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MBio Jun 2024Transmission of by fleas depends on the formation of condensed bacterial aggregates embedded within a gel-like matrix that localizes to the proventricular valve in the...
UNLABELLED
Transmission of by fleas depends on the formation of condensed bacterial aggregates embedded within a gel-like matrix that localizes to the proventricular valve in the flea foregut and interferes with normal blood feeding. This is essentially a bacterial biofilm phenomenon, which at its end stage requires the production of a exopolysaccharide that bridges the bacteria together in a cohesive, dense biofilm that completely blocks the proventriculus. However, bacterial aggregates are evident within an hour after a flea ingests , and the bacterial exopolysaccharide is not required for this process. In this study, we characterized the biochemical composition of the initial aggregates and demonstrated that the yersinia murine toxin (Ymt), a phospholipase D, greatly enhances rapid aggregation following infected mouse blood meals. The matrix of the bacterial aggregates is complex, containing large amounts of protein and lipid (particularly cholesterol) derived from the flea's blood meal. A similar incidence of proventricular aggregation occurred after fleas ingested whole blood or serum containing , and intact, viable bacteria were not required. The initial aggregation of in the flea gut is likely due to a spontaneous physical process termed depletion aggregation that occurs commonly in environments with high concentrations of polymers or other macromolecules and particles such as bacteria. The initial aggregation sets up subsequent binding aggregation mediated by the bacterially produced exopolysaccharide and mature biofilm that results in proventricular blockage and efficient flea-borne transmission.
IMPORTANCE
, the bacterial agent of plague, is maintained in nature in mammal-flea-mammal transmission cycles. After a flea feeds on a mammal with septicemic plague, the bacteria rapidly coalesce in the flea's digestive tract to form dense aggregates enveloped in a viscous matrix that often localizes to the foregut. This represents the initial stage of biofilm development that potentiates transmission of when the flea later bites a new host. The rapid aggregation likely occurs via a depletion-aggregation mechanism, a non-canonical first step of bacterial biofilm development. We found that the biofilm matrix is largely composed of host blood proteins and lipids, particularly cholesterol, and that the enzymatic activity of a phospholipase D (Ymt) enhances the initial aggregation. transmitted by flea bite is likely associated with this host-derived matrix, which may initially shield the bacteria from recognition by the host's intradermal innate immune response.
Topics: Yersinia pestis; Phospholipase D; Siphonaptera; Biofilms; Plague; Extracellular Polymeric Substance Matrix; Polysaccharides; Microscopy, Electron, Transmission; Proteome; Animals; Mice; Lipids
PubMed: 38722159
DOI: 10.1128/mbio.00124-24 -
Journal of Veterinary Diagnostic... Apr 2024A 57-y-old male yellow-naped parrot () was presented because of lethargy, inappetence, and weight loss. Hematology and serum biochemistry were unremarkable, and imaging...
A 57-y-old male yellow-naped parrot () was presented because of lethargy, inappetence, and weight loss. Hematology and serum biochemistry were unremarkable, and imaging revealed a mass in the distal esophagus at the coelomic inlet. The luminal diameter of the esophagus was reduced in this area, and passage of ingesta was limited. Following gavage feeding, the patient died and was submitted for autopsy. At postmortem examination, the noted mass effect was a thickening of the distal esophagus with adherent, coalescing, soft, pale-tan plaques on the mucosal surface. Additional gross findings included pale-tan, opaque feed material oozing from the dorsum of the lungs and covering the cranial air sacs. Histology of the esophagus, esophageal-proventricular junction, and proximal proventriculus revealed an unencapsulated, infiltrative, transmural neoplasm that extended from the mucosal surface deep into the muscularis, almost to the adventitia. The neoplasm was composed of cuboidal cells arranged in islands and tubules, consistent with an adenocarcinoma, a rarely reported entity in the esophagus of psittacine birds and to our knowledge not reported previously at the esophageal-proventricular junction.
PubMed: 38653775
DOI: 10.1177/10406387241247282 -
Open Veterinary Journal Jan 2024A neurological infectious viral disease, avian encephalomyelitis was initially discovered in 2-week-old commercial chicks in 1930 and classified as a neurotropic viral...
