Isolation of dihydroxylupene and dihydroxylupane from the bark of Lawsonia inermis

Two pentacyclic triterpenes isolated from the bark of henna were identified as 3β, 30-dihydroxylup- 20(29)-ene (hennadiol), and (20S)-3β, 30-dihydroxylupane. The assignment of the C-20 configuration in the latter compound was supported by the analysis of Eu(fod)₃-induced ¹H NMR chemical shifts in the two C-20 epimers synthesized from lupeol.     

Effect of cell immobilization and organic solvents on sulfoxidation and steroid hydroxylation byMortierella isabellina

Summary The effects of calcium alginate bead immobilization and the presence of organic solvents on two bioconversion reactions carried out byMortierella isabellina ATCC 42613 have been investigated. These reactions, the 14-hydroxylation of progesterone and the sulfoxidation of thioanisole, both proceed in high yield using resting-cell bioconversions, but are not carried out by alginate bead preparations in the absence of an organic co-solvent, the best results being obtained with 5 or 10% aqueous methanol. The stereoselectivity of sulfoxidation, of thioanisole was found to be dependent upon the nature and concentration of organic co-solvent.     

Analysis of the Structure of Surgical Activity for a Suturing and Knot-Tying Task

Background

Surgical tasks are performed in a sequence of steps, and technical skill evaluation includes assessing task flow efficiency. Our objective was to describe differences in task flow for expert and novice surgeons for a basic surgical task.

Methods

We used a hierarchical semantic vocabulary to decompose and annotate maneuvers and gestures for 135 instances of a surgeon’s knot performed by 18 surgeons. We compared counts of maneuvers and gestures, and analyzed task flow by skill level.

Results

Experts used fewer gestures to perform the task (26.29; 95% CI = 25.21 to 27.38 for experts vs. 31.30; 95% CI = 29.05 to 33.55 for novices) and made fewer errors in gestures than novices (1.00; 95% CI = 0.61 to 1.39 vs. 2.84; 95% CI = 2.3 to 3.37). Transitions among maneuvers, and among gestures within each maneuver for expert trials were more predictable than novice trials.

Conclusions

Activity segments and state flow transitions within a basic surgical task differ by surgical skill level, and can be used to provide targeted feedback to surgical trainees.     

Higher environmental temperature-induced change in synaptosomal acetylcholinesterase activity of brain regions

Expcsure of adult male albino rats to higher environmental temperature (HET) at 35° for 2–12 hr or at 45° for 1–2 hr increases hypothalamic synaptosomal acetylcholinesterase (AChE) activity. Synaptosomal AChE activity in cerebral cortex of rats exposed to 35° for 12 hr and in cerebral cortex and pons-medulla of rats exposed to 45° for 1–2 hr are also activated. AChE activity of synaptosomes prepared from normal rat brain regions incubated in-vitro at 39° or 41° for 0.5 hr increases significantly in cerebral cortex and hypothalamus. The activation of AChE in ponsmedulla is also observed when this brain region is incubated at 41° for 0.5 hr. Increase of (a) the duration of incubation at 41° and (b) the incubation temperature to 43° under in-vitro condition decreases the synaptosomal AChE activity. Lioneweaver-Burk plots indicate that (a) in-vivo and invitro HET-induced increases of brain regional synaptosomal AChE activity are coupled with an increase ofV _max without any change inK _m (b) very high temperature (43° under in-vitro condition) causes a decrease inV _max with an increase inK _m of AChE activity irrespective of brain regions. Arrhenius plots show that there is a decrease in transition temperature in hypothalamus of rats exposed to either 35° or 45°; whereas such a decrease in transition temperature of the pons-medulla and cerebral cortex regions are observed only after exposure to 45°. These results suggests that heat exposure increases the lipid fluidity of synaptosomal membrane depending on the brain region which may expose the catalytic site of the enzyme (AChE) and hence activate the synaptosomal membrane bound AChE activity in brain regions. Further the in-vitro higher temperature (43°C)-induced inhibition of synaptosomal AChE activity irrespective of brain regions may be the cause iof partial proteolysis/disaggregation of AChE oligomers and/or solubilization of this membrane-bound enzyme.To whom to address reprint requests:     

Greater Vulnerability of the Infecting Viral Strand of Replicative-Form Deoxyribonucleic Acid of Bacteriophage φX174

Four types of phiX-infected cells of Escherichia coli CR, a thymine-requiring strain of E. coli C, were prepared in which the parental replicative-form deoxyribonucleic acid (RF DNA) was labeled with same specific amounts of bromouracil in (i) both strands, (ii) only the infecting viral strand, (iii) only the complementary strand, and (iv) neither strand. The sensitivity of each type of infected cell toward irradiation by ultraviolet light, visible light, and X rays was measured. The results indicate that a certain amount of radiation damage in the infecting viral strand of the parental RF was more inhibitory to the production of progeny phage than when the damage was in the complementary strand. Similar conclusions were also drawn from "suicide" experiments of the phage-infected complexes containing (32)P of the same specific activity on either strand of the parental RF DNA. The results suggest that the beta decay occurring in the infecting viral strand was more effective in inactivating the plaque-forming ability of the complex.     

