Nature or nurture in low back pain? Results of a systematic review of studies based on twin samples

Twin studies are becoming popular to investigate risk factors for low back pain (LBP) because they consider the genetic factor and allow for more precise estimates of risks. We aimed to identify and summarize the results of studies based on twin samples investigating risk factors for LBP. The MEDLINE, CINAHL, LILACS, Web of Science and EMBASE databases were searched. Prospective and cross-sectional observational studies of LBP involving twins were included. The exposure factors could be genetics (heritability) or environmental such as smoking, alcohol consumption, body mass index and medical history. Pooling was attempted using an inverse variance weighting and fixed effects model. Twenty-seven studies were included. Estimates of heritability effects ranged from 21% to 67%. The genetic component was higher for more chronic and disabling LBP than acute and less disabling LBP. Smoking was significantly associated with LBP [pooled odds ratio (OR) = 3.0; 95% confidence interval (CI) 2.8-3.3] with a longitudinal and a cross-sectional study also identifying a dose-response relationship in people with chronic LBP. Obesity was associated with LBP (pooled OR = 1.9; 95% CI 1.6-2.2) with a cross-sectional study identifying a dose-response relationship. No association between alcohol consumption and LBP was identified. Co-morbidities such as asthma, diabetes and osteoarthritis were associated with LBP (pooled OR ranging from 1.6 to 4.2). The contribution of genetics to LBP appears to be dependent on the severity of the condition. Twin studies could be better used to explore possible causation paths between lifestyle factors, co-morbidities and LBP.

Changes in recruitment of transversus abdominis correlate with disability in people with chronic low back pain

OBJECTIVES

Although motor control exercises have been shown to be effective in the management of low back pain (LBP) the mechanism of action is unclear. The current study investigated the relationship between the ability to recruit transversus abdominis and clinical outcomes of participants in a clinical trial.

METHODS

Ultrasonography was used to assess the ability to recruit transversus abdominis in a nested design: a sample of 34 participants with chronic LBP was recruited from participants in a randomised controlled trial comparing the efficacy of motor control exercise, general exercise and spinal manipulative therapy. Perceived recovery, function, disability and pain were also assessed.

RESULTS

Participants with chronic LBP receiving motor control exercise had a greater improvement in recruitment of transversus abdominis (7.8%) than participants receiving general exercise (4.9% reduction) or spinal manipulative therapy (3.7% reduction). The effect of motor control exercise on pain reduction was greater in participants who had a poor ability to recruit transversus abdominis at baseline. There was a significant, moderate correlation between improved recruitment of transversus abdominis and a reduction in disability (r = -0.35; 95% CI 0.02 to 0.62).

CONCLUSION

These data provide some support for the hypothesised mechanism of action of motor control exercise and suggest that the treatment may be more effective in those with a poor ability to recruit transversus abdominis.

Self-reported moderate-to-vigorous leisure time physical activity predicts less pain and disability over 12 months in chronic and persistent low back pain

BACKGROUND

Physical deconditioning in combination with societal and emotional factors has been hypothesized to compromise complete recovery from low back pain (LBP). However, there is a lack of longitudinal studies designed to specifically investigate physical activity as an independent prognostic factor. We conducted a prognostic study to investigate whether levels of leisure time physical activity are independently associated with clinical outcomes in people seeking care for chronic and persistent LBP.

METHODS

A total of 815 consecutive patients presenting with LBP to an outpatient spine centre in secondary care were recruited. Separate multivariate linear regression analyses were performed to investigate whether levels of leisure time physical activity (i.e., sedentary, light and moderate-to-vigorous leisure time physical activity levels) predict pain and disability at 12-month follow-up, after adjusting for age, pain, episode duration, disability, neurological symptoms, depression and fear of movement.

RESULTS

Final models showed evidence of an association between baseline physical activity and 12-month outcomes (p < 0.001). In both models, the moderate-to-vigorous physical activity group reported less pain and disability compared with the sedentary group.

