Studies on Antifungal Properties of Essential Oil of Trachyspermum ammi (L.) Sprague

The essential oil from the fruits of Trachyspermum ammi exhibited toxicity at 800 ppm against Aspergillus flavus and A. niger, the nature of toxicity being cidal. The toxicity of the oil was not affected by autoclaving, temperature treatment and storage upto 365 days. The oil killed the test fungi within 50 seconds; withstood heavy inoculum density and was inhibitory to as many as 21 fungi at its minimum inhibitory concentration. However the seeds of Arachis hypogea whentreated with oil at 5000 ppm and stored for 12 months did not show the appearance of any fungi indicating thereby the grain protectant activity of the oil. The oil was characterized by various physico chemical properties and on chemical investigation Thymol and p-cymene were isolated as antifungal principles of the oil exhibiting toxicity against the test fungi at 1000 ppm.     

Mode of uptake of insoluble solid substrates by microorganisms. II: Uptake of solid n-alkanes by yeast and bacterial species

Using two species of yeast and one of bacterium, evidence has ben obtained which indicates that the microbial uptake of solid alkane powders occurs primarily through a substrate solubilization mechanism. EDTA, a strong inhibitor of hydrocarbon solubilization by the cells, inhibited the growth of these organisms on alkane powder; the inhibition could be removed vai a supply of artificially solubilized alkane. One of the yeast strians, which was a mutant incapable of growing on solid alkane powder and liquid alkane, could grow very well on artifically solubilized alkanes. It was demonstrated that the solid alkane solubilization rate during microbial growth could satisfactorily account for the maximal alkane uptake rate actully observed during growth. The specificity of solubilization for the solid alkane used as the growth substrate was demonstrated.     

Changes in Muscarinic Binding in Distant Brain Regions Showing Neuronal Losses After Folic Acid Injections into the Substantia Innominata

Injection of folic acid (FA) into the nucleus substantia innominata (NSI) was found to decrease [3H]quinuclidinyl benzilate ([3H]QNB) binding in the frontal cortex, pyriform cortex, amygdala, and the NSI itself without changing the KD. Binding in the thalamus, caudate nucleus, hippocampus, and substantia nigra was not affected. [3H]Flunitrazepam binding was unchanged in all eight regions studied. Previous work indicates FA injections into the NSI produce epileptiform activity and cause loss of GABAergic and possibly other neurons in the frontal and pyriform cortices, the amygdala, and thalamus. The reductions of [3H]QNB binding in the first three of these regions are interpreted as indicating that many of the neurons lost are cholinoceptive, a finding that supports the previous hypothesis that activation of cholinergic projections from the NSI is an important part of the mechanism of cell loss in these regions.     

Population biology of Avena

Summary Surveys for polymorphisms in natural populations of A. barbata sampled in California grasslands had provided evidence for widespread monomorphism and rather localized polymorphic areas in the north coastal and San Francisco regions, based on a set of morphological and isoenzymatic marker loci. Since this species, like many other annuals, was introduced from the Mediterranean region during the Spanish mission period, a comparative study of the Canadian-Welsh collections of Avena species from the Mediterranean region was undertaken using various plant characters and starch gel electrophoresis to analyze variants for esterase, phosphatase and peroxidase systems. A total of 96 samples including 73 of A. barbata and 23 of A. hirtula were studied and the results were scored to compute the polymorphism indices. In both species, only 10 to 15 percent sites showed any significant degree of polymorphism of which a majority seemed to originate from localized regions in Italy and Turkey; a part of this observed lack of within-sample variation might be the result of small sample size. In general, the patterns of variation in A. barbata from the California surveys and the present analyses seemed to be very similar and raised some interesting questions on (a) the colonizing history of introduced materials (b) the factors underlying such marked patterns of geographical variation, and (c) the current evolutionary changes occurring in these two broad, disjunct areas of species distribution.

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Zusammenfassung Untersuchungen der Polymorphismen in natürlichen Populationen von A. barbata im kalifornischen Weideland hatten einerseits zum Nachweis eines weit verbreiteten Monomorphismus und andererseits streng lokalisierter polymorpher Bereiche in der nördlichen Küsten- und San Francisco-Region geführt, wobei eine Anzahl morphologischer und isoenzymatischer Markerloci zugrunde gelegt wurde. Da diese Art, wie viele andere Annuelle auch, während der spanischen Missionsperiode aus der Mittelmeerregion eingeführt wurde, wurde eine vergleichende Untersuchung der Canadian-Welsh-Sammlungen von Avena-Arten aus der Mittelmeerregion anhand verschiedener Merkmale der Pflanzen und der Stärkegelelektrophorese-Untersuchung auf Esterase-, Phosphatase- und Peroxydase-Systeme durchgeführt. Es wurde eine Gesamtheit von 96 Stichproben, bestehend aus 73 A. barbata und 23 A. hirtula, untersucht und die Ergebnisse zur Berechnung von Polymorphismus-Indices verwendet. In beiden Arten zeigten nur 10 bis 15% der Herkünfte einen signifikanten Polymorphismusgrad. Von ihnen scheint die Mehrzahl von lokalisierten Regionen in Italien und Griechenland abzustammen. Ein Teil des beobachteten Fehlens einer Variation innerhalb der Stichproben könnte eine Folge des geringen Stichprobenumfangs sein. Im allgemeinen scheinen die Variationsmuster der kalifornischen Untersuchungen und die der vorliegenden Analysen von A. barbata sehr ähnlich zu sein. Das führt zu einigen interessanten Fragen nach a) der Besiedelungsgeschichte des eingeführten Materials, b) den Faktoren, die derart auffallenden Mustern der geographischen Variation unterliegen und c) den laufenden evolutionären Änderungen, die in diesen beiden großen, voneinander getrennten Gebieten der Artverteilung auftreten.

