Expression of the entire polyhydroxybutyrate operon of <Emphasis Type="Italic">Ralstonia eutropha</Emphasis> in plants

Background

Previously we demonstrated that an entire bacterial operon (the PRN operon) is expressible in plants when driven by the Tomato -yellow-leaf-curl-virus (TYLCV) -derived universal vector IL-60.Petroleum-derived plastics are not degradable, and are therefore harmful to the environment. Fermentation of bacteria carrying operons for polyhydroxyalkanoates (PHAs) produces degradable bioplastics which are environmentally friendly. However, bacterial production of bioplastics is not cost-effective, and attention is turning to their production in plants. Such “green” plastics would be less expensive and environmentally friendly. Hence, attempts are being made to substitute petroleum-derived plastics with “green” plastics. However, transformation of plants with genes of operons producing bioplastics has deleterious effects. Transformation of plastids does not cause deleterious effects, however it is a complicated procedures.

Results

We have developed another TYLCV-based vector (SE100) and show that yet another bacterial operon (the phaCAB operon) when driven by SE100 is also expressed in plants. We employed the combination of SE100 and the phaCAB operon to drive the operon to the plastids and produce in plants a biodegradable plastic [polyhydroxybutyrate (PHB)].Here we indicate that the bacterial operon (phaCAB), when driven by the newly developed universal plant vector SE100 is directed to chloroplasts and produces in plants PHB, a leading PHA. The PHB-producing plants circumvent the need for complicated technical procedures.

Conclusion

The viral vector system SE100 facilitated the production of the bio-plastic poly-3-hydroxybutyrate. This was achieved by using the full pha-CAB operon indicating that TYLCV based system can transcribe and translate genes from bacterial operons controlled by a single cis element. Our data hints to the participation of the chloroplasts in these processes.

     

Feeding and survival of Culicoides sonorensis on cattle treated with permethrin or pirimiphos-methyl

The persistence of permethrin (5% a.i.) and pirimiphos-methyl (27% a.i.), applied to the dorsum of calves in the field against Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), was estimated using a hair-blood-feeding bioassay in the laboratory. Hair clippings were taken before treatment and 3, 7, 14, 21, 28, 42 and 56 days after treatment from the dorsum, side and belly of treated and control calves. Laboratory-reared insects were allowed to feed through thin hair layers and a parafilm membrane on sheep blood warmed using a water-jacketed feeder. Some intoxication after exposure to hair was noted up to 28 days after treatment with permethrin and up to 14 days after treatment with pirimiphos-methyl. Hair from the dorsum caused more intoxication for a longer period than hair from other body regions. Permethrin and pirimiphos-methyl applied to the back did not significantly reduce overall engorgement (body regions pooled) after treatment. Permethrin residues on hair remained far higher on the back than other body regions and were related to insect intoxication and reduction in engorgement in the laboratory. Residues on belly hair never exceeded 12p.p.m. and did not result in significantly reduced feeding at any time. Engorged insects that exhibited sublethal intoxication from feeding through permethrin-treated hair did recover and matured numbers of eggs comparable to controls. Field trials using treated and control calves and enclosure nets showed that dorsal applications of 5% permethrin were not effective in reducing engorgement, despite some intoxication. Vacuum samples from a calf showed that C. sonorensis fed primarily on the belly. A 0.2% permethrin application on the belly (250 ml) did result in > 80% reduction of C. sonorensis in the enclosure nets at 3 and 7 days after treatment, but activity had subsided by 10 days after treatment. The utility of insecticidal treatments for suppression of this vector is discussed.     

Using intense pulsed light for cosmetic purposes: our experience

The authors' experience using intense pulsed light for skin rejuvenation is summarized and analyzed with regard to its efficacy, safety, and complications. Rejuvenation using intense pulsed light was performed on 59 patients over a 6-month period (January of 2002 to July of 2002); these patients served as the study group. The areas treated were the face, neck, chest, hands, and legs. The parameters used during the procedure, patient satisfaction, and complications are described. Ninety-five percent of the patients included in the study had one or two sessions. Good to very good results were reported by 93.1 percent. Most patients had minor side effects and only three patients (5 percent) experienced complications (hyperpigmentation or scars). Intense pulsed light is an effective and safe method for skin rejuvenation. Its efficacy is mainly manifested by eliminating senile pigmentation and telangiectasias and a achieving a younger and fresher appearance of the skin. Although in the literature intense pulsed light skin rejuvenation is mainly reported for the face, the authors have obtained good results by using it for other areas of the body. The majority of the patients were satisfied. The authors conclude that intense pulsed light skin rejuvenation is a safe and effective method for facial and nonfacial rejuvenation.     

The effect of alpha2-adrenergic receptors on cutaneous water evaporation in the rock pigeon (Columba livia)

The role of beta-adrenergic receptors in regulating cutaneous water evaporation (CWE) in the rock pigeon (Columba livia) is well documented. Here, we studied the involvement of the alpha2-adrenergic receptors in this cooling mechanism of the heat-acclimated (HAc) pigeon. Systemic alpha2-adrenergic activation [clonidine, 50 microg kg(-1), intramuscular (i.m.)] was found to increase CWE in heat-acclimated pigeons at an ambient temperature (T(a)) of 25 degrees C. Subcutaneous administration of the drug had no significant effect. Preinjection of an alpha2-adrenergic antagonist (yohimbine, 10 mg kg(-1), i.m.) completely prevented clonidine-induced CWE and attenuated propranolol-induced CWE by 53%. Pretreatment with a beta-adrenergic agonist (isoproterenol, 4 mg kg(-1), i.m.) abolished the effect of clonidine. None of the above treatments was found to elicit significant CWE in nonacclimated (NAc) pigeons. These findings, in addition to previously reported data, indicate a complex regulatory pathway of CWE in the heat-acclimated pigeon consisting of alpha2- and beta2-adrenergic receptors. The possible hierarchical pattern of these receptors is discussed.     

