The hemolysin-like protein (HLP) Sll1951, characterized by the GGXGXDXUX nonapeptide motif implicated in Ca 2؉ binding, was purified from the glucose-tolerant strain (GT) of Synechocystis sp. strain PCC 6803. HLP was eluted at 560 kDa after gel filtration chromatography. Atomic absorption spectroscopy indicated that the protein bound calcium. The bound Ca 2؉ was not chelated with EGTA; however, it was released after being heated at 100°C for 1 min, and it rebound to the Ca 2؉ -depleted protein at room temperature. The apparent HLP molecular mass increased to 1,000 kDa and reverted to 560 kDa during the release and rebinding of Ca 2؉ , respectively. The monomers of the respective forms appeared at 90 and 200 kDa after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. HLP showed no apparent hemolytic activity against sheep erythrocytes; however, a slight hemolytic activity was detected during the conformational change caused by the rebinding of Ca 2؉ . Immunoelectron microscopy using polyclonal antibodies against the 200-kDa monomer revealed that HLP is located in the cell surface layer. The localization and Ca 2؉ -induced reversible conformational change suggest that HLP is a member of the repeat in toxin (RTX) protein family despite its latent and low toxicity. In some other cyanobacteria, RTX proteins are reported to be necessary for cell motility. However, the GT was immotile. Moreover, the motile wild-type strain did not express any HLP, suggesting that HLP is one of the factors involved in the elimination of motility in the GT. We concluded that the involvement of RTX protein in cyanobacterial cell motility is not a general feature.
This study was conducted to determine and compare the live traits, carcass yield and the physical, chemical, processing and sensory properties of meat from 20 Brahman grade cattle (crossbred cattle) and crossbred water buffalo (Philippine carabao × Murrah, Bulgarian or Indian) with an average age and weight of 29 months and 434 kg, respectively. The animals were fed a similar diet for 180 days before slaughter. A survey was performed to establish consumer meat preference between the two species. Live weights before slaughter of the two species were found to be different (P < 0.05) with the crossbred water buffalo showing higher bodyweight. However, the crossbred water buffalo had a lower (P < 0.05) dressing yield based on hot carcass weight and chilled carcass weight. The lower dressing yield of crossbred water buffalo can be attributed to its higher (P < 0.05) weights of edible and non‐edible slaughter by‐products. The chilled carcass yield of the forequarters and hindquarters from crossbred cattle and crossbred water buffalo were comparable when expressed as percent of live weight and chilled carcass weight. The estimated lean yield was higher in crossbred cattle than crossbred water buffalo. Crude protein, ash, fat, cholesterol, myofibrillar, sarcoplasmic and insoluble protein contents of the beef and carabao meat were all similar. Water holding capacity, pH, muscle fiber diameter, tenderness, firmness and marbling score in carabeef were all comparable to the beef. Redness was found to be higher (P < 0.05) in carabeef than the beef as measured with a color meter. The consumer meat preference survey showed that 55.9% selected the beef while 44.1% preferred carabeef. The color and amount of fat on the outside of the beef sample were primary in buyer selection.
Effects of a commercial probiotic, Bacillus cereus toyoi on abdominal fat accumulation in the Japanese quail fed either a commercial control diet (crude protein (CP), 23.5%; metabolizable energy (ME), 11.7MJ/kg) or a high-energy diet (CP, 23.0%; ME, 13.8MJ/kg) were investigated. Four-week-old male birds ( n = 108) were divided into four diet groups: control diet, control with probiotic, high-energy diet and high-energy diet with probiotic. At 8 weeks and 12 weeks of age (4 and 8 weeks of probiotic supplementation period, respectively), abdominal fat, muscles and the liver were weighed. The weight of total fat and protein in the muscles and liver were also determined. A rectal temperature was recorded weekly. Bodyweight and feed intake in both diets were not affected by probiotic supplementation. At 8 weeks of age, birds fed the control diet with probiotic had significantly less abdominal fat than those fed without the probiotic, and a similar tendency was seen for both diet groups at 12 weeks of age. The decrease in abdominal fat coincided with an increase in rectal temperature. These results suggest that greater metabolizable energy was consumed through elevation of heat production by supplementation of B. cereus toyoi , with hardly any energy stored as body fat. Probiotic supplementation appears to induce greater muscle weight, higher protein and lower lipid content in muscles by 8 weeks of age, and lower lipid content in muscles and greater liver weight by 12 weeks of age, in the Japanese quail.
Rumen bacteria of buffaloes and cattle, of which the former have been previously found to be consistently higher in concentration of bacteria than the latter, were separated from the solid (solid-associated bacteria; SAB) and the liquid (liquid-associatConcentration of bacteria and cellulase activity in each fraction in buffaloes were compared with those in cattle to clarify the effects of bacterial concentration on cellulose digestion in the rumen. Three pairs of each species were fed only with one of three roughages (in increasing order of quality; rice straw, timothy hay and alfalfa hay cubes) for 14 days. The same procedure was repeated exchanging the roughage for the other one being different in quality rotationally.Carboxymethyl cellulose was used as substrate for cellulase activity and 2, 6-diaminopimelic acid (DAP) as an indicator for bacterial matter.Concentration of DAP in SAB was higher in buffaloes than in cattle but cellulase activity was not significantly different between the species.Consequently, specific activity (cellulase activity/DAP) in SAB was significantly lower in buffaloes than in cattle. These results suggest that a higher bacterial concentration promotes attachment of bacteria to plant particles but the association of cellulolytic bacteria is not necessarily increased under this condition.Concentration of DAP, cellulase activity and specific activity in LAB in buffaloes remained high whichever roughage they were fed, whereas those in cattle in increased with quality of roughage.SAB in both species were lower in concentration of DAP but higher in cellulase activity and specific activity than LAB, indicating consistently higher celluloytic activity than LAB.Jpn. J. Zootech. Sci., 57 (4): 336-341, 1986 Key words: rumen bacteria, solid and liquid phases, cellulase activity, buffaloes and cattle Several experiments have shown that buffaloes utilize low quality feeds better than cattle1-3), presumably because buffaloes have more ruminal microbes. A higher concentration of microbes in the rumen may promote their association with plant particles, and this would be essential for degradation of structual polysaccarides such as cellulose. However, little is known about the activity of microbes associated with plant particles in the rumen, although considerable amounts of microorganisms adhere to plant materials 6,7). In the present paper, the concentration of bacteria and their cellulase activity in liquid and solid phases of the rumen digesta of buffaloes were compared with those of cattle to clarify the effects of microbial concentration on cellulose digestibility in the rumen. Cellulolytic activity of bacteria in the two phases was Jpn. J. Zootech. Sci., 57 (4): 336-341 336 1986
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