BACKGROUND
A neurological infectious viral disease, avian encephalomyelitis was initially discovered in 2-week-old commercial chicks in 1930 and classified as a neurotropic viral disease.
AIM
A neurological outbreak caused by avian encephalomyelitis virus (AEV) in young chicks was first reported in Al-Ahsa in the Kingdom of Saudi Arabia (KSA) in 2010. The aim of this article is to examine the AEV in KSA, Al-Ahsa Province.
METHODS
Gizzard, proventriculus, cerebrum, cerebellum, and medulla oblongata tissue samples were collected from infected chicks for histopathology test and molecular identification.
RESULTS
Infected chicks showed neurological signs particularly incoordination, mild head and neck tremors, stretching of legs, and lameness. The average morbidity and mortality rates were 35% and 10%, respectively. At necropsy, no obvious identifiable macroscopic lesions were found in the infected chicks. Nonsuppurative encephalomyelitis was found histopathologically in the central nervous system, mainly in the cerebral molecular layer. Microscopic lesions in the proventriculus showed masses of heavy numbers of small lymphocytes within the muscular layer. RT-PCR followed by sequence analysis revealed that The KSA strain (KJ939252) is intimately related to chicken European strains from Poland (KC912695) and the United Kingdom (AJ225173) with identity 99.6% than Chinese strains (AY225319, AY517471, and AY275539) with identity ranged between 94.6% and 95%. The phylogenetic tree analysis showed that the KSA strain is grouped in a similar clade with chicken European strains.
CONCLUSION
The pattern of disease findings was typical of vertically transmitted AEV. The spread of AEV in Saudi Arabia is most likely due to the trade of birds and bird products with European countries.
Topics: Animals; Chickens; Encephalomyelitis Virus, Avian; Phylogeny; Saudi Arabia; Encephalomyelitis
PubMed: 38633145
DOI: 10.5455/OVJ.2024.v14.i1.30 -
Proceedings of the National Academy of... Apr 2024Despite the conservation of genetic machinery involved in eye development, there is a strong diversity in the placement of eyes on the head of animals. Morphogen...
Despite the conservation of genetic machinery involved in eye development, there is a strong diversity in the placement of eyes on the head of animals. Morphogen gradients of signaling molecules are vital to patterning cues. During eye development, Wingless (Wg), a ligand of Wnt/Wg signaling, is expressed anterolaterally to form a morphogen gradient to determine the eye- versus head-specific cell fate. The underlying mechanisms that regulate this process are yet to be fully understood. We characterized ( ortholog of human SATB1), a K50 homeodomain transcription factor, as a dorsal eye gene, which regulates Wg signaling to determine eye versus head fate. Across species, Dve is expressed in the dorsal head vertex region where it regulates transcription. Second, Dve suppresses eye fate by down-regulating retinal determination genes. Third, the -expressing dorsal head vertex region is important for Wg-mediated inhibition of retinal cell fate, as eliminating the Dve-expressing cells or preventing Wg transport from these -expressing cells leads to a dramatic expansion of the eye field. Together, these findings suggest that Dve regulates Wg expression in the dorsal head vertex, which is critical for determining eye versus head fate. Gain-of-function of SATB1 exhibits an eye fate suppression phenotype similar to Dve. Our data demonstrate a conserved role for Dve/SATB1 in the positioning of eyes on the head and the interocular distance by regulating Wg. This study provides evidence that dysregulation of the Wg morphogen gradient results in developmental defects such as hypertelorism in humans where disproportionate interocular distance and facial anomalies are reported.
Topics: Animals; Humans; Drosophila Proteins; Matrix Attachment Region Binding Proteins; Wnt1 Protein; Drosophila; Retina; Transcription Factors; Gene Expression Regulation, Developmental; Drosophila melanogaster; Body Patterning
PubMed: 38588419
DOI: 10.1073/pnas.2316244121 -
Veterinary Medicine and Science May 2024The study aimed to evaluate the immunological response of layer chickens to live Newcastle disease virus vaccine using a newly developed vaccine schedule administered...
