Migration of Salmonella serotypes Heidelberg and Enteritidis in previously frozen chicken breast meat.

Salmonella spp. have been shown to migrate to the internal regions of meat cuts. Storage conditions and the presence of proteolytic microbiota can influence this process. Our study assessed the impact of storage time, temperature, and the presence of proteolytic psychrotrophic bacteria on migration. Samples of previously frozen chicken breast with skin and bone were then sterilized using gamma ray irradiation and a cobalt-60 source (11 KGy) and them were inoculated with cultures of S. Enteritidis, S. Enteritidis and psychrotrophs, S. Heidelberg, or S. Heidelberg and psychrotrophs. Inoculated samples were stored for 6, 12, 24, 48, or 168 h at 2, 7, or -30 °C. After treatment, samples were divided into similar-sized segments and bacterial counts were determined in different regions (A - superface, B - intermediate region, and C - internal region). S. Heidelberg and S. Enteritidis both demonstrated successful internal migration for each time, temperature, and bacterial combination (p < 0.05). Our data revealed that Salmonella migration proceeded for 24 h, but slowed at 48 h (p < 0.05). S. Enteritidis with psychrotrophs showed a low amount of internal migration (p < 0.05). We therefore conclude that Salmonella spp. are able to migrate into the internal regions of meat cuts in a short period of time, even at low temperatures. The presence of proteolytic psychrotrophs inhibits the migration of S. Enteritidis.

Histological alterations in gills of Macrobrachium amazonicum juveniles exposed to ammonia and nitrite.

Aquaculture has shown great growth in the last decades. Due to the restrictions on water use, production systems are becoming increasingly more intensive, raising concerns about the production water quality. Macrobrachium amazonicum is among the freshwater prawn species with favorable characteristics for production and possibility of intensification. Nitrogen compounds such as ammonia and nitrite affect the health of aquatic organisms since they quickly reach toxic concentrations. These compounds can also cause damage to the gill structure, leading to hypoxia in tissues, affecting acid-base balance, osmoregulation (salt absorption) and ammonia excretion, decreasing the immune capacity of the animal and, in extreme cases, cause death. The aim of this study was to assess histological changes in the gills of Macrobrachium amazonicum juveniles subjected to different concentrations of total ammonia and nitrite. The prawns were subjected to different concentrations of those compounds and their gills were removed and preserved for histological analysis. The gills were assessed for changes according to the Organ Index (Iorg) and, for each change, an importance factor (w) was attributed according to the degree of reversibility and applied according to the degree of extension or frequency of the damage. The damage to the gills in the treatments with 100% mortality, both for ammonia and nitrite, corresponded to the high occurrence of progressive, regressive, circulatory, and inflammation damages. The other treatments (which caused less mortality) had mainly inflammation and regressive damages, whose occurrence increased according to the increase in ammonia and nitrite concentration. The histological analysis confirmed that the higher the total ammonia and nitrite concentrations, the larger the damages caused to the gill structure and that lower nitrite concentrations caused similar damages to those caused by higher total ammonia concentrations, which reflects the lower capacity M. amazonicum has to tolerate nitrite.

Changes in follicular cells architecture during vitellogenin transport in the ovary of social Hymenoptera.

Vitellogenins are the major yolk proteins, synthesized in the fat body, released into the hemolymph and captured by the developing oocytes, but the mechanisms by which these proteins cross the follicular cell layer are still poorly understood. This study describes the actin distribution in follicular cells during vitellogenin transport to the oocyte in social Hymenoptera represented by bees Apis mellifera and Melipona quadrifasciata, the wasp Mischocyttarus cassununga and the ant Pachycondyla curvinodis. In oocytic chambers of vitellogenic follicles, vitellogenin was found within the follicular cells, perivitelline space and oocyte, indicating a transcellular route from the hemolymph to the perivitelline space. The cortical actin cytoskeleton in follicular cells underwent reorganization during transport of vitellogenin across this epithelium suggesting that in the ovary of social hymenopterans, vitellogenin delivery to oocytes requires a dynamic cytoskeletal rearrangement of actin filaments in the follicular cells.

Production of potential vaccine against Dermatobia hominis for cattle.

