Segmental flexibility and complement fixation of genetically engineered chimeric human, rabbit and mouse antibodies.

We generated a family of chimeric immunoglobulin G (IgG) molecules having identical antigen-combining sites for the dansyl (DNS) hapten, in conjunction with nine heavy chain constant (CH) regions. This family of antibody molecules allows comparison of CH dependent properties independent of possible variable region contributions to IgG function. The segmental flexibility and complement fixation activity were measured of six genetically engineered molecules (the four human IgG isotypes, mouse IgG3 and rabbit IgG) and the remaining three mouse IgG isotypes, (IgG1, IgG2a and IgG2b), isolated previously by somatic cell genetic techniques. These properties of antibody molecules each correlate with the length of the immunoglobulin hinge region which separate the first and second CH (CH1 and CH2) domains. These results attribute a structural basis for two critical properties of antibody molecules.     

Genetic characterization of mouse immunoglobulin allotypic determinants (allotopes) defined by monoclonal antibodies

We have generated a new series of monoclonal antibodies recognizing allotypic determinants on mouse IgG₁, IgG_2a, and IgG_2b. In this communication we describe their reactivities with immunoglobulins of the inbred mouse strains. Comparison with serology charts indicates that many of these monoclonal antibodies detect allotypic specificities previously defined by conventional antisera; others define previously undescribed specificities. Strain and isotype distribution allows us to assign five new allotypic specificities to Igh-1 and three new specificities to Igh-3. In addition, on the basis of reactivity with the monoclonal antibodies, we have defined a new Igh haplotype in SWR/J mice, Igh ^p.Abbreviations used in this paper Igh immunoglobulin heavy chain - SDS sodium dodecyl sulfate     

Are daughters more costly to produce for Japanese macaque mothers?: Sex of the offspring and subsequent interbirth intervals

Based on a sample of 237 live births recorded over a period of 30 years, a tendency for longer interbirth intervals following the birth of daughters than sons was recognized, in the provisioned Arashiyama troop of Japanese macaques. This may indicate that female infants were more costly to produce than male infants. This tendency seemed to be independent of a mother’s rank.     

Methane fermentation of xylan by mesophilic and thermophilic methane sludges

The degradation of xylan during methane fermentation proceeded as a first-order reaction. The rate constants were calculated to be 0.40–0.09 day^–1 at 37° C and 0.341 day^–1 at 55° C. From calculations based on the experimental data, K _A and C _A values in the expression of the velocity of xylose consumption changed as the fermentation progressed. In the mesophilic fermentation, the degradation of xylan slowed down after 2 days of incubation, but the rate of consumption of xylose increased between days 3 and 4 of incubation and slow again at the 5th day of incubation. In the thermophilic fermentation, the degradation of xylan proceeded at a constant rate and the rate of consumption of xylose increased slightly on the 3rd day of incubation. When the velocity of gas evolution was determined, the C _G value for acetate at 55° C was about 1.8 times larger than the value at 37° C.     

Optimization for xylanase and cellulase production from Aspergillus niger ATTC 6275 in palm oil mill wastes and its application

Optimization of enzyme production from Aspergillus niger ATCC 6275 under both submerged and solid-substrate cultivation was investigated. Results from submerged cultivation using palm oil mill effluent revealed that pretreatment of ground palm cake did not improve enzyme production. Addition of 0.60g NH4NO3/l generated maximum activity of xylanase and cellulase (CMCase). The optimum aeration rate was 1.2 v/v min. Under solid-substrate cultivation, the results indicated that heating and alkali treatment of the ground palm cake gave no further improvement in enzyme production. The optimal N-source was 2% urea. Optimal initial moisture contents for xylanase and CMCase activities were 60% and 50% respectively, with temperature optima of 30°C and 35°C, respectively. The optimal inoculum size was 1× 108 spores/g palm cake with an initial pH of 4.5–5.0. The maximum activities of xylanase (282.9U/g) and CMCase (23.8U/g) were obtained under the optimum conditions. Solid-substrate cultivation was a better method for the production of enzyme, particularly xylanase, from A. niger ATCC 6275. The application of these enzymes to decanter effluent showed the separation of oil and grease and suspended solids from the effluent. This is comparable to the result achieved from using the commercial xylase preparation Meicelase and superior to the effect of Sumyzyme.     

Further studies on aspartate aminotransferase of thermophilic methanogens by analysis of general properties, bound cofactors, and subunit structures.

