Characterization of spinach leaf α-l-arabinofuranosidases and β-galactosidases and their synergistic action on an endogenous arabinogalactan-protein

Two β-galaclosidases (β-Galase-I and -II, EC 3.2.1.23) and two α-l -arabinofuranosidases (α-l -Arafase-I and -II. EC 3.2.1.55). were purified from mesophyll tissues of spinach (Spinacia oleracea L.), using chromatography on DEAE-cellulose, lactose-conjugated Sepharose CL-4B, and Sephadex G-100, or on hydroxylapatite and Sephadex G-150. The apparent molecular mass (M_r) of β-Galase-I and -II, respectively, were estimated to be 38 000 and 58 000 on SDS-PAGE and 64 000 and 60 000 on gel-permeation chromatography, indicating that the former was a dimeric protein. The isoelectric points of β-Galase-I and -II were 6.9 and 5.2, respectively. Both enzymes hydrolyzed maximally p-nitrophenyl (PNP) β-galactoside at pH 4.3, and were activated about 2-fold in the presence of BSA (100 μg ml^?1). The activity of both enzymes was inhibited strongly by heavy metal ions and p-chloromercuriberszoate (p-CMB). d -Galactono-(1→4)-lactone and d -galactal served as potent competitive inhibitors for the enzymes. β-Galase-I and -II could be distinguished from each other in their relative rates and kinetic properties in the hydrolysis of aryl β-galactosides as well as of lactose and galacto-oligosaccharides. In particular. β-Galase-I exhibited a preferential exowise cleavage of β-1,6-galactotriose and β-1.3-galactan. α-l -Arafase-l (M_r 118000) and -II (M, 68 000) were optimally active on PNP α-l -arabinofuranoside at pH 4.8 and gave K_m values of 1.2 and 2.2 mM. respectively. l -Arabino-(1 → 4)-lactone. Ag⁺, and SDS acted as inhibitors for the isozymes. α-l Arafase-I was characterized by its activity to hydrolyze PNP β-d -xylopyranoside besides PNP α-l -arabinofuranoside. inhibition by d -xylose and d -glucono-(1 → 5)-lactone. and less sensitivity to Hg²⁺. Cu²⁺, and p-CMB. Sugar beet arabinan was hydrolyzed rapidly by α-l Arafase-II at one-half the rate for PNP α-l arabinofuranoside, while the polysaccharide was less susceptible to α-l Arafase-I. A spinach leaf arabinogalactan-protein was practically resistant to the action of β-Galases, but its susceptibility to the enzymes increased remarkably after prior hydrolysis with α-l Arafase-Il.     

A Serine Protease in Soybean Seeds That Acts Specifically on the Native {alpha} Subunit of {beta}-Conglycinin

A proteolytic activity directed against the     

Impalement of marine turtles (Reptitia,Chelonia: Cheloniidae and Dermochelyidae) by billfishes (Osteichthyes,Perciformes: Istiophoridae and Xiphiidae)

Synopsis Billfishes have long been known to impale a great variety of objects, but there are only two brief, obscure records of marine turtles being speared. Details are presented on these two, as well as on two other confirmed records; data from two additional unconfirmed records are also presented. In total, three species of marine turtles are known to have been impaled by three species of billfishes; a fourth species of fish and a fourth species turtle are listed in an unconfirmed case. Records come from the eastern and western Pacific as well as the eastern Atlantic. Of the four confirmed cases, the turtles survived in two, and apparently died as an effect of the spearing in the other two. In three confirmed cases only the impaled rostrum was encountered, and in one confirmed case the entire fish was found, with its rostrum piercing the turtle. There is no obvious advantage — or clear disadvantage — involved in impaling turtles. It is argued that these attacks are accidental, and the result of attempts made by the billfish to capture prey that are near the turtle. These spearings indicate that the chelonians serve as shelters for prey animals on the high seas, and thus, are further evidence of the pelagic existence of marine turtles. The impalings are evidence of a singular ecological role of the turtles — as live fish aggregation devices.     

Detection of Antibody-Coated Bacteria in Expectorated Sputum for Diagnosis of Lower Respiratory Infections

We evaluated antibody-coated bacteria (ACB) in expectorated sputum to discriminate contaminating or colonizing organisms from true pathogens. We examined 60 expectorated sputum samples from 51 patients with lower respiratory infections (chronic obstructive pulmonary disease 25, pneumonia 20, purulent tracheobronchitis 6). All samples were examined with quantitative culture and immunofluorescent demonstration of ACB. From the results of quantitative culture, we divided specimens into pathogen-isolated and pathogen-free samples. Among pathogen-isolated samples, in which we isolated accepted pathogenic organisms at ≥ 10⁷ colony-forming units per ml, 16 of 23 samples were ACB-positive (69.5%). In contrast, among pathogen-free samples, in which we isolated accepted pathogens at < 10⁷ colony forming units per ml or only upper respiratory flora, only 3 of 37 samples were ACB-positive (8.1%). The ACB-positive rate was significantly higher in pathogen-isolated than in pathogen-free samples (P < 0.001). Consequently, detecting ACB in expectorated sputum shows good potential as another criterion for distinguishing contaminating or colonizing organisms from true pathogens.     

