1538. The levels of urinary creatinine and cotinine were measured. Mutagenic activity was observed in the urine of most smokers. However, the levels of mutagens in the urine of light smokers were similar to those of nonsmokers. For both nonsmokers and smokers there was a significant increase in urine mutagenicity when volunteers were on the vegan diet. Several nonsmokers on the vegan diet in diet study A had pronounced mutagenic activity in their urine samples, in some instances at higher levels than that in the urine of smokers on a meat diet. In diet study B no clear differences were observed between the meat diet and the macrobiotic diet. In diet studies A and B the mutagenic potency of smokers' urine could not be correlated with cotinine levels alone or with urinary pH. These data suggest that dietary factors can play a dominant role in the mutagenicity of urine concentrates.     

Influence of iron depletion on growth and production of catechol siderophores by different Frankia strains

Nine strains of Frankia isolated from six Casuarinaceae (including four Casuarina sp., one Allocasuarina and one Gymnostoma) and one Elaeagnaceae (Hippophae¨ rhamnoides) were screened for growth and production of siderophores in an iron-deficient liquid medium. Siderophore production was detected only in four strains (Cj, G2, CH and G82) using the CAS and Arnow assays. Salicylates formed more than 90% and dihydroxybenzoates formed less than 10% of all catechol-type siderophores produced. Growth of the former strains was less affected by iron deficiency than that of strains Rif, Thr, URU, BR and RT which do not produce siderophores. Optimal siderophore production by strain Cj was noted when iron concentration reached 0.5μm and was completely inhibited at an iron concentration of 10μm. The kinetics of siderophore production by strain Cj showed that siderophore synthesis was detectable during the growth stationary phase. Growth of Cj (a siderophore-producing strain) and of RT (a non-siderophore-producing strain) differed when 2,2-dipyridyl or ethylene di(o-hydroxyphenyl) acetic acid (EDDHA) was added to the iron-deficient growth medium. Frankia strain RT was the most sensitive to the detrimental effect of both iron chelators.     

Programmatic Cost Evaluation of Nontargeted Opt-Out Rapid HIV Screening in the Emergency Department

Background

The Centers for Disease Control and Prevention recommends nontargeted opt-out HIV screening in healthcare settings. Cost effectiveness is critical when considering potential screening methods. Our goal was to compare programmatic costs of nontargeted opt-out rapid HIV screening with physician-directed diagnostic rapid HIV testing in an urban emergency department (ED) as part of the Denver ED HIV Opt-Out Trial.

Methods

This was a prospective cohort study nested in a larger quasi-experiment. Over 16 months, nontargeted rapid HIV screening (intervention) and diagnostic rapid HIV testing (control) were alternated in 4-month time blocks. During the intervention phase, patients were offered HIV testing using an opt-out approach during registration; during the control phase, physicians used a diagnostic approach to offer HIV testing to patients. Each method was fully integrated into ED operations. Direct program costs were determined using the perspective of the ED. Time-motion methodology was used to estimate personnel activity costs. Costs per patient newly-diagnosed with HIV infection by intervention phase, and incremental cost effectiveness ratios were calculated.

Results

During the intervention phase, 28,043 eligible patients were included, 6,933 (25%) completed testing, and 15 (0.2%, 95% CI: 0.1%–0.4%) were newly-diagnosed with HIV infection. During the control phase, 29,925 eligible patients were included, 243 (0.8%) completed testing, and 4 (1.7%, 95% CI: 0.4%–4.2%) were newly-diagnosed with HIV infection. Total annualized costs for nontargeted screening were $148,997, whereas total annualized costs for diagnostic HIV testing were $31,355. The average costs per HIV diagnosis were $9,932 and $7,839, respectively. Nontargeted HIV screening identified 11 more HIV infections at an incremental cost of $10,693 per additional infection.

Conclusions

Compared to diagnostic testing, nontargeted HIV screening was more costly but identified more HIV infections. More effective and less costly testing strategies may be required to improve the identification of patients with undiagnosed HIV infection in the ED.     