Aspartate aminotransferase (AspAT) [EC 2.6.1.1] of thermophilic methanogen was further characterized with the enzyme from Methanobacterium thermoautotrophicum strain FTF-INRA as well as M. thermoformicicum strain SF-4. AspAT of strain FTF-INRA was similar in the amino donor specificity to the enzyme of M. thermoformicicum strain SF-4, in that it was active on L-cysteine and L-cysteine sulfinate in addition to L-glutamate and L-aspartate. The enzymes gave similar absorption spectra having maxima at around 326 and 415 nm with no pH-dependent shift but were found to contain 1 mol of tightly bound pyridoxal 5'-phosphate (PLP) per subunit. Reconstitution of each apoenzyme with added PLP resulted in partial recovery of the original enzymatic activity, suggesting a significant conformational change of the active site region upon removal of the cofactor. Polyacrylamide gel electrophoresis (PAGE) and gel filtration analyses revealed a tetrameric structure (180 kDa) of identical subunits with a molecular mass of 43 kDa for each of these enzymes. Electric current was found to affect the interaction or affinity of each subunit, promoting dissociation of the native enzyme into the monomeric form. Alkaline treatment was effective only for dissociation of the enzyme from strain SF-4. They were distinguishable by the more rapid reassociation of the monomer to the native aggregated form in the enzyme of strain FTF-INRA.     

Reproductive parameters of female Japanese macaques: Thirty years data from the arashiyama troops,Japan

Over a 30-year period from 1954 to 1983, 975 live births were recorded for Japanese macaque females at the Iwatayama Monkey Park, Arashiyama, Japan. Excluding unknown birth dates, primiparous mothers gave birth to 185 infants (182 cases with age of mother known) and multiparous mothers gave birth to 723 infants (603 cases with age of mother known). The peak month of birth was May with 52.3% of the total births occurring during the period. Multiparous females who had not given birth the previous year did so earlier than multiparous females who had given birth the previous year and also earlier than primiparous females. Among the females who had given birth the previous year, females whose infant had died gave birth earlier than females who had reared an infant the previous year. The offspring sex ratio (1:0.97) was not significantly different from 1:1, and revealed no consistent association with mother's age. Age-fecundity exhibited a humped curve. The annual birth rate was low at the age of 4 years but increased thereafter, ranging between 46.7% and 69.0%, at between 5 and 19 years of age, but again decreased for females between 20 and 25 years of age. Some old females displayed clear reproductive senescence. The infant mortality within the first year of age was quite low (10.3%) and the neonatal (less than 1 month old) mortality rate accounted for 49.0% of all infant deaths. There was no significant difference between the mortality rates of male and female infants. A female's rank-class had no apparent effect on the annual birth rate, infant mortality, and offspring sex ratio. These long-term data are compared with those from other primate populations.     

Generality of the action of various maturation-promoting factors

It has been known in amphibians and starfishes that a cytoplasmic factor called maturation-promoting factor (MPF), produced in maturing oocytes under the influence of the maturation-inducing hormones, can induce germinal vesicle breakdown (GVBD) and the subsequent process of meiotic maturation. The present study revealed that injection of cytoplasm of maturing starfish oocytes (starfish MPF) into immature sea cucumber oocytes brought about maturation of the recipients. Amphibian MPF obtained from mature oocytes of Xenopus laevis or Bufo bufo was found to induce maturation of starfish oocytes following injection. Cytoplasm taken from cleaving starfish blastomeres induced maturation when injected into immature starfish oocytes. The maturation-inducing activity of cytoplasm of starfish blastomeres changed along with the mitotic cell cycle during 1- to 4-cell stages so far tested and reached a peak just before cleaving. Furthermore, an extract of mammalian cultured cells, CHO or V-79, synchronized in M phase, induced GVBD in starfish oocytes following injection, whereas S phase extract had little activity. These facts suggest that MPF generally brings about nuclear membrane breakdown in both meiosis and mitosis, and that the nature of MPF is very similar among vertebrates and invertebrates.     

Rotational dynamics of monoclonal anti-dansyl immunoglobulins

The rotational motions of monoclonal mouse anti-dansyl immunoglobulins were studied by nanosecond fluorescence emission anisotropic spectroscopy using a mode-locked argon-ion laser as the pulsed excitation source. Three homogeneous antibodies of the immunoglobulin Gl (IgGl) subclass containing different V regions were prepared. The fluorescence emission maxima of these antibodies (designated as DNS1, DNS2 and DNS3) are at 515, 480 and 500 nm, respectively. Their mean rotational correlation times, 〈φ〉, are 84, 109 and 96 ns, respectively. The binding of protein A or a monoclonal anti-allotype antibody to the F_c unit of DNS1 increased 〈φ〉 to 142 and 150 ns, respectively, whereas reduction of the disulfide bond between the heavy chains decreased 〈φ〉 to 48 ns. These nanosecond measurements show that the rotational motion of the F_ab arms in mouse IgGl is restricted.