The present study aimed to detect and characterize antigenic proteins and to assess their activity as preventive vaccines against dermatobiosis. Polyclonal antibodies were produced against three larval instars (L(1), L(2), L(3)), and their antigenic proteins were assessed for reactivity. Polyclonal antibodies produced in animals immunized with extracts were analyzed, and L(3)-derived antibodies showed proteins with better antigenic responses. The study of reactivity using immunodetection showed that the 50-kDa protein had the highest antigenicity. This protein was purified and subjected to mass spectrometry, and the sequences obtained were compared with those in the databases available. No similarities were found with existing sequences. Subsequently, large quantities of purified protein were used to immunize cattle. Vaccine effectiveness was evaluated by comparing the number of cutaneous nodules formed in the control group and immunized animals. The antigen produced proved a promising candidate for vaccine production, with 90.67 % efficacy. Immunohistochemistry of antigen-antibody reaction in larval sections showed epitopes all over larval tissues.

Post-embryonic development of the antennal sensilla in Melipona quadrifasciata anthidioides (Hymenoptera: Meliponini).

The sensilla are sensory organs formed by cuticular and cellular structures specialized in reception of chemical and physical stimuli from the environment and transmission to the insect's central nervous system. In function of the great concentration of sensilla, the antennae are the main organs for interaction between bees and with the environment. This work studied the presence of antennal sensilla in the different phases of pupal development of the stingless bee Melipona quadrifasciata anthidioides by means of scanning electron microscopy and light microscopy. The results showed that antennal sensilla begin their development in the transition of the prepupae to the white-eyed pupae and finish it in the pigmented-body pupae phase. The antennal sensilla were exposed to the environment in the black-eyed pupae when the old cuticle is completely digested, suggesting that only in the final pupal phases can these bees perceive the environmental stimuli.

Comparação histológica entre a região cervical esôfago de cateto (Tayassu tajacu LINNAEU – 1758) e de javali (Sus scrofa scrofa LINNAEU - 1758 ) / Histological comparison between the esophagus' cervical region of collared peccary (Tayassu tajacu LINNAEU - 1758) and of wild board (Sus scrofa scrofa linnaeu - 1758)

Apesar da criação de javalis e catetos estarem aumentado no Brasil devido à sua importância econômica, poucas informações histológicas estão disponíveis sobre ambas as espécies. O objetivo deste trabalho foi descrever a histologia da porção cervical do esôfago de catetos e javalis, comparando-as. Foi observado que esta porção do esôfago do javali é constituído de mucosa sem a muscular da mucosa, submucosa com grande quantidade de glândulas, túnica muscular com apenas músculo estriado esquelético e serosa. No esôfago de catetos, há presença de mucosa com muscular da mucosa, submucosa aglandular, túnica muscular e serosa. Portanto, pode-se afirmar que a porção cervical do esôfago do javali e do cateto diferem em várias características histológicas.

Although raising collared peccaries and wild boars in Brazil is increasing due to the growing economic importance of that activity, only a few histological data are available on both species. The objective of this paper was to describe the histology of the cervical portion of the esophagus of collared peccaries and wild boards by comparing them. It has been observed that this portion of a wild board's esophagus is composed of a mucosa without muscularis mucosæ, sub-mucosa with a large number of glands, muscular tunica with only skeletal striated muscle and serosa. On the other hand, in collared peccaries' esophagus there is mucosa with muscularis mucosæ, sub-mucosa without glands, muscular tunica and serosa. Therefore, it would be correct to say that the cervical portion of a wild boar's esophagus and that of a collared peccary have many different histological characteristics.

Aspectos histopatológicos da reação inflamatória em bovinos parasitados por larvas (L3) de Dermatobia hominis (Linnaeus Jr., 1781)

O presente trabalho foi desenvolvido nos Laboratórios de Citologia e Histologia da UFPR, durante o período de setembro de1999 a agosto de 2000. O objetivo do trabalho foi avaliar, por meio da histologia, a reação inflamatória em biópsias de pele debovinos parasitados por larvas (L3) de Dermatobia hominis (Linnaeus Jr., 1781). A presença da larva (L3) de D. hominis na peledos bovinos gerou um processo inflamatório crônico, caracterizado por infiltração de células mononucleares (que incluíammacrófagos, linfócitos, plasmócitos) e células epiteliais resultantes da destruição tecidual e fibrose. As amostras das lesõescutâneas continham, na derme profunda e subcútis, extensas áreas de cavitação revestida por abundante número de neutrófilosdegenerados e tecido de granulação densamente infiltrado por linfócitos, plasmócitos, macrófagos.