Performance of a β-d-galactosidase hollow fibre reactor

β-d-Galactosidase was immobilized in a hollow fibre ultrafiltration module. The hydrolysis of 2-nitrophenyl β-d-galactopyranoside (ONPG) was significantly affected by enzyme loading, flow rate and substrate concentration. Pretreatment of hollow fibres with a protein was necessary to minimize enzyme inactivation. Residence time distribution studies indicated that the product of the reaction (ONP) was significantly adsorbed by the fibres, which resulted in the reactor taking 10–30 h to achieve steady-state. An equation based on Michaelis-Menten kinetics and a plug-flow model adequately described the performance of the reactor with regard to operating variables, even though some diffusion effects were observed.     

An analysis of extracellular single muscle fibre action potential field —Modelling results

The radial variability of extracellular single muscle fibre action potential (SFAP) field was studied on the basis of an SFAP theoretical model originally constructed by Rosenfalck (1969). Amplitude and time parameters of the SFAP as a function of the radial distance r10 mm from the fibre were described by simple mathematical expressions. The results obtained were compared with existing experimental data from different authors and discussed in detail.     

The morphology of single muscle fibre potentials – Part II: Experimental findings

Studies dealing with single fibre action potentials (SFAPs) have been more interested in obtaining quantitative data of certain parameters of the SFAP waveform than in the analysis of its morphologic features. The characterization of the SFAP morphology is highly valuable as it will allow to obtain information about in vivo intracellular action potentials (IAPs). However, the SFAP final portion is highly sensitive to distant electrical activity, as shown in Part I of this study. The present paper, Part II, is aimed at analysing the morphologies found in human SFAPs and deriving data of the associated IAPs. It was found that, for most SFAPs (97%), the declining negative phase starts decreasing steeply up to a certain point (slope-discontinuity point), from which it returns more slowly towards the baseline. This return may be further slowed down due to the contamination from distant potentials, but the slope-discontinuity point seems to be an intrinsic feature of human SFAPs. The third phase of SFAPs was, either absent (65%), or of rather small amplitude and prolonged duration. The slope-discontinuity point was apparent for the SFAPs of larger amplitude and vanished gradually as the SFAPs got smaller. Several lines of evidence strongly suggest that the spike duration of human IAPs should be about 1.0 ms.     

Reissner’s fibre supports the survival of chick cortical neurons in primary mixed cultures

Reissner's fibre, a thread-like structure present in the central canal of the spinal cord, is a product of the condensation of specific glycoproteins that are released by specialized ependymal cells into the cerebrospinal fluid. These secretory ependymocytes constitute the subcommissural organ, a circumventricular organ that lines the roof of the third ventricle of the brain. The subcommissural organ/Reissner's fibre complex is a permanent structure in the vertebrate central nervous system. The addition of bovine Reissner's fibre itself or of soluble material released by Reissner's fibre to primary mixed cultures of chick cerebral cortical cells markedly enhances neuronal survival. The responsive cells have been identified as neurons by labelling them with antibodies to neurofilament proteins. This neuronal survival effect is dose-dependent and does not require the presence of serum in the culture medium. Affinity-purified polyclonal antibodies raised against bovine Reissner's fibre partially block the effect of Reissner's fibre on neuronal survival. These results suggest that Reissner's fibre is involved in developmental processes of the central nervous system.     

Evidence of fibre hyperplasia in human skeletal muscles from healthy young men? A left-right comparison of the fibre number in whole anterior tibialis muscles

Cross-sections (thickness 10 microns) of whole autopsied left and right anterior tibialis muscles of seven young previously healthy right-handed men (mean age 23 years, range 18-32 years) were prepared for light-microscope enzyme histochemistry. Muscle cross-sectional area and total number of fibres, mean fibre size (indirectly determined) and proportion of the different fibre types (type 1 and type 2 on basis of myofibrillar adenosine triphosphatase characteristics), in each muscle cross-section were determined. The analysis showed that the cross-sectional area of the left muscle was significantly larger (P less than 0.05), and the total number of fibres was significantly higher (P less than 0.05), than for the corresponding right muscle. There was no significant difference for the mean fibre size or the proportion of the two fibre types. The results imply that long-term asymmetrical low-level daily demands on muscles of the left and the right lower leg in right-handed individuals provide enough stimuli to induce an enlargement of the muscles on the left side, and that this enlargement is due to an increase in the number of muscle fibres (fibre hyperplasia). Calculations based on the data also explain why the underlying process of hyperplasia is difficult, or even impossible, to detect in standard muscle biopsies.     

