Asparagine couples mitochondrial respiration to ATF4 activity and tumor growth

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Morphological changes in external and internal feeding structures during the transition phyllosoma-puerulus-juvenile in the Western Rock Lobster (Panulirus cygnus,Decapoda: Palinuridae)

External and internal feeding structures of the pelagic final phyllosoma, the transitional puerulus, and the benthic juvenile Western Rock Lobster, Panulirus cygnus, were studied by means of scanning electron microscopy. The study revealed that the external feeding structures of phyllosomata are well equipped for capture and mastication of food. The foregut, however, is not clearly divided into pyloric and cardiac regions and a gastric mill is absent, although a comb row and gland filter are present. Juveniles, on the other hand, have a well-developed gastric mill and gastric teeth, and a cardiopyloric valve separates the foregut into cardiac and pyloric regions. External mouthparts of juveniles are suitable for mastication of solid food particles and bear numerous setae. In contrast, external mouthparts of pueruli are largely non-setose. Furthermore, although the foregut is differentiated into pyloric and gastric regions and a gland filter and comb row are present, a functional gastric mill is absent during the puerulus stage. Absence of such structures indicates that the puerulus may be a non-feeding stage. It is postulated that absence of (or reduced) feeding may be a response to an increased risk of predation rather than a result of the considerable morphological changes taking place during the transition from a planktonic to a benthic lifestyle, as has been previously proposed. © 1994 Wiley-Liss, Inc.     

Control of asymmetric induction in the organometallic synthesis of 3-methyl-(E)-4-hexen-2-one

Bis(μ-methyl-1,3-dimethyl-η³-allylnickel) reacts in the presence of phosphorus(III) ligands (phosphines, phosphites) with CO to give 3-methyl-(E)-4-hexen-2-one. Systematic experiments were performed using chiral ligands containing menthyl or menthoxy groups and different achiral groups on the P atom to determine the influence of ligand structure and concentration on the direction and extent of chiral induction in this ketone synthesis. It could be shown that reversion of enantioselectivity can be obtained not only by the obvious method of reversing the absolute configuration of the ligand (“parity control”) but also by modifying the nonchiral substituents of the phosphorus ligand (“complementarity control”). The synthesis, physical, and spectroscopic properties of several new menthyl phosphines and phosphites are reported.     

Growth of axons through a lesion in the intact CNS of fetal rat maintained in long-term culture.

The ability of neurons in the central nervous system (CNS) to grow through a lesion and restore conduction has been analysed in developing spinal cord in vitro. The preparation consists of the entire CNS of embryonic rat, isolated and maintained in culture. Conduction of electrical activity and normal morphological appearance (light microscopical and electron microscopical) were maintained in the spinal cord of such preparations for up to 7 d in culture. A complete transverse crush of the spinal cord abolished all conduction for 2 d. After 3-5 d, clear recovery had occurred: electrical conduction across the crush was comparable with that in uninjured preparations. Furthermore, the spinal cord had largely regained its gross normal appearance at the crush site. Axons stained in vivo by carbocyanine dyes had, by 5 d, grown in profusion through the lesion and several millimetres beyond it. These experiments, like those made in neonatal opossum (Treherne et al. 1992) demonstrate that central neurons of immature mammals, unlike those in adults, can respond to injury by rapid and extensive outgrowth of nerve fibres in the absence of peripheral nerve bridges or antibodies that neutralize inhibitory factors. However, unlike the opossum, in which outgrowth occurred at 24 degrees C, although there was prolonged survival of rat spinal cords at this temperature, outgrowth of axons across the lesion required a temperature of 29 degrees C. With rapid and reliable regeneration in vitro it becomes practicable to assay the effects of molecules that promote or inhibit restoration of functional connections.     

Female-Female Competition in Bornean Orangutans

The mostly solitary ranging of orangutans and the large areas over which they traverse have hampered quantification of Bornean orangutan ranging patterns and feeding competition. Because of their semisolitary existence, female orangutans have few competitive interactions among themselves. However, contest and scramble types of competition occur, and researchers consider both to be important for the species. Using 9 yr of data and >22,300 h of observation of adult female orangutans in Gunung Palung National Park in Indonesian Borneo, we examined both forms of competition. Based on our analyses, we have 4 conclusions: 1) Adult female orangutans have highly overlapping home ranges, and thus there is potential for scramble competition to impose a cost. 2) Adult female orangutans actively avoid each other, suggesting that scramble competition indeed imposes a cost. 3) Adult females have distinct core areas that overlap to a lesser degree than home ranges do. 4) Analyses of contest competition reveal a slight spatial component to female competition for the first time. Preliminary evidence for core area defense and passive range exclusion may be among the mechanisms responsible for maintaining distinct adult female core areas.     

Rapid digestion of fish prey by the highly invasive ‘detritivore’Oreochromis mossambicus

Stomach residence time was tested over 24 h in three size classes of Oreochromis mossambicus using juvenile Lates calcarifer. In all 63 observations, the fish prey was digested within 24 h of consumption and most probably within 1 h, suggesting a need to re‐evaluate the trophic status and potential effects of this highly invasive species.