Fate of mimosine administered orally to sheep and its effectiveness as a defleecing agent.

Mimosine was administered orally to Merino sheep once daily for periods of 1-3 days, either as the isolated compound or in the foliage of Leucaena leucocephala. A single daily dose of mimosine of 450 or 600 mg/kg body weight was effective for defleecing sheep. A daily dose rate of 300 mg/kg was effective for defleecing sheep if given on two successive days. The effectiveness of a treatment for defleecing sheep was related to the concentration of mimosine in plasma following dosing; defleecing ensued when the concentration of mimosine in plasma was maintained above 0-1 mmol/l for at least 30 h. The main products excreted in urine were mimosine and 3,4-dihydroxypyridine (DHP); small amounts of mimosinamine were also excreted. During the first day following dosing, the major excretory product was mimosine; DHP was an important component during the second and third days. In the three days following the start of dosing, between 32 and 53% of the mimosine given was accounted for as mimosine in the urine. Following an intravenous infusion of mimosine, no DHP was detected in urine; most of the mimosine was excreted intact but a small amount (c. 9%) was excreted as mimosinamine.     

Effects of intravenous infusion of mimosine on wool growth of Merino sheep.

Merino sheep were given continuous intravenous infusions of L-mimosine for periods of 1 1/2, 2 or 21 days; efficacy as a defleecing procedure and effects on subsequent wool growth were measured. In addition, the amino acids tyrosine, phenylalanine and cystine were investigates as antagonists to the effects of mimosine. Infusions for 1 1/2 or 2 days at the daily rate of 80-120 mg/kg caused a cessation of wool growth by 1 1/2-2 days from the start of infusion, and all sheep were subsequently defleeced. It was estimated that, on average, fibre growth stopped for 10 1/2-13 days in four sheep after a 2-day infusion, and for 5 1/2 and 9 1/2 days in two sheep after an infusion for 1 1/2 days. There was considerable variation in the time taken for new fibres to recommence growth. During the period 3-5 weeks after infusion of mimosine, length growth rate was consistently greater than the pretreatment rate. Likewise, fibre diameter was greater in three out of the four sheep. As a result, the volume growth rate of fibres was greater post-treatment than it was pretreatment. Infusion for 3 weeks at the daily rate of 21-24 mg/kg did not stop wool growth. However, both length growth rate and fibre diameter were considerably depressed, and after 12 days' infusion, fibre diameter and volume growth rate were reduced to less than half the pretreatment values, and wool fibres were very weak. After the mimosine infusion stopped, fibre diameter increased to above pretreatment values and remained ther for the period of 2-3 weeks studied. The concurrent infusion of tyrosine, phenylalanine or cystine with mimosine failed to prevent any of the effects of mimosine on wool growth.     

Effects of intradermally injected and topically applied mouse epidermal growth factor on wool growth, skin and wool follicles of merino sheep

Twice daily intradermal (ID) injections of mouse epidermal growth factor (mEGF) in sterile saline for 1-4 days into delineated areas of skin of Merino sheep produced dose-dependent changes in wool follicles and fibres, ranging from slight reduction in follicle bulb size and transient disturbance of cuticle formation on some fibres to the induction of catagen of follicles and shedding of fibres with distorted, tapered ends. Regeneration of follicles commenced by day 7. By contrast, ID injections of saline did not affect follicle activity. The epidermis became thicker and more parakeratotic after multiple injections of mEGF than after injection of saline, but was almost normal again by day 14. Persistent small increases in sebaceous gland size, additional to those induced by ID injections of saline, and delayed small increases in sweat gland size also occurred after multiple injections of mEGF. Daily topical applications of mEGF in 50% (v/v) aqueous propylene glycol 5 days each week for 4 weeks did not affect wool growth or the follicles and other skin components. The only effect observed, due to application of the aqueous propylene glycol, was an increase in the number of layers of cornified cells in the stratum corneum of the epidermis, with the cells arranged in clearly discernible stacks. The effects produced by ID injections of mEGF indicate that mEGF acts directly on the pilosebaceous and epidermal components of skin.     