Are fibre supplements really necessary in diverticular disease of the colon? A controlled clinical trial.

Fifty-eight patients with uncomplicated diverticular disease of the colon took bran crispbread, ispaghula drink, and placebo for four months each in a randomised, cross-over, double-blind controlled trial. Assessments were made subjectively, using a monthly self-administered questionnaire, and objectively, by examining a seven-day stool collection at the end of each treatment period. In terms of a pain score, lower bowel symptom score (the pain score and sensation of incomplete emptying, straining, stool consistency, flatus, and aperients taken), and total symptom score (belching, nausea, vomiting, dyspepsia, and abdominal distension) fibre supplementation conferred no benefit. Symptoms of constipation, however, when assessed alone, were significantly relieved. Both fibre regimens produced the expected changes in stool weight, consistency, and frequency. It is concluded that dietary fibre supplements in the commonly used doses do no more than relieve constipation. Perhaps the impression that fibre helps diverticular disease is simply a manifestation of Western civilisation''s obsession with the need for regular frequent defecation.     

Structure–function relationships of four compression wood types: micromechanical properties at the tissue and fibre level

The mechanisms behind compressive stress generation in gymnosperms are not yet fully understood. Investigating the structure–function relationships at the tissue and cell level, however, can provide new insights. Severe compression wood of all species lacks a S3 layer, has a high microfibril angle in the S2 layer and a high lignin content. Additionally, special features like helical cavities or spiral thickenings appear, which are not well understood in terms of their mechanical relevance, but need to be examined with regard to evolutionary trends in compression wood development. Thin compression wood foils and isolated tracheids of four gymnosperm species [Ginkgo biloba L., Taxus baccata L., Juniperus virginiana L., Picea abies (L.) Karst.] were investigated. The tracheids were isolated mechanically by peeling them out of the solid wood using fine tweezers. In contrast to chemical macerations, the cell wall components remained in their original condition. Tensile properties of tissue foils and tracheids were measured in a microtensile apparatus under wet conditions. Our results clearly show an evolutionary trend to a much more flexible compression wood. An interpretation with respect to compressive stress generation is discussed.     

Laccase-catalysed protein–flavonoid conjugates for flax fibre modification

The introduction of flavonoid compounds into proteins can improve the natural properties of proteins, being promising products which essentially require antioxidant property. The oxidative conjugation of protein–flavonoids was processed by laccase catalysis resulting in the synthesis of biologically functional polymers. The new reaction products were detected in terms of sodium dodecyl sulfate polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionisation-time of flight mass spectra, showing a greater molecular weight formation. Their characterisations were further carried out in terms of UV–Vis spectroscopy, photon correlation spectroscopy, differential scanning calorimetry and Fourier transform infrared (FT-IR) spectroscopy analysis. In addition, their application of protein–flavonoid conjugates onto flax fibres was exploited to supplement a suitable microorganism environment of protein-possessed fibres. The anchoring of conjugates onto cationised fibres was successfully performed by ionic interaction with negatively charged proteins. The level of anchoring efficiency was quantified in terms of measuring colour strength (k/s) and fluorescence microscopy analysis. The conjugates onto fibres presented acceptable durability in terms of washing resistance and the surface became hydrophilic when α-casein–catechin was applied (lower contact angle 48°). By the anchoring of protein–flavonoid conjugates onto flax fibres, the final products with new colour generation and antioxidant activity (>93%) were obtained.     