CONCLUSIONS

Our findings suggest that physical activity levels may have a role in the prognosis of LBP. Specific domains of physical activity warrant further investigation to better understand this association.

Isolation of Besnoitia besnoiti from infected cattle in Portugal

Besnoitia besnoiti, an obligate intracellular protozoan parasite belonging to the phylum apicomplexa, is the causative agent of bovine besnoitiosis. Besnoitiosis is responsible for significant losses in the cattle industry of Africa and Mediterranean countries due to the high morbidity rate, abortion and infertility in males. The acute stage of disease is associated with the proliferative forms (tachyzoites) and is characterized by fever, whimpery, general weakness and swelling of the superficial lymph nodes. During the following chronic stage, a huge number of cysts are formed mainly in the subcutaneous tissues. This process is non-reversible, and chronic besnoitiosis is characterized by hyper-sclerodermia, hyperkeratosis, alopecia and, in bulls, atrophy, sclerosis and focal necrosis that cause irreversible lesions in the testis. In this paper we report on the identification of large cysts in the skin of a cow and a bull in Portugal, which presented loss of hair and enlargement and pachydermis all over the body. The observation of a two-layered cyst wall within the host cell, the encapsulation of the host cell by a large outer cyst wall, and the subcutaneous localization of the cysts within the host, were characteristic for B. besnoiti. The parasites were isolated from the infected animals and successfully propagated in Vero cells without prior passages in laboratory animals. Morphological characterization of B. besnoiti tachyzoites and the amplification of the 149 bp segment from the internal transcribed spacer 1 (ITS1), aided with specific primers, confirmed the identification of B. besnoiti.

Effects of low-level laser therapy on wound healing

OBJECTIVE: To gather and clarify the actual effects of low-level laser therapy on wound healing and its most effective ways of application in human and veterinary medicine.METHODS: We searched original articles published in journals between the years 2000 and 2011, in Spanish, English, French and Portuguese languages, belonging to the following databases: Lilacs, Medline, PubMed and Bireme; Tey should contain the methodological description of the experimental design and parameters used.RESULTS: doses ranging from 3 to 6 J/cm2 appear to be more effective and doses 10 above J/cm2 are associated with deleterious effects. The wavelengths ranging from 632.8 to 1000 nm remain as those that provide more satisfactory results in the wound healing process.CONCLUSION: Low-level laser can be safely applied to accelerate the resolution of cutaneous wounds, although this fact is closely related to the election of parameters such as dose, time of exposure and wavelength.

Effect of applying different "levels of evidence" criteria on conclusions of Cochrane reviews of interventions for low back pain

The objective of this study was to examine the consistency of conclusions of Cochrane systematic reviews when different criteria are used to determine levels of evidence. We reanalyzed the data in six Cochrane reviews of conservative treatment of low back pain by applying three additional sets of "levels of evidence" criteria. Overall agreement between the conclusions attained with the different levels of evidence criteria was only "fair" (multirater kappa coefficient 0.33; 95% CI 0.28 to 0.38). For example, the four sets of levels of evidence criteria produced four conclusions on the efficacy of back school: "strong evidence that back schools are effective," "weak evidence," "limited evidence," and "no evidence." Pairwise agreement between the four pooling systems ranged from slight to substantial (kappas ranging from 0.10 to 0.80). Different rules for determining levels of evidence in systematic reviews produce markedly different conclusions on treatment efficacy. Crown

Susceptibility to ankylosing spondylitis is independent of the Bw4 and Bw6 epitopes of HLA-B27 alleles