Effects of zinc deficiency on the wool growth, skin and wool follicles of pre-ruminant lambs

Two groups of 1-month-old pre-ruminant lambs of similar mean liveweights were fed identical liquid milk-replacer diets except that the zinc contents were either 5 micrograms (deficient diet) or 32 micrograms per gram of dry matter (control diet). These diets were fed for 4 weeks, after which all the lambs received the control diet for 2 weeks. In the lambs fed the deficient diet plasma zinc concentration decreased markedly during the first 2 weeks and skin lesions developed around their mouths. Autophagic vacuoles also developed in most follicle bulbs along with a variety of defects in the wool fibres and progressive inhibition of wool growth. Food intake and liveweight increase were not significantly depressed until the third and fourth weeks of feeding the deficient diet. During this period the wool was shed from the zinc-deficient lambs as a result of the fibres being degraded and distorted within thickened outer root sheaths in the distal (upper) parts of the follicles. In addition, the epidermis of the wool-bearing skin became slightly acanthotic and hyperkeratotic, although not parakeratotic. When the deficient lambs were fed the control diet for 2 weeks, their food intake, liveweight gain and plasma zinc concentration increased to almost those of the control lambs, but their rate of wool growth was still low and the epidermis had not returned to normal. Compared with previous studies the findings of this study suggest that pre-ruminant lambs may be more susceptible to the effects of zinc deficiency than ruminant lambs.     

Effects of growth hormone administration on wool growth in merino sheep

The effects of daily administration of 10 mg of highly purified ovine growth hormone (GH) for a period of 4 weeks on wool growth have been measured in 12 Merino ewes fed either a calculated maintenance energy intake or 1.6 times this amount (six on each ration). Concentrations of hormones, glucose, urea, alpha-amino N and amino acids in the blood were monitored and faeces and urine collected for measurement of nitrogen balance. Wool growth rate decreased by 20% during the 4 weeks of GH treatment in sheep fed the high energy diet, largely because of reduced wool fibre diameter. This was followed by restoration of normal growth and then an increase of up to 20% above control levels, a response which persisted for 12 weeks following cessation of GH administration, and which was due to increases in both fibre length and diameter. GH administration caused marked increases in plasma concentrations of GH, insulin and somatomedin C, glucose and free fatty acids, all of which returned to basal levels following cessation of GH administration. No consistent changes in plasma concentration of T3, T4, cortisol, prolactin or alpha amino N were detected. Plasma urea and methionine levels decreased during GH treatment and returned to, or were raised above, basal levels after the GH treatment period. GH injection also resulted in a net retention of N during treatment, followed by a transient period of net N loss. The GH-induced changes in wool growth may be caused by a change in the partitioning of amino acids between the muscle mass and the skin. No other contributing factor(s) were identified.     

Effects of abomasal supplements of methionine on the wool follicles and skin of wheat-fed sheep

In wheat-fed sheep, supplemented abomasally with 1.5-6.0 g methionine per day, poor formation and improper keratinization of the wool fibres were evident 4 days after the start of the methionine supplementation. This led to kinking of the fibres. Subsequently severe distortion of the fibres, accompanied by gross thickening of the outer root sheaths, occurred in the distal (upper) halves of most follicles. Within this thickened region partial degradation of the distorted fibres occurred before emergence from the skin surface, causing a marked reduction in the tensile strength of the wool. It is postulated that kinking of the fibres stimulated the accumulation of outer root sheath cells, which led to hyperactivity of the process that normally degrades the inner root sheath, so that the poorly keratinized fibres were also partly degraded. Thickening of the epidermis and cellular infiltration of the upper dermis sometimes occurred during the infusions of methionine, whereas there were negligible effects on the sebaceous and sweat glands. Disappearance of the excess accumulation of outer root sheath cells after cessation of the methionine supplementation occurred gradually following improvement in keratinization and elimination of kinking of the fibres.     

Morphological changes in the skin and wool fibres of Merino sheep infused with mouse epidermal growth factor

Intravenous infusion of 4.5-4.7 mg of mouse epidermal growth factor (mEGF) into nine castrated male Merino sheep for 26 h resulted in complete casting of the fleeces 6-8 days later. The morphological changes which occurred in the skin were studied in skin samples taken before infusion and at intervals between 1 h and 42 days after the infusion had begun. Wool fibres from the shed fleeces were examined with the scanning electron microscope. Increased cell proliferation occurred in the epidermis and sebaceous glands, whereas the wool follicles regressed. Transient dermal haemorrhages occurred during the first 3 h of infusion. The fibre and inner root sheath in the keratogenous zone of 30-40% of the follicles were partially disrupted within the first 6 h of mEGF infusion; catagen began in all follicle bulbs within 24 h. Fibre and inner root sheath production, although markedly reduced, continued in about 60% of follicles which had partially regressed, but production ceased in the remainder in which tapered ends formed on the fibres prior to shedding. Follicles began to regenerate asynchronously 4-8 days after the beginning of infusion and completed their development during the next 3 weeks. The follicle regression and fleece casting induced by mEGF infusion, and subsequent follicle regeneration were completed more rapidly than observed previously with other depilatory agents, and, except for prolonged epidermal thickening, there was no lasting cutaneous abnormality.     

Effects of SNP, ouabain, and amiloride on electrical potential profile of isolated sheep pleura.