Identification procedure in a model of single fibre action potential – Part II: Global approach and experimental results

The present paper describes a global procedure for estimating all the synthesis parameters that generate a single fibre action potential (SFAP) in the Dimitrov–Dimitrova (D–D) convolutional model. We call this inverse problem Identification Procedure, and it is presented in two parts, this paper being the second. The procedure incorporates the candidate pair (CP) method developed in Part I, which provides the values of radial distance r and fibre diameter d of the simulated SFAP that best matches a potential under study. The CP-method required prior knowledge of all the excitation parameters. However, since the Identification Procedure makes no assumption about the excitation, multiple combinations of the synthesis parameters result in very similar SFAPs whose shape is close the signal under study. Analysis of the possible combinations reveals that r and d can be modelled as two jointly Gaussian random variables. The interest of the Identification Procedure is that, for a certain SFAP, it provides estimates of r and d, along with estimates of different parameters that determine the IAP waveform. Moreover, the procedure is able to determine the degree of error that accompanies the estimation of r and d.     

Flax for oil or fibre? Morphometric analysis of flax seeds and new aspects of flax cultivation in Late Neolithic wetland settlements in southwest Germany

The transition from the early to the middle phase of the Late Neolithic (fourth–third millennium b.c.) is closely connected with the term “secondary products revolution”, which involves the adoption of animal traction and an increased production of rendered animal commodities such as wool and dairy products. Based on measurements of Linum usitatissimum L. (flax) seeds and their abundance in 32 wetland settlements in southwest Germany, we presume that the introduction of a new flax variety, maybe a better flax for fibre, and the intensification of flax cultivation were also a part of this process. The morphometric analysis shows that flax seed sizes in the early phase of the Late Neolithic (4000–3400 cal. b.c.) differ significantly from those of the middle and latest phase (3400–2400 cal. b.c.).     

Structure-based prediction of protein–protein interactions between GhWlim5 Domain1 and GhACTIN-1 proteins: a practical evidence with improved fibre strength

Cotton fibre quality is a multigenic trait. Genetic modification of different genes to achieve high quality fibre is difficult without knowing the mechanism lying behind genes interaction. Based on background knowledge an attempt to explore the potential structural interactions between Gossypium hirsutum Wlim5 domain1 and Gossypium hirsutum ACTIN-1 proteins was done in current study. Sequence features of the LIM domain1 of GhWlim5 protein were identified through multiple sequence alignment analysis, and a phylogenetic tree was built to identify evolutionary relationships between sequences. Conservation indicated the evolutionary importance of side chain residues and the presence of several aliphatic and/or bulky residues, which stabilize the protein core and facilitate packing of zinc fingers. The structures of GhWlim5 domain1 and GhACTIN-1 proteins were modelled and validated through computational methods. Validation of GhACTIN-1 and GhWlim5 domain1 structures indicated good structural quality with 99.7% and 100% of the favoured number of residues in allowed regions and Z-score, within the ranges of − 9.87 and − 4.17, respectively. Docking analysis indicated various possible modes of interaction between these two proteins with favourable binding affinities. Based on our strong binding interaction results between GhWlim5 domain1 and GhACTIN-1 proteins, we further investigated the role of over-expression of GhWlim5 by transformation in cotton plants under fibre specific promoter and transgenic plants displayed significant increases in fibre strength.

     

A comparative study on the graft copolymerization of acrylic acid onto rayon fibre by a ceric ion redox system and a γ-radiation method

Functionalization of rayon fibre has been carried out by grafting acrylic acid (AAC) both by a chemical method using a Ce⁴⁺-HNO₃ redox initiator and by a mutual irradiation (γ-rays) method. The reaction conditions affecting the grafting percentage have been optimized for both methods, and the results are compared. The maximum percentage of grafting (50%) by the chemical method was obtained utilizing 18.24 × 10⁻³ moles/L of ceric ammonium nitrate (CAN), 39.68 × 10⁻² moles/L of HNO₃, and 104.08 × 10⁻² moles/L of AAc in 20 mL of water at 45 °C for120 min. For the radiation method, the maximum grafting percentage (60%) was higher, and the product was obtained under milder reaction conditions using a lower concentration of AAc (69.38 × 10⁻² moles/L) in 10 mL of water at an optimum total dose of 0.932 kGy. Swelling studies showed higher swelling for the grafted rayon fibre in water (854.54%) as compared to the pristine fibre (407%), while dye uptake studies revealed poor uptake of the dye (crystal violet) by the grafted fibre in comparison with the pristine fibre. The graft copolymers were characterized by IR, TGA, and scanning electron micrographic methods. Grafted fibre, prepared by the radiation-induced method, showed better thermal behaviour. Comparison of the two methods revealed that the radiation method of grafting of acrylic acid onto rayon fibre is a better method of grafting in comparison with the chemical method.     