We have characterized HLA-B27 alleles in a sample of the population from the Azores (n=46) with the aim of investigating the contribution of different subtypes to ankylosing spondylitis (AS). The study was carried out using PCR-SSOP and in some samples genomic sequencing was conducted. Some significant new finding have arisen from this study. First, B*2705,B*2702,B*2703,B*2707 and B*2708 alleles were found to be represented in this population. The polymorphism of B27 alleles found in a sample of the population from the Azores is higher than the Caucasian groups described. B*2703 and B*2707 have not previously been described to be represented in Caucasians and this could indicate admixtures with different populations of the world. In addition, the B*2708 allele was found to be associated with AS in a large family from the Azores. This association has not been previously reported in either ethnic group and needs to be confirmed in other population studies. This is of considerable interest since has only been described as a rare subtype underrepresented in the British population and has not been previously found to be associated with AS. B*2708 carries the sequence specifying the Bw6 epitope in contrast to most B27 alleles which carry a Bw4 sequence. Differences in this region (residues 77-83) can alter the F-pocket and affect T-cell recognition. The importance that these molecular changes can play in the pathogenesis of AS is discussed.

Toxic activities of venoms from nine Bothrops species and their correlation with lethality and necrosis

The comparison of seven toxic activities contained in venoms from nine different species of Bothrops and the correlation of each activity with lethality and necrosis was the subject of this study. The haemorrhagic, coagulant, necrotizing, myotoxic, proteolytic and phospholipase activities were not equally distributed among the venoms studied except for the oedema-inducing activity which was almost equally distributed among them. The correlation coefficient was estimated for each activity in relation to lethality and necrosis induced by the venom. Lethality was significantly related to haemorrhagic and oedema-inducing activities, whereas the necrotizing activity showed significant correlation with phospholipase and coagulant activities. Proteolytic activity presented a significant inverse correlation with lethality.

Spinal cord protection in descending thoracic and thoracoabdominal aortic aneurysm repair

During aneurysm repair of the descending thoracic or thoracoabdominal aorta, the likelihood of neurological complications increases greatly after only 30 minutes of spinal cord ischemia. However, the manifestation of paraplegia or paraparesis relates not only to aortic cross-clamping time, but to multiple factors that may include aortic dissection, previous aortic surgery, advanced age, preoperative renal insufficiency, rupture, and most significantly, aneurysm extent. At greatest risk is the patient with type II thoracoabdominal aortic aneurysm. For this patient the simple cross-clamp technique, which uses no protective surgical adjuncts, heightens the threat of neurological deficit. With the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, the probability of neurological deficit is appreciably lowered.

Neutralizing human anti crotoxin scFv isolated from a nonimmunized phage library

Combinatorial phage display technology offers a new possibility for making human antibodies which could be used in immune therapy. We explored the use of this technology to make human scFvs specific for crotoxin, the main toxic component of the venom of the South-American rattlesnake Crotalus durissus terrificus. Crotoxin, a phospholipase A2 neurotoxin constituted by the association of two subunits, exerts its lethal action by blocking neuromuscular transmission. This is the first report of human anticrotoxin scFvs (scFv 1, scFv 6 and scFv 8) isolated from a naive library of more than 1010 scFv clones with in vivo neutralizing activity. Nevertheless, differences are observed at the level of biological and immunological effects. Only scFv 8 is able to reduce the myotoxicity induced by crotoxin and scFv 1 is capable of altering the in vitro enzymatic activity of this toxin. All three scFvs recognize a region of one subunit located at the junction with the other one. Moreover these scFvs share strong amino acid homologies at the level of either the heavy or the light chain. Taken together, our results suggest that the use of human anticrotoxin scFvs may lead to a new and less aggressive passive immune therapy against poisoning by the venom of Crotalus durissus terrificus.

