Isolation and Sequences of Peptic Peptides,and the Complete Sequence of Ile Chain of Ricin D

Sixteen peptic peptides, which contain arginine(s) or lysine, were isolated from cyanogen bromide fragments CB I and CB II of Ile-chain. Sequence determination has been performed on most of these peptides to provide overlaps for the tryptic peptides. Thus, complete amino acid sequence of Ile-chain consisting of 265 amino acid residues was determined. Some structural characteristics of the protein are also discussed.     

Urine 3-hydroxykynurenine is higher during the postovulatory phase than in the preovulatory phase indicating a higher vitamin B6 requirement

The relationship between l-tryptophan to nicotinamide metabolism and the menstrual cycle of Japanese women was investigated. Nine metabolism intermediates from urine samples collected during the preovulatory and postovulatory phases were measured. Only urine 3-hydroxykynurenine was higher in the postovulatory phase than in the preovulatory phase. This increase in 3-hydroxykynurenine suggests a decreased reaction of 3-hydroxykynurenine?→?3-hydroxyanthranilic acid catalyzed by kynureninase, a vitamin B₆ enzyme.     

Phase control of circadian activity in the antelope ground squirrel

Abstract

Wheel‐running activity of forty antelope ground squirrels, Ammospermophilus leucurus, was monitored for several months in both an outdoor cage and in the laboratory. The squirrels demonstrated a highly diurnal pattern which persisted in “constant conditions.” After removal from the field the initial free‐running period was close to 24 hrs, but typically lengthened in a nearly linear fashion at least for the first few months. There was no evidence of any difference in this trend for squirrels, in D/D, L/L 100 lx, 250 lx or 1200 lx. Eventually, about 90 percent of the squirrels had periods longer than 24 hrs.

The synchronizing capacity of the natural photoperiod was used to “catch the free‐running rhythm” and thereby demonstrate a response curve. Synchronization occurred by a shortening of the period when the time of sunrise was between 125° and 0° (subjective night) and by a lengthening of the period when the time of sunrise was between 0° and 125° (subjective day).

To more thoroughly examine the underlying mechanisms of phase control, phase‐response curves based on sixty one light‐pulse experiments were constructed. Comparisons of curves based on 6‐hr and 15‐min pulses, showed that the integral action of light is important (i.e., the entire pulse is involved in phase shifting). It was found that light pulses not only affected the phase of the rhythm but also the phase. Large phase shifts were usually associated with decreases in free‐running period. Several hypotheses on the controlling mechanisms were advanced.     

Not looking where you are leaping: a novel method of oriented travel in the caterpillar Calindoea trifascialis (Moore) (Lepidoptera: Thyrididae)

The prepupation caterpillar of the Southeast Asian moth Calindoea trifascialis constructs a leaf shelter that jumps across the ground using a jumping method novel among the insects. We found that movement path direction was correlated to the direction opposite to the most intense light. Correlated random walk (CRW) analyses found net squared displacements higher than predicted by a CRW, and fractal dimension analysis indicated straighter paths at large spatial scales. Rearing experiments showed high mortality from predation on the ground, but higher mortality resulted from sun exposure. We interpret jumping path orientation as an efficient search strategy to find shade in a variable landscape, given limited perception, in the presence of overheating and desiccation risks.     

An integrated practical implementation of continuous aqueous two‐phase systems for the recovery of human IgG: From the microdevice to a multistage bench‐scale mixer‐settler device

Aqueous two‐phase systems (ATPS) are a liquid‐liquid extraction technology with clear process benefits; however, its lack of industrial embracement is still a challenge to overcome. Antibodies are a potential product to be recovered by ATPS in a commercial context. The objective of this work is to present a more integral approach of the different isolated strategies that have arisen in order to enable a practical, generic implementation of ATPS, using human immunoglobulin G (IgG) as experimental model. A microfluidic device is used for ATPS parameters preselection for product recovery. ATPS were continuously operated in a mixer‐settler device in one stage, multistage and multistage with recirculation configuration. Single‐stage pure IgG extraction with a polyethylene glycol (PEG) 3350‐phophates ATPS within continuous operation allowed a 65% recovery. Further implementation of a multistage platform promoted a higher particle partitioning reaching a 90% recovery. The processing of IgG from a cell supernatant culture harvest in a multistage system with top phase recirculation resulted in 78% IgG recovery in bottom phase. This work conjugates three not widely spread methodologies for ATPS: microfluidics, continuous and multistage operation.     

MAD2γ, a novel MAD2 isoform,reduces mitotic arrest and is associated with resistance in testicular germ cell tumors

Background: Prolonged mitotic arrest in response to anti-cancer chemotherapeutics, such as DNA-damaging agents, induces apoptosis, mitotic catastrophe, and senescence. Disruptions in mitotic checkpoints contribute resistance to DNA-damaging agents in cancer. MAD2 has been associated with checkpoint failure and chemotherapy response. In this study, a novel splice variant of MAD2, designated MAD2γ, was identified, and its association with the DNA damage response was investigated.

Methods: Endogenous expression of MAD2γ and full-length MAD2 (MAD2α) was measured using RT-PCR in cancer cell lines, normal foreskin fibroblasts, and tumor samples collected from patients with testicular germ cell tumors (TGCTs). A plasmid expressing MAD2γ was transfected into HCT116 cells, and its intracellular localization and checkpoint function were evaluated according to immunofluorescence and mitotic index.

Results: MAD2γ was expressed in several cancer cell lines and non-cancerous fibroblasts. Ectopically expressed MAD2γ localized to the nucleus and reduced the mitotic index, suggesting checkpoint impairment. In patients with TGCTs, the overexpression of endogenous MAD2γ, but not MAD2α, was associated with resistance to cisplatin-based chemotherapy. Likewise, cisplatin induced the overexpression of endogenous MAD2γ, but not MAD2α, in HCT116 cells.

Conclusions: Overexpression of MAD2γ may play a role in checkpoint disruption and is associated with resistance to cisplatin-based chemotherapy in TGCTs.     

Effect of surface-screening parameter of the Yukawa potential model on vapour–liquid phase coexistence and critical-point properties of confined Yukawa fluid

We report the effect of surface-screening parameter of Yukawa potential model on vapour–liquid phase coexistence and critical-point properties of slit–pore-confined Yukawa fluid, using grand canonical transition-matrix Monte Carlo along with the histogram reweighting method. The effect of surface-screening parameter on the vapour–phase coexistence density is insignificant for the studied system. On the other hand, significant effect of surface-screening parameter is observed on liquid phase coexistence density. With increasing surface-screening parameter, liquid phase coexistence density decreases. Critical-point properties have shown monotonic decreasing trends with increase in surface-screening parameter. Moreover, the effect of change of surface-screening parameter is least on critical temperature changes as compared to critical density and critical pressure changes for the studied Yukawa system in this work.