BACKGROUND
The study aimed to evaluate the immunological response of layer chickens to live Newcastle disease virus vaccine using a newly developed vaccine schedule administered via the ocular route, as well as assess the persistence of passive antibodies in layer chickens and the effectiveness of protection against strains of the virus.
METHODS
A total of 140-day-old Lohmann Brown chicks were randomly divided into seven groups, 20 chicks each. Groups 1-3 received a single eye instillation of the vaccine at ages 5, 26 and 54 days, respectively, whereas groups 4-6 received a double eye instillation. Group 7 served as non-vaccinated control group. Ten days after immunization, samples were taken from hens that had received the vaccine at ages 15, 36 and 64, as well as from control chickens that had not received the vaccine at ages 5, 15, 21 and 31.
RESULTS
A total of 10 serum samples from all chickens exhibited protective antibodies, and booster doses resulted in the highest haemagglutination inhibition titre. No significant change in antibody production was observed among layer hens (p > 0.05). The study found that the La Sota (GMT ± SD: 6.71 ± 4.96), La Sota (GMT ± SD: 8.00 ± 0.00) and thermostable I2 (GMT ± SD: 7.60 ± 6.02), vaccination schedules provided the maximum immune response in single eye instillation, whereas the HB1 (GMT ± SD: 7.11 ± 4.77), La Sota (GMT ± SD: 7.83 ± 5.76) and La Sota (GMT ± SD: 7.60 ± 6.02), combination was the second-best vaccination schedule in double eye instillation. Furthermore, maternally-derived antibodies were maintained up to 31 days of age, indicating the level of passive immunity prior to vaccination. Characteristic lesions, such as edematous and diphtheria mucosal membranes of the trachea, along with petechial and necrotic haemorrhages of the proventriculus, were observed during the necropsy of the birds that died from the challenged virus.
CONCLUSION
This study suggests that subsequent live virus vaccine by ocular route immunization is required to effectively protect against velogenic viscerotropic Newcastle disease infection. The results also highlight the importance of developing effective vaccination schedules and routes to enhance immunity against ND in layer chickens.
Topics: Animals; Female; Newcastle disease virus; Chickens; Antibodies, Viral; Vaccination; Viral Vaccines; Antibody Formation; Vaccines, Attenuated
PubMed: 38519843
DOI: 10.1002/vms3.1428 -
Poultry Science May 2024This study sought to determine the relationship among broiler performance, organ development, and indicators of microbiota colonization. A total of 1,200 two-day-old...
This study sought to determine the relationship among broiler performance, organ development, and indicators of microbiota colonization. A total of 1,200 two-day-old male Ross 308 broiler chicks, divided among 3 cohorts of equal size, were housed in battery cages, and allotted based on body weight. On study d 11, birds were weighed, and birds with BW gain within the 10th and 90th percentiles were assigned to the Slow and Fast groups, respectively. Birds (n = 30 for each group) selected on d 11 were provided water and a corn-soybean meal-based diet ad libitum while maintained individually through study d 25 (i.e., a 14-d growth period). Parameters regarding growth performance, organ and intestine weights and lengths, and intestinal volatile fatty acid concentrations were measured. All data were analyzed by one-way ANOVA using the Mixed procedure of SAS. Fast birds exhibited greater (P < 0.001) BW gain and feed intake than slow birds, but feed conversion ratio (FCR) did not differ (P = 0.19). Additionally, Slow birds had higher (P < 0.05) relative weights (% of BW) for nearly all organs on d 11 and 25, most notably the gizzard, proventriculus, pancreas, and liver. Conversely, intestinal sections were longer (P < 0.05) in the Fast birds. Measurement of gut histomorphology did not show any notable differences between growth rate groups in terms of villi height, crypt depth, or their ratio for either time-point (P > 0.05). In terms of volatile fatty acid concentrations of luminal contents, acetate concentrations were 10.2% higher (P < 0.001) in the ileum of the Slow birds compared with Fast birds on d 25. Overall, the findings suggest that total BW gain is influenced by the development of metabolically active organs, as supported by lower weight gain in Slow birds with relatively larger organ weights and shorter intestinal lengths than their Fast counterparts. The general lack of differences in fermentation end-product concentrations in luminal contents does not rule out influence of the microbiota on growth rate of broilers, which warrants further investigation.