Neutralization of different activities of venoms from nine species of Bothrops snakes by Bothrops jararaca antivenom

Antivenoms are the usual treatment in cases of systemic envenoming by Bothrops snakes. However, the neutralization of each venom component by the antivenom is not well established. Bothrops jararaca antivenom, produced in rabbits, recognizes the venoms of nine different Bothrops species with high ELISA antibody titres. Western blot analysis showed that almost all antigens present on both homologous and heterologous venoms are recognized. Neutralization tests were performed using whole antivenom or its IgG fraction. The antivenom was able to neutralize the haemorrhagic, coagulant and necrotizing activities of the heterologous venoms in the same antivenom/venom proportion as for the homologous venom. Myotoxic activity was only partially neutralized. Neutralization of the proteolytic activity of heterologous venoms required higher amounts of antivenom than for the homologous venom. Phospholipase and oedema-inducing activities were completely neutralized only in the homologous system.

New diketopiperazines from the sponge Dysidea chlorea

Twelve new polychlorinated diketopiperazines (7-18), along with six known ones (1-6) and a known sterol (19), were isolated from the sponge Dysidea chlorea, collected from Yap, Federated States of Micronesia. The structures of dysamides I-T (7-18) were elucidated by spectroscopic methods, and one (8) was confirmed by chemical conversion. The stereochemistry of the dysamides is discussed.

The influence of weather on the risk of pain exacerbation in patients with knee osteoarthritis - a case-crossover study

OBJECTIVE

To quantify the risk of knee pain exacerbation associated with temperature, relative humidity, air pressure and precipitation in persons with knee osteoarthritis.

METHOD

A web-based case-crossover study was conducted. Participants with a diagnosis of symptomatic, radiographic knee osteoarthritis were measured at baseline and followed for 3 months. Participants were instructed to log on to the study website if they perceived experiencing knee pain exacerbation (hazard period). Pain exacerbation was defined as an increase of ≥2 on a 0-10 numeric rating scale (NRS) from the participant's mildest pain reported at baseline. A time-stratified case-crossover study was conducted to anchor the corresponding hazard date to four control periods within a particular 35-day interval. Data on maximum and minimum temperature (°C), relative humidity (%), barometric pressure (hPa) and precipitation (mm) were obtained for the hazard and control periods from the publicly available meteorological database of the Australian Bureau of Meteorology. The associations were assessed using conditional logistic regression.

RESULTS

Of the 345 participants recruited, 171 participants (women: 64%, mean age: 62 years, mean BMI: 30.2 kg/m²) experienced at least one episode of pain exacerbation, yielding 1,425 observations included in the analyses. There was no apparent association between temperature, relative humidity, air pressure or precipitation and risk of knee pain exacerbation.

CONCLUSION

Despite anecdotal reports from patients, change in weather factors does not appear to influence the risk of pain exacerbation in persons with knee osteoarthritis. Additional studies should quantify the association of weather and risk of pain exacerbation in regions with more extreme weather conditions.

Patients with sciatica still experience pain and disability 5 years after surgery: A systematic review with meta-analysis of cohort studies

BACKGROUND AND OBJECTIVE

The clinical course of patients with sciatica is believed to be favourable, but there is conflicting evidence on the postoperative course of this condition. We aimed to investigate the clinical course of sciatica following surgery.

DATABASES AND DATA TREATMENT

An electronic search was conducted on MEDLINE, EMBASE and CINAHL from inception to April 2015. We screened for prospective cohort studies investigating pain or disability outcomes for patients with sciatica treated surgically. Fractional polynomial regression analysis was used to generate pooled means and 95% confidence intervals (CI) of pain and disability up to 5 years after surgery. Estimates of pain and disability (converted to a 0-100 scale) were plotted over time, from inception to last available follow-up time.

RESULTS

Forty records (39 cohort studies) were included with a total of 13,883 patients with sciatica. Before surgery, the pooled mean leg pain score was 75.2 (95% CI 68.1-82.4) which reduced to 15.3 (95% CI 8.5-22.1) at 3 months. Patients were never fully recovered in the long-term and pain increased to 21.0 (95% CI 12.5-29.5) at 5 years. The pooled mean disability score before surgery was 55.1 (95% CI 52.3-58.0) and this decreased to 15.5 (95% CI 13.3-17.6) at 3 months, and further reduced to 13.1 (95% CI 10.6-15.5) at 5 years.