The fluid and solute transport properties of pleural tissue were studied by using specimens of intact visceral and parietal pleura from adult sheep lungs. The samples were transferred to the laboratory in a Krebs-Ringer solution at 4 degrees C within 1 h from the death of the animal. The pleura was then mounted as a planar sheet in a Ussing-type chamber. The results that are presented in this study are the means of six different experiments. The spontaneous potential difference and the inhibitory effects of sodium nitroprusside (SNP), ouabain, and amiloride on transepithelial electrical resistance (R(TE)) were measured. The spontaneous potential difference across parietal pleura was 0.5 +/- 0.1 mV, whereas that across visceral pleura was 0.4 +/- 0.1 mV. R(TE) of both pleura was very low: 22.02 +/- 4.1 Omega. cm2 for visceral pleura and 22.02 +/- 3.5 Omega. cm2 for parietal pleura. There was an increase in the R(TE) when SNP was added to the serosal bathing solution of parietal pleura and to the serosal or mucosal bathing solution in visceral pleura. The same was observed when ouabain was added to the mucosal surface of visceral pleura and to either the mucosal or serosal surface of parietal pleura. Furthermore, there was an increase in R(TE) when amiloride was added to the serosal bathing solution of parietal pleura. Consequently, the sheep pleura appears to play a role in the fluid and solute transport between the pleural capillaries and the pleural space. There results suggest that there is a Na+ and K+ transport across both the visceral and parietal pleura.     

Investigations on the structural,vibrational, computational,and molecular docking studies on potential antidiabetic chemical agent Diosmetin

In the present study, the harmonic vibrational frequencies of Diosmetin(5, 7 dihydroxy‐2(3‐hydroxy‐4 methoxyphenyl) chromen‐4‐one) have been investigated by both experimental (FTIR and FT‐Raman) and theoretical (HF and DFT/B3LYP) method. The calculated harmonic vibrational frequencies were compared with experimental data. A detailed interpretation of the vibrational spectra of the compound has been made on the basis of the calculated potential energy distribution (PED). The ¹H, ¹³C NMR chemical shifts and TD‐DFT calculations of the molecule were calculated and compared with the available experimental observations. A study on the molecular electrostatic potential surface (MEP) of the compound was performed, and the electrophilic and nucleophilic reactive sites were identified. Furthermore, the inhibition effect of compound against aldose reductase enzyme has been analyzed by molecular docking method, and the results were compared with the standard drug. The docking study indicates that the investigated compound shows better inhibitory activity toward aldose reductase enzyme than the standard drug, and hence this study may be supportive in the field of drug discovery to design more potential antidiabetic agents.     

Long-term effects of short-term provision of protein-enriched diets on resistance to nematode infection, and live-weight gain and wool growth in sheep.

Weaner sheep that had been hand-fed on diets containing increasing concentrations of protein for a 9-week period (when uninfected, or infected with Haemonchus contortus) were studied during the next 69 weeks when put on to pasture as a single, unsupplemented flock. During the 9-week period, groups of 12 sheep (six infected, six uninfected) were offered one of five iso-energetic (9.0 MJ kg(-1)) diets containing 10, 13, 16, 19 or 22% crude protein. All sheep were treated with anthelmintic at the end of the 9 weeks and then put out to pasture for 69 weeks, where they were all subject to the same environmental variables including nematode larval challenge. During the grazing period, animals that had previously received the higher protein diets consistently had higher live-weight gain and wool production, higher antibody responses to both H. contortus and Trichostrongylus colubriformis antigenic challenge in vitro, and lower faecal nematode egg counts than did the lambs previously offered the lower protein diets. Faecal egg counts of the grazing sheep that had been artificially infected with H. contortus while being hand-fed were similar to those of the uninfected sheep and there was no interaction between previous infection and dietary protein concentration. We conclude that short periods of enhanced post-weaning nutrition can have long-term and perhaps life-long effects on production.     

Studies on the in vitro metabolism of [3H]cortisol and [3H]oestradiol by sheep skin and wool roots.

The in vitro metabolism of [3H]cortisol, [3H]cortisone and [3H]estradiol-17 beta by adult sheep skin and wool follicle tissue (wool roots) was examined. The main metabolic product of the incubation of [3H]cortisol with sheep skin was [3H]cortisone, and the conversion was reversible. Wool roots were unable to carry out detectable interconversion, nor did this tissue give rise to other significant metabolites. Sheep skin and wool roots both rapidly converted [3H]oestradiol-17 beta to [3H]oestrone and the conversion could be carried out by follicle and non-follicle skin structures. It is suggested that sheep skin contains both 11 beta- and 17 beta-hydroxysteroid dehydrogenases, but that wool follicles contain only the latter enzyme.     