Epidemiological interpretation of antibiotic resistance studies - what are we missing?

Antimicrobial resistance is an emerging public-health threat. Studies of the relationship between antibiotic use and resistance, as well as surveillance programmes, examine changes in the proportion of isolates that are resistant. Although proportions are helpful to the clinician prescribing empirical therapy, proportion-based analyses can be misleading to the public-health professional as they can yield biased estimates. Proportions do not adequately reflect the burden of resistance, a measure often of interest in public health. A more appropriate measure of this burden is the rate of isolation of resistant organisms, that is, the absolute number of resistant isolates in a population over time.     

Phylogenetic status and matrilineal structure of the biting midge, Culicoides imicola, in Portugal, Rhodes and Israel

The biting midge Culicoides imicola Kieffer (Diptera: Ceratopogonidae) is the most important Old World vector of African horse sickness (AHS) and bluetongue (BT). Recent increases of BT incidence in the Mediterranean basin are attributed to its increased abundance and distribution. The phylogenetic status and genetic structure of C. imicola in this region are unknown, despite the importance of these aspects for BT epidemiology in the North American BT vector. In this study, analyses of partial mitochondrial cytochrome oxidase subunit I gene (COI) sequences were used to infer phylogenetic relationships among 50 C. imicola from Portugal, Rhodes, Israel, and South Africa and four other species of the Imicola Complex from southern Africa, and to estimate levels of matrilineal subdivision in C. imicola between Portugal and Israel. Eleven haplotypes were detected in C. imicola, and these formed one well-supported clade in maximum likelihood and Bayesian trees implying that the C. imicola samples comprise one phylogenetic species. Molecular variance was distributed mainly between Portugal and Israel, with no haplotypes shared between these countries, suggesting that female-mediated gene flow at this scale has been either limited or non-existent. Our results provide phylogenetic evidence that C. imicola in the study areas are potentially competent AHS and BT vectors. The geographical structure of the C. imicola COI haplotypes was concordant with that of BT virus serotypes in recent BT outbreaks in the Mediterranean basin, suggesting that population subdivision in its vector can impose spatial constraints on BT virus transmission.     

Statins research unfinished saga: desirability versus feasibility

Drugs in the same class are generally thought to be therapeutically equivalent because of similar mechanisms of action (the so-called "class effect"). However, statins differ in multiple characteristics, including liver and renal metabolism, half-life, effects on several serum lipid components, bioavailability and potency. Some are fungal derivatives, and others are synthetic compounds. The percentage absorption of an oral dose, amount of protein binding, degree of renal excretion, hydrophilicity, and potency on a weight basis is variable. These differences may be even greater in diabetic patients, who may present diabetes-induced abnormalities in P450 isoforms and altered hepatic metabolic pathways. Thus, it is obvious that head-to-head comparisons between different statins are preferable than trial-to-trial comparisons. Such assessments are of utmost importance, especially in cases in which specific populations with a distinct lipid profile and altered metabolic pathways, like diabetics, are studied. It should be specially pinpointed that patients with metabolic syndrome and diabetes constitute also a special population regarding their atherogenic dyslipidemia, which is usually associated with low HDL-cholesterol, hypertriglyceridemia and predominance of small dense LDL-cholesterol. Therefore, these patients may benefit from fibrates or combined statin/fibrate treatment. This policy is not accomplished since in the real world things are more complex. Trials would require very large sample sizes and long-term follow-up to detect significant differences in myocardial infarction or death between two different statins. Moreover, the fact that new compounds are under several phases of research and development represents an additional drawback for performing the trials. Ideally, head-to-head trials regarding clinically important outcomes should be conducted for all drugs. Nonetheless, the desirability of performing such trials, which epitomize modern evidence-based medicine, is frequently superseded by the feasibility dictated by pragmatic and economic circumstances. In the latter case, in absence of solid systematic documentation of comparable health benefits and long-term safety, both researchers and practicing physicians should allude to the weight of scientific endorsement behind the arguments and seek for the possible strengths and weaknesses intrinsic to each specific study. In any case, conclusions based on surrogate endpoints cannot completely substitute head-to-head comparisons regarding patients' outcome.     

Versatile Utilization of Massive Bone Allografts in Orthopedic Surgery

The clinical use of massive bone allografts in orthopaedic surgery has become common practice in tumour operations and primary and revision total joint replacement. In certain special clinical situations associated with large bone loss, such as trauma, limb-length discrepancy repair or even infection, massive bone allografts can be successfully used. We present our treatment results of 47 patients who suffered from major bone loss due either to trauma, limb-length discrepancy repair, or infection. Our results (>2 years minimum follow-up to allow full-bone allograft incorporation) indicate that the use of massive bone allografts in these special and delicate medical conditions is feasible, and have good functional results.