Are region-specific changes in fibre types attributable to nonuniform muscle hypertrophy by overloading?

Muscle fibre composition was compared among the proximal (25%), middle (50%) and distal (75%) regions of the muscle length to investigate whether compensatory overload by removal of synergists induces region-specific changes of fibre types in rat soleus and plantaris muscles. In addition, we evaluated fibre cross-sectional area in each region to examine whether fibre recruitment pattern against functional overload is nonuniform in different regions. Increases in muscle mass and fibre area confirmed a significant hypertrophic response in the overloaded soleus and plantaris muscles. Overloading increased the percentage of type I fibres in both muscles and that of type IIA fibres in the plantaris muscle, with the greater changes being found in the middle and distal regions. The percentage of type I fibres in the proximal region was higher than that of the other regions in the control soleus muscle. In the control plantaris muscle, the percentage of type I and IIA fibres in the middle region were higher than that of the proximal and distal regions. With regard to fibre size, type IIB fibre area of the middle and distal regions in the plantaris increased by 51% and 57%, respectively, with the greater changes than that of the proximal region (37%) after overloading. These findings suggest that compensatory overload promoted transformation of type II fibres into type I fibres in rat soleus and plantaris muscles, with the greater changes being found in the middle and distal regions of the plantaris muscle.     

Does adding fibre to a low energy,high carbohydrate,low fat diet confer any benefit to the management of newly diagnosed overweight type II diabetics?

The effect of supplementing a low energy (roughly 5·0 MJ), high carbohydrate (180 g), low fat (roughly 25 g) diet with 10-15 g of either cereal fibre or guar gum was investigated in 24 newly diagnosed overweight non-insulin-dependent (type II) diabetics. The patients were divided into three treatment groups: one received a low fibre control diet throughout the study period of 20 weeks and the other received two supplements of cereal fibre and guar gum in a crossover manner. The nutrient content of the diets was kept constant throughout. Though patients taking the low fibre diet showed a smaller reduction in fasting plasma glucose concentrations over the first eight weeks than patients taking a high fibre diet, this difference was not evident at the end of 20 weeks; reductions in weight and glycated haemoglobin values were similar for each dietary regimen throughout the trial.There was little evidence that supplementing a low energy, high carbohydrate diet with fibre confers any therapeutic benefit to type II diabetics and no evidence that taking fibre as viscous polysaccharides is any more beneficial to overweight diabetics than taking a similar fibre supplement as cereal. On the contrary, guar gum caused more abdominal discomfort and flatulence than the other diets.     

Meal replacements and fibre supplement as a strategy for weight loss. Proprietary PGX® meal replacement and PGX® fibre supplement in addition to a calorie-restricted diet to achieve weight loss in a clinical setting

Meal replacements and viscous soluble fibre represent safe and sustainable aids for weight loss. Our purpose was to determine if PGX® meal replacements and PGX^® fibre complex in combination with a calorie-restricted diet would aid in weight loss in a clinical setting. Fifty-two overweight and obese participants (49 women, 3 men; average age 47.1 years) with a mean body mass index (BMI) of 33.8 ± 6.4 kg/m² consumed 57 g of proprietary PGX® meal replacement product at breakfast and another 57 g at lunch for 12 weeks. In addition to the meal replacements, they were also asked to consume 5 g/day of PGX® fibre in the form of granules, powder or capsules together with 250 mlwater. A registered dietician recommended low-fat, low-glycaemic-index foods for snacks and the dinner menus such that each volunteer was consuming a total of 1200 kcal/day. All participants (n = 52) lost a significant amount of weight from baseline (?4.69 ± 3.73 kg), which was further reflected in the reductions in their waist (?7.11 ± 6.35 cm) and hip circumference (?5.59 ± 3.58 cm) over the 12-week study (p < 0.0001). BMI scores (n = 51) were reduced by 1.6 ± 1.4 kg/m². The use of PGX® meal replacements and PGX^® fibre along with a controlled dietary caloric intake is of benefit for short-term weight loss.     

