Purification of chicken testicular müllerian inhibiting substance by ion exchange and high-performance liquid chromatography

A highly purified protein molecule was obtained from the secretory proteins of 8-week-old chicken testes using ion-exchange column chromatographic procedures, including DEAE Bio-Gel A, CM Bio-Gel A, wheat germ lectin columns, and high-performance liquid chromatographic (hplc) separation techniques. This protein molecule has a molecular weight of 74,000 Da (74K protein). The isolated 74K protein induces regression of chicken Müllerian ducts grown in vitro. The 74K protein does not cause regression of cultured embryonic intestine or Wolffian duct. When the total testicular secretory proteins are resolved in a two-dimensional gel electrophoresis, approximately 120 polypeptides are obtained. The purified 74K protein has a pI of 6.1. Analysis of amino acid composition indicates that the 74K protein is relatively acidic in nature with a ratio of acidic to basic amino acids of 1.93.

Climbing fiber afferent modulation during a visually guided, multi-joint arm movement in the monkey

During a visually guided, multi-joint voluntary arm movement Purkinje cell simple and complex spike activity was recorded from the ipsilateral hemisphere and intermediate zone of the cerebellum in the rhesus monkey. The task consisted of moving a manipulandum over a horizontal video screen. Manipulandum (hand position) was represented by a cursor on the screen, the animal required to place the manipulandum within displayed start and target boxes. Purkinje cell complex spike discharge was examined using two paradigms. In the first the animal moved the manipulandum from a start box to a target box. In the second the animal was required to modify an ongoing movement and place the cursor within a repositioned target box. A majority of the cells (44/74) exhibited a statistically significant increase in the probability of complex spike discharge at various times during the movement. The increase was observed when the movement trajectory was redirected (36/44) and/or during the initial portion of the movement (27/44). These results suggest the climbing fiber afferent system is routinely involved in the execution of multi-joint movements especially when the movement is redirected. Possibilities include that climbing fiber afferent input is required when the motor state changes and/or during errors in motor performance.

Climbing fiber afferent modulation during treadmill locomotion in the cat

The relationship of the climbing fiber afferent discharge to the unperturbed and perturbed step cycle was evaluated in the cat. Following a precollicular-premamillary decerebration, cats walked spontaneously on a motorized treadmill. Purkinje cells were recorded extracellularly and simple and complex spikes were discriminated. Right forelimb displacement, biceps and triceps EMG activity, as well as treadmill velocity, were also monitored. In some animals pressure measurements of the contact of the footpad with the treadmill were obtained. Cells were studied during both "normal" and perturbed locomotion. The perturbation consisted of a braking of the treadmill at different phases in the step cycle. Histograms of the simple and complex spike activity, and averages of the right forelimb displacement, biceps, and triceps EMG activity and treadmill velocity were constructed. The complex spike activity of 163 Purkinje cells was averaged through a minimum of 50 sweeps in either normal and/or perturbed locomotion. Statistical analysis revealed that the probability of the climbing fiber afferent discharge in 54% of the cells (36/67) studied during normal locomotion was significantly modulated with the step cycle. For most Purkinje cells the onset of the increase in climbing fiber afferent discharge was coupled to triceps activity and the onset of stance phase. A group of cells exhibited complex spike discharge in association with biceps onset and swing. These observations suggest that complex spike discharge occurs preferentially at the phase transition periods in the step cycle when the trajectory of the forelimb changes from swing to stance or stance to swing. During treadmill braking 51% of the cells exhibited complex spike modulation (70/137). A number of different patterns of climbing fiber afferent modulation occurred. The most common pattern was an increase in complex spike discharge with the resumption of the treadmill movement and locomotion. Analysis of the time of these periods of increased climbing fiber activity suggests that, although in some cells the response is coupled to the treadmill onset, in other cells the modulation occurs at longer latencies. Subsequent analysis aligning the EMG, displacement, and treadmill velocity signals with the times of the climbing fiber afferent discharge suggested some responses were coupled to the reinitiation of the locomotor cycle. The second most common pattern was an increase in climbing fiber afferent discharge at the onset of the perturbation. Also, in some cells, complex spike discharge decreased during the period in which the step cycle was arrested.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of antibodies to human T-lymphotropic virus type III by using a synthetic peptide of 21 amino acid residues corresponding to a highly antigenic segment of gp41 envelope protein