Prevalence of Human Herpesvirus 6 Variants A and B in Patients with Chronic Fatigue Syndrome

Peripheral blood mononuclear cells collected from 13 patients with chronic fatigue syndrome and 13 healthy controls were analyzed for the presence of human herpesvirus 6 (HHV-6) DNA by variant-specific polymerase chain reaction and dot blot hybridization. HHV-6 DNA was detected in 7 of 13 (53%) patients, and of those 7 patients, 4 were positive for HHV-6 variant A DNA and 3 were for variant B. No HHV-6 DNA was detected in the controls. Serum antibody titers to the late antigen and antibody prevalence to the early antigen of HHV-6 were significantly higher in the patient group. These results suggest active replication of HHV-6 in patients with chronic fatigue syndrome.     

Human T Cell Leukemia Virus Type 1 (HTLV-1) Antibodies in Healthy Populations and Renal Transplanted Patients in the North-East of Brazil

The seroprevalence of human T cell leukemia virus type 1 (HTLV-1) infection was investigated in Brazilians (570): native inhabitants (298) and descendants from Japanese (272) living in Recife and its neighborhoods—North-east of Brazil. Furthermore, polytransfused renal transplanted patients (54) were also examined for the serological status to this virus. The seropositivity to HTLV-1, screened by enzyme-linked immunosorbent assay (ELISA), was low: 1.34% for the local population and 0.73% for the descendants from Japanese. However, the seropositivity for the renal transplanted patients was found to be 11.1%. This higher value suggests that this retrovirus infection seems to be of importance in this clinical condition.     

Molecular phylogeny in the Lardizabalaceae

Eleven species belonging to seven genera in the Lardizabalaceae were analyzed in terms of restriction fragment length polymorphism (RFLP) of chloroplast DNA and the sequence of the chloroplast gene,rbcL, of Lardizabalaceae and its related families. Phylogenetic trees inferred from parsimony, neighbor joining and maximum likelihood methods based on RFLP data showed that two South American genera,Boquila andLardizabala, and three East Asian genera,Akebia, Holboellia andStauntonia are closely related to each other, respectively. On the other hand, the parsimony, neighbor joining and maximum likelihood trees constructed using sequence data of therbcL gene showed thatAkebia, Stauntonia, Boquila andLardizabala clustered as(((Akebia, Stauntonia), Boquila), Lardizabala). This difference may be attributable to fewer informative sites inrbcL genes than in RFLP in this family.Decaisnea diverges at the very base of the Lardizabalaceae.     

Change in growth kinetics of hybridoma cells entrapped in collagen gel affected by alkaline supply

The growth yields for glucose and glutamine of murine hybridoma cells entrapped in collagen gel particles were examined during the growth phase. The immobilized hybridoma cells were cultivated in a fluidized bed fermenter where the medium was circulating to supply oxygen separately. Procedures to supply an alkaline solution for adjusting the pH level strongly affected the growth yields. A direct supply of the alkaline solution to the cultivation system reduced both the growth yields for glucose and glutamine, probably due to a local increase in pH level. On the other hand, when fresh medium in which the pH was adjusted to around 8.5 was added to the cultivation system, the growth yields were unchanged even at the same pH level as when direct alkaline supply was used. These results suggest that an indirect alkaline supply could be recommended to ajust the pH level when using medium-circulating-fermenters.     

Theoretical study of the electronic structure and conformation of polysilole and its derivatives

The electronic structures and conformations in the optimized geometries of polysilole and its derivatives are studied theoretically, using the one-dimensional tight-binding self-consistent field crystal orbital (SCF-CO) method. It has been found that the copolymer formed by alternating aromatic silole and quinoid thiophene has a relatively small bandgap value. We observe that polysilole may show an interesting thermochromic behavior, because the conformation of polysilole is considerably easier to change at lower temperature than that of polythiophene.     

Electronic structure of siloxene model compounds

The electronic structures of one-dimensional and two-dimensional siloxene (Si₆O₃H₆) model compounds have been examined theoretically, using the semiempirical tight-binding self-consistent field crystal orbital (SCF-CO) method. These compounds are formed by silicon-based chain and planar structures containing a regular array of oxygen atoms. Results show that the two-dimensional polysilane in which OH groups are substituted for H atoms possesses a relatively smaller direct gap than other siloxenes. It is assumed that the electronic structures of siloxenes are affected not only by the dimensionality of Si-Si -conjugational networks due to an array of oxygen atoms, but also by the diminishing of the electron population in the Si-Si bonding orbitals caused by oxygen atoms with large electronegativity.