CONCLUSIONS

Although surgery is followed by a rapid decrease in pain and disability by 3 months, patients still experience mild to moderate pain and disability 5 years after surgery. WHAT DOES THIS REVIEW ADD?: This review provides a quantitative summary of the postoperative course of patients with sciatica. Patients with sciatica experienced a rapid reduction in pain and disability in the first 3 months, but still had mild to moderate symptoms 5 years after surgery. Although no significant differences were found, microdiscectomy showed larger improvements compared to other surgical techniques.

Brain and ocular metastases from a transmissible venereal tumour in a dog

A five-year-old crossbred dog was referred with rapidly growing masses over its penis and right popliteal lymph node. The dog had severe blepharospasm, congestion of episcleral vessels and rubeosis iridis of the left eye. A presumptive diagnosis of transmissible venereal tumour (TVT) and iridocyclitis was made based on the results of fine needle aspiration. Chemotherapy with vincristine and prednisolone was initiated and after four months the dog made a complete recovery. However, the dog subsequently relapsed, showing miosis, blepharospasm and a well defined mass within the anterior chamber of the left eye. In addition, the dog exhibited generalised 'grand mal' type seizures. Computed tomographic (CT) examination of the brain revealed two distinct masses in the left frontal lobe. Because of the poor prognosis, the owners elected to have the dog euthanased. On histopathology, metastases of TVT in the left eye and left cerebral hemisphere were found, showing no specific staining for CD3, immunoglobulin (Ig) G, IgM and lambda light chains. It was therefore concluded that the tumour growth was progressive, and that there was an absence of local humoral immune response against TVT in this case.

Frequent analytical/experimental problems in lipase-mediated synthesis in solvent-free systems and how to avoid them

Compared with chemical catalysis, enzymatic catalysis is a relatively new topic. Experimental work involving lipases deserves careful attention and accurate procedures still need to be implemented. A rapid but careful survey of published data immediately demonstrates that experiments performed under similar conditions with similar reagents have led to very different results. The aim of this work is to point out the importance of accurate and systematic procedures in order to ensure the reproducibility of experimental data. We strongly believe that different results found by different labs are due to problems detected in the procedures used. Quantification of the immobilisation efficiency of lipase on several supports through UV/visible methods and sampling methods used to obtain correct enzymatic activity values are specifically analysed. After a brief review which demonstrates the big discrepancies found in the literature, original data from Candida rugosa lipase adsorption on polypropylene powder and its use in the solvent-free synthesis of ethyl oleate are introduced in order to exemplify the difficulties found in these kinds of systems. Several procedures described in the literature are assayed and the accuracy of the results obtained is carefully analysed. The aim of the whole analysis performed is that it would be useful for any powdered solid to be used as a support for a lipase in a solvent-free system for any synthesis reaction, especially for those involving a volatile reagent. Throughout this contribution, special emphasis is placed on how catalytic reaction results using enzymes (free and immobilised) are reported so as to allow comparison between published data, something which is usually difficult since very different units are used and often complementary data are not included.

Smallest worthwhile effect of exercise programs to prevent falls among older people: estimates from benefit-harm trade-off and discrete choice methods

BACKGROUND

the smallest worthwhile effect (SWE) of an intervention is the smallest treatment effect that justifies the costs, risks and inconveniences associated with that health intervention.

OBJECTIVE

to estimate the SWE of exercise programs designed to prevent falls among older people and to compare estimates derived by two methodological approaches.

STUDY DESIGN AND SETTING

discrete choice experiment (n = 220) and benefit-harm trade-off (subsample n = 66) methods were used.

PARTICIPANTS

community-dwelling older people who reported a past fall or a mobility limitation answered online or face-to-face questionnaires.

