Chilling injury and changes in adenosine triphosphate of cotton seedlings

Young Gossypium hirsutum L. seedlings chilled at 5° showed a continual decrease in ATP concentration with time of chilling. Chilled plants returned to optimum conditions were able to restore the initial ATP concentration when chilled only 1 day, but not when chilled 2 days. The decrease in ATP with chilling was prevented by hardening the seedlings at 15° for 2 days (14-hr-day-length) immediately before chilling. The ATP level of hardened plants was higher than of unhardened plants. When hardened plants were chilled at 5°, the ATP level increased in the leaves but decreased in the roots.     

A New Saurian Malarial Parasite Plasmodium balli from Panama

SYNOPSIS. Plasmodium balli sp. nov. is described from Anolis lionotus and A. poecilopus of central Panama.
Large, elongate gametocytes and segmenters containing up to 100 merozoites are produced by P. balli. Proerythrocytes and normoblasts are more commonly parasitized than erythrocytes. Pigment is uncommon, but when present consists of a minute dot. Hypertrophy, distortion and lysis of host cell nuclei may result from parasitization of immature blood cells by gametocytes, while enucleated host cells are common.     

The Control of Color in Mammals

SYNOPSIS. Recent advances in the biology of mammalian pigmentationare reviewed.Particular attention is given to emerging informationon the integration of pigmentary events occurring at differentlevels of biological organization within mammalian skin andhair. The structural and functional significance of keratinocytesand melanocytes as components of mammalian epidermal melaninunits is viewed from this perspective. New evidence on the natureof genetic, developmental, endocrine, and radiation influenceson performance of melanocytes and the establishment of pigmentarypatterns is summarized.     

Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae

Summary Cell-free extracts capable of acetylene reduction and cyanide reduction have been prepared from heterocystous (Anabaena cylindrica) and non-heterocystous (Plectonema boryanum 594) blue-green algae. Extracts from Anabaena were obtained from cultures grown in blulk under aerobic conditions, while the Plectonema cultures were grown in bulk on nitrate-nitrogen, then washed free from nitrate and sparged with A/CO₂ for 40 h after which time maximum nitrogenase activity was detected. The nitrogenases of both algae are similar and resemble in many respects nitrogenases from bacteria and legumes. Activity is located primarily in a 40,000xgx15 min supernatant fraction and the rate of C₂H₂ reduction observed is about 10 per cent of whole cell activity. ATP and a source of reducing power (Na₂S₂O₄) are required for efficient functioning of the enzyme. ATP-dependent hydrogen evolution occurs, the extracts are cold labile and highly sensitive to oxygen and the oxygen inhibition is irreversible.     

Differentiating Type i and Type ii Alveolar Cells in Rat Lung by OsO4NaI Staining

The fixing-staining mixture consisted of 1 part of 2% aqueous OsO₄ and 3 parts of 3% Nal in distilled water. Fresh lungs were cut into 2 mm slices and immersed in this solution for 24 hr at room temperature. Controls were fixed in buffered OsO₄ alone. Selective staining of type II alveolar cells was shown by the OsO_t-NaI mixture but was absent in the controls. No additional staining of the sections was required, and the selectivity was readily observable in either paraffin or Araldite sections by light microscopy and in Araldite sections by electron microscopy     

Saurian Malarial Parasites in Eastern Panama

SYNOPSIS Plasmodium gonatodi sp. nov. is described from Gonatodes albogularis fuscus of eastern Panama. It is characterized by elongate gametocytes and polymorphic schizonts containing 12-46 nuclei when apparently mature. Both proerythrocytes and erythrocytes are commonly parasitized, host cells are hypertrophied and distorted, and their nuclei are displaced. Prematuration sexual stages may be irregularly shaped and larger than mature gametocytes.
Plasmodium diploglossi Aragão and Neiva , 1909 is reported from Mabuya mabouya in eastern Panama, and Plasmodium morulum sp. nov. is described from this host. P. morulum usually parasitizes immature erythrocytes, and is characterized by lenticular or oval to round gametocytes, and schizonts with 14-40 nuclei usually arranged in a globular mass. Host cells are slightly hypertrophied and distorted, and their nuclei are usually displaced. Inoculation of infected blood into clean hosts produces numerous schizonts in white cells as well as in the erythrocyte series.
Pigment in both P. gonatodi and P. morulum , if present, consists of a few minute dark dots which do not meet the polarized light test for hemozoin.     

Lipolytic Esterases in Staphylococci

Staphylococci split a wide range of lipid substrates by production of an enzyme complex with two main components (i) a lipase acting optimally on fat-soluble glycerides, and (ii) an esterase acting optimally on water-soluble esters. The action is dependent upon carbon chain length, interfacial dispersion, solubility, and pH of substrate and end products. The esterase is less susceptible to organophosphorus inhibitors than mammalian esterases. There is no apparent correlation between lipolysis and markers of pathogenicity such as production of coagulase and toxin, but the possession of a flexible lipolytic mechanism might account for the persistence of staphylococci in the fatty secretions of mammalian skin.     

SPORADIC ACUTE GLOMERULONEPHRITIS IN ADULTS

Nineteen adults who had acute glomerulonephritis were reviewed with respect to the clinical course and long-term follow-up. The age range was from 17 to 55 years. Only one patient died during the acute episode. In 11 cases, onset occurred between November and January and 15 of the patients had a known respiratory tract infection three to 30 days before the onset. The most important symptoms noted were weight gain, edema, dyspnea, oliguria and red or smoky urine. The most prominent physical signs were elevated blood pressure, edema, abnormalities in the chest and fever of over 100° F. Fifteen patients showed roentgen evidence of pulmonary vascular congestion, pleural effusion, cardiomegaly, pneumonia or a combination of these abnormalities. All the patients had proteinuria and red blood cells in the urine, and half of them had red blood cell casts. Azotemia, when present, subsided in 9.4 days. The average diastolic pressure was 105 mm. of mercury and the mean fall was 26 mm. in 23.5 days. At six months, nine of the 13 patients still being observed continued to show proteinuria or microscopic hematuria (seven showed both). A late follow-up of ten patients showed one to have significant hypertension and one to have early functional impairment and inconstant proteinuria. In these cases the average blood pressure was 140/91 mm. as compared with 119/74 mm. at the time of discharge.Sporadic glomerulonephritis in adults presents essentially the same pattern as it does in children. Urinary abnormalities may persist for months or even years, and neither the present series nor those reported by others clearly reveal the ultimate prognosis.     

Rates of Dissolution of Tolbutamide Tablets

An investigation was made of the pharmaceutical properties and the in vitro dissolution rates of 18 commercially available brands of tolbutamide tablets, all of which met the limits set by the Food and Drug Regulations for tablets sold in Canada.A marked variation in dissolution rates was found, which bore no relation to the official disintegration time. These wide variations in dissolution rate point to a need for (a) a comprehensive study of the in vivo effects of different tolbutamide tablets, and (b) an official test that sets limits for the rate of dissolution of tolbutamide tablets, in addition to the one that places limits on disintegration time.