Scanning electron microscopy of fixed, frozen, and dried protozoa.

Selected protozoa were examined with a scanning electron microscope. The natural shape of the body and surface organelles were revealed. Chemical fixation and freeze-drying techniques described here permit a new approach to the study of protozoa.

Ultrastructure of feeding in the karyorelictean ciliate Tracheloraphis examined by scanning electron microscopy.

The karyorelictean ciliate Tracheloraphis is considered to be among the most primitive of the extant ciliates based on both nuclear and somatic characters. These organisms lack the elaborate oral ciliation present in most ciliates. Their mode of ingestion is a type of phagocytosis through a non-ciliated region, the glabrous stripe, which runs the length of the cell. This type of ingestion is reminiscent of feeding in amoebae and some flagellate groups. It is possible that ciliate oral structures evolved within the karyorelictean ciliates from an ancestor resembling Tracheloraphis. We studied the ingestion process in a Tracheloraphis species from the Chesapeake Bay using scanning electron microscopy. The results indicate that the anterior terminus of the organism is not involved in the actual ingestion process, only the glabrous stripe. There is some interaction between the food particle and the surface of the stripe, possibly mediated by a substance secreted by the underlying extrusomes. The somatic cilia do not appear to be involved. The stripe invaginates at the ingestion site engulfing the particle. The cell becomes greatly distended at this site, but neither the anterior nor posterior terminus is affected.

A new macrosystem for the phylum Ciliophora doflein, 1901.

A new macrosystem for the phylum Ciliophora is described. It is based primarily on the concept of the structural conservatism of the cortical fibrillar structures. Three subphyla, the Postciliodesmatophora, Rhabdophora, and Cyrtophora, are described. These three subphyla are divided respectively into the following classes: (1) the Postciliodesmatophora, into the Karyorelictea and Spirotrichea; (2) Rhabdophora, into the Prostomea and the Litostomea n, nov.; and (3) Cyrtophorea, into the Nassophorea n. nov., Phyllopharyngea, Coipodea, and Oligohymenophorea. The subclass divisions of these eight classes are briefly discussed. Problem areas are indicated where further research will test the relationship proposed by this new macrosystem.

Protist kinetids: structural conservatism, kinetid structure, and ancestral states.

The protist kinetid is considered a conservative indicator of phylogenetic relationship. This conclusion is supported by the apparently inverse relationship between the conservation of structure and its level in the organizational hierarchy. A comparative examination of features of protist kinetids indicates that pattern is strongly conserved; within and among flagellate taxa there is more variability in pattern than within the ciliates. It is concluded that the ancestral flagellate kinetid is a pair of orthogonally oriented kinetosomes having one striated rootlet and at least one microtubular ribbon. The ancestral kinetid of the ciliates is also a dikinetid structure, though represented by a paired set of parallel kinetosomes, probably similar to that found today in karyorelictid ciliates, presumptive descendants of the ancestral stock.

An update on the systematics of the phylum Ciliophora doflein, 1901: the implications of kinetid diversity.

Recent classifications of the phylum Ciliophora are compared with the system proposed by Small and Lynn in 1981 and revised in 1985. The classes COLPODEA, PHYLLOPHARYNGEA, OLIGOHYMENOPHOREA and NASSOPHOREA sensu Small & Lynn are considered monophyletic by a number of researchers. The classes LITOSTOMATEA and PROSTOMATEA sensu Small & Lynn are not as well accepted. Some divergence of opinion arises in recognition of the categories included in the classes KARYORELICTEA and SPIROTRICHEA sensu Small & Lynn, in which the great diversity of cortical ultrastructure is still not recognized in the taxonomy. Numerous minor groups, for example the phacodiniids, plagiopylids and schizocaryids, present taxonomic problems that may not be solved by ultrastructural examination. This is also true of the subphyletic divisions where there are substantial differences of opinion about relationships among the classes.

Loneliness in Black elderly.

Loneliness was investigated in three groups of Black elderly people. Groups consisted of Married, Widowed, and Never Married. The deJong-Giervald Loneliness Scale was used to measure loneliness on the none subscales that make up the instrument. These subscales measured the extent: of feelings of deprivation concerning a partner (L1); of feelings of emptiness or lack of companionship (L2); of feelings of abandonment (L3); of rationalization of personal loneliness (L4); of self-pity (L5); to which loneliness is perceived as permanent (L6); to which is perceived as temporary (L7); to which it is perceived that loneliness can be solved by one's own activities (L8); of resignation to loneliness (L9). Significant differences between scores were found in only two subscales. These were numbers L4 and L6. On each of these subscales, Widowed and Other Married groups, which were mostly composed of women, had the lowest mean scores. This reflects the likelihood that these groups use rationalization to cope with the negative effects of loneliness, and this is sex-specific. Findings also reflect that unmarried Black elderly, especially females, may feel hopeless about being lonely. Recommendations made for further studies include using larger and more heterogeneous samples as well as different ethnic groups.

Influence of water temperature, salinity, and pH on survival and growth of toxigenic Vibrio cholerae serovar 01 associated with live copepods in laboratory microcosms.

The influence of water temperature, salinity, and pH on the multiplication of toxigenic Vibrio cholerae serovar O1 cells and their attachment to live planktonic crustaceans, i.e., copepods, was investigated by using laboratory microcosms. By increasing water temperatures up to 30 degrees C, a pronounced effect on the multiplication of V. cholerae was demonstrated, as was attachment of the cells to live copepods. These were measured by culturable counts on agar plates and direct observation by scanning electron microscopy, respectively. Of the three salinities examined (5, 10, and 15%), maximum growth of V. cholerae and attachment to copepods occurred at 15%. An alkaline pH (8.5) was optimal both for attachment and multiplication of V. cholerae, as compared with pH 6.5 and 7.5. It is concluded that conditions affecting attachment of V. cholerae serovar O1 to live copepods observed under laboratory conditions may also occur in the natural estuarine environment and, thereby, are significant in the epidemiology of cholera.

Ecological relationships between Vibrio cholerae and planktonic crustacean copepods.

Strains of Vibrio cholerae, both O1 and non-O1 serovars, were found to attach to the surfaces of live copepods maintained in natural water samples collected from the Chesapeake Bay and Bangladesh environs. The specificity of attachment of V. cholerae to live copepods was confirmed by scanning electron microscopy, which revealed that the oral region and egg sac were the most heavily colonized areas of the copepods. In addition, survival of V. cholerae in water was extended in the presence of live copepods. Attachment of viable V. cholerae cells to copepods killed by exposure to -60 degrees C was not observed. Furthermore, survival of V. cholerae was not as long in the presence of dead copepods as in the live copepod system. A strain of Vibrio parahaemolyticus was also seen to attach to copepod surfaces without effect on survival of the organism in water. The attachment of vibrios to copepods was concluded to be significant since strains of other bacteria, including Pseudomonas sp. and Escherichia coli, did not adhere to live or dead copepods. Attachment of V. cholerae to live copepods is suggested to be an important factor of the ecology of this species in the aquatic environment, as well as in the epidemiology of cholera, for which V. cholerae serovar O1 is the causative agent.