RESULTS

a substantial proportion of participants (82% in the discrete choice experiment and 50% in the benefit-harm trade-off study) did not consider that participation in the proposed exercise programs would be worthwhile, even if it reduced their risk of falling to 0%. Among remaining participants, the average SWE of participation in an exercise program was an absolute reduction in the risk of falling of 35% (standard deviation [SD] = 13) in the discrete choice experiment and 16% (SD = 11) in the benefit-harm trade-off study.

CONCLUSIONS

many participants did not consider the hypothetical falls' risk reduction of the proposed exercise programs to be worth the associated costs and inconveniences. Greater community awareness of the fall prevention effects of exercise for older people is required.

Synthesis and antimycobacterial evaluation of N'-(E)-heteroaromaticpyrazine-2-carbohydrazide derivatives

A series of nine N'-(E)-heteroaromatic-pyrazine-2-carbohydrazide derivatives (5a-f and 6a-c) have been synthesized and evaluated against M. tuberculosis ATCC 27294 using the micro plate Alamar Blue assay (MABA), being the activities expressed as the minimum inhibitory concentration (MIC) in µg/ml. Compounds 5a and 5f exhibited potent activities (3.12 and 50µg/mL, respectively) when compared to the first line drug pyrazinamide (MIC>100 µg/mL). Afterwards, these compounds were evaluated for their cell viabilities in non-infected and infected macrophages with Mycobaterium bovis Bacillus Calmette-Guerin (BCG) and 5f was not cytotoxic to host cells in the effective concentration to inhibit the growth of M. tuberculosis.

Do older adults with chronic low back pain differ from younger adults in regards to baseline characteristics and prognosis?

BACKGROUND

Low back pain (LBP) in older adults is poorly understood because the vast majority of the LBP research has focused on the working aged population. The aim of this study was to compare older adults consulting with chronic LBP to middle aged and young adults consulting with chronic LBP, in terms of their baseline characteristics, and pain and disability outcomes over 1 year.

METHODS

Data were systematically collected as part of routine care in a secondary care spine clinic. At initial presentation patients answered a self-report questionnaire and underwent a physical examination. Patients older than 65 were classified as older adults and compared to middle aged (45-65 years old) and younger adults (17-44 years old) for 10 baseline characteristics. Pain intensity and disability were collected at 6 and 12 month follow-ups and compared between age groups.

RESULTS

A total of 14,479 participants were included in the study. Of these 3087 (21%) patients were older adults, 6071 (42%) were middle aged and 5321 (37%) were young adults. At presentation older adults were statistically different to the middle aged and younger adults for most characteristics measured (e.g. less intense back pain, more leg pain and more depression); however, the differences were small. The change in pain and disability over 12 months did not differ between age groups.

CONCLUSIONS

This study found small baseline differences in older people with chronic LBP compared to middle aged and younger adults. There were no associations between age groups and the clinical course.

SIGNIFICANCE

Small baseline differences exist in older people with chronic low back pain compared to middle aged and younger adults referred to secondary care for chronic low back pain. Older adults present with slightly less intense low back pain but slightly more intense leg pain. Changes in pain intensity and disability over a 12 month period were similar across all age groups.

The medial preoptic area modulates the increase in plasma glucose and free fatty acid mobilization induced by acute cold exposure

The effect of cold exposure (0 degrees C, 1 h) on free fatty acid (FFA) mobilization and plasma glucose was studied in freely moving male rats injected with adrenergic blockers (phentolamine or propranolol) into the medial preoptic area (MPOA). The rats were implanted with chronic jugular catheters for blood sampling and with unilateral intracerebral cannulas placed just above the MPOA. Blood samples were taken 2 min before and 10, 20, 40 and 60 min after cold exposure. After cold exposure plasma glucose and plasma FFA levels rose rapidly, reaching a peak at 20 min post-stimulus. Previous administration of phentolamine (50 nmol), but not propranolol (100 nmol), into the MPOA blocked the glycemic response to cold exposure. On the other hand, previous administration of propranolol, but not phentolamine, into the MPOA blocked the increased FFA mobilization in response to cold exposure. On the basis of these results, we propose that MPOA alpha-adrenergic synapses relay impulses activating the sympathetic outflow expressed by neurally mediated hyperglycemia, and beta-adrenergic synapses relay impulses activating the sympathetic outflow to the adipose tissue, increasing FFA acid mobilization.