Effects of intravasal nylon thread on the spermatozoa & reproductive organs in rats.

An investigation was undertaken in rats to study the effects of intr avasal thread (IVT) on the spermatozoa in the vas deferens and reproduct ive organs at various intervals after IVT insertion. The quantity of sperm was slightly reduced and motility was greatly reduced in the distal portion of the vas. The percentage of head and tail separation of sperm in the distal vas decreased with time. The quantity of sperm always remained the same in the cauda epididymis although the percentage of motile sperm decreased at 1 and 6 months, but not at 9 months, after IVT insertion. Following IVT insertion there was insignificant change in the weight of the testis, epididymis, ventral prostate, and seminal vesicles and alkaline phosphatase activity in the ventral prostate. Although cause and significance of these findings are unclear, the sialic level in the epididymis was significantly reduced in all groups bearing IVT. The presence of IVT apparently causes a change to occur in the epididymis, but it is unknown whether this affects sperm maturation.     

Ultraviolet reactivation of the single stranded DNA phage phiX 174.

Summary When UV-irradiated X174 was grown in pre-irradiated host cells of various strains, ultraviolet reactivation (UVR) was observed only in recombination proficient strains such as E. coli C (uvrA ⁺ recA ⁺) and HF4704 (uvrA ^- recA ⁺), but not in the recombination deficient strain HF4712 (uvrA ⁺ recA ^-). By increasing the multiplicity of infection, no rise in the amount of such reactivation was observed. From the study of the neutral and alkaline sucrose gradient sedimentation patterns of DNA samples extracted from unirradiated cells infected with unirradiated phage, it appears that after the conversion of the viral single stranded (SS) DNA to the double stranded form (DS), nicks or scissions were produced on it within all three strains, which were ultimately sealed up in the recA ⁺ but persisted within the recA ^- host cells. When UV-irradiated phage infected unirradiated host cells, such nicking of the DS DNA appeared to be much more extensive in uvrA ⁺ recA ⁺, but slightly reduced in uvrA ⁺ recA ^- and severely suppressed in uvrA ^- recA ⁺ strains. When the host cells were also UV-irradiated, the conversion of the infecting viral SS DNA to DS DNA as well as its subsequent nicking were reduced in all the three strains to a much greater extent. Although nicking of the DS DNA molecule is an essential step even in the normal intracellular replication of X DNA, the production and the sealing up of such nicks appear not to have any positive correlation with UVR of these phages. A drastic reduction in nicking due te pre-irradiation of the host cells might, however, mean slowing down of the replication of the damaged parental RF molecules which would facilitate their repair perhaps through recombination with the homologous parts of the host genome.     

Mapping of mycoplasma virus DNA replication origins and termini.

A pulse-labeling protocol has been used to study DNA replication and map replication origins and termini in mycoplasma viruses L2 and L2ins1. The L2 genome is circular, double-stranded DNA of 11.63 kilobase pairs (kb), and the 14.89-kb L2ins1 genome is L2 DNA containing a 3.26-kb insertion. The data show that DNA replication is bidirectional from two origins in L2 and three origins in L2ins1. The extra origin in L2ins1 arises from the fact that one of the L2 origins is in one of the sequences that have been shown to be duplicated and transposed in the generation of L2ins1 from L2.     

Nonspecific primer and PCR generated hybridization probes for physical ordering large restriction fragments in complex genome of S. aureus.

Pulsed field gel electrophoresis (PFGE) allows separation of large restriction fragments from bacterial genome. Restriction fragments obtained by digestion of Staphylococcus aureus DNA with rare cutting enzymes (Sma I, and Csp I) were separated by PFGE. To arrange the physical order of the fragments generated by digestion with one enzyme, probes were prepared by nonspecific priming and polymerase chain reaction (PCR), using individual fragments of the other enzymatic digest as a template. Probes were then used for Southern hybridization to the PFGE separated fragment distribution of the two infrequent cleaving enzymes (Sma I and Csp I). Using probes generated from four Sma I fragments and five Csp I fragments as individual templates, a partial physical order of Csp I fragments of the genome of S. aureus ISP8 has been determined in relation to a previously published Sma I map of S. aureus genome.     

Restriction fragment fingerprint and genome sizes of Staphylococcus species using pulsed-field gel electrophoresis and infrequent cleaving enzymes.

Large restriction fragments of genomic DNA from Staphylococcus species were separated by pulsed-field gel electrophoresis (PFGE). Five different strains of S. aureus (ISP8, SAU3A, PS96, ATCC 6538, ATCC 15564) and three representative strains of S. haemolyticus SM102, S. warneri MCS4, S. cohnii LK478 from human hosts, and one strain of S. aureus (ATCC 8432) from an avian host were used in this study. Since Staphylococcus is A + T rich (approximately 67%), restriction fragments were obtained by digesting chromosomal DNA with endonucleases that recognize GC-rich sequences. Five enzymes Csp I, Sma I, Ecl XI, Ksp I, or Sac II were used for generation of few (7 to 16) distinctly separated fragments, with average sizes in the range of 200-300 kb. The size distribution of restriction fragments for each enzyme for each strain produced a strain-identifying fingerprint, and the genome size of each strain was determined from such restriction fragments separated by PFGE.