Topics: Animals; Chickens; Male; Fermentation; Gastrointestinal Microbiome; Organ Size; Diet; Fatty Acids, Volatile; Intestines; Animal Feed; Random Allocation
PubMed: 38518667
DOI: 10.1016/j.psj.2024.103628 -
Poultry Science May 2024The present study investigated the effects of fermented bamboo powder (FPB) on gut odorant receptors (OR), intestinal health, and growth performance of dwarf...
The present study investigated the effects of fermented bamboo powder (FPB) on gut odorant receptors (OR), intestinal health, and growth performance of dwarf yellow-feathered broiler chickens. Six hundred (600) healthy 1-day-old chicks were randomly assigned into 2 groups, with 10 replicates consisting of 30 chicks each. The control group was fed a basal diet. In contrast, the experimental group was fed the basal diet supplemented with 1.0, 2.0, 4.0, and 6.0 g/kg FBP for 4 different phases, namely phase I (1-22 d), phase II (23-45 d), phase III (46-60 d), and phase IV (61-77 d), respectively. The first 2 phases were considered pretreatment (0-45 d), and the remaining were experimental (46-77 d) periods. The tissue samples were collected from phase IV. The chickens in the FBP supplementation group exhibited a significant increment in body weight gain, evisceration yield, breast, thigh, and liver weight, while also experiencing a decrease in the FCR (P < 0.05). Furthermore, the villus height, crypt depth, and villus area exhibited significant increases in the FBP group (P < 0.01). Additionally, the secretion levels of gut hormones such as glucagon-like peptide-1, peptide YY, cholecystokinin, and 5-hydroxytryptamine were significantly elevated in the serum, duodenum, jejunum, and ileum tissues in the FBP group (P < 0.05). The results of qRT-PCR indicated that ORs had responsive expression in the gizzard, proventriculus, and small intestine of chickens when fed with the FBP diet (P < 0.05). Notably, the expression of the COR1, COR2, COR4, COR6, COR8, COR9, OR52R1, OR51M1, OR1F2P, OR5AP2, and OR14J1L112 genes was stronger in the small intestines compared to the gizzard and proventriculus. In conclusion, these results suggest that the FPB plays a crucial role in growth performance, activation of ORs, and gut health and development.
Topics: Animals; Chickens; Animal Feed; Diet; Receptors, Odorant; Dietary Supplements; Random Allocation; Intestines; Sasa; Dose-Response Relationship, Drug; Fermentation; Powders; Bambusa; Male
PubMed: 38484565
DOI: 10.1016/j.psj.2024.103570 -
Poultry Science May 2024We examined the effect of the Persian Gulf algae derivates, phycocyanin (PC) and fucoidan (FUC), on production performance, egg quality, intestinal histomorphology,...
We examined the effect of the Persian Gulf algae derivates, phycocyanin (PC) and fucoidan (FUC), on production performance, egg quality, intestinal histomorphology, ileal microflora, and egg yolk biochemistry of laying Japanese quail. A total of 250 six-wk-old Japanese quails with an average body weight of 215 ± 10 g were allocated to 5 treatments, 5 replicates and 10 birds in each replicate in a completely randomized design. The treatment groups received PC (from Spirulina platensis) and FUC (from brown seaweed) in their drinking water while control groups did not. Treatment groups received PC and FUC at 20 or 40 mg/L levels (denoted as PC20, PC40, FUC20, and FUC40, respectively). All birds were fed the same diet. All treatments significantly improved the percentage of hen day egg production (HDEP) (P = 0.002), egg mass (P = 0.002), and feed conversion ratio (FCR) (P = 0.022) but no difference was noted in egg weight (EW) and feed intake (FI). Different levels of PC and FUC significantly increased the thickness of eggshells (P = 0.022); however, the weight of the digestive tract (liver, spleen, proventriculus, gizzard, and pancreas) and oviduct was not affected. Algal derivates improved the villus height (P = 0.007) and crypt depth (P = 0.007) of the duodenum, as well as, the villus height (P = 0.005) and crypt depth (P = 0.026) of the jejunum. Both algal derivates positively affected the intestinal microflora (populations of Lactobacillus (P = 0.017), Coliform (P = 0.005), and Clostridium (P = 0.000)) whereas aerobic bacteria were unaffected. Yolk cholesterol P = 0.012) and yolk malondialdehyde P = 0.050) content were significantly reduced in experimental treatments compared to the control group. In conclusion, our results showed that the treatment of laying Japanese quails with algal derivates positively affects quail performance, intestinal morphology, intestinal microflora, and yolk cholesterol and malondialdehyde. Additional studies exploring optimal dosages and mechanisms of action is warranted to fully understand the scope of the algae derivates in poultry production.
