Morphological Studies in the Genus Nocardia. Iii. The Morphology of Young Colonies

Abstract

This study waz supported in part by a grant from the General Research Fund of the University of Kansas. 168 12 hrs. Short rods elongating and bending. 24 hrs. Young colonies composed of long fragmented hyphae. Few branches produced.Fragmentation of types 1 and 2 begins in center of small colony. 36 hrs. Large colonies consisting of long hyphae with few branches. 72 hrs. Large dense colonies which fragments in center, peripheral hyphae continue to grow, branch and fragment STOCK No. 15. Nocardia sp. 12 hrs. Refractive rods germinating by elongation. 24 hrs. Young colonies formcd by fragmentation into long hyphae. Few branches and fragmentation is of types 1 and 2. 36 hrs. Colonies formed by long unbranched hyphae continue to elongate a t the edges.Fragmentation produces shorter cells. 70 hrs. Circular colonies, dense in center, radiating, nonbranched hyphae around periphery. STOCKNo. 16. Nocardia sp. FIGURES 17, 18, 19 and 20. 12 hrs. Bent rods, some forming short branches. 24 hrs. Small colonies consisting of fragmented hyphae. 36 hrs. Circular colonies with short fragments in the center. around periphery. 70 hrs. Large circular dense colonies, short bent peripheral hyphae. STOCK No. 57. 12 hrs. Rods elongating and bending, few short branches produced. 24 hrs. Small colonies consisting of sharply bent hyphae in center, with longer curved hyphae around edges. Branches few. Fragmentation of type 1 Nocardia sp. FIGURES 13, 14, 15 and 16. Fragmentation frequently of type 1. FIGURES 21, 22, 23, and 24. Few short branches produced. Hyphae mostly unbranched Jensenia canicruria Risset and Moore. FIGURES 25, 26,27 and 28. 72 hrs. Small compact colonies with fragmented center and short peripheral hyphae. STOCK No. 76. 12 hrs Rods elongating, bending, and producing short branches. 24 hrs. Small colonies with secondary branching, type 2 fragmentation beginning in center. 36 hrs. Small colonies with hyphae at periphery with few branches, fragmentation in center. 72 hrs. Small compact colonies with short fragments in the center, short peripheral hyphae produced. STOCK No. 78. N . corallirta (Bergey et al.) Bergey et al. FIGURES 61, 62, 63, and 64. 12 hrs. Short elongating rods, some bending. 24 hrs. Branched hyphae forming small colonies. Fragmentation of type 2 beginning in center. 36 hrs. Colonies consist of fragmented central hyphae, peripheral hyphae sparsely branched. 72 hrs. Central hyphae fragmented to short rods, arranged a t angles. Peripheral hyphae characteristically branched. STOCK No. 79. N . convoluta (Gray and Thornton). FIGURES 141, 142, 143, and 144 12 hrs. Curved elongating rods, occasional short branches produced. 24 hrs. Rods elongating and branching. Branches are produced so as to suggest dichotomous branching. 36 hrs. Circular colonies with curved branching hyphae a t periphery. 70 hrs. Large colonies with dense center, long branched hyphae at periphery. STOCK NO. 87. 12 hrs. Short rods not germinating. 24 hrs. Rods elongating with short branches. 36 hrs. Rods forming small branched colonies which are fra...

On the Nature of Cytoplasmic Inclusions of Nocardia rubra

“…It was later reported by Lieske (1921) that fragmentation occurred after separation of the protoplasm, without prior septation, after which individuals separated. More recently (Bisset & Moore, 1949 ;McClung, 1950) the problem of the existence of septa in the actinomycetes and the genus Nocardia in particular, has been re-examined. Bisset & Moore (1949) reported that multicellularity was a characteristic of the genus Nocardia, but McClung (1950) was unable to demonstrate septa in N .…”

“…In recent years several investigators have studied the cytology of members of the genus Nocardia (Bisset tk Moore, 1949;McClung, 1950;Morris, 1951;Webb, Clark & Chance, 1954;Webb & Clark, 1957;Hagedorn, 1959a, b). Although their studies have been extensive, frequently the findings of these authors have been conflicting.…”

Nuclear Morphogenesis During the Developmental Cycles of Some Members of the Genus Nocardia

“…Morris (1951) described a complex life cycle, including several nuclear fusion and reductional division stages, for members of the genus Nocardia. His report, undocumented with micrographs, in light of the work of others (McClung, 1950(McClung, , 1955Webb et al 1954;Webb & Clark, 1957;and Hagedorn, 1959a, b ) and the present observations, lead the author to discount the complex life cycle he described. Webb et al observed discrete nuclei in most phases of the growth of Nocardia corallina.…”

“…While earlier reports described nocardial nuclear morphogenesis, the results of these investigations were conflicting (McClung, 1950(McClung, , 1955; Morris, 1951 ; Webb, Clark & Chance, 1954; Webb & Clark, 1957; Clark & Frady, 1957;and Hagedorn, 1959a, b ) and many of the staining techniques used were unsuitable (Adams & McClung, 1962 b). The discovery of genetic recombination in the Nocardiae (Adams & Bradley, 1963) necessitates clarification of the nature of nocardial nuclear morphogenesis to help understand genetic interactions among the group.…”

ULTRASTRUCTURE OF NOCARDIA ASTEROIDES AS REVEALED BY ELECTRON MICROSCOPY

“…Extensive cytological studies on Nocardia by light microscopy have been reportec by several workers (1,2,17,27,33), but there have been very few accounts of electror microscopic observations on these organisms, particularly applying thin sectioning techniques. To our knowledge, no detailed study of N. asteroides, using present-day techniques of electron microscopy, has been reported to date.…”