Establishment of local wastewater-based surveillance programmes in response to the spread and infection of COVID-19 - case studies from South Africa, the Netherlands, Turkey and England

The COVID-19 pandemic has resulted in over 340 million infection cases (as of 21 January 2022) and more than 5.57 million deaths globally. In reaction, science, technology and innovation communities across the globe have organised themselves to contribute to national responses to COVID-19 disease. A significant contribution has been from the establishment of wastewater-based epidemiological (WBE) surveillance interventions and programmes for monitoring the spread of COVID-19 in at least 55 countries. Here, we examine and share experiences and lessons learnt in establishing such surveillance programmes. We use case studies to highlight testing methods and logistics considerations associated in scaling the implementing of such programmes in South Africa, the Netherlands, Turkey and England. The four countries were selected to represent different regions of the world and the perspective based on the considerable progress made in establishing and implementing their national WBE programmes. The selected countries also represent different climatic zones, economies, and development stages, which influence the implementation of national programmes of this nature and magnitude. In addition, the four countries' programmes offer good experiences and lessons learnt since they are systematic, and cover extensive areas, disseminate knowledge locally and internationally and partnered with authorities (government). The programmes also strengthened working relations and partnerships between and among local and global organisations. This paper shares these experiences and lessons to encourage others in the water and public health sectors on the benefits and value of WBE in tackling SARS-CoV-2 and related future circumstances.

Longithorols A and B, novel prenylated paracyclophane- and metacyclophane-type hydroquinones from the tunicate Aplidium longithorax

The tunicate Aplidium longithorax collected from Palau contained two novel prenylated paracyclophane- and metacyclophane-type hydroquinones, longithorols A (1) and B (2), in addition to longithorones A-I. Longithorols A and B were very unstable and were therefore isolated as their more stable pentaacetate forms, 3 and 4, respectively. The structures of 3 and 4 were determined by spectral data, especially 2D NMR data.

Ethyl Oleate Synthesis Using Candida rugosa Lipase in a Solvent-Free System. Role of Hydrophobic Interactions

The solvent-free esterification reaction of a commercial oleic acid and ethanol was selected as the test reaction for Candida rugosa lipase immobilized on polypropylene (PP) at 318 K (initial molar ratio 1:1). Adding of water from 0 to 30 wt. % (in gram per gram of fatty acid x 100) and the pretreatment of Candida rugosa lipase with polyethylenglycol (PEG), octane, and acetone increases the conversion to ethyl esters. The role of hydrophobic interactions of the lipase with PP and PEG was studied using molecular mechanics (MM2) for calculation of steric energies and the parametrized model (PM3) for calculation of enthalpy changes upon interaction. The nonpolar lateral groups of amino acids interact strongly with PP, whereas polar groups interact more strongly with PEG. Both interactions stabilize the open, active conformation of the lipase from Candida rugosa. Activities ranged from 5 x 10(-5) to 2.0 x 10(-4) mol ethyl oleate/h/mg enzyme, depending on reaction conditions. Steric energy changes vary between +30 and -10 kcal/mol, whereas the enthalpy changes ranged from +10 to -10 kcal/mol.

Halisulfate 7, a new sesterterpene sulfate from a sponge, Coscinoderma sp

A new sesterterpene sulfate, halisulfate 7 (1), has been isolated from a Coscinoderma sp. of sponge collected at Yap, Federated States of Micronesia. The structure was determined from spectroscopic evidence.