Chest-wall reconstruction by contralateral latissimus dorsi musculocutaneous flap

Reconstruction of chest wall and axilla are performed in 11 patients using a contralateral latissimus dorsi musculocutaneous flap. The entire lattisimus dorsi muscle, including the fascial portion, safely carried an island of skin from the area of the lumbodorsal fascia to the contralateral axilla. The flap was transposed to the defect through a tunnel between the pectoralis major and minor muscles. Most patients who needed reconstruction of the chest wall and axilla had compromised ipsilateral vasculature that prohibited its use in a pedicled flap but had an intact contralateral chest wall, axilla, and thoracodorsal vessels. Therefore, this procedure was performed easily in comparison with a free flap or pedicled omental flap. This is a new, valuable application for the versatile latissimus dorsi musculocutaneous flap.     

Mutagenic properties of 2-amino-N6-hydroxyadenine in Salmonella and in Chinese hamster lung cells in culture

The mutagenicity of the base analogue, 2-amino-N6-hydroxyadenine (AHA), was tested in Salmonella typhimurium TA100 and TA98 and in Chinese hamster lung (CHL) cells. AHA showed very potent mutagenicity in TA100 without S9 mix, inducing 25,000 revertants/micrograms. The mutagenicity increased about 2-fold upon addition of S9 mix containing 10 microliters S9. AHA was found to be one of the strongest mutagens for TA100. Addition of S9 mix containing 100 microliters S9 induced no significant increase of revertants with AHA at amounts up to 50 ng per plate. AHA was also mutagenic for the frameshift mutant, TA98, without S9 mix, the mutagenicity for TA98 being about 1/1000 of that for TA100. When the mutagenicity of AHA was tested in CHL cells, with diphtheria toxin resistance (DTr) as a selective marker in the absence of S9 mix with a 3-h treatment of cells, DTr mutants increased dose-dependently at concentrations of 2.5-15 micrograms/ml. When cells were incubated with AHA for 24 h, a 200-fold increase in the number of DTr mutants was observed; the mutagenicity was 500-fold higher than that of ethyl methanesulfonate. This marked increase of mutagenicity by prolonged incubation may indicate that AHA induces mutations mainly after incorporation into DNA. The addition of a small amount of S9 increased the mutagenicity obtained with a 3-h treatment 2-fold, but a larger amount of S9 decreased the mutagenicity as was found with S. typhimurium TA100.     

The parasitoidOoencyrtus nezarae (Hymenoptera: Encyrtidae) prefers hosts parasitized by conspecifics over unparasitized hosts

Summary Two laboratory experiments were conducted to examine the ovipositional preferences of the egg parasitoidOoencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) for parasitized and unparasitizedMegacopta punctatissimum Montandon (Hemiptera: Plataspidae). Females that had never oviposited or that had not oviposite for 3 days preferred recently parasitized hosts more than unparasitized hosts. The preference for recently parasitized hosts appeared to be mediated by the punctures in already parasitized hosts made by the ovipositor of the first female. Survival of the parasitoid progeny was lower in recently parasitized hosts than in unparasitized hosts. However, handling time of parasitized hosts was extremely short relative to that of unparasitized hosts, because the superparasitizing female could use the punctures made by the previous females. It is concluded that the females preferred the parasitized hosts over unparasitized hosts because the benefit of saving time and energy for drilling was more than the cost of progeny survival.     

Effect of Supra-High Irradiation on the Photosynthetic System of the Cyanophyte Synechocystis PCC 6714