Effects of exogenous ATP on short-circuit current and potential difference of the isolated frog skin.

The addition of ATP (10(-3) M = final concentration) to the bathing medium of either side of the isolated frog skin resulted in parallel increases in potential difference and short-circuit current. Reductions in these electrical parameters induced by anaerobic conditions and sodium azide could be partially reversed by exogenous ATP. The response is apparently not mediated by cyclic adenylic acid, as it was not enhanced by theophylline. Ouabain failed to reduce rates of phosphate liberation induced by ATP, although potential difference and short-circuit current were reduced.     

Detection of a 65 kDaras binding protein in rat and sheep brain cytosol using a chemical cross linking agent

The ability of aras protein to associate with proteins present in rat brain cytosolin vitro was investigated using chemical cross-linking agents and the¹²⁵I-labelled v-H-ras protein. Two iodinated protein complexes with apparent molecular weights of 40 and 85 kDa were observed when a mixture of rat brain cytosol and [¹²⁵I]ras was treated with the cross-linking agent disuccinimidyl suberate and subjected to SDS-PAGE. Formation of the [¹²⁵I] 85 kDa complex was enhanced by a high concentration of EDTA while generation of the 40 kDa species was abolished by this treatment. Formation of the [¹²⁵I] 85 kDa complex was inhibited by unlabelledras protein, GTP, GTPS, and GDP but not by ATPS and GMP.Chromatography of the cross-linked brain cytosol-[¹²⁵I]ras mixture on DEAE cellulose partially resolved the [¹²⁵I] 85 kDa complex from the [¹²⁵I]ras protein. The [¹²⁵I] 85 kDa complex (formed using ethyleneglycolbis (succinimidylsuccinate) as the cross-linking agent) could be immunoprecipitated using a rabbit anti-ras polyclonal antibody. Treatment of the immunoprecipitate with hydroxylamine to cleave the cross-link yielded [¹²⁵I]-labelledras. A substantial enrichment of the proportion of the [¹²⁵I] 85 kDa complex in the cross-linked extract was achieved by preparative SDS-PAGE. It is concluded that thein vitro chemical cross-linking approach employed here has detected tworas binding proteins in rat brain cytosol: a 65 kDa heat-sensitive and a 20 kDa heat-stable protein. The possibility that the 65 kDaras binding protein is aras regulatory orras effector protein which has not so far been characterised is briefly discussed.Abbreviations DSS disuccinimidyl suberate - EGS ethyleneglycolbis (succinimidylsuccinate) - GTPS guanosine 5-[-thio] triphosphate - ATPS adenosine 5-[-thio] triphosphate     

xP2, a new member of the P-domain peptide family of potential growth factors, is synthesized in Xenopus laevis skin.

Similarly to epidermal growth factor (EGF) and EGF-like repeats, the "P-domain" represents a cysteine-rich module that has been detected in the past in a variety of polypeptides, as well as in high molecular weight proteins. Here, a precursor for a secretory polypeptide (xP2) is characterized that consists of two P-domains. xP2 has been discovered in Xenopus laevis with the help of the polymerase chain reaction. In contrast to all other P-domain peptides, it is synthesized in the skin but not in the stomach or the pancreas. By this and other criteria, it cannot be considered simply as the X. laevis homologue of recently described P-domain peptides, viz. the spasmolytic polypeptides (PSP/hSP/mSP). Furthermore, a polyclonal antiserum was generated against the deduced C-terminal end of xP2. Due to its immunoreactivity with granular glands, as well as with the epidermis, the possibility of a growth factor activity for xP2 in the germinal layer is discussed.     

Evaluation of cetyltrimethylammonium bromide as a potential short-term preservative agent for stripped goat skin

The aim of the present study was to evaluate cetyltrimethylammonium bromide (CTAB) as a short-term preservative agent for stripped goat skin, as an alternative to common salt (sodium chloride), the presently used preservative in the leather industry. Bacteria were isolated from the stripped goat skin at various time intervals and 16S rDNA sequencing results showed the presence of both Gram positive and Gram negative bacteria in stripped goat skin. All the bacterial isolates were inhibited by CTAB with MICs of 0.5–24.5 mg l⁻¹. Application of CTAB against microbial consortium on stripped goat skin showed that skin sample kept in 5% CTAB solution for 10 min did not contain any bacterial growth even after 12 days storage at room temperature. Scanning electron microscopy analysis and physical testing of skin preserved using CTAB did not reveal any bacterial attack on fiber structure of skin. This study shows that CTAB can be applied as a viable alternative to NaCl which generates a huge amount of pollution there by reducing pollution from leather processing.