Promoters maintain their relative activity levels under different growth conditions

Most genes change expression levels across conditions, but it is unclear which of these changes represents specific regulation and what determines their quantitative degree. Here, we accurately measured activities of ～900 S. cerevisiae and ～1800 E. coli promoters using fluorescent reporters. We show that in both organisms 60–90% of promoters change their expression between conditions by a constant global scaling factor that depends only on the conditions and not on the promoter's identity. Quantifying such global effects allows precise characterization of specific regulation—promoters deviating from the global scale line. These are organized into few functionally related groups that also adhere to scale lines and preserve their relative activities across conditions. Thus, only several scaling factors suffice to accurately describe genome‐wide expression profiles across conditions. We present a parameter‐free passive resource allocation model that quantitatively accounts for the global scaling factors. It suggests that many changes in expression across conditions result from global effects and not specific regulation, and provides means for quantitative interpretation of expression profiles.     

Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf‐footed cactus bug,Narnia femorata

The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf‐footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium‐quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high‐quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection.     

New Technologies to Prolong Life-time of Peptide and Protein Drugs In vivo

Most peptide and protein drugs are short-lived species in vivo with a circulatory half-life of several minutes. This is particularly valid for non-glycosylated proteins with a molecular mass of less than 50 kDa. Since peptide/protein drugs are not absorbed orally, prolonged maintenance of therapeutically active drugs in the circulatory system is of primary clinical importance. Another major obstacle of injected polypeptide drugs is the elevated concentration of 100–1000 times above the therapeutical level that may be present in the circulatory system shortly after administration. Such overdosing may lead to undesirable side effects such as over-stimulation or down-regulation of receptor sites. In this review we describe two new strategies that overcome these two problems of systemically injected peptide/protein drugs. The first strategy includes Fmoc and FMS derivatization of peptides, proteins and low molecular-weight drugs, converting them to inactive prodrugs that undergo reactivation with desirable pharmacokinetic patterns in body fluids. Based on this Fmoc/FMS-technology, we have developed a second strategy, reversible pegylation. Inactive pegylated peptide/protein drugs release the native active parental molecule at slow rates, and in homogeneous fashion under physiological conditions, thus facilitating prolonged therapeutic effects, following a single administration.     

Impact of apolipoprotein A1- or lecithin:cholesterol acyltransferase-deficiency on white adipose tissue metabolic activity and glucose homeostasis in mice

High density lipoprotein (HDL) has attracted the attention of biomedical community due to its well-documented role in atheroprotection. HDL has also been recently implicated in the regulation of islets of Langerhans secretory function and in the etiology of peripheral insulin sensitivity. Indeed, data from numerous studies strongly indicate that the functions of pancreatic β-cells, skeletal muscles and adipose tissue could benefit from improved HDL functionality. To better understand how changes in HDL structure may affect diet-induced obesity and type 2 diabetes we aimed at investigating the impact of Apoa1 or Lcat deficiency, two key proteins of peripheral HDL metabolic pathway, on these pathological conditions in mouse models. We report that universal deletion of apoa1 or lcat expression in mice fed western-type diet results in increased sensitivity to body-weight gain compared to control C57BL/6 group. These changes in mouse genome correlate with discrete effects on white adipose tissue (WAT) metabolic activation and plasma glucose homeostasis. Apoa1-deficiency results in reduced WAT mitochondrial non-shivering thermogenesis. Lcat-deficiency causes a concerted reduction in both WAT oxidative phosphorylation and non-shivering thermogenesis, rendering lcat^?/? mice the most sensitive to weight gain out of the three strains tested, followed by apoa1^?/? mice. Nevertheless, only apoa1^?/? mice show disturbed plasma glucose homeostasis due to dysfunctional glucose-stimulated insulin secretion in pancreatic β-islets and insulin resistant skeletal muscles. Our analyses show that both apoa1^?/? and lcat^?/? mice fed high-fat diet have no measurable Apoa1 levels in their plasma, suggesting no direct involvement of Apoa1 in the observed phenotypic differences among groups.