Stability of thylakoid components under supra-high irradiancewas studied with the cyanophyte Synechocystis PCC 6714. Theactivity of overall photosynthesis was quickly inactivated (T_1/2=20min) under supra-high irradiance (300 W m^–2, white light).In parallel with the inactivation of photosynthesis, QA in PSII was also inactivated. Both inactivations were acceleratedby chloramphenicol (CAP) addition. The reactivation of PS IIrequired weak irradiation and was suppressed by CAP. However,PS I measured as P700 was very stable. The level of PS I measuredas P700 was not significantly reduced by the irradiation for12 h even in the presence of CAP while the level of Cyt b₅₅₉,component of PS II, was decreased markedly. The function ofPS I before and after supra-high irradiation with CAP was examinedby comparing sizes of P700 oxidation induced by a short flash,by a continuous light, and by determination of O₂-and ferredoxin-reduction.No difference was observed in PS I actions before and afterthe irradiation treatment. These results indicate that the PSI complex is very tolerant of supra-high irradiation. However,the cells grown under supra-high irradiance contained much fewerPS I and PS II complexes than Cyt b₆–f complexes. Theformer levels were reduced to a half to one fourth of thosebefore growth while the level of Cyt b₆–f complex wasnot reduced so much. A possible mechanism for changes in thylakoidcomposition under supra-high irradiation was discussed. (Received February 16, 1991; Accepted June 12, 1991)     

Lid margin reconstruction with an orbicularis oculi musculocutaneous advancement flap and a conchal cartilage graft

A simple method to reconstruct the midlateral lid margin defect is described using an orbicularis oculi musculocutaneous advancement flap and a free conchal cartilage graft. This method is easy to perform not only in the lower eyelid, but also in the upper one, provides a natural gray line and a stable lid margin without postoperative eversion, and substitutes for the Leone and van Gemert procedure.     

Defining the sequence recognized with BmFTZ-F1, a sequence specific DNA binding factor in the silkworm, Bombyx mori, as revealed by direct sequencing of bound oligonucleotides and gel mobility shift competition analysis.

BmFTZ-F1 is a Bombyx mori homologue of FTZ-F1, a positive regulator of the fushi tarazu gene of Drosophila melanogaster. In order to determine the sequence recognized with this factor, we made three sets of oligonucleotide mixture which contain 4 possible nucleotides at different positions within the previously proposed 12-bp binding consensus sequence. Oligonucleotides which bound to purified BmFTZ-F1 were separated by a gel mobility shift procedure and a binding sequence was determined by direct sequencing through Maxam-Gilbert method. By this analysis, 7 positions showed clear sequence preference and 5 positions showed weak or no sequence preference. The importance of each nucleotide at each position was confirmed by a gel mobility shift competition analysis and results were presented as a quantitative difference in the binding affinity. From these analyses, we conclude that the best binding sequence of BmFTZ-F1 is 5'-PyCAAGGPyCPu-3'. This method may be useful for the determination of a binding sequence of other sequence specific DNA binding factor.     

Mutual interactions between optic lobe circadian pacemakers in the cricket Gryllus bimaculatus

The coupling mechanism between the bilaterally paired optic lobe circadian pacemakers in the cricket Gryllus bimaculatus was investigated by recording locomotor activity, under constant light or constant red light, after the optic nerve was unilaterally severed.

Analyses of intramolecular disulfide bonds in proteins by polyacrylamide gel electrophoresis following two-step alkylation

A method that makes use of polyacrylamide gel electrophoresis was developed for the analysis of intramolecular disulfide bonds in proteins. Proteins with different numbers of cleaved disulfide bonds are alkylated with iodoacetic acid or iodoacetamide as the first step. The disulfide bonds remaining were reduced by excess dithiothreitol, and the newly generated free sulfhydryl groups were alkylated with the reagent not yet used (iodoacetamide, iodoacetic acid, or vinyl-pyridine) as the second step. This treatment made it possible for lysozyme (Mr, 14,000; 4 disulfides), the N-terminal half-molecule of conalbumin (Mr, 36,000; 6 disulfides), the C-terminal half-molecule of conalbumin (Mr, 40,000; 9 disulfides), and whole conalbumin (Mr, 78,000; 15 disulfides) to be separated by acid-urea polyacrylamide gel electrophoresis into distinct bands depending on the number of disulfide bonds cleaved. The method allowed us to determine the total number of disulfide bonds in native proteins and to assess the cleaved levels of disulfide bonds in partially reduced proteins. Two-step alkylation used in combination with radioautography was especially useful for the analysis of disulfide bonds in proteins synthesized in complex biological systems.