Topics: Animals; Coturnix; Diet; Animal Feed; Gastrointestinal Microbiome; Female; Polysaccharides; Egg Yolk; Phycocyanin; Dietary Supplements; Random Allocation; Spirulina; Intestines; Ileum
PubMed: 38471233
DOI: 10.1016/j.psj.2024.103605 -
Proceedings of the National Academy of... Mar 2024The animal foregut is the first tissue to encounter ingested food, bacteria, and viruses. We characterized the adult Drosophila foregut using transcriptomics to better...
The animal foregut is the first tissue to encounter ingested food, bacteria, and viruses. We characterized the adult Drosophila foregut using transcriptomics to better understand how it triages consumed items for digestion or immune response and manages resources. Cell types were assigned and validated using GFP-tagged and Gal4 reporter lines. Foregut-associated neuroendocrine cells play a major integrative role by coordinating gut activity with nutrition, the microbiome, and circadian cycles; some express clock genes. Multiple epithelial cell types comprise the proventriculus, the central foregut organ that secretes the peritrophic matrix (PM) lining the gut. Analyzing cell types synthesizing individual PM layers revealed abundant mucin production close to enterocytes, similar to the mammalian intestinal mucosa. The esophagus and salivary gland express secreted proteins likely to line the esophageal surface, some of which may generate a foregut commensal niche housing specific gut microbiome species. Overall, our results imply that the foregut coordinates dietary sensing, hormonal regulation, and immunity in a manner that has been conserved during animal evolution.
Topics: Animals; Drosophila; Epithelial Cells; Cell Count; Nutritional Status; Body Fluids; Mammals
PubMed: 38442150
DOI: 10.1073/pnas.2318760121 -
Development (Cambridge, England) Mar 2024Vision is mainly based on two different tasks, object detection and color discrimination, carried out by photoreceptor (PR) cells. The Drosophila compound eye consists...
Vision is mainly based on two different tasks, object detection and color discrimination, carried out by photoreceptor (PR) cells. The Drosophila compound eye consists of ∼800 ommatidia. Every ommatidium contains eight PR cells, six outer cells (R1-R6) and two inner cells (R7 and R8), by which object detection and color vision are achieved, respectively. Expression of opsin genes in R7 and R8 is highly coordinated through the instructive signal from R7 to R8, and two major ommatidial subtypes are distributed stochastically; pale type expresses Rh3/Rh5 and yellow type expresses Rh4/Rh6 in R7/R8. The homeodomain protein Defective proventriculus (Dve) is expressed in yellow-type R7 and in six outer PRs, and it is involved in Rh3 repression to specify the yellow-type R7. dve mutant eyes exhibited atypical coupling, Rh3/Rh6 and Rh4/Rh5, indicating that Dve activity is required for proper opsin coupling. Surprisingly, Dve activity in R1 is required for the instructive signal, whereas activity in R6 and R7 blocks the signal. Our results indicate that functional coupling of two different neurons is established through signaling pathways from adjacent neurons that are functionally different.
Topics: Animals; Drosophila; Opsins; Color Vision; Drosophila Proteins; Neurons; Signal Transduction; Photoreceptor Cells, Invertebrate; Drosophila melanogaster
PubMed: 38421315
DOI: 10.1242/dev.202388