Perception of Kinematic Characteristics in the Motion of Lifted Weight

It has been widely shown that human observers are able to perceive lifted weight from the observation of a point-light display of the lifter's action. In the experiments reported here, the kinematic information used by observers to perceive a lifted weight was determined. In Experiment 1, observers (N = 30) were able to identify weights (5, 10, 15, 20, and 25 kg) successfully by observing only the lift phase of the action. Other procedures, such as walking while holding the weight and placing the weight on a table, did not result in significantly improved estimations. In Experiment 2, the kinematic patterns used by 4 lifters with weights varying from 5 to 25 kg were examined. Changes in weight lifted resulted in changes in lift velocity, hip angle, and dwell time. In Experiment 3, in which 15 observers participated, these 3 kinematic variables were experimentally manipulated. The results indicated that observation was most significantly influenced by variations in lift velocity. The results are discussed in relation to kinematic specification of dynamics and heuristic approaches.

A non-enzymatic p21 protein inhibitor of stress-activated protein kinases

The stress-activated protein kinases (SAPKs), which are identical to the c-Jun amino-terminal kinases (JNKs), are activated in response to a variety of cellular stresses, including DNA damage, heat shock or tumour-necrosis factor-alpha. SAPK, a subfamily of the mitogen-activated protein (MAP) kinases, is a major protein kinase that phosphorylates c-Jun and other transcription factors. SAPK phosphorylation of transcription factors is important in stress-activated signalling cascades. Here we report that the protein p21 WAF1/CIP1/Sd:1, a DNA-damage-inducible cell-cycle inhibitor, acts as an inhibitor of the SAPK group of mammalian MAP kinases. This highlights a new biochemical activity of p21, which may provide the first evidence for a non-enzymatic inhibitory protein for SAPK. We suggest that p21, by inhibiting SAPK, may participate in regulating signalling cascades that are activated by cellular stresses such as DNA damage.

Perinuclear anti-neutrophil cytoplasmic antibody and refractory pouchitis. A case-control study

Refractory pouchitis (RP) is a debilitating complication of ileal pouch reservoirs that affects approximately 2.5% of patients. Although the cause of RP is unknown, it is frequently hypothesized that it reflects underlying Crohn's disease. Since perinuclear anti-neutrophil cytoplasmic antibody (pANCA) is found in approximately 70% of ulcerative colitis patients but only rarely in Crohn's disease patients, it may help distinguish Crohn's disease from ulcerative colitis. Therefore, to test whether RP reflects "missed" Crohn's disease, we determined the ANCA status of 26 patients with RP. The pANCA was positive in 42% of cases [50% of Kock pouch cases and 33% of ileoanal pull-through (IAPT) cases] and 57% of matched control subjects without pouchitis (N = 42, P = NS). Moreover, 3/6 (50%) of IAPT RP subjects whose signs and symptoms most suggested Crohn's disease tested positive for pANCA. When compared to controls, IAPT cases exhibited significantly more preoperative extraintestinal manifestations (EIMs) of inflammatory bowel disease (P < 0.05). The presence of preoperative EIMs was 100% predictive of postoperative EIMs (P < 0.05). Review of pouch biopsies from cases of RP revealed no pathognomonic histologic features of Crohn's disease. These data confirm our previous suggestion that RP does not reflect underlying Crohn's disease but may be associated with the EIMs of inflammatory bowel disease.

The BOS1 gene encodes an essential 27-kD putative membrane protein that is required for vesicular transport from the ER to the Golgi complex in yeast

We recently described the identification of BOS1 (Newman, A., J. Shim, and S. Ferro-Novick. 1990. Mol. Cell. Biol. 10:3405-3414.). BOS1 is a gene that in multiple copy suppresses the growth and secretion defect of bet1 and sec22, two mutants that disrupt transport from the ER to the Golgi complex in yeast. The ability of BOS1 to specifically suppress mutants blocked at a particular stage of the secretory pathway suggested that this gene encodes a protein that functions in this process. The experiments presented in this study support this hypothesis. Specifically, the BOS1 gene was found to be essential for cellular growth. Furthermore, cells depleted of the Bos1 protein fail to transport pro-alpha-factor and carboxypeptidase Y (CPY) to the Golgi apparatus. This defect in export leads to the accumulation of an extensive network of ER and small vesicles. DNA sequence analysis predicts that Bos1 is a 27-kD protein containing a putative membrane-spanning domain. This prediction is supported by differential centrifugation experiments. Thus, Bos1 appears to be a membrane protein that functions in conjunction with Bet1 and Sec22 to facilitate the transport of proteins at a step subsequent to translocation into the ER but before entry into the Golgi apparatus.

BET1, BOS1, and SEC22 are members of a group of interacting yeast genes required for transport from the endoplasmic reticulum to the Golgi complex

A subset of the genes required for transport from the endoplasmic reticulum (ER) to the Golgi complex in Saccharomyces cerevisiae was found to interact genetically. While screening a yeast genomic library for genes complementing the ER-accumulating mutant bet1 (A. Newman and S. Ferro-Novick, J. Cell Biol. 105: 1587-1594, 1987), we isolated BET1 and BOS1 (bet one suppressor). BOS1 suppresses bet1-1 in a gene dosage-dependent manner, providing greater suppression when it is introduced on a multicopy vector than when one additional copy is present. The BET1 and BOS1 genes are not functionally equivalent; overproduction of BOS1 does not alleviate the lethality associated with disruption of BET1. We also identified a pattern of genetic interactions among these genes and another gene implicated in transport from the ER to the Golgi complex: SEC22. Overproduction of either BET1 or BOS1 suppresses the growth and secretory defects of the sec22-3 mutant over a wide range of temperatures. Further evidence for genetic interaction was provided by the finding that a bet1 sec22 double mutant is inviable. Another mutant which is blocked in transport from the ER to the Golgi complex, sec21-1, demonstrates a more limited ability to be suppressed by the BET1 gene. The interactions we observed are specific for genes required for transport from the ER to the Golgi complex. The products of the genes involved are likely to have a direct role in transport, as bet1-1 and sec22-3 begin to display their mutant phenotypes within 5 min of a shift to the restrictive temperature.