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This work was supported in part by a grant from the National Science Foundation (GB 8627).     

The mechanism of sex determination in Rumex acetosella

Summary Cytogenetic studies were made with particular emphasis on the sex-determining mechanism in Rumex acetosella (6 x = 42) and its hybrids (F ₁, F ₂, BC ₁ and BC ₂) with R. hastatulus (synthetic 4 x = 16 = 4 A +4 X = and 4 x = 18 = 4 A + 2 (X Y ₁ Y ₂) = ). Rumex acetosella was almost strictly dioecious with 5050 male and female. Breeding tests revealed that the males were heterogametic. The longest chromosomes (S), usually two, are the sex chromosomes of this hexaploid species. The S chromosomes are homomorphic in both male and female. The sex chromosome: autosome ratios, and the strong epistatic male effect of the S ^M chromosome in the polyploid dioecious species and in the hybrids, are evidence of an X/Y Melandrium type sex-determining mechanism controlled by a single pair of homomorphic sex chromosomes. Thus, the sex chromosome formula of the males was S ^F S ^M and that of females was S ^F S ^F. The present approach is a new method for resolving the sex-determining mechanism in a dioecious species.     

Population dynamics of microfilarial production and eosinophilic levels in slow lorises infected with Breinlia sergenti. Petter (Filarioidea: Dipetalonematidae)

Population dynamics of microfilarial production and eosinophilic levels in slow lorises infected with Breinlia sergenti, Petter (Filarioidea: Dipetalonematidae). International Journal for Parsitology 4: 383388. Observations have been made on microfilarial and eosinophilic levels in slow lorises infected with Breinlia sergenti. Animals given a single inoculation of 100-150 infective larvae exhibited three different patterns of microfilaraemia while superinfected animals showed enhanced microfilarial levels. It appeared that the number of inoculations as well as the interval between inocula are important factors in enhancing microfilarial levels. Two different types of incubation periods were seen, one at 100-120 days and the other at 200 days. The eosinophilic levels were investigated in some of the animals and an attempt was made to correlate these levels with the microfilaraemia. Cortisone injection appeared to promote a vigorous eosinophilia in some of the infected animals tested.     

Immunoglobulin synthesis and glucose-6-phosphate dehydrogenase as cell markers in human lymphoblastoid cell lines

Multiple lymphoblastoid cell lines were established from each of seven Burkitt lymphoma biopsies and from tonsils, removed from four patients with chronic tonsillitis. The cellular origin of the lines was studied using as markers the pattern of immunoglobulins secreted into the medium and the cells' glucose-6-phosphate dehydrogenase (G-6-PD) phenotypes.Lines from the same tonsil biopsy differed from each other by their patterns of immunoglobulin synthesis and G-6-PD phenotypes. All tonsil-derived lines secreted complete immunoglobulins. Newly established lines usually produced several heavy and light chain types, indicating multicellular origin, but the number of components produced decreased during the course of long-term cultivation. G-6-PD phenotypes of lines established from the same tonsil removed from a G-6-PD heterozygote differed—B, A and B/A phenotypes were found. The B/A lines rapidly changed to a single enzyme phenotype (B or A) when maintained in culture.The immunoglobulin and G-6-PD phenotypes in lines derived from Burkitt lymphomas differed from those of tonsil lines in several respects: (1) Some lines produced no immunoglobulins; (2) in immunoglobulin-synthesizing lines, the patterns of heavy and light chain production were more restricted than in tonsil lines; (3) after some months in culture, a uniform pattern of immunoglobulin synthesis was found in all lines derived from the same tumour; (4) lines from G-6-PD heterozygotes had the same single enzyme phenotypes as were found in the tumours.The data strongly suggest that most lines from Burkitt lymphomas are derived from the tumour clones and that most tonsil-derived lines have multicellular origin.     

Suppression of Two Missense Alleles of the TRP5 Locus of SACCHAROMYCES CEREVISIAE

A suppressor SUP101 of alleles trp5-67 and trp5-18 of the trp5 locus of Saccharomyces cerevisiae is described. The two suppressible mutations have been previously classified as missense. The suppression does not result from a physiological bypass of the tryptophan synthetase-catalyzed reaction, since the suppression is allele-specific. IU alleles trp5-70, tryp5-95, and trp5-102; IA alleles trp5-81, trp5-101, and trp5-103; and the ochre alleles trp5-33 and trp5-48 are not suppressed by SUP101. SUP101 does not suppress ochre alleles ade2-1, his5-2, arg4-17, lys1-1, amber alleles trp1-1, tyr7-1, or unclassified alleles at a number of other loci. These results indicate SUP101 is a missense suppressor. Growth on tryptophanless media is dependent upon gene dosage of both the suppressor and the suppressible alleles. Only the diploids homozygous both for the suppressor and suppressible alleles produce growth equivalent to growth of the haploids bearing a suppressible allele and the suppressor. Suppressor-bearing strains grow poorly even on tryptophan-supplemented media. In more than 100 asci analyzed partial growth inhibition on the complete medium always segregated with the suppressor.