Vesicular glutamate transporter 2 is expressed in different nerve fibre populations that selectively contact pulmonary neuroepithelial bodies

Pulmonary neuroepithelial body (NEB) receptors in rats receive at least four different nerve fibre populations. In addition to a spinal sensory innervation that contacts NEBs at their basal side, extensive vagal nodose sensory terminals and separate nitrergic and cholinergic nerve endings protrude between NEB cells. In the present study, antibodies against the vesicular glutamate transporter 2 (VGLUT2), a transmembrane protein responsible for loading glutamate into synaptic vesicles, were used to investigate whether some of the nerve terminals contacting NEBs in rat lungs might use glutamate as a neurotransmitter. VGLUT2 immunoreactivity (IR) was detected in extensive intraepithelial arborising nerve terminals that appeared to contact most of the NEBs. Multiple immunostaining showed VGLUT2 IR in the vagal nodose and spinal sensory nerve terminals contacting NEBs, and in another, most likely sensory, intraepithelial nerve fibre population, the origin and further characteristics of which remain to be elucidated. At least part of the VGLUT2-immunoreactive nerve fibres that contact NEBs were shown to be myelinated. The expression of VGLUT2 indicates that glutamate is stored and released as a neurotransmitter in terminals of several pulmonary (sensory) nerve fibre populations that selectively relate to the complex NEB receptors. The present study strongly suggests an involvement of glutamatergic mechanisms in the peripheral transduction of sensory stimuli from the lungs, via the release of glutamate from nerve terminals, thereby modulating the activity of NEB receptor cells or the excitability of afferent nerves.     

Jute — world’s foremost bast fibre,II. Technology,marketing, production and utilization

Jute fibre is the world’s principal material in manufacturin? coarse textile for conversion into sackin? and canvas. It enters also into the production of upholstery, ru?s, carpets and roofin? fabrics. Secondary products are food from its tender shoots, medicines from its dried leaves, fuel and paper from its stems, and oil from its seeds.     

Lpaatδ/Agpat4 deficiency impairs maximal force contractility in soleus and alters fibre type in extensor digitorum longus muscle

Lysophosphatidic acid acyltransferase (LPAAT) δ/acylglycerophosphate acyltransferase 4 is a mitochondrial enzyme and one of five homologues that catalyze the acyl-CoA-dependent synthesis of phosphatidic acid (PA) from lysophosphatidic acid. We studied skeletal muscle LPAATδ and found highest levels in soleus, a red oxidative fibre-type that is rich in mitochondria, and lower levels in extensor digitorum longus (EDL) (white glycolytic) and gastrocnemius (mixed fibre-type). Using Lpaatδ-deficient mice, we found no change in soleus or EDL mass, or in treadmill time-to-exhaustion compared to wildtype littermates. There was, however, a significant reduction in the proportion of type I and type IIA fibres in EDL but, surprisingly, not soleus, where these fibre-types predominate. Also unexpectedly, there was no impairment in force generation by EDL, but a significant reduction by soleus. Oxidative phosphorylation and activity of complexes I, I?+?II, III, and IV in soleus mitochondria was unchanged and therefore could not explain this effect. However, pyruvate dehydrogenase activity was significantly reduced in Lpaatδ^?/? soleus and EDL. Analysis of cellular lipids indicated no difference in soleus triacylglycerol, but specific elevations in soleus PA and phosphatidylethanolamine levels, likely due to a compensatory upregulation of Lpaatβ and Lpaatε in Lpaatδ^?/? mice. An anabolic effect for PA as an activator of skeletal muscle mTOR has been reported, but we found no change in serine 2448 phosphorylation, indicating reduced soleus force generation is unlikely due to the loss of mTOR activation by a specific pool of LPAATδ-derived PA. Our results identify an important role for LPAATδ in soleus and EDL.