A peptide of 21 amino acids with the sequence Arg-Ile-Leu-Ala-Val-Glu-Arg-Tyr-Leu-Lys-Asp-Gln-Gln-Leu-Leu-Gly-Ile-Trp- Gly-Cys - Ser encoded by a segment in the env gene of human T-lymphotropic virus type III (HTLV-III), corresponding to amino acids 586-606 of the precursor envelope glycoprotein, has been synthesized by the Merrifield solid-phase method. Combined serological and chemical analyses of this peptide and related peptides have revealed the importance of certain amino acid residues in the antigenic determinant of the relevant peptide. Enzyme immunoassay (EIA) employing this peptide as an antigen adsorbent was shown to reproducibly detect antibodies in sera of patients with HTLV-III infection. This assay provided positive results with all sera that were reactive with gp41 envelope protein of HTLV-III in electrophoretic immunoblot analysis. Thus far, no false-positive sera have been encountered in control populations. Our EIA with this peptide as the coating antigen is shown to have advantages over that with the whole HTLV-III virus as an immunoadsorbent.

Cytochemical and ultrastructural changes in aflatoxin-induced injury to rat liver cells

Young male Sprague-Dawley rats were injected intraperitoneally with a single dose of aflatoxin B1 (AFB1, 3 mg/kg). At 3, 6, 12, and 24 hours and 1, 2, and 5 weeks, the rats were killed and liver samples were taken for examination of sequential ultrastructural changes and localization of acid phosphatase (AcPase), thiamine pyrophosphatase (TPPase) and glucose-6-phosphatase (G6Pase) activity. At 3-6 hrs of AFB1 treatment, the nucleoli became compacted and the network forms of nucleolonema disappeared. Parallel arrays of rough ER encountered in normal liver cells became deranged. Smooth ER increased to form groups of SER anastomosis or vesicles near the golgi area. At 12-24 hours, disruptions of nucleoli, ER systems, and polysomes became more evident. Parallel arrays of ER membranes, forming whorls in the cytoplasm as well as in the cytoplasmic patches (CP), were G6Pase-positive, although the CP were AcPase-negative. The TPPase reaction in bile canaliculi was frequently diminished, but was present in some measure in the Golgi saccules. By 1-2 weeks, most of the injured cells had recovered gradually. The CP disappeared and parallel arrays of RER were observed again in most parenchymal cells. At 5 weeks, the appearance of the nucleoli was normal, as was that of the other organelles. We concluded that the hepatic parenchymal cells had serious lesions at 12 and 24 hours of AFB1 treatment and then recovered nonsynchronously. The response, resistance, and ability to recover from the toxicity of AFB1 varied among the parenchymal cells. The three marker enzymes persisted throughout all regimens of AFB1 treatment.

A cytochemical study of acid phosphatase, thiamine pyrophosphatase and horseradish peroxidase in the Golgi-GERL complex of hepatoma ascites cells

Data from studies of ascitic cells of Chang hepatoma have shown that acid phosphatase (ACPase) can be localized simultaneously within the trans portion of the Golgi apparatus and in tubules of the Golgi-endoplasmic reticulum-lysosome (GERL) system. Reaction products of thiamine pyrophosphatase (TPPase) were also present consistently within trans elements of the Golgi apparatus and within GERL tubules. These new findings indicate that a close physiological association may exist between the Golgi apparatus and GERL, a concept that is consistent with previous observations of fibroblasts. When horseradish peroxidase (PO) is injected intraperitoneally into ascites-bearing rats and the ascitic cells withdrawn at different time intervals, PO could be localized within vesicles and tubules in the GERL region but could not be detected within the Golgi apparatus. Bulk-phase endocytosis requires a long time and a high concentration of PO to occur. The presence of PO within GERL indicates that this organelle may play a role in transporting or processing of certain exogenous proteins.